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Scattering of water waves by a wave energy device consisting of a pair of co-axial cylinders in a uniform water having finite channel width

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Journal of Ocean Engineering and Science 2021年第3期6卷 276-284页

作者： p.Borah m.Hassan Department of mathematics North Eastern Regional Institute of Science and TechnologyItanagarArunachal Pradesh 791109India

We consider a device which consists of a floating structure over a cylindrical plate placed at a finite height from the impermeable ocean *** paper developes the interaction of linear water waves with such a *** whole fluid domain is divided into a number of sub-domains and boundary value problems are formulated for each identified *** channel multipoles,separation of variables and matched eigenfunction expansion methods allow us to solve boundary value problems for the diffracted velocity potentials in each *** investigate the wave forces exerted on the proposed ***,the effects of the various parameters,e.g.,drafts,radii,the gap between the cylinders and mainly channel width of the device on the wave forces exerted by the cylinders are presented *** observe a small oscillation nature near the peak value of the exciting force for the particular value of channel width w=*** peak value of the exciting forces occurs near the wavenumber kr 1=1.0 for different width of the channel *** obtained results are compared with some available results,and it shows a good agreement between the obtained and available results.

关键词： Water waves Exciting force Channel multipoles Channel width Wavenumber,2000 mSC 76B07 76B15.

Spectral Characterization of Laser Induced plasma from Titanium Dioxide

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plasma Science and Technology 2007年第4期9卷 456-459页

作者： V.J.DANN m.V.mATHEW V.p.N.NAmpOORI C.p.G.VALLABHAN V.m.NANDAKUmARAN p.RADHAKRISHNAN International School of photonics Cochin University of Science and TechnologyCochin 22India Centre of Excellence in Lasers and Optoelectronic SciencesCochin University of Science and TechnologyCochin 22India International School of photonics Cochin University of Science and TechnologyCochin 22India Centre of Excellence in Lasers and Optoelectronic Sciences Cochin University of Science and TechnologyCochin 22India

Optical emission from TiO2 plasma, generated by a nanosecond laser is spectroscopically analysed. The main chemical species are identified and the spatio-temporal distribution of the plasma parameters such as electron temperature and density are characterized based on the study of spectral distribution of the line intensities and their broadening characteristics. The parameters of laser induced plasma vary quickly owing to its expansion at low background pressure and the possible deviations from local thermodynamic equilibrium conditions are tested to show its validity.

关键词： laser induced plasma titanium dioxide optical emission spectroscopy local thermodynamic equilibrium

Adaptively Controlled Hybrid Welding Using a High Brightness Laser

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稀有金属材料与工程 2011年第S4期40卷 1-5页

作者： C.m.Allen p.A.Hilton TWI Ltd Granta ParkGreat AbingtonCambridgeCB21 6ALUnited Kingdom

Hybrid laser-mAG welding with real-time adaptive control has been *** welding conditions have been developed to produce ISO 13919-1 class B (stringent) quality butt welds between 8mm thickness steel plates,using a 5kW *** Yb fibre laser combined with conventional arc welding equipment.A laser vision seam tracking system has enabled a 7-axis robot,manipulating the hybrid welding head,to track butt joints in real time during *** laser vision system has also provided information on the variations in joint fit-up,in particular the width of any gaps,or height of any mismatches *** information has then been used to automatically adjust the robot position or speed,or arc welding parameters,depending on the fit-up *** this way,the tolerance of the hybrid process has been augmented,producing stringent quality welds over a wider range of joint fit-up cases than when using fixed conditions alone.

关键词： hybrid welding steel adaptive control fit-up tolerance

Use of two fungal species to induce agarwood resin formation in Gyrinops walla

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Journal of Forestry Research 2019年第2期30卷 721-726页

作者： S.m.C.U.p.Subasinghe H.I.D.Hitihamu K.m.E.p.Fernando Department of Forestry and Environmental Science University of Sri Jayewardenepura Department of Botany University of Sri Jayewardenepura

Gyrinops walla Gaertn. is the only species growing in Sri Lanka that belongs to the agarwood family,Thymelaeaceae. Although agarwood resin induction and extraction from Aquilaria species of the same family have been practised for many decades in Southeast Asian region,the ability of producing agarwood resins in G. walla was discovered recently. Since previous studies were on agarwood resins formed due to natural causes, the present study was conducted to identify the potential fungal species that are capable of artificially inducing agarwood resin formation in G. walla. Since this is the first ever study conducted on artificial inducement of agarwood resin formation in ***, Aspergillus niger and Fusarium solani were selected owing to their high abundance in the naturally formed agarwood resinous tissues collected from 25 G. walla *** fungal species were separately grown in yeast extract glucose agar and used to inoculate healthy G. walla trees under aseptic conditions. Three holes were made for each tree and 2 g of fungal culture including the medium were placed in each hole. Tissue discoloration, characteristic aroma, resin content and resin constituents were checked at10 cm intervals above and below the inoculation points for a period of 1 year. Results revealed that tissue discoloration and resin content were higher in the trees inoculated with A. niger. Other than at 10 cm above and below the inoculation points, samples collected at all locations had significantly higher resin contents when inoculated with A. niger compared to F. solani. Sixteen agarwood resin constituents, which were also recorded in Aquilaria species, were identified from the discolored tissues using GC–mS analysis. Jinkohol, agarospirol and 2(2-phenyl)chromone derivatives were found in all discolored tissues collected at 10-cm intervals of the trees inoculated with both fungi. b-Seline, c-eudesmol and valerenal were found in nine of 10 sample points on the stem. c-Elemene was recor

关键词： Gyrinops walla Agarwood resin Aspergillus niger Fusarium solani Inoculation

A compliant polymorphing wing for small UAVs

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Chinese Journal of Aeronautics 2020年第10期33卷 2575-2588页

作者： Sadique p.mUHAmmED Rafic m.AJAJ Kamran AKHAN Department of mechanical Engineering United Arab Emirates UniversityAl Ain 15551United Arab Emirates Department of Aerospace Engineering Khalifa University of Science and TechnologyAbu Dhabi 127788United Arab Emirates

This paper presents the development of a novel compliant polymorphing wing capable of chord and camber morphing for small *** morphing wing can achieve up to 10%chord extension and±20°camber *** design,modeling,sizing,manufacturing and mechanical testing of the wing are *** polymorphing wing consists of one continuous front spar fixed to the fuselage and a rear spar on each side of the *** rear spar can translate in the chordwise direction(chord morphing)and rotate around itself(camber morphing).A flexible elastomeric latex sheet is used as the skin to cover the wing and maintain its aerodynamic shape whilst allowing *** loads from the skin are transferred to the spars using the compliant cellular ribs that support the flexible skin and facilitate ***-tensioning is applied to the skin to minimize wrinkling when subject to aerodynamic and actuation loads.A rack and pinion actuation system,powered by stepper motors,is used for ***-structural design,analysis and sizing are *** comparison between the polymorphing wing and the baseline wing(non-morphing)shows that chord morphing improves aerodynamic efficiency at low angles of attack while camber morphing improves efficiency at high angles of attack.

关键词： Camber morphing Chord morphing Compliant structures Flexible skin UAVs

Cold-Sprayed magnesium Coatings Deposited with Helium and Air

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稀有金属材料与工程 2012年第S1期41卷 61-63页

作者： m p planche R Bolot C Coddet LERmpS University of Technology of Belfort-Monbeliard90010Belfort cedexFrance

Cold-sprayed magnesium coatings have been little researched although cold spraying has been applied to deposit a large number of materials such as metals,metal matrix *** the present study,helium gas and air were employed as the propelling gases to deposit mg coatings under the temperature of 600℃and 630℃.The effect of gas types on the coating microstructure was *** is much interesting to find that the particle deposition efficiency using helium gas as propelling gas is lower than that using *** suggests that strong erosion occurred during cold spraying using helium *** porosity of the coating using helium gas is lower than that using *** addition,the in-flight particle velocity was also simulated by the FLUENT software to explore the effect of gas *** modeled results show that the in-flight particle velocity using helium is higher than the erosion velocity of mg particle.

关键词： cold spraying magnesium coating microstructure particle velocity electrochemical cell

Numerical simulation of high speed reacting shear layers using AUSm+-up scheme-based unstructured finite volume method solver

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International Journal of modeling, Simulation, and Scientific Computing 2017年第3期8卷 39-60页

作者： m.Deepu m.p.Dhrishit S Shyji Department of Aerospace Engineering Indian Institute of Space Science and Technology Thiruvananthapuram KeralaIndia-695547 Department of mechanical Engineering SCT College of Engineering Thiruvananthapuram KeralaIndia-695018

Development of an Advection Upstream Splitting method(AUSm+-up)scheme-based Unstructured Finite Volume(UFVm)solver for the simulation of two-dimensional axisymmetric/planar high speed compressible turbulent reacting shear layers is *** inviscid numerical flux is evaluated using AUSm+-up upwind *** eight-step hydrogen–oxygen finite rate chemistry model is used to model the development of chemical species in a supersonic reacting flow *** chemical species terms are alone solved implicitly in this explicit flow solver by rescaling the equation in *** turbulence modeling has been done using RNG-based k–***-stage Runge–Kutta method has been used for explicit time *** nonreacting twodimensional Cartesian version of the same solver has been successfully validated against experimental and numerical results reported for the wall static pressure data in sonic slot injection to supersonic *** validation studies for reacting flow solver has been done using experimental results reported for a coaxial supersonic combustor,in which species profile at various axial locations has been *** numerical solver is useful in simulating combustors of high speed air-breathing propulsion devices.

关键词： Supersonic combustion turbulent reacting flows advection upstream splitting method

Comparison between radarsat-1 SAR different data modes for oil spill detection by a fractal box counting algorithm

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International Journal of Digital Earth 2009年第3期2卷 237-256页

作者： m.marghany A.p.Cracknell m.Hashim Natural Tropical Resources Information&mapping Research Group(NATRIm Research Group) Faculty of Geoinformation Science and EngineeringUniversiti Teknologi Malaysia81310 UTMSkudaiJohore BahruMalaysia Department of Remote Sensing Faculty of Geoinformation Science and EngineeringUniversiti Teknologi Malaysia81310 UTMSkudaiJohore BahruMalaysia

This work presents a modified formula for the fractal box counting *** method is based on the utilisation of the probability distribution formula in the fractal box *** purpose of this method is to use it for the discrimination of oil spill areas from the surrounding features,*** surface and look-alikes,using RADARSAT-1 SAR Wide beam mode(W1),Standard beam mode(S2)and Standard beam mode(S1)data acquisition under different wind *** results show that the new formula is able to discriminate between oil spills and look-alike *** results also illustrate that the new fractal formula identifies well the deficiency of oil spills in pairs of S2 ***,there are no significant differences between fractal values of look-alikes,low wind zone,and current shear features in different beam modes for acquisition of RADARSAT-1 SAR *** W1 mode data,however,show an error standard deviation of 0.002,thus performing a better discrimination of oil spills than the S1 and S2 mode data.

关键词： RADARSAT-1 SAR oil spill look-alike low wind zone fractal dimension

Incipient motion of gravel in a bottomless arch culvert

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International Journal of Sediment Research 2011年第1期26卷 15-26页

作者： B.m.CROOKSTON B.p.m.TULLIS Utah State University 8200 Old Main HillLoganUT 84322

Incipient motion was investigated for four gravel substrate materials in a bottomless arch culvert and a rectangular *** methods for calculating Shields parameter at incipient motion（θc） based upon local flow parameters were *** incipient motion region for bottomless arch culverts in fully turbulent flow was defined with two bounding curves on Shields *** variation ofθcas a function of relative roughness was ***,a method that utilizes measured flow velocities to determine stable substrate particle diameters for bottomless arched culverts is presented as an alternative to the Shields diagram.

关键词： Incipient motion Bottomless arch culvert Shields parameter Flow rate Experiment