检索结果-南通市图书馆

Modeling Spatial–Temporal Dynamics of Urban Residential Fire Risk Using a Markov Chain Technique

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2019年第1期10卷 57-73页

作者： Rifan Ardianto prem Chhetri School of Business IT and Logistics RMIT (Royal Melbourne Institute of Technology) University

This article applies a Markov chain method to compute the probability of residential fire occurrence based on past fire history. Fitted with the fire incidence data gathered over a period of 10 years in Melbourne, Australia,the spatially-integrated fire risk model predicts the likely occurrence of fire incidents using space and time as key model parameters. The mapped probabilities of fire occurrence across Melbourne show a city-centric spatial pattern where inner-city areas are relatively more vulnerable to a fire than outer suburbia. Fire risk reduces in a neighborhood when there is at least one fire in the last1 month. The results show that the time threshold of reduced fire risk after the fire occurrence is about 2 *** risk increases when there is no fire in the last 1 month within the third-order neighborhood(within 5 km). A fire that occurs within this distance range, however, has no significant effect on reducing fire risk level within the neighborhood. The spatial–temporal dependencies of fire risk provide new empirical evidence useful for fire agencies to effectively plan and implement geo-targeted fire risk interventions and education programs to mitigate potential fire risk in areas where and when they are most needed.

关键词： Australia Markov chain Melbourne Residential fire risk Spatial– temporal analysis

Influence of A-site cation disorder on structural and magnetocaloric properties of Nd_(0.7–x)La_xSr_(0.3)MnO_3(x=0.0, 0.1, 0.2 & 0.3)

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2015年第10期33卷 1072-1080页

作者： Sudharshan Vadnala prem Pal Saket Asthana Department of Physics Indian Institute of Technology Hyderabad

In the present research, the influence of A-site ionic size disorder on structural, magnetic and magnetocaloric properties of Ndo.7_xtaxSr0.3MnO3 （for x=0.0, 0.1, 0.2 ＆ 0.3） compounds were investigated. These compounds were synthesized by solid state reaction route and crystallized in orthorhombic structure with Pnma space group. An average ionic radius 〈rA〉 increased with La-substitution which influenced the physical properties such as the magnetic entropy varying from 4.78 J/kg.K （for x-=0.0） to 3.55 J/kg.K （for x=0.3） and the maximum magnetization at 5 K changing from 3.92 μB （for x=0.0） to 3.59 μB （for x=0.3）. The change in maximum magnetic entropy decreased with increase of A-site average ionic radius. The decrease in magnetic entropy indicated the suppression of lattice disorder that influenced the spin-lattice coupling. The ferromagnetic transition temperature shifted toward room temperature with La substitution. As 〈rA〉 increased, the phase transition changed from first order （for x-=0.0） to second order （for x≥ 0.1） and the refrigeration capacity increased to a significant level. The modest change in magnetic entropy over a wide range of transition temperature might be useful for future active magnetic refrigeration technology.

关键词： manganites magnetocaloric effect relative cooling Curie temperature rare earths

EFFECTS OF UNDERSCOUR DEPTH AND HORIZONTAL SPACING BETWEEN TWO BED PROTECTION BLOCKS ON STABILITY OF FRONTAL BLOCK

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第4期24卷 579-588页

作者： SHAH prem TANAKA Norio YAGISAWA Junji Graduate School of Science and Engineering Saitama University Sakura-ku Saitama-shi Saitama Japan

The stability of a river-bed protection block in a flood event is affected by underscouring of the block. The effects of block spacing on block stability were investigated in different underscour conditions. Three blocks were placed at the bottom in a flume, and the underscour depth of the frontal block and distance between the first and second blocks were changed. Drag and lift forces were measured directly in each experimental condition. Particle Image Velocimetry （PIV） was used to visualize the flow and eva- luate the streamline pattern. Pressure measurements around the block to understand the pressure distribution show that the pressure distribution on the rear and bottom surfaces of the block is significantly affected by changes in block spacing and underscour depth. The experimental results show that for the same underscour gap, lift, and drag coefficients decreased with increasing space between the two blocks. In addition, if the underscour gap is increased with the same horizontal spacing, the lift coefficient increases and drag coefficient decreases. These results demonstrate that wider spacing enhance stability of the frontal block in the underscour condition. Moreover, analysis of block stability with changing underscouring and horizontal spacing shows that bed protection blocks seem to have more stability when the gap between two bed protection blocks was equal to height of the blocks.

关键词： bed protection block stability underscouring Particle Image Velocimetry (PIV)

Recent advances in catalytic combustion of AP-based composite solid propellants

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第3期17卷 1013-1031页

作者： Narendra Yadav prem Kumar Srivastava Mohan Varma Department of Space Engineering&Rocketry India Department of Chemistry Birla Institute of TechnologyMesraRanchiIndia

Composite solid propellants(CSPs) have widely been used as main energy source for propelling the rockets in both space and military applications. Internal ballistic parameters of rockets like characteristic exhaust velocity, specific impulse, thrust, burning rate etc., are measured to assess and control the performance of rocket motors. The burn rate of solid propellants has been considered as most vital parameter for design of solid rocket motors to meet specific mission requirements. The burning rate of solid propellants can be tailored by using different constituents, extent of oxidizer loading and its particle size and more commonly by incorporating suitable combustion catalysts. Various metal oxides(MOs),complexes, metal powders and metal alloys have shown positive catalytic behaviour during the combustion of CSPs. These are usually solid-state catalysts that play multiple roles in combustion of CSPs such as reduction in activation energy, enhancement of rate of reaction, modification of sequences in reaction-phase, influence on condensed-phase combustion and participation in combustion process in gas-phase reactions. The application of nanoscale catalysts in CSPs has increased considerably in recent past due to their superior catalytic properties as compared to their bulk-sized counterparts. A large surface-to-volume ratio and quantum size effect of nanocatalysts are considered to be plausible reasons for improving the combustion characteristics of propellants. Several efforts have been made to produce nanoscale combustion catalysts for advanced propellant formulations to improve their energetics. The work done so far is largely scattered. In this review, an effort has been made to introduce various combustion catalysts having at least a metallic entity. Recent developments of nanoscale combustion catalysts with their specific merits are discussed. The combustion chemistry of a typical CSP is briefly discussed for providing a better understanding on role of co

关键词： Composite solid propellants Burn rate modifier Metallic nano-catalysts Catalytic combustion Thermal decomposition

Astible Rivularis: Bioactive Compounds and Pharmacological Functions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2019年第10期25卷 795-799页

作者： Sunita Timalsena prem Prasad Lamichhane Department of Pharmacology Faculty of Medicine Siriraj Hospital Mahidol University Bangkok (10700) Thailand Department of Microbiology Faculty of Medicine Siriraj Hospital Mahidol University Bangkok (10700) Thailand

Astilbe rivularis Buch. Ham., a rhizomatous perennial herb of the Saxifragaceae family, has been listed in rare species. In traditional medicine the plant has been used for the treatment of ulcer, bleeding during child birth, inflammation, body ache, diarrhea, and dysentery. This article reviews and analyses the traditional use, pharmacological activities of the corresponding bioactive compounds, and toxicological data on A. rivularis species. A. rivularis has been used across Indian subcontinent to treat various human ailments. Its extract consists of alkaloids, flavonoids, coumarins and glycosides. These extracts as well as isolated bioactive compounds demonstrated various biological activities including antimicrobial, anti-peptic ulcer, anti-inflammatory, and antioxidant activity. Toxicological studies of the extract on brine shrimp larvae demonstrated mild toxicity;however no acute toxicity in mice. Although the pharmacological effect of A. rivularis has been poorly explored, the available data validated its use in ethnomedicine. To reveal the cryptic therapeutic potential of the species, research should focus on identification and mechanistic studies of the bioactive compounds.

关键词： Astilbe rivularis ethnomedical pharmacological bioactive compounds toxicological

Evolution of a confined gravelly river to a braided-meandering river in the Late Cretaceous Khasi group,southern Shillong plateau,NE India

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2024年第4期13卷 754-774页

作者： Adrita Choudhuri prem Raj Uddandam Debarati Nag Birbal Sahni Institute of Palaeosciences Lucknow226007India Savitribhai Phule Pune University PuneIndi

This paper intends to unravel the depositional condition of the Basal Conglomerate/Jadukata Formation and the Lower Mahadek Formation in southern Shillong Plateau,NE India deposited during the Late Cretaceous *** studied succession is entirely siliciclastics in composition and was built up on the Precambrian basement ***-of-art facies analysis and palaeocurrent evidence helped us to reconstruct the palaeogeography and *** facies tracts reveal that frequent hyperconcentrated mass flow deposits dominated the proximal part of the river ***,the river evolved to a sandy braided and finally mud-dominated,meandering *** river channel changed its pattern through onlapping and progressive elimination of the accommodation space created by the tectonic subsidence/*** shifts in palaeocurrent direction at different stages of the river evolution confirm the role of tectonics on the river channel *** detrital modes of the sandstones reflecting lithic wacke composition and the recycled orogeny corroborate the *** lateral and vertical facies transition suggests a pull-apart type basin due to ongoing *** analyses also show signatures of the overlapping tectonic conditions supporting the pull-apart basin model.

关键词： Tectonics Hyperconcentrated flows Braided-meandering system Pull-apart rift basin Late Cretaceous south Shillong Plateau

Proximate Composition,Mineral Content and Fatty Acids Analyses of Aromatic and Non-Aromatic Indian Rice

在线全文

学校读者我要写书评

暂无评论

Rice science 2017年第1期24卷 21-31页

作者： Deepak Kumar VERMA prem Prakash SRIVASTAV Agricultural and Food Engineering Department Indian Institute of TechnologyKharagpur 721302India

Awareness on nutritive value and health benefits of rice is of vital importance in order to increase the consumption of rice in daily diet of the human beings. In this study, a total of six aromatic and two non-aromatic rice accessions grown in India were analysed for their nutritional quality attributes including proximate composition, mineral contents and fatty acids. Data with three replications were used to measure Pearson＇s simple correlation co-efficient in order to establish the relationship among various nutritional quality attributes. The result on proximate composition showed that Govind Bhog had the highest moisture（13.57%） and fat（0.92%） content, which signifies its tasty attribute. Badshah Bhog exhibited the highest fibre content（0.85%）, carbohydrate content（82.70%） and food energy（365.23 k Cal per 100 g）. Among the minerals, the higher Ca（98.75 mg/kg）, Zn（17.00 mg/kg） and Fe（31.50 mg/kg） were in Gopal Bhog, whereas the highest Na（68.85 mg/kg） was in Badshah Bhog, the highest K（500.00 mg/kg） was in Swetganga, Khushboo and Sarbati. The highest contents of unsaturated fatty acids viz. oleic acid（49.14%）, linoleic acid（46.99%） and linolenic acid（1.27%） were found in Sarbati, whereas the highest content of saturated fatty acids viz. myristic acid（4.60%） and palmitic acid（31.91%） were found in Govind Bhog and stearic acid（6.47%） in Todal. The identified aromatic rice accessions Gopal Bhog, Govind Bhog and Badshah Bhog and non-aromatic rice accession Sarbati were found nutritionally superior among all eight tested accessions. The nutritional quality oriented attributes in this study were competent with recognized prominent aromatic and non-aromatic rice accessions as an index of their nutritional worth and recommend to farmers and consumers which may be graded as export quality rice with good unique nutritional values in international market.

关键词： aromatic unsaturated nutritional proximate accession carbohydrate oleic vital competent attribute

Efficient Single-Stage Bridgeless AC to DC Converter Using Grey Wolf Optimization

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2022年第11期43卷 487-499页

作者： prema Kandasamy K.prem Kumar Department of Electrical and Electronics Engineering Thangavelu Engineering CollegeChennai-600097India Department of Electrical and Electronics Engineering Rajalakshmi Engineering CollegeChennai-602105India

Bridgeless single-stage converters are used for efficient(alternative current)AC-(direct current)DC *** converters control generators,likeelectromagnetic meso-and micro-scale generators with low *** factorcorrection helps increase the factor of the power *** main advantage ofthe power factor is it shapes the input current for increasing the real power of theAC *** this paper,a two-switch bridgeless rectifier topology is designedwith a power factor correction *** the proposed converter topologyto have good power quality parameters,the closed loop scheme,which uses thegrey wolf optimization(GWO)algorithm,is *** successes ofGWO encourage this research to implement GWO in the *** performanceof the proposed topology is analyzed under different load *** is carried out using the MATLAB/Simulink environment,and theresults are compared with those of conventional(proportional integral derivative)PID and(particle swarm optimization)PSO *** validate the simulation results,a 350-W hardware prototype is implemented,and the voltage ripple,efficiency,and power factor under different load conditions are analyzed and *** comparative study clearly indicates that the proposed convertertopology with a closed loop control scheme using the GWO algorithm improves the power factor to 0.9732 and reduces the voltage ripple to 0.12%with a conversion efficiency of 98.25%.

关键词： Bridgeless AC converter DC converter GWO controller power factor

How we look:European wild moufon and feral domestic sheep hybrids

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2024年第3期70卷 298-303页

作者： Nikica Šprem Elena Buzan Toni Safner Faculty of Agriculture Department of FisheriesApicultureWildlife Management and Special ZoologyUniversity of ZagrebSvetošimunska cesta 2510000 ZagrebCroatia Faculty of Mathematics Natural Sciences and Information TechnologiesUniversity of PrimorskaGlagoljaška 86000 KoperSlovenia Faculty of Environmental Protection Trg mladosti 73320 VelenjeSlovenia Faculty of Agriculture Department of Plant BreedingGenetics and BiometricsUniversity of ZagrebSvetošimunska cesta 2510000 ZagrebCroatia Centre of Excellence for Biodiversity and Molecular Plant Breeding(CroP-BioDiv) Svetošimunska cesta 2510000 ZagrebCroatia

Hybridization between wild animals and feral individuals from closely related domestic species can occur when they share the same *** events are generally regarded as a threat to the genetic integrity and survival of established wild *** aim of this study is to confrm a hybridization between European moufon and feral sheep on the Adriatic island Dugi Otok,where a group of individuals phenotypically indicative of a possible introgression was *** an ovine medium-density SNP array genotypes,we provided genetic evidence of recent gene admixture between the two *** ADMIXTURE analysis suggests that two hybrid individuals had 82.2%and 94.1%of their ancestry attributable to feral sheep,respectively,with the rest of the moufon in *** analysis estimated the combined probabilities for the putative hybrid individuals belonging to one of the hybrid classes at 87.0%and 90.1%,*** main phenotypic differences in the hybrids were observed in the shape of the horns,a stronger horn circumference than in the moufon and weaker than for the sheep,pronounced horn rings,a shorter tail,and intermediate *** therefore recommend constant monitoring of the purity of the moufon population to maintain its genetic *** addition,all feral sheep should be removed from the wild,and released sheep raised in semi-wild conditions should be better controlled.

关键词： crossbreeding gene introgression livestock Ovis gmelinimusimon SNPs