Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100–400W/cm² and three frequencies ranging from 25–68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm2 and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress.     

Cryogenic Yb3+-Doped Solid-State Lasers

Cryogenically cooled solid-state lasers promise a revolution in power scalability while maintaining a good beam quality because of significant improvements in efficiency and thermo-optic properties. This is particularly true for Yb lasers because of their relatively low quantum defect and relatively broadband absorption even at cryogenic temperatures. Thermo-optic properties of host materials, including thermal conductivity, thermal expansion, and refractive index at low temperature, are reviewed and data presented for YAG (ceramic and single crystal), GGG, GdVO₄, and Y₂O₃. Spectroscopic properties of Yb:YAG and Yb:LiYF₄ (YLF) including absorption cross sections, emission cross sections, and fluorescence lifetimes at cryogenic temperatures are characterized. Recent experiments have pushed the power from an end-pumped cryogenically cooled Yb:YAG laser to 455-W continuous-wave output power from 640-W incident pump power at an of M² 1.4.     

Frictional behavior of piston rings of small utility two-stroke engine under secondary motion of piston

The secondary motion of the piston head of a motorized engine is captured using two laser displacement sensors to obtain the piston motion and tilt angle. The controlled parameters of the measurement are engine speed, quantity of oil and oil-fuel mixture and its ratio. The reduction in friction force is more significant at dead center at high speed as the quantity of oil supplied increases. Changes in tilt direction of piston head occur at the inlet port. The relationship between the friction force and piston tilt angle showed weak correlation at low speed and increases with the engine speed.     

A study on high ratio cup drawing by Maslennikov’s process

Deep drawing of sheet metals using Maslennikov’s technique has been analyzed by analytical and finite element simulation approaches. A new friction model based on local contact conditions has been used in the finite element (FE) simulations of the process. Compared to traditional Coulomb friction model, the results of FE simulations with the new friction model show good correlation with analytical calculations. The effects of key process parameters such as rubber ring thickness, ring inner diameter, die hole diameter, and die profile radius on the results have been investigated. The results showed that very deep cups without thinning in the side wall portion can be achieved with this process. Based on the results of FE analysis, it was found that the maximum drawing ratio can be achieved by adopting a combination of process parameters which correspond to points nearest to the fracture limit.     

Analysis of deep drawing of sheet metal using the Marform process

This paper deals with the deep drawing of metal cups using the Marform process. Using this technique, higher limiting drawing ratios can be obtained compared with the conventional deep drawing process. The analytical model of the process is presented initially, followed by the finite element simulations using ABAQUS software. A new friction model based on local contact conditions is presented and used in the finite element (FE) simulations of the process. Compared with traditional Coulomb friction model, the results of the FE simulations with the new friction model showed good correlation with experimental results. The results showed that the maximum thinning occurs at the punch profile portion, and by increasing the forming pressure, thinning of the sheet metal propagates from the punch profile portion to the side wall. At low forming pressures, wrinkles appear in the flange, whilst at higher pressures, fracture is the main defect of the Marform process.     

双金属复合剪刃

研究了用电焊堆焊法制造双金属复合剪刃的工艺技术，以废旧３Ｃｒ２Ｗ８Ｖ钢整体剪刃为基体，在刃口处堆焊耐热合金，使其使用寿命比３Ｃｒ２Ｗ８Ｖ钢整体剪刃提高１０倍。     

Quantifying the surface roughness effect in microindentation using a proportional specimen resistance model

The influence of the surface roughness on the indentation size effect in microindentation was examined using the proportional specimen resistance model. Stainless steel, aluminium, and copper surfaces were polished to different levels of roughness and subjected to microindentation. The results showed that the indentation size effect increases with increasing surface roughness, according to the proportional specimen resistance model. A normalized hardness equation H/H ₀ = (c ₀ + c ₁ R _a)/(a ₂ d) + 1 was established, and the value of c ₁ can be used to quantify the effect of surface roughness on the severity of the indentation size effect; this value was found to be highest for stainless steel, followed by copper and aluminium.     

Analysis of Surface Parameters and Vibration of Roller Bearing

The surface of the inner race of a detachable roller bearing is monitored periodically to determine the deterioration pattern under normal conditions together with the vibration level. The surface of the inner race is scanned using an infinite focus microscope to evaluate surface properties utilizing the 2D and 3D parameters. Both parameters successfully assess the surface degradation and wear of the bearing surface. Using the Dowson-Higginson equation on elastohydrodynamic lubrication, the theoretical lubrication film was calculated and the lubrication regimes identified. A high vibration level can be associated with surface roughness properties and relative lubrication regime. This work highlights the relationship between the bearing vibration level and the bearing inner race surface parameters. The two surface parameters with the highest Pearson correlation coefficient with the vibration level are the areal surface roughness S_a (0.997) and the average roughness R_a (0.936).     

Numerical and experimental investigations on effect of fan height on the performance of piezoelectric fan in microelectronic cooling

A piezoelectric fan is an attractive device to remove heat from microelectronic systems due to its low power consumption, minimal noise and compactness. In the present study, a piezoelectric fan is investigated to analyze the cooling capability for possible use in electronic devices. Both numerical and experimental analyses are carried out on the piezoelectric fan which was oriented horizontally. The FLUENT 6.3 software is used in the 2D simulation to predict the heat transfer coefficient and the flow fields using a dynamic mesh option to observe the fan swinging phenomena. Two heat sources in in-line arrangement are used in the experiment. The flow measurements are carried out at different piezoelectric fan heights by using a particle image velocimetry (PIV) system. The result shows that the piezofan height of h_p/l_p = 0.23 can reduce the temperature of the heat source surface as much as 68.9 °C. The numerical and experimental values of heat transfer coefficients are plotted and found in good agreement.     

Report of panel 2: Post-TFTR initiatives

Conclusion The Panel finds that the steady-state/advanced-to-kamak mission is a critical element in the U.S. fusion strategy as established by FPAC. An attractive SS/AT device can be constructed for about the $400M FY'92 guideline proposed by the SEAB-TF. The design and construction of such a facility should proceed on a schedule to enter operation in 1990–00. Adequate funding for peak construction years should become available following the D-T operation of TFTR. In all its phases, the new device should be managed as a national facility.This report was prepared by a panel established by, and reporting to, the Fusion Energy Advisory Committee (FEAC). The report of this panel should not be construed as representing the views, official advice or recommendations of FEAC.This document uses SS/AT to identify the mission and TPX to identify a generic facility addressing the mission.