[pt] A realidade vivida pela população rural tem sempre surpresas a revelar e mais ainda quando se trata do meio rural não eletrificado. Este estudo examina uma parte da realidade do cotidiano vivido por propriedades rurais envolvidas no Programa de Eletrificação Rural Luz no Campo, mostrando o modo de vida das propriedades na fase anterior ao recebimento de energia elétrica. Através do data mining dos dados coletados na pesquisa de campo do estado do Mato Grosso do Sul e da aplicação de técnicas de análise multivariada, tais como: Análise de Fatores e Análise de Cluster, este estudo possibilitará a visualização do modo de vida de propriedades não eletrificadas permitindo posteriormente a comparação com a chegada da energia elétrica que propiciará a avaliação do Programa de Eletrificação Rural. O modelo foi aplicado em dados de duas concessionárias de energia elétrica do Brasil usando dados horários coletados durante dois anos. / [en] The reality lived by the rural population has always some surprises to reveal, even more when it's about the not electrified rural domain. This research examines a part of the reality lived by homestead involved in the Rural Electrification Program Luz no Campo, showing their way of life in the previous phase of the electricity receipt. Through the data mining of the collected data in the field research in Mato Grosso do Sul state and with the application a varied of statistical multivariate techniques such as: Factors Analysis and Cluster Analysis, this research will provide the visualization of the way of life of non electrified properties allowing a later comparison with the data collected in the same properties, after the arrival of the electricity. This way, it will be possible to establish a formal evaluation of the Rural Electrification Program.

<p>Contact electrification of solids in a gas medium involves two stages, i.e., surface charge deposition immediately at separation, and dissipation due to dielectric breakdown of the medium as the gap increases. The presumption that such gas breakdown obeys Paschen's law, which is conventionally determined for gas between electrodes with constant charge supply, is widely accepted yet unverified. The present work experimentally validates such dependence of the breakdown voltage of air between charged dielectric surfaces on both its pressure and the gap distance. Sample surfaces are brought to cycles of contact electrification in a vacuum chamber and charge relaxation due to air breakdown is monitored with measurements of the Coulomb attraction by fixing either the air pressure or gap distance and varying the other. The results indicate thresholds of pressure and distance to facilitate investigations of the raw amount of charge transfer prior to any breakdown discharge, which is adopted to examine the saturation trend of surface charge density in the contact electrification of multiple material combinations using the same test apparatus. Comparatively consistent results are obtained in repeated tests for a variety of contact pairs, while a reduction of saturated surface charge density is observed for PTFE against PDMS after breakdown discharge in low-pressure air, which is preliminarily attributed to alternations of PTFE surfaces caused by accelerated cation strikes during air breakdown, based on SEM images and estimations of particle energy in Townsend avalanches. Conclusions on both the general raw level of surface charge density and the air breakdown during separation in contact electrification are applied to complement models of vibro-impact triboelectric energy harvesters for predicting their performance under various air pressures and physical dimensions in order to either prevent or exploit air breakdown to enhance the power output.</p>

No description available.

Air pollution is one of many issues that have a direct impact upon the economy and the well-being of society in South Africa. Domestic coal combustion contributes significantly to the air pollution problem in the country. Both qualitative and quantitative methods of data collection have been employed in this study. A questionnaire survey was conducted in 100 households in Doornkop (Soweto) and 100 households in KwaGuqa (Witbank). The observations were carried out simultaneously while the questionnaire surveys were being administered in both study areas. Interviews were also held with Eskom (the Electricity Supply Commission of South Africa) officials. Finally, the indoor concentrations and elemental composition of respirable particulate matter (PM7) were measured in three different types of households: electrified without coal burning, electrified with coal burning, and un-electrified with coal burning. The results show that township households, whether electrified or not, continue to burn coal. In both study areas, 80 % of electrified households burn coal for space heating and cooking. Although the major obstacles preventing people from discontinuing domestic coal combustion are poverty and the ready availability and social acceptability of coal, the social value of a fire inside township households cannot be underrated. Previously developed coal-supply networks still exist in the townships and makes coal utilisation very convenient. The findings also point to use of multiple fuels in the communities studied. The key fuels used for domestic energy supply are coal, electricity and paraffin. Emergent patterns of domestic coal combustion, driven in part by various societal dimensions, are also observed. Further, despite the previously observed increase in respiratory ailments in winter, township residents do not think that such increases are linked to domestic coal combustion. The study, as shown here, is in line with theories of the energy ladder which posits that as people’s financial situations improve, their energy-use patterns change. Indoor aerosol concentrations followed the same trends in all selected households with morning and evening peaks. These peaks are directly related to the making of coal fires. The highest aerosol levels, reaching a maximum of 2344.89 μg.m-3, are recorded in the un-electrified coal-burning household. Aerosol concentrations are slightly lower, averaging 1854.07 μg.m-3, in the electrified coal-burning household, implying a slight decrease in the amount of coal burnt. The lowest aerosol concentrations, averaging 478.74 μg.m-3, are recorded in the electrified household with no coal-burning. Elemental analysis reveals that the biggest contributor to respirable particles in KwaGuqa is soil dust followed by coal smoke, and then emissions from neighbouring steel smelters, whilst traffic emissions are the lowest contributor. Most importantly, it is people’s activities that determine the type and levels of respirable aerosols that they are exposed to as compared to the fuel-use patterns and types of fuels used in their household. In conclusion, electrification might phase out domestic coal combustion in the long term but only if the economic status of coal users improves. Alternatively, there is an opportunity to reduce emissions by introducing a low-smoke solid fuel, however, households will only use it if it is priced competitively and its heating and ignition properties are similar to, or better than, those of coal.

Aviation is one of the fastest growing methods of transportation, with passenger volumes expected to triple in the next twenty-five years. It is also contributing an ever increasing share of global emissions. One of the highly effective ways to reduce emissions in aerospace is through electrification. This is already underway with the development and adoption of More Electric Aircraft. A next step is the development of hybrid propulsion, or all electric aircraft, with electric propulsion systems. In order to achieve this goal, the power density of the electric drive is of critical importance. Axial flux permanent magnet synchronous machines have been identified as one the highest power density machine types suitable for these electric drives. In this thesis, an axial flux permanent magnet machine is developed for an electric aircraft propulsion system. A review of electric machines in aerospace applications is conducted, followed by an overview of the design and simulation of axial flux machines, and a presentation of the machine under study. The primary objective of this thesis is to improve the stator design of the axial flux machine by reducing loss, weight, and volume. Magnetic materials are studied, and using grain oriented silicone steel for the stator teeth is shown to improve torque production of the machine. The wire, coil, and stator geometry are modified to reduce copper loss. A tightly spaced coil, axially centered on the tooth, with high aspect ratio wire and chamfered pole shoe is shown to reduce loss. Finally, a compact stator winding is proposed with coil terminations on the inner diameter of the stator. The proposed winding reduces the volume of the machine, as well as further reducing copper loss due to less wire utilized. These actions significantly improve the efficiency of the machine, while reducing weight and volume. / Thesis / Master of Applied Science (MASc)

The value of the surface charge density of polypropylene reported in literature has a three order of magnitude discrepancy. Nauruzbayeva et al report a 0.7nCcm−2 as the surface charge density of polypropylene as measured using the charge of electrified droplets[1]. Meagher and Craig reported result 111nCcm−2 as estimated by electric double layer theory from colloidal probe Atomic force microscopy (AFM) force spectroscopy [2]. We show that oxidation of hydrophobic surfaces as a potential mechanism in origin of these surface charges. Using colloidal probe AFM We measured the surface charge densities of Teflon AF, perfluorodecanethiol, Perfluorodecyltrichlorosilane(FDTS), Octadecyltrichlorosilane, polystyrene, and polypropylene. Also, The pH dependence of the surface charge density for FDTS was studied and it shows the behavior expected of a weak acid in response to pH. We suspect that the origin of the surface charges is mostly likely impurities or surface oxidation. We conclude that the electrometer and dispensed droplets approach cannot detect these charges because of the process of de-wetting all the surface be neutralized to maintain charge neutrality. This explanation supports Nauruzbayeva et al claims about surface bound charges[1].

No description available.

With a clear correlation between climate change and rising CO2 emissions, decarbonization has garnered serious interest in many sectors to limit the adverse effects of global warming. Heating and cooling systems have been a focus of decarbonization efforts, with heat pumps becoming more popular in the United States and abroad. In fact, heating, ventilation, and air conditioning accounts for nearly 27% of total energy use in the United States [1]. Ground source heat pumps (GSHP) utilizing borehole heat exchangers (BHE) have been shown to be an effective method of electrifying heating and cooling systems, maintaining some of the best performance for any electrified heating and cooling system currently available. Electrification, however, does come with some significant challenges. One of particular importance is the significant increase in peak demand during the heating season, which can result in a serious cost increase for the operator of the electric heating system, as well as adding operational complexities to grid operations by shifting from a summer peak to a winter peak as more heating loads are electrified. Thermal energy storage (TES) has been shown to be effective in mitigating the increase in peak demand that is seen with electrified heating and cooling systems. By storing thermal energy during off-peak hours, demand can be effectively shifted away from the peak hours. In this study, we investigate the potential of a ground source heat pump coupled with a TES system, in the form of water storage tanks, for the University of Massachusetts, as a way of decarbonizing the institution’s HVAC system while minimizing operating and installed costs.

This research investigates the effects of both a Hybrid Energy Storage System and an Electrified Turbocharger in a consumer performance vehicle. This research also attempts to support the development of a prototype vehicle containing a Hybrid Energy Storage System currently being developed at McMaster University. Using a custom simulation tool developed in Matlab Simulink, Simulink models of each of the technologies were developed to predict the behavior of these subsystems across multiple physical domains. Control modeling, optimization and testing was completed for both systems. In addition, controls modeling for the Hybrid Energy Storage System was integrated with the development effort for a prototype vehicle considering the specifics of real world components. To assess the impact of these technologies on a performance vehicle platform, the simulation tool tested each technology using multiple vehicle variations. Three vehicle variants were developed, representing: a conventional performance hybrid design, a hybrid vehicle containing an electrified turbocharger, and a vehicle containing a Hybrid Energy Storage System. Electrical system peak output power was the vehicle specification held constant between each vehicle variant. Each vehicle variant was simulated against a number of traditional drive cycles representing everyday driving scenarios in an attempt to compare fuel economy while identifying each technologies individual impact on the vehicles performance. Finally, each vehicle variant was simulated using a custom performance drive cycle in a virtual race. Both technologies as assessed and in comparison to a larger battery variant, did not result in improved fuel economies during conventional vehicle driving. Both the Hybrid Energy Storage System and electrified turbocharger demonstrated improved vehicle performance in particular scenarios. / Thesis / Master of Applied Science (MASc) / Electrified vehicles have not typically been viewed as performance vehicles. A recent trend has seen a growing number of manufacturers turn to hybrid and electric powertrains to produce high performing vehicles. However, a performance vehicle's electrical power is conventionally limited by the size and power of its battery, adding weight and cost. Two technologies offer the ability to increase the power of these electrified components without the need for a large battery. First, Hybrid Energy Storage System combines ultra-capacitors and batteries to increase the power density of the system. Second, an Electrified Turbocharger improves the turbo lag of a turbocharged engine and also recovers waste heat energy from the exhaust gases which is then used to propel the vehicle. This research identifies and demonstrates the potential impact these two technologies have when included in an American Muscle Car.

The transition to a fossil-free industry is a current topic, and in Swedish industry, energytransition of existing energy systems is promoted to reduce climate impact. Energy transitioninvolves a structural change in the energy system with a focus on energy use and energysupply. To reduce global greenhouse gas emissions, the transition can be achieved throughelectrification and the use of biomass. Currently, sawmills combust significant amounts of biomass to meet the heat demandof industrial wood drying. As the biomass used is a by-product of the sawmills’ otherproduction processes, this combustion is usually considered sustainable and circular. However,some research indicates that increased biomass usage in several industrial sectors can leadto overexploitation of the resource with negative environmental impacts. Despite thesedisagreements, many argue that bio-based residual flows must be utilised efficiently to meetsociety’s future biomass needs. Against this background, it needs to be examined whether sawmills should continue tocombust biomass or whether an energy transition would be more economically and ecologicallysustainable. The aim of this study is to investigate how energy use in the sawmill industrywill change in the future and what potential consequences this change may have. In addition,the possibilities and feasibility of electrifying the drying process in the sawmill industryare investigated. To achieve this purpose, a literature search and an interview study wereconducted. The results from these parts form the basis for a scenario-based quantitativestudy of the consequences of different energy transition cases. The results show that future energy use in the sawmill industry will be affected by severalfactors. One important factor is the price of biomass, which can provide an incentive toelectrify the energy-intensive drying process. However, it can be challenging to make anelectrified drying process profitable, and until then energy efficiency will be prioritised ratherthan biomass replacement. The results also indicate that electrification of the drying processcan reduce the climate impact, assuming that the electricity source is fossil-free. The releasedbiomass can then be used more efficiently than incineration, and the optimal use may be toproduce long-life products. Clear knowledge gaps have been identified regarding the electrification of the drying processand its potential consequences. Since the sawmill industry is not ready for an energytransition today, there is time to fill these gaps and develop the electrifying processes. Furtherinvestigations should be conducted on various aspects of electrified drying through in-depthmodelling and analysis of the sawmill energy system. Additionally, future studies couldinvestigate the extent of the impact of sawmill biomass release on the surrounding energysystem.