On Stability Testing Analysis in Phase Behavior Calculations

Abstract

Stability testing analysis has become, in recent times, an area of major interest in phase equilibrium calculations. With particular concern to reservoir fluid phase behavior modeling, it has become the most important factor in developing robust algorithms and ensuring efficient calculations. We discuss the origin and systematic development of stability testing analysis as a necessary preliminary step in isothermal flash calculations. Its application to multicomponent multiphase reservoir fluids and extension prospects is also highlighted.     

A MATHEMATICAL MODEL FOR MILD HYDROCRACKING:KINETICS AND PRODUCT YIELDS FROM A CRUDE OIL BLEND IN LIGHT GAS OIL OVER HYDROTREATING CATALYST.

Abstract

Mild hydrocracking of 30% crude oil (Indian Crude oil.North Gujarat base)solution in light gas oil is carried out over a commercial hydrotreating catalyst at a temperature range of 300–450°c and pressure of 6. 8–20.OMpa in laboratory reactor. About 30 to 60% of the long residue (365° c+ cut) in the solution is converted to light distillates.

A mathematical model has been developed to predict the yields of products.     

STRUCTURAL CHARACTERIZATION OF SOLID n-PARAFFIN COMPONENTS DERIVED FROM MUKTA CRUDE OIL

ABSTRACT

The total solid paraffins (boiling 270°C+) separated from Mukta crude by urea adduction and its narrow fractions were analysed for their structural composition by proton NMR, infrared spectroscopy and gas chromatography. It has been observed that CH2/CH3 ratio in these samples varies from 7·9 to 13·8 while their average carbon number ranges from 17 to 29·6. The CH₂/CH₃ ratio and chain length of paraffins increases with increase in boiling range of the fractions.     

Zur Zellwandstruktur von 1600 Jahre altem, wassergesättigtem Eichenholz

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th century A.D.) was investigated by transmission electron microscopy. The studies on the cell wall fine structure revealed that in most cells the middle lamella and the innermost secondary wall layer (S3) remained structurally unaltered. On the other hand, the secondary wall layers S1 and S2 became heavily degraded. The characteristic degradation pattern indicates the involvement of bacteria.

     

Phytate Hydrolysis by Phytase in Cereals; Effects on In Vitro Estimation of Iron Availability

Phytate (inositol hexaphosphate) hydrolysis by endogenous and exogenous phytases was studied for their effect on increasing iron availability in cereals. Wheat bran and whole meal flours of rye and oats were soaked at optimal conditions for phytase activity (55°C, pH 5) for different time intervals. Phytate and its degradation products were determined by HPLC and related to iron solubility under simulated physiological conditions. Small amounts of phytate (< lμmol/g) had a strong negative effect on iron solubility. When inositol hexa- and pentaphosphates of wheat bran and rye flour were completely hydrolyzed by activating endogenous phytase, iron solubility under simulated physiological conditions increased from 3 to 53% (wheat) and 5 to 21% (rye). Addition of wheat phytase to uncooked oatmeal increased iron solubility from 4 to 11 and in precooked to 18%, while endogenous phytase of uncooked oatmeal had less effect on phytate digestion and iron solubility.     

Processing Ingredients Affecting Oxidative and Textural Stability of Restructured Beef Roasts

Restructured beef roasts containing 0.3% sodium tripolyphosphate (STP) and 1% soy protein isolate (SPI); or STP only; or SPI only; or no STP or SPI were cooked at 70 or 100°C to an internal temperature of 65°C, then stored at 4°C for 0 and 3 days. In control roasts, the higher cooking temperature resulted in higher (p ≤ 0.05) TBA values. STP and SPI inhibited oxidation but the effect was not detected sensorially. Significant interactions (p ≤ 0.05) indicated that STP was more effective at higher cooking temperatures and SPI at lower temperatures. Total moisture of the cooked product was significantly greater with STP but no differences in juiciness and tenderness were detected sensorially.     

Photothermovoltaic effect in a pSi-n(Si2)1 − x − y (ZnSe) x (GaP) y (0 ≤ x ≤ 0.88, 0 ≤ y ≤ 0.09) structure

The results of creating a variband epitaxial (Si₂)_{1 ? x ? y} (ZnSe) _x (GaP) _y layer and observing the photothermovoltaic effect in a pSi-n(Si₂)_{1 ? x ? y} (ZnSe) _x (GaP) _y (0 ≤ x ≤ 0.88, 0 ≤ y ≤ 0.09) heterostructure heated by concentrated solar radiation are detailed. It is shown that the photothermal and thermal voltages in the heterostructure equal 5.8 and 1.2 mV at a temperature of 80°C. The observed relatively high photothermal voltage value is attributed to the possible extrinsic thermophotoelectric effect in the layer of diluted solid solution adjacent to the p-n junction.     

Review and Comparison of Nanofluid Thermal Conductivity and Heat Transfer Enhancements

This study provides a detailed literature review and an assessment of results of the research and development work forming the current status of nanofluid technology for heat transfer applications. Nanofluid technology is a relatively new field, and as such, the supporting studies are not extensive. Specifically, experimental results were reviewed in this study regarding the enhancement of the thermal conductivity and convective heat transfer of nanofluids relative to conventional heat transfer fluids, and assessments were made as to the state-of-the-art of verified parametric trends and magnitudes. Pertinent parameters of particle volume concentration, particle material, particle size, particle shape, base fluid material, temperature, additive, and acidity were considered individually, and experimental results from multiple research groups were used together when assessing results. To this end, published research results from many studies were recast using a common parameter to facilitate comparisons of data among research groups and to identify thermal property and heat transfer trends. The current state of knowledge is presented as well as areas where the data are presently inconclusive or conflicting. Heat transfer enhancement for available nanofluids is shown to be in the 15–40% range, with a few situations resulting in orders of magnitude enhancement.     

Multiscale Nonlocal Thermo-Elastic Analysis of Graphene Nanoribbons

This paper investigates the effect of interfacial thermal characteristics and nonlocal effects on the overall effective thermal property of graphene nanoribbons embedded in low-density polyethylene matrix. It is widely known that apart from the thermal conductivity, the effect of interfacial thermal resistance is the most important factor that determines the thermal efficiency of nanostructures. In this work, we develop nonlocal thermo-elastic properties coupled with a multiscale strategy by means of properties derived from atomistic simulations. Atomistic based thermal properties of graphene nanoribbons are estimated from molecular dynamics (MD) simulations and the effect of inter-tubular spacing on the interfacial thermal characteristics are also studied. The paper also discusses the effect of the nonlocal parameter on the thermal conduction of the composite system using the developed nonlocal thermo-elastic model.     

Fungal growth inhibition by wood extracts from<Emphasis Type="Italic"> Juniperus foetidissima</Emphasis> and<Emphasis Type="Italic"> J. oxycedrus</Emphasis>

SubjectSap- and heartwood extracts obtained by successive extractions with cyclohexane, chloroform, ethanol and hot water from J. foetidissima and J. oxycedrus were tested for their antifungal activity by using the agar plate method. Generally, the extractive substances of heartwoods soluble in nonpolar or slightly polar solvents show higher activities, whereas the extract fractions with higher polarity also seem to possess notable inhibition in case of sapwoods.