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41.
A continued increase in the use of plastics has led to an increasing amount of plastics ending up in the waste stream; and
the increasing cost of landfill disposal and public interest in support of recycling has meant that plastics recycling must
increase. In this work, the effect of multiple extrusion and injection of poly(lactic acid)/polystyrene polymer blend (PLA/PS)
on its rheological and mechanical properties is presented. Rheological properties were studied using a capillary rheometer,
apparent shear rate (γ
a), apparent shear stress (τ
a), apparent viscosity (η
a), and flow activation energy were determined. The mechanical properties of the blend were investigated on dog bone-shaped
samples obtained by injection molding, tensile tests were performed, stress at break, strain at break, and Young’s modulus
were determined. The results showed that the apparent viscosity of PLA/PS blend decreases monotonously with increasing the
processing number. Also it was found that stress and strain at break of the blend decrease sharply after two processing cycles,
whereas the processing number has a little effect on Young’s modulus. 相似文献
42.
Anas M. Salhab Fawaz S. Al-Qahtani Salam A. Zummo Hussein Alnuweiri 《Wireless Personal Communications》2014,77(3):1751-1773
In this paper, we investigate the performance of a dual-hop fixed-gain amplify-and-forward relay system in the presence of co-channel interference at the destination node. Different fading scenarios for the desired user and interferers’ channels are assumed in this study. We consider the Rician/Nakagami- \(m\) , the Rician/Rician, and the Nakagami- \(m\) /Rician fading environments. In our analysis, we derive accurate approximations for the outage probability and symbol error probability (SEP) of the considered scenarios. The generic independent non-identically distributed (i.n.d.) case of interferers’ channels is considered for the Rician/Nakagami- \(m\) scenario; whereas, the independent identically distributed (i.i.d.) case is studied for the Rician/Rician and the Nakagami- \(m\) /Rician environments. Furthermore, to get more insights on the considered systems, high signal-to-noise ratio (SNR) asymptotic analysis of the outage probability and SEP is derived for special cases of the considered fading scenarios. Monte-Carlo simulations and numerical examples are presented in order to validate the analytical and asymptotic results and to illustrate the effect of interference and other system parameters on the system performance. Results show that the different fading models of interferers’ channels have the same diversity order and that the interference degrades the system performance by only reducing the coding gain. Furthermore, findings show that the case where the fading parameter of the desired user first hop channel is better than that of the second hop gives better performance compared to the vise versa case, especially, at low SNR values; whereas, both cases almost behave the same at high SNR values where the performance of the system is dominated by the interference affecting the worst link. Finally, results show the big gap in system performance due to approximating the Rician fading distribution with the Nakagami- \(m\) distribution which is an indication on the inaccuracy of making such approximations in systems like the considered. 相似文献
43.
FS Fawaz C van Ooij E Homola SC Mutka JN Engel 《Canadian Metallurgical Quarterly》1997,65(12):5301-5308
Infection of epithelial cells by two biovars of Chlamydia trachomatis results in the tyrosine phosphorylation of several host proteins. The most prominent change in host protein tyrosine phosphorylation involves a complex of proteins with molecular masses of 75 to 85 kDa (pp75/85) and 100 kDa (pp100). The C. trachomatis-induced tyrosine phosphorylation of pp75/85 and pp100 is observed in several cell lines, including epithelial cells, fibroblasts, and macrophages. Subcellular fractionation and detergent solubility properties of pp75/85 are consistent with its association with the cytoskeleton. Phosphoamino acid analysis demonstrates that the pp75/85 complex is phosphorylated on both tyrosine and serine residues. Immunofluorescence studies of chlamydia-infected cells by using fluorescein isothiocyanate-phalloidin and antibodies to phosphotyrosine and cortactin demonstrate that tyrosine-phosphorylated proteins, as well as cortactin, are localized to the chlamydial vacuole and that this process is facilitated by actin. 相似文献
44.
45.
Roger M. Touirat M. Ajram S. Pesant J.C. Linh N.T. Fawaz H. Salmer G. 《Electron Device Letters, IEEE》1999,20(5):203-205
In this letter, 0.35 μm gate length pseudomorphic AlGaAs/InGaAs/GaAs heterostructure insulated-gate field-effect-transistors (HIGFETs) have been fabricated on GaAs. The short-channel effects have been reduced by using a sidewall technology. A high current density and a high transconductance were obtained, reflectively, 510 mA/mm and 550 mS/mm, in addition to a high value of extrinsic current gain cutoff frequency FT=44 GHz. The dependencies of subthreshold current, threshold voltage, and output conductance on gate length have been emphasised 相似文献
46.
Naja Rola Mouawad Nadia Ghandour Ali J. Fawaz Kassem 《Wireless Personal Communications》2018,98(4):3563-3582
Wireless Personal Communications - During 2015, 35,092 people died in motor vehicle crashes on the U.S. roadways, an increase from 32,744 in 2014. The 7.2% increase is the largest percentage... 相似文献
47.
Lakhdar Bouchelouk Zouheir Riah David Baudry Moncef Kadi Anne Louis Blahcne Mazari 《国际射频与微波计算机辅助工程杂志》2008,18(2):146-156
A methodology to thoroughly characterize an electric near‐field probe based on small dipole antenna is presented. Both theoretical investigations and experimental direct measurements determine the various characteristics of the probe such as selectivity, sensitivity and spatial resolution. Results show the efficiency of the probe for diagnosing electromagnetic phenomena. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. 相似文献
48.
Chain transfer to monomer during nitroxide-mediated radical polymerization of styrene has been investigated for 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) and N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide (SG1) mediated polymerizations at 125 and 110 °C, respectively. A novel technique employing a fluorescence-labelled polystyrene-TEMPO macroinitiator enabled separate detection of the total chain distribution and the distribution of chains containing the original macroinitiator, thus directly confirming the presence of chains not containing macroinitiator. Chain transfer to monomer results in a low molecular weight tail, which can be very much pronounced, in particular in the number distributions. Quantitative analysis of the total number of chains in both the TEMPO and the SG1 systems, correcting for the contribution of thermal initiation of styrene, yielded chain transfer to monomer constants in agreement with the literature. 相似文献
49.
The availability of an optical connection is considered to be a critical service differentiator in WDM optical networks. In this regard, the design of a protection scheme that improves the availability of high priority optical connections and makes efficient use of optical resources is a major challenge faced by optical network operators. In a previous study, we proposed the so-called priority-aware shared protection survivability scheme as a potential solution to this design issue.In this paper, we complement our previous study. More specifically, we develop an offline study whose main purpose is to assess the efficiency of the priority-aware shared protection scheme. Through this study, we show that the priority-aware shared protection strategy as opposed to existing protection strategies is able to achieve the best tradeoff between optical resource usage and optical connections’ availability satisfaction. 相似文献
50.
We consider a two-stage assembly flowshop scheduling problem with the objective of minimizing a weighted sum of makespan and maximum lateness. The problem is known to be NP-hard, and therefore, we propose heuristics to solve the problem. The proposed heuristics are Tabu search (Tabu), particle swarm optimization (PSO), and self-adaptive differential evolution (SDE). An extensive computational experiment is conducted to compare performances of the proposed heuristics. The computational experiment reveals that both PSO and SDE are much superior to Tabu. Moreover, it is statistically shown that PSO performs better than SDE. The computation times of both PSO and SDE are close to each other and they are less than 40 and 45 s, respectively, for the largest size problem considered. 相似文献