<p>The aim is to share experience gained when simulating (and doing measurements on) the turbocharged SI-engine as well as describing the limits of current state of the technology. In addition an overview of current boosting systems is provided.</p><p>The target readers of this text are engineers employed in the engine industry as well as academia who will get in contact, or is experienced, with 1D engine performance simulation and/or boosting systems. Therefore the text requires general knowledge about engines.</p><p>The papers included in the thesis are, in reverse chronological order:</p><p>[8] SAE 2005-XX-XXX Calculation accuracy of pulsating flow through the turbine of SI-engine turbochargers - Part 2 Measurements, simulation correlations and conclusions Westin & Ångström</p><p>To be submitted to the 2005 SAE Powertrain and Fluid Systems Conference in San Antonio</p><p>[7] SAE 2005-01-2113 Optimization of Turbocharged Engines’ Transient Response with Application on a Formula SAE / Student engine Westin & Ångström</p><p>Approved for publication at the 2005 SAE Spring Fuels and Lubricants Meeting in Rio de Janeiro</p><p>[6] SAE 2005-01-0222 Calculation accuracy of pulsating flow through the turbine of SI-engine turbochargers - Part 1 Calculations for choice of turbines with different flow characteristics Westin & Ångström</p><p>Published at the 2005 SAE World Congress in Detroit April 11-14, 2005</p><p>[5] SAE 2004-01-0996 Heat Losses from the Turbine of a Turbocharged SI-Engine – Measurements and Simulation Westin, Rosenqvist & Ångström</p><p>Presented at the 2004 SAE World Congress in Detroit March 8-11, 2004</p><p>[4] SAE 2003-01-3124 Simulation of a turbocharged SI-engine with two software and comparison with measured data Westin & Ångström</p><p>Presented at the 2003 SAE Powertrain and Fluid Systems Conference in Pittsburgh</p><p>[3] SIA C06 Correlation between engine simulations and measured data - experiences gained with 1D-simulations of turbocharged SI-engines Westin, Elmqvist & Ångström</p><p>Presented at the SIA International Congress SIMULATION, as essential tool for risk management in industrial product development in Poissy, Paris September 17-18 2003</p><p>[2] IMechE C602/029/2002 A method of investigating the on-engine turbine efficiency combining experiments and modelling Westin & Ångström</p><p>Presented at the 7th International Conference on Turbochargers and Turbocharging in London 14-15 May, 2002</p><p>[1] SAE 2000-01-2840 The Influence of Residual Gases on Knock in Turbocharged SI-Engines Westin, Grandin & Ångström</p><p>Presented at the SAE International Fall Fuels and Lubricants Meeting in Baltimore October 16-19, 2000</p><p>The first step in the investigation about the simulation accuracy was to model the engine as accurately as possible and to correlate it against as accurate measurements as possible. That work is covered in the chapters 3 and 5 and in paper no. 3 in the list above. The scientific contribution here is to isolate the main inaccuracy to the simulation of turbine efficiency.</p><p>In order to have anything to compare the simulated turbine efficiency against, a method was developed that enables calculation of the CA-resolved on-engine turbine efficiency from measured data, with a little support from a few simulated properties. That work was published in papers 2 and 8 and is the main scope of chapter 6 in the thesis. The scientific contributions here are several:</p><p>· The application on a running SI-engine is a first</p><p>· It was proven that CA-resolution is absolutely necessary in order to have a physically and mathematically valid expression for the turbine efficiency. A new definition of the time-varying efficiency is developed.</p><p>· It tests an approach to cover possible mass accumulation in the turbine housing</p><p>· It reveals that the common method for incorporating bearing losses, a constant mechanical efficiency, is too crude.</p><p>The next step was to investigate if different commercial codes differ in the results, even though they use equal theoretical foundation. That work is presented in chapter 4, which corresponds to paper 4. This work has given useful input to the industry in the process of choosing simulation tools.</p><p>The next theory to test was if heat losses were a major reason for the simulation accuracy. The scientific contribution in this part of the work was a model for the heat transport within the turbocharger that was developed, calibrated and incorporated in the simulations. It was concluded that heat losses only contributed to a minor part of the inaccuracy, but that is was a major reason for a common simulation error of the turbine outlet temperature, which is very important when trying to simulate catalyst light off. This work was published in paper 5 and is covered in chapter 7.</p><p>Chapter 8, and papers 6 and 8, covers the last investigation of this work. It is a broad study where the impact of design changes of both manifold at turbines on both simulation accuracy as well as engine performance. The scientific contribution here is that the common theory that the simulation inaccuracy is proportional to the pulsation amplitude of the flow is non-valid. It was shown that the reaction was of minor importance for the efficiency of the turbine in the pulsating engine environment. Furthermore it presents a method to calculate internal flow properties in the turbine, by use of a steady-flow design software in a quasi-steady procedure. Of more direct use for the industry is important information of how to design the manifolds as well as it sheds more light on how the turbine works under unsteady flow, for instance that the throat area is the single most important property of the turbine and that the system has a far larger sensitivity to this parameter than to any other design parameters of the turbine. Furthermore it was proven that the variation among individual turbines is of minor importance, and that the simulation error was of similar magnitude for different turbine manufacturers.</p><p>Paper 7, and chapter 9, cover a simulation exercise where the transient performance of turbocharged engines is optimised with help from factorials. It sorts out the relative importance of several design parameters of turbocharged engines and gives the industry important information of where to put the majority of the work in order to maximize the efficiency in the optimisation process.</p><p>Overall, the work presented in this thesis has established a method for calibration of models to measured data in a sequence that makes the process efficient and accurate. It has been shown that use of controllers in this process can save time and effort tenfold or more.</p><p>When designing turbocharged engines the residual gas is a very important factor. It affects both knock sensitivity and the volumetric efficiency. The flow in the cylinder is in its nature of more dimensions than one and is therefore not physically modelled in 1D codes. It is modelled through models of perfect mixing or perfect displacement, or at a certain mix between them. Before the actual project started, the amount of residual gases in an engine was measured and it’s influence on knock was established and quantified. This was the scope of paper 1. This information has been useful when interpreting the model results throughout the entire work.</p>

A spark ignition engine was retrofitted to operate on biogas fuel. Biogas was synthetically generated through the mixing of various pure gases. The air-fuel ratio was accurately controlled using a closed feedback system consisting of flow controllers and a wide range oxygen sensor. A natural gas catalytic converter was implemented with the use of biogas fuel. To achieve full NOx and CO reduction the engine was required to run at a slightly rich equivalence ratio. Methane emissions posed to be the hardest to reduce across the catalyst. The biogas fuel composition had no effect on the catalyst performance. The catalyst performance was only affected by exhaust temperature and equivalence ratio. The catalyst requires tight A/F ratio control for optimal performance. A Catalytic converter can be used to reach low emissions but requires the knowledge of the biogas fuel composition.

A spark ignition engine was retrofitted to operate on biogas fuel. Biogas was synthetically generated through the mixing of various pure gases. The air-fuel ratio was accurately controlled using a closed feedback system consisting of flow controllers and a wide range oxygen sensor. A natural gas catalytic converter was implemented with the use of biogas fuel. To achieve full NOx and CO reduction the engine was required to run at a slightly rich equivalence ratio. Methane emissions posed to be the hardest to reduce across the catalyst. The biogas fuel composition had no effect on the catalyst performance. The catalyst performance was only affected by exhaust temperature and equivalence ratio. The catalyst requires tight A/F ratio control for optimal performance. A Catalytic converter can be used to reach low emissions but requires the knowledge of the biogas fuel composition.

Visuomenėje jaunimo agresyvumas didėja. Nors mokslinėje literatūroje plačiai išnagrinėta paauglių agresyvaus elgesio problema, tačiau beveik nėra tyrimų apie paauglių, turinčių specialiųjų ugdymosi poreikių, agresijos apraiškas specialiojoje mokykloje. Įvairūs pasaulio mokslininkai paauglių agresyvaus elgesio priežastis sieja su biologinėmis, socialinėmis, asmenybės ir psichologinėmis priežastimis Šio tyrimo tikslas ir buvo – išsiaiškinti galimas paauglių agresijos specialiojoje mokykloje formas ir priežastis. Kelti uždaviniai – 1. Išanalizuoti agresijos aiškinimo teorijas. 2. Išsiaiškinti paauglių agresyvaus elgesio sąsajas su psichologinės raidos ypatumais 3. Apibūdinti paauglių, turinčių specialiųjų ugdymosi poreikių, negalės ir agresyvaus elgesio ryšį. 4. Nustatyti paauglių agresijos apraiškų kilmę ir veiksnius,įtakojančius jų agresyvų elgesį specialiojoje mokykloje. Tyrimas atliktas 3 specialiosiose mokyklose. Naudoti tyrimo metodai –anoniminės anketos ir pusiau struktūruotas interviu. 50 pedagogų ir kitų specialistų apibūdino 110 specialiųjų mokyklų paauglių. Trys specialieji pedagogai interviu metodu patikslino gautą anketomis informaciją. Nustatyta, kad specialiosiose mokyklose pasitaiko agresijos apraiškų, tačiau jos nėra dažnos. Dažniausiai reiškiasi verbalinė agresija ( keiksmai, pravardžiavimai, erzinimas), mažiausiai fizinė. Negalė nedaro didelės įtakos paauglių agresyvumo apraiškoms specialiojoje mokykloje. Agresyvų elgesį gali įtakoti paauglystės raidos... [toliau žr. visą tekstą] / Aggressiveness of youngsters has been growing in the society. Scientific literature has deeply and widely analyzed the problem of teenagers‘ aggression. However, there are almost no studies on aggression signs in special schools of teenagers having special upbringing needs. Various global scientists relate reasons for teenagers‘ aggression with biological, sociological, personal and psychological problems. The purpose of this study is to explore potential teenagers‘ aggression forms and causes in special schools. The goals are the following: 1. To analyze the theory of aggressiveness. 2. To explore the connections between teenagers’ aggressiveness and psychological development issues. 3. To define the connections between disabilities and aggressiveness of teenagers with special upbringing needs. 4. To determine th origins of aggression manifestations and factors influencing pupils‘ behavior in special schools. The study was carried out in 3 special schools. The methods used for the study – anonymous questionnaires and in-depth interviews. 50 teachers and other specialists described 110 teenagers from special schools. Three teachers helped to revise the information from questionnaires through in-depth interview. It was found that there are aggression sings in special schools, but they are not frequent. The most frequent is verbal aggression (swear-words, passages, raillery), less frequent is physical aggression. Disability has no influence on signs of aggression in special... [to full text]

Pastaruoju metu vis labiau akcentuojamas ne mokymo turinys ar programas, bet mokymo(si) būdai ir metodai, t.y. – kaip mokyti? (Walsh, 2001; Bartkevičienė, 2008; Hargreaves, 2008). Jaunesniame mokykliniame amžiuje vyrauja pažintinis vaiko santykis su aplinka, dėl ko pradinė mokykla yra palankus metas pradėti formuoti asmens mokslinį raštingumą, ugdyti mokslinę kultūrą, pradėti taikyti mokslinio tyrimo metodus, kas neabejotinai plėtoja mokinių pažinimo kompetencijas (Lamanauskas, 2004; Savickaitė, 2005; Vilkonienė, 2005). Atsižvelgiant į tai, tyrimo problema formuluojama klausimu: ar pradinėje mokykloje šiuo metu naudojamų pasaulio pažinimo vadovėlių turinys suteikia palankias galimybes tiriamųjų metodų taikymui ir tuo pačiu – mokinių gamtotyrinės / aplinkotyrinės veiklos aktyvinimui? Lietuvoje nėra atlikta tyrimų, kurių metu būtų aiškintasi ar pasaulio pažinimui skirti vadovėliai skatina tiriamąją mokinių veiklą. Tuo pasireiškia šio tyrimo naujumas. Tyrimo objektas: I-IV klasių pasaulio pažinimo vadovėlių turinys tiriamųjų mokymo(si) metodų taikymo aspektu. Darbo tikslas: įvertinti I-IV klasių pasaulio pažinimo vadovėlių teikiamas galimybes taikyti tiriamuosius mokymo(si) metodus. Darbo uždaviniai: 1) Remiantis moksline ir metodine literatūra, atskleisti tiriamųjų mokymo(si) metodų reikšmę ugdymo turinio struktūroje. 2) Mokslinės ir metodinės literatūros analizės pagrindu išskirti vadovėlių turinio vertinimo kriterijus galimybių taikyti tiriamuosius mokymo(si) metodus aspektu... [toliau žr. visą tekstą] / Recently, more and more emphasis is put on the teaching/learning methods and techniques, i.e. “How to teach?”, rather than on the teaching contents or programs (Walsh, 2001; Bartkevičienė, 2008; Hargreaves, 2008). In the young school age, a cognitive child’s relationship with the environment prevails, therefore a primary school is a favourable time to start developing a personal scientific literacy, fostering a scientific culture, and introducing scientific research methods, which undoubtedly develop pupils cognitive competencies (Lamanauskas, 2004; Savickaitė, 2005; Vilkonienė, 2005). With consideration of the above, the research problem is formulated as a question: whether the content of the world cognition textbooks currently used in the primary school provides a favourable context for application of exploratory methods and, at the same time, for activation of the pupils nature research / environmental research activities? No studies have been carried out in Lithuania to investigate, if the world cognition textbooks promote the pupils research activities. This is the novelty of this research. The object of the research: the content of the world cognition textbooks of the 1st-4th forms in the respect of application of exploratory teaching/learning methods. The aim of the thesis: to assess the possibilities provided by the world cognition textbooks of the 1st-4th forms for application of exploratory teaching/learning methods. The targets of the thesis: 1) Based on the... [to full text]

Laikomas įdarbintu, sudarius ir pasirašius darbo sutartį. Darbo sutartis – tai ne tik rašytinis darbo teisinius santykius užfiksuojantis dokumentas, tačiau, pirmiausia, tai tarp šalių susiklostantys tam tikri derybinio pobūdžio ikisutartiniai santykiai, susitarimai, kurių dėka per jų turinį patenkinami ne tik teisėti darbo lūkesčiai, bet užtikrinamas asmens socialinis statusas visuomenėje ir apskritai individuali kiekvieno asmens ir piliečio konstitucinė teisė į darbą ir savišaiška jame. Kelią iki darbo sutarties pasirašymo galima suskirstyti į tokius etapus, kaip teisė į darbo pasirinkimą, kuris turėtų būti aiškinamas ir kaip apimantis darbo paieškas, teisę pasirinkti norimą darbą, teisę į nepriverstinį, savanorišką, teisėtą darbą, taip pat kitą etapą galima išskirti, kaip kiekvieno asmens teisę nustatyti darbo sutarties turinį. Darbo teisėje asmenų lygiateisiškumo principas garantuoja kiekvienam asmeniui, kad darbo sutarties sudarymo stadijoje su juo būtų elgiamasi vienodai, draudžia taikyti jiems skirtingas įdarbinimo sąlygas, tartis dėl tokių sąlygų nustatymo, tapačius santykius vertinti skirtingai dėl asmens lyties, amžiaus, negalios, rasės, etninės priklausomybės, pilietybės bei kitu pagrindu, nesusijusiu su darbuotojų dalykinėmis savybėmis. Asmeniui, patyrusiam diskriminaciją įsidarbinant, turėtų būti prieinamos efektyvios teisinės apsaugos priemonės apginti savo pažeistą individualią teisę būti traktuojamam vienodai lygiai su kitais dėl asmens konstitucinės teisės... [toliau žr. visą tekstą] / A person is considered employed, after the conclusion and signing of an employment contract. The employment concract is not only a written legal labor relations locking document, but first of all, it is some kind of negotiating, contractual relations, agreements evolving among parties, which make satisfied not only legal expectations of the work, but also guarantee an individual’s social status in society and in general each person’s individual and constitutional right to work and express himself at work. The way to the signing of the contract can be divided into the following stages, as the right of the choise of employment, which should be interpreted as covering employment, the right to choose the desired job, the right to non-compulsory, voluntary, legal work, as well as the next stage can be distinguished, as each person’s right to determine the contents of the employment contract. In labor law the principle of equality of persons guarantees to every person to be treated equally, precludes the application of different conditions of employment, to negotiate to estabilish such conditions, to treat identical relations differently based on sex, age, disability, race, ethnicity, nationality and other basis, unrelated to the employee’s professional qualities. The person, who has suffered of discrimination in employment should to be available for an effective, legal protection to defend his damaged individual right to be treated equally with others for his constitutional right... [to full text]

The first project in this work used classical molecular dynamics to study the ice recrystallization inhibition potential of a series of carbohydrates and alcochols, using the hydration index, partial molar volumes and isothermal compressibilities as parameters for measuring their cryogenic efficacy. Unfortunately, after 8 months of testing, this work demonstrates that the accuracy and precision of the density extracted from simulations is not sufficient in providing accurate partial molar volumes. As a result, this work clearly demonstrates that current classical molecular dynamics technology cannot probe the volumetric properties of interest with sufficient accuracy to aid in the research and development of novel cryoprotectants.The second project in this work used molecular dynamics simulations to evaluate the Gibbs free energy change of substituting CO2 in sI clathrate hydrates by N2,CH4, SO2 and H2S flue gas impurities under conditions proposed for CO2 capture (273 K, 10 bar). Our results demonstrate that CO2 substitutions by N2 in the small sI cages were thermodynamically favored. This substitution is problematic in terms of efficient CO2 capture, since the small cages make up 25% of the sI clathrate cages, therefore a significant amount of energy could be spent on removing N2 from the flue gas rather than CO2. The thermodynamics of CO2 substitution by CH4, SO2 and H2S in sI clathrate hydrates was also examined. The substitution of CO2 by these gases in both the small and large cages were determined to be favorable. This suggests that these gases may also disrupt the CO2 capture by sI clathrate hydrates if they are present in large concentrations in the combustion flue stream. Similar substitution thermodynamics at 200 K and 10 bar were also studied. With one exception, we found that the substitution free energies do not significantly change and do not alter the sign of thermodynamics. Thus, using a lower capture temperature does not significantly change the substitution free energies and their implications for CO2 capture by sI clathrate hydrates.

Chemical kinetics has been widely acknowledged as a fundamental theory in analysis of chemical processes and the corresponding reaction outputs and rates. The study and application of chemical kinetics thus provide a simulation tool to predict many characteristics a chemical process. Oxidation of hydrocarbon fuels applied in internal combustion engines is a complex chemical process involving a great number of a series of chained reaction steps and intermediate and simultaneous species. Symbolic and Numerical description of such a chemical process leads to the development and application of chemical kinetics models. The up-to-date application of chemical kinetics models is to the simulation of autoignition process in internal combustion engines. Multi-zone thermodynamic combustion modelling has been regarded as a functional simulation approach to studying combustion process in IC engines as a decent compromise between computation accuracy and efficiency. Integration of chemical kinetics models into multi-zone models is therefore a potential modelling method to investigate the chemical and physical processes of autoignition in engine combustion. This research work has been therefore concerned with the development, validation and application of multi-zone chemical kinetic engine models in the simulation of autoignition driven combustion in SI and HCCI engines. The contribution of this work is primarily made to establish a mathematical model based on the underlying physical and chemical principles of autoignition of the fuel-air mixture in SI and HCCI engines. Then, a computer code package has been developed to numerically solve the model. The derived model aims at improving the understanding of autoignition behaviour under engine-like conditions and providing an investigative tool to autoignition characteristics. Furthermore, as part of the ongoing program in the research of free piston engines, the results of this work will significantly aid in the investigation and simulation of the constant volume autoignition applied in free piston engines.

Silicon-based electrodes are the most promising negative electrodes for the next generation high capacity lithium ion batteries (LIB) as silicon provides a theoretical capacity of 3579 mAh g-1, more than 10 times higher than that of the state-of-the-art graphite negative electrodes. However, silicon-based electrodes suffer from poor cycle life due to large volume expansion and contraction during lithiation/delithiation. In order to improve the electrochemical performance a number of strategies have been employed, such as dispersion of silicon in active/inactive matrixes, devising of novel nanostructures, and various coatings for protection. Amongst these strategies, silicon-carbon coating based composites are one of the most promising because carbon coating is comparatively flexible, easy to obtain, and scalable with various industrial processes. Low cost and renewable lignin, which constitutes up to 30% dry mass of the organic carbon on earth, is widely available from paper and pulp mills which produce lignin in excess of 50 million tons annually worldwide. It is a natural bio-polymer with high carbon content and highly interconnected aromatic network existing as a structural adhesive found in plants. Generally burnt for energy on site, lignin is gradually finding its way into high value-added products such as precursor for carbon fibers, active material in negative electrodes, and raw material for supercapacitors. This dissertation focuses on high performance silicon-based negative electrodes utilizing lignin as the carbon precursor for conductive additive, binder, and carbon coating. To my knowledge this is one of the first works attempting to utilize and summarize the performance of lignin in silicon-based negative electrodes. The first part of the dissertation shows that silicon-lignin composites treated at 800 ºC displayed good capacity and cycling performance. The second part goes to generalize the effect of temperature on silicon-lignin composites and shows that a low temperature treatment granted an electrode with superior performance and cycling properties owing to the preservation of polymeric properties of lignin. The final part of the dissertation discusses the current research trends in SiOx based negative electrodes and extends lignin to that field. This dissertation will, hopefully, provide knowledge and insight for fellow researchers wishing to utilize lignin or other renewable resources in devising advanced battery electrodes.

In striving to produce high quality cast components from recycled aluminium alloys,imperfections have to be considered, because recycled aluminium usually containsmore of it. However, there are great energy savings to be made by using recycledaluminium; as little as 5% of the energy needed for primary aluminium productionmay be required. High quality castings are dependent on, besides alloy chemistry, bothmelt quality and the casting process; the focus of this work is related to the meltquality.This thesis aims to increase knowledge about imperfections, foremost about Fe-richparticles, oxides/bifilms, and porosity. Experiments were performed at industrialfoundry facilities and in a laboratory environment. Melt quality was evaluated byproducing samples with the reduced pressure test (RPT), from which both densityindex (DI) and bifilm index (BI) could be measured, results that were related to tensiletest properties. Data from tensile test samples were analysed, and fracture surfacesand cross sections were studied in both light microscope and in scanning electronmicroscope (SEM). For the purpose of investigating nucleation of primary Fe-richparticles (sludge) differential scanning calorimetry (DSC) was used.In the analysis of results, a correlation between the morphology of particles and tensileproperties were found. And elongated Fe-rich β-particles were seen to fracturethrough cleavage towards the centre. However, DI and BI have not been possible torelate to tensile properties.The nucleation temperature of primary Fe-rich particles were found to increase withincreased Fe, Mn, and Cr contents, i.e. the sludge factor (SF), regardless of cooling rate.For a set SF, an increase of cooling rate will decrease the nucleation temperature.