Alternative Fuels

Bechtold, Richard L.

doi:10.4271/t-100

Cited by 19 publications

(10 citation statements)

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“…Steidel & Sargent 1992;Nestor et al 2005;Prochter et al 2006), where the Mg II λλ 2796, 2803 doublet features are redshifted into the optical spectral window at wavelength λ > 3800 Å. Few absorbers are known at lower redshifts (Jannuzi et al 1998;Bechtold et al 2002). At the same time, wide-field surveys such as the Sloan Digital Sky Survey (SDSS; York et al 2000) have yielded detailed maps of the large-scale galaxy distribution over 1/4 of the sky.…”

Section: Experiments Designmentioning

confidence: 99%

AN EMPIRICAL CHARACTERIZATION OF EXTENDED COOL GAS AROUND GALAXIES USING Mg II ABSORPTION FEATURES

Chen

Helsby

Gauthier

et al. 2010

ApJ

287

488

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We report results from a survey of Mg II absorbers in the spectra of background QSOs that are within close angular distances to a foreground galaxy at z < 0.5, using the Magellan Echellette Spectrograph. We have established a spectroscopic sample of 94 galaxies at a median redshift of z = 0.24 in fields around 70 distant background QSOs (z QSO > 0.6), 71 of which are in an 'isolated' environment with no known companions and located at ρ 120 h −1 kpc from the line of sight of a background QSO. The rest-frame absolute B-band magnitudes span a range from M B − 5 log h = −16.4 to M B − 5 log h = −21.4 and rest-frame B AB − R AB colors range from B AB − R AB ≈ 0 to B AB − R AB ≈ 1.5. Of these 'isolated' galaxies, we find that 47 have corresponding Mg II absorbers in the spectra of background QSOs and rest-frame absorption equivalent width W r (2796) = 0.1 − 2.34 Å, and 24 do not give rise to Mg II absorption to sensitive upper limits. Our analysis shows that (1) W r (2796) declines with increasing distance from 'isolated' galaxies but shows no clear trend in 'group' environments;(2) more luminous galaxies possess more extended Mg II absorbing halos with the gaseous radius scaled by B-band luminosity according to R gas = 75 × (L B /L B * ) (0.35±0.03) h −1 kpc; (3) there is little dependence between the observed absorber strength and galaxy intrinsic colors; and (4) within R gas , we find a mean covering fraction of κ 0.3 ≈ 70% for absorbers of W r (2796) ≥ 0.3 Å and κ 0.1 ≈ 80% for absorbers of W r (2796) ≥ 0.1 Å. The results confirm that extended Mg II absorbing halos are a common and generic feature around ordinary galaxies and that the gaseous radius is a fixed fraction of the dark matter halo radius. The lack of correlation between W r (2796) strength and galaxy colors suggests a lack of physical connection between the origin of extended Mg II halos and recent star formation history of the galaxies. Finally, we discuss the total gas mass in galactic halos as traced by Mg II absorbers. We also compare our results with previous studies. Subject headings: cosmology: observations-intergalactic medium-quasars: absorption lines 1 This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

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Section: Experiments Designmentioning

confidence: 99%

AN EMPIRICAL CHARACTERIZATION OF EXTENDED COOL GAS AROUND GALAXIES USING Mg II ABSORPTION FEATURES

Chen

Helsby

Gauthier

et al. 2010

ApJ

287

488

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“…This injection advance in case of biodiesel is attributed to its higher density resulting in faster travel of acoustic pressure waves [38]. Further, in the case of the rotary injection pump used in the set-up, the timings for the end of injection remain fixed and hence, to accommodate an additional quantity of biodiesel (owing to lower heating value) required to maintain the power level obtained in case of diesel fuel, the start of injection *Estimated from fatty acid composition following reference [34]; { taken from reference [35]; { taken from reference [36].…”

Section: Fuel Injectionmentioning

confidence: 99%

Experimental investigations on combustion, performance, and emissions characteristics of a neat biodiesel-fuelled, turbocharged, direct injection diesel engine

Anand

Sharma

Mehta

2010

Proceedings of the Institution of Mechanical Engineers, Part D:

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The concerns about clean environment, high oil prices, and stringent emission norms are the driving forces for the research on alternative fuels. Extensive investigations have been carried out in recent years on replacing diesel fuel by vegetable-oil-derived biodiesel fuel in compression ignition engines, mainly owing to its renewable source, reduced emissions, and direct usage without any engine modifications. The experimental work reported here has been carried out on a turbocharged, direct injection, multi-cylinder truck diesel engine using diesel fuel and neat karanja-oil-derived biodiesel under varying speed and load conditions. The results of the experimental investigation indicate that a maximum of 2.3Â°CA (crank angle) advance in dynamic fuel injection timing is observed with biodiesel compared with the diesel fuel. The ignition delay is lower for biodiesel compared with diesel fuel at all engine speeds. The peak cylinder pressure is higher at most of the operating conditions and the maximum rate of pressure rise is lower at low speeds and higher at high speeds for biodiesel compared with diesel fuel. In general an earlier start of combustion and lower combustion duration are observed for biodiesel relative to diesel fuel. The maximum thermal efficiency occurring at the maximum torque speed of 1400r/min is observed to be 40.7 per cent and 40.5 per cent for diesel and neat biodiesel respectively. A significant reduction in unburnt hydrocarbon and smoke emissions, comparable carbon monoxide emissions, and higher nitric oxide emissions are observed with biodiesel compared with diesel fuel operation. In general, an improvement in combustion characteristics and exhaust emissions, except nitric oxide, are observed for biodiesel compared with diesel fuel, with a slight penalty in brake thermal efficiency.

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“…On a mass basis, neat biodiesel has approximately 13% less energy than typical diesel fuel. This energy loss is caused by the oxygen contained in biodiesel approximately 11-15% of molecular weight and lower heating value (Bechtold, 2002).…”

Section: Introductionmentioning

confidence: 99%

Effect of the Temperature Variation on Properties of Biodiesel and Biodiesel-Ethanol Blends Fuels

Park

Yoon

Suh

et al. 2008

Oil & Gas Science and Technology - Rev. IFP

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Effet de la variation de la température sur les propriétés de carburants biodiesel et de mélanges biodiesel-éthanol -Cette étude a pour objectif de déterminer les effets de variations de température et de proportion d'éthanol dans un mélange biodiesel-éthanol sur les propriétés du carburant obtenu. L'ajout de l'éthanol à du biodiesel permet d'éviter l'inconvénient du démarrage à froid connu dans le cas du biodiesel. De plus, les variations de température influent sur le comportement du spray et les caractéristiques de la combustion et des émissions dans la chambre de combustion. La viscosité cinématique et la densité ont été obtenues respectivement par la mesure de la viscosité dynamique et de la gravité spécifique. Dans cette étude, on a pu observer que la gravité spécifique et la densité ont diminué linéairement lorsque la température et le taux d'éthanol dans le mélange ont augmenté. Une équation empirique a pu être obtenue à partir des valeurs mesurées ; c'est une fonction du second ordre du taux de mélange et du premier ordre de la température du mélange. Par ailleurs, les viscosités dynamiques et cinématiques ont diminué exponentiellement avec l'augmentation de la température. Basée sur ces mesures de viscosités, l'équation empirique, qui est fonction de la température, peut être étendue à chaque taux d'éthanol dans le mélange.

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Alternative Fuels

Cited by 19 publications

References 0 publications

AN EMPIRICAL CHARACTERIZATION OF EXTENDED COOL GAS AROUND GALAXIES USING Mg II ABSORPTION FEATURES

AN EMPIRICAL CHARACTERIZATION OF EXTENDED COOL GAS AROUND GALAXIES USING Mg II ABSORPTION FEATURES

Experimental investigations on combustion, performance, and emissions characteristics of a neat biodiesel-fuelled, turbocharged, direct injection diesel engine

Effect of the Temperature Variation on Properties of Biodiesel and Biodiesel-Ethanol Blends Fuels

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