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Oxygen Barrier of Multiwalled Carbon Nanotube/Polymethyl Methacrylate Nanocomposites Prepared by in situ Method

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Journal of Materials Science & Technology 2012年第5期28卷 391-395页

作者： Ajaya k. Pradhan Sarat k. Swain Department of Chemistry North Orissa University Takatpur Baripada 757003 India Department of Chemistry Veer Surendra Sai University of Technology Burla Sambalpur 768018 India

Multiwalled carbon nanotubes （MWCNTs）/poly（methyl methacrylate）（PMMA） nanocomposites were prepared by ultrasonic assisted emulsifier free emulsion polymerization technique with variable concentration of functionalized carbon nanotubes. MWCNTs were functionalized with H 2 SO 4 and HNO 3 with continuing sonication and polished by H 2 O 2 . The appearance of Fourier transform infrared absorption bands in the PMMA/MWCNT nanocomposites showed that the functionalized MWCNT interacted chemically with PMMA macromolecules. The surface morphology of functionalized MWCNT and PMMA/MWCNT nanocomposites were studied by scanning electron microscopy. The dispersion of MWCNT in PMMA matrix was evidenced by high resolution transmission electron microscopy. The oxygen permeability of PMMA/MWCNT nanocomposites gradually decreased with increasing MWCNT concentrations.

关键词： Nanocomposites Morphology Permeability Dispersion

FINITE ELEMENT ANALYSIS OF A VERTICAL RECTANGULAR PLATE COUPLED WITH AN UNBOUNDED FLUID DOMAIN ON ONE SIDE USING A TRUNCATED FAR BOUNDARY

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Journal of Hydrodynamics 2009年第2期21卷 190-200页

作者： PANI P. k. BHATTACHARYYA S. k. Civil Engineering Department IGIT Sarang Orissa 759146 India Civil Engineering Department IIT Kharagpur 721302 India

The dynamic pressure distribution on a rectangular plate attached to a rigid wall and supporting an infinitely large extent of fluid subjected to a harmonic ground excitation is evaluated in the time domain. Governing equations for the fluid domain are set considering the compressibility of the fluid with negligibly small change in density and a linearized free surface. A far boundary condition for the three-dimensional fluid domain is developed so that the far boundary is truncated at a closer proximity to the structure. The coupled problem is solved independently for the structure and the fluid domain by transferring the acceleration of the plate to the fluid and pressure of the fluid to the plate in sequence. Helmholtz equation for the three-dimensional fluid domain and Mindlin＇s theory for the two-dimensional plate are used for the solution of the interacting domains. Finite element technique is adopted for the solution of this problem with pressure as nodal variable for the fluid domain and displacement for the plate. The time dependent equations are solved in each of the interacting domain using Newmark.fl method. The effectiveness of the technique is demonstrated and the influences of surface wave, exciting frequency and flexibility of the plate on dynamic pressure are investigated.

关键词： fluid-structure interaction compressible fluid linear surface wave truncation boundary dynamic pressure

Performance behaviour of elliptical-bore journal bearings lubricated with solid granular particulates

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Particuology 2016年第4期14卷 51-60页

作者： Faisal Rahmani Jayanta k. Dutt Raj k. Pandey Department of Mechanical Engineering Indian Institute of Technology Delhi New Delhi 110016 India

Journal bearings operating in hot environments and at high temperatures experience accelerated degra- dation of lubricating oils. In such situations, dry granular particulates have emerged as potential media for providing lubrication in journal bearings in place of lubricating oils. Granular particulates do not degrade thermally, even at considerably high temperatures. This work.explores the static and dynamic perfor- mance characteristics of elliptical-bore journal bearings lubricated with granular particulates. It is found that a bearing lubricated with a larger size （2 μm） particles offers better performance compared with that using smaller size （1μm） particles. Bore ellipticity reduces the load-carrying capacity and increases side leak.ge and the coefficient of friction; however, rotor stability is marginally improved at low eccentricity ratios （〈0.6）, followed by significant improvement at high eccentricity ratios （〉0.6）.

关键词： Particulate Journal bearing Grain size Rigid rotor stability Hydrodynamic lubrication

Direct joining of oxygen-free copper and carbon-fiber-reinforced plastic by friction lap joining

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Journal of Materials Science & Technology 2018年第1期34卷 192-197页

作者： L.H. Wu k. Nagatsuk. k. Nak.ta Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki Osaka 567-0047 Japan

Oxygen-flee copper （Cu） was successfully joined to carbon-fiber-reinforced thermoplastic （CFRTP, polyamide 6 with 20wt% carbon fiber addition） by friction lap joining （FLJ） at joining speeds of 200-1600 mm/min with a constant rotation rate of 1500 rpm and a nominal plunge depth of 0.9 ram. It is the first time to report the joining of CFRTP to Cu by FLJ. As the joining speed increased, the tensile shear force （TSF） of joints increased first, and decreased thereafter. The maximum TSF could reach 2.3 k. （ 15 mm in width）. Hydrogen bonding formed between the amide group of CFRTP and the thin Cu20 layer on the Cu surface, which mainly contributed to the joint bonding. The influence factors of the TSF of the joints at different joining speeds were discussed. The TSF was mainly affected by the joining area, the degradation of the plastic matrix and the number and the size of bubbles. As the joining speed increased, the influence factors varied as follows： the joining area increased first and then decreased; the degra- dation of the plastic matrix and the number and the size of bubbles decreased. The maximum TSF was the comprehensive result of the relatively large joining area, small degradation of the plastic matrix and small number and sizes of bubbles.

关键词： Friction lap joining Metal Plastic Carbon-fiber reinforced thermoplastic Dissimilar materials joining

Thermal and Oxygen Barrier Properties of Chitosan Bionanocomposites by Reinforcement of Calcium Carbonate Nanopowder

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Journal of Materials Science & Technology 2014年第8期30卷 791-795页

作者： Sarat k. Swain Satyabrata Dash Sudhir k. k.sk. Rajesh k. Singh Department of Chemistry Veer Surendra Sai University of TechnologyBurlaSambalpur 768018India Department of Chemistry North Orissa UniversityTakatpurBaripada 757003India

Chitosan and calcium carbonate nanopowder（chitosan/CaCO3） bionanocomposites were prepared by solution *** between chitosan and CaCO3 was studied by Fourier transform infrared spectroscopy（FTIR）.Structure and surface morphology of chitosan/CaCO3 bionanocomposites were investigated by X-ray diffraction（XRD） and field emission scanning electron microscopy（FESEM）,*** energy dispersive X-ray spectroscopy（EDS） of chitosan/CaCO3 bionanocomposites was studied in order to establish the elements of *** stability of prepared bionanocomposites was studied by thermogravimetric analysis（TGA） and a substantial increase of thermal stability of virgin chitosan was noticed due to incorporation of CaCO3 *** oxygen permeability was reduced by three times as compared to the raw chitosan due to the dispersion of nano CaCO3 *** and resistance towards dilute acid and alk.li of the prepared bionanocomposite were *** bionanocomposite having gas barrier and thermal stable property may be suitable for pack.ging and biomedical applications.

关键词： Chitosan Nanocomposites Thermal properties Oxygen permeability

Melamine-Formaldehyde Acrylamide and Gum Polymer Impregnated Wood Polymer Nanocomposite

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Journal of Bionic Engineering 2015年第2期12卷 304-315页

作者： Ank.ta Hazarik. Biplab k. Dek. Tarun k. Maji Department of Chemical Sciences Tezpur University Assam-784 028 India

Melamine-formaldehyde acrylamide （MFA） copolymer was prepared and vacuum impregnated into wood in presence of 1,3-dimethylol 4,5-dihydroxyethylene urea （DMDHEU） as crosslink.r, vinyltrichlorosilane （VTCS） modified montmorillonite （MMT） and Gum Polymer （GP） derived from Moringa oleifera as a flame retarding agent under catalyst heat treatment. The formation of MFA and DMDHEU was confirmed by Nuclear Magnetic Resonance （NMR） and Fourier Transform Infrared Spectroscopy （FTIR） studies. The crystallinity of the composites and interaction among them was studied by X-ray Diffrac- tometry （XRD） and FTIR study. Maximum interaction was found in wood samples treated with MFA/DMDHEU/GP （3 phr）/MMT as shown by FTIR. Scanning Electron Microscopy （SEM） revealed the presence of polymer and MMT in the composites. Transmission Electron Microscopy （TEM） study indicated the incorporation of MMT into the wood polymer composite. Thermal stability and flammability were check.d by Thermogravimetric Analyser （TGA） and Limiting Oxygen Index （LOI） instrument. The treatment of wood with GP had a significant influence on the thermal stability and flame retardant properties of the composites. Remark.ble improvement in water repellency and chemical resistance was found for the treated wood samples. The composites showed significant improvement in mechanical properties due to treatment.

关键词： wood gum polymer nanocomposites flame retardancy

A CASE FOR SUSTAINABLE SECURITY SYSTEMS ENGINEERING:INTEGRATING NATIONAL,HUMAN,ENERGY AND ENVIRONMENTAL SECURITY

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Journal of Systems Science and Systems Engineering 2009年第4期18卷 385-402页

作者： Jason k. LEVY L. Douglas Wilder School of Government and Public Affairs Virginia Commonwealth University

In the wak. of the September 11,2001 terrorist attack., there is a growing sense of insecurity felt by many citizens around the world. Sustainable security, with roots in the sustainable development and human security literature, seek. positive transformations for the co-evolving and mutually dependent human-environmental condition by integrating （and subsuming） national, human, environmental, and energy security concems and capitalizing on opportunities provided by human creativity, diplomatic openings, modernization and environmental change. The field of Sustainable Security Systems Engineering is proposed for protecting, restoring, designing, and implementing a set of integrated natural and man-made processes that equitably and responsibly meet the biophysical needs of human communities, while maintaining long-term security, respecting financial constraints, meeting ecological limits, and improving institutional arrangements for transparent and effective governance. Scenario planning is shown to help promote sustainable security by identifying the preconditions of instability and helping to proactively address them in an increasingly complex and uncertain world. The six papers published in this featured collection cross policy domains, geographic, political, and sectoral boundaries and were discussed at forums sponsored by the Systems Engineering and Global Policy group. Collectively, they demonstrate the quality, breadth and depth of systems engineering methodologies that are used to promote sustainable security.

关键词： Sustainable security systems engineering national security human security environment and energy scenario planning

Evaporative/radiative electrospun membrane for personal cooling

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Nano Research 2023年第2期16卷 2563-2571页

作者： Mohammad Irfan Iqbal Shuo Shi Gok.la manikandan Senthil k.mar Jinlian Hu Institute of Textiles and Clothing The Hong Kong Polytechnic UniversityHong Kong 999077China Department of Biomedical Engineering City University of Hong KongHong Kong 999077China Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

Functional textiles that promote daily comfort and productivity must efficiently release body sweats and transmit radiative heat through sweat evaporation and mid-infrared radiation(MIR)(8–13μm).However,most of the traditional clothing cannot provide simultaneous sweat evaporation and mid-infrared radiation transmission efficiently,leading to a poor design of personal cooling ***,an evaporative/radiative integrated functional fibrous electrospun membrane is meticulously designed and controllably fabricated via facile electrospinning technology for personal cooling *** developed membrane can be applied as a smart wearable with distinct personal thermal management *** promising temperature and humidity responsive vapor transmission of the membrane grants 1.2 times of evaporative cooling than that of traditional ***,based on its high mid-infrared radiation transmission(53%)property in the range of 8–13μm,the as-spun membrane provides extra cooling of 1.5°C than that of ***,the building energy saving performances demonstrated that 47.1%annual building cooling can be achieved using the developed electrospun *** general,the evaporative/radiative electrospun membrane creates a passive cooling microclimate for the human body,meeting the growing demand of wearable for personal cooling.

关键词： building energy cooling management electrospinning evaporative cooling radiative cooling

Diagnosis of Leuk.mia Disease Based on Enhanced Virtual Neural Network

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Computers, Materials & Continua 2021年第11期69卷 2031-2044页

作者： k.Muthumayil S.manikandan S.Srinivasan JoséEscorcia-Gutierrez Margarita Gamarra Romany F.Mansour Department of Information Technology PSNA College of Engineering and TechnologyDindigul624622India Department of Information Technology K.Ramakrishnan College of EngineeringTiruchirappalli621112India Department of Biomedical Engineering Saveetha School of EngineeringSIMATSChennai602105India Electronic and Telecommunicacions Program Universidad Autónoma del CaribeBarranquilla08001Colombia Department of Computational Science and Electronic Universidad de la CostaCUCBarranquilla08001Colombia Department of Mathematics Faculty of ScienceNew Valley UniversityEl-Kharga72511Egypt

White Blood Cell(WBC)cancer or leuk.mia is one of the serious cancers that threaten the existence of human *** spite of its prevalence and serious consequences,it is mostly diagnosed through manual *** risk. of inappropriate,sub-standard and wrong or biased diagnosis are high in manual ***,there is a need exists for automatic diagnosis and classification method that can replace the manual *** is mainly classified into acute and chronic *** current research work.proposed a computer-based application to classify the *** the feature extraction stage,we use excellent physical properties to improve the diagnostic system’s accuracy,based on Enhanced Color Co-Occurrence *** study is aimed at identification and classification of chronic lymphocytic leuk.mia using microscopic images of WBCs based on Enhanced Virtual Neural Network.EVNN)*** proposed method achieved optimum accuracy in detection and classification of leuk.mia from WBC ***,the study results establish the superiority of the proposed method in automated diagnosis of *** values achieved by the proposed method in terms of sensitivity,specificity,accuracy,and error rate were 97.8%,89.9%,76.6%,and 2.2%,***,the system could predict the disease in prior through images,and the probabilities of disease detection are also highly optimistic.

关键词： White blood cells enhanced virtual neural network.ng segmentation feature extraction chronic lymphocytic leuk.mia