The adaptive da/dN method: a solution to the problem of processing crack growth data

The standard fatigue data‐processing procedure, published in ASTM E647, is not adapted to the use of modern crack length measurement techniques. Because the use of this standard is usually required by journals, the raw data are often reduced to only a few data points. This way valuable information is simply thrown away and mathematical errors are unintentionally made. More importantly, the fact that no satisfactory reduction method exists, has led to destandardization of the processing procedure. Therefore, a new standard processing method is desired. In this paper a new data‐processing method, referred to as the ‘adaptive da/dN method’, is proposed and discussed. This method is suitable for both optical and modern (electrical or automated) measurement techniques as well as modern (computer‐assisted or ‐controlled) processing techniques. The adaptive da/dN method is validated both by data generated with a certain amount of scatter as well as actual experimental data. It shows a more accurate behaviour than the ASTM standards for all data types.     

Private Camera Conversation: a new method for eliciting user responses?

This paper discusses a new method called Private Camera Conversation. This method can be used to elicit user opinions on various subjects like their use of products. Initial impressions of the method are given on the basis of three small studies in which the method was employed. The method has not yet been validated and compared with existing human factors methods. This study reports the first findings of the application of the method. With Private Camera Conversation people are invited to talk about a particular topic in private to a video camera. The participants themselves decide when they want to start and when they want to stop the recording session. Initial impressions arc that the method has potential benefits for eliciting rich and useful responses even with respect to 'personal' issues. The Private Camera Conversation method seems particularly suitable for obtaining information about the social context in which products are used and about qualitative aspects of product use. The method is inviting and entertaining for participants and easy and effective to carry out. Optimal exploitation of the method has to be realized through further development. We hope this article will be a catalyst for further research.     

EFFECTS OF NEUTRON IRRADIATION ON LOW-CYCLE FATIGUE AND TENSILE PROPERTIES OF AISI TYPE 304 STAINLESS STEEL AT 298 K

Abstract— Room temperature studies have been made of the effect of neutron damage on the mechanisms concerned with the low-cycle fatigue and tensile test behaviour of stainless steel AISI Type 304. Samples were irradiated in the HFR at Petten to a fast fluence of 5·10²⁴ n m⁻² ( E > 0·1 MeV) at 333 K followed by mechanical testing at room temperature. The low temperature irradiation caused irradiation hardening: the 0·2 yield stress increased from 230 MN m⁻² for the unirradiated material to a lower yield point value of 540 MN m⁻². Irradiation had no significant effect on fatigue life. The loop type damage was removed by glide dislocations resulting in cyclic softening. Dislocation substructures were observed after fatigue testing: cell structures were more pronounced after fatigue testing to failure the higher the applied strain ranges.
The formation of fatigue cracks at the surface of the specimens was observed in a series of specimens exposed to an increasing number of fatigue cycles.     

α-Tocopherol, β-Carotene and Ascorbic Acid as Antioxidants in Stored Poultry Muscle

Broilers were fed α-tocopherol or β-carotene for 3 wk or L-ascorbic acid for 24 hr prior to slaughter. α-Tocopherol maintained the redness of unheated meat stored for 8 wk (—20°C). Values for thiobarbituric acid reactive substances in ground, stored meat showed that L-ascorbic acid produced results similar to the control while a-tocopherol produced results lower than the control. Panelists rated meat with added α-tocopherol as different from the control for smell and flavor. β-Carotene was a pro-oxidant compared to the control and other additives. Meat from broilers fed β-carotene had lower α-tocopherol content than the control. Vitamin A in livers of birds fed β-carotene was 64% higher than that of the control.     

多出口选择中的几何影响因素定量化研究

成功预测逃生者对出口的选择对于建筑师和消防评估人员都非常重要,它直接关系到设计或评估的可靠性.本研究从建筑学的视角出发,定量分析了空间设计中有关出口的6项几何特征是如何影响逃生者对其的选择的.通过将虚拟逃生实验技术与二元回归统计方法相结合,解决了该领域研究所面临的现实环境中出口几何特征组合案例有限、特征难以以抽象形式独...     

Effect of lactic acid treatment during processing on the sensory quality and lactic acid content of fresh broiler chickens

Microbial decontamination by lactic acid treatment during processing of fresh broiler chickens is an effective way to produce a safer product with good keeping quality. It remained to be assessed whether such a treatment adversely affects the organoleptic quality of the product. Lactic acid treatment results in an increased acid concentration in the skin, with no increase in lactic acid concentration in the underlying muscle tissue. Differences in sensory quality were only found in appearance of the carcasses, the controls being identified as discoloured. A preference test did not show any difference in lactic acid treated and untreated grilled legs.     

Aroma Changes in Fresh Bell Peppers (Capsicum annuum) after Hot-air Drying

The aroma of fresh and hot-air dried bell peppers (Capsicum annuum) was evaluated by sensory and instrumental methods. Hot-air drying decreased levels of the odor compounds (Z)-3-hexenal, 2-heptanone, (Z)-2-hexenal, (E)-2-hexenal, hexanol, (Z)-3-hexanol, (E)-2-hexenol, and linalool, which have green, vegetable-like, fruity, and floral notes, while intensity scores of corresponding sensory aroma attributes also decreased. The aroma of rehydrated dried samples was mainly characterized as savory, rancid/sweaty, sweet/sickly, hay-like, cacao, caramel, and nutty. Drying increased the levels of 2-methylpropanal, 2-and 3-methylbutanal, which have cacao, spicy, and rancid/sweaty odor notes; these volatiles may be correlated with the corresponding aroma attributes in the dried fruits. Principal component analysis demonstrated relationships between instrumental and sensory data for fresh samples, whereas they were more complex for dried fruits.     

Critical Evaluation of the Literature Data on Beta Alumina and Related Phases: I, Phase Equilibria and Characterization of Beta Alumina Phases

From a critical evaluation of the available data on the system Na₂O-Al₂O₂ and particularly on β-Al₂O₃ some of the discrepancies in the literature were resolved, and plausible phase diagrams for the system were constructed. The diagrams define needed equilibrium data and are useful in putting into perspective the problems that have arisen with regard to synthesis and characterization of the 3–block and 3–block forms of β-Al₂O₃.     

HPLC Determination of Caffeine and Theobromine Content of Various Natural and Red Dutched Cocoas

Eighteen randomly selected cocoa samples were analyzed in duplicate by HPLC for caffeine and theobromine. The relative standard deviation for the method was determined to be 1.55%. The mean ± S.D. of the theobromine plus caffeine content (moisture free basis) was 2.85 ± 0.08% with a 90% confidence interval of 2.72–2.98% for red Dutched cocoa. The total ± SD. for natural cocoas was 2.82 + 0.16% with a 90% confidence interval of 2.56–3.08%.