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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

Small caliber overtube-assisted colonoscopy

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World Journal of Gastroenterology 2007年第44期13卷 5933-5937页

作者： Shai Friedland roy M Soetikno Stanford University School of Medicine and VA Palo Alto Health Care System United States

AIM: To combine the benefits of a new thin flexible scope with elimination of excessive looping through the use of an overtube. METHODS: Three separate retrospective series. Series 1: 25 consecutive male patients undergoing unsedated colonoscopy using the new device at a Veteran's hospital in the United States. Series 2: 75 male patients undergoing routine colonoscopy using an adult colonoscope, pediatric colonoscope, or the new device. Series 3: 35 patients who had incomplete colonoscopies using standard instruments. RESULTS: Complete colonoscopy was achieved in all 25 patients in the unsedated series with a median cecal intubation time of 6 min and a median maximal pain score of 3 on a 0-10 scale. In the 75 routine cases, there was significantly less pain with the thin scope compared to standard adult and pediatric colonoscopes. Of the 35 patients in the previously incomplete colonoscopy series, 33 were completed with the new system. CONCLUSION: Small caliber overtube-assisted colonoscopy is less painful than colonoscopy with standard adult and pediatric colonoscopes. Male patients could undergo unsedated colonoscopy with the new system with relatively little pain. The new device is also useful for most patients in whom colonoscopy cannot be completed with standard instruments.

关键词： Colonoscopy Endoscopy Colon Cancer Colon cancer screening

A Counterbalanced Approach to Content-based Language Teaching

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外语与外语教学 2013年第5期 5-9,17页

作者： roy LYSTER Department of Integrated Studies in Education of McGill University Montr6al Canada H3A1Y2

Content-based language teaching(CBLT)has come to be known as an effective and motivating way to develop higher levels of communicative ability than more traditional grammar-based *** traditional methods isolate the target language from any substantive content except for the mechanical workings of the language itself,CBLT enriches classroom discourse in a way that provides both a cognitive basis for language learning and a motivational basis for purposeful ***,how ever,does not preclude language instruction but instead promotes its integration through a counterbalanced approach that entails a dynamic interplay betw een language and *** on classroom-based research,this paper illustrates the feasibility and effectiveness of a counterbalanced approach to CBLT whose flexibility has the potential to accommodate a range of instructional settings.

关键词： counterbalanced approach content-based language teaching(CBLT) feasibility and effectiveness

Effects on prey-predator with different functional responses

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International Journal of Biomathematics 2017年第8期10卷 141-162页

作者： Banani roy Sankar Kumar roy M. H. A. Biswas Department of Applied Mathematicswith Oceanology and Computer Programming Vidyasagar University Midnapore 721102 West Bengal India Mathematics Discipline Science Engineering and Technology SchoolKhulna University Khulna 9208 Bangladesh

In this paper, we investigate the effects on prey of two predators which are also related in terms of prey-predator relationship. Different types of functional responses are con- sidered to formulate the mathematical model for predator and generalist predator of our proposed model. Harvesting effort for the generalist predator is considered and the density-dependent mortality rate for predator and generalist predator is incorporated in our proposed model. Local stability as well as global stability for the system is dis- cussed. We analyze the different bifurcation parameters to evaluate Hopf bifurcation in the neighborhood of interior equilibrium point. Finally, some numerical simulations and graphical figures are provided to verify our analytical results with the help of different sets of parameters.

关键词： Prey-predator model local and global stabilities Hopf bifurcation.

Bi-level Programming for Stackelberg Game with Intuitionistic Fuzzy Number: a Ranking Approach

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Journal of the Operations Research Society of China 2021年第1期9卷 131-149页

作者： Sumit Kumar Maiti Sankar Kumar roy School of Applied Sciences and Humanities Haldia Institute of TechnologyPurba MidnaporeWB 721657India Department of Applied Mathematics with Oceanology and Computer ProgrammingVidyasagar UniversityMidnaporeWB 721102India

This paper introduces a ranking function procedure on a bi-level programming for Stackelberg game involving intuitionistic fuzzy *** fuzzy num-ber is considered in many real-life situations,so it makes perfect sense to address decision-making problem by using some specified intuitionistic fuzzy *** this paper,intuitionistic fuzziness is characterized by a normal generalized triangular intuitionistic fuzzy number.A defuzzification method is introduced based on the pro-portional probability density function associated with the corresponding membership function,as well as the complement of non-membership *** the proposed ranking technique,a methodology is presented for solving bi-level programming for Stackelberg *** application example is provided to demonstrate the applica-bility of the proposed methodology,and the achieved results are compared with the existing methods.

关键词： Bi-levelprogramming Triangular intuitionistic fuzz ynumber Ranking function Nonlinear programming Optimal solution

Remediation of Fly Ash Dumpsites Through Bioenergy Crop Plantation and Generation: A Review

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Pedosphere 2018年第4期28卷 561-580页

作者： Madhumita roy Roopali royCHOWDHURY Pritam MUKHERJEE Department of Biotechnology Techno India University

Utilization of fly ash, a byproduct of coal combustion in thermal power plants, is a sustainable use of waste for power *** fly ash as waste in landfills/ash ponds may not only be regarded as a loss of valuable land and essential nutrients, but also pose a significant health hazard due to fine air-borne particles and leaching of heavy metals. The presence of essential macro-and micronutrients and its porosity make fly ash an excellent soil amendment for plant growth as an organic nitrogen(N) and carbon(C)supplementation. As harmful heavy metals make fly ash unsafe for agronomy, bioenergy crop plantation and energy generation from different thermochemical conversions of the biomass would be an ideal method for coal fly ash utilization through which carbon-neutral fuel can be generated from fossil fuel, thus reducing climate change impact. This review summarizes the development of bioenergy plantation and silviculture at fly ash dumpsites with an integrated phyto-bio-rhizo-mycoremediation approach and assesses utilization of the valuable biomass for thermal energy, electricity, and biofuel generation with inclusion of a SWOT analysis(a strategic technique typically used to help identify the strength, weakness, opportunities, and threat). Bioenergy crop production through integrated phytomanagement can generate billions of dollars of wealth from waste and provides a sustainable solution for fly ash management,with environmental, economic, and social benefits.

关键词： biofuel production biomass-generating crops carbon-neutral fuel health risk heavy metal land use phytoremediation soil amendment

Phase-controlled propagation of surface plasmons

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Light(Science & Applications) 2017年第1期6卷 466-474页

作者： Basudeb Sain roy Kaner Yehiam Prior Department of Chemical Physics Weizmann Institute of ScienceRehovot 76100Israel

Directional emission of electromagnetic radiation can be achieved using a properly shaped single antenna or a phased array of individual *** of the individual phases within an array enables scanning or other manipulations of the emission,and it is this property of phased arrays that makes them attractive in modern ***,the propagation of surface plasmons at the interface between metal films and dielectric materials can be determined by shaping the individual surface nanostructures or via the phase control of individual elements in an array of such ***,we demonstrate control of the propagation of surface plasmons within a linear array of *** generic situation of plasmonic surface propagation that is different on both sides of a metal film provides a unique opportunity for such control:plasmons propagating on the slower side feed into the side with the faster propagation,creating a phased array of interfering antennas and thus controlling the directionality of the wake *** further show that by shaping the individual nanoantennas,we can generate an asymmetric propagation geometry.

关键词： FDTD NSOM phased array plasmonic wakes surface plasmons

Parentage analysis in Gabonese colonies of soil-feeding termites belonging to the Cubitermes sp. affinis subarquatus complex of species （Termitidae＂ Termitinae）

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Insect Science 2010年第2期17卷 84-90页

作者： Virginie roy Lise Dupont Myriam Harry Unite Mixte de Recherche 7618 Bioemco Universite Paris 12-Val de Mame 61 avenue du Gen6ral de Gaulle 94010 Creteil cedex Laboratoire Evolution Genomes et Speciation UPRg034 Centre National de la Recherche Scientifique 91198 Gif sur YvetteFrance

Cubitermes spp. are widely distributed soil-feeding termite species in sub- Saharan Africa which play a fundamental role in soil structure and fertility. A complex of at least four cryptic species （i.e., Cubitermes sp. affunis subarquatus complex of species） has been recently described using molecular markers. In order to investigate the breeding system of these species, five microsatellite markers were used to carry out parentage and re- latedness analyses in 15 Gabonese colonies. Monogamy was confirmed as the predominant reproductive organization in Cubitermes spp. （76% of the colonies）. Within 30% of these monogamous colonies, a high relatedness between reproductives was shown, suggesting that mating between related individuals occurs. However, Cubitermes colonies can deviate from monogamy. Indeed, parental contributions by at least two related reproductives of the same sex were revealed in four colonies and polyandry was demonstrated in two of them. Infiltration of reproductives in the colony is the most plausible explanation for such cases of polygamy in Cubitermes spp.

关键词： breeding system Cubitermes spp. microsatellite markers monogamy soil- feeding termites

Search for H I emission from superdisk candidates associated with radio galaxies

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Research in Astronomy and Astrophysics 2019年第6期19卷 71-78页

作者： Abhijeet Anand Nirupam roy Gopal-Krishna Max-Planck-Institut fur Astrophysik Karl-Schwarzschild-Str. 1 D-85741 Garching Germany Department of Physics Indian Institute of Science Bangalore - 560012 India Aryabhatta Research Institute of Observational Sciences (ARIES) Manora Peak Nainital - 263129 India Max-Planck-Institut fur Radioastronomie Auf dem Hugel 69 53121 Bonn Germany

Giant gaseous layers(termed “superdisks”) have been hypothesized in the past to account for the strip-like radio emission gap(or straight-edged central brightness depression) observed between twin radio lobes, in over a dozen relatively nearby powerful Fanaroff-Riley Class II radio galaxies. They could also provide a plausible alternative explanation for a range of observations. Although a number of explanations have been proposed for the origin of the superdisks, little is known about their material content. Some X-ray observations of superdisk candidates indicate the presence of hot gas, but a cool dusty medium also seems to be common. If they are entirely or partly composed of neutral gas, then it may be directly detectable and we report here a first attempt to detect/image any neutral hydrogen gas present in the superdisks that are inferred to be present in four nearby radio galaxies. We have not found a positive H I signal in any of the four sources, resulting in tight upper limits on the H I number density in the postulated superdisks,estimated directly from the central rms noise values of the final radio continuum subtracted image. The estimated ranges of the upper limit on neutral hydrogen number density and column density are 10^-4-10^-3 atoms per cm3 and 10^19-10^20 atoms per cm^2, respectively. No positive H I signal is detected even after combining all the four available H I images(with inverse variance weighting). This clearly rules out an H I dominated superdisk as a viable model to explain these structures, however, the possibility of a superdisk being composed of warm/hot gas still remains open.

关键词： galaxies:active galaxies:general galaxies:structure radio lines:galaxies