• Title/Summary/Keyword: Puncture resistance

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Resistance of Ceosynthetics Due to Puncture Loads : Resistance Forces-deformation (지오신세틱스의 천공(꿰뚫림) 저항성에 관한 연구 : 재료별 천공하중-변형관계)

  • 이광열;정진교;안용수
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.263-272
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    • 2003
  • Various types of geosynthetics have been manufactured and their applications are rapidly extended disregarding unreliable lifetime, chemical and biological persistence and puncture resistance. Puncture resistance of geosynthetics in earth structures and liner systems has been a critical issue to be improved. In this paper, comparative studies were made on a puncture resistance of various geosynthetics that were used to a liner system. Two types of puncture tools and rubles and gravels were used to generate punctures on geosynthetics. From the results it is shown that types of puncture tools affect puncture resistance of materials significantly and puncture forces were irregular depending upon puncture tools and materials.

Puncture and Cutting Resistance Characteristics of Shear Thickening Fluid Impregnated Kevlar Fabrics (전단농화유체가 함침된 Kevlar 직물의 방검 및 방침 특성)

  • Lee, Bok-Won;Kim, Il-Jin;Lee, Yeon-Gwan;Kim, Chun-Gon;Yoon, Byung-Il;Paik, Jong-Gyu
    • Composites Research
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    • v.21 no.5
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    • pp.23-30
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    • 2008
  • Stab threats using sharp edged or pointed Instruments could be easily encountered by police officers or soldiers. In this study, the shear thickening fluids (STF) was impregnated into Kevlar fabrics to improve the stab protection and the resistance of STF impregnated Kevlar fabrics was experimentally investigated. The puncture and cut resistance were tested using a drop test machine withspike and knife indenters fabricated based on the National Institute of Justice (NIJ) standard. The STF was filled with spherical $SiO_2$ particles having an average diameter of 100nm, 300nm, and 500nm. The effect of particle size on puncture and cut resistance of STF impregnated Kevlar fabrics was also investigated. The measured impact load histories showed that STF impregnation into fabric leads to withstand higher peak loads than that of neat fabrics under spike test. The test results showed that Kevlar impregnated with STF exhibit remarkable improvements in puncture resistance while it is slightly influential on the cut resistance. Specifically, particle size is the one of the dominant factors controlling fabric resistance to puncture under spike impact test.

Resistant Effects of Geosynthetics Against Puncture Loads as a Protective of HDPE (차수재(HDPE) 보호재로서 토목섬유의 천공(꿰뚫림)하중에 대한 저항효과)

  • 이광열;장삼식;구태곤
    • Journal of the Korean Geotechnical Society
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    • v.20 no.6
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    • pp.11-17
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    • 2004
  • This study focused on the protection effects of geosynthetics installed on HDPE to resist against puncture loads. The study was conducted by a model test with various types of puncture loads created by different shapes of tools. The puncture resistance of geosynthetics installed as a protective material on HDPE is varied depending on the sizes of geosynthetics and types of puncture loads. In this study, it was found that the protection effect far all kinds of geosynthetics when a truncated cylindrical shape of puncture tool is used is lower than others. Also, geocomposite has the most excellent protection effect against all types of puncture loads.

Inadvertent Dural Puncture during Epidural Block (경막외 차단시의 경막천자)

  • Kang, Keum-Ye;Min, Ki-Chul;Kim, Dong-Chan;Choe, Huhn
    • The Korean Journal of Pain
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    • v.1 no.2
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    • pp.203-206
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    • 1988
  • Evaluation of inadvertent dural puncture occuring among 308 epidural blocks done for the relief of pain from various conditions was performed. Dural puncture was suspected in 5 out of 308 epidural bloks. (1.6%) Aspiration of CSF was negative in 3 cases in which dural puncture was suspected only after developing spinal anesthesia. Of the 3 negative CSF aspirations, one case had a history of laminectomy. Adhesions of the adjacent tissues might result in the loss of flexibility and a decrease in potential epidural space which might cause dural tearing during injection and subarachoid injection of the local anesthetic followed by high spinal anesthesia. In another case, the needle tip was obstructed by tissue which led to negative aspiration of CSF and failure to feel loss of resistance. The second injection at the same site may cause subarachnoid injection of the local anesthetic through the previously perforated dura mater and in turn, lead to spinal anesthesia. In the last case, there was no reason to suspect dural puncture since the loss of resistance plus air rebound were definite and aspiration of CSF was negative, but dural puncture was suspected after the patient developed spinal anesthesia.

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Mechanical Tenacity Analysis of Moisture Barrier Bags for Semiconductor Packages

  • Kim, Keun-Soo;Kim, Tae-Seong;Min Yoo;Yoo, Hee-Yeoul
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.1
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    • pp.43-47
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    • 2004
  • We have been using Moisture Barrier Bags for dry packing of semiconductor packages to prevent moisture from absorbing during shipping. Moisture barrier bag material is required to be waterproof, vapor proof and offer superior ESD (Electro-static discharge) and EMI shielding. Also, the bag should be formed easily to the shape of products for vacuum packing while providing excellent puncture resistance and offer very low gas & moisture permeation. There are some problems like pinholes and punctured bags after sealing and before the surface mount process. This failure may easily result in package pop corn crack during board mounting. The bags should be developed to meet the requirements of excellent electrical and physical properties by means of optimization of their raw material composition and their thickness. This study investigates the performance of moisture barrier bags by characterization of their mechanical endurance, tensile strength and through thermal analysis. By this study, we arrived at a robust material composition (polyester/Aluminate) for better packing.

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Pneumocephalus Developed during Epidural Anesthesia for Combined Spinal-Epidural Anesthesia (척추경막외병용마취를 위한 경막외마취 중 발생한 기뇌증)

  • Kim, Youn Jin;Baik, Hee Jung;Kim, Jong Hak;Jun, Joo Hyun
    • The Korean Journal of Pain
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    • v.22 no.2
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    • pp.163-166
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    • 2009
  • The superiority of air versus saline for identifying the epidural space remains unestablished. Epidural anesthesia using a loss of resistance technique (LORT) with air is associated with increasing complications of dural puncture-induced headaches and neurological and hemodynamic changes. Here, we described a case of pneumocephalus with a large amount of air that was accompanied by severe headache and nuchal and chest pain occurring after epidural block using LORT with air for combined spinal-epidural anesthesia.

Comparison of Methods to Confirm the Cervical Epidural Space (경추 경막외강 확인법의 비교 연구)

  • Ok, Si Young;Chun, Hae Rim;Baek, Young Hee;Kim, Sang Ho;Kim, Soon Im;Kim, Sun Chong;Park, Wook;Song, Dan
    • The Korean Journal of Pain
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    • v.22 no.2
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    • pp.158-162
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    • 2009
  • Background: The loss of resistance (LOR) method is most commonly used to identify the epidural space. This method is thought to rely on the penetration of the ligamentum flavum. Unfortunately the exact morphology of the ligamentum flavum is variable at different vertebral levels. Especially, it has been pointed out that the lower cervical ligamentum flavum may be discontinuous in the midline in up to 50% of patients. Thus, the LOR method may be inaccurate to confirm the cervical epidural space. The aim of this study is to determine which method is the safest and most exact for confirming the cervical epidural space. Methods: 100 adult, chronic renal failure patients who were undergoing an arteriovenous bridge graft for hemodialysis at the upper arm under cervical epidural anesthesia were recruited for this study. During the cervical epidural puncture, we identified the cervical epidural space by subjectively feeling the resistance with using a finger just through the ligamentum flavum, and we also used the drip infusion method, the loss of resistance method using air, and the hanging drop method. By using 5 grades, we classified the extent of whether or not the techniques were effective. Results: Using the drip infusion method, we identify the epidural space in all the patients as +/++ grade. The catheter insertion method was also successful in identifying those epidural spaces over a ${\pm}$ grade. The pseudo LOR was over ${\pm}$ grade in 47 patients. Conclusions: The combined LOR/hanging drop with drip infusion method is useful for confirming the cervical epidural space.

Novel characterisation methods for Polymer Applications

  • Bailey, R.S.;McNicol, A.;Lambert, P.
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.142-143
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    • 2006
  • Combinatorial methods are being used increasingly to develop the next generation of polymers, coatings and adhesive formulations. Allied to this approach, a new genre of measurement and characterization methods are emerging. These characterization techniques are required to handle and take measurements from small samples. This has led to a number of uses for this technology which usefully fall between convention test specimen and micro- or nano-scale test methods. A versatile measurement platform will be presented which can offer useful indentation, puncture, compression, adhesion and scratch resistance data for a wide variety of material types and that continues to develop and evolve in capability.

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Studies on Resistance to anthracnose (Colletrichum dematium) in Pepper (고추의 탄저병(炭疽病) 저항성(抵抗性)에 관(關)한 연구(硏究))

  • Park, Hyoun Kyu;Kim, Byung Soo;Lee, Woo Sung
    • Current Research on Agriculture and Life Sciences
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    • v.4
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    • pp.7-11
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    • 1986
  • Nine Korean local cultivars and 34 PI lines of pepper were tested for resistance to anthracnose (Colletotrichum dematium). Red ripe fruits were harvested, punctured and inoculated by spraying and dropping a conidial suspension of Colletotrichum dematium. Resistance was evaluated by measuring the diameter of ripe rot lesions developed on and around the puncture. The results obtained are as follows : 1. PI 201232, PI 224451, PI 257044, PI 257119, PI 257099, PI 224433, PI 244668, PI 257102, PI 173877, Namji, Cheongryong, and Seodong were the least diseased and considered to be resistant. 2. PI 241670, PI 244670, and PI 224423 were the most diseased and considered to be susceptible. 3. Others were in between the two extremes and considered to be intermediate.

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A Study on the Depth of the Lumbar Epidural Space from the Skin in Parturients (산모의 요추부 경막외강 깊이에 대한 고찰)

  • Park, Chan-Heum;Song, Pil-Oh;Shin, Myong-Keun;Kim, In-Kyu;Lee, Seang-Ho
    • The Korean Journal of Pain
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    • v.10 no.1
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    • pp.73-76
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    • 1997
  • Background : Epidural anesthesia is now accepted as a popular technique for pain relief and anesthesia. However, accidental dural puncture may occur during placement of the epidural needle. This study was undertaken to evaluate difference of the epidural depth between parturients and non-parturients. Method : Eighty non-parturients receiving epidural anesthesia were assigned to group I, and eighty parturients whose body weight had not yet increased over 15 kg from pregnancy were assigned to group II. With patients in lateral decubitus position, 18 guage Tuohy needle was punctured by approaching at $L_{3-4}$ interspace. Epidural space was identified using loss-of-resistance to air technique. Result : Epidural depth was 4.18 cm and 4.25 cm in group I and group II respectively. There was no significant statistical difference in body mass index(BMI) and ponderal index(PI) (p<0.05), nor in epidural depth between the two groups. Conclusion : Epidural needle need not be placed deeper in parturients than in nonparturients.

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