• Computers and Concrete
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• 제19권5호
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• pp.489-499
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• 2017

Self-Compacting Concrete (SCC) is a new technology capable to flow without segregation or any addition of energy which leads to efficient construction and cost savings. In this study, the effect of replacing the Ordinary Portland Cement (OPC) with Fly Ash (FA) on the strength, durability of the concrete was investigated experimentally, and carbon footprint and cost were also assessed. Four different replacement FA ratios (0%, 20%, 40% and 60%) were used to create four SCC mixes. Standard test methods were used to determine the workability, strength, and durability of the SCC mixes including resist chloride ion penetration, water permeability, water absorption, and initial surface absorption. The axial cube compressive strength tests were performed on the SCC mixes at 1, 7, 14, 28 and 35 days. Replacing the OPC with FA had a significant positive impact on chloride iron penetration resistance and water absorption but had a considerable negative impact on the compressive strength. The SCC mix with 60% FA had 36.7% and 15.8% enhancement in the resistance to chloride ion penetration and water absorption, respectively. Evaluation of the carbon footprint and the cost of each SCC mixes showed the $CO_2$ emissions mixes 1, 2, 3 and 4 were significantly reduced by increasing the FA content from 0% to 60%. Compared with the control mix, the cost of all mixes increased when the FA content increased, but no significant differences were seen between the estimated costs of all four mixes.

• Journal of Animal Science and Technology
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• 제58권2호
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• pp.9.1-9.5
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• 2016

Background: Literature is lacking on the effects of feeding by-product feed (BF)-based silage on rumen fermentation parameters, nutrient digestion and nitrogen (N) retention in sheep. Therefore, this study was conducted to determine the effect of replacing rye straw with BF-based silage as a roughage source on ruminal parameters, total-tract apparent nutrient digestibility, and N balance in sheep. Methods: The by-product feed silage was composed of spent mushroom substrate (SMS) (45 %), recycled poultry bedding (RPB) (21 %), rye straw (11 %), rice bran (10.8 %), corn taffy residue (10 %), protected fat (1.0 %), bentonite (0.6 %), and mixed microbial additive (0.6 %). Six sheep were assigned randomly to either the control (concentrate mix + rye straw) or a treatment diet (concentrate mix + BF-based silage). Results: Compared with the control diet, feeding a BF-based silage diet resulted in similar ruminal characteristics (pH, acetate, propionate, and butyrate concentrations, and acetate: propionate ratio), higher (p < 0.05) ruminal NH3-N, higher (p < 0.05) ether extract digestibility, similar crude protein digestibility, lower (p < 0.05) dry matter, fiber, and crude ash digestibilities, and higher (p < 0.05) N retention (g/d) Conclusion: The BF-based silage showed similar energy value, higher protein metabolism and utilization, and lower fiber digestion in sheep compared to the control diet containing rye straw.

• 한국통신학회논문지
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• 제23권6호
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• pp.1443-1453
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• 1998

본 논문은 컴퓨터에 입력된 문자정보를 음성정보로 변환하기 위한 음성합성엔진에 관한 것이며, 특히 명료성의 향상을 위해 파형처리 음성합성방식을 이용한다. 음성합성엔진은 컴맨드 스트림의 제어에 따라 자연성의 향상을 위한 피치조절, 길이 및 에너지 등을 제어하며 음성합성단위로서 반음절을 사용한다. 엔진에서 사용 가능한 컴맨드를 프로그램하여 음성합성엔진에 입력함으로서 음성을 합성하는 빙식은 구문분석, 어휘분석 등의 하이레벨과 파형의 편집 가공 등의 로우레벨을 완전 분리하므로 시스템의 융통성과 확장성을 높인다. 또한 TTS시스템의 적용에 있어 각 모듈을 객체/컴포넌트(Object/Component)로 각 모듈이 상호 독립적으로 작동되도록 하여 쉽게 대체가 가능하다. 하이 레벨과 로우 레벨을 분리하는 소프트웨어 아키택처는 음성합성 연구에 있어 각각 여러 분야별로 독립적으로 연구수행이 가능하여 연구의 효율성을 높이며 여러 소프트웨어의 조합사용(Mix-and-Match)이 가능하여 확장성과 이식성을 향상시킨다.

• 자원ㆍ환경경제연구
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• 제26권4호
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• pp.549-575
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• 2017

앞으로 우리나라의 발전원 구성은 신정부의 에너지 정책에 따라 석탄화력과 원자력이 감소하고 가스복합과 신재생에너지가 증가할 것으로 예상되며, 그러한 변화로 도시가스 산업에도 변화가 있을 것이다. 본 연구에서는 발전원 변경에 따른 영향을 정량적으로 살펴보기 위하여 석탄화력과 원자력을 각각 가스복합과 연료전지로 대체하는 시나리오를 설정하여 시나리오별로 도시가스 산업이 다른 산업에 미치는 경제적 파급효과의 변화를 분석하였다. 이 과정에서 정책의 영향이 나타날 시점을 고려하여 2030년 산업연관표를 추정하여 분석을 실시하였다. 분석 결과 가스복합으로 발전원을 대체하는 경우는 전체 산업에 유발하는 생산이 감소하고 연료전지를 사용하는 경우 증가하는 것으로 나타났으며, 모든 시나리오에서 전체 산업에 유발하는 부가가치는 동일한 것으로 나타났다. 이러한 결과는 발전원 변경 시, 변경 영향이 상대적으로 작게 나타나며 진입장벽이 낮은 가스복합을 단기적으로 활용하고, 장기적으로는 경제적 파급효과가 큰 연료전지를 활용하는 방안이 적절함을 의미한다.

• Advances in concrete construction
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• 제11권5호
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• pp.357-365
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• 2021

High deformable concrete (HDC) elements have compressive strength rates equal to conventional concrete and have got a high compressive strain at about 20% to 50%. These types of concrete elements as prefabricated parts have an abundance of applications in the construction industry which is the most used in the construction of tunnels in squeezing grounds, tunnel passwords from fault zones or swelling soils as soft supports. HDC elements after reaching to compressive yield stress, in nonlinear behavior have hardening combined with increasing strain and compressive strength. The main aim of this laboratory and numerical research is to construct concrete elements with the above properties so the compressive stress-strain behavior of different concrete elements with four categories of mix designs have been discussed and finally one of them has been defined as HDC element mix design. Furthermore, two columns with and without implementing of HDC elements have been made and stress-strain curves of them have been investigated experimentally. An analysis model is presented for columns using finite element method adopted by ABAQUS. The results obtained from the ABAQUS finite element method are compared with experimental data. The main comparison is made for stress-strain curve. The stress-strain curves from the finite element method agree well with experimental results. The results show that the dimension of the HDC samples is significant in the stress-strain behavior. The use of the element greatly increases energy absorption and ductility.

• 한국건설순환자원학회논문집
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• 제10권4호
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• pp.506-513
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• 2022

본 논문에서는 탄소중립을 위한 일환의 연구로써 3가지의 산업부산물을 활용하여 시멘트 사용량에 대하여 80 %까지 대폭 대체한 4성분계 고유동 콘크리트의 품질특성을 평가하였다. 평가결과, 다량의 산업부산물을 혼합하여 시멘트 사용량을 80% 이상 감소시킨 배합에서 목표 성능을 만족하는 품질을 얻을 수 있었으며, 유동특성, 역학특성 및 내구특성의 경우 기존 기준 배합과 비교하여 다소 성능이 감소되는 경향이 나타났지만 소요성능 수준 이상의 성능을 만족할 수 있는 것으로 판단된다. 종합적으로 고려할 경우 고로슬래그 미분말 혼합량이 큰 4성분계 고유동 콘크리트가 상대적으로 우수한 성능을 보였다.

• Mass Spectrometry Letters
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• 제2권1호
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• pp.1-7
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• 2011

China's rapid economic growth has resulted in significant environmental side effects. Therefore, China has been interested in reducing her dependence on foreign oil and gas by developing technologies needed for hydrogen, in addition to her increasing energy mix of nuclear and renewable energy form, such as solar and wind power. There are three isotopes of hydrogen, i.e. protium (P or H), deuterium (D), and tritium (T). Both deuterium and tritium are important materials in nuclear fuel cycle industry. Tritium is one of the critical radioactive nuclides. Planning for and implementing contamination control as a part of normal operation and maintenance activities is an important function in any hydrogen facility, especially tritium facility. The development of hydrogen isotopes analysis is the key issues in this area. Mass spectrometry (MS) with medium (about 600) and high resolution (> 1,400) is commercially available; however, the routine analysis of hydrogen isotopes is done with low-resolution MS (< 200) in China. This paper summarizes the progress of MS measurement technology for hydrogen isotope abundance in China, focusing on our lab's research program and technical status. An analyzing method has been introduced for accurate measurement of tritium abundance in the H.D.T system by low resolution MAT-253 MS. The quotient of compression ratio coefficient is determined by building up equipment for laboratory-scale preparation of secondary standard gases and by considering the difference in sensitivity between hydrogen isotopes. The results show that the measured value is reproducible within the relative error range of 0.8% for gas samples of different tritium abundance.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.884-894
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• 2011

Effects of temperature, volatile content, particle diameter and solid input weight were investigated in the batch fluidized bed reactor using OCN703-1100 particle as oxygen carrier and Roto coal and char as fuels. Two solid fuels represented the best reactivity at different temperature, $900^{\circ}C$ for Roto coal and $950^{\circ}C$ for char, respectively. However, we selected $900^{\circ}C$ as the best operating temperature because the improvement of reactivity of char at $950^{\circ}C$ was negligible. Char represented better reactivity than Roto coal because char contains low volatile than Roto coal. For both solid fuels, reactivities were improved with increasing of the particle diameter. These results were explained by solid mixing tests in a transparent fluidized bed using two char particles having different particle size ranges and OCN703-1100 particle. The bigger particle showed better solid mixing with OCN703-1100 particle, and therefore, represented better reactivity. For both solid fuels, reactivities were improved with increasing of the solid input weight within the experimental conditions of this study because the weight of coarse particles increased with the solid input weight increased, and therefore, these coarse particles can mix well with the oxygen carrier.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2011년도 춘계학술발표회
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• pp.168-169
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• 2011

• Journal of Electrical Engineering and Technology
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• 제2권4호
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• pp.452-460
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• 2007

The interstate electric power system, as an alternative for energy cooperation under regional economic block, was fervently debated prior to the restructuring of electric power industries and rapidly expanded in many regions since the 1990s. Especially, electric power system interconnection in the Northeast Asia region may bring considerable economic benefits since this region has strong supplementation in resource holdings, load shape, fuel mix, and etc. In this paper, we implement the ORIRES model, proposed by ESI of Russia, in order to analyze the economic feasibility on the Northeast Asia Region Electrical System Ties (NEAREST) project.