• Title/Summary/Keyword: hand strength

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Effect of Additive Ball Clay on Physical Properties of Porous Ceramic (볼 클레이 첨가에 따른 세라믹 다공체의 물리적 특성변화)

  • Kang, Young-Sung;Kim, Sang-Sik
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.2
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    • pp.109-112
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    • 2014
  • A porous ceramic which has fine porosity and small specific gravity is made with Cenosphere and Ball Clay under condition of $1,250^{\circ}C$ in calcination temperature and 30 minutes of calcination time. The average size of porous ceramic was about $2.5{\times}10^{-5}$ m and pores are well developed. The void-fraction of porous ceramic was 67.1% under the input of Cenosphere and Ball clay with the weight ratio of 100 to 5. However, as weight ratio of Ball Clay increased to 20, 40, 100, the void fraction decreased to 58.4, 56.7, 47% respectively. When the weight ratio of Cenosphere and Ball Clay was 100 to 100, the apparent density of porous ceramic was $1.04g/cm^3$. which is twice the density when the weight ratio of Ball Clay was 5. On the other hand, absorption rate decreased by at least 100%. In condition of weight ratio of Cenosphere and Ball Clay was 100 to 100, compressive strength of porous ceramic was 30 (MPa), improve by about 76% or more when the weight ratio of Ball Clay was 5.

Effects of Preflocculated Filler Flocs and Nano-sized Coating Binder on Fold Cracking of Coated Paper (충전물 선응집체 크기와 나노 바인더에 의한 도공지의 접힘터짐 변화)

  • Im, Wanhee;Seo, Dongil;Oh, Kyudeok;Jeong, Young Bin;Youn, Hye Jung;Lee, Hak Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.5
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    • pp.91-97
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    • 2015
  • Papermakers wish to increase the filler content of printing and writing grades because it allows saving in production cost through fiber replacement and improving the formation, and optical and printing properties of the paper. However, high filler loading in the base paper has negative side effects. It reduces the mechanical properties of paper and induces cracking at the fold after coating process. Fold cracking is one of the most frequent quality complaints for magazines, high quality books, etc. Two approaches were examined as methods to reduce fold cracking. One approach was to use preflocculated fillers, which was expected to reduce the fold cracking because it would decrease the interfiber bonding. The other approach was to use a new coating binder that gives greater binding power and thereby provides an opportunity of reducing the fold cracking of coated paper. When filler preflocculation was employed in producing the base paper, fold cracking becomes more severe than conventional filler loading condition. On the other hand, use of nano sized binder in coating improved the tensile properties of the coating layer and thereby decreased the crack area. It was shown that tensile properties of coating layer played an important role in fold cracking of coating.

Studies on the application of bacterial sericinase -(Part II) Appling on the unwinding for mulberry cocoon- (세균성(細菌性) Sericin 분해효소(分解酵素)의 이용(利用)에 관(關)한 연구(硏究) -(제II보(第II報)) Sericinase에 의(依)한 가잠견(家蠶繭)의 해서(解舒)에 관(對)하여-)

  • Seu, Jung-Hwn;Song, Bang-Ho;Han, Yung-Gu;Kho, Yung-Hee
    • Applied Biological Chemistry
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    • v.13 no.1
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    • pp.87-92
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    • 1970
  • Sericin hydrolyzing enzyme, produced by the selected bacteria, S4-1-1, was studied and following properties were obtained. 1. The activity of this bacterial sericinase was not decreased for 30 days of storage at $5^{\circ}C$. But at $20^{\circ}C$, for 30 hrs. was the maximum period to keep the initial activity of this enzyme. 2. This bacterial enzyme gave only sericinase activity but never indicated fibroin hydrolyzing activity. 3. The chelating reagent of EDTA and Ag or Hg ions were classified as strung inhibitors but Cu and Cd ions were indicated as moderate inhibitors to this enzyme action. 4. This enzyme was not inhibited by the surface active agent, Peretex-N, but strongly activated by this agent at low concentration. In the other hand, by the application of this enzyme to the unwinding works on the mulberry cocoon, the following results were also obtained. 1. On the weight and length, nonbreaking Length, size, colour and unwinding ratio of have, the enzyme appling method was superior to generally used cooking method. 2. The tested results of strength and elongation, bouchon, haririness loops, neatness and evenness of have were also indicated spuerior properties.

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Behavior of Hybrid Stud under Compressive Load (복합스터드의 압축 좌굴 거동)

  • Lee, Sang Sup;Bae, Kyu Woong
    • Journal of Korean Society of Steel Construction
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    • v.16 no.5 s.72
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    • pp.609-619
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    • 2004
  • An investigation was conducted on the activities around Europe in order to solve the problem of the thermal bridging of steel studs, which had caused a significant disadvantage. This study included the following: diminishing the contact area between the studs and the sheathing, lengthening the heat transfer route, replacing the steel web with a less conductive material, and placing foam insulation in locations where the thermal shorts are most critical. Although energy efficiency is usually the focus of such foreign cases because their stud application is mostly limited to low-rise residential buildings, both structural and thermal performance are taken into consideration in this study because these target middle-story buildings. A hybrid stud composed of steel and polymer was also developed. This hybrid stud, which is 150 SL in size, is made of a galvanized steel sheet (SGC58) and a glass fiber reinforced polymer (GFRP) withepoxy bonding. A total of 32 specimens were manufactured. Its parameters comprise two types of connection detail,s: the thickness of steel (1.0mm and 1.2mm) and of the GFRP (4mm-4ply and 6mm-6ply), and the ratio of the length to the depth (L/D = 3, 6, 9, 12). Steel stud specimens with the same conditions were compared to the hybrid stud. The test revealed that in the case of the steel specimen with a thickness of 1.0mm, the maximum load of hybrid studs increased an average of 1.62 times comparedto that of the steel stud. In the case of the steel specimen with a thickness of 1.2mm, on the other hand, the average increase was 1.46times. All specimens showed full composite action until the collapse.

Survey on the Use and Perception of Health Functional Foods and Herbal Medicine for Children in Local Day Care Center - Focus on Wonju and Chungju Region - (어린이집 아동의 건강기능식품 이용실태와 한약이용에 대한 인식 - 원주와 충주의 일부 어린이집을 대상으로 -)

  • Sung, Hyun-Kyung;Min, Deul-Le;Park, Su-Jung;Sung, Angela Dongmin;Lee, Sundong;Park, Haemo
    • Journal of Society of Preventive Korean Medicine
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    • v.21 no.2
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    • pp.117-126
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    • 2017
  • Objectives : The use of health functional foods is gradually increasing. On the other hand, the use of the Korean herbal medicine is gradually decreasing. Especially children are known to have a high percentage of taking a health functional food. This study was designed to compare the use of health functional food with the reason for taking the Korean herbal medicine. Methods : The participants were 453 parents who have kids age between 3 to 6 years old from day care center in Wonju and Chungju. The questionnaire consisted of 17 questions and the survey was conducted by self-entry method. This study analyzed 374 participants' questionnaires who agreed to the survey. Results : The percentages of children's health functional food intake experience were 82.9% and they usually bought products which contain lactic acid bacteria(55.6%). The reason for consuming health functional food was to strengthen the immune system and enhance the physical strength. Most of the participants purchased health functional food from pharmacy through inaccurate information such as the internet. The percentages of children's health functional food preference were 58.5% because it is easy to take. The percentages of children's herbal medicine preference were 41.7%. There are inconveniences of taking herbal medicine because of taste and smell(68.8%). Conclusions : Therefore, it is necessary to change the formulation of the herbal medicine and increase convenience for use of the herbal medicine to preschooler(3-6 years old). In additionary, it is necessary to supply accurate and up to date information of herbal medicine taking.

Interfacial Reaction and Joint Strength of the Sn-58Bi Solder Paste with ENIG Surface Finished Substrate (Sn-58Bi 솔더 페이스트와 ENIG 표면 처리된 기판 접합부의 계면 반응 및 접합강도)

  • Shin, Hyun-Pil;Ahn, Byung-Wook;Ahn, Jee-Hyuk;Lee, Jong-Gun;Kim, Kwang-Seok;Kim, Duk-Hyun;Jung, Seung-Boo
    • Journal of Welding and Joining
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    • v.30 no.5
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    • pp.64-69
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    • 2012
  • Sn-Bi eutectic alloy has been widely used as one of the key solder materials for step soldering at low temperature. The Sn-58Bi solder paste containing chloride flux was adopted to compare with that using the chloride-free flux. The paste was applied on the electroless nickel-immersion gold (ENIG) surface finish by stencil printing, and the reflow process was then performed at $170^{\circ}C$ for 10 min. After reflow, the solder joints were aged at $125^{\circ}C$ for 100, 200, 300, 500 and 1000 h in an oven. The interfacial microstructures were obtained by using scanning electron microscopy (SEM), and the composition of intermetallic compounds (IMCs) was analyzed using energy dispersive spectrometer (EDS). Two different IMC layers, consisting of $Ni_3Sn_4$ and relatively very thin Sn-Bi-Ni-Au were formed at the solder/surface finish interface, and their thickness increased with increasing aging time. The wettability of solder joints was investigated by wetting balance test. The mechanical property of each aging solder joint was evaluated by the ball shear test in accordance with JEDEC standard (JESD22-B117A). The results show that the highest shear force was measured when the aging time was 100 h, and the fracture mode changed from ductile fracture to brittle fracture with increasing aging time. On the other hand, the chloride flux in the solder paste did not affect the shear force and fracture mode of the solder joints.

Effects of Transverse Reinforcement on Headed Bars with Large Diameter at Cut-off Points (컷오프 구간에 정착된 대구경 확대머리철근에 대한 횡보강근의 효과)

  • Jung, Hyung-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.5
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    • pp.82-90
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    • 2018
  • The nuclear structures are composed of large diameter bars over No.36. If the hooked bars are used for anchorage of large diameter bars, too long length of the tail extension of the hook plus bend create congestion and make an element difficult to construct. To address those problems, headed bars were developed. Provisions of ACI 318-08 specify the development length of headed bars and ignore the effect of transverse reinforcement based on the background researches. However, if headed bars are used at the cut-off or lap splice, longitudinal reinforcements, which are deformed in flexural members, induce tensile stress in cover concrete and increase the tensile force in the transverse reinforcement. The object of this research is to evaluate the effects of transverse reinforcement on the anchorage capacity of headed bar so anchorage test with variable of transverse rebar spacing was conducted. Specimens, which can consider the behavior at the cut-off, were tested. Test results show that failure of specimen without transverse reinforcement was sudden and brittle with concrete cover lifted and developed stress of headed bars was less than half of yield strength of headed bars. On the other hand, in the specimen with transverse reinforcement, transverse rebar directly resist the load of free-end so capacity of specimens highly increased.

A Study of the Personal Ornaments and Make-up of Maroccan (모로코인(人)의 장신구(裝身具)와 화장(化粧)에 관(關)한 연구(硏究))

  • Lee, Soon-Hong
    • Journal of Fashion Business
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    • v.5 no.2
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    • pp.15-34
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    • 2001
  • Ornaments are accessories for the decoration of the body or dress. They aren't unavoidably required one, but serve to make one's dress perfect as decorative industrial art objects. In Morocco, ornaments were initially used as a sign of social position or the class or an incantatory symbol. In effect, they were originally employed to adjust one's dress, not just for decoration, and they were of use for household economy. Gold, silver and handcraft available for exchange were a means of increasing one's property and an indication of social standing and wealth. In particular, the dress and jewelry of a bride was a measure of her family's wealth, regarded as a symbol of her chastity and value. The ornaments symbolically back up people's faith in supernatural power, and their real value is based on implicit form or way of decoration, not the external shape. Specifically, there is a tendency to use the form of animal as a protector, not one to frighten people. In the artistic tradition of Morocco, fish pattern stands for water and rain, and eagle and bird are considered to be related to fate. Scorpion and lizard are depicted as an inquirer of sun, and snake is a symbol of abundance and sexual instinct, being viewed to have an ability to cure disease. Turtle pattern is a symbol of saint because it protects one from the evil. The ornaments are made of gold, silver, amber, clam, garnet, glass, nielle, enamel, glaze, coral or tree, and symbolic patterns are used, including hand(a symbol of five numerals), turtle, lizard, scorpion, eye, triangle, bird and eggs. They are very big and diverse, being categorized into ornaments for the head or the chest, neckless, fibula, earring, bracelet and ring. For Moroccans, make-up is a sort of instinctive behavior to meet aesthetic and sexual desire. They also wear make-up for practical purpose of protection, intentionally inflict a wound on the skin for ceremonial or religious purpose, paint the skin with pigment, or have the part of the body tattooed for incantatory purpose. All this actions are regarded as make-up. The raw material of cosmetics is aker, a vegetable dye. They get the lips or cheeks turn red and paint eyebrows with yellow saffran powder to have a bad devil lose its strength. Tattooing is mainly done by women and viewed as a sign of their value or social organization they belong to. Sometimes that is used to represent a woman's being old enough to marry or getting married already or the frequency of marriage. Besides, tattoo is believed to prevent or remedy loose bowels or cough, depending on its location or pattern, and they often change tattoo according to the change of beauty art.

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Shear Behavior of Sands Depending on Shear Box Type in Direct Shear Test (직접전단실험시 전단상자의 종류에 따른 모래시료의 전단거동)

  • Hong, Young-Ho;Byun, Yong-Hoon;Chae, Jong-Gil;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.31 no.3
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    • pp.51-62
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    • 2015
  • Shear behavior obtained by direct shear tests is dependent on shear box and boundary condition. The objective of this study is to analyze problems of conventional direct shear test (type-A) and provide the reliable results by developing type-C direct shear apparatus. Experimental tests are carried out for Ulleung sand by using type-A and -C direct shear devices. The soil specimens, which are prepared at the relative density of 60%, and are applied to vertical confining stresses of 50, 100, 200, 300, and 400 kPa, are sheared at a constant shear strain rate of 0.5 mm/min. By comparing the results obtained by type-A and -C direct shear apparatus under constant normal load (CNL) condition, the performance of new one is verified. In addition, two constrained conditions including constant normal load (CNL) and constant pressure (CP) are applied to type-C one. Experimental results show that type-A direct shear apparatus has some problems such as rotating of loading plate and upper shear box, and the frictional forces between soil and inner wall of upper shear box. Thus, the shear strengths obtained by type-A device are overestimated or underestimated depending on shear box and boundary condition. On the other hand, type-C device produces clear and consistent test results regardless of constrained conditions. This study represents that type-C direct shear apparatus not only can solve the problems of type-A direct shear apparatus but provide the reliable results.

A Study on Crushing and Engineering Characteristics Caused by Compaction of Recycled Aggregates (다짐으로 인한 순환골재의 파쇄 및 공학적 특성에 관한 연구)

  • Park, Sung-Sik;Chen, KeQiang;Lee, Young-Jae;Moon, Hong-Duk
    • Journal of the Korean Geotechnical Society
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    • v.33 no.12
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    • pp.35-44
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    • 2017
  • A large amount of recycled aggregates was produced and crushed from old buildings and pavements. In this study, when these aggregates are re-used in subbase or subgrade materials in near construction sites, their engineering characteristics caused by crushing are investigated in terms of permeability and shear strength. Three different sizes of aggregates (31.5-45.0 mm, 19.0-31.5 mm, 9.5-19.0 mm) and their mixtures, a total of 7 types of aggregates were used in compaction tests (modified D and B methods). After compaction tests, aggregates were sieved and analyzed with four different breakage factors ($B_{15}$, $C_c$, $B_{10}$, $B_r$). The D compaction method gave 2.0-8.0 times more crushable than B compaction method. The breakage factors for the largest size aggregate was 1.4-3.0 times higher than those of the smallest size aggregate. For aggregates with 5.6-9.5 mm sizes, the samples were prepared with $B_{15}$ of 1, 3, 10, 20, 30, 50, 60, and 70 for permeability and direct shear tests. As $B_{15}$ increased, the hydraulic conductivity decreased up to 1/22 for $B_{15}=50$. As $B_{15}$ increased from 1 to 50, the peak friction angle increased from $46.1^{\circ}$ to $54.5^{\circ}$. On the other hand, the friction angle decreased after $B_{15}=60$.