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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Jämställdhet i läromedel : En granskning av hur tre läroböcker i svenska lever upp till jämställdhetskraven i Gy11

Gunnars, Jenny January 2017 (has links)
Gender equality is a central topic in the curriculum of the upper secondary school and it should permeate all of the school’s activities. The purpose of this study is to determine whether three textbooks written for the course Swedish 1 in upper secondary school lives up to the requirements of gender equality as stipulated in the curriculum. The textbooks are analyzed both by means of comparing how often women and men are mentioned in the texts, as well as by evaluating the adjectives and participles by which women and men are described. Gender theory and sociolinguistics form the basis for this study. Gender theory addresses gender roles and gender identity in relation to the power of society and norms. Sociolinguistics describes the language from different perspectives, such as gender. The analysis shows that men are more frequently mentioned in the texts than women are. Moreover, positively charged adjectives and participles are more commonly associated with the male gender. The analysis also shows that men are usually linked to the public sector by association to their proffesional titles, while women are connected with the family. This study concludes that the reviewed textbooks cannot be said to meet the gender equality requirements in the curriculum for the upper secondary school. Men are in focus and the books confirm prejudice that exists in the society against women and men. However, these books do not need to be dismissed. Teachers can use these to show and discuss the realationship between women and men in today’s society with their students. This way norms can become more developed and contribute to a more permissive climate in the future.
22

Bond strength of concrete plugs embedded in tubular steel piles

Nezamian, Abolghasem, 1968- January 2003 (has links)
Abstract not available
23

High-Resolution Studies of Silicide-films for Nano IC-Components

Jarmar, Tobias January 2005 (has links)
<p>The function of titanium- and nickel-silicides is to lower the series resistance and contact resistivity in gate, source and drain contacts of an integrated circuit transistor. </p><p>With decreasing dimensions, the low resistivity C54 TiSi<sub>2</sub> is not formed and stays in its high resistivity phase C49. It was found that a layer of niobium interposed between titanium and silicon, which is supposed to promote the C54 phase, led to the formation of the high resistivity C40 (Ti,Nb)Si<sub>2</sub> in both small and large contacts. </p><p>Increased interest in Si<sub>1-x</sub>Ge<sub>x</sub> layers led to the inclusion of the Ni-Si-Ge system in this project. The interaction between nickel and poly-Si<sub>0.42</sub>Ge<sub>0.58</sub> was found to be different from nickel and poly-silicon in the meaning of the phases formed during high temperature annealing. High-resistivity NiSi<sub>2</sub> was formed at 750°C, but nickel and Si<sub>0.42</sub>Ge<sub>0.58</sub> formed no disilicide. A massive out-diffusion of germanium from the NiSi<sub>1-u</sub>Ge<sub>u</sub> resulted in agglomeration at lower temperatures than for NiSi. This was ascribed to the larger enthalpy of formation for nickel reacting with silicon than with germanium. Ternary phase diagrams, with and without the disilicide phase, were calculated. According to the tie lines, NiSi<sub>1-u</sub>Ge<sub>u</sub> will be in thermodynamic equilibrium with Si<sub>1-x</sub>Ge<sub>x</sub> when u is smaller than x. This was confirmed experimentally, where a balanced germanium concentration in NiSi<sub>1-u</sub>Ge<sub>u</sub> and Si<sub>1-x</sub>Ge<sub>x</sub>, stabilized the germanosilicide. When nickel interacted with strained and relaxed silicon-germanium it was established that a strained substrate led to a morphologically unstable NiSi<sub>1-u</sub>Ge<sub>u</sub>. The germanosilicide was highly textured on both (001) and (111) substrates. The texturing was explained by the absence of Ni(SiGe)<sub>2</sub> which forced NiSiGe to reorient so as not to resemble a digermanosilicide at the film/substrate interface. NiSi<sub>0.82</sub>Ge<sub>0.18</sub> formed on p<sup>+</sup>-Si<sub>0.82</sub>Ge<sub>0.18</sub> in CBKs grew laterally under the SiO<sub>2</sub>, defining the contact hole. The contact resistivity extracted by 3D modelling was 5×10<sup>-8</sup> Ωcm<sup>2</sup>.</p>
24

High-Resolution Studies of Silicide-films for Nano IC-Components

Jarmar, Tobias January 2005 (has links)
The function of titanium- and nickel-silicides is to lower the series resistance and contact resistivity in gate, source and drain contacts of an integrated circuit transistor. With decreasing dimensions, the low resistivity C54 TiSi2 is not formed and stays in its high resistivity phase C49. It was found that a layer of niobium interposed between titanium and silicon, which is supposed to promote the C54 phase, led to the formation of the high resistivity C40 (Ti,Nb)Si2 in both small and large contacts. Increased interest in Si1-xGex layers led to the inclusion of the Ni-Si-Ge system in this project. The interaction between nickel and poly-Si0.42Ge0.58 was found to be different from nickel and poly-silicon in the meaning of the phases formed during high temperature annealing. High-resistivity NiSi2 was formed at 750°C, but nickel and Si0.42Ge0.58 formed no disilicide. A massive out-diffusion of germanium from the NiSi1-uGeu resulted in agglomeration at lower temperatures than for NiSi. This was ascribed to the larger enthalpy of formation for nickel reacting with silicon than with germanium. Ternary phase diagrams, with and without the disilicide phase, were calculated. According to the tie lines, NiSi1-uGeu will be in thermodynamic equilibrium with Si1-xGex when u is smaller than x. This was confirmed experimentally, where a balanced germanium concentration in NiSi1-uGeu and Si1-xGex, stabilized the germanosilicide. When nickel interacted with strained and relaxed silicon-germanium it was established that a strained substrate led to a morphologically unstable NiSi1-uGeu. The germanosilicide was highly textured on both (001) and (111) substrates. The texturing was explained by the absence of Ni(SiGe)2 which forced NiSiGe to reorient so as not to resemble a digermanosilicide at the film/substrate interface. NiSi0.82Ge0.18 formed on p+-Si0.82Ge0.18 in CBKs grew laterally under the SiO2, defining the contact hole. The contact resistivity extracted by 3D modelling was 5×10-8 Ωcm2.
25

Materials selection and evaluation of Cu-W particulate composites for extreme electrical contacts

Watkins, Bobby Gene, II 21 January 2011 (has links)
Materials for extreme electrical contacts need to have high electrical conductivity coupled with good structural properties. Potential applications include motor contacts, high power switches, and the components of electromagnetic launch (EML) systems. In particular, the lack of durability of these materials in rail components limits practical EML implementation. These rails experience significant amounts of Joule heating, due to extreme current densities, and subsequent thermally-assisted wear. New more durable materials solutions are needed for these components. A systematic materials selection study was executed to identify and compare candidate materials solutions. Several possible candidate non-dominated materials as well as hybrid materials that could potential fill the "white spaces" on the Ashby charts were identified. A couple potential candidate materials were obtained and evaluated. These included copper-tungsten W-Cu, "self-lubricating" graphite-impregnated Cu, and Gr-W-Cu composites with different volume fractions of the constituents. The structure-property relations were determined through mechanical and electrical resistivity testing. A unique test protocol for exposing mechanical test specimens to extreme current densities up to 1.2 GA/m2 was developed and used to evaluate these candidate materials. The systematic design of multi-functional materials for these extreme electrical contacts requires more than an empirical approach. Without a good understanding of both the tribological and structural performance, the optimization of the microstructure will not be quickly realized. By using micromechanics modeling and other materials design modeling tools coupled with systematic mechanical and tribological experiments, the design of materials for these applications can potentially be accelerated. In addition, using these tools, more complex functionally-graded materials tailored to the application can be systematically designed. In this study, physics- and micromechanics-based models were used to correlate properties to the volume fraction of the constituents of the evaluated candidate materials. Properties correlated included density, elastic modulus, hardness, strength, and electrical resistivity of the W-Cu materials.
26

Geometric and material nonlinear analysis of laminated composite plates and shells

Chandrashekhara, K. January 1985 (has links)
An inelastic material model for laminated composite plates and shells is formulated and incorporated into a finite element model that accounts for both geometric nonlinearity and transverse shear stresses. The elasto-plastic material behavior is incorporated using the flow theory of plasticity. In particular, the modified version of Hill's initial yield criterion is used in which anisotropic parameters of plasticity are introduced with isotropic strain hardening. The shear deformation is accounted for using an extension of the Sanders shell theory and the geometric nonlinearity is considered in the sense of the von Karman strains. A doubly curved isoparametric rectangular element is used to model the shell equations. The layered element approach is adopted for the treatment of plastic behavior through the thickness. A wide range of numerical examples is presented for both static and dynamic analysis to demonstrate the validity and efficiency of the present approach. The results for combined nonlinearity are also presented. The results for isotropic results are in good agreement with those available in the literature. The variety of results presented here based on realistic material properties of more commonly used advanced laminated composite plates and shells should serve as references for future investigations. / Ph. D.
27

Läroböckers och lärarhandledningars kopplingar till Lgr22 : Analys av läroböcker och tillhörande lärarhandledningar i de naturorienterande ämnena för årskurserna 1 – 3 / Textbooks and teacher guides’ connections to Lgr22 : Analysis of textbooks and associated teacher guides in science for grades 1 – 3

Eriksson, Alexandra, Spångedal, Anne-Sofie January 2024 (has links)
The purpose of the study is to add more knowledge about how two textbooks and teacher guides for science teaching in grade 1-3 relate to the central content of Lgr 22 and how they support teaching. The selected textbooks and accompanying teacher's guides are PULS NO-boken and Boken om NO 1-3. We have conducted a quantitative analysis of the textbooks and a qualitative analysis of the teacher guides. In the quantitative analysis, we have examined the extent to which the textbooks cover the central content. In the qualitative analysis, we used an existing framework for teacher guides.  The results show that both textbooks cover all parts of the central content, but to varying degrees. Boken om NO 1-3 contains the most systematic investigations and the only field study in the textbooks is found in Boken om NO 1-3. PULS NO-boken has more information than Boken om NO 1 - 3. The result regarding the teacher guides is that PULS NO-boken in comparison to Boken om NO 1 - 3 has more subject didactic information and suggestions and supports the teacher's subject knowledge through factual explanations.  Both textbooks cover all the core content prescribed by the curriculum. Thus, the choice between the textbooks lies with the teacher depending on which approach they prefer to use. Our conclusion is that the teacher's guide to PULS NO-boken benefits both teachers and students the most, as it is richer in subject-specific tasks and explanations than Boken om NO 1-3. / Syftet med studien är att tillföra mer kunskap om hur två läroböcker och lärarhandledningar för NO-undervisning årskurs 1–3 relaterar till det centrala innehållet i Lgr 22 och hur de stödjer undervisningen. De utvalda läroböckerna med tillhörande lärarhandledningar är PULS NO-boken och Boken om NO 1–3. Vi har gjort en kvantitativ analys av läroböckerna och en kvalitativ analys av lärarhandledningarna. I den kvantitativa analysen har vi granskat omfattningen av läroböckernas behandling av det centrala innehållet. I den kvalitativa analysen har vi använt oss av ett befintligt ramverk för lärarhandledningar. Resultatet visar att båda läroböckerna behandlar alla delar i det centrala innehållet, dock i varierande omfattning. Boken om NO 1 – 3 innehåller flest systematiska undersökningar och den enda fältstudien i läroböckerna återfinns i Boken om NO 1 – 3. Vidare skiljer sig mängden faktatext mellan läroböckerna. PULS NO-boken har fler faktameningar än Boken om NO 1 – 3. Resultatet beträffande lärarhandledningarna är att PULS NO-boken i jämförelse med Boken om NO 1 – 3 har fler ämnesdidaktiska uppgifter och förslag samt stöttar lärarens ämneskunskap genom faktaförklaringar. Båda läroböckerna behandlar allt centralt innehåll som läroplanen föreskriver. Således ligger valet mellan läroböckerna hos läraren beroende på vilket arbetssätt hen föredrar att använda. Vår slutsats är att lärarhandledningen till PULS NO-boken gynnar såväl lärare som elever mest, då den är rikare på ämnesspecifika uppgifter samt förklaringar än Boken om NO 1–3.
28

Induced magnetoelectric coupling at a ferroelectric-ferromagnetic interface

Carvell, Jeffrey David 08 November 2013 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Preparation and characterization of multiferroic materials in which ferroelectricity and ferromagnetism coexist would be a milestone for functionalized materials and devices. First, electric properties of polyvinylidene (PVDF) films fabricated using the Langmuir-Schaefer method have been studied. Films of different thickness were deposited on silicon substrates and analyzed using several techniques. X-ray diffraction (XRD) data showed that PVDF films crystallize at an annealing temperature above 130 °C. Polarization versus electric field (PE) ferroelectric measurements were done for samples prepared with electrodes. PE measurements show that the coercivity of the films increases as the maximum applied electric field increases. The coercivity dependence on the frequency of the applied electric field can be fitted as . The results also show that the coercivity decreases with increasing the thickness of PVDF film due to the pinning effect. Next, we have demonstrated that those PVDF properties can be controlled by applying an external magnetic field. Samples were created in a layered heterostructure, starting with a Fe thin film, PVDF above that, and followed by another thin film of Fe. Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to study the interface between PVDF polymer films and ferromagnetic iron thin films. Conventional EXAFS was applied to identify the structure of a Fe film sandwiched between two PVDF layers. An electric signal was then applied to the polymer to study the effects polarizing the polymer has on the Fe atoms at the interface. This shows that the Fe atoms diffuse into the PVDF layer at the interface between the two layers. Polarizing the film causes further diffusion of Fe atoms into the polymer. We also found that as the applied magnetic field is changed, the switching of electric polarization for the PVDF displayed a dependence on the external magnetic field. We also noticed that both the coercivity and polarization for the PVDF polymer display hysteretic features as the applied magnetic field is changed. We also found that the thickness of both the iron layers and the PVDF layer has an effect on the magnetoelectric coupling in our samples. The same strain applied to a thicker PVDF layer becomes tougher to flip the polarization compared to a thinner PVDF layer. As the iron film thickness increases, the strain also increases, and the polarization of the PVDF polymer is more easily flipped. We also found that the magnetoelectric sensitivity increases as both the PVDF and iron layers increase in thickness. We have shown that it is possible to control the ferroelectric properties of a PVDF film by tuning the magnetic field in a heterostructure. Our experiments show a coupling between the electric polarization and applied magnetic field in multiferroic heterostructures much larger than any previously reported values. Previous reports have used inorganic materials for the ferroelectric layer. Organic polymers have an electric dipole originating at the molecular level due to atoms with different electronegativity that are free to rotate. To flip the polarization, the chains must rotate and the position of the atoms must change. This increases the force felt locally by those chains. Using this polymer, we are able to increase the magnetoelectric coupling.
29

Arbetsgång efter brand i en kulturhistorisk byggnad : Med fokus på återställandet av konstruktionen / Work process after fire in a cultural historic building : With focus on restoration of the construction

Lundgren Mårtensson, Linda, Björkman Ioannou, Stephanie January 2019 (has links)
I aktuellt läge [2019] brister Sverige på att tillhandahålla förberedande planer för eventuella brandolyckor i byggnader med kulturhistoriskt värde. Brandolyckor på kulturminnesmärkta byggnader är inte frekventa och det saknas en standardiserad metod på hur återställandet kan hanteras efter en brandolycka på ett produktivt och hållbart sätt. Syftet med rapporten är att komma fram till en förenklad och mätbar standardiserad arbetsprocess genom att förbättra arbetet kring en brandolycka på kulturminnesmärkta byggnader, där förebyggande åtgärder, förbättringar under brandförloppet och återställande av objekt ingår. Rapporten görs med målen att bevara en god social hållbarhet och bevara det svenska kulturarvet för framtida generationer. Målet vid återställandet av en kulturhistorisk byggnad är att utseendet ska förbli oförändrat och att bevara det traditionella och ursprungliga skicket. Huvudobjekt som undersöks är kulturminnesmärkta byggnaden Kasern II på Skeppsholmen tillsammans med de två referensobjekten Katarina kyrka och Vildmannen 7. Huvudobjektet där en brandolycka bryter ut i september år 2016 håller idag [2019] på att återställas efter omfattande fuktskador från släckningsarbetet och brandskador på material som blev utsatta för höga temperaturer. Del av den standardiserade processen är att redovisa hur val av släckmedel kan avgöra omfattningen av fuktskador på materialet i byggnaden och hur släckmedlet och brandrester påverkar närliggande miljö ur ett hållbarhetsperspektiv. Även förebyggande brandskydd och önskvärt brandskydd efter restaureringsarbetet tas med. Rapporten bearbetar materialmässigt främst tegel och trä som oftast utgör den bärande stommen respektive bjälklaget i en kulturhistorisk byggnad. Genom att observera hur trämaterial och murverk reagerar vid hög temperatur och fukt vill författarna bedöma om de kan saneras och återanvändas eller behöver kasseras. Dessutom undersöks med fokus på återställande av konstruktionen, saneringsmetoder för att ta bort brandlukt och mikrobiologisk påväxt på trämaterial. Då målet vid återställande av en kulturminnesmärkt byggnad är att behålla den traditionella utformningen saneras det massiva teglet och träbalkarna i den utsträckning som går för att bevara dem. Dimensionering av brandskydd varierar för olika kulturminnesmärkta byggnader beroende på objektets utformning och ändamål. Som exempel för installation av sprinkler görs en avvägning mellan risk för brand och risk för eventuella fuktskador vid brand. Compressed air foam system [CAFS] är den släckningsutrustning som används under släckningsarbetet på Kasern II, som jämfört med andra släckningssystem avger mindre vatten och på så sätt minimerar fuktskador. Under brandförloppet hjälper aktuella ritningar, dokumentation och insatsplaner räddningstjänsten att utföra ett funktionellt släckningsarbete. Tegel är beständigt mot brand då det bränns under tillverkningsprocessen. Vid en brandolycka kan tegel spricka om sintringstemperatur överstigs eller vid snabb avkylning under släckningsarbete. Sprickor kan åtgärdas med förstärkning av murverk. Sprickor i tegel som är synligt för blotta ögat återanvänds om det inte finns en synlig fysisk skada på materialet. Trämaterialets hållfasthet försämras inte vid exponering av hög temperatur förutom i den brännskadade delen som kallas förkolningsdel och ligger i ytskiktet på balken efter brand. Förkolningsdelen kan mekaniskt hyvlas bort vid sanering. Mekanisk hyvling anses som en relativt enkel saneringsmetod och kräver inga kemiska miljöpåverkande ämnen. / In current situation [2019], Sweden is failing to provide preparatory plans for possible fire accidents in buildings with cultural-historical value. Because fire accidents on monumental buildings do not occur frequently, there is no standardized method on how to manage the restoration after the accident in a productive and sustainable manner. Purpose of the report is to produce a simplified standardized and measurable work process on how to improve arrangements during a fire accident on monumental buildings, where preventive measures, improvements during fire process and restoration of the building are included. The report is written with the aim of preserving good social sustainability and for preserving the Swedish cultural heritage for the future. The goal when restoring a cultural-historical heritage building is to maintain the classical appearance and to preserve the traditional and original condition. The main object reviewed is the cultural heritage building Kasern II on Skeppsholmen together with two more reference objects. The main object, where the fire accident takes place in September 2016, is today [2019] being restored after extensive moisture damage from the extinguishing work and fire damage to the material which was exposed to high temperature. Part of the standardized process is to describe how the choice of extinguishing agent can determine the extent of moisture damage to the material of the building and how pollution from the extinguishing agent and fire residues affect the neighboring environment from a sustainable point of view. Preventive fire protection and desirable fire protection after restoration work are also included. The report materially presents bricks and wood, which most often constitute the supporting structure and the floor structure of a cultural-historical building. By observing how wood materials and masonry react at high temperature and humidity, an assessment is made whether these materials can be decontaminated and reused or need to be discarded. In addition, with focus on restauration of the construction, decontamination methods for removal of fire odor and microbiological growth on wood materials are studied. Goal when restoring a building with cultural heritage is to maintain the traditional construction, therefore the solid brick and wooden beams are to be remedied to the extent required to preserve them. The choice of fire protection installations varies depending on the building's design and purpose. An example is the installation of sprinklers, which is a tradeoff between the risk of fire and the risk of possible moisture damage in the event of fire. Compressed air foam system [CAFS] is the extinguishing equipment used during extinguishing work on Kasern II which, compared to other extinguishing systems, emits less water therefore minimizing moisture damage. During the fire accident, updated drawings, documentation and action plans help the rescue service perform a functional extinguishing work. Bricks are resistant to fire as bricks are burned during manufacturing process. During a fire accident, bricks may crack if the sintering temperature is exceeded or in case of a rapid cooling during extinguishing work. Cracks can be restored with reinforcement on masonry. As cracks in brick are usually visible to the naked eye, bricks are reused if there is no visible physically damage to the material. The strength of wood material does not deteriorate when exposed to high temperature except in the burned part called char, which lies on the surface layer of the beam after fire exposure. The charring part can be mechanically planed away during sanitation. Mechanical planning is regarded as a relatively simple sanitation method and does not require any chemical environmentally impacting substances.
30

Sexualitet, samtycke och relationer i den anpassade grundskolan : En läromedelsanalys av ett digitalt läromedel / Sexuality, consent and relationships in the adapted primary school : A learning tool analysis of a digital learning tool

Högbom, Kajsa, Omberg, Alexandra January 2024 (has links)
Syftet med studien var att undersöka om det digitala inlärningsprogrammet Privatliv kan vara ett adekvat stöd för speciallärare i undervisning inom ämnesområdet sexualitet, samtycke och relationer i den anpassade grundskolan. Valet grundar sig i en avsaknad av anpassade läromedel som vänder sig till elever i anpassad grundskola. Undersökningen syftade till att synliggöra vilka normer läromedlet förmedlar, om alla delar i läroplansmålen för år 7–9 finns med, om det förmedlar ett riskperspektiv eller ett friskperspektiv gällande ämnesområdet samt hur läromedlet är anpassat för att möta elevers olika behov och förutsättningar. För att undersöka detta användes en kvalitativ metod med en socialkonstruktivistisk ansats. Inspirerad av den kritiska diskursanalysen har vi genomfört en läromedelsanalys för att komma åt det mer implicita innehållet. Resultat som framkommit visar att Privatliv kan vara ett adekvat stöd i undervisning, men däremot behöver några delar tillföras för att kunna innehålla alla läroplansmål. Några delar från läroplansmålen saknas och vissa delar anser vi kräver lite mer fördjupad kunskap kring. Anpassningar finns men programmet skulle nå fler elever och vara ett fördelaktigare stöd för undervisande speciallärare om innehållet skulle anpassas ytterligare. Privatliv förmedlar i överlag ett friskperspektiv. Läromedlet avviker från heteronormen genom att belysa homosexualitet och bisexualitet och en HBTQ-norm är framträdande. En slutsats i studien visar hur viktigt det är att granska läromedel, men även betydelsen av kompetent personal som ska undervisa eleverna med hjälp av läromedlet.

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