• Journal of Advanced Marine Engineering and Technology
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• 제36권4호
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• pp.445-450
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• 2012

가정과 같이 제한된 공간에서는 공조기의 온습도 조절이 어려워 질 수 있다. 최근에 들어서 사람들의 온습도에 대한 감성이 민감해 짐에 따라 실내 공기질에 대한 중요성이 부각되고 있다. 실내 공기질과 에너지 절약 사이의 모순을 해결 할 수 있는 방법으로 환기열회수장치를 제시하고 이러한 환기열회수 장치에 열전소자를 적용하여 온도 효율을 비교하고 시스템 능력을 검증해 보았다. 온도효율을 향상시키는데 전도성 가이드 베인과 단일 모터, 열전소자가 실험되었다. 단일 모터 사용시 23W를 절약 할 수 있었고 250 CMH의 능력을 가지는 개발된 시스템에서 통상적인 시스템과 비교해 냉방 주기 및 난방 주기에서 각각 4.01% 와 2.98%의 개선이 있었다.

• 설비공학논문집
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• 제20권8호
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• pp.526-533
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• 2008

In this study, theoretical super screen vibration analysis has been carried out to predict the dynamic characteristics of interactive waste particles. In order to approach these problems, it is necessary to have a fundamental understanding the screening process and the process of both the remaining and the passed material on a screen with several interacting screen planes based on Soldinger(1999) was discussed. Here, the vibrating screen is composed of three assemblies such as screen, wastes guide, and supported screen as shown in Fig. 1. This model is regarded vibrator as the system of screen fixed tilt plates. Then materials(or particles) of different size is to be separated by using the eccentric vibrator and classifying tilt plates. As well moisturized construction wastes is more efficient to separate than moisture-less it. In processing separate mechanism, the more materials is light, the more staying time is long. Thus much lighter construction wastes(wood, Styrofoam, etc) and heavier materials are separated by staying time delay in a super screen. The design results, separation screen were able to know that small and larger particles are conspicuous difference each motion character according to trajectory particles, and small particles raise the probability in classifying tilt plates.

• 설비공학논문집
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• 제18권12호
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• pp.1007-1016
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• 2006

Although the advance in electronic technology enables a large number of circuity to be packed in a small volume, it is simultaneously required to remove the high heat load produced by them. In this study, the heat transfer and pressure drop characteristics of a mini-channel heat exchanger, which is designed for liquid cooling of electronic components, are investigated by varying operating conditions. Water and FC-72 were used as working fluids. The mini-channel heat exchanger was made with circular shape channels having din-meters of 2, 3, and 4 mm in regular intervals, and the channel length was 100 mm. The header and inlet guide pathway to provide uniform inflow were attached at the inlet of the test section. Copper block including the heaters was attached at the sidewall of the test section as a heat source, which provided the heat flux from 5 to $15W/cm^2$. The entrance effects enhanced the heat transfer coefficient in the mini-channel significantly. In addition, the single-phase pressure drop in the mini-channel was very similar to that predicted by the laminar flow correlation except that the transition Re decreased due to flow instability in the entrance region.

• 한국산학기술학회논문지
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• 제12권11호
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• pp.5384-5391
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• 2011

본 논문에서는 RCO 반응기의 최적 조업 조건을 도출하고자 현재 조업 중인 RTO 반응기 촉매층의 압력분포, 유속분포, 유선장, 체류시간, 온도분포 등에 대하여 분석하였고 최적의 조업 조건을 도출하기 위한 전산유체해석을 수행하였다. 전산 해석 결과, 현재 조업중인 반응기 촉매층의 축열재로 인한 압력손실은 크지 않은 것으로 나타났으며, 세라믹 필터 이후 유속은 1.8~2.7 m/s로 특별한 편류없이 비교적 안정적 유속분포를 보이고 있었다. 기류분포를 좀 더 개선하려고 한다면 설비 내부에 플래넘과 촉매층 접속 구간 연장 등의 방법을 고려할 수 있을 것으로 판단된다. 그러나 기류 안내판이나 다공판 부착 등의 방법은 큰 효과는 없을 것으로 나타났다.

• 한국축산식품학회지
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• 제39권2호
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• pp.209-221
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• 2019

In this study, the changes in microbial communities of lamb meat packaged in the air (plastic tray, PT) and in a vacuum pouch (VAC) were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) during the storage at $4^{\circ}C$. For the PT lamb, the total viable count (TVC) was $10^7CFU/g$ on Day 5, and the dominated bacteria were Pseudomonas fragi, P. fluorescens, and Acinetobacter spp. For the VAC lamb, the TVC was $10^7CFU/g$ on Day 9, and the dominated bacteria were lactic acid bacteria, including Carnobacterium divergens, C. maltaromaticum, and Lactococcus piscium. One strain of Pseudomonas spp. also appeared in VAC lamb. The relative abundance of Enterobacteriaceae in VAC lamb was higher than that PT lamb, indicating a more important role of Enterobacteriaceae in spoilage for VAC lamb than that of PT lamb. The microbial compositions changed faster in the lamb stored in a PT than that stored in a VAC, and microbial community compositions of the late storage period were largely different from those of the early storage period for both the conditions. The findings of this study may guide improve the lamb hygiene and prolong the shelf life of the lamb.

• 한국인터넷방송통신학회논문지
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• 제22권1호
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• pp.21-27
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• 2022

사회가 발전하고 복잡해짐에 따라 재난의 종류도 미세먼지, 전염병 등과 같이 새롭고 다양하게 발생하고 있다. 하지만 기존에는 이러한 재난에 대비할 수 있는 정확한 정보를 제공하는 전관방송 시스템이 없었다. 본 논문에서는 공공 데이터와 IoT 센서로부터 수집된 오염된 대기질 데이터를 분석하여 자동으로 경보를 방송하는 전관방송 시스템을 제안한다. 대기질에 따라 경보의 단계가 달라지며, 공공데이터에서 제공하는 정보는 측정소로부터의 거리나 풍향 등 다양한 요인으로 인해 안내 지역과 상당한 차이가 있는 결과를 나타내기도 한다. 이를 보완하기 위해 공공데이터에서 가져온 데이터와 현장 IoT센서에서 얻은 데이터를 비교 분석하여 방송하는 방법을 제안하고자 한다.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.615-630
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• 2002

Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

• 한국전산유체공학회지
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• 제13권4호
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• pp.72-79
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• 2008

This study is to investigate the air flow around a sirocco fan which is used in a range hood. The main object of the study is to improve the flow rate of the fan by analysis of unsteady 3-dimensional incompressible flow. Overall analysis is carried out using CFD method. For this, we used a commercial code, SC/Tetra, and used a sliding mesh method to give the same condition as an actual state. First, verification of the CFD results is done by comparing the experimental data with the numerical data for the suction flow rate. It is confirmed that two results are well consistent. Then for the improvent of flow rate, the effect of shape factors such as diameter ratio of fan, geometry of case, cut-off aperture and guide angle of case exit on the suction flow rate was considered. Especially, for a new design of housing, the principle of Archimedes spiral was used. The overall analysis was applied to a new design of housing, and the result showed an increase of flow rate by 10.7%.

• 한국화재소방학회논문지
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• 제15권4호
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• pp.49-56
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• 2001

화재시 특별피난계단의 부속실의 연기침입을 방지하기 위해 적용하고 있는 급기가압방연시스템의 효능에 대한 논란이 증가하고 있는 바, 국내 고층 건축물의 특별피난계단에 설치운용중인 급기가압시스템의 설계시 핵심요소인 가압공간의 누설틈새, 계단실과 부속실 또는 부속실과 거실공간사이의 출입문을 통한 방연풍속과 출입문의 자동폐쇄를 보장하는 도어 개폐장치등에 대한 문제점을 조사연구하여 실질적인 효과를 보장할 수 있는 기준을 설정하고, 안전성확보를 보장하면서 경제성을 고려한 설계안을 세부적인 사례를 들어 구체적으로 제시하였다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.107.1-107
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• 2003

The fermentation process and subsequent processing determine the efficacy of a bioherbicide propagule. Large batches of biomass of the mycoherbicide agent for white clover, Sclerotium sp.(BWC98-105) was produced in simple liquid fermentator in 5 gallons vessels(Model No. 8087, Dabo Inc., Korea) with oxygen supply(DPH16000, FineTech Inc., Korea) simulating industrial conditions by utilizing commercially available, inexpensive ingredients (10 ％ rice bran), The maximum biomass yield of Sclerotium sp.(BWC98-105) was obtained after 5 days of air pumped incubation at room temperature condition(22-28$^{\circ}C$). By using this simple facility, it could get fragmented or proliferated greatly and attained maximum mycelia biomass. The biomass of mycoherbicide agent consisted of hyphae devoid of spores. Biomass mycelia of the fungus 99％ survival at room temperature after 2 me. A thorough understanding of the effects of fermentation and formulation on viability and virulence is required to guide these processes. After an economical yield level of bioherbicide propagule has been achieved in a fermentation process, formulation becomes a critical factor which influences product efficacy. Because the fermentation must be stopped at a point when virulence/viability are optimum, the live bioherbicide propagule must be stabilized, formulated, and packaged.