Investigation of composite ☐ beam dynamics using a higher-order theory

A higher-order composite ☐ beam theory is developed to model beams with arbitrary wall thicknesses. The theory, which is based on a refined displacement field, approximates the three-dimensional elasticity solution so that the beam cross-sectional properties are not reduced to one-dimensional beam parameters. Both inplane and out-of-plane warping are included automatically in the formulation. The model can accurately capture the tranverse shear stresses through the thickness of each wall while satisfying stress-free boundary conditions on the inner and outer surfaces of the beam. Numerical results are presented for beams with varying wall thicknesses and aspect ratios. The static results are correlated with available experimental data and show excellent agreement. Dynamic results presented show the importance of including inplane and out-of-plane warping deformations in the formulation.     

智能数字万用表的设计

本系统采用TI公司的单片机MSP430F2274作为系统的控制核心,由A/D数据采集、功能转换、量程自动转换以及键盘显示等模块组成。被测信号经过功能转换电路,转换成与其成比例关系的电压,再经12位AD574转换送单片机进行数据处理,结合继电器完成量程的自动转换,从而通过由MC14433组成的数字电压表头实时反映测试参数,同时本系统还具有相对误差测量、自动休眠等功能。通过实验测试,该系统满足设计要求,具有量程自动转换,具有精度高、工作稳定、交互界面友好等特色。     

Effect of ohmic contacts on buffer leakage of GaN transistors

The effect of ohmic contacts on the buffer leakage of GaN transistors is presented. The buffer leakage for AlGaN/GaN high-electron mobility transistors and GaN MESFETs grown on the same underlying buffer was observed to be different. Controlled experiments show that the increased buffer leakage is due to the nature of the alloyed ohmic contacts and can be minimized if they are screened by the Si doping or by the two-dimensional electron gas.     

红外摄像机可以检测集成电路芯片

根据莫尔(Moore)定律,半导体集成电路芯片上的晶体管的数量每隔18个月将会增加一倍,这对我们在日常生活中使用电子学线路的大多数人来说,无疑是一个很好的消息.但是,对美国高级微型器件公司的Brennan Davis实验室来说,它意味着"干草堆"变得越来越大,而"针子"变得越来越小(意思是在芯片上寻找故障或缺陷更难,犹如大海捞针-译者注).Davis实验室检测封装的晶体管芯片,以验证那些不合格、有缺陷的逻辑电路,或验证那些接触不良的接点.检测的工具之一是采用由美国Sensors传感器无限公司研制的、基于InGaAs的红外摄像机(红外相机).     

Evaluation of the effects of sodium chloride,potassium sorbate,nisin and lysozyme on the probability of growth of Clostridium sporogenes

The aim of this study was to evaluate the combined effect of salt (sodium chloride, 0–8% w/v), sorbate (potassium sorbate, 0–4.5% w/v), nisin (0–500 ppm) and lysozyme (0–500 ppm) on the survival of Clostridium sporogenes as a non‐toxigenic surrogate of Clostridium botulinum in terms of the probability of growth by using a central composite rotatable design. The results indicated that salt and sorbate were the most effective factors in preventing the growth of Cl. sporogenes in high‐moisture (>95%) and low‐acid conditions. The probability of growth of Cl. sporogenes in broth was reduced by combinations of salt and sorbate. Nisin and lysozyme had insignificant effects on the probability of growth of Cl. sporogenes (P > 0.05). Lysozyme individually and in combination with nisin had no inhibitory effect on Cl. sporogenes. Overall, the addition of sorbate and lysozyme may allow the salt concentration to be reduced while preventing growth.     

The role of acidity,sweetness, tannin and consumer knowledge on wine and food match perceptions

The purposes of this study were to (1) explore significant differences in perception of match for a variety of food and wine styles; (2) evaluate the impacts of wine sweetness level, wine acidity level, and wine tannin level on perception of match; and (3) investigate the impact of food and wine expertise on perceived level of match. The highest perceived wine matches for each food item were: Sauvignon Blanc and chêvre, Chardonnay and brie, Cabernet Sauvignon and spicy Italian salami, and Port and milk chocolate. Wine sweetness, acidity, and tannin levels all significantly impacted the level of match with certain food items. Food and wine expertise also significantly impacted the level of match, indicating differences between the more expert and novice participants in the role wine sweetness, acidity, and tannin had on level of match.     

(Re)conceptualising the boundaries between home and homelessness: the unheimlich

A burgeoning cross-disciplinary literature signifies a move towards diversifying understandings of the meanings of ‘home’. Homelessness is inextricably bound up in these definitions. While earlier work has considered meanings of homelessness, attempts to advance understandings of the relationship between home and homelessness have been sporadic. This article attempts to reinvigorate discussion around the home–homelessness relationship by problematizing the binaries in current understandings and poses a different way of theorizing the interplay between the two concepts. Drawing on interviews with women accessing homelessness services in the North of England, discussion interweaves women’s meanings of home and homelessness with the Freudian notion of the ‘unheimlich’. The ‘unheimlich’ captures the uncanny process of inversion whereby the familiar domestic sphere of the house turns into a frightening place; and a typical space of homelessness—the hostel—is considered home. The article seeks to contribute more adequate theoretical tools for future research to better understand and articulate the complexities of home and homelessness.     

Survival of Salmonella Enteritidis PT 30 on inoculated almond kernels in hot water treatments

Almonds are blanched by exposure to hot water or steam-injected water to remove the pellicle (skin) from the kernel. This study evaluated the survival of Salmonella Enteritidis PT 30, Salmonella Senftenberg 775W and Enterococcus faecalis on whole raw almond kernels exposed to hot water. Whole, inoculated (7 to 9 log CFU/g) Nonpareil almonds (40 g) were submerged in 25 L of water maintained at 60, 70, 80 and 88 °C. Almonds were heated for up to 12 min, drained for 2 s, and transferred to 80 mL of cold (4 °C) tryptic soy broth. Almonds in broth were stomached at high speed for 2 min, serially diluted, plated onto tryptic soy and bismuth sulfite agars (Salmonella) or bile esculin agar (Enterococcus) and incubated at 37 °C for 24 and 48 h, respectively. D values of 2.6, 1.2, 0.75 and 0.39 min were calculated for exposure of S. Enteritidis PT 30 to water at 60, 70, 80 and 88 °C, respectively; the calculated z value was 35 C°. D values determined for Salmonella Senftenberg 775W and E. faecalis at 88 °C were 0.37 and 0.36 min, respectively. Neither Salmonella serovar could be recovered by enrichment of 1-g samples after almonds inoculated at 5 log CFU/g were heated at 88 °C for 2 min. These data will be useful to validate almond industry blanching processes.     

Validation of mid-infrared spectrometry in milk for predicting body energy status in Holstein-Friesian cows

Cow energy balance is known to be associated with cow health and fertility; therefore, routine access to data on energy balance can be useful in both management and breeding decisions to improve cow performance. The objective of this study was to determine if individual cow milk mid-infrared spectra (MIR) could be useful to predict cow energy balance across contrasting production systems. Direct energy balance was calculated as the differential between energy intake and energy output in milk and maintenance (maintenance was predicted using body weight). Body energy content was calculated from (change in) body weight and body condition score. Following editing, 2,992 morning, 2,742 midday, and 2,989 evening milk MIR records from 564 lactations on 337 Scottish cows, managed in a confinement system on 1 of 2 diets, were available. An additional 844 morning and 820 evening milk spectral records from 338 lactations on 244 Irish cows offered a predominantly grazed grass diet were also available. Equations were developed to predict body energy status using the milk spectral data and milk yield as predictor variables. Several different approaches were used to test the robustness of the equations calibrated in one data set and validated in another. The analyses clearly showed that the variation in the validation data set must be represented in the calibration data set. The accuracy (i.e., square root of the coefficient of multiple determinations) of predicting, from MIR, direct energy balance, body energy content, and energy intake was 0.47 to 0.69, 0.51 to 0.56, and 0.76 to 0.80, respectively. This highlights the ability of milk MIR to predict body energy balance, energy content, and energy intake with reasonable accuracy. Very high accuracy, however, was not expected, given the likely random errors in the calculation of these energy status traits using field data.