• 제목/요약/키워드: Elevated Pressure

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Intraocular Pressure and Its Determinants in Subjects With Type 2 Diabetes Mellitus in India

  • Biswas, Sayantan;Raman, Rajiv;Koluthungan, Vaitheeswaran;Sharma, Tarun
    • Journal of Preventive Medicine and Public Health
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    • 제44권4호
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    • pp.157-166
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    • 2011
  • Objectives: This study was conducted to show the intraocular pressure (IOP) distribution and the factors affecting IOP in subjects with type 2 diabetes mellitus (DM) in India. Methods: We measured the anthropometric and biochemical parameters for confirmed type 2 DM patients. A comprehensive ocular examination was performed for 1377 subjects aged > 40 years and residing in Chennai. Results: A significant difference in IOP (mean ${\pm}$ standard deviation) was found between men and women ($14.6{\pm}2.9$ and $15.0{\pm}2.8$ mmHg, p = 0.005). A significantly elevated IOP was observed among smokers, subjects with systemic hypertension and women with clinically significant macular edema (CSME). After a univariate analysis, factors associated significantly with higher IOP were elevated systolic blood pressure, elevated resting pulse rate and thicker central corneal thickness (CCT). In women, elevated glycosylated hemoglobin was associated with a higher IOP. After adjusting for all variables, the elevated resting pulse rate and CCT were found to be associated with a higher IOP. Conclusions: Systemic hypertension, smoking, pulse rate and CCT were associated with elevated intraocular pressure in type 2 DM. Women with type 2 DM, especially those with CSME, were more prone to have an elevated IOP.

AZ31B 마그네슘 합금의 온간 마찰 특성 연구 (Study of Frictional Behavior of AZ31B Mg Alloy at Elevated Temperature)

  • 한수식
    • 소성∙가공
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    • 제27권3호
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    • pp.160-164
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    • 2018
  • The success of warm forming of Mg alloy sheets is very dependent on its frictional behavior at elevated temperatures. The effects of contact pressure and sliding length on the frictional characteristics of AZ31B Mg alloy sheet were investigated at elevated temperature and at room temperature. The contact pressure range for the friction test was determined through FE analysis of the roof panel which is a candidate for Mg alloy application. According to the experimental results, the frictional behavior of the Mg alloy sheet is equally highly influenced by both sliding length and contact pressure at room temperature. At elevated temperatures, however, the sliding length has a more dominant influence on the frictional characteristics of the Mg alloy sheet than the contact pressure, if the contact pressure is lower than a certain level.

A study of aerodynamic pressures on elevated houses

  • Abdelfatah, Nourhan;Elawady, Amal;Irwin, Peter;Chowdhury, Arindam
    • Wind and Structures
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    • 제31권4호
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    • pp.335-350
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    • 2020
  • In coastal residential communities, especially along the coastline, flooding is a frequent natural hazard that impacts the area. To reduce the adverse effects of flooding, it is recommended to elevate coastal buildings to a certain safe level. However, post storm damage assessment has revealed severe damages sustained by elevated buildings' components such as roofs, walls, and floors. By elevating a structure and creating air gap underneath the floor, the wind velocity increases and the aerodynamics change. This results in varying wind loading and pressure distribution that are different from their slab on grade counterparts. To fill the current knowledge gap, a large-scale aerodynamic wind testing was conducted at the Wall of Wind experimental facility to evaluate the wind pressure distribution over the surfaces of a low-rise gable roof single-story elevated house. The study considered three different stilt heights. This paper presents the observed changes in local and area averaged peak pressure coefficients for the building surfaces of the studied cases. The aerodynamics of the elevated structures are explained. Comparisons are done with ASCE 7-16 and AS/NZS 1170.2 wind loading standards. For the floor surface, the study suggests a wind pressure zoning and pressure coefficients for each stilt height.

Thermal-pressure loading effect on containment structure

  • Kwak, Hyo-Gyoung;Kwon, Yangsu
    • Structural Engineering and Mechanics
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    • 제50권5호
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    • pp.617-633
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    • 2014
  • Because the elevated temperature degrades the mechanical properties of materials used in containments, the global behavior of containments subjected to the internal pressure under high temperature is remarkably different from that subjected to the internal pressure only. This paper concentrates on the nonlinear finite element analyses of the nuclear power plant containment structures, and the importance for the consideration of the elevated temperature effect has been emphasized because severe accident usually accompanies internal high pressure together with a high temperature increase. In addition to the consideration of nonlinear effects in the containment structure such as the tension stiffening and bond-slip effects, the change in material properties under elevated temperature is also taken into account. This paper, accordingly, focuses on the three-dimensional nonlinear analyses with thermal effects. Upon the comparison of experiment data with numerical results for the SNL 1/4 PCCV tested by internal pressure only, three-dimensional analyses for the same structure have been performed by considering internal pressure and temperature loadings designed for two kinds of severe accidents of Saturated Station Condition (SSC) and Station Black-out Scenario (SBO). Through the difference in the structural behavior of containment structures according to the addition of temperature loading, the importance of elevated temperature effect on the ultimate resisting capacity of PCCV has been emphasized.

압력변화에 따른 대향류 화염 연소특성 연구를 위한 가압 연소실 설계 (Design of a Combustion Chamber for Studying the Combustion Characteristics of Counterflow Flames at Elevated Pressure)

  • 안영종;구재원;최선;구자예;권오채
    • 한국수소및신에너지학회논문집
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    • 제28권3호
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    • pp.315-321
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    • 2017
  • A combustion chamber is designed and fabricated for studying the combustion characteristics of counterflow flames at elevated pressure and establishing the fundamental combustion database of counterflow flames. The combustion chamber design aims to allow the maximum operating pressure of 11 bar and be able to conduct flame visualization and the measurements of flame extinction limits, flame temperature and combustion emissions at elevated pressure. Preliminary tests for counterflow nonpremixed $CH_4-NH_3-N_2$/air flames at 1-3 bar have been conducted, and the results confirm the proper operation of the designed chamber.

Mechanical and acoustic behaviors of brine-saturated sandstone at elevated temperature

  • Huang, Yan-Hua;Yang, Sheng-Qi
    • Geomechanics and Engineering
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    • 제17권2호
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    • pp.215-225
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    • 2019
  • The mechanical behavior of rock is essential to estimate the capacity and long-term stability of $CO_2$ storage in deep saline aquifers. As the depth of reservoir increases, the pressure and temperature that applied on the rock increase. To answer the question of how the confining pressure and temperature influence the mechanical behavior of reservoir rock, triaxial compression experiments were carried out on brine-saturated sandstone at elevated temperature. The triaxial compressive strength of brine-saturated sandstone was observed to decrease with increasing testing temperature, and the temperature weakening effect in strength enhanced with the increase of confining pressure. Sandstone specimens showed single fracture failures under triaxial compression. Three typical regions around the main fracture were identified: fracture band, damaged zone and undamaged zone. A function was proposed to describe the evolution of acoustic emission count under loading. Finally, the mechanism of elevated temperature causing the reduction of strength of brine-saturated sandstone was discussed.

압력조건에서 공기로 희석된 프로판 확산화염의 매연 생성과 산화 특성 (Soot Formation and Oxidation in Air-Diluted Propane Diffusion Flames under Elevated Pressures)

  • 배승만;남연우;이원남
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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    • pp.267-268
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    • 2012
  • Soot formation and oxidation characteristics of air-diluted propane diffusion flames have been experimentally investigated under the elevated pressure conditions. PAH concentrations showed more pressure sensitive behavior comparing to soot volume fractions. The flame/soot temperatures in soot oxidation region were obtained using the MOLLIP technique. Under the complete soot oxidation environment, the flame/soot temperature is increased with pressure. The increased temperature could accelerate the soot oxidation process and then exothermic oxidation reaction, in turn, could further raise the flame/soot temperature, which would result in the enhancement of soot oxidation process.

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특발성 낭포성 중층 괴사 -1례 보고- (Idiopathic Cystic Medial Necrosis -A Case Report-)

  • 장병철
    • Journal of Chest Surgery
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    • 제12권3호
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    • pp.183-190
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    • 1979
  • A 23-year-old male patient complained dyspnea on exertion and orthopnea since December 1977. On examination, he was tall and slender. There was grade IV/VI to-and-fro murmur on the left sternal border especially on Erb`s point. The liver was descended 2 fingers breadth below right costal margin. There were no signs of Marfan`s syndrome. Echocardiography demonstrated partial closure of aortic valve and dilated aortic root with enlargement of ascending aorta. Left heart cardiac catheterization revealed moderately elevated pulmonary wedge pressure and right ventricular pressure. The left ventricular end diastolic pressure was markedly elevated to 26 mmHg. On aortography, the aortic regurgitation was severe and it was belonged to angiographically Grade IV. The aortic valve was replaced with Carpentier-Edwards valve without excision and replacement of ascending aorta, under the impression of rheumatic valvular heart disease. After closure of aortotomy, blood pressure was transiently elevated and bleeding from the site of inserting air vent needle of ascending aorta was developed. The bleeding was not controlled by any means. On postmortem microscopic study, the histologic changes were strikingly limited to the ascending aorta from the region of the aortic valve ring.

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다이아프램식 수소압축기의 캐비티 내 압력특성 변화에 관한 실험적 연구 (A Experimental Study on a Pressure Variation in the Cavity of Hydrogen Diaphragm Compressor)

  • 신영일;박현우;이영준;송주헌;장영준;전충환
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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    • pp.769-772
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    • 2009
  • Diaphragm compressors are used for a hydrogen compression because it can achieve high gas pressure with high purity. But diaphragm's lifetime may depend on the shape of the cavity and deflection from fluctuation the pressure change, which is necessary to monitored. In this study, the gas and hydraulic oil pressure in the cavity were measured as piston speed varies for diaphragm compressor. The results show pressure change quantities were reduced and maximum pressure points are delayed as the piston moves faster. And the hydraulic pressure were elevated as gas pressure elevated. And the compression period was more faster than expansion period.

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A Case Study on the Development of an Elevated Subsidence Inversion Over a Surface Low Pressure System

  • Kim, Kyung-Eak;Ko, Hye-Young;Heo, Bok-Haeng;Ha, Kyung-Ja
    • 한국지구과학회지
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    • 제31권5호
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    • pp.531-538
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    • 2010
  • This study presents the development of an elevated subsidence inversion over a surface low pressure system, which was formed along the Changma front or Meiu-Baiu front. The results of our analysis strongly suggest that the inversion is dissimilar to those formed in anticyclonic situations but is instead similar to the onion-shaped sounding found in wake low. The present analysis indicates that the observed elevated inversion resulted from the intrusion of stratospheric air associated with tropopause folding.