Membrane-Aerated Biofilm Reactor(MABR)는 하수처리 공정의 에너지 효율을 획기적으로 개선할 수 있는 차세대 기술로 주목받고 있다. 기존 활성슬러지 공정의 기포형 산기 시스템은 산소전달효율(OTE)이 낮고 전체 에너지 소비의 80%까지 차지하는 등 에너지 비효율성을 내포하고 있다. 반면 MABR은 기체 투과성 막(membrane)을 통해 생물막으로 산소를 직접 공급함으로써, 이론적으로 100%까지 OTE 달성이 가능하다. 본 논문은 MABR의 산소전달 메커니즘과 구조적 특징을 정리하고, OTE, 산소전달속도(OTR), 폭기 효율(AE) 등의 에너지 효율 지표를 중심으로 파일럿 및 실규모 적용 사례 11건을 분석하였다. 분석 결과, AE는 기존 활성슬러지 공정 대비 약 4-5배 향상된 수치이다. 그러나 OTE와 OTR 간의 상충관계, 공정 규모, 기질 농도 등 다양한 운영 변수에 따라 성능이 상이하게 나타났으며, 현장 적용에서는 이론적 효율을 하회하는 사례도 확인되었다. 이러한 한계를 극복하기 위한 기술적 접근으로는 간헐 공기 공급, 주기적 환기, 막 소재 개선, 막 이완 제어 등이 시도되고 있다. 동시에, 실증 연구들 간 실험 조건 및 효율 지표 산정 기준의 상이함은 결과 해석의 일관성을 저해하는 요인으로 지적된다. 따라서 본 연구는 향후 MABR 기술의 실용화를 위해 에너지 효율 평가 기준의 표준화와 대규모 현장 검증의 필요성을 강조한다.

This study compares and analyzes changes in users’ perceptions of industrial catering food service quality before and after COVID-19. The survey enrolled 226 subjects at five industrial catering establishments in Seoul and Gyeonggi Province; a total of 204 customers with complete data were included in the final analysis. Factor analysis was conducted to verify convergence validity and construct reliability; results pertaining to ‘service and environmental hygiene’ and ‘quality of food’ were extracted. Among the general variables of food service quality, differences were obtained in the user’s perceptions of food service qualities according to gender, education, and marital status. Our results revealed that women, low education, and married people perceived significant differences in all attributes before and after COVID-19. Additionally, varied altered perceptions were determined for service quality according to the occupations of the subjects. However, no differences were obtained for pleasant dining environment in the ‘service and environmental hygiene factor’ and variety of desserts in the ‘food quality factor’.

The study was aimed to investigate the operational meal costs by kindergarten size in Seoul and to analyze recognition for optimal meal prices. A survey (31.6% recovery rate) was conducted on all kindergartens (779 kindergartens) in Seoul on April 2021 using descriptive analysis, t-test, and dispersion method. A price sensitivity measurement (psm) method was used to determine optimal meal prices. Result showed an average food cost for kindergartens of 2,647 won, an average labor cost of 605 won, an average operating cost of 146 won, and the total meal cost of 3,506 won. Total meal cost decreased with increasing kindergarten size (p<0.001). On the other hand, kindergartens with more students decreased the ratio of food cost to total meal cost, and operating cost and labor costs (p<0.001) increased. The optimal price of kindergarten operators' meal cost (OPP) was KRW 3,673. Furthermore, the analysis showed the sensitivity of operators' meal costs to kindergarten size was insignificant.

The purpose of this study was to analyze the operators' perception of the allowable price range and the optimal price of kindergarten meals by using the PSM (price sensitivity measurement) technique and provide basic data on calculating kindergarten meal costs reflecting realistic meals. From April to May 2021, 779 kindergartens in Seoul were surveyed, based on 246 (31.6%) of the respondents. According to the survey, kindergarteners spent 3,506 won for meals on average, followed by 3,822 won for kindergarten attached to elementary school, 3,316 won for public kindergartens, and 2,896 won for private kindergartens (p<0.001). The allowed price range for the kindergarten meal service workers was estimated at 3,447~3854 won, 3,447 won for PMC (Point of Marginal Cheapness), and 3,854 won for PME (Point of Marginal Expensiveness). The appropriate cost of the kindergarten meal service provider was 3,950 won for kindergartens attached to elementary school, 3,425 won for public kindergartens, and 3,546 won for private kindergartens.

The purpose of this study was to investigate the perception of the quality of school meals by parents of kindergarten children in Seoul, analyze the acceptance price and the optimal school meal cost using PSM (price sensitivity measurement) techniques, and provide basic data for improving the quality of kindergarten meals. The survey was conducted using descriptive statistics and PSM analysis of the responses of 1,272 parents of 779 kindergarten children belonging to the Seoul Metropolitan Office of Education from April to May 2021 and prior research analysis related to kindergarten meals. 74.1% of the parents surveyed were women, with 61% of children attending kindergartens attached to elementary schools, followed by private kindergartens (28.9%) and public kindergartens (10.1%). According to a study of the quality of meals, private kindergarten parents are highly satisfied with all the quality attributes of meals, such as “sanitation of dining environment” and “nutritionally balanced food” (p<0.001, p<0.01). The analysis of the acceptance price range and the optimal price for school meals showed that there was no significant variation based on the type of kindergarten establishment, with parents' acceptance price range ranging from 3,596 won to 4,454 won with an optimal price of 3,948 won.

The objective of the current study was to compare the execution of hygiene and safety management according to the characteristics of children’s food service stations, with the ultimate objective of providing sanitary and safe food service to children. To this end, the study conducted surveys of 73 public and private pre-schools with fewer than 100 children in district A from July 30 to October 31 2015. The differences were evaluated by t-test and analysis of variance. The confidence and validity of the results were analyzed by six food ingredient and facilities management questions, three personal hygiene and facilities management questions, four environmental management questions, and five storage and treatment management questions; for a total of 18 questions. The cumulative distribution of the four factors was 61.569%, and the Cronbach’s alpha was 0.821, which indicated that the results were reliable. The results revealed that public pre-schools (a) and home-based pre-schools (b) had different levels of food ingredient and facility management, but no differences in the number of cooks, number of children served, type of food distribution, and the existence of mass food service facilities. The results of the study may be used to develop hygiene and safety management manual and educational contents to promote the health of the children served.

The current study was conducted to facilitate appropriate hygiene and safety management in children’s food service stations, with the ultimate objective of providing sanitary and safe food service to children. In order to develop questionnaire items, literature review was conducted, in addition to detailed interview of working-level personnel at a children’s food service management support center. This resulted in a total of thirty questions on personal hygiene management, food materials hygiene management, and facilities hygiene management. Using the questionnaire, seventy-one food service stations for children in District A in Seoul that serve less than one hundred children were surveyed to analyze the reliability, construct validity, and correlation in the developed measurement tool. The developed measurement tool consisted of ten task and environmental hygiene management questions, five personal and cooking hygiene management questions, four food ingredient and storage hygiene management questions, and four food service operation and management question; with a total of twenty-three questions, in four factors stated above. The cumulative distribution of the four factors was 54.698%, and Cronbach’s α value was 0.672~0.853, which indicated that the study was reliable. The results of the analysis indicated that each of the factors were correlated, the study was satisfactory, and the tool was valid for evaluating hygiene and safety management practices in children’s food service stations. Finally, in order to enhance practical utility of the developed measurement tool, the significance and limitations were described.

The goal of the current study was to analyze major factors for improvement of quality of life in contract foodservice customers. This study investigated how characteristics of customers, foodservice management, and competitors differ in different contract foodservice business environments in order to understand increasing concerns over health, in-house working, and the environment, which are directly connected to work and life satisfaction and company profits. For the foodservice business environment, this study classified environmental factors reported by Duncan (1972) into three factors: customer environment, foodservice management environment, and competitor environment. Multi-regression analysis was conducted on quality of life using the Korean version of the WHO Quality of Life Scale Abbreviated Version (WHOQOLBREF). Sub-factors of the contract foodservice business environment included foodservice management environment, customer environment, and competitor environment in the order of importance. The results indicate that the foodservice management environment of the company or organization where the customer is employed has the most substantial influence on quality of customer life.

The objective of the current study was to analyze the major factors affecting quality of life improvement for contract foodservice customers by identifying the contract foodservice environment consisting of the customer, foodservice management, and competitor. Qualitative research method was performed on foodservice customers and foodservice management using in-depth interviews. First, the customer environment was classified into three categories, including convenience of location, foodservice management environment into six categories, including comfort level of dining facility, and competitor environment into three categories, including service competition between foodservice providers. Second, quality of life was defined as the level of contentment felt by both the customer and foodservice management consuming the food provided. Third, both the customer and foodservice management perceived that the management environment of contract foodservice had a “medium” effect on quality of customer life. The findings of this study could be applicable for development of a contract foodservice business strategy through objective comparative analysis of the customer, foodservice management, and competitor environments.

In recent days, there is much interest in the biocidal activity of silver since silver is known to be safe and effective as disinfectant and biocidal material against bacteria and viruses. There is also increased interest in the nano-sized silver particles which can be used as effective bactericidal material. The purposes of this study were to investigate the effect of silverized elastomers on growth of oral pathogenic microorganisms, including Streptococcus mutans, Fusobacterium nucleatum, Porphyromonas gingivalis by comparing with conventional non-silverized elastomers. The antibacterial efficacy of silverized elastomer against oral pathogenic microbes was investigated by modified disk diffusion test and growth inhibition test. In modified disk diffusion test, silverized elastomer showed no antibacterial activity against S. mutans, F. nucleatum and P. gingivalis, In culture medium, the growth of S. mutans, F. nucleatum, P. gingivalis was not inhibited by silverized elastomer. Silverized elastomer exhibited no bacteriostatic and/or bacteriocidal effects against some experimental strain.nd clinical indications and diseases.

This research analyzed the naming standard of Korea menu names divided into two groups, main dish and side dish. The research was conducted by contents analysis of selected literature articles and multiple-response cross tabulation analysis. The result demonstrated that the naming standard of Korea food consisted of the main ingredient name - sub ingredient name - main condiment name and main recipe. On the other hand, the menu name that is in native language or has a historical origin is exempt from this classification. Therefore, this study proposes a new standard, 'Hansik Menu Naming', to assist the food service industry and correct the names of unknown foreign dishes.

제주도는 현무암과 조면암으로부터 기원한 투수성 높은 토양으로 인하여 지표수 유입에 따른 상시하천 발달이 어려워, 용수의 대부분을 지하수에 의존하고 있다. 이에 따른 무분별한 지하수 개발은 지하수위 강하로 이어져, 제주도내 많은 지역에서 지하수 오염과 해수침투 현상이 나타나고 있다. 제주특별자치도는 제주도의 항구적인 지하수자원 보전을 위하여 1994년 이래 일부 지역을 지하수 보전구역으로 지정하였으며, 이 지역내의 모든 지하수 개발은 허가를 받도록 지정한 바 있다. 또한 지하수 수문과 관련된 수리지질 정보 획득을 위하여, 2001년 이래로 제주도 내 해안지역 및 저지대 전체를 대상으로 지하수 관측망을 설치 운영 중이다. 본 연구에서 이러한 지하수 관측망으로부터 얻어진 지하수위, 수온, 전기전도도 등 장기 관측자료를 분석한 결과, 북부 해안지역의 경우 지하수위가 지속적으로 하강하는 것으로 나타났다. 또한 동부 해안지역의 경우는 최근 취수량의 급격한 증가에 따른 해수침투의 영향으로, 대부분의 관측정에서 전기전도도가 높게 나타나며 지속적으로 증가하고 있는 추세로 분석되었다. 이러한 문제점들은 지하수 개발과 관련하여 제주특별자치도의 강력한 통제로 인하여 최근들어 감소하는 추세이지만, 본 연구 결과에 의하면 해안지역의 경우에는 지하수위 하강 및 전기전도도 상승 현상이 지속될 것으로 판단된다.

우리나라 서, 남해안에 지하수의 해수침투 현상을 관측하기 위해 설치된 관측망 자료를 이용하여, 해당지역별 대수층을 통한 해수침투의 유형을 분석하였다. 분석에 이용된 관측정은 25개 해안지역 소유역의 총 45개 암반관정으로, 지하수위, 수온, 전기전도도를 대상으로 기본통계분석, 상관성 분석 및 변동유형 분류를 수행하였다. 분석 결과 지하수위의 경우 강우 영향을 받거나 양수에 의한 수위강하가 나타나는 관측정에서 큰 폭으로 변동하고 있다. 지하수온은 대부분의 경우 변동폭이 0.2˚C 이내로 안정적인 특징을 보여주고 있으며, 전체적으로 평균 온도가 15˚C 이상으로 나타났다. 전기전도도의 경우 상대적으로 변동폭이 크고 불규칙한 특징을 가지고 있으며, 평균값이 2,000 μS/cm 이내의 관측정이 28개, 10,000 μS/cm를 초과하는 관측정은 9개소로 나타났다. 교차상관도 분석에 의하면, 지하수위는 강우의 영향을 받아 변동하는 형태가 많았지만 수온과 전기전도도는 상대적으로 강우의 영향이 없는 것으로 나타났다. 조석의 경우에는 일부 관측정에서 강우에 의한 영향보다 높은 교차상관도가 나타났다. 본 연구에서는 장기관측자료를 변동형태에 따라 정상형, 추세형, 주기형, 충동형, 계단형, 경사형 등 6가지로 분류하였다. 지하수위의 경우 강우나 양수의 영향을 받는 충동형이 가장 많은 73.3%이며, 조석의 영향은 13.4%에 해당되었다. 지하수온의 경우 변동폭이 일정한 정상형태가 51.2로 가장 높게 나타났으며, 강우나 양수에 의한 충동형이 26.7%에 해당되었다. 전기전도도의 경우는 지하수위나 지하수온과 달리 추세형, 계단형, 경사형 등의 변동형태가 우세한 것으로 나타났다. 전체적으로 동일한 해안지역에 설치된 관측정별로 관측자료의 변동 특성이 상이한 경우가 나타남에 따라, 향후 각 소유역별로 관측정 자료의 정기적인 변동 경향성을 분석하는 것이 필요하다.

2003년도에 추가된 85점의 고추 유전자원에 대하여 역병에 대한 저항성을 검정한 결과 새로운 고도 저항성 재료는 발견되지 않았다. 그러나 재래종의 원예적 형질을 갖춘 KC1184가 중도의 저항성을 나타내어 활용가치가 있을 것으로 사료되었다.

본 논문에서는 정속마찰 시험기를 사용하여 공기중에서 핏치/CVI계와 페놀/CVI계 낱소/탄소 복합재료의 마찰특성을 평가하고 상호 비교하였다. 운용조건(마찰거리, 마찰속도, 마찰압력)에 관계없이 페놀/CVI계의 평균 마찰계수가 핏치/CVI계 보다 높은 값을 나타내었다. 마찰거리가 4Km이하 일때는 평균 마찰계수가 불안정한 경향을 나타내고 그 이후에서는 안정한 평균 마찰계수 값을 갖는다. 또한 마찰속도와 마찰압력이 증가할수록 평균 마찰계수는 감소하는 경향을 나타내며, 페놀/CVI계의 평균 마찰계수가 핏치/CVI계 보다 높고 마찰면 온도 상승률과 최대 마찰면 온도도 높다. 마찰계수는 마찰면 온도의 영향을 받으며, 마찰속도와 3kg/cm2이하에서 마찰압력이 커질수록 최대 마찰계수를 갖는 마찰면 온도는 높아진다.