Advanced Materials Research Vols. 383-390

Abstract: In this work hydroxyapatite coating through Sol-Gel method on stainless steel 316 L was investigated. Biocompatible additives such as P₂O₅, Na₂CO₃, KH₂PO₄ and HA commercial powder were used for preparation of hydroxyapatite Sol-Gel. Corrosion behavior of the ground and passivated stainless steel was evaluated. Characterization of the coated samples was performed by using SEM and XRD. The results showed that by increasing the sintering temperature, a denser structure of hydroxyapatite was obtained, and volume fraction and size of porosities decreased. Thick hydroxyapatite coatings with a thickness range of 50-70 µm free from cracks were obtained.

Abstract: This paper analyses the effect of protective coatings on the oxidation behavior of 6061Al/SiC composite material at temperatures ranging from 500 to 800 K. Aluminum and AlCrN coatings are employed as protective coatings in order to improve the oxidation resistance of the composite. SEM, EDAX, XRD and oxidation measurement techniques are used to study the oxidation behavior and to characterize the composite specimens. Oxidation of the composite material without protective coatings is seen to be very rapid during the initial stages of exposure to the high temperatures but subsequently slowed down due to the formation of a protective surface layer of oxide. The oxidation was especially severe above 600 K. The interface between the matrix and reinforcement particles and the grain boundary regions of intermetallic precipitates in the matrix enhance this oxidation process since they provided sites for oxidation initiation. Aluminum coating on the composite obtained by DC magnetron sputtering technique and AlCrN coating obtained by low voltage electron beam evaporation technique reduce the oxidation rate effectively since the interface regions between the matrix and reinforcement, grain boundary regions of the matrix are unexposed to the atmosphere. Aluminum coating provides better oxidation resistance for 6061 Al/SiC composites.

Abstract: Strip casting process is possible to shorten for producing strip. Strip is produced from molten metal continuously and directly by strip casting process. Melt drag process is one of the single roll strip casting process. Melt drag process is simpler than general twin roll strip casting process. One of defect of cast strip is surface conditions, for example surface roughness. Cast strip surface roughness is larger than hot rolled strip. Large strip surface roughness is negative effect for cold rolling after strip casting or hot rolling. The aim of this study is improvement of cast strip surface roughness by melt drag process. We suggested vertical melt drag process. And investigations were operated such us producing conditions of Al-Si alloy strip, surface roughness of cast strip and microstructures.

Abstract: In this paper, a numerical simulation was performed to investigate heat transferring characteristics on the leading edge of a blade with three rows of holes of film-cooling using Realizable k- model. Three rows of holes were located on the suction side leading edge stagnation line and the pressure surface. The difference of the cooling efficiency and the heat transfer of the three rows of holes on the suction side and pressure side were analyzed; the heat transfer and film cooling effectiveness distribution in the region of leading edge are expounded under different momentum rations.The results show that under the same condition, the cooling effectiveness on the pressure side is more obvious than the suction side, but the heat transfer is better on the suction side than the pressure side. The stronger momentum rations are more effective cooling than the heat transfer system.

Abstract: The biosorption of neutral red, from aqueous solutions by Penicilium sp. biomass was studied in a batch system with respect to pretreatment methods, contact time, pH, initial dye concentration and temperature. The NaHCO₃- treated biomass exhibited maximum dye uptake at pH 5-6. A larger amount of dye was removed by the pretreated biomass in the first 10 min of contact time and the equilibrium was established in 60 min for 50 mg/L of initial dye concentration. The optimum biosorption temperature was determined as 40 °C. Biosorption played main role in dye removal from aqueous solution in this study. The results indicate that the pretreated Penicilium sp. biomass can be used as an effective biosorbent to remove neutral red from aqueous solution.

Abstract: The stainless steel is more and more applications to the medical field; the most is the austenitic stainless steel. In this paper, 00Cr₁₈Ni₁₄Mo₃ mechanical properties of austenitic stainless steel screw, compared to the solution of the former and the sample microstructure after solution treatment, energy spectrum and the torque angle reverse faults, compared to solution treatment found that mechanical properties of the samples after meet the standard can be applied to practice.

Abstract: At present, biological data provide possibility to further data analysis data, improving deep understanding on complicated regulatory model. Thanks to the study of model organism yeast and the construction of its gene regulatory network, we can improve the diagnosis and treatment level of the human polygene hereditary diseases which are similar to yeast genes. Among a variety of gene regulatory network models, the one constructed by Bayesian Network corresponds to Biology's reality most. So we choose Bayesian Network to construct yeast gene regulatory network, of which process involves Bayesian Network structure learning and parameter learning. We gather and integrate the yeast data, by which we determine the network nodes. We learn the structure using MMHC algorithm, and use the simulated annealing algorithm to rating search so that we can get the best solution. Finally we use Bayesian algorithm or MLE algorithm to learn and determine the parameter. With the help of this regulatory network, researchers are able to have more acquaintance with the complex regulatory relationships in the gene regulatory network.

Abstract: The conditions for cellulase production were studied with the mixed germs of Aspergillus niger (A.niger) and Trichoderma viride (R.viride) using straw stalk powder as carbon recourse by solid-state fermentation (SSF). The conditions of the mixed strains SSF were optimized by single factor experiments and orthogonal experiments in four aspects: the inoculation ratio, the bran-straw mass ratio, fermentation time and the filled volume. The optimal SSF conditions of the mixed strains were as follows: inoculation ratio of R.viride to A.niger was 1, the bran-straw mass ratio was 0.3, the time of fermentation was four days and the filled volume is 100 mL /1000 mL. The enzyme activity of FPA, CMC and β-glucosidase are 5.29 IU/mL, 9.33 IU/mL and 49.91 IU/mL in the optimal cultivation condition, which were 2.28~2.47 times, 2.39~2.45 times, 1.38~2.09 times as high as single-germ fermentation, respectively. The enzyme activity of cellulose from the mixed fermentation was higher than that from the fermentation of single bacteria.

Abstract: Removal of hydrogen sulfide from waste and energy-rich gases is required not only because of environmental health and safety reasons, but also because of operational reasons. Biotrickling filter is one of the most promising clean technologies for removing H₂S. This study attempted to remove H₂S in biogas using a laboratory-scale biotrickling filter. The performance and the influence caused by different concentrations of pH, CODCr, sulfate, external nitrate source in the nutrient solution were systematically analyzed. Optimal operating conditions were obtained by the following: pH 2.0~8.0, COD 400~500mg/L, cumulative sulfate concentration 250mg/L, external nitrogen concentration 7.5mg /L.

Abstract: For making Eco-Friendly cellulose sponge, cellulose pulp dissolving properties were researched in this paper. NaOH and NaOH/Urea solutions were both used, various factors (temperature, concentration and time) on viscosity of the pulp were studied. At first, ten different kinds of cellulose pulps were dissolved at low temperature in a certain range of concentration of NaOH solvent and the pulp with best soluble property was chosen. On the above basis, effects of the temperature of alkaline solvent and concentration on the viscosity of the selected pulp was fatherly experimented and analyzed. The result was got that at concentration of 8% of NaOH solution and at temperature of -5°C, the cellulose pulp has the best solubility. In the meantime, the solution has the biggest viscosity. On the other hand, NaOH/Urea solvent was tested for cellulose solubility. After experiment, the tests showed that when NaOH/Urea blending ratio is 8:12, the selected pulp solves completely and the solution was clear. Thus NaOH/Urea solvent has better solubility than that of NaOH solution for solving the cellulose pulp.