In this study, we propose a flow velocity evaluation scheme based on pressure measurement in pressurized pipeline systems. Conservation of mass and momentum equations can be decomposed into mean and perturbation of pressure head and flowrate, which provide the pressure head and flowrate relationship between upstream and donwstream point in pressurized pipeline system. The inverse impedance formulations were derived to address measured pressure at downstream to evaluation of flow velocity or pressure at any point of system. The convolution of response function to pressure head in downstream valve provides the flow velocity response in any point of the simple pipeline system. Simulation comparison between traditional method of characteristics and the proposed method provide good agreements between two distinct approaches.

In this study, a method of leakage detection was proposed to locate leak position for a reservoir pipeline valve system using wavelet coherence analysis for an injected pressure wave. An unsteady flow analyzer handled nonlinear valve maneuver and corresponding experimental result were compared. Time series of pressure head were analyzed through wavelet coherence analysis both for no leak and leak conditions. The leak information can be obtained through either time domain reflectometry or the difference in wavelet coherence level, which provide predictions in terms of leak location. The reconstructed pressure signal facilitates the identification of leak presence comparing with existing wavelet coherence analysis.

이 연구에서 지리산의 낮은 고도에서부터 높은 고도까 지 나비의 종다양성, 고도에 따른 생태적 특성, 우점종의 고도 분포에 대해 알아보았다. 나비는 총 5과 58종 769개체의 나비를 확인하였다. 낮은 고도와 높은 고도에서 종다양성은 높게 나타나고 있었다. 군집분석을 통해 3개 (낮은 고도, 중간 고도, 높은 고도)로 구분하였으며, 낮은 고도에 비해 높은 고도에서는 서식지 범위가 좁은 종의 비율이 높았으며, 단식성 나비의 비율이 높게 나타나고, 다화성 나비의 비율이 높게 나타났다. 배추흰나비 (Pieris rapae)는 600 m 이하의 고도에서 서식하고, 큰흰줄표범나비 (Argynnis ruslana), 먹그늘나비 (Lethe diana)는 900 m 이상의 고도에 서식하며, 특히 큰흰줄표범나비 (Argynnis ruslana)는 1,000 m 이상에서 서식하고 있었다. 본 연구를 바탕으로 지속적인 모니터링 실시를 통해 지리산에서 기후변화에 따른 나비의 고도 분포 변화 및 다양성 변화 양상을 확인할 수 있을 것으로 생각된다.

This study examines the effects of surrounding outdoor environmental characteristics in multi-use public facilities that are used by the susceptible population, on the concentration and distribution of indoor airborne bacteria. For this study, areas were divided into ‘factory area,’ ‘city area,’ and ‘forest area.’ The research was conducted from October 2017 to April 2018, and the selected target facilities were daycare centers, hospitals, postpartum care centers, and nursing homes for the elderly. In order to measure airborne bacteria, indoor air samples were collected using a six-stage viable particulate cascade impactor, and airborne bacteria samples were collected using MCE (Mixed cellulose esters) filters. Moreover, the outdoor airborne bacteria concentration was also measured to determine the concentration ratio (I/O ratio) of the total indoor airborne bacteria and total outdoor airborne bacteria concentrations. The results showed that the total outdoor airborne bacteria concentration was highest in the city area, with 74.2 ± 60.0 CFU/m3, and the lowest in the factory area, with 45.9 ± 35.8 CFU/m3. Furthermore, the distribution of the total outdoor airborne bacteria concentrations significantly differed across each surrounding environment (p < 0.05). On the other hand, no statistically significant difference in total indoor airborne bacteria concentrations, according to surrounding environments, was observed (p > 0.05). These findings suggest that the concentration of outdoor airborne bacteria differs across surrounding environments, unlike that of the indoor airborne bacteria.

This paper suggests a nonlinear pressure consideration scheme through an unsteady pipe network analyzer for leakage detection with a portable pressure wave generator. In order to evaluate the performance of a proposal scheme, linear input pattern has been simulated and experiments had been carried out under both no leakage and one leakage conditions in a reservoir-pipeline-valve system. This method using portable pressure wave generator showed that a leakage can be detected from a reflection where a leakage is originated through time domain analysis. Meaningful similarity in pressure response between nonlinear input pattern and experimental results were found both no leakage and a leakage conditions.

The purpose of this study was to analyze the effects of sewerage facilities through I/I analysis by rainfall by selecting areas where storm overflow diverging chamber is remained due to the non-maintenance drainage equipment when the sewerage system was reconstructed as a separate sewer system. Research has shown that wet weather flow(WWF) increased from 106.2% to 154.8% compared to dry weather flow(DWF) in intercepting sewers, and that the WWF increased from 122.4% to 257.6% in comparison to DWF in storm overflow diverging chamber. As a result, owing to storm overflow diverging chamber of partially separate sewer system with untreated tributary of sewage treatment plant, rainfall-derived infiltration/inflow(RDII) has been analyzed 2.7 times higher than the areas without storm overflow diverging chamber. Meanwhile, infiltration quantity of this study area was relatively higher than that of other study areas. Therefore, it is necessary to reduce infiltration quantity through sewer pipe maintenance nearby river. Drainage equipment maintenance should be performed not to operate storm overflow diverging chamber in order to handle the appropriate sewage treatment plant capacity for rainfall because it is also expected that RDII due to rain will occur after maintenance. In conclusion, it is necessary to recognize aRDII(allowance of rainfall-derived infiltration/inflow) and to be reflected it on sewage treatment plant capacity because aRDII can occur even after maintenance to the complete separate sewer system.

경북 안동 사문암 지역의 소나무군락에서 2017년 01월부터 2017년 12월까지 1년간 매목조사, 미기상 및 토양호흡 측정을 통해 탄소수지를 측정하였다. 사문암 지역에서 토양호흡량은 연중 42.48 ~ 262.61 g CO2･m-2･month-1의 범위 로, 평균 151.71 ± 75.09 g CO2･m-2･month-1로 측정되었다. 대조구인 비사문암 지역의 소나무림에서는 연중 20.94 ~ 449.24 g CO2･m-2･month-1의 범위로 조사되었으며, 평균 165.09 ± 118.96 g CO2･m-2･month-1로 측정되었다. 사문암 지역과 비사문암 지역의 총 탄소저장량은 각각 91.90, 222.85 ton･ha-1로 나타났으며, 연간 탄소흡수량은 각각 7.99, 17.41 ton･ha-1･yr-1로 나타났다. 사문암 지역은 연간 5.3 ton C･ha-1, 비사문암 지역은 연간 14.49 ton C･ha-1를 흡수하는 것으로 나타났다.

Mold grows more easily when humidity is higher in indoor spaces, and as such is found more often on wetted areas in housing such as walls, toilets, kitchens, and poorly managed spaces. However, there have been few studies that have specifically assessed the level of mold in the indoor spaces of water-damaged housing in the Republic of Korea. We investigated the levels of airborne mold according to the characteristics of water damage types and explored the correlation between the distribution of mold genera and the characteristics of households. Samplings were performed from January 2016 to June 2018 in 97 housing units with water leakage or condensation, or a history of flooding, and in 61 general housing units in the metropolitan and Busan area, respectively. Airborne mold was collected on MEA (Malt extract agar) at flow rate of 100 L/min for 1 min. After collection, the samples were incubated at 25oC for 120 hours. The cultured samples were counted and corrected using a positive hole conversion table. The samples were then analyzed by single colony culture, DNA extraction, gene amplification, and sequencing. By type of housing, concentrations of airborne mold were highest in flooded housing, followed by water-leaked or highly condensed housings, and then general housing. In more than 50% of water-damaged housing, the level of airborne mold exceeded the guideline of Korea's Ministry of Environment (500 CFU/m3). Of particular concern was the fact that the I/O ratio of water-damaged housing was greater than 1, which could indicate that mold damage may occur indoors. The distribution patterns of the fungal species were as follows: Penicillium spp., Cladosporium spp. (14%), Aspergillus spp. (13%) and Alternaria spp. (3%), but significant differences of their levels in indoor spaces were not found. Our findings indicate that high levels of mold damage were found in housing with water damage, and Aspergillus flavus and Penicillium brevicompactum were more dominant in housing with high water activity. Comprehensive management of flooded or water-damaged housing is necessary to reduce fungal exposure.

In this study, the condition of the hazardous materials in the bus was monitored according to the ventilation mode of the air conditioning system during bus service. The bus was surveyed using the indoor air quality measurement method of public transportation vehicles within one year of delivery. We evaluate the CO2 and PM10, which are the controlled parameters in buses by the Ministry of Environment, and VOCs and HCHO, the non-controlled parameters. The PM10 concentration increased due to outdoor air intake; however the CO2 concentration was found to decrease. In addition, the concentration of VOCs and HCHO was found to decrease due to the forced ventilation system and the outdoor air intake. These results show that the concentration of the other materials except PM10 can be changed due to the outside air concentration and forced ventilation system. Therefore, through indoor air quality characteristics of the bus according to air condition system are intended to be used as the basis of an operation manual.

H13 tool steels are widely used as metallic mold materials due to their high hardness and thermal stability. Recently, many studies are undertaken to satisfy the demands for manufacturing the complex shape of the mold using a 3D printing technique. It is reported that the mechanical properties of 3D printed materials are lower than those of commercial forged alloys owing to micropores. In this study, we investigate the effect of microstructures and defects on mechanical properties in the 3D printed H13 tool steels. H13 tool steel is fabricated using a selective laser melting(SLM) process with a scan speed of 200 mm/ s and a layer thickness of 25 μm. Microstructures are observed and porosities are measured by optical and scanning electron microscopy in the X-, Y-, and Z-directions with various the build heights. Tiny keyhole type pores are observed with a porosity of 0.4%, which shows the lowest porosity in the center region. The measured Vickers hardness is around 550 HV and the yield and tensile strength are 1400 and 1700 MPa, respectively. The tensile properties are predicted using two empirical equations through the measured values of the Vickers hardness. The prediction of tensile strength has high accuracy with the experimental data of the 3D printed H13 tool steel. The effects of porosities and unmelted powders on mechanical properties are also elucidated by the metallic fractography analysis to understand tensile and fracture behavior.

The purpose of this study is to implement through the utilization of geographical information that was currently constructed in the development of the radon map creation methodology. In addition, we suggested a model for forecasting radon gas in soil based on the mechanism of radon exhalation from soil. To provide basic data for radon mapping in Korea, we compared the results obtained using the proposed model with the results of a field survey. Based on the comparison, we discussed the feasibility of the proposed model. The soil radon exhalation rate prediction model was built on the first order prediction model in the steady-state based on the law of conversion of mass. To verify the model by comparing the predicted value with a field survey, a grid of 7.5 × 6.3 cm was created at a 1:500,000 map of Korea, and the intersection point of the grid was selected as measurement site. The results showed a low error rate when compared with the previous studies, and it is expected that the model proposed in this study and the currently constructed geogenic information database can be used in combination to map the soil radon gas in Korea.

For performance analysis of flood prevention projects, this study performed simulation (SWMM) for the five sites where the projects have been completed. The models were constructed using watershed and sewer information of the project sites and were verified using flood records in the past to improve accuracy. In this simulation, the design rainfall data (probability 30~50 years) and the rainfall data in the summer of 2017 were applied. When the design rainfall data was applied to the models, simulation results presented that all the sites were flooded before the projects, but after the projects all the sites were not flooded due to improve discharge capacity. And when the rainfall data in the summer of 2017 was applied to the models, simulation results presented that all the sites were flooded before the projects, but after the projects any sites did not occur flooding in this summer. So if the projects had not been completed, all the sites might be flooded in the summer of 2017. These effects were analyzed as the improvement of discharge capacity due to rehabilitation of sewer, construction of underground tunnel and pumping station, etc. As the results, ratio of sewer that water depth exceed diameter reduced from 52.3~75.8% to 17.1~39.8%.

최근 지구온난화를 포함한 환경 변화는 생태계 전체에 큰 영향을 미칠 뿐만 아니라 사회, 문화, 경제적으로도막대한 영향을 미치고 있다. 기온상승과 같은 기후변화에 따라 우리나라 자연 환경이 변화하고 이와 밀접한 관련이있는 동식물상 변화 역시 예상된다. 변온동물로 종 다양성이 풍부한 나방은 분류학적 정보가 비교적 자세하고서식지 특이성이 높으며 자외선등 트랩을 이용하여 쉽고 정량적인 채집이 가능하기 때문에 환경변화를 모니터링하기에 적절하다. 우리는 2001년부터 최근까지 한반도 남부 지방을 중심으로 지리산, 무안 승달산, 제주 한라산 등지에서5월부터 10월까지 매달 1회씩 모니터링을 진행하고 있다. 이러한 모니터링을 통하여 남부지역의 나비목 종 다양성을밝혀낼 수 있었을 뿐만 아니라 환경변화에 따른 특정 개체군의 감소 또는 증가를 확인할 수 있었다. 나방 모니터링을통하여 얻었던 중요한 연구결과 뿐만 아니라 앞으로의 방향에 대해서도 논의할 계획이다.

During the decay process of food waste, odor and leachate are generally produced because food is easily decomposed due to its high organic and moisture contents. In this study, various food waste samples, including samples artificially prepared and collected from actual waste containers, were tested to determine odor and leachate production as the samples were decomposed at a constant temperature of 35°C. In the air phase, total volatile organic compounds (TVOCs), acetaldehyde (AA), methyl mercaptan (MM), hydrogen sulfide (H2S), and dimethyl sulfide (DMS) were measured as a function of the decay period for four days. The results of the experiment showed that TVOC and AA were produced at higher concentrations in the actual food waste than in all artificial wastes. The AA concentration accounted for about 90% of the TVOC in all of the waste samples except for the food waste containing meat and fish only. The concentrations of volatile sulfur compounds (VSCs) were generally lower than 100 μg/kg, and the concentration of DMS was the highest among the VSCs. In the waste sample containing meat and fish only; however, the concentration of VSCs increased up to 1,700 μg/kg, and mostly consisted of MM and DMS. Complex odor concentrations were found to be the highest after a decay period of 12-48 hours. In addition, the complex odor was mostly related to VSCs with low odor thresholds rather than the TVOC. The pH values mostly decreased from 5 to 3.5 as the waste samples were in the decomposition periods, while the pH value increased to 6 in the food waste containing meat and fish only. Consequently, odor intensity and leachate production were the highest in the 12-48 hour range as the decomposition started, and thus an appropriate control strategy needs to be implemented based on the waste composition and the decay period.

Sweet potato-malt worts were prepared by using sweet potato paste of Shinyulmi and Shinjami as the main adjunct, enzymes, malt, hop, and water. We brewed low-malt beers of the lager- or ale-type by using these worts and inoculating bottom and top fermenting yeast, respectively. Moreover, the componential and functional characteristics of the resulting beers were evaluated. During saccharification of sweet potato, the addition of an enzyme agent containing α-amylase caused an improvement in filterability and an increase of total sugar. The sugar content of sweet potato-malt wort which was prepared by the addition of 0.1% enzyme agent containing α-amylase and a three-step infusion procedure was 13.5 °Brix adequate for beer brewing. The polyphenol and anthocyanin contents of Shinjami beer were increased with increasing content of the paste, and also increased DPPH and ABTS radical scavenging activities. But in Shinyulmi beer it were decreased. A strong correlation was obserbed between antioxidave activities and polyphenol and anthocyanin contents of sweet potato beers. In all lager- and ale-type low-malt beers using 41.6% of Shinjami pastes, sensory attributes very similar to those of 100% malt beer were obtained and they were very good as they had unique red color.

This research focused on deciding optimal manufacturing WIP (Work-In-Process) limit for a small production system. Reducing WIP leads to stable capacity, better manufacturing flow and decrease inventory. WIP is the one of the important issue, since it can affect manufacturing area, like productivity and line efficiency and bottlenecks in manufacturing process. Several approaches implemented in this research. First, two strategies applied to decide WIP limit. One is roulette wheel selection and the other one is elite strategy. Second, for each strategy, JIT (Just In Time), CONWIP (Constant WIP), Gated Max WIP System and CWIPL (Critical WIP Loops) system applied to find a best material flow mechanism. Therefore, pull control system is preferred to control production line efficiently. In the production line, the WIP limit has been decided based on mathematical models or expert’s decision. However, due to the complexity of the process or increase of the variables, it is difficult to obtain optimal WIP limit. To obtain an optimal WIP limit, GA applied in each material control system. When evaluating the performance of the result, fitness function is used by reflecting WIP parameter. Elite strategy showed better performance than roulette wheel selection when evaluating fitness value. Elite strategy reach to the optimal WIP limit faster than roulette wheel selection and generation time is short. For this reason, this study proposes a fast and reliable method for determining the WIP level by applying genetic algorithm to pull system based production process. This research showed that this method could be applied to a more complex production system.

Spodoptera litura (Fabricius, 1775) is considered as a serious agricultural pest, which damaged to the many crops including sweet potato (Ipomoea batatas). We investigated weekly occurrence of the Spodoptera litura (Fabricius) using pheromone trap at six study fields of three regions, Jeonnam, Korea. A total of 41,895 individuals were collected from 18th July to 23th September in 2013; Yeongamgun was collected the highest individuals (17,519), and following the Muan-gun (12,709) and Haenamgun (11,667). The seasonal occurrence of S. Litura was increased from July to September, and peak occurrence timing was in late-September. There were a positive correlation between field area and number of individuals (P=0.02, r=0.89), and a negative correlation between field area and density (p=0.02, r=-0.89). As a PCA (principal component analysis) result, adults occurrence pattern were closely related to the temperature and relative humidity during larva stage.

For economic evaluation of integrated operation to sewage facilities, benefit-cost analysis was performed to watershed sewage works project in 7 watershed areas, 156 facilities. In this study, the cost before and after integrated operation was compared and benefits are calculated from the reduction of operators, increasement treated pollution loads, reduction cost through operation convenience, reduction water consumption through effluent reuse, and improvement of life benefit. The result showed that cost was 8,500million won and benefit was 16,747million won, so benefit was 49% higher than cost. B/C analysis result showed that B/C ratio was 1.97 and it is similar to other researches. The benefits of integrated operation included convenience of data management, increase of emergency response, decrease of complains with sewage which was not reflected numerically, so the benefits of integrated operation were expected much greater than this result.

Transparent organic-inorganic hybrid hard coating films were prepared by the addition of SiO2 or ZrO2, as an inorganic filler to improve the hardness property, filler was highly dispersed in the acrylic resin. To improve the compatibility in the acrylic resin, SiO2 or ZrO2 is surface-modified using various silanes with variation of the modification time and silane content. Depending on the content and kind of the modified inorganic oxide, transparent modified inorganic sols were formulated in acryl resin. Then, the sols were bar coated and cured on PET films to investigate the optical and mechanical properties. The optimized film, which has a modified ZrO2 content of 4 wt% markedly improved in terms of the hardness, haze, and transparency as compared to neat acrylate resin and acrylate resin containing modified SiO2 content of 8 wt%. Meanwhile, the low transparency and high haze of these films slowly appeared at SiO2 content above 10 wt% and ZrO2 content of 5 wt%, but the hardness values were maintained at 2H and 3H, respectively, in comparison with the HB of neat acrylate resin.