• Title/Summary/Keyword: physical property.

Search Result 1,883, Processing Time 0.029 seconds

Effects of Specific Frequency and Application Timing of Microcurrent on the Mechanical Property of Muscle Caused by Delayed Onset Muscle Soreness (미세전류 특정 주파수와 적용시기에 따른 지연성근육통 유발로 인한 근육의 기계적 특성변화)

  • Lee, Jeongwoo;Lee, Seul;Doo, Yeongtaek
    • Journal of The Korean Society of Integrative Medicine
    • /
    • v.7 no.2
    • /
    • pp.11-17
    • /
    • 2019
  • Purpose : The purpose of this study was to determine the effects of specific frequency and application timing of microcurrent (MC) on the mechanical property of muscle caused by delayed onset muscle soreness (DOMS). Methods : The subjects were 32 healthy adults with 8 subjects randomly assigned to four groups (I; 40 Hz MC while inducing DOMS, II; 40 Hz MC immediately after inducing DOMS, III; 284 Hz MC while inducing DOMS, IV; 284 Hz MC immediately after inducing DOMS). DOMS is applied to the biceps brachii muscle while MC was applied at an intensity of $300{\mu}A$ for 10 minutes. The mechanical properties of muscle were measured before and immediately after DOMS. Results : In terms of muscle tone, there were significant differences in interaction effects between time and groups. Regarding muscle elasticity and stiffness, there were no significant differences in interaction effects between time and groups but there were only significant differences in main effects based on time. Conclusion : The results indicated that 40 Hz MC had an effect on reducing muscle tone regardless of application timing. However, both 40 Hz and 284 Hz MC did not trigger changes in muscle elasticity and stiffness regardless of application timing.

The Analysis of Physical Characteristics and Raw Materials on Hard and Soft Whiteware at Excavated Kiln in Dudong-ri Gyeongsangnam-do, Korea (경남 두동리가마터 출토 경질과 연질백자에 대한 물성 및 원료 분석)

  • Koh, Min-Jeong;Kim, Ji-Tae;Koh, Kyong-Shin;Kim, Gyu-Ho
    • Journal of Conservation Science
    • /
    • v.18 s.18
    • /
    • pp.75-88
    • /
    • 2006
  • This study tries to find out the properties of soft ind hard white wares of white wares from Dudong-ri in a scientific way, especially by meant of physical chemical analysis, microstructural observation. As a result, In the physical analysis, soft white wares are found to have higher absorption and porosity. In the composition analysis, the chemical property, of body and glaze, shows that the composition of them varies with excavation areas. However, no clear difference is identified between the soft and hard white wares which are from the ssme kiln. The microstructural observation visibly shows the difference of hard and soft white wares which it verified in the physical property Minerals with round pores and vitrified feldspar are observed in the body of hard white wares, but no vitrified particles but widely distributed pores with long and sharp irregular shapes are found in the body of soft white wares. In conclusion, the hard and soft white wares from Dudong-ri kiln are mainly influenced by physical property and microstructural rather than chemical composition and firing atmospheres. However, more and various comparative studies are needed since the resources with various physical properties vary among kilns of each production area.

  • PDF

A Study of the Physical Properties of Weft Knit Fabrics (위편조직(緯編組織)의 물성(物性)에 관한 연구(硏究))

  • Kim, In-Suk;Lee, Soon-Hong
    • Journal of Fashion Business
    • /
    • v.2 no.4
    • /
    • pp.93-101
    • /
    • 1998
  • Knit products which had been limited only to underwear, recently became popularized, fashionized and highly classified covering even outer garments such as sportswear like golfwear, woman's dress, and man' s suit. As fashion cycle is getting shorter and the more a nation advanced prefers knit to woven fabrics knit industry has a very bright prospect, particularly woman's knit which is sensitive to fashion can be said as a fashion product with high value added. This study is to grasp the physical properties of stitch which are fundamental to the development of knit products. For this purpose, 2/20s of 100% wool were woven by the author of this study to basic plain stitch, rib stitch, varied transfer stitch, and float stitch on a SEMASEIKI cross knitter 7G to test the physical properties, and the result was as follows; 1. As for the relation between knit stitch and rate of extension recovery, rate of extension recovery was higher in the course direction than in the wale direction of three stitches except transfer stitch; rib stitch showed the highest rate of extension recovery in the course direction while float stitch showed the highest rate of extension recovery in the wale direction. 2. As for the relation between knit stitch and bursting strength elastic rib stitch showed higher bursting strength to indicate elasticity is an important factor of bursting strength and float stitch showed higher bursting strength too to indicate that the floating yarn on the surface plays a role of support. 3. As for the relation between knit stitch and air permeability perforated transfer stitch showed the lowest air permeability to prove that the size of perforation affects on the air permeability a great deal. 4. As for the relation between knit stitch and warmth retaining rib stitch through two lined needle bar showed the highest degree. The reason the warmth of perforated transfer stitch didn't decrease much was because the perforation wasn't big enough and content of air increased from the unevenness of the perforated parts through stitch variation. Based upon this result, each stitch can be characteristically summarized as follows; plain stitch showed a stable condition of knit cloth in four kinds of physical property test. And rib stitch is proper to tighten the edge of sleeve or clothe making use of its excellent extension recovery and to make socks for the highest bursting strength and warmth retaining. In the case of transfer stitch, seasonable designs can be taken by controlling the size of loop. Considering the pleasantness, underwear should be made of stitches with good air permeability float stitch was revealed to have color and pattern effects and a great bursting strength. This study has limitations in the aspect that it dealed with a small part of various knit stitches and the items of physical property test were not enough. The author of this study hopes that further studies would make deeper understandings about knit stitch based on more varied stitches and physical property tests ultimately to contribute to the development of fashionable designs proper to maximize the usage, function and originality.

  • PDF

A Comprehensive Representation Model for Spatial Relations among Regions and Physical Objects considering Property of Container and Gravity (Container 성질과 중력을 고려한 공간과 객체의 통합적 공간관계 표현 모델)

  • Park, Jong-Hee;Lim, Young-Jae
    • Journal of KIISE:Software and Applications
    • /
    • v.37 no.3
    • /
    • pp.194-204
    • /
    • 2010
  • A space, real or virtual, comprises regions as its parts and physical objects residing in them. A coherent and sophisticated representaion scheme for their spatial relations premises the precision and plausibility in its associated agents' inferencing on the spatial relations and the development of events occurring in such a space. The existing spatial models are not suitable for a comprehensive representation of the general spatial relations in that they have limited expressive powers based on the dichotomy between the large and small scales, or support only a small set of topological relations. The representaion model we propose has the following distinctive chracteristics: firstly, our model provides a comprehensive representation scheme to accommodate large and small scale spaces in an integrated fashion; secondly, our model greatly elaborated the spatial relations among the small-scale objects based on their contact relations and the compositional relations among their respective components objects beyond the basic topological relations like disjoint and touch; thirdly, our model further diversifies the types of supported relations by adding the container property besides the soildness together with considering the gravity direction. The resulting integrated spatial knowledge representation scheme considering the gravity allows the diverse spatial relations in the real world to be simulated in a precise manner in relation to the associated spatial events and provides an expression measure for the agents in such a cyber-world to capture the spatial knowledge to be used for recognizing the situations in the spatial aspects.

Changes on Physical Property of Ilmenite due to Microorganism (미생물에 의한 티탄철석의 물리적 특성 변화)

  • Park, Young Ho;Kang, Dae Wan;Kang, Seong-Seung
    • Tunnel and Underground Space
    • /
    • v.22 no.5
    • /
    • pp.321-329
    • /
    • 2012
  • Laboratory tests for measuring absorption, porosity, P-wave velocity and uniaxial compressive strength (UCS) were performed to examine weathering characteristics of ilmenite by microorganism. Physical property changes were quantitatively estimated with comparing culture period on the condition of abiotic oxidation without microorganism and biooxidation with microorganism. As a result, the measured pH during 45 days was distributed in the range from 3.82 to 4.26, on the other hand, biooxidation showed the range from 2.20 to 2.57. The measured absorption according to microorganism and culture period represented 0.052% at final stage in the case of abiotic oxidation and 0.073% in the case of biooxidation. Porosity showed 0.206% at final stage in the case of abiotic oxidation and 0.281% in the case of biooxidation. In general, the values by biooxidation showed higher than that by abiotic oxidation. Change range of P-wave velocity with culture period showed that the measured value as 1410 m/s at final stage in the case of biooxidation was lower than 1886 m/s of that in the case of abiotic oxidation. The UCS was decreased with increasing culture period in all specimens and represented 241.1 MPa at final stage in the case of abiotic oxidation and 140.0 MPa in the case of bioxidation. In conclusion, it implies that influence of physical property on ilmenite by biooxidation related with microorganism was larger than that by abiotic oxidation.

Predicting the Impact of Food Processing on the Physical Properties of Food

  • Zuo, Li;Lee, Jun-Ho
    • Preventive Nutrition and Food Science
    • /
    • v.8 no.4
    • /
    • pp.419-424
    • /
    • 2003
  • The physical properties of food playa significant role in the modeling and computation of the heat and mass transfers in basic food processing operations. With the advent of improved analytical techniques, statistical experiment design applications, computing ability and knowledge of the food physical properties of food, there have been significant advances in our ability to predict the impact of processing on the physical properties of food. This article briefly reviews our current ability to predict the influence of processing on the physical properties of food, such as water activity, moisture, color, and rheological characteristics.

Decision of Available Soil Depth Based on Physical and Hydraulic Properties of Soils for Landscape Vegetation in Incheon International Airport

  • Jung, Yeong-Sang;Lee, Hyun-Il;Jung, Mun-Ho;Lee, Jeong-Ho;Kim, Jeong-Tae;Yang, Jae E
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.48 no.5
    • /
    • pp.522-527
    • /
    • 2015
  • Decision of available soil depth based on soil physical and hydraulic properties for the $3^{rd}$ Landscape Vegetation Project in the Incheon International Airport was attempted. The soil samples were collected from the 8 sites at different depths, 0-20 and 20-60cm, for the three project fields, A, B, and C area. Physical and chemical properties including particle size distribution, organic matter content and electrical conductivity were analyzed. Hydrological properties including bulk density and water holding capacity at different water potential, -6 kPa, -10 kPa, -33 kPa, and -1500 kPa were calculated by SPAW model of Saxton and Rawls (2006), and air entry value was calculated by Campbell model (1985). Based on physical and hydrological limitation, feasibility and design criteria of soil depth for vegetation and landfill were recommended. Since the soil salinity of the soil in area A area was $19.18dS\;m^{-1}$ in top soil and $22.27dS\;m^{-1}$ in deep soil, respectively, landscape vegetation without amendment would not be possible on this area. Available soil depth required for vegetation was 2.51 m that would secure root zone water holding capacity, capillary fringe, and porosity. Available soil depth required for landscape vegetation of the B area soil was 1.51 m including capillary fringe 0.14 m and available depth for 10% porosity 1.35 m. The soils in this area were feasible for landscape vegetation. The soil in area C was feasible for bottom fill purpose only due to low water holding capacity.

Rubber Compounds with High Gas Barrier Property by Mixing Nylon 6 to Maleic Anhydride Grafted ENR 50 (무수 말레인산으로 그래프트된 ENR 50에 Nylon 6를 혼합한 기체 고차단성 고무 배합물)

  • Lim, Jong Hyuk;Cho, Ur Ryong
    • Polymer(Korea)
    • /
    • v.37 no.6
    • /
    • pp.770-776
    • /
    • 2013
  • The ENR 50 having the lowest gas permeability was blended with Nylon 6 which exhibits superior gas permeability, excellent wear resistance by using a twin-screw extruder. The blended materials showed the increased gas barrier property and physical properties, but did not yield a great synergistic effect due to low dispersion of Nylon 6 to ENR 50. To improve dispersion of Nylon 6 in the rubber matrix, maleic anhydride (MAH) was grafted to ENR 50. The grafting reaction between MAH and ENR 50 was evidenced using IR spectroscopy. The grafted and blended materials, ENR 50- g-MAH/Nylon 6 compounds, resulted in an enhanced gas barrier property and physical properties compared with compounds without MAH. The compound at 5 phr of MAH showed the highest crosslinking density and the best performances.

Heat Aging Effects on the Material Property and the Fatigue Life of Vulcanized Natural Rubber, and Fatigue Life Prediction Equations

  • Choi Jae-Hyeok;Kang Hee-Jin;Jeong Hyun-Yong;Lee Tae-Soo;Yoon Sung-Jin
    • Journal of Mechanical Science and Technology
    • /
    • v.19 no.6
    • /
    • pp.1229-1242
    • /
    • 2005
  • When natural rubber is used for a long period of time, it becomes aged; it usually becomes hardened and loses its damping capability. This aging process affects not only the material property but also the (fatigue) life of natural rubber. In this paper the aging effects on the material property and the fatigue life were experimentally investigated. In addition, several fatigue life prediction equations for natural rubber were proposed. In order to investigate the aging effects on the material property, the load-stretch ratio curves were plotted from the results of the tensile test, the compression test and the simple shear test for virgin and heat-aged rubber specimens. Rubber specimens were heat-aged in an oven at a temperature ranging from $50^{\circ}C$ to $90^{\circ}C$ for a period ranging from 2 days to 16 days. In order to investigate the aging effects on the fatigue life, fatigue tests were conducted for differently heat-aged hourglass-shaped and simple shear specimens. Moreover, finite element simulations were conducted for the specimens to calculate physical quantities occurring in the specimens such as the maximum value of the effective stress, the strain energy density, the first invariant of the Cauchy-Green deformation tensor and the maximum principal nominal strain. Then, four fatigue life prediction equations based on one of the physical quantities could be obtained by fitting the equations to the test data. Finally, the fatigue life of a rubber bush used in an automobile was predicted by using the prediction equations, and it was compared with the test data of the bush to evaluate the reliability of those equations.

Properties Evaluation on Aluminum for Die-casting(ADC 12) to Packing Case of Composite Sensor (복합센서 케이스용 알루미늄 다이캐스팅(ADC 12) 합금의 특성평가)

  • Son, Jae-Hwan;Oh, Sang-Kyun;Kim, Dong-Bae;Han, Chang-Woo
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.9 no.2
    • /
    • pp.141-145
    • /
    • 2006
  • In case of sense case manufactured by method of outage capacity, sensitivity is declined by outside effect and method of the photo electricity has a problem in transmission. therefore, packing case of composite sense should be developed to improve such a problem about influence of outside environment and its property evaluation has been performed. Mechanical property and result of analysis & test evaluation of Mat'l on aluminum die-casting(ADC 12type) Mat'l developed are as following. Tensile test piece, No. 4 of KS B 0801, has been applied to mechanical property test of Mat'l and It has been tested by method of metal mat'l tensile test(KS B 0802 : 2003). It can be found that physical property to KS(Korea Standard) is excellent. and homogeneous mechanical property appears. Test of Mat'l analysis has been performed by using OE Spectrometer, according to ASTM E 1251 : 1994 regulation. Consequently, good and homogeneous component contents classified by element to standard, except for Fe, have been obtained with coordination of Fe content as below 1.3% from composition standard of Aluminum Die-casting.

  • PDF