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Wichai Eungpinichpong Vitsarut Buttagat Pattanasin Areeudomwong Noppol Pramodhyakul Manida Swangnetr David Kaber Rungthip Puntumetakul 《Applied ergonomics》2013
The objective of this study was to examine the effect of wearing restrictive trousers on lumbar spine movement, trunk muscle activity and low back discomfort (LBD) in simulations of manual material handling (MMH) tasks. Twenty-eight young adults participated in the study performing box lifting, liquid container handling while squatting, and forward reaching while sitting on a task chair when wearing tight pants (sizes too small for the wearer) vs. fit pants (correct size according to anthropometry). Each task was repeated three times and video recordings were used as a basis for measuring lumbar range of motion (LRoM). The response was normalized in terms on baseline hip mobility. Trunk muscle activity of rectus abdominis (RA) and erector spinae (ES) muscles were also measured in each trial and normalized. At the close of each trial, participants rated LBD using a visual analog scale. Results revealed significant effects of both pants and task types on the normalized LRoM, trunk muscle activity and subjective ratings of LBD. The LRoM was higher and trunk muscle (ES) activity was lower for participants when wearing tight pants, as compared to fit pants. Discomfort ratings were significantly higher for tight pants than fit. These results provide guidance for recommendations on work clothing fit in specific types of MMH activities in order to reduce the potential of low-back pain among younger workers in industrial companies. 相似文献
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Sirirat Wacharawichanant Angsumon Sangkhaphan Niramon Sa‐Nguanwong Vitsarut Khamnonwat Supakanok Thongyai Piyasan Praserthdam 《应用聚合物科学杂志》2012,123(6):3217-3224
The effects of particle size of titanium dioxide (TiO2) on mechanical, thermal, and morphological properties of pure polyoxymethylene (POM) and POM/TiO2 nanocomposites were investigated and compared with the results for nanoparticle ZnO in the same matrix, reported in a previous paper. POM/TiO2 nanocomposites with varying concentration of TiO2 were prepared by the melt mixing technique in a twin screw extruder, the same method that used for blending the homogeneous ZnO nanocomposites. The dispersion of TiO2 particles in POM nanocomposites was studied by scanning electron microscopy (SEM). The agglomeration, as observed by the mechanical properties of TiO2 particles in the polymer matrix, increased with increasing TiO2 content, a result not found for ZnO even at lower particle sizes. Increasing the filler content of POM/TD32.4 and POM/TD130 (130 nm) nanocomposites resulted in a decrease in tensile strength. The Young modulus, stress at break and impact strength of TiO2 nanocomposite did not improve with increasing filler contents, in opposition to the better agglomeration conditions of ZnO nanocomposite even at lower particle sizes. Because of agglomeration, the POM/TD32.4 nanocomposites had lower mechanical properties and lower degradation temperature than the POM/TD130 ones. The sizes of nanoparticles determined the agglomeration, but however, the agglomeration also depended on the type of nanoparticles, even when using the same matrix (POM) and the same mixing method. TiO2 nanoparticles were more difficult to mix and were more agglomerated in the POM matrix as compared to ZnO nanoparticles, regardless of the size of the nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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