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991.
992.
Mohammed S. Al-Jawad 《Polymer-Plastics Technology and Engineering》2013,52(4):501-511
Since the notation of pseudo pressure was introduced by Al-Hussainy and Ramey, the reverse calculation of pressure from its complementary pseudo pressure has become important. Up to the present time, the common way to do such a calculation has been to use a table of values. In this paper, a new technique is proposed for reverse calculation of pressure which employs the Newton-Raphson iterative method. In order to be practical, the iterative method is used in conjunction with an efficient method for pseudo pressure calculation. The proposed model is checked and its efficiency and practical applicability is evinced. 相似文献
993.
In this study the exact analytical solution of the lumped parameter model of a nonlinear heat transfer process representing the transient convective-radiative cooling of a spherical body has been obtained. The process is governed by a nonlinear ordinary differential equation, and the exact analytical solution has been found in the implicit form of an elementary transcendental function. The obtained exact analytical solution not only yields accurate results but also successfully simulates a recent experimental study of cooling of metallic ball bearings by the combined mechanism of convection and radiation. In addition, the exact explicit solution for a simplified case of the above problem, recently tackled by several researchers in various approximate ways, has also been found. These exact solutions are quite appealing since they are accurate and superior to the available approximate solutions, provide better insight of the physical process, and can also serve as yardsticks for future testing of the approximate solutions. 相似文献
994.
Bio-composites (PF) were successfully prepared by reinforcing poly lactic acid (PLA) with woven flax fibers (F) in the presence of mandelic acid, benzilic acid, dicumyl peroxide (DCP) and zein as additives. To improve the mechanical properties of the bio-composites, montmorillonite clay (MMT) was also added. Characterizations of the bio-composites in presence and absence of MMT were performed by FTIR, DSC, TGA and DMTA. The interfacial adhesion between the fibers and the matrix was qualitatively assessed from SEM micrographs of fractured specimens. Intercalation of MMT with 1.4 nm basal spacing was observed in the PLA matrix leading to the increased modulus and water resistance of the bio-composites. Results indicated that mandelic acid and dicumyl peroxide acted as efficient additives for this system. This work provided us the exploratory idea of using MMT in presence of amphiphilic compounds as additives in bio-composites for possible applications. 相似文献
995.
The design of controlled release polymer dispensers (CRPD) for effective release of the active ingredients at desired rates requires a careful study and generation of data on several properties of the polymer membranes. Presence of optimum tensile properties is one of the prerequisites for the CRPD in deciding their suitability for application in the fields. Polyvinylchloride (PVC) membranes containing di n-alkyl phthalate (alkyl= methyl, ethyl, butyl&octyl) with concentrations ranging from 10–30% with an increment of 2.5% were prepared. The tensile strength and percent elongation of these membranes as a function of concentration of the phthalate plasticizers, their size and aging period were performed. An increase in the tensile strength with increasing phthalate content was noticed up to 17.5% phthalate. Then followed a decrease with further increase of phthalate content. In contrast, the percent elongation was observed to increase constantly with increased concentration of the plasticizer. The ambiguous increase in the tensile strength up to 17.5% plasticized films is attributed to the antiplasticization effect of the plasticizer. The properties showed a linear behavior with respect to the size of the alkyl chain length and also the period of aging. The membranes with 17.5% and 20% were found to have optimum tensile properties and good property retention with aging for their application in controlled release of agrochemicals. 相似文献
996.
997.
This article is aimed at the investigation of electrical aging of polyesterimide under AC voltage using Weibull statistical analysis. It's shown that the time to breakdown characteristic (V–t) of polyesterimide includes two zones (segments of straight line). The first zone characterizes a statistical dispersion of the intrinsic defects of material. The second zone expresses the real aging of polymer. The variation of the slope of lifetime curve is attributed to the change in the degradation mechanism. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
998.
Anass Mouammine Satu Ojala Laurence Pirault-Roy Mohammed Bensitel Riitta Keiski Rachid Brahmi 《Topics in Catalysis》2013,56(9-10):650-657
Catalyst samples based on vanadium, cerium and titanium oxides were prepared using sol–gel method and wet impregnation. Several analytical techniques were used to characterize catalysts. The best activity and selectivity in the partial oxidation of methanol and methyl mercaptan were observed for the catalyst sample with the composition of 3 % V2O5/Ti0.1–Ce0.9O2. 相似文献
999.
Giuseppe Musumeci Paola Castrogiovanni Francesca Maria Trovato Annelie Martina Weinberg Mohammad K. Al-Wasiyah Mohammed H. Alqahtani Ali Mobasheri 《International journal of molecular sciences》2015,16(9):20560-20575
Cell death with morphological and molecular features of apoptosis has been detected in osteoarthritic (OA) cartilage, which suggests a key role for chondrocyte death/survival in the pathogenesis of OA. Identification of biomarkers of chondrocyte apoptosis may facilitate the development of novel therapies that may eliminate the cause or, at least, slow down the degenerative processes in OA. The aim of this review was to explore the molecular markers and signals that induce chondrocyte apoptosis in OA. A literature search was conducted in PubMed, Scopus, Web of Science and Google Scholar using the keywords chondrocyte death, apoptosis, osteoarthritis, autophagy and biomarker. Several molecules considered to be markers of chondrocyte apoptosis will be discussed in this brief review. Molecular markers and signalling pathways associated with chondroycte apoptosis may turn out to be therapeutic targets in OA and approaches aimed at neutralizing apoptosis-inducing molecules may at least delay the progression of cartilage degeneration in OA. 相似文献
1000.