A Study of the Heat Transfer Characteristics of an FC-72(C6F14) Two-Phase Closed Thermosyphon with Helical Grooves on the Inner Surface

This study is a fundamental work performed to obtain basic information about designing two-phase closed thermosyphons with a working fluid of FC-72 (C₆F₁₄). FC-72 is a kind of alternative refrigerant designed to be chemically safe and more environmentally friendly than any other conventional CFC refrigerants.

To obtain experimental data on operational performances of a FC-72 two-phase closed thermosyphon, an experimental model was designed and manufactured with a micro fin groove copper tube with an outside diameter of 22.2 mm for its container, on which a series of operational performance tests were conducted. Its maximum capacity of heat transport rate was designed to be about 300–400 W. The focus was given to investigate the effects of such parameters as micro fin grooves and fill charge ratios on operational performances of the FC-72 two-phase closed thermosyphon. The experimental data on phase change heat transfer coefficients and heat transport limitations were compared with some corresponding correlations, and a couple of measures that would help to predict operational performances were suggested with some physical explanations.     

Synthesis of boron nitride nanotubes using thermal chemical vapor deposition of ball milled boron powder

Thermal chemical vapor deposition (TCVD) produces relatively pure boron nitride nanotubes (BNNTs), while it may not be enough for production. A ball milling–annealing process is beneficial in quantity; however, the generation of the impurity is most concerned. In this regard, we explored the dual syntheses of BNNTs based on the chemical reactions of solid and gaseous boron with nitrogen, respectively. Synthesis mechanisms for both were also analyzed by presenting the stepwise reaction routes. With these understandings, the production of BNNTs could be increased, while the impurities are reduced when compared with the individual one, once the experimental conditions are optimized.     

CLASSIFICATION OF ON-LINE POULTRY CARCASSES WITH BACKPROPAGATION NEURAL NETWORKS1

A transportable system equipped with an overhead shackle conveying line and a visible/near-infrared (Vis/NIR) spectrophotometer system was assembled and used at a poultry slaughter plant. The reflectance spectra of each poultry carcass hung on the moving shackle was measured with a stationary fiber optic probe, which was set 2 to 5 cm away from the carcass, depending on the size. Reflectance spectra of wholesome and unwholesome poultry carcasses on the moving shackle, set at 60 or 90 birds/min, were measured, either under room light or in a dark environment. The scanning time for each carcass was 0.32 s. Most of the unwholesome poultry carcasses for this study were septicemic and air-sacculitic. The average accuracy in classifying wholesome and unwholesome carcasses was above 94%. All the misclassified carcasses were air-sacculitic. With a shackle speed of 90 birds/min, the highest average accuracy was obtained when the reflectance was measured in the dark (97.5%). The results showed that the accuracy of classification could be improved with the maintenance of a consistent lighting environment. All results indicated the Vis/NIR spectrophotometer system would be a highly accurate, robust tool for on-line, real-time classification of wholesome and unwholesome carcasses.     

亚临界和超临界状态下甲苯-多环芳香烃体系的气液相平衡

The phase behaviors of toluene/polycyclic aromatic hydrocarbon mixture systems were investigated with a continuous-flow type apparatus at 573.2,598.2.623.2 and 648.2K,while the pressure changed from 1 tp 5 MPa,The pseudo-binary phase behaviors were predicted with the Peng-Robinson equation of state with interaction parameters between toluene and pseudo-components considered.The phase diagrams of the system have been classified following the category of phase boundary diagram models.The extraction selectivity and efficiency of toluene as a solvent was discussed by comparing with that of hexane .The prediction model for selectivity was also suggested.     

Surimi-Starch Interactions Based on Mixture Design and Regression Models

Interaction effects of starch mixtures within surimi gels were investigated by modified distance-based design and analyzed by linear and nonlinear backward regression models. Nonlinear regression model showed highly significant interaction terms of starch-surimi, starch-water, and starchstarch. The response trace plot revealed that shear stress and shear strain were quite sensitive to changes in amounts of starch components. Optimum solution with combinations of various starches, surimi, and water was provided using linear and nonlinear programming.     

Effect of preparation conditions on the formation of primary ZnO particles in filter expansion aerosol generator

Abstracts are not published in this journal