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  • 1.
    Agalo, Faith
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Synthesis of Insulin-Regulated Aminopeptidase (IRAP) inhibitors2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for alternative cognitive enhancers has risen due to the fact that clinical trial results of the drugs currently approved for treating these disorders have not been satisfactory.

    IRAP has become a possible drug target for treating cognitive impairment brought about by Alzheimer’s disease, head trauma or cerebral ischemia, among others. This came after the revelation that Angiotensin IV enhances memory and learning. Angiotensin IV, the endogenous ligand of IRAP has been structurally modified with the aim of producing potent IRAP inhibitors. However, the peptidic nature of these inhibitors restricts their use; they are not likely to cross the blood brain barrier.

    Other strategies for generating IRAP inhibitors have been through structure-based design and receptor based virtual screening. These drug-like molecules have exhibited positive results in animal studies.

    IRAP inhibitors have been identified via a HTS of 10500 low-molecular weight compounds to give the hit based on a spirooxindole dihydroquinazolinone scaffold, with an IC50 value of 1.5 µM. In this project, some analogues to this hit compound have successfully been synthesized using a known method, whereas others have been synthesized after additional method development.

    The application of the developed method was found to be limited, because poor yield was obtained when a compound with an electron withdrawing substituent on the aniline was synthesized. As a result of this, modification of this method may be required or new methods may have to be developed to synthesize these types of analogues.

    Inhibition capability of 5 new spirooxindole dihydroquinazolinones was tested through a biochemical assay. Compound 6e emerged as the most potent inhibitor in the series, with an IC50 value of 0.2 µM. This compound will now serve as a lead compound and should be used as a starting point for future optimization in order to generate more potent IRAP inhibitors.

     

  • 2.
    Aguirre Castillo, José
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Optimisation of the bottom stirring praxis in a LD-LBE converter: Investigations and tests on phosphorous removal, nitrogen as stirring gas, and slopping2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The LD-process, called after the cities Linz and Donawitz, is used to convert pig iron into crude steel by blowing oxygen on top of the pig iron. A LD-LBE converter, Lance Bubbling Equilibrium, also stirs the melt trough a bottom stirring system.

    The bottom stirring in a LD-LBE converter is believed to have a positive effect alone on the phosphorous removal. Previous studies have shown that the temperature and slag composition are the main factors affecting phosphorus removal. Phosphorus binds to the slag easier at low temperature and to slag with certain levels of dissolved calcium (a process additive). Different praxes were tested and a better dephosphorisation was reached. The bottom stirrings effect on the dissolution of calcium additives is a possible explanation to the results and mechanisms presented in this study.

    The study also aimed to investigate the use of nitrogen as stirring gas instead of argon. Nitrogen is removed from the steel during the formation of carbon oxide gases. Nitrogen was used in varying amounts as stirring gas during the first half of the oxygen blow. It proved to be safe to use as long as there was a high content of carbon in the melt. However using nitrogen beyond half of the blow showed to be risky for nitrogen sensible steels; even in small amounts since there is not enough carbon left to degas the steel from nitrogen.

    Slopping happens when formed gas from the LD-process is trapped in the slag. The slag level rises and sometimes it floods the converter resulting in yield losses. The influence of the bottom stirring on slopping was studied, which resulted in the conclusion that slopping cannot be avoided by simply improving the bottom stirring.

    Although some verification studies remains to be done, if the suggestions based on the results of this thesis were employed, savings in the oxygen and stirring gas economies could be made. Not least improvements on the iron yield.

  • 3.
    Ahlgren, Maria
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry.
    Remediation of diclofenac in a non-sterile bioreactor using the white rot fungus Trametes versicolor2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    From an environmental perspective, it is interesting to assess new methods for efficient removal of drugs from wastewater. The purpose of this project was to assess the possibility of using the white rot fungus Trametes versicolor  to degrade diclofenac in a lab scale bioreactor. Two methods for quantitative analysis of diclofenac were developed, using GC-MS and UHPLC-Q-TOF (C18-column). Both methods were partly validated, with regard to sensitivity, linearity, accuracy and precision, which highlighted the superiority of UHPLC-Q-TOF over GC-MS. Two HILIC columns were also assessed, but proved unsuitable for quantitative analysis of diclofenac under the used conditions. The fungal mycelia were immobilized on plastic carriers in a nutrient solution. In initial E-flask experiments, 10 mg/L diclofenac was added to an active culture and a heat-killed control of T. versicolor . Samples were analyzed, and the results from the active culture indicated a 98% removal of diclofenac after 48 hours. The lab scale bioreactor was used in a semi-continuous mode with the influent containing 10 mg/L diclofenac. Samples were collected from the effluent to monitor the concentration over 7 days. The results showed a decline in concentration to a stable level of approximately 2 mg/L. The initial experiments showed that most of the removal (85%) was due to sorption of diclofenac, but a clear difference was seen between the active and heat-killed culture. It was impossible to conclude from the bioreactor experiment if the observed removal was due to sorption or to a combination of sorption and enzymatic remediation.

  • 4.
    Alam, Parvez
    et al.
    Univ Edinburgh, Inst Mat & Proc, Sch Engn, Edinburgh, Midlothian, Scotland.
    Sanka, Immanuel
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre. Univ Gadjah Mada, Fac Biol, KSK Biogama Marine Biol Study Grp, Yogyakarta, Indonesia.
    Alam, Lilja Piuli
    Int Baccalaureate Sch, Turku, Finland.
    Wijaya, Saka
    Univ Gadjah Mada, Fac Biol, Dept Trop Biol, Yogyakarta, Indonesia.
    Sintya, Erly
    Univ Edinburgh, Inst Mat & Proc, Sch Engn, Edinburgh, Midlothian, Scotland; Univ Gadjah Mada, Fac Biol, KSK Biogama Marine Biol Study Grp, Yogyakarta, Indonesia; Kings Coll London, Dept Imaging Sci, London, England; Kings Coll London, Biomed Engn Res Div, London, England.
    Handayani, Niken Satuti Nur
    Univ Gadjah Mada, Fac Biol, Lab Genet & Breeding, Yogyakarta, Indonesia.
    Rivero-Mueller, Adolfo
    Univ Turku, Turku Ctr Biotechnol, Turku, Finland; Åbo Akad Univ, Turku, Finland; Med Univ Lublin, Dept Biochem & Mol Biol, Lublin, Poland.
    The snapping shrimp dactyl plunger: a thermomechanical damage-tolerant sandwich composite2018In: Zoology (Jena), ISSN 0944-2006, E-ISSN 1873-2720, Vol. 126, p. 1-10Article in journal (Refereed)
    Abstract [en]

    The dactyl plunger of Alpheus sp. was found to be a layered composite, with mineral-rich outer and inner layers and a chitin-rich middle layer of high porosity. The chitin-rich middle layer is itself composed of several porous chitin laminae. Modelling heat conduction through the plunger cross-section revealed that the chitin-rich layer is able to insulate heat and retard its progress through the material. Heat accumulates in the plunger after a series of successive snaps and as such, its thermally resistant design can be considered most useful under the conditions of successive snapping. The plunger has a concurrent mechanical damage-tolerant design with biogenic mineral layers, viscous (chitin–mineral) interfaces, energy-dissipating porous chitin, and sidewalls composed of ordered, layered aragonite. The snapping shrimp plunger has a design that may protect it and internal soft tissues from thermomechanical damage during plunger–socket compression prior to cavitation bubble release.

  • 5.
    Aldujaili, Aya
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Berndtson, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Hedström, Tom
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Piccolo, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Rahmani, Zakaria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Åhlén, Michelle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Hur partikelstorleksfördelning påverkar kritiska parametrar för medicinska enheter2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Projektet har inriktning på Galdermas produkter Deflux och Solesta, de ämnen som produkterna är uppbyggda av (dextran och hyaluronsyra) har studerats laborativt. Ändringar av parametrar såsom koncentration av dextran men även i siktningsmetod (dubbel- respektive enkelsiktningar samt olika filterstorlekar) har genomförts. Resultatet av dessa ändringar har erhållits med hjälp av mikroskop, laserdiffraktometer samt dragprovare. De slutsatser som har kunnat dras från resultaten är att med ökad partikeldiameter erhålls en lägre extruderingskraft, oavsett om använd siktningsmetod var enkel- eller dubbelsiktning. Vidare så erhålls en större extruderingskraft med ökad koncentration av dextran.

  • 6.
    Alzahrani, Faris
    et al.
    Univ Lancaster, Dept Engn, Lancaster LA1 4YW, England..
    Aldehani, Mohammed
    Univ Lancaster, Dept Engn, Lancaster LA1 4YW, England..
    Rusi, Hao
    Queens Univ Belfast, Sch Chem & Chem Engn, Belfast BT7 1NN, Antrim, North Ireland..
    McMaster, Michael
    Queens Univ Belfast, Sch Chem & Chem Engn, Belfast BT7 1NN, Antrim, North Ireland..
    Fernandes, Daniel Luis Abreu
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Assabumrungrat, Suttichai
    Chulalongkorn Univ, Ctr Excellence Catalysis & Catalyt React Engn, Dept Chem Engn, Bangkok 10330, Thailand..
    tSaoir, Meabh Nic An
    Queens Univ Belfast, Sch Chem & Chem Engn, Belfast BT7 1NN, Antrim, North Ireland..
    Aiouachet, Farid
    Univ Lancaster, Dept Engn, Lancaster LA1 4YW, England..
    Gas Flow Visualization in Low Aspect Ratio Packed Beds by Three-Dimensional Modeling and Near-Infrared Tomography2015In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 54, no 51, p. 12714-12729Article in journal (Refereed)
    Abstract [en]

    Nonuniform local flow inside randomly porous media of gas solid packed beds of low aspect ratios ranging from 1.5 to 5 was investigated by three-dimensional modeling and near-infrared tomography. These beds are known to demonstrate heterogeneous mixing and uneven distributions of mass and heat. The effects of the confining wall on flow dynamics were found nonlinear, particularly for aspect ratios lower than 3. High velocities were mainly observed in regions near the wall of aspect ratio value of 1.5 and those of values higher than 3, owing to high local porosities in these zones. Mass dispersion characterized both by experimental near-infrared imaging and by particle tracking showed discrepancies with literature models, particularly for aspect ratios lower than 3. Uncertainties were more significant with the radial dispersion due to bed size limits. Beyond this value, the wall affected more the axial dispersion, confirming the nonlinear impact of the wall on global hydrodynamics.

  • 7.
    Andersson, Emma
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Konkreta förbättringsförslag på farmaceutisk produktion för minimering av skadat innehåll av Salazopyrin EN-tabs 500mg2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 8.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidics at High Pressures: Understanding, Sensing, and Control2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis explores understanding, sensing, and control in high-pressure microfluidics. The high-pressure regime allows fluids to be forced through narrow channels at substantial speed and creates conditions for fluids of high density and low viscosity—features desired in flow-based chemical analyses. With changes to pressure and temperature, fluid properties vary, and for miniaturized flow systems, sensing and control are needed.

    For miniaturized chemical analytics to utilize high-pressure fluids, like supercritical CO2, sensors are required for flow characterization. In this thesis, high-pressure tolerant sensors in glass chips have been developed and investigated. By the use of chip-integrated temperature, flow, and relative permittivity sensors, the variable behavior of supercritical CO2 or binary component CO2-alcohol mixtures have been investigated. To be able to change flow rates, a heat-based actuator chip has been developed. By a flow control system, which combines a relative permittivity sensor and heat actuated flow regulators on a modular system, the composition of binary component CO2-alcohol mixtures can be tuned and controlled with feedback.

    Flows of multiphase CO2-H2O hold promise for miniaturized extraction systems. In this thesis, parallel multiphase CO2-H2O flow has been studied. To achieve control, methods have been investigated where channels have been modified by the introduction of a guiding ridge and altered by a chemical coating. Flow is a dynamic process, where pressure and temperature can vary with time and place. As the properties of fluids containing CO2 may change with pressure and temperature, properties will also change with time and place. Because of this, instruments with spatial and temporal resolution are needed to better understand dynamic chemical effects at flow. In this thesis, a tool is presented to study the dynamic acidification of aqueous solutions that come in contact with flowing CO2.

    By a study performed to understand the strength and pressure tolerance of glass chips, it has been found that the fracture is not only determined by the applied pressure, but also on time and environment.

    List of papers
    1. Fracture strength of glass chips for high-pressure microfluidics
    Open this publication in new window or tab >>Fracture strength of glass chips for high-pressure microfluidics
    2016 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, article id 095009Article in journal (Refereed) Published
    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.

    Keywords
    glass, fracture strength, high pressure microfluidics, crack growth, temperature dependence
    National Category
    Other Engineering and Technologies not elsewhere specified
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-309983 (URN)10.1088/0960-1317/26/9/095009 (DOI)000402408400009 ()
    Funder
    Swedish Research Council, 2011:5037Knut and Alice Wallenberg Foundation
    Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2018-06-19Bibliographically approved
    2. Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression
    Open this publication in new window or tab >>Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression
    Show others...
    2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105001Article in journal (Refereed) Published
    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. 

    Keywords
    Supercritical fluids, microfluidics, carbon dioxide, partial least square regression, principal component analysis, fluid dynamics, multiphase flow
    National Category
    Engineering and Technology Other Materials Engineering
    Identifiers
    urn:nbn:se:uu:diva-253552 (URN)10.1088/0960-1317/25/10/105001 (DOI)000366827400017 ()
    Funder
    Swedish Research Council, 2011-5037Knut and Alice Wallenberg Foundation
    Available from: 2015-05-29 Created: 2015-05-29 Last updated: 2018-06-19Bibliographically approved
    3. Influence of surface modifications and channel structure for microflows of supercritical carbon dioxide and water
    Open this publication in new window or tab >>Influence of surface modifications and channel structure for microflows of supercritical carbon dioxide and water
    2016 (English)In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 107, p. 649-656Article in journal (Refereed) Published
    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. 

    Keywords
    Microfluidics, Supercritical CO2, Silane coating, Parallel flow, Segmented flow, Surface modification
    National Category
    Engineering and Technology Chemical Engineering
    Identifiers
    urn:nbn:se:uu:diva-253554 (URN)10.1016/j.supflu.2015.07.027 (DOI)000366077100077 ()
    Funder
    Swedish Research Council, 2011-5037Knut and Alice Wallenberg Foundation
    Available from: 2015-05-29 Created: 2015-05-29 Last updated: 2018-06-19Bibliographically approved
    4. Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics
    Open this publication in new window or tab >>Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics
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    2017 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 1, article id 015018Article in journal (Refereed) Published
    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.

    Keywords
    supercritical carbon dioxide, high pressure microfluidics, integrated electrodes, temperature sensing, flow sensing, glass
    National Category
    Other Engineering and Technologies not elsewhere specified
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-310063 (URN)10.1088/0960-1317/27/1/015018 (DOI)000388703300003 ()
    Funder
    Swedish Research Council, 2011-5037VINNOVAKnut and Alice Wallenberg Foundation
    Note

    Part financed through Swedish Agency for the Innovation System, Vinnova, through the Centre for Natural Disaster Science (CNDS)

    Available from: 2016-12-09 Created: 2016-12-09 Last updated: 2018-06-19Bibliographically approved
    5. A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows
    Open this publication in new window or tab >>A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows
    2019 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 165-172Article in journal (Refereed) Published
    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.

    Keywords
    Relative permittivity, Process control, CO2-expanded liquids, Binary fluid mixtures, High-pressure microfluidics
    National Category
    Chemical Engineering Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:uu:diva-353945 (URN)10.1016/j.sna.2018.11.015 (DOI)000456902600021 ()
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2019-02-25Bibliographically approved
    6. A microfluidic control board for high-pressure flow, composition, and relative permittivity
    Open this publication in new window or tab >>A microfluidic control board for high-pressure flow, composition, and relative permittivity
    2018 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 21, p. 12601-12608Article in journal (Refereed) Published
    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%.

    National Category
    Chemical Engineering
    Identifiers
    urn:nbn:se:uu:diva-353953 (URN)10.1021/acs.analchem.8b02758 (DOI)000449722500039 ()30269500 (PubMedID)
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2018-12-21Bibliographically approved
    7. Dynamic pH determination at high pressure of aqueous additive mixtures in contact with dense CO2
    Open this publication in new window or tab >>Dynamic pH determination at high pressure of aqueous additive mixtures in contact with dense CO2
    Show others...
    2018 (English)In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 136, p. 95-101Article in journal (Refereed) Published
    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.

    Keywords
    Supercritical fluid chromatography, High-pressure microfluidics, Additive salts, Dense CO, Multiphase flow, Image analysis
    National Category
    Chemical Engineering Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-353940 (URN)10.1016/j.supflu.2018.02.012 (DOI)000430767400011 ()
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2018-06-18 Created: 2018-06-18 Last updated: 2018-08-02Bibliographically approved
  • 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.
    Andersson, Rassmus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Silicon-based graphite electrodes for Li-ion batteries2018Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The cycling performance of silicon containing graphite electrodes as the anode in lithium-ion batteries has been investigated. Different electrode compositions of silicon, graphite, carbon black, sodium carboxymethylcellulose (CMC-Na), styrene–butadiene rubber (SBR) and using water as the solvent have been prepared and evaluated electrochemically by constant-current-constant-voltage (CCCV) cycling. To understand the impact on the cycling performance of the electrodes, the process parameters in the coating process have been evaluated by rheological measurements of the electrode slurries.

    The highest and most stable capacity was found for the electrode containing 5 wt% silicon (vs. graphite), 3 wt% binder, equal amount of the binders CMC-Na and SBR and 70 wt% solvent in the initial electrode slurry. It showed a stable capacity retention of 360 mAh/g after 315 cycles, before it faded. It was found that the CMC-Na and the solvent have a strong impact on the properties of the electrode slurry and the processing parameters. CMC-Na, the solvent and SBR were also found to be important for the adhesion of the electrode coating on the current collector. The worst cycling performance was obtained for electrodes containing 15 wt% silicon, a solvent amount below 65 wt% and a binder ratio of CMC-Na:SBR below 1:1. Different rheological behaviour for different silicon particles was found to depend on the surface area of the particles.

    The full text will be freely available from 2020-06-01 08:00
  • 14.
    Asfaw, Habtom Desta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Multifunctional Carbon Foams by Emulsion Templating: Synthesis, Microstructure, and 3D Li-ion Microbatteries2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Carbon foams are among the existing electrode designs proposed for use in 3D Li-ion microbatteries. For such electrodes to find applications in practical microbatteries, however, their void sizes, specific surface areas and pore volumes need be optimized. This thesis concerns the synthesis of highly porous carbon foams and their multifunctional applications in 3D microbatteries. The carbon foams are derived from polymers that are obtained by polymerizing high internal phase water-in-oil emulsions (HIPEs).

    In general, the carbonization of the sulfonated polymers yielded hierarchically porous structures with void sizes ranging from 2 to 35 µm and a BET specific surface area as high as 630 m2 g-1. Thermogravimetric and spectroscopic evidence indicated that the sulfonic acid groups, introduced during sulfonation, transformed above 250 oC to thioether (-C-S-) crosslinks which were responsible for the thermal stability and charring tendency of the polymer precursors. Depending on the preparation of the HIPEs, the specific surface areas and void-size distributions were observed to vary considerably. In addition, the pyrolysis temperature could also affect the microstructures, the degree of graphitization, and the surface chemistry of the carbon foams.

    Various potential applications were explored for the bespoke carbon foams. First, their use as freestanding active materials in 3D microbatteries was studied. The carbon foams obtained at 700 to 1500 oC suffered from significant irreversible capacity loss during the initial discharge. In an effort to alleviate this drawback, the pyrolysis temperature was raised to 2200 oC. The resulting carbon foams were observed to deliver high, stable areal capacities over several cycles. Secondly, the possibility of using these structures as 3D current collectors for various active materials was investigated in-depth. As a proof-of-concept demonstration, positive active materials like polyaniline and LiFePO4 were deposited on the 3D architectures by means of electrodeposition and sol-gel approach, respectively. In both cases, the composite electrodes exhibited reasonably high cyclability and rate performance at different current densities. The syntheses of niobium and molybdenum oxides and their potential application as electrodes in microbatteries were also studied. In such applications, the carbon foams served dual purposes as 3D scaffolds and as reducing reactants in the carbothermal reduction process. Finally, a facile method of coating carbon substrates with oxide nanosheets was developed. The approach involved the exfoliation of crystalline VO2 to prepare dispersions of hydrated V2O5, which were subsequently cast onto CNT paper to form oxide films of different thicknesses.

    List of papers
    1. Boosting the thermal stability of emulsion–templated polymers via sulfonation: an efficient synthetic route to hierarchically porous carbon foams
    Open this publication in new window or tab >>Boosting the thermal stability of emulsion–templated polymers via sulfonation: an efficient synthetic route to hierarchically porous carbon foams
    Show others...
    2016 (English)In: ChemistrySelect, ISSN 2365-6549, Vol. 1, no 4, p. 784-792Article in journal (Refereed) Published
    Abstract [en]

    Hierarchically porous carbon foams with specific surface areas exceeding 600 m2 g−1 can be derived from polystyrene foams that are synthesized via water-in-oil emulsion templating. However, most styrene-based polymers lack strong crosslinks and are degraded to volatile products when heated above 400 oC. A common strategy employed to avert depolymerization is to introduce potential crosslinking sites such as sulfonic acids by sulfonating the polymers. This article unravels the thermal and chemical processes leading up to the conversion of sulfonated high internal phase emulsion polystyrenes (polyHIPEs) to sulfur containing carbon foams. During pyrolysis, the sulfonic acid groups (-SO3H) are transformed to sulfone (-C-SO2-C-) and then to thioether (-C−S-C-) crosslinks. These chemical transformations have been monitored using spectroscopic techniques: in situ IR, Raman, X-ray photoelectron and X-ray absorption near edge structure spectroscopy. Based on thermal analyses, the formation of thioether links is associated with increased thermal stability and thus a substantial decrease in volatilization of the polymers.

    Keywords
    Emulsion-templated polymer, sulfonation, pyrolysis, spectroscopy, carbon foam
    National Category
    Materials Chemistry
    Research subject
    Chemistry with specialization in Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-283174 (URN)10.1002/slct.201600139 (DOI)000395395900026 ()
    Projects
    3D microbatteries
    Available from: 2016-04-11 Created: 2016-04-11 Last updated: 2017-10-30Bibliographically approved
    2. Emulsion-templated bicontinuous carbon network electrodes for use in 3D microstructured batteries
    Open this publication in new window or tab >>Emulsion-templated bicontinuous carbon network electrodes for use in 3D microstructured batteries
    2013 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 1, no 44, p. 13750-13758Article in journal (Refereed) Published
    Abstract [en]

    High surface area carbon foams were prepared and characterized for use in 3D structured batteries. Twopotential applications exist for these foams: firstly as an anode and secondly as a current collector supportfor electrode materials. The preparation of the carbon foams by pyrolysis of a high internal phase emulsionpolymer (polyHIPE) resulted in structures with cage sizes of 25 mm and a surface area enhancement pergeometric area of approximately 90 times, close to the optimal configuration for a 3D microstructuredbattery support. The structure was probed using XPS, SEM, BET, XRD and Raman techniques; revealingthat the foams were composed of a disordered carbon with a pore size in the <100 nm range resultingin a BET measured surface area of 433 m2 g-1. A reversible capacity exceeding 3.5 mA h cm2 at acurrent density of 0.37 mA cm-2 was achieved. SEM images of the foams after 50 cycles showed thatthe structure suffered no degradation. Furthermore, the foams were tested as a current collector bydepositing a layer of polyaniline cathode over their surface. High footprint area capacities of500 mA h cm-2 were seen in the voltage range 3.8 to 2.5 V vs. Li and a reasonable rate performancewas observed.

    Place, publisher, year, edition, pages
    United Kingdom: , 2013
    Keywords
    Carbon foam, High internal phase emulsion polymer, microbattery, 3D microbattery, Lithium ion
    National Category
    Chemical Sciences Materials Chemistry
    Research subject
    Materials Science; Chemistry; Materials Science; Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-210659 (URN)10.1039/C3TA12680C (DOI)000326463400009 ()
    Projects
    STEM-VR-Microbattery
    Funder
    Swedish Energy AgencySwedish Research Council
    Available from: 2013-11-12 Created: 2013-11-12 Last updated: 2017-12-06Bibliographically approved
    3. Emulsion-templated graphitic carbon foams with optimum porosity for 3D Li-ion microbatteries
    Open this publication in new window or tab >>Emulsion-templated graphitic carbon foams with optimum porosity for 3D Li-ion microbatteries
    (English)Manuscript (preprint) (Other academic)
    Keywords
    carbon, foam, graphitic, anode, three-dimensional, microbattery, lithium
    National Category
    Polymer Technologies Chemical Process Engineering Materials Chemistry Polymer Chemistry Inorganic Chemistry Physical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-312893 (URN)
    Funder
    Swedish Research Council, 2012–4681StandUp
    Available from: 2017-01-14 Created: 2017-01-14 Last updated: 2017-12-30
    4. Nanosized LiFePO4-decorated emulsion-templated carbon foam for 3D micro batteries: a study of structure and electrochemical performance
    Open this publication in new window or tab >>Nanosized LiFePO4-decorated emulsion-templated carbon foam for 3D micro batteries: a study of structure and electrochemical performance
    Show others...
    2014 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 6, no 15, p. 8804-8813Article in journal (Refereed) Published
    Abstract [en]

    In this article, we report a novel 3D composite cathode fabricated from LiFePO4 nanoparticles deposited conformally on emulsion-templated carbon foam by a sol–gel method. The carbon foam is synthesized via a facile and scalable method which involves the carbonization of a high internal phase emulsion (polyHIPE) polymer template. Various techniques (XRD, SEM, TEM and electrochemical methods) are used to fully characterize the porous electrode and confirm the distribution and morphology of the cathode active material. The major benefits of the carbon foam used in our work are closely connected with its high surface area and the plenty of space suitable for sequential coating with battery components. After coating with a cathode material (LiFePO4nanoparticles), the 3D electrode presents a hierarchically structured electrode in which a porous layer of the cathode material is deposited on the rigid and bicontinuous carbon foam. The composite electrodes exhibit impressive cyclability and rate performance at different current densities affirming their importance as viable power sources in miniature devices. Footprint area capacities of 1.72 mA h cm−2 at 0.1 mA cm−2 (lowest rate) and 1.1 mA h cm−2 at 6 mA cm−2(highest rate) are obtained when the cells are cycled in the range 2.8 to 4.0 V vs. lithium.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry: , 2014
    National Category
    Physical Chemistry Polymer Chemistry Materials Chemistry Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-228630 (URN)10.1039/C4NR01682C (DOI)000339861500051 ()
    Projects
    STEM-VR-Microbattery
    Available from: 2014-07-18 Created: 2014-07-18 Last updated: 2017-12-05Bibliographically approved
    5. Surface-oxidized NbO2 nanoparticles for high performance lithium microbatteries
    Open this publication in new window or tab >>Surface-oxidized NbO2 nanoparticles for high performance lithium microbatteries
    (English)Manuscript (preprint) (Other academic)
    Keywords
    niobium, oxide, nanoparticle, power, energy, carbon, foam, lithium, microbattery
    National Category
    Natural Sciences Inorganic Chemistry Materials Chemistry Physical Chemistry Condensed Matter Physics Materials Engineering Chemical Engineering
    Research subject
    Chemistry with specialization in Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-312894 (URN)
    Projects
    3D Lithium-ion microbattery
    Funder
    Swedish Research Council, 2012–4681StandUp
    Available from: 2017-01-14 Created: 2017-01-14 Last updated: 2017-12-30
    6. A one-step water based strategy for synthesizing hydrated vanadium pentoxide nanosheets from VO2(B) as free-standing electrodes for lithium battery applications
    Open this publication in new window or tab >>A one-step water based strategy for synthesizing hydrated vanadium pentoxide nanosheets from VO2(B) as free-standing electrodes for lithium battery applications
    Show others...
    2016 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 46, p. 17988-18001Article in journal (Refereed) Published
    Abstract [en]

    The synthesis of two dimensional (2D) materials from transition metal oxides, chalcogenides, and carbides mostly involve multiple exfoliation steps in which hazardous solvents and reagents are used. In this study, hydrated vanadium pentoxide (V2O5[middle dot]nH2O) nanosheets with a thickness of a few nanometers were prepared via a facile environmentally friendly water based exfoliation technique. The exfoliation process involved refluxing the precursor, vanadium dioxide (VO2(B)), in water for a few days at 60 [degree]C. The proposed exfoliation mechanism is based on the intercalation/insertion of water molecules into the VO2(B) crystals and the subsequent cleavage of the covalent bonds holding the layers of VO2(B) together. The thermal and chemical analyses showed that the approximate chemical composition of the nanosheets is H0.4V2O5[middle dot]0.55H2O, and the percentage of VV content to that of VIV in the nanosheets is about 80(3)% to 20(3)%. The exfoliated aqueous suspension of the V2O5[middle dot]0.55H2O nanosheets was successfully deposited onto multi-walled carbon nanotube (MW-CNT) paper to form free-standing electrodes with a thickness of the V2O5[middle dot]0.55H2O layer ranging between 45 and 4 [small mu ]m. A series of electrochemical tests were conducted on the electrodes to determine the cyclability and rate capability of lithium insertion into V2O5[middle dot]0.55H2O nanosheets. The electrodes with the thinnest active material coating ([similar]4 [small mu ]m) delivered gravimetric capacities of up to 480 and 280 mA h g-1 when cycled at current densities of 10 and 200 mA g-1, respectively.

    Keywords
    2D materials, vanadium oxides, free-standing, battery, lithium
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-311357 (URN)10.1039/C6TA06571F (DOI)000388505400010 ()
    Funder
    Swedish Research Council, 2012-4681Swedish Energy AgencyBerzelii Centre EXSELENTStandUp
    Available from: 2016-12-24 Created: 2016-12-24 Last updated: 2017-12-30
  • 15.
    Asfaw, Habtom Desta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tai, Cheuk-Wai
    Stockholm University.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Emulsion-templated graphitic carbon foams with optimum porosity for 3D Li-ion microbatteriesManuscript (preprint) (Other academic)
  • 16.
    Asfaw, Habtom Desta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Tai, Cheuk-Wai
    Stockholm University.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Surface-oxidized NbO2 nanoparticles for high performance lithium microbatteriesManuscript (preprint) (Other academic)
  • 17.
    Asfaw, Habtom
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Tai, Cheuk-Wai
    Stockholm University.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Surface-oxidized NbO2 nanoparticles for high performance lithium microbatteriesManuscript (preprint) (Other academic)
  • 18. Avila, M.
    et al.
    Burks, T.
    Akhtar, F.
    Gothelid, M.
    Lansåker, Pia C
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Toprak, M. S.
    Muhammed, M.
    Uheida, A.
    Surface functionalized nanofibers for the removal of chromium(VI) from aqueous solutions2014In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 245, p. 201-209Article in journal (Refereed)
    Abstract [en]

    Polyacrylonitrile (PAN) nanofibers functionalized with amine groups (PAN-NH2) were prepared using a simple one-step reaction route. The PAN-NH2 nanofibers were investigated for the removal of chromium(VI) from aqueous solutions. The adsorption and the kinetic characteristics were evaluated in batch process. The adsorption process showed pH dependence and the maximum Cr(VI) adsorption occurred at pH = 2. The Langmuir adsorption model described well the experimental adsorption data and estimated a maximum loading capacity of 156 mg/g, which is a markedly high value compared to other adsorbents reported. The kinetics studies indicated that the equilibrium was attained after 90 min and the experimental data followed a pseudo-second order model suggesting a chemisorption process as the rate limiting step. X-ray Photoelectron Spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) revealed that the adsorption of Cr(VI) species on PAN-NH2 was facilitated through both electrostatic attraction and surface complexation. High desorption efficiency (> 90%) of Cr(VI) was achieved using diluted base solutions that may allow the reuse of PAN-NH2 nanofibers.

  • 19. Bakke, J.
    et al.
    Hägglund, Carl
    Stanford University, Stanford, California, USA.
    Jung, H. J.
    Sinclair, R.
    Bent, S.
    Atomic layer deposition of CdO and CdxZn1−xO films2013In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 140, no 2-3, p. 465-471Article in journal (Refereed)
  • 20. Bakke, J.
    et al.
    Tanskanen, J.
    Hägglund, Carl
    Stanford University, Stanford, California, USA.
    Pakkanen, T.
    Bent, S.
    Growth characteristics, material properties, and optical properties of zinc oxysulfide films deposited by atomic layer deposition2012In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, p. 01A135-Article in journal (Refereed)
  • 21.
    Bengtsson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Investigation of Galvanic Corrosion between Graphite Gaskets and Stainless Steel Flanges2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At Forsmark, several cases of suspected galvanic corrosion have been detected and

    believed to be caused by an inappropriate use of graphite gaskets in brackish water.

    This report studies the likelihood of galvanic corrosion between the graphite gasket

    and stainless steels and aims to be a reference when investigating galvanic corrosion in

    the future. To evaluate galvanic corrosion, several electrochemical experiments were

    studied, such as galvanic series, polarization curves, and galvanic current

    measurements with a ZRA.

    The electrochemical results showed that when immersing the stainless steel (254

    SMO) and the graphite gasket (Novatec) into brackish water, there was a current

    flowing between the electrodes. However, the current was very small, which could be

    explained by the protection from a passive film on the stainless steel. The difference

    in corrosion potential between the two materials was measured and compared to

    results from polarization curves. It appeared that 254 SMO would be protected by a

    passive film at the measured potential. Galvanic current measurements also indicated

    the presence of a passive film under the investigated conditions.

    The results indicate that galvanic corrosion itself should not have caused the

    corrosion attacks at Forsmark. The found corrosion is more likely due to crevice

    corrosion that was accelerated by the combination of a crevice, a welded flange

    surface, chlorides in water and possibly a graphite gasket.

  • 22.
    Berts, Ida
    et al.
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Fragneto, Giovanna
    Institut Laue-Langevin.
    Hilborn, Jöns
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Rennie, Adrian R.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Tuning the density profile of surface-grafted hyaluronan and the effect of counter-ions2013In: European Physical Journal E, ISSN 1292-8941, Vol. 36, no 7, p. 70-Article in journal (Refereed)
    Abstract [en]

    The present paper investigates the structure and composition of grafted sodium hyaluronanat a solid-liquid interface using neutron reflection. The solvated polymer at the surface could be described with a density profile that decays exponentially towards the bulk solution. The density profileof the polymer varied depending on the deposition protocol. A single-stage deposition resulted in denser polymer layers, while layers created with a two-stage deposition process were more diffuse and had an overall lower density. Despite the diffuse density profile, two-stage deposition leads to a highersurface excess. Addition of calcium ions causes a strong collapse of the sodium hyaluronan chains, increasing the polymer density near the surface. This effect is more pronounced on the sample prepared by two-stage deposition due to the initial less dense profile. This study provides an understanding at a molecular level of how surface functionalization alters the structure and howsurface layers respond to changes in calcium ions in the solvent.

  • 23.
    Berts, Ida
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Ossipov, Dmitri
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Fragneto, Giovanna
    Institut Laue-Langevin.
    Frisk, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Rennie, Adrian. R
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Polymeric Smart Coating Strategy for Titanium Implants2014In: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. 16, no 11, p. 1340-1350Article in journal (Refereed)
    Abstract [en]

    Hyaluronan based hydrogel coatings can mimic extracellular matrix components and incorporate growth factors that can be released during a progressive degradation while new tissue regenerates. This paper describes a structural characterization of a hydrogel coating made of modified hyaluronan polymers and how these coatings interact with bone morphogenetic protein-2 (BMP-2). Quartz crystal microbalance and neutron reflectivity measurements were used for in-situ, real-time measurements of the adsorption properties of polymers and proteins on smooth titanium oxide surfaces that mimic implant products in orthopedics. The adsorption of BMP-2 on a bare titanium oxide surface is compared to that on titanium oxide coated with different chemically modified hyaluronan, the most important being hyaluronan with bisphosphonate groups (HA-BP). The subsequent release of the BMP-2 from these hydrogel coatings could be triggered by calcium ions. The amount of adsorbed protein on the surfaces as well as the amount of released protein both depend on the type of hyaluronan coating. We conclude that HA-BP coated titanium oxide surfaces provide an excellent material for growth factor delivery in-vivo.

  • 24.
    Björklund, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    The Influence of Hardness and Retained Austenite on the Fatigue Limit after Shot Peening2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was performed at Scania CV AB and aimed to optimize the effect of shot peening in order to increase the bending fatigue limit of planetary gears. In this project three parameters affecting the performance of the shot peening were examined in more detail, specifically the hardness of the shot peening media, the hardness of the material and the amount retained austenite.

    Shot peening and measurements were performed on carburized gears consisting of ss 92506 steel. In order to find out how the fatigue limit is affected by the material hardness, a number of gears were tempered whereas other remained untempered. Similarly the retained austenite content was altered in some of the gears with a cryotreatment. The shot peening of these gears was performed by dual shot peening using media of two different hardness. The fatigue limit was evaluated by a servo hydraulic material testing machine.

    The results show that the fatigue limit is enhanced when the shot peening was performed with hard media. This was expected since the harder media can cause larger plastic deformation in the material giving rise to larger compressive residual stresses which is known to increase the fatigue limit. The fatigue limit was also improved for samples with lower surface hardness. The amount of retained austenite does not seem to affect the fatigue limit for samples shot peened with media of sufficient hardness in order to cause adequate plastic deformation. The surface roughness remained unchanged for samples shot peened by different media, which indicates that this parameter should not hinder a change of media.

  • 25.
    Borg, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Synthetic bone grafts for treatment of femoral head necrosis2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Necrosis of the femoral head is a relatively common medical condition that radically

    decrease the quality of life for the patient. Left untreated it could lead to destruction

    of the hip joint. A common treatment is using bone autografts, also called bone chips.

    However, in the last decades synthetic bone grafts have become a very interesting

    alternative. This thesis had two aims; to evaulate how porous hydroxyapatite grafts

    with varied pore size could be produced by different size of the porogen and to

    create two-phase cements which would form pores in situ by using a dissolvable

    phase of calcium sulfate hemihydrate. The phase composition, morphology, porosity

    and pore size distribution were characterized with x-ray diffraction, scanning electron

    microscopy and micro-computed tomography. It was found that hydroxyapatite

    granules could be produced and it was possible to vary their pore size to some extent

    by changing the size of the porogen. At physiological temperature, pores were formed

    in the two-phase cements from one week and onwards.

  • 26.
    Bryngelsson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Relations between the performance of a coated cutting tool and the composition and properties of the wear resistant coating: A study including first principles modeling, mechanical properties and technological testing2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work was performed at AB Sandvik Coromant and aimed to enhance the knowledge about the relationships between the performance of TiN and TiAlN-coated cutting tools in metal turning and their mechanical and chemical properties.

    Measurements of coating material properties and turning wear tests in annealed tool steel Sverker 21, stainless steel 316L, grey cast iron V314 and nodular cast iron SS0727 were performed. The cutting temperatures were estimated from FEM-simulations. To find the dominant wear mechanism and identify the properties that are most important for the resistance against that particular wear, a correlation analysis was performed together with a wear study using LOM, SEM and EDS.

    The results show that relations between cutting performance and mechanical properties and/or composition of the coatings can be established. The FEM-simulations suggested that the peak tool temperature was highest, ~750°C, for turning in 316L and lowest for turning in Sverker 21, ~300°C. Turning in cast iron resulted in temperatures around 500-550°C.

    A mechanism for the growth of the crater on inserts tested in stainless steel 316L is proposed. Wear due to thermo-mechanical load and adhesion are believed to be the dominating wear mechanisms. The performance of the tool showed a high correlation to the composition of the coatings, with a decreased tool life for higher Al-contents. The reason for this might lie in an increased brittleness of these coatings, accelerating formation of lateral cracks above the crater. Calculated ratios of bulk and shear modulus suggests an increased brittleness for higher Al-contents. A higher tendency to stick to the work piece material might also contribute to a decrease in tool life. An Increased Al-content could also drive the formation of c-AlN to h-AlN, causing even higher wear rates. The coatings with higher substrate bias showed an enhanced performance, even though the crack pattern was worsened for these variants. The reason for the enhanced performance seen for these variants might instead originate in an enhanced adhesion to the substrate.

    In the flank wear resistance test in Sverker 21 the Al-content proved to be important, with an improved performance for higher Al-contents. In contrast to the test in 316L, a change in bias or hardness had no effect on the performance in this test. Scratch patterns on the flank supports that an abrasive wear mechanism is present, but no correlation between hardness and tool life could be obtained. Either some other material property than hardness is of importance for the abrasive resistance in this test, or another wear mechanism, occurring simultaneously with abrasion, is the wear rate deciding.

    The second part of this thesis work was to evaluate the ability of a quantum mechanical computational method, density functional theory, to predict material properties. The method predicts the lattice parameters and bulk moduli in excellent agreement with experimental values. The method also well predicts other elastic properties, with results consistent with reference values. There seems to be a constant shift of about 50-100 GPa between the calculated elastic modulus and the experimentally measured values, probably originating in contributions from grain boundaries, texture, stresses and defects present in the real coatings, and possibly also in errors in the experimental method due to an influence from the substrate. The calculated hardness values did not follow the trend of an increased hardness for TiAlN compared to TiN, which is seen in experiments.

  • 27.
    Buratovic, Emma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Cocalic, Dervis
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Eliasson, Kasper
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Danestig, Matilda
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Everlid, Linus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Controversial Materials: Ethical issues in the production of mineral based raw materials2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report has investigated the ethical issues associated with mining or processing of materials that make them considered as controversial. For each material, the main areas of use and the top producing countries are analysed, followed by social and/or environmental issues as well as potential problems in the future. In total, 13 materials are discussed, of which most are minerals. The overall issues, that are recurring throughout the report and are important to be aware of are: child labor, low safety standards, mining activity resulting in deforestation or harming biodiversity, mining processes that affect communities (e.g. because of large water consumption) and the risks associated with widespread illegal mining. The report also provides research about organisations and initiatives that aim to affect the problems, and gives a brief view over tools that can be used to increase awareness of these issues.

  • 28.
    Cai, Yixiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Chen, Song
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON, Canada..
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fabrication of translucent nanoceramics via a simple filtration method2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 121, p. 99848-99855Article in journal (Refereed)
    Abstract [en]

    Generally, particle packing density, grain size and morphology are the important factors that affect the transparency of ceramics. In order to achieve better transparency of ceramics, efforts should be developed to eliminate or minimize light scattering or absorption. Therefore the porosity and size of crystals in a ceramic body should be strictly controlled. Typical transparent ceramics are fabricated by pressure-assisted sintering techniques such as hot isostatic pressing (HIP), spark plasma sintering (SPS), and pressure-less sintering (PLS). However, a simple energy efficient production method remains a challenge. In this study, we describe a simple fabrication process via a facile filtration system that can fabricate translucent hydroxyapatite based ceramics. The translucent pieces yielded from filtration exhibit optical transmittance that was confirmed by UV spectroscopy. Briefly, the morphology and size of ceramic nanoparticles, filtration pressure and filtration time are important parameters to be discussed. Compared with different hydroxyapatite nanoparticles, spherical nanoparticles easily form a densely packed structure, followed by sintered ceramics. When the strontium content in HA increases, the morphology of HA changes from nano-spheres to nano-rods, following a decrease in transparency. A pressure filtration model combining Darcy's law and the Kozeny-Carman relation has been discussed to simulate and explain why the translucent ceramics can be fabricated via such a simple process. This method could be further applied to prepare other translucent functional ceramics by controlling the size and morphology of ceramic particles.

  • 29.
    Calmanovici Pacoste, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Boman, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Ardakani, Rebecka
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Degerman, Martina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Kammarbo, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Näslund, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Processdesign av emulsionsberedningssystem2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    At the request of Fresenius Kabi an emulsion preparation system was designed with a maximum production capacity of  15 L and minimum of 3 L emulsion. The system was required to consist of one oil-tank, one pre-emulsion tank, two storage tanks and one homogenizer. The storage tanks were positioned on a movable carriage on the left side of the homogenizer and the pre-emulsion tank and oil tank was placed on a separate frame on the right side of the homogenizer. All tanks were equipped with individual temperature control and a stand-alone parallel cleaning system was designed.

    The system also had to be optimized for the specific process and extensive calculations were done.  The emulsion system was designed using CAD-software and produced a detailed 3D-model. The tanks were designed from scratch and all other parts of the system consist of standardized components readily available. A list of the components in the system with manufacturer article number of all components was also produced. Actual drawings for the tanks were also made. The 3D-model and the list of components provide a good base for future construction of the system.

  • 30.
    Cedervall, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Synthesis and characterizationof rare earth free magnetic materialsfor permanent magnet applications2013Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis the compounds Fe5SiB2 and Fe5PB2 have beensynthesized via high temperature synthesis, including arc melting anddrop synthesis. The structure for both compounds are of Cr5B3 typewith the space group I4/mcm. The cell parameters were refined toa = 5.5533 Å and c = 10.3405 Å for Fe5SiB2 and a = 5.4903 Å andc = 10.3527 Å for Fe5PB2. The saturation magnetization at roomtemperature for Fe5SiB2 has been measured to 138.8 Am2/kg and theanisotropy constant has been estimated to 79 kJ/m3. Theferromagnetic properties and the high anisotropy constant makesthese materials promising as permanent magnet materials, but moreinvestigations are necessary.

  • 31.
    Chen, Wenju
    et al.
    Shanghai Univ, Sch Mat Sci & Engn, Shanghai 200444, Peoples R China.;Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Shi, Liyi
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Zhou, Hualan
    Univ Shanghai Sci & Technol, Sch Med Instrument & Food Engn, Shanghai 200093, Peoples R China..
    Zhu, Jiefang
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Wang, Zhuyi
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Mao, Xufeng
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Chi, Mingming
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Sun, Lining
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Yuan, Shuai
    Shanghai Univ, Res Ctr Nanosci & Nanotechnol, Shanghai 200444, Peoples R China..
    Water-Based Organic-Inorganic Hybrid Coating for a High-Performance Separator2016In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 4, no 7, p. 3794-3802Article in journal (Refereed)
    Abstract [en]

    With the development of electric vehicles, the traditional polyolefin separators can not meet the increasing requirements of lithium ion batteries with high power density, high energy density, and high safety performance. Herein, a novel water-based binder is synthesized by grafting carboxyl groups onto cellulose diacetate. When the polyethylene (PE) separator is coated by this binder and SiO2 nanoparticles, the thermal shrinkage of the modified separator is observed to be almost 0% after exposure at 200 degrees C for 30 min. The puncture strength significantly increase from 5.10 MPa (PE separator) to 7.64 MPa. More importantly, the capacity retention of the cells assembled with modified separators after 100 cycles at 0.5 C increase from 73.3% (cells assembled with PE separator) to 81.6%, owing to the excellent electrolyte uptake and the good compatibility with lithium electrode. Besides, the modified separator shows excellent surface stability after 100 cycles. Considering the above excellent properties, this composite separator shows high potential to be used in lithium ion batteries with high power density and safety.

  • 32. Cicek, Diana
    et al.
    Edin, Max
    Larsson, Alfred
    Petrovic, Alex
    Åberg, Anna
    An Investigation of Aspects Affecting Availability and Grading of High-risk Antibiotics in Sweden: Group 12019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis examined 39 antibiotics that, according to Folkhälsomyndigheten, were most likely to be affected by availability problems on the Swedish market. The aim was to investigate possible factors affecting the availability of the antibiotics, to grade the antibiotics based on these factors and, if possible, identify some pattern or general trend. A grading system for assessing the risk of availability problems for each antibiotic was created based on a number of factors, such as number of market authorization holders, number of active pharmaceuticalingredient manufacturers and risk of natural disasters in the countries where the antibiotic is produced. Each antibiotic got a final value based on all the factors, which was then compiled in a final table. The results were evaluated and discussed, both in general and for the specific antibiotics. In the discussion, relevant information that was not included in the grading system,such as isolated incidents at manufacturing sites, was taken into account. The information was successfully gathered and used to grade the antibiotics, but no pattern or general trends were identified.

  • 33.
    Cindemir, Umut
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Topalian, Zareh
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Porous Nickel Oxide Sensor for Formaldehyde Detection2014In: European Materials Society (E-MRS) Spring Meeting, Lille, France, May 26-30, 2014.: Symposium B: Advanced functional materials for environmental monitoring and applications., 2014Conference paper (Other academic)
    Abstract [en]

    Formaldehyde is a volatile organic compound, which is a harmful indoor pollutant, causing sick building syndrome (SBS) and is released from household and building materials. Since higher concentrations of formaldehyde are considered to be carcinogenic, monitoring them indoors is of great importance. Advanced gas deposition has here been used to fabricate highly porous nickel oxide (NiO) thin films for formaldehyde sensing. The films were deposited on Al2O3 substrates with prefabricated comb-structured electrodes, and a resistive heater at the opposite face. The morphology of the films was investigated with scanning electron microscopy, and the porosity was determined by nitrogen adsorption isotherms with the Brunauer-Emmett-Teller method. The particle size was found to be less than 10 nm, as determined by x-ray diffraction. X-ray photoelectron spectroscopy of the NiO films was also done. Gas sensing measurements were done using a total gas flow rate of 200 ml/min. Resistivity values of sensors were recorded with formaldehyde diluted in synthetic air. Sensor resistances were recorded at 50 ppm, 25ppm, 10ppm and 5 ppm formaldehyde concentration. NiO films showed promising formaldehyde gas sensing properties implying lower levels of detection limit.

  • 34.
    Congreve, Samantha
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Faris Elias, Reham
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Tidestav, Gabriel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Zafranian, Venus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Antibody drug conjugates (ADC): Current status and mapping of ADC:s in clinical programs2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A literature study was performed on a new type of cancer medicine: antibody drug conjugates, or ADCs. These consist of a monoclonal antibody, chemically linked to a cytotoxic agent. What makes them unique is their selective toxicity against cancer cells. The first approval of such a pharmaceutical was in the year 2000, with three or four available in different regions of the world today. In the range of 50 registered drugs in clinical development were found, by major and minor corporations. These have been presented in a table in the appendix according to their properties such as type of linker, cytotoxin, development status etc. Furthermore, a detailed study has been done of the chemistry of the linker conjugation as well as an attempt at studying the ADC market. Finally, the mentioned strengths of the drug were compared to its weaknesses, mainly instability and otherwise poor pharmacokinetics. The main conclusion is that these drugs are expected to play a major role in oncology in the future.

  • 35.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Lågdimensionella material för generering av solbränsle2017Conference paper (Other academic)
  • 36.
    Ekström, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Förutsättningar för ökad livslängd av sandlåsöverhettare2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Superheaters suffer large material loss during combustion of waste and biomass, causing a short life time for these expensive components. During combustion, corrosive ash particles are formed and erosion is caused by circulating bed material and sand particles, all contributing to the material loss. This study examines whether corrosion or erosion has the largest effect on this material loss by investigating two superheaters in loop seal during biomass and waste combustion of an 85 MW, Circulating Fluidized Bed (CFB) boiler in Händelö.

    The samples were investigated by SEM/EDX and XRD with regard to material loss and corrosion products. The superheaters have different thermal conditions since the material temperature in the first superheater that the steam passes is lower than in the one that comes after. In this report, a model to determine the tube temperature in steam boiler superheaters is also described due to the fact that the local tube temperature is of great importance of condensation of corrosive gases such as KCl and NaCl.

    Material loss was significantly greater on the cooler superheater compared with the warmer. The material temperatures on the outside of the tubes, were calculated to be about 574 °C for the cooler superheater and about 617°C for the warmer superheater. Overall, all analyzes showed low levels of corrosive substances, although there was a certain corrosion tendency, which indicates that material loss of the superheaters is caused by corrosion-assisted erosion. Lower material temperature of the superheater resulted in a higher degree of condensation of corrosive species such as alkali chlorides, which might have accelerated the erosion.

    The conclusion is that the dominant mechanism of material loss on the superheaters is erosion. 

  • 37. Ekvall, Kajsa
    Development of LC-QTOF method for analysis of extracts from urinary catheters2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Urinary catheters are made of polymers which in some cases contain a number of additives in order to get certain properties such as mechanical flexibility and prolonged shelf-life. To prove costumer safety, a manufacturer need to extract and analyse  these additives by a number of different methods. This master thesis presents the method development of a liquid chromatography-quadrupole time-of-flight instrument (LC-QTOF). The aim of the study was to produce a method that could separate and characterize five known additives in extracts from urinary catheters. The extraction of catheters was performed with 2-propanol according to International Organization of Standards, ISO 10993-12:2007. Starting with an already established liquid chromatography method with UV detection (LC-UV), known to separate the additives, two different columns were tested with a water-acetonitrile gradient. Early in the study, two different ion sources, the Electrospray (ESI) and Atmospheric pressure chemical ionization (APCI) were evaluated based on their ability to ionize the five additives. APCI turned out to be the superior ion source which also was supported by the literature. Therefore the method development was performed with APCI in positive mode. A study on how acid addition to the mobile phase affected the ionization was also conducted. The evaluation however indicated no improvement in ion signal for any of the additives. When evaluating the flow rate, it showed that the APCI ion source perform better at flow rates greater than or equal to 0.5 ml/min. To optimize the ion source six different parameters were varied in an experimental design using the software MODDE. The results showed that in order to increase the ionization of all five additives the method needed to be divided into two time segments with different parameter settings.

     

    The final method proved successful when analysing extracts from three different types of catheters. The aimed additives could be identified along with a number of unknown peaks. Some of the unknown peaks were later identified as Erucamide fragments by their masses and isotopic pattern.

  • 38.
    El Bari, Nezha el bari
    et al.
    Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    Diouf, Alassane
    Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    DIOUF, Alassane
    Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Bouchikhi, Benachir
    Moulay Ismaïl University, B.P. 11201, Zitoune, Meknes, Morocco.
    Development of an imprinted electrochemical sensor and its application for sensitive detection of malathion in olive fruits and oilsIn: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562XArticle in journal (Refereed)
    Abstract [en]

    Malathion (MAL) is an organophosphorus (OP) insecticide. It is a cholinesterase inhibitor, 15 which can pose serious health and environmental problems. In this study, a sensitive and 16 selective molecular imprinted polymer (MIP) based on screen-printed gold electrodes (Au-17 SPE) for MAL detection in olive oils and fruits, was devised. The MIP sensor was prepared 18 using acrylamide as the functional monomer and MAL as the template. Subsequently, the 19 morphology of the electrode surface was studied by scanning electron microscopy (SEM) and 20 atomic force microscopy (AFM). The electrochemical characterization of the developed MIP 21 sensor was performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), 22 and electrochemical impedance spectroscopy (EIS) techniques. The operational repeatability 23 and stability of the sensor were studied. It was found to have a dynamic concentration range 24 of (0.1 pg mL-1-1000 pg mL-1) and a low limit of detection (LOD) of 0.06 pg mL-1. 25 Furthermore, the sensor was employed to determine MAL content in olive oil with a recovery 26 rate of 87.9% and a relative standard deviation of 8%. It was successfully applied for MAL 27 determination in real samples and promise to open new opportunities for the detection of OP 28 pesticides residues in various food products, as well as in environmental applications.

  • 39.
    Emera, Flory
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Method development for copper dispersion evaluation and copper-based catalysts characterization2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    N2O chemisorption technique for copper dispersion determination was developed and optimized for accurate and reproducible results. With this technique, the bulk oxidation of pre-reduced catalyst can be prevented by N2O decomposition at low temperature (30oC). Only surface copper atoms are oxidized. The amount of freshly oxidized surface coppers is determined from H2-back-titration of fixed oxygen.The impact of temperature and time of exposure during oxidation was studied. Measurements made at higher temperature (60oC) resulted in overestimation of copper dispersion due to oxygen diffusion into the bulk and sub-layers. Much longer exposure time may also have an impact on copper dispersion estimation.For accurate results and good precision, it is recommended to work under mild conditions (isothermal oxidation at 30oC for 45 min.The developed method was successfully applied to fresh and spent catalyst. As expected, the copper dispersion for fresh catalyst was significantly higher than copper dispersion for spent catalyst.

  • 40.
    Englund, Sven
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Controlling Co-capping in sintering of cermets2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis includes a literature study and experimental work to understandthe conditions where a binder phase layer, Co-capping, could be produced orinhibited, for three different cermet grades in order to suggest changes in thesintering processes and two production units. The effect of C activity and sinteringatmosphere, e.g. flow rate, pressure were investigated. The results show that the Co-capping occurs on the cooling stage, when the binder phase, Co, solidifies. Co-capping could be inhibited by using a high C activity and high pressure (50 bar). Itwas further found that Co-capping could be evaporated using low pressure, i.e. vacuum, which has not been discussed in earlier studies on Co-capping. Evaporation was also found to have a relation with the solidification temperature of the grades,since grades with higher solidification temperature get Co-capping at a highertemperature, which consequently will be exposed to higher temperatures.

  • 41.
    Eriksson, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ti-Cu alloys for medical applications2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Bacterial infections caused by the formation of a biofilm on the implant aftersurgery is a severe problem affecting the implants long term function and often leading to implant failure. Copper is a natural trace element found in the human body, and has recently become a possible alloying element with strongantibacterial properties. In this master thesis, copper bearing titanium alloys with different concentrations of Cu (1, 3, 5 and 10 wt.% Cu) were prepared using two different heat treatments (T1 and T2) in order to kill the bacteria and prevent the formation of biofilms causing these infections. The antibacterial performance andCu ion release rate of the Ti-Cu alloys were investigated in order to determine their applicability as a biomaterial. The results from the experimental investigations showed that the addition of Cu provided the alloys with an antibacterial effect against Staphylococcus epidermidis. The alloys with 5 and 10 wt.% Cu had

    improved antibacterial properties, and the alloys with highest Cu content exhibited the strongest antibacterial ability with an antibacterial rate of 42% for the 10- Cu(T2) alloy and 48% for the 10-Cu(T1) alloy, after 6 hours. The Cu ion release rate of the Ti-Cu alloys with 1, 3 and 5 wt.% Cu were far below the daily recommended allowance according to WHO, while the alloys with 10 wt.% Cu showed Cu ion release rates substantially over the daily limit. For this reason, Ti- Cu alloys with less Cu content (>10 wt.%) are recommended. Nevertheless, Ti-Cu alloys have a promising future as a medical implant with antibacterial properties.

  • 42.
    Eriksson, Louise
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Method development and optimization for determination of lipid oxidation in emulsions2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Lipid emulsions in parenteral nutrition’s consist of two immiscible liquids described as oil in water phase. The oils in the emulsions can start to oxidize and make it become rancid. The oxidation can be measured for peroxide value, anisidine value and for free fatty acids (FFAs) as primary- and secondary oxidation products.

    This master thesis presents an analytical method used for analysis of oxidation products. The aim of this project was to come up with a method to separate the oil from the water-phase, to a sufficient yield and as pure as possible for analysis in a spectrophotometer called FoodLab fat. During the way experiments regarding stability of oils and finally a stability study on emulsions were done.

    Starting the separation experiments with ethanol to break the emulsion, this turned out to be the best way to go. Further investigation through extractions with 2- propanol/isooctane and ethanol/heptane were tested. The method needed to be simple, easy to use and not too time-consuming but still be repeatable and reliable.

    To optimize the separation, different centrifugation volumes, forces and times were tested. The results showed that in order to get the best separation the centrifugation volume and force cannot be too large or too small.

    The final method proved to be successful for the use as research method and to be able to see trends of oxidation for the products. Further research and validation of the instrument and the method needs to be done before it can be used as a quality control method. 

  • 43.
    Eriksson, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    The Establishment of a Small Challenger Company in a Segmented High-Technology Life Science Market: Challenges and Opportunities - a Model Case Study2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     This study aims to identify the challenges and opportunities of a small challenger

    company in a rigid and conservative high technology life science market. Strategies

    for finding a foothold, establish a position and creating a viable company is

    discussed. Qualitative and quantitative data was collected through interviews,

    online survey and conjoint analysis which were used as market research tools. For

    an entrepreneurial firm in the life science market it is important to tend to their most

    valuable resource, the employees, and it is vital that they have an extensive

    knowledge of the market that they are active in. Strategic planning tools and

    templates aid in executing and implementing the proposed business model.

    Recommendations for a model case entrepreneurial company regarding continued

    market research, increasing sales and strategies for marketing are made. Included

    in the thesis is also a discussion of wall effects in HPLC and ways to counteract

    them.

  • 44.
    Ersson, Nils Olov
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Förrådet av äldre instrument hos avdelningen för Oorganisk kemi, Uppsala Universitet: Beskrivning utgående från en dokumentation utförd 20082018Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Som del i masterexamen i museologi fick Hedda Gottberg och Rebecca Flodin 2008 i uppgift att dokumentera den samling av instrument som tillhörde avdelningen för Oorganisk kemi vid Uppsala Uni-versitet. Samlingen hade några år tidigare flyttats till en källarlokal i det nya Ångströmlaboratoriet i Uppsala. Denna dokumentation skedde under ledning av avdelningens prefekt Yvonne Brandt Anders-son och Nils Olov Ersson, pensionerad forskningsingenjör. Fotograferingen av alla föremålen, ofta från flera vinklar och alltid med angivande av föremålens angivna data, gav till resultat ett stort antal digitala filer. Ett urval av dessa fotografier med korta beskrivningar presenteras i denna skrift.

  • 45.
    Ferdowsi, Parnian
    et al.
    Univ Guilan, Fac Engn, Dept Text Engn, Rasht 416353756, Iran.;Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Saygili, Yasemin
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Zhang, Weiwei
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kavan, Ladislav
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland.;J Heyrovsky Inst Phys Chem, Prague 1823, Czech Republic..
    Mokhtari, Javad
    Univ Guilan, Fac Engn, Dept Text Engn, Rasht 416353756, Iran..
    Zakeeruddin, Shaik M.
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Grätzel, Michael
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Molecular Design of Efficient Organic D-A-pi-A Dye Featuring Triphenylamine as Donor Fragment for Application in Dye-Sensitized Solar Cells2018In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, no 2, p. 494-502Article in journal (Refereed)
    Abstract [en]

    A metal-free organic sensitizer, suitable for the application in dye-sensitized solar cells (DSSCs), has been designed, synthesized and characterized both experimentally and theoretically. The structure of the novel donor-acceptor--bridge-acceptor (D-A-pi-A) dye incorporates a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid (BTEBA). The triphenylamine unit is widely used as an electron donor for photosensitizers, owing to its nonplanar molecular configuration and excellent electron-donating capability, whereas 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid is used as an electron acceptor unit. The influences of I-3(-)/I-, [Co(bpy)(3)](3+/2+) and [Cu(tmby)(2)](2+/+) (tmby=4,4,6,6-tetramethyl-2,2-bipyridine) as redox electrolytes on the DSSC device performance were also investigated. The maximal monochromatic incident photon-to-current conversion efficiency (IPCE) reached 81% and the solar light to electrical energy conversion efficiency of devices with [Cu(tmby)(2)](2+/+) reached 7.15%. The devices with [Co(bpy)(3)](3+/2+) and I-3(-)/I- electrolytes gave efficiencies of 5.22% and 6.14%, respectively. The lowest device performance with a [Co(bpy)(3)](3+/2+)-based electrolyte is attributed to increased charge recombination.

  • 46.
    Fjällström, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Synthesis of CdZnS by Chemical Bath Deposition for Thin Film Solar Cells2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The buffer layer is a crucial component in thin film solar cells. Defects at the interface between absorber and buffer layer lead to high recombination rate and the band structure at the interface highly affects the performance of the solar cell. In this thesis a method to synthesize thin films containing cadmium, zinc and sulfur, CdZnS, by chemical bath deposition has been developed and evaluated. A higher current from the device is expected when replacing the common buffer layer cadmium sulfide, CdS, with the more transparent CdZnS. It is also possible that the alternative buffer provides a more favorable energy band alignment at the interface with the absorber Copper-Zinc-Tin-Sulfide (CZTS). The deposition process was developed by studying depositions on glass. Increasing [Zn2+]/[Cd2+] initially led to films with higher band gap (Eg). By varying deposition time the time before colloidal growth became dominant was observed. Addition of triethanolamine showed that triethanolamine binds stronger to zinc ions than to cadmium ions. Two recipes that led to Eg=2.63 eV were evaluated as buffer layer in Copper-Indium-Gallium-Selenide (CIGSe) and CZTS solar cells. The short circuit current of the devices increased in general with the CdZnS buffers compared to CdS. The best CZTS cell with a CdZnS buffer layer had 7.7 % efficiency compared to the 7.5 % reference. For future research it is recommended that the effect of thickness variation and deposition temperature is evaluated and that additional material characterization is performed in order to further understand and develop the deposition method.

  • 47.
    Fornell, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Johannesson, Carl
    Lund University.
    Searle, Sean S.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab. Natl Univ Singapore, Dept Biomed Engn, Fac Engn,.
    Happstadius, Axel
    Lund University.
    Nilsson, Johan
    Lund University.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    An acoustofluidic platform for non-contact trapping of cell-laden hydrogel droplets compatible with optical microscopy2019In: Biomicrofluidics, ISSN 1932-1058, E-ISSN 1932-1058, Vol. 13, article id 044101Article in journal (Refereed)
    Abstract [en]

    Production of cell-laden hydrogel droplets as miniaturized niches for 3D cell culture provides a new route for cell-based assays. Such production can be enabled by droplet microfluidics and here we present a droplet trapping system based on bulk acoustic waves for handling hydrogel droplets in a continuous flow format. The droplet trapping system consists of a glass capillary equipped with a small piezoelectric transducer. By applying ultrasound (4 MHz), a localized acoustic standing wave field is generated in the capillary, trapping the droplets in a well-defined cluster above the transducer area. The results show that the droplet cluster can be retained at flow rates of up to 76 mu l/min, corresponding to an average flow speed of 3.2 mm/s. The system allows for important operations such as continuous perfusion and/or addition of chemical reagents to the encapsulated cells with in situ optical access. This feature is demonstrated by performing on-chip staining of the cell nuclei. The key advantages of this trapping method are that it is label-free and gentle and thus well-suited for biological applications. Moreover, the droplets can easily be released on-demand, which facilitates downstream analysis. It is envisioned that the presented droplet trapping system will be a valuable tool for a wide range of multistep assays as well as long-term monitoring of cells encapsulated in gel-based droplets.

  • 48. Gemeiner, P.
    et al.
    Nahalka, J.
    Vikartovska, A.
    Nahalkova, J.
    Tomaska, M.
    Sturdik, E.
    Markovic, O.
    Malovikova, A.
    Zatkova, I.
    Ilavsky, M.
    Calcium pectate gel could be a better alternative to calcium alginate gel in multiple applications of immobilized cells1996In: Immobilized cells: basic and applications / [ed] Wijffels R.H., Buitelaar R.M., Bucke C., Tramper J., Netherlands: Elsevier, 1996, p. 76-83Chapter in book (Other academic)
  • 49.
    Ghaly, Montaser
    et al.
    National Research Centre (NRC), Chemical Engineering and Pilot Plant Department, Cairo, Egypt.
    Ali, Mohamed Eid
    National Research Centre (NRC), Water Pollution Research Department, P.O. 11312, Cairo, Egypt.
    Österlund, Lars
    FOI CBRN Defence and Security, Umeå.
    Khattab, Ibrahim
    National Research Centre (NRC), Chemical Engineering and Pilot Plant Department, Cairo, Egypt.
    Badawy, Mohamed
    National Research Centre (NRC), Water Pollution Research Department, P.O. 11312, Cairo, Egypt.
    Farah, Joseph
    National Research Centre (NRC), Chemical Engineering and Pilot Plant Department, Cairo, Egypt.
    Zaher, Fatama
    National Research Centre (NRC), Chemical Engineering and Pilot Plant Department, Cairo, Egypt.
    Al-Maghrabi, Mohammednoor
    Faculty of Engineering, King Abdul-Aziz University, Jedddah, Saudi Arabia.
    ZnO/spiral-shaped glass for solar photocatalytic oxidation of Reactive Red 1202014In: Arabian Journal of Chemistry, ISSN 1878-5352Article in journal (Refereed)
    Abstract [en]

    ZnO/glass spiral (GS) was prepared by immobilization of ZnO on GS with facilemethod, and was characterized by X-ray diffraction analysis (XRD), scanning electron microscope(SEM) and the crystallite size of ZnO on GS surface was calculated. SEM showed rod-like shape ofZnO particles on GS surface. Photocatalytic activity of prepared immobilized photocatalyst wasinvestigated for decolourization and degradation of C.I. Reactive Red 120 (RR-120) dye under sunlight.The kinetics of decolourization and degradation removal has been investigated. The effect ofpH on decolourization and degradation of dye was studied. The decolourization and degradation ofdye were followed by pseudo-first order reaction. The decolourization and degradation of RR-120dye were enhanced by H2O2 addition to definite dosage beyond that the effect is diminished. Also,the reusability of immobilized ZnO on GS was tested for photocatalytic degradation of dye and itwas worth noting that it has high efficiency with slight decrease (5%) after five successive runs.

  • 50.
    Ghanavi, Saman
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Organic-inorganic hybrid perovskites as light absorbing/hole conducting material in solar cells2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Solar cells involving two different perovskites were manufactured and analyzed. The

    perovskites were (CH3NH3)PbI3 and (CH3NH3)SnI3. Both perovskites have a

    shared methyl ammonium group (MA) and are used as both light absorbing material

    and hole conducting material (HTM) in this project. The preparation procedures for

    the complete device were according to previous attempts to make stable

    organic-inorganic hybrid perovskites and involved different layers and procedures.

    Both perovskites were manufactured by mixing methyl ammonium iodide with either

    lead iodide or tin iodide in different concentrations. This was then deposited on a

    600nm thick mesoporous TiO2 layer. Deposition of the hole-transporting material

    (HTM) was done by spin-coating 2,2´,7,7´-tetrakis-(N,N-dip-methoxyphenylamine)

    9,9´-spirobifluorene, also called spiro-OMeTAD. Lastly thermal evaporation was used

    to deposit a silver electrode.

    Different measurements were done on the light absorbing materials. The lead

    perovskite solar cell device was subjected to illumination with Air Mass 1.5 sunlight

    (100mW/cm2) which produced an open circuit voltage Voc of 0.645 V, a short circuit

    photocurrent Jsc of about 7 mA/cm2, and a fill factor FF of 0.445. This resulted in a

    power conversion efficiency (PCE) of about 2% and an incident photon to current

    efficiency (IPCE) of up to 60%.

    The tin perovskite has not been used in solar cells before and the initial results

    presented here shows low performance using the same device construction as for the

    lead perovskite. However, the incident photon to electron conversion affirms that

    there is a current in the visible region, and IPCE of 12.5 % was observed at 375nm.

    UV-visible NIR measurement was used to analyze the light absorption of the

    perovskite structures and a broader light absorption was observed for the lead

    perovskite compared to the tin perovskite.

    X-ray diffraction (XRD) analyzing was done on both perovskite materials using

    different concentrations and both with and without nanoporous TiO2 film. Both

    perovskites demonstrate very similar peaks with some exceptions.

    Photo-induced absorption (PIA) measurement was used for the purpose of showing

    the magnitude of charge separation or hole transfer in the light absorbing material,

    both when using the perovskites as a light absorber and a hole conductor. This is

    measured by analyzing the hole injection from the excited light absorber into the

    HTM. Hole transfer was observed for the lead perovskite (when used as light

    absorber) and tin perovskite (when used as hole conductor).

1234 1 - 50 of 169
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