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Rayleigh Waves Propagation in an Infinite Rotating Thermoelastic Cylinder

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Computers, materials & Continua 2021年第5期67卷 2515-2525页

作者： A.m.Farhan Department of Physics Faculty of ScienceJazan UniversityJazanSaudi Arabia Department of Physics Faculty of ScienceZagazig UniversityZagazigEgypt

In this paper,we investigated the inuence of rotating half-space on the propagation of Rayleigh waves in a homogeneous isotropic,generalized thermo-elastic body,subject to the boundary conditions that the surface is traction *** addition,it is subject to insulating thermal conduction.A general solution is obtained by using Lame’potential’s and Hankel *** dispersion equations has been derived separately for two types of Rayleigh wave propagation properties by solving the equations of motion with appropriate boundary *** is observed that the rotation,frequency and r exert some influence in the homogeneous isotropic medium due to propagation of Rayleigh *** frequency equation has been derived of homogeneous properties by solving the equations of motion with appropriate boundary *** has been found that the frequency equation of waves contains a term involving the ***,the phase velocity of Rayleigh waves changes with respect to this *** the rotating vanishes,the derived frequency equation reduces to that obtained in classical generalized thermo-elastic case which includes the relaxation time of heat *** order to illustrate the analytical development,the numerical solution is carried out and computer simulated results in respect of Rayleigh wave velocity and attenuation coefficient are presented graphysically.A comparative and remarkable study has been carried out through various graphs to deliberate the consequences of different parameter on the frequency *** obtained results can be very useful in the design and optimization of Rayleigh wave.

关键词： Rayleigh waves wave propagation generalized thermoelasticity thermal stress rotation

Using compositional data analysis to explore accumulation of sedentary behavior,physical activity and youth health

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Journal of sport and Health science 2022年第2期11卷 234-243页

作者： simone J.J.m.Verswijveren Karen E.Lamb Josep A.martín-Fernández Elisabeth Winkler Rebecca m.Leech Anna Timperio Jo salmon Robin m.Daly Ester Cerin David W.Dunstan Rohan m.Telford Richard D.Telford Lisa s.Olive Nicola D.Ridgers Institute for Physical Activity and Nutrition School of Exercise and Nutrition SciencesDeakin UniversityGeelongVIC 3216Australia melbourne school of Population and Global Health University of MelbourneParkvilleVIC 3053Australia Department of Computer science Applied Mathematics and StatisticsUniversity of GironaGirona 17003Spain school of Public Health University of QueenslandHerstonQLD 4006Australia mary macKillop Institute for Health Research Australian Catholic UniversityFitzroyVIC 3065Australia school of Public Health University of Hong KongHong KongChina Baker Heart and Diabetes Institute MelbourneVIC 3004Australia Research Institute for sport and Exercise University of CanberraBruceACT 2617Australia school of Psychology Deakin UniversityBurwoodVIC 3125Australia ImPACT Research Institute Deakin UniversityBurwoodVIC 3125Australia ANU medical school Australian National UniversityGarranACT 2605Australia

Purpose:The study aimed to describe youth time-use compositions,focusing on time spent in shorter and longer bouts of sedentary behavior and physical activity(PA),and to examine associations of these time-use compositions with cardiometabolic ***:Accelerometer and cardiometabolic biomarker data from 2 Australian studies involving youths 7-13 years old were pooled(complete cases with accelerometry and adiposity marker data,n=782).A 9-component time-use composition was formed using compositional data analysis:time in shorter and longer bouts of sedentary behavior;time in shorter and longer bouts of light-,moderate-,or vigorous-intensity PA;and"other time"(i.e.,non-wear/sleep).shorter and longer bouts of sedentary time were defined asmin and>5 min,*** bouts of light-,moderate-,and vigorous-intensity PA were defined asmin;longer bouts were defined as≥1 *** models examined associations between overall time-use composition and cardiometabolic ***,associations were derived between ratios of longer activity patterns relative to shorter activity patterns,and of each intensity level relative to the other intensity levels and"other time",and cardiometabolic ***:Confounder-adjusted models showed that the overall time-use composition was associated with adiposity,blood pressure,lipids,and the summary ***,more time in longer bouts of light-intensity PA relative to shorter bouts of light-intensity PA was significantly associated with greater body mass index z-score(zBmI)(β=1.79;sE=0.68)and waist circumference(β=18.35,sE=4.78).When each activity intensity was considered relative to all higher intensities and"other time",more time in light-and vigorous-intensity PA,and less time in sedentary behavior and moderate-intensity PA,were associated with lower waist ***:Accumulating PA,particularly light-intensity PA,in frequent short bursts may be more beneficial for limiting adi

关键词： Accumulation patterns Cardiometabolic health Children Compositional data analysis Time-use

Toluidine Blue O-Gelatin Gel Dosimeter for Radiation Processing

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Open Journal of Polymer Chemistry 2014年第3期4卷 56-61页

作者： s. m. Gafar m. A. El-Kelany m. A. El-Ahdal s. R. El-shawadfy National Center for Radiation Research and Technology AEA Cairo Egypt

In this study the spectrophotometric response of the Toluidine Blue O (TBO)-gelatin gel dosimeter irradiated with gamma rays was characterized. Preparation of dyed-gelatin gel takes place in neutral medium;to give eventually gel dosimeter has a sharp absorbance peak at 635 nm that bleaches quantitatively upon irradiation and the colour change can be measured with UV-VIs spectrophotometer. The useful dose range was 1 - 150 Gy. The radiation chemical yield (G-value) of gel dosimeter was calculated and found to increase by increasing concentration of dye. Post-irradiation storage on the response of gel is discussed. The dose response function, radiation sensitivity, and dependences of the response on environmental factors were studied.

关键词： Gel Toluidine Blue O Dosimeter γ Rays and Low Dose

study　on　Friction　Factor　of　Developing　and　Developed　Laminnr　Flow　in　Annular－sector　Ducts

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Journal of Thermal science 1995年第3期4卷 180-184页

作者： m.J. Lin W.Q. Tao (school of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, shabby 710049, China)s.s. Lue (Institute of Chemical Engineering, southern-China University of science and Technology, Guangzhou,Guangdong, China) school of Energy and Power Engineering Xi’an Jiaotong University Xi’an China Institute of Chemical Engineering Southern-China University of Science and Technology Guangzhou China

The pressure drops of laminar developing and developed flow in Hnnular-sector ducts with small round corner have been investigated experimentally. Numerical simulation has been performed to study the effect of the small round corner on the friction factor in the developed region. It has been found that with the increase in corner radius, the value of fRe decreases. In the range of rc/ro from 0.031 to 0.12,the decrease in fRe varies from 0.048% to 0.1% for the five apex angle computed.

关键词： laminar flow friction factor.

Improvement in mechanical and Thermo-mechanical Properties of Epoxy Composite Using Two Different Functionalized multi-Walled Carbon Nanotubes

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Open Journal of Composite materials 2013年第2期3卷 1-9页

作者： m. B. A. salam m. V. Hosur s. Zainuddin s. Jeelani mechanical Engineering Tuskegee University Tuskegee USA

In this study, two types of functionalized multi-walled carbon nanotubes were dispersed in an epoxy resin system (sC-15) at room and elevated temperatures using a combination of sonication and high shear mixing methods to determine optimal mechanical and thermal properties. At first, 0.1 wt% - 0.3 wt% of amino-functionalized multi-walled carbon nanotubes (mWCNT-NH2) and carboxyl-functionalized multi-walled carbon nanotubes (mWCNT-COOH) were dispersed in part-A of sC-15 resin using a combination method. The mixture was then added to part-B of epoxy resin and cured using two different cycles (cycle A: at room temperature for 24 hours and post-cure at 93.33?C for 4 hours, cycle B: at 65.56?C for 5 hours). In addition, control samples (without mWCNTs) were also fabricated for baseline consideration under similar conditions. In all cases, epoxy with mWCNTs showed improved performance. Improvements in properties in mWCNT/epoxy samples prepared using cycle A were comparatively lower than samples prepared with cycle B. Flexural and thermo-mechanical results demonstrated maximum improvement in 0.2 wt% mWCNT-COOH modified epoxy samples prepared using cycle B. Improvements in performance for samples cured at elevated temperatures were attributed to better dispersion of mWCNTs due to reduced viscosity. On the other hand, increased number of functional groups present in mWCNT-COOH contributed to higher crosslinking resulting in the highest observed properties.

关键词： Carbon Nanotubes Functionalization Flexure storage modulus Glass Transition Temperature

Biogeography-Based Combinatorial strategy for Efficient Autonomous Underwater Vehicle motion Planning and Task-Time management

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Journal of marine science and Application 2016年第4期15卷 463-477页

作者： s.m.Zadeh D.m.WPowers K.sammut A.m.Yazdani Centre for maritime Engineering Control and Imaging School of Computer Science Engineering and Mathematics Flinders University Adelaide SA 5042 Australia

Autonomous Underwater Vehicles （AUVs） are capable of conducting various underwater missions and marine tasks over long periods of time. In this study, a novel conflict-free motion-planning framework is introduced. This framework enhances AUV mission performance by completing the maximum number of highest priority tasks in a limited time through a large-scale waypoint cluttered operating field and ensuring safe deployment during the mission. The proposed combinatorial route-path-planner model takes advantage of the Biogeography- Based Optimization （BBO） algorithm to satisfy the objectives of both higher- and lower-level motion planners and guarantee the maximization of mission productivity for a single vehicle operation. The performance of the model is investigated under different scenarios, including cost constraints in time-varying operating fields. To demonstrate the reliability of the proposed model, the performance of each motion planner is separately assessed and statistical analysis is conducted to evaluate the total performance of the entire model. The simulation results indicate the stability of the proposed model and the feasibility of its application to real-time experiments.

关键词： autonomous underwater vehicles underwater missions route planning biogeography-based optimization computational intelligence

Charged Higgs Pair Production in a General Two Higgs Doublet model at e^+e^- and μ^+μ^- Linear Colliders

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Communications in Theoretical Physics 2014年第1期61卷 69-74页

作者： m.Hashemi Physics Department and Biruni Observatory College of SciencesShiraz University

In this paper, charged Higgs pair production through l^＋l^- → H^＋ H^-, where l = e or μ, is studied within the framework of a general Two Higgs Doublet model （2HDm）. The analysis is relevant to a future e^＋e^- or μ^＋ μ^- collider operating at center of mass energy of √s = 500 GeV. Two different scenarios of small and large a values are studied. Here a is the parameter, which diagonmizes the neutral CP-even Higgs boson mass matrix. Within the minimal supersymmetric standard model （mssm）, cross section of this process is almost the same at e＋ e- and #＋#- colliders. It is shown that at e^＋e^- eolliders within a general 2HDm, cross section is not sensitive to the mass of neutral Higgs bosons, however, it can acquire large values up to several picobarn at μ^＋μ^- colliders with the presence of heavy neutral Higgs bosons. A scan over Higgs boson mass parameter space is performed to analyze the effect of large masses of neutral Higgs bosons involved in the s-channel propagator and thus in the total cross section of this process.

关键词： 2HDm Higgs bosons linear colliders

Transesterification of sunflower oil in microchannels with circular obstructions

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Chinese Journal of Chemical Engineering 2018年第4期26卷 852-863页

作者： Harrson s.santana Joao L.silva Jr Deborah s.Tortola Osvaldir P.Taranto school of Chemical Engineering University of Campinas13083-852 CampinasSPBrazil Federal Institute of Education Science and Technology of South of Minas Gerais-IFSULDEMINAS37560-260 Poaso AlegreMGBrazil

The present paper studied numerical and experimentally the transesterification reaction between sunflower oil and ethanol with NaO H catalyst in microchannels with circular obstructions. The micromixer design influence on fluid mixing and oil conversion was investigated for a range of operating conditions: Reynolds number(Re = 0.1–100),Temperature(25–75 °C), ethanol/oil molar ratio(6-12), and catalyst concentration(0.75 wt%–1.25 wt%), using three microchannel configurations(Length = 35 mm; Width = 1500 μm; Height = 200 μm): T-shape – channel without obstructions; mCO – channel with 3 obstructions ensemble – equally disposed over longitudinal length;mWO – channel with 7 obstructions ensemble. The mCO micromixer was based on literature work, and the mWO is a totally new micromixer design. Experimental tests were conducted in similar conditions in microreactors using these micromixers(Length = 411 mm) made of polydimethylsiloxane. The mCO configuration presented the highest performance(mixing index of 0.80 at Re = 100), oil conversion of 81.13% at 75 °C, molar ratio of 9 and catalyst concentration of 1%. Experimental results showed high conversions for mCO and mWO configurations(99.99%) at 50 °C, molar ratio of 9 and catalyst concentration of 1%, with a residence time of 12 s.

关键词： Biodiesel sunflower oil-ethanol Transesterification reaction Circular obstructions microreactor Numerical simulation

Dissociation behavior of “dry water” C_3H_8 hydrate below ice point:Effect of phase state of unreacted residual water on a mechanism of gas hydrates dissociation

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Journal of Energy Chemistry 2015年第3期24卷 309-314页

作者： Andrey O Drachuk Vladimir P melnikov Nadezhda s molokitina Anatoliy N Nesterov Lev s Podenko Aleksey m Reshetnikov Andrey Yu manakov Institute of Earth Cryosphere SB RAS625026Malygin str.86TyumenRussian Federation Tyumen state Oil and Gas University 625000Volodarsky str.38TyumenRussian Federation Nikolaev Institute of Inorganic Chemistry SB RAS630090Lavrentiev av.3NovosibirskRussian Federation

The results on a dissociation behavior of propane hydrates prepared from ＂dry water＂ and contained unreacted residual water in the form of ice inclusions or supercooled liquid water（water solution of gas） were presented for temperatures below 273 *** temperature ramping or pressure release method was used for the dissociation of propane hydrate *** was found that the mechanism of gas hydrate dissociation at temperatures below 273 K depended on the phase state of unreacted water in the hydrate *** hydrates dissociated into ice and gas if the ice inclusions were in the hydrate *** samples of propane hydrates with inclusions of unreacted supercooled water only（without ice inclusions） dissociated into supercooled water and gas below the pressure of the supercooled water-hydrate-gas metastable equilibrium.

关键词： gas hydrates dry water supercooled liquid water ice hydrate dissociation