• 한국의류학회지
• /
• 제23권6호
• /
• pp.853-863
• /
• 1999

the change of physical properties (thickness, weight, air permeability) and mechanical properties(abrasion resistance breaking load and displacement) of samples were determined after heat exposure by a RPP tester. The effect of exposure time and heat flux intensity on the changes and the relationship between physical properties and mechanical properties were investigated. FR treated cotton Kevlar/PBI and Nomex with different structureal characteristics were chosen for specimens. The changes of physical properties and mechanical properties were calculated based on their initial values before heat exposure. The longer exposure time and the high heat flux intensity the more changes of those properties. Heat flux intensity was more effective on the changes, The showed to be affected by an interplay of shrinkage and pyrolysis products loss. The changes of thickness and abrasion resistance showed to be higher for plain weave fabric and those of air permeabiliyt and breaking load and displacement for twill weave fabric. While FR treated cotton which have high RPP value experienced serious and detrimental changes after heat exposure Kevlar/PBI which has low RPP value showed no high changes. In conclusion it could be confirmed that when total performance of a protective clothing is estimated retention capability of physical and mechanical properties after heat exposure as well as RPP value must be considered.

• PNF and Movement
• /
• 제19권3호
• /
• pp.321-329
• /
• 2021

Purpose: The abdominal drawing-in maneuver (ADIM) is an exercise that selectively strengthens deep abdominal muscles. It is reported to be effective in strengthening those muscles when using a pressure biofeedback unit. However, multiple factors of bridge exercise seem to bring exercise result of ADIM without stabilizer as they influence execution of ADIM. Therefore, the purpose of this study was to compare changes in the thickness of deep abdominal muscles through the ADIM exercise incorporating either a stabilizer or the bridge exercise. Methods: Thirty healthy adults who had voluntarily given their consent were selected as the subjects. A diagnostic sonograph was used to measure the thickness of the subjects' transverse abdominis, internal oblique, and external oblique muscles. First, the thickness of the subjects' deep abdominal muscle was measured while maintaining the ADIM using the stabilizer. After three minutes of rest, the thickness was measured again while the subjects maintained the ADIM with the bridge exercise. Results: In both exercises, the thickness of the transverse abdominis showed a statistically significant increase, with a more significant increase while executing the ADIM using the bridge exercise. In both exercises, the thickness of the internal oblique showed a statistically significant increase, with a more significant increase while executing the ADIM using the bridge exercise. The thickness of the external oblique showed a statistically significant increase only in the ADIM using the bridge exercise. Conclusion: Though strengthening is not as selective as the ADIM using a stabilizer, the ADIM using the bridge exercise has a more increased thickness of the transverse abdominis and the internal oblique than that of the internal oblique. Based on the outcome of this study, the ADIM using the bridge exercise without a stabilizer can selectively strengthen deep abdominal muscles even more.

• 한국구조물진단유지관리공학회 논문집
• /
• 제28권2호
• /
• pp.17-26
• /
• 2024

최근 콘크리트 타설 중 구조체, 거푸집 및 동바리 사고가 계속해서 발생하고 있으며, 특히 슬래브 두께가 증가하는 다층지지 RC 구조에서 붕괴 사고가 빈번하게 발생하였다. 이전 연구에서는 모든 슬래브 두께가 일정한 경우에 대한 연구가 주로 수행되었으나 일부 슬래브의 두께가 다른 경우, 슬래브 단면 강성의 변화로 전체 슬래브 강성 비율이 달라져 시공 하중의 분포가 달라질 수 있어 이에 대한 연구가 요구된다. 이 연구에서는 슬래브 두께를 변수로 설정하여 슬래브 두께 변화가 콘크리트 강성과 구조물에 미치는 영향을 고려하여 시공 하중의 분포를 분석하였으며, 슬래브 두께가 변화하는 경우 콘크리트 재료 강성 뿐만이 아닌 슬래브 단면 강성도 시공 하중 산정에 고려되어야 함을 확인하였다. 슬래브 두께가 증가 할 경우 두께가 증가하는 층에 작용하는 최대 시공 하중과 최대 손상 변수는 크게 증가하였으며 두께 증가가 클수록 더욱 높은 비율의 시공 하중이 작용함을 확인하였다.

• The Journal of Korean Physical Therapy
• /
• 제28권5호
• /
• pp.264-268
• /
• 2016

Purpose: This study was conducted to investigate the effects on muscle thickness and balance ability after performing plank exercise on various surface types. Methods: In this study, there were thirty healthy participants. Participants were randomly distributed into three groups, a control group (n=10), sling group (n=10), and ball group (n=10). All participants performed plank exercises three times a week for four weeks. Plank exercises consisted of five sets of 30 seconds each with a one minute break between each set. Muscle thickness of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) was measured using an ultrasound diagnostic apparatus and balance was measured using I-balance. Results: Evaluation of muscle thickness revealed that the IO and EO muscle of the ball group changed significantly relative to the control group (p<0.05). However, there were no significant changes in balance. Conclusion: The results revealed that performing plank exercise on a ball is more effective among various types of surfaces.

• 한국식품영양과학회지
• /
• 제30권2호
• /
• pp.273-276
• /
• 2001

서로 다른 온도($3^{\circ}C와\;25^{\circ}C$)에서 저장한 감귤류에서의 과피 두께와 품질변화간의 상관관계를 살펴보았다. $3^{\circ}C보다\;25^{\circ}C$에서 저장한 감귤의 중량손실은 컸으나 당도(%Brix)는 저장온도에 상관없이 일정하게 증가함을 보였다. 픽셀로 표현되어지는 과육의 두께도 높은 저장온도에서 급격하게 변화됨을 보였다. 위와 같은 성분들은 시간에 따른 0차 반응속도로 분석한 결과 각 온도에서의 반응상수들이 구하여졌다. 과육의 두께를 회기선형모델에 적용한 결과, 저장기간을 예측할 수 있었고 그때의 중량감소나 당도변호가 과육 두께의 함수로 표현되어질 수 있었다.

• Restorative Dentistry and Endodontics
• /
• 제19권1호
• /
• pp.73-84
• /
• 1994

Using a model system that can compare the before and after of canal preparation in the same tooth, we measured the area of the cross section, and canal wall thickness of the distal portion of the mesial root of the mandibular molar, and compared the amount of reduction in the canal using hand flared preparation the Gates-Glidden drill flared preparation according to the changes in the MAF. The results were as follows. 1. After canal preparation, the canal wall thickness had no significant difference between the hand flared preparation and Gates-Glidden drill flared preparation. 2. The canal wall thickness, after canal preparation, there was no significant difference between the sizes of the MAF. 3. The area variation range of each cross section of root had no significant difference between MAF size and methods of canal preparation. 4. After canal preparation, the frequency of the canal wall thickness under 0.5mm showed 3.5mm below the furcation to be the most frequent with statistical significance(p<0.05). 2mm below the furcation and 5mm below the furcation followed but there was no statistical significance. 5. The danger zone of the mesial root of the mandibular molar seems to be around 3.5mm.

• The Journal of Korean Physical Therapy
• /
• 제28권6호
• /
• pp.393-397
• /
• 2016

Purpose: This study was conducted in an effort to determine the effects of various abdominal drawing-in maneuver (ADIM) on the thickness and length of the transversus abdominis (TrA) when using lumbar stabilization exercises on healthy adults. Methods: 72 healthy adults were divided into four groups of 18 subjects each, to which different ADIM methods were applied. 1) a simple ADIM exercise, 2) an ADIM with pressure bio-feedback units, 3) an ADIM exercise with sling, and 4) an ADIM exercise with sling and vibration. Changes in the thickness and sliding length of TrA were measured when ADIM was conducted in the supine position prior to exercise and again when beginning the exercises. Following exercise, changes in the thickness and sliding length of TrA were measured using the same methods. Differences in group measurements prior to and following exercise were compared using a one-way analysis of variance. A paired t-test was applied to compare the before and after differences within each group. Results: Differences in TrA thickness change revealed that the ADIM exercise with sling and vibration group showed a significant difference in measurements taken prior to and following exercise. Differences in TrA length change revealed that the ADIM exercise with sling and vibration group showed a significant difference in measurements taken prior to and following exercise. Conclusion: ADIM exercise with vibration stimulation conducted in the bridge posture while in a prone position using a sling can be recommended as an effective exercise to improve the function of lumbar TrA.

• The Journal of Korean Physical Therapy
• /
• 제31권4호
• /
• pp.193-198
• /
• 2019

Purpose: This study examined the effects of plank exercise combined with breathing and arm exercises on the external oblique, internal oblique, and transverse abdominal muscle thickness. Methods: Thirty healthy adults consisting of 12 males and 18 females from K area were divided into a plank exercise combined with breathing and arm exercises group (n = 15) and a plank exercise only group (n=15). The changes in muscle thickness before the exercise and four and eight weeks after the exercise were analyzed using a two-way repeated analysis of variance (ANOVA). The significance level was set to ${\alpha}=0.05$. Post-hoc t-tests were conducted to detect the interactions between the time and groups, and the significance level was set to ${\alpha}=0.01$. Results: According to the experimental results, the external oblique abdominal muscle showed significant differences over time (p<0.05). The internal oblique abdominal muscle also showed significant differences over time and in the interactions between the time and groups (p<0.05). The transverse abdominal muscle showed significant differences over time, in the interactions between time and groups, and in the changes between the groups (p<0.05). Conclusion: The results indicated that plank exercise combined with breathing and arm movement exercises led to increases in the abdominal muscle thickness. These types of exercises may be useful in lumbar stabilization rehabilitation treatment.

• 대한기계학회논문집A
• /
• 제22권1호
• /
• pp.238-246
• /
• 1998

Surface residual stresses as well as wall thickness and ovality changes after U-bending process on UNS N06690 row-1 heat exchanger tubes, were estimated. Surface residual stresses were measured by Hole Drilling Method(HDM), calculating the stresses from relieved strains of 3 rosette strain gages. After bending of the tubes, dimensional tolerances for wall thickness and ovality were satisfied with ASTM requirements. Residual stresses at the extrados were introduced with compressive stress(-) by bending operations, and its maximum value reached-319 MPa in axial direction at ${\phi}=0^{\circ}$ in position. Tensile residual stresses(+) of ${\sigma}_zz=45$ MPa,${\sigma}_zz=25$ MPa were introduced in the intrados surface at position of ${\phi}=0^{\circ}$ Maximum tensile residual stress of 170 MPa was detected on the flank side at position of ,${\phi}=95^{\circ}$i.e., at apex region. It appeared that higher stress gradients were generated at the irregular transition regions. In the trend of residual stress changes with U-bend position, the extrados is related with the changes of ovality and the intrados is related with the changes of wall thickness.

• The Journal of Korean Physical Therapy
• /
• 제27권5호
• /
• pp.281-286
• /
• 2015

Purpose: The study was to determine whether mechanical horseback-riding training according to velocity may improve trunk muscles thickness in healthy adults. Methods: Twenty healthy adults participated in this study. The subjects were divided into 2 groups as follows: 10 subjects in high velocity mechanical horseback-riding training (MHRT) and 10 subjects in low velocity MHRT. Subjects in all groups performed a total of 18 sessions 3 times a day for 20 minutes and this experiment lasted for 6 weeks. Mann-Whitney and Wilcoxon Signed Rank test were used in analysis the results of trunk muscle thickness. Ultrasonography was performed to evaluate for thickness of rectus abdominis (RA), external oblique (EO), internal oblique (IO), transverse abdominis (TrA), erector spine (ES), and multifidus (MF) in trunk muscles. Results: Results on the changes of EO, IO, and ES of high velocity MHRT showed a significant increase after 6 weeks (p<0.05). Regarding the changes of EO, IO, ES, TrA, and MF of low velocity MHRT, a significant increase was observed after 6 weeks (p<0.05). The differences in change of trunk muscle thickness before training, after 6-week training between groups, TrA and MF of low velocity MHRT were significantly higher (p<0.05). Conclusion: Based on the results of the current study, the velocity of MHRT was shown to affect change of trunk muscle thickness in healthy adults. In particular, low velocity MHRT may serve as a useful method to provide for TrA, MF thickness improvement related to trunk stabilizers.