• Title/Summary/Keyword: Rate of penetration

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Percussive Drilling Application of a Tubular Reciprocating Translational Motion Permanent Magnet Synchronous Motor

  • Zhang, Shujun;Norum, Lars E.;Nilssen, Robert;Lorenz, Robert D.
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.4
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    • pp.419-424
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    • 2012
  • This paper presents a tubular reciprocating translational motion permanent magnet synchronous motor for percussive drilling applications for offshore oil & gas industry. The motor model and rock model are built up by doing force analysis of the motor and analyzing the physical procesof impact. The optimization of input voltage waveforms to maximize the rate of penetration is done by simulations. The simulation results show that the motor can be utilized in percussive drilling applications and achieve a very large impact force. Simulation results for optimization also show that second harmonic input voltage produces a higher rate of penetration than the sine wave and fourth harmonic input voltages.

A Study on Flow Properties of Semisolid Dosage Forms

  • Shon, Sung-Gil;Lee, Chi-Ho
    • Archives of Pharmacal Research
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    • v.19 no.3
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    • pp.183-190
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    • 1996
  • There are a wide variety of semi-solid ointments used for healing the skin diseases, whose therapeutic and skin penetration abililties may greatly differ from one another depending on the compositions of ointment vehicles. A computer optimization technique was applied to obtain the optimum formula of o/w type ointment giving the in vitro maximum absorption rate through hairless rat skin membrane. Some of the formulations were selected to find out a relationship between skin penetration of ointment and its Theological characteristics. The experimental value of absorption rate obtained from the ointment by optimum formula agreed well with the theoretical value obtained from a polynomial regression analysis, Three kinds of ointments selected among 15 formulations were obtained with a concentric cylinder type rheometer (Model; Rheolab SM-HM Physica, Germany) at 20, 30, 40 and $50^{\circ}C$ for rheograms of rhelolgical properties of o/w type ointments. As the temperature was raised, all products showed a decrease in both shear stress and yield values. The higher skin penetration, the lower shear stress showed.

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An Experimental Study on the Performance of Semi-Closed Loop Ground Heat Exchanger (반밀폐형 지중열교환기 성능에 관한 실험적 연구)

  • Kim, Ook-Joong;Yeom, Han-Kil;Lee, Chun-Woo
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.542-545
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    • 2007
  • A semi-closed loop ground heat exchanger is proposed and its performance is compared through the measuring the effective thermal conductivity of the ground. In-situ tests based on the line source model are carried out to evaluate the thermal characteristics of each ground heat exchanger which has different penetration water flow rate. The test results show the increasing effective thermal conductivity of ground as the penetration water flow rate(PWFR) is increased. Therefore, the higher thermal performance of the proposed semi-closed ground heat exchanger can be expected.

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Optimization of GTAW Parameters for Horizontal Welding of a STS316L Pipe (STS316L 강관의 수평자세 용접을 위한 GTAW 용접조건의 최적화)

  • Lee, Hyoung-Keun;Bang, Kyoung-Sik
    • Journal of Welding and Joining
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    • v.33 no.5
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    • pp.47-52
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    • 2015
  • In this study, it was tried to analyze the effects of welding parameters on the weld penetration and aspect ratio when a STS316L pipe was welded in a horizontal position by GTAW. Experiments were systematically designed using a L18 orthogonal array, and the effects of welding parameters were statistically analyzed by ANOVA(Analysis of Variance). The shielding gas type has the largest effect on both the penetration and aspect ratio. The welding current type and shielding gas flow rate have a little effect on the penetration, whereas the electrode tip angle has a little effect on the aspect ratio. When welded at a selected welding condition, which is composed of He shielding gas, pulse current of 300/45 A, electrode tip angle of 90o, and shielding gas flow rate of 30 l/min, the estimated interval at least 95 % confidence was $1.99{\pm}0.18mm$ for the penetration and $0.31{\pm}0.04$ for the aspect ratio. From the confirmation experiments, the average penetration and aspect ratio were well agreed with the estimation as 1.96 mm and 0.30, respectively. Additionally, the effects of the welding speed and welding current on the penetration and aspect ratio were experimented and analyzed by linear regression. The penetration was linearly increased with the decrease of the welding speed and with the increase of the welding current, but the aspect ratio showed a tendency to a little decrease with the increase of both the welding speed and current.

Analysis of Human Spermatozoal Fertilizing Ability Using Zona -free Hamster Oocyte (투명대 제거 햄스터난자를 이용한 인간정자 침투능에 관한 연구)

  • Kim, J.M.;Suh, B.H.;Lee, J.H.;Chung, K.S.
    • Clinical and Experimental Reproductive Medicine
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    • v.16 no.1
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    • pp.15-21
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    • 1989
  • An in vitro fertilization assay employing zona-free hamster embryos was used to investigate human spermatozoal fertilitzing ability. Yanaghimarchi et al.(1976) first introduced this cross species fertilzation technique, with its application as a diagnostic tool for male infertility. Human spermatozoa were preincubated for 3 to 4 hrs in B W W medium at concentration of $4{\times}10^6$ sperm/ml prior to the addition to zona-free hamster embryos. After 3 hrs, human sperm was evaluated for fertilizing potential by the presence of swelling or decondencing sperm head in the cytoplasm. The results of penetration rates for sperm were as follow : 1. The average penetration rate of a 7 fertile donor group was $47.8{\pm}27.67%$(Range 14.3-98.0%) 2. The average penetration rate of 12 infertile patients with normal semen analysis was $21.7{\pm}26.9%$(Range 0-38.8%) 3. The average penetration rate of 10 infertile patients with semen abnormalities was $6.1{\pm}8.1%$(Range 0-25%)

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Experimental Study of Water Penetration Rate Via Graphene Oxide Membrane According to Driven Pressure Difference (산화 그래핀 맴브레인의 물투과 속도와 차압 조건 간 상관관계에 대한 실험적 연구)

  • Kim, Ji-Min
    • Journal of the Korean Society of Mechanical Technology
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    • v.20 no.6
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    • pp.858-864
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    • 2018
  • Graphene oxide (GO) laminate is a new promising material for water purification system, which has extraordinary permeability only for water molecule. It consists of numerous nano-channels, in which water molecules could be nano-confined, resulting in slip of the molecules for very fast transportation speed. In this study, water penetration rate via different thickness of GO membrane according to driven pressures are measured experimentally, so that speed of water molecules and permeability are evaluated. Generally, water penetration rate via a membrane with macroscopic-sized channel increases linearly with pressure difference between up and bottom side of the membrane, but that via GO membrane approaches asymptotic value (i.e. saturation) as like a log function. Moreover, the permeability of GO membrane was observed in inverse proportion to its thickness. Based on the experimental observations, a correlation for volume flux via GO membrane was suggested with respect to its thickness and external pressure difference.

Development of Dynamic Cone Penetration Tester Module for Slope Vulnerability Assessment and Correlation of Its Results with Standard Penetration Test Values (비탈면 취약도 평가를 위한 동적콘관입시험기 모듈개발과 표준관입시험값과의 상관관계 연구)

  • Chae, Hwi-Young;Kwon, Soon-dal
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.541-547
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    • 2021
  • To assess the stability of a slope and the likelihood of its loss or collapse requires information about the ground, such as the composition of the stratum and its mechanical characteristics. This information is generally gathered through standard penetration testing (SPT) and cone penetration testing. SPT is not widely used due to problems with accessing slopes, most of which are steep and without ramps. A drop cone penetrometer, a portable device that can make up for these shortcomings, can be used in a limited way in some circumstances. Therefore, we developed a portable drilling machine and a small dynamic cone penetration test module that can easily access a slope site and perform SPT. The correlation of the developed system's results with those from SPT was analyzed. Analysis of the correlation between the energy shear rate passing to the load during the different test types established that the energy shear rate is reflected in the test result. The correlation between corrected dynamic cone penetration testing and corrected SPT was Nd' = 3.13 N'.

Driveability Analysis of U-type Sheet Pile using WEAP Program (WEAP 프로그램을 이용한 U형 널말뚝의 항타관입성 해석)

  • Kim Byoung-Il;Kim Jae-Kyu;Lee Seung-Hyun;Lee Jong-Ku
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.4
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    • pp.671-678
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    • 2006
  • Vibratory pile driving has an advantage of reduced noise pollutions compared to impact pile driving and it has been very widely used in the installation of sheet piles. However, very little has been known about the driveability characteristics of sheet pile under vibratory driving. So, the proper sheet piles and vibratory hammer for an given soil profile and depth are determined on a empirical basis. In this study. the driveability of U-type sheet piles are analytically estimated using the commercial WEAP(Wave Equation Analysis of Piles) program. The WEAP analysis shows that penetration rate of sheet pile decreases as N value increases. And if penetration length is not over 20 meters, the rate of penetration decreases as the sectional area of sheet pile increases.

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Study on the characteristics of the plasma induced by lap-joint $CO_2$ laser welding of automotive steel sheets (자동차용 강판의 겹치기 $CO_2$ 레이저 용접에서 발생되는 플라즈마 특성에 관한 연구)

  • 남기중;박기영;이경돈
    • Laser Solutions
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    • v.5 no.1
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    • pp.33-42
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    • 2002
  • In order to investigate the characteristics of the plasma induced by lap-joint CO$_2$ laser welding of automotive steel sheets, the effects of welding speed, shield gas flow rate, gap size, and laser beam defocus to plasma intensity emitted from keyhole have been investigated. The plasma light is measured by fiber and photodiode. Also, the plasma images were captured by the high speed digital camera in 1000frames/sec in order to correlate the plasma light signal with plasma pattern. From the results, it is observed that the difference of the plasma intensity for between the deep penetration and partial penetration exists from 1.2 to 2 times. The plasma light intensity decreased in case of the deep penetration Is observed due to the exhausting of the plasma gas under the sheet. On the other hand, under the conditions of the deep penetration, the plasma intensity is significantly increased by controling the conditions decreasing the penetration depth. It was specially founded that the effect of 0.3mm gap size at partial penetration condition is approximately similar to deep penetration in 0mm gap. It is concluded that the plasma intensity is able to evaluate the penetration depth in lap-joint welding and appears to offer the most straightforward correlation to the welding process.

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Penetration mechanisms of non-deforming projectiles into reinforced concrete barriers

  • Dancygier, Avraham N.;Yankelevsky, David Z.
    • Structural Engineering and Mechanics
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    • v.13 no.2
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    • pp.171-186
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    • 2002
  • Static and dynamic penetration tests of reinforced concrete (RC) slab specimens are described and discussed. The experimental study was aimed at a better understanding of mechanisms that are involved in dynamic penetration, through their identification in static tests, and by establishing their relative influence in similar dynamic cases. The RC specimens were $80{\times}80-cm$ square plates, and they were made of 30 MPa concrete. The non-deforming steel penetrator was a 50-mm diameter steel rod with a conical nose of 1.5 aspect ratio. Impact penetration tests were carried out with an air gun, which launched the projectiles at velocities of up to 300 m/sec. The static tests were conducted using a closed loop displacement control actuator, where the penetrator was pushed at a constant rate of displacement into the specimen. The static tests reveal important mechanisms that govern the penetration process and therefore contribute to a better understanding of RC barriers resistance to non-deforming projectiles impact.