稀土元素Ce对K-52合金高温拉伸性能的影响

利用Gp-Ts20 000M热模拟机对添加稀土元素Ce的K-52奥氏体耐热钢在常温(25℃)、300℃、500℃和700℃下,以2 mm/min的拉伸速度进行拉伸试验。通过分析试样的宏观变形、力学性能变化曲线和断口形貌等,研究了稀土元素Ce对试验钢高温拉伸性能的影响,并分析其断裂机理。结果表明,随着拉伸温度的提高,金属有向塑性变形转变的趋势;试验钢中添加稀土元素Ce后,提高了合金的高温力学性能,其拉伸断口中的韧窝数量增多。与未添加稀土元素的合金相比,添加稀土元素Ce的K-52合金其屈服强度、抗拉强度和伸长率分别提高了5.37%、11.69%和22.82%。     

Whey Protein Coating Effect on The Oxygen Uptake of Dry Roasted Peanuts

A procedure was developed to coat peanuts with aqueous whey protein isolate (WPI) solutions based on increasing coating-solution viscosity. Oxygen uptake of WPI-coated nuts and uncoated nuts were compared. WPI coatings delayed oxygen uptake of dry roasted peanuts at intermediate (53%) and low (21%) storage relative humidity. They had similar results at 29°C and 37°C. The effects of coating thickness and storage relative humidity indicate that the mechanism of protection of the coatings was through their oxygen barrier properties.     

SELECTION OF A CATION EXCHANGE RESIN TO PRODUCE LACTIC ACID SOLUTIONS FROM WHEY FERMENTATION BROTHS

ABSTRACT

Lactic acid can be made by fermentation from inexpensive cheese whey. The acid is at present fairly costly, however, partly because of the costs of recovery and purification of the acid from the fementation broths. The present study has been undertaken to investigate a process that might reduce these costs. A number of commercial resins have been evaluated as ion exchangers for the production of lactic acid solutions. Amberlite IR-120, a gel strong cationic ion exchanger, was found to be the best resin. The loaded resin was regenerated efficiently. The results suggest that such a process is both technically and economically feasible.     

Technical note Seafloor characterization through side scan sonar image processing

This paper presents the most suitable image processing techniques being used at present for recognising features either lying on the seafloor or floating in the water column. The preprocessing methodology is already incorporated in the sonar system, and as we cannot access the raw data, it is not included in this paper. The studied images correspond to the Cabrera Archipelago, in the Mediterranean Sea.     

LIQUID-LIQUID EQUILIBRIUM OF THE SYSTEM WATER-PHOSPHORIC ACID-DI-N-PROPYL ETHER AT 25 AND 40°C. INFLUENCE OF THE ISOMER PROPYL-ISOPROPYL ETHER ON THE APPEARANCE OF THREE LIQUID PHASES AT EQUILIBRIUM.

Solubility and liquid-liquid phase equilibrium data have been determined for the ternary systems Water-Phosphoric Acid-Di-n-propyl Ether as supplied by Merck (with about 6.4% of the isomer propyl-isopropyl ether), and Water-Phosphoric Acid-Di-n-propyl Ether (rectified up to less than 1% of propyl-isopropyl ether), at 25 and 40^°C The temperatures at which three liquid phases at equilibrium appeared were 28.0-28.2^°C and 49.0-50.0^°C, respectively. The presence of the isomer propyl-isopropyl ether causes these systems to split into three liquid phases at equilibrium     

Analysis of electric quadrupole radiation in the time domain: application to large-current radiators

In this paper, the fields created by a hertzian electric quadrupole fed by a non-sinusoidal signal are analysed in the time domain. The results are compared with those obtained for an electric dipole and are applied to the study of the field created by the practical antenna, the large-current radiator.     

ANALYSIS OF LAMINATE METAL MATRIX COMPOSITES

This article describes an integrated micro/ macro mechanical study of the thermo-elastic-uiscoplastic behavior of unidirectional metal matrix composites. The microme-chanical analysis of the elastic moduli are based on the representative unit cell approach with comparisons also drawn with the composite cylinder assemblage model. These “ homogenization ” results are later incorporated into the vanishing fiber diameter model develop the macroscopic stress-strain relations. The finite element method is employed for the analysis in conjunction with the Bodner and Partom thermoviscoplas-tic constitutive model for the associated macroscopic analysis and a “ smeared” element approach. Comparisons are made against experimental and analytical results available in the literature whenever feasible.     

IMPROVING FATTY EXTRUDATE STRUCTURE WITH AMYLASE AND PROTEASE

The extrusion of fatty flour at temperatures less than 100C on the one hand favors less leakage of oil from plant and products, but on the other hand reduces the degree of expansion unless suitable technological coadjuvants are used. Enzymes are generally used in the preparation of bread to mellow gluten and to soften texture. At the moment, there is little information about the use of enzymes to improve the texture of extruded products. The effect of two commercially available enzymes (GRINDAMYL Amylase 1000 and GRINDAMYL Protease 41) on the texture of products obtained from wheat and almond flours extruded at low temperature (54C) was studied. GRINDAMYL Protease 41 was found to affect the rheological characteristics of dough by rapid decreasing the consistency during farinographic analyses and by improving the structure of extrudates with a high lipid content (reduced breaking strength, high% porosity and high water solubility index).     

Synthesis and chemical etching of Te/C nanocables

In this paper, Te/C nanocables were fabricated by a hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The products were characterized in detail by multiform techniques: transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis and Fourier transform infrared (FTIR) spectroscopy. The results showed that the products were nanocables with lengths of several microns, core about 20 nm in diameter, and a surrounding sheath of about 60–80 nm in thickness. Te/C nanocables were tailored freely by chemical etching. Carbonaceous nanotubes and Te/C nanocables with fragmentary Te core were obtained by adjusting time of chemical etching.