Low temperature combustion (LTC) is an appealing new method of combustion that promises low nitric oxides and soot emissions while maintaining or improving on engine performance. The three main points of this study were to develop and validate an engine model in GT-Power capable of implementing LTC, to study parametrically exhaust gas recirculation (EGR) and injection timing effects on performance and emissions, and to investigate methods to decrease pressure rise rates during LTC operation. The model was validated at nine different operating points, 3 speeds and 3 loads, while the parametric studies were conducted on 6 of the 9 operating points, 3 speeds and 2 loads. The model consists of sections that include: cylinders, ports, intake and exhaust manifolds, EGR system, and turbocharger. For this model, GT-Power calculates the combustion using a multi-zone, quasi-dimensional model and a knock-induced combustion model. The main difference between them is that the multi-zone model is directly injected while the knock model is port injected. A variety of sub models calculate the fluid flow and heat transfer. A parametric study varying the EGR and the injection timing to determine the optimal combination was conducted using the multi-zone model while a parametric study that just varies EGR is carried out using the knock model. The first parametric study showed that the optimal EGR and injection timing combination for the low loads occurred at high levels of EGR (60 percent) and advanced injection timings (30 to 40 crank angle degrees before top dead center). The optimal EGR and injection timing combination for the high loads occurred at low levels of EGR (30 percent to 40 percent) and retarded injection timings (7.5 to 5 crank angle degrees before top dead center). The knock model determined that the ideal EGR ratio for homogeneous charge compression ignition (HCCI) operation varied from 30 percent to 45 percent, depending on the operating condition. Three methods were investigated as possible ways to reduce pressure rise rates during LTC operation. The only feasible method was the multiple injection strategy which provided dramatically reduced pressure rise rates across all EGR levels and injection timings.

As global focus shifts towards the health and conservation of the planet, greater importance is placed upon the hazardous emissions of our fossil fuels, as well as their finite supply. These two areas remain intense topics of research in order to reduce green house gas emissions and increase the fuel efficiency of our vehicles. A particular solution to this problem is the diesel engine, with its inherently fuel-lean combustion, which gives rise to low CO2 production and higher efficiencies than its gasoline counterpart. Diesel engines, however, typically exhibit higher nitrogen oxides (NOx [NOx = NO NO2, where NO is nitric oxide and NO2 is nitrogen dioxide]) and soot. There exists the possibility to simultaneously reduce both emissions with the application of low temperature diesel combustion (LTC). While exhibiting great characteristics in simultaneous reductions in nitrogen oxides and soot, LTC faces challenges with higher carbon monoxide (CO) and hydrocarbon (HC) emissions, as well as penalties in fuel efficiency. The following study examines the characteristics of LTC which contribute to the differences in emissions and efficiency compared to typical conventional diesel combustion. More specifically, key engine parameters which are used to enable LTC, such as EGR and fuel pressure are swept through a full range to determine their effects on each combustion regime. Analysis will focus on comparing both combustion regimes to determine how exhaust gas recirculation (EGR) and fuel pressure relate to lowering NO and smoke concentrations, and how these relate to a penalty in fuel efficiency. This study finds that the application of LTC is able to realize a 99 percent reduction in NO while simultaneously reducing smoke by 17 percent compared to the conventional combustion counterpart. Through a sweep increasing EGR, LTC is able to defeat the typical soot – NO tradeoff; however, brake fuel conversion efficiency decreases 6.8 percent for LTC, while conventional combustion realizes a 4 percent increase in efficiency. The sweep of increasing fuel pressure confirms typical increases in NO and decreases in smoke for both LTC and conventional combustion; however, brake fuel conversion efficiency increases 2.3 percent for LTC and drops 4 percent for conventional combustion.

Automobile transportation consumes a significant amount of non-reusable energy and emits emissions as by-products of fuel consumption. There has been much progress in the development of vehicle engine technology and alternative fuels to reduce the adverse impact of highway transportation on the environment. However, the research regarding the reduction of the adverse impact through highway design is still in its infancy. Furthermore, highway design manuals/guidebooks do not provide any information on environmentally-friendly designs. The primary objective of this research was to provide the tools and guidelines for a quantitative environmental evaluation in highway design. This research provided the results regarding the quantitative environmental impacts, by means of fuel consumption and emissions, of various highway geometric design conditions on the vertical grades as well as for horizontal and vertical crest curves that could be included in the highway design process. The researcher generated second-by-second speed profiles using the speed prediction models and non-uniform acceleration/deceleration models, and extracted the fuel consumption and emissions rates based on vehicle specific powers and speeds using recently developed motor vehicle emission simulator (MOVES). The generated speed profiles were matched with the extracted rates and aggregated during a trip on the grades and curves. In addition, the researcher conducted the environmental evaluation including a benefit-cost analysis with actual highway geometric data based on the proposed method and processes. The results demonstrated that fuel consumption and emissions could be significantly changed according to highway design conditions on grades and curves. Throughout the analyses, this research provides the guidelines and tools for environmental evaluations related to selected design features as a part of the highway development process. The provided guidelines and tools can reduce the uncertainty associated with the engineering judgment for environmentally-conscious highway design. Finally, this research shows the efficacy of environmentally-friendly design for sustainable (i.e., social, economical, and environmental) transportation.

In recent years, the development and use of biofuels have received considerable attention due to the high demand for environmentally acceptable (green) fuels. Most of the recent studies have looked at the processes of converting vegetable oils into biodiesel. It is well known vegetable oil to biodiesel conversion involves many processes including transesterification, which makes biodiesel costly and time-consuming to produce. In this study, the effects of blending high-viscosity fresh and used corn oils with low-viscosity diesel and jet fuel mixed with butanol and ethanol were studied. Several corn oil-based blends were formulated and characterized to understand the effect of composition on viscosity, fuel stability and energy content. The formulated corn oil blends were combusted in a 30 kW modified combustion chamber to determine the corresponding NOx and CO emission levels, along with CO₂ levels. Used corn oil was made by simply heating fresh corn oil for a fixed period of time (about 44 hours), and was characterized by quantifying its total polar material (TPM), iodine value, free fatty acid content, and peroxide value. The combustion experiments were conducted at a constant heat output of 68,620 kJ/hr (19 kW), to observe and study the effects of equivalence ratio, swirl number, and fuel composition on emissions. Used corn oil blends exhibited better combustion performance than fresh corn oil blends, due in part to the higher unsaturation levels in fresh corn oil. NOx emissions for used corn oil increased with swirl number. Among all the blends, the one with the higher amount of diesel (lower amount of corn oil) showed higher NOx emissions. The blend with fresh corn oil showed decreasing NOx with increasing equivalence ratio at swirl number 1.4. All blends showed generally decreasing CO trends at both swirl numbers at very lean conditions. The diesel fuel component as well as the alcohols in the blends were also important in the production of pollutants. Compared to the diesel-based blends mixed with used corn oil, butanol, and ethanol, the jet fuel-based blends showed higher NOx levels and lower CO levels at both swirl numbers.

Hsuehshan tunnel which included two bore and three ventilation shaft systems is the longest (12.9 km) freeway tunnel in Taiwan. 56 species volatile organic compounds (VOCs) were sampled in two different locations each bore and three emitted shafts to determine the emission factors (EFs). Each sampling day has three sampling period: morning (8:00-10:00), Noon (12:00-14:00) and afternoon 16:00-18:00). C2 species were analyzed by GC/FID and C3 − C12 species were analyzed by GC/MS. The composition in southern bore was expressed by alkanes (36.69% − 39.20%), aromatics (34.14% − 36.33%), alkenes (20.27% − 21.95%), Alkynes (3.35% − 4.11%) and Naphthenes (1.06% − 1.35%). Northern bore had the similar profile. Ethylene (4.93 ¡Ó 2.21 mg/veh-km), Isopropane (4.85 ¡Ó 2.75 mg/veh-km), toluene (4.55 ¡Ó 1.31 mg/veh-km), m,p-xylene (2.98 ¡Ó 0.90 mg/veh-km) and propylene (2.70 ¡Ó 0.88 mg/veh-km) are the top five abundant VOCs in southern bore ; Isopropane (6.78 ¡Ó 3.33 mg/veh-km), ethylene (5.44 ¡Ó 2.63 mg/veh-km), toluene (5.32 ¡Ó 2.39 mg/veh-km), propylene (3.55 ¡Ó 1.67 mg/veh-km) and m,p-xylene (3.36 ¡Ó 1.45 mg/veh-km) are the top five abundant VOCs in northern bore. The EFs were smaller than other freeway tunnel investigated. Shaft emitted the partial mass of VOCs result in concentration gradient dropped off. The total VOCs EF of shafts during holidays was in the range of 72.24 mg/s − 180.60 mg/s higher than on weekdays in the range of 53.40 mg/s − 82.74 mg/s. The EF of shafts had effected by air-extracting apparatus, so standard deviations (S.D.) varied widely. Combining the EF of shaft with EF of tunnel we obtained the overall vehicle EF which was close to other freeway tunnel results. The proportion of Ozone formation potential (OFP) in both bore were alkenes (47.5% − 48.5%), aromatics (40.2% − 42.3%) and alkanes (9.8% − 10.1%). Note that sum of alkenes and aromatics exceeded 90%.

This research investigate and analysis 77 kinds of volatile organic compounds (VOCs) in the sewage system of a southern urban area (A, B, C, D, E and F). The 77 kinds of VOCs will be divided into BTEX, chlorine-containing hydrocarbons and non-chlorine-containing hydrocarbons, and to estimate the emission of 27 kinds of hazardous air pollutants (HAPs). Cancer risk within 12 kinds of HAPs will also be part of the investigation by using Risk Assessment. In terms of consistency, except A1, D5 and E, VOCs are required mainly of non-chlorine-containing hydrocarbons at other areas, and main contribution species are ethylene, acetylene and ethane. There are 55.05 % of BTEX (1298.2 £gg/m3) and 35.51 % of non-chlorine-containing hydrocarbons (837.6 £gg/m3) in A1, but the main contribution are toluene, m-xylene and p-xylene. In D5, there is 76.39 % of BTEX (3744.7 £gg/m3) and the main contribution are m-xylene, p-xylene and toluene. In E, there is 80.02 % of chlorine-containing hydrocarbons (4807.1 £gg/m3) and the main contribution are chloromethane and toluene. Results show that the most emissions of total HAPs is D5 (12195.3 mg/hr), followed by B2 (4602.9 mg/hr), E (2659.4 mg/hr), A4 (2043.7 mg/hr) and A1 (1526.2 mg/hr). BTEX represent the largest proportion of the emissions of total HAPs in D5, A4 and A1. Chloroethene represents the largest proportion of the emissions of total HAPs in B2, followed by trichloroethene and tetrachloroethene. Chloromethane represents the largest proportion of the emissions of total HAPs in E. The most cumulative cancer risk in the sewage space is B2, followed by C2 and A3. The main contribution of the average cancer risk (not include B2) in a southern urban area are 1,1,2-trichloroethane, 1,2-dichloroethane and 1,4-dichlorobenzene.

Current emission prediction models in the conceptual design phase are based on historical data and empirical correlations. Two main reasons contributing to the current state of emission models are complexity of the phenomena involved in the combustor and relatively low priority of having a more detailed emissions model at the conceptual design phase. However, global environmental concerns and aviation industry growth highlight the importance of improving the current emissions prediction approaches. There is a need to have an emission prediction model in the conceptual design phase to reduce the prediction uncertainties and perform parametric studies for different combustor types and operating conditions. The research objective of this thesis is to develop a methodology to have an initial estimate of gas turbines' emissions, capture their trends and bring more information forward to the conceptual design phase regarding the emission levels. This methodology is based on initial sizing of the combustor and determining its flow-fractions at each section using a 1D flow analysis. A network of elementary chemical reactors is considered and its elements are sized from the results of the 1D flow analysis to determine the level of emissions at the design and operating conditions. Additional phenomena that have significant effects on the prediction of emissions are also considered which are: 1) droplet evaporation and diffusion burning, and 2) fuel-air mixture non-uniformity. A simplified transient model is developed to determine the evaporation rate for a given droplet size distribution and to obtain the amount of vaporized fuel before they ignite. A probabilistic unmixedness model is also employed to consider the range of equivalence ratio distribution for the fraction of the fuel that is vaporized and mixed with air. An emission model is created for the single annular combustor (SAC) configuration and applied to two combustors to test the prediction and parametric capabilities of the model. Both uncertainty and sensitivity analyses are performed to assess the capability of the model to reduce the prediction uncertainty of the model compared to the simpler models without considering the droplet evaporation and mixture non-uniformity. The versatility of the model is tested by creating an emission model for a Rich-Quench-Lean (RQL) combustor, and the results are compared to limited actual data. In general, the approach shows a good performance predicting the NOx emission level compared to CO emission level and capturing their trends. Especially in the RQL combustor case, a more detailed model is required to improve the prediction of the CO emission level.

Die Energieerzeugung aus fossilen Brennstoffen trägt weltweit erheblich zum Treibhauseffekt bei. So entfielen 2005 24 % der gesamten CO2-Emissionen in der Europäischen Union auf die Stromerzeugung aus Kohle [1]. Recherchen im Rahmen eines Forschungsvorhabens an der Professur für Betriebliche Umweltökonomie der TU Dresden ergaben, dass öffentliche Gebietskörperschaften einen Anteil von ca. 7,8 % am Stromverbrauch in Deutschland haben. Bisher berücksichtigen jedoch nur wenige Kommunen die CO2-Emissionen als Entscheidungskriterium bei der Ausschreibung von Strom. Damit wird deutlich, welches Potenzial in der Ausschreibung von Strom liegen kann. Hierbei stellt sich allerdings nicht nur die Frage, welche Herausforderungen öffentliche Ausschreibungen mit sich bringen, sondern auch wie diese Möglichkeiten den Markt aus der Sicht des Nachfragers eingrenzen, d. h. ob überhaupt ein entsprechendes Angebot am Markt verfügbar ist. / Energy supplies on the basis of fossil fuels contribute significantly to the global greenhouse effect. In 2005, for example, 24 % of the total CO2 emissions in the EU were attributable to coal-fired power generation. The work of a research project at TU Dresden revealed that public administrative bodies account for approx. 7.8 % of electricity consumption in Germany. To date, however, only few communities have made CO2 emissions a decision criterion in their electricity procurement. It is thus clear, just how much potential lies in the procurement process for electricity. At the same time, however, consideration must be given not only to the challenges arising from the appraisal of public procurement, but also to how these options limit the market scope from the point of view of the community, i.e. whether corresponding offers are actually available on the market.

Thesis (M. Communication Pathology)--University of Pretoria, 2008. / Summary in English and Afrikaans. Includes bibliographical references.

The purpose of this report was to compare Lilluns egg production with other Swedish egg producers based on the flow of nutrients (nitrogen, phosphorus and potassium) in the egg production systems. The main focus in the report was the utilization rate of the forage and the excess of nutrients per kg egg. Additionally, the purpose was to identify the environmental impact from Lilluns egg production and compare the results with other egg producers. The inflow of nutrients associated with forage and poultry was compared with the nutrients that were exported from the production. All of the egg producers in this study had an excess of nutrients. The utilization rate of the forage for Lilluns egg was 47 %, the other egg producers in this study had an utilization rate between 45-50 %. The results showed that Lilluns egg had an excess of nitrogen of 0,04 kg/kg eggs. Lilluns egg also had an excess of phosphorus and potassium. The excess of phosphorus was 0,01 kg/kg eggs and 0,013 kg/kg eggs for potassium. The results showed that all the egg producers in this study had an excess of all the nutrients. The conclusion is that the egg production systems in this study have a similar utilization rate and the excess of nutrients per kg egg was also similar for all the egg producers.