Advanced Materials Research Vols. 233-235

Abstract: The conventional process for isobornyl acetate synthesis from camphene and acetic acid is a batch process. The purpose of this paper is to synthesize isobornyl acetate in continuous process in a fixed bed reactor. The continuous reaction conditions were studied. The experiment was put into practice under the following conditions: 35-45, camphene/acetic acid feed ratio(wt%) from 1 to 2 and space velocity from 0.6 to 1.8 h^-1. A kinetic model was developed which describes the experimental data well. A pilot fixed reactor was simulated by using the kinetic model.

Abstract: By using combustion synthesis under high gravity, TiC-TiB₂ fine-grained composite ceramics with hypoeutectic, eutectic and hypereutectic microstructures were prepared through rapid solidification. XRD, FESEM and EDS results show that with increasing TiB₂ content, TiC-TiB₂ composite ceramics transform the microstructures consisting of fine TiB₂ platelets from ones composed of fine TiC spherical grains, whereas when TiB₂ content reaches 50mol%, the ceramics develop the eutectic microstructures that small aspect-ratio TiB₂ platelets were embedded in TiC matrix. Mechanical properties show that relative density, Vickers hardness and flexural strength of TiC-50mol%TiB₂ all reach the maximum values (respectively as 98.6 % ,18.4 GPa, 840 MPa) due to eutectic reaction during solidification, meanwhile TiC-50mol%TiB₂ has the maximum fracture toughness of 11.5 MPa∙m^0.5 due to the cooperative action of crack deflection, crack-bridging and pull-out toughening by fine TiB₂ platelets.

Abstract: In this study, the ethyl ester of EPA and DHA was produced, using the soapstock (soap lye and solid lipid) of fish oil as the raw material through acid catalysis and alkali catalysis, whose optimal conditions were investigated. It was obtained that the optimal conditions for acid catalysis (a) and alkali catalysis (b) were as follows: (a) refluxing for 4h at normal atmosphere, 80, phosphoric acid, 3%, [w/w], alcohol, 65%, [v/v]; (b) sodium hydroxide, 1% [w/w], alcohol, 40% [v/v], 50for 2-6h in the stirred autoclave. Under the optimal conditions, a conversion ratio of ethyl ester fish oil of 96.8% (a) and 97.4% (b) were obtained. The concentration of EPA and DHA was enhanced from 30% to 60.7% through three class molecular distillation method. This n-3 polyunsaturated fatty acid-enriched fish oil may be a valuable supplement in the green feed.

Abstract: The mechanical properties of Low Carbon Si-Mn Q&P steel are strongly affected by the conditions of heat treatment. Microstructures and mechanical properties of Low Carbon Si-Mn Q&P steel at different partitioning temperature and holding time was investigated. The microstructure was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that the microstructure of Q&P steel is carbon-depleted lath martensite and carbon enriched retained austenite. The retained austenite appear film-type between the laths. Higher partitioning temperature and longer partitioning time can obtain more retained austenite. It is shown that with increasing partitioning time ultimate tensile strength decreases, while elongation increases obviously. Carbon-enriched metastable retained austenite is considered beneficial because the TRIP phenomenon during deformation can contribute to formability and energy absorption.

Abstract: A chitinase was purified from the culture supernatant of Bacillus licheniformis with Auricularia auricular colloidal substance as the sole carbon source. The optimized conditions of this species strain for the production of chitinases were found to be when the culture was shaken at 37°C for 3 days in medium (pH 7) containing 0.05% KH₂PO₄, 0.5%NaNO₃, 0.05% MgSO₄·7H₂O and 1.5% Auricularia auricular colloidal substance powder(w/v). The molecular weights of the chitinases determined by SDS-PAGE were approximately 52kDa. The chitinases was inhibited highly by Mg²⁺ and PMSF, whereas Co²⁺ and Mn²⁺ could increase highly the activity of the chitinase.

Abstract: The dynamic-static method is used for study on the formation of the biofilm on pipe surface and the relationship between the biofilm and the induction time of the biofouling. The biofilm of slime forming bacteria on the surface of the copper electrodes is characterized by Electrochemical Impedance Spectroscopy (EIS) on the static experimental apparatus. Meanwhile, the induction period of biofouling is detected by Biofouling Dynamic Simulation System (BDSS). The experimental results, which associate with the biofouling resistance by the time, are shown that the maximum value of the biofilm thickness calculated is about 3.5μm by the electrochemical parameters fitted by the compute. These can indicate that the static biofilms measured has a strict correspondence with the dynamic biofouling resistance, which is a new method for studying on the mechanism of biofouling.

Abstract: 4-aryl-3,4-dihydropyrimidin-2(1H)-ones were synthesized by using Biginelli reaction in iconic liguids. The simple method provoids the title compounds in 67~97% yields by the reaction of aromaic aldehydes with aectoacetrate and urea in the presence of iconic liquids as solvent and katalyst. This method was found to be efficient way for the synthesis of 4-aryl-3,4-dihydropyrimidin-2(1H)-ones.

Abstract: With catalysis system, carbonylation of methanol liquid is a better method in manufacture of acetic acid. However previous control mode can not well meet technique demands. This paper made some modification on reaction process control based on manufacturing technique. Aimed at much influence upon temperature including uncertainty, cross coupling effects and big delay about model, predictive functional control (PFC) technique combined with PID and feedforward are applied to temperature control of reaction process through supervisory total distributed control which leads to the improvement of regulatory capacity for both reference input tracking and load disturbance rejection. Practical results show stable and reliable system operation.

Abstract: This study used nickel wire to trap the magnetotactic bacteria which had adsorbed Au(III), and a magnetic separation model was built to describe this process. Kinetics of the movement of metal loaded bacteria in the whole magnetic field was investigated both experimentally and theoretically. It was found that the magnetic intensity had evident effect on the separation efficiency, but little effect on the separation rate. The period of trapping bacteria to capacity for the nickel wire was proved about 100 minutes. It was found that the trapped bacteria were deposited in multi-layers, showing the ability of multi-layer trapping for the wires. The theoretical results could reach a good agreement with the experimental, which indicated the feasibility of applying the model to the optimization of magnetic separation process using magnetotactic bacterium.

Abstract: A novel method of cellulose degradation is investigated in this paper. In this work, a three-electrode system, which contains a Pb/PbO₂ anode, two copper cathodes and a reference saturated calomel electrode (SCE), is applied to electrocatalytic degradation of cellulose. The composition of the products in filtrate is characterized by phenol-sulfuric acid method, NMR and GC-MS. In addition, the solid sample is analyzed via Ubbelohde capillary viscometer and FT-IR spectra. The results suggest that it is effective to convert cellulose to soluble sugar, 5-hydroxymethylfurfural (5-HMF) and other products by electrocatalytic method. The reaction mechanism of cellulose degradation is also discussed.