• Journal of Korea Foundry Society
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• v.41 no.6
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• pp.543-549
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• 2021

Aluminum cast iron has excellent oxidation resistance and good resistance to sulfide and corrosion. Compared to Ti and Ni alloys, it is expected to be a substitute material for structural materials and stainless steels because it is relatively inexpensive to use Fe, which is a non-strategic element. This results in a weight reduction effect of about 30% as compared to the use of stainless steel. With regard to aluminum as an alloying material, it is an element that has been widely used for the alloying of cast iron in recent years. Practical use has been delayed owing to the resulting lack of ductility at room temperature and the sharp decrease in the strength above 600℃ of this alloy, however. The cause of the weak room temperature ductility is known to be environmental embrittlement by hydrogen, and the addition of various alloying elements has been attempted in order to mitigate these shortcomings. Although alloying elements such as vanadium, chromium, and manganese are mainly used to increase the hardness and wear resistance of gray cast iron, the price of finished products containing these elements and the problems associated with alloys with this material impose many limitations.

• Journal of the Korean GEO-environmental Society
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• v.23 no.7
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• pp.5-10
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• 2022

The industrial waste is becoming a big problem in the aspect of spatial and environmental in domestic and international. Therefore, the waste reduction and recycling policy has been being implemented as a way to solve this problem. The engineered stone sludge, which is waste, is generated duing the engineered stone production process. since engineered stone sludge is mostly treated by landfill, an increase in the amount of the sludge leads to an increase in landfill sites and treatment costs. therefore, there is a need for a method of resourcization with engineered stone sludge. So, laboratory tests (Plastic and liquid limits, compaction, unconfined compression and permeability test) were conducted to confirm the possibility of using engineered stone sludge mixed with weathered granite soil as a cover material for landfill in this study. The result shows that the mixed soil material with less that 62.5% of engineered stone sludge can be used as a cover material for landfill.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.111-116
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• 2022

The causes of motor burnout include overload, phase loss, restraint, interlayer short circuit, winding ground fault, instantaneous overvoltage, and the rotor contacting the stator, leading to insulation breakdown, leading to breakdown or electrical accidents. Therefore, equipment failure causes not only loss due to cost required for equipment maintenance/repair, but also huge economic loss due to productivity decrease due to process stop because the process itself including the motor is stopped. The current level of technology for diagnosing motor failures uses vibration, heat, and power analysis methods, but there is a limit to analyzing the problems only after a considerable amount of time has passed according to the failure. Therefore, in this paper, a device and algorithm for measuring insulation resistance using DC AMP signal was applied to an industrial motor to solve this problem. And by following the insulation resistance state value, we propose a diagnosis of deterioration and failure of the motor that cannot be solved by the existing method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.802-807
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• 2022

In projects where mufti-project management is required and processes for production activities are repeated and linked, it is very difficult to input processes for activity repeatedly or analyze loads by process in a method of managing processes step by step. In this paper, based on the definition of activity and project process, the connection process can be automatically created for activity, schedule and resource management for each process, schedule and resource plan can be established for each detailed process, and load analysis can be provided in real time. It presents a project management system that can significantly improve the time and cost of project progress management, predict various problems that may occur during the project, and effectively allocate the necessary amount of resources in the right place.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.839-856
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• 2022

Over the last decade, the competition for space development has accelerated. The world's largest space agencies are aiming toward long-term lunar exploration and manned missions. For sustainable and safe lunar exploration, construction of infrastructures that include various habitats is essential. However, transporting construction materials from Earth for lunar base construction is extremely expensive. Thus, technologies for manufacturing construction materials using in-situ resources from the moon should be advanced. The sintering techniques have been actively studied using lunar soil. In this review, five sintering technologies, including radiation, solar, spark plasma, laser, and microwave sintering, for manufacturing construction materials using lunar soil are introduced, and future research is discussed.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.33 no.3
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• pp.179-203
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• 2022

This study purposed to measure the economic value of repository services of the National Open Access Platform (AccessON), namely Self Archiving and Journal Repository. The value of Self Archiving was measured by applying time-saving value and the value of Journal Repositories by applying market analogy. Based on existing statistics, in-depth interviews with service beneficiaries and stakeholders, and a survey administered to 1,313 researchers, the value of Self Archiving was estimated to be 145 million won and an additional 12 million won with the OA legalization. The value of Journal Repositories was estimated to be 31.2 billion won. The total value of the repository services was 31.35 billion won over the 8-year business period. This result presented an estimated economic value of a national OA repository from the key beneficiaries' perspectives.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.31 no.6
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• pp.35-39
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• 2002

최근, 산업의 발달로 인하여 생활수준이 향상되어 대량생산과 대량소비현상이 발생하고 도시의 밀집도가 높아 단위 면적당 거주하는 인구가 증가되면서 거주지역에서 발생되는 부산물이 현저히 증가되어 환경측면에서 복합적인 환경문제에 직면해 있다. 최근까지 대책마련에 고심하고 있는 도시에서 발생된 다량의 쓰레기 처리문제는 경제적인 측면에서 몇 년 전 까지는 대부분을 매립에 의존해 왔으나, 매립 방식에 의존하였으나 지가 및 공사설비의 상승, 일부 비위생적으로 조성된 매립장에서 배출되는 침출수 및 악취 등의 환경오염이 심각한 사회문제로 대두되면서 매립장의 확보나 증설은 해당 지역주민의 반발로 지방자치단체의 골치 아픈 과제로 등장하였다. 이러한 문제점을 보완하기 위해, 최근에는 매립지 확보의 어려움과 환경보존을 위하여 쓰레기를 정적이고 위생적으로 처리하기 위하여, 소각시설이 표 1과 같이 증가하고 있으나 소각 때 발생하는 다이옥신 등 인체에 치명적인 오염을 유발시키기 때문에 소각로 건설에 대한 환경운동단체와 주민들의 반발이 거세게 제기되고 있는 현실이다. 이러한 영향에 의해 앞으로는 소각보다는 쓰레기 자체를 감량.재사용.재활용하는 처리방식이 표 1과 같이 증가되는 현실이다. 쓰레기를 소각하는 것은 제 2오염을 유발시키고, 소각장 건설비용과 유지관리에 많은 예산이 소요된다. 쓰레기소각장을 건설할 때, 인근주민이나 환경단체로부터 반대의견에 직면하게 되는데, 그 사유는 쓰레기 처리과정의 전 단계인 반입.공급 과정에서 악취발생과, 후단계인 소각설비에서 발생되는 배출가스 오염원을 완전히 제거하라는 것이다. 최근에는 소각장의 설계.시공과정에서 최대한 악취발생과 확산을 억제하는 시설에 투자를 하고 있으며, 또한 주민 편익 시설과 부대 복리 후생시설은 소각시설 주변지역 주민틀의 소각시설에 대한 부정적 이미지를 불식시키며, 외부 방문객이나 운영 관리 요원들에게 쾌적한 환경조성과 업무효율 및 근무환경의 개선에 일익을 담당하고 있다. 본 고는 환경 친화적인 쓰레기 소각장을 설계하는 측면에서 1998년도에 턴키방식으로 발주되었고 2001년 12월에 준공하여 운전하고 있는 경기도 구리시 자원회수시설의 환기설비에 적용된 설계 및 시공개념을 소개하고자 한다.

• Journal of Life Science
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• v.33 no.1
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• pp.82-90
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• 2023

Biological process is used worldwide to treat domestic and industrial wastewater. The process generally uses a mixed microbial culture of sludge. The growth of microorganisms in the sludge produces excess sludge from the wastewater treatment process. Some of the excess sludge is recycled as inoculum for wastewater treatment, but the rest is removed as waste from the process. As wastewater production is increasing worldwide every year, the number of wastewater treatment plants (WWTPs) is also in- creasing, resulting in the generation of large amount of waste sludge. The increasing amount of waste sludge from WWTPs has led to concerns about its management. Sludge disposal has been reported to account for 50~60% of the total operating costs of a WWTP. Sludge disintegration is a new technology that can minimize volume of waste sludge and recover useful components (e.g., P, N, and soluble organic compounds) from it. Various methods of sludge disintegration have been developed based on physical, chemical, and biological treatments or combinations of these. In this review, we focus on sludge disintegration by acid hydrolysis, which is less studied among sludge disintegration methods. Such information can be useful in the development and implementation of a new technology for better sludge treatment.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.661-668
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• 2023

A large amount of fuel is required for heating the agricultural facility house, and many farmhouses are experiencing the burden of heating costs due to the recent increase in fuel prices. This paper proposes a supply system that supports heating of agricultural facility houses located nearby by utilizing industrial chimney waste heat, and analyzes the application and effect of a heating cost reduction model. The system was designed based on the chimney waste heat system, and the facility house heating cost reduction model was applied and effect analysis was performed based on the proposed model. It was confirmed that the high-temperature waste heat from the chimney can be used to supply heating to facility houses in nearby farms. If heating is supplied to large-scale facility houses near industrial complexes, it is expected to contribute to improve productivity and competitiveness of domestic farms.

• Journal of Practical Agriculture & Fisheries Research
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• v.14 no.1
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• pp.195-209
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• 2012

1) 버섯종균 생산 시스템 개선 버섯의 품질과 수량을 좌우하는 주요 요인은 종균의 활력이다. 그러나 말라위에서는 종균의 활력이 낮아 조그마한 350cc 음료수 병에 배양 완성하는데 20일이 소요되는 등 노동력의 비효율성을 개선하였다. 따라서 350cc 병을 3500cc 비닐봉지로 개선하여 입봉하는데 소요되는 시간을 10배 이상으로 단축 개선하였다. 또한 곡립종균을 액체종균으로 대처한 결과 균사생장 속도가 빨랐으며 작업속도가 빨라졌다. 곡립 수수를 밀로 대체하여 종균제조 노동력을 효율적으로 전환하였다. 2) 버섯재배사 환경관리 개선 버섯재배의 4대 환경조건은 온도, 습도, 환기, 광이다. 그러나 말라위의 버섯재배사는 4대 환경조건 조절을 자연상태에 의존하고 있다. 그럼에도 불구하고 비닐로 커버된 상태에서 문을 닫아두어 과습이 되고 환기가 되지않았다. 이를 개선하기 위하여 직경 5cm 환기공을 버섯재배사 당 4개씩 만들도록 지도하였다. 3) 버섯배지 개선 말라위에서는 옥수수 대를 잘라 버섯배지로 주로 이용하고 있다. 이를 개선하여 말라위 북부지역(다광)에 대규모 사탕수수 공장을 방문하여 사탕수수 박을 이용하여 버섯재배 기술을 교육하였다. 이를 이용함으로서 버섯 균사생장속도를 빠르게 하고 균사량의 축적을 높이도록 하여 고품질 다수확하는데 교육을 하고 컨설팅을 실시하여 개선하였다. 4) 버섯 배지 야외발효 후 지면재배 시도로 시간 단축과 비용절감 말라위 버섯배지 혼합제조법은 옥수수대 한가지로서 영양원이 없다. 이를 개선하여 배지를 수분을 흡수시킨 후 야외 퇴적하므로서 배지의 물리성을 개선하고 야외발효 과정 중 양분이 합성되어 양질의 배지를 만드는 방법이다. 야외발효한 배지를 봉지에 담아 균상에 입상하는 불편함과 나무로 만들어진 균상대의 과습으로 인한 곰팡이 발생과 개미 침입으로 썩는 것 등을 방지하기 위하여 지면재배 방법으로 개선하였다. 이 지면재배는 균상 만드는 나무재료와 인건비 절감. 병해충 발생 방제 뿐만아니라 고품질 다수확할 수 있는 방법으로 개선 교육과 시범 시연을 실시하였다.