• Title/Summary/Keyword: Direct measurement method

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Numerical simulation of compressive to tensile load conversion for determining the tensile strength of ultra-high performance concrete

  • Haeri, Hadi;Mirshekari, Nader;Sarfarazi, Vahab;Marji, Mohammad Fatehi
    • Smart Structures and Systems
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    • v.26 no.5
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    • pp.605-617
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    • 2020
  • In this study, the experimental tests for the direct tensile strength measurement of Ultra-High Performance Concrete (UHPC) were numerically modeled by using the discrete element method (circle type element) and Finite Element Method (FEM). The experimental tests used for the laboratory tensile strength measurement is the Compressive-to-Tensile Load Conversion (CTLC) device. In this paper, the failure process including the cracks initiation, propagation and coalescence studied and then the direct tensile strength of the UHPC specimens measured by the novel apparatus i.e., CTLC device. For this purpose, the UHPC member (each containing a central hole) prepared, and situated in the CTLC device which in turn placed in the universal testing machine. The direct tensile strength of the member is measured due to the direct tensile stress which is applied to this specimen by the CTLC device. This novel device transferring the applied compressive load to that of the tensile during the testing process. The UHPC beam specimen of size 150 × 60 × 190 mm and internal hole of 75 × 60 mm was used in this study. The rate of the applied compressive load to CTLC device through the universal testing machine was 0.02 MPa/s. The direct tensile strength of UHPC was found using a new formula based on the present analyses. The numerical simulation given in this study gives the tensile strength and failure behavior of the UHPC very close to those obtained experimentally by the CTLC device implemented in the universal testing machine. The percent variation between experimental results and numerical results was found as nearly 2%. PFC2D simulations of the direct tensile strength measuring specimen and ABAQUS simulation of the tested CTLC specimens both demonstrate the validity and capability of the proposed testing procedure for the direct tensile strength measurement of UHPC specimens.

Disagreement between direct and indirect blood pressure measurements obtained from minipigs

  • Lee, Won-Jae;Park, Lisa Soyeon
    • Korean Journal of Veterinary Research
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    • v.58 no.3
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    • pp.131-136
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    • 2018
  • Blood pressure (BP) measurement plays a pivotal role in veterinary medicine for diagnosing cardiovascular disorders and monitoring anesthesia of animals. Although indirect BP measurement has been widely applied to monitor BP because of its convenience and non-invasiveness, it is still unclear whether indirect BP measurement is compatible with direct BP measurement in minipigs. In addition, the effect of animal posture during BP measurement is not well understood in minipigs despite its importance to cardiovascular performance. Therefore, both systolic and diastolic arterial BPs in minipigs were measured via femoral artery catheterization for direct BP measurement and using a compressive cuff as an indirect BP measurement under the dorsal or right lateral recumbent postures. Numerical values were processed by the Bland-Altman method to calculate the bias ${\pm}$ SD and the limits of agreement (LOA). In accordance with the American College of Veterinary Internal Medicine guidelines, the results between direct and indirect BP measurements were determined as apparent disagreements in both systolic and diastolic arterial BPs under all postures because of large bias ${\pm}$ SD and wide LOA. The results of the present will help prevent misinterpretation of the anesthetized patient's condition during monitoring of BP by indirect measurement.

Analysis of Difference between Direct Measurement and 3-D Automatic Measurement According to Classification of Side Figure of Elderly Women (고령 여성의 측면체형 분류에 따른 직접측정치와 3차원 자동측정치간의 차이 분석)

  • Chung, Juwon;Nam, Yun-Ja;Park, Jinhee
    • Fashion & Textile Research Journal
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    • v.21 no.5
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    • pp.627-639
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    • 2019
  • This study analyzes differences between the results of 3D direct measurements and automated measurements for Korean elderly females according to age groups, side somatotype, and BMI groups. This study compares the measurement differences of the direct and the 3D automated measurements for women between the ages of 70 to 85, according to age group, BMI group, and side somatotype. A comparison of the results of the direct measurement and the 3D automated measurements for elderly women show that a meaningful discrepancy exists for 29 items out of 33 items. Furthermore, the results of comparing the average error tolerance recommended by ISO20685 shows that 30 items out of 33 items exceeded ISO recommendations. The results of the automated measurement program shows a higher degree of accuracy for straight postures; however, this unsuitable for postures of elderly women with a changed somatotype. The analysis results of the measurement difference indicate the suitability of the automatic measurement programs is found to be high for stood postures, while problems seem to exist on several items along with an automated program is not appropriately used due to posture and part of body changes for elderly women. Therefore, it is recommended to develop an algorithm, that reflects the body changes of elderly women first and then upgrade the automated program equipped with a measurement size method. It is hoped that the study results can be utilized as base data for improving the automated measurement program.

A Study on a Measurement Method for 2D Anthropometry using Digital Camera (디지털 카메라를 이용한 2D 인체계측법 연구)

  • 손희정;김효숙;최창석;손희순;김창우
    • The Research Journal of the Costume Culture
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    • v.11 no.1
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    • pp.11-19
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    • 2003
  • This study suggests the new 2D anthropometric method using digital camera. It is used MK2001 program that can convert 2D measurements to 3D measurements. To improve that it is measured 100 college students with direct and indirect anthropometric method. The measurements were processed by the SPSS ver10 Statistical Package. The average, standard deviation, and t-test were calculated for each category. Most measurements by 2D measurements are higher than direct measurements but degree. The difference between direct and indirect measurements is less than 2cm. In the results of t-test, height measurements including other 16 measurements which is easy to measure have no meaningful difference within 1cm. The depth measurements are most high difference. The result of each measurement proves that MK2001 program (2D anthropometry method using digital camera) is available for measuring the human body.

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Experimental verification and improvement of heat transfer tube local wall temperature measurement method

  • Jiabao Liu;Xiaxin Cao;Peixun Yang
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4317-4328
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    • 2023
  • To ensure the measuring accuracy of the wall temperature, the outer wall temperature measurement values by using three kinds of thermocouple welding methods were analyzed and evaluated in the paper, including single-point flush-mounted in the wall groove method, single-point insert-mounted in the wall groove, and outer surface direct welding method, based on the application of a tube-in-tube condensing heat exchanger. And the impacts of silver, tin, and thermal resistance adhesive as filling materials on wall temperature measurement were also investigated, and the results were compared to that obtained without filling materials. The results showed that the wall temperatures measured by the three welding methods were lower than the theoretically calculated value. And the wall temperature measured by the outer surface direct welding method was lowest under the same experimental conditions. The wall temperatures measured by single-point flush-mounted and insert-mounted in the wall groove methods were also affected by different welding filling materials. It was found that the greater the thermal resistance of filling materials, the smaller the heat loss. By analyzing the reasons for the low measured value of wall temperature, a new wall temperature measurement method was developed to improve the accuracy of the current measurement method. Meanwhile, the outer wall temperature measurement experiments of vertical and horizontal heat transfer tubes were carried out to validate and calibrate the improved outer wall temperature measurement method. The results showed that the average outer wall temperature deviation measured by the improved wall temperature measurement method ranged from - 0.82% to +2.29% for vertical tubes and - 4.75% to - 1.44% for horizontal tubes, and the improved measurement method had good measurement accuracy.

A Study on Left and Right Shape and Deformation of Feet of Korean Adults (한국 성인 발 형태의 좌우 및 변형 연구)

  • Im, Hyeon-Gyun;Park, Su-Chan;Choe, Gyeong-Ju;Kim, Jin-Ho;Park, Se-Jin
    • Journal of the Ergonomics Society of Korea
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    • v.20 no.1
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    • pp.73-86
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    • 2001
  • An analysis of anthropometric data of feet of Korean adults was made in this study. Anthropometric data were measured with the direct measurement method and indirect measurement method. Martin scales and a tapeline were used for direct measurement. Digital images taken with a digital camera as an indirect measurement method were analyzed using AutoCAD program. Total 114 adults aged from 20's to 40's participated in this study. Especially right and left feet were measured. Right and left side were compared and differences according to age were compared too. Feet shape, arch height, and deformation of toe were analyzed. The comparison between right and left foot showed that many subjects had different anthropometric data in their feet. Feet deformation including arch height and claw toe shape showed very serious status. Close and continuous attention to feet deformation is strongly needed.

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Direct Measurement of the VLSI Interconnection Line Capacitances Using a Grounded Shield Plate (접지된 Shield Plate를 이용한 집적회로의 배선용량 측정)

  • 강래구;전성오;신윤승
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.3
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    • pp.302-307
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    • 1988
  • A noble interconnection line capacitance measurement method to be able to remove the measurement errors from the probe pad to substrate stray capacitance has been proposed and verified. The measurement errors in the capacitance measurement, which usually be involved from the probe pad to substrate stray capacitance, can easily be removed by isolating the metal probe pad from the substrate with a grounded shield plate between the probe pad the substrate. The measurement results by using this improved capacitance measurement method were compared with the calculations by two-dimensional computer simulations.

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ECG Measurement Method during Sleep with Array of Capacitive Electrodes Attached to Bed (침대에 부착된 용량성 전극 배열을 이용한 수면 중의 심전도 측정)

  • Lim, Y.G.;Kim, K.K.;Park, K.S.;Jeong, D.U.
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.521-524
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    • 2005
  • In order to measure ECG in daily life, a new ECG measurement method on bed was developed. The provided method does not require any direct conductive contact between the instrument and bare skin, so that it does not cause the uncomfortable feel of touch and the possible skin trouble which are typical shortcomings of the conventional conductive contact ECG measurement. The provided method utilized an array of high-input-impedance active electrodes fixed on the mattress and an indirect-skin-contact ground made of a large conductive textile sheet and laid on lower area of the mattress. A thin cotton bedcover covered the mattress, the electrodes, and the conductive textile and subjects lay on the mattress over the bedcover. ECG was obtained successfully. However its signal quality is lower and the motion artifact is larger than direct-contact measurement. Careful measurement setup was needed to reduce the motion artifact originated from variation in static electricity. From the ECG obtained by the provided method, R-peak could be discriminated easily and the information about the position and the posture of the subject could be obtained.

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Comparison of Cardiac Output Determination by Direct Fick and Thermodilution Method in Man (인체에서 Pick 원리 및 열희석법에 의한 심박출량 측정의 비교 연구)

  • 장병철
    • Journal of Chest Surgery
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    • v.14 no.3
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    • pp.228-234
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    • 1981
  • Measurement of cardiac output by thermodilution method is easy to perform and can be repeated at very short intervals and offers a number of theoretical and practical advantages. The purpose of this paper is to reevaluate the accuracy and reproducibility of the thermodilution cardiac output by comparing the results with those obtained by the direct Fick technique. From January through April 1981 [4 months], 26 simultaneous cardiac output measurements were made using thermodilution and direct Fick methods in 12 patients in the intensive care unit of Severance Hospital following open heart surgery. The average age of the patients was $34.8{\pm}12.0$ [SD] years [range; 17-57 years]. For cardiac output determination by thermodilution technique [$CO_TD$], a Swan-Ganz Thermodilution Catheter, Model 93A-131-7F [Edwards Laboratories], a Cardiac Output Computer, Model 9520A, and Strip Chart Recorder, Model 9810 [Edwards Laboratories] were used. For the determination of cardiac output by direct Fick principle [$CO_Fick$], a Van Slyke Manometric Apparatus [Thomas] for the measurements of arteriovenous oxygen content difference and a Collin`s Respirometer with Kymograph for the measurement of oxygen consumption were used. The correlation between the simultaneously measured $CO_TD$ and $CO_Fick$ was found to be $CO_Fick$ = 0.95.$CO_TD$ + 0.1073, [r= 0.9777, P < 0.001 ]. For 26 double or triple determinations of $CO_TD$, the values ranged from 1.77 L/min to 6.66 L/min, with a reproducibility of 2.18%. The maximum difference of $CO_TD$ for $CO_Fick$ was between +11.99% and -12,99% [$Mean{\pm}SD$ = $6.07{\pm}3.97$%]. Measurement of cardiac output by thermodilution method provides a simple, rapid, reproducible and highly accurate method for multiple cardiac output measurements suitable for use at the bedside. Comparison of Cardiac Output Determination by Direct Fick and Thermodilution Method in Man.

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A Study of the Characteristics of Thickness Distribution of Liquid Sheet Formed by Two Low Speed Impinging Jets (저속 충돌 제트로 생성되는 액막의 두께 분포 특성 연구)

  • Han, M.J.;Jeon, Y.U.;Seo, T.W.;Kang, B.S.
    • Journal of ILASS-Korea
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    • v.26 no.1
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    • pp.26-32
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    • 2021
  • In this study, the thickness of the liquid sheet formed by two low speed impinging jets was measured by the direct contact method. The effects of jet velocity and liquid viscosity on the thickness were analyzed and the results were compared with theoretical modeling and optical thickness measurement results. The liquid film thickness decreased as the radius and circumferential angle increased. The jet velocity did not affect the liquid film thickness as predicted in theoretical modeling. In the theoretical modeling, there was no influence of the fluid properties on thickness, but in the case of low viscosity liquids, the thickness was predicted high, and it was well matched in high viscosity liquids. The direct measurement results showed no significant difference from the optical measurement results, thus confirming the reliability of the optical measurement method.