M. Tech. Engineering Technology . / Demonstrates through design and experiments the heat transfer effectiveness of energy recovery from waste gases by using a heat exchanger. To use the heat exchanger to intercept the waste gases before they leave the process, extract some of the heat in the gases and use the same for preheating/heating the process water. The experiment is also intended to demonstrate whether or not waste heat unit has an effect on the emissions released to the environment. Diesel engines have been widely used in heavy-duty vehicles for their better fuel efficiency and higher power output than gasoline engines. However, the emissions of gas (CO, HC and NOx) and particulate matter (PM) pollutants from the diesel engine receive much concern from the general public and environmental researchers because of the epidemiological and toxicological investigations suggesting a relationship between exhaust pollutants exposure and adverse health effects.

Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: To reduce exhaust gas emissions in diesel engines and for engine upgrade purposes the major parameters and equipment that should be looked at are boost pressure, intake charge temperature, combustion chamber design and fuel injection equipment. Boost pressure is governed by the turbo-charger; with high-efficiency variable geometry turbochargers, effective control is possible to increase airflow rate at all operating conditions of the engine. Efficient air-to-air inter-cooling results in the engine being filled with a cooler air charge that will influence engine durability and heat rejection to the cooling system. The main objective of the investigation is to look at the influence of boost pressure and intake charge temperature on diesel combustion to better understand the processes where boost pressure is increased and intake charge temperature reduced to increase the brake mean effective pressure of the engine and reduce emissions generation. By running an engine at different intake boost pressures and intake charge temperatures a 25-point matrix was formed at three different operating conditions. On completion of the engine testing, data processing and data evaluation, a number of important conclusions were made about the behaviour of the engine running under different conditions. This enabled the researcher to understand how boost pressure and intake charge temperature influence engine power output, fuel consumption, engine durability and exhaust gas emissions. The opinion is proved when, in most cases, the 75 test points were used to build multiple linear regression models to determine which engine parameters (dependent variables) have a significant effect on emissions generation and durability parameters. From the data it is evident that boost pressure has a positive influence on most engine parameters, as an increase in boost pressure results in an increase in air mass flow through the engine. An increase in air mass flow reduces combustion chamber gas temperature as the result of an increase in excess air ratio during combustion. A further result of the increase in excess air ratio is that less soot is formed during the first part of combustion and more soot and partly decomposed Hydrocarbon (HC) compounds are oxidised during the late combustion phase. Therefore, with an increase in boost pressure, Bosch smoke emissions reduce, but with a change in intake air temperature no difference in smoke concentration is seen except at the very low boost pressure and very high boost temperature test points where low air/fuel ratios exist and the slight increase in air-flow rate as a result of lower air inlet temperature has a big influence. Nitric Oxide (NO) emissions, on the other hand, are more dependent on intake air temperature than on boost pressure, which was proved in the multiple regressions modelling performed on the test data. The flame zone and the post-flame zone temperature play the dominant role in NO formation. As explained in the results discussion on NO formation, intake air temperature influences the ignition mixture temperature and the subsequent flame zone temperature. A lower intake air condition results in longer ignition delay and increases the initial rate of combustion. / AFRIKAANSE OPSOMMING: Die hoofparameters en toerusting wat in ag geneem moet word om uitlaatgasemissies in dieselenjins te verminder en om enjinkraguitset te verhoog, is inlaatdruk, inlaat lugtemperatuur, verbrandingskamerontwerp en brandstofinspuittoerusting. Inlaatdruk word beheer deur die turb-aanjaer. Met hoë effektiwiteit, veranderlike geometrie turboaanjaging, is effektiewe beheer moontlik om lugvloei-tempo deur die enjin te verhoog onder alle enjinwerkstoestande. Effektiewe lug-tot-lug tussenverkoeling laat die enjin met koeler inlaatlug vul, wat 'n uitwerking het op enjinlewensduur en hitte-verlies na die verkoelingsstelsel. Die hoofdoel van die navorsing is om die invloed van inlaatdruk en inlaat lugtemperatuur op dieselverbranding te ondersoek. Sodoende kry die navorser 'n beter begrip omtrent die prosesse waar inlaatdruk verhoog en inlaat lugtemperatuur verlaag word, om rem-gemiddelde effektiewe druk van die enjin te verhoog en uitlaatgas emissies te verlaag. 'n 25-punt matriks is opgestel deur die enjin by verskillende inlaatdrukke en inlaat lugtemperture te opereer, en by drie verskillende wringkragwerkstoestande. 'n Aantal belangrike gevolgtrekkings is gemaak omtrent enjinwerking onder verskillende werkstoestande na voltooiing van die enjintoetse, dataverwerking en data-evaluering. Sodoende het die navorser bepaal hoe inlaatdruk en inlaat lugtemperatuur kraglewering, brandstofverbruik, enjinlewensduur en uitlaatgasemissies beïnvloed. Om bogenoemde begrippe verder te ondersteun is 'n meervoudige, lineëre regressiemodel opgestel om te bepaal watter enjinparameters (afhanklike veranderlikes) 'n wesenlike effek op emissiegenerasie en lewensduur het. Van die data word afgelei dat inlaatdruk 'n positiewe effek op die meeste enjinparameters het, omdat hoër inlaatdruk die lugvloeitempo deur die enjin verhoog. Hoër lugmassavloei verminder verbrandingsgastemperatuur as gevolg van 'n hoër oortollige lugverhouding tydens verbranding. 'n Verdere gevolg van 'n hoër oortollige lugverhouding is dat minder roet gevorm word gedurende die eerste verbrandingsfase en meer roet en gedeeltelik verbrande koolwaterstofverbindings oksideer gedurende die finale verbrandingsfase. Dus, met 'n hoër inlaatdruk word Bosch rookemmissies verlaag. Geen wesenlike verandering in rookkonsentrasies word egter gesien met 'n verandering in inlaatlugtemperatuur nie, behalwe by baie lae inlaatdruk- en hoë inlaat lugtemperatuur-toetskondisies waar lae lug/brandstofverhoudings bestaan en 'n klein toename in lugmassavloei as gevolg van laer inlaat lugtempertuur'n groot invloed het. Stikstofmonoksied (NO) emissies is meer afhanklik van inlaat lugtemperatuur as inlaatdruk. Dit is bewys in die meervoudige regressiemodel. Die vlamsone- en die navlamsone- temperatuur speel 'n groot rol in NO vorming. Inlaat lugtemperatuur beïnvloed die temperatuur van die onstekingsmengsel en die daaropvolgende vlamsonetemperatuur. 'n Laer inlaat lugtemperatuur veroorsaak 'n langer onstekingsvertraging en verhoog die aanvanklike verbrandingstempo.

published_or_final_version / Urban Planning and Environmental Management / Doctoral / Doctor of Philosophy

Mice were exposed to diesel exhaust for 9 months prior to evaluation for benzo(a)pyrene disposition. On the last day of exposure the mice were instilled intratracheally with tritiated-benzo(a)pyrene ([3H]BP). The mice were sacrificed at intervals of 2, 24, and 168 hours. Disappearance of radioactivity from lungs and liver was rapid and essentially linear with time. In lungs, liver, and testes; [3H]BP metabolites were found mainly as conjugates, a form readily excretable. Clearance of the hydrocarbon from liver and testes in exposed mice was not markedly different from that in nonexposed mice. However, mice exposed to diesel exhaust had delayed [3H]BP clearance from lungs, possibly due to [3H]BP adsorption to diesel smoke particles.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Mark C. Zaretsky. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Seyed Hossein Mansouri. / Ph.D.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains x, 98 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 76-88).

Thesis (Ph. D.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 12, 2008) Includes bibliographical references.

M. Tech. Mechanical Engineering. / Biodiesel, produced from the transesterification of vegetable oils or animal fats with simple alcohol in the presence of a catalyst, is well positioned to replace petroleum-based diesel. Biodiesel is a non-toxic, biodegradable and renewable fuel. Despite its advantages, the chemical nature of biodiesel makes it more susceptible to oxidation compared to mineral diesel during long-term storage. The production of Croton Oil Methyl Ester (COME), Moringa Oil Methyl Ester (MOME) and Jatropha Oil Methyl Ester (JOME) was therefore carried out. Also, a determination of the fuel related properties and investigation of oxidation stability of the methyl esters produced without and with antioxidants and its blends with mineral diesel were conducted. The results showed that most of the measured fuel related properties of produced methyl esters fulfilled the minimum requirements of EN 14214 and ASTM 6751 biodiesel standards. However, COME and MOME did not meet EN 14214 oxidation stability standards (6 h) while JOME displayed very high oxidation stability (10.43 h) well within specified oxidation stability standards. Overall, the biodiesel derived from non-edible oils of African origin such as COME, MOME and JOME can be utilized as a partial substitute for mineral diesel. This study recommends that PY and PG antioxidants be used for safeguarding biodiesel fuel from the effects of autoxidation during storage.

Thesis (Ph.D.)--North Carolina State University. / Includes vita. Includes bibliographical references.