Enrichment of heavy water in flat‐plate thermal diffusion columns of the frazier scheme with the optimal plate aspect ratio for best performance

The solutions of the optimum plate aspect ratio as well as the corresponding maximum separation, maximum production rate and minimum plate surface area in thermal diffusion columns of the Frazier scheme for enrichment of heavy water have been obtained, analogous to those obtained in the previous work for separation of a binary system. It was found that all the optimum plate aspect ratios do not depend on feed concentration, while the corresponding best performances do. It is found that considerable improvement in performance is obtained when the operation is carried out with the optimal plate aspect ratio.     

Short term load forecasting using a multilayer neural network withan adaptive learning algorithm

A multilayer feedforward neural network is proposed for short-term load forecasting. To speed up the training process, a learning algorithm for the adaptive training of neural networks is presented. The effectiveness of the neural network with the proposed adaptive learning algorithm is demonstrated by short-term load forecasting of the Taiwan power system. It is found that, once trained by the proposed learning algorithm, the neural network can yield the desired hourly load forecast efficiently and accurately. The proposed adaptive learning algorithm converges much faster than the conventional backpropagation-momentum learning method     

<Emphasis Type="Italic">Abies koreana</Emphasis> Essential Oil Inhibits Drug-Resistant Skin Pathogen Growth and LPS-Induced Inflammatory Effects of Murine Macrophage

Since acne vulgaris is the combined result of a bacterial infection and the inflammatory response to that infection, we examined whether Abies koreana essential oil (AKE) possessed anti-inflammatory and antibacterial activities against skin pathogens. In this study, AKE showed excellent antibacterial activities against drug-susceptible and -resistant Propionibacterium acnes and Staphylococcus epidermidis, which are acne-causing bacteria. In addition, AKE reduced the LPS-induced secretion of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, NO and PGE₂ in RAW 264.7 cells, indicating that it has anti-inflammatory effects. Therefore, we suggest that AKE may be an attractive candidate for promoting skin health.     

Boron Nitride-Based Overcoat Thick Films for MoSi2 Planar Heating Elements

This work first reports a boron nitride-based dielectric system that is designed for MoSi₂–based planar heating elements patterned on a regular 96% alumina substrate. The dielectric system is expected to function as an overcoat layer mainly to protect the printed heating elements from environments and to reduce thermal stress induced during thermal heating through improved heat dissipation. The boron nitride (BN) pastes mixed with a low softening glass of calcium barium aluminoborosilicate were screen printed onto MoSi₂ thick films and then fired at a temperature of 900°C. The addition of BN was found to increase the thermal conductivity considerably without detrimental chemical reactions with glass constituents. For instance, the thick film containing 30 wt% BN was regarded as a promising composition from the supporting evidences of good adhesion with MoSi₂, an increased thermal conductivity of ∼31 W·(m·K)⁻¹, and a high electrical resistance of 4.7 × 10¹⁰Ω.     

Immobilization of TiO2 on an ITO substrate to facilitate the photoelectrochemical degradation of an organic dye pollutant

In this study, we developed an immobilized TiO₂ semiconductor on an ITO glass substrate (TiO₂/ITO) and investigated its photocatalytic and electrochemical performance. The TiO₂/ITO samples were prepared via a spin-coating process followed by calcination and were used for the photocatalytic or electrochemical degradation of an organic dye pollutant. The measured photocatalytic performance was comparable to that reported in previous publications; however, a remarkable result was obtained in our electrochemical system. The formation of hydroxyl radicals (OH) strongly dominated the electrochemical system, which resulted in outstanding degradation performance. Therefore, we propose a commercializable photoelectrochemical system that can maximize the degradation of pollutants in wastewater treatment plants.     

Microstructure and ultimate properties of injection molded amorphous engineering plastics: Poly(ether imide) and poly(2,6-dimethyl-1,4-phenylene ether)

Specimens of two engineerig plastics i.e., poly(ether imide), PEI, and poly(2,6-dimethyl- 1,4-phenylene ether), PPE, were injection molded employing a 40t Van Dorn injection molding machine and industrial practices. The mold and melt temperatures and the injection speed were varied in a limited range which furnished acceptable samples. The density, birefringence, residual stress distributions, flexure and tensile properties, and crack development of the injection molded specimens were studied. Vacuum compression molded samples were also prepared to investigate the role played by the cooling rate in shaping microstructural distributions. The results revealed significant differences in the development of microstructure of the molded specimens of the two resins, which was related to rheology and molding conditions on one hand and to development of cracks and ultimate properties on the other hand.     

Effects of gamma irradiation on the thermal and mechanical properties of chitosan/PVA nanofibrous mats

Chitosan/poly(vinyl alcohol) (PVA) nanofibrous mats were prepared by the electrospinning method. The morphology and structure of electrospun nanofibers were investigated by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. SEM images showed that the uniform and bead-free fibers were obtained at concentrations greater than 8 wt%. Chitosan/PVA mats were irradiated with different doses (50–200 kGy) of ⁶⁰Co gamma rays. The effect of irradiation dose on the mechanical and thermal properties of these films was also investigated. Increasing the irradiation dose led to a decrease in tensile strength. FT-IR and DSC demonstrated that there were strong intermolecular hydrogen bonds between the chitosan and PVA molecules.     

Aerosol-assisted flow synthesis of B-doped, Ni-doped and B–Ni-codoped TiO2 solid and hollow microspheres for photocatalytic removal of NO

In this study, highly effective B-doped, Ni-doped and B–Ni-codoped TiO₂ microspheres photocatalysts were directly synthesized via an aerosol-assisted flow synthesis method. The resulting samples were characterized by XRD, SEM, TEM, UV–vis diffuse reflectance spectroscopy, nitrogen adsorption and XPS. The characterizations revealed hollow microspherical structure of the B-doped and B–Ni-codoped TiO₂ photocatalysts, while the Ni-doped and undoped TiO₂ products consisted of solid microspheres. It was found that the boron dopant was partially embedded into the interstitial TiO₂ structure, existing in the form of Ti–O–B structure. The band gap was enlarged after the boron doping. However, both Ni-doped and B–Ni-codoped TiO₂ samples showed obvious red shift in their absorption edges because of the Ni doping. The photocatalytic activities of these samples were evaluated on the photocatalytic removal of NO under simulated solar light irradiation. All the aerosol-assisted flow synthesized samples had much higher photocatalytic activities than P25 and the doped TiO₂ microspheres exhibited enhanced photocatalytic activity than the undoped counterparts. More interestingly, the B–Ni-codoped TiO₂ photocatalyst possessed superior photocatalytic activity to the as-prepared single doped TiO₂ products. The enhanced photocatalytic activity was explained and the formation mechanisms of hollow and solid microspheres were also proposed on the basis of characterizations. We think this general method may be easily scaled up for industrial production of highly active microspherical photocatalysts for efficient NO removal under simulated solar light irradiation.     

Theoretical analysis of the effects of asymmetric membrane structure on fouling during microfiltration

There is a growing interest in the use of both asymmetric and composite membranes for microfiltration and ultrafiltration processes. This includes particle removal applications in the semiconductor industry and virus clearance in biopharmaceutical applications. Filter fouling plays an important role in these processes. Although flux decline models have been developed for homogeneous membranes, the effects of asymmetric membrane structure on flux decline behavior remain poorly understood on a fundamental level. Here, we develop a theoretical model to describe the effects of asymmetric membrane structure on flux decline. The asymmetric structure was described by the spatial variation in Darcy permeability in the directions normal to and parallel to the membrane surface. The velocity profile and flux decline because of pore blockage were described using Darcy's law and a pore blockage and cake filtration model. Flux decline data were obtained using pseudocomposite membranes with highly interconnected polyvinylidene fluoride membranes (PVDF) and straight through pore polycarbonate track‐etched membranes (PCTE). Model composite membranes were formed by layering PCTE or PVDF membranes with different pore sizes on top of each other. Flux decline data for the composite membrane were in good agreement with model calculations. The results provide important insights into the effects of asymmetric membrane pore structures on flux decline. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

High yield synthesis of diverse well‐defined end‐functionalized polymers by combination of anionic polymerization and “click” chemistry

Well‐defined poly(methyl methacrylate) (M_n = 3630 g mol^?1, PDI = 1.06) with a primary benzylic bromide prepared using anionic polymerization was successfully transformed into diverse end‐functionalities (ω‐carboxyl, ω‐hydroxy, ω‐methyl‐vinyl, ω‐trimethylsilane, and ω‐glycidyl‐ether) via “click” reaction. The bromine end‐terminated poly(methyl methacrylate) was first substituted by an azide function and sequentially was reacted with various functional alkynes (propiolic acid, propargyl alcohol, 2‐methyl‐1‐buten‐3‐yne, propargyl trimethylsilane, and propargyl glycidylether). In all the cases, ¹H‐NMR, ¹³C NMR, FT‐IR, and GPC measurements show qualitative and quantitative transformation of the chain‐end poly(methyl methacrylate) into the desired functionalities with high conversion (above 99%). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009