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101.
Custodians engage in strenuous manual labour throughout their workday. Uncertainty exists on whether kinematics or muscle activation changes as workers progress through their shift. The purpose of this study was to examine muscle activation and upper extremity kinematics during typical custodial tasks performed at the start and end of the work shift. Electromyography (EMG) of 8 torso and upper extremity muscles and motion capture of the corresponding region were collected for 10 custodial participants while they completed garbage removal, dry mopping, and vacuuming tasks at the start and end of a work shift. The start of shift assessment demonstrated larger anterior deltoid, posterior deltoid and extensor digitorum activation by up to 12.6 %maximal voluntary contraction (%MVC) (p < 0.001–0.023). Task affected mean and peak EMG in all muscles except flexor digitorum (p < 0.001–0.0293), and the greatest activation was found during vacuuming (peak <55%MVC in anterior and middle deltoid) and the heaviest garbage removal task (84% MVC peak in upper trapezius). Mopping created the lowest amounts of activation for almost all muscles. Joint range of motion (p < 0.001–0.031) in the shoulder was highest in vacuuming, while trunk flexion was largest in garbage removal tasks. This work replicated common custodial tasks in a laboratory, using actual custodial workers at times relevant to their typical work shifts. The information presented is useful for ergonomists, work tasks designers and custodial administration staff to develop guidelines for injury prevention. 相似文献
102.
A. Rodríguez Juárez H. Hernández Cocoletzi J. F. Sánchez Ramírez 《Fullerenes, Nanotubes and Carbon Nanostructures》2017,25(12):716-725
In this work are studied the electronic and structural properties of armchair boron nitride/carbon nanotubes using first principles calculations. The density functional within the generalized gradient approximation (HSEh1PBE-GGA) is used. For each composition, different bonding schemes for the construction of the hybrid systems were employed. Among them, structural stability with neutral charge was determined for the following compositions: T1: B40N35C75H20, T2: B35N40C75H20, T3: B37N38C75H20, T4 : B37N37C76H20, and T7: B35N35C80H20. All these hybrid nanotubes have high polarity; the T3, T4 and T7 are semiconductors: whereas T1 and T2 are conductor in character. The formers also have magnetic behavior. These properties together with a low-chemical potential suggest applications as nano-vehicle for drug delivery. These mixed nanotubes also have potential applications in the electronic devices based on the small work function. 相似文献
103.
Fluctuations in market demands, increased mobility of workers and changing employment practices as well as companies’ increased respect for individual differences of workers have led to the phenomenon that workers with large efficiency differences work together in the same production line in manufacturing companies. In a traditional travelling production line (TrPL), low-efficiency workers can block the work of higher efficiency workers. To increase the production capacity of a travelling line composed of workers with different efficiencies, a chasing-overtaking mechanism was established and used to achieve line production capacity and efficiency improvement. A formula to calculate the production capacity of two workers with different efficiencies was derived and validated. A simulation performed to analyse the differences between the ‘chasing-overtaking’ production line (COPL), TrPL and the classic ‘bucket brigade’ production line (BBPL) with respect to production capacity, working time utilisation and equipment utilisation demonstrated that the COPL provides good production capacity and adaptability to worker differences. Finally, the statistical analysis verified that the COPL has a higher production capacity, average worker working hour utilisation rate and equipment utilisation rate than the BBPL and TrPL. 相似文献
104.
提出了一种在铣削开式园弧槽无相同直径铣刀时,用小直径铣刀代替的近似铣削方法,并给出了有关公式及误差估计式。 相似文献
105.
Gemma M. Paech Sarah M. Jay Nicole Lamond Gregory D. Roach Sally A. Ferguson 《Applied ergonomics》2010,41(4):600-606
Shiftwork involving early morning starts and night work can affect both sleep and fatigue. This study aimed to assess the impact of different rostering schedules at an Australian mine site on sleep and subjective sleep quality. Participants worked one of four rosters;
- 4 × 4 (n = 14) 4D4O4N4O
- 7 × 4 (n = 10) 7D4O7N40
- 10 × 5 (n = 17) 5D5N50
- 14 × 7 (n = 12) 7D7N70
106.
107.
郑海燕 《数字社区&智能家居》2011,(5)
随着无线网络技术的发展,无线局域网越来越多的应用到家庭和企业等各种场合,该文介绍了无线局域网安全技术,并对无线局域网的安全维护提出了相应的措施和建议。 相似文献
108.
微博走进公安工作 总被引:1,自引:0,他引:1
杨恒毅 《网络安全技术与应用》2011,(11):77-79
微博这种新兴的网络交流方式越来越受到公众的关注,正在成为继博客之后网民们相互交流的新平台,这种集发布信息、互动交流于一体的网络工具也为公安机关所关注,各级公安机关纷纷对公安微博表现出了极大的热情,给新形势下的公安工作带来了新的契机。公安机关开设微博可以带来以下好处:首先,公安微博拉近了警民距离,提高了警察自身的公信力;其次,公安微博能使公安机关站在信息发布的制高点,及时消除谣言,还原真相;最后,公安微博能为侦查提供线索,为破案开辟新思路。总之,公安微博的开辟为公安工作带来了可喜的变化,小小的"微博110"正在为社会的稳定,人民的安居乐业贡献自己的力量。 相似文献
109.
综合型实验室是高校培养学生创新能力和提高学生综合素质的重要场地。本文从综合型实验室的建设出发,结合实际教学情况,提出从思路、硬件的角度完善实验室建设工作,通过开放和合作来促进教学发展。只有辅以完善的建设体系,采用合理有效的教学方式,才能最终增强教学能效性,培养出具有竞争力的创新型人才。 相似文献
110.