Comparison between the Nereis diversicolor and Nereis virens marine worms in the transformation of ingested hydrocarbons

A feeding experiment was conducted on the marine worm Nereis diversicolor to compare the fate of a hydrocarbon mixture during the gut passage in this species with the hydrocarbon breakdown process demonstrated for Nereis virens. Hydrocarbon dissolution/solubilization processes in the gut of N. diversicolor were found to have similar qualitative and quantitative importance in the hydrocarbon transformation as those observed in N. virens

Hydrogen-rich gas generator

A process and apparatus are described for producing hydrogen-rich product gases. A spray of liquid hydrocarbon is mixed with a stream of air in a startup procedure and the mixture is ignited for partial oxidation. The stream of air is then heated by the resulting combustion to reach a temperature such that a signal is produced. The signal triggers a two way valve which directs liquid hydrocarbon from a spraying mechanism to a vaporizing mechanism with which a vaporized hydrocarbon is formed. The vaporized hydrocarbon is subsequently mixed with the heated air in the combustion chamber where partial oxidation takes place and hydrogen-rich product gases are produced

In situ reflection electron energy loss spectroscopy measurements of low temperature surface cleaning for Si molecular beam epitaxy

In situ analysis of hydrocarbon desorption from hydrogen terminated Si(100) surfaces was performed in a silicon molecular beam epitaxy system, using reflection electron energy loss spectroscopy, in conjunction with conventional reflection high energy electron diffraction analysis. Measurements of C K edge core loss intensities demonstrate that this method is sufficiently sensitive to enable in situ analysis of hydrocarbon desorption at fractional monolayer coverages during low-temperature isothermal anneals. Hydrocarbon desorption was found to begin at 115 °C, and at 200 °C complete desorption occurred within 10 min. Hydrocarbon coverage was not measurably affected by operation of ionization gauge filaments during low temperature anneals, but was increased by transient outgassing of the sample holder, and its environs

High energy-density liquid rocket fuel performance

A fuel performance database of liquid hydrocarbons and aluminum-hydrocarbon fuels was compiled using engine parametrics from the Space Transportation Engine Program as a baseline. Propellant performance parameters are introduced. General hydrocarbon fuel performance trends are discussed with respect to hydrogen-to-carbon ratio and heat of formation. Aluminum-hydrocarbon fuel performance is discussed with respect to aluminum metal loading. Hydrocarbon and aluminum-hydrocarbon fuel performance is presented with respect to fuel density, specific impulse, and propellant density specific impulse

Characterization of the transverse relaxation rates in lipid bilayers

The 2H NMR transverse relaxation rates of a deuterated phospholipid bilayer reflect slow motions in the bilayer membrane. A study of dimyristoyl lecithin specifically deuterated at several positions of the hydrocarbon chains indicates that these motions are cooperative and are confined to the hydrocarbon chains of the lipid bilayer. However, lipid head group interactions do play an important role in modulating the properties of the cooperative fluctuations of the hydrocarbon chains (director fluctuations), as evidenced by the effects of various lipid additives on the 2H NMR transverse relaxation rates of the dimyristoyl lecithin bilayer

Film thickness measurements on five fluid formulations by the mercury squeeze film capacitance technique

The thinning characteristics of five fluids were studied by measuring film thickness as a function of time. The mercury squeeze film capacitance technique was used. All tests were performed at room temperature. The synthetic hydrocarbon plus a nematic liquid crystal, N-(p-methoxybenzylidene)-p-butylaniline, thinned according to a Newtonian model and retained its bulk viscosity. The synthetic hydrocarbon plus a phosphonate antiwear additive and the synthetic hydrocarbon plus n-hexadecanol produced residual thick films. The synthetic hydrocarbon base fluids and the synthetic hydrocarbon plus a paraffinic resin displayed viscosity increases during thinning, but no residual films were formed

Purely predictive method for density, compressibility, and expansivity for hydrocarbon mixtures and diesel and jet fuels up to high temperatures and pressures

This study presents a pseudo-component method using the Perturbed-Chain Statistical Associating Fluid Theory to predict density, isothermal compressibility, and the volumetric thermal expansion coefficient (expansivity) of hydrocarbon mixtures and diesel and jet fuels. The model is not fit to experimental density data but is predictive to high temperatures and pressures using only two calculated or measured mixture properties as inputs: the number averaged molecular weight and hydrogen to carbon ratio. Mixtures are treated as a single pseudo-component; therefore binary interaction parameters are not needed. Density is predicted up to 470 K and 3,500 bar for hydrocarbon mixtures and fuels with 1% average mean absolute percent deviation (MAPD). Isothermal compressibility is predicted with 4% average MAPD for hydrocarbon mixtures and 9% for fuels. The volumetric thermal expansion coefficient is predicted with 7% average MAPD for hydrocarbon mixtures and 13% for fuels

On the Insignificance of Photochemical Hydrocarbon Aerosols in the Atmospheres of Close-in Extrasolar Giant Planets

The close-in extrasolar giant planets (CEGPs) reside in irradiated environments much more intense than that of the giant planets in our solar system. The high UV irradiance strongly influences their photochemistry and the general current view believed that this high UV flux will greatly enhance photochemical production of hydrocarbon aerosols. In this letter, we investigate hydrocarbon aerosol formation in the atmospheres of CEGPs. We find that the abundances of hydrocarbons in the atmospheres of CEGPs are significantly less than that of Jupiter except for models in which the CH$_4$ abundance is unreasonably high (as high as CO) for the hot (effective temperatures $\gtrsim 1000$ K) atmospheres. Moreover, the hydrocarbons will be condensed out to form aerosols only when the temperature-pressure profiles of the species intersect with the saturation profiles--a case almost certainly not realized in the hot CEGPs atmospheres. Hence our models show that photochemical hydrocarbon aerosols are insignificant in the atmospheres of CEGPs. In contrast, Jupiter and Saturn have a much higher abundance of hydrocarbon aerosols in their atmospheres which are responsible for strong absorption shortward of 600 nm. Thus the insignificance of photochemical hydrocarbon aerosols in the atmospheres of CEGPs rules out one class of models with low albedos and featureless spectra shortward of 600 nm.Comment: ApJL accepte

Solubility behaviour, crystallisation kinetics and pour point : a comparison of linear alkane and triacyl glyceride solute/solvent mixtures

Mixtures of either a hydrocarbon wax in a hydrocarbon solvent or a long chain triacyl glyceride (TAG) in a TAG solvent show complex solubility boundary temperature hysteresis and precipitated crystal network formation leading to gelation. For these industrially-important systems, we show how the equilibrium solubility and its hysteresis, crystallisation kinetics and pour point temperature vary with solute concentration for representative examples of both hydrocarbon (n-tetracosane (C24) solute in n-heptane (C7) solvent) and TAG (tristearin (SSS) solute in tricaprylin (CCC) solvent) mixtures. The behaviour is modelled with good accuracy; thereby providing a useful aid to formulation and process optimisation