The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Rolf D Reitz - One of the best experts on this subject based on the ideXlab platform.
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understanding the role of soot oxidation in gasoline combustion a numerical study on the effects of oxygen enrichment on particulate mass and number emissions in a spark ignition engine
Energy Conversion and Management, 2019Co-Authors: Elia Distaso, Riccardo Amirante, Paolo Tamburrano, Rolf D ReitzAbstract:Abstract The production of increasingly clean engines has become imperative. More stringent regulations for internal combustion engines are constantly proposed, and recent number-based regulations have become a new challenge, since historically only a mass-based regulation needed to be met. It is known that soot particles detectable at the exhaust of an engine are the results of the competition between the formation of soot precursor species and their oxidation. However, the attention is mainly focused on inhibiting soot precursors formation, and much less research is dedicated at elucidating the benefits achievable from enhancing soot oxidation rates. Soot oxidation can be enhanced by increasing the in-cylinder oxygen content. Oxygenated fuels, which are often added to gasoline in order to achieve more efficient combustion, can represent a possible way in the pursuit of this goal. However, chemical mechanisms are still uncertain for practical fuels, and ambiguous results can be produced when the effect of oxygenated fuels on gasoline engine combustion and soot emissions is considered. In the present study, 3-D Computational Fluid Dynamics simulations were performed and the numerical results were compared with existing experimental data, in which load increases were achieved by pure oxygen addition within the intake manifold of a single-cylinder Spark-Ignition (SI) engine. Studying the effects that an addition of 5% and 10% by volume (with respect to air) of additional oxygen produces on the combustion process, allowed to provide basic additional information on soot formation and oxidation, avoiding the uncertainties associated with chemistry models. A semi-detailed soot model and a chemical kinetic model, including Poly-Aromatic Hydrocarbon formation, were coupled with the G-equation flame propagation model for the SI engine simulations and for predicting soot mass and particulate number density. Improvements in the modeling of gasoline premixed combustion were achieved, as well. Specifically, different approaches in the evaluation of the laminar flame speed of gasoline (which is a key factor for obtaining reliable SI engine simulations) were critically compared and analyzed. The numerical results showed aspects that were not possible to appreciate by only referring to the experimental results on which this work was based. It was possible to observe that the higher soot concentrations were located in regions characterized by lower temperatures and lower OH concentrations. Oxygen addition favored a faster burning velocity and produced higher in-cylinder temperatures. However, the production rates of both OH radicals and soot precursor species resulted enhanced. The analysis of these concurrent phenomena allowed to explain why in the experiments the soot mass per kg of fuel was lower for the oxygenated combustion cases.
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development of a reduced tri propylene glycol monomethyl ether n hexadecane poly aromatic Hydrocarbon mechanism and its application for soot prediction
International Journal of Engine Research, 2016Co-Authors: Seunghyun Park, Rolf D Reitz, William J Pitz, Eric KurtzAbstract:A reduced chemical kinetic mechanism for tri-propylene glycol monomethyl ether has been developed and applied to computational fluid dynamics calculations for predicting combustion and soot formati...
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development of an n heptane n butanol pah mechanism and its application for combustion and soot prediction
Combustion and Flame, 2013Co-Authors: Rolf D Reitz, Hu Wang, Mingfa Yao, Binbin Yang, Qi Jiao, Lu QiuAbstract:A reduced chemical reaction mechanism was developed for modeling the combustion process and soot emissions for both non-oxygenated and oxygenated Hydrocarbon fuels. A detailed Poly-Aromatic Hydrocarbon (PAH) mechanism was reduced and embedded into a reduced n-heptane mechanism for describing the formation of PAH up to four rings (A4) and for soot prediction. A reduced n-butanol mechanism was combined with the n-heptane-PAH mechanism to investigate of effects of oxygenated n-butanol fuels on combustion and soot emissions. The final mechanism consists of 76 species and 349 reactions. The mechanism was validated with experiments in shock tubes, constant volume chambers and test-bed engine data. New experiments were also conducted and reported in current investigation and have been used to validate the proposed mechanism. The effects of oxygenated additives on combustion and soot emissions under diesel-like conditions were also investigated. The results show that the present simulations give reliable predictions of combustion and soot emissions. The results also agree with the general soot formation processes near the lift-off length in mixing controlled diesel fuel jets, and the present mechanism can be used to predict the combustion and soot emissions of diesel, n-heptane and n-butanol fuels in 3D CFD simulations.
Bo Ugwuishiwu - One of the best experts on this subject based on the ideXlab platform.
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Use of poultry droppings for remediation of crude-oil-polluted soils: Effects of application rate on total and Poly-Aromatic Hydrocarbon concentrations
International Biodeterioration & Biodegradation, 2014Co-Authors: G.i. Ezenne, Oji Achuka Nwoke, D.e. Ezikpe, S. E. Obalum, Bo UgwuishiwuAbstract:Abstract The aim of this research was to determine the role poultry droppings (PD) play in the process of reducing the concentrations of total petroleum Hydrocarbon (TPH) and Poly-Aromatic Hydrocarbon (PAH) in crude-oil-contaminated soils, and to check the effects of PD application rate on the bioremediation of such soils. This bioremediation trial was done ex-situ and the concentrations of TPH and PAH were used as an indicator of soil productivity restoration. The PD serving as amendment was applied to the crude-oil-contaminated soils collected from three sites in southern Nigeria at the rate of 0% (control), 5%, 10%, and 25% per dry mass of contaminated soil. Soil samples were evaluated for pH, TPH, and PAH after 6 wk. The results showed that the application rate of PD had significant reductive effects on the concentrations of TPH and PAH in the contaminated soils (P ≤ 0.05 and ≤0.01, respectively). There was a general increase in the mean percentage reduction in the concentrations of both TPH and PAH with increasing rate of PD application for all the three soils, with R2 values of 0.91 for TPH and 0.82 for PAH. The range of R2 for the regression between TPH/PAH concentration and PD rate across the three soils was narrower for TPH (0.89–0.94) than for PAH (0.69–0.94), suggesting a greater influence of the age of the crude oil contaminant in the soils on the bioavailability of the PAH. There were also linear correlations between the final soil pH and percentage reduction in the concentrations of both TPH (r = 0.53) and PAH (r = 0.48). Based on these relationships, a further increase of the PD above 25% may likely increase the soil pH to above tolerable limits for survival of plants and microorganisms.
Hu Wang - One of the best experts on this subject based on the ideXlab platform.
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development of an n heptane n butanol pah mechanism and its application for combustion and soot prediction
Combustion and Flame, 2013Co-Authors: Rolf D Reitz, Hu Wang, Mingfa Yao, Binbin Yang, Qi Jiao, Lu QiuAbstract:A reduced chemical reaction mechanism was developed for modeling the combustion process and soot emissions for both non-oxygenated and oxygenated Hydrocarbon fuels. A detailed Poly-Aromatic Hydrocarbon (PAH) mechanism was reduced and embedded into a reduced n-heptane mechanism for describing the formation of PAH up to four rings (A4) and for soot prediction. A reduced n-butanol mechanism was combined with the n-heptane-PAH mechanism to investigate of effects of oxygenated n-butanol fuels on combustion and soot emissions. The final mechanism consists of 76 species and 349 reactions. The mechanism was validated with experiments in shock tubes, constant volume chambers and test-bed engine data. New experiments were also conducted and reported in current investigation and have been used to validate the proposed mechanism. The effects of oxygenated additives on combustion and soot emissions under diesel-like conditions were also investigated. The results show that the present simulations give reliable predictions of combustion and soot emissions. The results also agree with the general soot formation processes near the lift-off length in mixing controlled diesel fuel jets, and the present mechanism can be used to predict the combustion and soot emissions of diesel, n-heptane and n-butanol fuels in 3D CFD simulations.
Marco Langbroek - One of the best experts on this subject based on the ideXlab platform.
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the cm carbonaceous chondrite regolith diepenveen
Meteoritics & Planetary Science, 2019Co-Authors: Marco Langbroek, Peter Jenniskens, Leo M Kriegsman, Henk Nieuwenhuis, Niek De Kort, Jacob Kuiper, Wim Van WestrenenAbstract:A carbonaceous chondrite was recovered immediately after the fall near the village of Diepenveen in the Netherlands on October 27, 1873, but came to light only in 2012. Analysis of sodium and Poly-Aromatic Hydrocarbon content suggests little contamination from handling. Diepenveen is a regolith breccia with an overall petrology consistent with a CM classification. Unlike most other CM chondrites, the bulk oxygen isotopes are extremely 16O rich, apparently dominated by the signature of anhydrous minerals, distributed on a steep slope pointing to the domain of intrinsic CM water. A small subset plots closer to the normal CM regime, on a parallel line 2 ‰ lower in δ17O. Different lithologies in Diepenveen experienced varying levels of aqueous alteration processing, being less aqueously altered at places rather than more heated. The presence of an agglutinate grain and the properties of methanol-soluble organic compounds point to active impact processing of some of the clasts. Diepenveen belongs to a CM clan with ~5 Ma CRE age, longer than most other CM chondrites, and has a relatively young K-Ar resetting age of ~1.5 Ga. As a CM chondrite, Diepenveen may be representative of samples soon to be returned from the surface of asteroid (162173) Ryugu by the Hayabusa2 spacecraft.
Praveen Sharma - One of the best experts on this subject based on the ideXlab platform.
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Application of Biochar as an Adsorbent and Its Significance on Berseem (Trifolium alexandrinum) Growth Parameters in Farm Soil Contaminated with PAH
Journal of Soil Science and Plant Nutrition, 2020Co-Authors: Varinder Kaur, Praveen SharmaAbstract:Soil properties can be significantly influenced by the addition of biochar and are known to enhance plant productivity and soil quality. Berseem acts as a good phytoaccumulator. The main aim of this study was to evaluate the effect of different concentrations of biochar on plant height, biomass, and chlorophyll content and on PAHs adsorption capacity at different time intervals. Sixteen treatment combinations were designed in three replicates for a total 144 pots. A soil/biochar ( w /w) mixture and Poly-Aromatic Hydrocarbon (PAH) content (50 mg kg^−1 naphthalene and 100 mg kg^−1 phenanthrene) of suitable ratio for each application was used for filling different pots, having dimensions of 19.6 cm diameter × 20.6 cm height. Various qualitative and quantitative methods were followed for further analysis of soil, plant, and biochar samples. Maximum plant height and plant biomass were observed at 5% and 10% biochar level in the soil as compared to control. Total available nutrients increased with biochar application rate. Increase in biochar concentration resulted in increased PAH adsorption capacity, thereby making it less available to cause the negative effect on plant growth parameters. Bio-concentration factor significantly decreased with increased biochar concentration in soil, i.e., from 92.5 to 5.31 in phenanthrene-contaminated soil and from 17.4 to 1.36 in mixed contaminated soil as compared to control. These results significantly prove that biochar enhanced the PAHs adsorption capacity as well as removal efficiency and crop yield. This study also shows the effectiveness of biochar on contaminant remediation with the help of Trifolium alexandrinum.
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Role of Prosopis juliflora biochar in Poly-Aromatic Hydrocarbon remediation using Trifolium alexandrinum L.
SN Applied Sciences, 2019Co-Authors: Varinder Kaur, Praveen SharmaAbstract:Biochar possesses a number of characteristics that make it suitable for remediation of organic and inorganic pollutants from soil. Biochar acts as a suitable amendment to the soil as it increases the surface negative charge, nutrient retention capacity, high adsorption affinity, porosity, resistance to degradation and a high internal surface area. The present research is based on pot experiment, from October 2015 to April 2016. A probe sonicator extraction procedure was used for the determination of naphthalene and phenanthrene in dried soil and plant samples using gas-chromatography coupled with flame ionization detector. Fortification was carried out by spiking the 50 mg/kg naphthalene and 100 mg/kg phenanthrene in soil. The extraction efficiency observed for phenanthrene was 74.62% and 66.59% for naphthalene with relative standard deviation in the range of 0.39 to 0.26, respectively. Naphthalene was not detected in soil and plant samples. BCF value significantly decreases with increasing the biochar concentration in soil as compared to control (non-biochar-amended soil). BCF level decreased significantly ( P ≤ 0.05) from 123.1 to 4.46 in phenanthrene-contaminated soil and 19.3–1.32 in mixed contaminated soil with time period. The maximum phenanthrene removal efficiency is observed to be 10% in biochar-amended soil as compared to other treatments (10% > 5% > 1% > control). Biochar significantly helps to increase plant height, dry biomass and total available nutrients. Above results showed that biochar derived from Prosopis juliflora effectively enhanced the PAHs surface adsorption capacity, removal efficiency and plant growth parameters. This study shows the effectiveness of biochar on contaminant remediation with the help of Trifolium alexandrinum.