Spelling suggestions: "subject:"kemiska""
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Protein-based hydrogel electrolytes for stretchable Zn-ion batteriesByström, Lovisa January 2023 (has links)
Stretchable aqueous-based Zn-ion batteries have shown promise as a sustainable and safe energy storage system for wearable electronics used in healthcare, sports, soft robotics, and prosthetics. A battery consists of the active electrode, electrolyte, current collector, and encapsulation. In this work, we focus on the development of the electrolyte component, which is a hydrogel based on polymers. Natural polymers (e.g proteins, polysaccharides) are chosen over synthetic ones because they are biodegradable, abundant in nature, and environmentally sustainable. Here, a hydrogel based on gelatin (G) and kappa-carrageenan (kC) were prepared and evaluated. We observed that the addition of kC into the hydrogel composite improved its mechanical properties. Optimum conditions at weight ratios of G:kC -99:1 wt%, the hydrogel showed good mechanical strength with an elongation at break of 370 ± 28%, elastic modulus of 0.119 ± 0.0256 MPa, and reversibility during 100 cyclic stretching at 50% strain. The hydrogel had a reasonable ionic conductivity of 14.80 mS/cm and was successfully integrated into a battery with a capacity of 0.24 mA/cm2. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>
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Polyamidåtervinning; Är det lönsamt för ett konfektionsföretag med implementering av återvunnen polyamid i sin produktion?Sandrén, Elin January 2013 (has links)
Textilåtervinning är mycket aktuellt, främst för syntetiska fibrer då dess framställning påverkar miljön i hög grad. Dessutom utvinns de ur petrokemisk källa som är en ändbar resurs. Återvinningsindustrin för textilier fungerar i dagsläget inte optimalt, vilket motiverar detta examensarbete. Återvunnen polyester, från PET-flaskor eller textilier har funnits i ca 10 år men nu börjar även återvunnen polyamid lanseras på marknaden. Denna rapport ger en överskådlig bild över textil- och polyamidåtervinning. En parallell har dragits till mattindustrin där den tekniska apparaturen för återvinning är mer utvecklad. För att bli framgångsrik måste ett företag visa att det eftersträvar hållbar utveckling och ansvarar för det ”ekologiska fotavtryck” som dess produkter efterlämnar.Examensarbetet har utförts i samarbete med Houdini Sportswear AB, ett företag som tillverkar konfektion för sport- och friluftsliv. Syftet med rapporten är att undersöka om det är lönsamt för företaget att implementera återvunnen polyamid med avseende på pris, prestanda och miljö. Kemiskt återvunnen fiber anses vara av samma kvalitet som jungfrulig, för att undersöka om detta påstående är korrekt samt påvisa den återvunna polyamidens prestanda har mekaniska dragprovningstester utförts. / Program: Textilingenjörsutbildningen
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Olika sätt att undervisa om kemisk bindning : Om att utgå från polaritet i stället för bindningsstyrkai grundskolans senare år / Different ways to teach chemical bondingHagström, Magnus January 2019 (has links)
Elever har ofta problem att förstå kemisk bindning. De kan felaktigt tro att elektronerna i sig utgör bindningen eller att jonbindning är begränsad till en enda positiv och en enda negativ jon. Oktettregeln överbetonas som förklaring till bindning och kan felaktigt uppfattas som drivande kraft bakom bindning. Forskning föreslår alternativa teoretiska ramverk med större fokus på elektrostatiska krafter, elektronegativitet och polaritet. Kunskapen finns alltså men har inte fullständigt nått ut, vilket yttrar sig som brister i ämnesdidaktisk kompetens hos lärare och läromedelsförfattare. Med utgångspunkt i variationsteorin genomfördes ett kontrollerat experiment i två randomiserade elevgrupper i årskurs 9, för att utröna om förståelsen påverkas av den ordningsföljd i vilken olika bindningstyper presenteras. Resultaten visar ingen signifikant skillnad mellan grupperna. Eleverna beskriver svårigheter att förstå polaritet och moln av elektroner. Metoden att pröva olika förklaringsmodeller kan utvecklas och göras i större skala, eventuellt som en learning study.
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Spectroscopic study of titanium monohydride and storage ring experimentsDanielsson, Mathias January 2008 (has links)
<p>This thesis describes two projects, spectroscopy of the astrophysically relevant molecule TiH and its isotopologue TiD, and the dissociative recombination (DR) reaction of astrophysically and atmospherically relevant molecules. Emphasis in the thesis is on the first project.</p><p>A series of laser aided spectroscopic studies of TiH/TiD has been carried out. A search for forbidden transitions in the (green) B-X band of TiH was performed. This was followed by a rather bitter fight for the analysis of the perturbed and congested B-X band of TiD, and this was finally rewarding. A substantial extension of a previously reported analysis of this band was performed. The new analysis includes transitions between higher vibrational levels never previously identified. This made it possible to report the first experimentally derived equilibrium constants for the TiH/TiD molecules. There is a need for such results for metal hydrides in the work of calculating the opacity of the atmospheres of cool M and L type stars.</p><p>The DR storage ring experiments have been carried out at the ion storage ring CRYRING in Stockholm. Measurements of the branching fractions and DR rate constants of molecular ions have been done. These results find use in the modeling of the chemistry in interstellar clouds as well as of atmospheres, like the one of Titan, one of the moons of Saturn, which was recently visited by the spacecraft Cassini.</p>
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cfd modelling and experimental study on the fluid flow and heat transfer in copper heat sink designKarimpourian, Bijan January 2007 (has links)
<p>Abstract</p><p>This thesis is studying the heatsinks new designs for copper heatsinks which utilizes modelling and simulation by CFD, construction of prototypes and experimental works. Challenges and complications in manufacturing of copper heatsinks are expressed and finding the solutions to these hindrances involve in this work. Numerical efforts supported by fluent are made to promote investigation and approaching the goal in which serves the new opportunities for wider application of copper material in heat sinks.</p><p>However the thermal conductivity of copper is about double as aluminium but still aluminium heatsinks are commonly used for heat dissipation in computers.</p><p>Comparing of heat performance of two analogous heatsink of different materials, aluminium and copper, is conducted by numerical analysis in the CFD environment.</p><p>In addition to larger surface area and airflow velocity another solution for enhancement of heat dissipation is suggested.</p><p>Manufacturing solutions of copper heatsinks are proposed which will facilitate fabrication of more high performance copper heatsinks than the current heavy and expensive models.</p><p>Our first copper heat sink model is designed exclusively based on the technical observations and analyses of numerical simulation of two identical copper and aluminium heatsinks by CFD and as well as manufacturability concerns.</p><p>This heat sink is fabricated mechanically and is tested by a number of heat sources and high sensitive devices such as adhesive K type thermocouple, data acquisition 34970A in associated with HP Bench Link program.</p><p>An extent experimental work on aluminium heatsinks, integrated with forced convection, is performed in order to measure their thermal capacities.</p><p>Comparison of the heat performance of a typical aluminium heatsink, which was the best among the all aluminium heat sinks and proposed copper heatsink under identical experimental conditions, is performed.</p><p>Also in some numerical efforts, optimizing and predicting of the thermal characterization of the proposed heatsink with inclined free fins is developed. The model is scaled up in the fluent environment to predict its application in the cooling of larger heat generated electronic devices.</p><p>Impingement air-cooling mode of force-convection is adopted for heat dissipation from high power electronic devices in associated with the proposed inclined fin model.</p><p>Components of airflow velocity in the hollow spaces of the heatsink are discussed. Pressure drop and other thermal variables are analyzed analytical and by CFD code.</p><p>Another mechanical manufactured copper heat sink is investigated. A new design of the base and fins is optimized.</p><p>A three-dimensional finite volume method is developed to determine the performance of the proposed heatsink.</p><p>Thermal and hydraulic characterization of the heat sink under air-forced convection cooling condition is studied. The flow behavior around the fins and some other parts of the heat sink is analyzed by utilizing CFD code.</p><p>The hydraulic parameters including velocity profiles, distribution of static pressure, dynamic pressure, boundary layer and fluid temperature between the fins and in the passageway at the middle of the heat sink are analyzed and presented schematically.</p><p>Furthermore the thermal characteristic of the proposed heatsink is studied by contouring the three dimensional temperature distributions through the fins and temperature of the heat source by CFD code.</p>
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Sexualbrottslingen - monster eller människa?Törning, Ulrica January 2006 (has links)
<p>Lås in pedofilerna och kasta bort nyckeln. Tvångskastrera våldtäktsmännen. Samhällets dom mot sexualbrottslingarna är hård och vägen tillbaka för många omöjlig.</p><p>Möt sexualbrottslingen och de som arbetar med män vars handlingar väcker avsky.</p>
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cfd modelling and experimental study on the fluid flow and heat transfer in copper heat sink designKarimpourian, Bijan January 2007 (has links)
Abstract This thesis is studying the heatsinks new designs for copper heatsinks which utilizes modelling and simulation by CFD, construction of prototypes and experimental works. Challenges and complications in manufacturing of copper heatsinks are expressed and finding the solutions to these hindrances involve in this work. Numerical efforts supported by fluent are made to promote investigation and approaching the goal in which serves the new opportunities for wider application of copper material in heat sinks. However the thermal conductivity of copper is about double as aluminium but still aluminium heatsinks are commonly used for heat dissipation in computers. Comparing of heat performance of two analogous heatsink of different materials, aluminium and copper, is conducted by numerical analysis in the CFD environment. In addition to larger surface area and airflow velocity another solution for enhancement of heat dissipation is suggested. Manufacturing solutions of copper heatsinks are proposed which will facilitate fabrication of more high performance copper heatsinks than the current heavy and expensive models. Our first copper heat sink model is designed exclusively based on the technical observations and analyses of numerical simulation of two identical copper and aluminium heatsinks by CFD and as well as manufacturability concerns. This heat sink is fabricated mechanically and is tested by a number of heat sources and high sensitive devices such as adhesive K type thermocouple, data acquisition 34970A in associated with HP Bench Link program. An extent experimental work on aluminium heatsinks, integrated with forced convection, is performed in order to measure their thermal capacities. Comparison of the heat performance of a typical aluminium heatsink, which was the best among the all aluminium heat sinks and proposed copper heatsink under identical experimental conditions, is performed. Also in some numerical efforts, optimizing and predicting of the thermal characterization of the proposed heatsink with inclined free fins is developed. The model is scaled up in the fluent environment to predict its application in the cooling of larger heat generated electronic devices. Impingement air-cooling mode of force-convection is adopted for heat dissipation from high power electronic devices in associated with the proposed inclined fin model. Components of airflow velocity in the hollow spaces of the heatsink are discussed. Pressure drop and other thermal variables are analyzed analytical and by CFD code. Another mechanical manufactured copper heat sink is investigated. A new design of the base and fins is optimized. A three-dimensional finite volume method is developed to determine the performance of the proposed heatsink. Thermal and hydraulic characterization of the heat sink under air-forced convection cooling condition is studied. The flow behavior around the fins and some other parts of the heat sink is analyzed by utilizing CFD code. The hydraulic parameters including velocity profiles, distribution of static pressure, dynamic pressure, boundary layer and fluid temperature between the fins and in the passageway at the middle of the heat sink are analyzed and presented schematically. Furthermore the thermal characteristic of the proposed heatsink is studied by contouring the three dimensional temperature distributions through the fins and temperature of the heat source by CFD code.
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Spectroscopic study of titanium monohydride and storage ring experimentsDanielsson, Mathias January 2008 (has links)
This thesis describes two projects, spectroscopy of the astrophysically relevant molecule TiH and its isotopologue TiD, and the dissociative recombination (DR) reaction of astrophysically and atmospherically relevant molecules. Emphasis in the thesis is on the first project. A series of laser aided spectroscopic studies of TiH/TiD has been carried out. A search for forbidden transitions in the (green) B-X band of TiH was performed. This was followed by a rather bitter fight for the analysis of the perturbed and congested B-X band of TiD, and this was finally rewarding. A substantial extension of a previously reported analysis of this band was performed. The new analysis includes transitions between higher vibrational levels never previously identified. This made it possible to report the first experimentally derived equilibrium constants for the TiH/TiD molecules. There is a need for such results for metal hydrides in the work of calculating the opacity of the atmospheres of cool M and L type stars. The DR storage ring experiments have been carried out at the ion storage ring CRYRING in Stockholm. Measurements of the branching fractions and DR rate constants of molecular ions have been done. These results find use in the modeling of the chemistry in interstellar clouds as well as of atmospheres, like the one of Titan, one of the moons of Saturn, which was recently visited by the spacecraft Cassini.
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Sexualbrottslingen - monster eller människa?Törning, Ulrica January 2006 (has links)
Lås in pedofilerna och kasta bort nyckeln. Tvångskastrera våldtäktsmännen. Samhällets dom mot sexualbrottslingarna är hård och vägen tillbaka för många omöjlig. Möt sexualbrottslingen och de som arbetar med män vars handlingar väcker avsky.
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Förbättrad vattenanvändning på Björnekulla Fruktindustrier AB : för ökad lönsamhet och bättre miljöOlsson, John January 2010 (has links)
Björnekulla Fruktindustrier AB i Åstorp vill minska kostnaderna för sin vattenförbrukning i fabriken. Det är endast en liten del av den totala vattenkonsumtionen som hamnar i slutprodukten. Majoriteten av vattnet går åt för tvättning av råvaror och maskinell utrustning. Anledningen till att kostnaderna är höga är den stora andel kommunalt vatten som fabriken köper in. För att minskaden andelen har jag undersökt två alternativ, ett eget reningsverk för återanvändning av vatten och en ny vattentäkt. För att undersöka möjligheten för ett reningsverk har jag analyserat det aktuella vattnet och sorterat ut de ämnen och parametrar som är utanför gränsvärden. Lämpliga reningssteg för att reducera och korrigera dessa parametrar har dimensionerats och sats ihop till ett komplett reningsverk. Att anlägga en ny vattentäkt och tillföra fabriken rent grundvatten är ett enkelt alternativ för att minska kostnaderna. Geologiskt ligger dock fabriken i ett svårt område och det kan vara svårt att hitta tillräcklig mängd vatten. Resultatet är ett förslag som kommer minska fabrikens kostnader avsevärt.
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