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        검색결과 164

        21.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The degree and intensity of unpleasant and disgusting odors perceived through a person's sense of smell can vary depending on personal or social and cultural characteristics. In addition, it is not effective to manage odors solely on the basis of concentration levels because odors can be combined according to temperature, humidity, and frequency, so that they can be recognized differently even if the same person smells the same substance. The mobile odor application was developed to enable real time monitoring of odor characteristics reflecting the actual condition of the field. Accordingly, the Green Future Foundation, a civic group, conducted an environmental campaign to record and share the information of odors in school zone using the first version of the application. The real time monitoring of field odor was able to improve the problems of the current standard methods for the examination and assessment of odors. However, with regard to the first version of the application, the process and results of odor recording through odor measurement applied the direct olfactory method and were less relevant. Therefore, it was difficult to organize data due to duplicate selection. For that reason, this study was conducted to overcome the problems of the first version of the mobile application and to effectively and accurately reflect odors and personal characteristics. This odor application that has been developed is able to monitor and assess odors based on 5 features: classification, character, strength level, hedonic tone, and acceptability.
        4,000원
        23.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Valves are widely used in various industrial fields, such as plants, vessels and shipbuilding. In particular, the performance of the valve is an important factor that can influence the performance of the entire system. Therefore, in this basic study to establish a national technical qualification in the domestic field of valve maintenance, demands for the fields of valves and major congruence were analyzed focusing on the industrial facility curriculum of Korea Polytechnics, and level-differentiated trial examinations were applied to relevant majors to standardize the developed valve tester. The trial examination result displayed that in the highest level of difficulty, in the medium level of difficulty and in the lowest level of difficulty, the pass rate was 0%, 17.86% and 39.29% respectively.
        4,000원
        28.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We used three gas sensors to monitor hydrogen sulfide, ammonia, and volatile organic compounds (VOCs), which were frequently emitted from environmental facilities, such as municipal wastewater treatment, livestock manure treatment, and food waste composting facilities. Two electrochemical (EC) sensors for detecting hydrogen sulfide and ammonia, and a photoionization detector (PID) sensor for detecting VOCs were characterized in this study. The performance of their linearity by concentration levels, lower detection limit (LDL), repeatability, reproducibility, precision, and response time were tested under the laboratory condition. The linearity according to concentration levels were favorable for all three sensors with high correlation coefficients (R2 > 0.98). The ammonia sensor showed the highest LDL (18.6 ppb) and the hydrogen sulfide and VOC sensors showed 22.3 ppb and 26.7 ppb of LDL, respectively. The reproducibility and precision were favorable for all three sensors, indicating a lower relative standard deviation (RSD) than 0.9% in the reproducibility test and 7.2% in the precision test. The response times to reach target concentration were varied from 1 to 12 minutes. The ammonia sensor needed 12 minutes of response time at 1 ppm target the NH3 concentration and the hydrogen sulfide and VOC sensors needed less than 2 minutes of response time.
        4,200원
        29.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Most of aged water supply pipes have been replaced by the open cut method. However, this method has some limitations because water pipes, in many cases, are buried together with other underground facilities or are buried in the middle of high-traffic roads or in narrow alleyways where boring machines cannot be used. This research developed a pipe bursting device for small diameter pipes that enables pipe replacement without excavating the ground, by the busting of existing buried pipes followed by the traction and insertion of new pipes. As a results of examining the field applicability of the developed device, PE pipes and PVC pipes required the tractive force of 413.65~665.69 kgf and 457.43~791.35 kgf respectively, plus an additional 30 % tractive force per elbow. The proper number of bursting head was demonstrated that the connection of more than 2 heads could secure a stable bending radius of 15D. The developed device can be improved through field experiments involving various pipe types and pipe diameters, as well as presence/absence of elbow, so as to be utilized regardless of diverse variables according to the conditions of the soils surrounding existing pipes.
        4,000원
        30.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        파이로 공정에서는 사용후핵연료 관리 공정 개발의 일환으로 산화 우라늄을 고온 용융염 전해질계에서 전기화학적 방법으로 환원시키기 위한 전해환원 공정이 개발되고 있다. 이에 따른 전해환원 공정의 반응기 설계를 위해서는 전기화학적 이론에 기초한 모델이 요구되고 있다. 본 연구에서는 상 분리를 설명하는 phase-field 이론에 기초하여 우라늄 산화물의 전해환원 모사를 위한 1차원 모델이 개발되었다. 모델은 우라늄 산화물 내 산소 원소의 확산과 펠렛 표면에서 전기화학 반응 속도를 나타내는 매개변수를 사용하여 외부로부터 내부로 진행되는 전해환원을 잘 모사하고 있으며 계산 결과 전체 전류는 산소 원소의 내부 확산에 크게 의존하는 것으로 나타났다. 전해환원 반응에 대한 모델은 대용량 장치 설계에 최적화된 조건 도출에 활용될 것으로 예상되며 장치 설계가 완료되면 공정 연계 모사에 직접 사용될 것으로 기대된다.
        4,000원
        31.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        교미교란(mating disruption, MD) 기술이 사과에 피해를 주는 복숭아순나방(Grapholita molesta) 방제에 널리 사용되고 있다. 복숭아순 나방과 복숭아순나방붙이를 동시에 교미교란(simultaneous MD, SMD)하는 기술이 최근에 개발되었다. 본 연구는 이 SMD 기술을 현장에 접목하는 데 필요한 요인들을 결정하기 위해 수행되었다. SMD 처리 농도를 결정하기 위해 각 처리 지점에 10 mg의 성페로몬을 여러 가지 밀도로 사과나무에 처리하였다. 처리된 세 농도 가운데 두 나무마다 하나의 SMD 처리가 비교적 안정적으로 MD 효과를 유지하였다. 이러한 SMD 효과는 왁스 및 polyethylene 제형 모두에서 나타났다. 두 사과나무마다 하나의 SMD 처리 농도로 3월 말에 1회 처리한 경우 수확기까지 복숭아순 나방과 복숭아순나방붙이에 대해 효과적 교미교란을 유지시켰다. 인근 무처리 과수원에서 SMD 처리 과수원으로 이주하여 들어오는 교미된 암컷의 이입을 막기 위해 울타리 처리 기술이 적용되었다. 암컷 유인제를 개발하기 위해 6종류의 사과 과실 추출물에 포함된 화합물 가운데 terpinyl acetate (TA)가 선발되었다. 서로 다른 TA 농도 처리에서 0.05%가 성충 유인에 가장 효과적이었다. TA와 설탕을 혼합한 것을 암컷유살제(female attract-to-kill technique, FAKT)라 명명하였다. 사과 과수원 가장자리를 따라 6 m 간격으로 FAKT를 설치한 울타리 처리는 교 미된 암컷을 포획하였고, 이들은 난황형성과정을 진행하고 있는 난모세포를 지니고 있었다. FAKT가 가미된 SMD 처리는 높은 MD 효율을 유지하는 것은 물론이고 SMD 단독 처리에 비해 신초 피해를 현격하게 줄였다.
        4,300원
        32.
        2018.05 구독 인증기관·개인회원 무료
        Recently, Cambodia has been investing a lot of money in the construction and maintenance of roads, which are social infrastructures. However, damage to the existing pavement is accelerating due to the old age of the road pavement, poor drainage facilities and increase in heavy traffic. To solve this problem, a fundamental solution such as a high-performance asphalt mixture is required to extend the life of road pavement. In this study, a high performance glass fiber reinforced asphalt mixture developed in Korea was applied to Cambodia. Prior to field application, Marshall stability tests were performed on glass fiber reinforced asphalt mixtures, SBS modified asphalt mixtures and asphalt mixtures commonly used in Cambodia. The Marshall stability test showed that the glass fiber reinforced asphalt mixture and the SBS modified asphalt mixture had the same strength (about 1.3 times higher strength than the usual asphalt mixture). In addition, the test construction was carried out on the National Highway 2 of Cambodia for the evaluation of the performance of the three mixtures. In the future, the long-term performance evaluation of each mixture will be conducted through follow-up survey of the test construction area.
        33.
        2018.05 구독 인증기관·개인회원 무료
        The current construction and maintenance guidelines applied to airport pavement in Korea are those of the International Civil Aviation Organization (ICAO), the International Air Transport Association (IATA), and the Federal Aviation Administration (FAA). In order to consider local conditions of airports in Korea, more specific details should be addressed in those guidelines. For example, the design and construction for pavements at airports in Korea follow the specifications of materials for general roads or foreign airport pavement guidelines, as there is no design manual or guideline for the granular base and subbase materials for airport pavement in Korea. In such circumstances, the likelihood of premature failure or accelerated damage increases, as the loading from airplanes is not fully taken into account or the local environmental characteristics are not considered. In addition, concerns in public facility drainage systems have been rising recently in line with the increase in the frequency and scale, caused by the global abnormal-temperature phenomenon, of localized torrential rain and snow. For airport runways, measures to maintain swift drainage systems are especially necessary to ensure safety and prevent flight delays. In this study, the appropriate moisture content and pavement method are analyzed by applying porous concrete developed for a cement-treated base course for securing permeability of airport pavement at an actual construction site. In addition, on-site construction testing was performed to determine the appropriate compaction method and the curing method to minimize cracking by using a compaction facility. To determine the optimal moisture content, a quality-control was performed by measuring the moisture content of porous concrete produced at a batch plant. For this purpose, a speed moisture test (ASTM D 4944) was performed on site because the unit-water content of the porous concrete affects its compaction and finishing. Before compaction, a grader was used to remove fragments on the subbase and then a tandem roller was used to level and compact. After compaction, the porous cement-treated base course, called porous concrete, was placed using an asphalt finisher. The mechanical properties and durability of the porous cement-treated base course with a variation of a degree of compaction: noncompaction, tandem roller moved back and forth once, three times, and five times. The pavement was covered with vinyl according to the curing guidelines suggested by the Korea Expressway Corporation’s highway construction specifications, to prevent evaporation from porous concrete that has relatively low moisture content. After curing, the core was collected to analyze the compressive strength, permeability coefficient, porosity, and freeze–thaw resistance characteristics.
        34.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 야외지질답사 장소를 개발하고 과학적 모델의 사회적 구성을 야외지질학습에 적용하는 것이다. Orion(1993)의 가상의 공간(Novelty Space)과 2015 개정 교육과정 성취기준을 고려하고 답사 장소를 개발하였다. G 영재 교육원 과학과 8명 학생을 대상으로 ‘관악산 형성과정’이라는 것을 주제로 하여 총 5차시 분량의 과학적 모델의 사회적 구성을 활용한 야외지질학습을 실시하였다. 야외지질학습 전후로 1차시 분량의 설문 검사를 통해 학생들의 개념 이해 정도를 파악하고, 심층 면담에서는 개념 확인과 야외지질학습의 정의적인 면을 다루었다. 연구 결과는 다음과 같다. 첫 번째, 야외 답사 장소는 계곡 하류와 상류로 각각 명명하였고 변성암, 화강암, 절리, 포획암, 광물 입자를 관찰하도록 구성하였다. 두 번째, 사전 조사에서 관악산은 화산으로 만들어졌다고 응답한 학생이 7명이었다. 반면, 야외지질학습이 종료된 이후에는 7명 학생이 화강암의 형성과정을 설명하고 변성암을 예시로 지질시대를 이야기 하는 것으로 시간적인 스케일을 이해했음을 보여주었다. 더욱이 심층면담에서 지질학에 대한 낮은 성취를 보여주는 학생이 야외지질학습에 대해 긍정적인 답변을 주었다. 즉, 학습의 정의적인 면을 고려하였을 때 야외지질학습에 과학적 모델의 사회적 구성 활용이 효과적일 수 있다는 것을 보여준다. 이번 연구는 지질교육에 모델을 적용한 사례이고 동시에 교사에게 야외답사 장소를 제공할 수 있을 뿐만 아니라 야외지질학습에 과학적 모델의 사회적 구성을 적용한 사례로서 의의가 있다.
        4,800원
        35.
        2018.04 구독 인증기관·개인회원 무료
        This paper reviews on nano-materials as part of a study to apply nano-technology related technologies to the construction field. First, the synthesis method of nano-materials was examined. Secondly, the mechanical application method of nano-materials was investigated. Finally, the analysis method of nano-materials was investigated.
        36.
        2018.04 구독 인증기관·개인회원 무료
        소나무재선충은 북미가 원산으로 일본, 중국, 한국을 비롯한 동북아시아의 소나무류에 막대한 피해를 주고 있으며 포르투칼과 스페인에도 발생하여 유럽 소나무류에도 큰 위협이 되고 있다. 소나무재선충은 매개충인 Monochamus속에 의해 새로운 기주로 옮겨지기 때문에 매개충을 방제하는 것이 가장 중요하다. 국내 소나무재선충 매개충은 솔수염하늘 소와 북방수염하늘소가 보고되어 있으며 이들을 방제하기 위하여 주로 유기합성농약을 항공 살포하거나 연막기를 이용하여 살포하고 있다. 하지만 유기합성농약의 대면적 살포는 산림생태계에 큰 위협요인이 되고 있다. 본 발표에서는 유기합성농약을 대체하기 위하여 소나무재선충 매개충의 집합-성페로몬 및 카이로몬 연구 그리고 이들 유인제의 현장적용 연구 및 추후 연구방향에 대해 소개를 하고자 한다.
        37.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the corrugated steel pipes has many advantages to compensate for the shortcomings of the concrete fume pipes, it has been widely used for culverts and drain trenches. However, when corrugated steel pipes used as a sewage pipe or in an environment exposed to sea water, corrosion can cause problems and degradation of the function of pipe. So, Composite Corrugated Steel Pipe(CCSP) coated with three layers were developed to compensate for the shortcomings and improve performance of corrugated steel pipes. The composite material used in fabrication of the CCSP consists of a three layer polymer protective coating on both sides of a steel sheet core. To verify the field application of the CCSP, a test was conducted on the resistance of the strain, stability of connections, water flow performance and durability to determine whether they meet KS quality and various design standards.
        4,000원
        38.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a new method for solving an inverse problem of flux emergence which transports subsurface magnetic flux from an inaccessible interior to the surface where magnetic structures may be observed to form, such as solar active regions. To make a quantitative evaluation of magnetic structures having various characteristics, we derive physical properties of subsurface magnetic field that characterize those structures formed through flux emergence. The derivation is performed by inversion from an evolutionary relation between two observables obtained at the surface, emerged magnetic flux and injected magnetic helicity, the former of which provides scale information while the latter represents the configuration of magnetic field.
        4,000원
        39.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract It has come to attention that a risk-assessing organization, that will benchmark a company’s safety department, is imperative, following an increase in large-scale SOC-business project, construction of higher-raised buildings, development of underground space; all that have increase accident rates. Having faced problems that arise in firms that demand diversity, complexity and instantaneity, the purpose of the thesis is to arrive at efficient and practical problem-solving means. In order to solve the problems that would surface theoretically during an actual risk assessment, the state of the operation systems of the top five national construction firms having a hazard rate of 0.25 times less than the average rate have been analyzed, while a hierarchal recognition research of the employees who not only function at the operating level but are the practice subjects of a firm, has also been conducted, bringing the main text.
        4,000원
        40.
        2017.10 구독 인증기관·개인회원 무료
        The hawthorn spider mite, Amphitetranychus viennensis (Zacher), is an important tetranychid causing damage on fruittrees and woody ornamental plants. We investigated the effect of a mycoinsecticide BotaniGard® ES at different humiditylevels on the eggs and adults mortality of A. viennensis. In a laboratory condition, egg mortality was significantly influencedby the conidial concentration and RHs. Highest mortality of eggs was observed at 1×108 conidia/ml with 95% RH thanother conditions. In 1×108 conidia/ml, LT50 at 95 and 75% RH were significantly different from 55% RH. In BotaniGard®spray in cherry plants, mites decreased on day 6 at all the concentrations, but the mite populations rebounded exceptin 1×109 conidia/ml where it maintained 0 until 9 days after spraying. It is therefore concluded that B. bassiana hasa potential to be used against A. viennensis
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