• Title/Summary/Keyword: Rate of penetration

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Penetration of Compacted Bentonite into the Discontinuity in the Excavation Damaged Zone of Deposition Hole in the Geological Repository (심층처분장 처분공 주변 굴착손상영역에 존재하는 불연속면으로의 압축 벤토나이트 침투)

  • Lee, Changsoo;Cho, Won-Jin;Kim, Jin-Seop;Kim, Geon-Young
    • Tunnel and Underground Space
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    • v.30 no.3
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    • pp.193-213
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    • 2020
  • A mathematical model to simulate more realistically the penetration of compacted bentonite buffer installed in the deposition hole into the discontinuity in the excavation damaged zone formed at the inner wall of the deposition hole in the geological repository for spent fuel is developed. In this model, the penetration of compacted bentonite is assumed to be the flow of Bingham fluid through the parallel planar rock fracture. The penetration of compacted bentonite is analyzed using the developed model. The results show that the maximum penetration depth of compacted bentonite into the rock fracture is proportioned to the swelling pressure of saturated compacted bentonite and the aperture of rock fracture. However, it is in inverse proportion to the yield strength of compacted bentonite. The viscosity of compacted bentonite dominates the penetration rate of compacted bentonite, but has no influence to the maximum penetration depth.

Study on the Clinical Validity of Sperm Penetration Assay (Sperm Penetration Assay의 임상적 타당성에 관한 연구)

  • Pang, Myung-Geol;Oh, Sun-Kyung;Shin, Chang-Jae;Kim, Jung-Gu;Moon, Shin-Yong;Chang, Yoon-Seok;Lee, Jin-Yong
    • Clinical and Experimental Reproductive Medicine
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    • v.20 no.1
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    • pp.1-7
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    • 1993
  • The present study was designed to test the validity of the semen analysis(S/A) and the sperm penetration assay(SPA) as a prognostic indicator of male fertility in 123 patients undergoing in vitro fertilization(IVF). We attempted to correlate the traditional semen parameters or the extent of sperm penetration in SPA with the results of human IVF rate or cleavage rate. Poor correlation was found between the results of S/A and human IVF rate(sensitivity, 80.6% ;specificity, 46.7%; positive predictive value, 91.6%;negative predictive value, 25%). Conversely, good correlation was found between the results of SPA and human IVF rate(sensitivity, 100% ; specificity, 80% ;positive predictive value, 97.3% ;negative predictive value, 100%). Our results corroborate the conclusion that SPA can be a valuable tool as a prognostic indicator of male fertilizing ability.

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Penetration Efficiency of Charged Particles in a Cylindrical Tube Connection with Electrical Voltage Difference

  • Song, Dong-Keun;Kim, Tae-Oh
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.E1
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    • pp.29-38
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    • 2007
  • A cylindrical tube connection that has a voltage difference and is separated electrically by an insulator was modelled. The penetration efficiencies of charged particles passing through the connector tube were investigated. Typically, as the particle size decreases and the applied voltage difference increases, the penetration efficiency decreases. To assess the effect of the electrode geometry, various lengths of electric insulator and aerosol flow rate with a fixed tube length and tube diameter were used when calculating penetration efficiencies. The comparison of penetration efficiencies for various electrode geometry setups suggests that the penetration efficiency can be described as a function of the product of applied voltage and electrical mobility of charged particles. The diffusion loss from this and previous studies are compared. Further, an explicit form for penetration efficiency is provided as a function of a new non-dimensional parameter, $Es(=Z_pV/U_{avg}W);\;P_{es}=0.2{\cdot}{\exp}(-Es/0.6342)+0.8{\cdot}{\exp}(-Es/4.7914)$.

Evaluation of Solid Surface Properties by Analysis of Liquid Penetration Rate into Powder Beds (분체층 내 액체 침투속도 해석에 의한 분체 표면성질의 평가)

  • Ha, Jong-Hak;Kim, Seong-Soo;Wang, Lin;Choi, Hee-Kyu
    • Korean Journal of Materials Research
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    • v.18 no.3
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    • pp.128-136
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    • 2008
  • Evaluation of the solid surface properties by an analysis of the liquid penetration rate into powder beds is very important in applications of powder products. The penetration rate is related the surface property in powder beds. In order to analyze the surface property of powders, the contact angle values of several powders were obtained using the Washbun equation and the Wicking method. The surface free energy value ${\gamma}S$ was divided into a polar component ${\gamma}S^p$ and a dispersion component ${\gamma}S^d$. Inorganic powders such as calcite were used as test samples. The effects of the particle size and the type of experimental liquid on the penetration rate were measured. It was confirmed that the surface free energy of the grinding sample is smaller than that of the classification sample.

Scale Effects of Warhead on Concrete Penetration (탄두의 콘크리트 관통 시 스케일 영향)

  • Kim, Seokbong;Lee, Changsoo;Yoo, Yohan
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.2
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    • pp.238-245
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    • 2017
  • This paper deals with the scale effects of warhead on concrete penetration. We investigated the scale effects using finite element analysis and Young's penetration equation. As the scale of penetration test decreases, the strain rate effects of target increases, and then strength of concrete target increases. This means the residual velocity and penetration depth of warhead decreases as the test model size decreases. Young's penetration equations are transformed with various penetrator mass and scale cases as a function of scale ratio. Penetration distance and residual velocity are not simply changed by the geometric scaling law.

A study on the rock fracture mechanism of cutter penetration and the assessment system of TBM tunnelling procedure

  • Baek, Seung-Han;Moon, Hyun-Koo
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.162-169
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    • 2003
  • Excavation by TBM can be characterized by a rock-machine interaction during the cutting process on a small scale, but on a large scale the interaction between the rock mass and TBM becomes very significant. For the planning and evaluation of TBM tunnelling it needs to understand rock fracture mechanism by a cutter or cutters on a small scale, and to estimate penetration rate, advance rate and utilization on a large scale. In this study rock chipping mechanism due to cutter-penetration is analysed by numerical simulation, showing that rock chipping is mainly occurred by tensile failure. Also, through the analysis of factors that affect on TBM procedures in various assessment systems, it is determined that the key elements that should be considered in the planning and evaluation of TBM tunnelling are classified into rock properties, the geological structures and properties of rock mass, and the structural and functional specifications of the machine. The user-friendly assessment tool is developed, so that penetration rate, advance rate and TBM utilization are evaluated from various input data. The tool developed in this study can be applied to a practical TBM tunnelling by understanding TBM tunnelling procedures.

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Use of the Stratum Corneum Reservoir for the Prediction of Skin Penetration

  • Cholee, Ae-Ri;Tojo, Kakuji
    • Journal of Pharmaceutical Investigation
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    • v.23 no.3
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    • pp.1-8
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    • 1993
  • A simple and quick method based on the transient diffusion theory for predicting the steady state rate of penetration of a drug after transdermal drug administration was proposed. The amount of drug entering the stratum corneum was determined by 20 strippings with an adhesive tape. From the profile of the amount of drug as a function of the number of strippings, the quantity of drug on the surface of stratum corneum was extrapolated. Based on the amounts of drug entering the stratum corneum during two time intervals $(t_1\;and\;t_2)$ within 1 hour after the application, the diffusion and partition coefficient were determined. Once the diffusion coefficient of the drug in the stratum corneum and the partition coefficient (stratum corneum/vehicle) were determined from the present approach, the steady-state flux of penetration across the stratum corneum was calculated. The steady-state rates of penetration of ascorbic acid and estradiol across hairless mouse skin were evaluated from this approach and compared with those obtained from ill vitro penetration experiment using excised hairless mouse skin. The data confirmed that the proposed method can predict the steady-state rate of penetration of these drugs across the stratum corneum.

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PWSCC growth rate model of alloy 690 for head penetration nozzles of Korean PWRs

  • Kim, Sung-Woo;Eom, Ki-Hyun;Lim, Yun-Soo;Kim, Dong-Jin
    • Nuclear Engineering and Technology
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    • v.51 no.4
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    • pp.1060-1068
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    • 2019
  • This work aims to establish a model of a primary water stress corrosion crack growth rate of Alloy 690 material for the head penetration nozzles of Korean pressurized water reactors. The test material had an inhomogeneous microstructure with bands of fine-grains and intragranular carbides in the matrix of coarse-grains, which was similar to the archive materials of the head penetration nozzles. The crack growth rate was measured from the strain-hardened materials as a function of the stress intensity factor in simulated primary water at various temperatures and dissolved hydrogen contents. The effects of strain-hardening, temperature, and dissolved hydrogen on the crack growth rate were analyzed independently, and were then introduced as normalizing factors in the crack growth rate model. The crack growth rate model proposed in this work provides a key element of the tools needed to assess the progress of a stress corrosion crack when detected in thick-wall Alloy 690 components in Korean reactors.

THE EFFECT OF PRIMER ON PENETRATION OF SEALANT (치면열구전색제의 열구 침투에 primer의 효과)

  • Jeong, Hye-Seon;Lee, Jae-Ho;Choi, Hyung-Jun;Choi, Byung-Jai
    • Journal of the korean academy of Pediatric Dentistry
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    • v.26 no.2
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    • pp.416-426
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    • 1999
  • The objective of this study is to confirm the effect of dentine bonding primer application on penetration of sealant. Extracted permanent molars were used to compare penetration success rate of control group (sealant application only) and experimental groups (sealant application after applying the primers of $Scotchbond^{TM}$ Multi-Purpose system and $All-Bond^{(R)}$ 2 system). The following results were obtained: 1. The experimental groups using the primers showed increased sealant penetration success rate to the base of fissure when compared to control group but there was no statistically significant differences(p>0.05). 2. The depth, width and 'depth/width' value of fissure had statistically significant effect on sealant penetration success rate(p<0.05). 3. The penetration success rate decreased about 0.9 times as the depth of fissure increased every $25{\mu}m$, and increased about 1.1 times as the width of the fissure orifice increased every $25{\mu}m$ and decreased about 0.6 times as the 'depth/width' value increased every 1. From the above results, it can be concluded that assure morphology had a great effect on sealant penetration and for better penetration, use of dentine bonding primer can be helpful but it needs more study in clinical bases.

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Improvement of Tunnelling Speed in Full-Face Mechanical Excavation (기계굴착에서 굴착속도의 발전경향분석)

  • Park, Chul-Whan;Park, Chan;Cheon, Dae-Sung;Synn, Joong-Ho
    • Tunnel and Underground Space
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    • v.17 no.3 s.68
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    • pp.225-233
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    • 2007
  • Because of Norwegian topography as valleys and fjords, a large number of tunnels has been built and 59 of them have been excavated by TBM for last 30 years. Prognosis technology has been developed and improved through lots of TBM experiences, and the NTNU prediction model has been completed. This paper focuses the improvement of net penetration rate and advance rate in 14 Norwegian and 4 Koran TBM tunnelling sites of which data were reported. Through this period, net penetration rate as well as advance rate were increased to double with the improvement of disc cutter size and cutter arrangement in Norway. These rates in Korea were also increased for 15 years even though the rates were lower compared to Norwegian. It is estimated that these low rates were mainly caused by using disc cutters less than 17 inch diameter. It is expected that net penetration rate and advance rate can be increased by improvement of machine and tunnelling technology, especially by using 17 or 19 inch of the disc cutter size in the Korean full face mechanical tunnelling site.