• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.201-201
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• 2010

The evaporative desalination system with solar energy would be the efficient and attractive method to get fresh water. This study was described the development of Multi Effect Distillation(MED) with solar energy desalination system. The system was designed and manufactured Multi effect distillation on the capacity of $3m^3$/day. The experimental apparatus consists mainly of ejector pump, Hot water pump, flow meter, demister, cooler, evaporator and condenser. Evaporator and condenser were made Shell&Tube Heat Exchanger type with corrugated tube. The experimental variables were chosen $75^{\circ}C$ for hot water inlet temperature, 40, 60 and $80{\ell}$/min for hot water inlet volume flow rate, 6.0 and $8.0{\ell}$/min for evaporator feed seawater flow rate, $18^{\circ}C$ for sea water inlet temperature to cover the average sea water temperature and the salinity of sea water is measured about 33,000 PPM (parts per million). for a year in Korea. This study was analyzed the results of thermal performance of Multi Effect Distillation. The results are as follows, The experimental Multi effect distillation is required about 40 kW heat source for production of $3m^3$/day fresh water. Various operating flow rate was confirm in the experiments to get the optimum design data and the results showed that the optimum total flow was $8.0{\ell}$/min. Comparison of Single Effect Distillation with Multi Effect Distillation showed MED is at least more than double of SED.

• International Journal of Industrial Entomology and Biomaterials
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• 제14권1호
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• pp.15-21
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• 2007

Three newly authorized bivoltine silkworm hybrids namely, $CSR2{\times}CSR4$ (productive single hybrid), $(CSR6{\times}CSR26){\times}(CSR2{\times}CSR27)$ (productive double hybrid) and $CSR18{\times}CSR19$ (robust single hybrid) were chosen for the present study. These hybrids were subjected to different temperature and humidity treatments i.e., $25{\pm}$1^{\circ}C and RH $65{\pm}5%$ (control), $30{\pm}1^{\circ}C$, with combinations of low relative humidity (RH $65{\pm}5%$) and high RH ($85{\pm}5%$) at different stages during rearing and spinning of silkworm larvae. The larvae of after 3rd moult were subjected to different thermal and humidity stress till the assessment of cocoon traits. The comparative rearing and reeling performance clearly indicated that the deleterious effect of high temperature and high RH was more pronounced for the majority of traits such as cocoon uniformity, cocoon weight, shell weight, shell percentage, reelability, filament length, raw silk percentage raw silk recovery denier and waste percentage on silk weight than other temperature and RH treatments and this effect was almost similar for all three silkworm hybrids studied. The present investigation clearly indicate that the deleterious effect of high temperature and high RH was more pronounced on rearing and spinning of silkworm larvae than other temperature and RH treatments and similar effect was noticed for all the three silkworm hybrids studied. The cocoon characters can be improved by providing ideal environmental conditions even during spinning stage of larvae affected with high temperature and RH. The study also suggest that high temperature and low humidity has greater effect during rearing stage than spinning stage.

• Structural Engineering and Mechanics
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• 제56권4호
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• pp.667-694
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• 2015

The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.

• Wind and Structures
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• 제23권4호
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• pp.275-300
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• 2016

Synchronous multi-pressure measurements were carried out with relatively long time duration for a double-layer reticulated shell roof model in the atmospheric boundary layer wind tunnel. Since the long roof is open at two ends for the storage of coal piles, three different testing cases were considered as the empty roof without coal piles (Case A), half coal piles inside (Case B) and full coal piles inside (Case C). Based on the wind tunnel test results, non-Gaussian time-dependent statistics of net wind pressure on the shell roof were quantified in terms of skewness and kurtosis. It was found that the direct statistical estimation of high-order moments and peak factors is quite sensitive to the duration of wind pressure time-history data. The maximum value of COVs (Coefficients of variations) of high-order moments is up to 1.05 for several measured pressure processes. The Mixture distribution models are proposed for better modeling the distribution of a parent pressure process. With the aid of mixture parent distribution models, the existing translated-peak-process (TPP) method has been revised and improved in the estimation of non-Gaussian peak factors. Finally, non-Gaussian peak factors of wind pressure, particularly for those observed hardening pressure process, were calculated by employing various state-of-the-art methods and compared to the direct statistical analysis of the measured long-duration wind pressure data. The estimated non-Gaussian peak factors for a hardening pressure process at the leading edge of the roof were varying from 3.6229, 3.3693 to 3.3416 corresponding to three different cases of A, B and C.

• 한국패류학회지
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• 제31권2호
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• pp.73-81
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• 2015

본 연구는 전복 육상 중간양성 시 생산성과 경제성 향상을 유도하고자 육상 중간양성 방식별로 수용한 전복치패에 배합사료와 해조류를 공급하여 성장 및 생존율을 조사하였다. 실험 전복은 2012년에 종묘생산 된 양성 1년생 (각장 22.74-23.67 mm) 을 사용하여 해조류 (sea weed diet, SW) 와 배합사료 (artificial, A) 공급구에 각각 바닥식 (floor culture, FC), 그물 바닥식 (net floor culture, NFC), 이중 은신처 (double shelter culture, DSC) 그리고 육상 가두리 (indoor net cage culture, INCC) 로 총 8개의 중간양성 방식을 2반복으로 설정하여 10개월간 사육하였다. 월별 각장 절대성장률 (absolute growth rate of shell length, $AGR_{SL}$), 일간성장률 (daily growth rate of shell length), 중량 변화에서 9월부터 11월 까지를 제외하고 유의적 차이가 없었다. 육상수조 내 사육방법별 월별 중량변화는 유의적 차이가 없었다. 성장에서는 각장, 각폭, 체중에 대한 모든 성장지표에서 유의적 차이는 보이질 않았으나, 배합사료 공급구의 이중쉘터 방식이 높은 값을 보였다. 생존율은 A-FC가 70% 이상으로 55-60%인 다른 실험구보다 유의적으로 높았으며 (P < 0.05), 생사료와 배합사료 공급한 전복치패 가식부의 일반성분은 차이가 없었다. 따라서 2 cm 이상의 전복치패를 육상수조에서 서로 다른 중간 양성 방식별로 사육 시 배합사료와 생사료 공급은 성장차이를 보이지 않으며, 배합사료를 공급한 바닥식 중간양성이 생존율이 높게 나타나, 육상 중간양성 시 바닥식 양성이 생산성 향상에 유리할 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.943-945
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• 2002

This paper presents conceptual design and 3-D electromagnetic analysis of 1MVA transformer with BSCCO-2223 High Tc Superconducting (HTS) tapes. The rated voltages of each sides of the transformer are 22.9 kV and 6.6 kV, and double pancake windings were adopted. High voltage and Low voltage sides were composed of several double pancake windings. Four HTS tapes were wound in parallel for the windings of low voltage side and were transposed in order to distribute the currents equally in each conductor. The transformer core was designed as a shell type core made of laminated silicon steel plates and the core is separated with the windings by a cryostat with Fiberglass Reinforced Plastics(FRP). A sub-cooling system using $LN_2$ were designed to maintain the coolant temperature of 65K. Finally perpendicular components of magnetic field applied to tapes were calculated 0.24T in the rated operation using 3-D analysis. A real 1MVA HTS transformer will be manufactured in near future based on the design parameters presented in this paper.

• Progress in Superconductivity
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• 제4권1호
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• pp.86-89
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• 2002

In this paper, the design of a IMVA single-phase high temperature superconducting(HTS) power transformer with BSCCO-2223 HTS tapes is presented. The rated voltages of each sides of the transformer are 22.9 ㎸ and 6.6 ㎸, respectively The winding of 1MVA HTS transformer is consisted of double pancake type HTS windings, which have advantages of insulation and distribution of high voltage, and are cooled by subcooled liquid nitrogen of 65K. Four HTS tapes were wound in parallel for the windings of low voltage side and the four parallel conductors are transposed. The design of 1MVA HTS transformer, a shell type core made of laminated silicon steel plate is chosen, and the core is separated with the windings by a cryostat with a room temperature bore. The cryostat made of non-magnetic and non-conducting material and a liquid nitrogen sub-cooling system is designed in order to maintain the coolant's temperature of 65K. For electromagnetic analysis of 1MVA HTS transformer, a finite element method of an axis of symmetry is used. The maximum perpendicular component of magnetic flux density of pancake windings is about 0.15T. And through analyzing the magnetic field distribution, an optimal winding arrangement of 1MVA HTS transformer is obtained.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.109-114
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• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• 설비공학논문집
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• 제20권12호
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• pp.781-788
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• 2008

A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, 'U' tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the subroutines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.

• Journal of Pharmaceutical Investigation
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• 제38권2호
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• pp.99-104
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• 2008

PLGA micro/nano particles encapsulating ranitidine as a hydrophilic model drug were prepared by the double-emulsion solvent evaporation method. Surface morphology investigation by scanning electron microscope (SEM) showed that the emulsification by sonication could produce nanoparticles, whereas microparticles were prepared using high speed homogenizer. Moreover, while nanohalf-shell structure instead of spherical nanoparticle could be produced by adding poloxamer into oil phase (MC) with PLGA 504H, the addition of poloxamer didn't change particle shape in case of PLGA 502H. On the other hand, microparticle with poloxamer had more surface pores than those without poloxamer. The size and polydispersity (PDI) of particles were determined by particle size analyzer. Effective diameters of particles were in the range of $400{\sim}800\;nm$ and $1200{\sim}3300\;nm$ in case of nanoparticles and microparticles, respectively. Encapsulation efficiencies were in the range of $1.2{\sim}2.9%$. The addition of poloxamer produced the particles with higher encapsulation efficiency. In vitro release study in phosphate buffer (pH 7.4) at $37^{\circ}C$ showed common large initial burst release. However, the relative slower release profile could be observed in case of microparticles. Poloxamer addition increased the release rate, which was thought to be related to the increased surface area of particles.