| 8221. |
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| 8222. |
- Stenholm, Daniel, 1989, et al.
(författare)
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Knowledge Management Life Cycle: An Individual's Perspective
- 2014
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Ingår i: DS 77: Proceedings of the DESIGN 2014 13th International Design Conference. - 1847-9073. ; 2014-January, s. 1905-1914
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Konferensbidrag (refereegranskat)abstract
- Product development projects are expected to deliver results according to project goals. However, long-term success (over product generations) is diminishing when little time is given for knowledge capture and reuse. Effects of inefficient knowledge management (KM) become apparent when valuable knowledge is lost over time. Core barriers that decrease efficiency in KM, at the case companies, are mapped into a knowledge life cycle model, based on an individual’s perspective. To improve KM, instant knowledge work (acquisition, creation, refinement, sharing) is presented as a mind-set and a tool.
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| 8223. |
- Stenlund Nilsson Ivner, Jenny, 1976-
(författare)
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Municipal Energy Planning : Scope and Method Development
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Swedish municipalities are required to produce a municipal energy plan for their energy supply and use. Whether energy planning is suitable to manage local energy systems, however, is subject to debate. This thesis maps municipal energy planning: the scopes of energy plans and whether goals stated in energy plans are fulfilled. It also presents a pilot project with the implementation of an energy planning process where four different decision-making tools were applied: a Citizen’s panel, scenario techniques and quantitative and qualitative environmental assessments. The results from the mapping of energy planning and the experiences from the pilot project are then the bases for a discussion about the effectiveness of energy planning. The thesis is based on six papers; five scientific papers and one working paper. The first three papers contribute to mapping municipal energy planning in terms of expressed volition (goals, measures and strategies in the energy plans), whether goals are fulfilled and the extent of environmental analyses and assessments in the plans. The three subsequent papers present the implementation and evaluations of the energy planning process in the pilot project. The scopes of the studied energy plans have varied over time and have been adaptive to external factors such as contemporary energy policies and international trends. Environmental analyses and assessments were more commonly occurring in the energy plans adopted between 2006 and 2008 compared to those adopted between 1995 and 1998. The environmental analyses and assessments were however less comprehensive in the newer energy plans. Most positive development, in terms of fulfilled goals, took place for issues within the power of the local authority, for example district heating expansion and energy efficiency measures in public buildings. Experiences from the pilot project showed that decision-making tools can contribute to a broader scope of energy planning, more comprehensive environmental assessments and legitimacy. Based on the research findings possibilities for more effective energy planning are discussed. Effectiveness is discussed in terms of scope and legitimacy and how a broad scope and legitimacy are affected by the use of decision-making tools. It is concluded that energy planning has potential for being an effective tool for strategic energy work at the local level. The use of decision-making tools can also contribute to learning as well as legitimacy to energy planning.
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| 8224. |
- Stenlåås, Ola
(författare)
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On the Impact of Piston Motion and In-Cylinder Charge Composition on Energy Release, Auto Ignition and Emission Formation in Premixed Charge Internal Combustion Engines
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The results presented in this thesis can be divided into four areas of investigation: Investigation of the effect of new volume-crank angle relations on engine emissions, power and efficiency; investigation of nitrogen oxides effect on auto ignition and knock in SI engines; investigation of premixed SI and HCCI engine operation with the alternative fuels hydrogen and reformed methanol gas (RMG); software development of a detailed chemical kinetics zonal engine model. Model development of the in-house two-zone chemical kinetic code focused on expansion of the Jacobian matrix to allow simulations of variable in-cylinder charge. Addition of engine simulation sub-routines to achieve full cycle simulation capacity were made. The routines added handle flow through valves and both internal and external residual gas mixing. Also expansion of the solver and development of the code to achieve multi-zone capacity was made. Nitric oxide was, both in a modeling study and in an experimental study, found to have an impact on auto ignition. The modeling study showed a maximum auto ignition promoting effect at 500 ppm. The experimental study showed increased knock intensity when NO was added but no maximum promoting effect was noted. Premixed engine HCCI and SI operation fuelled with hydrogen and RMG was analyzed from operating range, power, efficiency and emission perspectives. For the SI cases empirical flame speed expressions based on the engine related parameters lambda, engine speed, minimum cylinder height and ignition angle were developed. In the efficiency discussions the reformation of methanol to hydrogen or RMG is taken into account. The range of operation was limited to lean combustion. Engine power when using the investigated fuels was found to be limited to about half of what is achievable in premixed operation on other fuels. Indicated efficiencies were found to be high and the emissions of NO from the HCCI operated engine were low but the low combustion efficiency at high lambdas resulted in high amounts of unburned fuel in the exhaust gas. Modeling of new relations of volume-crank angle dependence was made. The efficiency and the power of the engine modeled were not altered in any major way by changes in the volume-crank angle dependence as long as the expansion ratio was held constant. Engine emission of NO and CO could be altered by changes in the volume-crank angle dependence but the changes were not of the magnitude that the concept can replace the catalyst used to lower emissions from engines today.
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| 8225. |
- Stenlåås, Ola, et al.
(författare)
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Reformed Methanol Gas as Homogeneous Charge Compression Ignition Engine Fuel
- 2004
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Ingår i: SAE Special Publications. ; 2004:1896, s. 127-140
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Konferensbidrag (refereegranskat)abstract
- Hydrogen has been proposed as a possible fuel for automotive applications. Methanol is one of the most efficient ways to store and handle hydrogen. By catalytic reformation it is possible to convert methanol into hydrogen and carbon monoxide. This paper reports an experimental investigation of Reformed Methanol Gas as Homogeneous Charge Compression Ignition (HCCI) engine fuel. The aim of the experimental study is to investigate the possibility to run an HCCI engine on a mixture of hydrogen and carbon monoxide, to study the combustion phasing, the efficiency and the formation of emissions. Reformed Methanol Gas (RMG) was found to be a possible fuel for an HCCI engine. The heat release rate was lower than with pure hydrogen but still high compared to other fuels. The interval of possible start of combustion crank angles was found to be narrow but wider than for hydrogen. The high rate of heat release limited the operating range to lean (glmg3) cases as with hydrogen. On the other hand, operation on extremely lean mixtures (glme6) was possible. The operating range was investigated using intake air temperature for control and also this control interval was found to be narrow but more extensive than for pure hydrogen, especially when richer cases were run. The maximal load in HCCI mode was a net Indicated Mean Effective Pressure (IMEPn) of 3.5 bar for RMG. This is the same maximum IMEPn as for hydrogen. It is about half the load possible in Spark Ignition (SI) mode and about half the maximal load in HCCI mode with other fuels. For the loads where HCCI operation was possible, indicated thermal efficiency for HCCI was superior to that of SI operation. The indicated overall efficiency of the engine-reformer system is as high for SI as for HCCI operation when RMG is used as fuel. NOx emissions were, as expected, found to decrease when the equivalence ratio was lowered. High levels of carbon monoxide were found in the exhaust. Emissions of hydrocarbons were detected, probably originating from evaporated and partially oxidized lubrication oil.
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| 8226. |
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| 8227. |
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| 8228. |
- Stensson, Annika, et al.
(författare)
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Experimental investigation of some consequences of low velocity impacts in the chaotic dynamics of a mechanical system
- 1994
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Ingår i: Philosophical Transactions / Royal Society of London. Physical sciences and engineering (1990-1995). - 0962-8428. ; 347:1683, s. 439-448
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Tidskriftsartikel (refereegranskat)abstract
- An experimental investigation of an impacting system is presented. The dynamical behaviour of the experimental system is compared with that of a simple model system using the common notion of an instantaneous velocity change, with outgoing velocity being a function of incoming velocity. This type of model has singularities in the Poincare mappings used to describe the dynamics and this produces effects not found in smooth dynamical systems. The major contribution of this study is to show that these effects are also characteristic of the experimental system. One of those effects is that the chaotic attractors exhibit certain geometric features. The accuracy of the measurements made it possible to identify this effect in the experiment. As the experimental system is more complicated than the model, our measurements support that these features are present in more complex models. Thus it is demonstrated that the geometric features provide a diagnostic tool for impact studies
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| 8229. |
- Stensson, Annika, et al.
(författare)
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Industry demands on vehicle development - methods and tools
- 2000
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Ingår i: Vehicle System Dynamics. - : Taylor & Francis Ltd.. - 0042-3114 .- 1744-5159. ; 33:Suppl, s. 202-213
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Tidskriftsartikel (refereegranskat)abstract
- A very important goal of mechatronics in system development is the integration of mechanical, electronic and software subsystems in order to increase functionality, minimize weight, and reduce production costs. In this work, industry demands on methods and tools for mechatronic vehicle development are addressed from the current product development in industry. The development of a mechatronic car door concept and dynamic stability control are used as examples to identify strong and weak parts of the current processes. Railway vehicle development aspects are also discussed. It is shown that a very important aspect for a successful mechatronic design is co-operation in an interdisciplinary design team. In terms of design methodology, the systematic identification of mechatronic potential based on function analysis is a main issue. Computer tools and technology for concept simulation, co-simulation, managing of models with different complexity as well as model exchange are identified as important demands for future effective development of mechatronic vehicles.
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| 8230. |
- Stensson, Annika, et al.
(författare)
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Industry demands on vehicle development - methods and tools
- 1999
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 33:Suppl 1, s. 202-213
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Tidskriftsartikel (refereegranskat)abstract
- A very important goal of mechatronics in system development is the integration of mechanical, electronic and software subsystems in order to increase functionality, minimize weight, and reduce production costs. In this work, industry demands on methods and tools for mechatronic vehicle development are addressed from the current product development in industry. The development of a mechatronic car door concept and dynamic stability control are used as examples to identify strong and weak parts of the current processes. Railway vehicle development aspects are also discussed. It is shown that a very important aspect for a successful mechatronic design is co-operation in an interdisciplinary design team. In terms of design methodology, the systematic identification of mechatronic potential based on function analysis is a main issue. Computer tools and technology for concept simulation, co-simulation, managing of models with different complexity as well as model exchange are identified as important demands for future effective development of mechatronic vehicles.
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