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131.
A theoretical investigation on the effect of entrained air frequency response of hydraulic actuator controlled by open center three way spool valve is made. It is shown that entrainment of air gives rise to additional non-linearity into the system equation. Both nonlinear and linearized system equations, derived in dimensionless form, are solved numerically and analytically respectively. Increase of air content or decrease of area ratio in presence of air increases the resonant peak amplitude and decreases the resonant frequency leading to a reduction in bandwidth. Similar effect is observed also when the process of change of state of entrained air is adiabatic rather than isothermal. Entrainment of air also reduces the allowable open loop gain making the stability in the closed loop inferior. 相似文献
132.
The redox behavior of iron oxide modified with various amount of molybdenum (Mo) was investigated in the present study. The modified iron oxides were prepared by co-precipitation using urea hydrolysis method. The influence of Mo on the hydrogen production capacity and the material stability was studied in detail employing temperature-programmed reduction (TPR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET analysis. Furthermore, the activity and the stability of the samples were tested in repeated reduction and re-oxidation for 100 cycles with diluted H2 and H2O. The results indicate that Mo enhances the stability of iron oxide material by mitigating the sintering process. The positive influence of Mo in stabilizing the iron oxide material is attributed to the dispersion of Fe–Mo oxide material. The dispersion in turn inhibits the neck formation responsible for the sintering. 相似文献
133.
A simulated wastewater containing phenol (2500 mg/L), thiocyanate and ammonia-nitrogen (500 mg/L) was treated in an anaerobic (R1)-anoxic (R2)-aerobic (R3) moving bed biofilm reactor system at different hydraulic retention time (HRT) intervals (total HRT 3-8 days, R1: 1.5-4 days; R2: 0.75-2 days and R3: 0.75-2 days) and feed thiocyanate (SCN(-)) concentrations (110-600 mg/L) to determine substrate removal kinetics. In R1, phenol and COD reduction and specific methanogenic activity were inhibited due to the increase of SCN(-) in feed. Bhatia et al. model having inbuilt provision of process inhibition described the kinetics of COD and phenol utilization with maximum utilization rates of 0.398 day(-1) and 0.486 day(-1), respectively. In R2 and R3 modified Stover-Kincannon model was suitable to describe substrate utilization. In R2 respective maximum SCN(-), phenol, COD and NO(3)(-)-N utilization rates were 0.23, 5.28, 37.7 and 11.82 g/L day, respectively. In aerobic reactor R3, COD, SCN(-) and NH(4)(+)-N removal rates were, respectively, 10.53, 1.89, and 2.17 g/L day. The minimum total HRT of three-stage system was recommended as 4 days. 相似文献
134.
Kundu B Nandi SK Dasgupta S Datta S Mukherjee P Roy S Singh AK Mandal TK Das P Bhattacharya R Basu D 《Journal of materials science. Materials in medicine》2011,22(3):705-720
A systematic and extensive approach incorporating in vitro and in vivo experimentation to treat chronic osteomyelitis in animal model were made using antibiotic loaded special bioactive glass porous scaffolds. After thorough characterization for porosity, distribution, surface charge, a novel drug composite were infiltrated by using vacuum infiltration and freeze-drying method which was subsequently analyzed by SEM-EDAX and studied for in vitro drug elution in PBS and SBF. Osteomyelitis in rabbit was induced by inoculation of Staphylococcus aureus and optimum drug-scaffold were checked for its efficacy over control and parenteral treated animals in terms of histopathology, radiology, in vivo drug concentration in bone and serum and implant-bone interface by SEM. It was optimized that 60P samples with 60-65% porosity (bimodal distribution of macro- to micropore) with average pore size ~60 μm and higher interconnectivity, moderately high antibiotic adsorption efficiency (~49%) was ideal. Results after 42 days showed antibiotic released higher than MIC against S. aureus compared to parenteral treatment (2 injections a day for 6 weeks). In vivo drug pharmacokinetics and SEM on bone-defect interface proved superiority of CFS loaded porous bioactive glass implants over parenteral group based on infection eradication and new bone formation. 相似文献
135.
136.
Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash 总被引:1,自引:0,他引:1
Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m−3 d−1). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (Umax) and saturation value constant (KB) were found to be 2 kg m−3 d−1 and 1.69 kg m−3 d−1 respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor. 相似文献
137.
A continuum approach is presented to obtain the transverse vibration of trussed bridges traversed by a single moving load. The efficiency and the accuracy of the method are determined by comparing its results with those obtained by the dynamic analysis of the bridge as a discrete lumped mass system, which can account for both truss action and flexural action of the deck in the response. Using the proposed method, a parametric study is performed to show the influence of some important parameters on the dynamic response of the bridge. The parameters include relative stiffness of the bridge deck and truss, number of panels, type of truss and speed parameter. 相似文献
138.
139.
140.
P K Pujari T Datta Satya Prakash S B Manohar I K Gopalakrishnan G M Phatak J V Yakhmi PVPSS Sastry R M Iyer 《Bulletin of Materials Science》1991,14(3):681-686
Doppler-broadened annihilation radiation spectra have been measured as a function of temperature from 77 K to 300 K, for several
high temperature oxide superconductors viz single-phase YBCO, single- and mixed-phase Tl-Ca-Ba-Cu-O and Bi-Ca-Sr-Cu-O compounds.
The temperature-dependent parameters extracted respond to a change at the onset of superconducting transition. The observations
point to involvement of oxygen valence electrons at the onset of superconducting transition. Also a possible structural change
and/or increase in electron density at the oxygen vacancy/defect sites seem to accompany the transition. In addition, the
parameters derived are seen to be sensitive to the presence of more than one superconducting phases in mixed phase samples. 相似文献