Notebook computer use on a desk,lap and lap support: Effects on posture,performance and comfort

This study quantified postures of users working on a notebook computer situated in their lap and tested the effect of using a device designed to increase the height of the notebook when placed on the lap. A motion analysis system measured head, neck and upper extremity postures of 15 adults as they worked on a notebook computer placed on a desk (DESK), the lap (LAP) and a commercially available lapdesk (LAPDESK). Compared with the DESK, the LAP increased downwards head tilt 6° and wrist extension 8°. Shoulder flexion and ulnar deviation decreased 13° and 9°, respectively. Compared with the LAP, the LAPDESK decreased downwards head tilt 4°, neck flexion 2°, and wrist extension 9°. Users reported less discomfort and difficulty in the DESK configuration. Use of the lapdesk improved postures compared with the lap; however, all configurations resulted in high values of wrist extension, wrist deviation and downwards head tilt.

Statement of Relevance: This study quantifies postures of users working with a notebook computer in typical portable configurations. A better understanding of the postures assumed during notebook computer use can improve usage guidelines to reduce the risk of musculoskeletal injuries     

The predictive validity of the RSI QuickScan questionnaire with respect to arm,shoulder and neck symptoms in computer workers

The aim of this study was to determine whether results from the RSI QuickScan questionnaire on risk factors for arm, shoulder and neck symptoms can predict future arm, neck and shoulder symptoms in a population of computer workers. For this prospective cohort study, with a follow-up of 24 months, 3383 workers who regularly worked with a computer were approached. Generalised estimating equations (GEE) with 6, 12, 18 and 24 months time lags were used to determine whether high exposure was related to symptoms at follow-up. The results showed that high scores on 9 out of 13 scales, including previous symptoms, were significantly related to arm, shoulder and neck symptoms at follow-up. These results provide support for the predictive validity of the RSI QuickScan questionnaire.

Practitioner Summary: The results showed that high scores on 9 out of 13 scales, including previous symptoms, were significantly related to arm, shoulder and neck symptoms at follow-up. The RSI QuickScan questionnaire may be recommended as a tool in the identification of computer workers who should be targeted with interventions aimed at prevention of future symptoms.     

西石门铁矿平面底部结构采矿方法在残矿回收中的研究与应用

介绍了西石门铁矿的生产现状，受深部开拓探放水施工进度的影响，以及总结分析上部残留矿的赋存形式，为延长西石门铁矿的服务年限，对40m中段以上的残留矿体进行回收，通过分析研究与现场的应用，推出平面底部结构采矿方法并成功应用，通过采用平面底部采矿方法，保证了残采矿有回收在安全条件下的作业，充分的回收了资源，有效的延长了矿山的服务年限。     

顶板走向高位钻孔解决上隅角瓦斯超限技术研究

上隅角是煤矿采煤工作面采空区的漏风汇集处,其瓦斯超限问题是矿井瓦斯治理中常见的问题。魏家地煤矿针对上隅角瓦斯超限问题,采取合理的顶板高位钻孔设计方法代替高抽巷,通过采取这一技术抽采裂隙带瓦斯,有效地解决采煤工作面上隅角问题,取得了很好的抽放效果。     

79m~2沉降电炉电极装置在1.5万t镍冶炼厂的应用

对79m2沉降电炉电极装置进行分析,针对以往电炉电极装置的问题进行了改造,经两年的生产实践证明,设计合理,运行可靠,经济效益显著。     

基于多元尺度法的女装造型感性语意评价

以常见女上装为研究对象,采用多元尺度法对女装造型的感性语意进行研究,得到8对具有代表性的且消费者易于感知的女装造型感性语意,为女装的造型评价和设计提供基础。     

Individual finger contribution in submaximal voluntary contraction of gripping

The objective of this study was to evaluate individual finger force and contribution to a gripping force, the difference between actual and expected finger forces and subjective discomfort rating at 10 different submaximal voluntary contraction (%MVC) levels (10–100% in 10 increments). Seventy-two participants randomly exerted gripping force with a multi-finger force measurement system. The individual finger force, gripping force and discomfort increased as %MVC levels increased. The middle and ring fingers exerted more force and contributed to a gripping force more than the index and little fingers due to their larger mass fractions of the digit flexor muscles. It was apparent at <50% MVC; however, the index finger increased its contribution and exerted even more force than expected at more than 50% MVC. Subjective discomfort supported the results of the objective measures. This could explain the conflicting findings between index and ring fingers in previous finger contribution studies.

Statement of Relevance: Hand tool design is of special interest in ergonomics due to its association with musculoskeletal disorders in the hand. This study reveals a different contribution pattern of the fingers in submaximal voluntary contraction of gripping exertion.     

汽车门框上条制件拉弯成形模具设计简

汽车门框、窗框多由各种复杂截面型材弯曲成形后焊接而成，型材截面复杂，并且形状多为空间三维曲面，该类复杂截面型材的高精度弯曲成形是制造汽车门框和窗框的关键技术。通过分析某汽车门框上条制件的成形工艺特点，综合比较各种弯曲方式后选取了张臂式拉弯成形工艺，并设计了拉弯成形模具、切断机构、冲孔及辅助成形装置，利用该模具可以成形出符合制件质量要求的车门框上条工件。     

均压通风技术在补连塔矿22306工作面的应用

针对补连塔矿22306工作面上隅角氧体积分数偏低问题,采用了均压通风技术,有效地消除了上隅角氧体积分数偏低的安全隐患;系统介绍了均压通风技术的方案及步骤,通过风量、风压及上隅角氧体积分数等指标,综合评价了均压通风的效果。结果表明:均压通风技术能较好地解决上隅角氧体积分数偏低问题,同时,本次灾害治理探索能够为同类生产实践提供重要借鉴。     

Methods to reduce the CO2 concentration of educational buildings utilizing internal ventilation by transferred air

The aim of this study is to develop internal ventilation by transferred air to achieve a good indoor climate with low energy consumption in educational buildings with constant air volume (CAV) ventilation. Both measurements of CO₂ concentration and a multi‐room calculation model are presented. The study analyzes how to use more efficiently the available spaces and the capacity of CAV ventilation systems in existing buildings and the impact this has on the indoor air quality and the energy consumption of the ventilation. The temperature differences can be used to create natural ventilation airflows between neighboring spaces. The behavior of temperature‐driven airflows between rooms was studied and included in the calculation model. The effect of openings between neighboring spaces, such as doors or large apertures in the walls, on the CO₂ concentration was studied in different classrooms. The air temperatures and CO₂ concentrations were measured using a wireless, internet‐based measurement system. The multi‐room calculation model predicted the CO₂ concentration in the rooms, which was then compared with the measured ones. Using transferred air between occupied and unoccupied spaces can noticeably reduce the total mechanical ventilation rates needed to keep a low CO₂ concentration.