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In the last few decades India has advanced socioeconomically due to the rapid growth of industries and automobile sector. This in turn increases the use of fossil fuel and diesel. The atmosphere gets polluted due to the harmful substances, which comes from the burning of fuel. These pollutants can be in the form of gaseous, liquid or solid particulate. Diesel engines, the major source of power in industries and automobiles, play a significant part in causing air pollution. The major pollutants in diesel exhaust are oxides of nitrogen (NOX), sulphur dioxide (SO2), carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), volatile organic compounds (VOC), aldehydes and alcohols. Due to the heavy consumption of diesel as a fuel there is an urgent need to control diesel exhaust. Diesel exhaust is a complex mixture of several gases and fine particles (commonly known as soot) that contains more than 40 toxic air contaminants. Amongst the gaseous pollutants in diesel exhaust, the major concern and a challenging task is to control oxides of nitrogen, commonly referred to as NOX as it is the major contributor for acid rain, photochemical smog etc. Successful control of emissions from diesel engines is yet to be achieved. The conventional techniques which are available to control emission now are either difficult to operate or does not satisfy the stringent emission standards. This has made the researchers throughout the world to find an alternative and effective non-conventional after treatment technique to reduce diesel engine emission. The failure of conventional techniques lead to the development of non-conventional techniques such as high voltage electric discharge based plasma which has already been proved to be economical and highly efficient in industrial electrostatic precipitators. Electric discharge plasma or non-thermal plasma produce energetic electrons which react with background molecules in flue gas leading to active species such as radicals. These radicals being chemically active selectively react with the harmful pollutants facilitating their removal/reduction. The present thesis work is an attempt to provide a technical solution to achieve higher removal efficiencies of oxides of nitrogen in the backdrop of shortcomings that exist in conventional technologies to do so. The current thesis describes the research in four stages: (i) studies on NOX removal from diesel exhaust by cross-flow DBD reactor, where design and fabrication of cross-flow DBD reactor, exhaust treatment using cross-flow DBD reactor and exhaust treatment with cascaded plasma-adsorbent technique is described (ii) studies on NOX removal from diesel exhaust by compact discharge plasma sources, where design and fabrication of high frequency high voltage AC (HVAC) using old television flyback transformer, Design and fabrication of high voltage pulse (HVPulse) using automobile ignition coil, exhaust treatment with both HVPulse and HVAC and exhaust treatment with cascaded plasma-adsorbent technique is described (iii) studies on NOX removal from diesel exhaust using solar powered discharge plasma source is described (iv) studies on the NOX removal from diesel exhaust using red mud, where exhaust treatment with red mud and Exhaust treatment cascaded plasma-red mud is covered. The results have been discussed in light of enhancing the NOX removal efficiency for stationary and automobile engine exhausts.

The subject of this study is the effect of in-cylinder selective non-catalytic reduction (SNCR) of NOx emissions in diesel exhaust gas by means of direct injection of aqueous urea ((NH2)2CO) into the combustion chamber. A single cylinder diesel test engine was modified to accept an electronically controlled secondary common rail injection system to deliver the aqueous urea directly into the cylinder during engine operation. Direct in-cylinder injection was chosen in order to ensure precise delivery of the reducing agent without the risk of any premature reactions taking place. Unlike direct in-cylinder injection of neat water, aqueous urea also works as a reducing agent by breaking down into ammonia (NH3) and Cyanuric Acid ((HOCN)3). These compounds serve as the primary reducing agents in the NOx reduction mechanism explored here. The main reducing agent, aqueous urea, was admixed with glycerol (C3H8O3) in an 80-20 ratio, by weight, to function as a lubricant for the secondary injector. The aqueous urea injection timing and duration is critical to the reduction of NOx emissions due to the dependence of SNCR NOx reduction on critical factors such as temperature, pressure, reducing agent to NOx ratio, Oxygen and radical content, residence time and NH3 slip. From scoping engine tests at loads of 40 percent and 80 percent at 1500 rpm, an aqueous urea injection strategy was developed. The final injection strategy chosen was four molar ratios, 4.0, 2.0, 1.0 and 0.5 with five varying injection timings of 60, 20, 10, 0, and -30 degrees after top dead center (ATDC). In addition to the base line and aqueous urea tests, water injection and an 80-20 water-glycerol solution reduction agent tests were also conducted to compare the effects of said additives as well. The comparison of baseline and SNCR operation was expected to show that the urea acted as a reducing agent, lowering NOx emissions up to 100% (based on exhaust stream studies) in the diesel exhaust gas without the aid of a catalyst. The data collected from the engine tests showed that the aqueous urea-glycerol solution secondary had no effect on the reduction of NOx and even resulted in an increase of up to 5% in some tests. This was due to the low average in-cylinder temperature as well as a short residence time, prohibiting the reduction reaction from taking place. The neat water and water-glycerol solution secondary injection was found to have a reduction effect of up to 59% on NOx production in the emissions due to the evaporative cooling effect and increased heat capacity of the water.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Even though the Phoenix Metropolitan Area is more fortunate than other areas of the desert southwest because of the dependable Salt and Verde River supplies, they still have water problems. The Central Arizona Project (CAP), which will bring water from the Colorado River, will help those problems. But the CAP will not eliminate them. Improved water resource management will be required to bring water supply and demand back into balance. A key element of any successful water resource management program must be wastewater reuse. The communities are studying reuse through their 208 water quality program and while they are discovering that many opportunities exist they are also discovering that there are also many problems to be solved.

The Atlanta Inspection and Maintenance program ultimately aims to reduce on-road vehicular emission, a major source of air pollution. The program enforces eligible vehicles to be inspected and repaired, if necessary, before the annual registration renewal. However, various factors can influence the program implementation with respect to the motorists, inspectors, and testing technology. This research explores some of these factors by using empirical data from the Continuous Atlanta Fleet Evaluation project, the inspection transaction records, the Atlanta Household Travel Survey, and the U.S. Census Bureau. The study discusses policy implications of findings from the three essays and offers related recommendations. The first essay examines whether the higher income of a vehicle owner decreases the odds of the vehicle failing the first inspection. Findings show that vehicles owned by low-income households are more likely to fail the first inspection of the annual test cycle. However, after controlling for the vehicle characteristics, the odds of failing the first inspection are similar across households. This suggests that the maintenance behaviors are approximately the same for high- and low-income households. The second essay explains the motorists' decisions in selecting their inspection stations using a random utility model. The study finds that motorists are likely to choose the inspection stations that are located near their houses, charge lower fees, and can serve a large number of customers. Motorists are less likely to choose the stations with a relatively high failure ratio especially in an area of low station density. Moreover, motorists do not travel an extra mile to the stations with lower failure ratio. Understanding choices of vehicle owners can shed some light on the performance of inspection stations. The third essay investigates the validity and reliability of the on-board diagnostic generation II (OBD II) test, a new testing technology required for 1966 and newer model year vehicles. The study compares the inspection results with the observed on-road emission using the remote sensing device (RSD) of the same vehicles. This research finds that the agreement between the RSD measurement and the OBD II test is lower for the relatively older or higher use vehicle fleets

Dans ce travail nous avons étudié des réactions chimiques sur la surface de deux métaux :le platine et l'or, en utilisant la microscopie ionique à effet de champ électrique (FIM) et la spectrométrie de masse de désorption par champ pulsé (PFDMS). En complément de ces données expérimentales, nous apportons des résultats obtenus par la théorie de la fonctionnelle de la densité (DFT). La taille et la morphologie de nos échantillons font qu’ils sont de bons modèles de grains de phase active dans un catalyseur réel.<p>\ / Doctorat en sciences, Spécialisation chimie / info:eu-repo/semantics/nonPublished

MENVSC / Department of Ecology and Resource Management / The purpose of this study was to evaluate the strategic management of the Thohoyandou Block J landfill site. There are limited documented materials on strategic management of landfill sites in South Africa. As a result, this study sought to close this gap and expose new insights that it deemed to be of great importance in the management and operations of landfill sites. The capacity of a TBJ landfill site in terms of its efficiency in disposing waste, adherence to rules and procedures and the overall management of the site are the key areas of this study. The dominant types and sources of solid waste disposed at the TBJ landfill site, efficiency and effectiveness of operation of TBJ landfill site and operational challenges are the main areas covered in this study. The study adopted the mixed methods approach, involving both qualitative and quantitative research methods. Both primary and secondary data were acquired. Primary data were obtained through a questionnaire, an interview and field observation, using an observation checklist. Secondary data were obtained from ArcGIS Desktop Help 9.2 and documented materials from the Thulamela Local Municipality and the TBJ landfill site, the Integrated Waste Management Plan, Integrated Development Plan, TBJ landfill site’s monthly report, audit report and landfill site’s operating plan. Basically, field observation and a questionnaire completed by the waste manager, landfill operator and supervisor, were used to collect data on the operational challenges of TBJ landfill site and to obtain data on the efficiency and effectiveness at which the TBJ landfill site is operating. Waste pickers were interviewed and field observation was undertaken, to identify the dominant types and sources of waste disposed at the TBJ landfill site. A questionnaire completed by TBJ landfill operator, ArcGIS Desktop Help 9.2 for field measurement, reports of the amount of waste recorded and the municipality’s database, were utilized to elicit data regarding the determination of the capacity of TBJ landfill site. The results obtained revealed that the TBJ landfill site’s remaining capacity is 317 085 m3, which will be exhausted in the next 4 years. Plastics were found to be the dominant waste disposed at the TBJ landfill site, at 40%, followed by card-boxes, which constituted 32%. The dominant sources of solid waste generation in the TBJ landfill site were households, at 51%, followed by commercial, at 31% and industrial, at 11%. The absence of a weighbridge, to weigh loads of waste, frequent break down of equipment, lack of equipment required to operate the TBJ landfill site efficiently and the presence of fire hazards, were some of the / NRF

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