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Influence of Rotational Speed on Microstructure and Mechanical Properties of Dissimilar Metal AISI 304-AISI 4140 Continuous Drive Friction Welds

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Journal of Iron and Steel Research International 2012年第10期19卷 64-73页

作者： G Subhash Chander G Madhusudhan Reddy A venugopal Rao Swarna Bharathi Institute of Science and Technology Khammam 507002APIndia Defense Metallurgical Research Laboratory Kanchanbagh 500058APIndia

Fundamental investigation of continuous drive friction welding of austenitic stainless steel (AISI 304) and low alloy steel (AISI 4140) is described. The emphasis is made on the influence of rotational speed on the microstructure and mechanical properties such as hardness, tensile strength, notch tensile strength and impact toughness of the dissimilar joints. Hardness profiles across the weld show the interface is harder than the respective parent metals. In general, maximum peak hardness is observed on the stainless steel side, while other peak hardness is on the low alloy steel side. A trough in hardness distribution in between the peaks is located on the low alloy steel side. Peak hardness on the stainless steel and low alloy steel side close to the interface increases with a decrease in rotational speed. All transverse tensile joints fractured on stainless steel side near the interface. Notch tensile strength and impact toughness increase with increase in rotational speed up to 1 500 r/min and decrease thereafter. The mechanism of influence of rotational speed for the observed trends is discussed in the torque, displacement characteristics, heat generation, microstructure, fractography and mechanical properties.

关键词： friction welding dissimilar metal joint austenitic stainless steel low alloy steel microstructure impact toughness tensile strength

BHLM:Bayesian theory-based hybrid learning model for multi-document summarization

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International Journal of Modeling, Simulation, and Scientific Computing 2018年第2期9卷 229-250页

作者： S.Suneetha A.venugopal Reddy Computer Science and Engineering Department Hasvita Institute of Engineering and Technology Hyderabad India Jawaharlal Nehru Technological University Hyderabad India

In order to understand and organize the document in an efficient way,the multidocument summarization becomes the prominent technique in the Internet *** the information available is in a large amount,it is necessary to summarize the document for obtaining the condensed *** perform the multi-document summarization,a new Bayesian theory-based Hybrid Learning Model(BHLM)is proposed in this ***,the input documents are preprocessed,where the stop words are removed from the ***,the feature of the sentence is extracted to determine the sentence score for summarizing the *** extracted feature is then fed into the hybrid learning model for ***,learning feature,training error and correlation coefficient are integrated with the Bayesian model to develop ***,the proposed method is used to assign the class label assisted by the mean,variance and probability ***,based on the class label,the sentences are sorted out to generate the final summary of the *** experimental results are validated in MATLAB,and the performance is analyzed using the metrics,precision,recall,F-measure and *** proposed model attains 99.6%precision and 75%rouge-1 measure,which shows that the model can provide the final summary efficiently.

关键词： Multi-document text feature sentence score hybrid learning model Bayesian theory

Impact of mangrove vegetation on seasonal carbon burial and other sediment characteristics in the Vellar-Coleroon estuary, India

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Journal of Forestry Research 2014年第4期25卷 787-794页

作者： Kandasamy Kathiresan venugopal Gomathi Raj Anburaj Kandasamy Saravanakumar Centre of Advanced Study in Marine Biology Faculty of Marine Sciences Annamalai University Parangipettai 608 502 India

This work quantified the total carbon and 12 other sediment characteristics at 10 soil depths, in planted and or natural mangrove forests in comparison with non-vegetated soil for four seasons of the year 2009-2010 in the Vellar-Coleroon estuarine complex, India. The sedi- ment characteristics varied significantly between mangrove-vegetated and non-vegetated habitats or seasons of analysis, but not between soil depths. The mangrove sediments were rich in total carbon and total or- ganic carbon as compared to non-mangrove sediments （p 〈0.01）. Total carbon was 98.2% higher in mature mangroves and 41.8% in planted mangroves than that in non-mangrove soil. Total organic carbon was as much as 2.5 times greater in mature mangroves and 2 times greater in planted mangroves than that in unvegetated soil. Carbon contents also varied many fold by season. Total carbon content was 8.6 times greater during pre-monsoon, 4.1 times greater during post-monsoon and 2.5 times greater during monsoon than during summer （P〈0.01 in all cases）. Similarly, total organic carbon was 5.9 times greater during pre-monsoon, 3.1 times greater during post-monsoon and 69% greater during monsoon than during summer. In general, higher levels of sediment carbon were recorded during pre and post-monsoon seasons than during other seasons. Total carbon concentration was correlated negatively to temperature, sand and phosphorus （P 〈0.01）; positively correlated with redox potential, silt, clay, C/N ratio, potassium （P 〈0.01） and nitrogen （P〈0.05）; but not correlated with soil depth, pH or salinity. This work revealed that the carbon burial was rapid at the annual rate of 2.8% for total carbon, and 6.7% for total organic carbon in mangrove-planted sediment. Cleating of mangroves can result in significantly and rapidly reduced carbon *** study highlights the importance of natural and plantation mangrove stands for conserving sediment carbon in the tropical coastal domain.

关键词： mangrove sediment carbon burial total carbon total organiccarbon

Non-spherical aluminum nanoparticles fabricated using picosecond laser ablation

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International Journal of Minerals,Metallurgy and Materials 2020年第7期27卷 980-986页

作者： A.Brahma Swamulu S.venugopal Rao G.Krishna Podagatlapalli Department of Physics Rajiv Gandhi University of Knowledge TechnologiesNuzvidAndhra Pradesh 521202India Advanced Centre of Research in High Energy Materials(ACRHEM) University of HyderabadHyderabad 500046TelanganaIndia Department of Electronics&Physics Gandhi Institute of Technology and Management Institute of ScienceGandhi Institute of Technology and Management deemed to be UniversityVisakhapatnam 530045Andhra PradeshIndia

We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid(chloroform,CHCl3)with^2 ps laser pulses at an input energy of^350μ*** synthesized aluminum nanoparticles exhibited a surface plasmon resonance peak at^340 *** electron microscopy images of Al nanoparticles demonstrated the spherical morphology with an average size of(27±3.6)*** formation of smaller spherical Al nanoparticles and the diminished growth could be from the formation of electric double layers on the Al *** addition to spherical aluminum nanoparticles,triangular/pentagonal/hexagonal nanoparticles were also observed in the colloidal *** emission scanning electron microscopy images of ablated Al targets demonstrated laser induced periodic surface structures(LIPSSs),which were the high spatial frequency LIPSSs(HSF-LIPSSs)since their grating period was^280 ***,coarse structures with a period of^700 nm were observed.

关键词： ablation picosecond silver polar periodic surfaces electric double layers

Characteristics of La-modified Ni-Al_2O_3 and Ni-SiO_2 catalysts for CO_x-free hydrogen production by catalytic decomposition of methane

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Journal of Energy Chemistry 2013年第6期22卷 853-860页

作者： Chatla Anjaneyulu Velisoju Vijay Kumar Suresh K.Bhargava Akula venugopal Inorganic & Physical Chemistry Division CSIR-Indian Institute of Chemical Technology College of Science Engineering and Health Advanced Materials & Industrial Chemistry School of Applied Sciences RMIT University

Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 mol 1 Ni. A direct relationship between Ni metal surface area and hydrogen yields was established.

关键词： CH4 decomposition Ni-La-Al hydrotalcite Ni metal surface area COx-free H2

Relationship between age, size, fecundity and climatic factors in Panax wangianus an endangered medicinal plant in the sacred grove forest of North-East India

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Journal of Forestry Research 2011年第3期22卷 427-435页

作者： N. venugopal Preeti Ahuja Plant Anatomy Lab Department of Botany North-Eastern Hill University Shillong-793022 Meghalaya India

Panax wangianus （Syn. Panax pseudoginseng） S. C. Sun （Araliaceae） is a critically endangered, medicinal plant of North-East India. The objective of this study was to determine how plant size affects flowering phenology and to evaluate the effect of climatic factors on flowering, fruiting and seed production. Data on vegetative and repro- ductive characters were monitored from 2016 individuals of Panax wangianus population in Law Lyngdoh, Smit sacred grove in Nongkrem, Shillong, India. Leaflet area was measured by a planimeter. Size variables of both vegetative and reproductive traits in different age classes were measured. Climatic factors were recorded from 2007 to 2009. Age was recorded by counting the number of bud scale scars on the rhizome. Light intensity and relative humidity were measured using a photometer, LiCor Model LI-189 and thermohygrometer respectively. Different climatic variables are correlated with vegetative and reproductive phenological events. Statistical analysis revealed that a strong positive correlation was observed between the age versus vegetative and reproductive characters, except 1%–2% plants showed neoteny. Morphological variations were observed in natural conditions on the basis of the number of prong and carpellate conditions. Phenological status revealed that most of the individuals of the age class 35–50 years and above 50 years contributed the most to flowering, fruiting and seed production. Age class was significant to predict the size of the plant and its reproductive capacity. Climatic factors such as temperature, precipitation and relative humidity show synergistic effect on both the vegetative and reproductive phases in Panax wangianus in the undisturbed Nongkrem sacred grove. The color of flowers of P. wangianus also varied depending upon the sunlight intensity. Therefore, in the view of conservationand management, the age class of 35–50 years and above 50 years is the most important for population sustainability.

关键词： Panax wangianus medicinal plant North-East India Nongkrem sacred grove climatic factors vegetative and reproductive relationship with age

Recent research advances on Chromobacterium violaceum

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Asian Pacific Journal of Tropical Medicine 2017年第8期10卷 810-818页

作者： Vijay Kothari Sakshi Sharma divya Padia Institute of Science Nirma UniversityAhmedabad-382481India

Chromobacterium violaceum is a gram-negative bacterium, which has been used widely in microbiology labs involved in quorum sensing(QS) research. Among the QS-regulated traits of this bacterium, violacein production has received the maximum attention. Violacein production in this organism, however is not under sole control of QS machinery, and other QSregulated traits of this bacterium also need to be investigated in better detail. Though not often involved in human infections, this bacterium is being viewed as an emerging pathogen. This review attempts to highlight the recent research advances on Chromobacterium violaceum, with respect to violacein biosynthesis, development of various applications of this bacterium and its bioactive metabolite violacein, and its pathogenicity.

关键词： Antibiotic resistance Chromobacterium violaceum Violacein Quorum Sensing Emerging pathogen

Constrained controllability of nonlinear neutral fractional integrodifferential systems

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Journal of Control and Decision 2017年第2期4卷 81-99页

作者： S.divya K.Balachandran Department of Mathematics Bharathiar UniversityCoimbatoreIndia

In this paper,we study the complete controllability for a class of nonlinear neutral fractional integro-differential systems in a finite interval of time by means of controls whose initial and final values can be assigned in *** result is achieved using the Banach fixedpoint theorem and Schauder’s fixed-point *** numerical examples are provided to demonstrate the effectiveness of the main result.

关键词： Constrained controllability neutral fractional integrodifferential equations fixed point theorem

Central nervous system activity of Illicium verum fruit extracts

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Asian Pacific Journal of Tropical Medicine 2013年第11期6卷 869-875页

作者： divya Chouksey Neeraj Upmanyu RS Pawar Phytochemistry and Pharmacognosy Division VNS Institute of PharmacyNeelbudBHOPALM.P.India R.K.D.F.College of Pharmacy Hoshangabad RoadBhopalM.P.-462047.India

Objective:To research the acute toxicity of Illicium verum(***)fruit extracts and its action on central nervous ***:The TLC and HPTLC techniques were used as fingerprints to determine the chemical components present in *** albino rats and mice were utilized for *** powdered material was successively extracted with n-hexane,ethyl acetate and methanol using a Soxhlet *** toxicity studies were performed as per OECD *** CNS activity was evaluated on parameters of general behavior,sleeping pattern,locomotor activity,anxicty and myocoordination *** animals were trained for seven days prior to experiments and the divided into five groups with six animals in *** drug was administered by intraperitoneal route according to body *** dosing was done as prescribed in each ***:Toxicity studies reported 2 000 mg/kg as toxicological dose and 1/10 of the same dose was taken as therapeutic dose Intraperitoneal injection of all extracts at dose of 200 mg prolonged phenobarbitone induced sleeping time,produced alteration in general behavior pattern,reduced locomotor activity and produced anxiolytic effects but the extracts do not significantly alter muscles coordination *** three extracts of *** at the dose of 200 mg,methanol extract was found to produce more prominent effects,then hexane and ethylacetate ***:The observation suggested that the extracts of I. verum possess potent CNS depressant action and anxiolytic effect without interfering with motor coordination.

关键词： Illicium verum TLC HPTLC Anxiolytic CNS depressant