Background: Rottne Industri is a Swedish heavy machinery manufacturer whose production process is divided in three manufacturing plants. The production takes place in the facilities of Stensele and Lenhovda while the one at Rottne is also used for the final assembly. Ten suppliers provide steel materials to each facility translating to relatively high transportation costs which may be reduced by adopting a more centralized structure. Purpose: The purpose of this paper is to identify the transportation costs between the steel suppliers and the three manufacturing plants at Stensele, Lenhovda and Rottne as well as the freight transportation costs for components from Stensele and Lenhovda to Rottne. Moreover, the research seeks to analyze the difference in transportation costs if Rottne Industri was to centralize all its activities into one single manufacturing facility at Rottne. Finally, the authors aim to identify the environmental cost related to freight transportation in order to evaluate the total transportation cost difference between the two scenarios. Method: The Master thesis focuses on an instrumental case study on a single company. Qualitative and quantitative research methods are used for the necessary data collection to bring up a broader picture of Rottne Industri transportation costs and how it will change in a different organizational structure. Results: The studied company would reduce its freight transportation cost from 2 471 735 SEK of the current decentralized structure to 398 265 SEK of the centralized one. The environmental cost would decrease by 91% (20 420 SEK) due to the decrease of material flow. Therefore Rottne Industri would reduce its total transportation costs by 84% by centralizing its manufacturing structure, for a monetary value estimated at 2 095 860 SEK. However these results contradict part of the theoretical framework concerning the advantages and the disadvantages of centralization and decentralization, as the new centralized structure appears to be more easily manageable while reducing the transportation costs from the different suppliers. Therefore further researches are required as a broader approach on the effects of switch in the organizational structure at Rottne Industri.

All processes in society produce waste. In nature, the waste is normally used as a resource for another process, but in human societies waste is often discarded. These discarded materials end up in places for depositing waste known as landfills. The increase in population, and humans’ tendency to improve their quality of life, has led to an increase in consumption of material. More material consumption means generating more waste, and more waste means bigger landfills. The increasing size of landfills has brought some other issues, such as increased land use and higher environmental impact. However in these landfills a lot of valuable materials are discarded and the concept of landfill mining (LFM) has been proposed in order to solve these issues and use landfills as a possible source of materials. Landfill mining is not yet a common practice, and the first barrier for this is the uncertainty of the amount and value of materials within landfills. The purpose of this study is to prospect the amount of metals in one specific landfill, in this case Gärstad landfill in Linköping, Sweden.  This is a first step to show the feasibility of landfill mining as an alternative way of extracting materials. The study is limited only to metals because they are one of the most important resources in today’s society. The theoretical background of the study is based on material flow analysis (MFA). Two approaches are used to study the materials in the landfill. The first is top-down which studies the flows of materials and the second is bottom-up which studies the stocks of material in the landfill. Based on these approaches the method was developed. First the system boundaries in time and space were defined. Then the amount of waste in landfill was estimated from the two mentioned approaches. In the end the metal content of the waste was estimated. Some criteria are also defined to compare the accessibility of the metals in the landfill. The results of this study show that there is a considerable amount of metals in the landfill, and that ash deposits resulting from incineration are the most interesting source of metals; with iron, aluminium, copper and zinc being the most abundant. The results are presented by type of waste, area of the landfill and accessibility in order to identify the hotspots. Later it is discussed that the method is cheap and fast but highly depends on previous data and available information. Also the metal content of the landfill is compared with natural ores. In the end the metal content of the landfill is evaluated and estimated to be around 3 billion SEK. It shows that aluminium, titanium and copper have the highest value money wise. As conclusion it was shown material flow analysis is a valid way to prospect landfills. But further cost-benefit analysis must be carried out to determine if landfill mining is justifiable. Also some recommendations are proposed to Tekniska Verken in order to facilitate future studies. The first is to develop a systematic way for landfilling different kind of waste and document them. Second is to include metals which have economic potential in the regular sampling from landfill. / Många processer i samhället generar avfall. I naturen används avfallet normalt som en resurs i en annan process, men i människliga samhällen kastas avfallet oftast bort. Bortkastat material hamnar förr eller senare oftast i deponier. Befolkningsökningen och människans tendens till att försöka förbättra sin livskvalitet har lett till en ökad materialkonsumtion. Högre konsumtion genererar mer avfall, och mer avfall kräver större deponier. Växande avfallsanläggningar leder i sin tur till ökad markanvändning och högre miljöpåverkan. I dessa anläggningar finns det emellertid stora mängder värdefullt material deponerat, och från dessa läcker både tungmetaller och metan ut, vilket är skadligt för miljön. Landfill Mining (LFM) har föreslagits som en lösning på dessa problem och avfallsanläggningarna används då även som en möjlig källa till material. Landfill mining är idag inte vanligt förekommande och det huvudsakliga hindret är de många osäkerheterna kring ett sådant projekt, till exempel; hur mycket material finns i deponierna och hur mycket är det värt? Syftet med den här studien är att uppskatta metallinnehållet i en specifik avfallsanläggning, i det här fallet Gärstad avfallsanläggning i Linköping. Detta är ett första steg i att utröna genomförbarheten av LFM som en alternativ resursbas. Studien är begränsad till metaller eftersom dessa håller på att ta slut i jordskorpan och det vore därför intressant att finna nya materialkällor till dessa. Den teoretiska bakgrunden till den här studien är baserad på materialflödesanalys (MFA). Två metoder har använts för att prospektera Gärstad. Dels top-down, som studerar flödet av material, dels bottom-up, som studerar materialförrådet i avfallsanläggningen. Avfallens totalmängd var uppskattad genom att beräkna flödet in och ut från anläggningen. Sedan använde vi tidigare gjorda provtagningar av avfallets metallmängder för att uppskatta metallinnehållet. Slutligen analyserades metallernas tillgänglighet baserad på typ av avfall, och om deponi delområdet var sluttäckt. Resultatet visar att det finns mycket metaller deponerat i Gärstad. Askan från avfallsförbränningen visade sig vara den avfallstyp med rikast metallinnehåll. Järn, aluminium, koppar och zink är de vanligaste förkommande metallerna. Metallkoncentrationen av avfallsanläggningen kan jämföras med naturliga malmer. Värdet av metallerna i Gärstad uppgår till cirka 3 miljarder. Dock är endast 30 % av metallerna tillgängliga med dagens teknik. De största värdena finns enligt följd i aluminium, titan och koppar. För att identifiera hotspots, redovisas resultatet enligt avfallstyp, lokalisering och tillgänglighet. MFA är ett fungerande prospekteringsverktyg för deponier. Metod är billig och snabb men beroende av att det finns tillgänglig data. Innan deponin transformeras till en gruva bör emellertid först en kostnad och nyttoanalys genomföras för att undersöka genomförbarheten vidare. Rekommendationer för att underlätta framtida utgrävningar är att utveckla ett systematiskt sätt att deponera olika typer av avfall och att dokumentera dem. De metaller som har ekonomisk potential bör dessutom inkluderas vid den normala provtagningen av deponerat avfall.

The purpose of this study is to examine how construction logistics work for the ongoing project “Årstastråket” Stage 1, and to identify the logistics problems that the project may have. The aim then is to find solutions to these problems in order to avoid them in the upcoming projects. The study will include delopment of a standard template that can be used in logistics planning of the project. At the beginning of the study a comprehensive literature review of the available literature including reports and research articles was done to obtain a deeper knowledge of the subject in question. The result of this study is based on conducted case studies on the construction site, such as interviews and site visits. The majority of collection in the case study was mainly collected from 11 site visits, which then was supplemented with the information obtained from the interviews. The interviews were conducted with the local manager and supervisor of the project at “Årstastråket” Stage 1. In this study the construction logistics worked generally well, both in terms of transport- and material flow at the construction site. The main logistics problems identified in “Årstastråket” Stage 1 was particularly poor logistics planning of the project at an early stage, lack of visual communication and constant updating of construction site plan alongside project developing. The new developed standard template for logistics planning of the project at an early stage can be used in order to achieve the established goals and make the project even more effective.

PROBLEM - The bobbin friction stir welding (BFSW) process has potential benefits for welding thin sheet aluminium alloy. The main benefits of friction stir welding over conventional thermal welding processes are minimisation of energy usage, no need for consumables, potential for good weld quality without porosity, no fumes, minimal adverse environmental effects (green), minimal waste (lean), and reduced threats to personal health and safety. The BFSW process has further advantages over conventional friction stir welding (CFSW) in the reduction of welding forces, faster welding, and less fixturing. It is especially attractive to industries that join thin sheet material, e.g. boat-building. The industrial need for this project arose from the desire to apply the technology at a ship manufacturing company, INCAT located in Hobart, Tasmania, Australia. However there are peculiar difficulties with the specific grade of material used in this industry, namely thin sheet aluminium Al6082-T6. Early efforts with a portable friction stir welding machine identified the process to have low repeatability and reproducibility, i.e. process-instability. There are a large number of process variables and situational factors that affect weld quality, and many of these are covert. This is also the reason for divergent recommendations in the literature for process settings. PURPOSE - The main purpose of this research was to identify covert variables and better understand their potentially adverse effects on weld quality. Therefore, this thesis investigated the hidden variables and their interactions. Developing this knowledge is a necessity for making reliable and repeatable welds for industrial application. APPROACH - An explorative approach that focused on the functional perspective was taken. An extensive empirical testing programme was undertaken to identify the variables and their effects. In the process a force platform and BFSW tools were designed and built. A variety of machine platforms were used, namely portable friction stir welding, manual milling machine and computer numerical control (CNC) milling machine. The trials were grouped into 14 test plans. These are tool shoulder gap, spindle and travel speed, tool features, machines, tool fixation, machinery, welding direction, plate size (width and dimension), support insulation, tool materials, substrate properties and fixation. For the welded plates besides visual inspection of the weld, current, force, and temperature were measured. The Fourier transform was used to analyse the frequency response of machines. Also the welded samples were tested to the maritime standards of Det Norske Veritas (DNV). A number of relationships of causality were identified whereby certain variables affected weld quality. A model was developed to represent the proposed causality using the IDEF0 systems engineering method. FINDINGS - From these trials six main variables have been identified. These are tool features, spindle speed, travel speed, shoulder gap compression, machine variability, tool and substrate fixation. A rigid system is required for a consistent weld results. Under this condition, full pin features (threads and flats) need to be used to balance the adverse effects of individual features. It has been shown that fabricated bobbin tools with sharp edges can cause cuts and digging thus this feature should be avoided. Additionally, the substrate should have continuous interaction with the tool so the shoulder interference needs to be fixed and well-controlled. It is found that the compression generated by the shoulder towards the substrate helps material grabbing for better tool-substrate interaction. It is also shown that tool entry causes ejection of material and hence an enduring mass deficit, which manifests as a characteristic tunnel defect. The new explanation of the formation, origin and location of this defect has been explained. Material transportation mechanisms within the weld have been elucidated. It is also found that the role of the travel speed is not only to control heat generation but also for replacing the deficit material. Additionally, heat supplied to the weld depends not only on thickness, but also the width of the plate. Different types of machine cause an interaction in the material flow through their controller strategies. Jerking motion can occur at a slow travel speed, which also alters the way material is being transported. The Fourier transform (FFT) has been used to identify the characteristics of good and bad BFSW welds. This has the potential to be expanded for real-time process control. IMPLICATIONS - Tool deflection and positioning, material flow and availability are identified as affecting weld quality through stated mechanisms. The impact is even more severe when involving thin-plate aluminium. For the industry to successfully adopt this technology the process typically needs tight control of shoulder gap, tool strength and stiffness, feature fabrication, substrate and tool fixation. Additionally spindle and travel speed need to be adjusted not only based on the type of materials and thickness, but also the width, type of machine and method of tool entry. ORIGINALITY - New data are presented, which lead to new insights into the welding mechanics, production settings, material transportation and weld defects for BFSW on thin sheet material. The conventional idea that the welding tool has a semi-steady interaction with the substrate is not supported. Instead the interaction is highly dynamic, and this materially affects the weld-quality, especially in the difficult-to-weld material under examination. Factors such as shoulder gap, tool and substrate fixation compliance and machine types emerge as variables that need to be given attention in the selection of process parameters. The causal relationships have been represented in a conceptual model using an IDEF0 system approach. This study has made several original contributions to the body of knowledge. First is the identification of previously hidden variables that effect weld formation for the fixed gap BFSW process. The second contribution is a new way of understanding the material transportation mechanics within the weld. This includes the flow around the pin in the plane of the weld, the vertical transportation of material up the pin, the formation of turbulent-like knit lines at the advancing side, and the formation of tunnel defects. Also included here is a new understanding of how material deficit arises at tool entry and exit, and from flash/chips, and how this contributes to the tunnel weld defect. In addition, new understandings of the role of feed rate have been identified. Related to the material transportation, the work has also identified the importance of an interference fit between the substrate and tool. A third contribution is the identification of the dynamic interaction between tool and substrate. This identifies the important role rigidity plays. Associated with this is the identification of frequency characteristics of the motors under load. The fourth contribution is identification of the specific process settings for the difficult-to-weld material of AL6082-T6. The fifth contribution is the development of a novel method of fabricating bobbin friction stir welding tools as embodied in a patent application.

End products of society (e.g. sewage sludge and incineration ashes) can be used as indicators of the use of chemicals in consumer goods. Through upstream work the sources of substances released from goods may be identified before the emissions reach the end products. This thesis is a result of five studies, of which four were conducted using substance flow analyses (SFA) for silver (Ag), bismuth (Bi) and copper (Cu) reaching sewage sludge. The fifth is an SFA that explores the implications of the presence of As (from CCA-treated wood) in ashes. These studies helped fulfil the specific and overall aims of the thesis; to contribute to the general knowledge on diffuse emissions reflected in end products, by examining emissions of some heavy metals from various societal goods and the implications for end products, in this case sewage sludge and, to some extent, ashes. The results from the studies, of which four had Stockholm as a study object, show the urban flows and accumulated amounts (stocks) of the heavy metals. The largest sources of the metals Ag, Bi and Cu in sewage sludge were identified to be textiles (Ag), cosmetics (Bi) and brake linings (Cu). For As (in CCA-treated wood) and Cu updated SFAs were performed and compared with earlier studies in order to follow the development and changes in flows over time. The current use of the heavy metals studied can also be seen as a loss of resources, and as the metals should ideally be recovered as a part of a circular economy, urban and landfill mining as well as recycling are alternatives that need further exploring. The legislation of chemicals in consumer goods was identified as an important step in handling corresponding diffuse emissions.

The main goal of the thesis is to develop a monitoring instrument for climate policy that is based on the Kyoto Protocol and the IPCC guidelines. The instrument developed is based on a "Full Carbon Accounting" approach which takes into account the carbon flows of the biosphere as well as those related to society's metabolism. Conceptually the analysis is based on the epistemological concept of society nature interaction comprising society's metabolism and colonisation of nature as main starting points. This leads to the empirical concept of material flow analysis. The thesis quantifies the carbon flows and the related uncertainties of the Austrian economy for 1990 for selected areas in a consistent way. The thesis also tries to build up a framework for system of indicators that would allow evaluating climate policy. (author´s abstract)

Purpose: The aim of the study is to investigate how the material flow, of a high-frequent component family, to an assembly line with volume and product mix variations, can be streamlined. In order to examine this, the aim has been divided into two defined queries. Which factors affect the efficiency of the material flow, for a high-frequent component family, to an assembly line?    How can an effective material flow, for a high-frequent component family, be designed? Methodology: Both a case study and a literature study has been performed, in order to answer the queries. Literature in the areas of material and inventory control, transportation and material handling has been studied. The case study, which was carried out at a company, was based on process mapping combined with interviews and observations. Collected data from the case study have been analysed with support of literature. Findings: Different factors that are restricting the efficiency of the material flow for an assembly line has been identified. Unnecessary operations and inefficient material handling resulted in high cycle times for the material flow. Furthermore, the layout and control of the inventory resulted in long lead time and unnecessary inefficient transportations. Inadequate design and integration of the logistic subsystems has shown to be a significant cause, resulting in limited effectiveness of the studied material flow. On this basis, a new design of the material flow has been proposed, where the holistic perspective and integration are central. A new inventory design and a tugger-train transportation solution along a timed route, reduce the material handling and the number of deliveries. In addition, a pull flow system where consumption controls material replenishment, reduces both inventory levels and the number of inventory buffers. Implications: The purpose of the study has been achieved by solving the defined queries. By identifying factors that reduce the effectiveness of the material flow, a more efficient solution can be designed. The study shows that there are several possible improvement opportunities for the studied material flow. However, only one case study was performed, therefore its ability to create scientific value, can be regarded as limited. Recommendations: For further studies, it may be of interest to study several companies with similar problems to be able to draw general conclusions with scientific depth. / Syfte: Studiens syfte är att undersöka hur materialflödet för en högfrekvent komponentfamilj till en volym- och produktmässigt varierad monteringslina kan effektiviseras. För att kunna besvara denna frågeställning har syftet delats in i två problemfrågor: Vilka faktorer påverkar materialflödets effektivitet för en högfrekvent komponentfamilj fram till monteringslina? Hur kan ett effektivt materialflöde för en högfrekvent komponentfamilj utformas? Metod och genomförande: För att kunna besvara studiens syfte har en fallstudie genomförts parallellt med en litteraturstudie. Litteratur inom områdena material- och lagerstyrning, transporter och materialhantering har studerats. Fallstudien, som har genomförts på ett fallföretag, baseras på en processkartläggning i kombination med intervjuer och observationer. Insamlad data från fallstudien har analyserats med stöd från studerad litteratur. Studiens resultat: Faktorer som begränsar ett materialflödes effektivitet fram till monteringslina har identifierats. En stor andel av materialflödets totala cykeltid kunde kopplas till onödiga arbetsmoment och ineffektiv materialhantering. Ytterligare bidrog lagrets utformning och styrning till långa ledtider samt onödiga och ineffektiva transporter. Bristande utformning och integration av materialflödets delar visade sig vara en betydande orsak till begränsningen av dess effektivitet. Med detta som utgångspunkt har en ny utformning föreslagits där helhetsperspektiv och integrering har varit centralt. En ny lagerutformning, i form av materialtorg, samt en transportlösning med trucktåg utefter tidsbestämd rutt, reducerar materialhantering och antalet transporter. Tillämpningen av ett dragande flöde där monteringslinornas efterfrågan styr materialpåfyllnad, reducerar lagernivåer samt antalet buffertlager i materialflödet. Implikationer: Studiens syfte har uppnåtts genom att båda problemfrågorna har besvarats. Genom att identifiera negativa påverkansfaktorer kan förutsättningar skapas för utformningen av ett effektivt materialflöde. Studien visar att det på fallföretaget finns förbättringsmöjligheter för effektivisering av materialflödet fram till monteringslina. Då enbart ett företag studerats kan resultatet av studien och dess förmåga att skapa vetenskapligt värde, ur ett större perspektiv, anses begränsad. Rekommendationer: För vidare studier kan det vara av intresse att studera flera företag med liknande problematik för att öka studiens generaliserbarhet och förmåga att kunna presentera slutsatser med vetenskapligt djup.

Landfilling waste material is still one of the most common methods to take care of waste in a big part of the world. Gaborone, the capital of Botswana located in the southern part of Africa is no different in this way. The major part of all waste is landfilled in Gaborone and there is only a minor part of all collected material that is recycled. One solution that earlier studies suggest is to build a transfer and recycling station in the city of Gaborone that can contribute to a more sustainable waste management. This study aims to identify the major waste streams of recyclable waste and also the major stakeholders that are active in this area through an exploratory study involving interviews, a workshop and a survey. The result of this thesis can hopefully assist in the preparations for such a transfer station. The conclusions of this study are many and contains of both hard facts and also loose ends that can contribute to pursue further studies. The first important result is that all the waste collection companies transports everything they collects to a landfill and it is only recycling organizations that are working with collection and recycling in Gaborone. These recycling organizations are a few but smaller compared to the waste collection companies in collected amounts of material. Besides these collection organizations, Gaborone City Council, the local municipality works with collection of household waste and the collaboration between these three groups that operates in the same environment is very poor. All the interviewed stakeholders showed a positive interest in the transfer and recycling station but there is only a small part of the commercial business in Gaborone that believes in a more serious waste management than landfilling. Despite that one major shopping mall actually sort out recyclables and saves 30% in waste management costs thanks to that. Another issue is the prevailing cultural contradictions that is obvious among the organizations in Gaborone. The last two bigger issues is the tremendously dull political bureaucracy that is appearing in Botswana and also that voices are raised that corruption is great beneath the surface.

Purpose - The purpose of this thesis is to identify factors that have an impact on supermarket inventory levels that supply a manufacturing line and investigate how the impact of these factors can be controlled. In order to fulfill the purpose it was broken down into two research questions.   What factors have an impact on supermarket inventory levels supplying a manufacturing line? 2.      How can the impact of these factors be controlled? Method - To answer the research questions a literature study and a case study were conducted. The empirical findings from the case study and the literature study were used to find the answer to the first research question. The identified factors in the first research question were then analysed with the theoretical framework in order to answer the second research question. Different techniques have been used in order to collect necessary data including documentation studies, interviews, observations and basic training in the case company’s procurement system (GILM).   Findings - Total safety lead time, firm time and shortage impact were discovered during the case study. These factors were not to found during the literature study because they were specific parameters that are predetermined in the case company’s procurement system. Internal material handling and supermarket order quantity were factors also found during the case study. The identified factors are divided after which tool or method that can be used to gain control over the factor. Four different tools have been identified as solutions to gain control over the internal material handling. The factors that only have one identified tool as a solution are either case specific or not attentive in the theoretical framework as the other tools.   Implications - The identified factors from the literature study are considered as common factors that can be applied for companies that have a supermarket inventory. If manufacturing companies are facing problems with their supermarket inventory levels they can increase control by investigating the tools and methods presented in this thesis. Contributions - The factors that were identified during the case study have contributed with new discoveries in the field of study, since there is limited research done in this subject regarding supermarket systems.   Research limitations - More case studies could have been performed at similar companies, in order to investigate how generalizable the answers to both research questions are.

Friction stir welding (FSW) is a relatively new solid-state welding technology invented at The Welding Institute of UK in 1991. It is versatile and has been widely adopted to join various materials. There has been strong research activity on revealing the details of the material flow pattern in the nugget zone induced by the conventional shoulder tool. However, there is insufficient understanding on the aspects of the scroll shoulder tool design and the shoulder flow zone formation utilizing this type of tool. The major objective of this study was to conduct experiments, analyse results and then reveal the shoulder flow zone forming mechanism for the scroll shoulder tool. The method used was to identify the flow pattern in the shoulder flow zone using a ‘marker insert’ technique, and then to suggest the forming mechanism of the shoulder flow zone based on the obtained flow pattern; although the ‘marker insert’ technique has never been used to study the shoulder flow zone flow pattern induced by the scroll shoulder tool. Experiments were conducted to examine the thick sections 6061 aluminium ‘marker insert’ welds, which were welded using a scroll shoulder tool at a range of welding parameters. These were followed by quantifying the mass of the accumulated work piece material within the scroll groove (pick up material-PUM), evaluating the effect of welding parameters on the shoulder flow zone formation, and documenting the shoulder flow zone flow pattern. The major finding was that there is a simple banded structure which forms in a layer to layer manner in the bottom portion of the shoulder flow zone, but it disappears in the top portion of the shoulder flow zone. Accordingly, the forming mechanism of the shoulder flow zone for the scroll shoulder tool was suggested as follows. Firstly, the tool pin is plunged into the work piece; the work piece material is extruded by the pin and pushed up into the scroll groove forming the PUM. Secondly, after the tool shoulder is plunged into the work piece to a certain depth, the scroll groove is fully filled up with the PUM. Finally, during the forward movement of the tool, the central portion of PUM is driven downward by the root portion of the pin and then detaches from the pin (tip portion) in a layer to layer manner. It has also found that the thickness of the shoulder flow zone varies with a thicker on the advancing side than on the retreating side, and there is a positive linear relationship between the mass of PUM and the weld quality. This study has revealed for the first time the forming mechanism of the shoulder flow zone, and has improved the understanding of the shoulder flow zone formation using a scroll shoulder tool. It is recommended that a ‘shoulder-breaking’ technique is developed to break the rotating shoulder suddenly and hence embed it into the work piece during FSW, in which a real-time shoulder-work piece couple could be produced for a better three-dimensional examination of the shoulder flow zone.