BOUNDARY ELEMENT ANALYSIS OF GREEN AND LINDSAY THEORY UNDER THERMAL AND MECHANICAL SHOCK IN A FINITE DOMAIN

A boundary element formulation based on the Laplace transform method is developed for transient coupled thermoelasticity problems with relaxation times in a two-dimensional finite domain. The dynamic thermoelastic model of Green and Lindsay is selected for the present study. The Laplace transform method is applied to the time domain, and the resulting equations in the transformed field are discretized using the boundary element method. The nodal dimensionless temperature and displacements in the transformed domain are inverted to obtain the actual physical quantities using the numerical inversion of the Laplace transform method. This work considers the Green and Lindsay theory of thermoelasticity with the thermal and mechanical loading in a finite domain. The creation and propagation of elastic and thermoelastic waves in a finite domain and their effects on each other are investigated. Different relaxation times are chosen to briefly illustrate the events that take place in GL theory. Details of the formulation and numerical implementation are also presented.     

The effect of ethoxylated nonyl phenols on viscosity of crude oil

In this study, viscosities of different crude oils was determined in the temperature range of (298–373 K) in presence of ethoxylated nonyl phenols as nonionic surfactant with ethoxy group numbers 4 and 9 (nonyl phenol 4 and nonyl phenol 9). Viscosity was measured using Viscolab PVT viscometer. Viscosity of crude oil decreased with the increase of concentration in the range of 0–1.4 g l^?1). The most radical change was observed in the presence of nonyl phenol 9. For both surfactants, the viscosities of crude oil decreased with the increase of temperature, but the effect of temperature on the viscosity of crude oil decreased when surfactant concentration increased. Because of the formation of mixed micellar aggregates, the effect of mixed surfactants on the reduction of viscosity was more obvious than individual surfactant, but mixed surfactants had very little sensitivity to the temperature than individual surfactant. The best mixture of two surfactants system was observed in the mass ratio of 3 for nonyl phenol 9 and nonyl phenol 4.     

The effect of temperature on the interfacial tension between crude oil and ethoxylated nonylphenols

In this study, the effect of temperature on interfacial tension between crude oil and ethoxylated nonylphenols, with ethoxy group numbers of 4 and 9, was investigated. The interfacial tension was measured using the rising drop technique. Above the critical micelle concentration, the interfacial tension passed through a minimum when the temperature increased. Below the critical micelle concentration, the interfacial tension and time needed to reach equilibrium interfacial tension was reduced when the temperature increased. For a mixture of a two-surfactant system, interfacial tension was not sensitive to the temperature because of formation of mixed micellar aggregates.     

Suggestion of a New Correlation for the Height of Shallow Dispersion Bed Formed in a Rotating Disc Contactor

A rotating disc contactor (RDC) was designed and constructed. The obtained experimental results for the heights of shallow dispersion beds formed in the separation zone of the extraction column, suggested a new correlation. It was found that any increase in dispersed phase flow rate or rotor speed caused an increase in the dispersion height. Also, the results revealed the profound effect of the continuous phase viscosity on the height of the bed. Within the ranges of experimental results, the proposed correlation was in good agreement with the data of shallow beds compared to previous proposed relations.     

The effect of a short term saturated fat diet on the apoprotein composition and radioiodination properties of rat very low density lipoproteins

The effect of a saturated fat diet on the apoprotein composition and radioiodination properties of plasma very low density lipoprotein (VLDL) was studied in rats. After feeding the diet for 10 days, the proportion of¹²⁵I attached to VLDL lipid decreased from 50% (control animals) to 8%, the remainder (92%) being bound to the apoportein components. The decreased lipid labelling was associated with proportional changes in the fatty acid composition of serum and VLDL lipids, the most notable change being a reduction in linoleic acid (30–8%) content which occurred in all the major lipid classes of both serum and VLDL. Analysis of VLDL after radioiodination showed that most of the radioactivity incorporated into the lipid moiety was associated with phospholipid. The proportion of¹²⁵I bound to phospholipid decreased after feeding rats a saturated diet. The proportion of soluble (small molecular weight peptides and arginine rich peptide) to insoluble (B apoprotein) did not alter during the saturated fatty acid dietary regime and no differences in the distribution of soluble proteins were observed. It is concluded that feeding a saturated fat diet to rats for 10 days significantly improved¹²⁵I labelling of the apoprotein moiety while apparently not inducing changes in apoprotein composition.     

Silica nanostructured platform for affinity capture of tumor-derived exosomes

Early diagnosis of prostate cancer and evaluation of appropriate treatment options requires development of effective and high-throughput selective capture technology for exosomes that are positive for the expression of enzyme-biomarker, prostate-specific membrane antigen (PSMA). Exosomes are small secreted vesicles that play a key role in intercellular communication and cancer progression. PSMA is highly enriched in exosomes excreted by PSMA+ prostate cancer cells. Using PSMA+ cells from the well-established prostate cancer cell line (LNCaP), the secreted exosomes were collected and isolated from the culture medium. The tumor-derived exosomes were selectively captured using a novel silica nanostructure support that had been functionalized with the small-molecule ligand TG97, a known inhibitor of PSMA enzymatic activity that binds irreversibly in the active site of PSMA. The concept was demonstrated using a single cancer type (i.e., prostate cancer), but based on the data obtained the approach may be applicable to a broad panel of biomarker ligands for selective capture of biomarker-positive exosomes from an array of cell types. The approach demonstrated herein overcomes many of the limitations of alternative methods that are often ineffective in isolating tumor-derived exosomes from those derived from normal tissue because of the low yield recovery and the time required for the process. A further advantage is the ability to isolate a specific subpopulation of exosomes relying on the expression of a specific surface marker as well as improved exosome recovery rate.