1,720,965 research outputs found
Dynamics of aluminum use in the global passenger car system: Challenges and solutions of recycling and material substitution
Get PDFThis thesis analyzes the relationship between the design of vehicles, end-of-life vehicle (ELV) management, and global material production using aluminum as an example. Vehicle manufacturing, material industries and ELV management face different challenges. An important challenge for vehicle manufacturers is the design of lightweight vehicles to reduce energy use and greenhouse gas (GHG) emissions in the use phase for which an increased use of aluminum of different alloys is an attractive option. The aluminum industry has an interest in reducing energy consumption and GHG emissions, which can be accomplished effectively through recycling. ELV management must be improved to enable the first two systems to use aluminum scrap in a sustainable manner. Today, the sorting of different alloys is limited. As a result of having mixed scrap at the ELV phase and limited opportunities for aluminum refining, there may be a future scrap surplus that cannot be absorbed by the aluminum-recycling sink, which is passenger cars. These three sectors are connected through material flows, and a change in one of the sectors can severely affect the others\u27 options for reaching their goals. This thesis addresses the following questions: 1) How are the dynamics of the global vehicle stock changing the boundary condition for aluminum recycling? 2) What are the most effective interventions to minimize a future aluminum scrap surplus? 3) What are the options for material substitution in vehicles to reduce direct and indirect GHG emissions over time? To answer these questions, a system approach is employed to analyze how these three sectors are linked and to explore options for all sectors to reach their objectives in the long term. This thesis employs global bottom-up stock-driven models of the aluminum cycle. A basic model was used to identify the scrap surplus problem. A refined model with segments, components and alloys resolution combined with a source-sink diagram was used to evaluate different solution options. In addition, a global dynamic fleetrecycling MFA model was developed to simulate the future impacts of material substitutions of conventional steel with high-strength steel (HSS) and aluminum on material cycles, energy use and GHG emissions related to the global passenger vehicle fleet. The main findings in this thesis are: i) a continuation of the current practice of cascadic use would eventually result in a scrap surplus because this practice depends on the continuous and fast growth of the secondary casting stock in the global vehicle fleet, a condition that is unlikely to be met. Model simulation indicated a non-recyclable scrap surplus by approximately 2018\ub15 if no alloy sorting is introduced. The surplus is potentially substantial and could grow to reach a level of 0.4-2 kg/cap/yr by 2050, thereby significantly reducing the option of the aluminum industry to reduce its energy consumption through recycling. ii) Drastic changes in ELV management practices are necessary to make use of the growing scrap flow in the future, including further dismantling and efficient component-to-component recycling, alloy sorting of mixed shredded scrap, and designing recycling-friendly alloys that function as alternative sinks for aluminum scrap. iii) Light-weighting has the potential to substantially reduce global emissions of vehicles (9-18 gigatons cumulative CO2-eq. between 2010 and 2050). In the medium term (5-15 years), global emissions reductions from substituting standard steel with aluminum are similar to those achievable by HSS; however, over a longer term (after 15-20 years), substitution with aluminum can reduce total emissions more effectively, provided that the wrought aluminum will be recycled back into automotive wrought aluminum. The environmental consequences of products in general and passenger cars in particular have led to an increasing awareness of the dependencies between the shaping of vehicles and the shaping of the environment. Governments and intergovernmental bodies have formulated quality goals for the environment, such as the 2-degree target, and have introduced emissions standards, thereby extending the responsibility of automobile manufacturers to the use phase. On the materials side, legislation has been introduced to extend producer responsibility, mainly with the goal of avoiding toxic substances and reducing the amount of waste, as is noted in different end-of-life vehicle (ELV) legislation and directives. The current ELV directives do not sufficiently address the management of material systems as a whole or quality issues related to material recovery. To harmonize ELV management with goals for the global aluminum cycle and its impacts for the environment, it is essential to understand how the above-mentioned systems interact.Has partsPaper 1: Modaresi, Roja; M\ufcller, Daniel B.. The Role of Automobiles for the Future of Aluminum Recycling. Environmental Science and Technology 2012 ;Volum 46.(16) s. 8587-8594 http://dx.doi.org/10.1021/es300648w Copyright \ua9 2012 American Chemical SocietyPaper 2: Rombach, Georg; Modaresi, Roja; M\ufcller, Daniel B.. Aluminium Recycling- Raw Material Supply from a Volume and Quality Constraint System. World of Metallurgy - ERZMETALL 2012 ;Volum 65.(3) s. 157-162Paper 3: Modaresi, Roja; L\uf8vik, Amund Nordli; M\ufcller, Daniel Beat. Component- and Alloy-Specific Modeling for Evaluating Aluminum Recycling Strategies for Vehicles. JOM: The Member Journal of TMS 2014 ;Volum 66.(11) s. 2262-2271., The article is not included due to copyright available at http://dx.doi.org/10.1007/s11837-014-0900-8 Paper 4: L\uf8vik, Amund Nordli; Modaresi, Roja; M\ufcller, Daniel Beat. Long-term strategies for increased recycling of automotive aluminum and its alloying elements. Environmental Science and Technology 2014 ;Volum 48.(8) s. 4257-4265 http://dx.doi.org/10.1021/es405604g Copyright \ua9 2014 American Chemical SocietyPaper 5: Modaresi, Roja; Pauliuk, Stefan; L\uf8vik, Amund Nordli; M\ufcller, Daniel Beat. Global Carbon Benefits of Material Substitution in Passenger Cars until 2050 and the Impact on the Steel and Aluminum Industries. Environmental Science and Technology 2014 ;Volum 48. s. 10776-10784 http://dx.doi.org/10.1021/es502930w Copyright \ua9 2014 American Chemical Society PublisherNTNU SeriesDoctoral thesis at NTNU;2015:11
Dynamics of aluminum use in the global passenger car system: Challenges and solutions of recycling and material substitution [Elektronisk resurs]
No full textThis thesis analyzes the relationship between the design of vehicles, end-of-life vehicle (ELV) management, and global material production using aluminum as an example. Vehicle manufacturing, material industries and ELV management face different challenges. An important challenge for vehicle manufacturers is the design of lightweight vehicles to reduce energy use and greenhouse gas (GHG) emissions in the use phase for which an increased use of aluminum of different alloys is an attractive option. The aluminum industry has an interest in reducing energy consumption and GHG emissions, which can be accomplished effectively through recycling. ELV management must be improved to enable the first two systems to use aluminum scrap in a sustainable manner. Today, the sorting of different alloys is limited. As a result of having mixed scrap at the ELV phase and limited opportunities for aluminum refining, there may be a future scrap surplus that cannot be absorbed by the aluminum-recycling sink, which is passenger cars. These three sectors are connected through material flows, and a change in one of the sectors can severely affect the others' options for reaching their goals. This thesis addresses the following questions: 1) How are the dynamics of the global vehicle stock changing the boundary condition for aluminum recycling? 2) What are the most effective interventions to minimize a future aluminum scrap surplus? 3) What are the options for material substitution in vehicles to reduce direct and indirect GHG emissions over time? To answer these questions, a system approach is employed to analyze how these three sectors are linked and to explore options for all sectors to reach their objectives in the long term. This thesis employs global bottom-up stock-driven models of the aluminum cycle. A basic model was used to identify the scrap surplus problem. A refined model with segments, components and alloys resolution combined with a source-sink diagram was used to evaluate different solution options. In addition, a global dynamic fleetrecycling MFA model was developed to simulate the future impacts of material substitutions of conventional steel with high-strength steel (HSS) and aluminum on material cycles, energy use and GHG emissions related to the global passenger vehicle fleet. The main findings in this thesis are: i) a continuation of the current practice of cascadic use would eventually result in a scrap surplus because this practice depends on the continuous and fast growth of the secondary casting stock in the global vehicle fleet, a condition that is unlikely to be met. Model simulation indicated a non-recyclable scrap surplus by approximately 2018±5 if no alloy sorting is introduced. The surplus is potentially substantial and could grow to reach a level of 0.4-2 kg/cap/yr by 2050, thereby significantly reducing the option of the aluminum industry to reduce its energy consumption through recycling. ii) Drastic changes in ELV management practices are necessary to make use of the growing scrap flow in the future, including further dismantling and efficient component-to-component recycling, alloy sorting of mixed shredded scrap, and designing recycling-friendly alloys that function as alternative sinks for aluminum scrap. iii) Light-weighting has the potential to substantially reduce global emissions of vehicles (9-18 gigatons cumulative CO2-eq. between 2010 and 2050). In the medium term (5-15 years), global emissions reductions from substituting standard steel with aluminum are similar to those achievable by HSS; however, over a longer term (after 15-20 years), substitution with aluminum can reduce total emissions more effectively, provided that the wrought aluminum will be recycled back into automotive wrought aluminum. The environmental consequences of products in general and passenger cars in particular have led to an increasing awareness of the dependencies between the shaping of vehicles and the shaping of the environment. Governments and intergovernmental bodies have formulated quality goals for the environment, such as the 2-degree target, and have introduced emissions standards, thereby extending the responsibility of automobile manufacturers to the use phase. On the materials side, legislation has been introduced to extend producer responsibility, mainly with the goal of avoiding toxic substances and reducing the amount of waste, as is noted in different end-of-life vehicle (ELV) legislation and directives. The current ELV directives do not sufficiently address the management of material systems as a whole or quality issues related to material recovery. To harmonize ELV management with goals for the global aluminum cycle and its impacts for the environment, it is essential to understand how the above-mentioned systems interact. Has parts Paper 1: Modaresi, Roja; Müller, Daniel B.. The Role of Automobiles for the Future of Aluminum Recycling. Environmental Science and Technology 2012 ;Volum 46.(16) s. 8587-8594 http://dx.doi.org/10.1021/es300648w Copyright © 2012 American Chemical Society Paper 2: Rombach, Georg; Modaresi, Roja; Müller, Daniel B.. Aluminium Recycling- Raw Material Supply from a Volume and Quality Constraint System. World of Metallurgy - ERZMETALL 2012 ;Volum 65.(3) s. 157-162 Paper 3: Modaresi, Roja; Løvik, Amund Nordli; Müller, Daniel Beat. Component- and Alloy-Specific Modeling for Evaluating Aluminum Recycling Strategies for Vehicles. JOM: The Member Journal of TMS 2014 ;Volum 66.(11) s. 2262-2271., The article is not included due to copyright available at http://dx.doi.org/10.1007/s11837-014-0900-8 Paper 4: Løvik, Amund Nordli; Modaresi, Roja; Müller, Daniel Beat. Long-term strategies for increased recycling of automotive aluminum and its alloying elements. Environmental Science and Technology 2014 ;Volum 48.(8) s. 4257-4265 http://dx.doi.org/10.1021/es405604g Copyright © 2014 American Chemical Society Paper 5: Modaresi, Roja; Pauliuk, Stefan; Løvik, Amund Nordli; Müller, Daniel Beat. Global Carbon Benefits of Material Substitution in Passenger Cars until 2050 and the Impact on the Steel and Aluminum Industries. Environmental Science and Technology 2014 ;Volum 48. s. 10776-10784 http://dx.doi.org/10.1021/es502930w Copyright © 2014 American Chemical Society Publisher NTNU Series Doctoral thesis at NTNU;2015:11
Estimation of pollutant loads transported by runoff for today and future scenarios by using a GIS model : Case study, Luleå city centre
No full textUrbanisation has produced an increase in impervious surfaces which is reducing the amount of storm water infiltration and increasing rapidly surface runoff. Urban storm water carries a variety of pollutants from activities on residential, commercial, and industrial land. There are several objectives that must be accomplished to meet the European Water Framework Directive, however to date, no clear guidelines or legislation have been established regarding storm water quality. Transition to sustainable approaches such as Best Management Practices (BMPs) and Water Sensitive Urban Design (WSUD) is essential, especially in the face of an uncertain future with climate changes affecting the urban water system. The concentration and types of contaminants depends greatly on the type and intensity of activities and land use. By knowing the size of a catchment and the type of land use, it is possible to predict storm water run-off quantity. Subsequently, using generalised pollutant concentrations, it is possible to estimate the pollutant loads transported by the run-off to the receiving water bodies. The main objective of this study was to investigate the annual pollutant mean loads transported from a catchment to receiving water bodies. The study furthermore aimed at estimation of effects of climate change on pollutant loads. The case study was performed in the Luleå city centre located in the north part of Sweden with a cold climate condition. To perform the study, a GIS model was created with a total area of 230 hectares divided into 19 sub-catchments by using a Digital Elevation Model, an Orthophoto map, a storm water network map and a field study. Within each sub-catchment different kinds of land use were identified: roads, housing areas, parking areas, and green areas. As a result of this mapping, the pollution generated from the catchments was estimated as monthly and annual loads for today condition and also for future in periods of 2041-2070 and 2071-2100. Studied pollutants were heavy metals, such as Pb, Zn, Cu, and Cd and some other pollutants including COD, Tot-P, Tot-N, and TSS. While this study roughly estimates the pollutant loads transported to near water bodies, there is a need for further studies to evaluate the values of the water bodies and the legislation to allow the BMP and WSUD recommendations to be realized. Further more it is needed to consider climate change effects. The result of this study shows that climate change will have positive effects in case of pollutants loads but it is needed to perform further study on that since there might be some factors which was ignored and could affect the condition.Validerat; 20101217 (root
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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