检索结果-南通市图书馆

Effect of process parameter on the flowability of nanocrystalline CoNiCrAlY powder synthesized by mechanical milling

引用

Particuology 2024年第9期92卷 210-223页

作者： Annadaa Shankara Dash Indranil Manna Deepa Devapal Sharad Chandra Sharma jyotsna dutta majumdar School of Nanoscience and Technology IIT KharagpurWest BengalIndia BIT Mesra RanchiJharkhandIndia Department of Metallurgical and Materials Engineering IIT KharagpurWest BengalIndia Vikram Sarabhai Space Centre ThiruvanthapuramKeralaIndia

The present study concerns understanding the effect of process parameters on the characteristics and flowability of nanocrystalline CoNiCrAlY powder synthesized by mechanical *** milling has been conducted in a planetary ball mill with tungsten carbide(WC)ball,with ball to powder ratio of 10:1 at 300 rpm speed,using 1%stearic acid and toluene as process control agent(PCA)with time varying from 10 h to 36 *** synthesized nanocrystalline powder were characterized by Scanning Electron Microscopy,X-ray Diffraction technique,X-ray Photoelectron Spectroscopy,and Differential Scanning ***,flowability in terms of Hausner ratio was assessed by Tap Density *** particle size of the powder was found to decrease from 33μm to 22μm after 10 h of milling and further increases to 43μm and 38μm after 25 and 36 h of milling,respectively,in stearic acid ***,in toluene medium particle size continuously decreases from 33μm to 9.7μm with increasing milling *** particle morphology changes from spherical to platelet shape at low milling hours in both of the *** 25 h of milling,the shape of the particles is nearly spherical for stearic acid and irregular for toluene used as a *** size was found to decrease with increasing milling time from 147 nm to 7.7 nm and to 6.4 nm in stearic acid and toluene media,*** was presence ofγ,γʹ,β,hcp-Co,Al_(2)O_(3)and AlOOH phases on the powder particles milled in both the *** measured Hausner ratio of the powders was found to vary from 1.18 to 1.32 in stearic acid medium,and was found to increase with increasing milling *** the other hand,in toluene media flowability decreases(Hausner ratio increases from 1.33 to 1.44)with increasing milling time.

关键词： Mechanical milling Microstructure Process control agent(PCA) CoNiCrAlY Toluene Stearic acid Flowability

来源：

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

Elemental micro-segregation characteristic of fiber laser welded Hastelloy C-276 sheet

引用

Transactions of Nonferrous Metals Society of China 2018年第11期28卷 2237-2248页

作者： Kalinga Simant BAL jyotsna dutta majumdar Asimava ROY CHOUDHURY Department of Mechanical Engineering Indian Institute of TechnologyKharagpurWest Bengal 721302India Department of Metallurgical ＆ Materials Engineering Indian Institute of TechnologyKharagpurWest Bengal 721302India

The elemental micro-segregation characteristic within the weld zone for ytterbium fiber laser welded Hastelloy C-276sheet was investigated. The analysis of segregation ratio and equilibrium distribution coefficient of elements, determined throughEDS data, indicate the reduction in micro-segregation of elements compared with the previous reported literatures for laser weldedHastelloy C-276. High melting efficiency of ytterbium fiber laser, reduction in the amount of linear heat input, and high cooling rateof the mushy zone lead to the reduction in micro-segregation. The melting efficiency of ytterbium fiber laser for welding of HastelloyC-276 of 64% is higher than that （48%） of conventional welding methods. High melting efficiency leads to the reduction in the linearheat input required for welding. Hence, in the present investigation, the same was found to substantially reduce as compared to theprevious reported literature. The cooling rate from liquidus temperature to solidus temperature at the weld centerline was found to bein the order of 10^3℃/s. Cellular dendritic substructure that constituted for lower micro-segregation was formed at the weldcenterline.

关键词： Hastelloy C-276 alloy laser welding fiber laser micro-segregation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modelling and Simulation of Hydro-gel Growth Mechanism by Analysis of Experimental Data

引用

Chinese Journal of Polymer Science 2014年第3期32卷 350-361页

作者： Priyadarshi majumdar Jyotinagar Bidyasree Niketan H.S.School GET IIT-JEE BE 89SEC:ISalt Lake CityKolkata 700064India

We have experimentally studied the growth process of a water-absorbing polymer commonly known as hydro-gel. We took a number of spherical beads, immersed them in pure water, measured their diameters at regular intervals of time and plotted graphs showing the change in volume with the time of immersion, to analyze their swelling properties. We have formulated a dynamical model on the basis of curve-fitting to our experimental data. Our mathematical modelling is devoted solely towards the explanation of the swelling of spherical hydro-gels and we have interpreted our observations on these basis. And finally evaluating the constants of the process, we have shown that the results obtained from our modelling and numerical simulation exactly match the experimental data. The justification of this new approach lies in its successful application for the complete explanation of our observations through numerical and analytical ways.

关键词： Hydro-gel Experimental growth study Mathematical modelling Numerical analysis.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of patch size, disturbances on diversity and structural traits of tropical semi-evergreen forest in the lowland Indo Burma hotspot: implication on conservation of the threatened tree species

引用

Journal of Mountain Science 2016年第8期13卷 1397-1410页

作者： Koushik majumdar Badal Kumar DATTA Plant Taxonomy and Biodiversity Laboratory Department of Botany Tripura University

Information on geographic distribution, population and threat status of most globally red listed species in the Indo Burma zone are inadequate. Given the increase in the prevalence of isolated forest patches in the part of this hotspot, evaluation is necessary on how size of the remnant forest patches and on-going disturbances affects structure and diversity of remaining habitats including the population of some globally threatened tree species. Quantitative vegetation inventory by 500 m long and lO m wide （0.5 ha） line transects were randomly set in nine fragmented tropical semi-evergreen forest patches in Tripura, Northeast India. The studied forests patches grouped into small, medium and large based on their respected sizes. Spatial variability was analysed in woody species diversity and structure along the patch size gradients and their response to both patch size and anthropogenic disturbances. Out of 167 species, 13 identified as red-listed species by IUCN under the present inventory. Most of the diversity and structural parameters showed statistically significant positive response with the forest patch size, except for stand dominance, disturbance, sapling density and number of aggregated distribution pattern decreased when patch size increased. In addition, most of the diversity and structural attributes showed negative response with disturbances. Present baseline data would serve as an effective tool for management and protection of this important forest type. Future habitat restoration programme and strategies for relocation of additional population and re-introduction of those globally threatened trees are recommended.

关键词： Forest diversity Semi-evergreen forest Threatened species Population composition IndoBurma zone

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Observation of~100%valley-coherent excitons in monolayer MoS_(2) through giant enhancement of valley coherence time

引用

Light(Science & Applications) 2023年第8期12卷 1644-1650页

作者： Garima Gupta Kenji Watanabe Takashi Taniguchi Kausik majumdar Department of Electrical Communication Engineering Indian Institute of ScienceBangaloreIndia Research Center for Functional Materials National Institute for Materials ScienceTsukubaJapan international Center for Materials Nanoarchitectonics National Institute for Materials ScienceTsukubaJapan

In monolayer transition metal dichalcogenide semiconductors,valley coherence degrades rapidly due to a combination of fast scattering and inter-valley exchange *** leads to a sub-picosecond valley coherence time,making coherent manipulation of exciton a highly challenging task Using monolayer MoS_(2) sandwiched between top and bottom graphene,here we demonstrate fully valley-coherent excitons by observing~100%degree of linear polarization in steady state *** is achieved in this unique design through a combined effect of(a)suppression in exchange interaction due to enhanced dielectric screening,(b)reduction in exciton lifetime due to a fast inter-layer transfer to graphene,and(c)operating in the motional narrowing *** disentangle the role of the key parameters affecting valley coherence by using a combination of calculation(solutions of Bethe-Salpeter and Maiallle-Silva-Sham equations)and a careful choice of design of experiments using four different stacks with systematic variation of screening and exciton *** the best of our knowledge,this is the first report in which the excitons are found to be valley coherent in the entire lifetime in monolayer semiconductors,allowing optical readout of valley coherence possible.

关键词： coherent monolayer lifetime

来源：

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

Comparative Assessment of the Relationship of Satellite Data with the Above Ground Biomass of Sal Trees(Shorea robusta) Determined from Phenologically Different Time Periods

引用

Geo-Spatial Information Science 2011年第3期14卷 177-183页

作者： Nilanchal Patel Arnab majumdar Department of Remote Sensing Birla Institute of Technology Mesra

The Above Ground Biomass(AGB) estimates of vegetation comprise both the bole biomass determined through a volumetric equation and litter biomass collected from the *** mature trees,the AGB estimated in phenologically different time periods is directly affected by the litter biomass since the Diameter at Breast Height(DBH) and height(H) of such trees that are used in the estimation of bole biomass would remain unchanged over a reasonable time *** the present study,we have determined the AGB of Sal trees(Shorea robusta) in two contrasting seasons:the peak green period in October being devoid of lit-ter on the ground and the leaf shedding period in February with abundant amount of litter present on the *** of AGB for the month of February included the litter *** contrast,the AGB for October represented only the bole *** was estimated for ten different plots selected in the study *** AGB estimated from ten sampling plots for each time period was re-gressed with the individual tree parameters such as the average DBH and height of trees measured from the corresponding *** regression analysis exhibited a significantly stronger relationship between the AGB and DBH for the month of October as compared to ***,the correlation between the remotely sensed derived data and AGB was also found to be significantly higher for the month of October than *** observation indicates that inclusion of the litter biomass in AGB will tend to decrease the re-gression relationship between AGB and DBH and also between the remotely sensed data and ***,these conclusions invite careful consideration while estimating AGB from satellite data in phenologically different time periods.

关键词： above ground biomass bole biomass diameter at breast height litter biomass remotely sensed data

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Polarization-controlled optical holography using flat optics

引用

Light(Science & Applications) 2020年第1期9卷 724-725页

作者： Arka majumdar Shane Colburn Electrical and Computer Engineering University of WashingtonSeattleWA 98195USA

Due to the large number of degrees of freedom offered by nanoscale scatterers,a single flat optic can project different images at different distances depending on the polarization of the light,opening up opportunities... 详细信息

关键词： Polarization optics flat

来源：

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

Oilfield geothermal resources of the Upper Assam Petroliferous Basin,NE India

引用

Energy Geoscience 2021年第4期2卷 246-253页

作者： Dilip majumdar Abhilekha Devi Department of Applied Geology Dibrugarh UniversityAssam786004India

Extracting geothermal energy from the oil-producing fields is an experimental venture *** exploitation and utilization of geothermal energy can partly reduce the larger dependence on conventional non-renewable energy sources like oil,gas,coal,and other fossil fuels,and has a bright *** Upper Assam Basin is a mature petroliferous basin of NE India,where there are several hundred low production,high water cut,or abandoned oil and gas wells that can be retrofitted as geothermal wells instead of drilling new *** will help bridge the gap of growing energy demand and limited supply in energy-deficient state like *** away from the active plate boundaries and in lack of active volcanism,the Upper Assam Basin remains a low-to-medium enthalpy geothermal fluid *** deeper reservoir in this regard can,therefore,be the best candidate for the introspection of the potential geothermal energy reservoir *** selection of a deeper horizon considered in the present case has been the stratified reservoirs of the Lakadong-Therria(Lk-Th)Formation,Sylhet Group of the Lower Eocene age occurring at a variable depth of 3400 me 4600 *** Lk-Th Formation possesses a fair-quality reservoir with lateral continuity and favourable petrophysical *** this study,representative gamma-ray(GR)and resistivity(R)logs were examined to work out lithology,and bed boundary demarcation,*** total Formation thickness varies from 97 to 157 m;the individual sand body thickness is up to 6 *** reservoir parameters,e.g.,porosity(φ=8-33%),water saturation(S_(w)=4.57-95.15%),geothermal gradient(2.71℃/100m to 3.92 C/100 m at 4300 m and 3608 m)respectively,and theoretical estimate of high heat flux in the range 70e100 mW/m^(2)/s,are the necessary yard-stick to measure the subsurface geothermal *** energy extraction will have the potential in facilitating energy utilization for industrial purposes,especially in tea processing units pr

关键词： Upper Assam Petroliferous Basin Geothermal energy Water cut Abandoned oil/gas well Geothermal gradient

来源：

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

OCSO-CA:opposition based competitive swarm optimizer in energy efficient IoT clustering

引用

Frontiers of Computer Science 2022年第1期16卷 77-87页

作者： Arpita BISWAS Abhishek majumdar Soumyabrata DAS Krishna Lal BAISHNAB Department of Electronics and Communication Engineering National Institute of Technology SilcharSilchar788010India Department of Computer Science&Engineering Karunya Institute of Technology&SciencesCoimbatore641114India Department of Electrical Engineering National Institute of Technology SilcharSilchar788010India

With the advent of modern technologies,IoT has become an alluring field of *** IoT connects everything to the network and transmits big data frequently,it can face issues regarding a large amount of energy *** this respect,this paper mainly focuses on reducing the energy loss problem and designing an energy-efficient data transfer scenario between IoT devices and ***,a layered architectural framework for IoT-cloud transmission has been proposed that endorses the improvement in energy efficiency,network lifetime and ***,an Opposition based Competitive Swarm Optimizer oriented clustering approach named OCSO-CA has been proposed to get the optimal set of clusters in the IoT device *** proposed strategy will help in managing intra-cluster and inter-cluster data communications in an energy-efficient ***,a comparative analysis of the proposed approach with the state-of-the-art optimization algorithms for clustering has been performed.

关键词： competitive swarm optimization cloud computing clustering IoT

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Soldiers' load carriage performance in high mountains: a physiological study

引用

Military Medical Research 2017年第3期4卷 132-140页

作者： Tirthankar Chatterjee Debojyoti Bhattacharyya Anilendu Pramanik Madhusudan Pal Deepti majumdar Dhurjati majumdar Defence Institute of Physiology and Allied Sciences Defence Research & Development Organisation Ministry of DefenceGovernment of India Retired from-Institute of Nuclear Medicine and Allied Sciences Defence Research and Development Organization Ministry of DefenceGovernment of India

Background: The present study was designed to evaluate load carriage performance at extremely high altitudes with different loads and walking speeds in terms of physiological evaluation. The degree of maximum oxygen consumption changes at high altitudes was also ***: Twelve Indian Army soldiers were acclimatized at altitudes of 3,505 m and 4,300 m. They walked for 10 minutes on a motorized treadmill at 2.5km/h and 3.5km/h speeds during carrying no loads and three magnitudes of load(10.7kg, 21.4kg, 30kg) at both altitudes. Physiological parameters such as oxygen consumption, energy expenditure, heart rate, and ventilation were recorded for each breath using a gas analyzer. The rating of perceived exertion was also noted after each load carriage session. Maximal oxygen consumption(VO2max) was measured at sea level and the two high altitudes, and respective relative workloads(% of VO2max) were calculated from oxygen consumption. Repeated measure ANOVA was applied to reveal the significant effects of the independent ***: The participants had significant reductions in VO2 max with rising altitude. Marked increases in almost all physiological parameters were observed with increasing load, altitude, and speed. The soldiers expressed heavy perceived exertion levels with higher loads at 3.5km/h at the two high ***: Considering the physiological responses, expressions of perceived exertion and changes in relative work load at both of the high altitudes. Indian soldiers are advised to walk slowly with adequate rest in between their schedules and to carry not more than 32% of their body weight.

关键词： Load carriage High altitude Walking speed Physiological responses

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：