• 제목/요약/키워드: Energy loss reduction

검색결과 340건 처리시간 0.027초

고혈압, 고지혈증, 퇴행성 관절염을 동반한 비만 환자의 증례보고 (A Case Report for a Obese Patient Accompanied with Hypertension, Dyslipidemia and Osteoarthritis)

  • 김동열;김길수
    • 한방비만학회지
    • /
    • 제1권1호
    • /
    • pp.13-20
    • /
    • 2001
  • 비만이란 음식물로 섭취한 칼로리가 신체활동으로 소모된 칼로리보다 많은 경우 잉여 칼로리가 체지방으로 축적된 경우로서 심장병, 고혈압, 동백경화증, 고지혈증, 뇌졸중, 당뇨병, 지방간 등의 유병율을 높여 현대인의 건강을 위협하는 중요한 원인이 된다고 알려지고 있다. 최근 저자는 비만과 고지혈증, 슬관절의 퇴행성 관절염으로 체중증가, 슬관절통, 하지방산통을 주소로 하는 환자 1례를 초저열량식이요법, 한약요법, 운동요법과 한방물리요법을 시행한 결과 체중감소와 체성분의 변화, 혈액학적 변화, 자각증상의 개선의 효과를 보았기에 치료내용과 경과를 보고하는 바이다.

  • PDF

Research Activity on Rocket-Ramjet Combined-cycle Engine in JAXA

  • Takegoshi, Masao;Kanda, Takeshi
    • 한국추진공학회:학술대회논문집
    • /
    • 한국추진공학회 2008년 영문 학술대회
    • /
    • pp.460-468
    • /
    • 2008
  • Recent activities on the scramjet and rocket-ramjet combined-cycle engine of Japan Aerospace Exploration Agency(JAXA) are herein presented. The scramjet engines and combined-cycle engines have been studied in the world and JAXA has also studied such the engines experimentally, numerically and conceptually. Based on the studies, 2 to 3 m long, hydrogen-fueled engine models were designed and tested at the Ramjet Engine Test Facility(RJTF) and the High Enthalpy Shock Tunnel(HIEST). A scramjet engine model was tested in Mach 10 to 14 flight condition at HIEST. A 3 m long scramjet engine model was designed to reduce a dissociation energy loss in a high temperature condition. Drag reduction by a tangential injection and two ways of a transverse fuel injection were examined. Combustor model tests at three operating modes of the combined-cycle engine were conducted, demonstrating the combustor operation and producing data for the engine design at each mode. Aerodynamic engine model tests were conducted in a transonic wind tunnel, demonstrating the engine operation in the ejector-jet mode. A 3 m long combined-cycle engine model has been tested in the ejector-jet mode and the ramjet mode since March 2007. Carbon composite material was examined for application to the engines. Production of the cooling channel on a nickel alloy plate succeeded by the electro-chemical etching.

  • PDF

Evaluation of seasonal effects on production performance of lactation sows reared in two different environments in South Korea

  • Yin, Jia;Yan, Lei;Kim, Inho
    • 농업과학연구
    • /
    • 제46권3호
    • /
    • pp.417-426
    • /
    • 2019
  • This study was conducted to evaluate seasonal effects on production performance of lactation sows reared in two different environments in South Korea. A total of 76 sows ($Landrace{\times}Yorkshire$) from the Dankook University experimental farm and 120 sows ($Landrace{\times}Yorkshire$) from a commercial farm were collected. In the current study, reduced (p < 0.01) feed intake and energy intake during lactation were observed in warm season compared with cool season in both farms. Sows in cool season had higher backfat thickness at weaning but lower back fat loss (p < 0.01) than those in warm season. The weaning to estrus interval was lower (p < 0.01) in cool season than in warm season. Piglets weaned in warm season had lower (p < 0.01) body weight (BW), body weight gain (BWG), and average daily gain (ADG) at weaning than did those weaned in cool season on the Dankook University farm, whereas the reduction effect was only observed during 0 - 21 d on the commercial farm (p < 0.01). Moreover, piglets weaned in cool season had higher BW, BWG, and ADG (p < 0.05) on both farms. In conclusion, our results indicate that warm season had very negative effects on feed intake and production performance of lactating sows and piglets.

Removal of iron oxide scale from boiler feed-water in thermal power plant by high gradient magnetic separation: field experiment

  • Akiyama, Yoko;Li, Suqin;Akiyama, Koshiro;Mori, Tatsuya;Okada, Hidehiko;Hirota, Noriyuki;Yamaji, Tsuyoshi;Matsuura, Hideki;Namba, Seitoku;Sekine, Tomokazu;Mishima, Fumihito;Nishijima, Shigehiro
    • 한국초전도ㆍ저온공학회논문지
    • /
    • 제23권3호
    • /
    • pp.14-19
    • /
    • 2021
  • The reduction of carbon dioxide emissions becomes a global issue, the main source of carbon dioxide emissions in the Asian region is the energy conversion sector, especially coal-fired power plants. We are working to develop technologies that will at least limit the increase in carbon dioxide emissions from the thermal power plants as one way to reduce carbon dioxide emissions. Our research aims to reduce carbon dioxide emissions by removing iron oxide scale from the feedwater system of thermal power plants using a superconducting high-gradient magnetic separation (HGMS) system, thereby reducing the loss of power generation efficiency. In this paper, the background of thermal power plants in Asia is outlined, followed by a case study of the introduction of a chemical cleaning line at an actual thermal power plant in Japan, and the possibility of introducing it into the thermal power plants in China based on the results.

전기자동차 급속충전기용 넓은 전압 범위를 갖는 30kW급 SiC MOSFET 기반 고속 스위칭 LLC 컨버터 설계 및 병렬 운전 (Design and Parallel Operation of 30 kW SiC MOSFET-Based High Frequency Switching LLC Converter With a Wide Voltage Range for EV Fast Charger)

  • 이기영;민성수;박수성;조영찬;이상택;김래영
    • 전력전자학회논문지
    • /
    • 제27권2호
    • /
    • pp.165-173
    • /
    • 2022
  • The electrification trend of mobility increases every year due to the development of power semiconductor and battery technology. Accordingly, the development and distribution of fast chargers for electric vehicles (EVs) are in demand. In this study, we propose a design and implementation method of an LLC converter for fast chargers. Two 15 kW LLC converters are configured in parallel to have 30 kW rated output power, and the control algorithm and driving sequence are designed accordingly and verified. In addition, the improved power conversion efficiency is confirmed through zero-voltage switching (ZVS) of the LLC converter and reduction of turn-off loss through snubber capacitors. The implemented 30 kW LLC converters show a wide output voltage range of 200-950 V. Experiments applying various load conditions verify the converter performance.

Seismic equivalent linear response of a structure by considering soil-structure interaction: Analytical and numerical analysis

  • Maroua Lagaguine;Badreddine Sbartai
    • Structural Engineering and Mechanics
    • /
    • 제87권2호
    • /
    • pp.173-189
    • /
    • 2023
  • For a given structural geometry, the stiffness and damping parameters of the soil and the dynamic response of the structure may change in the face of an equivalent linear soil behavior caused by a strong earthquake. Therefore, the influence of equivalent linear soil behavior on the impedance functions form and the seismic response of the soil-structure system has been investigated. Through the substructure method, the seismic response of the selected structure was obtained by an analytical formulation based on the dynamic equilibrium of the soil-structure system modeled by an analog model with three degrees of freedom. Also, the dynamic response of the soil-structure system for a nonlinear soil behavior and for the two types of impedance function forms was also analyzed by 2D finite element modeling using ABAQUS software. The numerical results were compared with those of the analytical solution. After the investigation, the effect of soil nonlinearity clearly showed the critical role of soil stiffness loss under strong shaking, which is more complex than the linear elastic soil behavior, where the energy dissipation depends on the seismic motion amplitude and its frequency, the impedance function types, the shear modulus reduction and the damping increase. Excellent agreement between finite element analysis and analytical results has been obtained due to the reasonable representation of the model.

EFFECT OF Al/Cu WEIGHT FRACTION ON THE MECHANICAL AND ELECTRICAL PROPERTIES OF Al-Cu CONDUCTORS FOR OVERHEAD TRANSMISSION LINES

  • DEOKHYUN HAN;GEON-HONG KIM;JAESUNG KIM;BYUNGMIN AHN
    • Archives of Metallurgy and Materials
    • /
    • 제65권3호
    • /
    • pp.1019-1022
    • /
    • 2020
  • In the past few years, overhead copper transmission lines have been replaced by lightweight aluminum transmission lines to minimize the cost and prevent the sagging of heavier copper transmission lines. High strength aluminum alloys are used as the core of the overhead transmission lines because of the low strength of the conductor line. However, alloying copper with aluminum causes a reduction in electrical conductivity due to the solid solution of each component. Therefore, in this study, the authors attempt to study the effect of various Al/Cu ratios (9:1, 7:3, 5:5) to obtain a high strength Al-Cu alloy without a significant loss in its conductivity through powder metallurgy. Low-temperature extrusion of Al/Cu powder was done at 350℃ to minimize the alloying reactions. The as-extruded microstructure was analyzed and various phases (Cu9Al4, CuAl2) were determined. The tensile strength and electrical conductivity of different mixing ratios of Al and Cu powders were studied. The results suggest that the tensile strength of samples is improved considerably while the conductivity falls slightly but lies within the limits of applications.

The Extraction of Co-PET from Non-Woven Fabrics of Nylon/Co-PET Sea-island Type Composite Microfiber

  • Park, Myung-Soo;Yoon, Jong-Ho;Cho, Dae-Hyun
    • 한국의류산업학회지
    • /
    • 제3권5호
    • /
    • pp.466-472
    • /
    • 2001
  • To find a suitable condition in this process examined, we investigated the main control factors, such as, the NaOH concentrations, such as, the NaOH concentrations, the heat treating times, and the heating temperatures. The resulting mechanical properties of the fabrics also studied. The samples used were Nylon/Co-PET sea-island type composite microfiber (Co-PET content: 35%) non-woven fabric. The conclusions obtained were as follows. 1. For the complete extraction of Co-PET from the sample non-woven fabric in the dry hot air process, $160^{\circ}C$ of air temperature, 15 min. of treatment time, and around 30% of NaOH concentration were required. On the other hand, in the wet hot air process, $140^{\circ}C$ of air temperature, 3.5 min. of treatment time, and around 30% of NaOH concentration were required. 2. The mechanical properties of the continuous processed samples showed that the WT, B, and WC increased with increasing the weight reduction ratio. However, the G, decreased with increasing the weight loss ratio. Note that, particularly in B, it increased drastically when the weight deduction ratios exceeded 30%. 3. As increasing the wet hot air temperature from 130 to $140^{\circ}C$, B appeared to increase, however, WT, G, and WC appeared to decrease. 4. The best condition found in this continuous process to extract Co-PET is the wet hot air temperature of 140, NaOH concentration of 28% or above, and the treatment time 2-4 min.

  • PDF

전력설비에서의 SF6 회수 및 재활용 CDM 방법론 개발 (Development on the Methodology of CDM Projects in the SF6 Recovery and Recycling of Electrical Equipment)

  • 표정관;사재환;전의찬
    • 한국기후변화학회지
    • /
    • 제2권3호
    • /
    • pp.143-159
    • /
    • 2011
  • 전력설비의 $SF_6$ 가스 배출저감을 통한 CDM 방법론 AM0035(Approved Methodology 0035. Ver 1.0)를 적용한 사업은 EB(Executive Board) 41차 회의 결과에 따라 $SF_6$ 가스의 운영 상태 및 과정, 불확도를 포함한 베이스 라인, 프로젝트 배출량 산정에 주요 매개변수의 직접 모니터링을 명확하게 입증해야 한다. 본 연구를 통하여 유지보수 시 회수율, 폐기 교체 전 후 가스 순도, 재처리(reclamation) 전 후 $SF_6$ 가스 손실률, 회수 설비 및 재처리 설비의 전력사용량에 의한 배출량, 운반 시 발생되는 누출량(leakage)의 다양한 모니터링 결과를 보수적으로 고려하였다. 그 결과, 기존 방법론보다 베이스 라인 배출량이 감소하고, 프로젝트 배출량이 증가되어 저감량이 감소하는 것을 확인하였다.

Modelling Pasture-based Automatic Milking System Herds: The Impact of Large Herd on Milk Yield and Economics

  • Islam, M.R.;Clark, C.E.F.;Garcia, S.C.;Kerrisk, K.L.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • 제28권7호
    • /
    • pp.1044-1052
    • /
    • 2015
  • The aim of this modelling study was to investigate the effect of large herd size (and land areas) on walking distances and milking interval (MI), and their impact on milk yield and economic penalties when 50% of the total diets were provided from home grown feed either as pasture or grazeable complementary forage rotation (CFR) in an automatic milking system (AMS). Twelve scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as 'moderate'; optimum pasture utilisation of 19.7 t DM/ha, termed as 'high') and 2 rates of incorporation of grazeable complementary forage system (CFS: 0, 30%; CFS = 65% farm is CFR and 35% of farm is pasture) were investigated. Walking distances, energy loss due to walking, MI, reduction in milk yield and income loss were calculated for each treatment based on information available in the literature. With moderate pasture utilisation and 0% CFR, increasing the herd size from 400 to 800 cows resulted in an increase in total walking distances between the parlour and the paddock from 3.5 to 6.3 km. Consequently, MI increased from 15.2 to 16.4 h with increased herd size from 400 to 800 cows. High pasture utilisation (allowing for an increased stocking density) reduced the total walking distances up to 1 km, thus reduced the MI by up to 0.5 h compared to the moderate pasture, 800 cow herd combination. The high pasture utilisation combined with 30% of the farm in CFR in the farm reduced the total walking distances by up to 1.7 km and MI by up to 0.8 h compared to the moderate pasture and 800 cow herd combination. For moderate pasture utilisation, increasing the herd size from 400 to 800 cows resulted in more dramatic milk yield penalty as yield increasing from c.f. 2.6 and 5.1 kg/cow/d respectively, which incurred a loss of up to $AU 1.9/cow/d. Milk yield losses of 0.61 kg and 0.25 kg for every km increase in total walking distance (voluntary return trip from parlour to paddock) and every one hour increase in MI, respectively. The high pasture utilisation combined with 30% of the farm in CFR in the farm increased milk yield by up to 1.5 kg/cow/d, thereby reducing loss by up to $0.5/cow/d (c.f. the moderate pasture and 800 cow herd scenario). Thus, it was concluded that the successful integration of grazeable CFS with pasture has the potential to improve financial performance compared to the pasture only, large herd, AMS.