De nos jours, les politiques environnementales sont devenues plus strictes envers l’industrie automobile pour réduire les émissions de CO2, donc les structures légères utilisant des matériaux de haute résistance sont d’un grand intérêt. Deux modèles différents EF, à savoir "Solid Refine Model" (SRM) et "Shell Coarse Model " (SCM) ont été développés et sont utilisés comme modèles standard par Faurecia Automotive Seating (Caligny). Le SRM est capable de prédire avec précision le comportement de soudage local, mais malheureusement, en raison de son coût de calcul élevé, le SRM n’est pas adapté à une modélisation de si`ge de voiture complète. D’autre part, le SCM est efficace sur le plan numérique, mais il ne peut pas prédire le comportement de la ligne de soudure. L’objectif de la présente thèse est de développer un modèle EF multi-matèriel dans le logiciel commercial Ls-dyna, qui améliorera le SCM pour permettre une prédiction précise du comportement de la ligne de soudure jusqu’à l’échec avec un coût de calcul raisonnable. Le modèle FE quadrilatère standard est développé et enrichie à l’aide d’une méthode récemment développée appelée "Interpolation Covers Method" (ICM) pour capturer les gradients de la solution avec précision sans raffinement de maillage. Un modèle de matériau élasto-plastique est développé dans le logiciel commercial Ls-dyna qui prend en compte deux matériaux différents à savoir BM et HAZ dans un seul élément de coque. Le modèle généralisé d’endommagement dépendant de l’état de contrainte a été implémenté comme UMAT dans le logiciel commercial Ls-dyna pour prédire l’échec de la ligne de soudure dans SCM. Les différents développements ont permis au SCM de prédire avec précision le comportement complexe de la ligne soudée jusqu’à l’échec, à faible coût de calcul compatible avec les besoins industriels. / Nowadays environmental policies have become more strict towards the automotive industry to reduce the CO2 emission, therefore lightweight structures using high strength materials have become of great interest. Two different FE models namely “Solid Refine Model” (SRM) and “Shell Coarse Model” (SCM) have been developed and are being used as standard models by Faurecia Automotive Seating (Caligny). The SRM is capable to predict accurately the local welding behavior but unfortunately, due to its high computational cost, the SRM is not suitable for a full car seat modeling. On the other hand, the SCM is computationally efficient but it cannot predict the weld line behaviour. The aim of the present thesis is to develop a multimaterial FE model within the Ls-dyna commercial software, which will enhance the SCM to allow the accurate prediction of weld line behavior until failure with a reasonable computational cost. The standard quadrilateral shell FE is developed and enriched using a recently developed method called the “Interpolation Covers Method” (ICM) to capture the solution gradients accurately without mesh refinement. An elasto-plastic material model is developed within Ls-dyna commercial software which takes into account two different materials namely BM and HAZ inside a single shell element. The Generalized Incremental Stress State dependent damage Model has been implemented as a UMAT within Ls-dyna commercial software to predict the weld line failure in SCM. The different developments have allowed the SCM to become able to predict the complex behavior of the welded line accurately until failure, at low computational cost compatible with the industrial needs.

The European Commission adopted the first action plan for the transition to a circular economy in 2015. As a result, the concrete industry’s goal is for all concrete produced in Sweden to be climate neutral by 2045. Cement production is the third-largest carbon dioxide emitter in Sweden and accounts for 90% of concrete’s carbon dioxide emissions. Thus, to lower the climate footprint of concrete, it is necessary to find alternatives to cement. The potential of the use of wood ash in cement as a supplementary cementitious material (SCM) has been investigated in several studies. Due to Sweden's nature and wood industry, a comprehensive study has been done to investigate the possibility of using wood ash as an SCM in Sweden based on availability and efficiency. This work aims to investigate the obstacles and driving forces that concrete producers face when transitioning to a circular economy by partially replacing cement with new potential SCMs. The aim is also to investigate the availability of wood ash generated in Sweden and account for the potential to be used as an SCM. Qualitative semi-structured interviews with open-ended questions were conducted to determine the obstacles and drivers that concrete producers in Sweden face when converting to a circular economy by partially replacing cement with new potential SCMs. The amount of ash produced in Sweden was estimated based on the value of ash content and the potential annual supply of wood fuels in Sweden. In addition, a literature review was performed to investigate the properties of wood ash. The economic and environmental aspects, as well as the fact that the supply of fly ash and slag is likely to decrease in the future form the main driving forces for concrete producers. The obstacles raised by the correspondents were the availability of SCMs, technical barriers, logistics, and standards. The amount of the annual production of wood ash in Sweden is estimated to be between 851 450 and 1 232 950 tons. The chemical characteristics of wood ash did not meet the requirements according to European standard (EN450-1). However, the reviewed articles indicated a potential for wood ash to be used as a supplementary cementitious material due to the indication of some hydraulic and pozzolanic activities. The combination of fly ash and wood ash in concrete is considered viable due to promising results based on mechanical strength. / EU-kommissionen antog den första handlingsplanen för omställningen till en cirkulär ekonomi 2015. Som ett resultat av detta är betongindustrins mål att all betong som används i Sverige ska vara klimatneutral år 2045. Cementindustrin är den tredje största koldioxidutsläpparen i Sverige och står för 90 % av betongens koldioxidutsläpp. För att sänka betongens klimatavtryck är det nödvändigt att hitta alternativ till cement. Potentialen för användningen av träaska i cement som ett alternativt bindemedel har undersökts i flera studier. Med hänsyn till Sveriges natur- och träindustri har en omfattande studie gjorts för att undersöka möjligheten att använda träaska som alternativ bindemedel i Sverige utifrån tillgänglighet och effektivitet. Arbetet syftar till att undersöka de hinder och drivkrafter som betongföretag möter vidövergången till en cirkulär ekonomi genom att delvis ersätta cement med nya alternativa bindemedel. Syftet är också att undersöka tillgången på träaska som genereras i Sverige och redogöra för potentialen att användas som ett bindemedel. Kvalitativa semistrukturerade intervjuer med öppna frågor genomfördes för att fastställa de hinder och drivkrafter som företag inom betongtillverkning i Sverige möter vid en omställning där cement ersätts delvis med nya bindemedel. Mängden aska som produceras i Sverige har uppskattats utifrån värden på askhalt och den potentiella årliga tillgången på trädbränslen i Sverige. Dessutom har en litteraturöversikt genomförts för att undersöka träaskans egenskaper. Drivkrafterna för en omställning till cirkulär ekonomi hos betongindustrier genom delvis ersättning av cement med nya alternativa bindemedel är de ekonomiska och miljömässiga aspekterna samt det faktum att tillgången på flygaska och slagg riskerar att sjunka i framtiden. Hindren som korrespondenterna tog upp var tillgången till alternativa bindemedel, tekniska barriärer, logistik och standarder. Mängden av den årliga produktionen av träaska i Sverige uppskattas mellan 851 450 och 1 232 950 ton. Kemiska egenskaper hos de undersökta träaskorna uppfyller inte kraven enligt europeisk standard (EN450-1). Litteraturöversikten visar dock en potential för träaska att användas som ett alternativt bindemedel till följd av en viss hydraulisk och puzzolanisk aktivitet. Kombinationen av flygaska och träaska i betong anses lönsam på grund av lovande resultat baserade på mekanisk hållfasthet.

Increased competition and globalisation has created new opportunities and challenges for supply chain planning. Implementation of sales and operations planning (S&OP) has thus become vital for companies in order to keep up with competition. One way of facilitating the implementation and assessing the current state of an S&OP process is by the use of maturity models. The purpose of this study is to; (1) evaluate S&OP maturity models through comparative  nalysis and application on a company in the process industry, (2) develop a maturity model  uitable for the process industry, (3) suggest a method for using it, and (4) add to the limited number of case studies describing the S&OP process of companies in different industries. The study has been conducted using a qualitative case study methodology. Qualitative data has been collected through semi-structured interviews with 19 employees from different levels and functions of the organisation in order to develop a complete picture of the S&OP process at the case company. The evaluation of current S&OP maturity models in a case study context has generated a maturity model suitable for the process industry and a qualitative method for maturity assessment. The assessment has also resulted in an in-depth analysis and description of the S&OP process of a company in the pulp and paper industry.

Det finns för närvarande en stark, nationell och internationell, efterfrågan på effektivare bruk av resurser och färskvaror, bland annat från svensk dagligvaruhandel, den svenska regeringen och FN. Naturvårdsverket visar samtidigt att i Sverige så slängs cirka 1.3 miljoner ton mat årligen och att 40% av detta slängs i konsument och butiksled. Detta till trots att dagligvaruhandeln har automatiserade inköpssystem, så kallade Automatiska Ordersystem (AOS). Med utgångspunkt ur dessa system har författarna undersökt, med hjälp av evidensbaserad managementmetodik, intervjuer och observation, Axfoods AOS, Autoorder (AO) utifrån ett inventory managementperspektiv hur systemets nuläge ser ut samt utvecklat en prototyp-modell. Dynamiken av systemet låg fokus, utifrån teoretisk applicering från nutida forskning inom Inventory management. Studien resulterade i teoretisk prototyp som ämnar att bidra till underlag för vidare forskning av AOS. / There’s currently a strong demand, national and international, for a more effective use of resources and perishable goods, among those behind this demand is the Swedish government, the UN and the daily grocery business interest group, Svenskt Näringsliv. At the same time the environmental protection agency in Sweden reports that 1.3 million tons of food are thrown away yearly and that 40% of this originates from the end consumer and the daily grocery business. This problem occurs even though the daily grocery business operates with automated ordering systems (AOS). With this as a starting point the authors have, using evidence-based management methods, interviews and observations, studied the current stat of the Swedish grocery chain Axfood’s AOS, called Autoorder (AO) from an inventory management-based perspective. This resulted in a simple prototype model, where the dynamic modelling of inventory management took center, to act as a foundation for future research within AOS.

The thesis addresses the role of logistic concept in a virtual organization. Theory of virtual organization was complemented by a definition of virtuality and a model of virtual organization was created. Two measurable properties of virtual organizations are used for construction of a 2x2 matrix of centralization – integration giving thus clear view of virtual organizations taxonomy. Duality of hierarchic dimension of network structure and layers of the virtual dimension led to a comprehensive description of virtual enterprises with the aid of newly created 3x3 matrix of virtual layer – hierarchy level. Within this framework are interpreted processes in virtual organization during virtual enterprise’s lifecycle. Dynamic restructuring and stability issues are explained with the aid of the matrixes. A consistent approach of presented virtual organization’s theory gives interpretation of emerging logistic concept. The use and application potential of presented theory is exemplified in development of RFID implementation method for virtual organizations. Attention is paid to RFID costs and benefits analysis under condition of virtual organizing.

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<p>This study investigates the feasibility of using waste glass as a supplementary cementitious material (SCM). By further defining some of the parameters by which waste glass may be incorporated into concrete as a cement replacement, the environmental, economical, and engineering benefits of this material may be realized. Past observations, including the production of alkali silica reaction (ASR) gel, and the lack of pozzolanic reactivity, have limited the acceptance of waste glass as a SCM,</p> <p>Mechanical treatment was used to improve reactivity and provide a particle size at which waste glass performs comparably to ground granulated blast furnace slag and nearly as well as silica fume. At 6.6 µm, the pozzolanic reactivity of waste glass was demonstrated through consumption of Ca(OH)₂ and heat of hydration. Waste glass at a larger particle size (16.5 µm) was as reactive as slag. Use of waste glass at 10% replacement of Portland cement by mass and at a particle size below 100 µm proved useful as a SCM.</p> <p>A relationship between pozzolanic and alkali silica reaction (ASR) was identified with intermediate phases of the reaction present. Calcium silicate hydrates (C-S-H) from the pozzolanic reaction have a Ca/Si ratio of 1.5-2. ASR products generally have a Ca/Si ratio of 0.01-1. The products observed with agglomeration of glass particles had a Ca/Si ratio from 0.5-2. The affects of silica concentration and alkalinity of the solution on the reaction products were explored.</p> <p>A reaction rim was identified around glass agglomerates where fluorescence was observed. The results indicate that ASR can be induced even in low alkalinity cement, and the rate of reaction influences both the characteristics and composition of the reaction product.</p> / Doctor of Philosophy (PhD)

<p>The use of supplementary cementitious materials (SCM) decreases the environmental impact of the cement industry. SCMs are commercial by-products that possess pozzolanic properties. Recycled glass powder, classified as a SCM, when added as a cement replacement reacts with the available lime in the cement to form calcium silicate hydrate (C-S-H) products. In contrast with other SCMs, glass is siliceous and thus the reaction can also cause alkali silica reaction (ASR) which causes expansion and cracking. This study was completed in order to characterize the chemical reactions and their rate using a simplified system that mimics glass particles in hardened cement paste.</p> <p>Silica powder was added to solutions containing calcium hydroxide and/or sodium hydroxide. The rate of dissolution of the silica was monitored as well as the composition of the reaction products. Dissolution rates of silica with varying concentrations of silica, calcium hydroxide and sodium hydroxide, were fitted to the Hixson-Crowell cubic root law. The precipitate composition of the reaction product was represented by means of triaxial plots. It was found that silicate ions enter the solutions containing sodium hydroxide and containing both sodium hydroxide and calcium hydroxide. The rate is proportional to the quantity of sodium ions in the solution and to the pH. Also, higher concentrations of silica generally cause higher dissolution rates. The solutions with a pH of 13.48 and with lower silica concentrations created reaction products that were similar to C-S-H while the solutions with higher pH levels formed ASR after thirty days. The C-S-H prevented further dissolution of the silica. The formation of the ASR reaction products did not prevent further dissolution of the silica and they continued to dissolve until most of the silica had entered the solution.</p> / Master of Applied Science (MASc)