• 제목/요약/키워드: Key Recovery System

검색결과 123건 처리시간 0.023초

산지은행제도의 도입방안에 관한 연구 (A study on the Introduction Plans of Forest Land Bank System)

  • 김종호;김원경;권순덕
    • 한국산림과학회지
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    • 제104권3호
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    • pp.503-511
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    • 2015
  • 본 연구의 목적은 효율적인 산림경영과 고령산주의 생활안정지원을 위한 산지은행제도의 도입방안을 제시하는 것이다. 산지은행제도는 분산된 소규모 산림, 산주의 고령화 및 부재산주 증가 등의 문제점을 해결하는데 도움을 줄 것으로 기대하고 있다. 본 연구에서는 기존의 유사제도인 농지은행제도의 사업에 대한 검토 및 비교를 토대로 산지은행제도의 개념 및 기본방향, 산지은행의 주요기능 및 사업종류와 범위 설정, 산지은행제도 도입 우선순위 등에 대해서 제안하였다. 산지은행의 주요 사업으로는 산지를 수탁 받아 산주 등에게 중개 알선하는 산지임대차 및 매도수탁사업, 고령 산주의 안정된 노후생활 보장을 위한 산지연금사업, 소규모로 분산된 사유림을 규모화 집단화하여 사유림 경영을 활성화하고 지속가능한 산림경영을 유도하기 위한 산지규모화사업, 경영위기에 처한 임가의 경영회생을 지원하기 위한 경영회생지원사업의 도입을 제안하였다. 마지막으로 산지은행제도 도입 및 사업운영을 위한 문제점과 시행착오를 최소화할 수 있도록 농지은행제도를 통한 시사점과 산지은행제도 도입 및 운영 시 제기될 수 있는 주요 과제에 대해서 검토하였다. 본 연구는 산지은행제도의 기본방향을 설정하고 정책을 수립하는데 크게 기여할 것으로 기대한다.

발효·소멸 기술을 이용한 음식물 쓰레기 무배출 시스템에 대한 공동주택 거주자의 태도에 관한 분석 (Exploring Residents' Attitudes in Multifamily Housing Toward Food Waste Zero-Emission System with Fermentation and Extinction Technology)

  • 오정익;이현정
    • 대한환경공학회지
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    • 제35권5호
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    • pp.321-333
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    • 2013
  • 주택 내에서 발생하는 음식물 쓰레기의 실태를 조사하고, 음식물 쓰레기의 자원화와 바이오처리를 이용한 음식물 쓰레기 무배출 시스템에 대한 거주자의 태도를 조사하는 본 연구에서는 전국 소재의 공동주택 단지 총 400세대를 대상으로 설문조사를 실시하였다. 가설검정을 위하여 SPSS window version 18.0 통계분석 프로그램을 사용하여 빈도 및 백분율, t-검정, ANOVA, 요인분석, 로지스틱 회귀분석을 실시하였다. 분석 결과, 주택에서 배출되는 음식물 쓰레기는 국 또는 찌개류, 나물반찬, 과일류 등 수분이 다량 함유되고 쉽게 부패되는 종류였고, 음식준비과정에서 많이 배출되고 있었으며, 쓰레기 배출시 악취와 벌레 등의 불쾌감과 쓰레기 배출시의 불편함이 지적되었다. 이로 인해 음식물 쓰레기의 에너지화와 부엌 싱크대에 음식물 쓰레기 무배출 시스템의 설치에 적극적이었으며, 그 시스템을 주택건설단계부터 구조적으로 설치되길 선호하였다. 회귀분석 결과, 주부 학력, 요리스타일과 식재료 구입계획의 식재료 구매단계 특성이 음식물 쓰레기의 자원화 경향에 통계적으로 유의한 요인들이었다. 즉, 주부 학력이 높을수록, 식재료 구매단계특성 중 식재료 구입계획이 허술할수록 음식물 쓰레기를 자원화하려는 경향이 높았다. 반면, 음식물 쓰레기 무배출 시스템 설치 희망에 미치는 요인은 통계적으로 유의하지 않았으나, 주부연령이 낮고 학력이 높을수록 가족생활주기가 자녀초등 청소년기일수록 음식물 쓰레기 무배출 시스템 설치를 적극적으로 희망하는 편이었다. 따라서, 쾌적한 주거환경 조성과 지속가능한 생활환경 창출을 위해 음식물 쓰레기의 자원화 및 무배출 시스템의 설치는 필요하며, 활발한 보급을 위해서는 사용자 친화적인 설계와 제도적 지원이 수반되어야 할 것이다.

이상혐기공정의 축산폐수 공공처리시설 적용 가능성에 관한 실험적 연구 (A Study on the Evaluation of Two-Phase Anaerobic Process for Public Livestock Wastewater Treatment Plant)

  • 오성모;김문호;배윤선;박철휘
    • 상하수도학회지
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    • 제21권3호
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    • pp.331-339
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    • 2007
  • The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a pilot scale two-phase anaerobic system operated up to a volumetric rate of $10m^3/day$. The pilot scale two-phase anaerobic process is consisted of a continuous-flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. The acidogenic CFSTR was operated at organic loading rates (OLR) between 1.8 and $14.4kgCOD/m^3{\cdot}day$, and the UASB reactor was operated between 0.5 and $5.6kgCOD/m^3{\cdot}day$. A stable maximum biogas production rate was $81m^3/day$ and the methane conversion rate of the organic matter varied from 0.30 to $0.42L\;CH_4/g\;COD_{removed}$(0.40) at hydraulic retention time (HRT) above 3.5days. The methane contents ranged from 73 to 82% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

양허증(陽虛證)의 임상적 질환 범위에 대한 고찰 (Study on Clinical Diseases of Yang Deficiency Pattern)

  • 박미선;김영목
    • 동의생리병리학회지
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    • 제27권2호
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    • pp.153-166
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    • 2013
  • Yang deficiency pattern is a representative syndrome differentiation. This article is a study on to which categories of modern diseases yang deficiency is assigned by reference to modern clinical papers and the meaning of yang deficiency interpreted with a perspective of Korean Medicine and a modern perspective. Yang deficiency, yang qi deficiency, lack of yang qi and yang qi debilitation are the words found in "Nei Ching" and yang qi can be interpreted as something to warm, drive and arouse. Zhangzhongjing considered recovery or loss of Yang as the key to life in "Shanghanlun". Danxi proposed "Yang being liable to hyperactivity, Yin being insufficient" and emphasized pathological ministerial fire of Yang exuberance rather than physiological ministerial fire of Yang deficiency. Zhangjingyue proposed "Yang not being in excess, Yin being often deficient" and understood growth and decline of yin qi are all led by yang qi and put emphasis on true yin in addition to yang qi. Diseases of yang deficiency pattern are related with decline of metabolic level, hypofunction of internal secretion, disorder of immune function, disorder of automatic nerve system, sympathetic nerve inhibition, metabolic disorder of microelements, increase of cGMP, change of microcirculation, low speed of blood stream, kidney malfunction. Diseases related with kidney are sterility, polycystic ovary syndrome, spinal stenosis, edema, renal failure, IgA nephropathy, erectile dysfunction, nephritis, prostatitis, benign prostatic hyperplasia, decrease of adrenal cortical hormone by nephrotic syndrome, myelodysplastic syndrome. Disease related with heart are heart failure, arrhythmia, cardiomyopathy, atherosclerosis heart disease, hypertension, hyperlipidemia, pulmonary heart disease. Diseases related with spleen are irritable bowel syndrome, ulcerative colitis. Diseases related with liver are hypothyroidism, liver cirrhosis ascites, hepatitis B, chronic hepatitis, hepatic diabetes. Diseases related with lung are allergic rhinitis, cough variant asthma, bronchial asthma, pulmonary emphysema. And diabetes mellitus, metabolic syndrome, aplastic anemia, headache, encephalatrophy, Alzheimer's disease are also related with yang deficiency.

교반막대추출법(SBSE)과 GC/MS를 이용한 수중의 Geosmin과 2-MIB의 분석 (Analysis of Geosmin and 2-MIB in Water by Stir Bar Sorptive Extraction (SBSE) and GC/MS)

  • 이화자;강임석
    • 대한환경공학회지
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    • 제31권1호
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    • pp.64-69
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    • 2009
  • 수돗물에서 geosmin과 2-MIB에 의한 곰팡이와 흙냄새는 소비자들에 대한 수돗물불신의 주된 요인이다. 따라서 geosmin과 2-MIB의 조기 검출 및 분석방법은 이취미 문제를 예방하는데 있어서 중요한 부분이다. 본 연구에서는 교반막대 추출법 (SBSE)과 GC/MS를 이용하여 geosmin과 2-MIB의 분석방법에 대하여 살펴보았다. 용매를 사용하지 않고 시료를 추출하는 SBSE 방법을 최적화하여 수중의 geosmin과 2-MIB를 분석하는데 적용하였다. 실험 결과 SBSE 방법은 간단하고 신속한 분석이 가능하여 소량(10~20 mL)의 시료를 사용하여 한 번에 많은 시료를 동시에 분석할 수 있었다. 그리고 SBSE 방법은 높은 회수율과 재현성을 보였다. 검출한계는 1~2 ng/L 이었으며 정량한계는 3~6 ng/L 이었다. 무엇보다도 SBSE는 수중의 geosmin과 2-MIB를 분석하는 데에 매우 신뢰성이 있고 실용적인 방법이라고 판단된다.

Implementation of Zero-Ripple Line Current Induction Cooker using Class-D Current-Source Resonant Inverter with Parallel-Load Network Parameters under Large-Signal Excitation

  • Ekkaravarodome, Chainarin;Thounthong, Phatiphat;Jirasereeamornkul, Kamon
    • Journal of Electrical Engineering and Technology
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    • 제13권3호
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    • pp.1251-1264
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    • 2018
  • The systematic and effective design method of a Class-D current-source resonant inverter for use in an induction cooker with zero-ripple line current is presented. The design procedure is based on the principle of the Class-D current-source resonant inverter with a simplified load network model that is a parallel equivalent circuit. An induction load characterization is obtained from a large-signal excitation test-bench based on parallel load network, which is the key to an accurate design for the induction cooker system. Accordingly, the proposed scheme provides a systematic, precise, and feasible solution than the existing design method based on series-parallel load network under low-signal excitation. Moreover, a zero-ripple condition of utility-line input current is naturally preserved without any extra circuit or control. Meanwhile, a differential-mode input electromagnetic interference (EMI) filter can be eliminated, high power quality in utility-line can be obtained, and a standard-recovery diode of bridge-rectifier can be employed. The step-by-step design procedure explained with design example. The devices stress and power loss analysis of induction cooker with a parallel load network under large-signal excitation are described. A 2,500-W laboratory prototype was developed for $220-V_{rms}/50-Hz$ utility-line to verify the theoretical analysis. An efficiency of the prototype is 96% at full load.

설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제27권7호
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

이미지 분석시스템을 이용한 부선컬럼에서 기포크기의 측정 (Measurement of Bubble Size in Flotation Column using Image Analysis System)

  • 안기선;전호석;박철현
    • 자원리싸이클링
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    • 제29권6호
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    • pp.104-113
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    • 2020
  • 기포크기는 컬럼부선에서 기포체류시간, 기포표면적플럭스(Sb) 및 운송율(Cr)에 영향을 미치는 중요 변수로 인식되고 있다. 본 논문은 부선컬럼에서 기포크기의 측정방법, 가동변수들의 관계 그리고 가스분산특성을 논한다. 기포크기는 고속카메라와 이미지 분석 시스템을 이용하여 가동변수들(가스속도, 세척수속도, 기포제농도)의 조건에 따라 부선컬럼에서 직접적으로 측정되었다. 각 측정과 산정된 기포크기 값들을 비교한 관계식이 ±15~20의 오차범위 내에서 도출되었고 평균 기포크기(Sauter mean diameter)는 0.718mm로 확인되었다. 본 시스템으로부터 기포크기 및 분포를 조절할 수 있는 경험식이 가동조건들(Jg: 0.65~1.3cm/s, JW: 0.13~0.52cm/s, frother concentration: 60~200ppm) 하에서 개발되었다. 기포제농도의 증가는 표면장면과 기포크기를 감소시킨다. 임계병합농도는 표면장력이 가장 낮은 49.24mN/m일 때인 기포제농도 200ppm이라고 판단된다. 공기속도의 감소, 기포제농도 및 세척수속도의 증가에 따라 기포크기가 감소하는 경향을 보였다. 가스홀드업은 가스속도와 비례관계에 있으며 고정된 가스속도 조건에서 기포제농도 및 세척수속도와 비례관계였다.

덕트 팬-베인 형상의 제자리 비행 공력 특성 및 조종 성능 개선에 관한 수치적 연구 (Numerical Investigation of Aerodynamic Characteristics of a Ducted Fan-Vane Configuration and Improvement of Control Performance in Hover)

  • 강동훈;임진우;유흥철
    • 한국항공우주학회지
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    • 제49권3호
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    • pp.221-231
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    • 2021
  • 본 연구에서는 덕트 팬-상/하부 베인의 제자리 비행 공력 특성에 관한 수치적 연구를 수행하였다. 일정한 회전 속도, 블레이드 콜렉티브 피치각에서 상부 베인 꺾임각 변화에 따른 시스템 구성 요소별 공력 민감도를 분석하였다. 개별 베인 작동 메커니즘과 덕트-베인 공력 상호 간섭의 물리적 특성을 파악하고자 베인의 조종 성능과 덕트 공력하중 분포를 상세히 분석하였다. 마지막으로, 전기체의 조종 성능 개선을 위해 상부 베인의 새로운 작동 메커니즘을 제안하였다. 상부 베인 꺾임각 변화에 따라 상부 베인 측력과 롤링 모멘트는 선형 증가하였으나, 전기체 측력은 덕트에서 작용하는 반력에 의해 현저히 낮게 나타났다. 또한 덕트 수축부 가까이 위치한 상부 베인이 조종 성능 변화에 가장 큰 역할을 하였다. 덕트와 상부 베인 흡입면의 공력 상호 간섭에 의해 덕트의 음압이, 덕트와 상부 베인의 압력면 공력 상호 간섭에 의해 압력 회복이 발생하여 덕트의 비대칭 공력 증가의 원인이 되었다. 4개의 상부 베인을 0°로 고정시키거나 제거했을 때, 덕트의 비대칭 공력은 감소하고, 전기체의 롤링 모멘트는 80%까지 증가하여 공력 성능이 개선되었다.

설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.