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  • 101. Abeysekera, John D.A.
    et al.
    Shahnavaz, Houshang
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Chapman, Larry J.
    Ergonomics in developing countries1990In: Advances in industrial ergonomics and safety 2: proceedings of the annual International Industrial Ergonomics and Safety Conference held in Montreal, Quebec, Canada, 10-13 June 1990 / [ed] Biman Das, Taylor and Francis Group , 1990, p. 771-778Conference paper (Refereed)
  • 102.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Gao, Chuansi
    Luleå tekniska universitet.
    The identification of factors in the systematic evaluation of slip prevention on icy surfaces2001In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 28, no 5, p. 303-313Article in journal (Refereed)
    Abstract [en]

    Slips and falls on icy roads often result in fractures or sprains and is a major problem in Nordic countries. Walking trials by 25 subjects wearing four types of winter shoes on five different icy walking surfaces provided subjective and objective measures of tendency to slip and number of slips, respectively. Since friction is a major determinant of a slip, the influence of material spread on icy surfaces, the surface temperatures and the shoe soling characteristics versus the Coefficient of Friction (COF) of the shoes were measured. Sand and gravel on icy roads had positive effects on improving COF. The study revealed that the aetiology of slips and falls is multi-faceted and attempts to solve the problem must adopt a systems approach. Perception of risk, aging, training, experience and postural balance are other factors to be considered in preventing slips and falls. Future research should concentrate on the degree of impact of each factor to the aetiology of slips and falls, which can help to decide priority action in preventing slips and falls.

  • 103.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Holmér, Ingvar
    National Institute for Working Life.
    Termiska egenskaper hos skyddshjälmar: förbättring, validering och standardisering av en mätmetod1997Report (Other academic)
  • 104.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Holmér, Ingvar
    National Institute for Working Life.
    Utveckling av metoder för provning och värdering av personlig skyddsutrustning med avseende på våt värmeavgivning1996Report (Other academic)
  • 105.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Holmér, Ingvar
    National Institute for Working Life.
    Liu, Xiaoxiong
    Gao, Chaunsi
    Wu, Zenhua
    Some design recommendations to improve comfort in helmets: a case study from China1996In: Journal of Human Ergology, ISSN 0300-8134, Vol. 25, no 2, p. 145-154Article in journal (Refereed)
    Abstract [en]

    Unless the basic user needs are satisfied in safety helmets, it is difficult to get workers to wear them habitually and for long periods. Hotness, weight and fitting problems are major wearability issues that require improvements. The enormous need for an optimally designed helmet in China prompted a case study on comfort aspects in helmets. The subjective impressions of the wearers of test helmets provided useful information for design changes to improve comfort. The heat transfer measurements through helmets indicated the need for ventilation openings to be provided on the shell of plastic helmets. Due to the advantage of low weight and good ventilation, it is recommended that cane helmets be further developed to improve protection, wearability and durability, and subsequently be produced in large scale

  • 106.
    Abeysekera, John
    et al.
    ndustrial Ergonomics, Work Science Academy (WSA), Linköping.
    Illankoon, Prasanna
    Work Science Academy (WSA), Kandana, Sri Lanka.
    The demands and benefits of ergonomics in Sri Lankan apparel industry2016In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 55, no 2, p. 255-261Article in journal (Refereed)
    Abstract [en]

    Apparel exports bring in sizeable foreign income to Sri Lanka. To protect and promote this industry is a paramount need. This can be carried out by applying Human Factors/Ergonomics (HFE) which has proved to control negative effects at work places. This paper reports a case study which describes the demands and benefits of HFE in MAS Holdings which owns a large share of the apparel industry in Sri Lanka.The study consisted of walk through observation survey, a questionnaire survey and ergonomic work place analysis followed by a training programme to selected employees in three companies.Positive responses to questionnaires revealed good ergonomic practices in the work places surveyed. Ergonomically unfit chairs and potential hazards e.g. exposure to noise and hot environment were detected. It is seen that MAS have introduced strategies originated by Toyota Production System viz. 5S, Kaizen, six sigma etc., which are in fact ergonomic methods. A progressive project MAS boast of viz. ‘MAS Operating System’ (MOS) empowers training and development to employees.MAS Holdings has adequately realized the benefits of applying HFE as evident by the number of awards received. Relevant companies were advised to take appropriate corrective measures to control the potential hazards.

  • 107.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Liu, Xiaoxiong
    Holmér, Ingvar
    National Institute for Working Life.
    A method to measure the total heat transfer through helmets: prerequisite to design thermally comfortable helmets1992In: Proceedings / Fourth Scandinavian Symposium on Protective Clothing against Chemicals and other Health Hazards (NOKOBETEF IV), Kittilä, Finland, 5-7 February [1992] / [ed] Helena Mäkinen, Vantaa: Institute of Occupational Health , 1992, p. 42-47Conference paper (Refereed)
  • 108.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Liu, Xiaoxiong
    Luleå tekniska universitet.
    Piamonte, D. Paul
    Luleå tekniska universitet.
    Body sizes and other human factors differences between Swedish and foreign students in Swedish universities1994In: Ergonomics for Quality Life: Proceedings of the Third Pan-Pacific Conference on Occupational Ergonomics, Seoul, Korea, 13-17 November 1994, PPCOE , 1994, p. 420-423Conference paper (Refereed)
    Abstract [en]

    Past studies have shown large differences in body size between people of Industrialized Countries (ICs) and Industrially Developing Countries (IDCs). These differences can have negative effects on the usage of technology which IDCs today acquire to a great extent from ICs. At the same time, the number of students from IDCs seeking education and training in universities in ICs is increasing. This paper reports on the impact of human factors differences particularly body size differences between foreign and local students on the use of university facilities, based on anthropometric and questionnaire surveys carried out on a small scale by foreign graduate students of Lulea University, Sweden. The study revealed large differences in body sizes between local and foreign students. The questionnaire survey of foreign students showed that there are other significant human factors differences such as the use of a foreign language, viz. Swedish which is unique to Scandinavia, and the exposure to long cold winters. Whether these differences in human factors influence the acquisition of knowledge or learning capacity of foreign students is worth further investigation.

  • 109.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Lönnroth, Emma-Christin
    Piamonte, Dominic Paul T
    Luleå tekniska universitet.
    Shahnavaz, Houshang
    Welcoming the millennium from a decade of growth and development in ergonomics education and promotion2001In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 27, no 6, p. 365-Article in journal (Other academic)
  • 110.
    Abeysekera, John
    et al.
    Luleå tekniska universitet.
    Shahnavaz, Houshang
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Adaptation to discomfort in personal protective devices: an example with safety helmets1990In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 33, no 2, p. 137-145Article in journal (Refereed)
    Abstract [en]

    Discomfort in the use of personal protective devices (PPD) has been one of the chief causes of their non-use. A field trial using industrial helmets was carried out to ascertain whether by training and repeated wearing subjects could experience a significant adaptation to discomfort. Ten subjects took part in the trial in a tropical environment by wearing helmets repeatedly (6 h a day) for one month. Subjective evaluations of discomfort were made at the end of the 1st, 3rd, 5th, 14th and 30th day. It was revealed that complaints of discomfort, viz. hotness, heaviness, bad fit, etc., decreased markedly throughout the 30 day period. Though positive responses of adaptation to discomfort seem to reach an optimum towards 30 days, it is difficult to draw any conclusions on the optimum period of adaptation for each discomfort factor. In relation to inherent discomforts that are extremely difficult to overcome without compromising the protection efficiency of a PPD, the principle of adaptation seems to be a very important facet which has to be developed for an effective PPD programme.

  • 111. Abhale, P.B.
    et al.
    Guha, M
    Nurni, Viswanathan
    Ballal, N.B.
    Prediction of gas flow through layered burden prolies in blast furnace2006Conference paper (Refereed)
  • 112. Abhale, P.B.
    et al.
    Guha, M.
    Ramna, M.V.
    Nurni, Viswanathan
    Ballal, N.B.
    Prediction of cohesive zone in a blast furnace using wall pressure tap data: modelling appproach2008Conference paper (Refereed)
  • 113. Abhale, P.B.
    et al.
    Guna, M.
    Ramna, R.V.
    Nurni, Viswanathan
    Investigation of computational aspects in simulation of gas flow in blast furnace2009Conference paper (Refereed)
  • 114. Abhale, P.B.
    et al.
    Nurni, Viswanathan
    Ballal, N.B.
    Blast furnace modelling2005Conference paper (Refereed)
  • 115.
    Abhale, P.B.
    et al.
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay.
    Nurni, Viswanathan
    Ballal, N.B.
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay.
    Efficient simulation of gas flow in blast furnace2009In: Computers, Materials & Continua, ISSN 1546-2218, Vol. 10, no 2, p. 195-216Article in journal (Refereed)
    Abstract [en]

    Simulation of gas flow in a multilayered non-isothermal packed bed is useful for blast furnace operators in deciding appropriate charging strategy. While using an anisotropic form of Ergun equation to simulate gas flow through such systems, a new solution methodology for non-isothermal gas with varying density flowing through a layered burden has been proposed. This involves handling non-linearity due to gas density variation with pressure and temperature by solving for the square of pressure instead of pressure directly and handling the non-linearity due to vertical bar nu vertical bar term in the Ergun equation by solving linearized form of Ergun equation and updating vertical bar nu vertical bar iteratively. The proposed scheme is capable of predicting the effect of layer structure on gas flow with economy in number of grid points as well as computation time

  • 116. Abhale, P.B.
    et al.
    Nurni, Viswanathan
    Ballal, N.B.
    Efficient simulation of gas flow in blast furnace2008Conference paper (Refereed)
  • 117. Abhale, P.B.
    et al.
    Yadav, V.K.
    Nurni, Viswanathan
    Ballal, N.B.
    Investigation of mal-distribution in blast furnace aerodynamics using a three dimensional simulation model2010Conference paper (Refereed)
  • 118.
    Abhale, Prakash Bansi
    et al.
    Global R and D, ArcelorMittal, Kolkatta.
    Yadav, Vishal Kumar
    Department of Metallurgy and Materials Engineering (MTM), Katholieke Universiteit, Leuven.
    Nurni, Viswanathan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Ballal, Bharath Nidambur
    Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay.
    Efficient computation of gas flow in blast furnace in 3-D2012In: 6th Int. Congress on the Science and Technology of Ironmaking 2012, ICSTI 2012: Including Proceedings from the 42nd Ironmaking and Raw Materials Seminar, and the 13th Brazilian Symp. on Iron Ore, 2012, Vol. 1, p. 722-732Conference paper (Refereed)
    Abstract [en]

    Blast furnace continues to occupy prominent place among iron making technologies as it accounts for more than 90% of the hot metal produced in the world. In India, as a part of initiative from Ministry of Steel, efforts are being made to develop offline as well as online models with an aim to improve blast furnace performance. As a part of this effort, offline comprehensive models simulating the internal state of an operating blast furnace are being developed. Such comprehensive models involve systematic integration of various sub-models for gas flow, solid flow, reaction kinetics, enthalpy balance etc. Unlike in many other systems, these sub-processes are highly interlinked in blast furnace and hence call for large number of iteration among the sub-models which ultimately results in significant computation time. Our efforts in integration of these sub-models have indicated that the gas flow is one of the important bottle necks in achieving faster computation. This has led to a development of new and efficient computation scheme to simulate the gas flow in 2-D [1]. This new scheme provided efficient way of handling complex burden profile in a blast furnace. This paper presents the extension of this 2-D gas flow model to 3-D. Further, the 3-D model has been used to investigate the asymmetry in gas flow which can arise from blanking the tuyeres, asymmetric fusion or cohesive zone or formation scabs or scaffolds in the furnace behavior

  • 119.
    Abid, Fahim
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Busatto, Tatiano
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Intermodulation due to interaction of photovoltaic inverter and electric vehicle at supraharmonic range2016In: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway. NJ, 2016, p. 685-690, article id 7783471Conference paper (Refereed)
    Abstract [en]

    Advent of power electronic switching is introducing more and more non-linear loads in the low voltage grid. Besides harmonic current generation in the frequency range below 2 kHz, these non-linear loads are also responsible for current emission in the range of 2 kHz to 150 kHz, commonly known as supraharmonic emission. Supraharmonic currents mainly flow between nearby appliances and heavily influence the overall emission of neighboring devices. This paper presents an analysis of supraharmonic interaction between a photovoltaic inverter and an electric vehicle. It has been noticed that intermodulation distortion arises as a result of interaction between different switching frequencies used by the devices. Later, additional household equipment were added to photovoltaic and electric vehicle to observe their effect on intermodulation distortion. All the measurements were conducted in a controlled laboratory environment imitating a domestic customer.

  • 120.
    Abiri, Olufunminiyi
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Non-local models in manufacturing simulations2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ductile fracture presents challenges with respect to material modelling andnumerical simulations of localization. The strain and damage localization maybe unwanted as it indicates a failure in the process or, as in the case ofmachining and cutting, a wanted phenomenon to be controlled. The latterrequires a higher accuracy regarding the modelling of the underlying coupledplastic and fracturing/damage behaviour of the material, metal in the currentcontext as well as the stability and robustness of the simulation procedure.This aim of this work is to develop, evaluate and implement formulations thatcan efficiently and reliably handle localization problems in machiningsimulations. The focus is on non-local models. The non-local models extendthe standard continuum mechanics theory by using non-local continuumtheory in order to achieve mesh independent results when simulating fractureor shear localization.The non-local damage model is implemented and various formulations areevaluated in a Matlab™ based finite element code. The chosen algorithm wasthen implemented in commercial software. The implementations remedy themesh sensitivity problem and gives convergent solution for metal cuttingsimulations with reasonable cost. The length scale associated with the nonlocalmodels are in the current context considered as a numericalregularization parameter. The model has been applied in machiningsimulations and compared with measurements from industry.Keywords: Finite element simulation; Non-local damage; Plasticity; Machining

  • 121.
    Abiri, Olufunminiyi
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Simplifications of non-local damage models2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ductile fracture presents challenges with respect to material modelling and numerical simulations of localization. The strain and damage localization may be unwanted as it indicates a failure in the process or, as in the case of machining and cutting, a wanted phenomenon to be controlled. The latter requires a higher accuracy regarding the modelling of the underlying coupled plastic and fracturing/damage behaviour of the material, metal in the current context as well as the robustness of the simulation procedure. The focus of this thesis is on efficient and reliable finite element solution of the localization problem through the non-local damage model. The non-local damage model extends the standard continuum mechanics theory by using non-local continuum theory in order to achieve mesh independent results when simulating fracture or shear localization. In this work, the non-local damage model and its various simplifications are evaluated in an in-house finite element code developed using Matlab™. The accuracy, robustness, efficiency and costs of the models are investigated and also compared to a general multi-length scale finite element formulation. A numerical study versus published data is used to demonstrate the validity of the model. The explicit non-local damage variant will be implemented in a commercial finite element code for use in machining simulation

  • 122.
    Abiri, Olufunminiyi
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Non-local damage models in manufacturing simulations2013Conference paper (Refereed)
    Abstract [en]

    Localisation of deformation is a problem in several manufacturing processes. Machining is an exception where it is a wanted feature. However, it is always a problem in finite element modelling of these processes due to mesh sensitivity of the computed results. The remedy is to incorporate a length scale into the numerical formulations in order to achieve convergent solutions. Different simplifications in the implementation of a non-local damage model are evaluated with respect to temporal and spatial discretisation to show the effect of different approximations on accuracy and convergence.

  • 123.
    Abiri, Olufunminiyi
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Non-local damage models in manufacturing simulations2015In: European journal of mechanics. A, Solids, ISSN 0997-7538, E-ISSN 1873-7285, Vol. 49, p. 548-560Article in journal (Refereed)
    Abstract [en]

    Localisation of deformation is a problem in several manufacturing processes. Machining is an exception where it is a wanted feature. However, it is always a problem in finite element modelling of these processes due to mesh sensitivity of the computed results. The remedy is to incorporate a length scale into the numerical formulations in order to achieve convergent solutions. Different simplifications in the implementation of a non-local damage model are evaluated with respect to temporal and spatial discretisation to show the effect of different approximations on accuracy and convergence.

  • 124.
    Abiri, Olufunminiyi
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Qin, Hao
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Comparison of Multiresolution Continuum Theory and Nonlocal Dame model for use in Simulation of Manufacutring Processes2016In: International Journal for Multiscale Computational Engineering, ISSN 1543-1649, Vol. 14, no 1, p. 81-94Article in journal (Refereed)
    Abstract [en]

    Modelling and simulation of manufacturing processes may require the capability to account for localization behavior, often associated with damage/fracture. It may be unwanted localization indicating a failure in the process or, as in the case of machining and cutting, a wanted phenomenon to be controlled. The latter requires a higher accuracy regarding the modelling of the underlying physics, as well as the robustness of the simulation procedure. Two different approaches for achieving mesh-independent solutions are compared in this paper. They are the multiresolution continuum theory (MRCT) and nonlocal damage model. The MRCT theory is a general multilength-scale finite element formulation, while the nonlocal damage model is a specialized method using a weighted averaging of softening internal variables over a spatial neighborhood of the material point. Both approaches result in a converged finite element solution of the localization problem upon mesh refinement. This study compares the accuracy and robustness of their numerical schemes in implicit finite element codes for the plane strain shear deformation test case. Final remarks concerning ease of implementation of the methods in commercial finite element packages are also given.

  • 125.
    Abiri, Olufunminiyi
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials. University of Johannesburg, South Africa.
    Svoboda, Ales
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Wedberg, Dan
    Controlling Thermal Softening Using Non-Local Temperature Field in Modelling2016In: Journal of Machining and Forming Technologies, ISSN 1947-4369, Vol. 8, no 1-2, p. 13-28Article in journal (Refereed)
    Abstract [en]

    One of the aims of this work is to show that thermal softening due to the reduced flow strength of a material with increasing temperature may cause chip serrations to form during machining. The other purpose, the main focus of the paper, is to demonstrate that a non-local temperature field can be used to control these serrations. The non-local temperature is a weighted average of the temperature field in the region surrounding an integration point. Its size is determined by a length scale. This length scale may be based on the physics of the process but is taken here as a regularization parameter.

  • 126.
    Abiri, Olufunminiyi
    et al.
    Institute of Intelligent Systems, University of Johannesburg.
    Wedberg, Dan
    AB Sandvik Coromant.
    Svoboda, Ales
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Non-Local Modelling of Strain Softening in Machining Simulations2017In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 225, article id 012053Article in journal (Refereed)
    Abstract [en]

    Non-local damage model for strain softening in a machining simulation is presented in this paper. The coupled damage-plasticity model consists of a physically based dislocation density model and a damage model driven by plastic straining in combination with the stress state. The predicted chip serration is highly consistent with the measurement results. 

  • 127. Abitew, Aymiro
    et al.
    Zeinali, Amin
    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.
    Hydraulic conductivity of tailings deposit used as dam construction material at Aitik mine in Sweden2013Conference paper (Refereed)
    Abstract [en]

    Distribution of vertical and horizontal hydraulic conductivity and their correlation to geotechnical parameters affecting the hydraulic conductivity of tailings deposit at Aitik mine have been determined. The investigation was carried out along three sections which cover approximately 3km2 of area and 4-5meters of thickness. 3-5 test pits have been excavated in each section and samples are collected from various levels. The horizontal hydraulic conductivity has been found to have a good relation with fraction of fine particles in the deposit and void ratio. However, similar to the results of Jantzer et al (2008) from the same mine, the vertical hydraulic conductivity did not correspond to void ratio. According to evaluation of existing empirical relations to estimate hydraulic conductivity from particle size analysis, Hazen formula (1911) gives 25 and 45 times the measured values of vertical and horizontal hydraulic conductivity respectively. On the other hand, Chapuis et al (2003) has not been succeeded for prediction of hydraulic conductivity of undisturbed samples from the investigated area. However, it gives comparatively good prediction of hydraulic conductivity for disturbed samples which are compacted to their field dry density.

  • 128. Abitew, Aymiro
    et al.
    Zeinali, Amin
    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.
    Hydraulic conductivity of tailings sand used for dam construction at Aitik mine in Sweden2012In: SWEMP 2012: International symposium on Environmental Issues and Waste Management in Energy and Mineral Production, 2012Conference paper (Refereed)
    Abstract [en]

    Distribution of vertical and horizontal hydraulic conductivity and their correlation to geotechnical parameters affecting the hydraulic conductivity of tailings deposit at Aitik mine have been determined. The investigation was carried out along three sections which cover approximately 3km2 of area and 4-5meters of thickness. 3-5 test pits have been excavated in each section and samples are collected from various levels. The horizontal hydraulic conductivity has been found to have a good relation with fraction of fine particles in the deposit and void ratio. However, similar to the results of Jantzer et al (2008) from the same mine, the vertical hydraulic conductivity did not correspond to void ratio. According to evaluation of existing empirical relations to estimate hydraulic conductivity from particle size analysis, Hazen formula (1911) gives 25 and 45 times the measured values of vertical and horizontal hydraulic conductivity respectively. On the other hand, Chapuis et al (2003) has not been succeeded for prediction of hydraulic conductivity of undisturbed samples from the investigated area. However, it gives comparatively good prediction of hydraulic conductivity for disturbed samples which are compacted to their field dry density.

  • 129.
    Abolmasoumi, Amirhossein
    et al.
    Department of Electrical Engineering, Faculty of Engineering, Arak University.
    Sayyaddelshad, Saleh
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Observer design for a class of nonlinear delayed systems with unknown inputs and Markovian jump parameters2012In: ICCAS 2012: 12th International Conference on Control, Automation and Systems, 2012, p. 1848-1852Conference paper (Refereed)
    Abstract [en]

    The problem of full-order observer design for a class of delayed nonlinear systems with unknown inputs and Markovian jumping parameters is considered. The design method is formulated as solving a set of linear matrix inequalities (LMI's). Extending the results of nonlinear observer design to Markovian jump systems with time-varying delays is the main advantages of this paper. The sufficient LMI conditions are dependent on both the upper and lower bounds of delay. The effectiveness of the proposed method is shown via an illustrative example.

  • 130.
    Abrahamsson, Kenneth
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Activity: European conference on promoting workplace health2006Conference paper (Other (popular science, discussion, etc.))
  • 131.
    Abrahamsson, Kenneth
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Activity: International Conference on Vocational Education and Training Reform: comments on current policies and development2005Conference paper (Other (popular science, discussion, etc.))
  • 132. Abrahamsson, Kenneth
    Adult education in Sweden and the United States: Working Life in Sweden No. 381990Report (Other (popular science, discussion, etc.))
    Abstract [en]

    All young persons in Sweden have to complete 9 years of basic compulsory schooling. More than 95 percent opt for an additional 2 or 3 years of upper secondary school, after which they have free access to further education. The system of adult education is designed to bridge the gaps between generations and to provide opportunities for recurrent, lifelong education. The traditionally strong position of adult education is partly tied to the large number of providers. Formal adult education comprises basic education operated by authorities through government grants and municipal adult education. Popular adult educational activities are studies at folk high schools or under the aegis of adult educational associations. Labor market training takes the form of specially organized vocational training or uses the regular educational system. Personnel education and inservice training are educational activities aimed at employees and organized on the employers' terms and at their expense in companies and national or local authorities. The government has tried to establish the necessary preconditions for adult educational activities, including adult education in all municipalities, educational financing, educational leave, studies as part of the renewal of working life, and adult education as an expression of general welfare policy

  • 133. Abrahamsson, Kenneth
    Adult literacy and basic skills in Sweden: an overview of policy issues and research needs1990Report (Other (popular science, discussion, etc.))
  • 134. Abrahamsson, Kenneth
    Adult participation in Swedish higher education: a study of organizational structure, educational design and current policies1986Book (Other academic)
  • 135.
    Abrahamsson, Kenneth
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Aktivitet: EDEN 2005 Annual Conference: reflections on overeducation, underlearning and anorectic work organisations2005Conference paper (Other (popular science, discussion, etc.))
  • 136.
    Abrahamsson, Kenneth
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Arbetslivsforskningen och parterna har vänt varandra ryggen2006In: TCO-tidningen, ISSN 0346-2935, no 5, p. 10-Article in journal (Other (popular science, discussion, etc.))
  • 137. Abrahamsson, Kenneth
    Arbetstiden som forskningsfält1998In: Arbetstiden, jobben & framtiden, Stockholm: Arbetsmiljöfonden , 1998, p. 15-21Chapter in book (Other (popular science, discussion, etc.))
  • 138. Abrahamsson, Kenneth
    Arbetstider i olag1998In: Arbetstiden, jobben & framtiden, Stockholm: Arbetsmiljöfonden , 1998, p. 7-14Chapter in book (Other (popular science, discussion, etc.))
  • 139.
    Abrahamsson, Kenneth
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human Work Science.
    Banbrytare, livsberättelser och lärande: en efterskrift2007In: Det krokiga lärandet, Stockholm: NTG-lärprojektet : Paraplyprojektet , 2007, p. 150-175Chapter in book (Other (popular science, discussion, etc.))
  • 140. Abrahamsson, Kenneth
    Bildningssyn och utbildningsreformer: om behovet av bildningsmål i gymnasium och högskola1984Collection (editor) (Other academic)
  • 141. Abrahamsson, Kenneth
    Bridging the gap between education and work1999In: Vocational and adult education in Europe, Dordrecht ; London: Encyclopedia of Global Archaeology/Springer Verlag, 1999, p. 317-342Chapter in book (Other academic)
  • 142. Abrahamsson, Kenneth
    Concepts, organisation and current trends of lifelong education in Sweden1993In: International Journal of University Adult Education, ISSN 0074-3992, Vol. 32, no 3, p. 47-69Article in journal (Refereed)
  • 143. Abrahamsson, Kenneth
    Concepts, organization and current trends of lifelong education in Sweden1996In: Boundaries of adult learning, London: Taylor and Francis Group , 1996, p. 169-182Chapter in book (Other academic)
    Abstract [en]

    Swedish adult education can be divided into three major periods. The concept of self-education symbolizes the first period. Study circles and folk high schools provided alternative learning options for adults. The second period can be characterized by a diversified system of publicly organized adult education. Special attention was given to broadening the options for adults with short prior educaiton to study during working hours. In the third period policy decisions were taken to open up for a more flexible organization of adult education. Parliament decided to create so-called renewal funds and 6 billion kronor were used for corporate learning strategies during five years starting from 1986. The next decade will be a crossroads for swedish adult education. To-day the main proposal is to change the legal status of the employment training board from a public agency to a free enterprise in the competence market.

  • 144. Abrahamsson, Kenneth
    Cooperative education, experiential learning and personal knowledge: a selection of papers on experiential learning presented at the Vth international conference on higher education, University of Lancaster, England, September 1-4, 19811982Collection (editor) (Other academic)
  • 145. Abrahamsson, Kenneth
    Corporate classrooms: some Swedish experiences1988In: International Journal of University Adult Education, ISSN 0074-3992, Vol. 27, no 2, p. 35-45Article in journal (Refereed)
  • 146. Abrahamsson, Kenneth
    Corporate classrooms: some Swedish experiences1987Report (Other (popular science, discussion, etc.))
  • 147. Abrahamsson, Kenneth
    Das Berufsbildungssystem in Schweden2000Report (Other academic)
  • 148. Abrahamsson, Kenneth
    Den frusna samhällsdialogen: om medierna, myndigheterna och medborgarna1983Book (Other academic)
  • 149. Abrahamsson, Kenneth
    Den lilla samhällsdialogen som mångvetenskapligt forskningsområde1995In: Den lilla samhällsdialogen, Stockholm: College of Liberal Arts and Sciences, 1995, p. 115-128Chapter in book (Other academic)
  • 150. Abrahamsson, Kenneth
    Den "nya" utbildningsklyftan en utmaning för skola och vuxenutbildning: Vux 901986In: Skolledaren, ISSN 0037-6515, no 10, p. 6-9Article in journal (Other (popular science, discussion, etc.))
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