Advanced Materials Research Vols. 347-353

Abstract: The Semi-Direct Injection (SDI) system has been shown to improve small engine efficiency and exhaust by utilizing a lean burn method. In order to better understand how to more readily utilize the control systems in SDI engine, the real-time operation of an SDI engine was modeled. A charging model was developed by using a filling-and-emptying model to simulate air exchange in an engine, including varying the intake manifold structure. A single-zone model was applied to a combustion model and the effects of air/fuel ratio and swirl ratio on combustion duration were also considered. The calculated results of the intake manifold pressure, heat release rate, and cylinder pressure were compared with the experimental data. The results of this study show that this modeling process approximates reality.

Abstract: Aqueous-phase reforming of 5 wt% ethylene glycol was studied at temperature of 498 K over Pt supported on Al2O3, SiO2, TiO2, CeO2. High selectivity about 90% for generation of hydrogen was observed over the supported Pt catalysts, suggesting that the methanation or the Fischer-Tropsch reactions involving CO/CO2 and H2 does not appear to be important over these catalysts under the present conditions. Compared with Pt/SiO2 and Pt/CeO2, Pt supported on Al2O3 and TiO2 produced measurable amounts of gaseous alkane that may be due to the acidity of the supports. To verify this suppose, the water-gas shift reaction was carried out over the catalysts under the same reaction conditions, and no CH4 was observed over these Pt catalysts. Relatively higher generation rates of hydrogen and carbon dioxide were achieved over Pt/Al2O3 and Pt/SiO2 catalysts.

Abstract: Competitive sorption capacity of equal concentration of Cs+ and Sr2+ in zeolite and palygorskite were studied by the intermittence method. zeolite and palygorskite of adsorbed Cs+ and Sr2+ were analysed with the XRD. They could offer some references for the sake of valuing mid-lower radwaste disposition. The results showed that adsorptive equilibrium time of NF to Cs+ and Sr2+ was about seven day, that of ZF was about three day, and that of CA was about fourteen day. Equilibrium adsorptive quantity of ZF to Cs+ and Sr2+ was the best, and that of NF was second, and that of CA was third. Sorption capacity of NF to Cs+ was the better than that to Sr2+, and selection of CA to Cs+ and Sr2+ was the little, and that of ZF was the lest. Equilibrium adsorptive rate of ZF to Sr2+ was almost the 100% and that of ZF to Cs+ was about 71.8% and that of NF to Cs+ was 66% and that of NF to Sr2+ was only 15% and that of CA to Sr2+ was about 28.6% and that of CA to Cs+ was only 16.4%. Crystal unit cell cubage and parameter a of zeolite and palygorskite adsorbed Cs+ and Sr2+ decreased and change of crystal unit cell parameter a、b and β of zeolite and palygorskite were ruleless.

Abstract: In this paper, simulates the air performance of multi-row finned-tube heat exchanger by Fluent. The mathematics model is established, using standard k-ε turbulence model. The temperature, velocity and pressure changes of air are analyzed. By research the multi-row finned-tube heat exchanger, analyzed the different structures have different effects on the efficiency of heat transfer, obtained the most appropriate number of tube rows, making the heat exchanger for maximum heat transfer efficiency.

Abstract: In order to provide the scientific and practical basis to the industrial test of methanol catalytic synthesis from cornstalk syngas, the systemic research about the reaction conditions of methanol catalytic synthesis over a domestic Cu-based catalyst C301 was carried out in a tubular-flow integral and isothermal reactor. The reaction temperature, the cornstalk syngas proportion and the entrance syngas flow rate were optimized under the reaction pressure of 5MPa and the credible results were obtained.

Abstract: After investigating the effects of each parameter on the esterification of FFA catalyzed by Amberlyst-15 in the trap grease, the optimal values were determined through an orthogonal experimental design. The optimum conditions for the esterification were determined to be 27:1 molar for the methanol to FFA in the trap grease, 95°C for the reaction temperature and 3 h for the reaction time. Stability of Amberlyst-15 was also studied under the optimal reaction conditions. The stability of the catalyst was not decreased much even after 10 times repeated use. The acid value was decreased from 100 mg KOH/g to 1.3 mg KOH/g in this process.

Abstract: Currently, ethanol has gained significance since it is substantially used as an alternative biofuel. It can be produced by agro-industrial residuals such as corncobs. In ethanol production, hemicellulose and lignin are inhibitors of the enzymatic hydrolysis between cellulase and cellulose. They must be removed during in the pretreatment stage. In this research H2SO4 and NaOH were used as pretreatment solution at high temperature. The temperature were varied for 120 to 170 °C. The result showed that the optimal pretreatment condition of corncobs was using 2% (v/v) NaOH for 24 hr digestion in 1% (v/v) H2SO4 and then heating at 170 °C for 5 min. At this condition, the cellulose content of corncobs increased from 66.52% (untreated) to 92.25% (pretreated). Enzyme digestion of pretreated corncobs at an optimum condition yielded the reducing sugar level of 8.74 g/L. The optimum conditions were achieved at cellulase loading of 10 FPU/g and digestion time of 4 hr. Finally, the reducing sugar solution of 5 g/L was fermented with Zymomonas mobilis TISTR405 at 30°C and pH 5.0 for 48 hr, yielding ethanol of 1.8 g/l or 35.93% of the theoretical ethanol yield.

Abstract: Malic enzymes are a class of oxidative decarboxylases which catalyze the oxidative decarboxylation of malate to pyruvate and carbon dioxide. the former studies on lipid pathways and genetic engineering test for enhanced lipid synthesis suggests that ME are the most promising targets gene for enhanced lipid synthesis. The full-length cDNA encoding NADP malic enzyme was obtained from oleaginous microalgae Dunaliella parva, which include 1293 bp open reading frame (ORF) and 26 bp 3′-untranslated sequence. NCBI-CD search revealed that there are two mainly domains predicted in the Dunaliella parva ME protein. In addition, a 724 bp promoter was obtained. The potential regulatory elements associated with hormone and light responses were also found in the ME promoter region. Similarity analysis revealed that the highest identity was found between Dunaliella parva and Chlamydomonas reinhardtii. The Dunaliella parva ME also showed wide similarity with other species.

Abstract: This study was to investigate the fermentation of rice straw using various microorganisms, i.e., the bacterium Zymomonas mobilis, a distillery yeast Saccharomyces cerevisiae and a co-culture of Zymomonas mobilis and Saccharomyces cerevisiae. Rice straw was pretreated with alkaline and followed by enzymatic hydrolysis using cellulase before fermentation by the bacterium and a distillery yeast. Results show that alkali pretreatment is appropriate for rice straw since this pretreatment condition can produce the maximum cellulose of 88.96% and reducing sugar content of 9.18 g/l. Furthermore, the ethanol yield after enzymatic hydrolysis (expressed as % theoretical yield) was 15.94-19.73% for the bacterium, 20.48-35.70% for yeast and 21.56-29.89% for co-culture. Therefore, the distillery yeast was a suitable microorganism for ethanol production from rice straw.

Abstract: The purpose of this study is to preparing high heat value fuels. In present investigation, sodium soap made from microalgae oil was used as the experimental material with significant molecular polarity, then by using microwave heating technology, which may preferentially activate the polar molecule and functional groups of the soap molecular, leading to the high selectivity of decarboxylation. The hydrocarbon content arrived maximum in 900W, when was investigated in different microwave radiation power, obtained pyrolysis liquid similar with high heat value fuel. The hydrocarbon content were usually above 70%. In addition, its density and dynamic viscosity are 0.845-0.870g/cm3 and 2.15-2.70mm2/s.