Vapor Phase Fabrication of Hydrophilic and Hydrophobic Asymmetric Polymer Membranes

The fabrication of asymmetric polymer membranes via vapor phase deposition is demonstrated. In this solventless process, the dense layer is deposited first and then the porous layer is subsequently deposited onto the dense layer. A variety of functional polymer membranes can be produced by varying the precursor molecules. The functionality of the dense and porous layers can be independently tailored to be either hydrophobic or hydrophilic, resulting in membranes that are fully hydrophilic, fully hydrophobic, or asymmetric in both structure and chemical functionality. The thickness of both the porous and dense layers can be separately tuned by controlling the deposition time.

     

Neck,shoulder and low back pain in secondary schoolchildren in relation to schoolbag carriage: Should the recommended weight limits be gender-specific?

The occurrence of neck, shoulder and low back complaints in relation to schoolbag carriage and other potential risk factors were investigated in a cross-sectional study of 586 Iranian schoolchildren aged 12–14 years. The average load carried by schoolchildren was 2.8 kg. Neck, shoulder and low back complaints during the preceding month were reported by 35.3%, 26.1% and 33% of the students, respectively. Gender was an independent factor predicting musculoskeletal symptoms in schoolchildren. Girls were more likely than boys to suffer from neck, shoulder and low back complaints, although there was no significant difference between genders in terms of schoolbag carriage variables. The findings suggest that the recommended weight limit for schoolbag carriage may need to differ between boys and girls. The associations between schoolbag variables and reported symptoms are also discussed. The results provide evidence that the current weight limit should consider a broader combination of factors that influence the use of schoolbags.     

Fluctuating surface shear stresses on bluff bodies

A pulsed wall gauge has been used to obtain measurements of the mean and fluctuating skin friction on the top surface of bluff bodies mounted in thick turbulent boundary layers. The mean flow results presented in our earlier paper [2] are complemented here by further mean surface shear stress data and by fluctuating data, which include some measurements of the probability density function of the instantaneous surface shear stress. By suitable combinations of body geometry and upstream flow properties three different “types” of flow, characterised by very different mean flow behaviour in the vicinity of the body, have been investigated. It is argued that the practically important effects of the flow around such bodies often depend much less on the mean flow structure than on the nature of the fluctuating flow.     

The lasting effect of words on feelings: Words may facilitate exposure effects to threatening images.

[Correction Notice: An erratum for this article was reported in Vol 8(4) of Emotion (see record 2008-12765-001). The URL provided for the supplemental materials was incorrect. The correct URL is provided in the erratum.] Previous studies have shown that mere words, particularly affective words, can dampen emotional responses. However, the effect of affective labels on emotional responding in the long term is unknown. The authors examined whether repeated exposure to aversive images would lead to more reduction in autonomic reactivity a week later if the images were exposed with single-word labels than without labels. In Experiment 1, healthy individuals were exposed to pictures of disturbing scenes with or without labels on Day 1. On Day 8, the same pictures from the previous week were exposed, this time without labels. In Experiment 2, participants were spider fearful and were exposed to pictures of spiders. In both experiments, although repeated exposure to aversive images (without labels) led to long-term attenuation of autonomic reactivity, exposure plus affective labels, but not nonaffective labels, led to more attenuation than exposure alone. Thus, affective labels may help dampen emotional reactivity in both the short and long terms. Implications for exposure therapy and translational studies are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design options for improving protective gloves for industrial assembly work

The study investigated the effects of wearing two new designs of cotton glove on several hand performance capabilities and compared them against the effects of barehanded, single-layered and double cotton glove conditions when working with hand tools (screwdriver and pliers). The new glove designs were based on the findings of subjective hand discomfort assessments for this type of work and aimed to match the glove thickness to the localised pressure and sensitivity in different areas of the hand as well as to provide adequate dexterity for fine manipulative tasks. The results showed that the first prototype glove and the barehanded condition were comparable and provided better dexterity and higher handgrip strength than double thickness gloves. The results support the hypothesis that selective thickness in different areas of the hand could be applied by glove manufacturers to improve the glove design, so that it can protect the hands from the environment and at the same time allow optimal hand performance capabilities.     

Short and longer duration effects of protective gloves on hand performance capabilities and subjective assessments in a screw-driving task

The study investigated short and longer duration effects of gloves on hand performance capabilities (muscle activity, dexterity, touch sensitivity, finger pinch and forearm torque strength) and subjective assessments of discomfort and ease of manipulation when performing a light assembly task. The independent variables were hand condition with four levels (wearing cotton, nylon or nitrile gloves as well as barehanded) and point of time within the 2 h duration of the task (with measurements taken at 0, 30, 60, 90 and 120 min). Participants worked with a screwdriver to fit two components together using screws. Wearing gloves significantly increased the muscle activity, pinch strength and discomfort but reduced the dexterity and touch sensitivity. There was also a significant effect of task time on the muscle activity, dexterity, forearm torque strength and touch sensitivity, which indicates that the duration of the task should be an important consideration in glove evaluation studies and in the selection of work gloves. STATEMENT OF RELEVANCE: It is important to evaluate the effects of gloves on hand performance capabilities in a working context so that job demands can be taken into account and the most appropriate type of glove be chosen for each task. This study gives recommendations regarding the evaluation and use of gloves for screw-driving tasks.     

A vulnerability-centric requirements engineering framework: analyzing security attacks, countermeasures, and requirements based on vulnerabilities

Many security breaches occur because of exploitation of vulnerabilities within the system. Vulnerabilities are weaknesses in the requirements, design, and implementation, which attackers exploit to compromise the system. This paper proposes a methodological framework for security requirements elicitation and analysis centered on vulnerabilities. The framework offers modeling and analysis facilities to assist system designers in analyzing vulnerabilities and their effects on the system; identifying potential attackers and analyzing their behavior for compromising the system; and identifying and analyzing the countermeasures to protect the system. The framework proposes a qualitative goal model evaluation analysis for assessing the risks of vulnerabilities exploitation and analyzing the impact of countermeasures on such risks.     

Fewest repetitions versus maximal-exponent powers in infinite binary words

A square is the concatenation of a nonempty word with itself. A word has period p if its letters at distance p match. The exponent of a nonempty word is the quotient of its length over its smallest period. In this article we give some new results on the trade-off between the number of squares and the number of maximal-exponent powers in infinite binary words, in the three cases where the maximal exponent is 7/3, 5/2, and 3. These are the only threshold values related to the question.