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  • 301.
    Lindeberg, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Multiple nanowire via interconnects in flexible printed circuit boards2009In: Smart Systems Integration 2009, 2009, p. 6-11Conference paper (Other academic)
  • 302.
    Lindeberg, Mikael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Yousef, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Röjdegård, Henrik
    Martin, Hans
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Flexible PCB Vertical Thermopile IR Sensor Proc. Solid-State Sensors, Actuators and Microsystems Conference2007Conference paper (Refereed)
  • 303.
    Liu, Zhenhua
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Fornell, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Barbe, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    On-chip background dilution in droplets with high particle recovery using acoustophoresis2019In: Biomicrofluidics, ISSN 1932-1058, E-ISSN 1932-1058, Vol. 13, article id 064123Article in journal (Refereed)
    Abstract [en]

    Droplet microfluidics has shown great potential for on-chip biological and chemical assays. However, fluid exchange in droplet microfluidics with high particle recovery is still a major bottleneck. Here, using acoustophoresis, we present for the first time a label-free method to achieve continuous background dilution in droplets containing cells with high sample recovery. The system comprises droplet generation, acoustic focusing, droplet splitting, picoinjection, and serpentine mixing on the same chip. The capacities of the picoinjection and the droplet split to dilute the background fluorescent signal in the droplets have been characterized. The sample recovery at different droplet split ratios has also been characterized. The results show a maximum of 4.3-fold background dilution with 87.7% particle recovery. We also demonstrated that the system can be used to dilute background fluorescent signal in droplets containing either polystyrene particles or endothelial cells.

  • 304.
    Liu, Zhenhua
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Fornell, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    A continuous on-chip droplet washing platform with high bead recovery by acoustofluidics2019Conference paper (Other academic)
    Abstract [en]

    Acoustofluidics is a promising technology for manipulation of fluids and particles in microchannels, and the technology has the ability to sort beads and cells in continuous flow with very high efficiency. Recently acoustofluidics has also been applied in segmental flow for positioning beads inside droplets. Compared with single-phase systems, droplet microfluidics has the advantages of faster reactions, lower cross-contamination and higher throughput. Moreover, the small size of the droplets makes them ideal as cultivation and reaction vials for single cell analysis. However, as the droplets are so small one challenge is to wash the droplets before image analysis. P. Mary et al. developed a microfluidic platform for droplet wash, whichis based on electrocoalescence and droplet break-ups with equal volume. The background noise was decreased significantly, however the recovery of the encapsulated cells was low. Alternative solutions have been presented by H. Lee et al. and S.R. Doonan et al. but as the bead recovery is controlled via magnetophoresis, the technology is only applicable to magnetic samples. Here we present a droplet microfluidic platform that enables background dilution with high bead recovery in a label-free manner using acoustophoresis.

  • 305.
    Liu, Zhenhua
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Fornell, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Droplet Dilution Unit Operation Including Bead Washing Using Integrated Acoustophoresis2019Conference paper (Other academic)
    Abstract [en]

    This paper presents a microfluidic platform for on-chip droplet dilution where the bead recovery also can be controlled. The droplets containing 10 µm polystyrene beads can be diluted with high bead recovery. This platform involves 5 steps for on-chip dilution of the droplets: droplet generation, bead focusing, droplet splitting, pico-injection and serpentine mixing. Background signal in the droplets is significantly reduced with maintained bead recovery by this on-chip dilution method. The technology is applicable to many types of samples and does not require any labelling of the bioparticles.

  • 306. Liu, Zhenhua
    et al.
    Xu, Wenchao
    Hou, Zining
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A Rapid Prototyping Technique for Microfluidics with High Robustness and Flexibility2016In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 7, no 11, article id 201Article in journal (Refereed)
    Abstract [en]

    In microfluidic device prototyping, master fabrication by traditional photolithography is expensive and time-consuming, especially when the design requires being repeatedly modified to achieve a satisfactory performance. By introducing a high-performance/cost-ratio laser to the traditional soft lithography, this paper describes a flexible and rapid prototyping technique for microfluidics. An ultraviolet (UV) laser directly writes on the photoresist without a photomask, which is suitable for master fabrication. By eliminating the constraints of fixed patterns in the traditional photomask when the masters are made, this prototyping technique gives designers/researchers the convenience to revise or modify their designs iteratively. A device fabricated by this method is tested for particle separation and demonstrates good properties. This technique provides a flexible and rapid solution to fabricating microfluidic devices for non-professionals at relatively low cost.

  • 307.
    Lotfi, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Palmer, Kristoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kratz, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hybrid microtransmitter for free-space optical spacecraft communication: design, manufacturing, and characterization2009In: Proc. SPIEPhotonics West, MOEMS and Miniaturized Systems VIII, Jan 24-29, San Jose, CA, 2009, p. 72080N-12-Conference paper (Other academic)
    Abstract [en]

    Opticalintra-communication links are investigated by several currently operational qualification missions.Compared with RF communication systems, the optical domain obtains awider bandwidth, enables miniaturized spacecraft and reduced power consumption. Inthis project, a microtransmitter is designed and manufactured for formationflying spacecraft with transmission rates of 1 Gbit/s. Simulations inMatlab and Simulink show that a BER of 10-9 canbe achieved with aperture sizes of 1 cm and atransmitter output peak power of 12 mW for a distanceof 10 km. The results show that the performance ofthe communication link decreases due to mechanical vibrations in thespacecraft together with a narrow laser beam. A dual-axis microactuatordesigned as a deflectable mirror has been developed for thelaser beam steering where the fabrication is based on adouble-sided, bulk micromachining process. The mirror actuates by joints consistingof v-grooves filled with SU-8 polymer. The deflection is controlledby integrated resistive heaters in the joints causing the polymerto expand thermally. Results show that the mirror actuates 20-30°in the temperature interval 25-250°C. Flat Fresnel lenses made ofPyrex 7740 are used to collimate the laser beam. Theselenses are simulated in the Comsol software and optimized fora 670 nm red VCSEL. The lenses are manufactured usinglithography and reactive ion etching. All tests are made ina normal laboratory environment, but the effect of the spaceenvironment is discussed

  • 308. Lu, Xi
    et al.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Effati, Pedram
    Pal Singh, V
    Poon, JF
    Engman, Lars
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Novel selenium- and tellurium-based antioxidants as modulators of inflammatory response2015Conference paper (Refereed)
  • 309.
    Lu, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Singh, Vijay Pal
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Effati, Pedram
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Poon, Jia-Fei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Marjam, Karlsson Ott
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Selenium- and tellurium-based antioxidants for modulating inflammation and effects on osteoblastic activity2017In: Antioxidants, E-ISSN 2076-3921, Vol. 6, no 13, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Increased oxidative stress plays a significant role in the etiology of bone diseases. Heightened levels of H2O2 disrupt bone homeostasis, leading to greater bone resorption than bone formation. Organochalcogen compounds could act as free radical trapping agents or glutathione peroxidase mimetics, reducing oxidative stress in inflammatory diseases. In this report, we synthesized and screened a library of organoselenium and organotellurium compounds for hydrogen peroxide scavenging activity, using macrophagic cell lines RAW264.7 and THP-1, as well as human mono- and poly-nuclear cells. These cells were stimulated to release H2O2, using phorbol 12-myristate 13-acetate, with and without organochalogens. Released H2O2 was then measured using a chemiluminescent assay over a period of 2 h. The screening identified an organoselenium compound which scavenged H2O2 more effectively than the vitamin E analog, Trolox. We also found that this organoselenium compound protected MC3T3 cells against H2O2 -induced toxicity, whereas Trolox did not. The organoselenium compound exhibited no cytotoxicity to the cells and had no deleterious effects on cell proliferation, viability, or alkaline phosphatase activity. The rapidity of H2O2 scavenging and protection suggests that the mechanism of protection is due to the direct scavenging of extracellular H2O2. This compound is a promising modulators of inflammation and could potentially treat diseases involving high levels of oxidative stress.

  • 310.
    Magnusson, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flödesmätning i smörjoljesystem med bärbar ultraljudsmätare: Underlag till en arbetsinstruktion2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

     This thesis was conducted at Siemens

    Industrial Turbomachinery (SIT) under a period

    of ten weeks. Siemens service department at

    this company takes care of the aftermarket of

    the turbines and provides inspection, spare

    parts and measures to increase the efficiency of

    the machines. SIT provides also oil lubrication

    systems. Because the turbomachines have a

    variety of pipe systems and flows, it may need

    to perform flow measurements for

    troubleshooting, optimization and detection of

    oil leaks. Through the years, SIT has gathered

    data from flow measurements that may suggest

    that a tubomachine system is operating at over

    or under the designed capacity. However, SIT

    does not have enough knowledge about proper

    flow measurements, evaluation of the test

    results and necessary measures to be taken,

    therefor no clear work instruction has been

    established. The goal of this work is therefore to

    provide a document about applicable flow

    measurement methods, based on which the

    company at a later phase can establish

    necessary work instruction.

    In order to write this document, necessary

    theory was gathered in order to understand

    how oil lubrication systems and flow

    measurement systems work. The author and

    some of SIT employees attended a training

    course in portable ultrasound measurement

    system provided by PEMA Control AB in

    Gothenburg. After the course, practical data

    collection and a summary of the entire flow

    measurement process was documented. This

    process was later tested in two experiments.

    The experiment results, as well as the practical

    measurement steps were then analyzed and

    discussed. After the analysis and evaluation a

    proposal of measurement procedure was

    compiled.

    Conclusions of the report include

    recommendations for improvement of the

    measurement process. The recommendations

    include necessary information about what the

    staff should think about before-, during- and

    after the measurement. This is to make the

    measurement as efficient as possible and to

    minimize the risk of engine failure and personal

    injuries. Other recommendations were to add

    necessary equipment to the existing flow

    measurement bag.

  • 311.
    Malik, Amer
    et al.
    Royal Institute of Technology (KTH).
    Ogden, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Amberg, Gustav
    Royal Institute of Technology (KTH).
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Modeling and Analysis of a Phase Change Material Thermohydraulic Membrane Microactuator2013In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 22, no 1, p. 186-194Article in journal (Refereed)
    Abstract [en]

    Presented in this paper is a finite-element-method-based model for phase change material actuators, modeling the active material as a fluid as opposed to a solid. This enables the model to better conform to localized loads and offering the opportunity to follow material movement in enclosed volumes. Modeling, simulation, and analysis of an electrothermally activated paraffin microactuator have been conducted. The paraffin microactuator used for the analysis in this study exploits the large volumetric expansion of paraffin upon melting, which, combined with its low compressibility in the liquid state, allows for high hydraulic pressures to be generated. The purpose of this study is to supply a geometry-independent model of such a microactuator through the implementation of a fluid model rather than a solid one, which has been utilized in previous studies. Numerical simulations are conducted at different frequencies of the heating source and for different geometries of the microactuator. The results are compared with the empirical data obtained on a close to identical paraffin microactuator, which clearly show the advantages of a fluid model instead of a solid-state approximation.

  • 312.
    Malmström, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik .
    A lab-on-a-chip device for photonic sensing of single cells2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cells are the smallest living units and together they form all living organisms on earth. The cells are not only the building blocks of all living things, they also possess the most important information about life. A deeper understanding of these units may reveal hidden secrets about difficultly cured diseases, memory and learning, among others.

    Today’s techniques have problems such as low sensitivity, lethal preparation steps for the cells and overlaps in result spectra. Microfluidics has shown to be a useful tool allowing improved dynamic control, high throughput and sensitivity in nanoliters.

    The aim with this project is to design a microfluidic system for future integration with photonic sensors. Three different designs were developed, one design with the aim to integrate with photonic sensors and two for cell trapping only. Simulations and analytical calculations were performed to verify the requirements of single cell trapping. Simulation and analytical calculation results consorted, except for the ladder design. Moreover, strength calculations were performed for the sensor, to verify that it could handle the high pressures.

    A fabrication process was developed and an OSTE polymer was chosen as a suitable material. The transparency of the OSTE for fluorescent signals was studied. Results from the fabrication show proper lithography and molding as well as flow through channels. However, bubbles tend to appear in the channels. A rough surface of the chip appeared to primarily come from defects and filth on mask and mold. Three different connector solutions were tested, but they could not stand the high pressures.

    The work in this project has taken the development one step closer to the final goal to integrate photonic biosensors with a microfluidic system enabling single cell sensing. 

  • 313.
    Mao, Fang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Lindeberg, Mikael
    JonDeTech AB, Uppsala.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A polymer foil non-contact IR temperature sensor with a thermoresistor integrated on the back of a vertically configured thermopile2012In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 179, p. 56-61Article in journal (Refereed)
    Abstract [en]

    A very thin non-contact IR temperature sensor has been fabricated in a polymer foil. A thermoresistor was placed in the isothermal back-layer of a vertical configured IR-sensor. The IR-sensor is a thermopile consisting of through-the-foil thermocouple legs in a flexible polyimide foil, and the integration of a thermoresistor to one of its surfaces enables use of the sensor for non-contact temperature measurements. The size of the sensor is 3 mm x 3 mm and the thickness is less than 0.2 mm. The sensor can easily be surface mounted to printed circuit boards. An ion track technique followed by lithographically controlled electroplating of nanowires and thin film deposited interconnects are used to fabricate the infrared sensor. The thin film nickel thermoresistor was fabricated using evaporation. Layers of Parylene C was used for electric insulation and protection to improve environmental stability. In the temperature range of 20-55 degrees C, the thermoresistor shows good linearity. Some initial decrease in resistance was seen at 105 degrees C whereafter the resistance stabilized. The IR temperature sensor was characterized, and for temperatures near room temperature a simple linear equation using the voltage response and temperature of the thermoresistor as the only input parameters was curve fitted to the experimental data. The difference between the measured and the calculated object temperature is less than 0.5 degrees C using a confidence level of 95%.

  • 314.
    Mawet, Dimitri
    et al.
    European Southern Observatory, Chile.
    Murakami, Naoshi
    Hokkaido University, Japan.
    Delacroix, Christian
    University of Liège, Belgium.
    Serabyn, Eugene
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Absil, Olivier
    University of Liège, Belgium.
    Baba, Naoshi
    Hokkaido University, Japan.
    Baudrand, Jacques
    LESIA, Observatoire de Paris, France.
    Boccaletti, Anthony
    LESIA, Observatoire de Paris, France.
    Burruss, Rick
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Chipman, Russell
    University of Arizona, USA.
    Forsberg, Pontus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Habraken, Serge
    University of Liège, Belgium.
    Hamaguchi, Shoki
    Hokkaido University, Japan.
    Hanot, Charles
    LESIA, Observatoire de Paris, France.
    Ise, Akitoshi
    Hokkaido University, Japan.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kern, Bryan
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Krist, John
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Kuhnert, Andreas
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Levine, Marie
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Liewer, Kurt
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    McClain, Stephen
    University of Arizona, USA.
    McEldowney, Scott
    Microsoft, USA.
    Mennesson, Bertrand
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Moody, Dwight
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Murakami, Hiroshi
    Japan Aerospace Exploration Agency, Japan.
    Niessner, Albert
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Nishikawa, Jun
    National Astronomical Observatory of Japan, Japan.
    O’Brien, Nada
    JDSU, USA.
    Oka, Kazuhiko
    Hokkaido University, Japan.
    Park, Peggy
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Piron, Pierre
    University of Liège, Belgium.
    Pueyo, Laurent
    Space Telescope Science Institute, USA.
    Riaud, Pierre
    LESIA, Observatoire de Paris, France.
    Sakamoto, Moritsugu
    Hokkaido University, Japan.
    Tamura, Motohide
    Japan Aerospace Exploration Agency, Japan.
    Trauger, John
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Shemo, David
    JDSU, USA.
    Surdej, Jean
    University of Liège, Belgium.
    Tabiryan, Nelson
    BEAM Engineering for Advanced Measurements Co., USA.
    Traub, Wesley
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Wallace, James
    Jet Propulsion Laboratory - California Institute of Technology, USA.
    Yokochi, Kaito
    Tokyo University of Agriculture and Technology, Japan.
    Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe2011Conference paper (Refereed)
  • 315. Mege, Daniel
    et al.
    Grygorczuk, Jerzy
    Gurgurewicz, Joanna
    Wisniewski, Lukasz
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    The Planetary Highland Terrain Hopper (HOPTER): the right way to jump into conclusions2015Conference paper (Refereed)
    Abstract [en]

    Comprehensive understanding of the principles governing the geological activity of the Earth was obtained in continental and oceanic mountains. It is not expected that the principles governing the overall geologic activity and evolution of other planetary bodies such as Mars will be understood if exploration is limited to nearly flat terrains, either imposed by the used exploration platform capabilities, the risk of getting stuck, or by the time required to cross the border of a landing ellipse. Surface exploration of mountains is additionally to be coupled to two-or three-dimensional geophysical surveys to correlate the surface observations with deeper processes. On the small bodies where ultra-low gravity prevails, the weight of wheel-driven platforms is not sufficient to generate the friction at the contact with the ground that is required to trigger motion of the rover relative to the ground. Under such circumstances, hopping is one of the mobility solutions. We present a new locomotion system, the hopter platform, which is adapted to these challenges on Solar System bodies having a gravity field lower than on Earth. The hopter is a robust, versatile and highly manoeuvrable platform based on simple mechanical concepts that accurately jumps to distances of meters to tens of meters and more, depending on the gravity field of the studied body. Its low mass of 10kg (including up to 5 kg of miniaturized payload), makes it possible to simultaneously launch several hopters to work as a fractionated explorer at a very competitive cost. After reviewing the payload that may be placed onboard hopters, we illustrate the scientific capabilities of hopters and hopter networks in performing basic geologic observations at distinct study sites in a variety of geological environments, obtaining data along steep geological cross sections, surveying geophysical anomalies in the subsurface, prospecting resources, monitoring micro-environments, meteorological events, and geodetic deformation, or characterizing dust activity on Mars, the Moon, and Phobos.

  • 316. Mege, Daniel
    et al.
    Gurgurewicz, Joanna
    Grygorczuk, Jerzy
    Wisniewski, Lukasz
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    The Highland Terrain Hopper (HOPTER): Concept and usecases of a new locomotion system for the exploration of lowgravity Solar System bodies2016In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 121, p. 200-220Article in journal (Refereed)
    Abstract [en]

    Comprehensive understanding of the principles governing the geological activity of theEarth was obtained in continental and oceanic mountains. It is not expected that theprinciples governing the overall geologic activity and evolution of other planetary bodiessuch as Mars will be understood if exploration is limited to nearlyflat terrains, eitherimposed by the used exploration platform capabilities, the risk of getting stuck, or by thetime required to cross the border of a landing ellipse. Surface exploration of mountains isadditionally to be coupled to two- or three-dimensional geophysical surveys to correlatethe surface observations with deeper processes. On the small bodies where ultra-lowgravity prevails, the weight of wheel-driven platforms is not sufficient to generate thefriction at the contact with the ground that is required to trigger motion of the roverrelative to the ground. Under such circumstances, hopping is one of the mobility solutions.We present a new locomotion system, the hopter platform, which is adapted to thesechallenges on Solar System bodies having a gravityfield lower than on Earth. The hopter isa robust, versatile and highly manoeuvrable platform based on simple mechanical con-cepts that accurately jumps to distances of metres to tens of metres and more, dependingon the gravityfield of the studied body. Its low mass of 10 kg (including up to 3 kg ofminiaturised payload), makes it possible to simultaneously launch several hopters to workas a fractionated explorer at a very competitive cost. After reviewing the payload that maybe placed onboard hopters, we illustrate the scientific capabilities of hopters and hopternetworks in performing basic geologic observations at distinct study sites in a variety ofgeological environments, obtaining data along steep geological cross sections, surveyinggeophysical anomalies in the subsurface, prospecting resources, monitoring micro-environments, meteorological events, and geodetic deformation, or characterizing dustactivity on Mars, the Moon, and Phobos.

  • 317. Mege, Daniel
    et al.
    Gurgurewicz, Joanna
    Grygorczuk, Jerzy
    Wiśniewski, Lukasz
    Beucler, Eric
    Carrère, Véronique
    Dyment, Jérome
    Gritsevich, Maria
    Langlais, Benoit
    Peltoniemi, Jouni
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zubko, Nataliya
    Principles and examples of scientific applications of the HOPTER jumping robot on Phobos2016Conference paper (Refereed)
  • 318.
    Mestres, Gemma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Espanol, Montserrat
    Department of Engineering Sciences and Metallurgy, Technical University of Catalonia, Diagonal 647, 08028 Barcelona, Spain.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Tenje, Maria
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden.
    Ott, Marjam
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Evaluation of Biocompatibility and Release of Reactive Oxygen Species of Aluminum Oxide-Coated Materials2016In: ACS Omega, ISSN 2470-1343, Vol. 1, no 4, p. 706-713Article in journal (Refereed)
    Abstract [en]

    Surface properties of biomaterials can strongly influence biomaterial−host interactions. For this reason, coating processes open a wide range of possibilities to modulate the fate of a biomaterial in the body. This study evaluates the effect of a coating material intended for drug delivery capsules on biocompatibility and the release of reactive oxygen species (ROS), that is, respiratory burst in macrophages that indicates acute inflammation. In parallel with a new approach to develop drug-delivery capsules by directly coating solid-state drug particles, in this study, glass slides and silicon nanoparticles (NPs) were coated with aluminum oxide (Al2O3) using atomic layer deposition. Different sizes of NPs (20 and 310 nm) were suspended at different concentrations (10, 100, and 1000 μg/mL) and were evaluated. The homogeneous coating of slides was proved using X-ray photoelectron spectroscopy, and the coating on NP was observed using transmission electron microscopy. Human dermal fibroblasts and human osteoblasts were able to proliferate on the coated slides and in the presence of a suspension of coated NPs (20 and 310 nm) at a low concentration (10 μg/mL). The macrophages released ROS only when in contact with NPs at a concentration of 1000 μg/mL, where the 20 nm NPs caused a higher release of ROS than the 310 nm NPs. This study shows that Al2O3 coatings do not affect the cells negatively and that the cell viability was compromised only when in contact with a high concentration (1000 μg/mL) of smaller (20 nm) NPs. 

  • 319.
    Mestres, Gemma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Fernandez-Yague, Marc Antoni
    Technical University of Catalonia (UPC).
    Pastorino, David
    Technical University of Catalonia.
    Montufar, Edgar Benjamin
    Brno University of Technology.
    Canal, Cristina
    Technical University of Catalonia.
    Manzanares-Céspedes, Maria-Cristina
    University of Barcelona.
    Ginebra, Maria-Pau
    Technical University of Catalonia.
    In vivo efficiency of antimicrobial inorganic bone grafts in osteomyelitis Treatments2019In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 97, p. 84-95Article in journal (Refereed)
    Abstract [en]

    The purpose of the present work was to evaluate in vivo different antimicrobial therapies to eradicate osteomyelitis created in the femoral head of New Zealand rabbits. Five phosphate-based cements were evaluated: calcium phosphate cements (CPC) and calcium phosphate foams (CPF), both in their pristine form and loaded with doxycycline hyclate, and an intrinsic antimicrobial magnesium phosphate cement (MPC; not loaded with an antibiotic). The cements were implanted in a bone previously infected with Staphylococcus aureus to discern the effects of the type of antibiotic administration (systemic vs. local), porosity (microporosity, i.e. <5 μm vs. macroporosity, i.e. >5 μm) and type of antimicrobial mechanism (release of antibiotic vs. intrinsic antimicrobial activity) on the improvement of the health state of the infected animals. A new method was developed, with a more comprehensive composite score that integrates 5 parameters of bone infection, 4 parameters of bone structural integrity and 4 parameters of bone regeneration. This method was used to evaluate the health state of the infected animals, both before and after osteomyelitis treatment. The results showed that the composite score allows to discern statistically significant differences between treatments that individual evaluations were not able to identify. Despite none of the therapies completely eradicated the infection, it was observed that macroporous materials (CPF and CPFd, the latter loaded with doxycycline hyclate) and intrinsic antimicrobial MPC allowed a better containment of the osteomyelitis. This study provides novel insights to understand the effect of different antimicrobial therapies in vivo, and a promising comprehensive methodology to evaluate the health state of the animals was developed. We expect that the implementation of such methodology could improve the criteria to select a proper antimicrobial therapy.

    The full text will be freely available from 2020-11-28 11:07
  • 320.
    Mestres, Gemma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kugiejko, Karol
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pastorino, David
    Unosson, Johanna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ginebra, Maria-Pau
    Tech Univ Catalonia UPC, Dept Mat Sci & Met, Biomat Biomech & Tissue Engn Grp, Barcelona 08028, Spain.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Changes in the drug release pattern of fresh and set simvastatin-loaded brushite cement2016In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 58, p. 88-96Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements are synthetic bone graft substitutes able to set at physiological conditions.They can be applied by minimally invasive surgery and can also be used as drug delivery systems.Consequently, the drug release pattern from the cement paste (fresh cement) is of high clinical interest.However, previous studies have commonly evaluated the drug release using pre-set cements only.Therefore, the aim of this work was to determine if the time elapsed from cement preparation untilimmersion in the solution (3 min for fresh cements, and 1 h and 15 h for pre-set cements) had aninfluence on its physical properties, and correlating these to the drug release profile. Simvastatin wasselected as a model drug, while brushite cement was used as drug carrier. This study quantified howthe setting of a material reduces the accessibility of the release media to the material, thus preventingdrug release. A shift in the drug release pattern was observed, from a burst-release for fresh cements toa sustained release for pre-set cements.

  • 321.
    Mestres, Gemma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Perez, Roman A.
    Universitat Internacional de Catalunya (Spain).
    d'Elía, Noelia
    Universidad Nacional del Sur (Argentina).
    Barbe, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Advantages of microfluidic systems for studying cell-biomaterial interactions: focus on bone regeneration applications2019In: Biomedical Physics & Engineering Express, ISSN 2057-1976, Vol. 5, no 3, article id 032001Article, review/survey (Refereed)
    Abstract [en]

    The poor correlation between in vitro and in vivo studies emphasises the lack of a reliable methodology for testing the biological properties of biomaterials in the bone tissue regeneration field. Moreover, the success of clinical trials is not guaranteed even with promising results in vivo. Therefore, there is a need for a more physiologically relevant in vitro model to test the biological properties of biomaterials. Microfluidics, which is a field concerning the manipulation and control of liquids at the submillimetre scale, can use channel geometry, cell confinement and fluid flow to recreate a physiological-like environment. This technology has already proven to be a powerful tool in studying the biological response of cells in defined environments, since chemical and mechanical inputs as well as cross-talk between cells can be finely controlled. Moving a step further in complexity, biomaterials can be integrated into microfluidic systems to evaluate biomaterial-cell interactions. The biomaterial- microfluidics combination has the potential to produce more physiologically relevant models to better screen the biological interactions established between biomaterials and cells. This review is divided into two main sections. First, several possible cell-based assays for bone regeneration studies in microfluidic systems are discussed. Second, and the ultimate goal of the review, is to discuss how the gap between in vitro and in vivo studies can be shortened by bridging the biomaterials and microfluidics fields.

    The full text will be freely available from 2020-04-06 08:51
  • 322.
    Mestres, Gemma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sjögren, Frida
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thumula, Venkata
    Wolff, Anette
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Microstructured 3D cell culture scaffolds2016Conference paper (Refereed)
  • 323.
    Mestres, Gemma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wolff, Anette
    Hilborn, Jöns
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Microfluidic system with integrated 3D cell culture matrix: towards more in vivo-like organ-on-chip models2016Conference paper (Refereed)
  • 324.
    Montazerolghaem, Maryam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ning, Yi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Karlsson Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simvastatin and zinc synergistically enhance osteoblasts activityand decrease the acute response of inflammatory cells2016In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 2, article id 23Article in journal (Refereed)
    Abstract [en]

    Several ceramic biomaterials have been suggested as promising alternatives to autologous bone to replace or restore bone after trauma or disease. The osteoinductive potential of most scaffolds is often rather low by themselves and for this reason growth factors or drugs have been supplemented to these synthetic materials. Although some growth factors show good osteoinductive potential their drawback is their high cost and potential severe side effects. In this work the combination of the well-known drug simvastatin (SVA) and the inorganic element Zinc (Zn) is suggested as a potential additive to bone grafts in order to increase their bone regeneration/ formation. MC3T3-E1 cells were cultured with Zn (10 and 25 mu M) and SVA (0.25 and 0.4 mu M) for 10 days to evaluate proliferation and differentiation, and for 22 days to evaluate secretion of calcium deposits. The combination of Zn (10 mu M) and SVA (0.25 mu M) significantly enhanced cell differentiation and mineralization in a synergetic manner. In addition, the release of reactive oxygen species (ROS) from primary human monocytes in contact with the same concentrations of Zn and SVA was evaluated by chemiluminescence. The combination of the additives decreased the release of ROS, although Zn and SVA separately caused opposite effects. This work shows that a new combination of additives can be used to increase the osteoinductive capacity of porous bioceramics.

  • 325.
    Motisuke, Mariana
    et al.
    Bioceramics Laboratory, Science and Technology Institute, UNIFESP, 12231-280 São José dos Campos, SP, Brazil.
    Mestres, Gemma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Renó, Caroline O.
    Bioceramics Laboratory, Science and Technology Institute, UNIFESP, 12231-280 São José dos Campos, SP, Brazil.
    Carrodeguas, Raúl G.
    Department of Ceramics, Institute of Ceramics and Glass (ICV), CSIC, Kelsen 5, 28049 Madrid, Spain.
    Zavaglia, Cecília A.C.
    Labiomec, Mechanical Engineering School, State University of Campinas, 13083-860 Campinas, SP, Brazil.
    Ginebra, Maria-Pau
    Engineering Sciences and Metallurgy Dpt., Technical University of Catalonia, Diagonal 647, 08028 Barcelona, Spain.
    Influence of Si substitution on the reactivity of α-tricalcium phosphate2017In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 75, p. 816-821Article in journal (Refereed)
    Abstract [en]

    Silicon substituted calcium phosphates have been widely studied over the last ten years due to their enhanced osteogenic properties. Notwithstanding, the role of silicon on α-TCP reactivity is not clear yet. Therefore, the aim of this work was to evaluate the reactivity and the properties of Si-α-TCP in comparison to α-TCP. Precursor powders have similar properties regarding purity, particle size distribution and specific surface area, which allowed a better comparison of the Si effects on their reactivity and cements properties. Both Si-α-TCP and α-TCP hydrolyzed to a calcium-deficient hydroxyapatite when mixed with water but their conversion rates were different. Si-α-TCP exhibited a slower setting rate than α-TCP, i.e. kSSA for Si-TCP (0.021 g·m− 2·h− 1) was almost four times lower than for α-TCP (0.072 g·m− 2·h− 1). On the other hand, the compressive strength of the CPC resulting from fully reacted Si-α-TCP was significantly higher (12.80 ± 0.38 MPa) than that of α-TCP (11.44 ± 0.54 MPa), due to the smaller size of the entangled precipitated apatite crystals.

  • 326.
    Mège, Daniel
    et al.
    Polish Acad Sci, Space Res Ctr, Bartycka St 18A, PL-00716 Warsaw, Poland.;Univ Nantes, Lab Planetol & Geodynam, CNRS UMR 6112, BP 92208, F-44322 Nantes 3, France.;OSUNA, CNRS, UMS 3281, Lyon, France..
    Gurgurewicz, Joanna
    Polish Acad Sci, Space Res Ctr, Bartycka St 18A, PL-00716 Warsaw, Poland.;Polish Acad Sci, Inst Geol Sci, Res Ctr Wroclaw, Podwale St 75, PL-50449 Wroclaw, Poland..
    Grygorczuk, Jerzy
    Polish Acad Sci, Space Res Ctr, Bartycka St 18A, PL-00716 Warsaw, Poland.;Astronika Sp Zoo, Bartycka St 18, PL-00716 Warsaw, Poland..
    Wisniewski, Lukasz
    Polish Acad Sci, Space Res Ctr, Bartycka St 18A, PL-00716 Warsaw, Poland.;Astronika Sp Zoo, Bartycka St 18, PL-00716 Warsaw, Poland..
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    The Highland Terrain Hopper (HOPTER): Concept and use cases of a new locomotion system for the exploration of low gravity Solar System bodies2016In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 121, p. 200-220Article in journal (Refereed)
    Abstract [en]

    Comprehensive understanding of the principles governing the geological activity of the Earth was obtained in continental and oceanic mountains. It is not expected that the principles governing the overall geologic activity and evolution of other planetary bodies such as Mars will be understood if exploration is limited to nearly flat terrains, either imposed by the used exploration platform capabilities, the risk of getting stuck, or by the time required to cross the border of a landing ellipse. Surface exploration of mountains is additionally to be coupled to two- or three-dimensional geophysical surveys to correlate the surface observations with deeper processes. On the small bodies where ultra-low gravity prevails, the weight of wheel-driven platforms is not sufficient to generate the friction at the contact with the ground that is required to trigger motion of the rover relative to the ground. Under such circumstances, hopping is one of the mobility solutions. We present a new locomotion system, the hopter platform, which is adapted to these challenges on Solar System bodies having a gravity field lower than on Earth. The hopter is a robust, versatile and highly manoeuvrable platform based on simple mechanical concepts that accurately jumps to distances of metres to tens of metres and more, depending on the gravity field of the studied body. Its low mass of 10 kg (including up to 3 kg of miniaturised payload), makes it possible to simultaneously launch several hopters to work as a fractionated explorer at a very competitive cost. After reviewing the payload that may be placed onboard hopters, we illustrate the scientific capabilities of hopters and hopter networks in performing basic geologic observations at distinct study sites in a variety of geological environments, obtaining data along steep geological cross sections, surveying geophysical anomalies in the subsurface, prospecting resources, monitoring micro environments, meteorological events, and geodetic deformation, or characterizing dust activity on Mars, the Moon, and Phobos.

  • 327.
    Narayan, Krishna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre. Elf Lab.
    Fabrication and characterization of nano/micrometer glass channels with UV lithography2017Independent thesis Advanced level (degree of Master (One Year)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    In this project, fabrication and characterization of nano/microfluidic channels on borosilicate glass substrate were carried out using a Photo/Ultraviolet (UV) lithography method, which has applications in single-cell analysis. In our single-cell analysis glass system, the bacterial cells will be made to sit in the micrometer channels and also the sub-micron size channels around 300 nm is aspired so it helps in passing the fluid to the outlet hole while holding the cells back. This system will help in the microscopic analysis of the bacterial cell growth over generations. A multi-layer mask approach is used to pattern the etch masks on a glass for the consecutive Isotropic wet etching of the glass substrate. Isotropic wet etching is utilized to transfer the patterned structures from a metal mask to the glass and also to under etch the differently sized spacing pitches (area separating nano/microfluidic channels in our design) to obtain sub-micron channel dimensions. Many test structures were designed on the photomask to optimize during the fabrication process with combinations of differently sized channels with differently sized spacing pitches ranging from 300 nm to 300 µm dimensions. In order to obtain this sub-micron sized channels on glass using a UV lithography technique is a challenging task, so the initial aim was to use the designed spacing pitches present between the channels as a platform to isotopically etch and create an under etched space width size in sub-micrometer. But we were able to obtain channel structure in sub-micron scale directly by optimizing multiple steps of the fabrication process. Characterization of the nano/microfluidic channels was done with the help of Optical microscopy and Dektak profilometer to measure the width, depth and uniformity of the structures during the optimization of the lithography process and scanning electron microscope (SEM) images were taken to analyze the channel dimensions and to get images of the fabricated channels.  

  • 328. Ngoc, Trinh Minh
    et al.
    Duy, Nguyen Van
    Hung, Chu Manh
    Hoa, Nguyen Duc
    Trung, Nguyen Ngoc
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hieu, Nguyen Van
    Ultralow power consumption gas sensor based on a self- heated nanojunction of SnO2 nanowires+2018In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 63, p. 36323-36330Article in journal (Refereed)
    Abstract [en]

    The long duration of a working device with a limited battery capacity requires gas sensors with low power consumption. A self-heated gas sensor is a highly promising candidate to satisfy this requirement. In this study, two gas sensors with sparse and dense SnO2 nanowire (NW) networks were investigated under the Joule heating effect at the nanojunction. Results showed that the local heating nanojunction was effective for NO2 sensing but generally not for reduction gases. At 1 W, the sparse NW sensor showed a good sensing performance to the NO2 gas. The dense SnO2 NW network required a high-power supply for gas-sensitive activation, but was suitable for reduction gases. A power of approximately 500 W was also needed for a fast recovery time. Notably, the dense NW sensor can response to ethanol and H2S gases. Results also showed that the self-heated sensors were simple in design and reproducible in terms of the fabrication process.

  • 329.
    Ngoc, Trinh Minh
    et al.
    International Training Institute for Materials Science, Hanoi University of Science and Technology.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hung, Chu Manh
    International Training Institute for Materials Science, Hanoi University of Science and Technology.
    Trung, Nguyen Ngoc
    School of Engineering Physics, Hanoi University of Science and Technology, Vietnam.
    Duy, Nguyen Van
    International Training Institute for Materials Science, Hanoi University of Science and Technology.
    H2S Sensing Characteristics of Self-heated Ag-coated SnO2 nanowires2017In: Proceeding of the 12th Asian Conference on Chemical Sensors (ACCS2017), Hanoi, 2017, p. 350-353Conference paper (Other academic)
    Abstract [en]

    The H2S gas sensing characterization of gas sensors based on the SnO2 nanowires network has been reported by several research groups. However, the self-heated gas sensor using Ag-coated SnO2 nanowires network for sensing H2S was investigated the first times. In this study, we will report on the effected of density SnO2 nanowires network on H2S sensitivity. The SnO2 nanowires network density can be controlled bythe distance between sensor electrodes. After SnO2 nanowires decorated with Ag, the results showt hat the H2S gas sensing properties depend on the density of the SnO2 nanowires network. Asthe density of SnO2 nanowires network increases, the response of sensors decreases. Thesensor can operate at as low power as 2 mW to H2S gas concentration of 0.25 ppm. The responseand recovery times of sensor are about 200 s. Moreover, working at low operating power gives us the benefit of energy saving as well as the elongation of lifetime.

  • 330.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Bejhed, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Köhler, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thermally regulated valve for minute flows2007In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 25, no 4, p. 686-691Article in journal (Refereed)
    Abstract [en]

    In this work, a gas valve using a microstructured silicon valve lid and a stainless steel valve seat clamped axially together in an aluminum cylinder is investigated. The difference in coefficient of thermal expansion of these components makes the valve open and close on a temperature change. A simple model accounting for elastic deformation of the system’s components is proposed to facilitate design of the valve. By means of a helium leak detector, a typical increase in flow rate from 1.0×10−8 to 1.0×10−4 sccs gaseous helium under a pressure of up to 10 bars was observed upon the increase of temperature from 12 to around 98 °C, after a single breaking-in. Plastic deformation of the valve seat as a consequence of an imprint of the microstructured valve lid and contaminating particles was studied. Microscopy confirmed a tolerance for particles of up to a few micrometers in diameter. Larger particles were found to be a possible cause of failure.

  • 331.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Bejhed, Johan
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Experimental Studies of Sealing Mechanism of a Dismountable Microsystem‑to‑Macropart Fluidic Connector for High Pressure and a Wide Range of Temperature2010In: Advances in Mechanical Engineering, ISSN 1687-8132, E-ISSN 1687-8140, Vol. 2010, article id 712587Article in journal (Refereed)
    Abstract [en]

    As fluidic microelectromechanical devices are developing and often attached to, or embedded in, large, complex and expensive systems, the issues of modularity, maintenance and subsystem replacement arise. In this work, a robust silicon connector suitable for high-pressure applications – likely with harsh fluids – in the temperature range of +100 to –100°C is demonstrated and tested together with a stainless steel nipple representing a simple and typical macropart. With a micromachined circular membrane equipped with a 5 μm high ridge, this connector is able to maintain a leak rate below 2.0´10-8 scc/s of gaseous helium with a pressure of up to 9.7 bar. Degradation of the sealing performance on reassembly is associated with the indentation of the ridge. However, the ridge makes the sealing interface less sensitive to particles in comparison with a flat reference. Most evaluation is made through so called heat-until-leak tests conducted to determine the maximum working temperature and the sealing mechanism of the connector. A couple of these are followed by cryogenic testing. The effect of thermal mismatch of the components is discussed and utilized as an early warning mechanism.

  • 332.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Bejhed, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Williams, Kirk
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Jonsson, Kerstin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Kratz, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Köhler, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Lang, Martin
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Micropropulsion systems research and manufacture in Sweden2003In: Proceedings of the 4th Round Table on Micro/Nano Technology for Space, ESTEC, Noordwijk, The Netherlands, ESTEC/ESA , 2003, p. 476-485Conference paper (Refereed)
    Abstract [en]

    Micropropulsion for spacecraft is an enabling technology for many future missions, and may increase the performance and drastically reduce the mass required for advanced propulsion systems. The Swedish activities in micropropulsion at The Angstrom Space Technology Centre (ASTC) are outlined. The research targets two major issues: the development of system parts, and the research into integration techniques and strategies. This paper collects a multitude of devices relevant to the micropropulsion system design, together with representative functional demonstrations.

    The items are mainly intended for chemical micropropulsion systems or fuel-feed systems for electric propulsion. In particular, gas handling devices, sensors, and actuators are presented. These include silicon nozzles, thin film heaters, suspended microcoil heaters, proportional piezoelectric valves, proportional and isolation valves using phase-change material, thermal throttle flow-regulators, high-pressure regulators, 3D-particle filters, and sensors for strain, pressure, flow, and thrust. Moreover, integration techniques and interface structures are presented, for example low-temperature plasma-assisted silicon wafer bonding, multiwafer bonding, thin film soldering, hermetic electric through-wafer via connections, and multiconnector through-wafer vias.

    Emphasis is on how these items are designed to allow for system integration in a multiwafer silicon stack, comprising a complete micropropulsion system. In this manner, all items form a parts collection available to the system design. This strategy is exemplified by three micropropulsion systems researched at the ASTC.

    First, the cold/hot gas micropropulsion system is suitable for small spacecraft or when the demands on stability and pointing precision are extreme. The system performance depends strongly on the use of gas flow control. The complete gas handling system of four independent thrusters is integrated in the assembly of four structured silicon wafers. Each independent thruster contains a proportional valve, sensors for pressure, temperature, and thrust feedback, a converging-diverging micronozzle, and a suspended microcoil heater. The mass of the system is below 60 g. In total, this will provide the spacecraft with a safe, clean, low-powered, redundant, and flexible system for three-axis stabilization and attitude control.

    Second, a Xenon feed system for ion propulsion is heavily miniaturized using microsystems technology. Basically, a micromachined high-pressure regulator receives the gas from the storage, and the flow is further modulated by a thermally controlled flow restrictor. The flow restrictor microsystem comprises narrow ducts, thin film heaters, suspended parts for heat management, and flow sensors. Hereby, the amount of xenon required by the electric propulsion systems can be promptly delivered. The complete system mass is estimated to 150g.

    Third, within the EU IST program, the ASTC participates in the development of a micro-pyrotechnic actuator system (Micropyros), suitable for short-duration space propulsion. The Micropyros integrate a full matrix of minute solid combustion rocket engines into panels situated on the spacecraft hull. The thrusters can be individually ignited, and each deliver thrust in the millinewton range. The ASTC focuses on the integration of the propulsion part by low-temperature bonding, and the characterization of the complete system.

  • 333.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Jonsson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Edqvist, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sundqvist, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kratz, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Heavily Miniaturized Submersible – A Terrestrial Kickoff2008In: Heavily Miniaturized Submersible – A Terrestrial Kickoff, 2008, p. S14-01Conference paper (Refereed)
    Abstract [en]

    The vision of exploring extraterrestrial water findings employing a remotely operated submersible, as proposed by JPL/NASA for the investigation of the possible ocean underneath the frozen crust of Jupiter’s moon Europa, is now taking a step further into fulfilment. The Ångström Space Technology Centre has developed a sophisticated vehicle concept based on microtechnology for most of the navigational systems and payload systems. This enables a high function density, and a compact vehicle with a diameter of 50 mm and length of 200 mm, i.e. an overall size allowing the vehicle to be deployed through a borehole like that typical for arctic drilling.

    Here, the system architecture of the vehicle complying with the requirements on manoeuvrability, operational functions, and mission objectives is presented. In short, the vehicle in the first version will operate in deep and narrow waters, and will be equipped with a camera, sonar imaging system, an electronic tongue for chemical sampling, and a Conductivity-Temperature-Depth (CTD) sensor. Although the vehicle will be given certain autonomy in later versions, the first edition will rely on remote manual guidance. Commands for this, as well as power download, and data upload will be communicated through an optic fibre.

    The objective of this contribution is to present, for the first time, the status of the project including, briefly, the first results from miniaturized sonar, the vehicle bus design, and the design, realization and testing of the propulsion and attitude control systems differing in manoeuvrability, weight/volume, redundancy and efficiency.

  • 334.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Köhler, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ångström Space Technology Centre, ÅSTC.
    The merits of cold gas micropropulsion in state-of-the-art space missions2002Conference paper (Refereed)
    Abstract [en]

    Cold gas micropropulsion is a sound choice for space missions that require extreme stabilisation, pointing precision or contamination-free operation. The use of forces in the micronewton range for spacecraft operations has been identified as a mission-critical item in several demanding space systems currently under development.

    Cold gas micropropulsion systems share merits with traditional cold gas systems in being simple in design, clean, safe, and robust. They do not generate net charge to the spacecraft, and typically operate on low-power. The minute size is suitable not only for inclusion on high-performance nanosatellites but also for high-demanding future space missions of larger sizes.

    By using differently sized nozzles in parallel systems the dynamic range of a cold gas micropropulsion system can be quite wide (e.g. 0 – 10 mN), while the smallest nozzle pair can deliver thrust of zero to 0.5 or 1 mN using continuously proportional gas flow control systems.

    The leakage is turned into an advantage enabling the system for continuous drag compensation. In this manner, the propellant mass efficiency can be many times as higher than that in a conventional cold gas propulsion system using ON-OFF-control.

    The analysis in this work shows that cold gas micropropulsion has emerged as a high-performance propulsion principle for future state-of-the-art space missions. These systems enable spacecraft with extreme demands on stability, cleanliness and precision, without compromising the performance or scientific return of the mission.

  • 335.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tailoring the properties of a magnetic tunnel junction to be used as a magnetic field sensor2011In: Conf. on solid state physics and materials VII (SPMS 2011), Ho Chi Minh, 7-9 November 2011, 2011Conference paper (Refereed)
    Abstract [en]

    A magnetic tunnel junction (MTJ) can be used as an effective magnetic field sensor thank to its high magnetoresistance ratio. To be used as a magnetic field sensor in different applications, the possibility of tuning the performance of the MTJ is important. Different means of tuning, such as voltage and magnetic field biasing, can be used. In this work, an external magnetic field from a permanent magnet was used to bias the sensing layer of a MTJ along its hard axis, and the effect of the biasing on the sensitivity, detection limit, and hysteresis of the MTJ was investigated. The experiments showed that the hysteresis of the MTJ languished away at a certain applied magnetic field. Moreover, the sensitivity and noise level decreased, whereas the detection limit increased with increasing bias field strength. The motivation of this experiment is not only to find a power- and cost-effective method of tuning the MTJ, but also to study what happens with the sensing layer, and with electron transport within the MTJ when an external magnetic field is applied.

  • 336.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Material- and fabrication-governed performance of a tunnelling magnetometer2010Conference paper (Refereed)
  • 337.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Material- and fabrication-governed performance of a tunnelling magnetometer2010In: Advances in Natural Sciences: Nanoscience and Nanotechnology, ISSN 2043-6254, E-ISSN 2043-6262, Vol. 1, no 4, p. 045006-Article in journal (Refereed)
    Abstract [en]

    Miniaturization of sensitive magnetic sensors for nano- and picosatellites has come to the point where the traditional sensors with magnetic coils soon can be replaced. Thin film technology offers the possibility of making extremely small magnetic field sensors that employ the effect of anisotropic, giant and tunneling magnetoresistance (AMR, GMR and TMR). In this paper, the development status of sensors based on microelectromechanical systems technology (MEMS), starting from a TMR layer structure is presented. The sensors have been successfully fabricated and integrated onto an electronic circuit designed for space application. The system as a whole, and the sensors in particular, have not only been characterized with respect to sensitivity, resolution, and noise level, but also to launch vibration and space radiation. The sensor performance and limitations are strongly dependent on the deposited materials, sensor design, and fabrication process. Since the sensor elements are small and sensitive (with lateral dimensions of some tens of micrometres, and resolution of 100 pT at frequencies of MHz), they are also promising for other MEMS applications.

  • 338.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Material- and fabrication-governedperformance of a tunnellingmagnetometer2010In: Material- and fabrication-governedperformance of a tunnellingmagnetometer, 2010Conference paper (Refereed)
    Abstract [en]

    Miniaturization of sensitive magnetic sensors for nano- and picosatellites has come to the point where the traditional sensors with magnetic coils soon can be replaced. Thin film technology offers the possibility of making extremely small magnetic field sensors that employ the effect of anisotropic, giant and tunneling magnetoresistance (AMR, GMR and TMR). In this paper, the development status of sensors based on microelectromechanical systems technology (MEMS), starting from a TMR layer structure is presented. The sensors have been successfully fabricated and integrated onto an electronic circuit designed for space application. The system as a whole, and the sensors in particular, have not only been haracterized with respect to sensitivity, resolution, and noise level, but also to launch vibration and space radiation. The sensor performance and limitations are strongly dependent on the deposited materials, sensor design, and fabrication process. Since the sensor elements are small and sensitive (with lateral dimensions of some tens of micrometres, and resolution of 100 pT at frequencies of MHz), they are also promising for other MEMS applications

  • 339.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Quy, Chu ThiHanoi University of Science and Technology (HUST), Hanoi, VIETNAM.Hoa, Nguyen DucHanoi University of Science and Technology (HUST), Hanoi, VIETNAM.Hieu, Nguyen VanHanoi University of Science and Technology (HUST), Hanoi, VIETNAM.
    A design of high performance gas sensor array withdiscrete islands of Au catalyst for increasing of ZnO nanowire junctions2013Conference proceedings (editor) (Refereed)
    Abstract [en]

    In this study, an effective design for growth of ZnO nanowires directly on gas sensor chips is introduced. The design utilizes the dendrite islands of Au catalyst deposited between and on the Pt electrodes for the nanowires to grow on instead of a continuous seed layer or Au film. This lead to an increase of the nanowirenanowire junctions in the devices, as well as a reduction of the leak current that would occur through the mentioned alternative seed layer; resulting in a higher sensitivity. The results showed that the developed gas sensors could be used for monitoring of NO2 at low concentration.

  • 340.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Quy, Chu Thi
    Hanoi University of Science and Technology.
    Hoa, Nguyen Duc
    Hanoi University of Science and Technology.
    Lam, Nguyen The
    Hanoi Pedagogical University No 2, Vinhphuc, Viet Nam.
    Duy, Nguyen Van
    Hanoi University of Science and Technology.
    Quang, Vu Van
    Hanoi University of Science and Technology.
    Hieu, Nguyen Van
    Hanoi University of Science and Technology.
    Controllable growth of ZnO nanowires grown on discrete islands of Au catalyst for realization of planar-type micro gas sensors2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 193, p. 888-894Article in journal (Refereed)
    Abstract [en]

    The proper engineering design of gas sensors and the controlled synthesis of sensing materials for the high-performance detection of toxic gas are very important in the fabrication of handheld devices. In this study, an effective design for gas sensor chips is developed to control the formation of grown ZnO nanowires (NWs).The design utilizes the dendrite islands of Au catalyst deposited on and between Pt electrodes of a planar-type micro gas sensor so that NWs can grow on instead of a continuous Au seed layer. This method results in an increase of NW-NW junctions on the device and also eliminates current leakage through the seed layer, which results in a higher sensitivity. The results show that the developed gas-sensing devices could be used to monitor NO2 at moderate temperature (~250 °C) and/or ethanol at a high temperature (~400 °C).

  • 341.
    Nguyen, Hugo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Material considerations and fabrication methods for rapid prototyping of MTJs2009In: Konf. on solid state physics and materials VI, I-007, 2009, 2009, p. 9-Conference paper (Other academic)
  • 342.
    Nguyen, Thi Quynh Hoa
    et al.
    School of Engineering and Technology, Vinh University, Vietnam.
    Phan, Duy Tung
    School of Engineering and Technology, Vinh University, Vietnam.
    Nguyen, Duc Dung
    School of Engineering and Technology, Vinh University, Vietnam.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tran, Sy Tuan
    School of Engineering and Technology, Vinh University, Vietnam;Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam.
    Numerical study of a wide incident angle- and polarisation-insensitive microwave metamaterial absorber based on a symmetric flower structure2019In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 9, no 6, article id 065318Article in journal (Refereed)
    Abstract [en]

    In this study, we propose a wide incident angle- and polarisation-insensitive metamaterial absorber covered with structures comprising a metallic flower shape layer, a dielectric layer and a metallic ground plane. The influences of the structural parameters on the absorptivity are investigated numerically. The proposed absorber exhibits polarisation insensitivity as the number of symmetric petals of a flower shape reaches as high as 4, 6 and 8. Particularly, the absorber based on 8 petals shows an absorptivity of above 90% for wide incident angles up to 70° under transverse electric and transverse magnetic polarisations. The physical mechanism of these observations is clarified by investigating the electric, power loss density and induced current distributions, which is also supported by the retrieved constitutive electromagnetic parameters. That is, the absorption phenomenon is considerably affected by magnetic resonance. By modifying the petals into hollow shapes, the absorber becomes effective in confining the magnetic resonance and can thus minimise the resonant frequency variation to 0.22% without affecting the absorption performance. In comparison with other reported metamaterial absorbers, our design shows considerable practical feasibility in terms of resonant frequency stability, wide incident angle and polarisation insensitivity, thereby making it suitable for various applications in microwave frequency region.

  • 343.
    Nguyen Van, Toan
    et al.
    Hanoi University of Science and Technology.
    Nguyen Viet, Chien
    Hanoi University of Science and Technology.
    Nguyen Van, Duy
    Hanoi University of Science and Technology.
    Hoang Si, Hong
    Hanoi University of Science and Technology.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nguyen Duc, Hoa
    Hanoi University of Science and Technology.
    Nguyen Van, Hieu
    Hanoi University of Science and Technology.
    Fabrication of highly sensitive and selective H2 gas sensor based on SnO2 thin film sensitized with microsized Pd islands2016In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 301, p. 433-442Article in journal (Refereed)
    Abstract [en]

    Ultrasensitive and selective hydrogen gas sensor is vital component in safe use of hydrogen that requires a detection and alarm of leakage. Herein, we fabricated a H2 sensing devices by adopting a simple design of planar–type structure sensor in which the heater, electrode, and sensing layer were patterned on the front side of a silicon wafer. The SnO2 thin film–based sensors that were sensitized with microsized Pd islands were fabricated at a wafer–scale by using a sputtering system combined with micro–electronic techniques. The thicknesses of SnO2 thin film and microsized Pd islands were optimized to maximize the sensing performance of the devices. The optimized sensor could be used for monitoring hydrogen gas at low concentrations of 25–250 ppm, with a linear dependence to H2 concentration and a fast response and recovery time. The sensor also showed excellent selectivity for monitoring H2 among other gases, such as CO, NH3, and LPG, and satisfactory characteristics for ensuring safety in handling hydrogen. The hydrogen sensing characteristics of the sensors sensitized with Pt and Au islands were also studied to clarify the sensing mechanisms.

  • 344.
    Nikolajeff, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Diamond optics - An emerging technology for demanding applications2004Conference paper (Refereed)
  • 345.
    Nordh, Nicki
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Development of a cell cultureplatform in PDMS: Microfluidic systems for in vitro productionof platelets2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To be able to effectively study blood platelets in different environments adevelopment of an in vitro model of a microfluidic system for plateletproduction was started. The purpose of this thesis was to fabricate systemsand then characterize them and visualize the flow. The system consists of twochannels, one in the middle and the other one enclosing it. They are connectedthrough pores where Megakaryocytes can protrude through and produce platelets.The designs were produced in PDMS. This was done by first transfer the designsas structures onto a silicon wafer through UV lithography. The wafer served asa mould for casting PDMS that later was bonded to glass. The systems were thenstudied with three different methods. Computer simulations, flow tests andultimately tests with cells. From the results new designs were made andfabricated. The new designs were then tested the same ways as the first ones.The systems can most probably produce platelets with some optimisation of thetest parameters. No definite results were gathered to prove plateletproduction. Different flow speeds were tested and the flow profile atdifferent flow rates was visualised. The full capability of the new designscould not be fully studied due to unforeseen debris of PDMS clogging thechannels. A few things need to be done to achieve better results and establishfor sure if this method of producing platelets is possible. This thesis is agood ground for future work to stand on.

  • 346.
    Näsström, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Fagerqvist, Therese
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences.
    Barbu, Mikael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Kasrayan, Alex
    Bioarctic Neuroscience AB, Stockholm.
    Ekberg, Monica
    Bioarctic Neuroscience AB, Stockholm.
    Lannfelt, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Ingelsson, Martin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Bergström, Joakim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    The lipid peroxidation products 4-oxo-2-nonenal and 4-hydroxy-2-nonenal promote the formation of α-synuclein oligomers with distinct biochemical, morphological, and functional properties2011In: Free Radical Biology & Medicine, ISSN 0891-5849, E-ISSN 1873-4596, Vol. 50, no 3, p. 428-437Article in journal (Refereed)
    Abstract [en]

    Oxidative stress has been implicated in the etiology of neurodegenerative disorders with alpha-synuclein pathology. Lipid peroxidation products such as 4-oxo-2-nonenal (ONE) and 4-hydroxy-2-nonenal (HNE) can covalently modify and structurally alter proteins. Herein, we have characterized ONE- or HNE-induced alpha-synuclein oligomers. Our results demonstrate that both oligomers are rich in beta-sheet structure and have a molecular weight of about 2000 kDa. Atomic force microscopy analysis revealed that ONE-induced alpha-synuclein oligomers were relatively amorphous, with a diameter of 40-80 nm and a height of 4-8 nm. In contrast, the HNE-induced alpha-synuclein oligomers had a protofibril-like morphology with a width of 100-200 nm and a height of 2-4 nm. Furthermore, neither oligomer type polymerized into amyloid-like fibrils despite prolonged incubation. Although more SDS and urea stable, because of a higher degree of cross-linking, ONE-induced alpha-synuclein oligomers were less compact and more sensitive to proteinase K treatment. Finally, both ONE- and HNE-induced alpha-synuclein oligomers were cytotoxic when added exogenously to a neuroblastoma cell line, but HNE-induced alpha-synuclein oligomers were taken up by the cells to a significantly higher degree. Despite nearly identical chemical structures, ONE and HNE induce the formation of off-pathway alpha-synuclein oligomers with distinct biochemical, morphological, and functional properties.

  • 347.
    Näsström, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Wahlberg, Therese
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Barbu, Mikael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Silva, V.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Lannfelt, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Ingelsson, Martin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Bergström, Joakim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Morphological and functional differences of aldehyde-induced alpha-synuclein oligomers2010In: Amyloid - Journal of Protein Folding Disorders, 2010, Vol. 17, p. 93-94Conference paper (Refereed)
  • 348.
    Näsström, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Wahlberg, Therese
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Lannfelt, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Ingelsson, Martin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    Bergström, Joakim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Geriatrics.
    The lipid peroxidation metabolite 4-oxo-2-nonenal cross-links alpha-synuclein causing rapid formation of stable oligomers2009In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 378, no 4, p. 872-876Article in journal (Refereed)
    Abstract [en]

    Recently, the aldehyde 4-oxo-2-nonenal (ONE) was identified as a product of lipid peroxidation and found to be an effective protein modifier. In this in vitro study we investigated structural implications of the interaction between ONE and alpha-synuclein, a protein which forms intraneuronal inclusions in neurodegenerative disorders such as Parkinson's disease and dementia with Lewy bodies. Our results demonstrate that ONE induced an almost complete conversion of monomeric alpha-synuclein into 40-80 nm wide and 6-8 nm high soluble beta-sheet-rich oligomers with a molecular weight of approximately 2000 kDa. Furthermore, the ONE-induced alpha-synuclein oligomers displayed a high stability and were not sensitive to treatment with sodium dodecyl sulfate, indicating that ONE stabilized the oligomers by cross-linking individual alpha-synuclein molecules. Despite prolonged incubation the oligomers did not continue to aggregate into a fibrillar state, thus suggesting that these alpha-synuclein species were not on a fibrillogenic pathway.

  • 349.
    Ogden, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-Pressure Microfluidics2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, some fundamentals and possible applications of high-pressure microfluidics have been explored. Furthermore, handling fluids at high pressures has been addressed, specifically by creating and characterizing strong microvalves and pumps.

    A variety of microstructuring techniques was used to realize these microfluidic devices, e.g., etching, lithography, and bonding. To be able to handle high pressures, the valves and pumps need to be strong. This necessitates a strong actuator material. In this thesis, the material of choice is paraffin wax.

    A new way of latching paraffin-actuated microvalves into either closed or open position has been developed, using the low thermal conductivity of paraffin to create large thermal gradients within a microactuator. This allows for long open and closed times without power consumption.

    In addition, three types of paraffin-actuated pumps are presented: A peristaltic high-pressure pump with integrated temperature control, a microdispensing pump with high repeatability, and a pump system with two pumps working with an offset to reduce flow irregularities. Furthermore, the fundamental behavior of paraffin as a microactuator material has been explored by finite element modeling.

    One possibility that arises with high-pressure microfluidics, is the utilization of supercritical fluids for different applications. The unique combination of material properties found in supercritical fluids yields them interesting applications in, e.g., extraction and cleaning. In an attempt to understand the microfluidic behavior of supercritical carbon dioxide, the two-phase flow, with liquid water as the second phase, in a microchannel has been studied and mapped with respect to both flow regime and droplet behavior at a bi-furcating outlet.

    List of papers
    1. A Latchable Valve for High-Pressure Microfluidics
    Open this publication in new window or tab >>A Latchable Valve for High-Pressure Microfluidics
    2010 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 19, no 2, p. 396-401Article in journal (Refereed) Published
    Abstract [en]

    In this paper, the strongest yet latchable valve in subcubic-centimeter size for microfluidic applications is presented. The device has an integrated actuator cavity consisting of three segments filled with paraffin, each operated by a separate heater. At one of the segments, a membrane valve head is deflected by the expansion of the resistively melted paraffin to close against its valve seat. Different heating sequences provide a latched closed or opened valve. The maximum pressure before any leakage occurred was 2.5 MPa. The leak pressure is found to be progressively dependent on the clamping pressure applied. The valve has an opening and closing time of 7 and 1 s, respectively. At an applied pressure of 0.3 MPa, the closed valve needs to be reactivated every 100 min to remain leakage free, leading to an average power consumption of 4.5 mW.

    Keywords
    Fluid flow control, microactuators, steel, valves
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-126963 (URN)10.1109/JMEMS.2010.2041749 (DOI)000276257700019 ()
    Available from: 2010-07-01 Created: 2010-07-01 Last updated: 2017-12-12Bibliographically approved
    2. High-pressure stainless steel active membrane microvalves
    Open this publication in new window or tab >>High-pressure stainless steel active membrane microvalves
    Show others...
    2011 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 21, no 7, p. 075010-Article in journal (Refereed) Published
    Abstract [en]

    In this work, high-pressure membrane microvalves have been designed, manufactured andevaluated. The valves were able to withstand back-pressures of 200 bar with a response timeof less than 0.6 s. These stainless steel valves, manufactured with back-end batch production,utilize the large volume expansion coupled to the solid–liquid phase transition in paraffin wax.When membrane materials were evaluated, parylene coated stainless steel was found to be thebest choice as compared to polydimethylsiloxane and polyimide. Also, the influence of theorifice placement and diameter is included in this work. If the orifice is placed too close to therim of the membrane, the valve can stay sealed even after turning the power off, and the valvewill not open until the pressure in the system is released. The developed steel valves, evaluatedfor both water and air, provide excellent properties in terms of mechanical stability, ease offabrication, and low cost. Possible applications include sampling at high pressures, chemicalmicroreactors, high performance liquid chromatography, pneumatics, and hydraulics.

    Keywords
    stainless steel, high pressure microvalve, paraffin
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-131007 (URN)10.1088/0960-1317/21/7/075010 (DOI)000291935000024 ()
    Available from: 2010-09-20 Created: 2010-09-20 Last updated: 2017-12-12Bibliographically approved
    3. A latchable high-pressure thermohydraulic valve actuator
    Open this publication in new window or tab >>A latchable high-pressure thermohydraulic valve actuator
    2012 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 188, p. 292-297Article in journal (Refereed) Published
    Abstract [en]

    This work presents a latchable thermohydraulic microactuator for use in high-pressure valves, e.g. for oceanic sampling in missions of long duration. Mounted on a miniature submersible, it can be used in confined spaces to explore previously unreachable environments. However, the device can be used in any high-pressure application where long duration open and/or closed valve states are required, and power consumption is an issue. The actuator is fabricated using standard batch-processes as photochemical machining, wet etching and photolithography. The actuation and latching mechanisms are both thermohydraulic, using solid-to-liquid phase transition of paraffin for actuation and of a low melting point alloy for latching. Focus of this work is on the endurance of the actuator to facilitate a bistable valve. The actuator managed to keep a deflected position for almost 50 hours to the load equivalent to 1.8 MPa applied pressure, after which the experiment was aborted. No pressure dependence was discovered in the latching losses, i.e. the difference in deflection before and after the actuator is powered off. Furthermore, the effect of intermixing of paraffin and the low melting point alloy was evaluated.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Fluid control, Bistable, Steel, Actuator, Paraffin, Low melting point alloy
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171755 (URN)10.1016/j.sna.2011.11.027 (DOI)000312692500039 ()
    Conference
    The 16th International Conference on Solid-State Sensors, Actuators and Microsystems, 5-9 June, 2011, Beijing, CHINA
    Available from: 2012-03-27 Created: 2012-03-27 Last updated: 2017-12-07Bibliographically approved
    4. Acoustically enriching, large-depth aquatic sampler
    Open this publication in new window or tab >>Acoustically enriching, large-depth aquatic sampler
    Show others...
    2012 (English)In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, no 9, p. 1619-1628Article in journal (Refereed) Published
    Abstract [en]

    In marine biology, it is useful to collect water samples when exploring the distribution and diversity of microbial communities in underwater environments. In order to provide, e.g., a miniaturized submersible explorer with the capability of collecting microorganisms, a compact sample enrichment system has been developed. The sampler is 30 mm long, 15 mm wide, and just a few millimetres thick. Integrated in a multilayer steel, polyimide and glass construction is a microfluidic channel with piezoelectric transducers, where microorganism and particle samples are collected and enriched, using acoustic radiation forces for gentle and labelless trapping. High-pressure, latchable valves, using paraffin as the actuation material, at each end of the microfluidic channel keep the collected sample pristine. A funnel structure raised above the surface of the device directs water into the microfluidic channel as the vehicle propels itself or when there is a flow across its hull. The valves proved leak proof to a pressure of 2.1 MPa for 19 hours and momentary pressures of 12.5 MPa, corresponding to an ocean depth of more than 1200 metres. By reactivating the latching mechanism, small leakages through the valves could be remedied, which could thus increase the leak-less operational time. Fluorescent particles, 1.9 µm in diameter, were successfully trapped in the microfluidic channel at flow rates up to 15 ml min-1, corresponding to an 18.5 cm s-1 external flow rate of the sampler. In addition, liquid-suspended GFP-marked yeast cells were successfully trapped.

    Keywords
    Acoustic, microorganism, enriching, trap, valve, paraffin, sampler, marine, actuator
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171734 (URN)10.1039/C2LC00025C (DOI)000302368200009 ()
    Projects
    Deeper Access, Deeper Understanding (DADU)
    Available from: 2012-03-26 Created: 2012-03-26 Last updated: 2017-12-07Bibliographically approved
    5. Modeling and Analysis of a Phase Change Material Thermohydraulic Membrane Microactuator
    Open this publication in new window or tab >>Modeling and Analysis of a Phase Change Material Thermohydraulic Membrane Microactuator
    2013 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 22, no 1, p. 186-194Article in journal (Refereed) Published
    Abstract [en]

    Presented in this paper is a finite-element-method-based model for phase change material actuators, modeling the active material as a fluid as opposed to a solid. This enables the model to better conform to localized loads and offering the opportunity to follow material movement in enclosed volumes. Modeling, simulation, and analysis of an electrothermally activated paraffin microactuator have been conducted. The paraffin microactuator used for the analysis in this study exploits the large volumetric expansion of paraffin upon melting, which, combined with its low compressibility in the liquid state, allows for high hydraulic pressures to be generated. The purpose of this study is to supply a geometry-independent model of such a microactuator through the implementation of a fluid model rather than a solid one, which has been utilized in previous studies. Numerical simulations are conducted at different frequencies of the heating source and for different geometries of the microactuator. The results are compared with the empirical data obtained on a close to identical paraffin microactuator, which clearly show the advantages of a fluid model instead of a solid-state approximation.

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-186116 (URN)10.1109/JMEMS.2012.2222866 (DOI)000314726900026 ()
    Funder
    Swedish Research Council
    Available from: 2012-11-28 Created: 2012-11-28 Last updated: 2017-12-07Bibliographically approved
    6. High-Pressure Peristaltic Membrane Micropump With Temperature Control
    Open this publication in new window or tab >>High-Pressure Peristaltic Membrane Micropump With Temperature Control
    Show others...
    2010 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 19, no 6, p. 1462-1469Article in journal (Refereed) Published
    Abstract [en]

    A high-pressure peristaltic membrane micropump, which is capable of pumping against a back pressure of 150 bar, has been evaluated. The main focus was to maintain the flow characteristics also at high back pressures. The pump was manufactured by fusion bonding of parylene-coated stainless-steel stencils. A large-volume expansion connected to the solid-to-liquid phase transition in paraffin was used to move 10 µm stainless-steel membranes. The pump was evaluated by using two different driving schemes, a four-phase cycle and a six-phase cycle. With the six-phase cycle, a constant flow rate of 0.4 µL min-1 was achieved over an interval ranging from atmospheric pressure to 130 bar. At lower back pressures, the more energy efficient four-phase cycle achieved slightly higher flow rates than the six-phase cycle. However, it required higher driving voltage at high back pressures. Since the pump is thermally activated, a temperature sensor was integrated to control the melting and solidification of paraffin, implying capability of increasing the performance of the pump. With a thickness of only 1 mm as well as a simple and robust design, the micropump is well suited for integration in analytical systems. The high pressures managed are in the region needed for, e.g., high-performance liquid chromatography systems.

    Keywords
    High back pressure, integrated temperature sensor, paraffin actuator, peristaltic micropump, pressure-independent flow, stainless-steel membrane
    National Category
    Materials Engineering
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-139213 (URN)10.1109/JMEMS.2010.2076784 (DOI)000284875400020 ()
    Available from: 2010-12-22 Created: 2010-12-22 Last updated: 2017-12-11Bibliographically approved
    7. Microdispenser with continuous flow and selectable target volume for microfluidic high-pressure applications
    Open this publication in new window or tab >>Microdispenser with continuous flow and selectable target volume for microfluidic high-pressure applications
    2014 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 23, no 2, p. 452-458Article in journal (Refereed) Published
    Abstract [en]

    This paper presents a reusable microdispenser intended for continuous flow dispensing of variable and controlled volumes of liquid against high back-pressures. The microdispenser consists of two active valves and a dispenser chamber, all actuated by the volume change associated with the solid-to-liquid phase transition of paraffin wax. It is fabricated using stainless steel sheets, a flexible printed circuit board, and a polyimide membrane. All are covered with Parylene C for insulation and fusion bonding at assembly. A finite element method (FEM) model of the paraffin actuator is used to predict the resulting flow characteristics. The results show dispensing of well-defined volumes of 350 and 540 nL, with a good repeatability between dispensing sequences, as well as reproducibility between devices. In addition, the flow characteristics show no back-pressure dependence of the dispensed flow in the interval 0.5--2.0 MPa. The FEM model can be used to predict the flow characteristics qualitatively

    Keywords
    High pressure, liquid chromatography, MEMS, microdispenser, micropump, phase change material
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-208855 (URN)10.1109/JMEMS.2013.2279976 (DOI)000334526200022 ()
    Funder
    Swedish Research CouncilVINNOVA, 29461-1ÅForsk (Ångpanneföreningen's Foundation for Research and Development)
    Available from: 2013-10-09 Created: 2013-10-09 Last updated: 2017-12-06Bibliographically approved
    8. On-chip pump system for high-pressure microfluidic applications
    Open this publication in new window or tab >>On-chip pump system for high-pressure microfluidic applications
    Show others...
    2013 (English)Conference paper, Poster (with or without abstract) (Refereed)
    Abstract [en]

    This paper presents a micropump system with four integrated paraffin actuated pumps: Two mobile phase pumps and two sample injector pumps. The mobile phase pumps are evaluated by their ability to deliver a stable, low-ripple flow to be used in chip-based high performance liquid chromatography. It is shown that the two mobile phase pumps can be driven in combined operation with an induced offset to significantly lower flow fluctuations.

    Keywords
    High Pressure, Paraffin, Phase Change Material, Microelectromechanical Systems
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-204725 (URN)
    Conference
    µTAS 2013
    Funder
    Swedish Research Council
    Available from: 2013-08-09 Created: 2013-08-09 Last updated: 2015-09-07
    9. Fluid behavior of supercritical carbon dioxide with water in a double-Y-channel microfluidic chip
    Open this publication in new window or tab >>Fluid behavior of supercritical carbon dioxide with water in a double-Y-channel microfluidic chip
    Show others...
    2014 (English)In: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 17, no 6, p. 1105-1112Article in journal (Refereed) Published
    Abstract [en]

    The use of supercritical carbon dioxide (scCO2) as an apolar solvent has been known for decades. It offers a greener approach than, e.g., hexane or chloroform, when such solvents are needed. The use of scCO2 in microsystems, however, has only recently started to attract attention. In microfluidics, the flow characteristics need to be known to be able to successfully design such components and systems. As supercritical fluids exhibit the exciting combination of low viscosity, high density, and high diffusion rates, the fluidic behavior is not directly transferrable from aqueous systems. In this paper, three flow regimes in the scCO2–liquid water two-phase microfluidic system have been mapped. The effect of both total flow rate and relative flow rate on the flow regime is evaluated. Furthermore, the droplet dynamics at the bifurcating exit channel are analyzed at different flow rates. Due to the low viscosity of scCO2, segmented flows were observed even at fairly high flow rates. Furthermore, the carbon dioxide droplet behavior exhibited a clear dependence on both flow rate and droplet length.

    Keywords
    Two-phase flow, segmented flow, parallel flow, wavy flow droplet dynamics
    National Category
    Fluid Mechanics and Acoustics
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-207265 (URN)10.1007/s10404-014-1399-6 (DOI)000345389900014 ()
    Funder
    Swedish Research Council
    Available from: 2013-10-10 Created: 2013-09-11 Last updated: 2017-12-06Bibliographically approved
    10. Review on miniaturized paraffin phase change actuators, valves, and pumps
    Open this publication in new window or tab >>Review on miniaturized paraffin phase change actuators, valves, and pumps
    Show others...
    2014 (English)In: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 17, no 1, p. 53-71Article, review/survey (Refereed) Published
    Abstract [en]

    During the last fifteen years, miniaturised paraffin actuation has evolved through the need of a simple actuation principle, still able to deliver large strokes and high actuation forces at small scales. This is achieved by the large and rather incompressible volume expansion associated with the solid-to-liquid phase transition of paraffin. The common approach has been to encapsulate the paraffin by a stiff surrounding that directs the volume expansion towards a flexible membrane, which deflects in a directed stroke. However, a number of alternative methods have also been used in the literature. The most common applications to this date have been switches, positioning actuators, and microfluidic valves and pumps. This review will treat the historical background, as well as the fundamentals in paraffin actuation, including material properties of paraffin. Besides reviewing the three major groups of paraffin actuator applications; actuators, valves, and pumps, the modelling done on paraffin actuation will be explored. Furthermore, a section focusing on fabrication of paraffin microactuators is also included. The review ends with conclusions and outlook of the field, identifying unexplored potential of paraffin actuation.

    National Category
    Applied Mechanics
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-208904 (URN)10.1007/s10404-013-1289-3 (DOI)000338835300002 ()
    Available from: 2013-11-30 Created: 2013-10-10 Last updated: 2017-12-06Bibliographically approved
  • 350.
    Ogden, Sam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Bodén, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Do-Quang, Minh
    KTH.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Amberg, Gustav
    KTH.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fluid behavior of supercritical carbon dioxide with water in a double-Y-channel microfluidic chip2014In: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 17, no 6, p. 1105-1112Article in journal (Refereed)
    Abstract [en]

    The use of supercritical carbon dioxide (scCO2) as an apolar solvent has been known for decades. It offers a greener approach than, e.g., hexane or chloroform, when such solvents are needed. The use of scCO2 in microsystems, however, has only recently started to attract attention. In microfluidics, the flow characteristics need to be known to be able to successfully design such components and systems. As supercritical fluids exhibit the exciting combination of low viscosity, high density, and high diffusion rates, the fluidic behavior is not directly transferrable from aqueous systems. In this paper, three flow regimes in the scCO2–liquid water two-phase microfluidic system have been mapped. The effect of both total flow rate and relative flow rate on the flow regime is evaluated. Furthermore, the droplet dynamics at the bifurcating exit channel are analyzed at different flow rates. Due to the low viscosity of scCO2, segmented flows were observed even at fairly high flow rates. Furthermore, the carbon dioxide droplet behavior exhibited a clear dependence on both flow rate and droplet length.

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