• Title/Summary/Keyword: Absorption performance

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A field Study to Evaluate Cooling Effects of Green Facade under Different Irrigation Conditions - Focusing on modular green facade planted with Hedera helix L and Pachysandra terminalis - (관수조절에 의한 벽면녹화의 냉각효과 분석 연구- 아이비, 수호초를 식재한 모듈형 벽면녹화를 중심으로-)

  • Kim, Eun-Sub;Yun, Seok-Hwan;Piao, Zheng-gang;Jeon, Yoon-Ho;Kang, Hye-Won;Kim, Sang-Hyuck;Kim, Ji-Yeon;Lee, Young-Gu;Lee, Dong-Kun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.24 no.6
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    • pp.121-132
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    • 2021
  • Green facade has a significant impact on building's energy performance by controlling the absorption of solar radiation and improving outdoor thermal comfort through shading and evapotranspiration. In particular, since high-density building does not enough green space, green facade, and rooftop greening using artificial ground plants are highly utilized. However, the level of cooling effect according to plant traits and irrigation control is different. Therefore, in this study, the cooling effect analyzed for a total of 4 cases by controlling the irrigation condition based on hedera and spurge. Although hedera under sufficient water had the highest cooling effect(-2℃~-4℃), had the lowest cooling effect under non-irrigation(+1.1℃~+4.4℃). In addition, hedera under sufficient water had cooling effect than hedera under non-irrigation(-1℃~-8.1℃) and in the case of spurge, it had cooling effect(-0.3℃~-7.8℃) more than non-irrigation. As a result of measuring the amount of transpiration according to the light intensity (PAR) and carbon dioxide concentration conditions, transpiration of hedera was higher than the spurge (respectively 0.63204mmolm-2s-1, 0.674367mmolm-2s-1). The difference in the cooling effect of the green facade under irrigation condition was significant. But the potential cooling effect of green facade according to plants species was different. Therefore, in order to maximize and continuously provide the cooling effect of green facade in urban areas, it is necessary to consider the characteristics of plants and the control of water supply through the irrigation system.

Calcium chloride is a better calcium source rather than calcium carbonate for weanling pigs

  • JunYoung, Mun;ChangBeon, Lee;Abdolreza, Hosseindoust;SangHun, Ha;Habeeb, Tajudeen;JinSoo, Kim
    • Journal of Animal Science and Technology
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    • v.64 no.5
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    • pp.871-884
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    • 2022
  • Two experiments were conducted to evaluate the effects of calcium (Ca) levels in weanling pigs (Landrace × Yorkshire × Duroc). In experiment 1, one hundred and eighty weanling pigs were randomly allotted to one of the three treatments. The treatments were low (Ca 0.60% in phase 1 and 0.50% in phase 2), standard (Ca 0.72% in phase 1 and 0.66% in phase 2), and high (Ca 0.84% in phase 1 and 0.72% in phase 2). In experiment 2, hundred and forty weanling pigs were randomly assigned to one of four treatments differing in Ca levels (high and low) and sources (CaCl2 and CaCO3) in a 2 × 2 factorial arrangement. There were 10 pigs per replicate in both experiments, with 6 replicates in each treatment, and they were conducted in two phases (phase 1, days 0-14; phase 2, days 15-28). In experiment 1, body weight (BW), average daily gain (ADG), and growth to feed ratio (G/F) increased as the Ca level decreased (p < 0.05). P digestibility was higher in the low-Ca diet group than in the high-Ca diet group (p <0.05). In experiment 2, the final BW, ADG, and G/F increased in the CaCl2 diet group compared with the case in the CaCO3 diet group (p < 0.05). The digestibility of crude protein (CP), Ca, and P was higher in the CaCl2 diet group than in the CaCO3 diet group (p < 0.05). Cl- levels were higher in the CaCl2 diet group than in the CaCO3 diet group (p < 0.05). The bicarbonate (HCO3-), base excess (BE), and electrolyte balance (EB) levels were lower in the CaCl2 diet group than in the CaCO3 diet group (p < 0.05). Hematocrit increased as the Ca level decreased (p < 0.05). The HCO3- interacted with the Ca sources and thus, affected the Ca levels (p < 0.05). Bone ash, Ca, and P were downregulated in the low-Ca diet group compared with the case in the high-Ca diet group. Overall, the low dietary Ca supplementation led to greater growth performance. Furthermore, CaCl2 appeared to be a better Ca source than CaCO3 because of the greater digestibility of CP, Ca, and P, and improved EB.

A study on the standard for determining airborne sound insulation performance of sound barrier panels (방음판의 음향투과손실 측정규격에 관한 연구)

  • Oh, Yang Ki
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.3
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    • pp.302-311
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    • 2022
  • Sound barrier walls are one of the most effective alternatives for reducing environmental noise on roads and railways in the city center. The insertion loss of the sound barrier against road traffic noise is the sum of the sound transmission loss, sound absorption loss, and sound energy reduction due to the diffraction attenuation of the sound barrier. The sound transmission loss of the sound barrier is one of the important factors that determine the insertion loss of the sound barrier and is a basic indicator that determines the performance of the sound barrier. Nevertheless, there is not a separate standard in Korea for measuring the acoustic transmission loss of sound barrier panels. There are only a few conditions in KS F 4770 series that stipulates on the general material of sound barrier panels. This thesis examines the necessity of the acoustic transmission loss measurement and evaluation standards of sound barrier walls, and seeks a measurement method in a free sound field (anechoic chamber) sound receiving room considering the characteristics of sound barrier walls installed in external spaces, unlike indoor building materials. In addition, a single number evaluation method using a reference spectrum was proposed so that the sound insulation effect according to various installation places such as roadside or railroad side can be easily displayed.

Enhancement of Buckling Characteristics for Composite Square Tube by Load Type Analysis (하중유형 분석을 통한 좌굴에 강한 복합재료 사각관 설계에 관한 연구)

  • Seokwoo Ham;Seungmin Ji;Seong S. Cheon
    • Composites Research
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    • v.36 no.1
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    • pp.53-58
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    • 2023
  • The PIC design method is assigning different stacking sequences for each shell element through the preliminary FE analysis. In previous study, machine learning was applied to the PIC design method in order to assign the region efficiently, and the training data is labeled by dividing each region into tension, compression, and shear through the preliminary FE analysis results value. However, since buckling is not considered, when buckling occurs, it can't be divided into appropriate loading type. In the present study, it was proposed PIC-NTL (PIC design using novel technique for analyzing load type) which is method for applying a novel technique for analyzing load type considering buckling to the conventional PIC design. The stress triaxiality for each ply were analyzed for buckling analysis, and the representative loading type was designated through the determined loading type within decision area divided into two regions of the same size in the thickness direction of the elements. The input value of the training data and label consisted in coordination of element and representative loading type of each decision area, respectively. A machine learning model was trained through the training data, and the hyperparameters that affect the performance of the machine learning model were tuned to optimal values through Bayesian algorithm. Among the tuned machine learning models, the SVM model showed the highest performance. Most effective stacking sequence were mapped into PIC tube based on trained SVM model. FE analysis results show the design method proposed in this study has superior external loading resistance and energy absorption compared to previous study.

Comparison of Milling and Flour Quality Characteristics of Foreign Wheat and Korean Wheat

  • Jinhee Park;Kyeong-Hoon Kim;Chon-Sik Kang;Go Eun Lee;Kyeong-Min Kim;Mina Kim;Han-yong Jeong;Yurim Kim;Jiyoung Shon;Jong-Min Ko
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.296-296
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    • 2022
  • This study was investigated to compare the milling and physicochemical characteristics of six Korean wheat cultivars (Keumkang, KK; Jokyung, JK; Goso, GS; Joongmo2008, JM; Baekkang, BK; Saekeumkang, SKK) and five foreign wheat classes (Australian standard white wheat, ASW; Australian hard, AH; US northern spring, NS; US hard red winter, HRW; Soft wheat, SW). Korea and foreign wheat grains were milled using a Buhler MLU-202. Flour moisture, ash, protein, gluten, sedimentation, particle size, solvent retention capacity (SRC) and dough properties of flour were analyzed. Results showed that the hard wheats had a greater total flour yield and reduction fraction yield than the soft wheats regardless of the country. However, there were in the milling characteristics between the US and Korean soft wheats. GS, a soft wheat in Korea, had the lowest flour yield (59.6%) and the highest bran fraction yield (21.4%). The particle sizes of flour by milling fraction were B1>B2>B3 for the largest, and the R1〈R2〈R3 for the smallest. Particle size, ash, protein contents and the values of lactic acid SRC showed highly correlated with flour yield. The gluten-performance-index (GPI) is the ratio of the lactic acid SRC value to the sum of sodium carbonate and sucrose SRC values, and it has been used as a quality indicator for overall performance potential of flour. GPI values differed depending on the wheat variety or class, JM (0.82) was the highest value, and SKK (0.56) and SW (0.59) were low. The curve pattern of the Mixolab result also gives a quality indication of the flour sample. JM and NS flour had similar pattern at water absorption and gluten strength parameters and BK and HRW had similar viscosity patterns. These results will enable further study for blending Korean wheat cultivar to improve the flour quality.

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Synthesis and Characteristic Evaluation of Downward Conversion Phosphor for Improving Solar Cell Performance (태양전지 성능향상을 위한 하향변환 형광체의 합성 및 특성평가)

  • Jae-Ho Kim;Ga-Ram Kim;Jin-To Choi;Soo-Jong Kim
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.5
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    • pp.523-528
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    • 2023
  • The applicability as a material to improve solar cell performance was reviewed by synthesizing a phosphor that emits red wavelengths by a liquid synthesis method using a metal salt aqueous solution and a polymer medium as a starting material. An aqueous solution was prepared using nitrate of metals such as Ca, Zn, Al, and Eu, and a precursor impregnated with starch, a natural polymer, was sintered to synthesize CaZnAlO:Eu phosphor powder. The surface structure and composition analysis of the synthesized CaZnAlO:Eu phosphor powder were analyzed by scanning electron microscope(SEM) and energy-dispersed X-ray spectroscopy(EDS). The crystal structure of CaZnAlO:Eu phosphor particles was analyzed by an X-ray diffraction analyzer (XRD). As a result of measuring the photoluminescence(PL) characteristics of the phosphor, it was confirmed that a red phosphor with a light emitting wavelength of 650-780nm was successfully synthesized. According to SEM and EDS analysis, the synthesized Ca14Zn6Al9.93O35:Eu3+0.07 phosphor powder has a uniform particle size, and Eu ions used as an activator are present. The synthesized CZA:Eu3+ phosphor can be used as a material that can increase the light absorption efficiency of the solar cell by converting ultraviolet or visible light down conversion into a wavelength in the near-infrared region.

Electrochemical Properties and Adsorption Performance of Carbon Materials Derived from Coffee Grounds (커피찌꺼기로부터 얻어진 탄소 소재의 전기화학적 성질 및 흡착 성능)

  • Jin Ju Yoo;Nayeon Ko;Su Hyun Oh;Jeongyeon Oh;Mijung Kim;Jaeeun Lee;Taeshik Earmme;Joonwon Bae
    • Applied Chemistry for Engineering
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    • v.34 no.5
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    • pp.529-533
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    • 2023
  • The fundamental electrochemical properties and adsorption capabilities of the carbonized product derived from coffee grounds, a prevalent form of lignocellulose abundantly generated in our daily lives, have been extensively investigated. The structure and morphology of the resultant carbonized product, obtained through a carbonization process conducted at a relatively low temperature of 600 ℃, were meticulously examined using a scanning electron microscope. Raman spectroscopy measurements yielded a relative crystallinity (D/G ratio) of the carbon product of 0.64. Electrical measurements revealed a linear ohmic relationship within the carbonized product. Furthermore, the viability of utilizing this carbonized material as an anode in lithium-ion batteries was evaluated through half-cell charge/discharge experiments, demonstrating an initial specific capacity of 520 mAh/g. Additionally, the adsorption performance of the carbon material towards a representative dye molecule was assessed via UV spectroscopy analyses. Supplementary experiments corroborated the material's ability to adsorb a distinct model molecule characterized by differing surface polarity, achieved through surface modification. This article presents pivotal findings that hold substantial implications for forthcoming research endeavors centered around the recycling of lignocellulose waste.

Effects of Dieatry Phytase on Performance, Excretion and Retention of P, and Ileal and Feces Digestibility in Broilers (Phytase 수준별 급여가 육계의 생산성, 인의 배설과 흡수 및 회장과 분에서 소화율에 미치는 영향)

  • HwangBo, J.;Ahn, J.H.;Chung, W.T.;Ohh, S.J.;Lee, H.J.;Kim, W.;Lee, S.U.;Hong, E.C.
    • Korean Journal of Poultry Science
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    • v.34 no.3
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    • pp.207-215
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    • 2007
  • This work was carried out to assess the effect of microbial phytase (MP) on the performance, retention and excretion of phosphorus, and nutrients availability in broiler chicks. Two hundred and sixteen one day old Ross strains broiler chicks were used to investigate on performance for 5 weeks (earlier $(0{\sim}2wk)$, finisher $(3{\sim}5wk)$) and were divided 3 treatments, three cages per treatment and 12 birds per cage. Treatments are P0 (basal diet), P1 (microbial phytase 300 FTU/kg), and P2 (microbial phytase 600 FTU/kg). After 5 weeks, three diets containing 0, 300, 600 FTU/kg of microbial phytase were fed to 5-wk-old broilers to assess the digestibility. Twenty seven broilers were divided into 3 treatments (9 birds per treatment) to investigate on the absorption and retention of phosphorus and nutrient digestibility. Body weight gain and feed efficiency were highly significant at P1 and P2 treatments compared to those of P0 (P<0.05), however, feed intake was no significant difference among all treatments (P>0.05). The excretion of phosphorus decreased in P1 and P2 compared to P0 (P<0.05). The digestibility of nutrients and amino acid was high in P1 and P2 treatments compared to P0 (P<0.05). Ileal digestibility was lower about $1{\sim}2%$ than feces digestibility (P>0.05). Finally, microbial phytase influenced on the performance, the retention and excretion of phosphorus and ileal and feces digestibility in broilers.

Heating Performance Analysis of the Heat Pump System for Agricultural Facilities using the Waste Heat of the Thermal Power Plant as Heat Source (발전소 폐열을 이용한 농업시설용 히트펌프시스템의 난방 성능 분석)

  • Kang, Youn Koo;Kang, Suk Won;Paek, Yee;Kim, Young Hwa;Jang, Jae Kyung;Ryou, Young Sun
    • Journal of Bio-Environment Control
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    • v.26 no.4
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    • pp.317-323
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    • 2017
  • In this study, the heating performance and the energy saving effect of the heat pump system using hot waste water(waste heat) of the thermal power plant discharged from a thermal power plant to the sea were analyzed. The greenhouse area was $5,280m^2$ and scale of the heat pump system was 120 RT(Refrigeration Ton), which was divided into 30 RT, 40 RT and 50 RT. The heat pump system consisted of the roll type heat exchangers, hot waste water transfer pipes, heat pumps(30, 40, 50 RT), a heat storage tank and fan coil units. The roll type heat exchangers was made of PE(Poly Ethylene) pipes in consideration of low cost and durability against corrosion, because hot waste water(sea water) is highly corrosive. And the heating period was 5 months from October to February. During the heating performance test(12 hours), the inlet water temperature of evaporator was changed from $32^{\circ}C$ to $26^{\circ}C$, and heat absorption of he evaporator was changed from 175 kW to 120 kW. The inlet water temperature of the condenser rose linearly from $15^{\circ}C$ to $50^{\circ}C$, and the heat release of condenser was reduced by 40 kW from 200 kW to 160 kW. And the power consumption of the heat pump system increased from 30 kW to 42 kW. When the inlet water temperature of condenser was $15^{\circ}C$, the heating COP(Coefficient Of Performance) was over 7.0. When it was $30^{\circ}C$, it dropped to 5.0, and when it was above $40^{\circ}C$, it decreased to less than 4.0. It was analyzed that the reduction of heating energy cost was 87% when compared to the duty free diesel that the carbon dioxide emission reduction effect was 62% by recycling the waste heat of the thermal power plant as a heat source of the heat pump system.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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 fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are 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 general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, 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 is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.