This study presents a comprehensive analysis of the entropy of condensed phases, its temperature, pressure, and composition dependence on a macroscopic correlative platform. Two principal contributions to total nonconfiguration entropy (ST) are outlined. They are: (i) the pure thermal (Sth) contribution arising from the isochoric temperature dependence of Gibbs energy (GT) and (ii) the elastic contribution (Sel) representing the dilatational volume effects. It is then argued that entropy variation among a group of alloy phases can be exclusively related to molar volume, only when both thermal pressure (pth) and thermal entropy terms assume common values for all members. This argument is extended to establish a linear relationship between transformation entropy (ΔStr) and transformation-induced volumetric strain (ΔVtr/V). The temperature and pressure dependencies of entropy have been discussed in terms of the complementing roles of Sth and Sel and simple approximations to these effects are suggested. A macroscopic power law relation for systematizing the standard entropy variation using a composite scaling parameter (MV2/3/Tm) has been proposed, and its validity is demonstrated for both solid and liquid metals. This power law correlation has been exploited to deduce the following outcome: (i) a simple approximation for the initial slope (dp/dTm) of p–Tm melting curve, (ii) self-consistent correlation of entropy with specific heat and Debye temperature, (iii) estimation of entropy of metastable phases, and (iv) correlating dilute solution entropy with volume effects of alloying.
The role of inner-layer (interphase) in fiber-reinforced composites is often assessed by measuring the interfacial shear strength of single fibers embedded in matrix blocks. Interfacial shear strength is calculated using simple shear lag analyses (Kelly and Tyson model). This paper shows that application of Kelly and Tyson's equation may result in gross overprediction of interfacial shear strengths if the thickness of the inner-layer is not negligible in comparison with the fiber diameter. 相似文献
Shrimp oil is extracted from shrimp (Litopenaeus vannamei) cephalothorax and subjected to the removal of cholesterol by β‐cyclodextrin (βCD). Different oil/βCD ratios (1:2, 1:3, and 1:4, w/w) and homogenization times (1, 10, and 20 min) are used. Cholesterol deduction is attained with increasing βCD levels and homogenization time. Astaxanthin content is augmented, while cholesterol concentration is reduced. Nevertheless, oil yield and astaxanthin concentration of treated oil are decreased as βCD levels are increased. To increase the oil yield, the used βCD is further extracted for three times with ethyl acetate at 1:10 (w/v) ratio, in which yield is increased from 44.6% to 64%. Cholesterol removal of 95% is obtained, while astaxanthin content is increased. Lipid oxidation is lowered as indicated by the lower TOTOX value, peroxide value, thiobarbituric acid reactive substances, and p‐anisidine value. However, lipid hydrolysis is slightly increased after treatment. Volatiles, especially aldehydes and alcohols, are decreased after treatment. FTIR spectra confirm the removal of phospholipid, which might be associated with the decreased oil yield after treatment. With the developed process, total fatty acid is increased by 15.6%, in which monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) are augmented. βCD could remove cholesterol, increase astaxanthin and fatty acid content. Practical Applications: Shrimp oil has been known to be a rich source of astaxanthin and PUFAs with health benefit. However, it also contains cholesterol, which can be a drawback for consumption as the supplement. The removal of cholesterol, while maintaining PUFA and astaxanthin could pave a way for promoting the intake of shrimp oil. Use of βCD for oil treatment with subsequent extraction of remaining oil in the used βCD could be implemented with ease. Another advantage of the developed process is to increase both fatty acid and astaxanthin contents in the resulting oil. As a consequence, shrimp oil with lowered cholesterol can be directly used as food ingredient and also for neutraceutical purpose. 相似文献
Gum karaya and gum kondagogu are the two important commercial tree gums of India. The amino acids and fatty acid profiles of gum kondagogu and gum karaya were investigated by preparing their corresponding N-O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatives for amino acids and direct trans-esterification of methyl esters for fatty acids and their subsequent analysis by a GC–MS method. The amino acids, such as, alanine, valine, methionine, tyrosine and tryptophan, were not detected in gum karaya as they were in gum kondagogu. Interestingly, the aspartic acid content (72.8 ± 3.45 μg/g) of gum kondagogu was higher than that of gum karaya (64.2 ± 2.44 μg/g). The ratios of saturated to unsaturated fatty acid in gum kondagogu and gum karaya were found to be 5:1, and 6.6:1, respectively. Among the unsaturated fatty acids, linoleic acid (1.8 ± 0.12 μg/g) and γ-linolenic acid (0.8 ± 0.05 μg/g) were detected only in gum kondagogu. Arachidic acid was not detected in gum karaya. Additionally, the presence of linoleic acid and γ-linolenic acid in gum kondagogu reinforces its nutritional value. 相似文献
The photocatalytic production of H2 using carbon-doped TiO2 (CTiO2) nanoparticles has been investigated in single or mixed systems of organic fatty acids (OFAs) under visible light irradiation, including acetic acid, propionate acid, butyric acid and lactic acid. When OFAs were applied at the same electron density (10 e-eq L?1), the H2 evolution rates followed the order of propionic acid > butyric acid ≈ acetic acid > lactic acid, whereas at the same molar concentration (0.5 mol L?1), that order changed to lactic acid > acetic acid > butyric acid ≈ propionic acid. This result implied that the electron transfer efficiency differed from four OFAs, probably due to their different affinity with CTiO2. O2?? and CH3? partially contributed to OFAs degradation and H2 production. The quantum dynamics simulations of electron transfer revealed that the dominant mechanism of H2 production was direct electron transfer from adsorbed OFAs to CTiO2. This work aims to pursue the synergy of solar energy utilization and conversion of OFAs into H2. 相似文献
An analysis has been carried out to investigate the effect of homogeneous‐heterogeneous reactions and induced magnetic field on the unsteady two‐dimensional incompressible nonlinear thermal convective velocity slip flow of a Jeffrey fluid in the presence of nonlinear thermal radiation and heat source/sink. We assumed that the flow is generated due to injection at the lower plate and suction at the upper plate. We obtained a numerical solution for the reduced nonlinear governing system of equations via the shooting technique with fourth‐order Runge‐Kutta integration. We plotted the graphs for various nondimensional parameters, like Deborah number, heat source/sink parameter, nonlinear convection parameter, nonlinear radiation parameter, magnetic Reynolds number, Strommer's number, velocity slip parameter, strengths of homogeneous, heterogeneous reaction parameters and skin friction over the nondimensional flow, temperature, concentration profiles and magnetic diffusivity fields. Also, we calculated the numerical values of boundary properties, such as the skin friction and heat transfer rate. We noticed that the temperature of the fluid is enhanced with the radiation parameter, whereas the concentration decreases with increase of the magnetic Reynolds number. The present results have good agreement with published work for the Newtonian case. 相似文献
Drug which shows extensive first pass effect is difficult task that, needs to be solved by formulators in the pharmaceutical science. The low oral bioavailability (49%) of flutamide may be due to poor wettability, low aqueous solubility and extensive first pass effect. The aim of present investigation was to prepare flutamide loaded microspheres and incorporate it into suppositories for rectal delivery to avoid first pass effect and enhance residence time. Flutamide loaded mucoadhesive microspheres of Ocimum Basilicum mucilage (OBM) were prepared using spray drying and characterized by percent production yield, encapsulation efficiency, particle size, zeta potential, polydispersity index, DSC, SEM, XRPD, in vitro drug release and stability studies. Moreover, ex vivo mucoadhesion was investigated using falling liquid film technique to determine the adhesion of microspheres to sheep rectal mucosa. The microspheres had nearly spherical shape and size about 2.53?μm. The encapsulation efficiency and mucoadhesion of optimized formulation MBF10 were found to be 69.6?±?2.3% and 89.01?±?2.18%, respectively. Percent CDR of optimized flutamide loaded mucoadhesive microspheres was found to be 88.7?±?1.3 at 7?h. In conclusion, OBM microparticles based suppository could be used to deliver drug through rectal delivery. 相似文献
In this work, we construct electrodes of brass to produce plasma by arc discharge and is characterized by using a movableLangmuir single probe. It is a simple w... 相似文献