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Design and Modeling of a Capacitor Bank Power Supply for Fast Charging
Surender Kumar Sharma,Pankaj Deb,R. Shukla,P. Banerjee,T. Prabaharan,R. Das,B. Das,B. Adhikary,A. Shyam 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61
Power supplies used in pulsed power applications are rugged, and the capacitor bank charges rapidly. The capacitor bank is fully charged to the rated voltage in a minimum time so as to reduce the dielectric stress on the capacitors and to increase their life. When the capacitor bank is discharged in the load much Electromagnetic Interference (EMI) and Electromagnetic Pulse (EMP) due to high currents discharges is generated, which can damage the electronic circuitry in the power supply if proper shielding & isolation are not provided to it. We have designed and fabricated a compact, rugged and low-cost high voltage (HV) power supply for a 114-kJ, 40-kV capacitor bank. The power supply consists of a high voltage transformer (5.25 kVA, 230 V/35 kV, 50 Hz), a high voltage diode (Semikron Make PIV 110 kV, 150 mA) and a charging resistor placed in a tank filled with oil. The charging resistors value is selected after a PSPICE simulation of the charging circuit for different values of the charging resistor. The charging current is limited with the selected resistor so that it does not exceed the current limit of the HV transformer & diode. The input voltage to the high voltage transformer is given through autotransformer, which rotates from 0 ?230 volts in 40 sec with a single-phase synchronous motor. The capacitor bank is charged to 40 kV in a minute after that, the power supply is decoupled from the capacitor bank by using a pneumatic decoupling switch, then the capacitor bank's switch is triggered to deliver the capacitor bank's energy to the load. Control and protection in the power supply is provided for its safe operation. The monitoring of charging voltage is done with a digital display meter with fiber optic isolation by using a V-F and then F-V converter in order to provide electrical isolation.
Radioprotective and Antioxidant Activity of Fractionated Extracts of Berries of Hippophae rhamnoides
Rakesh Kumar Sharma,Raman Chawla,Rajesh Arora,Shikha Singh,Ravinder Kumar Sagar,Raj Kumar,Ashok Sharma,Manju L. Gupta,Surender Singh,Jagdish Prasad,Haider A. Khan,Anand Swaroop,A.K. Sinha,A.K. Gupta,R 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1
Plants are an abundant source of medicinal compounds, some of which are useful in combating free radical-1002 (flavonoid-poor fraction) of Hippophae rhamnoideswere screened on the basis of their reducing power in the aqueousphase. REC-1001 was selected for further study, since it exhibited 27.38 times higher antioxidant activity than REC-1002.REC-1001 also showed significant (P. .05) membrane protection potential at 50 .g/mL, which was attributed to its abilityto scavenge peroxyl radicals (64.82. 1.25% scavenging within 1,440 min). A significant (P. .05) difference of 67.02% infree radical scavenging activity at 1,000 ng/mL between REC-1001 and vitamin E demonstrated the extract fraction’s worthc-tion. Further, REC-1001 was found to be nontoxic up to 200 mg/kg of body weight. This research suggests that the REC-1001 fraction of H. rhamnoidesextract is a safe and effective antioxidant nutraceutical product.
( Kumar Pranaw ),( Surender Singh ),( Debjani Dutta ),( Nirpendra Singh ),( Garima Sharma ),( Sudershan Ganguly ),( Vinay Kalia ),( Lata Nain ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.11
Proteases produced by Xenorhabdus are known to play a significant role in virulence leading to insect mortality. The present study was undertaken to purify and characterize protease from Xenorhabdus indica, an endosymbiont of nematode Steinernema thermophilum, and to decipher its role in insect mortality and its efficacy to control Helicoverpa armigera. A set of 10 strains of Xenorhabdus isolated from different regions of India were screened for protease activity on the basis of zone of clearing on gelatin agar plates. One potent strain of Xenorhabdus indica was selected for the production of protease, and the highest production (1,552 U/ml) was observed at 15-18 h of incubation at 28oC in soya casein digest broth. The extracellular protease was purified from culture supernatant using ammonium sulfate precipitation and ion-exchange chromatography. The enzyme was further characterized by SDS-PAGE and zymography, which confirmed the purity of the protein and its molecular mass was found to be ~52 kDa. Further MALDI-TOF/TOF analysis and effect of metal chelating agent 1,10-phenanthrolin study revealed the nature of the purified protease as a secreted alkaline metalloprotease. The bioefficacy of the purified protease was also tested against cotton bollworm (Helicoverpa armigera) and resulted in 67.9 ± 0.64% mortality within one week. This purified protease has the potential to be developed as a natural insecticidal agent against a broad range of agriculturally important insects.
Anamika Sharma,Vikrant Nain,Rameshwar Tiwari,Surender Singh,Anurup Adak,Pawan Kumar Singh Nain,Lata Nain 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.3
The present investigation was aimed towards pretreatment optimization of corncob to maximize cellulose and hemicellulose recovery, followed by substrate selection for holocellulase production using psychrotolerant Aspergillus niger SH3. Dilute alkali pretreatment (1.5% NaOH) resulted in higher recovery of cellulose (59.66%) and hemicellulose (28.34%) from corncob, while corn stover proved to be the best substrate for holocellulase production. Further, saccharification was optimized by Box-Behnken design to select the suitable conditions for maximum sugar release from pretreated corncob. The optimum conditions for maximum sugar release were 8% (w/v) substrate loading, 11 FPU/gds enzyme loading at temperature 38 oC and pH 3.0 which resulted in 114.5% higher sugar yield (912mg/gds of pretreated biomass) as compared with un-optimized conditions (425.35mg/gds). Theoretical yield of 48.8% ethanol was achieved through simultaneous saccharification and fermentation (SSF) using pretreated corncob. This study illustrates the potential of different corn residues as a promising substrate for bioethanol production.
Strength and durability characteristics of bricks made using coal bottom and coal fly ash
Ashish, Deepankar Kumar,Verma, Surender Kumar,Singh, Joginder,Sharma, Namesh Techno-Press 2018 Advances in concrete construction Vol.6 No.4
The study evaluates properties of brick having coal ash and explores the possibility of utilization of coal bottom ash and coal fly ash as an alternative raw material in the production of coal ash bricks. Lower cement content was used in the investigations to attain appropriate strength and prohibit high carbon content that is cause of environmental pollution. The samples use up to 7% of cement whereas sand was replaced with bottom ash. Bricks were tested for compressive strength, modulus of rupture, ultrasonic pulse velocity (UPV), water absorption and durability. The results showed mix proportions of bottom ash, fly ash and cement as 1:1:0.15 i.e., M-15 achieved optimum values. The coal ash bricks were well bonded with mortar and could be feasible alternative to conventional bricks thus can contribute towards sustainable development.
Facile synthesis and electrochemical investigations of Tin‑doped MnO2/ carbon nanotube composites
Indu Kaushal,Ashok K. Sharma,Priya Saharan,Vinit Kumar,Surender Duhan 한국탄소학회 2019 Carbon Letters Vol.29 No.1
The composites of carbon nanotube (CNT) supported by Sn-doped MnO2 with enhanced capacitance have been fabricated with varying dopant concentrations. The composites have been subjected to physiochemical, configurational, and morphological analyses by FTIR, UV–Vis spectroscopy, X-ray diffraction and field emission scanning electron microscopy, high resolution transmission electron microscopy and selected area electron diffraction studies. The electrochemical performance of the composite has been evaluated by cyclic voltammetry and charge/discharge techniques. Highest specific capacitances of 940 F g−1 at a current density of 0.35 A g−1 and 927 F g−1 at 5 mV s−1 in 1 M Na2SO4 electrolyte solution was achieved in the case of 5% Sn doped composite. Moreover, the electrode demonstrated good cycling performance and retaining 79.7% of the initial capacitance over 3000 cycles. The superior electrochemical performance is accredited mainly to the porous sheath hierarchical architecture, which consist of inter connected MnO2 nanoneedles uniformly coated over the CNT surface. This peculiar architecture is responsible for fast ion/electron transfer and easy access of the active material.
Properties of concrete incorporating sand and cement with waste marble powder
Ashish, Deepankar K.,Verma, Surender K.,Kumar, Ravi,Sharma, Nitisha Techno-Press 2016 Advances in concrete construction Vol.4 No.2
Marble is a metamorphic rock used widely in construction which increases amount of marble powder obtained from it. Marble powder is a waste product obtained from marble during its processing. Marble waste is high in calcium oxide content which is cementing property but it creates many environmental hazards too if left in environment or in water. In this research, partial replacement of cement and sand by waste marble powder (WMP) has been investigated. Seven concrete mixtures were prepared for this investigation by partially replacing cement, sand with WMP at proportions of 0%, 10% and 15% by weight separately and in combined form. To determine compressive strength, flexural strength and split tensile strength of concrete made with waste marble powder, the samples at the curing ages of 7, 28 and 90 days was recorded. Different tests of durability were applied on samples like ultrasonic pulse wave test, absorption and sorptivity. For further investigation all the results were compared and noticed that WMP has shown good results and enhancing mechanical properties of concrete mix on partially replacing with sand and cement in set proportions. Moreover, it will solve the problem of environmental health hazard.
Harlokesh Narayan Yadav,Uma Shankar Sharma,Surender Singh,Yogendra Kumar Gupta 경희대학교 융합한의과학연구소 2019 Oriental Pharmacy and Experimental Medicine Vol.19 No.4
Mercury generates free radicals and oxidative stress which are associated with renal injury. Tribulus terrestris (TT), Boerhavia difusa (BD), and Terminalia chebula (TC) have anti-infammatory and antioxidant properties. Hydroalcoholic extract of combination of TT, BD and TC were evaluated against mercuric chloride induced nephrotoxicity. Rats (n=6) were treated with combination of TT, BD and TC in three diferent doses (198, 300 and 600 mg/kg) of equal ratio of each drug and Combination per se. Drugs were administered orally for period of 7 days. Nephrotoxicity was induced by single dose of mercuric chloride (5 mg/kg, i.p.) on ffth day. Combination of above drugs at all three doses signifcantly (p<0.05) decrease blood urea nitrogen, serum creatinine, malondialdehyde and increase glutathione, superoxide dismutase and glutathione peroxidase. While treatment of 300 and 600 mg/kg signifcantly decreases the level of liver fatty acid binding protein (L-FABP) and kidney injury molecule-1 (Kim-1) and administration of combination of 300 mg/kg signifcantly decreases mercury accumulation in kidney tissues as compared to mercuric chloride control group. Our results indicate that treatment of combination of TT, BD and TC exerted signifcant protection against renal damage induced by mercuric chloride possibly due to decrease the renal accumulation of mercury and antioxidant activity.