Investigation on the effect of process parameter on physical properties of RF-sputtered Mo–Ni thin films as a back contact thin-film solar cell

Journal of Materials Science: Materials in Electronics - In this work, the influence of RF power and deposition time on the structural, chemical, morphological, optical, and electrical properties...     

Combining Radial Basis Function Neural Network Models and Inclusive Multiple Models for Predicting Suspended Sediment Loads

Water Resources Management - An important issue in water engineering is predicting suspended sediment load (SSL). For the Telar River and its tributaries, this study employs an inclusive multiple...     

Effect of copper nanoparticles on thermal behavior of two-phase argon-copper nanofluid flow in rough nanochannels with focusing on the interface properties and heat transfer using molecular dynamics simulation

A comparison between the efficacy of surface boundary structure and presence of nanoparticles on the condensation two-phase flow inside rough nanochannels has been accomplished by applying molecular dynamics procedure to evaluate the thermal conductivity and flow characteristics. Simulation is performed in a computational region with two copper walls containing rectangular rough elements under different saturated temperatures. The main properties of liquid-vapor interface including density and the number of liquid atoms, are obtained. It is observed that the density profile is more affected by nanoparticles than the roughness. Also, compared to the condensation of nanofluid in a smooth nanochannel, the rough wall causes a greater drop in the temperature at the early time steps and by development of liquid films, effects of the wall roughness reduce. At the first of the condensation process, adding nanoparticle causes that transferring argon particles to the liquid phase increases with a steeper slope. Furthermore, heat current autocorrelation function (HCACF) for nanofluid condensation flow over considered correlation time is analyzed and following that the thermal conductivity for different saturated conditions is calculated. It has been represented that at lower temperatures the roughness makes more significant influence on the heat transfer of two-phase flow, while at higher temperatures the importance of nanoparticles prevails.     

New polyamides based on 2,5‐bis[(4‐carboxyanilino) carbonyl] pyridine and aromatic diamines: Synthesis and characterization

Seven new polyamides 6a–g were synthesized through the direct polycondensation reaction of 2,5‐bis[(4‐carboxyanilino) carbonyl] pyridine 4 with seven derivatives of aromatic diamines 5a–g in a medium consisting of N‐methyl‐2‐pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel polyamides containing pyridyl moiety in the main chain in high yield with inherent viscosities between 0.32 – 0.72 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis and differential thermal gravimetric. All the polymers were soluble at room temperature in polar solvents, such as N,N‐dimethyl acetamide, N,N‐dimethyl formamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone. 2,5‐Bis[(4‐carboxyanilino) carbonyl] pyridine 4 as a new monomer containing pyridyl moiety was synthesized by using a two‐step reaction. At first 2,5‐pyridine dicarboxylic acid 1 was converted to 2,5‐pyridine dicarbonyl dichloride 2 . Then diacid 4 was prepared by condensation reaction of diacid chloride 2 with p‐aminobenzoic acid 3. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

New photosensitive poly(amid‐imide)s containing chalcone moiety and hydantoin derivatives in the main chain: Synthesis and characterization

Six new poly(amid‐imide)s containing chalchone and hydantoin moieties in the main chain were synthesized through the polycondensation reaction of 1,3‐bis[4,4′‐bis(trimellityimido)phenyl]‐2‐propenone 6 with six hydantoin derivatives 7a‐f in a medium consisting of triphenyl phosphite, calcium chloride, pyridine, and N‐methyl‐2‐pyrrolidone. The polycondensation reaction produced a series of novel poly(amid‐imide)s 8a‐f in high yields with inherent viscosities between 0.26 and 0.42 dL/g. The resulting polymers were characterized by elemental analysis, viscosity measurements, solubility test, thermo gravimetric analysis (TGA and DTG), FTIR, and UV‐Vis spectroscopy. 1,3‐bis[4,4′‐bis(trimellityimido)phenyl]‐2‐propenone 6 was prepared from a three‐step reaction by using 4‐nitro benzaldehyde 1 and 4‐nitro acetophenone 2 as precursors. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

燃料稀释对传统型和高预热空气稀释型燃烧炉性能的影响的数值研究

This numerical study investigates the effects of using a diluted fuel (50% natural gas and 50% N2) in an industrial furnace under several cases of conventional combustion (air with 21% O2 at 300 and 1273 K) and the highly preheated and diluted air (1273 K with 10% O2 and 90% N2) combustion (HPDAC) conditions using an in-house computer program. It was found that by applying a combined diluted fuel and oxidant instead of their uncombined and/or undiluted states, the best condition is obtained for the estab-lishment of HPDAC’s main unique features. These features are low mean and maximum gas temperature and high radiation/total heat transfer to gas and tubes; as well as more uniformity of theirs distributions which results in decrease in NOx pollutant formation and increase in furnace efficiency or energy saving. Moreover, a variety of chemical flame shape, the process fluid and tubes walls tem-peratures profiles, the required regenerator efficiency and finally the concentration and velocity patterns have been also qualita-tively/quantitatively studied.     

Antibacterial activity of natural polymer gels and potential applications without synthetic antibiotics

Antibiotics' use has increased, resulting in disadvantages like patients' drug resistance. Consequently, urgent action is required to develop a new generation of antibacterial agents. Most antibacterial platforms still require a modification with further antibacterial agents (e.g., antibiotics) for adequate antibacterial efficiency. Thus, a nonantibiotic methodology is immediately needed. Furthermore, bactericidal agents used for this purpose are usually based on metal nanoparticles, carbon materials, and polymers. Still, chemicals, antibiotics, and biocides lead to environmental damage. Therefore, the help of biocompatible yet durable materials and polymers is highly appreciated. In addition, if a polymer is not biodegradable, it will remain in the environment for more than one hundred years due to its low degradation rate. Moreover, non-biodegradable polymers are harmful to in vivo applications. Hence, the use of biodegradable and non-toxic materials has received many considerations. Over the last few years, the design and synthesis of new polymer gels have gained increasing attention. A polymer gel, also known as a hydrogel, is a three-dimensional and cross-linked network filled with water or other liquid solvents. Besides, the hydrogels supercritical drying method results in aerogels, and the freeze-drying method generates cryogels, where their porous and sponge-like structures are preserved. Additionally, antibacterial polymer gels are a new generation of polymers considered attractive due to their unique properties. The most recent studies and the latest innovations in polymer gels and hybrid polymers with intrinsic antibacterial properties were discussed in the present review. The reviewed studies from 2015 to April 2022 showed a tremendous revival in research about biopolymer hydrogel, aerogel, and cryogel as antibacterial agents.     

An RTM densification method of manufacturing carbon-carbon composites using Primaset PT-30 resin

This paper presents a development of carbon-carbon (C-C) composite by resin transfer molding (RTM) process. The RTM was used for both manufacturing of the resin matrix composite part as well as impregnation of the carbonized parts. Materials chosen were heat-treated T300 2-D carbon fabric and Primaset PT-30 cyanate ester. The PT-30 resin has a char yield similar to that of phenolics, very low volatiles, low viscosity at processing temperatures, and no by-products during cure, and hence, an excellent choice for RTM process. The process consists of RTM of the composite part, carbonization, RTM impregnation, and re-carbonization. The last two steps were repeated to achieve the desired density. The measured density and mechanical properties of just two times-densified C-C composite panels were superior to or nearly the same as the data in the literature by other processes. The RTM densification is about twice as fast as the resin solution method and it is environment friendly.     

Dynamic mathematical modeling of a novel dual-type industrial ethylene oxide (EO) reactor

In this paper, the dynamic behavior of a novel dual-type industrial ethylene oxide reactor has been proposed with taking catalyst deactivation into account. The configuration of two catalyst beds instead of one single catalyst bed is developed for conversion of ethylene to ethylene oxide. In the first reactor which is an industrial fixed-bed water-cooled reactor, the feed gas is partly converted to ethylene oxide. This reactor functions at very high yield and at a higher than normal operating temperature. In the second converter, the reaction heat is used to preheat the feed gas to the first reactor and a milder temperature profile is observed. The potential possibilities of a two-stage catalyst bed system are analyzed using a 1D heterogeneous dynamic model to obtain necessary comparative estimates. A differential evolution (DE) algorithm is applied as an effective and robust method to optimize the reactors length ratio. The results obtained from the simulation demonstrate that there is a desirable catalyst temperature profile along the dual-type reactor (DR) compared with the conventional single-type reactor (SR). In this way, the catalysts are exposed to less extreme temperatures and thus, diminishing the catalyst deactivation via sintering. Results from this study provided beneficial information about the effects of reactors configuration on catalyst lifetime and ethylene oxide production rate simultaneously.     

Preparation and Characterization of Poly(bisphenol A oxalate) and Studying its Chelating Behavior Towards Some Metal Ions

Abstract

Poly(bisphenol A oxalate) was synthesized by condensation polymerization of Bisphenol A and oxalyl chloride in dichloromethane under dry nitrogen atmosphere below 5°C. The resulting linear alternating polymer was characterized by inherent viscosity, FTIR, ¹H‐NMR, and ¹³C‐NMR. The thermal behavior of the polymer was evaluated by differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The chelating behavior of the synthesized polymer towards some divalent metal ions was studied by the batch equilibrium technique as a function of pH and contact time. The isothermal behavior and kinetics of the metal ions uptake onto the polymer were also investigated. The polymer showed high rates of metal ion uptake toward Pb(II), Cu(II), and Mg(II), but low rates toward Ni(II) and Cd(II) in the measurement of metal uptake. Interestingly, the polymer was found to selectively chelate Pb(II) and Mg(II) ions in the concentration variation isotherm experiments.