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Aerodynamic load control on a dynamically pitching wind turbine airfoil using leading-edge protuberance method

Acta mechanica Sinica 2020年第2期36卷 275-289页

作者： Y.N.Zhang m.m.Zhang C.Cai J.Z.Xu Institute of engineering Thermophysics Chinese Academy of SciencesBeijing 100190China The Key Laboratory of Wind energy Utilization of CAS Beijing 100190China University of Chinese Academy of Sciences Beijing 100049China Dalian National Laboratory for Clean energy Chinese Academy of SciencesDalian 116023China

The aerodynamic loads of wind turbine blades are substantially affected by dynamic stall induced by the variations of the angle of attack of local airfoil *** purpose of the present study is to explore the effect of leading-edge protuberances on the fluctuation of the aerodynamic performances for wind turbine airfoil during dynamic *** experimental investigation is carried out by a direct force measurement technique employing force balance at a Reynolds number Re=2×*** phase-averaged and instantaneous aerodynamic loads of the pitching airfoil,including the baseline and the wavy airfoil,are presented and *** phase-averaged results indicate that the effects of dynamic stall for the wavy airfoil can be delayed or minimized compared to the baseline airfoil,and the negative damping area of the wavy airfoil is significant decreased in full-stall *** effects of leading-edge protuberances are more notable at a higher reduced *** the instantaneous aerodynamic loads of the wavy airfoil,there is an observable reduction in fluctuations compared with baseline ***,spectral analysis is applied to quantitatively undercover the nonstationary features of the instantaneous aerodynamic *** is found that the leading edge protuberances can reduce the harmonics of the aerodynamic force signal,and enhance the stability of the aerodynamic loads under different reduced *** conclusion,leading-edge protuberances are found effective to reduce the fluctuation characteristics of the aerodynamic loads during the dynamic stall process,and help to improve the stability and prolong the service life of the wind turbine blades.

关键词： Wind turbine airfoil Dynamic stall Loads control Leading-edge protuberance Aerodynamic experiment

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Ballistic response of skin simulant against fragment simulating projectiles

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Defence Technology（防务技术） 2023年第12期30卷 70-82页

作者： Punit Kumar Pandey Atul Harmukh m.K.Khan m.A.Iqbal S.G.Ganpule Department of mechanical and Industrial engineering Indian Institute of Technology Roorkee247667India Department of Civil engineering Indian Institute of Technology Roorkee247667India Department of Design Indian Institute of Technology Roorkee247667India

The response of biological phantoms against high velocity impact is actively sought for applications in defense,space,soft robotics and *** this end,we study the ballistic response of silicone based skin simulant against fragment *** a pneumatic gas gun setup,six chisel-nosed and three regular shaped(sphere,cylinder,and cube)fragments were impacted on the skin *** resulting skin simulant response was studied in terms of ballistic limit velocities,energy densities,failure pattern,and the mechanics of *** results indicate that the shape of the fragment affects the ballistic limit *** ballistic limit velocities,energy densities of the chisel-nosed fragment simulating projectiles were relatively insensitive to the size(mass),except for the smallest(0.16 g)and largest(2.79 g)chisel-nosed *** the same size(1 g),ballistic limit velocities and failure are dependent on the shape of the *** skin simulant failed by combined plugging and elastic hole *** in the spherical fragment was dominated by the elastic hole enlargement,whereas plugging failure was dominant in all other *** spherical,cylindrical,and chisel-nosed fragments created circular cavities,and the cubical fragment created a square *** the case of the spherical fragment,slipping of the fragment within the skin simulant was *** fragments created lateral cracks emanating from the corners of the square ***,for all the fragments,the maximum deformation corresponding to the perforation was lower than the non-perforation indicating rate dependent,stress driven *** maximum deformation was also dependent on the shape of the ***,these results provide unique insights into the mechanical response of a soft simulant against ballistic *** have utility in the calibration and validation of computational models,design of personal protective equipment,and antipersonnel syste

关键词： Skin simulant Fragment Impact Ballistic limit velocity energy density Failure

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Giant hibernoma of the thoracic pleura and chest wall

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World Journal of Clinical Cases 2013年第4期1卷 143-145页

作者： Dawn e Jaroszewski Giovanni De Petris Division of Cardiothoracic Surgery Department of Surgery Mayo Clinic Arizona Phoenix AZ 85054 United States Department of Pathology Mayo Clinic Arizona Phoenix AZ 85054 United States

Hibernoma is a rare tumor containing prominent brown adipocytes that resemble normal brown *** fat(versus white fat) is predominantly found in hibernating mammals and *** fat adipocytes contain a higher number of small lipid droplets and a much denser concentration of *** tumor can occur in a variety of locations however the extremities,followed by the head and neck,have been the most common *** variants of hibernoma described have followed a benign course with the majority presenting as a small,lobulated,nontender *** present a case of a giant hibernoma arising from the pleura which invaded the intra and extra-thoracic chest.

关键词： Hibernoma Lipoma Thoracic wall Pleural neoplasm Thoracic neoplasms

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Barotropic boundary conditions and tide forcing in split-explicit high resolution coastal ocean models

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Journal of Ocean engineering and Science 2020年第3期5卷 249-260页

作者： m.Solano m.Canals S.Leonardi Naval Research Laboratory Stennis Space CenterMississippiUnited States UPRm Center for Applied Ocean Science and engineering University of Puerto RicoMayagüezPuerto Rico Caribbean Coastal Ocean Observing System MayagüezPuerto Rico Department of mechanical engineering The University of Texas at DallasTexasUnited States

A persisting problem in ocean modeling around coastal areas has been the adequate imposition of open boundary conditions,especially in the presence of complex bathymetric features commonly found in shelf *** models with horizontal resolutions of O(1 km)can generate submesoscale current variability not captured by coarser regional models which resolve mesoscale flows approximately in geostrophic and thermal-wind *** practice,higher-resolution systems will provide analyses with enhanced spatial detail but may be less skillful at predicting the evolution of mesoscale *** study aims at assessing the role of open boundary conditions,tidal forcing and tide filtering techniques in a coastal ocean model using a split-explicit time marching scheme with horizontal resolutions of O(1 km)and its effect in coastal sea level dynamics and ocean *** experiments have been performed using the Regional Ocean modeling System(ROmS)with different uniform horizontal resolution:3.6km,1.2km and *** and lateral boundary conditions are derived from the *** Oceanographic Office(NAVOCeANO)operational AmSeas model forecast,a 3.6-km resolution application of the regional Navy Coastal Ocean model(NCOm)that encompasses the Gulf of mexico and Caribbean *** conditions are interpolated from the Navy’s Coastal Ocean-Atmosphere mesoscale Prediction System(COAmPS)model with the exception of surface stresses,which are computed from a 2-km application of the Weather Research and Forecasting(WRF)model used by National Center for environmental Protection’s(NCeP)National Digital Forecast Database(NDFD).Tidal variability is imposed in two ways:1)by specifying the time evolution of sea level at the open boundaries and 2)spectrally by specifying the harmonic phases and amplitudes from the TPXO global inverse tide solutions at the ***-tidal low frequency conditions are imposed by filtering high frequencies out of the regional NCOm solut

关键词： Ocean modeling Boundary conditions Tides ROmS

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Adult Patient Doses for Chest, Skull and Lumbar Spine examinations

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Open Journal of Radiology 2015年第1期5卷 44-49页

作者： Kouther e. m. mohamadain F. I. Habbani S. m. Ibrahim Department of Physics Faculty of Science Sudan University of Scienceand Technology Khartoum Sudan Department of Physics Faculty of Science Khartoum University Khartoum Sudan Department of Physics Faculty of Science Gassim University Qassim Kingdom of Saudi Arabia

A dosimetry study for chest, skull and lumbar spine examinations in adults has been carried out at two hospitals. The aim of the study was the assessment of adult patient’s dose for chest PA, chest LAT, skull AP and lumbar spine AP examinations. The entrance Surface Dose (eSD) and the effective Dose (eD) for each examination were obtained using DoseCal software. For each examination, different results were obtained at the two hospitals. At hospital A (IFF Hospital), the total number of patients studied was 140. The mean eSD values obtained for chest PA, chest LAT, skull AP and lumbar spine AP were 0.20 mGy, 0.47 mGy, 1.25 mGy, and 1.61 mGy, respectively. At hospital B (HGB Hospital), the total number of patients studied was 369 for similar examinations and projections. The eSD values were 0.10 mGy, 0.28 mGy, 0.66 mGy and 2.47 mGy, respectively. The mean eD values at hospital A and B were 0.02 mSv and 0.01 mSv for chest PA, 0.04 mSv and 0.03 mSv for chest LAT, 0.1 mSv and 0.06 mSv for skull AP, and 0.15 mSv and 0.26 mSv for lumbar spine AP, respectively. The results were compared with the european Community Reference Levels. Although the doses were low, there was still a need for personnel training and national guidance on good practice for optimization of patients’ doses.

关键词： entrance Dose effective Dose Dose Cal Software

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enhancement of Distributed Generation by Using Custom Power Device

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Journal of electronic Science and Technology 2015年第3期13卷 246-254页

作者： Kishor V.Bhadane m.S.Ballal R.m.moharil G.H.Raisoni Institute of engineering and managem electrical Department VNIT.Nagpur and YCCE.Nagpur India

Wind energy （We） has become immensely popular for distributed generation （DG）. This case presents the monitoring, modeling, control, and analysis of the two-level three-phase We based DG system where the electric grid interfacing custom power device （CPD） is controlled to perform the smart exchanging of electric power as per the Indian grid code. We is connected to DC link of CPD for the grid integration purpose. The CPD based distributed static compensator, i.e. the distributed static synchronous compensator （DSTATCOm）, is utilized for injecting the wind power to the point of common coupling （PCC） and also acts against the reactive power demand. The novel indirect current control scheme of DSTATCOm regulates the power import and export between the We and the electric grid system. It also acts as a compensator and performs both the key features simultaneously. Hence, the penetration of additional generated We power to the grid is increased by 20% to 25%. The burden of reactive power compensation from grid is reduced by DSTATCOm. The modeling and simulation are done in mATLAB. The results are validated and verified.

关键词： Custom power device distributed generation (DG) distributed static synchronous compensator (DSTATCOm) indirect current control scheme reactive power

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effects of different planes of milk feeding and milk total solids concentration on growth,ruminal fermentation,health,and behavior of late weaned dairy calves during summer

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Journal of Animal Science and Biotechnology 2021年第4期12卷 1582-1597页

作者： R.Shiasi Sardoabi m.Alikhani F.Hashemzadeh m.Khorvash m.mirzaei J.K.Drackley Department of Animal Science College of AgricultureIsfahan University of Technology84156-83111 IsfahanIran Department of Animal Science Faculty of Agriculture and Natural ResourcesArak University38156-88349 ArakIran Department of Animal Sciences University of IllinoisUrbana 61801USA

Background:In recent years,there has been an increasing interest in using high quantities of milk or milk replacer(mR)in heat-stressed calves to alleviate the negative effects of high environmental temperatures on their ***,observations have indicated a decline in growth performance in the weaning and postweaning period,which might be optimized with increasing total solids(TS)in milk and weaning *** study aims to optimize the effects of higher quantities of milk on late weaned calves'performance by increasing TS concentration or delivery route in summer ***:Forty-eight newborn Holstein calves were used in a 2×2 factorial arrangement with the factors of preweaning total plane of milk(Pm)intake(low ***)and milk TS content(12%vs.17%).The treatments were(1)low Pm(LPm)intake with 12%TS(TS intake=45.9 kg),(2)LPm intake with 17%TS(TS intake=65.1 kg),(3)high Pm(HPm)intake with 12%TS(TS intake=63.7 kg);and(4)HPm intake with 17%TS(TS intake=90.3 kg).Calves were weaned at d 83,and the study was terminated at d 103 of *** data(every 10 day),skeletal growth(d 80 and 100),ruminal fermentation parameters(d 48 and 91),and behavioral measurements(d 69,70,93 and 94)were analyzed as repeated measurements with PROC mIXeD of SAS 9.4(SAS Institute Inc.,Cary,NC).Results:Calves receiving HPm consumed less PmR from d 44 to 83 of age,but they had higher ADG from d 24 to 53 of age compared to those fed LPm(Pm×age,Pes receiving milk with 17%TS had lower PmR intake from d 14 to 83 of age,but greater ADG from d 34 to 53 compared to those receiving milk with 12%TS(TS×age,Pes that received HPm had greater skeletal growth parameters compared to LPmfed calves,with a similar effect evident for calves fed milk with 17%TS compared with those fed milk with 12%*** receiving milk with 17%TS had greater fecal scores and diarrhea occurrence than those fed milk with 12%TS in HPm,but not ***:Increasing Pm

关键词： Dairy calf milk feeding level Pre-weaning Total solids

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Toward an understanding of dwell fatigue damage mechanism of bimodal Ti-6Al-4V alloys

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Journal of materials Science & Technology 2022年第13期108卷 244-255页

作者： L.R.Zeng L.m.Lei X.m.Luo G.P.Zhang Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of mechanical engineering Chengdu UniversityChengdu 610106China AeCC Shanghai Commercial Aircraft engine manufacturing Co. Ltd.Shanghai 201306China

Dwell fatigue effect is a long-standing problem threatening the long-term service reliability for fan blades and fan disks of an aircraft *** understand the basic mechanism of dwell fatigue damage,pure fatigue and 60 s dwell fatigue properties of bimodal Ti-6Al-4V alloys with different volume fractions of the primaryα(α_(p))phase were examined *** results showed that both pure fatigue and dwell fatigue life decreased with increasing the volume fraction of theα_(p)phase and the dwell fatigue life was lower than the pure fatigue *** quasi-in-situ test results and the quantitative characterization of damage behaviors of the local microstructure units defined by theα_(p)-secondaryα(α_(s))combination reveal that theα_(s)phase close to theα_(p)phase with extensively slip activities was gradually damaged under dwell fatigue loading,while that under pure fatigue loading was undamaged,demonstrating that the dwell loading induced the damage of theα_(s)phase,and further reduced the fatigue life.A stress relaxation-based model is proposed to describe the physical mechanism on dwell fatigue damage of the bimodal Ti-6Al-4V alloy,*** elastic deformation of theα_(s)phase caused by the strain incompatibility would be gradually transformed into plastic deformation during the dwell stage,and thus promotes fatigue *** model provides new insights into the microscopic process of stress/strain transfer between the soft and hard microstructure units under dwell fatigue loading.

关键词： Dwell effect Fatigue damage Stress relaxation Volume fraction of primaryαphase Quasi-in-situ testing

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Thermal Tempering Does Not Impact Rainbow Trout and Brown Trout Survival

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Advances in Bioscience and Biotechnology 2020年第7期11卷 345-353页

作者： Nathan Huysman Jill m. Voorhees eric Krebs michael e. Barnes South Dakota Department of Game Fish and Parks McNenny State Fish Hatchery Spearfish SD USA

Hatchery-reared fish are frequently adjusted (tempered) to the higher water temperatures present in the water bodies where they are to be stocked. This study was undertaken to determine the necessity of such tempering practices. This study used rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) reared at 11.2°C. The first two trials for each species were designed to simultaneously determine the upper incipient lethal temperature and 100% lethal temperature over a 14-day period. The third trial for each species evaluated the effects of an exaggerated 12-hour tempering regime on fish survival after placement in elevated water temperatures. After transfer from a water temperature of 11.2°C, no rainbow trout survived at 26°C, and only 50% survived at 25°C. No brown trout survived at 22°C and only 50% at 20°C. Survival of rainbow trout was not improved by the 12-hour tempering regime where water temperatures were slowly increased from 11.2°C to either 25°C or 26°C. Similarly, tempering did not improve brown trout survival at either 20°C or 22°C. These results suggest that tempering is not needed when hatchery-reared trout are reared and stocked at the water temperatures within the range of those used in this study.

关键词： Tempering Rainbow Trout Oncorhynchus mykiss Brown Trout Salmo trutta Temperature

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Smart computing approach for design and scale-up of conical spouted beds with open-sided draft tubes

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Particuology 2021年第2期19卷 179-190页

作者： m.Karimia B.Vaferi S.H.Hosseini m.Olazar S.Rashidi Laboratory of Separation and Reaction engineering(LSRe) Associate Laboratory(LSRE/LCM)Department of Chemical EngineeringFaculty of EngineeringUniversity of PortoRua Dr.Roberto FriasS/N4099-002 PortoPortugal Department of Advanced Calculations ChemicalPetroleumand Polymer Engineering Research CenterShiraz BranchIslamic Azad UniversityShirazIran Department of Chemical engineering Ilam UniversityIlam 69315-516Iran Department of Chemical engineering University of the Basque Country UPV/EHUP.O.Box 644E48080 BilbaoSpain Department of Petroleum engineering Omidiyeh BranchIslamic Azad UniversityOmidiyehIran

Open-sided draft tubes provide an optimal gas distribution through a cross flow pattern between the spout and the annulus in conical spouted *** design,optimization,control,and scale-up of the spouted beds require precise information on operating and peak pressure *** this study,a multi-layer perceptron(mLP)neural network was employed for accurate prediction of these hydrodynamic characteristics.A relatively huge number of experiments were accomplished and the most influential dimensionless groups were extracted using the Buckingham-pi ***,the dimensionless groups were used for developing the mLP model for simultaneous estimation of operating and peak pressure *** iterative constructive technique confirmed that 4-14-2 is the best structure for the mLP model in terms of absolute average relative deviation(AARD%),mean square error(mSe),and regression coefficient(R^(2)).The developed mLP approach has an excellent capacity to predict the transformed operating(mSe=0.00039,AARD%=1.30,and R^(2)=0.76099)and peak(mSe=0.22933,AARD%=11.88,and R2=0.89867)pressure drops.

关键词： Conical spouted beds Open-sided draft tubes Operating pressure drops Peak pressure drop Smart modeling Design guidelines

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