• Title/Summary/Keyword: Opening Pressure

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Study of Pressure Cooling of Agricultural Products Using a Pallet Bin (팔레트 빈(pallet bin)을 이용한 농산물의 차압통풍 냉각 연구)

  • Jeong, Hoon;Yun, Hong-Sun;Lee, Hyun-Dong;Kim, Young-Keun;Lee, Won-Ok
    • Food Science and Preservation
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    • v.15 no.6
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    • pp.847-851
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    • 2008
  • The handling and processing of agricultural products in Korea is done manually. Small plastic boxes, nets, and corrugated cardboard boxes are used as containers during harvesting, sorting and other product handling operations. However, these practices are labor-intensive, time-consuming, require various kinds of packing materials, and are expensive because of high operating costs. To overcome these problems, the use of pallet bins with pre-cooling and storage features for handling and processing bulk farm products was investigated. The airflow resistances through bulk potato, onion and mandarin stocks were measured, and the pallet bins and a pressure pre-cooling device were manufactured. The opening ratio, bed depth and airflow rate through bulk potato, onion and mandarin in the pallet bin were defined with regression equations. The cooling rates of bulk potato, onion and mandarin were 0.8C/h ($21.7{\rightarrow}0C$, 14.5 h), 0.4C/h ($15.4{\rightarrow}.0C$, 32.2 h) and 0.7C/h ($13.7{\rightarrow}C$, 18.8 h), respectively, with the pressure pre-cooling system. Temperature deviances for storage of bulk potato, onion and mandarin were 0.12C, 0.12C and 0.17C, respectively.

Development of Integrated Type Main Frame and Downhole Sonde Apparatus for Hydraulic Packer Testing in Seabed Rock under High Water Pressure (고수압 해저지반 수리특성 조사용 일체형 메인 프레임과 공내 측정장치 개발)

  • Bae, SeongHo;Kim, Jangsoon;Jeon, Seokwon;Kim, Hagsoo
    • Tunnel and Underground Space
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    • v.28 no.3
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    • pp.258-276
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    • 2018
  • The accurate and quantitative ground information on the hydraulic conductivity characteristics of rock mass is one of the key factors for evaluation of the hydro-geological behaviour of rock mass around an excavated opening under high water pressure. For tunnel and rock structures in seabed, where the sea acts as an infinite source of water, its importance become greater with increasing construction depth below sea level. In this study, to improve the problems related with poor system configuration and incorrect data acquisition of previous hydraulic packer testing equipment, we newly developed an integrated main frame and 30 bar level waterproof downhole sonde apparatus, which were optimized for deep hydraulic packer test in seabed rock mass. Integration of individual test equipment into one frame allows safe and efficient field testing work on a narrow offshore drilling platform. For the integrated type main frame, it is possible to make precise stepwise control of downhole net injection pressure at intervals of $2.0kg_f/cm^2$ or less with dual hydraulic oil volume controller. To ensure the system performance and the operational stability of the prototype mainframe and downhole sonde apparatus, the field feasibility tests were completed in two research boreholes, and using the developed apparatus, the REV(Representative Elementary Volume) scale deep hydraulic packer tests were successfully carried out at a borehole located in the basalt region, Jeju. In this paper, the characteristics of the new testing apparatus are briefly introduced and also some results from the laboratory and in-situ performance tests are shown.

Model Test Study on the Reinforcing Effect of Inclined System Bolting (경사볼트의 보강효과에 대한 모형시험 연구)

  • Lee, Jea-Dug;Kim, Byoung-Il;Piao, Ming-Shan;Yoo, Wan-Kyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.5C
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    • pp.231-238
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    • 2012
  • The rockbolt functions as a main support, which restricts enlargement of the plasticity area and increases stability in the original ground around tunnels, and prevents a second deformation of an excavated surface by supplementing vulnerability arising from opening of the excavated surface. System bolting is generally applied if ground conditions are bad. System bolting is generally installed perpendicular to the excavation direction in every span. If a place is narrow, or it is difficult to insert bolts due to construction conditions, it may be connected and used with short bolts, or installed obliquely. In this study, laboratory model tests were performed to analyze the effect of the ground being reinforced by inclined bolts, based on a bending theory that assumes that the reinforced ground is a simple beam. In all test cases, deflections and vertical earth pressures induced by overburden soil pressure were measured. Total of 99 model tests were carried out, by changing the installation angle of bolts, lateral and longitudinal distance of bolts, and soil height. The model test results indicated that when the installation angle of bolts was less than $75^{\circ}$, deflections of model beams tended to increase rapidly. Also, the relaxed load that was calculated by earth pressure was rapidly increased when the installation angle of bolts was less than $75^{\circ}$. However, the optimum installation angle of inclined bolts was judged to be in the range of $90^{\circ}{\sim}75^{\circ}$. Also, as might be expected, the reinforcement effect of bolts was increased when the longitudinal and lateral distance of bolts was decreased.

A study on the use of fire hydrants as a heat wave reduction facility through hydraulic analysis of water supply network (상수관망 수리해석을 통한 폭염 저감 시설로써의 소화전 활용방안연구)

  • Hong, Sung Jin;Choi, Doo Yong;Yoo, Do Guen
    • Journal of Korea Water Resources Association
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    • v.54 no.12
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    • pp.1215-1222
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    • 2021
  • In this study, a study on how to use a fire hydrant as a heat wave reduction facility through hydraulic analysis of the water supply pipe network was conducted. Assuming that the fire hydrant installation point is open for heat wave reduction, the water pressure at each point was derived. And the reduction rate of the temperature according to the hydrant watering was compared with the watering area according to the operation of the watering truck. The watering area according to the opening of the fire hydrant was calculated by deriving the pressure value at the node where the fire hydrant was installed through hydraulic analysis of the water pipe network, and then using the watering radius relational expression according to the pressure value. As a result of applying the proposed methodology to two real city areas, the temperature reduction effect of the watering method by a fire hydrant can be derived lower than the watering method by a watering truck according to the difference in the absolute watering area. However, unlike a watering truck, a fire hydrant does not have a relative restriction on the amount of water supply and is expected to allows continuous divided spraying of the same area.

A Literatural Investigation of Diagnosis Methods and Evaluation Outcomes for the Clinical Trials on Temporomandibular Disorders (측두하악장애 임상연구에 사용된 진단 및 평가기준에 대한 문헌적 고찰)

  • Moon, Byung-Heon;Choi, Young-Jun;Yoo, Su-Bin;Ju, Yeung-Guk;Song, Seong-Bae;Song, Gwang-Chan;Seo, Ji-Yeon;Choi, Hee-Seung
    • Journal of Korean Medicine Rehabilitation
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    • v.26 no.4
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    • pp.45-55
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    • 2016
  • Objectives The aim of this review is to provide fundamental data for temporomandibular disorders diagnosis and evaluation criteria which can be used in clinical trial. Methods We investigated the clinical studies on temporomandibular disorders via PubMed. Also, we searched domestic articles through "OASIS", "NDSL", "KISS", "Korean Traditional Knowledge Portal (KTKP)". The articles we focused on were the recent decade from 2007 to 2016. A total of 139 studies were analyzed: 42 domestic articles and 97 overseas articles. This study focuses on the diagnosis and evaluation criteria on temporomandibular disorders. Results 1) In diagnosis criteria, Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was used 14 times in domestic articles and 63 times in overseas articles. Clinical symptoms were used 13 times in domestic articles, 17 times in overseas articles. 2) In evaluation criteria, Visual Analog Scale (VAS) was used as a pain scale 12 times in domestic articles, 63 times in overseas articles. Pressure Pain Threshold (PPT) was used 16 times in overseas articles. Whereas, no clinical trials used PPT in domestic articles. In psychological scale, Symptom Checklist-90-Revised (SCL-90-R) was used 6 times. However, SCL-90-R was used 2 times in domestic articles. ROM(Maximum Mouth Opening (MMO), Maximum Comfortable Opening (MCO) were used 24 times in overseas. In domestic articles, MMO was counted 12 times, while MCO was counted 5 times. Conclusions This research reviewed the tendency of using diagnosis methods and evaluating outcomes of the clinical on TMD. It is expected that this investigation would develop further treatment for TMD in the Korean Medicine.

Study on the improvement of microdialysis method for measuring brain amino acids in systemic morphine treated rats (Morphine을 전신투여한 랫드의 뇌에서 분비되는 amino acid 성 신경전달물질 측정을 위한 미세투석법의 개선에 관한 연구)

  • Lee, Jang-hern;Beitz, Alvin J
    • Korean Journal of Veterinary Research
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    • v.38 no.3
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    • pp.535-543
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    • 1998
  • In the present study, we designed and constructed new microdialysis probe in order to improve the efficacy and accuracy of microdialysis method. In addition, extracellular concentrations of GABA, glutamate, aspartate and glycine were monitored with new designed probe in the lateral portion of the ventrocaudal periaqueductal gray using unanesthetized and unrestrained rats. Furthermore, the effect of opiates on release of these amino acids, especially GABA, was analyzed by measuring their concentration in PAG dialysates following veratridine administration in the presence of systemic morphine. The results were summerized as follow : 1. The damaging rates of 1.0mm or 1.5mm window probe were 12.5% or 42.8%, respectively. In the group using 1.5mm window probe, the damaging area was extended into mesencephalic aqueduct because of microdialyzing pressure. 2. Because of the unique design of our probes with an opening facing one side, dialysis occurs in a hemisphere($600{\mu}m$ in mediolateral direction and $100{\mu}m$ in opposite side of the dialysis probe) around the opening rather than in a spherical shaped configuration which is typical of most commercially available probe designs. 3. Glutamate, taurine and glycine were present in the highest concentration in the dialysate sample obtained before treatment with veratridine, whereas, aspartate and GABA were present in the lowest concentration. 4. The concentration of all 5 amino acids increased significantly following $75{\mu}m$ veratridine perfusion into lateral ventrocaudal PAG. 5. There was no significant difference between basal and peak amino acid concentrations according to window sizes. 6. Morphine had no effect on baseline concentrations of amino acids in dialysates obtained from the lateral PAG as compared to saline treated controls. However, following veratridine treatment, morphine selectively affected GABA release in the lateral ventrocaudal PAG as compared to saline treated controls. These results suggest that GABAergic interneurons in the PAG are inhibited by opioids. Therefore, endogenous enkephalins or endorphins may directly inhibit intrinsic GABAergic intemeurons and block their tonic inhibition of PAG-NMR projection neurons. Moreover, new designed probes demonstrate improved efficiency and accuracy in collecting samples as compared to commercial types of microdialysis probes.

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Wind Tunnel Test Study on the Characteristics of Wind-Induced Responses of Tall Buildings with Openings (중공부(中空部)를 가진 고층건축물(高層建築物)의 풍응답(風應答) 특성(特性)에 관한 풍동실험(風洞實驗) 연구(硏究))

  • Kim, Dong Woo;Kil, Yong Sik;Ha, Young Cheol
    • Journal of Korean Society of Steel Construction
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    • v.17 no.4 s.77
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    • pp.499-509
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    • 2005
  • The excessive wind-induced motion of tall buildings most frequently result from vortex-shedding-induced across-wind oscillations. This form of excitation is most pronounced for relatively flexible, lightweight, and lightly damped high-rise buildings with constant cross-sections. This paper discusses the aerodynamic means ofmitigating the across-wind vortex shedding induced in such situations. Openings are added in both the drag and lift directions in the buildings to provide pressure equalization. Theytend to reduce the effectiveness of across-wind forces by reducing their magnitudes and disrupting their spatial correlation. The effects of buildings with several geometries of openings on aerodynamic excitations and displacement responses have been studied for high-rise buildings with square cross-sections and an aspect ratio of 8:1 in a wind tunnel. High-frequency force balance testshave been carried out at the Kumoh National University of Technology using rigid models with 24 kinds of opening shapes. The measured model's aerodynamic excitations and displacement were compared withthose of a square cylinder with no openings to estimate the effectiveness of openings for wind-induced oscillations. From these results, theopening shape, size, and location of buildings to reduce wind-induced vortex shedding and responses were pointed out.

An Experience of a Country in Transition and the Change of North Korea : An Adaptation of the 'Myanmar Model' (체제변동국가의 경험과 북한의 변화: '미얀마 모델'의 적용 가능성)

  • JANG, Jun Young
    • Journal of International Area Studies (JIAS)
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    • v.22 no.2
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    • pp.305-330
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    • 2018
  • The purpose of this article is to examine whether Myanmar's experience in which dealing with the most exemplary change among rogue states or pariah state in the 21st century is feasible for North Korea's case. Recently, North Korea's willingness to dialogue, reform and open is similar to the precedent in which the Myanmar military junta dismantled its ruling system and turned over transition period through general elections in 2010 and 2015 each. The so-called 'Myanmar Model' refers to a country branded as a rogue state which has been under the international sanctions and pressure, and opening its political system and the market by choosing transformation. However, rapid changes in speed across the entire society after opening up are impossible because the political elite is only the leading role and implementation in the transition. In case of Myanmar, military culture has penetrated into society due to such a long-lasting military dictatorship, and even democratic bloc has become accustomed to authoritarian decision-making process. Furthermore, the "reserved area" of the old regime still exists in a deformed political structure that can not retrieve the interests of the military. Therefore there could not be achieved political development in term of qualification. North Korea also appears unlikely to achieve political and economic assessment in a short period of time, as civil society has not appeared due to its long dictatorship and very low economic development levels. Like Myanmar, North Korea is also likely to control the pace and direction of upcoming reforms and open, as the dictator or most powerful person chose to reform and open up. Therefore, if North Korea moves toward the 'Myanmar Model', there will be high expectations of new changes in the short term, but it could be delayed or stalled in the mid and long term.

INFLAMMATORY SYNOVIAL CYST OF THE TEMPOROMANDIBULAR JOINT: A CASE REPORT (측두하악관절에 발생한 염증성 활액낭)

  • Cho, Myung-Chul;Huh, Jong-Ki;Hong, Soon-Won;Kim, Jin-Tae;Jeon, Kug-Jin;Kim, Hyung-Gon
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.30 no.3
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    • pp.292-295
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    • 2008
  • Temporomandibular joint cysts usually occur between the second and fourth decade of life. There is a female predominance to male of approximately 3 to 1. The patients complain of swelling, pain and sometimes decreased mouth opening. Synovial cysts of the temporomandibular joint seem to develop by an increase of intraarticular pressure due to trauma or inflammation which causes capsular herniation. However, if inflammatory synovial cysts develop by an increase of synovial fluid into inflammation tissue in the capsule without capsular herniation, a differential diagnosis should include synovial chondromatosis and synovitis. This is a case report of a synovial cyst developed in a capsule of the temporomandibular joint.

Characteristics of Temperature Control by Hot-gas Bypass Flow Rate on Industrial Water Cooler (핫가스 바이패스 유량에 따른 산업용 냉각기의 온도제어 특성)

  • Baek, Seung-Moon;Choi, Jun-Hyuk;Byun, Jong-Yeong;Moon, Choon-Geun;Lee, Ho-Saeng;Jeong, Seok-Kwon;Yoon, Jung-In
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.8
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    • pp.1129-1136
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    • 2009
  • The paper presents the performance characteristics for a cooling system using EEV. The water cooler was used to reduce thermal deformation and contraction due to high speed of machine tools and the EEV was used for capacity control for water cooler. The apparatus was designed for hot-gas bypass system which a hot-gas can flows from outlet of compressor to the inlet of evaporator. This experiment is the intermediary study for precise temperature control through PID control. The results show that the evaporator pressure increased and refrigeration capacity decreased as the EEV opening step of hot-gas bypass increased. These results can be used as basic data for the design of effective water cooler.