Comparisons to establish a force-balanced piston gauge and a spinning rotor gauge as the new measurement standards of MIKES

Centre for Metrology and Accreditation (MIKES) has worked towards expanding its calibration capabilities in the absolute pressure range downwards from 0.2 Pa and lowering measurement uncertainties in the range <10 kPa using a force-balanced piston gauge (FPG) and a spinning rotor gauge (SRG).MIKES was the first national pressure laboratory to purchase a novel type of piston manometer, FPG, developed by DH Instruments Inc., USA. The effective area of the FPG was at first determined at MIKES by a comparison with a conventional pressure balance. The result was confirmed in comparisons in the same pressure range with two other laboratories, Swedish National Testing and Research Institute (SP), Sweden and Institute for Metrology and Technology—Van Swinden Laboratorium (NMi-VSL), Netherlands. Next a direct comparison with the mercury column manometer of Physikalisch-Technische Bundesanstalt (PTB), Germany in the absolute pressure range from 1 to 15 kPa was carried out. Use of the FPG for calibration of capacitance diaphragm gauges (CDGs) is also presented.MIKES now uses two SRGs as reference standards, manufactured by MKS Instruments, Inc., USA. A comparison of SRGs in the range from 0.1 to 5 Pa between MIKES, SP and Vaisala Oyj accredited laboratory was performed in 2001-2002.     

Recent Progress of Textile‐Based Wearable Electronics: A Comprehensive Review of Materials,Devices, and Applications

Wearable electronics are emerging as a platform for next‐generation, human‐friendly, electronic devices. A new class of devices with various functionality and amenability for the human body is essential. These new conceptual devices are likely to be a set of various functional devices such as displays, sensors, batteries, etc., which have quite different working conditions, on or in the human body. In these aspects, electronic textiles seem to be a highly suitable possibility, due to the unique characteristics of textiles such as being light weight and flexible and their inherent warmth and the property to conform. Therefore, e‐textiles have evolved into fiber‐based electronic apparel or body attachable types in order to foster significant industrialization of the key components with adaptable formats. Although the advances are noteworthy, their electrical performance and device features are still unsatisfactory for consumer level e‐textile systems. To solve these issues, innovative structural and material designs, and novel processing technologies have been introduced into e‐textile systems. Recently reported and significantly developed functional materials and devices are summarized, including their enhanced optoelectrical and mechanical properties. Furthermore, the remaining challenges are discussed, and effective strategies to facilitate the full realization of e‐textile systems are suggested.     

Rapid synthesis of nanostructured porous silicon carbide from biogenic silica

Nanostructured silicon carbide (SiC) is an exceptional material with numerous applications, for example, in catalysis, biomedicine, high-performance composites, and sensing. In this study, a fast and scalable method of producing nanostructured SiC from plant materials by magnesiothermic reduction via self-propagating high-temperature synthesis (SHS) route was developed. The produced biogenic material possessed a high surface area above 200 m²/g with a SiC crystallite size below 10 nm, which has not been done previously by SHS. This method enables affordable synthesis of the material plant-based precursors in a reaction that only takes a few seconds, thereby paving a way for nanostructured SiC production in high volumes using renewable resources. The material was also functionalized with carboxylic acid and bisphosphonate moieties, and its use as metal adsorbent in applications such as wastewater remediation was demonstrated.     

Leg extension power and walking speed in very old people living independently

BACKGROUND: Leg extension power can be determined as the product of the force and velocity of movement. Its association with maximal walking speed was studied in 131 80- and 85-year-old men and women. METHODS: Leg extension power was measured with the help of a sledge ergometer in a sitting position using a facilitated "jump test." The participant was attached by belts to a sliding chair on rails inclined at 12.6 degrees to the floor. The feet were placed on the force plate attached perpendicularly to the rails, and the knee angle was 90 degrees at the starting position. The participant was advised to extend his or her legs powerfully. The highest value of five to eight attempts was accepted as the result. The results were adjusted for body mass and expressed as watts.kilogram-1. Maximal walking speed was measured in the laboratory corridor over a distance of 10 m. RESULTS: Men and 80-year-old subjects exhibited greater leg extension power and were faster walkers than women and 85-year-old persons. Leg extension power correlated positively with maximal walking speed in all groups: the correlation coefficients were .412 in the 80-year-old men (n = 41, p = .007), .619 in the 80-year-old women (n = 56, p < .001), .939 in the 85-year-old men (n = 8, p = .001), and.685 in the 85-year-old women (n = 23, p < .001). The regression lines for leg extension power and walking speed were coincident, indicating that the power requirements to attain a given walking speed were similar for both sexes. The minimum power threshold for those with a maximal walking speed of 1.30-1.49 m.s-1 was on the order of 4 W.kg-1; a maximal walking speed of 1.50-1.99 m.s-1 required 7 W.kg-1; and for a speed over 2.00 m.s-1 the power threshold was 9.5 W.kg-1. CONCLUSIONS: Their lower average leg extension power may be one of the factors explaining the greater prevalence of mobility problems among women than men.     

Eye contact and video-mediated communication: A review

A relatively new form of human communication, video-conferencing has become more popular as video technology improves and with increasing demands for real-time communication across greater distances. The full effects of video-conferencing on human communication are still being explored. Video-conferencing is presumed to be a somewhat richer form of communication than email and telephone, but not quite as informative as face-to-face communication. This review explores research into the influence of eye contact on communication and how video-conferencing mediates both verbal and non-verbal interactions. Facilitation of eye contact is a challenge that must be addressed so that video-conferencing can approach the rich interactions of face-to-face communication.     

Effect of Natural Fiber Network on Permeability and Tensile Strength of Composites through Vacuum Infusion Process

This investigation is primarily focused to study the effect of fiber network on the permeability in vacuum infusion molding process. The unsaturated permeability of several natural fiber mats with different networks is measured. The experimental permeabilities are fitted by the Kozeny model and contact angle model. The outcome highlighted that the contact angle model shows more precise results as compared to kozeny model. The obtained permeability for the random fiber mats shows higher values than directional fiber mat. Furthermore, the maximum increase in tensile strength is observed in the unidirectional composites and the flow along the fiber direction.     

光网络的管理

光网络的发展促进了对光网络管理的研究。介绍了光网的发展,并重点讨论了光网的管理。探讨了光网的配置管理、性能管理、故障管理及安全管理。其中对于线型、环形光网的保护恢复机理做了详细的分析和研究。     

Numerical and Experimental Validation of Natural Fiber Orientation in Viscous Fluid of Injection Cavity

In an injection moulded product, the orientation of short fiber in polymer composite influences the strength of the product. A method was developed to predict orientation of natural fiber in thermoset composite. The purpose of this investigation is to predict the orientation of natural fiber in a viscous fluid and to study fiber flow in mould cavity. An experimental set up was developed on injecting viscous fluid with short natural inside the transparent mould cavity and visualize the orientation of short natural fiber and flow front during filling period of cavity. The proposed model for natural fiber orientation was derived by coupling the tangential orientation of natural fiber in flow front and constant curling factor in angular velocity of fluid element. The orientation angle was predicted through proposed model at specified position and was validated with experimental method through digitized image analysis technique.     

预制装配式基坑支护体系

本文针对以往高层建筑地下室深基坑围护与支撑体系在施工中常因支撑的设置和拆除花费巨大的代价和占用宝贵的工期等问题,提出“静压式预制桩+预制装配式支撑”的支护体系构想的设计,优先选用T形、工形予制桩,支撑为装配式连拱形钢管混凝土结构。文中对每个构件及节点设计已确定了明确的原则,达到了可以实施的程度。