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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