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  • 1.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ek, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hedman, Ludvig
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sehlstedt, Viktor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Stocklassa, Jesper
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Snögren, Pär
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Pettersson, Victor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Larsson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Vizuete, Olivier
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 1, article id 015018Article in journal (Refereed)
    Abstract [en]

    High-pressure microfluidics offers fast analyses of thermodynamic parameters for compressed process solvents. However, microfluidic platforms handling highly compressible supercritical CO2 are difficult to control, and on-chip sensing would offer added control of the devices. Therefore, there is a need to integrate sensors into highly pressure tolerant glass chips. In this paper, thin film Pt sensors were embedded in shallow etched trenches in a glass wafer that was bonded with another glass wafer having microfluidic channels. The devices having sensors integrated into the flow channels sustained pressures up to 220 bar, typical for the operation of supercritical CO2. No leakage from the devices could be found. Integrated temperature sensors were capable of measuring local decompression cooling effects and integrated calorimetric sensors measured flow velocities over the range 0.5-13.8 mm/s. By this, a better control of high-pressure microfluidic platforms has been achieved.

  • 2.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fracture strength of glass chips for high-pressure microfluidics2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, article id 095009Article in journal (Refereed)
    Abstract [en]

    High-pressure microfluidics exposes new areas in chemistry. In this paper, the reliability of transparent borosilicate glass chips is investigated. Two designs of circular cavities are used for fracture strength tests, either 1.6 mm wide with rounded corners to the fluid inlets, or 2.0 mm wide with sharp inlet corners. Two kinds of tests are done, either short-term,e.g. pressurization to fracture at room temperature, or long-term, with fracture at constant pressurization for up to one week, in the temperature region 11–125 °C. The speed of crack fronts is measured using a high-speed camera. Results show fracture stresses in the range of 129 and 254 MPa for short-term measurements. Long-term measurements conclude the presences of a temperature and stress dependent delayed fracture. For a reliability ofone week at 11–38 °C, a pressure limit is found at the lower end of the short-term measurements, or 15% lower than the average. At 80 °C, this pressure limit is 45% lower. Crack speeds are measured to be 10−5 m s-1 during short-term fracture. These measurements are comparable with estimations based on slow crack growth and show that the growth affects the reliability of glass chips. This effect is strongly affected by high temperatures, thus lowers the operating window of high-pressure glass microfluidic devices.

  • 3.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure glass microfluidics for supercritical CO2 with aqueous solutions2016Conference paper (Refereed)
    Abstract [en]

    A microfluidic system is presented to investigate interactions between supercritical CO2 and H2O using high-pressure glass chips. The reliability of these chips at pressures necessary to sustain CO2 in the supercritical phase is dependent of both time and temperature. 130 bar can be kept at 38°C for more than a week. These systems can be used to investigate fluid interaction between supercritical CO2 and aqueous solutions by the addition of pH sensitive dye and high speed absorption light imagining, making it possible to demonstrate acidification is in a multiphase chip. By the addition of integrated temperature sensors, better control of the states of the fluids inside the chips can be achieved.

  • 4.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-Speed Imaging Of The ph Drop In Aqueous solutions In Contact With Supercritical Co2 Segments2016Conference paper (Other academic)
    Abstract [en]

    A high-speed imaging system based on light absorption of bromophenol blue (BPB) pH sensitivedye in a glass high-pressure microchip is used to study the instantaneous dynamics of a pH drop in anaqueous phase in contact with segments of subcritical (liquid) and supercritical CO2. The dynamics ofthe pH-drop has been studied and visualized, demonstrating acidification rates of up to 3.5 pH/s.

  • 5.
    Andersson, Martin
    et al.
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High Pressure Glass Devices For CO2 And H2O2016Conference paper (Other academic)
    Abstract [en]

    A microfluidic system is presented to investigate interactions between supercritical CO2 and H2O using high-pressure glass chips. The reliability of these chips at pressures necessary to sustain CO2 in the supercritical phase is dependent of both time and temperature. 130 bar can be kept at 38°C for more than a week. These systems can be used to create parallel flow streams used to investigate reaction dynamics by the addition of pH sensitive dyes. 

  • 6.
    Andersson, Martin
    et al.
    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.
    Svensson, karolina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Södergren, Simon
    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.
    Microfluidics for High-Pressure Analyses2018In: 12th Micronano System Workshop (MSW 2018, May 14-15, 2018, Espoo, Finland) / [ed] Samilu Fransilla, 2018, p. 8-8Conference paper (Refereed)
    Abstract [en]

    When using appropriate materials and microfabrication techniques, the small dimensionsand mechanical stability of microstructured devices allow for processes at high pressureswithout loss in safety. The largest area of applications has been demonstrated in chemistry,where extraction, synthesis and analyses often excel at high densities and high temperatures.These two parameters are accessible through high pressures. Capillary chemistry has beenused since long but, just like in low-pressure applications, there are several advantages in usingmicrofluidic platforms for control of reactions, catalysis, mixing and separation. For example,planar isothermal set-ups, large local variations in geometries, dense form factors, small deadvolumes and precisely positioned microstructures.In analytical systems, we are studying high-pressure components and microsystems forsampling, sample preparation, analyses and fractionation. We will present what drives ourresearch and development: Our experimental set-up with high-pressure pumps, high-speedcamera, sensors, valves, piston-chambers, backpressure regulators, cooling table, etc. How wehave built capability in pumping and valving by the use of stainless steel and paraffinactuation. How we are making high pressure silicon-glass and glass-glass chips with integratedelectrical thin film sensors, using printed circuit boards to ease handling of the chips andintegrating modules. A set of relevant publications are listed below.

  • 7.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mårtensson, Gustaf
    EMSL, MC2, Chalmers University of Technology, Göteborg, Sweden.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flowing and pressurizing a solid-liquid two phase monodispersed fluid with high solid content in a transparent microfluidic high-pressure chip2017Conference paper (Refereed)
  • 8.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mårtensson, Gustav
    Mycronic AB, Täby.; Chalmers Univ Technol, MC2, EMSL, Gothenburg.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flowing and pressurizing a solid-liquid two phase monodispersed fluid with high solid content in a transparent microfluidic high-pressure chip2017In: 28TH MICROMECHANICS AND MICROSYSTEMS EUROPE WORKSHOP, IOP PUBLISHING LTD , 2017, article id UNSP 012010Conference paper (Refereed)
    Abstract [en]

    Handling highly concentrated solid-liquid two-phase fluids in microfluidics is challenging. In this paper, we present the first studies of flowing solder paste with a high solid content in a transparent high-pressure tolerant glass chip, thereby increasing the understanding of how multiphase liquids with high density difference between the phases behave in small channels (840 mu m in diameter). The system, including a custom made high-pressure, low resistance, interface, was continuously operated at pressures up to of 6 MPa and devices where shown to have pressure tolerance up to 17 MPa. During flow through the chip, the packing density of the solder balls displayed inhomogeneity over the channel where chains of solder balls in contact with each other were formed together with voids. These in-homogeneities persisted along the channel during flow. The flow rate of the paste through the chip oscillated between 63 to 350 mu m/s when pumping at constant volume rate of 30 mu l/min. When a pressure of 2 MPa was applied, the volume of the solder paste particle segment decreased 1.6%, and 0.1% was elastically recovered when the pressure was released. It is concluded that this transparent microfluidic high-pressure glass chip with the special developed interface is suitable for flow studies of solder paste with a high solid content.

  • 9.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rodriguez-Meizoso, Irene
    Turner, Charlotta
    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.
    Dynamic pH determination at high pressure of aqueous additive mixtures in contact with dense CO22018In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 136, p. 95-101Article in journal (Refereed)
    Abstract [en]

    A system consisting of a high-pressure tolerant microfluidic glass chip, high-speed absorbance imaging, and image processing has been developed to study rapid dynamic events like pH change in a multiphase flow. The system gives both kinetic and quantitative equilibrated information. By tracking the interactions of aqueous additive mixtures and liquid CO2, at 80 bar and 24 °C, under flow, measurement at a given P, T condition is done in 0.25 s. The acidification rate to steady state was found to be mass transport limited, occurring in less than 1 s. For 30 mM of the additives ammonium acetate and ammonium formate, equilibrium pH of 4.5 and 4.1, respectively, was seen. These additives are of key importance in common mobile phases used in SFC.

  • 10.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Stocklassa, Jesper
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Control Systems For Gas-Expanded Liquids In Microreactors2017Conference paper (Refereed)
  • 11.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Svensson, Karolina
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A microfluidic control board for high-pressure flow, composition, and relative permittivity2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 21, p. 12601-12608Article in journal (Refereed)
    Abstract [en]

    Flow control is central to microfluidics and chromatography. With decreasing dimensions and high pressures, precise fluid flows are often needed. In this paper, a high-pressure flow control system is presented, allowing for the miniaturization of chromatographic systems and the increased performance of microfluidic setups by controlling flow, composition and relative permittivity of two-component flows with CO2. The system consists of four chips: two flow actuator chips, one mixing chip and one relative permittivity sensor. The actuator chips, throttling the flow, required no moving parts as they instead relied on internal heaters to change the fluid resistance. This allows for flow control using miniaturized fluid delivery systems containing only a single pump or pressure source. Mobile phase gradients between 49% to 74% methanol in CO2 were demonstrated. Depending on how the actuator chips were dimensioned, the position of this range could be set for different method-specific needs. With the microfluidic control board, both flow and composition could be controlled from constant pressure sources, drift could be removed, and variations in composition could be lowered by 84%, resulting in microflows of CO2 and methanol with a variation in the composition of 0.30%.

  • 12.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wilson, Anton
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows2019In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 165-172Article in journal (Refereed)
    Abstract [en]

    Binary CO2-alcohol mixtures, such as CO2-expanded liquids (CXLs), are promising green solvents for reaching higher performance in flow chemistry and separation processing. However, their compressibility and high working pressure makes handling challenging. These mixtures allow for a tuneable polarity but, to do so, requires precise flow control. Here, a high-pressure tolerant microfluidic system containing a relative permittivity sensor and a mixing chip is used to actively regulate the relative permittivity of these fluids and indirectly—composition. The sensor is a fluid-filled plate capacitor created using embedded 3D-structured thin films and has a linearity of 0.9999, a sensitivity of 4.88 pF per unit of relative permittivity, and a precision within 0.6% for a sampling volume of 0.3 μL. Composition and relative permittivity of CO2-ethanol mixtures were measured at 82 bar and 21 °C during flow. By flow and dielectric models, this relationship was found to be described by the pure components and a quadratic mixing rule with an interaction parameter, kij, of -0.63 ± 0.02. Microflows with a relative permittivity of 1.7–21.4 were generated, and using the models, this was found to correspond to compositions of 6–90 mol % ethanol in CO2. With the sensor, a closed loop control system was realised and CO2-ethanol flows were tuned to setpoints of the relative permittivity in 30 s.

  • 13.
    Khaji, Zahra
    et al.
    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.
    Barbade, Dhananjay
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Palmer, Kristoffer
    SSC Nanospace.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Endurance and Failure of an Alumina-based Monopropellant Microthruster with Integrated Heater, Catalytic Bed and Temperature Sensors2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 5, p. 1-11, article id 055011Article in journal (Refereed)
    Abstract [en]

    Monopropellant ceramic microthrusters with an integrated heater, catalytic bed and two temperature sensors, but of various designs, were manufactured by milling a fluidic channel and chamber, and a nozzle, and screen printing platinum patterns on green tapes of alumina that were stacked and laminated before sintering. In order to increase the surface area of the catalytic bed, the platinum paste was mixed with a sacrificial paste that disappeared during sintering, to leave behind a porous and rough layer. As an early development level in manufacturing robust and high-temperature tolerant microthrusters, the influence of design on the temperature gradients and dry temperature tolerance of the devices was studied. On average, the small reaction chambers showed a more than 1.5 times higher dry temperature tolerance (in centigrade) compared to devices with larger chambers, independent of the heater and device size. However, for a given temperature, big devices consumed on average 2.9 times more power than the small ones. It was also found that over the same area and under the same heating conditions, devices with small chambers were subjected to approximately 40% smaller temperature differences. A pressure test done on two small devices with small chambers revealed that pressures of at least 26.3 bar could be tolerated. Above this pressure, the interfaces failed but the devices were not damaged. To investigate the cooling effect of the micropropellant, the endurance of a full thruster was also studied under wet testing where it was fed with 31 wt.% hydrogen peroxide. The thruster demonstrated complete evaporation and/or full decomposition at a power above 3.7 W for a propellant flow of 50 mu l min(-1). At this power, the catalytic bed locally reached a temperature of 147 degrees C. The component was successfully heated to an operating temperature of 307 degrees C, where it cracked. Under these firing conditions, and assuming complete decomposition, calculations give a thrust and specific impulse of 0.96 mN and 106 s, respectively. In the case of evaporation, the corresponding values are calculated to be 0.84 mN and 92 s.

  • 14.
    Khaji, Zahra
    et al.
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Manufacturing and characterization of a ceramic single-use microvalve2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, article id 095002Article in journal (Refereed)
    Abstract [en]

    We present the manufacturing and characterization of a ceramic single-use microvalve withthe potential to be integrated in lab-on-a-chip devices, and forsee its utilization in space andother demanding applications. A 3 mm diameter membrane was used as the flow barrier, andthe opening mechanism was based on cracking the membrane by inducing thermal stresses onit with fast and localized resistive heating.

    Four manufacturing schemes based on high-temperature co-fired ceramic technology werestudied. Three designs for the integrated heaters and two thicknesses of 40 and 120 μmfor the membranes were considered, and the heat distribution over their membranes, therequired heating energies, their opening mode, and the flows admitted through were compared.Furthermore, the effect of applying +1 and −1 bar pressure difference on the membraneduring cracking was investigated. Thick membranes demonstrated unpromising results forlow-pressure applications since the heating either resulted in microcracks or cracking of thewhole chip. Because of the higher pressure tolerance of the thick membranes, the designwith microcracks can be considered for high-pressure applications where flow is facilitatedanyway. Thin membranes, on the other hand, showed different opening sizes depending onheater design and, consequently, heat distribution over the membranes, from microcracks toholes with sizes of 3–100% of the membrane area. For all the designs, applying +1 bar overpressure contributed to bigger openings, whereas −1 bar pressure difference only did so forone of the designs, resulting in smaller openings for the other two. The energy required forbreaking these membranes was a few hundred mJ with no significant dependence on designand applied pressure. The maximum sustainable pressure of the valve for the current designand thin membranes was 7 bar.

  • 15.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Swedish National Defence College.
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Design and fabrication of a miniaturized combustor with integrated oxygen storage and release element2014In: 25th Micromechanics and Microsystems Europe workshop  (MME 2014),2014, P19 (4 pp), 2014Conference paper (Refereed)
    Abstract [en]

    A miniature combustor for converting organic samples into CO2 with application in carbon isotopic measurements of small samples has been manufactured and evaluated. The combustor was made by machining and laminating High-Temperature Co-fired Ceramic (HTCC) 99.99% alumina green tapes and screen printing platinum conductors on them. The device has a built-in heater and a temperature sensor made of platinum, which were co-sintered with the ceramic. A metal oxide (copper oxide) oxygen supply was added to the combustor after sintering by in-situ electroplating of copper on the heater pattern followed by thermal oxidation. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Thermal Gravimetric Analysis (TGA) were used to study electroplating, oxidation and the oxide decompo-sition processes.

  • 16.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish National Defence College.
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Investigation of the storage and release of oxygen in a Cu-Pt element of a high-temperature microcombustor2014In: The 14th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications(PowerMEMS 2014), Institute of Physics (IOP), 2014Conference paper (Refereed)
    Abstract [en]

    A miniature combustor for converting organic samples into CO2 with application in carbon isotopic measurements has been manufactured and evaluated. The combustor was made of High-Temperature Co-fired Ceramic (HTCC) alumina green tapes. The device has a built-in screen printed heater and a temperature sensor made of platinum, co-sintered with the ceramic. A copper oxide oxygen supply was added to the combustor after sintering by in-situ electroplating of copper on the heater pattern followed by thermal oxidation. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Thermal Gravimetric Analysis (TGA) were used to study electroplating, oxidation and the oxide reduction processes. The temperature sensor was calibrated by use of a thermocouple. It demonstrates a temperature coefficient resistance of 4.66×10−3/°C between 32 and 660 °C. The heat characterization was done up to 1000 °C by using IR thermography, and the results were compared with the data from the temperature sensor. Combustion of starch confirmed the feasibility of using copper oxide as the source of oxygen of combustion.

  • 17.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Swedish National Defence College.
    Klintberg, Lena
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Manufacturing and characterization of a ceramic microcombustor with integrated oxygen storage and release element2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 104006Article in journal (Refereed)
    Abstract [en]

    A microscale ceramic high-temperature combustor with a built-in temperature sensor and source of oxygen has been designed, manufactured and characterized. The successful in situ electroplating and oxidation of copper, and the use of copper oxide as the source of oxygen were demonstrated. It was shown that residual stresses from electroplating, copper oxidation and oxide decomposition did not cause much deformation of the substrate but influenced mainly the integrity and adhesion of the metal films. The process had influence on the electrical resistances, however. Calibration of the temperature sensor and correlation with IR thermography up to 1000°C revealed a nearly linear sensor behavior. Demonstration of combustion in a vacuum chamber proved that no combustion had occurred before release of oxygen from the metal oxide resource.

  • 18.
    Khaji, Zhara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, Peter
    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.
    Thornell, Greger
    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.
    Extending Microsensor Technology to Very High Temperatures2014Conference paper (Other academic)
  • 19.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Karlsson, M
    Stenmark, Lars
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    A large stroke, high force paraffin phase transition actuator2002In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 96, no 2-3, p. 189-195Article in journal (Refereed)
    Abstract [en]

    An actuator that uses the volume expansion related to the solid-to-liquid phase transition of paraffin wax has been fabricated and evaluated. The actuator consists of a ring-shaped paraffin cavity confined by two joint silicon diaphragms with rigid centers. When the paraffin is melted, the resulting hydrostatic pressure deflects the joined rigid centers in one direction only. The magnitude of the deflection is primarily a function of the geometrical relation between the two diaphragms, giving the opportunity to tailor the behavior of the actuator in a large range. Conventional IC-processing techniques have been used to fabricate a prototype with a width of 68 mm and a thickness of 825 μm. The prototype attained a maximum deflection of ca. 90 μm. Loaded with 3 N it still exhibits a deflection of ca. 75 μm. The device can be used as a thermal switch.

  • 20.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Karlsson, M
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    A thermally activated paraffin-based actuator for gas-flow control in a satellite electrical propulsion system2003In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 105, no 3, p. 237-246Article in journal (Refereed)
    Abstract [en]

    Microstructured silicon devices consisting of three inflatable paraffin-filled, corrugated caddies suspended in springs to minimize thermal losses have been fabricated and evaluated with a valve application in mind. The large volume expansion associated with the thermally induced solid-to-liquid phase transition of paraffin is used to activate the caddies’ diaphragms. Theses components all with a thickness of 600 μm and a diameter of 39 mm, but with three different corrugations, have been fabricated with deep reactive etching (DRIE). Whereas the corrugated diaphragms could endure a deflection larger than 50 μm, only strokes of 15 μm on each side were attained when the components were activated. Together with the valve seats proposed, the investigated devices have a potential in electrical propulsion systems for satellites.

  • 21.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Lindeberg, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Sodium hypochlorite as a developer for heavy ion tracks in polyimide2001In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 184, no 4, p. 536-543Article in journal (Refereed)
    Abstract [en]

    he developing and etching of heavy ion tracks in polyimide with sodium hypochlorite have been studied to gain control over the parameters that affect the etch result. The shape of the resulting pores is a function of both alkalinity and hypochlorite content of the solution. Sodium hypochlorite decomposes during etching, and the rate constant has been determined as a function of the alkalinity at 62 °C. Polished cross-sections have been examined to determine the pore shape, and this method has shown to be a straightforward way to characterise the pores. Decreasing the alkalinity gives more cylindrical pores, but increases the decomposition rate of the hypochlorite solution and decreases the etch rate.

  • 22.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Svedberg, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Nikolajeff, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Fabrication of a paraffin actuator using hot embossing of polycarbonate2003In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 103, no 3, p. 307-316Article in journal (Refereed)
    Abstract [en]

    In this paper a fabrication process for integrating paraffin-actuated structures in polycarbonate is outlined. A paraffin-actuated membrane with a diameter of 2.5 mm, where the volume expansion of 10–15% associated with the solid-to-liquid phase transition of paraffin is utilized, has been fabricated and evaluated. Microstructures fabricated in silicon have via an electroplated nickel mould been replicated in polycarbonate by hot embossing and the resulting structures have been sealed by thermal bonding. The bonding strength was measured by a pressurizing test, and the polycarbonate surfaces were characterized with electron spectroscopy for chemical analysis (ESCA). It was found that the bond strength increased when an oxygen plasma treatment was used prior to bonding. ESCA measurements showed a corresponding increase in oxygen content on the plasma treated surfaces. This procedure also improved the wetting properties. The contact angle between paraffin and polycarbonate decreased from 10° after embossing to about 5° after plasma treatment. The fabricated actuator had a total thickness of 1 mm and the membrane deflected about 140 μm when heating the actuator above the melting point of paraffin. Paraffin wax actuators are possible to integrate in plastic structures making them promising candidates in applications such as disposable microfluidic systems where inexpensive and robust valves and pumps are needed.

  • 23.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    A thermal microactuator made by partial impregnation of polyimide with paraffin2002In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 12, no 6, p. 849-854Article in journal (Refereed)
    Abstract [en]

    We have fabricated and tested thermal, paraffin-impregnated polyimide actuators, utilizing the large volume increase associated with the solid-to-liquid phase transition of paraffin. In the bimorph-like device, the top layer was made porous by ion track technology. Stochastically distributed pores of various lengths (95, 70, 45 and 20 µm) and various lateral coverages (5–45%) were filled with paraffin by liquid substitution or from vacuum, and sealed with epoxy. Actuators, 125 µm thick, 35 mm long and 7 mm wide, have been characterized with respect to tip deflection and load-carrying capacity with one end rigidly clamped. Loaded with 0.6 g or about ten times their own weight at their free end, about 50% of the maximum stroke (17 mm) was still attained.

  • 24.
    Klintberg, Lena
    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.
    Som man frågar får man svar: studenter formulerar frågor och väljer lärstrategi2015In: 5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Uppsala, 2015Conference paper (Refereed)
    Abstract [sv]

    Blooms taxonomi kategoriserar olika lärstrategierefter komplexitetsgrad. Nybörjare är faktafokuserade eftersomdet är mer krävande att analysera, bedöma och värderakunskaper. Valet av lärstrategi är situationsberoende ochfaktorer som motivation och nyfikenhet leder ofta till ett merkomplext angreppssätt. För att undersöka vad civilingenjörsstudentersom läser näst sista året själva spontant väljerför lärstrategier, fick 43 studenter läsa in ett antal artiklar somett moment i kursen Mikro- och nanoteknik I. Därefter ombadsde formulera frågor på materialet. I ett försök att aktivt påverkade lärstrategier som studenterna valde skulle frågorna bådeberöra sådant studenterna identifierade som värdefull kunskapsamt sådant artiklarna inte gav svar på men som de skulle viljaveta. Studenterna fick sedan klassificera frågorna enligt Bloomstaxonomi. För ett antal utvalda frågor jämfördes därefterklassificeringen med en som lärarkollegiet gjorde och resultatetblev att lärarna tenderade att ranka de enkla frågorna högre ochmer komplicerade frågor lägre jämfört med studenterna. I en uppföljningsstudie undersöktes om studenterna ansåg attuppgiften att själv få formulera frågor gett dem bättreförståelsen och fått dem att fundera mer över materialet jämfört med om de fått instuderingsuppgifter. Resultatet visar att praktiskt taget alla studenter spontantställt minst en fråga som de kategoriserat ibland de högsta komplexitetsnivåerna och som tillsammans täcker de inkomna frågorna de aspekter som lärarkollegiet anser är viktigt imaterialet. Vissa artiklar visade sig stimulera till frågor med högre komplexitet och det fanns ett tydligt samband som visadeatt mer komplexa frågor ställdes då svaren inte fanns imaterialet. Hela 68% av studenterna bedömde att metoden att själva få formulera frågor på materialet givit dem en bättre förståelse jämfört med om de fått färdiga frågor att besvara efter inläsningen. Frågorna visade sig också ge värdefull insikt i vad studenterna funderar på och är nyfikna att veta mer om, t ex aspekter rörande miljö, hälsa och ekonomi.

  • 25.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Viberg, Pernilla
    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.
    Förmedling av komplexa begrepp i multidisciplinär kurs på avancerad niv2013Conference paper (Refereed)
    Abstract [sv]

    Vid undervisning på avancerad nivå i en multidisciplinär kurs används och behandlas vanligtvis komplexa begrepp från flera olika ämnesområden. Vid samläsning över olika program, skiljer sig studenternas förkunskaper åt även om studenterna från de olika programmen formellt uppfyller förkunskapskraven. Detta inverkar på studenternas förmåga att tillgodogöra sig kursens innehåll.

    En studie har gjorts på en kurs i mikro- och nanoteknik, som ges under 4:e året på flera olika civilingenjörsprogram. Med anledning av de identifierade skillnaderna, har en undersökning av tidigare studenters erfarenhet av kursen gjorts. Dessutom har de blivande studenternas förkunskaper inventerats och jämförts med de begrepp som används i kursen.

    Resultatet visar att studenterna i kemiteknik i viss utsträckning förfördelats även om skillnaderna är små.

    16% av studenterna som läst teknisk fysik med material­vetenskap (MV) når högsta betyg på kursen jämfört med 10% för studenterna i kemiteknik (KT), men i medelbetyg är det ingen signifikant skillnad mellan studentgrupperna. Vid rankning av påståendet ”Nya begrepp introducerades på ett bra och tydligt sätt” gav MV-studenterna 4,0 i medel medan KT studenterna gav 3,5 på skalan 1 (aldrig) till 5 (alltid). Syftet med denna undersökning är att, utifrån de identifierade skillnaderna, kunna hitta nya sätt att introducera och exemplifiera begreppen så att studentgrupperna får likvärdiga förutsättningar att tillgodogöra sig kursens innehåll.

  • 26.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of surface modifications and channel structure for microflows of supercritical carbon dioxide and water2016In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 107, p. 649-656Article in journal (Refereed)
    Abstract [en]

    Miniaturization offers a possibility to increase the performance and decrease the time scales of systems. Existing microsystems using supercritical CO2 mainly utilizes multiphase segmented flows. To allow for a broader toolbox for future systems, also parallel flows are useful which eases the separation of the different phases. Here, the effect of different surface coatings are studied for multiphase flows of scCO2 and H2O in flat microchannels, with and without a 4 μm high ridge guide, which allows for pinning of the fluid interface inside the 190 μm wide and 35 μm high channel. Three different surfaces with different wettings towards scCO2 and H2O are studied, where a surface terminated with a hydrocarbon-based silane was observed to be neutral in the H2O/scCO2 system, a surface terminated with a fluorocarbon-based silane was hydrophobic, and an uncoated glass surface was hydrophilic.

    Using two flow rates of 5:5 μl/min (CO2:H2O) and 6.5:3.5 μl/min (CO2:H2O), a parallel flow between scCO2 and H2O was observed for uncoated and flat channels where the H2O flow pushed the CO2 to the side, before the flows eventually breaks up into segments. With a ridge guide in the middle of the channel, the interface was pinned at half the channel width, although still breaking up into segments. The neutral hydrocarbon-based surface coating with approximately 90° contact angles resulted in evenly created segments without a ridge guide. Including a guide in the middle of the channel, a parallel flow was observed throughout the channel, although occasionally small CO2 segments entered the H2O outlet. Using the fluorocarbon-based silane resulted in an unstable segmented system with pressure fluctuations.

    Using surface modifications, an increased control can be achieved for either segmentation or parallel flow where a neutral surface is favored for a stable flow behavior. Together with a ridge guide, the fluid interface was pinned at the center. 

  • 27.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mannitol for High Temperature Phase Change Actuators2014Conference paper (Other academic)
    Abstract [en]

    To enable valves for hot water microsystems, the possibility of using the volume expansion of the phase transition from solid to liquid in mannitol for strong high temperature actuators was studied. From room temperature to 160°C, a linear expansion of 4% was measured, and the expansion at the phase transition from solid to liquid at 160°C to 180°C was measured to be 7%. Stainless steel structures with a stainless steel diaphragm was filled and repeatedly heated up to 180◦C while measuring the deflection of the diaphragm using a laser sensor. The height differences was measured to be 25 μm at 180°C.

    In combination with a fluidic system, the mannitol actuator should capable as a valve for hot water microsystems. 

  • 28.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rogeman, Niklas
    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.
    Amberg, Gustav
    KTH.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105001Article in journal (Refereed)
    Abstract [en]

    Supercritical carbon dioxide (scCO2) is often used to replace harmful solvents and can dissolve a wide range of organic compounds. With a favorable critical point at 31 °C and 7.4 MPa, reaching above the critical point for scCO2 is fairly accessible. Because of the compressible nature of scCO2 and the large changes of viscosity and density with temperature and pressure, there is a need to determine the behavior of scCO2 in microfluidic systems. Here, the influence of how parameters such as flow rate, temperature, pressure, and flow ratio affects the length of parallel flow of water and scCO2 and the length of the created CO2 segments are investigated and modeled using multivariate data analysis for a 10 mm long double-y channel. The parallel length and segment size were observed in the laminar regime around and above the critical point of CO2. The flow ratio between the two fluids together with the flow rate influenced both the parallel length and the segment sizes, and a higher pressure resulted in shorter parallel lengths. Regarding the segment length of CO2, longer segments were a result of a higher Weber number for H2O together with a higher temperature in the channel. 

  • 29.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, P.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Characterization of dielectric properties of polycrystalline aluminum nitride for high temperature wireless sensor nodes2013In: 13th International Conference on Micro And Nanotechnology for Power Generation and Energy Conversion Applications (Powermems 2013), 2013Conference paper (Refereed)
    Abstract [en]

    An aluminium nitride (AIN) passive resonance circuit intended for thermally matched high temperature wireless sensor nodes (WSN) was manufactured using thick-film technology. Characterization was done for temperatures up to 900 C in both a hot-chuck for frequencies below 5 MHz, and using wireless readings of resonating circuits at 15 MHz, 59 MHz, and 116 MHz. The substrate for the circuits was sintered polycrystalline AIN. Using a simplified model for the resonators where the main contribution of the frequency-shift was considered to come from a shift of the dielectric constant for these frequencies, the temperature dependency of the dielectric constant for AIN was found to decrease with increasing frequency up to 15 MHz. With an observed frequency shift of 0.04% at 15 MHz, and up to 0.56% at 59 MHz over a temperature range of 900 C, AIN looks as a promising material for integration of resonance circuits directly on the substrate.

  • 30.
    Lekholm, Ville
    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.
    Klintberg, Lena
    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.
    Investigation of a zirconia co-fired ceramic calorimetric microsensor for high-temperature flow measurements2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 6, article id 065014Article in journal (Refereed)
    Abstract [en]

    This paper describes the design, fabrication and characterization of a flow sensor for high-temperature, or otherwise aggressive, environments, like, e.g. the propulsion system of a small spacecraft. The sensor was fabricated using 8 mol% yttria stabilized zirconia (YSZ8) high-temperature co-fired ceramic (HTCC) tape and screen printed platinum paste. A calorimetric flow sensor design was used, with five 80 mu m wide conductors, separated by 160 mu m, in a 0.4 mm wide, 0.1 mm deep and 12.5 mm long flow channel. The central conductor was used as a heater for the sensor, and the two adjacent conductors were used to resistively measure the heat transferred from the heater by forced convection. The two outermost conductors were used to study the influence of an auxiliary heat source on the sensor. The resistances of the sensor conductors were measured using four-point connections, as the gas flow rate was slowly increased from 0 to 40 sccm, with different power supplied through the central heater, as well as with an upstream or downstream heater powered. In this study, the thermal and electrical integrability of microcomponents on the YSZ8 substrate was of particular interest and, hence, the influence of thermal and ionic conduction in the substrate was studied in detail. The effect of the ion conductivity of YSZ8 was studied by measuring the resistance of a platinum conductor and the resistance between two adjacent conductors on YSZ8, in a furnace at temperatures from 20 to 930 degrees C and by measuring the resistance with increasing current through a conductor. With this design, the influence of ion conductivity through the substrate became apparent above 700 degrees C. The sensitivity of the sensor was up to 1 m Omega sccm(-1) in a range of 0-10 sccm. The results show that the signal from the sensor is influenced by the integrated auxiliary heating conductors and that these auxiliary heaters provide a way to balance disturbing heat sources, e.g. thrusters or other electronics, in conjunction with the flow sensor.

  • 31.
    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%.

  • 32.
    Ogden, Sam
    et al.
    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.
    Thornell, Greger
    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.
    Bodén, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Review on miniaturized paraffin phase change actuators, valves, and pumps2014In: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 17, no 1, p. 53-71Article, review/survey (Refereed)
    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.

  • 33.
    Ohlin, Mathias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    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.
    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.
    In situ temperature monitoring during acoustophoresis using integrated thin film Pt temperature sensors2017Conference paper (Refereed)
  • 34.
    Ohlin, Mathias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    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.
    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.
    Internal temperature sensing in an acoustophoretic glass chip2017Conference paper (Refereed)
  • 35.
    Persson, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Khaji, Zahra
    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.
    Dynamic Behaviour and Conditioning Time of a Zirconia Flow Sensor for High-Temperature Applications2016In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 251, p. 59-65Article in journal (Refereed)
    Abstract [en]

    The temperature dependent ion conductivity of yttria stabilized zirconia (YSZ) can be used to create a miniaturized flow sensor using a calorimetric measurement scheme. Such a sensor is compatible with harsh environments, and can sustain temperatures of up to 1000 degrees C, although thermal crosstalk will limit its performance as the temperature rises. This paper investigates if the integration of thermal isolation in the form of sealed cavities can mitigate the detrimental effect of the thermal crosstalk, particularly by studying the conditioning time of the sensor to temperature changes. To this end, high temperature co-fired ceramic (HTCC) sensors were fabricated from tapes of 8 mol-% YSZ that were screen printed with platinum paste. Definition of channels and structures were made by milling the green tapes, and sacrificial inserts were placed in all cavities to give mechanical support during lamination and sintering. Cavities with widths of 240 mu m, 400 mu m and 560 mu m were investigated, and sensors without cavities were also made to serve as references. Additionally, two different positions of the sensor element with respect to the edge of the cavity (560 or 800 mu m) were investigated. The results showed that it was possible to improve the conditioning time of the sensor by up to five times by the use of isolating cavities, and that this improvement is translated into a reduction in rate-dependent hysteresis for measurements with long elapse times. The latter effect is most pronounced for the sensors with the largest cavities.

  • 36.
    Persson, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Lekholm, Ville
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A high-temperature calorimetric flow sensor employing ion conduction in zirconia2015In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 106, no 19, article id 194103Article in journal (Refereed)
  • 37.
    Sharma, Guniana
    et al.
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Viton-based fluoroelastomer microfluidics2011In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 21, no 2, p. 025016-025023Article in journal (Refereed)
    Abstract [en]

    Viton is an elastomer with low permeability and high chemical resistance. This paper presents the main characteristics and technical issues involved in fabricating Viton-based microfluidics by micromoulding, bonding and metallization. A PDMS (polydimethylsiloxane) mould is used to imprint the Viton compound in a curing step that is followed by a post-curing without the mould. Viton was fusion bonded, with high quality, to itself and to stainless steel when clamped together during a post-curing step. Having low permeability to hydrocarbon liquids, Viton is a well-suited elastomer for making paraffin membrane microactuators, as demonstrated here. These kinds of microactuators may find their applications in fluid handling with hydraulic oils, in vacuum systems or in reactors and analytical systems, where Viton comes in direct contact with fluids that would permeate or degrade other elastomers.

  • 38.
    Sharma, Guniana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Svensson, S
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ogden, Sam
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-pressure stainless steel active membrane microvalves2011In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 21, no 7, p. 075010-Article in journal (Refereed)
    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.

  • 39.
    Sharma, Gunjana
    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.
    Kolari, K
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Printed fluidic board platform for pressure induced cell migration studies2009In: Micromechanics Europe Workshop 2009, 2009, p. 1-3Conference paper (Refereed)
  • 40.
    Sharma, Gunjana
    et al.
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Imprinting and bonding of the fluoroelastomer Viton for microfluidics2010In: 14th Int. Conf. on Miniaturized Systems for Chemistry and Life Sciences, 2010, p. 548-550Conference paper (Refereed)
  • 41.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Försvarshögskolan/Swedish National Defence College.
    Berglund, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Söderberg, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Fabrication of Suspended All-Metal Sensor Elements in Ceramic Laminates2016In: Proc. of Micronano System Workshop 2016, Lund, Sweden, May 17-18, 2016, 2016Conference paper (Other academic)
    Abstract [en]

    To target a wide range of high-temperature applications [1-4], the Ångström Space Technology Centre has added High-Temperature Co-fired Ceramics, HTTC, technology to its repertoire. Usually, this technology follows a processing scheme where thin sheets of green-body ceramics are metallized through screen printing and structured by embossing, punching or milling, before they are laminated and sintered to form components. A limitation with this, is the difficulty of realizing freely suspended metal structures, which is a disadvantage in, e.g., the fabrication of calorimetric sensors or electric field probes. In this work, the embedding of platinum wires in HTCC is explored experimentally, and demonstrated for use in pressure and plasma I-V sensing.

  • 42.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Försvarshögskolan/Swedish National Defence College.
    Khaji, Zahra Atena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    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.
    Klintberg, Lena
    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.
    Thermomechanical stability and integrability of an embedded ceramic antenna with an integrated sensor element for wireless reading in harsh environments2013In: Journal of Physics: Conference Series: Volume 476 / [ed] Paul Mitcheson and Steve Beeby, 2013Conference paper (Refereed)
    Abstract [en]

    This paper reports on the design, manufacturing and evaluation of a small, wirelessly powered and read resonating antenna circuit with an integrated pressure sensor. The work aims at developing miniature devices suitable for harsh environments, where high temperature prevents the use of conventional, silicon-based microdevices. Here, the device is made of alumina with platinum as conducting material. Ceramic green tapes were structured using high-precision milling, metallized using screen printing, and subsequently laminated to form stacks before they were sintered. The device's frequency shift as a function of temperature was studied up to 900°C. The contributions to the shift both from the thermomechanical deformation of the device at large, and from the integrated and, so far, self-pressurized sensor were sorted out. A total frequency shift of 3200 ppm was observed for the pressure sensor for heating over the whole range. Negligible levels of thermally induced radius of curvature were observed. With three-point bending, a frequency shift of 180 ppm was possible to induce with a curvature of radius of 220 m at a 10 N load. The results indicate that a robust pressure sensor node, which can register pressure changes of a few bars at 900°C and wirelessly transmit the signal, is viable.

  • 43.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Swedish Def Univ, Dept Mil Sci, S-11428 Stockholm, Sweden..
    Khaji, Zahra
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ceramic Pressure Sensor for High Temperatures – Investigation of the Effect of Metallizationon on Read Range2017In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 17, no 8, p. 2411-2421Article in journal (Refereed)
    Abstract [en]

    A study on the relationship between circuit metallization, made by double-layer screen printing of platinum and electroplating of silver on top of platinum, and its impact on practical read range of ceramic LC resonators for high-temperature pressure measurements is presented. Also included is the first realization of membranes by draping a graphite insert with ceramic green body sheets. As a quality factor circuit reference, two-port microstrip meander devices were positively evaluated and to study interdiffusion between silver and platinum, test samples were annealed at 500 degrees C, 700 degrees C, and 900 degrees C for 4, 36, 72, and 96 h. The LC resonators were fabricated with both metallization methods, and the practical read range at room temperature was evaluated. Pressure-sensitive membranes were characterized for pressures up to 2.5 bar at room temperature, 500 degrees C and up to 900 degrees C. Samples electroplated with silver exhibited performance equal to or better than double-layer platinum samples for up to 60 h at 500 degrees C, 20 h at 700 degrees C, and for 1 h at 900 degrees C, which was correlated with the degree of interdiffusion as determined from cross-sectional analysis. The LC resonator samples with double-layer platinum exhibited a read range of 61 mm, and the samples with platinum and silver exhibited a read range of 59 mm. The lowest sheet resistance, and, thereby, the highest read range of 86 mm, was obtained with a silver electroplated LC resonator sample after 36 h of annealing at 500 degrees C.

  • 44.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish National Defence College.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thermomechanical behaviour and pressure sensing of ceramic wireless devices for high-temperature environments2014Conference paper (Refereed)
    Abstract [en]

    This paper reports on the design, fabrication and thermomechanical characterization of wirelessceramic devices, one with an integrated pressure sensor element. The project aims at developingmicrosystems for sensing in harsh environments where conventional electronic devices are restrained.Here, the devices are LC resonating circuits made from High-Temperature Co-fired Ceramic (HTCC)aluminium oxide green tapes. For the fabrication, the tapes were screen-printed with platinum paste,micromachined, stacked, laminated and fired. The additional sensor element was made from the samematerial and with the same processes, and contains a cavity sealed with a capacitive membrane.Thermomechanical characterization was made by investigating the bimorphic behaviour due to CTEmismatch as well as the resonance frequency of the devices as a function of mechanical displacement.Also, the resonance frequency as a function of pressure was demonstrated for the device with anintegrated pressure sensor node. The wireless readings were performed with a tuneable resonating loopantenna. The devices showed a relatively low quality factor value. The bimorphic behaviour is lowwith only small variations for temperatures up to 400°C. As for the mechanical displacement, theresonance frequency was only affected for thin devices at forced deformations that were larger thanthose observed as a function of temperature. For the device with an integrated pressure sensor, a clearpressure-induced frequency shift of 6785 ppm was observed at 1.5 bar. This indicates that the devicesare robust for high temperatures and also applicable for pressure readings. Future work will furtherexpand on high-temperature characterization of the devices.

  • 45.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    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.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thermomechanical properties and performance of ceramic resonators for wireless pressure reading in high temperatures2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 9, article id 095016Article in journal (Refereed)
    Abstract [en]

    This paper reports on the design, fabrication and thermomechanical study of ceramic LC resonators for wireless pressure reading, verified at room temperature, at 500 °C and at 1000 °C for pressures up to 2.5 bar. Five different devices were fabricated of high-temperature co-fired ceramics (HTCC) and characterized. Alumina green tape sheets were screen printed with platinum paste, micromachined, laminated and fired. The resulting samples were 21 x 19 mm2 with different thicknesses. An embedded communicator part was integrated with either a passive backing part or with a pressure-sensing element, including an 80 μm thick and 6 mm diameter diaphragm. The study includes measuring thermally and mechanically induced resonance frequency shifts, and thermally induced deformations. For the pressure sensor device, contributions from changes in the relative permittivity and from expanding air, trapped in the cavity, were extracted. The devices exhibited thermomechanical robustness during heating, regardless of the thickness of the backing. The pressure sensitivity decreased with increasing temperature from 15 050 ppm/bar at room temperature to 2400 ppm/bar at 1000°C, due to the decreasing pressure difference between the external pressure and the air pressure inside the cavity. 

  • 46.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish Def Univ, Dept Mil Sci, Stockholm, Sweden.
    Klintberg, Lena
    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, Ångström Space Technology Centre (ÅSTC).
    Pirani Microgauge Fabricated of High-Temperature Co-fired Ceramics with Integrated Platinum Wires2019In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 8-16Article in journal (Refereed)
    Abstract [en]

    This paper presents the integration and pressure sensor operation of platinum bond wires in High-Temperature Co-fired alumina (HTCC). Devices were fabricated with a 50 μm diameter wire suspended across a 500 μm wide cavity in green-body state HTCC, electrically connected to screen printed alumina conductors. The substrate shrinkage during sintering to a cavity width of 400 μm causes the wire element to elevate from the cavity´s bottom surface. Resulting devices were compared with reference devices, containing screen-printed sensor elements, as Pirani gauges operated at 100 °C in constant-resistance mode, and in dynamic mode with a feeding current of 1 A in a pressure range from 10−4 Torr to atmospheric pressure. Also, devices with wire lengths between 500 and 3500 μm were operated and studied in constant-resistance and dynamic mode. Lastly, a device is demonstrated in operation at a mean temperature of 830 °C. The results include wire elements with a consistent elevation from their substrate surfaces, with irregularities along the wires. The wire devices exhibit a faster pressure response in dynamic mode than the reference devices do but operate similarly in constant-resistance mode. Increasing the wire element length shows an increasing dynamic pressure range but a decreasing maximum sensitivity. The sensitivity is retained in high temperature mode, but the dynamic range is extended from about 10 Torr to about 700 Torr.

  • 47.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Försvarshögskolan/Swedish National Defence College.
    Seton, Ragnar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Klintberg, Lena
    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, Ångström Space Technology Centre (ÅSTC).
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster2019In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 28, no 2, p. 235-244Article in journal (Refereed)
    Abstract [en]

    The research and development of small satellites has continued to expand over the last decades. However, the propulsion systems with adequate performance have persisted to be a great challenge. In this paper, the effects of three different heaters on the specific impulse and overall thrust efficiency of a cold gas microthruster are presented. They consisted of a conventional, printed resistive thick-film element, a freely suspended wire, and a stripline split-ring resonator microplasma source, and were integrated in a single device made from the high-temperature co-fired ceramics. The devices were evaluated in two setups, where the first measured thrust and the other measured shock cell geometry. In addition, the resistive elements were evaluated as gas temperature sensors. The microplasma source was found to provide the greatest improvement in both specific impulse and thrust efficiency, increasing the former from an un-heated level of 44–56 s when heating with a power of 1.1 W. This corresponded to a thrust efficiency of 55%, which could be compared with the results from the wire and printed heaters which were 51s and 18%, and 45s and 14%, respectively. The combined results also showed that imaging the shock cells of a plasma heated thruster was a simple and effective way to determine its performance, when compared to the traditional thrust balance method.

  • 48.
    Svensson, Karolina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Södergren, Simon
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-pressure microfluidic electrochemical and image analysis dual detection for HPLC2018Conference paper (Other academic)
    Abstract [en]

    High-performance liquid chromatography (HPLC) is often set as the lab-based golden standard. For point-of-care and point-of-site applications, making HPLC portable, easy to use and low cost, is very desirable. To reach lower costs, one important task is the development of suitable detectors. Because of the potential for low cost and high performance, a dual-detection microfluidic chip with an electrochemical detector (ECD) and optical access for image analysis was evaluated at high pressure, downstream an HPLC column. For the image analysis, a camera and near-UV-light was used to extract absorption data. To validate the response, a spectrometer was coupled downstream the chip. The results of the three different detectors were comparable, with the camera providing similar absorbance-time chromatograms as the spectrometer. However, the ECD registered only peaks from one of two analytes. To conclude, this experimental setup has potential to provide better understanding of the capability for microfluidic HPLC systems.

  • 49.
    Svensson, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ericson, Fredric
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    ESEM as a Tool for Studying High Temperature Electronics2011In: IMAPS High Temperature Electronics Network (HiTEN 2011), July 18-20, 2011 ,Oxford, UK, 2011Conference paper (Refereed)
    Abstract [en]

    Researchers studying materials and processes at high temperatures are often restricted to do evaluation afterwards and at room temperature using e.g. scanning electron microscopy (SEM). Limited by high vacuum, outgassing and non-conducting samples are difficult to study with SEM. For such samples, environmental scanning electron microscope (ESEM) is an alternative that is particularly suited also for high temperature in-situ studies. The electron detector in the ESEM make use of otherwise unwanted scattering of electrons as an amplifier of the signal, and by using differential pumping, it is possible to introduce several mbar of either oxygen, water vapor, or a gas of choice into the sample chamber while still maintaining the high-vacuum in the electron column. The auxiliary gas neutralizes surface charges built up by the electron beam, which makes it possible to image non-conductive and outgassing samples, thus making it possible to study e.g. polymeric and high temperature materials. Our ESEM, FEI XL30, have a heating stage making it possible to reach temperatures up to 1500°C. Equipped with electrical feed- throughs, the instrument can be used to study high temperature phenomena on electrically activated components.

    ESEM is an instrument that has found its use for biological and organic samples. However, less work has been done using it for high temperature processes. Here, we show real-time imaging of the sintering of dielectric and Ag thick-film prints on AlN substrates. The use of the electrical feed-throughs to activate electrical components and study them at high temperatures is also demonstrated. ESEM is a versatile tool for high temperature studies and in-situ analysis of electrical components, solder processes and different die-attach materials. 

  • 50.
    Svensson, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sharma, Gunjana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ogden, Sam
    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.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-Pressure Peristaltic Membrane Micropump With Temperature Control2010In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 19, no 6, p. 1462-1469Article in journal (Refereed)
    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.

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