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  • 501.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Issa, Issa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    Consultant Geologist, Erbil.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Mystery of Mosul Dam the most Dangerous Dam in the World: Problems Encountered During and after Impounding the Reservoir2015In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 5, no 3, p. 47-58Article in journal (Refereed)
    Abstract [en]

    Mosul dam was built on the River Tigris northern part of Iraq during the period 25th January, 1981 and finished on 24th July, 1986. The foundation of the dam lies on the Fatha Formation. This formation is composed of alternating beds of marls, limestone, gypsum and clay. The beds of this formation are highly karstified. After impounding, several sinkholes developed within the vicinity of the dam site. The surface expression of the sinkholes suggests that they are caused by underground collapse.The appearance of the downstream sinkholes is most likely related to fluctuations in the tail water level of the main dam during operation of the dam and the downstream regulating reservoir. In addition, water seepage also was noticed in various areas indicating the dissolution of gypsum and anhydrite from the foundation. During the period February-August, 1986 the dissolution intensity ranged from 42 to 80 t /day.

  • 502.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    Erbil, Iraq.
    Mosul Dam: A Catastrophe yet to unfold2017In: Engineering, ISSN 1947-3931, Vol. 9, no 3, p. 263-278Article in journal (Refereed)
    Abstract [en]

    Mosul Dam is multipurpose earth fill dam 3.4km long, 113m in height and its storage capacity reaches 11.11 km3 of which 2.95 km3 dead storage. The dam is located on the River Tigris in the northern part of Iraq about 60km north west Mosul city. The dam was built on highly karstified alternating beds of gypsum, marl and limestone. The dam was operating in 1986 and since then, seepage problems started due to the solubility of the gypsum beds, presence of karstification and the effect of the local groundwater aquifer. To stop the seepage insensitive grouting program was put to ensure the stability of the dam. Despite the injection of large quantities of grouting material, it did not stop the seepage. The situation became worse in 2014 when ISIS occupied the dam area and grouting operations were halted. Recent evaluation of the conditions indicates that the dam is in its worst conditions.

    The failure models of the dam indicate that 6 million people will be affected, and 7202km2 of land will be inundated. It is believed that to stop this catastrophe, grouting operations should be continued intensively to elongate the span life of the dam. As a permanent solution, another dam should be built downstream Mosul Dam so that it can take the wave of Mosul Dam in case of its failure.

  • 503.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    Department of Geology, University of Kurdistan, Hewler.
    Risk Management Concepts in Dam Safety Evaluation:Mosul Dam as a Case Study2017In: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 11, no 7, p. 635-652Article in journal (Refereed)
    Abstract [en]

    Gradual shift has been observed lately of dam safety procedures from the conventional technical based towards a widerscope of risk management procedure based on risk analysis. The new approach considers the likelihood level of occurrence of a multitude of hazards and the magnitude of the resulting possible consequences in case of failure using rational cause and effect arguments. Most dam owners are shifting towards the use of the new risk based procedures; and even governments themselves are moving towards formalizing the new trend. Legislations in the United States were promulgated [1] after serious dam failures and the adoption of stringent levels of scrutiny led such federal dam owners to pioneer in this field and in developing the concepts and methods required. The corner stone in risk analysis is the definition of the potential modes that may lead to failure and assessment of the likelihood levels of their occurrence and possible category of the consequences which, after thorough evaluation, will shape thedecision making. This type of analysis was applied to Mosul Dam as a case study and resulted in definite recommendations.

  • 504.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan K.
    University of Kurdistan, Howler, KRG, Iraq and Private Consultant Geologist, Erbil, Iraq .
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Climate Change: Consequences on Iraq’s Environment2018In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 8, no 3, p. 43-58Article in journal (Refereed)
    Abstract [en]

    Iraq as a country is now suffering from Climate Change Impacts in similar or even worse ways than many other countries of the world. The manifestations of these climate changes are being felt in global warming, changes to weather driving elements and sea level rise. Increasing temperatures, declining precipitation rates and changed distribution patterns together with increasing evaporation are causing water stress in Iraq. However, they trigger other changes in a sort of chain reaction; such as droughts, desertification and sand storms. Iraq is not even safe from the consequences of sea level rise where the southern part of the Tigris- Euphrates delta is threatened by inundation and Iraq’s ports and sea coast line are endangered by such projected rise. So far the agricultural sector in Iraq has been hit very badly by the reduced water availability for arable lands; whether rain fed lands as in the northern part, or irrigated lands using the declining discharges of the Tigris and Euphrates Rivers as in the southern and middle parts. These discharges have already been additionally strained by the unfair sharing practiced by Turkey from which most of the two rivers’ water resources originate. The present negative climate change trends seem to be continuing in the future as it is obvious from all projections and studies being performed so far. Loss of cultivable land to desertification, recurrent droughts and sand storms and declining agriculture are the pattern of change in Iraq’s already fragile environment; and this will result inevitably in much more distress for the population in the future and will lead to social unrest. These will add to the great pressures facing all future governments unless the government takes protective planning and solutions.

  • 505.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    University of Kurdistan, Howler, KRG.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Climate Change: The Uncertain Future of Tigris River Tributaries’ Basins2018In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 8, no 3, p. 75-93Article in journal (Refereed)
    Abstract [en]

    Global warming is hitting all parts of the world for the last fifty years due to Global Climate Change and it is expected to continue in the future in an increasing trend unless the present mode of CO2 emission is limited or reversed. This is manifested in the rising temperature over land and the changes induced in the general weather circulation patterns over land and oceans. The Tigris River catchment as most of other parts in the world is suffering from increased temperatures and reduced precipitation contributing to reduced water resources elements all over it and reduction of the river stream flow itself. Studies using the soil and water assessment tool SWAT were performed on the five Tigris River tributaries basins in Iraq in order to assess these impacts. This paper summarizes the results of those studies, the characteristics of each of the five basins, and illustrates the application of SWAT as a tool for future predictions. Moreover, it explains in more details the work done on one of the basins as an example, summarizes the results of the five studies and then analyzes these results and discusses the expected future outcomes. The final conclusion which can be drawn is that severe shortage in all water resources elements will occur over the five basins and the Tigris River stream flow will suffer a considerable decline. This situation demands that policy makers in Iraq should take steps immediately to improve water and soil management practices to try and reduce as much as possible the expected damage that will hit all water using sectors.

  • 506.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    University of Kurdistan, Erbil.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Is Mosul Dam the Most Dangerous Dam in the World?: Review of Previous Work and Possible Solutions2017In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 9, no 10, p. 801-823, article id 79510Article in journal (Refereed)
    Abstract [en]

    Mosul Dam is an earth fill dam located on the Tigris River in North Western part of Iraq. It is 113 m in height, 3.4 km in length, 10 m wide in its crest and has a storage capacity of 11.11 billion cubic meters. It is, constructed on be- drocks which consist of gypsum beds alternated with marl and limestone, in cyclic nature. The thickness of the gypsum beds attains 18 m; they are in- tensely karstified even in foundation rocks. This has created number of prob- lems during construction, impounding and operation of the dam. Construc- tion work in Mosul Dam started on January 25th, 1981 and started operating on 24th July, 1986. After impounding in 1986, seepage locations were recog- nized. The cause of seepage is mainly due to: 1) The karsts prevailing in the dam site and in the reservoir area. 2) The existence of gypsum/anhydrite rock formations in the dam foundation alternating with soft marl layers and wea- thered and cavernous limestone beddings. 3) The presence of an extensive ground water aquifer called Wadi Malleh aquifer, which affects considerably the ground water regime in the right bank. The dissolution intensity of the gypsum/anhydrite ranged from 42 to 80 t/day which was followed by a noti- ceable increase in the permeability and leakages through the foundation. In- spection of the dam situation in 2014 and 2015 indicates that the dam is in a state of extreme unprecedentedly high relative risk. In this work, possible so- lutions to the problem are to be discussed. It is believed that grouting opera- tions will elongate the span life of the dam but do not solve the problem. Building another dam downstream Mosul Dam will be the best protective measures due to the possible failure of Mosul Dam, to secure the safety of thedownstream area and its’ population.

  • 507.
    Adamo, Nasrat
    et al.
    Private Consultant Engineering, Norrköping, Sweden.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    University of Kurdistan, H awler, Iraq.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Badush Dam: A Unique Case of Flood WaveRetention Dams Uncertain Future and Problematic Geology2019In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 11, no 4, p. 189-205Article in journal (Refereed)
    Abstract [en]

    Badush Dam is a partially completed dam and a unique case of flood reten- tion dams. Its intended main function is to perform flood protection once in its lifetime; that is if Mosul Dam would collapse. In such a case, the Badush dam would temporarily store the whole flood wave and route it safely to the downstream. For this end, the bulk of the reservoir is left dry, while the re- maining  volume  at  the  lower  part  which  is  intended  for  power  eneration does  not  give  an  economic  justification  for  building  the  full  height  of  the dam. The short duration of the intended use as a protection dam has led to relaxing many design assumptions which have raised concerns over the dam integrity.  The  current  controversy  rages  now  over  whether  to  continue  the construction of the dam as it was first designed or to change all that in view of the similar site geology of Mosul Dam. Mosul dam foundations suffer at the moment from the severe continuous dissolution of the soluble materials in its foundation  leading  to  continued  maintenance  grouting  of  that  foundation. This paper gives an overview of the history of Badush dam, its current design and what new equirements which are needed if it is to replace Mosul Damitself.

  • 508.
    Adamo, Nasrat
    et al.
    Private Consultant Engineering, Norrköping, Sweden.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    University of Kurdistan, Howler, KRG, Iraq. Private Consultant Geologist, Erbil, Iraq.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Mosul Dam: Geology and Safety Concerns2019In: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 13, no 3, p. 151-177Article in journal (Refereed)
    Abstract [en]

    Mosul Dam is an earth fill dam located on the River Tigris northern part of Iraq. The capacity of its reservoir is 11.11 billion cubic meters which makes it the fourth biggest dam in the Middle East. From geological perspective, the dam is located on double plunging anticlines. The rocks of the site are mainly composed of highly jointed and karistified alternating beds of limestones, gysum and marls, since the impoundment of the reservoir seepage of water was recognized under the foundation of the dam. To stop or minimize the seepage, intensive grouting operations were conducted. Recent investigations and evaluation of the conditions of the dam indicate that it is in a critical situation. In this paper, consequences of the dam failure are discussed and possible solutions are given.

  • 509.
    Adamo, Nasrat
    et al.
    LTU team.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sissakian, Varoujan
    University of Kurdistan, Howler, KRG.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    The Future of the Tigris and Euphrates Water Resources in view of Climate Change2018In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 8, no 3, p. 59-74Article in journal (Refereed)
    Abstract [en]

    Climate Change which results from global warming is affecting the Tigris and Euphrates River basins in similar ways to all other parts of the Middle East and the East Mediterranean region. This contains also what is historically known as the “Fertile Crescent”, which is threatened in the same way as the other parts and may disappear altogether. The climate change is manifested in increased temperatures, reduced precipitation in addition to erratic weather patterns and decreased annual stream flow of the two rivers. These phenomena have been markedly noticed during the last decades of the last century. Studies show that these changes are linked also to the variations of North Atlantic Pressure Oscillation (NAO) induced by Global Climate Change. Modeling studies on the future trends, in trying to define the magnitude of the changes to be anticipated, reveal clearly that these negative impacts are continuous in the future. But, the widely ranging projections and interpretations of different sources depict an uncertain future for the basin’s climatic conditions and indicate theneed for further modeling studies to reach more definitive conclusions. These studies show however, a drastic decline of the Euphrates and Tigris water resources at the end of this century by something like (30 to 70) %; as compared to their resources in the last three decades of the previous century. The wide variations in the projections emphasize the need of further future work on this matter. All in all, these studies should bring alarm to all responsible governments in the region to resort to long range planning by adopting rational policies in soils and water resources management to mitigate the adverse impacts that could hit human societies in these events.

  • 510. Adamo, Nasrat
    et al.
    Sissakian, Varoujan K.
    University of Kurdistan, Howler, KRG. Private Consultant Geologist, Erbil, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Elagely, Malik
    Private consultant, Baghdad, Iraq.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Comparative Study of Mosul and Haditha Dams in Iraq: Different Construction Materials Contribute to Different designs2018In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 8, no 2, p. 71-89Article in journal (Refereed)
    Abstract [en]

    Mosul and Haditha Dams are built on relatively weak foundations. Both of these foundations suffer from extensive karsts which had demanded intensive foundation treatment works among other design precautions. The karst forms; however, are of different origins, activities, nature and shapes. The foundation treatment in both dams was done mainly by constructing deep grout curtains along with other secondary grouting works. Reducing uplift pressure under the dam and cutting down on seepage losses were the major considerations in these works. An additional important requirement in Mosul Dam was to reduce the permeability of the rock formation in the foundations to such a low limit that it can stop the dissolution of gypsum beds present there. This objective; unfortunately, failed due to the lithological composition of this foundation and the presence of many brecciated gypsum beds, which could not be treated successfully. This had resulted in a comprehensive grouting maintenance program which continuous up to date with the everlasting danger of dam failure. On the other hand, in Haditha dam no such complication occurs as the dam had its foundations mainly in limestone. Proper investigation and good planning and performance of the grouting works in this dam contributed highly to its success. Selecting the deep grout curtain as anti-seepage measure in Mosul Dam was not a very wise decision and constructing a positive cutoff in the form of diaphragm wall could have been the proper choice. Good and deep understanding of all geological data can contribute to the success of a dam design or, otherwise it may lead to unsafe one.

  • 511. Adamo, Nasrat
    et al.
    Sissakian, Varoujan K.
    University of Kurdistan, Hewler, KRG. Private Consultant Geologist, Erbil, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Badush Dam: Controversy and Future Possibilities2018In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 8, no 2, p. 17-33Article in journal (Refereed)
    Abstract [en]

    Badush Dam is believed to be the first dam in the world which is designed to protect from the flood wave which could result from the collapse of another dam; in this case Mosul Dam.  Badush Dam construction was started in 1988 but it was stopped two years later due to unexpected reasons. From that time on many attempts were made to resume construction without success. Its value was stressed in a multitude of studies and technical reports amid conflict of opinions on how to do this.  The original design of the dam as a protection dam was intended to have a large part of the reservoir empty to accommodate the volume of the expected flood wave for only a few months during which time it’s content are released in a controlled and safe way to the downstream. The lower part of Badush Dam which has a limited height continues before and after this event to act as a low head power generation facility. Among the later studies on the dam, there were suggestions to introduce changes to the design of the unfinished dam which covered the foundation treatment and also asked for constructing a diaphragm in the dam. A long controversy is still going on with many possibilities but with no hope to reach a final solution soon. Any rational solution must consider both Badush Dam and Mosul Dam together as the safety issue involves both of them. This paper may be seen in six paragraphs. The first three describe in brief the history, the outline design and foundation treatment of the dam, therefore, setting the background to follow the conflicting views over its purpose and future which is discussed in the following two paragraphs. The final paragraph is devoted to discussion and our conclusions.

  • 512. Adamo, Nasrat
    et al.
    Sissakian, Varoujan K.
    University of Kurdistan, Hewler. Private Consultant Geologist, Erbil, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Elagely, Malik
    Private consultant, Baghdad, Iraq.
    Comparative Study of Mosul and Haditha Dams, Iraq: Foundation Treatments in the Two Dams2018In: Journal of Earth Sciences and Geotechnical Engineering, ISSN 1792-9040, E-ISSN 1792-9660, Vol. 8, no 2, p. 53-70Article in journal (Refereed)
    Abstract [en]

    Mosul and Haditha Dams are built on relatively weak foundations. Both of these foundations suffer from extensive karsts which had demanded intensive foundation treatment works among other design precautions. The karst forms; however, are of different origins, activities, nature and shapes. The foundation treatment in both dams was done mainly by constructing deep grout curtains along with other secondary grouting works. Reducing uplift pressure under the dam and cutting down on seepage losses were the major considerations in these works. An additional important requirement in Mosul Dam was to reduce the permeability of the rock formation in the foundations to such a low limit that it can stop the dissolution of gypsum beds present there. This objective; unfortunately, failed due to the lithological composition of this foundation and the presence of many brecciated gypsum beds, which could not be treated successfully. This had resulted in a comprehensive grouting maintenance program which continuous up to date with the everlasting danger of dam failure. On the other hand, in Haditha dam no such complication occurs as the dam had its foundations mainly in limestone. Proper investigation and good planning and performance of the grouting works in this dam contributed highly to its success. Selecting the deep grout curtain as anti-seepage measure in Mosul Dam was not a very wise decision and constructing a positive cutoff in the form of diaphragm wall could have been the proper choice. Good and deep understanding of all geological data can contribute to the success of a dam design or, otherwise it may lead to unsafe one.

  • 513.
    Adamson, Fanny
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Carlsson, Erik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Implementering och uppföljning av Lean inom en flygplatsverksamhet: En fallstudie utförd hos Swedavia Umeå Airport2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The number of flight passengers have during the last years increased and there is nothing indicating that the trend won’t continue in the same direction. From airport owners, airlines and through environmental and standard requirements the demands are increasing which creates incentives for airports to work with continuous improvements to meet the demands. One way to work with continuous improvements is by using Lean philosophy. In the literature, there are several development areas with Lean that many organizations encounter. For example, lack of management commitment, unclear goals and strategies and lack of training for employees. Lean is today used by airports around the world, however there are few studies that addresses Lean within an airport environment.

    This thesis was conducted as a case study at Swedavia Umeå Airportwith the purpose of exploring how airport organizations can implement and follow-up Lean initiatives. Through interviews and observations, a cause-and-effect diagram was created to visualize the work with continuous improvements. This diagram was then compared with a conceptual framework designed from a literature study in order to see how the continuous improvement work could be developed. In addition, a literature study was conducted focusing on follow-up and measurement, which provided the basis for recommendations regarding follow-up of improvement work.

    The result showed that the airport experienced similar development areas as earlier studies with Lean in different contexts had shown, for example, the importance of management commitment and establish clear goals. At the case company a foundation were found regarding continuous improvement work with assigned Lean-leaders, Lean tools and a willingness within the organization to work with continuous improvements. The recommendations intended to direct the willingness towards the same goal, structure information flow within the organization and develop the work with continuous improvements. Umeå Airportis recommended to establish clear goals, introduce meetings within the groups and among Lean-leaders and that management should request improvement work. In addition, recommendations how follow-up could be managed is made by arguing how current measurements could be used to monitor continuous improvements. The recommendations made could be applied to other organizations with similar experience with Lean regardless of context.

  • 514. Adamsson, Carl
    Användning av gråberg från Zinkgruvan som ballast till sprutbetong2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 515. Adamsson, Ola
    et al.
    Berglund, Anton
    Kartläggning och förbättring av internt materialflöde: En studie på BAE Systems Hägglunds vid avdelningen Prototyp & Skrov2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 516. Adasme, Claudia
    Unga människor och framtiden: en uppsats om unga människors framtidssyn ur ett familjebildningsperspektiv2008Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 517.
    Addie, G.R.
    et al.
    GIW Industries Inc..
    Roudnev, A.S.
    Weir Minerals North America.
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Weir Minerals North America2007In: Hydrotransport 17: the 17th International Conference on the Hydraulic Transport of Solids ; [7 - 11 May 2007, Cape Town, South Africa, South African Institute of Mining and Metallurgy, 2007, p. 205-218Conference paper (Refereed)
    Abstract [en]

    The Hydraulic Institute has completed the task of developing a new ANSI/HI standard 12.1-12.6 (2005) for rotodynamic (centrifugal) slurry pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of the different slurry pump types and contains an extensive section on pump and slurry definitions. The effect of slurry on pump performance is covered along with the pumping of froth. Reference is also made to ANSI/HI standard 9.6.7 (2004), which contains a new method for pump performance correction when handling viscous fluids. Classification of slurry services is established and then is used to determine limitations on velocities and total head per pump in order to obtain acceptable wear performance. The new service class, head per stage and other limits are directly related to capital and other cost considerations that will affect solids transport system economics. The writers review the contents of the new standard, highlight the main points, and discuss the reason for the slurry classification, corresponding limits and expected implications, particularly with respect to operating costs of the pumps in solids transport systems

  • 518.
    Addie, Graeme
    et al.
    Engineering and Research and Development, GIW Industries Inc.
    Carstens, M.
    GIW Industries Inc..
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Visintainer, R.
    GIW Industries Inc..
    Whitlock, L
    Hydraulic Test Lab., GIW Industries Inc.
    Pipeline design characteristics of some industrial paste-like slurries2005In: Conference Proceedings - First Extractive Metallurgy Operators' Conference, The Australian Institute of Mining and Metallurgy , 2005, p. 147-154Conference paper (Refereed)
    Abstract [en]

    There is a wide variety of industrial pastes or non-settling slurries pumped in mining, dredging and reclamation projects as products, refuse and tails. The types and/or names of some of the common ones are alumina red mud, phosphate clays, tar sands mature fine tails, tar sands (CT) consolidated clays and fly ash. The pipeline performance or friction of these varies dramatically with the type, its concentration and the particulars of the actual slurry making it difficult to select pumping equipment and to design associated pipelines. The GIW Hydraulic Laboratory in Grovetown Georgia has tested a number of these slurries over the last 30 years for various mining customers. Where available in the public domain and/or where permission has been obtained, the results of those tests are presented in this paper in a form usable for pipeline and pump system designers and users.

  • 519.
    Addie, Graeme R.
    et al.
    GIW Industries Inc..
    Roudnev, Aleksander S.
    Weir Minerals North America.
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    The new ANSI/HI centrifugal slurry pump standard2007In: Journal of the South African Institute of Mining and Metallurgy, ISSN 0038-223X, Vol. 107, no 6, p. 403-409Article in journal (Refereed)
    Abstract [en]

    The Hydraulic Institute has completed the task of developing a new ANSI/HI standard 12.1-12.6 (2005) for Rotodynamic (Centrifugal) Slurry Pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of the different slurry pump types and contains an extensive section on pump and slurry definitions. The effect of slurry on pump performance is covered along with the pumping of froth. Reference is also made to ANSI/HI standard 9.6.7 (2004), which contains a new method for pump performance correction when handling viscous fluids.Classification of slurry services is established and then is used to determine limitations on velocities and total head per pump in order to obtain acceptable wear performance. The new service class, head per stage and other limits are directly related to capital and other cost considerations that will affect solids transport system economics. The writers review the contents of the new standard, highlight the main points, and discuss the reason for the slurry classification, corresponding limits and expected implications, particularly with respect to operating costs of the pumps in solids transport systems.

  • 520.
    Addie, Graeme R.
    et al.
    GIW Industries Inc..
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    A first slurry standard and some implications for paste application2007In: Paste 2007: proceedings of the tenth International Seminar on Paste and Thickened Tailings / [ed] Andy Fourie; Richard Jewell, Perth: Australian Centre for Geomechanics, 2007, p. 153-162Conference paper (Refereed)
    Abstract [en]

    The Hydraulic Institute has just completed the task of developing a new ANSI/HI standard on Rotodynamic (Centrifugal) Slurry Pumps covering nomenclature, definitions, applications, and operation. The standard provides examples of all the different types of pumps available and has an extensive section on definitions. Slurries and their effect on performance and wear are covered. A slurry service class is established which then is used to limit velocities and head produced per pump to give acceptable wear. A special section deals with mechanical seals and a new method for determining flange loads is presented and guidelines are given for commissioning, start-up etc.The head limits and the performance derating are of special interest when centrifugal slurry pumps are applied to thickened tailings and paste-like slurries. For Newtonian liquids, the Hydraulic Institute's Viscosity Correction Method (ANSI/HI 2004) provides a procedure widely used for viscous effects on the performance. For the homogeneous flow of viscous slurries, the new slurry standard refers to an applicable viscosity to use with the method and to "consult the pump manufacturer for guidance regarding non-Newtonian slurry pump performance."Experimental performance results are presented here and applied to the viscosity correction method for a simulated tailings product slurry characterized by a fully sheared yield stress of about 100 Pa, evaluated from pipeline data. The pump was a GIW-LCC type three-vane all metal unit with a 0.3m-diameter impeller having an open shroud with a simple auger-like inducer. Results are also given for an underground hydraulic fill product characterized by a Newtonian kinematic viscosity which is 1300 times that for water. The different results obtained here point out the strong influence the rheological behavior has on the choice of pump size and the power requirement.

  • 521.
    Addle, Graeme R
    et al.
    GIW Industries Inc..
    Sellgren, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Design, selection, sizing and control considerations for cyclone feed slurry pumps1999In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 104, no 3, p. 233-239Article in journal (Refereed)
    Abstract [en]

    Cyclone feed centrifugal slurry pumps in semi-autogenous grinding (SAG) mill and other cyclone feed circuits see coarse size slurries at high concentrations that can result in high wear if the pump is not designed, selected, sized and operated correctly. The high proportion of static head of the normal cyclone feed circuits usually results in a relatively flat system curve which in conjunction with the typically flat slurry pump curve results in large changes in operating flow with small changes in system head. When this is combined with the normal (or abnormal) fluctuations in the output from the mill upstream of the pumps, any shortcomings in the pump control system and/or matching of the pump means large fluctuations in flow and increased wear. This difficulty could be corrected by continuous variations in speed. A means of control by which the speed is changed in an appropriate way is suggested here. In this case then the pump-input power, the known water performance of the pump and the system flow, can be used to calculate an effective pump discharge pressure. By comparison with a calculated system head, the pump speed can be regulated such that the pressures are equal and the system stable for any practical variation of incoming flow or specific gravity.

  • 522. Adebahr, Malin
    et al.
    Gogman, Josefine
    Upplevd effekt av mikropauser med rörelser hos personer med stillasittande kontorsarbete2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 523.
    Adelbrun, Alina
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Vad innebär lagreformen för organdonation?: En studie av de rättsliga följderna av den statliga utredningen2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I samband med den statliga donationsutredningen förväntades en lagreform som skulle öka donationsfrekvensen. En sådan reform uteblev dock och det finns anledning att ifrågasätta varför det blev på det sättet. Arbetets syfte har varit att ta reda på orsaken till den uteblivna lagreformen i donationsfrågor efter donationsutredningens slut, samt att uppmärksamma de ändringar som trots allt har införlivats. För att kunna besvara frågeställningarna har den rättsdogmatiska metoden använts, med rättskälleläran som grund, för att fastställa gällande rätt före och efter den statliga utredningen om organdonationer. Utredningen visar att efter att utredningsbetänkandet och de dithörande remissvaren hade analyserats kunde det konstateras att lagförslagen inte kunde införas på grund av oförenlighet med grundlagen. Vissa av donationsutredningens förslag har dock ändå införlivats och beslut om en ny förordning gällande donationsregistret har fattats.

  • 524. Adeleke, E.
    et al.
    Cizmesija, A.
    Oguntuase, James
    Persson, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Pokaz, D.
    On a new class of Hardy-type inequalities2012In: Journal of inequalities and applications (Print), ISSN 1025-5834, E-ISSN 1029-242X, Vol. 2012, no 259Article in journal (Refereed)
    Abstract [en]

    In this paper, we generalize a Hardy-type inequality to the class of arbitrary non-negative functions bounded from below and above with a convex function multiplied with positive real constants. This enables us to obtain new generalizations of the classical integral Hardy's, Hardy-Hilbert's, Hardy-Littlewood-P\'{o}lya's and P\'{o}lya-Knopp's inequalities as well as of Godunova's and of some recently obtained inequalities in multidimensional settings. Finally, we apply a similar idea to functions bounded from below and above with a superquadratic function.

  • 525. Adell, Martin
    THz tomography2002Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In THz tomography the information found in the reflection and transmission of a pulse is interpreted to determine the structure of the refractive index of a sample. The pulses considered are short, time durations in the order of [fs], with the result that the pulses will have a large bandwidths. The frequency distributions of the pulses are centered around a frequency is in the THz region. The reflection from a sample can give information about change in refractive index,n. A step like profile of n can be recognized by the number of reflections, where the time delay between the reflections reveals the thickness of a region if n is known or vice versa. The reflections from such a structure also contain information about the difference of n at either side of an interface. A reflection against a region with larger n than the region in which the pulse is traveling will cause a phase shift 180 degrees, while the opposite relation of refractive indexes at an interface conserves the phase. The fraction of reflected power at an interface is also a measure of the difference in magnitude of n at either side of the interface. The complex part, or the absorption frequencies, of the refraction index can also be recognized by THz tomography. The decay in amplitude of the transmission of a pulse through a sample indicates that there is absorption in the frequency range of the pulse. A broadening in time of the transmitted pulse indicates a frequency dependence of n. A pulse broadening of this kind is either caused by absorption of certain frequencies or the simple fact that different frequency components travel with different speed in a medium where the refractive index is a function of frequency. In order to show that these properties are found in the reflection and transmission of a pulse different functions for the refractive indices have to be analyzed. This analysis is done by assuming a value of n and solving the wave equation for that particular situation where the initial conditions are given by the initial pulse. Before solving the wave equation it has to be verified that the expression of the wave equation used is valid for the chosen form of n. Once the wave equation is found an appropriate numerical method can be used to obtain a solution. The solution gives the reflection and transmission of the pulse and the shapes of these for the chosen n are found and the above mentioned properties are verified.

  • 526. Adelsberg, David
    Sedumtak2013Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
  • 527. Adelsund, Kristian
    Svavels påverkan på trevägskatalysatorer samt regenerering av förgiftad katalysator2005Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 528. Adermalm, Johan
    Genom upplevelseproduktion skapa förutsättningar för barn 6-12 år att bli goda värdskapsutövare2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This following document is the result of my Bachelor thesis. It deals with some of the threats in Strategi2020, which is a public strategic document that has been developed by Svensk Turism AB and its partners in order to double the total revenue of the growing tourism in Sweden by the year of 2020. The one threat that I have focused my research on is the fact that Swedes may not be considered very hospitable and welcoming to tourists. This, in my opinion is an overlooked issue that just recently caught the attention of Swedish entrepreneurs as a competitive advantage towards other businesses. I believe that in order to become more competitive as a tourism destination and as a global business partner Swedes in general need to be more hospitable. In this paper I have focused my research on how to make the general Swede a better host and a stronger ambassador of their own country by working directly with Swedish children at the ages between 6 and 12 years old. I have based my strategy development plan on two successful environmental projects that have been developed for the same specific age group as described above. I have later on combined the methods I have found in these strategies with theories in experience production. This in order to create a method for the public school system in Sweden to teach the children the importance of tourism and how good hostmanship can help the nation to become a better tourist destination and thereby reach the financial goals set by Strategy2020.

  • 529. Adermalm, Roger
    et al.
    Nilzon, Per
    Att leva med diabetes mellitus typ II: en litteraturstudie2001Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 530. Aderot, Linn
    et al.
    Rosendal, Therese
    Förvärv eller operationell leasing: Varför frångås den strategiska inriktningen?2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A company needs assets to be able to achieve competitiveness and growth. These can be financed either by leasing or acquisitions. Depending on a company’s strategic direction, the financing methods can be variously beneficial. A company can be divided into three different levels based on what time perspective that is in focus regarding decision-making. The purpose of this study is to explain why a company chooses a financing method that is not in line with the strategic direction. The study is a qualitative research where a company from the construction industry was examined. Data was gathered through interviews and the respondents were selected to represent three different levels within the selected company. The results imply that all levels of the company are characterized by an administrative perspective. Overall, the responses indicate a low strategic awareness and that the administrative level have a high authority. The company waives from the strategic direction because of different limitations. These restrictions can either be administrative-, cost-, supply-, or time based. The main advantage with operating lease was considered to be the risk factor. The main advantage with acquisitions was the cost factor. To sum up, the administrative level is most restricted in their work, which reflects on the choice of financing method.

  • 531.
    Aderot, Tommy
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Effektiva offentliga upphandlingar för ökad industrialisering inom anläggningsbranschen: En fallstudie på Trafikverket2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I Sverige står de offentliga upphandlingarna för cirka 625 miljarder kronor per år. För att styra de offentliga upphandlingarna mot politiska mål har regeringen tagit fram en nationell upphandlingsstrategi som bland annat beskriver hur offentliga upphandlingar kan främja innovation och alternativa lösningar för att öka produktiviteten. Inom exempelvis anläggningsbranschen har utredningar visat en låg ökning i produktivitet jämfört med den tillverkande industrin. En stor del av anläggningsarbetena upphandlas av offentliga beställare vilket innebär att potential finns att påverka entreprenörernas produktivitet. För att öka produktiviteten föreslås industrialiserade metoder. Slutprodukterna är dock komplexa och för att minska komplexiteten anser litteraturen att både processer och produkter bör standardiseras.

    Syftet med studien var att undersöka hur offentliga upphandlingar kan främja industrialisering inom anläggningsbranschen och utfördes som en fallstudie på myndigheten Trafikverket. Trafikverket upphandlar årligen för cirka 40 miljarder kronor och är därmed Sveriges största beställare av infrastruktur. Trafikverkets Beställar- och upphandlarstrategi innehåller bland annat strategin industriell produktion. I och med detta finns potential att påverka entreprenörerna att använda industriella produktionsmetoder och därför ansågs myndigheten lämplig att undersöka i den här studien. Tolv upphandlingar undersöktes och datainsamlingen utfördes genom 35 kvalitativa intervjuer med upphandlare, projektledare och entreprenörer. Intervjuerna analyserades genom kodning för att underlätta jämförelse samt för att möjliggöra kvantifiering av svaren.

    En slutsats är att oavsett om upphandlingen är tänkt att främja industrialisering eller inte, försöker entreprenörerna alltid arbeta industriellt. Detta visas i två fall där entreprenören ansåg att förutsättningar för industrialisering saknas, trots detta användes industriella arbetsmetoder. Vidare är den största påverkande faktorn för industrialisering paketering av liknande objekt eftersom detta skapar återupprepningseffekter. Faktorer som däremot hindrar industrialisering är Trafikverkets regler och styrning, konstruktionens utformning samt variationer i omgivningen. Intervjuerna visade även varierande kunskapsnivå gällande begreppet industriell produktion samt en diskrepans mellan Trafikverkets och entreprenörernas uppfattning gällande vilka främjande faktorer som upphandlingarna skapat.

    Förbättringsförslagen består av tre delar och handlar om att skapa intern samsyn gällande begreppet industriell produktion genom att standardisera arbetssättet och arbeta med ständig utveckling genom erfarenhetsåterföring. Vidare bör Trafikverket beakta interna förutsättningar för att exempelvis öka entreprenörens frihetsgrader samt utreda vilka verksamhetsområden samt vilka konstruktioner som är mer lämpliga för industrialisering. Slutligen rekommenderas att inkludera entreprenören tidigt i processen, exempelvis genom marknadsdialoger för att öka kunskapsnivån genom erfarenhetsåterföring från tidigare projekt samt för att skapa dialog kring begreppet industriell produktion.

  • 532. Adeteg, Linda
    Ledningssystem för informationssäkerhet: kartläggning av SFK Certifiering AB åtaganden för att uppnå ackreditering enligt ISO 27006:20072008Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 533.
    Adewumi, Oluwatosin
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Liwicki, Foteini
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Liwicki, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Conversational Systems in Machine Learning from the Point of View of the Philosophy of Science—Using Alime Chat and Related Studies2019In: Philosophies, ISSN 2409-9287, Vol. 4, no 3, article id 41Article in journal (Refereed)
    Abstract [en]

    This essay discusses current research efforts in conversational systems from the philosophy of science point of view and evaluates some conversational systems research activities from the standpoint of naturalism philosophical theory. Conversational systems or chatbots have advanced over the decades and now have become mainstream applications. They are software that users can communicate with, using natural language. Particular attention is given to the Alime Chat conversational system, already in industrial use, and the related research. The competitive nature of systems in production is a result of different researchers and developers trying to produce new conversational systems that can outperform previous or state-of-the-art systems. Different factors affect the quality of the conversational systems produced, and how one system is assessed as being better than another is a function of objectivity and of the relevant experimental results. This essay examines the research practices from, among others, Longino’s view on objectivity and Popper’s stand on falsification. Furthermore, the need for qualitative and large datasets is emphasized. This is in addition to the importance of the peer-review process in scientific publishing, as a means of developing, validating, or rejecting theories, claims, or methodologies in the research community. In conclusion, open data and open scientific discussion fora should become more prominent over the mere publication-focused trend.

  • 534.
    Adey, E.A.
    et al.
    University of Exeter.
    Shail, R.K.
    University of Exeter.
    Wall, F.
    University of Exeter.
    Varul, M.
    University of Exeter.
    Whitbread-Abrutat, P.
    Eden Project.
    Baciu, C.
    University of Babes-Bolyai.
    Ejdemo, Thomas
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Lovric, I.
    University of Mostar.
    Udachin, V.
    Institute of Mineralogy.
    Corporate social responsibility within the mining industry: case studies from across Europe and Russia2011In: Proceedings of the Aachen International Mining Symposia (AIMS): 5th International Conference – Sustainable Development in the Minerals Industry (SDIMI 2011), Aachen, 14-17 June 2011, Aachen: Aachen University , 2011, p. 153-170Conference paper (Refereed)
    Abstract [en]

    Responsible mining requires a company to engage with local communities throughout all stages of their operations, from exploration phases through to post mining planning. Assessment of current and potential future social impacts allows a company to maximize the positive impacts they can have on a community, whilst minimizing negative social impacts from mining. Initiating and upholding effective stakeholder relations are key to a company`s ability to obtain and maintain their "social license" to operate. The level of interaction between mining companies and stakeholders, including local communities, varies substantially between and within countries. As part of the EU funded Framework 7 "ImpactMin" Project (Impact Monitoring of Mineral Resources Exploitation), we have examined the level of community engagement in mining and related processing industries at sites across Europe, including Romania (Rosia Montana), Sweden (Kristineberg), the UK (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These sites reflect different stages in mining and therefore reveal a diverse range of issues and differing levels of community engagement. Our aim has been to focus not only on how practice varies, but also to try to explain the complex reasons behind the relationships that exist between mining companies and different stakeholders. Findings of questionnaires undertaken across the sites (between June - October 2010), and results of interviews and focus groups of different people linked to the mining industry, will also be discussed. The expectations that "mining" communities have of their local mining company vary substantially, directly relating to what the community believes the mine company owes them. These examples highlight that the notion of corporate social responsibility in the mining sector in Europe and Russia is fluid and changes according to the differing expectations and goals of stakeholders. We will present highlights of initial results. For example, Rosia Montana Gold Corporation, in Romania, is trying to reopen closed state gold mines. They have seen international media attention relating to campaigns by NGOs to oppose the mines reopening. Our results will help reveal what samples of different stakeholder groups really think of the mines reopening. This example contrasts distinctly with a mine in Kristineberg, Sweden, where Kristineberg village was built alongside the mine. There are now distinct issues felt within the community due to the decline in the number of people employed at the mine.

  • 535. Adey, J
    et al.
    Jones, R
    Palmer, D W
    Briddon, P R
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Erratum: Degradation of Boron-Doped Czochralski-Grown Silicon Solar Cells [Phys. Rev. Lett., 93, 055504 (2004)]2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 16, p. 169904-Article in journal (Other academic)
  • 536.
    Adey, J.
    et al.
    School of Physics, University of Exeter.
    Jones, R.
    School of Physics, University of Exeter.
    Palmer, D.W.
    School of Physics, University of Exeter.
    Briddon, P.R.
    School of Natural Science, University of Newcastle upon Tyne.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Degradation of boron-doped Czochralski-grown silicon solar cells2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 5, p. 055504-1Article in journal (Refereed)
    Abstract [en]

    The formation mechanism and properties of the boron-oxygen center responsible for the degradation of Czochralski-grown Si(B) solar cells during operation is investigated using density functional calculations. We find that boron traps an oxygen dimer to form a bistable defect with a donor level in the upper half of the band gap. The activation energy for its dissociation is found to be 1.2 eV. The formation of the defect from mobile oxygen dimers, which are shown to migrate by a Bourgoin mechanism under minority carrier injection, has a calculated activation energy of 0.3 eV. These energies and the dependence of the generation rate of the recombination center on boron concentration are in good agreement with observations.

  • 537.
    Adey, J.
    et al.
    School of Physics, University of Exeter.
    Palmer, D.W,
    School of Physics, University of Exeter.
    Briddon, P.R.
    School of Natural Science, University of Newcastle upon Tyne.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Theory of boron-vacancy complexes in silicon2005In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 71, no 16, p. 165211-Article in journal (Refereed)
    Abstract [en]

    The substitutional boron-vacancy BsV complex in silicon is investigated using the local density functional theory. These theoretical results give an explanation of the experimentally reported, well established metastability of the boron-related defect observed in p-type silicon irradiated at low temperature and of the two hole transitions that are observed to be associated with one of the configurations of the metastable defect. BsV is found to have several stable configurations, depending on charge state. In the positive charge state the second nearest neighbor configuration with C1 symmetry is almost degenerate with the second nearest neighbor configuration that has C1h symmetry since the bond reconstruction is weakened by the removal of electrons from the center. A third nearest neighbor configuration of BsV has the lowest energy in the negative charge state. An assignment of the three energy levels associated with BsV is made. The experimentally observed Ev+0.31 eV and Ev+0.37 eV levels are related to the donor levels of second nearest neighbor BsV with C1 and C1h symmetry respectively. The observed Ev+0.11 eV level is assigned to the vertical donor level of the third nearest neighbor configuration. The boron-divacancy complex BsV2 is also studied and is found to be stable with a binding energy between V2 and Bs of around 0.2 eV. Its energy levels lie close to those of the V2. However, the defect is likely to be an important defect only in heavily doped material.

  • 538.
    Adhikar, Subhra
    et al.
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Powai.
    Nurni, Viswanathan
    Dusane, Rajiv Onkar
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Powai.
    Thermodynamic analysis of gas phase chemistry in hot wire chemical vapor deposition of a-Si:H and μc-Si:H2006In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 362, no 9-20 Spec Iss., p. 928-932Article in journal (Refereed)
    Abstract [en]

    Gas phase reactions amongst filament-generated radicals play a crucial role in growth and properties of films deposited by hot wire chemical vapor deposition (HWCVD) technology. Gas phase species of interest are SiH4, H2, Si, H, SiH3, SiH2 and SiH. Partial pressures of these species for different sets of deposition conditions have been determined from the standard Gibbs free energy data. Equilibrium concentrations of the film forming precursors have been determined. The effect of the various process parameters on the equilibrium concentration of the precursors has been studied. H, Si and SiH are found to be the dominant species in gas phase above a filament temperature of 2300 K. However SiH3 and SiH2 concentration peaks are between 1900 and 2300 K, of the filament temperature

  • 539.
    Adjizian, J.J.
    et al.
    Department of Chemistry, University of Sussex, Falmer, Brighton.
    Latham, Chris
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Briddon, P.R.
    Electrical, Electronic and Computer Engineering, University of Newcastle upon Tyne.
    Heggie, M.I.
    Department of Chemistry, University of Sussex, Falmer, Brighton.
    DFT study of the chemistry of sulfur in graphite, including interactions with defects, edges and folds2013In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 62, p. 256-262Article in journal (Refereed)
    Abstract [en]

    Sulfur has several roles, desirable and undesirable, in graphitization. We perform density functional theory calculations within the local density approximation to define the structures and energetics of sulphur in graphite, including its interactions with point defects and edges, in order to understand its role in the later stages of graphitization. We find sulphur does not cross-link layers, except where there are defects. It reacts very strongly with vacancies in neighbouring layers to form a six coordinate split vacancy structure, analogous to that found in diamond. It is also highly stable at basal edge sites, where, as might be expected, the size and valency of sulfur can be easily accommodated. This suggests a role for sulphur in stabilizing graphene edges, and following from this, we show that sulfur dimers can open, i.e. unzip, folds in graphite rapidly and exothermically.

  • 540.
    Adjrad, M.
    et al.
    University of Leeds.
    Aguado, L.E.
    Advanced Digital Institute.
    Daly, M.
    University of Leeds.
    Kemp, A.
    University of Leeds.
    Junered, Marcus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Lindström, J.
    Luleå tekniska universitet.
    Akos, Dennis
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Mangin, F.
    France Developpement Conseil.
    Interference monitoring for GNSS bands in indoor and urban environments2007In: Proceedings of the 20th International Technical Meeting of the Satellite Division of the Institute of Navigation: ION GNSS 2007, Institute of Navigation, The , 2007, Vol. 4, p. 1211-1220Conference paper (Refereed)
    Abstract [en]

    A collaborative research project between the University of Leeds and Luleå University of Technology, Sweden, has taken place aiming to characterize the man-made noise in urban and indoor environments in the Galileo allocated frequency bands: E5 (1191.795 ± 25.575 MHz), E6 (1278.75 ± 20 MHz), and L1 (1575.42 ± 16 MHz), obviously, also covering the GPS L1 and L5 bands. This project has been co-funded by the European GNSS Supervisory Authority (EGSA), with funding from the 6th Framework Program of the European Community for research and technological development. The project includes the development of two receiver systems: the first instrument is based on the use of a spectrum analyzer (SA-based instrument), a wideband GNSS antenna, and a front-end capable of capturing each Galileo band separately using appropriate filtering and switches. The second instrument addresses the issues of cost and portability, providing interference detection and alarm triggering without the need for complex instrument. This is accomplished using low cost components in a small form factor where the instrument is based on a core GNSS front-end. This instrument will only cover the L1/E1 band. The interference measurement is obtained by combining the information from the automatic gain control (AGC) voltage that controls the AGC amplifier gain and the spectrum analysis of the analogue-to-digital converter (ADC) output raw data. The AGC information will be very important for detecting the presence of wideband interference signals where this will be difficult using spectrum analysis (in contrast to the case to narrowband interference signals). Control and data logging from both instruments are performed using a laptop computer where the spectrum analyzer traces and the FE-based instrument data are recorded for offline analysis via a suite of MATLAB® scripts. This paper describes the spectrum survey conducted at various indoor and urban locations, operationally significant to GNSS, in the North of the UK. The survey sites were selected to obtain geographically diverse measurement results and provide a general representation of the spectral environment. In addition, the temporal variation of man-made noise (MMN) is considered, this latter being correlated with the human activity at the measurement site, by performing the measurements day and night, weekdays and weekends.

  • 541. Adlerborn, J
    et al.
    Björk, L
    Westman, Anna-Karin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Larker, H
    Particulate-reinforced ceramics densified by glass encapsulated HIP1991In: Hot isostatic pressing: Theory and applications / [ed] R J Schaefer; Melvin Linzer, Materials Park, Ohio: ASM International, 1991, p. 211-216Conference paper (Refereed)
  • 542. Adlercreutz, Axel
    Autenticitet i upplevelsemiljöer: dynamiken mellan dåtid och nutid på Dieselverkstaden, Jumbo Hostel och Gröna Lund2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 543. Adling, Erik
    et al.
    Berglund, Daniel
    Fjärravläsning: nya tider nya krav?2005Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 544. Adling, Erik
    et al.
    Berglund, Daniel
    RFID och den personliga integriteten2004Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 545.
    Admir, Dzamastagic
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Armin, Dzamastagic
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Bankers utlåning till mikroföretag: En kvalitativ studie om hur handläggare bearbetar och bedömer mjuk information2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Banks make the claim that the use of soft information is important in the credit assessment of opaque businesses. However, unlike hard information, precise guidelines on what soft information loan officers are expected to collect and report, and how it should be processed are not imposed by banks. Therefore, the purpose of this study is to explore what soft information loan officers consider to be of importance in the credit assessment and then to compare how it differs individually between loan officers. Further, we analyze how individual loan officers process soft information to make it sensible and usable. We examine the following factors likely to affect the approach of the loan officer: experience and knowledge, uncertainty associated with the case, and factors of time. The study is characterized by a qualitative research strategy. Semi-structured interviews including seven loan officers with different levels of expertise in commercial lending were conducted. Using the critical incident technique, we investigate how loan officers perceive their information processing and evaluation of soft information in real lending situations where hard information is insufficient or non-existent. In contrast, we also investigate how loan officers process soft information and evaluate cases that are perceived as less uncertain or more general in nature. The results show that obvious differences are present between individual loan officers and the emphasis that is being put on various soft information signals. However, soft information related to the business owner´s professional background, the presented business plan/idea, and the industry which the business operates in, seems to be of greater importance. Signals in the likes of how a business markets itself and attitude towards growing the business, are mostly of lesser to no importance. Other signals that were identified varied greatly in importance across our sample of loan officers. Next, we find that individual loan officers differ in how they go about processing different types of soft information. The results indicate that more experienced loan officers exert a greater effort in collecting and reflecting on soft information about the business owner, but are also more inclined towards processing and evaluating information about the industry in an intuitive matter, which in our case differs from inexperienced loan officers. Lower effort from inexperienced loan officers to process soft information about the business owner seems to be linked to the constraints of distinguishing and interpreting relevant soft information signals. Further, the results indicate that loan officers’ effort to be attentive towards soft information is affected by the level of uncertainty the loan officer experiences with a case. Finally, it appears as though individual loan officers assume different cognitive styles in which a combination of both analytic and intuitive methods are used in order to process soft information, rather than strictly relying on one approach. 

  • 546.
    Adolfsson, Daniel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Cementitious properties of steelmaking slags2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The present study is directed towards the use of steelmaking slags as raw material for sulphoaluminate belite cement (SAB). Another important objective was to characterise the cementitious properties of phases in ladle furnace slag (LFS) specifically the calcium aluminates. Mayenite (C12A7) is considered one of the most important calcium aluminate in LFS, and since comparatively limited data on the kinetic properties of this phase are available, it was decided to study C12A7 more closely with regard to both particle size and temperature sensitivity. The behaviour of high-temperature reactions of tested SAB mixtures was investigated using thermogravimetric analysis coupled with a quadrupole mass spectrometer. Mineralogical observations were carried out with x-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results proved that steelmaking slags have the potential to work as raw material, since sulphoaluminate (C4A3 S ) along with polymorphs of dicalcium silicate (C2S) and ferrite phase (C4AF) were detected after firing at 1200ºC in an air atmosphere. The hydration properties of the specimens were analysed through conduction calorimetry, and compressive strength of specimens hydrated for 2 and 28 days. The compressive strength was in accordance with that suggested in the literature for slow hardening SAB cement. Both mixtures tested behaved the same with regard to heat development as well as the amount of ettringite (AFt) formed during the first 24 hours of the hydration. The formation of AFt was characterised with both differential scanning calorimeter (DSC) and XRD. The crystallographic distribution in LFS samples was quantified using Rietveldanalysis. Calorimetric studies were performed at 20, 25 and 30°C in order to calculate the activation energy of hydration and thereby to suggest a kinetic model for tested compositions within this temperature interval. In addition to heat of hydration, compressive strength tests were completed on mortar prisms of LFS, and LFS in a blend with ground granulated blast furnace slag (GGBFS) which hydrated for 2, 7 and 28 days. Both compositions reached acceptable early strengths, whereas, after 28 days hydration, the blend was superior to neat LFS. Related activation energy was according to the Avrami-Erofeev model determined to 58 kJ/mol for the LFS and 63 kJ/mol for the blend. Corresponding calorimetric studies at the same temperatures were performed on a fine and coarse size fraction (Fraction A and Fraction B) of a synthesised C12A7. The purity was confirmed by XRD, and the hydraulic behaviour was investigated in excess water with respect to the dissolution. The apparent activation energy was calculated to 33 and 79 kJ/mol, respectively, for Fractions A-B using the Avrami-Erofeev model. From the model, it was also concluded that the acceleration period can be ascribed to a phase-boundary controlled mechanism. The principal calcium aluminate hydrates obtained were C2AH8 and C2AH7.5, and it was further observed that C12A7 is accompanied by an anomalous setting behaviour much like monocalcium aluminate (CA), and that the decomposition of C2AH8 to C2AH7.5 develops more slowly with higher surface area, specifically at 20 and 30°C.

  • 547. Adolfsson, Daniel
    Steelmaking slags as raw material for sulphoaluminate belite cement2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The present work was undertaken as part of the research in the Minerals and Metals Recycling research centre, MiMeR. The course of the thesis is attributed to metallurgical slags from the steelmaking industry and the possible use of such by-products as raw material for sulphoaluminate belite cement (SAB). Implementing steel slags into the production of cement could contribute to the steel industry's possibility of increasing the recirculation. In addition to the previous objective, the introduction of slag into the cement manufacturing can also facilitate the reduction of carbon dioxide emissions as well as lowering the overall energy consumption during the manufacturing. The reason for this is that the SAB system enables the reduction of the lime saturation factor (LSF) which in turn implies that less limestone is needed in the raw meal. Additionally, the firing temperature can be reduced by about 100-150°C, since dicalcium silicate and sulphoaluminate are formed already at approximately 1200-1250°C. In any event, one should remember that this is not intended to be a final solution for the recycling of slag, nor a replacement for already accepted cement materials. A number of applications currently exist where ordinary Portland cement (OPC) is used, but in cases where the OPC could be replaced with other type of cements, e.g. SAB cement, the possibility of using residues material in cement applications is increased. Considering the clinker covered within this work, possible applications are those where slow hydraulic properties are suitable. The behaviour of high temperature reactions of tested mixtures was investigated using thermogravimetric analysis coupled with a quadrupole mass spectrometer. Mineralogical observations were carried out with x-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results proved that steelmaking slags have the potential to work as raw material, since sulphoaluminate along with polymorphs of dicalcium silicate and ferrite phases were detected after firing at 1200 ºC in an air atmosphere. The hydraulic properties of the specimens were analysed through conduction calorimetry, XRD, differential scanning calorimetry (DSC) as was the mechanical strength of the specimens when hydrated for 2 and 28 days. The compressive strength was in accordance with that suggested in the literature for slow hardening SAB cement. Both mixtures tested behaved the same with regard to heat development as well as the amount of AFt formed during the first 24 hours of the hydration.

  • 548. Adolfsson, Daniel
    et al.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Cementitious phases in ladle slag2011In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 82, no 4, p. 398-403Article in journal (Refereed)
    Abstract [en]

    Ladle slag is an internal by-product generated within the steelmaking industry during the refining of steel. The realisation of beneficial inherent properties of ladle slag as a binder supplement or substitute material is believed to be advantageous with respect to both economy and environment for steelmakers. For this reason, the current study has focused on highlighting the properties of ladle slag that are pertinent to the formation of calcium aluminate hydrates. Three fractions of ladle slag, two of which were based on different slag formers, have been characterised using XRF, XRD and calorimetric analysis. Commonly known hydraulic minerals such as mayenite, tricalcium aluminate and dicalcium silicate were detected during analysis. An important aspect in the utilisation of ladle slag is the slag handling methodology. Therefore, this study also highlights and discusses the need to reconsider slag handling procedures concerning unnecessary exposure to weathering and the possible need for further processing of the slag in order to better employ the inherent hydraulic properties of this material.

  • 549. Adolfsson, Daniel
    et al.
    Menad, Nourreddine
    Viggh, Erik O.
    Bureau de Recherches Géologiques et Minières, Orléans.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hydraulic properties of sulphoaluminate belite cement based on steelmaking slags2007In: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 19, no 3, p. 133-138Article in journal (Refereed)
    Abstract [en]

    Based on modified Bogue calculations, steelmaking slags were combined in order to produce a belite-rich clinker activated with sulphoaluminate. The experiments were conducted on two different mixtures based on steelmaking slags together with additives, namely MixA and MixB. The objective of the present study was to investigate the hydraulic properties of the specimens, using conduction calorimetry, X-ray diffraction and differential scanning calorimetry, and also to measure the mechanical strength of the specimens when hydrated for 2 and 28 days. The compressive strength was satisfactory in relation to the estimated compositions. Both mixtures behaved the same with regard to heat development as well as the amount of ettringite formed during the first 24 h of the hydration.

  • 550. Adolfsson, Daniel
    et al.
    Menad, Nourreddine
    Viggh, Erik O.
    Cementa AB, Malmö.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Steelmaking slags as raw material for sulphoaluminate belite cement2007In: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 19, no 4, p. 147-156Article in journal (Refereed)
    Abstract [en]

    In the present study, slags from the steelmaking industry are described and considered as a potential raw material within the field of sulphoaluminate belite cement. The objective of the study was to investigate the possibility of using a substantial amount of steelmaking slags as raw meal in the manufacture of a sulphobelitic clinker. A further aim was to compare the influence of different slags in relation to the formation of sulphoaluminate and the other clinker phases required. The behaviour of high temperature reactions was investigated by using thermogravimetric analysis coupled with a quadrupole mass spectrometer. Mineralogical observations were carried out through X-ray powder diffraction, and scanning electron microscopy. Three different mixtures and a single ladle slag were prepared using modified Bogue calculations, which are characterised by the assessment of a potential phase composition in order to produce belite-rich cement activated with sulphoaluminate. The results so far prove that steelmaking slags have the potential to be used as raw material, since sulphoaluminate along with polymorphs of dicalcium silicate and ferrite phases were detected after firing at 1200 degrees C in an air atmosphere.

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