This study improved the work efficiency by supplementing the shortcomings of the manual process by developing a double tube feeding device, and the following results were obtained by conducting the production capacity, production length, and defect rate tests. Developed a double tube production system to enable the simultaneous production of two tubes, increasing the production volume by about 1.5 times. The product length has been improved from semi-automatic to automated, and the production capacity has been improved from 16 to 25 pieces per hour (based on 15m). Developed a double-tube input straight line automatic adjustment feeder, which resulted in reducing the defect rate to less than 1%.
In general, small and medium-sized computer rooms do not have access floors for reasons of increased floor height and increased construction cost. Therefore, the air conditioning method used here applies the method of directly blowing the cold air of the air conditioner into the computer room. In this case, the hot/cold air is not separated, and as the hot air is recirculated, it is re-introduced to the front of the server rack, resulting in a problem that the server cooling efficiency is decreased. In addition, in such a computer room structure, it is difficult to configure and install a containment system. In this study, we tried to understand the problem of the formation airflow in the case of using the existing air conditioning method, and to find a method of configuring the air conditioning environment to improve the cooling efficiency. The purpose of this study was to understand the airflow/temperature distribution in the computer room using the CFD simulation method. In addition, the thermal characteristics of various air-conditioning environments such as the location of the CRAC cold air discharge location, the layout between server rack and CRAC and the containment were reviewed.
To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.
This experiment evaluated the efficiency of mechanical ventilation, one of the measures to reduce indoor radon concentration in residential spaces. In the most popular ventilation rates of the air conditioning system, the most efficient air conditioning system was confirmed by checking the time when the radon concentration reached the lowest level, the radon reduction rate, and the radon concentration that could be lowered as much as possible. The results showed a reduction rate of up to 80% or more as a result of conducting the experiment by blocking the inflow of outside air. It was confirmed that the time to reach the lowest concentration after starting the mechanical ventilation was about 6 hours to a maximum of 7 hours. Therefore, this study verified that indoor radon concentrations can be efficiently reduced by using a mechanical ventilation system.
In this study, heat exchangers used in data center and building air-conditioners were tested according to the type of heat exchangers to select them for commercial use. The experiment was performed three samples, one micro channel heat exchanger, the same volume oval coil and the same performance oval coil. The experiment conducted under actual operation conditions in the data center and building. Micro-channel heat exchanger has lower air side pressure drop and higher capacity per volume than oval coil. It may be advantageous when the installation small space or the little design static pressure in the fan, such as in-row systems or CRAC installed in data center.
목적 : 본 연구는 인공눈물과 습윤액에 대한 일반인의 올바른 사용법 인지 여부의 파악하고, 인공눈물 및 습윤 액 사용 시 시간 경과에 따라 눈물막 안정성(눈물띠 높이와 눈물막 파괴시간)에 미치는 영향을 측정하고자 하였다.
방법 : 첫 번째 실험은 온라인 설문조사로 안구점안액의 사용법에 대한 인지를 온라인 설문을 통하여 실시하였다. 두 번째 실험은 20명의 피실험자를 모집하여, OSDI 점수를 기준으로 건성안과 비건성안 그룹으로 나누고(건성안 그룹 10명, 비건성안 그룹 10명), 참가자에게 3개의 점안액(인공눈물(AT), 습윤액(CS), 식염수(SS)를 점안하도록 하였다. 점안 후 1분, 3분, 5분 단위로 눈물막 높이(TMH)와 눈물막 파괴 시간(TBUT)을 측정하여 눈물막 안 정성 변화를 확인하였다.
결과 : 127명의 온라인 설문 응답자 중 66.6%(N=82)가 인공눈물과 습윤액의 차이에 대해서 잘 모른다고 응답하였으며, 콘택트렌즈 착용자 중 68.1%(N=47)는 렌즈 착용 중 인공눈물을 점안한 경험이 있다고 답하였다. 점안 시 시간경과에 따라 눈물띠 높이는 통계적 유의성이 있었다.(Baseline<1 min and 3 min, p<0.050). 하지만 점안전과 5분경과시의 눈물띠의 차이는 없었다(p=0.720). 눈물막 파괴시간은 점안액 종류별로 유의적인 차이가 있었으며 (SS<AT, CS p<0.050) 시 간경과에 따른 유의적 차이도 있었다(baseline, 5 min after < 1 min after, p<0.050).
결론 : 많은 사람들이 올바른 사용법에 대한 인지가 부족하였으며, 올바른 사용법의 전달이 이루어져야 할 것 이다. 눈물띠 높이는 점안액에 따른 변화는 5분 이후에는 관찰되지 않았으며, 이는 일시적인 증상완화만을 의미할 수 있다. 눈물막 파괴시간은 인공눈물을 점안 시 1분경과시 가장 길게 나타났다. 식염수 점안 시 눈물막이 가장 불안정하게 되었으며, 특히나 눈물막 파괴시간에 미치는 영향이 가장 컸다.
Indirect evaporative coolers (IECs) are widely used for cooling of outdoor air in building air-conditioning and for cooling of indoor air in data center air-conditioning. However, for each case, the inlet air temperature and humidity condition to IEC are different, which may yield different cooling efficiency. In this study, tests were conducted at the two air conditions using two IEC samples having different channel pitch (3 mm × 5 mm, 5 mm × 5 mm). Results showed that the efficiencies of the 3 mm × 5 mm sample were 12~32% larger than those of the 5 mm × 5 mm sample due to 25% larger heat transfer area and the usage of smaller diameter channel. The efficiency was 10% larger at the data center condition than at the building condition. The reason may be attributed to a larger absolute humidity difference between the liquid film and the air at the data center condition. At the same air velocity, the pressure drops at the wet channel were 64~128% larger than those at the dry channel due to the presence of liquid film at the wet channel. Comparison of the data with predictions by the analytical model revealed that both the efficiency and the pressure drop were over-predicted. Possible reason may be the simplification of the channel geometry and the assumption of fully developed flow, which may be improved in the future.
To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.
굴 패각과 같은 반응성 재료는 사용 목적에 적합한 전처리 조건을 선택할 필요가 있다. 본 연구에서는 인 농도 제어를 목적으로 효율적인 굴 패각 사용을 위한 전처리 조건을 제안하는데 목적을 둔다. 굴 패각의 전처리(소성 온도, 소성 시간, 입자 크기)에 따른 인산염 제거 효율을 조사하였다. 또한 XAFS 분석 및 등온 흡착 실험을 통해 굴 패각의 인산염 제거특성에 대해 조사하였다. 실험 결과 소성 온도는 600°C, 소성 시간은 6 h, 입자 크기는 0.355~0.075 mm에서 우수한 제거 효율을 확인하였다. 등온 흡착 실험 결과 Langmuir 모델이 굴 패각의 흡착에 적합한 것으로 나타났다. XAFS 분석 결과 600°C에서 소성시킨 굴 패각에는 인산칼슘이 생성된 것이 확인되었다. 즉 굴 패각의 칼슘 이온 용출에 의한 인산칼슘 형성이 인산염의 농도 감소에 기여하고 있음을 확인하였다.
본 연구는 냉동공조용 열교환기 내 스케일 형성으로 열전달 과정에서 열저항으로 작용하여 냉동공조시스템의 냉각성능이 떨어져 이를 해결하기 위해 전기분해 원리를 이용하여 배관 내 스케일을 자동 제거하는 시스템을 개발하여 그 성능을 실험을 통해 확인하고자 한다. 이전까지는 배관 내 스케일을 2∼3 년에 한번씩 브러시나 분사 노즐에 의해 기계적으로 배관 내를 청소를 하거나 화학약품을 이용하여 세관하였다. 이러한 세관은 시간이 경과하면 또 관이 오염되어 전열성능이 떨어지고 냉각장치의 운전을 정지하여 반복해야하는 여러 가지 문제점을 안고 있었다. 따라서 시스템의 정지없이 전기분해 원리를 이용하여 만들어진 처리수를 순환시킴으로서 스케일의 원인물질은 Ca, Mg, SiO2를 고형물 형태로 석출시켜 배관계 외부로 배출시킴으로서 배관내 스케일 발생을 차단하고 기 형성된 스케일을 제거하여 배관의 전열 성능을 유지하고자 하는 것이다. 실험한 결과, 새 배관의 열전달율을 100으로 기준할 경우, 스케일이 형성된 배관의 열전달율은 86.66%이었으며, 스케일이 형성된 배관을 1개월 동안 처리수를 가동했을 경우 열전달율은 90.5%의 수준까지 회복되었으며, 2개월간 운전한 경우 97.86%의 수준까지, 3개월 운전했을 경우 98.72% 까지 열전달율이 회복되었다. 비교적 짧은 실험기간이지만 배관내 형성된 스케일의 제거효과를 파악하였으며, 전열성능에도 영향을 미치고 있음을 확인하였다.
This study investigated the odor-associated bacterial community in automobile HVAC systems. Through a metagenome analysis, it was found that; Massilia (42.426%), Sphingomonas (28.200%), (10.780%), and Methylobacterium (5.756%) were abundant in the HVAC systems. Massilia can cause the biodegradation of polycyclic aromatic hydrocarbons (PAHs) producing odor in automobiles. Sphingomonas produces volatile halogenated compounds or degrades organic pollutants. Rhodococcus is reported to produce sulfur compounds which give off an odor similar to rotting eggs and cabbages. Methylobacterium is one of the most representative bacteria that causes odor in automobile HVAC systems. The evaporator is considered as the appropriate habitat for microorganisms in automobiles because of its high humidity and organic adsorption. Massilia, Sphingomonas, Rhodococcus, Methylobacterium, Bacillus, Staphylococcus, Arthrobacter, Micrococcus, and Pseudomonas, listed in order from most to least present, were isolated as abundant bacteria in the evaporator of the HVAC systems.
In this paper, we utilize a Gaussian process to predict the power consumption in the air-conditioning system. As the power consumption in the air-conditioning system takes a form of a time-series and the prediction of the power consumption becomes very important from the perspective of the efficient energy management, it is worth to investigate the time-series model for the prediction of the power consumption. To this end, we apply the Gaussian process to predict the power consumption, in which the Gaussian process provides a prior probability to every possible function and higher probabilities are given to functions that are more likely consistent with the empirical data. We also discuss how to estimate the hyper-parameters, which are parameters in the covariance function of the Gaussian process model. We estimated the hyper-parameters with two different methods (marginal likelihood and leave-one-out cross validation) and obtained a model that pertinently describes the data and the results are more or less independent of the estimation method of hyper-parameters. We validated the prediction results by the error analysis of the mean relative error and the mean absolute error. The mean relative error analysis showed that about 3.4% of the predicted value came from the error, and the mean absolute error analysis confirmed that the error in within the standard deviation of the predicted value. We also adopt the non-parametric Wilcoxon’s sign-rank test to assess the fitness of the proposed model and found that the null hypothesis of uniformity was accepted under the significance level of 5%. These results can be applied to a more elaborate control of the power consumption in the air-conditioning system.
In this study, by comparing the heating performance when operating the air conditioning system that is installed directly air-cooled(heater) air conditioning central air conditioning system of the ship, with improved performance, through the actual measurement study of thermal environment of the cabin, Ship's air conditioning in the future it is intended to be used as a basic data experience of design and planning.
In this study, to develop high-efficiency environmental improvement system that can be combined with hot and cold potable water supply to poultry air conditioning for the summer increase heat stress relief and winter feed efficiency through optimal design hwihan The aim of this study was to provide basic data. As a cage the size of the system installed is 100m2 test capacity 20RT district heating and cooling of air-to-water heat pump and the control was composed of electric hot water boilers. First of cage sizes for heating load design, materials, heat pump capacity, air capacity, storage tank, drinking water tank capacity, etc. were determined. The capacity of the heat pump was set to 20RT cage captive birds are erected as vertically and horizontally × height × (13 × 21 × 4.5m). Storage tank 3 tons and capacity of 10 tons potable water tank was designed. In the future, the size of the cage, designed according to the best breeding two numbers are needed.
It is important to understand psychological and physiological responses of occupants who seated in a chair in order to shape a comfortable indoor official environment. So it is needed to find out optimal seated conditions. The purpose of this study was to explore optimal condition of seat air conditioning control based on psychological or subjective responses (perceived temperature and comfort sensation) and physiological responses (heartrate variability; HRV). To do this, experimental conditions were designed by the difference of indoor temperature and seat air conditioning temperature. In the experiment 1, seven experimental conditions were designed with one control condition which was not used seat air conditioning system, and six experimental conditions which the difference of indoor temperature and seat air conditioning temperature (-1℃~-6℃). In the experiment 2, four experimental conditions were designed with one control condition and three experimental conditions (-3℃~-5℃). In addition, participants’ psychological or subjective response was measured by CSV (comfort sensation vote) and PTS (perceived temperature sensitivity) as a psychological or subjective response, and heartrate variability was measured as a physiological response. As a result, in the experiment 1, it was reported that the optimal conditions of seat air conditioning control based on participants’ psychological or subjective comfort were from -3℃ to -5℃ experimental conditions. In addition, in the experiment 2, it was reported that the optimal condition of seat air conditioning control based on participants’ physiological comfort was -4℃ experimental condition. These results suggested that seat air conditioning could affected to comfort sensation of occupants in an appropriate range, rather than unconditionally.
For many brands, offering valuable and original experiences for customers is the main means of gaining awareness, image values and hence, strategic competitive advantage. Brands like Abercrombie and Fitch, BONOBOS and Victoria’s Secret have understood the opportunities offered by experiential marketing as a new philosophy of thinking, conceiving and proposing a marketing offer. This challenge is as important for online fashion brands that target millennial customers considered as internet addicts (Bergman et al., 2005) always looking for information, exhibitionism and enjoyable online experiences. With the growth of online fashion shopping it is important that fashion retailers pay attention to the relationship between specific website quality dimensions and customer satisfaction (Kim and Stoel, 2004). Fashion brands must go beyond the vision of the website as a medium of information to a medium of entertaining proposing additional extraordinary and optimal experiences for these customers. As noted by Kim (2007), online fashion retailers need to be able to communicate the product information virtually in order to create accurate product perceptions for consumers who are visiting their website. Thus, the main question is “what are the elements of the website which could help achieve these aims?”
There has been little empirical research which focuses on how information features affect consumers` commitments to a shopping site on the web (Park and Kim, 2006). Consequently,the main aim of this paper is to further research in the domain by illustrating how the online fashion brand provides a valuable shopping, consuming and cognitive experience that fits with the consumer’s expectations aligning these with the extraordinary and symbolic world of the brand. From this perspective, the website of the brand – due to its multisensory, interactive and hyper-mediatized nature – can be a very effective digital support for achieving these goals. It represents the virtual environment that enables the brand to create and open up a universe that transcribes its functional, experiential and symbolic values. From the consumer’s psychological perspective, this online communication strategy questions the psychological process that underlines the perception, elaboration and reactions of the consumer during his online experience: To this is end, it is relevant to focus on the influences of the usability of the website on the attributes of the mental images the consumer experiences and the moderating role that brand attitude and involvement in the product category could have in this. Also, based on MacInnis and Price (1987) recommendations, it is relevant to analyze the role the consumer’s style of processing could have in this process. Thus, the research questions are: How do the attributes of the website impact the mental imagery experience of the consumer during his/her website visit?; and what are the consequences of these psychological reactions on the consumer’s post-visit attitude and behavior.
In attempt to respond to these questions, we explore the psychological process that underlies consumer online behavior. We draw on the literature which emphasizes the link between the website attributes and the imagery processing of the online consumer. We present and empirically test our conceptual model within the current quantitative study. We follow with a discussion of our results and presentation of the implications of our study for theory and practice.
분산된 유전입자를 가지는 OLED는 입자의 표면 상태에 의하여 새로운 부가적인 결과를 나타내게 된다. 본 논문에서는 유전입자가 분산된 Polyfluorene (PFO) 발광 층과 두 개의 전극을 가지는 간단한 구조의 PFO-base OLED를 제작하고 분산된 나노입자들이 분산을 위한 제작공정에서 필수적으로 발생하는 표면상태변화가 소자에 어떠한 영향을 미치는지 알아보았다. Spin-coating 공법으로 제작된 PFO-base OLED는 극소량 첨가된 유전입자의 고른 분산을 위한 공정이 필요하며 이 공정으로 인해 입자의 표면에서 scratch 가 증가 하고 , 또한 입자의 분쇄가 이루어 지기도 한다. 교반 시간의 증가는 표면 scratch와 입자의 분쇄를 증가시키게 되고, 이는 입자크기의 감소와 분쇄된 입 자끼리의 응집을 증가시켜 소자의 electrical conditioning을 변화시켰고 나아가 발광 특성에 영향을 주었다. 실험 결과 9시간 정도의 교반시간에서 입자의 표면전하로 인해 electrical conditioning이 개선되고 이로서 소자의 발광휘도가 최대 2.5배 이상 증가하였다. 반면에 교반시간이 증가하면 소자의 전반적인 휘도는 다소 감소하는 결과를 나타내었다. 이는 표면전하 증가와 함께 분산이 고르게 되지 않기 때문인 것으로 생각된다.