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21.
Kumar Rajneesh Goel Varun Kumar Anoop Khurana Sourabh Singh Paramvir Bopche Santosh B. 《Journal of Mechanical Science and Technology》2018,32(1):399-404
Journal of Mechanical Science and Technology - The Computational fluid dynamics (CFD) based analysis is carried out to investigate the thermal and hydraulic performance of circular rib roughened... 相似文献
22.
Goel R.K. 《中国矿业大学学报(英文版)》2014,(6)
A considerable amount of tunnelling has been going on in India for various projects such as hydroelectric power, irrigation, roads and railways. Most of these projects are located in Himalayas, far awa... 相似文献
23.
In the present work, we report the preparation of PLZT thin films in pure perovskite phase by RF magnetron sputtering without
external substrate heating and their integration with micro-cantilevers. The ‘lift-off’ process for patterning different layers
of a micro-cantilever including PLZT, Pt/Ti and Au/Cr was employed. The basic requirement of lift-off process is that the
deposition temperature should not exceed 200°C otherwise photoresist will burn out. Therefore, one of the aims of the present
work was to prepare PLZT film at lower deposition temperatures, which can be subsequently annealed to form pure perovskite
phase. This also strongly favours the incorporation of ‘lift-off’ process for patterning in the complete process flow. As
no external substrate heating was required in the deposition of PLZT film, this objective has been successfully accomplished
in the present work. The ‘lift-off’ process has been successfully adopted for patterning the composite layers of PLZT/Pt/Ti
and Au/Cr using thick positive photo-resist (STR-1045). Different types of cantilever beams incorporating PLZT films have
been successfully fabricated using ‘lift-off’ process and bulk micromachining technology. The proposed process can be advantageously
applied for the fabrication of various MEMS devices. 相似文献
24.
An experimental study was conducted under continuous flow conditions to evaluate some of the factors influencing contaminant removal by electrocoagulation (EC). A bench-scale simulation of drinking water treatment was done by adding a filtration column after a rectangular EC reactor. Contaminant removal efficiency was determined for voltages ranging from 10 to 25 V and a comparative study was done with distilled water and tap water for two contaminants: nitrate and arsenic(V). Maximum removal efficiency was 84% for nitrate at 25 V and 75% for arsenic(V) at 20 V. No significant difference in contaminant removal was observed in tap water versus distilled water. Increase in initial As(V) concentration from 1 ppm to 2 ppm resulted in a 10% increase in removal efficiency. Turbidity in the EC reactor effluent was 52 NTU and had to be filtered to achieve acceptable levels of final turbidity (5 NTU) at steady-state. The flow regime in the continuous flow reactor was also evaluated in a tracer study to determine whether it is a plug flow reactor (PFR) or constantly stirred tank reactor (CSTR) and the results show that this reactor was close to an ideal CSTR, i.e., it was fairly well-mixed. 相似文献
25.
Md. Irshad Irfan Ahmad Syed Jafar Mehdi Harish Chandra Goel 《International Journal of Food Properties》2013,16(1):179-186
The antioxidant capacity of commonly consumed cucurbits vegetable was determined by the DPPH, FRAP, Fe3+ reducing power, and hydrogen peroxide scavenging assay. The aqueous extract of Luffa cylindrica showed the highest value of phenolic content and antioxidant capacity based on FRAP, Fe3+ reducing power, and hydrogen peroxide scavenging assay. However, Laginaria siceraria extract showed the highest flavonoid and DPPH scavenging activities among all three cucurbits used in this study. Phenolic content in aqueous extracts of Luffa cylindrica and Laginaria siceraria was almost equal. Cucurbita maxima exhibited the lowest phenolic, flavonoid content, and exhibited the lowest power of antioxidant scavenging. The antioxidant capacity of cucurbits was significantly correlated (P < 0.05) with the phenolic content of their extracts. The antioxidant capacity of Luffa cylindrica and Laginaria siceraria have also shown a significant correlation (P < 0.05). 相似文献
26.
The Ferroelectric relaxor ternary system 0.5PZN-(0.5 – x)PFN-xBZN was prepared using the columbite precursor method. The stability of the perovskite phase was studied as a function of BZN content in the system. It was observed that BZN is a good stabilizer of perovskite phase because of the high value of electronegativity difference between its cation and anion. It has also been observed that addition of BZN increases the dielectric maxima peak value and decrease the Curie temperature of the ceramics. The ternary composition 0.5PZN-0.425PFN-0.075BZN has been identified for MLCs applications. It has a T
c of around room temperature with a peak dielectric constant 6400 and tan 0.05. The mechanical properties of relaxor materials have also been studied and reported. 相似文献
27.
A 29-year-old man was admitted to the hospital because of a high fever and dyspnea. He had a history of bronchial asthma and had had a bullectomy of the right lung at 15 years of age. He had visited a family physician because of fever and non productive coughing. Medications had no effect on his symptoms, and dyspnea developed. A chest X-ray film showed total collapse of the right lung, and he was referred to our hospital. Laboratory data showed eosinophilia and a high titer of IgE. Total obstruction of the right main stem bronchus by mucous plug was found during fiberoptic bronchoscopy. Aspergillus was detected by pathological examination of bronchial lavage fluid. Tests for aspergillus-specific IgE and IgG antibody were positive, as was immediate skin reactivity to Aspergillus. Allergic bronchopulmonary aspergillosis (ABPA) was diagnosed. Infusion and inhalation of a corticosteroid and fluconazole were effective; the symptoms resolved and X-ray findings improved. While migratory infiltration, proximal bronchiectasis and segmental or subsegmental atelectasis caused by a mucous plug are common X-ray findings in allergic bronchopulmonary aspergillosis, total collapse is rare. 相似文献
28.
This paper considers a two unit cold standby redundant system subject to a single repair facility with exponential failure and general repair time distribution. Each unit can work in three different modes — normal, partial failure and total failure. There is a perfect switch to operate the standby unit on total failure of the operative unit. The system has been analysed to determine the reliability parameters e.g. mean time to system failure (MTSF), steady state availability, mean recurrence to a state and expected number of visits to a state, first two moments of time in transient state, by using the theory of Semi-Markov Process. Howard's reward structure has been super-imposed on the Semi-Markov Process to obtained expected profit of the system. A number of results obtained earlier are derived as particular cases. 相似文献
29.
Stochastic models for hardware-software systems are developed and used to study their performance as a function of hardware-software failure and maintenance rates. Expressions are derived for the distribution of time to a specified number of software errors, system occupancy probabilities, system reliability, availability, and average availability. The behavior of these measures is investigated via numerical examples. 相似文献
30.
This paper investigates the mathematical model of a system composed of (m + 1) non identical units—one functioning and m standby. Each unit of the system has three possible states—normal, degraded and failed. We consider two types of repair facilities—overhaul and minor repair. The system breaks down when the (m + 1)th unit after total failure is finally rejected and no standby remains to replace it. Several reliability characteristics of interest to system designers as well as operations managers have been computed. Results obtained earlier are verified as particular cases. 相似文献