AN INVESTIGATION OF THE CREEP-FATIGUE-ENVIRONMENT INTERACTION IN A Ni-BASE SUPERALLOY

Abstract— This work was conducted to study the significant increases in fatigue crack growth rates at low frequencies commonly observed at high temperature. Creep tests and fatigue tests at 0·01, 0·1 and 1·0 Hz were conducted at 650°C in air and in helium on samples of INCONEL alloy 718 in two different heat treatments. Creep crack growth rates were 50–100 times greater in air than in helium. Fatigue tests in helium showed little sensitivity to frequency, but tests in air showed considerable increases in crack growth rates at lower frequencies. The results indicate the air environment played a predominant role in both the creep and the fatigue tests. Oxygen diffusion into grain boundaries appeared responsible for the accelerated crack growth in air. An overaging heat treatment reduced the crack growth rates.     

Lemon Juice Aroma Concentration by Reverse Osmosis

Ethanol, a major component of lemon juice, was analyzed to indicate degree of lemon juice aroma concentration. Aroma solution was concentrated from 12.2 to 23.4% ethanol at 8.3 MPa and 19°C by reverse osmosis. Ethanol rejected by the membrane decreased from the initial 87.7% to 78% at the final aroma concentration of 23.4% ethanol. Membrane rejection of neral, geranial, and terpinene-4-ol was > 96% while rejection of the alcohols, n-propanol, 2-methyl-3-buten-2-ol, and 3-methyl-2-buten-1-ol, ranged from 6.9% to 83.5%. Sensory analysis indicated no difference between initial aroma and aroma concentrated by reverse osmosis. Mass balance determined the true recovery of total volatiles was 79.7%. Loss of volatiles was attributed to adsorption in the polymeric matrix of the membrane and some loss was attributed to cleaning.     

巨龙与沙土 摩弗西斯事务所巨人集团上海联合总部的设计与建造

文章通过介绍摩弗西斯事务所第一件在中国完成的作品——上海松江巨人集团园区,简述建筑师如何在一片处在城市边缘的基地中,将园区所要求的多样功能以"层叠"的方式穿插整合,塑造建筑与景观勾连起伏的形象;另一方面通过笔者与项目建筑师的对话回顾这座建筑在中国建造现实下的实现过程,反映了"几何"在事务所建筑生成与建造控制两个过程中的连续作用。     

Effect of Chilling-Injury on Texture and Fungal Rot of Mangoes (Mangifera indica L.)

In this study we have considered the evolution of texture as determined by a puncture test and of the intensity of fungal rot in mangoes. Fruits were placed at room temperatures after 3 wk storage at 4° or 12°C under various humidity conditions. Observed differences in hardness (INSTRON) of the skin and the flesh appeared related to fruit ripening. Inducing chilling-injury on fruits initially stored at 4°C accelerated softening after fruits were transferred at 20°C. Gradual humidification of ambient atmosphere reduced this phenomenon, especially by limiting water losses, thus maintaining cell turgescence. Susceptibility to fungal rotting increased with fruit softening. Fungi proliferation seemed more rapid on chilling-injured batches. A clear relationship was evidenced between water losses and fungal development.     

A real-time adaptive line enhancer hardware implementation designed for a plasma estimation application†

A real-time adaptive line enhancer hardware system has been implemented for noise cancellation in a nuclear fusion instrumentation project. The noise cancellation circuitry, realized with a standard digital signal processor (DSP) chip, uses a direct form adaptive filter and adapts using the least-mean-squares (LMS) algorithm. The noise cancellation circuitry adapts the noise filter weights to the line noise prior to an experiment. Upon initiation of the experiment, the adaption is stopped for the duration of the experiment. Experimental data with noise cancelling may be recorded during the experiment. After the experiment, noise filter weights may be read out to be included with the experimental record for possible later evaluation. The use of these hardware systems could significantly reduce the presently enormous requirements for off-line signal processing to extract plasma information. In this paper, real-time capabilities of the line enhancer circuitry for noise cancellation are demonstrated for simple examples and for the nonstationary fusion experiment data. Performance trade-offs in terms of sampling rate and filter complexity are given.     

Lattice Constants and Dielectric Properties of Barium Titanate—Barium Stannate—Strontium Titanate Bodies

Lattice constants and temperatures corresponding to maximum dielectric permittivity were investigated for compositions in the barium titanate-rich portion of the system barium titanate–barium stannate–strontium titanate. Substitution of tin for titanium increases the lattice constant at room temperature, and substitution of strontium for barium decreases this parameter. Both types of substitution decrease the Curie temperature; tin is about twice as effective as strontium in this regard. Properties of bodies containing both tin and strontium are intermediate between those of bodies containing either alone.     

Time and Temperature Effect on Stability of Moroccan Processed Orange Juice during Storage

The loss of quality of processed pasteurized orange juice stored at 4°C, 22.5°C, 35°C, and 45°C for up to 14 wks was evaluated. The results showed that parameters such as pH, total solids, titratable acidity, formal index, and total sugars did not significantly change during storage at all temperatures. However, a major change was observed for ascorbic acid content, reducing sugars and furfural production, except for storage temperature at 4°C. Ascorbic acid degradation, sucrose hydrolysis, and furfural build-up followed pseudo-zero order reaction kinetics. The minimal change of formol number and total sugars suggested that nonenzymatic browning was mainly due to ascorbic acid degradation. Fufurfal formation during storage was found to be much higher than that reported in the literature.     

ZONING AND LAND USE: A TALE OF INCOMPATIBILITY AND ENVIRONMENTAL INJUSTICE IN EARLY PHOENIX

Little attention has been paid to the role of early land use institutions in development patterns, the creation of disamenity zones of environmental injustice, and the promotion of space‐consuming suburban development. This study uses historic Sanborn Fire Insurance maps and spatial analytic techniques to expose zoning's tendency to spread disamenities and disperse incompatible land uses in early Phoenix. While on paper Euclidean zoning's stratification of land uses in Phoenix promotes progressive ideals for reduction of blight and improvement of city health, analysis at a finer scale using Sanborn maps reveals that zoning decisions in Phoenix tended to promote the expansion of fragmented land uses, especially disamenity zones that targeted poor minority neighborhoods. Zoning encouraged the expansion of industry while attracting residents to newly developed suburbs with guaranteed protection from blight.