AZ31 alloys were extruded by direct extrusion and bending-shear deformation (DEBS). The microstructure characteristic and texture evolution of DEBSed AZ31 sheets were investigated by electron backscattered diffraction (EBSD). It is found that DEBS technique could effectively refine grains and weaken texture. Besides, we also investigate how twinning affects dynamic recrystallization during hot extrusion. {10-12} extension twins can offer nucleation sites and enough energy to trigger dynamic recrystallization. Moreover, the character of direct extrusion and bending-shear die can lead to the activation of non-basal slip system and further dramatically weaken the basal texture of the microstructure with many preactivated basal slip systems.
In order to disscuss the ability of H2-production and wastewater treatment, a up-flow anaerobic sludge bed (UASB) using a synthesize substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, hydrogen producing rate, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. In this paper, UASB reactor was seeded with sludge from the Harbin Wenchang Sewage treatment plant dewatered sludge. Successful start-up of the reactor was achieved within 40 days at 35±1°C.The concentration of chemical oxygen demand (COD) in influent is increased from 1100mg/L . When it reached maximum, the loading rate was adjusted in a small way and indicators such as VFA, pH and COD in effluent as well as gas production are observed. The most relevant parameters were calibrated with lab-scale experimental data. These experimental results clearly showed that, the most proper corresponding organic loading rate (OLR) and hydraulic retention time (HRT) were 6 kg/ (m3.d)(COD=6000mg/L)and 24 h respectively. Up to 85% of COD was removed and the CH4 production rate of 3.2 m3 / (m3 .d) was obtained. The produced biogas contained 72% of CH4. In the mean time, anaerobic sludge multiplies more faster and exiguous particles appeared. Granules with diameter 1-3mm.
The isolation and identification of hydrogen production bacteria(HPB)with high yield and high evolution rate is an important foundation of fermented hydrogen production process by anaerobic digesting high strength organic wastewater. An improved Hungater rolling tubes technique and a plate method of culture bottle (PMCB) were employed to enumerate and isolate the anaerobes. The HPB-RL medium was designed specially for isolating and culturing anaerobic hydrogen bacteria. Culture temperature was at 37°C and 5.5 of pH. About 90 strains of bacteria were isolated, in which, a strain of the hydrogen producer with high yield and high evolution rate was isolated and named Rennanqi12. The isolates were straight rods, Grams positive, strictly anaerobic, no spore-forming bacteria, whole bacteria flagella, having capsule, 3~4 metachromatic granules. The strain of Rennanqi12 could produce hydrogen using molasses wastewater as the carbon resource. The isolate Rennanqi12 has the closest relationship with the strain C. cellulose for the 94% homology of 16S rDNA. The strain of Rennanqi12 might be a new species that belongs to a new genus. The amount of hydrogen-producing (YH2)is 1880.5ml/L medium and the maximum hydrogen-producing rate(QH2)is 28.2 mmol/g•(dry•cell)•h when R12 digested substrates were glucose.
This papre discussed the ability of H2-production and wastewater treatment, a continuous stirred tank reactor (CSTR)using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the pH value was 4.0~4.5, OLR was 24.5kg/(m3•d), oxidation-reduction potential was -350~-450mv, temperature was 34.0°C~36.0°C, hydraulic retention time was 6h~8h, the maximum yield of biogas production reached 20L/d and the maximum content of hydrogen is 70%. Detection of the end liquid product, ethanol and acetic acid are main, they are 70% ~90% of the total liquid product, so that is called ethanol-type fermentation.
The continuous flow stirred tank reactor (CSTR) is used for the experimental device. We discuss that the succession of climax community of the ecosystem according to composition of terminal liquid products and gas products, and the effect of the change of ‘causing factor’—organic loading rate(OLR) on the structure of microbial communities in the CSTR system, and the feedback regulation among the ‘following factors’( pH value, ORP value) and structure of microbial community. The community succession law restricted by OLR was studied from the angle of community dynamic: when OLR increases from 14 kg/m3•d to 20 kg/m3•d, the content of ethanol and acetic acid increased to about 60% ~ 80% of total terminal liquid products; hydrogen is started to product at the 18th day and stabilized at about 5 L/d gradually ,the maximum was 6.155L/d; the pH value and ORP value are 4.0~4.3 and -370~-400mv stable respectively, which indicated that ethanol-type fermentation microbial community replaced mixed acid fermentation microbial community.
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