• Structural Engineering and Mechanics
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• v.65 no.4
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• pp.447-452
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• 2018

The controlling and prediction of spring back is one of the most important factors in sheet metal forming processes which require high dimensional precision. The relationship between effective parameters and spring back phenomenon is highly nonlinear and complicated. Moreover, the objective function is implicit with regard to the design variables. In this paper, first the influence of some effective factors on spring back in U-die bending process was studied through some experiments and then regarding the robustness of artificial neural network (ANN) approach in predicting objectives in mentioned kind of problems, ANN was used to estimate a prediction model of spring back. Eventually, the spring back angle was optimized using the Imperialist Competitive Algorithm (ICA). The results showed that the employment of ANN provides us with less complicated and time-consuming analytical calculations as well as good results with reasonable accuracy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.199-199
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• 2010

A back-gated MOSFET on silicon-on-insulator (SOI) substrate for pH sensor was investigated. We used concentrations of pH solution from 6 to 9. The fabricated back-gated MOSFET has current difference and threshold voltage shift by pH concentrations. Therefore, It can be used to simplification of conventional pH sensor.

• Journal of Korean Academy of Nursing
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• v.31 no.5
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• pp.770-780
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• 2001

This quasi-experimental study was to explore the effects of back massage with Lavender essence oil on the stress response of the ICU nurses. Method: Twenty nurses were selected as an experimental group and twenty nurses were in the control group. Lavender essence oil mixed with Jojova carrier oil was used to massage the neck, shoulder, back, and low back. Massage was done three times a week for 20 minutes for 2 weeks by the massage therapist. The stress response was measured with a subjective stress score, Cortisol and IgA level in saliva. The cortisol level in saliva was analyzed by an radioimmunoassay before and after back massage. The level of IgA in saliva was analyzed by an immunoturbidimeter assay and subjective stress scores was measured by Visual Analogue Scale. The data was analyzed using SPSS 8.0 and the hypotheses were tested by ANCOVA and the Pearson coefficient correlation. Result: 1) Score of subjective stress decreased significantly after the use of back massage with Lavender essence oil. 2) Level of Cortisol in saliva did not change significantly after the use of back massage with Lavender essence oil. 3) Level of IgA in saliva increased significantly after the use of back massage with Lavender essence oil. 4) After the use of back massage with Lavender essence oil, there was significant negative correlation between subjective stress and level of IgA in saliva. Conclusion: Back massage with Lavender essence oil is an effective intervention to reduce the stress response in the ICU nurses.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.258-264
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• 2015

This study was conducted to evaluate emulsion mapping between emulsion stability and cooking yields, apparent viscosity, and hardness of reduced-fat pork emulsion systems. The reduced-fat emulsion systems were supplemented with different lipid types and brown rice bran fiber (BRF) concentrations. Compared to the control with 30% back fat, lower emulsion stability and higher cooking yield of meat emulsion systems were observed in T1 (30% back fat+1% BRF), T2 (30% back fat+2% BRF), T3 (30% back fat+3% BRF), T4 (30% back fat+6% BRF), and T15 (10% back fat+10% canola oil+2% BRF). Lower emulsion stability and higher apparent viscosity were observed in T1, T2, T3, T4, and T8 (20% back fat+3% BRF) compared to the control. Lower emulsion stability and higher hardness was detected in all treatments compared with the control, except T5 (20% back fat), T10 (10% back fat+10% canola oil+2% BRF), T11 (10% back fat+10% olive oil+2% BRF), T12 (10% back fat+10% grape seed oil+2% BRF), and T13 (10% back fat+10% soybean oil+2% BRF). This approach has been found particularly useful for highlighting differences among the emulsified properties in emulsion meat products. Thus, the results obtained with emulsion mapping are useful in making emulsified meat products of desired quality characteristics, partially replacing pork back fat with a mix of 10% back fat, 10% canola oil and 2% BRF was most similar to the control with 30% pork back fat.

• Steel and Composite Structures
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• v.33 no.1
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• pp.37-66
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• 2019

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless-steel lipped channels as compression members are becoming increasingly popular. The advantages of using stainless-steel as structural members are corrosion resistance and durability, compared with carbon steel. The AISI/ASCE Standard, SEI/ASCE-8-02 and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element analyses have been reported in the literature for such back-to back cold-formed stainless-steel channels. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (gAS/NZS) standards for built-up carbon steel sections only describe a modified slenderness approach, to consider the spacing of the intermediate fasteners. Thus, this paper presents a numerical investigation on the behavior of back-to-back cold-formed stainless-steel built-up lipped channels. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404 have been considered. Effect of screw spacing on the axial strength of such built-up channels was investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns, failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines by AISI and AS/NZS. In total, 647 finite element models were analyzed. From the results of the parametric study, it was found that the AISI & AS/NZS are conservative by around 10 to 20% for cold-formed stainless-steel built-up lipped channels failed through overall buckling, irrespective of the stainless-steel grades. However, the AISI and AS/NZS can be un-conservative by around 6% for all three grades of stainless-steel built-up channels, which failed by local buckling.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.64-68
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• 2021

Objective: In clinical practice, there are a lot of exercise to reduce body weight or reduce the amount of body fat in order to solve back pain. However, many studies have contradicted the relationship between back pain and weight or body fat mass. The purpose of this study was to investigate the relationship between fat mass, body mass index and low back pain of office worker. Design: Crossed-sectional study Methods: Among the white-collar workers diagnosed with non-specific back pain by doctors, subjects who were not included in the exclusion criteria were selected to measure the subject's body fat mass, body mass index, pain intensity, and disability index due to back pain. The NPRS was used for the intensity of back pain of office workers, and the ODI was used for the degree of disability due to back pain. A body composition analyzer was used to measure the body fat mass and body mass index of white-collar workers. Results: There was no significant difference between the two groups in the comparison between the normal group and the excessive group according to the criteria of fat mass and body mass index. In the correlation analysis of fat mass, body mass index, pain intensity, and disability index, it was found that there was a significant correlation between fat mass and body mass index. However, neither fat mass nor body mass index had a significant correlation with pain intensity and disability index. Conclusions: The fat mass and body mass index of office worker do not affect low back pain.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.613-620
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• 2013

This study was conducted to measure and analyze the changes in paraspinal muscles of acute and chronic low back pain patients using MRI, and to provide clinical basic data for diagnosis and treatment for low back pain. For this purpose, 20 patients with acute low back pain frome August 2012 to January 2013 which occurred within 12 weeks, and 20 patients with chronic low back pain that progressed over 12 weeks, were chosen as subjects, and their MRI measurements were compared with one another. As a result, in relation to in the fatty degeneration ratio of the left spine and right spine, there were significant differences in erector spinae and multifidus(p<.001), and in relation to the Fat Infiltration ratio between all the groups, there were significant differences in psoas major, erector spinae and multifidus between the acute low back pain patient group and the chronic low back pain patient group(p<.001). In the post-hoc test, multifidus and erector spinae in the acute low back pain group and chronic low back pain group showed the highest Fat Infiltration ratio. The serious Fat Infiltration of multifidus and erector spinae in the chronic low back pain group led to weakened strength of muscles that stabilize the spine. In conclusion, it is considered that this study would present important data and basis in making acute and chronic low back pain patients pay more attention to multifidus and psoas major during rehabilitation exercise, and selecting a rehabilitation exercise program.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.2
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• pp.107-118
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• 2012

Objectives: This study examines the occurrence of disease resulting from low back pain and factors of working environment meaningfully influencing the occurrence of lumbago as well as analyzes '2nd Korean Working Condition Survey (KWCS)' conducted in 2010 so as to establish the prevention and improvement measures. Methods: The analysis method is that it is to compare the prevalence rate of low back pain according to working environment via odds ratio and to implement the test about the factors having the difference in working environment between low back pain group and normal group through weighted t-test. Results: As a result, it indicates that there is a meaningful difference for prevalence rate of low back pain according to age, status in employment and education level which are socio-demographical factors. The analysis in working hours shows that the period of work is a factor raising the prevalence rate of low back pain rather than weekly working hours. The analysis in the work risk factor indicates that the increase in prevalence rate of low back pain takes place to either workers with repetitive movement and continuously standing posture or those with heavy stress and emotional labour. Conclusions: Workers with low back pain have suffered from accident, depression, anxiety disorder and sleep. The factors in which the prevalence rate of low back pain decrease are to provide information on health and safety and working speed, and enough rest.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• Journal of Acupuncture Research
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• v.27 no.3
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• pp.93-104
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• 2010

Objectives : The purpose of this study is to observe the effects of work environment and low back pain on the structural and muscle strength changes in lumbar spine to helpful for preventation and cure of low back pain. Methods : Through measuring of lumbosacral angle, lumbar lordotic angle, lumbar gravity line ratio analyzed structure of lumbar spine and using Trunk Extension Flexion Program of CYBEX NORM System(cybex770+TMC, USA) analyzed Flex. PT, Ext. PT, E/F ratio of lumbar spine of company employees given a medical examination. Results : According to work environment, lumbar gravity line ratio is higher in white collar group than in blue collar group, Ext. PT is significantly lower in white collar group than in blue collar group. According to low back pain or not, lumbar gravity line ratio, Ext. PT is lower in low back pain group than in non-low back pain group. Conclusions : Work environment and low back pain effects on the structural and muscle strength changes in lumbar spine.