• Journal of Animal Science and Technology
• /
• v.53 no.2
• /
• pp.113-118
• /
• 2011

This study was conducted to evaluate effects of enzyme complex on growth performance, nutrient digestibility, blood profiles and feed cost in growing pigs. Ninety-six pigs [(Landrace ${\times}$ Yorkshire) ${\times}$ Duroc, $22.96{\pm}0.79$ kg average initial body weight] were used in 42d growth assay. Dietary treatments included:1) HC (high energy and nutrient density diet), 2) CON (control, basal diet), 3) CE1 (CON + 0.05% enzyme complex) and 4) CE2 (CON + 0.1% enzyme complex). Four pigs were allotted per pen with six replicate pens per treatment by completely randomized design. The ADG was higher in CE1 and CE2 treatments than CON treatment (P<0.05). The ADFI was linearly increased by CE treatments compared to HC treatment. The CE1 treatment had highest DM, N and GE digestibility (P<0.05). Digestibility of DM, N and GE were quadratic enhanced by enzyme complex level. No differences were found among treatments for creatinine and BUN. The enzyme complex treatments (CE1 and CE2) showed lower feed cost/body weight gain than HC treatment. In conclusion, enzyme complex can improve ADG and reduce feed cost/body weight gain when low energy diet was used. Furthermore adding 0.05% enzyme complex had highest nutrient digestibility.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.3
• /
• pp.294-301
• /
• 2020

This study evaluated the burnability and hydration reaction of clinker burned with high Al₂O₃ content OPC to apply large amounts of industrial by-products in the cement manufacturing process. Specifically, after preparing a clinker with a high C₃A content by burning the OPC raw material with a high content of Al₂O₃ in a laboratory electric furnace, the burnability of the clinker was evaluated through XRD Rietveld analysis and polarization microscopy, and clinker hydration reactivity was reviewed through the Isothermal conduction calorimetry analysis and the cement compressive strength. As a result, the kiln burning temperature for the production of high Al₂O₃ content clinker lower, and the compressive strength was equal to or higher than OPC. Therefore it was confirmed the possibility to manufacturing energy-saving high Al₂O₃ content clinker using a large amount of industrial by-products.

• Applied Chemistry for Engineering
• /
• v.26 no.6
• /
• pp.686-691
• /
• 2015

A basic research for utilizing solid refuse fuel (SRF) based on changing SRF properties (RDF, RPF) and types (pellet, fluff) is demonstrated. Physicochemical characteristics of SRF and also changes in thermal decomposition depending on combustion time and emission gas (NOx, CO, HCl, etc) concentration were investigated for applications to waste energy sources. In conclusion, RPF is easy to pelletize, and has better combustion efficiency, higher LHV, higher thermal reduction, and short combustion time because it is composed of plastic wastes homogeneously. Also, fluff type samples have better combustion efficiency, and short combustion time because it has wider exposed surface area for combustion. It can also save energy consumption for pelletizing.

• Journal of Korea Water Resources Association
• /
• v.49 no.5
• /
• pp.431-438
• /
• 2016

Large energy consumption is one of the main weaknesses of RO desalination. A new method is proposed to reduce the energy consumption of RO desalination which depends on the salinity of the feedwater. Low salinity feedwater can be obtained using groundwater wells which extracts both fresh groundwater and subsurface sea water. Subsurface feedwater is advantageous in overcoming other problems associated with surface seawater intakes. Salinities of groundwater depend on a number of factors. In this work a new simulation-optimization model is proposed to identify well locations and pumping rates with would provide the required design flow rate with the minimum salinity. When groundwater is developed in a coastal area, the saltwater wedge advances inland and may contaminate existing groundwater wells, which must be prevented. The model can protect existing wells while developing minimum salinity feedwater. Examples are provided to demonstrate the usage of the model.

• Land and Housing Review
• /
• v.3 no.4
• /
• pp.399-406
• /
• 2012

One-third of total energy and 50% of $CO_2$ emissions arise from construction phase. Because of this global amount of energy consumption and $CO_2$ emission, we must do our best to solve this problem. But our existing ways of meeting this problem has focused on the energy consumption saving of the construction and dwelling stage. On the other hand, we has been treated too lightly for handling the $CO_2$ emissions problem during the maintenance management and the demolition process so far,. In this paper, we quantitatively predicted and evaluated the environmental load in each construction step during all life cycle. And, we developed the environmental load assessment program for each construction step. And we proposed the reliable decision support model for objective and reliable environmental load assessment and reduction. This result must help the development of construction technology and low carbon & green growth.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.352-352
• /
• 2013

국내 에너지 소비량의 21.6%가 건물 분야에 소비되고 있다. 창호는 벽체에 비해 8~10배 이상 낮은 단열 특성을 가지기 때문에 열 손실량이 크다. 유리는 창호를 이루는 요소 중 가장 큰 면적을 차지하고 있으며, 창호의 단열성능을 2배로 향상시키면 30% 이상 건물의 에너지 절감 효과를 가질 수 있다. 창호의 단열 성능을 향상시키기 위해서 Low-e(emissivity) 기술 연구가 진행 중이다. 이번 실험에서는 RF 마그네트론 스퍼터링 시스템을 사용하여 XG 유리기판 위에 ZnO박막을 증착하고, evaporator 장비를 사용하여 metal층인 Ag를 증착하였다. 그리고 다시 한번 ZnO박막을 증착하였다. Low-e 연구에 활용할 수 있는지를 확인하기 위해 XRD, AFM, 투과도를 측정하였다. ZnO박막의 증착 조건은 초기압력 $3.0{\times}10^{-6}$ Torr, 공정압력 $2.0{\times}10^{-2}$ Torr, RF파워 30 W, Ar gas는 50 sccm, 증착온도는 상온으로 하였다. Metal층인 Ag를 증착하기 위해 evaporator의 증착 조건은 Rotate rate 2 rpm, voltage 0.3V, 공정압력 $5.0{\times}10^{-6}$ Torr이며, 변수로 Ag두께를 3,5,7,9,11,13,15 nm로 하였다. AFM 측정결과 Ag두께가 증가할수록 RMS roughness값이 높아졌으며, 최소 0.71 nm의 거칠기를 가지는 것을 확인하였다. XRD분석결과 37도 부근의 피크가 발생하여 ZnO 박막이 결정질 구조임을 확인할 수 있었다. 그리고 UV-Visible-NIR 분광 광도계를 이용하여 광학적 투과를 측정한 결과 Ag두께가 13 nm일 때 가시광 영역의 투과도가 최대 75%, 적외선 영역의 투과도가 최소 28%로 좋은 차단 특성을 가지는 것을 확인하였다. 위 결과들로 ZnO 박막이 Low-e 기술에 활용될 수 있음을 확인하였다.

• Resources Recycling
• /
• v.28 no.2
• /
• pp.14-22
• /
• 2019

Development of technology makes LED an economical option because of lower energy consumption and better environmental impact. Because higher consumer demand the LED market is expanding rapidly due to its environment-friendly advantages. Expansion of LED application, development of various fusion technologies, the emergence of new markets, and the large-scale expansion of markets would lead to a large volume of e-waste generation with valorization potential. Currently, most of the generated waste being that landfilled and incinerated due to the absence of technology and management system. In this paper, we review the current status of LED waste recycling and analyzes the available recycling technologies.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.282-287
• /
• 2016

Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.

• International Journal of Highway Engineering
• /
• v.12 no.3
• /
• pp.103-111
• /
• 2010

Recently, usage bicycle has been encouraged to reduce energy consumption and $CO_2$. For this purpose, lots of bike road construction are planned. Typical type of pavement used in bikeroad such as asphalt concrete pavement, portland cement concrete pavement, colored pavement, soil pavement. However, these pavement types may need high construction cost comparing the required capacity of bike road. In this study, roller compacted concrete pavement which are economical and durable, are investigated to use as bike road pavement. The optimum compaction level and mix design of roller compacted concrete pavement are suggested by exploring strength test with various mixture ratio and compaction level, Also durability was examined based on freeze-thaw and scaling test. In addition, the cost and amount of carbon emission during in the construction of roller compacted concrete were evaluated and compare with the cost and carbon emission of typical portland cement concrete.

• Journal of the HCI Society of Korea
• /
• v.12 no.4
• /
• pp.65-73
• /
• 2017

While electricity demand is generally increasing, stably controlling supply is becoming a serious challenge because renewable energies are becoming popular and often their productions are dependent on the weather. The 'demand response' programs can be used to complement the problems of renewable energies, and therefore their role is becoming increasingly important. This study provides an analysis of a demand response pilot that was conducted in Korea. The study first focused on questionnaire surveys and in-depth interviews, and the data was used to perform a Technology Acceptance Model (TAM) analysis. The goal of the pilot was to have the residential users reduce their power consumptions when an energy reduction mission is issued during peak load hours. The experimental subjects consisted of two groups with different characteristics. Subjects in group A obtained smart meters as an optional function of IoT platform service provided by a mobile service company, and received a charge deduction as their compensation. Subjects in group B either voluntarily purchased smart meters as individuals or received them by participating in an energy self-sufficient village program that was run by a local government, and were entitled to a donation as their compensation. With the analysis, group A was found to fit the extended technology acceptance model that includes perceived playfulness in addition to perceived ease of use and perceived usefulness. On the contrary, group B failed to fit the model well, but perceived usefulness was found to be relatively more important compared to group A. The results indicate that the residential energy groups' behavior changes are dependent on each group's characteristics, and group-specific DR design should be considered to improve the effectiveness of DR.