• Title/Summary/Keyword: Physical density

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A Study on the Physical and Mechanical Properties of the Board Composed of Wood Particle and Steel Wire (목재(木材)파아티클과 철선복합(鐵線複合)보오드의 물리적(物理的) 및 기계적(機械的) 성질(性質)에 관(關)한 연구(硏究))

  • Park, Heon
    • Journal of the Korean Wood Science and Technology
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    • v.16 no.3
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    • pp.22-37
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    • 1988
  • In tendancy of manufacturing beam with laminating particleboard, it was thought that if the properties, especially mechanical properties, of particleboard be reinforced, the mechanical properties of particleboard-laminated beam would be also improved. So in this study the particleboard was reinforced with composing of wood particle and steel wire. This study was carried out to obtain the basic physical and mechanical properties of board composed of wood particle and steel wire, especially tensile strength and compressive strength which are the important factors of the lamina of beam, in order to estimate whether the board, composed of wood particle and steel wire could be to improve the properties of the particleboard- laminated beam. The results obtained were summarized as follows: 1. The board composed of wood particle and steel wire in accordance with lower board density took better thickness swelling. 2. The board with lower board density was improved in higher value of tensile strength with more steel wires in prescribed cross section area of the board. for example, the board of density 0.5 showing 140% improved value. 3. In compressive strength, the board with lower board density was also improved in hjgher value with more steel wires in prescribed cross section area.

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A Study of Correlation among Bone Mineral Density, Body Composition and Body Circumference on 20's Women

  • Lee, Sang-Min;Wang, Joong-San;Park, Sung-Kyu;Kim, Hong-Rae;Ko, Jin-Hee;Oh, Yu-Jung;Yoon, Hae-Ran;Kim, Ji-Sung
    • Journal of International Academy of Physical Therapy Research
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    • v.3 no.1
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    • pp.383-390
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    • 2012
  • The aim of this study was to investigate the correlation among bone mineral density(BMD), body composition and body circumference on 20's college women in Hwaseong. A total of 86 subjects were measured with BMD and body composition and body circumference. To evaluate the correlation between BMD and body composition, bone density and body weight, body mass index(BMI), lean body mass, muscle mass, fat mass and body fat mass were compared. The results of this study, weight was considered the strong correlation with BMD than the height and BMI seems to be greater significance rather than the lumbar spine and femur BMD. In addition, the relationship between body composition and BMD, lean body mass, muscle mass, body fat mass were the most relevant factors and BMD. The relationship between BMD and body circumference that have been difficult because of not enough previous studies but somewhat the study showed that association.

A Study on Impurities Measurement and Physical Properties of Semiconductive Shield at Power Cable (전력케이블에서 반도전 재료층의 불순물 측정 및 물성에 관한 연구)

  • 이경용;양종석;최용성;박대희
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.9
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    • pp.455-458
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    • 2004
  • In this paper, we investigated impurities content and physical properties showing by changing the content of carbon black that is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens was measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer), and density of specimens were measured by density meter And then specific heat (Cp) was measured by DSC (Differential Scanning Calorimetry). A ranges of measurement temperature were from $0^{\circ}[C]$ to $200^{\circ}[C]$, and heating temperature was $4^{\circ}[C/min]$. Impurities content was highly measured according to increasing the content of carbon black from this experimental result, also density was increased according to these properties. Especially impurities content values of the Al and A2 of existing resins were measured more than 4000[ppm]. Specific heat from the DSC results was decreased according to increasing the content of carbon black. Because ionic impurities of carbon black having Fe, Co, Mn, Al and Zn are rapidly passed kinetic energy increasing the number of times breaking during the unit time with the near particles according to increasing vibration of particles by the applied heat energy.

Physical and Chemical Properties of Cornmeal Extrudates by Addition of Defatted Soy Flour and Squid (옥수수가루, 탈지 콩가루 및 오징어를 이용한 스낵제품의 물리화학적 특성연구)

  • 정복미;김은실;이기춘
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.2
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    • pp.292-298
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    • 2001
  • This study was conducted to investigate physicochemical properties of extrudates combining 4 levels of squid (0, 3, 5 and 7%) with 3 levels of defatted soy flour (0, 5, and 10%). Blends were adjusted to moisture content of 27% and then extruded in a single-screw laboratory extruder at 170rpm screw speed and 16$0^{\circ}C$ barrel temperature. The extruded materials were dried at 6$0^{\circ}C$ for 8hr to a moisture content of 3~4% and refrigerated at 4$^{\circ}C$ for 12 hour before examination for textural properties, expansion ratio, bulk density, shear force and Hunter color. Expansion ratio of extrudates decreased as squid content increased whereas bulk density and shear force increased. Expansion ratio of extrudates was not significantly different by defatted soyflour level. Bulk density of products decreased as defatted soyflour content increased but shear force of products increased as defatted soyflour content increased. In scores of sensory hedonic evaluation of snacks, appearance, flavor, texture and overall acceptability values had lowered as squid level increased. Therefore, according to materials contents on extrudates increased, nutritional contents of this products increased and also shear force and bulk density in physical properties increased whereas expansion ratio decreased.

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Effects of Exercise on Bone Mineral Density and Bone Mineral Content in Postmenopausal Women

  • Choi Mi-Ja
    • Journal of Community Nutrition
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    • v.7 no.2
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    • pp.93-99
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    • 2005
  • This study investigated associations between exercise habit and bone mineral density (BMD) and bone mineral content (BMC) in postmenopausal women. The BMD and BMC of the spinal skeleton was measured by dual energy x-ray absorptiometry. Exercise and energy expenditure of physical activity were estimated by questionnaire. For exercise activities, subjects were asked to identify all exercises they have participated in. The subjects were further asked to estimate the number of years of participation, the number of weeks per year, the number of times per week, and the number of hours per time. Subjects were then categorized into exercise (more than 3 times/wk, more than 30min per session exercise (n = 47) and nonexercise group (n = 72). Results indicated that there were no significant differences in BMD and BMC when comparisons were made between subjects in exercise habit, a general exercise group and a nonexercise control group. However, when exercise subjects were divided into weight-bearing and nonweight-bearing groups, significant differences were found. These results suggest that weight-bearing exercise positively influences bone mineral density and bone mineral content in postmenopausal women. Sedentary women should be encouraged to adopt a weight-bearing exercise to maintain the health of their skeletons. Exercise interventions are practical and feasible for healthy women and should be encouraged at the earliest possible age. Our findings lend support to recommendations for physical activity and weight-bearing exercise as a means of osteoporosis prevention.

Strength Characteristics and their Behaviours of Marine Silty Sands (실트질 해사의 역학적 특성 및 거동에 관한 연구)

  • 장병욱;송창섭;우철웅
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.36 no.3
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    • pp.74-83
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    • 1994
  • A series of isotropic consolidation tests, undrained and drained triaxial compression tests was carried out to investigate the physical characteristics and behaviours of marine silty sands collected from the western coast of Korea. This study also included a theoretical development of the constitutive equation to evaluate stress-strain relationship and volume change of silty sands. The results and main conclusions of the study are summarized as follows; 1. Isotropic compression and swelling index are linearly decreased with an increase in relative density. 2. Both undrained shear strengh and elastic modulus are increased with an increase in relative density and confining pressure. 3. Internal friction angles obtained from drained and undrained compression tests of the soils are proportional to relative density. 4. The phenomenon of dilatancy of each sample is less profound when confining stress is increased but more profound when relative density is increased. 5. The slope of critical state lines is 1.78 for Saemangum, 1.70 for Siewha and 1.26 for Sukmoon sands. 6. In this study, Drucker-Praper type criterion is used and hardening function of Cap model is modified by hyperbolic fuction. This will improve a lack of physical meaning of hardening parameters in conventional Cap model. 7. A newly developed constitutive equation to the forementioned silty sands and checked its applicability. This is in good agreement with the measured data.

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Effect of Percentage of Resin Impregnation on the Preparation of High Density Woodceramics and the Physical Properties (수지함침율이 고밀도 우드세라믹 제조와 물성에 미치는 영향)

  • Oh, Seung Won;Jeon, Soon Sick
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.3
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    • pp.39-46
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    • 2008
  • Repeated impregnation and carbonization processes were performed to prepare high-density woodceramics using a sawdust board. The physical properties were investigated to confirm morphological and structural changes of one-time and two-time phenolic resin-treated and carbonized woodceramics. As comparing between one-time and two-time carbonized woodceramics, the weight and the density of the two-time carbonized woodceramics decreased with an increase of the amount of impregnated phenolic resin. In addition, when the amount of impregnated phenolic resin was about 40% in these woodceramics, the two-time carbonized woodceramics showed higher weight (23.8%) and density (30.0%) than the one-time treatment.

The Effect of the Elastic Band for Resistance Exercise Program on ADL and Bone Mineral Density in Arthritis Patients at Home (탄성저항 운동프로그램이 재가관절염환자의 일상생활동작과 골밀도에 미치는 효과)

  • Lee, Sang-Sook;Sohn, Ae-Ree;Chun, Sung-Soo;Lee, Wan-Hee;Kim, Seong-Yeol
    • Journal of muscle and joint health
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    • v.15 no.1
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    • pp.88-95
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    • 2008
  • Purpose: This study was to evaluate and compare the effectiveness of the Resistance Exercise Program on pain, stiffness, ADL and bone mineral density in Arthritis Patients at home. Methods: Forty-two patients participated in this study and they were divided randomly into two groups (exercise and control group). Two subjects dropped during the study period. The exercise group had a structured training which was 50 minutes in duration, five times per week for a period of 16 weeks and the control group without any scheduled treatment. Data were gathered for 16 weeks (May 21, 2007- September 10, 2007) and were analyzed by using SPSS Win 12.0. Results: The pain, stiffness, ADL, balance and bone mineral density in the exercise group were improved significantly after the Resistance Exercise Program. However, a significant improvement on the above mentioned variables was not observed in the control group.

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A study on physical properties of matt georgette knitted fabrics(I) - on the dimensional characteristics - (Matt georagette 평편포의 물성에 관한 연구(I) - 치수특성에 관하여 -)

  • Choi, Jae-Woo;Jun, Byung-Ik
    • Journal of the Korean Society of Industry Convergence
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    • v.3 no.4
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    • pp.337-343
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    • 2000
  • Physical properties of matt georgette knitted fabrics, which has been developed recently, were investigated to provide fundamental information for the textile industry. Dimensional characteristics were examined with three different loop lengths, where the plain knitted fabrics were knitted with cotton yam and polyester yarn. The matt georgette plain knitted stitch was fully relaxed after wet relaxation treatment at $130^{\circ}C$ for 30minutes and subsequent tumble dry treatment at $70^{\circ}C$ for 90minutes. As the treatment temperature of wet relaxation became higher and the loop length did shorter, all of stitch density, course density and wale density were increased with 31 of $K_1$ 8.3 of $K_2$ and 3.8 of $K_3$. Also, The higher value of $K_4$ could be obtain with shorter loop length. When the loop length became longer, the $K_4$ value was varied in a wide range with the treatment of wet relaxation and subsequent tumble dry.

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Assessment of Subsoil Compaction by Soil Texture on Field Scale

  • Cho, Hee-Rae;Jung, Kang-Ho;Zhang, Yong-Seon;Han, Kyung-Hwa
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.6
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    • pp.628-633
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    • 2015
  • It is necessary to assess soil physical properties and crop growth treated by compaction to establish the soil management standard. This study evaluated the bulk density, strength and crop growth after subsoil compaction for sandy loam and loam on the field in Suwon, Korea. The treatments were compaction and deep tillage. Sandy loam and loam were classified to coarse soil and fine soil, respectively, depending on clay contents. In coarse soil, bulk density of compacted plot was 8~17% greater than control and deep tilled plot. The root growth was worse in compacted plot compared with control. In fine soil, plow pan was not observed in deep tilled plot with 5~19% smaller bulk density than compacted plot and control. Deep tillage improved the crop growth. The soil physical properties by compaction were dependent on clay content and crop growth limit depended on the traffic driving.