Dissertations / Theses: 'Charge air'

1

Zhang, Kai. "Air charge system emulation for diesel engine." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521014.

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The work presented in this thesis details a novel engine evaluation approach utilising real-time simulation and advanced engine testing systems for general applicability to new generations of air charging systems. A novel engine air charging system including a charge air handling unit (CAHU) has been developed which is connected to an engine to emulate advanced boosting system conditions. Significant analytical and development work has focused on generating a real-time turbocharger model such that the CAHU can be effectively controlled to emulate the turbocharger performance under both steady and pulsating conditions. Experimental work was carried out to evaluate this new engine air charge testing system against a production turbocharged baseline engine. The accuracies with respect to the boost pressure, turbocharger speed, mass air flow, and fuel consumption in the steady state tests are above 95%, and the level of confidence for the engine back pressure is approximately 90%. The difference of turbocharger speed between the steady turbocharger model and the pulsation model is also identified. In engine transient tests, the boost pressure and engine torque have shown fast response characteristics similar to that of the baseline engine. While general transient trends were achieved, some issues were identified with the high speed control of the CAHU interacting with the dSPACE real time turbocharger model. It is proposed that future improvement can be achieved via applying new control algorithms to improve the accuracy and tracking the CAHU control without increasing the system instabilities.

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Schaal, Peter. "Observer-based engine air charge characterisation : rapid, observer-assisted engine air charge characterisation using a dynamic dual-ramp testing method." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33247.

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Characterisation of modern complex powertrains is a time consuming and expensive process. Little effort has been made to improve the efficiency of testing methodologies used to obtain data for this purpose. Steady-state engine testing is still regarded as the golden standard, where approximately 90% of testing time is wasted waiting for the engine to stabilize. Rapid dynamic engine testing, as a replacement for the conventional steady-state method, has the potential to significantly reduce the time required for characterisation. However, even by using state of the art measurement equipment, dynamic engine testing introduces the problem that certain variables are not directly measurable due to the excitation of the system dynamics. Consequently, it is necessary to develop methods that allow the observation of not directly measurable quantities during transient engine testing. Engine testing for the characterisation of the engine air-path is specifically affected by this problem since the air mass flow entering the cylinder is not directly measurable by any sensor during transient operation. This dissertation presents a comprehensive methodology for engine air charge characterisation using dynamic test data. An observer is developed, which allows observation of the actual air mass flow into the engine during transient operation. The observer is integrated into a dual-ramp testing procedure, which allows the elimination of unaccounted dynamic effects by averaging over the resulting hysteresis. A simulation study on a 1-D gas dynamic engine model investigates the accuracy of the developed methodology. The simulation results show a trade-off between time saving and accuracy. Experimental test result confirm a time saving of 95% compared to conventional steady-state testing and at least 65% compared to quasi steady-state testing while maintaining the accuracy and repeatability of conventional steady-state testing.

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3

Andersson, Per. "Air charge estimation in turbocharged spark ignition engines /." Linköping : Dept. of Electrical Engineering, Linköping University, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/tek989s.pdf.

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4

Wei, Cheng. "Air Induction System (AIS) Optimization." Thesis, KTH, Fordonsdynamik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-198507.

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Air intake system (AIS) plays an important role on affecting the performance of the engine and the vehicle. The design and optimization of the structures and materials of AIS contributes to producing a quality reliable system, reducing noise, cost and weight at the same time, which are significant to improve the performance of engine and vehicle. Fresh air hoses/pipes are intended to transport, in air cleaner purified, air from the air cleaner to the throttle fitted on the inlet manifold or to the compressor fitted to the exhaust manifold. Air cleaner box is responsible for filtering out the dust and impurities in the air. The charge air pipes are intended to transport purified compressed air from the compressor to the charge air cooler and then to the throttle fitted on the inlet pipe. For the air cleaner box optimization, through the benchmarking and the innovation ideas from the daily life, two alternative optimized designs were introduced to reduce the cost and weight. The first is four clips connectors and the other is spring clamps. For the hose clamps, another innovation design was introduced to replace the previous hose clamps, which is called friction connector on the inner side of the bellow hose, the outer side of the air cleaner box lid and the clean side duct. For the material of the charge air ducts, TPEE was selected to replace the previous EACM rubber hoses. Further tests and prototypes should be conducted and produced to verify the effect of the optimization.

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5

McNab, Christopher. "Design optimisation of internally finned tube charge-air coolers." Thesis, University of Brighton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246001.

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6

Mauseth, Frank. "Charge accumulation in rod-plane air gap with covered rod." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1489.

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The focus of this work has been on hybrid insulation in inhomogeneous electric fields under lightning impulse voltage stress. The principal idea behind hybrid insulation is the intentional use of surface charges to re-distribute the electric field within an insulation system. This allows a significant part of the electric stress to be transferred from the dielectric weaker gas to the dielectric stronger solid insulation thus increasing the total electric strength of the insulation system.

The concept has been theoretically and experimentally addressed by means of a hemispheric rod covered with a layer of solid insulation. Discharge activity and surface charge accumulation have been studied in an air gap by measuring the voltage and discharge current and recording the discharge activity using a high-speed digital camera. New methods have been introduced and evaluated for the evaluation of surface charge measurements.

The experiments found that the increase in positive inception voltage was considerable compared to uncovered rods. This increase varied from 35% up to 100% depending on the electrode distance. The increase in breakdown strength is higher than the increase in inception voltage and dependent on the covered length of the rod. During the application of a lightning impulse, the discharge activity spreads upwards along the rod and out into the air gap. Positive discharges form numerous branches and bridge the air gap in most cases. Negative discharges are more diffuse, less light intensive and only form a few branches around the tip of the rod where the electric field is the strongest. Discharge activity along the insulating surface has been observed where the background field is lower than the critical electric field strength. Visible discharge activity is observed where the background field is higher than 2.3 kV/mm and 2.5 kV/mm for positive and negative impulses respectively.

During the application of lightning impulses, discharge activity starts in the air gap around the tip where the electric field is highest and spreads upwards along the rod. As expected, negative charges accumulate on the surface in the case of positive impulse voltage and vice versa. However, after more powerful discharges during negative impulse voltage application, surface charges of both polarities have been observed.

Accumulated surface charges decay exponentially with a time constant τ varying from micro-seconds to hours depending on the material properties of the solid insulation. The dominating relaxation mechanism is found to be conduction through the solid insulation.

Improved methods to calculate surface charges based on probe response for a 2D axial symmetric case have been developed and evaluated. The method that is best suited for this purpose is the λ-method with truncated singular value decomposition (TSVD) as regularization.

Surface charge calculations show that the accumulated surface charges for the used configuration typically have a maximum value of 0.6 to 1.5 µC/m² and 0.4 to 1 µC/m² after positive and negative impulses respectively. The surface charge density in the areas with the highest discharge activity is relatively uniform. Further upwards along the rod, the surface charge density is reduced relatively fast towards zero, and in some cases, it changes polarity before approaching zero.

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7

Bagga, Payel. "Measurement of Electrostatic Dipoles and Net Charge on Air Dispersed Particles." Thesis, University of Canterbury. Chemical and Process Engineering, 2009. http://hdl.handle.net/10092/2992.

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Dipoles are expected to often dramatically enhance the mutual collision rate of diffusing particles (above the effects of Brownian or turbulent motion). However, this spreading awareness of the possible influence of discrete dipoles on particles is still based largely on theory, and some qualitative experience of particle behaviour from microgravity experiments. Individual particle dipoles have not yet been definitely isolated in experiments, nor measured in practical situations. In this project, it was intended to measure, for the first time, distributions of dipole strength (as well as net charge and particle size) on particulates dispersed into air by typical industrial and pharmaceutical processing methods. The instruments designed to do this were built around a sampling head which allowed examination of a flow of dust dispersed into an air stream. During dispersal, the particles suffered tribocharging by mutual separation and collision on walls. Examination of the particles involved recording the path of particles as they moved through a non-uniform electric field around a central electrode, which was supplied with high voltage. Particles were attracted towards the central electrode (of 0.5 mm diameter in this study) if they contained dipoles, independent of the polarity of the field or their net charge. Particles to be examined were illuminated by a laser sheet as they moved past, and a high speed video captured their trajectories (over a field of view of around 5 mm). The equation of motion of a particle which involved the forces of both particle net charge and dipole strength was applied to the particle path to evaluate both these parameters. The particle trajectories were modelled, and checked against the observed experimental trajectories. The voltage applied to the probe varied from 4 kV to 18 kV but for most of the runs 6 kV voltage was used. The electric field around the probe tip was assumed to be same as that for a spherical electrode of the same size as the probe. The flow field axially towards and around the probe tip was calculated using the Stokes creeping flow equations around a sphere. The calculated electric and flow fields were checked against COMSOL Multiphysics models applied to actual geometries and flow regimes. The rotation dynamics of the particles was also considered important in the technique, requiring possibly extra knowledge of the initial direction of the dipole. The flow was led through a lateral field between two plates in order to orient the direction of any dipoles in the direction of the lateral field. The expected orientation of dipoles coming out of the plates was used as an initial guess of their orientation for modelling the rotation of the dipoles when they entered the probe field. Misalignment after leaving the plate field and before entering the probe field was also considered, and was found to be important due to vortices characterised by smoke and particle studies. However, the trajectory modelling revealed that the particles studied quickly rotated into alignment with the probe field, providing maximum attractive force to the probe, and so the values of net charge and dipole strength obtained did not depend on the initial orientation. Estimated errors of particle position and diameter used in all the calculation steps were judged to be well within a basic image error limit of ±1 pixel. Some particle trajectories showed unexplainable shapes which was traced to the influence of large mixing eddies around the gas/particle jet. A check for corona discharge at the probe tip was made both at the beginning and at the end of the sampling experiments. No corona was detected initially (up to 18 kV), but a discharge could be observed at voltages close to 7 kV in the later checks. Particles of acrylic, glass bubbles, whole milk and fertiliser powder were sampled and net charges and dipole charges were estimated. The sampled particles overall had net charge and dipole charge in the range of 10-15 C to 10-12 C on individual particles with diameters 20 μm -130 μm. Dipoles were more evident (more easily measured) for glass bubbles but the presence of dipoles on other particle samples was found and could not be completely ruled out for many of them. The analysis procedure is presently time consuming but can be automated so it is recommended in the future that it should be automated. The work can be extended into industrial situations by sampling moving dust suspensions, e.g. fluid bed overflows and pneumatically conveyed outflows, useful in the dairy and fertilizer industries.

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8

Sharkey, Patrick S. "Optimisation of charge-air coolers for vehicular applications using numerical techniques." Thesis, University of Brighton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309180.

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9

Darlington, Alexander John Veale. "Diesel air-path mean-value modelling and charge properties under transient conditions." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598279.

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Simple mean-value air-path models for modern diesel engines are in common use and have been reported in the literature. This thesis addresses several shortcomings in the models to improve the description of the cylinder charge properties during transient operation. During sudden increases in the demanded engine load, spikes are typically seen in both NO_xand smoke emissions. The predicted cylinder charge properties during the transient are examined and compared with measurements of NO_x and smoke. Together, the emissions data and charge properties paint a consistent picture of the phenomena occurring during the transient. Based on this analysis, alternative strategies for reducing emissions during load transients are developed. Experimental results show that spikes in both NO_x and smoke can be avoided at the expense of some loss in torque response. Even if the torque response must be maintained, it is demonstrated that NO_x spikes can still be eliminated. The air-path model is subsequently extended to include a throttle in the engine intake system. Based on this model, a feed-forward controller is designed to deliver the fastest possible reduction in the in-cylinder air-charge. This type of fast transient may be required to allow regeneration of Lean NO_x Trap exhaust after-treatment systems. The performance of the model based controller is assessed experimentally using a completely novel sampling valve system to measure the in-cylinder gas properties on a cycle-by-cycle basis. When compared with a more conventional approach, the model based controller demonstrates a significantly faster change in the charge properties.

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10

Roache, Kent Arthur. "A study of premixed and stratified charge combustion of CH4/H2/air and H2/air mixtures under constant volume conditions." Thesis, University of Canterbury. Mechanical Engineering, 1988. http://hdl.handle.net/10092/6464.

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The aim of this research was to conduct fundamental charge stratification studies in a constant volume combustion chamber using hydrogen/methane/air and hydrogen/air mixtures. Charge stratification allows the benefits of a rich, or richer, mixture at initiation to be combined with the benefits of a lean overall mixture. Thus benefits can be achieved in terms of combustion efficiency and/or emissions. The investigation was divided into two main sections; the first dealing with the hydrogen enrichment of methane and the second, the reduction of nitric oxide emissions when burning hydrogen only in air. The aim of the first section was to determine the improvements to the combustion characteristics of methane that could be achieved through the homogeneous (pre-mixed) and heterogeneous (stratified charge) addition of hydrogen. The parameters measured were the peak pressure and time to peak pressure while the proportion of hydrogen added was varied. The aim of the second section was an attempt to reduce the concentration of nitric oxide formed during the combustion of hydrogen/air mixtures through the use of charge stratification. The proportion of the hydrogen injected was varied along with the ignition delay in order to alter the level of stratification. The concentration of nitric oxide in the exhaust gases was measured using a mass spectrometer. In addition to the above, optical probes were used to investigate flame propagation and to determine the cause of the 'double hump' pressure trace. For all investigations a cylindrical constant volume combustion chamber of internal volume 2.06 litres was used and the stratified charge was created by injecting pure hydrogen through the core of a specially modified spark plug. Investigations were carried out to improve the level of stratification of the injected hydrogen along with the accuracy of test mixture creation. The results from the first section of this investigation indicate that the addition of hydrogen is a very efficient way of improving combustion characteristics. In particular, significant improvements were observed in the ignition delay and rate of pressure rise leading to higher peak pressures and reduced times to peak pressure. Further benefits were achieved through the use of a stratified charge. Similar improvements to homogeneous charges were observed whilst using up to ten times less hydrogen. The second section indicated that the use of a stratified charge is an effective means for reducing the emissions of nitric oxide. Maximum reduction of nitric oxide (30%) was achieved when igniting the stratified mixture with a minimum ignition delay after the end of injection. An increasing ignition delay leads to a less stratified region and nitric oxide levels tending to homogeneous values. Much work is still required in the area of stratified charge formation and initial results indicate that further improvements could be achieved. In conclusion, this project has indicated that the use of hydrogen enrichment could pave the way for the general acceptance of alternative transport fuels, including hydrogen itself and that the charge stratification concept remains one of the most promising alternatives available for meeting the anticipated environmental and legislative requirements of the future.

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11

Abdelghani-Idrissi, Soufiane. "La charge rapide d'une batterie métal-air par la maîtrise de la fluidique diphasique." Electronic Thesis or Diss., Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLS013.

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La charge rapide des batteries métal-air représente un des verrous technologiques auquel cette technologie est confrontée. Pour répondre à cette problématique, l'électrolyte est soumis à un écoulement pour évacuer les bulles d’oxygène sources d'affaiblissement de l'efficacité de ces batteries. L’écoulement de l'électrolyte permet une réduction du potentiel des électrodes à dégagement de gaz. L’électrode présente une surface active plus élevée, réduisant son potentiel électrique pour un courant donné. La microscopie optique met en évidence le caractère bimodal de la répartition de la taille de bulles qui tend vers une répartition monomodal lorsque le débit augmente. Ces caractérisations électrochimiques et optiques apportent les informations pour développer un modèle analytique pour la prédiction du comportement dynamique de ces systèmes. Ce modèle est complété par une simulation numérique qui met en évidence les phénomènes oscillatoires mesurés à forts courants. L’optimisation énergétique du procédé est réalisée par le choix d’un débit optimal qui concilie le gain en puissance électrique et les pertes de charges hydrauliques. La diminution des pertes par l'adaptation de la géométrie de la cellule d’écoulement a été abordée. La cellule à configuration triangulaire permet une double optimisation énergétique. Ces cellules ont été testées expérimentalement et présentent de meilleures caractéristiques en termes d’évacuation naturelle et forcée des bulles. Une étude préliminaire et les perspectives de l’effet de l’écoulement sur les dendrites de zinc sont présentées. L'écoulement de l'électrolyte dans la cellule augmente le temps de court-circuit
The fast charge of metal-air batteries represent one of the main scientific and technical challenges facing this technology. Oxygen bubbles formed during the charge process has a negative impact on the performances of the cells. Using flowing electrolyte for the evacuation of oxygen bubbles leads to a decrease of the electric potential of the gas evolving electrodes. For a given current, the electrode has more active surface, decreasing its potential. Optical measurement under microscope shows the bimodal distribution of the bubbles sizes. This repartition trends to a uni-modal distribution when the flow rate of the electrolyte increases. Those electrochemical and optical characterizations bring information to develop an analytical modelling for the predictions of the dynamic behavior of these systems. A numerical simulation is also proposed to complete the analytical model. This simulation is able to reproduce the oscillatory behavior at high currents. The optimization of the energy efficiency of the process is done by calculating and choosing an optimal flow rate, corresponding to the best balance between the power gained and the hydraulic power consumed by the flow. The decrease of the hydraulic power needed is done by the adaptation of the geometry of the flow cells. Triangular configuration for the inlet and outlet zones of the flow are tested and shows better characteristics for natural and forced evacuation of the bubbles. A preliminary study and outlooks of the effect of flowing electrolyte on zinc dendrites are presented. Flowing electrolyte increase the time before a short-circuit occurs

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Davids, Sean. "The influence of charge geometry on the response of cylinders to internal air blasting." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20400.

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The effect of charge geometry on the structural response of right circular cylinders, subjected to internal blast loading, was investigated. Thin-walled, seamless 304 stainless steel cylinders were subjected to blast loads from partially confined bare cylindrical PE4 charges with different diameter and aspect ratios(charges length to charge diameter). The diameters of interest were: 25 mm (aspect ratios of 0.5 -3). 30 mm (aspect ratios of 0.5 -1.6). 35 mm (aspect ratios of 0.5 - 1.1). 40 mm (aspect ratios of 0.5 - 0.9). The effect of aspect ratio, for the constant diameter or constant mass cases, on the structural response of the cylinders (that is, diametric deflection, axial impulse, and axial shortening) is reported. Cylindrical charges with an aspect ratio of 1, were compared to spherical charges of equivalent mass. For charges with constant diameter with varying length: The diametric deflection increased with increasing aspect ratio. The axial shortening increased with increasing aspect ratio. The axial impulse increased with increasing aspect ratio. For charges with constant mass with varying diameter and length: The long charges (that is, charges with aspect ratios greater than 1) caused larger diametric deflections than their mass equivalent short (that is, charges with aspect ratios less than 1) charges. This is because the long charges had more side effective charge mass (that is, the mass of the charge that contributes directly to the diametric deflection of a cylinder) than the shorter charges. The short charges transferred more axial impulse to the ballistic pendulum, because they had more axial effective charge mass (that is, the mass of the charge that contributes directly to the axial impulse that is transferred to a ballistic pendulum) than their mass equivalent long charges. It was observed that a lighter charge can diametrically deflect a cylinder more effectively than a heavier charge, if its side effective charge mass is greater than that of the heavier charge. The structural responses of the cylinders obtained from cylindrical charge detonations were greater than those obtained from the mass equivalent spherical charge detonations. The deflections resulting from the cylindrical charges were also more localised compared to the spherical charges.

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13

Turri, R. "The effect of humidity and pressure on space charge growth in high voltage air discharges." Thesis, Swansea University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639277.

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In this thesis the effect of humidity and gas density on discharge development and breakdown characteristics in a short sphere/plane gap subject to positive switching impulses has been investigated. The experiment was carried out in a sealed ionization chamber using laboratory air for pressures in the range 0.7 to 1.4 bar and absolute humidity levels from 2 to 15 g m^-3. Both pressure and humidity could be closely controlled and measured. The impulse shape was = 100/2500 μs and the test gap consisted of a 5 cm diameter sphere 20 cm above an earthed plane. An improved version of biased field-filter and a newly designed composite field/charge probes have been developed, which enabled time-resolved measurements of the electric field distribution at the cathode in the presence of space charge to be made together with a quantitative measurement of the conducted charge in the central region of the cathode. Statistical flashover tests and measurements of apparent charge injection were made and both sets of data were analyzed using a Generalized Liklihood Method, which has been developed during this work and is recommended to be considered for possible adoption as a standard procedure. The breakdown probabilities were found to satisfy a cumulative normal distribution and the charge measurements provided significant additional information at low probability levels. The measured values of V_50 were found to depend linearly upon absolute humidity with a slope of 1.5 kV per g m^-3 at all pressures. The withstand voltages, on the other hand, were only weakly dependent upon absolute humidity. The humidity correction factors found in the present work agree well with the IEC Standards at 1.2 and 1.4 bar, but they depart appreciably at low pressures. In a second series of measurements, simultaneous time-resolved measurements of the light output from the discharge, the apparent charge injection at the HV electrode, the electric field distribution and transfer charge at the cathode, have been made. The results have greatly clarified the mechanism of the space-charge growth in the transition regime from uniform-field to non-uniform-field breakdown, and should enable predictive models of the discharge development and breakdown voltage to be made.

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14

Perrotin, Thomas. "Etude cote air d'échangeurs à haute efficacité énergétique utilisés dans les systèmes de conditionnement d'air résidentiels." Paris, ENMP, 2004. http://www.theses.fr/2004ENMP1239.

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15

Sundelin, Victor, and Filip Jussila. "Estimation of Stability Margins for the Closed-Loop Air Charge Control of an Internal Combustion Engine Using Sinusoidal Disturbances." Thesis, Linköpings universitet, Fordonssystem, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176405.

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The vehicle industry have for many years improved the design of car motors and iterated the control systems associated with it. The systems have become very complex and hard to understand because of this work process. It is today very difficult to perform evaluations of the engine's performance or components theoretically at Powertrain Engineering Sweden (PES). This thesis proposes a test method to estimate the robustness, in terms of stability margins, of the air charge throttle control loop using measurement data. Alternative test methods are also presented, for example system identification performed with MATLAB's SITB. The proposed test method superimposes a sine wave upon the control signal in a closed loop system. The control signal is measured after it is superimposed and after it have made one round trip around the loop. These two signals is regarded as sine in and sine out. The phase shift and relation in amplitude are estimated from the measurements and the robustness is presented by Bode plots. The method finds the phase shift from the time difference between the zero-crossings of the input- and output signal. The relation in amplitude is found by looking at the total sum of the absolute value sine wave. Extensive testing with different tunings of the P-part of the air charge controller shows that the proposed method correctly identifies if the systems stability margins have become larger or smaller. For nine measurements with different P-tunings it is seen that the magnitude curves stay separate throughout the whole Bode plot. It is also shown that the gain margins are decreasing for every increase in P-value. The overall results and findings in this thesis are promising and can act as a foundation for future thesis' work to come.

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Polander, Lauren E. "Organic charge-transport materials based on oligothiophene and naphthalene diimide: towards ambipolar and air-stable n-channel organic field-effect transistors." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45849.

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To better understand the physical and electronic properties of donor and acceptor-based structures used in organic electronic applications, a variety of oligothiophene and naphthalene diimide-based small conjugated molecules were designed, synthesized, and characterized. The materials were initially synthesized using oxidative copper-chloride coupling reactions, palladium-catalyzed amination reactions, Friedal-Crafts acylations, Negishi coupling reactions, and Stille coupling reactions. Once isolated, the physical properties of the compounds were characterized through a combination of X-ray crystal structure, thermogravimetric analysis, differential scanning calorimetry, UV-vis. absorption spectroscopy, cyclic voltammetry, and differential pulse voltammetry, along with comparison to quantum-chemical calculations. In some cases, the radical cations or radical anions were generated by chemical oxidation and analyzed by vis-NIR spectroscopy. Furthermore, the electronic properties of the materials were investigated through incorporation as solution-processed active layers in organic field-effect transistors. Multiple examples exhibited hole- and / or electron-transport properties with electron mobility values of up to 1.5 cm²V⁻¹s⁻¹, which is among the highest yet reported for an n-channel OFET based on a solution-processed small molecule.

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Vyas, Rushi J. "An embedded, wireless-energy-harvesting platform (E-WEHP) for powering sensors using existing, ambient, wireless signals present in the air." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52291.

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The objective of this research is to develop an embedded, wireless, energy-harvesting prototype (E-WEHP) that can power on and sustain embedded sensing functions using the power present in ambient wireless signals in urban areas. This research is part of a bigger effort towards greening RF circuits and applications in order to reduce their pollution foot-print. Pollution due to modern electronics is primarily caused by non-biodegradable packaging waste and batteries that form a big part of most electronics. Electronic waste can especially be a nuisance in RFID and wireless sensors that are mass-produced and widely-used in consumer items, buildings, industries, agriculture and transportation. The first part of this research effort addresses the issue of minimizing electronic packaging waste by characterizing and using biodegradable substrates such as Paper and Perfluoropolymer (PFA) as a dielectric material in RF circuits. Towards this goal, the first of its kind active wireless sensor modules made of biodegradable paper substrate using a clean and novel inkjet-printing technology is developed and successfully operated in the 900 MHz free ISM band. The second and third part of this research effort addresses the issue of battery waste by investigating the use of ambient solar and wireless radiation for powering RF and embedded electronics for wireless localization and sensing applications without the use of batteries. The second part of this work presents a unique solar-powered tag called SOLTAG that combines solar cells along with an RFID-type powering mechanism to implement a very low-cost, battery-less, semi-passive wireless-tag but with a much longer range than passive EPC-Gen2 RFID tags. A GPS-like, low-cost, vehicle-tracking system based on a received-signal-strength-indication method using SOLTAGs in vehicles and a wireless network of Mica-motes is successfully developed and tested with accuracy down to 1.62 meters The third and main part of this research work presents a novel embedded-wireless-energy-harvesting-prototype (E-WEHP) that can successfully power-on and sustain sensing and M2M peripherals in a 16-bit microcontroller using the power present in ambient, wireless, Digital-TV signals without the use of batteries. This work involves an in-depth characterization of OFDM signals used in Digital-TV broadcasts in Tokyo and Atlanta along with the design and development of the E-WEHP hardware and firmware that exploits the multi-carrier nature of such TV signals for powering itself at a range of over 6 km from the TV broadcast sources. This work opens up the possibility of pervasively powering sensor motes for applications such as environmental sensing, smart homes, structural health monitoring, security and internet of things without the environmental and logistical cost of periodic battery replacement and disposal.

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Kodituwakku, Dinindu. "Effect of cooling charge air on the gas turbine performance and feasibility of using absorption refrigeration in the “Kelanitissa” power station, Sri Lanka." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156054.

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One of the drawbacks of the gas turbine is that performance drops rapidly when ambient air temperature increases. This is a major drawback for gas turbines operated in a tropical country like Sri Lanka. In Colombo, commercial capital of Sri Lanka where this study was carried out, the ambient temperature typically varies between 25 0C and 32 0C. The Kelanitissa gas turbine plant has single shaft gas turbines (GE MS5001 R) operated in open cycle which use diesel as fuel (designed for dual fuel) at a designed heat rate of 13,980 kJ/kWh and an electrical efficiency of 25.8%. The designed exhaust temperature is 513 0C. In this study, Kelanitissa gas turbine unit was used for assessment of the performance with the changes in ambient air temperature. Two approaches were used to study this phenomenon. Firstly, the performance parameters were calculated by using actual data acquired by the operation history of the power plant. Secondly, the performance was analyzed using thermodynamic principles. Then results of the two approaches were compared. The present performance values of the studied gas turbine, when compared to designed values, showed a very poor performance due to predominantly high ambient air temperatures. Originally designed for an efficiency of 25.8%, the maximum efficiency achieved at 33 0C was only 21.2%. This translates into a 4.6 %-point reduction in efficiency at 33 0C ambient temperature. Estimated cooling load for the proposed inlet air cooling is 679.87 RT. Cost per unit cooling load of the reference 2-stage direct-fired absorption system is $751-721 (according to 600RT-700RT). For the worst case scenario the value of $751 per RT and exhaust system constituting 98% of the cost of a market-ready direct fired system (Broad Inc., 2008) can be used. This results in $736/RT as the cost for an absorption chiller system driven by exhaust heat. Total cost for the 679.87 RT system is $ 500,370.72 (Rs. 65Mn). Payback period of the project is 11 years but the present value after 19 years is exceeding the project cost. Present value for 19 years is Rs. 65.86 Mn. Bringing down the temperature from an average of 270C to the ISO value of 15 0C would give Rs. 6 Mn of annual savings.

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Kahandagamage, Gayan. "Analysis of the effect of charge air temperature and humidity on the combustion process of diesel engines at Heladhanavi Power Plant, Puttalam, Sri Lanka." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166176.

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Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka consists of six 18V46 Wartsila turbocharged air cooled engines. Specific fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days. This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity. The effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. It was confirmed the specific fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the losses in the flue gas reduce in night time comparatively to the day time. Finally it can be concluded that under the prevailing ambient conditions in Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity on the combustion process. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factors to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value.

På uppdrag av Högskolan i Gävle

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Di, Pietro Riccardo, Tim Erdmann, Naixiang Wang, Xuhai Liu, David Gräfe, Johannes Lenz, Josef Brandt, et al. "The impact of molecular weight, air exposure and molecular doping on the charge transport properties and electronic defects in dithienyldiketopyrrolopyrrole- thieno[3,2-b]thiophene copolymers." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A36273.

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We performed an in-depth study of high molecular weight poly[3,6-(dithiophene-2-yl)-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene] P(DPP2OD-TT) synthesized through the Stille coupling polycondensation in order to understand the correlation between molecular weight, processing conditions and charge transport. We observed a rapid increase in its aggregation in solution with increasing molecular weight which strongly limits the solubility and processability for weight average molecular weights beyond 200 kg mol⁻¹. This results in severe limitation in the charge transport properties of the polymer. We further observe the presence of bulk electronic defects in all different polymer batches that severely limit the current flow and manifest themselves in organic field effect transistors as apparent charge density dependence of the mobility. These defects are passivated by exposure to an ambient atmosphere, as confirmed by an increase in current and mobility that is no more charge density dependent. This is further confirmed by the result of chemical doping using 2,2-(perfluoronaphthalene-2,6-diylidene)dimalononitrile, F₆TCNNQ, which leads to the filling of the trap states and a higher charge density independent mobility of up to 1 cm2 V⁻¹ s⁻¹.

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Bizzarri, Didier. "Compact air separation system for space launcher." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210488.

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A compact air separator demonstrator based on centrifugally enhanced distillation has been studied. The full size device is meant to be used on board of a Two Stage To Orbit vehicle launcher. The air separation system must be able to extract oxygen in highly concentrated liquid form (LEA, Liquid Enriched Air) from atmospheric air. The LEA is stored before being used in a subsequent rocket propulsion phase by the second stage of the launcher. Two reference vehicles are defined, one with a subsonic first stage and one with a supersonic first stage. In both cases, oxygen collection is performed during a cruise phase (M 0.7 and M 2.5 respectively). The aim of the project is to demonstrate the feasibility of the air separation system, investigate the separation cycle design, and assess that the separator design selected is suitable for the reference vehicles.

The project is described from original base ideas to design, construction, extended testing and analysis of experimental results. Preliminary computations for a realistic layout have been performed and the motivations for the choices made during the process are explained. Test rig design, separator design and technical discussion are provided for a subscale pilot unit. Mass transport parameters and flooding limits have been estimated and experimentally measured. Performance has been assessed and shown to be sufficient for the reference Two Stage To Orbit vehicles. The technology developed is found suitable without further optimization, although some volume and mass reduction would be desirable for the supersonic first stage concept. There are many ways of optimisation that can be further investigated. The aim of this program, however, is not to fully optimize the device, but to demonstrate that a device based on a simple, robust, low-risk design is already suitable for the launch vehicles. On top of that analysis, directions for improvements are suggested and their potentials estimated. A complete assessment of those improvements requires further maturation of the technological concept through further testing and practical implementations.

Directions for future work, general conclusions and a vehicle development roadmap have also been provided.

Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Nasani, Ahmad Muntaser. "Etude des phénomènes électrofluidodynamiques sur les gaz empoussiérés en écoulement turbulent : application au transport pneumatique." Poitiers, 1987. http://www.theses.fr/1987POIT2307.

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Analyse de l'influence de certains parametres sur le processus de tranfert de charges electriques au moment du contact d'une particule solide avec une plaque metallique. Etude de la charge d'impact en fonction de l'inclinaison de la plaque, de sa position et de sa charge initiale. Analyse theorique de l'ensemble des phenomenes d'ehd lies au transport pneumatique, en particulier des chutes de pression. Resultats experimentaux dans le cas de deux phases d'ecoulement : ecoulement en phase diluee et ecoulement en phase dense discontinue

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Ribeyre, Quentin. "Influence de l'humidité de l'air sur la perte de charge d'un dépôt nanostructuré." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0056/document.

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Dans l’industrie, des systèmes de protection collectifs doivent être mis en œuvre pour protéger aussi bien les travailleurs que l’environnement. Des filtres à fibres sont généralement disposés dans les circuits de ventilation générale pour capter ces particules en suspension dans l’air. Les performances de ces media fibreux en termes d’efficacité de collecte et consommation énergétique sont relativement bien documentées lors de leur fonctionnement dans des conditions standards (humidité et température ambiantes). Cependant, peu d’études s’intéressent à l’interaction de l’humidité de l’air avec un dépôt composé de particules nanostructurées collectées par ces media filtrants et son incidence sur l’évolution de la perte de charge. Le travail de thèse a donc consisté dans un premier temps à la mesure d’isothermes de sorption de quatre poudres nanostructurées. Un modèle semi-prédictif d’adsorption-condensation basé sur le modèle GAB et la loi de Kelvin a ensuite été proposé. La seconde partie de l’étude a permis de décrire expérimentalement la variation de perte de charge et d’épaisseur d’un milieu poreux, formé par ces mêmes particules nanostructurées, pour différentes valeurs d’humidité. Grâce à la variation d’épaisseur du milieu déterminée par trigonométrie laser et au modèle d’adsorption-condensation, la porosité pour chaque valeur d’humidité relative a pu être calculée. En incorporant les valeurs de porosité et d’épaisseur dans trois modèles de perte de charge, il a été possible de représenter de façon satisfaisante les résultats expérimentaux. Enfin, une analyse rhéologique des poudres est proposée pour quantifier leur augmentation de cohésion sous humidité
Air quality has emerged as a major public environmental and health issue. Almost all fine particles in the air are man-made or manufactured and there are many questions regarding the impact of ultrafine (<100nm) particles on human health. Thus, in most cases, institutions use large-scale protection equipment to protect workers. These institutions often use particulate air filters placed within the flow of general ventilation. Almost all of the available data corresponds to standard ambient air conditions. Despite this, few studies focus on the interaction of water moisture on the deposit formed by these accumulated nanoparticles and the impact on the pressure drop. The first part of this study consists of the measurement of sorption isotherms of four nanostructured powders. A semi-predictive sorption model based on the theory of the multimolecular adsorption (described by the GAB equation) and on the capillary condensation (Kelvin’s law) was developed. The second part of the study experimentally describes the thickness and pressure drop variation of a porous medium formed by these nanostructured particles for different values of humidity. Through the thickness variation of the media - determined by laser trigonometry - and adsorption-condensation model, the porosity for each humidity value has been calculated. Following this, three pressure drop models available in the literature have been modified by introducing cake thickness and porosity variation according to relative humidity. This allows us to model the experimental data for all the samples. Finally, a rheological analysis of powders is proposed to quantify the cohesion changes under moisture conditions

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Dabrowski, Tatjana [Verfasser], Matthias [Akademischer Betreuer] [Gutachter] Busse, and Michael [Gutachter] Moseler. "Atomistic modeling of the charge process and optimization of catalysts positioning in porous cathodes of lithium/air batteries / Tatjana Dabrowski. Betreuer: Matthias Busse. Gutachter: Matthias Busse ; Michael Moseler." Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1102308854/34.

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Paubel, Pierre-Vincent. "Évaluation d’un système de résolution de conflits, ERASMUS : apport de l’oculométrie comme mesure de la charge mentale chez les contrôleurs aériens en-route." Thesis, Toulouse 2, 2011. http://www.theses.fr/2011TOU20053/document.

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Le contrôle aérien doit faire face à une forte intensification du trafic aérien. Dans cette situation, la problématique de la charge mentale chez les contrôleurs aériens est une préoccupation majeure pour maintenir le niveau de sécurité actuel. Le système d’aide automatisé ERASMUS a été élaboré afin de réduire la charge mentale chez les contrôleurs aériens. L’objectif d’ERASMUS est de compenser les effets liés à l’intensification du trafic en réduisant de manière subliminale la charge mentale associée à l’augmentation des conflits potentiels. L’objectif principal de cette thèse est de proposer pour la première fois une mesure objective de l’impact du système d’aide ERASMUS sur la charge mentale des contrôleurs aériens. La réalisation de cet objectif a nécessité le développement d’une plateforme originale d’enregistrement et de traitement des mouvements oculaires non intrusive dans un environnement de simulation hautement fidèle. Les mouvements oculaires d’un groupe de contrôleurs aériens experts ont été enregistrés. En accord avec l’hypothèse d’ERASMUS, les résultats ont montré des effets de tailles moyennes à grandes sur l’amplitude des saccades, le temps moyen passé sur les aéronefs et sur la distribution de l’attention allouée à la scène visuelle. De plus, sans ERASMUS, l’augmentation de la densité du trafic a augmenté de manière significative les diamètres pupillaires. A l’opposé, quand ERASMUS est actif, l’intensification du trafic n’a pas impacté significativement les diamètres pupillaires. Nous discutons l’impact d’ERASMUS sur la charge mentale ainsi que l’utilisation des mesures oculométriques dans un environnement de simulation écologique de contrôle aérien
Air Traffic Control has to handle the strong and constant increase in air traffic density. In this context, mental workload experienced by air traffic controllers is a key research concept to maintain the actual safety level. ERASMUS is an automated aid system designed to reduce air traffic controllers’ workload. The purpose of ERASMUS is to compensate the effects of the air traffic growth by reducing the increased mental workload associated with a greater number of potential conflicts. Prior experiments designed to validate the ERASMUS system showed a reduction in ratings of mental workload, but only subjectives measures were used. In the present thesis, the first goal is to complete these first results by providing, for the first time, a real time objective measure of controllers’ mental workload. In this purpose, we had to develop a new non-intrusive eye-tracking platform in a fully realistic simulation environment. The eye movements of seven controllers, placed in a high-fidelity simulation, were recorded. Traffic sequences were manipulated (with vs. without ERASMUS). Consistent with a reduced workload hypothesis, results showed medium to large effects of ERASMUS on the amplitude of saccades, on the time spent gazing aircraft, and on the distribution of attention over the visual scene. Moreover, without ERASMUS, growth in the traffic density significantly increased pupil diameters. In contrast, when ERASMUS was activated, traffic density growth did not impact significantly pupil diameters. Finally, we discuss the impact of ERASMUS on mental workload and the use of pupillometric measures in an ecological air traffic control environment

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Mallat, Charlotte. "Évaluation et mise en évidence des effets de la charge mentale de travail sur l’adaptabilité comportementale et physiologique A curvilinear effect of mental workload on mental effort and behavioral adaptability Time pressure modulates the curvilinear effect of mental workload on behavioral and physiological adaptability Mental workload effect on behavioral and physiological adaptability in air traffic control task." Thesis, Toulouse 2, 2019. http://www.theses.fr/2019TOU20091.

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Face à une évolution technologique croissante centrée sur la conception et l’automatisation pour plus de performance, étudier les effets de la charge mentale de travail sur l’efficience et l’adaptabilité humaine présente un réel intérêt.L’objectif de ce manuscrit est d’évaluer la charge mentale de travail et de mettre en évidence ses effets sur l’efficience, se traduisant par une adaptabilité comportementale et physiologique de l’opérateur. Plus précisément, il s’agit de faire varier les exigences de la tâche (par exemple, la difficulté, la pression temporelle, la complexité) pour évaluer et identifier les effets engendrés sur l’adaptabilité de l’opérateur. L’adaptabilité comportementale était indexée à la performance avec la mise en place de stratégie et l’adaptabilité physiologique à la mobilisation de l’effort mental avec le score de réactivité de la période de pré-éjection. Le premier chapitre démontre un effet curvilinéaire de la charge mentale de travail sur l’adaptabilité comportementale et physiologique, comme postulé par Hancock et Szalma (2006). Le second chapitre met en évidence que la pression temporelle pouvait dans une certaine mesure favoriser l’adaptabilité comportementale, notamment la mise en place de stratégie. Le troisième chapitre montre que les tâches complexes de contrôle du trafic aérien permettent l’activation du compromis performance-effort se traduisant par une adaptabilité comportementale et physiologique de l’opérateur. Ce manuscrit met en lumière l’importance des facteurs humains dans la boucle de conception des environnements de travail, afin de les repenser et/ou de faire intervenir des outils d’aide si nécessaire, au moment le plus opportun et sous sa forme la plus probante, afin de favoriser une charge mentale optimale
Faced with a growing technological evolution-oriented design and automation, studying the effects of mental workload on human efficiency and adaptability arouses genuine interest. The objective of this manuscript is to evaluate the mental workload and to highlight its effects on efficiency, resulting in a behavioral and physiological adaptability of the operator. More precisely, it is a matter of varying the task demand (for example, the difficulty, the temporal pressure, the complexity) to evaluate and identify the effects on the behavioral and physiological adaptability of operator. Behavioral and physiological adaptability was indexed by performance and pre-ejection period reactivity related to effort mobilization. The first article allowed us to highlight a curvilinear effect of mental workload on behavioral and physiological adaptability, as postulated by Hancock and Szalma (2006). The second article has showed that the temporal pressure could to a certain extent promote behavioral adaptability, especially the implementation of strategy. The third article has demonstrated that the air traffic control complex tasks are likely to activate a performance-effort trade-off resulting both behavioral and physiological adaptability of the operator.The applicative purpose of this thesis is to highlight the importance of human factors in the environments design loop, in order to rethink them and/or to bring in tools of help if necessary, at the most opportune moment and in its form the most convincing, in order to promote an optimal mental workload

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Knutsson, Magnus. "Modelling of IC-Engine Intake Noise." Doctoral thesis, Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10549.

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Hemmingsson, Daniel. "Reglerbar kylartäckning - En lösning till isbildningsproblematik i laddluftkylaren." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-28463.

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Denna rapport ingår i ett examensarbete på avancerad nivå inom ämnet produktutveckling.Arbetet innefattar en fallstudie som genomförts vid RTGA, Scania CV AB i Södertälje.Examensarbetet omfattar 30 högskolepoäng och har genomförts av undertecknad,teknologstudent från Mälardalens Högskola vårterminen 2015. Rapporten har upprättats i tvåversioner, en för Scania CV AB respektive en generell version där känslig företagsspecifikinformation har censurerats. I takt med att utvecklingen av motorprestanda fortskrider, med avseende på ökademotoreffekter samt teknikutveckling för emissionsreglering, så ökar också kravet på prestandaför kylsystem som måste klara av att kyla bort högre effekter. Fordonskombinationer medkraftfulla laddluftkylare löper dock stor risk att drabbas av utfälld kondens som fryser till is iladdluftkylaren vid låga omgivningstemperaturer. Isen medför ett tryckfall i laddluftkylarenmed prestandabortfall som följd. Scanias lösning till problematiken är en så kallad kylargardinsom syftar till att reducera kylluftflödet genom laddluftkylaren till den mån att isbildning intesker. Kylargardinen monteras manuellt av föraren framför kylarpaketet dåomgivningstemperaturen understiger 5 °C. Det finns även andra fördelar med att begränsa det yttre kylluftflödet som passerar genomkylarpaketet. Lastbilars kylsystem är i regel överdimensionerade för normala driftfall såsommotorvägskörning vilket betyder att maximal kylning inte krävs vid dessa situationer. Genomatt reducera det yttre kylluftflödet genom kylarpaketet så kan även hela fordonets totalaluftmotstånd reduceras vilket kan utnyttjas i syfte att reducera bränsleförbrukningen. För att erhålla en bra balansgång mellan aerodynamik och kylprestanda samt motverkaproblemet med isbildning i laddluftkylaren fanns därför en önskan om att en reglerbarkylartäckning skulle utvecklas för att kunna reglera kylluftflödet genom fordonets kylarpaketvid behov. Detta arbete innefattar en fallstudie där olika produktutvecklingsverktyg använts för att ta framolika konceptlösningar, anpassade för en specifik lastbil. Datorstödda flödessimuleringarutnyttjas för att utvärdera respektive verifiera konceptens funktion jämfört med olika referensmodeller. Resultatet visar bland annat att det slutgiltiga konceptets funktionsduglighet överensstämmermed den lösning som används idag samt att kylluftflödet inte påverkas nämnvärt då maximalkylkapacitet eftersträvas. Resultatet från den aerodynamiska flödessimuleringen indikerar ävenatt fordonets totala luftmotstånd kan reduceras med - Drag Counts (DC) vid hastigheten90 km/h och 0° vindriktning. Detta medför att bränsleförbrukningen i det specifika driftfallet,enligt tumregel, antas reduceras med - % för det specifika fordonet.
This report is part of a Master thesis project in the subject of Product Development. The workincludes a case study which was carried out at RTGA, Scania CV AB in Södertälje. The workcomprises 30 credits and was conducted by a student from Mälardalen University during thespring semester 2015. The report has been prepared in two versions; one for Scania CV AB anda generalized version where sensitive company specific information has been censored. The development of vehicle engine performance progresses in a rapid pace. This progressinclude increased engine power and improved technical features for emission control. This alsogoes for the requirement on performance of cooling systems in heavy trucks, which has tohandle dissipation of the increased power. Vehicles with powerful charge air coolers however,runs a high risk of being affected by iced condensation in the charge air cooler at low ambienttemperatures. The ice build-up results in a pressure drop in the charge air cooler with a loss ofengine performance as a consequence. Scania's solution to the problem is a so called radiatorblind designed to reduce the cooling air flow through the charge air cooler to the extent thatice build-up does not occur. The blind is mounted manually in front of the cooler package whenthe ambient temperature is expected to be below 5 °C. There are also other advantages to limit the outer cooling air flow passing through the coolingpackage. The cooling systems in heavy trucks are usually oversized for normal operatingconditions such as highway cruising, which means that maximum cooling is not required inthese situations. By reducing the airflow through the cooler package, the vehicle's total airresistance is reduced, which can be utilized in order to reduce fuel consumption. To obtain a good balance between aerodynamics and cooling performance, and to counteractthe problem of ice build-up in the charge air cooler, there was a desire for an adjustable radiatorcoverage which would be able to regulate the airflow through the vehicle's cooling packagewhen needed. This work includes a case study in which various product development tools are used toinvestigate different concept solutions, designated for a specific truck model. Computationalfluid dynamics (CFD) are used to evaluate and validate the concept’s functionality andcomparing them to different reference models. The results reveal that the final concept functionality is consistent with the one used today, andthat the cooling air flow is not significantly affected when maximum cooling capacity is strivedfor. The results of the aerodynamic flow simulation also indicate that the vehicle's total airresistance can be reduced by - Drag Counts (DC) at the speed of 90 km/h and 0° yaw angle.This means that fuel consumption in the specific operating case, as rule of thumb, is assumedto be reduced by - % for the specific vehicle.

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Fatihou, Ali. "Amélioration des performances des matériaux fibreux non-tissés chargés par décharge couronne utilisés pour la filtration de l'air." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2286/document.

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La démarche expérimentale menée dans cette thèse a eu comme objectif l'étude des facteurs qui influent l'efficacité de collecte des médias non-tissés chargés par décharge couronne, utilisés pour la filtration de l'air. Les recherches se sont focalisées sur les techniques faisant appel à la décharge couronne en configuration fil-plan et en configuration triode (électrode duale + grille + plan de masse). L'étude s'est déroulée en trois phases : (1) mise au point de dispositifs expérimentaux pour générer la décharge couronne et mesurer le potentiel électrique à la surface des échantillons chargés ; (2) caractérisation de l'état de charge des médias ; (3) évaluation de l'efficacité de collecte, en corrélation avec les résultats des mesures de charge. La distribution de charges a été plus homogène en configuration triode et le niveau de charge a été meilleur en polarité positive. Le déplacement de l'échantillon dans la zone de décharge électrique permet de mieux uniformiser la distribution de la charge. L'augmentation du courant de décharge et du potentiel de grille permet d'amplifier le niveau de charge des médias, suite à l'intensification du champ électrique moyen entre l'électrode active et le plan de masse (en configuration fil – plan), ou entre la grille et le plan de masse (en configuration triode). L'efficacité de la collecte est meilleure si la charge est uniformément déposée, sous l'action d'un champ électrique plus intense. Elle est plus élevée pour les configurations dites « multicouches » où la captation des particules est améliorée par l'association de plusieurs mécanismes physiques, mettant en jeux des forces électriques et mécaniques
The experimental approach undertaken in this thesis was aimed at the study of the factors affecting the collection efficiency of nonwoven media charged by corona discharge, used for air filtration. Research was focused on techniques using the corona discharge generated by wire-plane and triode configurations (dual electrode + grid + ground plane). The study was conducted in three phases: (1) development of experimental devices to generate corona discharge and measure the electrical potential on the surface of charged samples; (2) characterization of the electrostatic charge state of the media; (3) evaluation of the collection efficiency, correlated with the results of charge measurements. The charge distribution was more homogeneous in triode configuration and the charge level was higher in positive polarity. The sample movement in the electric discharge zone allowed for more uniform distribution of the charge. The increase of the discharge current and gate voltage amplifies the charge level of the media, due to the intensification of the average electric field between the active electrode and the ground plane (configuration wire - plane) or between the gate and the ground plane (in triode configuration). The collection efficiency is better when the charge is uniformly deposited, under the action of a strong electric field. It is higher for the so-called "multi-layer" configurations where the capture of the particles is improved by the combination of several physical mechanisms, involving electrical and mechanical forces

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Matraji, Imad. "Contribution à la commande non linéaire robuste des systèmes d'alimentation en air des piles à combustible de type PEM." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2013. http://tel.archives-ouvertes.fr/tel-00983443.

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La pile à combustible (PàC) est un dispositif qui produit de l'électricité à partir d'une réaction chimique entre l'hydrogène et l'oxygène. Le système à PàC nécessite un certain nombre d'auxiliaires pour fonctionner. Pour cela, un système de commande est indispensable pour optimiser la performance de la PàC.Dans ce travail de thèse, nous nous sommes intéressés à trois types de problématiques de commande de la PàC. La première est celle de l'optimisation de la puissance délivrée par la PàC en contrôlant le rapport d'excès d'oxygène via le débit d'air du compresseur ; en prenant en compte les variations paramétriques, les incertitudes et les perturbations externes. Ce problème est résolu en utilisant la commande non-linéaire par mode glissant d'ordre 2. Deux types d'algorithme sont synthétisés, l'algorithme du mode glissant d'ordre 2 sous-optimal et l'algorithme du Super Twisting adaptatif. Les performances de ces lois de commande ont été validées grâce à un simulateur Hardware In Loop. La deuxième concerne la maximisation de la puissance nette fournie par la pile, tout en maintenant le fonctionnement du compresseur centrifuge dans sa zone nominale et tout en évitant le manque d'oxygène à la cathode, lors des variations rapides de charge. La solution proposée pour résoudre ce problème est un gestionnaire de charge qui consiste en un filtre à coefficient de filtrage ajustable. Deux approches d'ajustement de ce coefficient basées sur la technique de l'Extremum Seeking sont appliquées, comparées et validées expérimentalement. La troisième problématique abordée dans cette thèse est celle de la régulation de la différence de pression entre l'anode et la cathode, lors de variations de charge en présence de variations paramétriques et d'incertitudes. Une solution basée sur un contrôleur multi-variable par mode glissant d'ordre 2 associé à une étude de robustesse est proposée.

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Martin, Caroline. "La gestion de la charge mentale des contrôleurs aériens en-route : apports de l'eye-tracking dans le cadre du projet européen SESAR." Phd thesis, Université Toulouse le Mirail - Toulouse II, 2013. http://tel.archives-ouvertes.fr/tel-00921212.

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Les contrôleurs du trafic aérien ou " aiguilleurs du ciel ", dont l'activité consiste à assurer la sécurité de l'écoulement du trafic aérien, vont bientôt être confrontés à une évolution sans précédent de leur activité de travail. Pour pallier à une évolution de contexte, associée principalement à une augmentation significative du niveau de trafic aérien, la construction d'un nouvel environnement de contrôle induisant l'introduction de nouvelles technologies et de l'automatisation partielle de la tâche de contrôle est visée. Ces perspectives, qui ont pour objectif de diminuer les sollicitations des contrôleurs aériens afin d'augmenter le seuil capacitaire de gestion du trafic aérien, suscitent l'interrogation. Notamment, comment assurer la validation de ces évolutions en vue des objectifs visés ? Ce doctorat porte sur l'étude de la charge mentale de contrôleurs aériens dans différents contextes, afin d'évaluer les effets engendrés par de telles modifications apportées à leur environnement de travail quotidien. L'évaluation proposée repose sur une approche multidimensionnelle centrée sur l'analyse de paramètres oculaires enregistrés grâce à une technique d'eye-tracking dans des situations de contrôle écologiquement valides, en référence à la tâche de contrôle du trafic aérien. La première étude a tout d'abord permis de caractériser la gestion de la charge mentale effectuée par les contrôleurs aériens au cours de leur activité dans une situation nominale (reflétant la situation de contrôle du trafic aérien actuelle). La deuxième étude porte sur les effets générés par l'introduction de nouveaux systèmes informatisés d'aide à la décision induisant une automatisation partielle de la tâche de contrôle. Enfin, la dernière étude souligne l'effet du niveau de formation sur les modes de gestion des ressources cognitives employés par les contrôleurs aériens.

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Liao, Kuo-Jen. "Sensitivity and uncertainty analyses of impacts of climate change on regional air quality." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24822.

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Thesis (Ph.D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Armistead G. Russell; Committee Member: Athanasios Nenes; Committee Member: M. Talat Odman; Committee Member: Michael Bergin; Committee Member: Yuhang Wang.

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Fernandes, Rita. "Efficient Volvo Bus Cooling System,Using Electrical Fans : A comparison between hydraulic and electrical fans." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155901.

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Economical and environmental factors together with energy policies towards more efficient systemsare the driving force for the development of the vehicle industry. Significant changes have beenmade to fulfill new emissions legislation but the basic internal combustion vehicle architecture hasbeen kept. New emission treatment systems that increase the thermal loading of the cooling systemhad been added within the same package envelope as before, which means less space to place coolingfans and a greater need for airflow. Changes in the cooling system, namely the replacement of thehydraulic fan drive system by electrical fans is one of the energy efficient alternatives for severalcity buses under certain environments, like the ”typical red city buses”, well-known in the UnitedKingdom. In this thesis study, hydraulic fans are compared with electrical fans and a road-mapof the benefits and drawbacks of the two systems is developed, based on real traffic performanceperformance data and the results of existing simulations and tests. In addition, new simulations arepresented in order to find the most efficient design for the cooling system as well as a comparisonof these results with previous ones. This road map will be used later by Volvo-Buses Group as atool to better understand in which circumstances electrical fans can be beneficial, in terms of fuelconsumption, noise production, cooling performance, control of the fans and associated costs.

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Avise, Jeremy Charles. "Global change and regional air quality impacts of climate, land-use, and emissions changes /." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Fall2007/J_Avise_120907.pdf.

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Paquette, Dirk. "Organizational change and Canada's air force." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62817.pdf.

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Acosta, Navarro Juan Camilo. "Anthropogenic influence on climate through changes in aerosol emissions from air pollution and land use change." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-137077.

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Particulate matter suspended in air (i.e. aerosol particles) exerts a substantial influence on the climate of our planet and is responsible for causing severe public health problems in many regions across the globe. Human activities have altered the natural and anthropogenic emissions of aerosol particles through direct emissions or indirectly by modifying natural sources. The climate effects of the latter have been largely overlooked. Humans have dramatically altered the land surface of the planet causing changes in natural aerosol emissions from vegetated areas. Regulation on anthropogenic and natural aerosol emissions have the potential to affect the climate on regional to global scales. Furthermore, the regional climate effects of aerosol particles could potentially be very different than the ones caused by other climate forcers (e.g. well mixed greenhouse gases). The main objective of this work was to investigate the climatic effects of land use and air pollution via aerosol changes. Using numerical model simulations it was found that land use changes in the past millennium have likely caused a positive radiative forcing via aerosol climate interactions. The forcing is an order of magnitude smaller and has an opposite sign than the radiative forcing caused by direct aerosol emissions changes from other human activities. The results also indicate that future reductions of fossil fuel aerosols via air quality regulations may lead to an additional warming of the planet by mid-21st century and could also cause an important Arctic amplification of the warming. In addition, the mean position of the intertropical convergence zone and the Asian monsoon appear to be sensitive to aerosol emission reductions from air quality regulations. For these reasons, climate mitigation policies should take into consideration aerosol air pollution, which has not received sufficient attention in the past.

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Василенко, Олег Вадимович. "Совершенствование рабочего процесса двухтактного двигателя с искровым зажиганием и непосредственным впрыском топлива." Thesis, Украинский государственный университет железнодорожного транспорта, 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21849.

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Диссертация на соискание ученой степени кандидата технических наук по специальности 05.05.03 – двигатели и энергетические установки. Национальный технический университет "Харьковский политехнический институт", Харьков, 2016 г. Диссертация посвящена улучшению эколого-экономических показателей двухтактных ДВС с искровым зажиганием путем применение системы непосредственного впрыска топлива в камеру сгорания. На двигателе ДН-4М проведены экспериментальные исследования с расслоением и обеднением топливновоздушного заряда при непосредственном впрыске топлива. Для обеспечения организации расслоенного топливновоздушного заряда применяется клапанная форсунка с модернизированным распылителем (техническая новизна защищена патентом Украины на изобретение), обеспечивающим кумулятивную топливную струю, направленную на поверхность камеры сгорания возле электродов свечи зажигания. На такте сжатия воздушный поток движется над топливной пленкой, где организуется обогащенная топливновоздушная смесь, которая направляется к электродам свечи зажигания. При этом на режимах холостого хода и на частичных нагрузках на момент подачи искры зажигания на периферии топливновоздушной смеси, возле стенок надпоршневого объема, располагается воздушный заряд с продуктами сгорания. Выявлено, что резервами повышения показателей работы двигателя являются снижение тепловых потерь с отработавшими газами и в систему охлаждения. В двухтактных двигателях с искровым зажиганием при непосредственном впрыскивании топлива и с расслоением топливновоздушного заряда при использовании бензо-этанольных смесей обеспечивается устойчивая работа во всем диапазоне нагрузок без изменений регулировочных параметров с более высокими экономическими и экологическими показателями, чем в аналогичных двигателях с внешним смесеобразованием.
Thesis to obtain scientific degree of Candidate of Engineering sciences on the speciality 05.05.03 – engines and power plants. National Technical University "Kharkiv Polytechnic Institute", Kharkov, 2015. The dissertation is devoted to improving environmental and economic performance two-stroke internal combustion engines with spark ignition by the use of direct fuel injection. Determined that a promising way of internal mixing with direct fuel injection is the organization layered fuel-air charge, providing improved environmental and economic performance. The criterion L, which characterizes the stratification of the fuel-air charge, can qualitatively assess the effect of mixing process on the performance of the engine as a whole. A factor Z, which is deter-mined using indicator efficiency two-stroke engine with external mixture formation, which takes into account only that fuel which is involved in the combustion cylinder engine. The use of direct injection petrol bundle of fuel-air charge modes for loading characteristic at n = 3000 rev/min enabled the reduction in fuel con-sumption of 1.83 times at the effective efficiency rjfmax = 0,31, 7-10 times lower harmful substances (CO, CH) in exhaust gases, the use of gasoline-ethanol blends ensured stable operation of the engine in all load range and a high economic and environmental performance than when using carburetor system power.

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Василенко, Олег Вадимович. "Удосконалення робочого процесу двотактного двигуна з іскровим запалюванням і безпосереднім вприскуванням палива." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21826.

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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.03 – двигуни та енергетичні установки. Національний технічний університет "Харківський політехнічний інститут". – Харків, 2016 р. Дисертація присвячена поліпшенню еколого-економічних показників двотактних ДВЗ з іскровим запалюванням шляхом застосування безпосереднього вприскування палива. Визначено, що перспективним способом внутрішнього сумішоутворення при безпосередньому вприскуванні палива є організація розшарованого паливоповітряного заряду, що забезпечує покращення еколого-економічних показників. Запропоновано критерій L, який характеризує рівень розшарування паливоповітряного заряду, дозволяє якісно оцінити вплив процесів сумішоутворення на показники двигуна в цілому. Запропоновано коефіцієнт Z, за допомогою якого визначається індикаторний ККД двотактного двигуна із зовнішнім сумішоутворенням, який враховує тільки те паливо, яке згоряє в циліндрі ДВЗ. Застосування безпосереднього вприскування бензину з розшаруванням паливоповітряного заряду на режимах навантажувальній характеристиці при n = 3000 хв-1 дозволило зменшити в 1,83 рази витрати палива при значенні ефективного ККД ηе max = 0,31, в 7–10 раз знизити вміст шкідливих речовин (СО, СН) у відпрацьованих газах, також використання бензо-етанольних сумішей забезпечило стійку роботу двигуна у всьому діапазоні навантажень та більш високі економічні і екологічні показники, чим при використанні карбюраторної системи живлення.
Thesis to obtain scientific degree of Candidate of Engineering sciences on the speciality 05.05.03 – engines and power plants. National Technical University "Kharkiv Polytechnic Institute", Kharkov, 2015. The dissertation is devoted to improving environmental and economic performance two-stroke internal combustion engines with spark ignition by the use of direct fuel injection. Determined that a promising way of internal mixing with direct fuel injection is the organization layered fuel-air charge, providing improved environmental and economic performance. The criterion L, which characterizes the stratification of the fuel-air charge, can qualitatively assess the effect of mixing process on the performance of the engine as a whole. A factor Z, which is deter-mined using indicator efficiency two-stroke engine with external mixture formation, which takes into account only that fuel which is involved in the combustion cylinder engine. The use of direct injection petrol bundle of fuel-air charge modes for loading characteristic at n = 3000 rev/min enabled the reduction in fuel con-sumption of 1.83 times at the effective efficiency rjfmax = 0,31, 7-10 times lower harmful substances (CO, CH) in exhaust gases, the use of gasoline-ethanol blends ensured stable operation of the engine in all load range and a high economic and environmental performance than when using carburetor system power.

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Lelas, Vedran. "Chance constrained models for air pollution monitoring and control /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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Dimitrova, Asya 1988. "Climate change and health in India : impacts and co-benefits." Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2022. http://hdl.handle.net/10803/673181.

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El primer estudio de esta tesis doctoral demostró que tanto las temperaturas ambientales altas como las bajas y las olas de calor son factores de riesgo de mortalidad por todas las causas en la India, y el riesgo de mortalidad aumenta de manera más pronunciada a temperaturas más altas. El segundo y tercer estudio evaluaron algunos de los beneficios colaterales para la salud relacionados con la contaminación del aire y las compensaciones de la mitigación del cambio climático en la India. Los hallazgos sugirieron que la reducción proyectada de la contaminación del aire ambiental bajo los objetivos del Acuerdo de París puede alargar la esperanza de vida al nacer, reducir la mortalidad prematura y el número de niños con retraso en el crecimiento en la India para 2050 en comparación con los negocios habituales. Sin embargo, los costos de combustible más altos en virtud de los objetivos del Acuerdo de París pueden conducir a una mayor contaminación del aire en los hogares, compensando así por completo los beneficios para el crecimiento lineal infantil de una mejor calidad del aire ambiental. Complementar las medidas de mitigación con el control de la calidad del aire al final de la tubería y las políticas para respaldar el acceso a una cocina limpia puede maximizar los beneficios colaterales para la salud y reducir las compensaciones de mitigación, especialmente entre los más desfavorecidos.
The first study in this PhD thesis demonstrated that both high and low ambient temperatures and heatwaves are risk factors for all-cause mortality in India, with mortality risk increasing more steeply at higher temperatures. The second and third study assessed some of the air pollution related health co-benefits and trade-offs from climate change mitigation in India. Findings suggested that projected reduction of ambient air pollution under the Paris Agreement targets can lengthen life expectancy at birth, reduce premature mortality and the number of stunted children in India by 2050 compared to the business-as-usual. However, higher fuel costs under Paris Agreement targets can lead to higher household air pollution, thus completely offsetting the benefits for child linear growth from improved ambient air quality. Complementing mitigation measures with end-of-pipe air quality control and policies to support access to clean cooking can maximise health co-benefits and reduce mitigation trade-offs, especially among the most disadvantaged.

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Yu, Defen. "Study of electric discharge and space charge formation phenomena in the air gaps of an ice-covered insulator using an icicle/ice-covered plate electrode system = Étude des processus des décharges électriques et formation de charges d'espace dans les intervalles d'air d'un isolateur recouvert de glace à l'aide d'une configuration d'électrodes glaçon/plaque recouverte de glace /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2007. http://theses.uqac.ca.

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Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2007.
La p. de t. porte en outre: Thèse présentée à l'Université du Québec à Chicoutimi comme exigence partielle du doctorat en ingénierie. CaQQUQ Bibliogr.: f. 222-239. Document électronique également accessible en format PDF. CaQQUQ

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Chen, Jack Chi-Mou. "Short-term air quality forecasts for the Pacific Northwest and long-range global change predictions for the U.S." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Spring2007/j_chen_051007.pdf.

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Waddle, Michael N. "Air Force targeting reform : addressing the need for change /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FWaddle.pdf.

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Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, December 2003.
Thesis advisor(s): Anna Simons, Gordon McCormick. Includes bibliographical references (p. 77-78). Also available online.

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Lee, Mark. "Air pollution and climate change effects on grassland ecosystems." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9697.

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Grassland ecosystems extend across a substantial area of the world’s surface, providing many valuable ecosystem services including carbon sequestration, biodiversity preservation and food provision. Global and local environmental changes are anticipated in the future, including shifts in climatic conditions and changes to the composition of the atmosphere. This thesis adds to our understanding of how grassland communities respond to air pollution and climate change using two key methodologies. Firstly, a suite of environmental variables were measured in calcareous grassland ecosystems along transects adjacent to roads. This allowed quantification of plant compositional changes and identification of the likely drivers of plant compositional changes nearer roadsides. Evidence of road-derived changes to air quality, soil biogeochemistry and hydrology at roadsides are presented. The key messages being that road proximity was associated with increased abundances of nitrophilic species and also of species not typical of calcareous habitats. Secondly, a mesotrophic grassland ecosystem was exposed to a factorial combination of end-of-century rainfall regimes (+ 15 % winter rainfall and – 30 % summer rainfall) based on IPCC 4th Assessment projections and nitrogen enrichment. Plant productivity and species composition were resistant to nitrogen enrichment throughout the three year study. Above-ground plant biomass declined in rainfall manipulated plots by the third year, with evidence of increasing forb abundance and declining grass abundance. These data can assist projections of grassland responses to environmental change in the future and inform management decisions aimed at preventing decline in natural grasslands and declines in the ecosystem services that grasslands currently provide.

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Haddad, Elie. "Modélisation zéro-D des écoulements à l’admission d’un moteur à combustion interne. : Application au boîtier papillon et au refroidisseur d’air suralimenté." Thesis, Ecole centrale de Nantes, 2016. http://www.theses.fr/2016ECDN0020.

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La modélisation système d’un moteur à combustion interne est une étape indispensable à la procédure d’évaluation des performances du moteur avant sa mise au point au banc d’essais. En se passant du montage et du démontage des pièces et des capteurs, ainsi que du coût d’opération d’un banc moteur, la simulation permet de réduire le temps et le coût général. Par ailleurs, il est indispensable d’avoir un modèle de simulation fiable qui permet de reproduire le comportement du moteur avec précision et avec un temps de calcul réduit. Ce mémoire se concentre sur deux éléments du système d’admission d’un moteur à combustion interne à allumage commandé : le boîtier papillon, et le Refroidisseur d’Air Suralimenté. De nouveaux modèles à zéro dimension sont développés en se basant sur les résultats du banc d’essai du laboratoire. Tout d’abord un banc d’essai de boîtier papillon est utilisé pour isoler l’écoulement à travers le papillon des phénomènes qui ont lieu dans le moteur et qui pourraient affecter les mesures ou se superposer. Ensuite un banc moteur est utilisé et des essais en régime stabilisé et transitoire sont effectués. Les nouveaux modèles sont introduits dans un logiciel de simulation Amesim et validés par comparaison avec un champ complet de mesures sur le banc moteur. Le nouveau modèle de boîtier papillon améliore la précision et permet de prendre en compte les différentes conditions de fonctionnement du moteur. Le nouveau modèle d’efficacité thermique du Refroidisseur d’Air Suralimenté permet de déterminer la température d’air en sortie de cet élément sous différentes conditions ainsi qu’en régime stabilisé et transitoire. Les nouveaux modèles développés contribuent donc à l’amélioration de la modélisation 0D du système d’admission d’un moteur à combustion interne à allumage commandé
The modeling of an internal combustion engine is an essential step in the process of evaluation of the engine’s performance before using an engine test bench. The simulation allows saving time and costs, which would otherwise result from all the experimental procedures like the use of sensors, the mounting and dismounting of parts and the operational cost of an engine test bench. Nonetheless, it is essential to have a reliable simulation model that can reproduce the engine’s behavior accurately and with a reduced calculation time. This thesis focuses on two elements of the intake system in a spark ignition internal combustion engine: the throttle body, and the charge air cooler. New zero-dimensional models are developed based on experimental results from the laboratory’s test benches. First, an isolated throttle body test bench is used in order to isolate the flow through the throttle valve from external phenomena which occur in an engine and could affect the reliability of the measurements. Then, an engine test bench is used, in order to perform steady and unsteady experiments. The new models are introduced into the simulation software Amesim and validated by comparison with a field of measurements across the whole engine’s range on the test bench. The new model of throttle body improves accuracy and allows taking into account the different operating conditions of the engine. The new thermal efficiency model of the charge air cooler determines the air outlet temperature of this element under different conditions and in steady and unsteady states. Thus, the new models developed contribute to improving the zero dimensional modeling of the intake system of a spark ignition internal combustion engine

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Fyfe-Green, Ian. "A study of the perceptions of air safety and mid-air collision prevention during regulatory change." Thesis, University of Portsmouth, 2018. https://researchportal.port.ac.uk/portal/en/theses/a-study-of-the-perceptions-of-air-safety-and-midair-collision-prevention-during-regulatory-change(34c6a7cd-5ab8-4499-9d88-9815f4e4b89c).html.

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The aviation industry has been subject to a steady change in its regulations; any change, however minor, has the potential to lead to a decrease in safety. In analysing the data associated with near-miss reporting, together with opinions garnered from those within the aviation industry, this research highlights the impact that regulatory change can have on the barriers to mid-air collision. The research is needed now because, over and above the normal level of changes, 'Brexit' will undoubtedly lead to a new regulatory framework, and there has also been an exponential increase in the number of near-misses between drones and aircraft since January 2015. There is a need for more, or better, regulation surrounding drones. The chance of a drone colliding with an aircraft has increased substantially, acknowledged by both UK and EU authorities, and the findings from this research have contributed to their public consultations. This thesis is strategic with respect to regulatory change in general, the conclusions being equally applicable in any aviation scenario. Brexit and drone proliferation are current examples of the need to manage safety through times of regulatory change, the latter being an example of when a lag in regulation change can cause safety to decrease. Notwithstanding the immediacy of this research, the principles laid out in this thesis will apply to the introduction and management of any future changes to aviation regulations. A survey into the perceptions of aviation personnel received 413 responses across 56 countries. The results are analysed quantitatively first, then triangulated with qualitative analysis of free text comments and reports from interviews with key industry representatives. The analysis is further supported by secondary data in the form of nearmiss reports and a case study. A limitation of the study is that, although the survey attracted a global audience, the individual numbers of responses from many countries is not enough to make a representative argument for anything but a global perspective, when a comparison between regions would have been useful.

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Saari, R. K. (Rebecca Kaarina). "Air quality impacts and benefits under U.S. policy for air pollution, climate change, and clean energy." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99563.

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Thesis: Ph. D., Massachusetts Institute of Technology, Engineering Systems Division, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 86-94).
Policies that reduce greenhouse gas emissions can also reduce outdoor levels of air pollutants that harm human health by targeting the same emissions sources. However, the design and scale of these policies can affect the distribution and size of air quality impacts, i.e. who gains from pollution reductions and by how much. Traditional air quality impact analysis seeks to address these questions by estimating pollution changes with regional chemical transport models, then applying economic valuations directly to estimates of reduced health risks. In this dissertation, I incorporate and build on this approach by representing the effect of pollution reductions across regions and income groups within a model of the energy system and economy. This new modeling framework represents how climate change and clean energy policy affect pollutant emissions throughout the economy, and how these emissions then affect human health and economic welfare. This methodology allows this thesis to explore the effect of policy design on the distribution of air quality impacts across regions and income groups in three studies. The first study compares air pollutant emissions under state-level carbon emission limits with regional or national implementation, as proposed in the U.S. EPA Clean Power Plan. It finds that the flexible regional and national implementations lower the costs of compliance more than they adversely affect pollutant emissions. The second study compares the costs and air quality co-benefits of two types of national carbon policy: an energy sector policy, and an economy-wide cap-and-trade program. It finds that air quality impacts can completely offset the costs of a cost-effective carbon policy, primarily through gains in the eastern United States. The final study extends the modeling framework to be able to examine the impacts of ozone policy with household income. It finds that inequality in exposure makes ozone reductions relatively more valuable for low income households. As a whole, this work contributes to literature connecting actions to impacts, and identifies an ongoing need to improve our understanding of the connection between economic activity, policy actions, and pollutant emissions.
by Rebecca Kaarina Saari.
Ph. D.

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Yetiskul, Emine. "Structural Changes in Deregulated Air Transportation Systems." 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/138509.

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Fahrenkrug, David T. "Regime change and the role of airpower." Maxwell Air Force Base, Ala. : School of Advanced Air and Space Studies, Air University, 2003. http://handle.dtic.mil/100.2/ADA425584.

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Kennedy, Kevin B. "Checkmate an organization for air and space strategy /." CLICK HERE TO VIEW:, 2004. https://research.maxwell.af.mil/papers/ay2004/ari/kennedy.pdf.

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Dissertations / Theses on the topic 'Charge air'

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