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Konnektivitetsåtgärder i Emån : En fallstudie vid Högsby vattenkraftverk / Measures for increasing connectivity in Em River : A case study at Högsby hydropower plantKuoljok, Simon Pirak January 2021 (has links)
Den nationella planen för vattenverksamheter antogs år 2020 och innebär att vattenverksamheter ska förses med moderna miljövillkor för att öka vattenmiljönytta och att bibehålla den effektiva tillgången till vattenkraftsel. Emån som är ett Natura 2000-område är det största vattendraget i sydöstra Sverige och vattendraget är utifrån konnektiviteten klassificerat som måttlig. Högsby vattenkraftverk, som ligger i Emån och ägs av Uniper, ska omprövas utifrån miljövillkor enligt den nationella planen och idag har Högsby vattenkraftverk ingen fastställd minimitappning för sin anläggning. Målet med studien är att undersöka storleken på vattenflödet av minimitappningen som kan användas i den ursprungliga naturfåran i Högsby för att möjliggöra longitudinella spridningsmöjligheter i uppströms och nedströms riktning för de fiskarter som historiskt sett har kunnat vandra genom Högsby. En sektion i naturfåran är uppdämd av en tröskeldamm som bedöms vara den svåraste passagen i naturfåran med undantag från utskovsdammen. Metoden som används i rapporten är en endimensionell stationär modellering i HEC-RAS över den naturfåra som kan möjliggöra fiskvandring förbi vattenkraftverk. Två modeller har skapats – med och utan tröskeldamm. Utifrån resultatet är den högsta medelvattenhastigheten i sektionen nedanför tröskeldammen i båda scenarion, detsamma gäller medelvattendjupet. De konnektivitetshöjande åtgärder som diskuteras är minimitappning och olika fiskvägar i naturfåran för att behålla den historiska forsmiljön som funnits. Både rivning av tröskeldamm och fiskväg runt dammen har diskuterats. Därutöver anses havsöring och lax vara fiskarter som med stor säkerhet har kunnat passera Högsby historiskt sett. Högsby är klass 1 i relativt reglerbidrag, vilket bör tas i beaktning vid bedömning av minimitappning. Det finns osäkerheter med modellen, såsom batymetri och randvillkor samt validering av modellen. Därför går det inte med säkerhet att säga att vattendjup eller vattenhastigheter stämmer överens med verkligheten. Slutsatsen är att det inte heller med säkerhet går att säga vilka fiskarter som historiskt sett har vandrat genom Högsby, inte heller en minimitappning kan fastställas som kan möjliggöra fiskvandring för alla fiskarter. Däremot kommer implementeringen av en fastställd minimitappning och fiskvägar öka konnektiviteten. / In 2020 the national plan for hydropower plants was implemented in Sweden. The national plan aims to increase the environmental standards for hydropower plants for the benefit of the water body and still maintain an efficient access to electricity originated from hydropower. Emån is the largest river in the south-eastern part of Sweden. The river a Natura 2000 area and it is classified as moderate based on connectivity according to environmental norm for rivers and water bodies. Högsby hydropower plant located along Emån is owned by Uniper and are included within the national plan, which indicate that it needs to meet the environmental standard. Högsby hydropower plant currently has no established minimum discharge. The aim of the study is to investigate a minimum discharge for the natural dry stream located in Högsby to enable higher connectivity for the fish species that have historically been able to migrate through Högsby. The natural stream is downstream the spillway dam in Högsby. Within the stream a weir is considered to be the most difficult passage for fish migration, with the exception of the spillway dam. The method used in the report is a one-dimensional steady flow model in HEC-RAS for the natural stream to investigate the possibility for fish migration past the hydropower plant. Two scenarios have been considered – with and without the crest dam present. Based on the result from the model, the highest mean water velocity is the section below the weir for both scenarios and same applies to the mean water depth. Implementation of a minimum discharge and various fish ways in the natural stream is measures for increasing connectivity that are being discussed which would also maintain the rapids that has existed in the stream. The fish ways that have been discussed is based on the scenarios if the weir is present or not. The fish species that with great certainty have been able to migrate through Högsby historically is sea trout and salmon. Högsby hydropower plant have the highest classified regulation of the hydropower plants in Emån which need to be considered when determining minimum discharge. There are a few uncertainties with the hydraulic model such as bathymetry and the boundary conditions. The model is not validated which means that the water depth and the velocity might not reflect the true values. It is not certain which fish species that have migrated through Högsby historically, nor can an established minimum discharge be said to enable fish migration. However, an implementation of a minimum discharge and the fish ways that have been discussed will increase the connectivity in Högsby.
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Modeling, Simulation and Correlation of Drag losses in a Power Transfer Unit of an All- Wheel Drive System / Modellering, simulering och korrelation av dragförluster i en kraftöverföringsenhet i ett fyrhjulsdrivsystemVenkatesan, Balaji Srinivasan January 2020 (has links)
A Power Transfer Unit (PTU) of an All-Wheel Drive System is a hypoid gear transmission unit that distributes the power from the vehicle transmission to all wheels of the vehicle. This thesis aims at increasing the fidelity of the analytical power loss calculation methods through test data correlation and develop a 1D simulation model that can be used to evaluate the drag losses in the PTU at early design stages. Firstly, the analytical methods to predict the frictional losses and oil churning losses due to the hypoid gearset, rolling bearings and seals immersed in oil are studied. Several drag loss tests with different combinations of internal components, bearing preloads and with/without the presence of oil were previously conducted on the PTU at different speeds and temperatures at zero torque. The power losses are computed in ROMAX Energy and Excel using different analytical methods available in the literature for each component in the PTU. Then the results from the drag loss tests are segregated component-wise for data correlation with the losses evaluated previously. Based on the data correlation, modification factors are introduced for all analytical methods to match the segregated test results. The demand in the automotive industry to reduce time to market is high. Hence, system-level simulation was chosen as a solution to assess the system efficiency at early concept design stage, saving a lot of time and aid the detailed design. 1D simulation technique is used to study the total power loss of the PTU to optimize its design. The thesis is aimed at developing a 1D system model of the PTU in a commercial tool called LMS AMESim, to evaluate the total power loss of the unit. Inbuilt component models from the software library are used to build a sketch of a simplified lumped mass model of the physical system. The model is simulated in a time domain temporal analysis. The total power loss results simulated using AMESim are compared to the efficiency tests results conducted at different torque levels and ROMAX results. Comparisons between the simulations and test data shows that the system model is accurate and can be used in predicting the power losses in the PTU in the early design stages. This model can also be used to study the influential factors through sensitivity analysis of different parameters which can be done as an extension to the current scope of this work. / En kraftöverföringsenhet (PTU) i ett fyrhjulsdriftsystem är en hypoidväxellådsöverföringsenhet som fördelar kraften från växellådan till alla hjul i fordonet. Det rapporterade arbetet syftar till att öka konfidensen i de analytiska beräkningsmetoderna för effektförlust genom testdatakorrelation och genom att utveckla en 1D-simuleringsmodell som kan användas för att utvärdera dragförlusterna i PTUn i tidiga designfaser. För det första studeras analysmetoderna för att förutsäga friktionsförluster och plaskförluster på grund av hypoidväxeln, rullager och tätningar nedsänkta i olja. Flera ”Drag Loss”-tester med olika kombinationer av interna komponenter, lagerförspänningar och med / utan närvaro av olja utfördes tidigare på PTU vid olika hastigheter och temperaturer utan pålagt moment. Effektförlusterna beräknas i ROMAX Energy med olika analysmetoder tillgängliga i litteraturen för varje komponent i PTU. Sedan separeras resultaten från dragförlusttesterna komponentmässigt för datakorrelation med de tidigare utvärderade förlusterna. Baserat på datakorrelationen införs modifieringsfaktorer för alla analysmetoder för att matcha de segregerade testresultaten. Efterfrågan inom fordonsindustrin att minska tiden till marknaden är hög. Därför väljs simulering på systemnivå som en lösning för att bedöma systemeffektiviteten i ett tidigt konceptdesignfas, vilket sparar mycket tid och underlättar den detaljerade designen. 1D-simuleringsteknik används för att studera PTUns totala effektförlust för att optimera dess design. Arbetet syftar till att utveckla en 1D-systemmodell av PTU i ett kommersiellt verktyg som heter LMS AMESim, för att utvärdera enhetens totala effektförlust. Inbyggda komponentmodeller från programvarubiblioteket används för att skapa en skiss av en förenklad modell av det fysiska systemet. De totala effektförlusterna beräknade med AMESim jämförs med effektivitetstestresultaten vid olika vridmomentnivåer och ROMAX-resultat. Från korrelationen med testresultaten observeras att systemmodellen är korrekt och kan användas för att förutsäga effektförlusterna i PTU i de tidiga designstadierna. Denna modell kan också användas för att studera de viktigaste faktorerna genom känslighetsanalys av olika parametrar, vilket kan göras som en förlängning av detta arbete.
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Numerical Modeling of River Diversions in the Lower Mississippi RiverPereira, Joao Miguel Faisca Rodrigues 20 May 2011 (has links)
The presence of man-made levees along the Lower Mississippi River (MR) has significantly reduced the River sediment input to the wetlands and much of the River's sediment is now lost to the Gulf of Mexico. The sediment load in the River has also been decreased by dams and river revetments along the Upper MR. Freshwater and sediment diversions are possible options to help combat land loss. Numerical modeling of hydrodynamics and sediment transport of the MR is a useful tool to evaluate restoration projects and to improve our understanding of the resulting River response. The emphasis of this study is on the fate of sand in the river and the distributaries. A 3-D unsteady flow mobile-bed model (ECOMSED; HydroQual 2002) of the Lower MR reach between Belle Chasse (RM 76) and downstream of Main Pass (RM 3) was calibrated using field sediment data from 2008 – 2010 (Nittrouer et al. 2008; Allison, 2010). The model was used to simulate River currents, diversion sand capture efficiency, erosional and depositional patterns with and without diversions over a short period of time (weeks). The introduction of new diversions at different locations, e.g., Myrtle Grove (RM 59) and Belair (RM 65), with different geometries and with different outflows was studied. A 1-D unsteady flow mobile-bed model (CHARIMA; Holly et al. 1990) was used to model the same Lower MR reach. This model was used for longer term simulations (months). The simulated diversions varied from 28 m3/s (1, 000 cfs) to 5, 700 m3/s (200, 000 cfs) for river flows up to 35, 000 m3/s (1.2x106 cfs). The model showed that the smaller diversions had little impact on the downstream sand transport. However, the larger diversions had the following effects: 1) reduction in the slope of the hydraulic grade line downstream of the diversion; 2) reduction in the available energy for transport of sand along distributary channels; 3) reduced sand transport capacity in the main channel downstream of the diversion; 4) increased shoaling downstream of the diversion; and 5) a tendency for erosion and possible head-cutting upstream of the diversion.
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Design, Synthesis, and Monitoring of Light-Activated Motorized NanomachinesChiang, Pinn-Tsong 16 September 2013 (has links)
Our group has developed a family of single molecules termed nanocars, which are aimed at performing controllable motion on surfaces. In this work, a series of light-activated motorized nanomachines incorporated with a MHz frequency light-activated unidirectional rotary motor were designed and synthesized. We hope the light-activated motor can serve as the powering unit for the nanomachines, and perform controllable translational motion on surfaces or in solution.
A series of motorized nanovehicles intended for scanning tunneling microscopy (STM) imaging were designed and synthesized. A p-carborane-wheeled motorized nanocar was synthesized and monitored by STM. Single-molecule imaging was accomplished on a Cu(111) surface. However, further manipulations did lead to motor induced lateral motion. We attributed this result to the strong molecule-surface interactions between the p-carborane-wheeled nanocar and the Cu(111) surface. To fine-tune the molecule-surface interactions, an adamantane-wheeled motorized nanocar and a three-wheel nanoroadster were designed and synthesized. In addition, the STM substrates will be varied and different combinations of molecule-surface interactions will be studied.
As a complimentary imaging method to STM, single-molecule fluorescence microscopy (SMFM) also provides single-molecule level resolution. Unlike STM experiment requires ultra-high vacuum and conductive substrate, SMFM experiment is conducted at ambient conditions and uses non-conductive substrate. This imaging method allows us to study another category of molecule-surface interactions. We plan to design a fluorescent motorized nanocar that is suitable for SMFM studies. However, both the motor and fluorophore are photochemically active molecules. In proximity, some undesired energy transfer or interference could occur. A cyanine 5- (cy5-) tagged motorized nanocar incorporated with the MHz motor was designed and synthesized in order to minimize the potential energy transfer or interference between the motor and the fluorophore. The SMFM study of this cy5-tagged motorized nanocar is currently undergoing.
The design of light-activated motorized nanocar inspired the design of nanosubmarines. We used fluorescence quenching and fluorescence correlation spectroscopy (FCS) to study the diffusion of single molecules. The fluorescence quenching experiments of Ru(bpy)3+2 by a quenching nanosubmarine was conducted, but no motor induced acceleration of the molecule were observed. Another fluorescent nanosubmarine was monitored by FCS, and no increase of diffusion coefficient was found. Finally, a 1-D channel approach was adopted for decreasing the effects of Brownian motion, and acceleration of nanosubmarine was observed.
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1-D simulation of turbocharged SI engines : focusing on a new gas exchange system and knock predictionElmqvist-Möller, Christel January 2006 (has links)
<p>This licentiate thesis concerns one dimensional flow simulation of turbocharged spark ignited engines. The objective has been to contribute to the improvement of turbocharged SI engines’ performance as well as 1 D simulation capabilities.</p><p>Turbocharged engines suffer from poor gas exchange due to the high exhaust pressure created by the turbine. This results in power loss as well as high levels of residual gas, which makes the engine more prone to knock.</p><p>This thesis presents an alternative gas exchange concept, with the aim of removing the high exhaust pressure during the critical periods. This is done by splitting the two exhaust ports into two separate exhaust manifolds.</p><p>The alternative gas exchange study was performed by measurements as well as 1-D simulations. The link between measurements and simulations is very strong, and will be discussed in this thesis.</p><p>As mentioned, turbocharged engines are prone to knock. Hence, finding a method to model knock in 1-D engine simulations would improve the simulation capabilities. In this thesis a 0-D knock model, coupled to the 1-D engine model, is presented</p>
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Simulação e inversão de ondas eletromagnéticas em diferentes meios geológico-geotécnicosGomes, Maria da Graça January 2010 (has links)
Este trabalho trata da simulação da propagação de ondas eletromagnéticas (1-D) em meios geológicos de propriedades físicas conhecidas (espessura, condutividade e permissividade elétrica), do registro das ondas EM refletidas (dados sintéticos) para uma antena receptora, e do uso desse registro em algoritmos de inversão e otimização que procuram estimar as propriedades físicas dos meios geológicos. Adotou-se modelos geológicos estratificados de pequena espessura (< 1,2 m) e altas frequências para a onda eletromagnética (800, 1000 e 1200 MHz). A propagação da onda eletromagnética é modelada por meio da resolução das equações de Maxwell no método FDTD. Os métodos de inversão Quasi-Newton e Otimização Ant Colony modificado são aplicados sobre os dados sintéticos para estimar os parâmetros elétricos para cada camada geológica. Ambos os métodos foram aplicados alternadamente para aumentar a precisão e a convergência ao longo da profundidade. Os métodos de inversão foram capazes de estimar simultaneamente duas propriedades eletromagnéticas do modelo geológico: a permissividade elétrica e a condutividade elétrica. Os métodos de inversão alcançaram bons resultados quando executados simultaneamente sobre os dados sintéticos em 3 diferentes frequências. Exemplos de estimativas dos perfis de condutividade e permissividade elétricas unidimensionais são apresentados, com e sem inserção de ruídos nos dados. Os resultados indicam que a combinação dos métodos de inversão (ACO modificado e Quasi-Newton) pode fornecer bons resultados para as estimativas dos parâmetros físicos de meios geológicos e geotécnicos em meios rasos. Além disso, essa combinação de métodos de inversão abre novas perspectivas para o processamento de dados georradar multi-canais. As investigações também mostram que a simulação dos perfis sintéticos por meio do método FDTD pode propagar erros em espessuras maiores de subsolo, devido ao fato de ser um método explícito. / This work deals with simulation of a 1-D electromagnetic wave propagating into a geological structure of known physical properties (thickness, electric conductivity and permittivity), the record of the reflected EM wave (synthetic data), and the use of these records in inversion and optimization algorithms to estimate back the physical properties of the geological structure. A stratified and thin (< 1.2 m) geological structure was initially constructed in order to be scanned by high frequency EM waves (800, 1000, and 1200 MHz). The EM wave propagation is simulated by Maxwell equations through FDTD method. The Quasi-Newton inversion and Ant Colony Optimization methods were applied into synthetic data to estimate original physical parameters of each geological layer. Both methods were applied in order to increase precision and convergence along depth. These methods were able to simultaneously estimate two physical properties of the geological structure: electrical permittivity and conductivity. The methods showed good results when applied simultaneously upon synthetic data of all three frequencies. Electric permittivity and conductivity profiles are shown with and without noise in the data. The results indicate that combined inversion methods can show good results to estimate physical properties of thin geological and geothecnical structures. The combined inversion methods open new perspectives to multichannel GPR data processing. The investigations also show that simulation of synthetic data through FDTD can propagate errors when dealing with thick geological structures, due to the fact that FDTD is an explicit method.
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Simulação e inversão de ondas eletromagnéticas em diferentes meios geológico-geotécnicosGomes, Maria da Graça January 2010 (has links)
Este trabalho trata da simulação da propagação de ondas eletromagnéticas (1-D) em meios geológicos de propriedades físicas conhecidas (espessura, condutividade e permissividade elétrica), do registro das ondas EM refletidas (dados sintéticos) para uma antena receptora, e do uso desse registro em algoritmos de inversão e otimização que procuram estimar as propriedades físicas dos meios geológicos. Adotou-se modelos geológicos estratificados de pequena espessura (< 1,2 m) e altas frequências para a onda eletromagnética (800, 1000 e 1200 MHz). A propagação da onda eletromagnética é modelada por meio da resolução das equações de Maxwell no método FDTD. Os métodos de inversão Quasi-Newton e Otimização Ant Colony modificado são aplicados sobre os dados sintéticos para estimar os parâmetros elétricos para cada camada geológica. Ambos os métodos foram aplicados alternadamente para aumentar a precisão e a convergência ao longo da profundidade. Os métodos de inversão foram capazes de estimar simultaneamente duas propriedades eletromagnéticas do modelo geológico: a permissividade elétrica e a condutividade elétrica. Os métodos de inversão alcançaram bons resultados quando executados simultaneamente sobre os dados sintéticos em 3 diferentes frequências. Exemplos de estimativas dos perfis de condutividade e permissividade elétricas unidimensionais são apresentados, com e sem inserção de ruídos nos dados. Os resultados indicam que a combinação dos métodos de inversão (ACO modificado e Quasi-Newton) pode fornecer bons resultados para as estimativas dos parâmetros físicos de meios geológicos e geotécnicos em meios rasos. Além disso, essa combinação de métodos de inversão abre novas perspectivas para o processamento de dados georradar multi-canais. As investigações também mostram que a simulação dos perfis sintéticos por meio do método FDTD pode propagar erros em espessuras maiores de subsolo, devido ao fato de ser um método explícito. / This work deals with simulation of a 1-D electromagnetic wave propagating into a geological structure of known physical properties (thickness, electric conductivity and permittivity), the record of the reflected EM wave (synthetic data), and the use of these records in inversion and optimization algorithms to estimate back the physical properties of the geological structure. A stratified and thin (< 1.2 m) geological structure was initially constructed in order to be scanned by high frequency EM waves (800, 1000, and 1200 MHz). The EM wave propagation is simulated by Maxwell equations through FDTD method. The Quasi-Newton inversion and Ant Colony Optimization methods were applied into synthetic data to estimate original physical parameters of each geological layer. Both methods were applied in order to increase precision and convergence along depth. These methods were able to simultaneously estimate two physical properties of the geological structure: electrical permittivity and conductivity. The methods showed good results when applied simultaneously upon synthetic data of all three frequencies. Electric permittivity and conductivity profiles are shown with and without noise in the data. The results indicate that combined inversion methods can show good results to estimate physical properties of thin geological and geothecnical structures. The combined inversion methods open new perspectives to multichannel GPR data processing. The investigations also show that simulation of synthetic data through FDTD can propagate errors when dealing with thick geological structures, due to the fact that FDTD is an explicit method.
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Simulação e inversão de ondas eletromagnéticas em diferentes meios geológico-geotécnicosGomes, Maria da Graça January 2010 (has links)
Este trabalho trata da simulação da propagação de ondas eletromagnéticas (1-D) em meios geológicos de propriedades físicas conhecidas (espessura, condutividade e permissividade elétrica), do registro das ondas EM refletidas (dados sintéticos) para uma antena receptora, e do uso desse registro em algoritmos de inversão e otimização que procuram estimar as propriedades físicas dos meios geológicos. Adotou-se modelos geológicos estratificados de pequena espessura (< 1,2 m) e altas frequências para a onda eletromagnética (800, 1000 e 1200 MHz). A propagação da onda eletromagnética é modelada por meio da resolução das equações de Maxwell no método FDTD. Os métodos de inversão Quasi-Newton e Otimização Ant Colony modificado são aplicados sobre os dados sintéticos para estimar os parâmetros elétricos para cada camada geológica. Ambos os métodos foram aplicados alternadamente para aumentar a precisão e a convergência ao longo da profundidade. Os métodos de inversão foram capazes de estimar simultaneamente duas propriedades eletromagnéticas do modelo geológico: a permissividade elétrica e a condutividade elétrica. Os métodos de inversão alcançaram bons resultados quando executados simultaneamente sobre os dados sintéticos em 3 diferentes frequências. Exemplos de estimativas dos perfis de condutividade e permissividade elétricas unidimensionais são apresentados, com e sem inserção de ruídos nos dados. Os resultados indicam que a combinação dos métodos de inversão (ACO modificado e Quasi-Newton) pode fornecer bons resultados para as estimativas dos parâmetros físicos de meios geológicos e geotécnicos em meios rasos. Além disso, essa combinação de métodos de inversão abre novas perspectivas para o processamento de dados georradar multi-canais. As investigações também mostram que a simulação dos perfis sintéticos por meio do método FDTD pode propagar erros em espessuras maiores de subsolo, devido ao fato de ser um método explícito. / This work deals with simulation of a 1-D electromagnetic wave propagating into a geological structure of known physical properties (thickness, electric conductivity and permittivity), the record of the reflected EM wave (synthetic data), and the use of these records in inversion and optimization algorithms to estimate back the physical properties of the geological structure. A stratified and thin (< 1.2 m) geological structure was initially constructed in order to be scanned by high frequency EM waves (800, 1000, and 1200 MHz). The EM wave propagation is simulated by Maxwell equations through FDTD method. The Quasi-Newton inversion and Ant Colony Optimization methods were applied into synthetic data to estimate original physical parameters of each geological layer. Both methods were applied in order to increase precision and convergence along depth. These methods were able to simultaneously estimate two physical properties of the geological structure: electrical permittivity and conductivity. The methods showed good results when applied simultaneously upon synthetic data of all three frequencies. Electric permittivity and conductivity profiles are shown with and without noise in the data. The results indicate that combined inversion methods can show good results to estimate physical properties of thin geological and geothecnical structures. The combined inversion methods open new perspectives to multichannel GPR data processing. The investigations also show that simulation of synthetic data through FDTD can propagate errors when dealing with thick geological structures, due to the fact that FDTD is an explicit method.
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1-D simulation of turbocharged SI engines : focusing on a new gas exchange system and knock predictionElmqvist-Möller, Christel January 2006 (has links)
This licentiate thesis concerns one dimensional flow simulation of turbocharged spark ignited engines. The objective has been to contribute to the improvement of turbocharged SI engines’ performance as well as 1 D simulation capabilities. Turbocharged engines suffer from poor gas exchange due to the high exhaust pressure created by the turbine. This results in power loss as well as high levels of residual gas, which makes the engine more prone to knock. This thesis presents an alternative gas exchange concept, with the aim of removing the high exhaust pressure during the critical periods. This is done by splitting the two exhaust ports into two separate exhaust manifolds. The alternative gas exchange study was performed by measurements as well as 1-D simulations. The link between measurements and simulations is very strong, and will be discussed in this thesis. As mentioned, turbocharged engines are prone to knock. Hence, finding a method to model knock in 1-D engine simulations would improve the simulation capabilities. In this thesis a 0-D knock model, coupled to the 1-D engine model, is presented / QC 20101112
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A Mathematical Model for Carbon NanoscrollsNixdorf, Timothy Allen 16 September 2014 (has links)
No description available.
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