| 24601. |
- Lindgren, Lars, 1979, et al.
(författare)
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Drive-Cycle Simulations of Battery-Electric Large Haul Trucks for Open-Pit Mining with Electric Roads
- 2022
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 15:13
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Tidskriftsartikel (refereegranskat)abstract
- Transport of ore and overburden in open-pit mines is often performed with large haul trucks. Battery-electric operation of haul trucks can significantly reduce the CO2 emissions and the fossil fuel dependence of open-pit mining. This simulation study investigates the feasibility and economy of operating large haul trucks battery-electrically, charging from an electric road system in the form of overhead trolley lines. The used simulation model is verified against measurements on diesel-electric haul trucks in normal operation. The simulation model is then tested with five drive cycles representing typical operations in the Aitik copper mine in northern Sweden. This simulation study shows that battery-electric operation with an electric road is feasible. It is shown that battery-electric operation is much cheaper than diesel-electric operation under reasonable assumptions. It is also much cheaper than diesel-electric operation assisted by an electric road.
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| 24602. |
- Lindgren, Mikaela, 1987, et al.
(författare)
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Toward a Comprehensive Mechanistic Understanding of Hydrogen Uptake in Zirconium Alloys by Combining Atom Probe Analysis With Electronic Structure Calculations
- 2015
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Ingår i: ASTM Special Technical Publication. - 0066-0558. - 9780803175297 ; STP 1543, s. 515-539
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Konferensbidrag (refereegranskat)abstract
- The ability of a zirconium alloy to resist corrosion relies on a compromise between two opposing strategies. Minimizing the hydrogen pickup fraction (HPUF) by invoking metallic electron conduction in the barrier oxide results in rapid parabolic oxide growth. On the other hand, slow sub-parabolic barrieroxide growth, as reflected in rate limiting electron transport, may result in a high HPUF. The objective of the present study is to offer mechanistic insights as to how low concentrations of different alloying elements become decisive for the overall corrosion behavior. Combining atomistic microanalysis with first principles modeling by means of density functional theory, the speciation and redox properties of Fe and Ni towards hydrogen evolution are firstly explored.Complementary atom probe microanalysis at the metal–oxide interface provides evidence for Fe and Ni segregation to grain boundaries in Zircaloy-2 that propagates into the ZrO2 scale. Descriptors for how alloying elements in ZrO2 control electron transport as well as catalytic electron-proton recombination ingrain boundaries to form H2 are determined by means of theory. The findings are generalized by further atomistic modeling, and are thus put in the context of early reports from autoclave experiments on HPUFs of zirconium with the alloying elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Nb. A shunting mechanism which combines inner and outer hydrogen evolution mechanisms is proposed. Properties of the transient zirconium sub-oxide are discussed. A plausible atomistic overall understanding emerges.
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| 24603. |
- Lindgren, Natalia, et al.
(författare)
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Development of personalizable female and male pedestrian SAFER human body models
- 2024
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-9588 .- 1538-957X. ; 25:2, s. 182-193
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesVulnerable road users are globally overrepresented as victims of road traffic injuries. Developing biofidelic male and female pedestrian human body models (HBMs) that represent diverse anthropometries is essential to enhance road safety and propose intervention strategies.MethodsIn this study, 50th percentile male and female pedestrians of the SAFER HBM were developed via a newly developed image registration-based mesh morphing framework. The performance of the HBMs was evaluated by means of a set of cadaver experiments, involving subjects struck laterally by a generic sedan buck.ResultsIn simulated whole-body pedestrian collisions, the personalized HBMs effectively replicate trajectories of the head and lower body regions, as well as head kinematics, in lateral impacts. The results also demonstrate the personalization framework's capacity to generate personalized HBMs with reliable mesh quality, ensuring robust simulations.ConclusionsThe presented pedestrian HBMs and personalization framework provide robust means to reconstruct and evaluate head impacts in pedestrian-to-vehicle collisions thoroughly and accurately.
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| 24604. |
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| 24605. |
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| 24606. |
- Lindhe, Jonas, et al.
(författare)
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Challenges and potentials of using a local heat pump in a 5 GDHC solution: Results from field and laboratory evaluations
- 2024
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 289
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Tidskriftsartikel (refereegranskat)abstract
- In fifth generation district heating and cooling (5GDHC), the temperature range of the heat source is wider then in current common heat pump systems. The results of this study show that the heat pumps and chillers that are available in the market are not well adapted to 5GDHC applications due to the wide working range of 5GHDC. In order to maintain a high efficiency, current design parameters should be adjusted. This affects the dimensioning of all components in the refrigerant circuit and the required volume of refrigerant. An operational challenge specific to 5GDHC occurs when there is a low power demand at a relatively low temperature (eg. 35 °C) on the condenser side that coincides with a relatively high temperature (eg. 25 °C) on the evaporator side, resulting in a high thermal power during times with limited demand. Since the 5GDHC distributes both cooling and heating, it is also a challenge to successfully control the local heat pump in order that it fulfils the demands on both the hot and cold side. The heat pumps connected to 5GDHC systems have the potential to reach a high coefficient of performance (COP), due to the high temperature of the heat source. The challenge is to maintain a high COP throughout operation. At the ends of the heat pumps operational temperature range, the efficiency tends to drop considerably, resulting in a low System Efficiency Index compared to operations well within the operational range. This research seeks to address these challenges by highlighting better design principles in order to realize the untapped potential of 5GDHC systems. This is performed by investigating the influence of individual components on the performance of a local heat pump installed in a 5GDHC grid, assessed through theoretical simulations, field tests and laboratory measurements.
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| 24607. |
- Lindholm, Annika
(författare)
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Pulsating Combustion - Combustion Characteristics and Reduction of Emissions
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the search for high efficiency combustion systems pulsating combustion has been identified as one of the technologies that potentially can meet the objectives of clean combustion and good fuel economy.Pulsating combustion offers low emissions of pollutants, high heat transfer and efficient combustion. Although it is an old technology, the interest in pulsating combustion has been renewed in recent years, due to its unique features. Various applications of pulsating combustion can be found, mainly as drying and heating devices, of which the latter also have had commercial success. It is, however, in the design process of a pulse combustor, difficult to predict the operating frequency, the heat release etc., due to the lack of a well founded theory of the phenomenon. Research concerning control over the combustion process is essential for developing high efficiency pulse combustors with low emissions. Natural gas fired Helmholtz type pulse combustors have been the experimental objects of this study. In order to investigate the interaction between the fluid dynamics and the chemistry in pulse combustors, laser based measuring techniques as well as other conventional measuring techniques have been used. The experimental results shows the possibilities to control the combustion characteristics of pulsating combustion. It is shown that the time scales in the large vortices created at the inlet to the combustion chamber are very important for the operation of the pulse combustor. By increasing/decreasing the time scale for the large scale mixing the timing of the heat release is changed and the operating characteristics of the pulse combustor changes. Three different means for NOx reduction in Helmholtz type pulse combustors have been investigated. These include exhaust gas recirculation, alteration of air/fuel ratio and changed inlet geometry in the combustion chamber. All used methods achieved less than 10 ppm NOx emitted (referred to stoichiometric conditions). Results from a 3D-LES simulation model for chemically reacting flows have been validated using the experimental data obtained within this study. The simulations have been carried out at the Division of Combustion Physics. The 3D simulation model can be used as a tool for studying the complex phenomena encountered in pulsating combustion. Together with measurements of temperature fields and measurements of the concentration of different species (for example O2, NO and CH4) in the combustion chamber, even further enhanced understanding of the fundamental processes in pulse combustors can be achieved.
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| 24608. |
- Lindhult, Erik, et al.
(författare)
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Innovation capabilities and challenges for energy smart development in medium sized European cities
- 2016
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; :88, s. 205-211
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Tidskriftsartikel (refereegranskat)abstract
- Transition towards becoming Energy smart city integrating different areas of energy production, distribution and use in a community requires a spectrum of capabilities. The paper reports on findings from the EU planning project PLEEC, involving six medium sized European cities. The purpose of the paper is to describe innovation capabilities and challenges in the complex, systemic innovation journey of cities in the transition to sustainability. A case of implementing an innovative project for electrical vehicles in Eskilstuna is presented illustrating both technological potentials and innovation challenges.
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| 24609. |
- Lindman, M., et al.
(författare)
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Pedestrians interacting with a passenger car; A study of real world accidents
- 2011
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Ingår i: 2011 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; , s. 255-264
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Konferensbidrag (refereegranskat)abstract
- Pedestrian safety priorities for passenger cars are usually based on data with varying car makes and models. This study presents a new database, V-PAD (Volvo Cars Pedestrian Accident Database), with a homogeneous car sample providing a relevant, up-to-date distribution of accident situations as well as pedestrian characteristics and driver information. A total of 330 pedestrian car accidents are analyzed with the aim to present a first summary of the V-PAD data in terms of accident, injury and impact aspects. The database with cars of the same types gives unique possibilities to design and evaluate effective safety measures for pedestrian safety. The results in this study will form the basis for further improvements, both considering driver support and crash compatibility.
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| 24610. |
- Lindmark, Hampus, 1992
(författare)
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High-Temperature Corrosion in Waste-Fired Boilers: Insights into material selection for fluidized bed heat exchangers and the corrosivity of PbCl2
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The replacement of fossil fuels with waste-derived fuels for heat and electricity production has gained significant momentum in the European Union (EU), especially in the wake of the implementation of stricter waste management directives and the pursuit of ambitious climate goals. Combustion of waste, however, leads to the formation of a complex and highly corrosive flue gas that cause severe corrosion on important boiler equipment. Consequently, corrosion has significant impact on the operational cost and electrical efficiency of the power plant. As an approach to improve boiler efficiency, modern designed circulating fluidized bed (CFB) waste-fired boilers conduct the final heating of the superheated steam within the loop seal region. However, there is limited published research on the performance of different alloy types in this region of the boiler, and the influence of corrosive and erosive events on the material degradation mechanisms remains relatively elusive. Furthermore, in the water wall region of waste-fired boilers, elevated concentrations of Pb-containing compounds such as PbCl2 have been identified and linked to the accelerated corrosion rate of the tube material. Nevertheless, there is a limited comprehension of the underlying corrosion mechanism in PbCl2-induced corrosion of low-alloyed steel, which is often used as tube material in this area of the boiler. The aim of this thesis is to address these aforementioned concerns through a combination of field exposures and laboratory studies. A field exposure study was conducted on a commercial CFB boiler to assess the performance of relevant alloy types for superheater application in the loop seal region of the boiler and to improve the understanding of the synergetic effect of corrosion and erosion attacks on the material degradation mechanism. The results from the study revealed that novel FeCrAl alloys exhibited comparable material loss to a conventional nickel-based alloy, positioning them as viable candidates for this application with the potential to reduce material costs. However, significant internal Al-nitridation was observed for this material, and further studies are required in order to understand its impact on the materials' corrosive protective properties. Lastly, the results observed in this study underscore that corrosion rather than erosion is the principal driving force for the observed material losses, highlighting the importance of considering corrosion mitigation strategies when choosing suitable materials for this application. Additionally, a time-resolved laboratory study was carried out to investigate the corrosive nature of PbCl2(s) on low-alloyed steel at 400°C in a humid environment. Based on the findings presented in this work, it was shown that the presence of PbCl2(s) significantly accelerated the corrosion rate of the steel substrate. The corrosion attack is argued to be driven by the extreme reactivity of PbCl2(s) in the studied environment which leads to a local release of HCl(g) and the introduction of metal chlorides to the metal/oxide interface that promotes severe delamination, void formation, and development of cracks within the oxide scale. The results suggests that Cl plays a pivotal role in both the initiating and propagating corrosion mechanisms of PbCl2-induced corrosion on low-alloyed steels, whereas the Pb compound in PbCl2 do not demonstrate any corrosion-accelerating properties.
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