• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.240-247
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• 2005

In order to analyze effects of strain rate on consolidation characteristics on Busan clay, a series of constant rate of strain(CRS) consolidation tests with different strain rate and incremental loading test(ILT) were performed. From experimental test results, it was found that the preconsolidation pressure was dependent on the corresponding strain rate occurred during consolidation process. Also, consolidation curves normalized with respect to preconsolidation pressure gave a unique stress-strain curve. Coefficient of consolidation and permeability estimated from CRS test had a tendancy to converge to a certain value at normally consolidated range regardless of strain rate. An increase in excess pore pressure without change of total stress was noted on the incremental loading test after the end of loading.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.200-203
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• 2011

Supersonic ejectors are simple mechanical components, which generally perform mixing and recompression of two fluid streams. Ejectors have found many applications in engineering. In aerospace engineering, they are used for high altitude testing (HAT) of a propulsion system by reducing the pressure of a test chamber. It is composed of three major sections: a vacuum test chamber, a propulsive nozzle, and a supersonic exhaust diffuser (SED). This paper aims at the improvement in HAT facility by focusing attention on the vertical firing rocket test stand with shock generators. Shock generators are mounted inside the SED for improving the pressure recovery. The results clearly showed that the performance of the ejector-diffuser system was improved with the addition of shock generators. The improvement comes in the form of reduction of the starting pressure ratio and the vertical height of test stand. It is also shown that shock generators are useful in reducing the total pressure loss in the SED.

• 한국기계가공학회지
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• 제21권2호
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• pp.73-78
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• 2022

The test apparatus that can be protected from the high-temperature combustion flame and coolant injection was successfully manufactured. In this study, the coolant-injection module had a controllable consistent pressure, and the entire combustion module was protected using a nonflammable composite liner. Every flange was designed in accordance with the DIN standard, and the entire body of the module was designed in accordance with the EN 13445 code. Additionally, the hydraulic pressure test was performed in accordance with the 2014/68/EU directive and EN 13445 standard. Finally, after manufacturing, performance tests (such as pressure tests) were conducted to verify the reliability and safety.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.421-426
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• 2010

With hydraulic noise test facility, a variety of tests were performed to investigate the pulsation pressure generation mechanism and its transmission characteristics and to derive the noise control methodology. Many experiments were carried out by changing average pressure, flow rate, pump speed, hose length and MCV spool condition. From the test results, the correlations between pulsation pressure and other design parameters, such as static pressure, flow rate and MCV spool opening area and length of hose, were found out. And also each contribution factors were evaluated from the regression analysis. By changing hose length, the pulsation pressure resonance phenomenon was investigated. In order to find out the pulsation pressure reduction measures pulsation pressure analysis, such as pulsation pressure of hydraulic pump itself and pulsation pressure of hydraulic system, by using AMESim were studied. In addition hydraulic silencer was developed based on the Helmholtz resonator. And its performance was evaluated by installing the silencer at the excavator.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3039-3042
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• 2012

Pressure tensors at the planar surface of liquid-vapor argon are evaluated from the virial theorem, Irving-Kirkwood, and Harasima versions using a test-area molecular dynamics simulation method through a Lennard-Jones intermolecular potential at two temperatures. We found that the normal and transverse components of the pressure tensor, $p_N(z)$ and $p_T(z)$, obtained from the virial theorem and Harasima version are essentially the same. The normal component of the pressure tensor from Irving-Kirkwood version, $p_N^{IK}(z)$, is shown to be a nearly constant at the lower temperature, independent of z, as agreed in a previous study, but not for $p_N^H$(z), while the transverse components, $p_T^{IK}(z)$ and $p_T^H(z)$, are almost the same. The values of surface tension for both versions computed from $p_N(z)-p_T(z)$ are also the same and are fully consistent with the experimental data.

• 대한임상전기생리학회지
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• 제1권2호
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• pp.69-76
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• 2003

The purpose of this study was to determine the effect of transcutaneous electrical nerve stimulation(TENS) on the alteration of pressure pain threshold of myofascial trigger points. We used fifty nine patients with upper trapezius mayofascial pain syndrome. Participants classified according to each group in conventional TENS(high rate, low intensity) and acupuncture like TENS(low rate, high intensity). The test was measured continuously pre test, post-test by algometer. The following results were obtained; 1. Pressure pain threshold were significantly increased in all groups(p<.001). 2. In comparison between groups, pressure pain threshold were not significantly differenced. These results lead us to the conclusion that each method by TENS were significantly increased pressure pain threshold of upper trapezius trigger points. Therefore, a further direction of this study will be to provide more evidence that TENS method have an effect on pressure pain threshold of myofascial trigger points.

• 한국수소및신에너지학회논문집
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• 제32권3호
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• pp.172-179
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• 2021

The drop impact analysis was carried out on Type 4 pressure containers, and the degree of damage to the falling environment was predicted and determined using smoothed particle hydrodynamics (SPH) techniques. The purpose of the design and the optimization process of the winding pattern of the pressure vessel of the composite material is to verify the safety of the container in actual use. Finally, an interpretation process that can be implemented in accordance with domestic test standards can be established to reduce the cost of testing and containers through pre-test interpretation. The research on the fall analysis of pressure vessels of composite materials was conducted using Abaqus, and optimization was conducted using ISIGHT. As a result, the safety of composite pressure vessels in the falling environment was verified.

• 한국전문물리치료학회지
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• 제16권4호
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• pp.1-7
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• 2009

The active-knee-extension (AKE) test has been used to measure hamstring muscle length. The traditional AKE test measures the popliteal angle to the point of resistance with a 90-degree flexion of the hip fixed by straps, while the stabilized AKE test measures the popliteal angle to the point of resistance with a 90-degree flexion of the hip stabilized using a pressure biofeedback unit providing lumbopelvic stabilization. The purpose of this study was to determine test-retest reliability of the traditional AKE test and stabilized AKE test. Twenty healthy adults participated in the study. The popliteal angles were measured with a digital inclinometer during each test. To assess the test-retest reliability between the 2 test sessions, intraclass correlation coefficients (ICCs) were calculated. The intrasubject coefficient of variation ($CV_{intra}$) was also calculated. To compare the traditional and stabilized AKE tests for changes in pressure, paired t-tests were applied. The results of this study were as follows: 1) ICCs(3,1) value for test-retest reliability was .96 in the traditional AKE test, and was .98 in the stabilized AKE test. 2) The maximal $CV_{intra}$ was 33.7% in the traditional AKE test and 15.7% in the stabilized AKE test. 3) Differences of $6.1{\pm}2.1$ mmHg in pressure were measured in the traditional AKE test, and differences of $1.2{\pm}1.0$ mmHg in pressure were measured in the stabilized AKE test. The results show the traditional and stabilized AKE test to be highly reliable, with test-retest reliability. However, the stabilized AKE test represented less variation and more stabilization than the traditional AKE test. Further study is needed to measure the inter-rater reliability of the stabilized AKE test for generalization and clinical application.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.809-812
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• 2008

현재 KS와 ASTM, BS 등에 규정되어 있는 블리딩 시험방법은 수직 원통 용기에 일정량의 모르타르를 채우고 시간이 경과함에 따라 변화하는 블리딩량과 부피팽창을 측정하는 방법이다. 블리딩 측정 시간은 KS에서는 3시간과 20시간으로 규정되어 있으며, ASTM과 BS에서는 블리딩은 타설 후 3시간에 측정하고 부피변화는 24시간 후에 측정하는 것으로 규정되어 있는 등 시험에 비교적 많은 시간이 소요되는 특징이 있다. 모르타르의 블리딩을 측정하는 또 다른 시험법으로 가압거름을 이용한 방법이 있다. 이는 압력을 가하여 미세한 직경의 공극을 가지는 필터를 통과하는 물의 양을 측정하는 방법으로 간접적으로 블리딩양을 예측하는 방법이다. 1971년 Schupack에 의해 고안된 방법으로 빠른 시간에 결과를 측정할 수 있다는 장점이 있는 반면, 아직 연구가 미흡하여 실험결과와 블리딩양과의 상관관계등에 대한 정립이 미흡한 상태이다. 따라서, 본 연구에서는 가압거름방법에 의한 시험 방법과 기존의 시험 방법을 비교하여 가압거름방법에 대한 타당성을 검증하고, 블리딩 양에 대한 상관관계를 도출하였다.

• 대한토목학회논문집
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• 제42권4호
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• pp.501-508
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• 2022

지하수위 회복을 위한 함양정 운영시 필요 기술은 지반이 파괴에 도달하지 않는 최대 주입압을 결정하는 것이다. 고전적인 토질역학에 기초한 수치해석과 실내시험을 통하여 사질토와 점성토의 항복에 도달하는 최대 주입압력을 추론하였다. 수치해석에서는 주입압력에 따른 점성토의 구속압력 감소에 따른 파괴시, 사질토는 유출동수 경사에 따른 파이핑 발생시 주입압력을 최대 한계압으로 결정하였다. 실내시험에서는 간극수압이 높아지는 것을 배압 증가를 통하여 구현하였으며, 사질토 경우 유효응력이 0이 되기전 최대 배압의 93 %에서 급격한 체적변형이 발생하였다. 점성토의 경우는 유효응력이 0에 도달할 경우 방사방향 변형율이 1.5 %에 도달하였으나 급격한 체적변형이 발생하지 않았다. 따라서 상기 결과에 근거하여 함양정의 최대 주입압력을 수치해석과 실내시험으로 결정할 수 있었다.