본 연구는 표고균사체 발효 적하수오 열수 최적 추출조건 탐색을 목적으로 수행하였으며, 표고균사로 배양된 하수오의 독립변수로는 독립변수(Xi)로서 추출온도(X1), 추출시간(X2) 및 시료에 대한 용매비(X3)에 대한 실험범위를 설정하여 각각을 5단계로 부호화하였고 중심합성계획에 따라 16구로 설정하여 추출하였다. 또한 이들 독립변수에 영향을 받을 종속변수(Yn)로는 고형분 함량(Y1) 및 당도(Y2), TPC (total polyphenol contents, Y3), TFC (total flavonoid contents, Y4), ABTS cation radical scavenging activity (Y5), DPPH radical scavenging activity (Y6)으로 하였다. 고용분 함량 최대값과 최소값은 각각 31.99%와 16.84%로 나타났다. 이를 회귀분석한 결과 고형분 함량에 대한 모델식의 R2은 0.867로 나타났다. 당도는 7번(8 hrs, 85℃, 67 mg/mL)과 15번(6 hrs, 70℃, 100 mg/mL)시험구에서 3.0 brix로 다른 시험구에 비하여 높은 함량을 보였다. 항산화물질인 총 폴리페놀과 플라보노이드 함량은 8번 시험구(8 hrs, 85℃, 40 mg/mL)에서 총 폴리페놀 함량이 30.40 mg GAE/g, 총 플라보노이드 함량이 146.50 mg QE/g으로 가장 높게 나타났으며, 16가지 시험구의 항산화 활성도 총 폴리페놀과 총 플라보노이드 함량의 결과와 같이 8번 시험구(8 hrs, 85℃, 40 mg/mL)에서 가장 높은 활성을 보였다. 이상의 결과를 참조하여 표고균사체 발효 적하수오에 대한 열수 추출조건을 최적화할 목적으로 추출온도를 95℃로 고정하고 용매비와 추출시간에 대한 종속변수들의 contour map을 superimposing하여 추출물의 특성 중 생리활성물질 함량과 생리활성을 만족시켜주는 최적조건은 91.22℃에서 39.71 mg/mL 용매비와 7.72 추출시간으로 각각 분석되었다. 본 연구는 적하수오에 표고균사체를 배양한 후 생리활성이 우수한 원료를 추출 생산하고자 최적 추출조건을 확립하기 위하여 반응표면분석법을 활용하였다. 향후 생리활성부분에 대한 추가적인 연구가 이루어진다면 더욱 완성도가 높은 표고균사체 발효 적하수오 식품개발에 가능할 것으로 사료된다.

This study investigated the effects of blanching time (1-5 min), types of blanching solution (1% NaCl vs 1-3% sucrose), addition of packaging with blanching solution, and thawing methods (thawing in packaged versus depackaged units) on the qualities of frozen Aster scaber. As quality parameters, drip loss, moisture content, shear force, color, and sensory test were conducted. Aster scaber was blanched in 1% sucrose for 4 min and packaged with the same solution prior to freezing whereas frozen Aster scaber exhibited palatable quality when it was removed from the package and thawed in running water. Consequently, this study demonstrated that the optimized processing condition provided qualities like non-frozen control.

Recently, interest in the development of alternative water resources has been increasing rapidly due to environmental pollution and depletion of water resources. In particular, seawater desalination has been attracting the most attention as alternative water resources. As seawater desalination consumes a large amount of energy due to high operating pressure, many researches have been conducted to improve energy efficiency such as energy recovery device (ERD). Consequently, this study aims to compare the energy efficiency of RO process according to ERD of isobaric type which is applied in scientific control pilot plant process of each 100 m3/day scale based on actual RO product water. As a result, it was confirmed that efficiency, mixing rate, and permeate conductivity were different depending on the size of the apparatus even though the same principle of the ERD was applied. It is believed that this is caused by the difference in cross-sectional area of the contacted portion for pressure transfer inside the ERD. Therefore, further study is needed to confirm the optimum conditions what is applicable to the actual process considering the correlation with other factors as well as the factors obtained from the previous experiments.

Desalination plants have been recently constructed in many parts of the world due to water scarcity caused by population growth, industrialization and climate change. Most seawater desalination plants are designed with a submarine pipeline for intake and discharge. Submarine pipelines are installed directly on the bottom of the water body if the bottom is sandy and flat. Intake is located on a low-energy shoreline with minimal exposure to beach erosion, heavy storms, typhoons, tsunamis, or strong underwater currents. Typically, HDPE (High Density Polyethylene) pipes are used in such a configuration. Submarine pipelines cause many problems when they are not properly designed; HDPE pipelines can be floated or exposed to strong currents and wind or tidal action. This study examines the optimal design method for the trench depth of pipeline, analysis of on-bottom stability and dilution of the concentrate based on the desalination plant conducted at the Pacific coast of Peru, Chilca. As a result of this study, the submarine pipeline should be trenched at least below 1.8 m. The same direction of pipeline with the main wind is a key factor to achieve economic stability. The concentrate should be discharged as much as high position to yield high dilution rate.

PURPOSES : The objective of this research is establishing system components and optimizing operational procedures in order to systematically manage road cave-ins in urban areas.METHODS: Based on the literature review and alternative comparison, optimization methods is suggested.RESULTS : Throughout the study, location referencing system, database structure, and operation strategy(procedure) were clarified, and the optimization methods for each item were suggested.CONCLUSIONS: Road cave-in management should be focused on user safety rather than focusing on economic aspects. The occurrence of road cave-in should be addressed thoroughly by road management system(location referencing system, database structure, and operation strategy(procedure), and the optimization methods), since they are closely related to road users' safety.

사회적으로 안전에 대한 관심이 많아지고 있는 상황에서 계속되는 북한의 미사일 실험은 이를 대비한 민방위 대피시설의 운영 실태를 점검하는 계기가 되었다. 본 연구에서는 공간 최적화 접근을 통하여 개별 대피시설 수준에서 서비스 커버리지와 수용 능력을 평가하였다. 특히 수요를 상주인구로 재현하였을 때와 현주인구로 재현하였을 때 모델링 결과가 어떻게 달라지는지 분석하였다. 사례지역으로 대구광역시 서구의 민방위 대피시설의 커버리지를 평가하였다. 그 결과, 지정된 민방위 대피시설에 의해서 커버되지 않은 현주인구가 상주인구에 비하여 절대적으로 뿐만 아니라 상대적으로 많았다. 또한 기존 대피시설에 의해서 커버되지 않는 상주인구와 현주인구의 위치가 달랐다. 마지막으로 개별 대피시설에 할당된 인구를 수용가능 인구와 비교해 본 결과 대체로 시설의 규모가 클수록 실제 수용률이 낮게 나타났다. 이러한 공간 최적화 접근을 통하여 도출한 정보는 재난관리를 보다 구체적이고 체계적으로 만드는데 기여할 것이다.

Acetic acid bacteria strains were isolated from a variety of fermented foods and fallen fruits. Among them, the strain MAK88, whose acetic acid fermentation ability, acid-tolerance, and alcohol-tolerance were high, was selected and identified as Acetobacter orientalis. A seed culture of A. orientalis MAK88 was inoculated into onion juice, and the optimum conditions of acetic acid fermentation was investigated. The optimum initial concentration of ethanol in onion juice was 5% (v/v) and in that condition, acidity was 4.31% at 144 h of fermentation. The optimum initial concentration of acetic acid was 1% and the final acidity was 5.32%. The optimum fermentation temperature was determined to be 28oC. The most appropriate preparation method of onion juice was to heat the onion at 121oC for 15 min and produce juice with pressure followed by filtering, and then sterilization at 121oC for 15 min. Prepared onion juice was used for fermentation without dilution.

Glucansucrase is an enzyme classified as a glycoside hydrolase (GH) 70 family, which catalyzes the synthesis of glucooligosaccharides with a low molecular weight using sucrose as a donor of D-glucopyranose and maltose as a carbohydrate acceptor. In this study, glucansucrase-producing lactic acid bacteria strain was isolated from the fermented foods collected in traditional markets, and the optimum conditions for the oligosaccharide production were investigated. The strain CCK940 isolated from Chinese cabbage kimchi was selected as an oligosaccharide-producing strain due to its high glucansucrase activity, with 918.2 mU/mL, and identified as Leuconostoc lactis. The optimum conditions for the production of oligosaccharides using Leu. lactis CCK940 were to adjust the initial pH to 6.0, add 5% (w/v) sucrose and 10% (w/v) maltose as a donor and acceptor molecules, respectively, and feed 5% (w/v) sucrose at 4 and 8 h of cultivation. When Leu. lactis CCK940 was cultured for 12 h at optimum conditions, at least four oligosaccharides with a polymerization degree of 2-4 were produced.

Ceramic membranes can be applied under extreme operating conditions such as low pH, high pressure and high temperature. In particular SiC has excellent mechanical properties and also has excellent properties related to membrane performance. However, high processing temperature increases cost of SiC products and thus limit’s its use. In this study oxidation bonding technique was used to fabricate cost-effective SiC microfiltration membrane at low temperature. The oxidation behavior at different thermal treatments was related with pore morphology and ultimately the membrane permeability. We have found that the membrane made by coating of oxidation bonded SiC layer over clay-bonded SiC support, sintered at 1000-1100°C could make a defect-free microfiltration membrane with pure water permeability above 700 LMH per bar. The membrane has narrow pore size distribution with average pore size about 0.1 μm.

As the size of the wind turbine tower becomes larger and larger, research on assembled wind turbine tower that is advantageous for transportation and installation is continuing. Large wind turbine tower require door openings for maintenance. The opening of the tower has an irregular cross section, and an excessive stress is generated due to the door opening. The result is structural damage to the tower and many accidents. In this research, stress analysis was performed on a model with internal stiffener to prevent excessive stress. The stress was investigated around the openings where the tower was resonant and excessive stressed, and the shape of the openings was optimized. Through optimization, we confirmed that the maximum stress was reduced by about 6% with respect to the initial value.

In recent years there have been large increases in the hydraulic loading rates used to design dissolved air flotation (DAF) facilities for drinking water applications. High rate DAF processes are now available at loading rates of 20 to 40 m3/m2·h. This research evaluated dissolved air flotation as a separation method for algae and organic compounds from water treatment plants. During the service period of 2016. 5. to 2017. 6., DAF pilot plants (500 m3/day) process has shown a constantly sound performance for the treatment of raw water, yielding a significantly low level of turbidity (DAF treated water, 0.21～1.56 NTU). As a result of analyzing the algae cell counts in the influent source, it was expressed at 100-120 cells/mL. In DAF treated water, the removal efficient of alge cell counts was found to be upto 90%. The stable turbidity and algae removal were confirmed by operating the high rate DAF process under the condition of the surface loading rate of 30 m3/m2·hr.

최근 전 세계적으로 SNS, 매스컴 등을 통해 싱크홀(Sinkhole)이 사회적 이슈가 됐다. 특히, 포장도로 하부 동공으로 인해 발생하는 도로함몰은 도로이용자에게 직접적인 안전상의 위험이 되기 때문에 시민들의 불안이 확산되고 있다. 서울시(2014)는 도로함몰에 대한 시민들의 불안을 조기에 해소하고 보다 안전하게 통행할 수 있는 도로환경을 조성하고자 ‘도로함몰 특별관리 대책’을 수립하여 발표했다. 환경부(2015)는 노후관로 약 40,000km 구간을 대상으로 정밀조사를 실시했으며 ‘하수관로 정밀조사 매뉴얼’을 발간했다. 국토부는 2018년부터 예방형 재난피해 지하시설물 관리를 위한 ‘지하시설물의 안전관리에 대한 특별법’을 공포했다. 이는 도로함몰의 사후 대책, 하수관 및 지하시설물의 관리 법률 등의 개선이다. 그러나 각 기관의 이러한 노력에도 불구하고 도로함몰을 체계적으로 관리하고 운영하는 시스템은 미흡한 상태이다. 도로함몰은 도심에 대규모로 발생하는 경우 도시의 이미지를 실추하고 도로이용자에게 안전상의 직접적 위협과 물적 피해를 야기하기 때문에 도로함몰에 집중된 관리전략이 필요하다. 전략에는 도로함몰의 조사, 분석, 예측, 평가, 보수, 모니터링, feedback의 체계적인 운영 절차와 구성요소의 최적화가 필요하다. 따라서 본 연구의 목적은 도로함몰관리시스템을 구성하는 위치정보, DB, 운영전략, 운영절차의 정의와 최적화 방안을 정리하고 분석하는 것이다. 그림 1.은 본 연구에서 제시하는 도로함몰 관리 시스템의 Tracking Tool과 Analysis Tool 사이의 System Framework의 구성이다

지구 온난화, 석유고갈, 환경오염에 대한 해결 방안으로 수송부분에서 국제적으로 바이오연 료에 관한 연구가 활발하게 이루어지고 있다. 그 중 바이오디젤은 석유계 디젤과 비교해 이산화탄소 및 대기오염 물질 배출이 적고 세탄가가 높은 장점을 가지고 있다. 현재 국내 바이오디젤 수요는 지속적으로 증가하고 있으나 원료부족으로 인해 수입의존도가 커지고 있는 상황이다. 이러한 문제를 해결하기 위해 본 연구는 현재 사용되지 않는 음폐유(약 33 % 유리지방 산 함유)를 Amberlyst-15 촉매가 이용한 에스테르화 반응을 통해 바이오디젤 원료로서 활용가능성을 확인 하였다. 다양한 반응 조건의 영향을 조사하기 위한 실험을 수행한 결과 반응온도 383 K에서 97.62 %의 전환 율을 얻었으며, 반응속도는 353 K에서 373 K로 증가 할 때 최대 1.99 배까지 상승하였다. 또한 동역학 적 결과를 이용하여 29.75 kJ/mol의 활성화 에너지를 확인하여 선행연구에서 연구된 타 고체촉매에 비 해 에스테르화반응에 Amberlyst-15 더 적합함을 확인하였다. 그리고 메탄올 몰 비가 증가함에 따라 최 대 91.43 %의 반응 전환율을 확인하였고, 촉매량 영향의 경우 0 wt%에서 20 wt%까지 증가시킨 결과 반응 전환율이 43.78 %에서 94.62 %까지, 초기 반응 속도는 1.1∼1.4 배로 상승하는 것을 확인하였 다. 교반속도의 경우 100∼900 rpm의 조건에 따라 실험을 수행하였으나 반응 전환율에는 큰 영향을 주 지 않음을 확인하였고 반응 시간에 따른 영향의 경우 240 분 까지 산가 감소를 보이다가 300 분이 지 나면서부터 산가가 상승하는 결과를 가져왔다. 그리고 위 실험들을 통해 도출된 최적 조건을 적용하여 음폐유 에스테르화 반응에 적용하였고 그 결과 반응시간 60 분에서 음폐유와 모사 폐유지간의 13 %의 반응 전환율 차이를 보였으나 최종 240 분 반응 전환율은 모사 폐유지 98.12 %, 음폐유는 97.62 %로 거의 유사한 결과를 얻었다.

2014년 12월 사용 승인된 경주 중저준위 방사성폐기물 동굴처분시설은 중저준위 방사성폐기물의 처분을 위해 운영중이나 중준위 방사성폐기물을 처분할 수 없다. 왜나하면 기존 중준위 방사성폐기물이 원자력안전위원회 고시 2014-003호에 따라 방사성폐기물 준위가 세분화되었으며, 기존의 중저준위 방사성폐기물 핵종별 처분농도제한치 값이 변경되었으나 이를 고려 하지 못하였기 때문이다. 중준위 방사성폐기물의 안전한 처분을 위해 IAEA에서 제시한 방법론과는 달리 방사능량 산출 시 적용된 가용데이터를 기반으로 기존의 설정된 극저준위 및 저준위 방사성폐기물의 처분농도제한치를 고려하여 1단계 동굴 처분시설의 중준위 방사성폐기물에 대한 처분농도제한치를 설정하였다. 단, 14C의 경우 처분농도제한치 외에 추가적인 방사 능량 제한이 필요함을 확인하고 우물이용시나리오를 통해 1단계 동굴처분시설의 총방사능량을 제한하였다. 설정된 중준위 방사성폐기물 처분농도제한치와 14C의 총방사능량이 적용된 방사능량에 대해 운영 중 및 폐쇄 후 시나리오의 평가결과가 모 두 성능목표치를 만족함을 확인하여, 도출된 중준위 방사성폐기물 처분농도제한치가 1단계 동굴처분시설의 중준위 방사성 폐기물 처분농도제한치로 사용할 수 있음을 확인하였다. 처분 안전성 증진을 위해 방사성폐기물 발생기관의 데이터를 추가 확보하며, 14C의 누적방사능량을 관리해 나갈 계획이다.

With the increased interest in the quality of life of modern people, the implementation of the five-day working week, the increase in traffic convenience, and the economic and social development, domestic and international travel is becoming commonplace. Furthermore, in the past, there were many cases of purchasing packaged goods of specialized travel agencies. However, as the development of the Internet improved the accessibility of information about the travel area, the tourist is changing the trend to plan the trip such as the choice of the destination. Web services have been introduced to recommend travel destinations and travel routes according to these needs of the customers. Therefore, after reviewing some of the most popular web services today, such as Stubby planner (http://www.stubbyplanner.com) and Earthtory (http://www.earthtory.com), they were supposed to be based on traditional Traveling Salesman Problems (TSPs), and the travel routes recommended by them included some practical limitations. That is, they were not considered important issues in the actual journey, such as the use of various transportation, travel expenses, the number of days, and lodging. Moreover, although to recommend travel destinations, there have been various studies such as using IoT (Internet of Things) technology and the analysis of cyberspatial Big Data on the web and SNS (Social Networking Service), there is little research to support travel routes considering the practical constraints. Therefore, this study proposes a new mathematical model for applying to travel route recommendation service, and it is verified by numerical experiments on travel to Jeju Island and trip to Europe including Germany, France and Czech Republic. It also expects to be able to provide more useful information to tourists in their travel plans through linkage with the services for recommending tourist attractions built in the Internet environment.

본 논문에서는 곤충 모방 날갯짓 초소형 비행체에 적용될 끈을 이용한 날갯짓 구동 장치의 구동 원리와 그 최적화 과정이 소개된다. 이 날갯짓 구동 장치는 끈을 이용하여 구조의 경량화와 관성력 감소로 인한 에너지 효율 상승을 목적으로 설계되 었다. 먼저 장력만 전달할 수 있는 끈의 특성을 고려하여 운동학적인 수식이 정립되었으며, 이를 통해 구동 장치의 거동 특 성을 파악할 수 있었다. 이 수식들은 수정된 패턴 검색 최적화 과정에 포함되어 메커니즘의 운동학적 최적화를 가능하게 만 들었다. 최적화된 형상으로 제작된 시제품은 설계의 구동 원리에 맞게 운동하였으며, 그 날갯짓 폭은 목표한 날갯짓 폭을 만 족시켰다. 수치적 시뮬레이션과 실험 결과는 잘 일치하여 제시된 구동 장치가 실제로 활용될 수 있음을 보였다.

In this study, H13 tool steel sculptures are built by a metal 3D printing process at various laser scan speeds. The properties of commercial H13 tool steel powders are confirmed for the metal 3D printing process used: powder bed fusion (PBF), which is a selective laser melting (SLM) process. Commercial H13 powder has an excellent flowability of 16.68 s/50 g with a Hausner ratio of 1.25 and a density of 7.68 g/cm3. The sculptures are built with dimensions of 10 × 10 × 10 mm3 in size using commercial H13 tool steel powder. The density measured by the Archimedes method is 7.64 g/cm3, similar to the powder density of 7.68 g/cm3. The hardness is measured by Rockwell hardness equipment 5 times to obtain a mean value of 54.28 HRC. The optimum process conditions in order to build the sculptures are a laser power of 90 W, a layer thickness of 25 μm, an overlap of 30%, and a laser scan speed of 200 mm/s.

This study presents a sustainable design method to optimize the embodied energy and CO2 emission complying with the design code for reinforced concrete column. The sustainable design method effectively achieves the minimization of the environmental load and energy consumption whereas the conventional design method has been mostly focused on the cost saving. Failure of reinforced concrete column exhibits compressive or tensile failure mode against an external force such as flexure and compression; thus, optimization analyses are conducted for both failure modes. For the given sections and reinforcement ratios, the optimized sections are determined by optimizing cost, embodied energy, and CO2 emission and various aspects of the sections are thoroughly investigated. The optimization analysis results show that 25% embodied energy and 55% CO2 emission can be approximately reduced by 10% increase in cost. In particular, the embodied energy and CO2 emission were more effectively reduced in the tensile failure mode rather than in the compressive failure mode. Consequently, it was proved that the sustainable design method effectively implements the concept of sustainable development in the design of reinforced concrete structure by optimizing embodied energy consumption and CO2 emission.

Purple-fleshed potato powder (PFPP) was investigated to determine optimal mixing ratio with milk powder and dextrin to produce a ready-to-eat mashed potato powder. The rheological characteristics, color, and anthocyanin contents were studied at a different concentration of ingredients. The power-law model was applied to explain the mechanical spectra of mashed potatoes which represented the change in structure induced by different mixing ratios. Mixture design was used to obtain the experimental points used to establish the empirical models to describe the effects of each ingredient on the characteristic of the mashed potato. The results of mechanical spectra showed that both storage and loss moduli (G' and G'') were significantly influenced by PFPP and milk powder concentration. The power law parameters n' and n'' showed higher values for the mashed potato with a lower concentration of PFPP and a higher concentration of milk powder, which showed that the gel networks involved in the mashed potato were weaker. The optimum mixing ratio with the highest redness and anthocyanin content, while maintaining the rheological properties similar to the commercial mashed potato, was determined as PFPP:milk powder:dextrin = 90.49:4.86:4.65 (w/w). The proportions of PFPP and milk powder in the formulation significantly changed the characteristics of mashed potato, whereas no significant effect of dextrin was observed in this formulation.

Purple-fleshed potato powder (PFPP) was investigated to determine optimal mixing ratio with milk powder and dextrin to produce a ready-to-eat mashed potato powder. The rheological characteristics, color, and anthocyanin contents were studied at a different concentration of ingredients. The power-law model was applied to explain the mechanical spectra of mashed potatoes which represented the change in structure induced by different mixing ratios. Mixture design was used to obtain the experimental points used to establish the empirical models to describe the effects of each ingredient on the characteristic of the mashed potato. The results of mechanical spectra showed that both storage and loss moduli (G' and G'') were significantly influenced by PFPP and milk powder concentration. The power law parameters n' and n'' showed higher values for the mashed potato with a lower concentration of PFPP and a higher concentration of milk powder, which showed that the gel networks involved in the mashed potato were weaker. The optimum mixing ratio with the highest redness and anthocyanin content, while maintaining the rheological properties similar to the commercial mashed potato, was determined as PFPP:milk powder:dextrin = 90.49:4.86:4.65 (w/w). The proportions of PFPP and milk powder in the formulation significantly changed the characteristics of mashed potato, whereas no significant effect of dextrin was observed in this formulation.