• Title/Summary/Keyword: tear properties

Search Result 241, Processing Time 0.02 seconds

The Effect of Eccentric Strengthening Exercise on Athletes after Shoulder Rotator Cuff Tear (운동선수들의 견관절 회전근 손상 이후 등속성 측정을 통한 원심성 근력운동의 효과)

  • Kim, Jwa-Jun;Kim, Dae-Kyeong;Ha, Kyung-Jin
    • PNF and Movement
    • /
    • v.12 no.1
    • /
    • pp.33-37
    • /
    • 2014
  • Purpose: In this research, the properties of the shoulder joint were measured through eccentric resistive exercise with the patients who have rotator cuff tear of shoulder joints as the targets. Methods: 23 patients who have pain due to the rupture of rotator cuff on shoulder joints were selected and divided into Exercise group (12) and Control group (11). Two groups executed exercise for 30 minutes 3 days a week. Exercise group had executed eccentric resistive exercise, and the Control group executed Complex exercise. Results: In external rotation $180^{\circ}/s$, $240^{\circ}/s$, the Exercise group showed to be an average of 8% higher than the Control group. For Internal rotation $90^{\circ}/s$, $180^{\circ}/s$, $240^{\circ}/s$ the Exercise group showed to be an average of 30% higher that the Control group. Conclusion: To lessen the rupture of rotator cuff on shoulder joints, muscles strengthening is very important across various methods of eccentric exercise programs which are external/internal rotators of the shoulder joint needed for throwing. This is effective in preventing injury and improving rotation.

Effect of Recycling on the Papermaking Properties of Wood Pulp Fibers (펄프섬유(纖維)의 제지특성(製紙特性)에 미치는 회수처리(回收處理)의 영향(影響))

  • Kim, Hyoung-Jin;Jo, Byoung-Muk
    • Journal of the Korean Wood Science and Technology
    • /
    • v.21 no.1
    • /
    • pp.21-38
    • /
    • 1993
  • In order to investigate the influence of recycling, a laboratory method simulating the papermaking process was used for assessing the effects of recycling on fiber properties. Sw-BKP, Hw-BKP and BGP were disintegrated and beaten to about 42$^{\circ}$SR-44$^{\circ}$SR by a valley beater. After beating, these pulps were dewatered by centrifuge and dried at 90$^{\circ}C$ for 72hrs. This recycling process(sequence of wetting, defiberating, dewatering and drying) was repeated seven times. Physical, mechanical and optical properties of recycled pulps were evaluated by TAPPI Standards. Morphological changes occurred through recycling process was observed by SEM. Sheet density decreased with recycling. The largest drop in density occurred during the first recycling. The porosity values decreased with recycling. Mechanical properties such as tensile, burst strength and folding endurance, decreased with recycling. However tear strength of Sw-BKP and mixtured pulp increased at the first recycling. Optical properties such as brightness, opacity and light scattering coefficient, increased with recycling. However, brightness of mixtured pulp gradually decreased with recycling. Fibrillated outer layer of the fiber was gradually removed from the surface with recycling. As a result of recycling, crinkles on the fiber surface were found to be more folded.

  • PDF

Physical and Strength Properties of Frankincense Resin Treatment Paper (유향수지 처리지의 물리 및 강도적 특성)

  • Kim, Jong-Min;Yoon, Seung-Lak;Jo, Jong-Soo
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.46 no.6
    • /
    • pp.26-33
    • /
    • 2014
  • Frankincense resin was applied to Hanji to improve its physical properties. The resin-treated paper showed the increasement of physical properties such as weight, thickness, and density. The highest increasement in weight and density of resin-treated paper were found at 30% treatment concentrations and the largest values of density were $41g/m^2$ Hanji. With the increasement of concentration, the brightness was decreased and transparency was improved. Of the mechanical properties of the paper, the tensile index and burst index showed the improved values. The tear index, however, was decreased. The frankincense resin showed the highest result in the tensile index of resin-treated paper and the basis weight of $41g/m^2$ Hanji. The air resistance of the resin-treated paper got improved with the increase of the concentration and $105g/m^2$ Hanji showed the highest values. The highest improvement in air resistance may make the resin-treated Hanji possible to use for semipermeable materials.

EFFECT OF MAGNESIUM OXIDE CONTENTS ON THE PROPERTIES OF EXPERIMENTAL ALGINATES (산화마그네슘 함량이 실험적 알지네이트 인상재의 특성에 미치는 영향)

  • Bae Ill-Hwan;Woo Yi-Hyung;Choi Dae-Gyun
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.41 no.5
    • /
    • pp.551-564
    • /
    • 2003
  • Statement of problem : Magnesium oxide may increase pH of alginate, and supply magnesium ions to the polymerization reaction of alginate. Purpose : This study was designed to evaluate the influence of incorporation of magnesium oxide to alginate composition. Material and Method : Seven kinds of experimental alginates were prepared and used for the experiments. Components with unchanging concentrations were sodium alginate 15%, calcium sulfate 14%, sodium phosphate 2%, and zinc fluoride 3%. Contents of magnesium oxide were varied as 0%, 1%, 2%, 3%, 4%, 5%, 6%. Diatomaceous earth were added to each experimental groups as balance to be 100%. Control group was a MgO 0% group. Working time, setting time, elastic recovery strain in compression, compressive strength and tear resistance were measured were measured. Sample size for each groups were 10. Arithmetic means were used as each groups representative values. Regression test between MgO contents and results, Duncan's multiple range test, and One-way ANOVA test were done between groups at level of 0.05. Results : 1 Magnesium oxide made the working time and setting time as longer(p<0.0001). 2 Magnesium oxide did not alter the elastic recovery(p>0.05). 3. Magnesium oxide contents between 2% and 4% exhibited the lowest strain in compression on alginates(p<0.0001). 4. Magnesium oxide made the compressive strength and the tear resistance stronger(p<0.0001). Conclusion : These results mean that setting time of alginate maybe controlled and that mechanical properties maybe improved by the incorporation of magnesium oxide into alginate, without any reduction of elasticity.

Influence of Inorganic Filler on Properties of EPDM Compounds (무기 충전제가 EPDM 배합물의 특성에 미치는 영향)

  • Choi, Sung-Seen;Kim, Ok-Bae
    • Elastomers and Composites
    • /
    • v.46 no.2
    • /
    • pp.138-143
    • /
    • 2011
  • EPDM compounds and vulcanizates containing inorganic filler such as talc, calcium carbonate, or clay as well as carbon black were prepared, and the influence of inorganic filler on properties of the EPDM compounds and vulcanizates were investigated. The bound rubber contents did not significantly increase even though the inorganic filler was added. There were big aggregates in the EPDM samples with high loading inorganic filler. By adding the inorganic filler, the cure times tended to increase and the delta torque decreased. The modulus were on the whole decreased, whereas the elongation at break, tensile strength, and tear strength were increased by adding the inorganic filler. The decreased modulus and increased elongation at break can be explained with the decreased delta torque, the increases of tensile strength and tear strength can be explained with the increased elongation at break. By adding the inorganic filler, level of reinforcing in the EPDM compounds did not increase and the crosslink density decreased.

The Effect of Offset Ink Formulation on Deinking of Old Newspaper (옵셋잉크 조성분이 신문고지 탈묵에 미치는 영향)

  • Kim, Yong-Sek;Paik, Ki-Hyon
    • Applied Chemistry for Engineering
    • /
    • v.7 no.4
    • /
    • pp.787-793
    • /
    • 1996
  • In this paper, to investigate the effect of the offset ink formulation on deinking of Korean old newspaper, the samples printed with five different types of offset ink were aged naturally for 10, 30, 90, 180 days, and then yield, brightness, fiber length, physical properties(tensile, tear, burst index) were evaluated according to aging time. As the aging time increased, the yield and brightness of respective samples decreased. Particially, as the addition amounts of linseed oil increased, those of samples decreased. Therefore, linseed oil is thought to reduce the deinkability of ink. Also, containing rosin-modified phenolic resin and gilsonite seem to reduce brightness of samples according aging time. In physical properties, tensile index and burst index were roughly decreased, but tear index was increased according to aging time. However, the three indexes of the sample containing only linseed oil as the vehicle component were considerably reduced in comparison with those of other samples, as once crosslinked a strong bond between the ink and fibers was produced and made it difficult to defibrate in producing sheets.

  • PDF

Professional climbers' demand for movement functionality in pants (전문가용 클라이밍 팬츠의 활동 기능성 수요특성 연구)

  • Jung, Semi;Chun, Jongsuk
    • The Research Journal of the Costume Culture
    • /
    • v.21 no.2
    • /
    • pp.261-271
    • /
    • 2013
  • This study aimed to identify professional climbers'demand for movement functionality in pants worn for rock climbing and ice climbing. Data were collected through in-depth interviews with 12 professional climbers using a semi-constructed questionnaire. The respondents were instructor-level experts whose climbing ability ranged from 5.9 to 5.14 on the Yosemite Decimal System rating scale. The research findings were as follows. Experts wore different climbing pants depending on the type of climbing. For example, they mostly wore high-stretch, second layer pants for rock climbing, while layering first layer, second layer, and third layer pants for ice climbing. There were gender differences regarding the parts of the body in which climbers reported the most discomfort when wearing climbing pants; male climbers most commonly responded 'knees', 'inner thighs' and 'hips' while their female counterparts most commonly responded 'inner thighs', 'exposed back and waist' and 'hips' in that order. Differences were found between rock climbing and ice climbing in terms of wear and tear on pants, preferred fabric properties, and length of pants. Wear and tear was found mainly on the hips and knees of rock climbing pants and on the inner lower hem of ice climbing pants. Listed in the order of preference, the most preferred fabric properties were elasticity, light weight, and durability for rock climbing pants and elasticity, insulation, and protection against water and wind for ice climbing pants. Regarding the length of rock climbing pants, respondents preferred ankle-length pants and cropped pants that did not cover the feet. For ice climbing pants, respondents favored heel-length pants that prevented pieces of ice from entering the clothing. Men showed a high level of preference for ergonomically cut climbing pants. Respondents said the waistband on climbing pants should be simplified so as not to adversely affect climbing maneuvers.

A Study of the Effect of Degree of Cure on the Physical Properties of Rubber Compounds (가교정도에 따른 고무복합체의 물리적 특성에 관한 연구)

  • Kim, Hyeon-Jae;Kaang, Shin-Young;Nah, Chang-Woon
    • Elastomers and Composites
    • /
    • v.33 no.4
    • /
    • pp.281-289
    • /
    • 1998
  • Tensile properties including Young's modulus and tear strength were measured for four different rubber compounds; natural rubber(NR), styrene-butadiene copolymer(SBR), ethylene-propylene diene monomer (EPDM), and brominated isobutylene-p-methyl-styrene copolymer(BIMS) as a function of temperature and degree of cure. To see the effect of over cure, a measurement was made of the tensile strength and swelling behavior of the over-cured rubber compounds. Young's modulus, E, was found to have linear dependency on the degree of cure for all rubber compounds. EPDM and BIMS showed the highest and lowest slopes, respectively. The slope of NR and SBR lay between EPDM and BIMS. Tear strength, Gc, decreased in the order of NR>BIMS>SBR>EPDM. As the cure time was extended the degree of cure of NR and SBR decreased, while that of BIMS increased. EPDM showed little change in the degree of cure.

  • PDF

The Effects of the Cutting Length of Paper Mulberry Bast Fiber on Pulping and Hanji Properties(I) - White bast of Korea grown paper mulberry - (닥나무 인피섬유의 절단장이 펄프화 및 한지의 물성에 미치는 영향(제1보) - 국산 닥 백피의 특성 -)

  • Lim, Gang-Hyouk;Choi, Tae-Ho
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.40 no.2
    • /
    • pp.57-64
    • /
    • 2008
  • In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

Changes of Handsheet Fracture Toughness by Wood and Cotton Fibers Mixing (목재섬유와 면섬유의 혼합에 따른 수초지의 파괴인성 변화)

  • Kim, Jeong-Jung;Jang, Dong-Uk;Yoon, Sang-Gu;Shin, Hyeon-Sik;Park, Jong-Moon
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.46 no.3
    • /
    • pp.81-87
    • /
    • 2014
  • Conditions of paper manufacturing process should be changed depending on the end use and paper properties. Most of the case, mixed pulps with long softwood fibers and short hardwood fibers are used to achieve proper qualities of product with reasonable production cost. For specialty paper manufacture the wood pulp and cotton linter pulp are usually mixed together. The objectives of this study is to analyze physical, mechanical and fracture mechanical properties of paper depending on SwBKP, HwBKP and cotton linter pulp(CLP) mixing. When the mixing ratio of SwBKP was increased, strength properties, such as tensile, tear, and folding endurance, were also increased. When the mixing ratio of SwBKP and HwBKP was increased, stress concentration index was decreased and fracture toughness was increased.