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Effect of tool rotational speed on the particle distribution in friction stir welding of AA6092/17.5 siCp-T6 composite plates and its consequences on the mechanical property of the joint

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Defence Technology（防务技术） 2020年第2期16卷 381-391页

作者： Uttam acharya Barnik saha Roy subhash Chandra saha Department of Mechanical Engineering National Institute of Technology AgartalaBarjalaJiraniaWest Tripura799046India

This study investigates the effect of tool rotational speed(TRs)on particle distribution in nugget zone(NZ)through quantitative approach and its consequences on the mechanical property of friction stir welded joints of AA6092/17.5 siCp-T6 composite.6 mm thick plates are welded at a constant tool tilt angle of 2°and tool traverse speed of 1 mm/s by varying the TRs at 1000 rpm,1500 rpm and 2000 rpm with a taper pin profiled *** analysis shows large quantity of uniformly shaped smaller size siC particle with lower average particle area which are homogeneously distributed in the *** fragmentation of bigger size particles has been observed because of abrading action of the hard tool and resulting shearing effect and severe stress generation due to the rotation of *** particles occupy maximum area in the matrix compared to that of the base material(BM)due to the redistribution of broken particles as an effect of *** migration of particles towards the TMAZ-NZ transition zone has been also encountered at higher TRs(2000 rpm).The microhardness analysis depicts variation in average hardness from top to bottom of the NZ,minimum for 1500 rpm and maximum for 2000 *** impact strength at 1000 rpm and 1500 rpm remains close to that of BM(21.6 J)while 2000 rpm shows the accountable *** maximum joint efficiency has been achieved at 1500 rpm(84%)and minimum at 1000 rpm(68%)under tensile *** analysis shows mixed mode of failure for BM,1000 rpm and 1500 rpm,whereas 2000 rpm shows the brittle mode of failure.

关键词： Friction stir welding Aluminium matrix composite Tool rotational speed Particle distribution Mechanical property

Phytopharmacological evaluation and anti-asthmatic activity of Ficus religiosa leaves

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Asian Pacific Journal of Tropical Medicine 2011年第8期4卷 642-644页

作者： Megha kapoor Nidhi Jasani Niyati acharya sanjeev acharya Vimal kumar Department of Phytopharmaceuticals and Natural Products Institute of PharmacyNirma UniversityAhmedabad-382481India

Objective:To discuss phytopharmacological potential and anti-asthmatic activity of Ficus religiosa(***)(L.).Methods:Fresh leaves of *** were obtained from Vastrapur Lake,Ahmedabad,and dried to obtain *** and acetylcholine were used to guinea pigs to establish bronchospasm *** in vivo study,the aqueous extract of *** leaves (AEFR) at doses of 150 and 300 mg/ kg was administrated to guinea pigs,and the broncho-protective activity of AEFR was compared with aminophylline at 25 mg/*** in in vitro study,and 10 g/mL,20 g/mL,30 g/mL of AEFRL was administrated to guinea pigs,respectively, and mast cell stabilizing activity of AEFR was compared with ketotifen at 10 g/***: In the in-vivo model,pre-treatment with aminophylline(25 mg/kg,ip.) could significantly delay the onset of histamine induced pre-convulsive dyspnea,compared with vehicle control. Administration of AEFRL(150 and 300 mg/kg,ip.) also produced significant effect on latency to develop histamine & acetylcholine induced pre-convulsive *** the mast cell stabilizing model,AEFRL at 10,20 and 30μg/mL could significantly increase the number of intact cells. Conclusions:It can be concluded that AEFRL is effective on histamine & acetylcholine induced bronchospasm in guinea *** addition,AEFRL can potentiate the number of intact cells in the mast cell stabilizing model._____________________________________________________

关键词： Ficus religiosa Peepal Anti-asthmatic Bronchodilator Mast cell stabilizing

Morphological and molecular evidence supports the first occurrence of two fishes, siganus sutor(Valenciennes, 1835)and seriolina nigrofasciata(Rüppell, 1829)(Actinopterygii:Perciformes), from marine waters of Odisha coast, Bay of Bengal, India

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Acta Oceanologica sinica 2020年第6期39卷 26-35页

作者： Tapan k.Barik surya N.swain Bijayalaxmi sahu Bibarani Tripathy Usha R.acharya Post Graduate Department of Zoology Berhampur UniversityBerhampur 760007OdishaIndia

Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological *** extent to which the geographic distribution of marine organism has reshaped by human activities remains *** limitations intrinsic to morphology-based identification systems have engendered an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species,particularly those that are prone to overexploitation and/or market *** the present study,however,an attempt has been taken to identify two locally adapted fish species,siganus sutor(Valenciennes,1835)and seriolina nigrofasciata(Rüppell,1829)of order Perciformes,which happens to be the first record in Odisha coast,Bay of *** diagnostic characteristics of siganus sutor are:dorsal fin XIII-10,anal fin VII-9,pectoral fin 15,pelvic fin II-3,while that of seriolina nigrofasciata dorsal fin VI-I-35,anal fin I-17,pectoral fin 16,pelvic fin *** COI barcodes generated in this study were matched with reference sequences of expected species,according to morphological *** and likelihood phylogenetic trees were drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at the species *** phylogeographic studies based on haplotype network and migration rates suggest that both the species were not panmitic and the high-frequency population distribution indicates successful *** result of this study provides an important validation of the use of DNA barcode sequences for monitoring species diversity and changes within a complex marine ecosystem.

关键词： siganus sutor seriolina nigrofasciata morphological characteristics DNA Barcoding

Performance analysis of karanja and kusum oils as alternative bio-diesel fuel in diesel engine

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International Journal of Agricultural and Biological Engineering 2011年第2期4卷 23-28页

作者： saroj kumar acharya A k Mishra M Rath C Nayak Department of Mechanical Engineering S O A UniversityBhubaneswarOrissaIndia 751030

scarcity of conventional petroleum resources has promoted research in alternative fuels for internal combustion *** various possible options,fuels derived from triglycerides(vegetable oils/animal fats)are promising for the substitution of fossil diesel *** oils poses some characteristics like durability,high viscosity and low volatility compared to mineral diesel *** the present work,experiments were designed to study the effect of reducing kusum and karanja oil’s viscosity by preheating the fuel,using a shell and tube heat *** acquired engine data were analyzed for various parameters such as brake thermal efficiency,brake specific energy consumption(BsEC),emission of exhaust gases like CO,CO_(2),HC and NO_(x).In operation,the engine performance with kusum and karanja oil(preheated),was found to be very close to that of *** preheated oil's performances were found to be slightly inferior in efficiency due to low heating *** performance of karanja oil was found better than kusum oil in all respects.

关键词： diesel engine bio-diesel kusum oil karanja oil alternative fuel preheating viscosity heat exchanger

Modeling the transmission dynamics of a time-delayed epidemic model with saturated treatment rate

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International Journal of Biomathematics 2023年第7期16卷 11-45页

作者： Ranjit kumar Upadhyay sattwika acharya Department of Mathematics&Computing Indian Institute of Technology(Indian school of Mines)Dhanbad Jharkhand-826004 India

In this paper,an attempt has been made to explore a new delayed epidemiological model assuming that the disease is transmitted among the susceptible population and possessing nonlinear incidence function along with a saturated treatment *** attention is paid to the positivity and boundedness of the solutions and the bifurcation of the dynamical system as *** reproduction number is being calculated,and considering the latent period as a bifurcation parameter,it has been examined that a Hopf-bifurcation occurs near the endemic equilibrium point while the parameter attains critical *** have also discussed the stability and direction of Hopf-bifurcation near the endemic equilibrium point,the global stability analysis and the optimal control *** conclude that the system reveals chaotic dynamics through a specific time-delay *** simulations are being performed in order to explain the accuracy and effectiveness of the acquired theoretical results.

关键词： Infectious disease treatment rate chaotic dynamics bifurcation theory incidence function transmission dynamics global stability optimal control

secondary hemochromatosis as a result of acute transfusion-induced iron overload in a burn patient

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Burns & Trauma 2016年第2期4卷 160-163页

作者： Michael Amatto Hernish acharya University of Alberta 8440112 StreetEdmontonAB T6G 2B7Canada Glenrose Rehabilitation Hospital #112610230111 AveEdmontonAB T5G 0B7Canada

Background:Red blood cell transfusions are critical in burn *** subsequent iron overload that can occur from this treatment can lead to secondary hemochromatosis with multi-organ *** Presentation:While well recognized in patients receiving chronic transfusions,we present a case outlining the acute development of hemochromatosis secondary to multiple transfusions in a burn ***:simple screening laboratory measures and treatment options exist which may significantly reduce morbidity;thus,we believe awareness of secondary hemochromatosis in those treating burn patients is critical.

关键词： secondary hemochromatosis Transfusion Iron overload Burn patients

Applicability of unique scarf joint configuration in friction stir welding of AA6061-T6:Analysis of torque,force,microstructure and mechanical properties

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Defence Technology（防务技术） 2022年第4期18卷 567-582页

作者： Durjyodhan sethi Uttam acharya shashank shekhar Barnik saha Roy Department of Mechanical Engineering National Institute of Technology AgartalaBarjalaJiraniaWest TripuraPin-799046India Department of Materials science and Engineering Indian Institute of Technology KanpurKanpur208016India

The present research introduces a unique concept of scarf joint technique in friction stir welding(FsW) of aluminum alloy AA 6061-T6 plates and an investigation on weld quality.A new joint configuration with two distinct scarf angles(75°and 60°) was considered in this *** various aspects of welding were compared with contemporary simple square butt(ssB) joint *** was carried out at a constant tool rotation speed(TRs),tool traverse speed(TTs) and tool tilt angle of 1100 rpm,2 mm/s and2°,*** results are analyzed in terms of force and torque distribution,microstructure,macrostructure,and mechanical property perspective for different joint *** study reveals the minimum amount of force and torque at 60°scarf angle joint configuration compared to that of square butt joint *** study shows that all the joints were defect-free,and a prominent onion ring was present in the lower portion of the weld nugget(WN).Fine equiaxed grains with a minimum average grain size diameter of 6.82 μm were obtained in the WN of scarf joint configuration(sJC).The maximum ultimate tensile strength(UTs) and maximum average NZ hardness of 267 MPa and83.82 HV0.1were obtained in sJC3 at a scarf angle of 60°.It has been observed from the investigation that the joint efficiency increases from 72.5%(ssB) to 86%(sJC3) at a 60° scarf *** unique characteristic may lay an impetus on probable joint strength enhancement technique without increasing the production cost.

关键词： Friction stir welding Joint configuration Al alloys Force and torque Microstructure Mechanical property

Effect of Zn Concentration on Microstructural,Optical,and Hyperfine Properties of Nanocrystalline a-Fe_(2)O_(3)

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Acta Metallurgica sinica(English Letters) 2014年第4期27卷 563-568页

作者： N.R.Panda D.sahu B.s.acharya P.Nayak s.P.Pati D.Das school of Basic science Indian Institute of Technology BhubaneswarBhubaneswar 751013OdishaIndia school of Physics Sambalpur UniversitySambalpur 768019OdishaIndia school of Chemistry Sambalpur UniversitySambalpur 768019OdishaIndia C.V.Raman College of Engineering Bhubaneswar 752054OdishaIndia Department of Electronic Engineering Tohoku UniversitySendai 980-8579Japan UGC-DAE CsR Sector IIILB-8Bidhan NagarKolkata 700098India

Efforts have been made to prepare nanocomposites of a-Fe2O3-ZnO by wet chemical route with varying concentrations of the *** microstructural properties of the samples are investigated by powder X-ray diffractometry（PXRD） and Transmission electron *** concentration of Zn ions（up to 20 at%） leads to the formation of nanocomposites of a-Fe2O3 and *** of ZnFe2O4 phase is detected by the substitution of higher concentration of Zn2？（30 at%） in the *** average size of the nanoparticles remains in the range of 22–27 nm as obtained from XRD *** results obtained from electron microscopic studies are also close to these *** measurement shows the excitonic peak of ZnO around 390 nm which gets strengthened with Zn *** spectra show the metal–oxygen band below 700 *** temperature Mssbauer studies of the samples show the transition of iron oxide form antiferromagnetic state to paramagnetic state with increasing concentration of Zn2？.sharp quenching of hyperfine field with Zn concentration is observed as the Hintvalue reduced to zero from 51 T.

关键词： Iron oxide ZnO Electron microscopy Mssbauer study

Bone mineral density and disorders of mineral metabolism in chronic liver disease

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World Journal of Gastroenterology 2009年第28期15卷 3516-3522页

作者： Joe George Hosahithlu k Ganesh shrikrishna acharya Tushar R Bandgar Vyankatesh shivane Anjana karvat shobna J Bhatia samir shah Padmavathy s Menon Nalini shah Department of Endocrinology Seth G.S. Medical College and KEM Hospital Department of Gastroenterology Seth G.S Medical College and KEM Hospital Department of Gastroenterology Jaslok Hospital

AIM： To estimate the prevalence and identify the risk factors for metabolic bone disease in patients with cirrhosis. METHODs： The study was performed on 72 Indian patients with cirrhosis （63 male, 9 female; aged 〈 50 years）. Etiology of cirrhosis was alcoholism （n = 37）, hepatitis B （n = 25） and hepatitis C （n = 10）. Twenty-three patients belonged to Child class A, while 39 were in class B and 10 in class C. secondary causes for metabolic bone disease and osteoporosis were ruled out. sunlight exposure, physical activity and dietary constituents were calculated. Complete metabolic profiles were derived, and bone mineral density （BMD） was measured using dual energy X ray absorptiometry. Low BMD was defined as a Z score below -2. REsULTs： Low BMD was found in 68% of patients. Lumbar spine was the most frequently and severely affected site. Risk factors for low BMD included low physical activity, decreased sunlight exposure, and low lean body mass. Calcium intake was adequate, with unfavorable calcium： protein ratio and calcium： phosphorus ratio. Vitamin D deficiency was highly prevalent （92%）. There was a high incidence of hypogonadism （41%）. serum estradiol level was elevated significantly in patients with normal BMD. Insulin-like growth factor （IGF） 1 and IGF binding protein 3 levels were below the age-related normal range in both groups. IGF-1 was significantly lower in patients with low BMD. serum osteocalcin level was low （68%） and urinary deoxypyridinoline to creatinine ratio was high （79%）, which demonstrated low bone formation with high resorption. CONCLUsION： Patients with cirrhosis have low BMD. Contributory factors are reduced physical activity, low lean body mass, vitamin D deficiency and hypogonadism and low IGF-1 level.

关键词： Bone mineral density Liver disease Chronic disease Cirrhosis Bone mineral metabolism Hepatic osteodystrophy