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Arbetets bakgrund är en studie av hur produktutvecklings- och produktionsstegen ser ut i teorin för klädföretag som produktutvecklar genom ”snabbt marknadsbesvarande genom korta ledtider” och producerar genom det ”progressiva buntsystemet”. Jag presenterar de olika processerna och vilka svårigheter de bär med sig. I arbetets metoddel är samma processer studerade i praktiken hos intermediära företag och fabriker i Kina och tre nordiska ”fast-fashion”-företag. Detta görs genom intervjuer med respondenter från de olika aktörerna i värdekedjan. Vidare har jag även studerat dessa företags produktionsresultat. Detta för att se om det finns samband mellan modeföretagens praktiska arbetssätt för produktutveckling och kvalitén på deras produktionsresultat. I diskussionen ramas de mest effektiva metoderna för produktutveckling in och jämförs med modeföretagens förhållningssätt. Utifrån intervjuer och produktionsresultat drar jag slutsatsen att ju mer designers och personal med teknisk kunskap samarbetar internt i desto högre grad säkerställs bolagets produktionskvalité, samtidigt som korta ledtider bibehålls. Därtill är det till stor fördel för kvalitén om modeföretagen aktivt söker konsultation från deras sina leverantörer vid varje produktionstillfälle, angående exempelvis vilka materialval och lämpliga makningsdetaljer som passar bäst för den specifika leverantörens fabrik. Bolagen bör dessutom fokusera mer på att skapa individuellt anpassade kommunikationslösningar, utveckla långa leverantörsrelationer, använda utförligt beskrivna kvalitetsmanualer och arbeta med högre närvaro av kvalitetskontrollanter på fabrikerna än vad de gör idag. Utifrån fallstudierna ser jag ett tydligt samband: ju större ett bolag är och ju längre tid modebolaget det varit etablerat på den kinesiska marknaden desto mer har de utvecklat ovanstående parametrar, och uppnår därför högre kvalité och smidigare produktionslösningar än de bolag som inte varit etablerade lika lång tid. / Program: Textilingenjörsutbildningen

<p>Spin filtering properties of novel GaNAs alloys are reported in this thesis. Spin-dependent recombination (SDR) in GaNAs via a deep paramagnetic defect center is intensively studied.  By using the optical orientation photoluminescence (PL) technique, GaNAs is shown to be able to spin filter electrons injected from GaAs, which is a useful functional property for integratition with future electronic devices.  The spin filtering ability is found to degrade in narrow GaNAs quantum well (QW) structures which is attributed to (i) acceleration of band-to-band recombination competing with the SDR process and to (ii) faster electron spin relaxation in the narrow QWs.  Ga interstitial-related defect centers have been found to be responsible for the SDR process by using the optically detected magnetic resonance (ODMR) technique. The defects are found to be the dominant grown-in defects in GaNAs, commonly formed during both MBE and MOCVD growths.  Methods to control the concentration of the Ga interstitials by varying doping, growth parameters and post-growth treatments are also examined.</p>

Ett problem inom klädindustrin är att kläder kasseras på grund av att defekter uppstår. Defekter på kläder granskas oftast under produktionen men inte lika ofta efter användning. Denna studie fyller delvis detta gap då karaktär, placering och klassificering av defekter undersöks på kasserade arbetsbyxor. Studien har fokuserat på defekter som klassats som mycket allvarliga, vilket visat att defekterna främst uppstår i form av hål på tyg på framsidan och därefter som nötning vid grenen. Det utvecklades lösningar för de två vanligaste förekommande defekterna som klassificeras som mycket allvarliga. Gällande defekter med hål på framsidan utvecklades en åtgärd i form av ett informationsblad med skötselråd och förslag på ändring av material. För att minska uppkomsten av defekten nötning i grenen skapades olika konstruktionslösningar i form av två olika grenkilar och en justering av grensömmen. För att validera resultatet skapades en enkät som personer inom textilbranschen svarade på. Angående lösningarna för tyghål framkom det av enkätsvaren att endast materialbyte eller det i kombination med informationsblad om skötsel skulle kunna minska uppkomsten av defekten. Av enkäten framkom även att grenkilarna var den lösning som respondenterna ansåg var mest effektiv för att lösa problemet med nötning i grenen. / An existing problem in the clothing industry are garments discarded due to defects. These defects are usually examined in production and not as often after the garments have been worn. This study fills this gap partially by investigating the nature, placement and classification of defects on discarded working trousers. The compiled data showed that the most common critical defects were fabric holes at the front and abrasion at the crotch. After identifying the most common critical defects solutions were developed. Regarding the fabric holes two solutions were created, one was an information sheet on how to handle the garment and another one was a suggestion of change of fabric. Suggested solutions for critical abrasion at the crotch were two different gussets and adjustment of the back rise curve. A survey was conducted to validate and receive comments from the textile industry on the studies results. Regarding the fabric holes, the survey showed that change of fabric as a separate solution or in combination with information about the maintenance of the trousers were the most effective solutions. The survey also showed that gussets were the solutions that was considered the most effective in solving the problem of abrasion at the crotch.

This study characterizes production-line defects in lithium-ion batteries' anode, cathode, and separators. Lithium-ion batteries demand has increased tremendously in the last decades due to their use in various applications, including electric vehicles, portable electronics, and energy storage systems. Therefore, characterizing defects in these batteries is crucial to understand their performance and reliability. This study uses scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis to identify and analyze defects in the battery components. The major critical defects encountered in the study are impurities, contaminations, agglomerates, point defects, line defects, and more. This study helps improve the quality and reliability of lithium-ion batteries by providing guidelines to analyze and address essential deficiencies during the manufacturing process. / Denna studie karakteriserar produktionslinjedefekter i litiumjonbatteriers anod, katod och separatorer. Efterfrågan på litiumjonbatterier har ökat enormt under de senaste decennierna på grund av deras användning i olika applikationer, inklusive elfordon, bärbar elektronik och energilagringssystem. Därför är det avgörande att karakterisera defekter i dessa batterier för att förstå deras prestanda och tillförlitlighet. Denna studie använder svepelektronmikroskopi (SEM) och energidispersiv röntgenspektroskopi (EDS) analys för att identifiera och analysera defekter i batterikomponenterna. De största kritiska defekterna som påträffats i studien är föroreningar, föroreningar, agglomerat, punktdefekter, linjedefekter med mera. Denna studie hjälper till att förbättra kvaliteten och tillförlitligheten hos litiumjonbatterier genom att tillhandahålla riktlinjer för att analysera och åtgärda väsentliga brister under tillverkningsprocessen

Studien har klart och tydligt resulterat i att ett antalspecifika resultat rörande betydelsen av olika materialsammansättningars påverkan kornbildningen. Resultaten visar på vilka orsaker som finns för denna kornbildning samt hur färgsammansättningen kan varieras för att minska detta problem. / A study of grain formation in linseed oil-based paint have been conducted. The grains were formed in linseed oil paints with either Yellow1, Yellow 2, Black, or Red as the pigments. There are two types of grain formation which has been observed from the paint samples. (a) The grains which immediately appear in the newly made paint with Yellow 1, Yellow 2, and Red paints (b) while the other type is the grain that developed as the function of storage time in Black linseed oil paint. The results clearly show the cause of the defects.

In this Thesis a set of functional solid oxides for industrial applications have been addressed by first principles and thermodynamical modelling. More specificially, measurable quantities such as Gibbs free energy, geometry and electronic structure have been calculated and compared when possible with experimental data. These are crystalline and amorphous aluminum oxide (Al2O3), Zirconia (ZrO2), magnesium oxide (MgO), indiumoxide (In2O3) and Kaolinite clay (Al2Si2O5(OH)4). The reader is provided a computation tool box, which contains a set of methods to calculate properties of oxides that are measurable in an experiment. There are three goals which we would like to reach when trying to calculate experimental quantities. The first is verification. Without verification of the theory we are utilizing, we cannot reach the second goal -prediction. Ultimately, this may be (and to some extent already is) the future of first principles methods, since their basis lies within the fundamental quantum mechanics and since they require no experimental input apart from what is known from the periodic table. Examples of the techniques which may provide verification are X-Ray Diffraction (XRD), X-ray Absorption and Emission Spectroscopy (XAS and XES), Electron Energy Loss Spectroscopy and Photo-Emission Spectroscopy (PES). These techniques involve a number of complex phenomena which puts high demands on the chosen computational method/s. Together, theory and experiment may enhance the understanding of materials properties compared to the standalone methods. This is the final goal which we are trying to reach -understanding. When used correctly, first principles theory may play the role of a highly resolved analysis method, which provides details of structural and electronic properties on an atomiclevel. One example is the use of first principles to resolve spectra of multicomponentsamples. Another is the analysis of low concentrations of defects. Thorough analysis of the nanoscale properties of products might not be possible in industry due to time and cost limitations. This leads to limited control of for example low concentrations of defects, which may still impact the final performance of the product. On example within cutting tool industry is the impact of defect contents on the melting point and stability of protective coatings. Such defects could be hardening elements such as Si, Mn, S, Ca which diffuse from a steel workpiece into the protective coating during high temperature machining. Other problems are the solving of Fe from the workpiece into the coating and reactions between iron oxide, formed as the workpiece surface is oxidized, and the protective coating. The second part of the computational toolbox which is provided to the reader is the simulation of solid oxide synthesis. Here, a formation energy formalism, most often applied to materials intended in electronics devices is applied. The simulation of Chemical Vapour Deposition (CVD) and Physical Vapor Deposition (PVD) requires good knowledge of the experimental conditions, which can then be applied in the theoretical simulations. Effects of temperature, chemical and electron potential, modelled concentration and choice of theoretical method on the heat of formation of different solid oxides with and without dopants are addressed in this work. A considerable part of this Thesis is based upon first principles calculations, more specifically, Density Functional Theory (DFT) After Kohn and Pople received the Nobel Prize in chemistry in 1998, the use of DFT for computational modelling has increased strikingly (see Fig. 1). The use of other first principles methods such as hybrid functionals and the GW approach (see abbreviations for short explanations and chapter 4.5 and 5.3.) have also become increasingly popular, due to the improved computational resources. These methods are also employed in this Thesis. / QC 20110201

This thesis summarizes interrelated simulation studies of three different physical phenomena. The three topics are: simulation of work hardening of materials using dislocation dynamics, investigation of anomalous diffusion in supercooled liquids using molecular dynamics,and kinetic Monte-Carlo simulation of annealing of radiation damaged materials. All three topics require special algorithms in order to enable physically relevant simulations. The author's contributionconsists of development, implementation, and optimization of these algorithms, as well as interpretation of simulation results. / QC 20100805

The kinetics of interstitial hydrogen are of great interest and importance for metal-hydride storage, purification, fusion and fission reactor technology, material failure processes, optical sensors for hydrogen gas and many other technologies. In particular nano-sized materials motivate fascinating applications and scientific questions. If hydrogen is absorbed in vanadium it alters the band structure around the Fermi energy. These modifications of the band structurelead to a change in the absorptance of vanadium which are in first order approximation proportional to the concentration. We present a methodto quantify chemical diffusion of hydrogen in nano-sized materials.The induced changes in the absorptance of vanadium hydride (VHx) thin-films are observed visually and in real-time as a function of position.Concentration profiles and their evolution in time, during chemicaldiffusion, were measured down to a hydrogen content corresponding tojust a few effective monolayers, randomly distributed within VHx. For concentrations reached via phase transitions distinct diffusional behavior was found, where a diffusion-front, a strong concentration gradient, migrates in the direction of the diffusive hydrogen flux. The results show that decreased size strongly influences the energy landscape and reveal different rate limiting steps for absorption and desorption.

Syfte – Studiens syfte var att analysera hur uppkomsten av defekta produkter och omarbeten kan minska i kundorderstyrd montering genom effektivare material- och informationsflöden. Som hjälp till att besvara syftet har det brutits ned i två frågeställningar: I. Vilka möjliga orsaker till defekta produkter och omarbeten kan identifieras i kundorderstyrd montering? II. Hur kan förändringar i material- och informationsflöden minska uppkomsten av defekta produkter och omarbeten i kundorderstyrd montering? Metod – Studiens tillvägagångssätt pågick i en iterativ process och innefattade litteraturstudier samt en fallstudie. I samarbete med det kundorderstyrda företaget JELDWEN Sverige AB i Forserum, genomfördes fallstudien på deras monteringsavdelning. Fallstudien innefattade intervjuer, observationer samt dokumentstudier. Resultatet i studien har uppnåtts genom analysering och jämförelse av insamlad empiri och teori. Resultat – Studien identifierar orsaker till defekta produkter och omarbeten i form av brister i material- och informationsflöden. Orsakerna delas in i fyra huvudrubriker; informationsunderlag, rutiner, personal samt material, som i sin tur bryts ned i elva underrubriker. Samtliga orsaker bidrar till icke värdeskapande aktiviteter och bör därför minskas. En kombination av kanban och kittning är ett förändringsalternativ till nuvarande materialhantering, som säkerställer att rätt material är på rätt plats vid rätt tidpunkt. Informationsunderlag och upplärning bör tydliggöras för att minska osäkerheter hos operatörerna inom montering och därmed minska uppkomst av defekta produkter och omarbeten. Implikationer – I denna studie fastställs att förändringar i material- och informations– flöden kan effektivisera kundorderstyrd montering. För att åstadkomma detta måste bristande orsaker specifikt för varje tillverkande verksamhet identifieras. De förändringsalternativ som presenteras kan kräva vissa investeringar för tillverkande verksamheter och aspekter relaterade till kostnad bör därmed beaktas. Begränsningar – Fallstudien som genomfördes var av enskild karaktär vilket innebär begränsningar i studiens generaliserbarhet. Studien hade till avsikt att identifiera möjliga orsaker till problemet som presenterats, kopplat till material- och informationsflöden. Utifrån denna avgränsning kan väsentliga orsaker utöver detta försummats. / Purpose – The purpose of the study was to analyse how the occurrence of defect products and rework can decrease within customer-order-driven assembly through more efficient material- and information flows. In order to help answering the purpose, the purpose has been decomposed into two questions: I. What possible causes of defective products and rework can be identified in customer-order-driven assembly? II. How can changes in the material- and information flows decrease the occurrence of defect products and rework in customer-order-driven assembly? Method – The approach of the study was iterative and included literature studies and a case study. In cooperation with JELD-WEN Sverige AB in Forserum, which has a high degree customer-order-driven manufacturing, the case study was conducted on their assembly department. The case study included interviews, observations and document studies. The result of the study has been achieved through comparison and analysis of empirical data and theory. Findings – The study identifies the causes of defect products and rework in forms of flaws in material- and information flows. The causes are divided into four headlines; information base, routines, employees as well as material which in turn are broken down into eleven subheadings. All causes contribute to non-value adding activities and should therefore be minimized. A combination of kanban and kitting is an alternative to current strategy for handling the material, which ensures that the right material is in the right place, at the right time. Information base and training should be clarified in order to minimize uncertainty among the operators in the assembly, thus minimizing the occurrence of defect products and rework. Implications – This study establish that customer-order-driven assembly can improve efficiency with changes in material- and information flows. To achieve this, the causes for flaws need to be identified for each specific manufacturing business. The possibilities for change that is presented may require certain investments for the manufacturing business, therefore aspects related to cost should be considered. Limitations – The performed case study had a single character, thus limiting the generalizability of the study. The intention of the study was to identify possible causes to the presented problem, connected to material- and information flows. Due to this limitation, other significant causes may have been neglected.