冻融循环后再生粗骨料混凝土梁受弯性能试验研究

为了研究冻融循环对再生粗骨料混凝土梁受弯性能的影响,首先通过冻融循环试验研究不同冻融循环次数对再生粗骨料混凝土质量损失率、立方体抗压强度和相对动态弹性模量的影响;然后对经历不同冻融循环次数（0、25、50、75）的再生粗骨料混凝土梁进行受弯性能试验,研究了试件的破坏形态、开裂荷载和极限荷载、混凝土和钢筋应变、跨中挠度等。结果表明：冻融循环次数由0增加到25次时,再生混凝土的质量呈增加趋势,冻融循环超过25次后,再生混凝土的质量呈不断减小的趋势;抗压强度和相对动态弹性模量随着冻融循环次数的增加而减小;再生混凝土梁的开裂荷载和极限荷载随冻融循环次数的增加而减小;再生混凝土梁的极限挠度随冻融循环次数的增加呈现出不断减小的趋势。     

Parametric Effects on the Substrate Temperature Profile in Oxy-Acetylene Flames

In the oxy-acetylene combustion method, the quality and morphology of the diamond film depends on a variety of factors, including the substrate surface temperature, gas flow rates and their ratio, and substrate position. Due to the nature of the oxy-acetylene flame, surface temperature of the substrate varies in the radial direction. The substrate temperature profile, in turn, is influenced by the coolant flow rate, nozzle size, substrate position on the heat sink, substrate position in the combustion flame, and the total flow rate of mixed gas (acetylene and oxygen). In this article, temperature measurements using fine-gauge thermocouples were made to characterize the influence of these parameters on the substrate temperature profile.     

Mixed Convection in a Ventilated Enclosure by Considering Both Geometrical Parameters and Thermo-Physical Properties of Water/Cu Nanofluid

In this study,mixed convection heat transfer and fluid flow is numerically investigated in an open system enclosure containing a heated obstacle.Effects of the ...     

A HEAT TRANSFER CORRELATION FOR VISCOELASTIC TURBULENT PIPE FLOWS

A modified version of Kale's heat transfer correlation for viscoelastic turbulent pipe flows in terms of drag reduction ratio and Weissenberg number is presented. The proposed correlation is validated with experimental data of Kwack and this study for Separan AP-273 and Polyox WSR-301 with concentrations ranging from 10 to 1000 ppm in thermally fully developed flow in pipes with diameters of 1·11 and 1·88 cm I.D. under constant wall heat flux. The agreement between the experimental data and the predictions is within a maximum deviation of 30%.