본 연구는 최적의 냉해동 조건을 확립하고 설정된 조건에 따라 냉해동이 당근에 미치는 이화학적 분석 및 영양성분의 분석을 진행하였다. 본 실험에서는 강제송풍방식을이용하였으며, 자연대류식(0.2oC/min), 저속(0.4oC/min) 및고속(1.6oC/min)으로 냉동속도를 조절하여 -12oC까지 냉동하였다. 해동조건은 전자레인지를 이용하여 0, 200, 400,800W의 세기로 출력을 조절하여 시료의 중심부 온도가4oC가 될 때까지 해동하여 분석에 사용하였다. 당근의 강도는 냉해동 후 유의적으로 감소하는 경향을 보였으며, 특히 200, 400W 해동 시 냉동 속도가 빠를수록 감소하였다.해동감량의 경우 해동방법에 따른 유의적인 차이는 없었지만 냉동속도가 높을수록 감소하는 경향을 보였다. pH 및색도의 데치기 후 당근과 처리구간의 유의적인 차이는 보이지 않았다. 그러나 전자 현미경 관찰 결과, 냉동속도가빨라질수록 기공의 크기가 작아지는 것을 확인할 수 있었으며 이는 빠른 냉동속도가 식품 조직의 손상을 막는데 영향을 미친다는 것으로 보인다. 비타민 C 및 유기산(oxalicacid, malic acid 및 fumaric acid) 함량의 경우 유의적인차이는 나타나지 않았다. 유리당 함량의 경우에는 sucrose함량은 자연대류 냉동 시 가장 높았고, fructose 및 glucose의 함량은 유의적인 차이가 없었다. 본 연구 결과 냉해동방법에 따른 영양학적 변화는 대부분 데치기 후 당근과 유사하였으나, 당근을 고속으로 냉동할 시 물리적 변화 및조직 손상을 최소화 하였으므로 당근의 품질을 유지하는데효과적인 것으로 판단된다.

The coating of solid lubricant on the part of fixed or orbiting scroll wrap in a scroll compressor can not only reduce friction loss, noise & vibration and time cost for surface finishing but also improve efficiency and performance of the compressor. In this study, we found the most appropriate combination of the solid lubricant by carrying out many measurements and tests such as coefficient of friction, surface structure, the coating thickness and surface roughness for the various cases. We have come to conclusion that the most appropriate solid lubricant can be obtained by adding WS2 3% to Base(SM 3901) without any solvent and filler.

The recent rise in SARS and bird flu infections around the world has raised the interest in studying the habits of air borne pathogens such as germs and viruses. In this study, simulations were carried out to predict the performance of UVGI air sterilizer at preventing airborne infections inside a car, based on the installation position and the removing effect of the UVGI air sterilizer. Simulation results showed that the UVGI air sterilizer was most effective when located at the rear side of the front seats. It was also showed that when the out-air mode and the UVGI air sterilizer were set to the highest capacity, the microbial safety levels were maintained in a car for 21 hours.

Most systems used in industrial sites, actually have non-linearity and uncertainty. Therefore there are a lot of difficulties in evaluating conditions of these systems. Generally, the quantitative analysis and expression are found hard because the general public cannot easily make an accurate interpretation on the systems. Thus development of a system that utilizes an expertise from skilled analysts is required. In this research, a real-time sensor signal conditioning system and Fuzzy-expert system have been separately set up into an inference algorithm. So that it ensures a fast, accurate, objective and quantitative operational condition value provided to the manager. Therefore, FE_AFCDM is suggested in this literature, as an effective system for diagnosing the problems related to the air compressor. It can quantify the uncertain and absurd condition to operate the air compressor facilities safely and financially.

The object of this study is to investigate the relationship between the air dilution sensory test and the threshold odor number (TON) method for evaluating the odor of domestic wastewater, plating plant wastewater, food plant wastewater and lake water. The dilution factor of raw wastewater evaluated by the air dilution sensory test was in the order of food plant > plating plant > domestic > lake, and that evaluated by the threshold odor number method was in the order of food plant > domestic > plating plant > lake. The same results were obtained when the raw wastewater and lake water were diluted 2 and 5 times with pure water. The relative geometric standard deviation determined from the threshold values of each panel on the air dilution sensory test was much larger than that calculated from results derived from the threshold odor number method. The relative geometric standard deviation obtained from samples with a low dilution factor was greater. There was a very good linear correlation (correlation coefficient = 0.968~1.000) between the air dilution sensory test and the threshold odor number method. But, the reduction in odor intensity (the slopes of regression curves) by dilution was dependent on the types of the odor-emission sources.

This study tried to survey air quality inside and outside the schools where are located in about 5km of industrial complex targeting aldehyde, PM10, PM2.5. Also, the aim was also to examine both a change in indoor air after 3 years and within 3 years of addition and improvement, and a change according to season. It collected specimens at totally 20 places. Aldehyde was analyzed through HPLC. PM10 and PM2.5 were measured by using Met One 831. Formaldehyde and Acetaldehyde were detected with 42.1 μg/m3 and 5.7 μg/m3 at the school where is located inside 5km of the industrial complex, and were detected with 55.0 μg/m3 and 6.8 μg/m3 at the school where is located outside 5 km. This could be confirmed to have been detected more highly in the indoor air than the outdoor air regardless of the distance from the industrial complex. Most substances were indicated to be higher by about 150% in the indoor air within 3 years than the indoor air following 3 years of addition and improvement. However, PM10 and PM2.5 were measured with 32.6 μg/m3 and 14.9 μg/m3 after 3 years and were gauged with 22.4 μg/m3 and 14.2 μg/m3 within 3 years. Seeing a seasonal change, Formaldehyde and Propionaldehyde were detected with 5.5 μg/m3 and 1.0 μg/m3 in spring, 7.7 μg/m3 and 1.6 μg/m3 in summer, and 8.3 μg/m3 and 1.9 μg/m3 in autumn. This could be confirmed the tendency of growing according to season.

Hazardous air pollutants such as NO2, VOCs and PM10 were measured Daegu, Korea in major micro-environments,where housewives spend the most of their time, and personal exposure times were estimated by using time activitypatterns and exposure scenarios. The major microenvironments of housewives were selected using the ‘Time-UseSurvey’ conducted by the National Statistical Office in Korea in 2009. A total of 4,514 (weekdays) and 3,063(weekends) housewives were recruited for the ‘Time-Use Survey.’ It seems that housewives are spending about80% of their time in the house, and about 5% of their time outdoors during weekdays and weekends. The indoor/outdoor ratio of the average concentration of NO2 was more than 1, which indicated that the source was indoors.Toluene was shown to have higher concentrations indoors than outdoors. Ethylbenzene and xylene displayedsimilar characteristics to toluene, and the concentration ratio for indoor/outdoor was shown to be 1.29 ± 0.76 and1.04 ± 0.45, respectively, higher concentrations indoors. Based on the results of the time activity patterns ofparticipants, 3 kinds of exposure scenarios were formulated. The spent time and air concentration in eachenvironment were assumed as normal and lognormal distribution, respectively. And then the Monte-Carlosimulation was conducted. According to the result of the simulation, the exposures to hazardous air pollutantsrevealed an increasing pattern as housewives visits other indoor environments such as supermarkets.

본 연구는 에어제트텍스쳐링 장치에서 공급되는 코어사와 이펙트사인 아라미드와 나일론의 구성이 방호의류 용 아라미드/나일론 ATY와 아라미드 ATY의 물성변화에 대한 연구이다. 아라미드 필라멘트 표면의 매끄러움 때 문에 아라미드 ATY의 강도 저하는 나일론 ATY에 비해 훨씬 높았다. 아라미드/나일론 ATY 강도는 ATY의 이펙 트사인 나일론의 강도에 가장 영향을 많이 받았다. 나일론 ATY의 절단신도는 에어제트텍스쳐링 이전의 나일론 에 비해 두 배정도 높은 값을 나타내었으며, 아라미드 ATY와 아라미드/나일론 ATY는 에어제트텍스쳐링 이전에 비해 5.9~6.7배 정도로 높았다. 아라미드 ATY의 초기탄성률은 아라미드의 에어제트텍스쳐링 이전에 비해 86.5% 정도 감소하였으며, 아라미드/나일론 ATY의 초기탄성률은 아라미드 ATY와 나일론 ATY 초기탄성률의 산술평균치를 나타내었다. 아라미드/나일론 하이브리드 ATY의 습․건열 수축률은 나일론의 영향을 받음을 알 수 있었다.

The main object of this study is to investigate the collection characteristics of wet-type rotating porous disk system experimentally. The experiment is carried out to analyze the pressure drop and collection efficiency for the present system with the experimental parameters such as system inlet velocity, stage number, tube diameter, inlet concentration, etc. In results, for the present system, at 5 stage and υin=1.8 m/s, the pressure drop becomes significantly lower as 64 mmH2O in comparison with that of the conventional wet type scrubber (Venturi scrubber, over 250 mmH2O). The collection efficiencies increase with higher inlet velocity showing 92, 95.7, 98.4%, while SO2 removal efficiencies decrease with increment of inlet velocity as 80, 65, 50% at υin=1.08, 1.44, 1.8 m/s and tube diameter Dt=10 mm, respectively. The present system is to be considered as an effective compact system for a simultaneous removal of particle/gas phase pollutants from marine diesel engines.

본 연구는 밀기울을 초미분쇄기와 공기분급을 동시에 수행하는 설비를 사용하여 분쇄기 회전속도 3,800, 4,800, 5,800 rpm, 분리기 회전속도 2,500, 3,000, 3,500 rpm으로 분쇄하고, 공기분급기 회전속도 200, 400, 600 rpm으로 분쇄된 밀기울을 공기분급한 각 분급물의 특성을 살펴보았다. 완전요인 실험계획에 의하여 획득한 데이터는 반응표면 회귀 분석법으로 통계처리 후 정준분석을 실시하여 목적변수의 최고값을 결정하였다. 분급 비율은 미분 분급물과 조분 분급물 모두 분쇄기 회전속도, 분리기 휠 회전속도, 공기분급 휠 회전속도에 유의적으로 영향을 받았다. 분급물 평균 입자 크기는 미분의 경우 분급기 휠 회전속도의 영향을 받았지만, 조분의 경우 분쇄기 회전속도와 분리기 휠 회전속도의 영향을 받았다. 총 식이섬유는 미분의 경우 분쇄기 회전속도와 공기분급 휠 회전속도의 영향을 받았고, 조분의 경우 분쇄기 회전속도), 분리기 휠 회전속도, 공기분급 휠 회전속도(의 영향을 받았다. 미세화된 식이섬유 소재의 대량 생산을 위하여 공정 최적화를 실시한 결과 미분 분급물은 mill grinding speed 5,800 rpm, separate reverse wheel speed 2,954.6 rpm 그리고 air classification reverse wheel speed 349.5 rpm에서 총 식이섬유 함량 39.52 g/100 g, 평균입자 63.05 μm, 분급비율 44.98%로 예측되었다. 조분 분급물은 mill grinding speed 5,500 rpm, separate reverse wheel speed 2,500 rpm 그리고 air classification reverse wheel speed 600 rpm에서 총 식이섬유 함량 57.48 g/100 g, 평균입자 402.62 μm, 분급비율 70.64%로 예측되어, 조분 분급물을 통한 식이섬유 강화 식품 소재로서의 가능성을 발견 할 수 있었다.

This experimental work was performed to reveal the effect of intake air temperature on the improvement of performance and exhaust emissions in a SI engine. To achieve this, fuel consumption rate, combustion pressure, rate of heat release, and reduction of exhaust emissions were measured and compared in 4-cylinder spark ignition engine. It was founded that lower intake air temperature can lead higher combustion pressure and heat release rate due to the higher intake air flow rate, volumetric efficiency, and fuel consumption rate. At the same time, higher intake air temperature leads to the longer ignition delay time, therefore, retarded ignition of engine was observed. Lower CO and HC values were also observed as the intake air temperature increases.

PURPOSES: This research is to evaluate the mechanical performance of different types of Hot Mix Asphalt (HMA) pavement cells prepared for MN/Road field testing section through an extensive experimental analysis of air voids and simple statistical evaluation tools (i.e. hypothesis test). METHODS: An extensive experimental work was performed to measure air voids in 82 asphalt mixture cores (238 samples in total) obtained from nine different types of road cell located in MN/Road testing field. In order to numerically and quantitatively address the differences in air voids among the different test Cells built in MN/Road, a simple statistical test method (i.e. t-test) with 5% significance was used. RESULTS: Similar trends in air voids content were found among the mixtures including conventional HMA, Reclaimed Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA) combined with taconite aggregate this provides support to the use of RAP and WMA technology in the constructions of asphalt pavement. However, in case of acid modified HMA mixtures, significant differences in air void content were observed between on the wheel path and between wheel path location, which implies negative performances in rutting and thermal cracking resistances. Conclusions : It can be concluded that use of RAP and WMA technology in the construction of conventional asphalt pavement and the use of PPA (Poly Phosphoric Acid) in combinations with SBS (Styrene Butadiene Styrene) in asphalt binder production provide satisfactory performance and, therefore, are highly recommended

Societal concerns associated with aviation industry’s carbon-intensive nature and impending peak oil has become more pronounced over the last decade. With a potential to address both of these issues, the use of biofuels in aviation stands as the most promising pathway towards achieving sustainable air transport system. Significant progress continues to be made in overcoming technological and economic challenges of using 2nd generation biofuels in air transport industry. However, a truly sustainable and effective market deployment of aviation biofuels requires an extensive collaboration between feedstock providers, biofuel producers, governments, airlines, and the public. Thus, we deploy a multi-level perspective (MLP) framework to analyze these interactions on a micro- (niches), meso- (regime), and macro- (landscape) level. In particular, the framework captures the significance of international nature of air transport industry and the inter-industry dependencies of biofuel supply-chain. The results of this study highlight the barriers, drivers, and strategies for advancing social acceptance and establishment of sustainable aviation biofuel market.

In this paper, the wave run-up height and depression depth around air-water interface-piercing circular cylinder have been numerically studied. The Reynolds Averaged Navier-Stokes equations (RANS) and continuity equations are solved with Reynolds Stress model (RSM) and volume of fluid (VOF) method as turbulence model and free surface modeling, respectively. A commercial Computational Fluid Dynamics (CFD) software “Star-CCM+” has been used for the current simulations. Various Froude numbers ranged from 0.2 to 1.6 are used to investigate the change of air-water interface structures around the cylinder and experimental data and theoretical values by Bernoulli are compared. The present results showed a good agreement with other studies. Kelvin waves behind the cylinder were generated and its wave lengths are longer as Froude numbers increase and they have good agreement with theoretical values. And its angles are smaller with the increase of Froude numbers.

Numerical analysis has been carried out to investigate particles behavior characteristics during the grinding process in the air. Grinding particles behavior is largely affected by many parameters such as operating conditions and process room geometry. Transient particle motion in the air is predicted, and the effects of particle diameter and device rotational speed on the behavior characteristics were compared. When particle size is not large enough, they shortly moves in a tangential direction of the device rotation, and then are mostly influenced by the air flow in the room. These results could be applicable to the optimal design of the grinding process room.

아연공기전지의 분리막으로 사용하기 위한 Polyetherimide (PEI) 재질의 막을 제조하였다. 막의 제조는 상전이법을 통하여 이루어졌으며, 캐스팅 용액은 PEI, n-methylpyrolidone (NMP) 및 polyvinylpyrolidone (PVP)으로 이루어졌다. 제조한 분리막을 이용하여 아연공기전지를 제작하였다. 캐스팅 용액 내의 PEI 함량과 캐스팅 용액에 대한 PVP 첨가량이 분리막의 모폴로지, 기계적 강도와 이온전도도에 미치는 영향은 각각 SEM, 인장강도실험 및 임피던스 실험을 통하여 측정, 평가하였다. 아연공기전지의 전기화학적 성능은 정전류 방전실험을 통하여 측정하였다. 캐스팅 용액 중의 PEI 함량이 증가함에 따라 분리막의 기계적 강도는 증가하였으며, 캐스팅 용액에의 PVP 첨가는 분리막의 기계적 강도에 큰 영향을 미치지 않았다.용액 내의 PEI 함량이 증가하면서 분리막의 이온전도도는 감소하였다. 용액에 PVP를 첨가하는 데에 있어서 첨가량 10 wt%까지는 첨가량의 증가에 따라 분리막의 이온전도도는 증가하였다. PVP 첨가량이 10 wt%에서 이온전도도는 0.1 S/cm의 최대값을 보인 후 추가의 첨가에 따라서는 이온전도도가 감소하였다. 분리막의 이온전도도는 공기아연전지의 용량에 큰 영향을 미쳤으며, 높은 이온전도도를 갖는 분리막으로 제조한 전지가 높은 용량을 보였다.

In order to evaluate the quality of indoor air due to the remodeling and newly-built in S City, 60 schools wereinvestigated in formaldehyde (HCHO) and total volatile organic compounds (TVOCs). One school exceeded thenational standard of formaldehyde 100µg/m³ at 1st measurement. Thirty-eight schools showed higher level ofTVOCs over 400µg/m³ at 1st measurement. Twelve schools showed higher level of TVOCs over 400µg/m³ at2nd measurement. This result derived from TVOCs which originated from the building materials and finishingmaterials. To prevent the pollution of indoor air quality at schools caused by formaldehyde and TVOCs, therecommendation of environmentally-friendly building materials, the diminishment of emission by bakeout process,the efficient combination of natural ventilation and mechanical ventilation, and antibacterial effect of chemicalcontrol measures as photo-catalysts should be given positive investigation.