Review of Capabilities of the ENEPIG Surface Finish

Surface finishes are used to protect exposed copper metallization in printed circuit boards from oxidation and to provide a solderable surface on which to mount electronic components. While it is true that some people have called electroless nickel electroless palladium immersion gold (ENEPIG) a “universal finish” for a wide range of applications from wire bonding to solder interconnects, this paper provides a review of the current literature on ENEPIG and assesses its overall capabilities compared to other surface finishes. Gaps in understanding the performance of ENEPIG as a printed wiring board surface finish are identified and further testing is recommended.     

On the Friction of Carbon Black- and Silica-Reinforced BR and S-SBR Elastomers

Friction of carbon black- and silica-reinforced elastomers is studied experimentally and theoretically, using Persson’s model. The effect of reinforcement fillers on elasticity was determined by dynamical mechanical analysis. Carbon black-filled samples have a higher Young’s modulus than the silica-filled compounds. Silica-filled rubbers have a higher tan (δ) at lower temperatures and a lower loss tangent at higher temperatures, which is a rough indication for higher wet grip and lower rolling resistance, respectively. Friction tests on a ball-on-disk test rig were performed to study the effect of the reinforcement fillers and their amount on the friction between rubber samples (disks) and relatively smooth or rough granite surfaces (balls). The results were discussed and compared with the friction model presented by Persson. It was shown theoretically and experimentally that hysteresis does not play a significant role in the friction of rubber samples in contact with smooth granite and that it plays a minor role in contact with a rough granite sphere. Therefore, the hysteresis contribution of friction can be neglected in the contact of rubbers with just smooth spheres. Moreover, a higher friction coefficient is seen in samples with a higher content of fillers. Silica-filled compounds show a slightly higher coefficient of friction compared with the carbon black-filled compounds. The effect of attached wear debris to the granite surfaces on the friction level has been studied. The results are supported by SEM and confocal microscopic images of the wear debris itself and wear debris attached to the granite spheres, respectively.     

Ozone in wineries and wine processing: A review of the benefits,application, and perspectives

Ozone (O₃) is an emerging eco-friendly technology that has been widely used in the beverage industry due to its broad spectrum of usages, such as fermentation, microbial inactivation, Clean-in-Place (CIP) systems, and postharvest treatment. Wine is among the most financially profitable sectors of the beverage industry. Ozone technology as an alternative approach to conventional methods to inhibit microbes in wine processing and wineries has attracted researchers' attention as this emerging technology will probably play important roles in wineries in the future. This review discusses the prospective applications of ozone in winemaking and wineries and elaborates on ozone's antimicrobial effects on the control of the broad spectrum of microorganisms during wine processing. Also, this paper provides discussions on its effects of O₃ on wine quality and the benefits this emerging technology can bring to wineries. Ozone treatments can improve yeast fermentation by impacting the yeast ecology of postharvested wine grapes, mainly by affecting apiculate yeasts and adjusting the population of undesirable yeasts, such as Brettanomyces spp., during the fermentation process. Furthermore, ozone treatment may enhance wine's anthocyanin concentration, physicochemical properties, color, pH, oxidative stability, and concentration of pleasant volatile compounds and esters. This article presents important information to have a better understanding of the impact of ozone treatment on different stages of wine preparation.     

Neural computing approach for estimation of natural gas dew point temperature in glycol dehydration plant

ABSTRACT

Hydrate formation and water accumulation during transmission process can be prevented by effective dehydration of gas streams. This study investigates the application of multi-layer perceptron artificial neural network to estimate natural gas dew point temperature using contactor temperature and TEG purity as independent variables. A dataset comprised of 173 data points is extracted from the literature. The proposed model is considered a great help for engineers to have precise dew point temperature predictive tool in wide ranges of concerning variables. Results obtained from the proposed model show R-squared and mean square error of 1.000 and 0.156, respectively. Accordingly, the remarkable agreement between predicted and experimental values is observed.     

Dynamic contact angle of water-based titanium oxide nanofluid

This paper presents an investigation into spreading dynamics and dynamic contact angle of TiO₂-deionized water nanofluids. Two mechanisms of energy dissipation, (1) contact line friction and (2) wedge film viscosity, govern the dynamics of contact line motion. The primary stage of spreading has the contact line friction as the dominant dissipative mechanism. At the secondary stage of spreading, the wedge film viscosity is the dominant dissipative mechanism. A theoretical model based on combination of molecular kinetic theory and hydrodynamic theory which incorporates non-Newtonian viscosity of solutions is used. The model agreement with experimental data is reasonable. Complex interparticle interactions, local pinning of the contact line, and variations in solid–liquid interfacial tension are attributed to errors.     

Fear conditioning and extinction: Influence of sex and menstrual cycle in healthy humans.

Although sex differences have been demonstrated in behavioral paradigms of fear conditioning, the findings have been inconsistent, and fear extinction has been little studied. The present study investigated the influence of sex and menstrual cycle phase on the recall of fear extinction. Three groups of healthy adult participants were studied: women at 2 different phases of the menstrual cycle (early follicular [early cycle] and late follicular [midcycle]) and men. Participants underwent a 2-day fear conditioning and extinction protocol. The paradigm entailed habituation, fear conditioning, and extinction learning on Day 1 and extinction recall and fear renewal on Day 2. Skin conductance served as the dependent variable. During fear acquisition on Day 1, men showed significantly larger conditioned responses relative to women; early cycle and midcycle women did not differ. No significant group differences were found during extinction learning. On Day 2, men and early cycle women expressed greater extinction memory than midcycle women. These data confirm sex differences in conditioned fear acquisition and suggest that midcycle hormones attenuate extinction recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and characterization of poly(methylene disulfide) and poly(ethylene disulfide) polymers in the presence of a phase transfer catalyst

Poly(methylene disulfide) and poly(ethylene disulfide) were synthesized from the polycondensation of methylene dichloride and ethylene dichloride monomers, respectively, in the presence of benzyltriethylammonium chloride as a phase transfer catalyst. The structures of the synthesized polysulfides were confirmed via the elemental analysis, attenuated total reflectance Fourier transform infrared spectroscopy and X-ray diffraction techniques. Moreover, the thermal behaviors of synthesized poly(methylene disulfide) and poly(ethylene disulfide) were characterized using differential scanning calorimetry and thermogravimetric analysis methods. The synthesized poly(methylene disulfide) and poly(ethylene disulfide) have molecular weights of about 2262 and 2863 g/mol, respectively. In addition, the polymers have crystalline structures absorbed in the amorphous sections. However, the d-spacing of polymers’ crystalline parts was different. Moreover, poly(methylene disulfide) and poly(ethylene disulfide) have a two- and one-step degradation behavior, respectively.