• Title, Summary, Keyword: 관통력

Search Result 65, Processing Time 0.05 seconds

Prestrain-induced Reduction in Skin Tissue Puncture Force of Microneedle (초기변형률에 의한 미소바늘의 피부조직 관통력 감소)

  • Kim, Jonghun;Park, Sungmin;Nam, Gyungmok;Yoon, Sang-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.40 no.10
    • /
    • pp.851-856
    • /
    • 2016
  • Despite all the recent advances in biodegradable material-based microneedles, the bending and failure (especially buckling) of a biodegradable microneedle during skin tissue insertion remains a major technical hurdle for its large-scale commercialization. A reduction in skin tissue puncture force during microneedle insertion remains an essential issue in successfully developing a biodegradable microneedle. Here, we consider uniaxial and equibiaxial prestrains applied to a skin tissue as mechanophysical stimuli that can reduce the skin tissue puncture force, and investigate the effect of prestrain on the changes in skin tissue puncture force. For a porcine skin tissue similar to that of humans, the skin tissue puncture force of a flat-end microneedle is measured with a z-axis stage equipped with a load cell, which provides a force-time curve during microneedle insertion. The findings of this study lead to a quantitative characterization of the relationship between prestrain and the skin tissue puncture force.

Studies on Strength of Netting (3) Joint Strength of Twisted-Jointed Netting (그물감의 강도에 관한 연구 (3) 관통형 그물감의 마디의 강도)

  • KIM Dai An
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.9 no.4
    • /
    • pp.293-298
    • /
    • 1976
  • 1) The decrease in strength of netting twines at the twisted joint is regarded to be due mainly to tile frictional force between plied yarns, but tile rate of decresae is within $5\%$ in filament twines and 5 to $10\%$ in spun twines. 2) The variation of the twisted joint strength with the angle between the two adjacent bars draws a parabola flaying the minimum value at tile angle of $90^{\circ}$. The minimum value was revealed as about $90\%$ of the strength at the angle of $0^{\circ}$ in wet spun twiness, but regarded to hi negligibly small filament twines. 3) The knot strength is about $30{\pm}5\%$of the twisted joint strength.

  • PDF

A Study on Puncture Properties of Short-fiber Reinforced Rubber (단섬유 강화고무의 관통 특성 연구)

  • Ryu, Sang-Ryeoul;Lee, Dong-Joo
    • Composites Research
    • /
    • v.19 no.6
    • /
    • pp.16-22
    • /
    • 2006
  • The puncture properties under various conditions were investigated for the optimum conditions to yield the best properties. Fiber aspect ratio(AR: length of fiber/diameter of fiber), interphase condition and fiber content were considered as variables which impact the puncture force and friction force. The puncture force of short-fiber reinforced rubber increases up to 3.4 times compared to the virgin material. The better interphase condition shows the higher puncture force at given fiber AR and fiber content. The friction force of the matrix and reinforced rubber with a fiber AR below 155 does not exist. The friction force of the reinforced rubber with the good interphase condition and high fiber AR is higher than puncture force of matrix. Overall, it was found that the interphase condition, fiber AR and fiber content have an important effect on the puncture properties.

The Maximum Needle Piercing Force through Fabrics Dyed with Loess (황토염색직물의 최대침관통력)

  • 장정대
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.23 no.7
    • /
    • pp.971-979
    • /
    • 1999
  • The experiment was conducted on five different kinds of fabrics dyed with loess. The sewability of fabrics dyed with loess by measuring the maximum needle piercing forces(MPF) through fabrics has been studied, MPF measurement using tensile tester was done 60 times for each fabrics at fixed low speed of 300mm/min. The nature of the loess on the dyed fabrics was physically jammed betweenthe fibers or adhered to the surface of fibers in the form of the fine particles so that the MPF through fabrics increases extremely in proportion to the increase of loess uptake and the plying number of fabrics dyed with loess. This results indicate that the MPF through fabrics is affected by mean value of the coefficient of friction on the surface of fabric(MIU) and cloth cover factor(Kc) in this experiment. Fabric was finished with softner to decrease the MPF during sewing operation, The MPF through softner finished fabric was decreased remarkably.

  • PDF

Prelinimary Engagement Effect Analysis of Isotropic Kinetic Energy Warhead (등방성 운동에너지 탄두의 교전 효과 예비 분석)

  • Shim, Sang-Wook;Hong, Seong-Min;Seo, Min-Guk;Tahk, Min-Jea
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.43 no.5
    • /
    • pp.440-448
    • /
    • 2015
  • Kinetic energy(KE) rod warhead system is a new interceptor which combines advantages of existing ones. This system is less dependant on a precision guidance than direct hit type warhead and gives high penetration rates than blast fragmentation type warhead. In this paper, isotropic KE rod warhead system is introduced with detonation/deployment model. A penetration effects of the deployed rods are calculated using TATE penetration equation. Also, an engagement performance analysis method is suggested. Finally, an optimal detonation time and engagement geometry is derived by Monte-Carlo simulation in various engagement situation using the performance analysis factor.

Stress Concentration Ratio According to Penetration Rate of Composite Ground Reinforced with GCP (GCP로 개량된 복합지반의 관통률에 따른 응력분담비)

  • Na, Seung-Ju;Kim, Daehyeon;Lee, Ik-Hyo;Lee, Kang-Il
    • Journal of the Korean Geosynthetics Society
    • /
    • v.16 no.2
    • /
    • pp.35-45
    • /
    • 2017
  • Gravel compaction pile (GCP) is widely used as it increases the bearing capacity of soft ground and reduces the consolidation settlement. Stress concentration ratio for design is dependent on the area replacement, surcharge pressure, depth and penetration rate. However, a range of stress concentration ratio obtained through field, laboratory experiments and numerical analysis is large. But since the main objective of the study is to evaluate the stress concentration ratio and settlement for both area replacement ratio and penetration rate through numerical analysis. Numerical analysis using the finite element program ABAQUS 6.12-4 has been performed for the composite ground with GCP. As a result, the stress concentration ratio at the points except for the point of top is in the range of 1.21-5.36, 1.19-5.45, 2.16-5.60 for 60%, 80% and 100% penetration, respectively. In general, as the penetration rate and area replacement ratio increases, the stress concentration ratio tends to increase.

Changes in Textural Properties of Korean Radish and relevant Chemical, Enzymatic Activities during Salting (염장과정 중 무의 조직감과 이와 관련된 화학적, 효소활성 변화)

  • Rhee, Hee-Seoup;Lee, Gui-Ju
    • Journal of the Korean Society of Food Culture
    • /
    • v.8 no.3
    • /
    • pp.267-274
    • /
    • 1993
  • This study was aimed to investigate the changes in textural properties of Korean radish and relevant chemical, enzymatic activities during salting. During salting, pH was decreased and total acidity was increased. The maximum compression and puncture forces of Korean radish were decreased significantly whereas cutting force was increased. From the force-distance curves, the break point and maximum force point disappeared in salted Korean radish whereas these appeared apparently in fresh one. Also, the number of peak obtained by three types of test from salted Korean radish was decreased. Hot water soluble pectin and 0.4% Na-hexametaphosphate soluble pectin were increased whereas 0.05 N-HCl soluble pectin were decreased significantly. Polygalacturonase activity were increased in Korean radish solid(RS) and Korean radish juice(RJ) until 4 days of salting. Pectin esterase activity were decreased in RS and RJ. Cx-cellulase activity did not appear initially, however, they began to show their activities after 2 days of salting and were increased in RJ although it was low.

  • PDF

The elastic bucking strength of axially compressed tubular member with through-gusset connection (관통한 가셋트판이 부착된 압축 강관 부재의 탄성좌굴내력)

  • Kim, Woo-Bum;Lim, Ji-Youn
    • Journal of Korean Society of Steel Construction
    • /
    • v.13 no.2
    • /
    • pp.133-141
    • /
    • 2001
  • A tubular member holding an axially through-gusset connection is often used to transmit axial compression in a steel truss structures. The elastic buckling loads of the member is affected by the stiffness ratio($\beta$) and the length ratio(G) because of two elements with different properties. In current code, however, the strength is evaluated with an effective length factor k=0.9 without considering the above effect. Therefore this study analyzed a theoretical mechanism based on the elasticity theory and performed a finite element analysis to investigate the influence parameters on the elastic buckling strength of axially loaded member.

  • PDF

An Investigation of the functioning and Side Effects of Linear Shaped Charges (선형 성형폭약의 기능적 측면에 대한 고찰)

  • Lim Seok-Sin;Worsey Paul
    • Explosives and Blasting
    • /
    • v.23 no.4
    • /
    • pp.45-55
    • /
    • 2005
  • 일반적 의미의 성형폭약이라 함은 폭약 중에 빈공간이 존재하여 표면쪽으로 개방되어 있는 한덩이의 고폭약을 말한다. 이런 이유로 절단 단면의 형상은 주로 V 자형을 이루고 있으며 보통 V자의 뽀족한 부분이 기폭부분이 된다. 성형폭약은 그 생김새를 기준으로 크게 2가지로 나눌 수가 있는데 원뿔형과 선형이 그것이다. 원뿔형 성형폭약은 그 초기 발전단계부터 군용 대장갑용으로 명성을 떨쳤으며 현재에도 많은 연구가 진행되고 있는 상태이다. 이에 비해 선형 성형폭약은 철구조물 해체나 여러 용도의 민간/상업용 절단도구로 많이 쓰이고 있는데 두 번의 세계전쟁을 치루며 엄청난 규모의 물질적 인적 지원을 바탕으로 발전한 원뿔형 성형폭약에 비해서 턱없이 연구실적이 부족한 상태이다. 이 논문에서는 일반적인 선형 성형폭약의 관통력에 대한 연구가 아닌 기능적 측면에 대한 연구결과를 서술하며, 기능적 측면상 중요한 몇 개의 항목에 대한 수량화, 정의 및 연구가 이루어진다. 그 항목으로는 발전거리(run up distance), 이격거리(stand off distance), 기폭위치에 따른 절단모양, 파편 분간 형상 등이 있으며 각 항목에 대한 하류 항목들은 본문에서 다루어진다. 모든 실험은 University of Missouri-Rolla, Rock Mechanics and Explosives Research Center 에서 이루어 졌으며 대부분의 실험은 500grain/ft 선형성형폭약을 사용하여, 기폭 후 철제목표물을 관통한 형상 및 관통 단면을 관찰하는 형식으로 이루어졌다.

Effects of Preheating Treatment and Chitosan Addition on the Textural Properties of Korean Radish during Salting (무의 염장과정 중 조직감의 변화에 대한 예열처리 및 Chitosan 첨가효과)

  • Rhee, Hee-Seoup;Lee, Gui-Ju
    • Journal of the Korean Society of Food Culture
    • /
    • v.9 no.1
    • /
    • pp.53-59
    • /
    • 1994
  • This study was attempted to investigate the effects of preheating treatment and chitosan addition on the textural properties of Korean radish during salting. For this study, we determined the changes in textural properties by compression, puncture, cutting tests respectively and the changes in pectin fractions were also determined. Sensory parameters such as hardness, crispness and toughness were evaluated by sensory analysis and their results were correlated with those by Instron. The results were as follows. The compression force of nonpreheated Korean radish was increased by chitosan addition, whereas that of preheated one was decreased during salting. The puncture force from all the samples of Korean radish decreased, however, chitosan addition showed higher puncture force. The cutting force of nonpreheated Korean radish increased during salting and those from nonpreheated and preheated ones were increased by chitosan addition. During salting hot water soluble pectin(HWSP) of nonpreheated Korean radish increased and 0.4% Na-hexametaphosphate soluble pectin(HXSP) and 0.05 N-HCl soluble pectin(HCISP) decreased respectively. However, HXSP was decreased by preheating treatment. On the contrary, the results were reversed by chitosan addition. Hardness and crispness of nonpreheated Korean radish decreased and toughness increased respectively during salting. However, toughness was decreased by preheating treatment and hardness was increased by chitosan addition. Compression and puncture forces were highly correlated with sensory parameters such as hardness and crispness, whereas cutting force was more correlated with toughness. From these results, it seems that the textural properties were improved by chitosan addition in both nonpreheated and preheated Korean radish. The preheating treatment was effective in the early stage of salting. However, combination of both treatments showed little effect during salting.

  • PDF