Catalytic wet air oxidation of phenol by CeO2 catalyst--effect of reaction conditions

The effect of catalyst loading, oxygen pressure, reaction temperature and phenol concentration on phenol conversion and total organic carbon (TOC) conversion, using CeO(2) as the catalyst, was investigated. There appeared a maximum rate of phenol conversion and TOC conversion as the catalyst loading increased. With phenol concentrations in the range of 400-2500 mg/L and oxygen pressure of 0.5 or 1.0 MPa, the optimal catalyst loading was 1.0 g/L, while it was 2.0 g/L at an oxygen pressure of 1.5 MPa. With a phenol concentration of 5000 mg/L, the optimal loading was 2.0 g/L for all oxygen pressures tested. Catalyst loading influences the reaction via the free-radical chain reaction involved in the catalytic wet air oxidation of phenol. Regarding oxygen pressures, at a phenol concentration of 400mg/L, the influence of the tested pressures (0.5, 1.0 and 1.5 MPa) on the 3h conversion of phenol was negligible, while the effect was significant for higher concentrations of phenol. The effect of oxygen pressure on TOC conversion was more profound, especially at a higher phenol concentration. At a pressure of 0.5 MPa, except for concentration of 400mg/L, the CO(2) selectivity barely exceed 80% at best, and was less than 25% with a phenol concentration of 5000 mg/L. At a pressure of 1.5 MPa, the selectivity was as high as 90% even for a concentration of 5000 mg/L. As was expected, increase of reaction temperature shortened the time taken to reach 50% phenol conversion. In addition, TOC conversion also increased with reaction temperature. Working from these observed results, optimal operating conditions were proposed.     

A novel two-layer compact electromagnetic bandgap (EBG) structure and its applications in microwave circuits

Recently, photonic bandgap (PBG) structures have become one of the most interesting areas of research. These structures consist of one-, two- or three-dimensional finite periodically perforated dielectric/metallic material or ground planes that forbid the propagation of all electromagnetic waves within a particular frequency band (called the bandgap). This property permits additional control over the behaviour of electromagnetic waves. The research work was originally done in optical region, …     

Improving the quality of fresh‐cut pineapples with ascorbic acid/sucrose pretreatment and modified atmosphere packaging

The effects of pretreatment and modified atmosphere packaging (MAP) on the quality of fresh‐cut pineapples stored at 4°C were evaluated for 7 days. The pretreatment was conducted by immersing the pineapple slices in a solution containing 0.25% ascorbic acid and 10% sucrose for 2min. MAP contained 4% oxygen, 10% carbon dioxide and 86% nitrogen. Both the pretreatment and MAP could reduce the respiration rate, ethylene production, textural and colour deteriorations, as well as the overall sensory deterioration in fresh‐cut pineapples. MAP could restrain the growth of microbes, but the pretreatment showed little effect. Fresh‐cut pineapples exhibited wet surface and off‐flavour after storage at 4°C for 3 days, while the pretreatment and MAP maintained the quality for up to 7 days. Copyright © 2007 John Wiley & Sons, Ltd.     

Decoupling the Direct and Indirect Biological Effects of ZnO Nanoparticles Using a Communicative Dual Cell‐Type Tissue Construct

While matter at the nanoscale can be manipulated, the knowledge of the interactions between these nanoproducts and the biological systems remained relatively laggard. Current nanobiology study is rooted on in vitro study using conventional 2D cell culture model. A typical study employs monolayer cell culture that simplifies the real context of which to measure any nanomaterial effect; unfortunately, this simplification also demonstrated the limitations of 2D cell culture in predicting the actual biological response of some tissues. In fact, some of the characteristics of tissue such as spatial arrangement of cells and cell–cell interaction, which are simplified in 2D cell culture model, play important roles in how cells respond to a stimulus. To more accurately recapitulate the features and microenvironment of tissue for nanotoxicity assessments, an improved organotypic‐like in vitro multicell culture system to mimic the kidney endoepithelial bilayer is introduced. Results showed that important nano‐related parameters such as the diffusion, direct and indirect toxic effects of ZnO nanoparticles can be studied by combining this endoepithelial bilayer tissue model and traditional monolayer culture setting.     

Mura‐type effect on human‐vision inspection

Abstract— Currently, the image quality of LCDs is examined subjectively by humans. There are no consistent rules for examining Mura, so it is necessary to develop an acceptable Mura standard between users and manufacturers. A Mura simulation experiment can establish the relationship between human visual perception and Mura phenomenon. The present study used several types and sizes of real Mura and subjects with different experiences to develop a starting point for examining Mura by the systematical approach of human factors. The objective in this study is to search the relationships between Mura characteristics and visual contrast thresholds. From the experimental results, Mura type, Mura size, and Mura location were the most important factors in the visual contrast threshold. A domestic Just Noticeable Difference model of the LCD industry was also constructed that could be used as an inspection criterion for LCD industry.     

A continuous ultrasound‐assisted packed‐bed bioreactor for the lipase‐catalyzed synthesis of caffeic acid phenethyl ester

BACKGROUND: The focus of this paper is the ultrasound‐assisted synthesis of caffeic acid phenethyl ester (CAPE) from caffeic acid and phenyl ethanol in a continuous packed‐bed bioreactor. Immobilized Novozym^® 435 (from Candida antarctica) is used as the catalyst. A three‐level–three‐factor Box–Behnken design and a response surface methodology (RSM) are employed to evaluate the effects of temperature, flow rate, and ultrasonic power on the percentage molar conversion of CAPE. RESULTS: Based on ridge max analysis, it is concluded that the optimum condition for synthesis is reaction temperature 72.66 °C, flow rate 0.046 mL min^?1, and ultrasonic power 1.64 W cm^?2. The expected molar conversion value is 97.84%. An experiment performed under these optimal conditions resulted in a molar conversion of 92.11 ± 0.75%. The enzyme in the bioreactor was found to be stable for at least 6 days. CONCLUSIONS: The lipase‐catalyzed synthesis of CAPE by an ultrasound‐assisted packed‐bed bioreactor uses mild reaction conditions. Enzymatic synthesis of CAPE is suitable for use in the nutraceutical and food production industries. Copyright © 2011 Society of Chemical Industry     

Synthesis of poly(lactic acid)‐based polyurethanes

Poly(lactic acid) (PLA) is a biodegradable aliphatic polyester, but its brittleness makes it unsuitable for many packaging and appliance applications. The goal of the work reported was to create novel poly(ester urethane)s that incorporate biodegradable poly(lactic acid) diols (PLA‐OHs) and good mechanical properties of increased molecular weight via crosslinked network formation for engineering plastics applications. Three kinds of polyols (PLA‐OHs, PLA‐OHs/poly(tetramethylene ether) glycol or PLA‐OHs/poly(butylene adipate) glycol (PBA)) and two kinds of diisocyanates (4,4‐diphenylmethane diisocyanate (MDI) or toluene 2,4‐diisocyanate (TDI)) were chosen for the soft and hard segments to compare their mechanical properties. In addition, 1,4‐butanediol and trimethylolpropane were each used as chain extender agents. Results showed the PLA/PBA‐polyurethanes (PLA/PBA‐PUs) of the MDI series and the PLA/PBA‐PUs of the TDI series had improved thermal stability and enhanced mechanical properties. Degradation behavior showed the PLA‐based polyurethanes could be degraded in phosphate‐buffered saline solution and enzyme solution. © 2012 Society of Chemical Industry     

Enhanced Emission of (In,Ga) Nitride Nanowires Embedded with Self‐Assembled Quantum Dots

We report the structure and emission properties of ternary (In,Ga)N nanowires (NWs) embedded with self‐assembled quantum dots (SAQDs). InGaN NWs are fabricated by the reaction of In, Ga and NH₃ via a vapor–liquid–solid (VLS) mechanism, using Au as the catalyst. By simply varying the growth temperature, In‐rich or Ga‐rich ternary NWs have been produced. X‐ray diffraction, Raman studies and transmission electron microscopy reveal a phase‐separated microstructure wherein the isovalent heteroatoms are self‐aggregated, forming SAQDs embedded in NWs. The SAQDs are observed to dominate the emission behavior of both In‐rich and Ga‐rich NWs. Temperature‐dependent photoluminescence (PL) measurements indicate relaxation of excited electrons from the matrix of the Ga‐rich NWs to their embedded SAQDs. A multi‐level band schema is proposed for the case of In‐rich NWs, which showed an anomalous enhancement in the PL peak intensity with increasing temperature accompanies with red shift in its peak position.     

EFFECTS OF HEXASULFOBUTYLATED C60 ON THE GASTRIC CIRCULAR MUSCLE OF GUINEA PIG

The effects of hexasulfobutylated (FC₄S), the fullerene derivative on the contraction of smooth muscle were tested pharmacologically on the circular muscle of stomach of guinea pigs. The effects of monomalonic acid C₆₀ (MMA C₆₀) on the same preparations were compared. The effects of those compounds on the taenia coli, portal vein and vas deferens of guinea pigs were also tested. The FC₄S did, while MMA C₆₀ did not elicit contracture of the circular muscle of stomach and taenia coli. Both FC₄S and MMA C₆₀ did not elicit contraction on the portal vein and on the vas deferens of the guinea pig. Prazosin (0.5 μM) or propranolol (0.5 μM) did not alter the FC₄S elicit contracture of the circular muscle of stomach. However, atropine (0.01, 0.1 and 1 μM), tetrodotoxin (0.1 μM) or low calcium medium decreased reversibly the FC₄S elicited contracture of the circular muscle of stomach. The effect of FC₄S on the contracture of the gastric muscles was also tested using various muscarinic receptor subtype antagonists. 4-DAMP (1 μM), muscarinic M3 receptor antagonist, and tropicamide (1 μM), muscarinic M4 receptor antagonist, did not alter the contracture elicited by FC₄S. Pirenzepine (0.1 μM), muscarinic M1 receptor antagonist, and methoctramine (0.25 μM), muscarinic M2 receptor antagonist, significantly decreased the FC₄S elicited contracture of the circular muscle. Atropine (1 μM) or tetrodotoxin (0.1 μM) completely blocked the FC₄S elicited contracture of the circular muscle of stomach. It is concluded that FC₄S elicited contracture of the circular muscle of stomach. The effect may be due to FC₄S acts on the cholinergic cells existed in the gastric muscle and indirectly activating the tetrodotoxin dependent releasing of the transmitters from the cells, then, activating the muscarinice M1, M2 receptors in the muscle eliciting the contractures.