• 한국화재소방학회논문지
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• 제23권6호
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• pp.10-15
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• 2009

산불에서의 화염높이 산정은 복사열전달에 의한 수평 또는 수직적 화염확산을 예측하는데 있어 매우 중요한 부분이다. 화염특성 중 화염높이는 빛을 수반하는 화염(the luminous flame)의 평균높이로 확인할 수 있다. 본 연구에서는 외부 풍속과 경사 등으로 인한 화염 높이가 변화될 수 있는 조건을 제외한 산림내 지표연소물질(surface fuel)인 소나무 낙엽층(fuel bed)에 대한 화염높이 관측실험과 열량분석계을 이용하여 발열량(Heat Release Rate) 측정실험과 수치해석을 통해 지표연소물질에 대한 화염높이 산출식 $H_f=0.027(\dot{Q'})^{2/3}$을 도출하였다. 실험값과 개발 산정식, 기존 Heskestad 식과의 적용값 비교 결과, 소나무 낙엽의 경우, 실험값과 개발 산정식 적용값의 표준오차는 0.08, 실험값과 기존 Heskestad 식의 표준오차는 0.23으로 개발 산정식의 정확성이 높은 것으로 나타났다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제18권3호
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• pp.29-39
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• 2012

Window and shading designs have a great influence on energy consumption and daylighting in buildings. As far as energy is concerned, small window area is advantageous. But it is not good to the patient healing in hospital. So it is important to find out the optimum window shape which is favorable for both energy consumption and patient healing. In this study, annual energy consumption and daylight illumination levels were analyzed according to the window shapes and shading devices for a multi-beded patient room in hospitals. The simulations were conducted for 19 different cases by COMFEN 4.0 computer simulation program. The results of this paper are as follows. First, window to wall area ratio and shading devices have great influences on annual energy consumption. But it is a problem in that they decrease significantly daylight level in bed room. Second, considering the same energy consumption, reducing the width of window rather than the hight of window is desirable for the secure of daylight level. Third, increase of the number of horizontal shade is not desirable in south face of the building for the energy consumption and daylight level. Fourth, sun shade is not necessary in north face of the building for the energy consumption and daylight level.

• Journal of Biosystems Engineering
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• 제23권3호
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• pp.259-270
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• 1998

An automatic seedling transplanter, employed an innovative plug-seedling feeder was developed by improving the problems of conversational feeding and transplanting mechanisms. With conventional methods, missing and damage rates of seedling were high for long seedlings over 20cm and also breaking seed-bed was frequently observed. Thus, a pushout-bucket slide-hopper type trandsplanter was devised and tested. Test results of picking and transferring accuracies of the developed transplanter are as follows : A prototype transplanter performed with 1.5% of missing rate. The deviations of horizontal feed ranged from -0.3mm to 2.8mm and averaged 0.673mm for the 128-hoe test tray : and ranged from -lmm to ＋3mm and averaged 0.785mm for the 200-hole test tray. The deviations could decrease with precise manufacturing and lightening the mechanism. The maximum and deviations of vertical feed were -2.3mm and + 1mm, respectively, for the 128-hole test tray ; and were ＋3mm and ＋2.5mm, respectively, for the 200-hole test tray. The missing rate, seeding bruise rate and seed-bed damage rate were esitmate to be 1.3％, 0.4% and 3.5％, respectively, with the developed automatic transplanter.

• Journal of Advanced Marine Engineering and Technology
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• 제39권2호
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• pp.136-142
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• 2015

The shell and tube heat exchanger is an essential part of a power plant for recovering transfer heat between the feed water of a boiler and the wasted heat. The baffles are also an important element inside the heat exchanger. Internal materials influence the flow pattern in the bed. The influence of baffles in the velocity profiles was observed using a three-dimensional PIV (Particle Image Velocimetry) around baffles in a horizontal circular tube. The velocity of the particles was measured before the baffle and between them in the test tube. Results show that the velocity vectors near the front baffle flow along the vertical wall, and then concentrate on the upper opening of the front baffle. The velocity profiles circulate in the front and rear baffle. These profiles are related to the Reynolds number (Re) or the flow intensity. Velocity profiles at lower Re number showed complicated mixing to obtain the velocities and concentrate on the lower opening of the rear baffle as front wall. Numerical simulations were performed to investigate the effects of the baffle and obtain the velocity profiles between the two baffles. In this study, a commercial CFD package, Fluent 6.3.21 with the turbulent flow modeling, k-${\epsilon}$ are adopted. The path line and local axial velocities are calculated between two baffles using this program.

• 자원환경지질
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• 제12권1호
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• pp.1-12
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• 1979

A model study was conducted for the interpretation of simple geologic structures. Experiments were carried out for the cases of two horizontal beds and dipping beds in a water tank by using Wenner and Schlumberger arrays respectively. As a geologic stratum of experimental model, cement be (cement: sand=1:2) of $70cm{\times}60cm{\times}10cm$ was used. It was found out from a preliminary experiment that a measuring sounding of Wenner arrays is one third of the distance between two current electrodes, and Schlumberger arrays is one fourth of the distance which is a half of the value determined by usual method of calculation. Equi-resistivity curves were obtained for the cases of horizontal beds and dipping beds, and mapped on the longitudinal and cross sections of the water tank. These curves delineate the shape and degree of dip of bed to some extent. The calculation of depth to beds by using a master curve is somewhat complicated and inexact. In this study, new method for this calculation using a ${\rho}_a/{\rho}_1-a$ graph was proposed, and turned out that this method is simpler and exact.

• Computers and Concrete
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• 제23권2호
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• pp.97-106
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• 2019

This paper describes the design of a new interlocking masonry system, the production of designed interlocking units and mechanical properties of interlocked masonry assemblages with mortar. In this proposed system, units have horizontal and vertical locks to integrate the units to the wall and have a channel to enable the use of horizontal reinforcements in the wall. Using these units, unfilled, filled or reinforced walls can be constructed with or without mortar. In the production of the interlocking units, it was decided to use foamed concrete. 12 trial productions have been carried out at different mix proportions to obtain the optimum concrete mix. At the end of the mentioned productions, the units were produced with foam concrete which is selected as the most suitable in terms of compressive strength and specific gravity. Then, axial compression, diagonal tension and bed joint shear tests were carried out to determine the mechanical properties of the interlocked masonry assemblages with mortar. Results from the tests showed that interlocks designed to strengthen the system against shear stresses by creating discontinuity throughout the joints have been successful to achieve their aim. Obtained data will enable structural analysis of walls to be constructed with these new units.

• 한국습지학회지
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• 제16권2호
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• pp.261-268
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• 2014

본 연구의 목적은 직렬연결 2단 수직 및 수평 모래 갈대 인공습지에 생활하수를 간헐적으로 주입하였을 때 각 수질항목별 처리효율을 평가하는 것이다. 하수는 수리학적 부하량 $314L/m^2{\cdot}day$(수직 흐름 인공습지 기준)를 하루 4(10분 동안 주입후 5시간 50분 동안 중단)회 균등하게 간헐적으로 주입하였다. 평가 결과 pH는 유입수(7.27)보다 수직 흐름 인공습지 유출수(5.81)에서 감소하였다가 수평 흐름 인공습지 유출수(6.40)에서 다시 증가하였다. DO의 농도는 유입수에 비하여 유출수에서 높았으며 겨울로 갈수록 증가하였다. 수직 흐름 인공습지의 산소 전달율 (oxygen transfer rate: OTR)은 $58.72gO_2/m^2{\cdot}day$ 그리고 수평 흐름 인공습지의 OTR은 $7.72gO_2/m^2{\cdot}day$이었다. 각 항목별 평균 처리효율은 SS 94.80%, BOD 90.77%, $COD_{Cr}$ 85.87%, $COD_{Mn}$ 87.72%, T-N 64.74%, $NH_4{^+}$-N 86.44%, T-P 87.70%이었다. 유출수중 T-N의 반 정도는 $NO_3{^-}$-N(7.21 mg/L)이었으며 $NO_2{^-}$-N은 평균 0.64 mg/L이었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.400-403
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• 2004

In conventional methods, the availability of floating crane has determined the size of a concrete caisson. However, this paper introduces a new method for larger caisson production that make it possible to complete caisson fabrication and launch out without use of floating crane. The new method carries out multi-step fabrication of caisson and horizontal transfer of caisson on a single casting bed which consists of collapsible soffit form, trough, aero go watercaster system or low frictional PTFE added jacking system, half-submergible floating dock. To make the new method successfully launched, the static and dynamic analysis is carried out to obtain the stability of caisson launching and experimental research is conducted in evaluating friction occurred between PTFE pad and steel track. Lastly, the comparison of the new method and the conventional method are detailed. With significant benefits in construction costs reduction and construction time reduction, this new method in this paper would be recommended for extensive application in large port and harbor construction projects.

• Journal of Advanced Research in Ocean Engineering
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• 제2권1호
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• pp.40-47
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• 2016

This paper describes the design and performance of a hovering AUV constructed at KMOU (Korea Maritime and Ocean University). Before the field test, we analyzed the dynamic performance of the AUV using a simulation program made by Matlab & Simulink. Also, a PID controller was designed to control the thrusters. Using 4 thrusters (2 vertical and 2 horizontal), the AUV could be controlled using dynamic motion with 4-DOF. A simulation and field test were conducted with way-point tracking, maintaining the desired depth. To perform way-point tracking, the AUV can be fine-tuned to the desired heading angle through the LOS (Line Of Sight) method. This paper shows the results of simulation and field tests.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제1권1호
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• pp.69-78
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• 1995

This study is intended to understand the architectural characteristics and trends of general hospitals in Europe. The Observations, interviewes with the staff, and analyses of related materials were executed through the study-visits of sample hospitals. Some results of the study could be summarized as follows : (1) The architectural characteristics of sample hospitals could be described as the realization of horizontal design concept, application of urban design method, specialization of service departments, intergration of facility design, and planning for the emergency & disaster. (2) The architectural trends of sample hospitals could be suggested as the decentralization of functions, promotion of building standard, enhancement of interior space, consideration of environment, and autonomous management & operation of facilities. (3) The humanistic and environmental approaches from european hospitals would be preferably applicable rather than the popular concept of automation, ultra-modernization and mega-structure in Korea. First of all, the bed-center and proper facilities for disaster should be considered.