• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.5
• /
• pp.713-722
• /
• 2004

This study examined the effects of two kinds of functional sun hats through a head-manikin test and a climatic chamber trial for farm workers in summer. Experiment was composed of four conditions. The first condition was the condition without any hat (Control). The second was the condition with a sun hat on the market (Hat A). The third was the condition with a functional sun hat made of reflective fabric (Hat B). The last was the condition with a functional sun hat having a ventilating structure as well as reflective fabric (Hat C). For the subjects in the climatic chamber trials, 12 healthy males volunteered. Air temperature, relative humidity and globe temperature in the chamber was maintained at $33{\pm}0.5^{\circ}C,\;65{\pm}5%RH\;and\;39{\pm}1^{\circ}C\;(WBGT\;33^{\circ}C)$. Subjects did a simulated red pepper-work (50-min work and 10-min rest, twice repetition) for 120 min. As the result of head-manikin test, the surface temperature on middle of back-neck was the lowest in Hat B of four conditions and the surface temperature on top of head was the lowest in Hat C. As the result of climatic chamber trials, there were apparent differences between with (Hat A, Hat B, Hat C) and without a sun hat (Control). In rectal temperature ($T_{re}$), mean skin temperature ($\={T}_{sk}$), heart rate (HR), total sweat rate (TSR), The physiological heat strain was less in the condition with hats than in the condition without a sun hat. As the increasing rate in Tre, Hat B is the most effective hat for alleviation heat strain. As the subjective responses, Hat B was the most effective hat for thermal comfort even though the difference was not significant. Hat C was less effective than Hat B and the reason might be the increase of weight due to inserting the ventilating structure.

• Fashion & Textile Research Journal
• /
• v.8 no.3
• /
• pp.349-356
• /
• 2006

The purpose of this study was to compare the thermophysiological responses and subjective sensations of clothing materials with different water transfer property investigated in exercising and resting subjects at an ambient temperature of $20^{\circ}C$ and a relative humidity of 40%. Two kinds of clothing ensemble were tested: 100% cotton with highly water-absorbent but slowly dry properties(C) and 100% polyester with quickly water-absorbent and dry properties by four capillary channels(QADP). Seven apparently healthy male participants each undertook two series of experiments comprised 10-min of rest, 20-min of exercise with 70% of $VO_{2max}$ on a treadmill and 20-min of recovery. Mean skin temperature was significantly lower in QADP than in C during exercise and recovery. Clothing microclimate temperature was significantly lower in QADP during exercise and clothing surface temperature was also lower in QADP especially during recovery. Also, clothing surface humidity was significantly higher in QADP after the later half of exercise. The concentration of blood lactic acid tended to decrease to a lower level at recovery 3 minutes when wearing QADP rather than C clothing ensemble. Metabolic energy was marginally significantly less during the second half of exercise in QADP. Body mass loss tended to be greater in C than in QADP. The participants had better scores in thermal sensation, comfortable sensation and wetness in QADP during exercise and recovery. These results show that functional materials with quickly water-absorbent and dry properties can alleviate heat strain and induce more comfortable clothing microclimates and subjective sensations in the exercise-induced hyperthermia.

• Journal of Cardiovascular Imaging
• /
• v.31 no.4
• /
• pp.191-199
• /
• 2023

BACKGROUND: Assessment of left ventricular (LV) function plays a pivotal role in the management of patients with valvular heart disease, including those caused by rheumatic heart disease. Noninvasive LV pressure-strain loop analysis is emerging as a new echocardiographic method to evaluate global LV systolic function, integrating longitudinal strain by speckle-tracking analysis and noninvasively measured blood pressure to estimate myocardial work. The aim of this study was to characterize global LV myocardial work efficiency in patients with severe rheumatic mitral stenosis (MS) with preserved ejection fraction (EF). METHODS: We retrospectively included adult patients with severe rheumatic MS with preserved EF (> 50%) and sinus rhythm. Healthy individuals without structural heart disease were included as a control group. Global LV myocardial work efficiency was estimated with a proprietary algorithm from speckle-tracking strain analyses, as well as noninvasive blood pressure measurements. RESULTS: A total of 45 individuals with isolated severe rheumatic MS with sinus rhythm and 45 healthy individuals were included. In healthy individuals without structural heart disease, the mean global LV myocardial work efficiency was 96% (standard deviation [SD], 2), Compared with healthy individuals, median global LV myocardial work efficiency was significantly worse in MS patients (89%; SD, 4; p < 0.001) although the LVEF was similar. CONCLUSIONS: Individuals with isolated severe rheumatic MS and preserved EF, had global LV myocardial work efficiencies lower than normal controls.

• Journal of the Korea Concrete Institute
• /
• v.25 no.6
• /
• pp.593-599
• /
• 2013

The unrestrained shrinkage strain of alkali-activated (AA) slag concrete was examined and compared with design equations specified in code provisions and empirical equations proposed by Yang et al. The main parameters investigated were the water-to-binder ratio (W/B), unit water content and fine aggregate-to-total aggregate ratio (S/a). Test results revealed that shrinkage strain of AA slag concrete is nearly proportional to the W/B ratio, whereas its time function is independent of the W/B ratio. The shrinkage strain of AA slag concrete increased significantly when the unit water content is above $185kg/m^3$, whereas it is marginally affected by the S/a ratio. The design equation of ACI 209 considerably overestimates the shrinkage behavior of AA slag concrete, whereas CEB-FIP equation tends to underestimate the shrinkage at the age more than 28 days. The empirical equation of Yang et al. is in better agreement with test results, showing that values of mean and standard deviation of error coefficients obtained from each specimen are 016 and 0.07, respectively.

• Transactions of Materials Processing
• /
• v.11 no.1
• /
• pp.69-74
• /
• 2002

In addition to lightweight and moldable characteristics, polymeric foams possess an excellent energy absorbing capability that can be utilize for a wide range of commercial applications, especially in the crashworthiness of the automobiles. The purpose of the present study is to develop experimental methodology to characterize the pressure dependent yield behavior of the energy absorbing polymeric foams. For the compression test in a triaxial stress sate, a specially designed device was placed in a hydraulic press to produce and control oil pressure. For the test material, the polyurethane foams of two different densities were used. The displacement of the specimen, the load subjected to the specimen, and oil pressure applied to the specimen were measured and controlled. Stress strain curves and yield stresses for the four different oil pressure were obtained. It was found from the present experiments that the polyurethane foams exhibited significant increases in yield stress with applied pressure or mean normal stress. Based on this observation, a yield criteria which included the effect of the stress invariant were established for the polymeric foams. The obtained experimental constants which constituted the pressure-dependent yield criterion were verified.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.1 no.1
• /
• pp.105-112
• /
• 1995

This study was designed to investigate the efficiency of subjective assessment that exams the subjective symptom of patients with back pain at the department of physical therapy. To assess the subjective symptom, we used the pain questionnaire using visual analogue scale (VAS) that was developed by Wang on 1995. Questionnaires were administered to 31 adult patients(male : 11, female : 20) with herniated lumbar disk(13), low back pain(8), myofascial pain syndrom(5), lumbar strain(4), ankylosing spondylitis(1). Mean age was 36.3 ranged from 20 to 65. The results of this study were as follows : 1) In each of 15 subjects, there was a significant decrease in VAS between pre- and post-treatment(p<0.05). 2) Mean VAS of total subjects was $6.26{\pm}2.55$ in pre-treatment, $4.50{\pm}2.47$ in post-treatment (p<0.001). Result of this study was shown efficiency of pain management by subjective assessment. The continuous study is needed for many interesting illue of pain management using VAS.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.9
• /
• pp.2206-2222
• /
• 1995

In this study, the characteristics of the three-dimensional turbulence flow in a rotating square sectioned 90.deg. bend were investigated by numerical simulation. And a dimensionless number, Coriolis force ratio, primarily subjected to the feature of the flow in the rotating 90.deg. bend was obtained as a result of one-dimensional theory. In the simulation study, low Reynolds number ASM developed by Kim(1991) in the square sectioned 180.deg. bend flow was modified in order to consider the rotational effects in the testing flows. In the near wall region of low Reynolds number, four turbulence models were employed and compared in order to find the most appropriate model for the analysis of the rotating 90.deg. bend flow. By comparison of the results with the experimental data, it is shown that low Reynolds number Algebraic Stress Model with rotating terms reflects most correctly the rotational effects. As the results of this study, centrifugal forces associated with the curvature of the bend and Coriolis forces and centripetal forces associated with the rotation affect directly both the mean motion and the turbulent fluctuations. Their actions on the mean flow are to induce a secondary motion while their effects on turbulence are to modify the pressure strain.

• Journal of Korean Physical Therapy Science
• /
• v.2 no.3
• /
• pp.679-689
• /
• 1995

This study was designed to investigate the efficiency of subjective assessment that exams the subjective symptom of patients with back pain at the department of physical therapy. To assess the subjective symptom, we used the pain questionnaire using visual analogue scale(VAS) that was developed by Wang on 1995. Questionnaires were administered to 31 adult patients(male : 11, female: 20) with herniated lumbar disk(13), low back pain(8), myofascial pain syndrom(5), lumbar strain(4), ankylosing spondylitis(1). Mean age was 36.3 ranged from 28 to 65. The results of this study were as follows: 1) In each of 15 subjects, there was a significant decrease in VAS between pre-and post-treatment(p < 0.05 -p<0.001). 2) Mean VAS of total subjects was $6.26{\pm}2.55$ in pre-treatment, $4.50{\pm}2.47$ in post-treatment(p < 0.001). The result of this study was shown efficiency of pain management by subjective assessment. The continuous study is needed for many interesting issue of pain management using VAS.

• Journal of Aquaculture
• /
• v.12 no.4
• /
• pp.267-274
• /
• 1999

A rotifer starin has been isolated from tide pools located near Sogwipo, Cheju Island and the effects of environmental factors (water temperature and salinity) and clonal differences have been examined with regard to size variation and cyclomorphosis. Adult female rotifers varied from 141.61 to $173.97 \mutextrm{m}$ in their mean lorica length under different rearing conditions in the laboratory and also had pointed anterior spines . Thus, this strain was classified as Brachionus rotundiformes. Mean lorica length tended to be smaller as rearing temperature increased although there were some exceptions. Statistical analysis indicated that lorica length was largely influenced by both clonal differences and rearing temperatures although the former as a genetic factor affected lorica length a little more than the latter did ; overall effect of salinity on lorica length was not statistically signicicant; furthermore, cyclomorphosis was also largely influenced by both clonal differences and rearing temperatures, but clonal differences as a genetic factor affected rotifer cyclomorphosis much more than temperature did.

• Korean Journal of Occupational Health Nursing
• /
• v.6 no.1
• /
• pp.5-13
• /
• 1997

For the purpose of investigating the subjective symptom of industrial fatigue, a questionnaire survey was carried out on 282 labor workers and 189 managerial workers who were employed at the manufacture of electronic products in two small scale industries. Checklist of industrial fatigue was composed of physical symptoms(10 items), mental symptoms(10 items), and sensory neurotic symptoms(10 items). The results were as follows : 1. Complain rate of fatigue was the highest in "eye strain" of physical symptom, "feel anxious about things" of mental symptom, and "feel stiffness in the neck or the shoulders" of sensory neurotic symptom in labor workers and managerial workers. 2. Managerial workers demonstrated II dominant type (mental or night work type), while labor workers demonstrated I dominant type of fatigue (general type). 3. Mean weighted score of fatigue complaints in labor workers (23.16) was significantly higher than that in managerial workers (20.34). 4. Mean weighted scores of fatigue complaints in male, 5~9 years of work duration, married, 4~5 hours of sleeping time, graduation of high school and college, and large of workload were significantly higher in labor workers than in managerial workers. 5. In poor work condition with temperature, ventilation, illumination and noise, the average weighted score was significantly higher in labor workers than in managerial workers.