Controlling the degree of sulfonation and its impact on hybrid cross-linked network based polyphosphazene grafted butylphenoxy as proton exchange membrane

A new hybrid based polyphosphazene backbone is synthesized via a series of reactions (ring opening of polyphosphazene, bromination, grafting groups, Atom transfer radical polymerization (ATRP) and sulfonation) with a controlled degree of sulfonation. The synthesis is proved via the ¹H NMR analysis at different steps. The corresponding membranes were elaborated via a casting method and characterized by ¹H NMR, FTIR, and XPS. Conductivity of the synthesized proton exchange membranes is as good as that of the commercial Nafion and displays at the same time a low swelling ratio and water uptake due to the cross-linking process. The membrane's activation energies are very low confirming the easy transport through the channels. As matter of fact, the morphology study reveals a well hydrophilic/hydrophobic nanophase separation. The present membranes are chemically and thermally very stable, no significant weight loss was observed after the Fenton's reagent test and no thermal degradation occurs at temperatures lower than 250 °C (considered high temperature for nowadays proton exchange membranes).     

Performance analysis of four-pad hydrostatic squeeze film dampers loaded between pads under laminar and turbulent flow conditions

This paper presents a theoretical study of the effects of Poiseuille Reynolds number and eccentricity ratio on the performance of four-pad hydrostatic squeeze film dampers. The finite difference method has been used to solve Reynolds equation based on Constantinescu’s turbulent lubrication theory. The numerical results obtained are analysed and compared between three and four-lobe hybrid journal bearings. The computed results indicate that the performance of a hydrostatic squeeze film damper loaded between pads is significantly influenced by the flow regimes. The results presented in this work can be useful to the bearing designers.     

Determination and analysis of the electrical components of a PEF treated equivalent circuit of potato tissue

The permeabilized membrane state of a pulsed electric field (PEF) treated biological sample is invisible to the naked eye, but can be deduced as the permeabilization causes loss of the insulating properties of the membrane, which can be determined by measuring the electrical impedance. This paper reports a spectroscopic analysis of a PEF treated and untreated potato sample to determine the electrical components of the biological tissue equivalent circuit model. The measurements concern flat potato samples which were subjected to different values of factors such as electric field, pulse number, pulse width and frequency. Cole–Cole plots are used to calculate the pore resistance and capacitance. This method of impedance measurement is used to establish the appropriate equivalent circuit model of the potato tissue according to the measured data, and thus explanations about the cell model from the impedance spectra are deduced. The PEF parameters had significant effect on the impedance and structural changes of the biological tissue. The treatment frequency does not have significant effect on the impedance when the electrical field, pulse number and width are kept constant.     

Microbial Quality of Industrial Liquid Egg White: Assumptions on Spoiling Issues in Egg‐Based Chilled Desserts

As a 1st step, this study aimed at investigating the microbial quality of liquid egg white in a French egg processing company. Thirty raw and 33 pasteurized liquid egg white samples were analyzed. Pasteurization was globally found efficient on mesophilic contaminants (1.7 ± 1.6 and 0.8 ± 0.9 log CFU/mL in raw and pasteurized samples, respectively), including for the control of Salmonella. However, Gram‐positive enterococci were still detected in the pasteurized samples. As a 2nd step, a representative bacterial collection was built for exploring the spoilage issue in egg‐based chilled desserts. Custard cream was chosen as growth medium since this food is widely used for the production of French chilled desserts. All of the 166 isolates of the bacterial collection were shown to be able to grow and to induce spoilage of the custard cream at refrigeration temperature (10 °C). Several spoilage types were highlighted in the custard cream, on the basis of changes regarding pH, consistency, production of holes or gas. As a 3rd step, bacterial enzymatic activities were explored on custard cream‐based agar media. The bacterial collection was reduced to 43 isolates, based on further selection regarding the genera and the spoilage types previously highlighted. Albeit to different degrees, all these isolates were able to produce proteases. A large part of these isolates also expressed lipolytic and amylolytic activities. This study emphasizes the need to control egg white contamination and especially with Gram‐positive heat‐resistant Enterococi, in order to guarantee the shelf life of egg‐based chilled desserts.     

Identification of the Main Degradation Products of Patulin Generated Through Heat Detoxication Treatments

The chemical stability of patulin (PAT) was studied in model aqueous media at different temperatures and pH values in the presence and absence of sulfites. At pH 6, 50% was degraded within one hour at 100°C. At lower pH the detoxication efficiency was strongly reduced. The compound 3‐keto‐5‐hydroxy‐pentanal was shown to be the main degradation product of patulin. As the hemiacetal function has to be transformed into an aldehyde before retroaldolization and lactone hydrolysis, sulfites, as expected, improved detoxication, especially at high pH. At pH 7 in the presence of 50 ppm sulfite, PAT was completely degraded within 3 h at 25°C.     

数据与模型协同驱动的智能光网络架构与关键技术

网络的规模升级和超大连接、超高带宽、超低时延应用的不断深化，对光传输网络资源利用和网络差异化服务提出了更高要求，使得传统模型驱动下的网络形态和配置方式面临挑战。基于数据与模型协同驱动思想，提出“3层3循环”架构及其“3可功能”特征的智能光网络技术方案，并对智能化实现技术展开研究，通过开发设计的智能传输网络平台对所提算法的性能进行测试，经验证，数据与模型协同驱动的智能光网络传输性能得到有效提升，为实现网络智能化提供了理论技术支撑。     

Isovalent Substitution and Heat Treatments Control of T c, Chain Oxygen Disorder and Structural Phase Transition in High T c Superconductors (Y1−x Nd x )SrBaCu3O6+z

We report here on the preparation, X-ray diffraction with Rietveld refinement, AC magnetic susceptibility measurements and effect of heat treatments in (Y_1?x Nd _x )SrBaCu₃O_6+z . Each sample was subject to two types of heat treatment: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. For each x, the [AO] heat treatment increases the orthorhombicity ε=(b?a)/(b+a) (for 0≤x<1), T _c (for x>0.2) and the distance d[Cu(1)–(Sr/Ba)] (decrease T _c) for x<0.25 and decrease it (increase T _c) for x>0.25. When x increase from 0 to 1, ε decreases to 0 with transition from orthorhombic to tetragonal structure. ε[O] decreases with T _c[O]. However, T _c[AO] decreases with ε[AO] until x=0.2, increases for x=0.4 and after it decreases by 9.8 K to 77.2 K for x=1 [AO]. Remarkable correlations were observed between T _c(x) and the volume of the unit cell V(x); and between δT _c(x)=T _c[AO]?T _c[O] and δε(x). A combination of several factors such as decrease in d[Cu(1)–(Sr/Ba)]; increase in cationic and chain oxygen ordering; the number p _sh(x) of holes by Cu(2)–O₂ superconducting plans and in-phase purity for the [AO] samples may account for the observed data.     

Computational fluid dynamic simulation of MVG tray hydraulics

The flow pattern and hydraulics of a Mini V-Grid valve (MVG) tray is predicted by using computational fluid dynamics simulation. A 3-D CFD model in the Eulerian framework was used. The simulation results for MVG tray are compared with that of sieve tray. The sieve tray geometry and operating conditions are based on the Solari and Bell’s sieve tray [1]. The MVG tray differs from that of Solari and Bell’s sieve tray solely by the difference in design of available openings for the flow of gas. The simulation results show that the clear liquid height and the pressure drop of MVG tray are lower than that of sieve tray whereas the liquid velocity is higher and contacts of phases are good. The simulation results of sieve tray are in agreement with the experimental data of Solari and Bell [1].     

G.719: The First ITU-T Standard for High-Quality Conversational Fullband Audio Coding

This article presents an overview of the recently standardized ITU-T G.719 codec, its key technologies, and their impact on audio quality. These technologies, while leading to exceptionally low complexity and small memory footprint, result in high fullband audio quality, making the codec a great choice for any kind of communication devices, from large telepresence systems to small low-power devices for mobile communication.