http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
D. Vasanth Kumar,D. Raja 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3
In this research work, it is proposed to study the thermal comfort properties of socks made from virgin cotton andrecycled polyester fibres and its blends. To determine the thermal comfort properties of socks the following parameters suchas thermal conductivity, thermal resistance, air permeability and relative water-vapour permeability has to be investigated. Amongst the blends, higher the addition of recycled polyester content results in increased air permeability, thermal resistanceand relative water-vapour permeability and decreased thermal conductivity values than the virgin cotton blends. Furthermore,it is noticed that recycled polyester ratio increases among the blends the fabric become thin, lighter and more porous withbetter thermal resistance, air permeability, relative water-vapour permeability and lesser thermal conductivity than the virgincotton ratio in the blends. It is suggested that modifications in the fibre blends lead to changes in the fabric properties such asthickness which in turn affects the comfort properties of socks. The findings were statistically evaluated by analysis ofvariance (ANOVA) by using SPSS 15.0. Statistical result analysis also reveals that the blend ratio significantly affects all ofthe thermal comfort properties of the socks.
D. Elil Raja,S. Prathap Singh,V. Rangarajan,M. Chrispin Das 한양대학교 청정에너지연구소 2022 Journal of Ceramic Processing Research Vol.23 No.6
Ultrasonic assisted stir casting was used to fabricate aluminium based metal matrix composite reinforcement with 4% copperand various combinations (0, 1 or 2 wt.%) of aluminium oxide. In this study, Taguchi Grey Relational Analysis (GRA) wasused to optimise the wear behaviour of the metal matrix composite reinforcement. Reinforcing elements were visualised usingSEM, which shows that a uniform distribution is possible with just 1% aluminium oxide additions. In order to betterunderstand the association between wear factors such as sliding distance, sliding speed and applied load, we looked at the wearrate and friction coefficient. According to the Taguchi L9 orthogonal array, we conducted the trials. In each experiment, therate of wear as well as the coefficient of friction were measured. If you apply a force of 10 N, slide at 1 m/s for 1500 metres,the Taguchi GRA concluded that this was the best combination for your experiment. There is a 61 percent correlation betweenthe sliding velocity and composite wear. After all was said and done, the most well-worn surface was found to have the fewestscratches and fine grooves.
Daniel, D. Joseph,Raja, A.,Kim, H.J.,Ramasamy, P. Elsevier 2018 OPTIK -STUTTGART- Vol.158 No.-
<P><B>Abstract</B></P> <P>In this paper, we present an environment friendly hydrothermal process to synthesize nano/sub micro particles of the rare earth activated complex fluoride NaMgF<SUB>3</SUB> at 180 °C. The tittle compound synthesis was carried out at elevated pressure and temperature in an aqueous medium. The powder X-ray diffraction pattern was recorded to check the phase purity of the synthesised compound. Synthesized compounds were micro and nanocrystalline with orthorhombic perovskite crystal structure, space group Pcmn. In order to identify the functional groups Fourier Transform Infrared spectral analysis have been performed. The size and shape of the synthesised compounds were studied by using Field Emission - Scanning Electron Microscope images. Chemical composition of the synthesised compounds were checked by the energy - dispersive X-ray spectra. The absorption bands around 220 and 270 nm were observed which is corresponding to the electronic transition between 4f and 5d configuration of Ce<SUP>3+</SUP>. Photoluminescence emission related to the 5 d → 4 f transitions in Ce<SUP>3+</SUP> was observed at 324 nm. Thermoluminescence properties were studied for the X-ray irradiated samples. The glow curve kinetic parameters of activation energy (E) and frequency factor (S) were calculated using standard methods.</P>
Dwarakanathan, D.,Ramkumar, R.,Raja, S.,Rao, P. Siva Subba Techno-Press 2015 Advances in aircraft and spacecraft science Vol.2 No.3
A design methodology is presented to develop the hingeless control surfaces for MAV using adhesively bonded Macro Fiber Composite (MFC) actuators. These actuators have got the capability to deflect the trailing edge surfaces of the wing to attain the required maneuverability, besides achieving the set aerodynamic trim condition. A scheme involving design, analysis, fabrication and testing procedure has been adopted to realize the trailing edge morphing mechanism. The stiffness distribution of the composite MAV wing is tailored such that the induced deflection by piezoelectric actuation is approximately optimized. Through ground testing, the proposed concept has been demonstrated on a typical MAV structure. Electromechanical analysis is performed to evaluate the actuator performance and subsequently aeroelastic and 2D CFD analyses are carried out to see the functional requirements of wing trailing edge surfaces to behave as elevons. Efforts have been made to obtain the performance comparison of conventional control surfaces (elevons) with morphing wing trailing edge surfaces. A significant improvement in lift to drag ratio is noticed with morphed wing configuration in comparison to conventional wing. Further, it has been shown that the morphed wing trailing edge surfaces can be deployed as elevons for aerodynamic trim applications.
Wind Tunnel Studies on Autonomous Hybrid VTOL UAV with Wing Morphing Technology
Raja S,Shanmugam Palaniswamy,Dwarakanathan D,Parammasivam K M 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10
CSIR-NAL has designed VTOL winged UAV to address hybrid unmanned vehicle requirements. The hybrid UAV’s aerodynamics and propulsion characteristics have been validated through wind tunnel test and to achieve better flight performance, a morphing wing technology was developed using multi-axis robotic concept. The multi axis controller was realized for the morphed wing mechanism of VTOL UAV through LMA and PID controller. The control motion simulation was performed in MATLAB. The experimental results were obtained on a typical UAV morphing wing travel in multi-axis with a dedicated test rig. The controller successfully detected the IMU sensors and adopted with APM (Autopilot mode) instrumentation, simulating the flight condition. The controller with the Robotic Coupling System for WTT was operationalized at NAL’s MART Tunnel facility. This approach generates a simple model with a relatively high degree of accuracy, which can be easily integrated on to the wind tunnel tested hybrid UAV to develop high performance all terrain capable VTOL vehicles.
( Mangesh D. Pustode ),( Bhupendra Dewangan ),( V. S. Raja ),( Neeta Paulose ),( Narendra Babu ) 한국부식방식학회(구 한국부식학회) 2016 Corrosion Science and Technology Vol.15 No.5
DC potential drop technique was employed during the slow strain rate tests to study the hot salt stress corrosion crack (HSSCC) initiation at 300 and 400 °C. Threshold stresses for HSSCC initiation were found to about 88 % of the yield strength at both temperatures, but the time from crack initiation to final failure (Δtscc) decreased significantly with temperature, which reflects larger tendency for brittle fracture and secondary cracking. The brittle fracture features consisted of transgranular cracking through the primary α grain and discontinuous faceted cracking through the transformed β grains.
KARTHIKEYAN, K.,RAJA, D. SENTHIL,SUNDARARAJAN, P. The Korean Society for Computational and Applied M 2022 Journal of applied mathematics & informatics Vol.40 No.1-2
We study the existence and uniqueness of solutions for a class of boundary value problems of nonlinear fractional order differential equations involving the Caputo fractional derivative by employing the Banach's contraction principle and the Schauder's fixed point theorem. In addition, an example is given to demonstrate the application of our main results.
Jang, K.,Raja, J.,Kim, J.,Lee, Y.,Kim, D.,Yi, J. IET 2013 Electronics letters Vol.49 No.16
<P>The influence of carrier concentration and oxygen vacancy on the performance of amorphous-indium¿tin¿zinc-oxide (a-ITZO) thin-film transistors (TFTs) is reported. The ITZO TFT with lowest carrier concentration and oxygen vacancy has a high field-effect mobility (μ<SUB>FE</SUB>) of 37.2 cm<SUP>2</SUP>/V.s, a high on/off current ratio (I<SUB>ON/OFF</SUB>) of ˜1 × 10<SUP>7</SUP> and a low subthreshold swing (SS) of 0.93 V/decade. By increasing the carrier concentration and oxygen vacancy, μ<SUB>FE</SUB>, ION/OFF and SS were surprisingly degraded to 14.4 cm2/V.s, ˜4 × 10<SUP>4</SUP> and 4.01 V/decade, respectively. By controlling the carrier concentration and oxygen vacancies of ITZO bulk, improvement of the performance in TFT devices can be achieved. The proposed high μFE of 37.2 cm2/V.s is enough for the application of next-generation displays requiring ultra-high resolution and high-frame-rate displays.</P>
Donaghey, Jenny E.,Ashraf, Raja Shahid,Kim, Youngju,Huang, Zheng Gang,Nielsen, Christian B.,Zhang, Weimin,Schroeder, Bob,Grenier, Christophe R. G.,Brown, Christopher T.,D'Angelo, Pasquale,Smith, Jerem Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.46
<P>The synthesis of the novel electron-rich pyrroloindacenodithiophene (NIDT) unit is reported. Stille copolymerization of the distannylated NIDT unit, with the electron-deficient dibrominated benzothiadiazole (BT), difluorobenzothiadiazole (ffBT), thienopyrrolodione (TPD) and 1,1′-bithienopyrrolodione (biTPD) units afforded a series of low band gap semiconducting polymers. Initial testing shows promise for the use of these materials as p-type semiconductors in organic field effect transistors (OFETs) with mobilities as high as 0.07 cm<SUP>2</SUP>V<SUP>−1</SUP>s<SUP>−1</SUP> being measured. These materials have also been tested as the donor polymer in polymer/fullerene bulk heterojunction organic photovoltaics (OPVs) giving maximum efficiencies of 2.5%.</P> <P>Graphic Abstract</P><P>Four copolymers synthesized with a novel unit, pyrroloindacenoditiophene, were tested in OFET (μ<SUB>max</SUB> 0.07 cmV<SUP>−1</SUP>s<SUP>−1</SUP>) and OPV (η<SUB>max</SUB> 2.5%) devices. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm13428k'> </P>
Random benzotrithiophene-based donor–acceptor copolymers for efficient organic photovoltaic devices
Nielsen, Christian B.,Ashraf, Raja Shahid,Schroeder, Bob C.,D’Angelo, Pasquale,Watkins, Scott E.,Song, Kigook,Anthopoulos, Thomas D.,McCulloch, Iain The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.47
<P>A series of benzotrithiophene-containing random terpolymers for polymer solar cells is reported. Through variations of the two other components in the terpolymers, the absorption profile and the frontier energy levels are optimized and maximum power conversion efficiencies are nearly doubled (5.14%) relative to the parent alternating copolymer.</P> <P>Graphic Abstract</P><P>A series of benzotrithiophene-containing random terpolymers show greatly improved efficiencies in organic photovoltaic devices compared to the parent alternating copolymer. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc31934a'> </P>