약물 투여에 따른 기니피그 대장 운동 측정을 위한 압력센서 개발

박재순,박정호,김응보,조성환,장수정,정연호,Park, Jae-Soon,Park, Jung-Ho,Kim, Eung-Bo,Cho, Sung-Hwan,Jang, Su-Jeong,Joung, Yeun-Ho 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.1

In this paper, in order to quantify the peristalsis occurrence in a guinea pig's large intestine, a miniaturized air-gap capacitive pressure sensor was fabricated through micro-electro-mechanical system (MEMS). The proposed pressure sensor is a two-layered biocompatible polyimide substrate consisting of an air-gap capacitive plates between the substrates. The proposed pressure sensor was designed with a careful consideration of the structure and motility mechanism of the guinea pig's large intestine. Artificial pellets were mounted on a prototype pressure sensor to provide some redundancies in the form of size and shape of the guinea pig feces. Capacitance of a prototype sensor was recorded to be 2.5 ~ 3 pF. This capacitance value was later converted to count value using a lab fabricated data conversion system. Sensitivity of the pressure sensor was recorded to be below 1 mmHg per atmospheric pressure. During in vivo testing, artificial peristalsis caused by drug injection was measured by inserting the prototype pressure sensor into the guinea pig's large intestine and pressure data obtained due to artificial peristalsis was graphed using a labview program. The proposed pressure sensor could measure the pressure changes in the proximal, medial, and distal parts of the large intestine. The results of the experiment confirmed that pressure changes of guinea pig's large intestine was proportional to the degree of drug injection.

욕창방지용 휠체어 쿠션 신기술의 압력 비교 : 예비 연구

황보승우,김종배 대한보조공학기술학회 2015 대한보조공학기술학회지 Vol.7 No.1

Objective : The purpose of this study was to introduce new technologies of pressure ulcer preventive wheelchair cushion and identify whether the pressure differs from these new technologies. Methods : This study was conducted for total 6 days, from 18th to 23rd of June, 2015. The participants were one healthy man and a woman each. Three new types of pressure ulcer preventive wheelchair cushion were used for this study. Each of the wheelchair cushions was provided for 45 minutes and X3 Medical v6.0 was used for comparing the measured pressure. The peak pressure of the first frame (Pre Peak Pressure), the peak pressure of the last fram (Post Peak Pressure), and the average peak pressure of the first, middle, and last frames (Average Peak Pressure) were analysed by X3 Medical v6.0. Results : As a result, Pre, Post, and Average Peak Pressures of Java cushion were all lowest among three cushions. In Lock cushion, Post and Average Peak Pressures were highest. Galaxy cushion indicated highest Pre Peak Pressure. Conclusion : Since the peak pressure areas of the three cushions are different, it’s difficult to conclude which cushion was the most effective for preventing pressure ulcer. However, Java cushion had lower Peak Pressure than both Galaxy and Lock cushion when applied for 45 minutes. Considering the technologies of the three wheelchair cushions, further studies are required for comparing these cushions when applied for longer time with a clear standard. Moreover, the study must be conducted with current long-term wheelchair users instead of non-disabled subjects. 목적 : 본 연구의 목적은 욕창방지용 휠체어 쿠션의 신기술을 소개하고, 이 신기술에 따른 압력이 차이가 있는지를 알아보고자 함이다. 연구방법 : 본 연구는 2015년 6월 18일부터 23일까지 6일간 진행되었다. 일반 성인 남녀 2명을 대상으로 진행하였으며, 실험은 신기술의 욕창방지용 휠체어 쿠션 세 종류를 사용하였다. 각각의 쿠션은 45분간 적용되었으며, 측정된 압력 값을 비교하기 위해 X3 Medical v6.0을 사용하였다. 압력 측정의 맨 첫 번째 구간의 최대 압력 값, 맨 마지막 구간의 최대압력 값, 그리고 첫 번째, 중간, 마지막 구간을 합하여 3으로 나눈 평균 최대 압력 값을 각각 분석하였다. 결과 : 각 쿠션별로 측정된 압력 값을 분석한 결과, Java 쿠션이 최대 압력의 초기, 후기, 평균값 모두 가장 낮게 나타났다. Lock 쿠션은 최대 압력의 후기 값과 평균값이 가장 높았다. Galaxy 쿠션은 최대 압력의 초기 값이 가장 높았다. 결론 : 3가지 쿠션의 각 최대 압력 값이 부위에 따라 다르기 때문에 욕창 예방에 가장 효과적인 쿠션을 결론짓기에는 다소무리가 있으나, 45분 동안 적용한 기준으로 측정한 최대 압력의 값은 Java 쿠션이 Galaxy와 Lock 쿠션보다 낮게 나타났다. 그러나 욕창방지용 휠체어 쿠션 세 종류가 가지고 있는 기술의 특성을 고려하였을 때, 명확한 기준을 설정하여 보다 긴 시간동안의 압력 값을 비교하는 연구가 필요할 것으로 예상되며, 일반인이 아닌 실제 휠체어를 장기간 사용하는 대상자로 연구를 진행해볼 필요가 있다.

유치원, 초등, 중등 학생들의 고체, 액체, 기체의 압력개념 유형분석

김효남 ( Kim Hyo Nam ),조부경 ( Jo Bu Gyeong ),백성혜 ( Baeg Seong Hye ) 한국교원대학교 과학교육연구소 2003 청람과학교육연구논총 Vol.13 No.1

Current Understanding of Pressure Natriuresis

( Eun Ji Baek ),( Sejoong Kim ) 대한전해질학회 2021 Electrolytes & Blood Pressure Vol.19 No.2

Pressure natriuresis refers to the concept that increased renal perfusion pressure leads to a decrease in tubular reabsorption of sodium and an increased sodium excretion. The set point of blood pressure is the point at which pressure natriuresis and extracellular fluid volume are in equilibrium. The term abnormal pressure natriuresis usually refers to the expected abnormal effect of a certain level of blood pressure on sodium excretion. Factors that cause abnormal pressure natriuresis are known. Sympathetic nerve system, genetic factors, and dietary factors may affect an increase in renal perfusion pressure. An increase in renal perfusion pressure increases renal interstitial hydrostatic pressure (RIHP). Increased RIHP affects tubular reabsorption through alterations in tight junctional permeability to sodium in proximal tubules, redistribution of apical sodium transporters, and/or release of renal autacoids. Renal autocoids such as nitric oxide, prostaglandin E2, kinins, and angiotensin II may also regulate pressure natriuresis by acting directly on renal tubule sodium transport. In addition, inflammation and reactive oxygen species may mediate pressure natriuresis. Recently, the use of new drugs associated with pressure natriuretic mechanisms, such as angiotensin receptor neprilysin inhibitor and sodium glucose co-transporter 2 inhibitors, has been consistently demonstrated to reduce mortality and hypertension-related complications. Therefore, the understanding of pressure natriuresis is gaining attention as an antihypertensive strategy. In this review, we provide a basic overview of pressure natriuresis to the target audience of nephrologists.

급수용 감압밸브의 비다이어프램 스템에서 압축스프링에 따른 유량 및 토출압력 효과

변재욱(Jae-Uk Byeon),김치호(Chi-Ho Kim),박성환(Seong-Hwan Park),이명원(Myung-Won Lee),강명창(Myungchang Kang) 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.5

The pressure reducing valve for water is controlled by the load of the compression spring and the force of the fluid acting on the diaphragm of the stem. Repeated upward and downward reciprocation of the pressure-reducing valve stem damages the diaphragm, resulting in leakage. In this study, we designed a stem without a diaphragm and adjusted the stiffness of the compressing spring. In order to select the spring stiffness, springs offering a stiffness of -20%, -10%, 0%, and 10% with respect to the stiffness of the compression spring attached to the existing pressure reducing valve stiffness. A prototype for the pressure reducing valve was fabricated and the pressure change was evaluated for the target static pressure (6 bar) by testing the pressure characteristics after mounting the modified stem and each compression spring. Evaluation of the pressure characteristics was carried out using ASSE 1003 and KS B 6153. In addition, the flow rates were compared by internal flow analysis of the conventional pressure reducing valve and the pressure reducing valve using the modified stems, and the flow analysis was performed using Solidworks flow simulation 2018. The spring stiffness was constantly discharged at the target static pressure of 3.793 kgf/mm, and the flow rate was increased by about 15% compared with the conventional pressure reducing valve.

흰쥐에서 외부압력에 따른 엉치부위 피부의 혈류 및 조직학적 변화

이호 ( Ho Lee ),조강희 ( Kang Hee Cho ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.1

We aimed to investigate the changes on blood perfusion and histological structures of sacral skin in rat by externally applied pressure. Sixty-four Sprague-Dawley rats were used. Pressure was applied to the sacral skin by a pressure column using a pressure delivery system and blood perfusion was monitored by a laser doppler flowmeter. Changes in blood perfusion were monitored before, during the application of pressure ranged from 9 mmHg to 468 mmHg for duration of 30 seconds by increment of 10 g of force. Macroscopic and histological changes were evaluated following pressure application ranged from 30 mmHg to 140 mmHg for duration of from 30 minutes to 5 hours. Blood perfusion decreased nonlinearly with increasing pressure and approached to 4.2 perfusion unit(PU) at 37~47 mmHg and maintained constantly with a pressure of 468 mmHg and following pressure release, reactive hyperemia was occurred. There was a marked change in the appearance of pressed skin as compared to normal skin. Histological changes were developed following pressure application of 100 mmHg for 30 minutes or more and45 mmHg for 1 hour or more.The pressure application of 45 mmHg for 3 consecutive 2 hour duration each made the apoptosis of the epidermis, dermis and skin appendage. Our findings are suggestive that position change per 2 hours is not enough for the prevention of pressure ulcer. Therefore, interval of position change should be reduced or pressure at body-bed interface should be reduced below 45 mmHg by specially made air mattress.

연구논문 : 다중회귀모형을 이용한 벤츄리가 없는 충격기류식 여과집진장치 압력손실 예측

서정민 ( Jeong Min Suh ),박정호 ( Jeong Ho Park ),조재환 ( Jae Hwan Cho ),진경호 ( Kyung Ho Jin ),정문섭 ( Moon Sub Jung ),이병인 ( Pyong In Yi ),홍성철 ( Sung Chul Hong ),시바쿠마르최금찬 ( S Sivakumar ),최금찬 ( Kum Chan Choi ) 한국환경과학회 2014 한국환경과학회지 Vol.23 No.12

In this study, pressure drop was measured in the pulse jet bag filter without venturi on which 16 numbers of filter bags (Ø140 × 850 ℓ) are installed according to operation condition(filtration velocity, inlet dust concentration, pulse pressure, and pulse interval) using coke dust from steel mill. The obtained 180 pressure drop test data were used to predict pressure drop with multiple regression model so that pressure drop data can be used for effective operation condition and as basic data for economical design. The prediction results showed that when filtration velocity was increased by 1%, pressure drop was increased by 2.2% which indicated that filtration velocity among operation condition was attributed on the pressure drop the most. Pressure was dropped by 1.53% when pulse pressure was increased by 1% which also confirmed that pulse pressure was the major factor affecting on the pressure drop next to filtration velocity. Meanwhile, pressure drops were found increased by 0.3% and 0.37%, respectively when inlet dust concentration and pulse interval were increased by 1% implying that the effects of inlet dust concentration and pulse interval were less as compared with those changes of filtration velocity and pulse pressure. Therefore, the larger effect on the pressure drop the pulse jet bag filter was found in the order of filtration velocity(Vf), pulse pressure(Pp), inlet dust concentration(Ci), pulse interval(Pi). Also, the prediction result of filtration velocity, inlet dust concentration, pulse pressure, and pulse interval which showed the largest effect on the pressure drop indicated that stable operation can be executed with filtration velocity less than 1.5 m/min and inlet dust concentration less than 4 g/m3. However, it was regarded that pulse pressure and pulse interval need to be adjusted when inlet dust concentration is higher than 4 g/m3. When filtration velocity and pulse pressure were examined, operation was possible regardless of changes in pulse pressure if filtration velocity was at 1.5 m/min. If filtration velocity was increased to 2 m/min. operation would be possible only when pulse pressure was set at higher than 5.8 kgf/cm2. Also, the prediction result of pressure drop with filtration velocity and pulse interval showed that operation with pulse interval less than 50 sec. should be carried out under filtration velocity at 1.5 m/min. While, pulse interval should be set at lower than 11 sec. if filtration velocity was set at 2 m/min. Under the conditions of filtration velocity lower than 1 m/min and high pulse pressure higher than 7 kgf/cm2, though pressure drop would be less, in this case, economic feasibility would be low due to increased in installation and operation cost since scale of dust collection equipment becomes larger and life of filtration bag becomes shortened due to high pulse pressure.

Pressure filtration of colloidal SiC particles

Yoshihiro Hirata,Yosuke Tanaka,Seiya Nakagawa,Naoki Matsunaga 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.3

The consolidation behavior of colloidal SiC particles (30 or 800 nm diameter) with and without polyacrylic ammonium (dispersant, PAA) at pH 7 was examined using a developed pressure filtration apparatus in the pressure range from 100 kPa to 19 MPa at a constant crosshead speed or at a constant compressive pressure of a piston. In the electrostatically-stabilized colloidal suspensions (5 vol%-30 nm SiC (powder A), 30 vol%-800 nm SiC (powder B)) without PAA, a phase transition from a well-dispersed suspension to a flocculated suspension occurred when the applied pressure exceeded a critical pressure (ΔPtc = 0.2−0.4MPa). The addition of PAA suppressed the phase transition. The height of the compressive piston as a function of filtration time at a constant applied pressure was simulated by an established filtration theory for a well-dispersed suspension and a newly-developed filtration theory for a flocculated suspension. The experimental results for both the suspensions of powders A and B with and without PAA were simulated well by the new model for flocculated suspension. The packing density of consolidated powders A and B in the filtration apparatus depended on the applied pressure, but the density after calcination was independent of the compressive pressure. The consolidation behavior of colloidal SiC particles (30 or 800 nm diameter) with and without polyacrylic ammonium (dispersant, PAA) at pH 7 was examined using a developed pressure filtration apparatus in the pressure range from 100 kPa to 19 MPa at a constant crosshead speed or at a constant compressive pressure of a piston. In the electrostatically-stabilized colloidal suspensions (5 vol%-30 nm SiC (powder A), 30 vol%-800 nm SiC (powder B)) without PAA, a phase transition from a well-dispersed suspension to a flocculated suspension occurred when the applied pressure exceeded a critical pressure (ΔPtc = 0.2−0.4MPa). The addition of PAA suppressed the phase transition. The height of the compressive piston as a function of filtration time at a constant applied pressure was simulated by an established filtration theory for a well-dispersed suspension and a newly-developed filtration theory for a flocculated suspension. The experimental results for both the suspensions of powders A and B with and without PAA were simulated well by the new model for flocculated suspension. The packing density of consolidated powders A and B in the filtration apparatus depended on the applied pressure, but the density after calcination was independent of the compressive pressure.

정수기용 감압밸브의 2차측 감압성능 개선에 관한 연구

이정연,이용주,김봄,김동묵 한국산학기술학회 2024 한국산학기술학회논문지 Vol.25 No.10

The pressure-reducing valve reduces the high pressure at the primary inlet to the target pressure at the secondary outlet. The pressure-reducing valve reduces the high pressure at the primary side inlet to the target pressure at the secondary side outlet. The performance of this pressure-reducing valve can be evaluated by the amount of pressure reduction from the primary side to the secondary side and the maintenance of a constant reduced pressure. The pressure-reducing valve of existing carbonated water purifiers can control the pressure reduction, but it does not maintain a certain pressure after pressure reduction. Therefore, there is a need for improvement measures to address the change in carbonated water taste because of changes in carbonation concentration, but research on this has been insufficient. This study developed a new pressure-reducing valve to improve its pressure-reducing performance and pressure-maintaining function. The developed pressure-reducing valve could reduce the input pressure by more than 80%, and the pressure after reduction had a fluctuation rate of approximately 0.63%.

An Experimental Study on Seepage within Shale Fractures due to Confining Pressure and Temperature

Jingping Wang,Haichun Ma,Peichao Feng,Qing Zhang,Jiazhong Qian,Xiaohui Tan,Lei Ma,Daoxiang Wu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9

Seepage of groundwater within rock fractures is widespread. The seepage conditions in the fractures can be affected by the stress and temperature conditions. Shale seepage conditions are a complicated coupling of stress and temperature. Experiments were carried out on shale samples containing three types of fractures: a single short fracture (type A), a single long fracture (type B), and symmetrical short fractures (type C). Three temperature conditions were set for type A. The coefficient C, which is defined as the ratio between the seepage pressure and the flow rate, is constant when the temperature effects are slight. Linear correlations between the coefficient C and the temperature were simulated. For type B, four confining pressures were applied using the confining pressure pump. As the confining pressure increases, the seepage pressure increases. The seepage pressure distribution is nonlinear when the flow rate increases to 6 ml/min under a confining pressure of 12 MPa. For type C, three temperature conditions with three confining pressure conditions were analyzed to determine the seepage pressure. The effects of the confining pressure on the seepage pressure are different from those of type B. Nonlinear curves occur under confining pressures of 3 MPa and 6 MPa at 50°C. The seepage pressure values at 70°C are smaller than those at 30°C and 50°C. The coefficient C contour is depicted for the experimental ranges of temperature and confining pressures. The small value region of coefficient C occurs at about 6 MPa and 50°C. The nonlinear increase in the seepage pressure in the fractures occurred when the confining pressure was larger for a single fracture and when the confining pressure was lower for double fractures.