• Title/Summary/Keyword: elastic body

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Comport Sensation of Blue Jeans depending on Fiber Contents (청바지의 소재별 쾌적감에 관한 연구)

  • 홍문경;이미식;권계화;전정애
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.2
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    • pp.237-248
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    • 2001
  • The purpose of this study was to compare the comfort sensation depending on four different kinds of denim blue jeans: cotton, cotton/tencel, tencel, cotton/pp. The objective and subjective experiments were conducted to measure the comfort of blue jeans. To investigate the objective comfort, physical properties related to thermal insulation, moisture properties and hand were measured. For subjective comfort measurement, 5 healthy female college students were taken as subjects. The outcomes of the experiments are as follows: The higher the air permeability and bulk density of the denim, the lower the thermal insulation, the thicker the denim, the higher the thermal insulation. Tencel blending denim showed the higher bulk density, the lower air contents, and consequently the lower thermal insulation than the other denims. Tencel showed the highest moisture regain, and cotton/tencel blend showed the highest water vapor permeability. Tencel denim had relatively better flexibility, shape stability and elastic recovery than the other denims. The total hand values of the denims by KES-FB system were not significantly different. Cotton and cotton/pp denims raised the subjects body temperature after excercise more than tencel or cotton/tencel denims. Average skin temperature was found to have a correlation with micro climate temperature and micro climate humidity. The correlation coefficients were 0.749 and 0.767, respectively. However, average skin temperatures were not significantly different among the materials. Pulse rate was found to be the highest when wearing cotton/pp and the lowest in case of cotton/tencel denim. The energy was consumed in order of cotton>cotton/pp>tencel>cotton/tencel. There was no significant difference in preference before excercise, but, after the excercise, the order of preference changed as the following; cotton/tencel>tencel>cotton/pp>cotton.

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Pattern Development of Tight-fitting Pants for Men Using Measurements of Size Korea 2004 (Size Korea 2004의 한국인 인체치수를 이용한 남성용 밀착 팬츠 패턴 개발)

  • Jeong, Yeon-Hee
    • Korean Journal of Human Ecology
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    • v.15 no.5
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    • pp.791-802
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    • 2006
  • The construction of athlete's tight-fitting garments by reducing the elastic knit pattern is an interesting subject, which directly influences the performance of the wearer. Therefore, relationships between the reduction rates of the men's pants pattern obtained using measurements of Size Korea 2004 and clothing fitting were explored to improve clothing comfort. Two pattern making methods were developed and the reduction rates were applied to those pants depending on the parts of human body. The four male subjects were university students in the ages of 20 to 24. Subjective wear sensations of the experimental garments were rated using seven Likert scales during 4 consecutive days. While wearing the garments, subjects were kept four various postures including waist flexion and sitting etc by requests of the researchers. Likert type scale was used for the evaluation and 7 point indicates that it gave the best fit as tight-fitting pants. As results, differences in the length and girth between two piece pants pattern(style 1) and one piece pants pattern(style 2) were 0.0$\sim$0.3cm. Between two pattern making methods, one piece pants pattern(the style 2) was superior to two piece pants pattern in terms of subjective sensation and fit. Among eight tight-fitting pants, C, D, G, H pants were superior in terms of fitting and stability of waist and hip part to the others. ill case of tight-fitting pants, the reduction rate of the pattern in the course direction, the reduction rate of T2/3(66%) was better than that of T/2(50%), but the reduction rate of the pattern in the wale direction, that of the part of crotch, which was very sensitive part, should be kept the same as suggested earlier by Ziegert(1988).

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Rheological Evaluation of Petroleum Jelly as a Base Material in Ointment and Cream Formulations : Linear Viscoelastic Behavior

  • Park, Eun-Kyoung;Song, Ki-Won
    • Journal of Pharmaceutical Investigation
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    • v.41 no.3
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    • pp.161-171
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    • 2011
  • The objective of the present study is to systematically characterize a linear viscoelastic behavior of petroleum jelly in small amplitude oscillatory shear flow fields correspondent to the rheological ground state. With this aim, using a strain-controlled rheometer, the dynamic viscoelastic properties of commercially available petroleum jelly have been measured at $37^{\circ}C$ (body temperature) over a wide range of angular frequencies at an extremely small strain amplitude of 0.1 %. In this article, the linear viscoelastic behavior was reported in detail and then explained from a structural view-point of petroleum jelly and discussed in depth with respect to the consumer's requirements. Main findings obtained from this study can be summarized as follows : (1) The storage modulus is always greater than the loss modulus over an entire range of angular frequencies studied, meaning that the linear viscoelastic behavior of petroleum jelly is dominated by an elastic nature rather than a viscous nature. (2) Petroleum jelly shows a desirable linear viscoelastic behavior with respect to the consumer's requirements because it is undesirable for the product to flow down from the skin at an initial stage upon contact with the human skin. (3) A fractional derivative model shows an excellent applicability to describe a linear viscoelastic behavior of petroleum jelly. However, this model should be used with a special caution because there exists no physical meaning for the model parameters. (4) A modified form of the Cox-Merz rule gives a good ability to predict the relationship between steady shear flow properties (nonlinear behavior) and dynamic viscoelastic properties (linear behavior) for petroleum jelly.

A MECHANICAL INVESTIGATION OF CORNEAL REFRACTIVE SURGERIES AND PROPOSITION OF NEW TECHNIQUES (각막굴절수술의 역학적 고찰 및 새로운 기법의 시도)

  • Shin, J.W.;Han, G.J.;Whang, M.C.;Nam, S.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1995 no.05
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    • pp.95-100
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    • 1995
  • This study investigated the effects of mechanical factors involved in several corneal refractive surgeries on the surgical outcomes. Then we proposed possible new techniques from the mechanical point of a view utilizing finite element method. The models studied are: circumferential keratetomy, combination of excimer laser photorefractive keratectomy and circumferential keratotomy for myopia treatment, arcuate keratotomy for astigmatism treatment. The cornea was assumed to be nonlinear elastic and almost incompressible material as the most soft tissue in the human body. In the circumferential keratotomy the effect of the incision location was investigated. The angle and location of the incision were varied to predict the surgical outcomes in the arcuate keratotomy. The finite element analysis results showed that the location of incision was a critical factor affecting the surgical outcomes in the circumferential keratotomy. In the combination of the excimer laser photorefractive keratectomy and circumferential keratotomy, it was predicted that the circumferential can increase or decrease the refractive power depending on the incision location or it can be used to adjust the overcorrection of undercorrection. In the arcuate keratotomy for astigmatism, the most diopter changes were predicted when the location and the angle of the incision were 3.0mm from the apex and $90^{\circ}$, respectively. In the arcuate keratotomy, the effects of an incision were studied within the incision area as well as outside the incision area. Also, the arcuate keratotomy with two incisions located on the opposite area of the cornea was also studied. As a conclusion, the finite element method is a useful technique in the area of corneal refractive surgeries to develop new techinques.

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Flocculation of Red Tide Organisms in Sea Water by Using an Ignited Oyster Shell Powder and Loess Combination (소성굴패각분말과 황토의 동시 사용에 의한 적조생물의 응집)

  • KIM Sung-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.6
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    • pp.716-722
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    • 2003
  • This study determined the optimum dosage for coagulation reactions of red tide organisms (RTO) using a combination of ignited oyster shell powder (10sp) and loess and examined the electrokinetic and rheological characteristics of their flocs. Two kinds of RTO, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan Bay and cultured in the laboratory. Coagulation experiments were conducted using various concentrations of IOSP, loess, IOSP+1oess, RTO, and a jar tester RTO cell numbers were counted for both the supernatant and RTO culture solution. The removal rates increased rapidly with increasing IOSP concentrations up to 50 mg/L and loess concentrations up to 800 mg/L. A removal rate of $100\%$ was reached at 400 mg/L of IOSP and 6,400 mg/L of loess. The highest increment $(16.7\%)$ of the rates of coagulation reaction occurred using both IOSP and loess (50+200 mg/L) in comparison with IOSP alone. The rate of coagulation reaction using both IOSP and loess (50+200 mg/L), $90.6\%,$ was similar to employing either IOSP of 150 mg/L or loess of 3,200 mg/L. All of the coagulation liquids for RTO, IOSP (200 mg/L), loess (200 ma/L), and IOSP+1oess (200+200 mg/L) revealed non-Newtonian fluid properties and therefore their shear rate vs. shear stress curves were non-linear. The coagulation liquids revealed elastic body properties at a lower shear rate increasing in the following order: RTO, IOSP (200 mg/L), loess (200 mg/L), and IOSP+1oess (200+200 mg/L. IOSP+1oess (200+200 mg/L) especially demonstrated plastic flow properties at a lower shear rate.

The Most Effective Number of Elastic Taping Applications on the Muscle Activity and Maximum Peak of the Wrist Extensor Muscle in Patients with Stroke

  • Cho, Ju Chul;Lee, Byoung Kwon;Chon, Seung Chul
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.6
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    • pp.533-541
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    • 2014
  • Objective: The aim of this study is to evaluate the differences in electromyographic activities of upper extremity muscle between repeated taping and to compare the effects of each taping method in stroke patients. Background: Taping studies for functional improvement and pain relief of the UE have been conducted using various methods. Despite being an important factor when you treatment to a patient in a clinical attachment numbers situation quantitative research is that there is not at all to the taping at the time of application. Method: Twenty patients volunteered in this study and were tested under four taping conditions as follows, in random order: (1) no taping, (2) taping applied once, (3) taping applied twice, and (4) taping applied thrice. The muscle activity and maximum peak of the extensor carpi radialis muscle in electromyographic activities were measured, respectively. Results: The muscle activity and maximum peak of the extensor carpi radialis muscle showed significant differences among the four conditions (p<.05). In the post hoc test, the extensor muscle showed significant differences in muscle activity and maximum peak in electromyographic activities, except between taping applied twice and thrice. Conclusion: These findings demonstrate that repeated taping up to two times may be useful in improving the muscle activity and maximum peak of the extensor muscle. Application: This study provides useful information to future researchers regarding the effects of repeated taping applications on muscle activity and maximum peak of the muscles of the human body.

Analysis of Semi-Rigid Connections on 3D Floating Structures (3차원 플로팅 구조물의 반강접 접합부 해석)

  • Park, Jong-Seo;Song, Hwa-Cheol
    • Journal of Navigation and Port Research
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    • v.36 no.3
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    • pp.175-180
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    • 2012
  • The shape of floating superstructure is the same as other buildings, but the foundation is based not on land but on a floating body. Unlike inland structures, they are largely influenced by the wave load. Deformation of the floating pontoon due to the wave loads affects the connection, which in turn causes problems related to the habitability and safety to the superstructure users. Accordingly, this study conducted elastic analysis regarding rigid connection and semi-rigid connection by the integration analysis that combined together the superstructure and pontoon of the 3-D floating structure. Moreover, this study investigated the results of the separation analysis excluding pontoon and the integration analysis. In addition, elasticity analysis was used to divide up the wave loads cases, and to classify the moment and displacement of the structure depending on connection following the changes in the wave loads.

Fuzzy Vibration Control of 3 DOF Robot Manipulator with Flexible Link (유연한 링크를 가진 3자유도 로봇조작기 진동의 펴지제어)

  • Kim, Jae-Won;Yang, Yang, Hyun-Seok;Park, Park, Young-Pil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.12
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    • pp.3883-3891
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    • 1996
  • Performance and productivity of robot manipulator can be improved by increasing its working speed and extending its link length. But heavy weght of the commercial robot links, considered as "rigid body", limits its mazimum working speed and the weght of the links can be reduced for high speed operation. But this light-weight link or long link for special use cannot be consideredas "rigid" structure and vibration of the link due to its flexibility causes errors in end-effector position and orientation. Thus the elastic behaviro of the flexible link should be taken care of for increasing work speed and getting smaller error of end-effector position. In this paper, the fuzzy control theory is selected to design the controller which controlos the joint positions of the robot manipulator and suppress the vibration of flexible link. In the forst place, for the 1 DOF flexible link system, the fuzzy control theory is implemented. The contdroller for the 1 DOF flexible link system is designed. Experimental research is carried out to examine the controllability and the validity of the fuzzy control theory based controller. Next, using the extended desing schemes for the case of the 1 DOF flexible link system and usign the experimental phenomena of the 3 DOF flexible link system, the fuzzy controller for the 3 DOF flexible link system is desinged and experimented.ed and experimented.

Characteristics of a new cultivar Pleurotus ostreatus, Hwaseong #2 (신품종 느타리버섯 '화성2호'의 특성)

  • Lee, Jeong-Woo;Han, Yong-Sik;Han, Chul-Hee;Jeong, Chong-Chun
    • Journal of Mushroom
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    • v.9 no.3
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    • pp.96-100
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    • 2011
  • MST247ns(Hwaseong #2) was developed by the method of Di-mon mating between monokaryotic strains derived from "Hwaseong #1" and dikaryotic strain "Suhan #1". The optimum temperature of mycelial growth was $25-30^{\circ}C$. The optimum temperature of primordia formation and fruiting body development were $8-15^{\circ}C$ and $9-14^{\circ}C$. Days of primordia formation were 4-5 days later Suhan #1. The stipes were longer than "Suhan #1". The surfaces of stipe were white and the tissues got harder and more elastic. Therefore, the management of growth environment under low temperatures was relatively easy and storability got much better.

The Phase-velocity Dispersion Characteristics of Love Wave and Rayleigh Wave in the Half Space and Multi-layered System (반무한체와 다층구조 지반에서 러브파 및 레일레이파의 위상속도 분산특성)

  • 이일화;조성호
    • Journal of the Korean Geotechnical Society
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    • v.20 no.1
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    • pp.61-73
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    • 2004
  • Rayleigh wave and Love wave are the major elastic waves belonging to the category of the surface wave. The fact that Love wave is not contaminated by P-wave makes Love wave superior to Rayleish wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than the information of Rayleigh wave. In this study, for the purpose of employing Love wave in the SASW method, the dispersion characteristics of the Love wave were extensively investigated by the theoretical, numerical and experimental approaches. The 2-D and 3-D finite element analyses for the half space and two-layer systems were performed to determine the phase velocities from Love wave as well as from both the vertical and the horizontal components of Rayleigh wave. Also, the SASW measurements were performed at the geotechnical sites to verify the results obtained by the numerical analysis. The results of the numerical analysis and the field testing indicated that the dispersion characteristics of Love wave can be an extended information to make better evaluation of the subsurface stiffness structure by SASW method.