• Advances in concrete construction
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• 제13권6호
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• pp.423-431
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• 2022

Although the influence of moisture content on the mechanical properties of concrete has been studied for a long time, research related to its influence on the damping and energy dissipation property of concrete structure is still very limited. In this paper, the relationship between damping property and moisture content of concrete using cyclic uniaxial compression is firstly presented, and the mechanism of the influence of moisture content on concrete damping and energy dissipation capacity is analyzed. Based on the experimental research, moisture-related damping and energy dissipation model is proposed. Results show that the dissipated energy of concrete and loss factor increase as the moisture content increasing. The energy dissipation coefficient reflecting the influence of stress level of concrete under cyclic load, decreases first and then increases as the moisture content increasing. The mechanism of moisture-related energy dissipation behavior can be divided into the reactive force of water, the development of the internal micro cracks and the pore water pressure. Finally, the proposed moisture-related damping and energy dissipation model are verified.

• 한국산림과학회지
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• 제99권5호
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• pp.706-710
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• 2010

Understanding of chemical composition and energy contents in tree is important to develope strategies of renewable energy policy to cope with climate change. Residual biomass as renewable energy source was evaluated and focused on the bark-containing branches. Chemical analysis studies were conducted for different part of yellow poplar (Liriodendron tulipifera), which were partitioned to inner bark, outer bark, small branches, medium branches, big branches and trunk. The variations in hydrophobic extractives, hydrophilic extractives, lignin, carbohydrate compositions, energy contents (higher heating value) and the ash content were determined. The inner and outer bark had higher ash content, hydrophobic and hydrophilic extractives content, and higher energy content than those of tree trunk. Polysaccharides content in inner and outer bark was quite lower than those of stem or branches. Based on the energy content of residual biomass, replacement of fossil fuel and greenhouse gas emission abatement were calculated.

• Applied Biological Chemistry
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• 제7권
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• pp.29-33
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• 1966

이 시험(試驗)은 쥐오줌의 energy value와 nitrogen content와의 관계(關係)를 연구(硏究)하기 위하여 행(行)하여졌다. 이 시험(試驗)을 위하여 ad lib.구(區)에 13 마리, 2 meals구(區)에 16 마리, 도합(都合) 29 마리의 쥐가 쓰였다. 오줌의 채집(採集)은 22 일간(日間)의 본시험기간중(本試驗期間中) 8 일(日)동안 행(行)하였다. 1 일(日) 2회(回) 채식(採食)시킨 쥐들이 훨씬 많은 (p<0.05) nitrogen 을 배설(排泄)했고 아울러 더 많은 energy를 배설(排泄)하였다. 쥐오줌의 energy concentration과 nitrogen content 사이에는 직선관계(直線關係)가 있어서 nitrogen 함량(含量)이 증가(增加)하면 energy의 배설량(排泄量)이 증가(增加)된다는 사실(事實)이 밝혀 졌다. urinary nitrogen(X, gm/100 ml)으로 부터 energy value (Y, kcal/100 ml)를 산출(算出)할 수있는 공식(公式)을 유도(誘導)했는데 다음의 식(式)은 일반적(一般的)으로 이 목적(目的)을 위하여 쓰여질 수 있는 것으로 본다. Y=8.924X+0.182 (Y=urinary energy, X=urinary N) 이러한 산출(算出)에 수반(隨伴)도는 표준오차(標準誤差)는 0.788 kcal이다. nitrogen content로부터 energy concentration을 산출(算出)하는데 따르는 오차(誤差)가 이렇게 적기 때문에 또 urinary energy의 함량(含量)이 GE, DE, ME, 섭취량(攝取量)에 비(比)해 적기 때문에 유사(類似)한 Diet를 공급(供給)하는 경우(境遇) 이 식(式)은 쥐오줌의 energy value를 산출(算出)하는데 쓰일 수 있을 것이다. 따라서 오줌의 energy value의 직접측정(直接測定)에 소요(所要)되는 많은 시간(時間)과 노력(努力)이 절약(節約)되는 것이다. 쥐오줌의 energy: nitrogen의 비(比)는 9.4(ad lib.구(區)) 내지(乃至) 8.6(2 meals 구(區))으로서 채식회수(採食回數)는 이 비율(比率)에 하등(何等)의 영향(影響)이 없음이 밝혀졌다.

• 한국산림과학회지
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• 제95권3호
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• pp.299-308
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• 2006

본 연구는 위도와 해발고에 따른 우리나라 신갈나무림의 에너지 고정량을 알아보기 위해 강원도 평창군 중왕산 지역(해발 1,300 m, 1,000 m, 800 m), 경기도 광주시 태화산 지역(해발 350 m), 충청북도 제천시 월악산 지역(해발 300 m), 전라남도 광양시 백운산 지역(해발 800 m), 제주도 서귀포시 한라산 지역(해발 1,000 m)을 대상으로 수행되었다. 우리나라 신갈나무림의 에너지량은 2,916~6,550 GJ/ha이고, 연간 에너지 고정량은 250~440 GJ/ha이다. 신갈나무림의 에너지량과 연간 에너지 고정량은 위도가 낮아질수록 더 많아지는 것으로 나타났다. 해발고가 낮을수록 신갈나무림의 에너지량은 증대되는 것으로 나타났다. 신갈나무림의 연간 에너지 고정량과 환경 인자간의 상관관계는 온도, 해발고, 임령, 사면 등의 순서로 크게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제5권1호
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• pp.129-138
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• 1992

The effects of dietary levels of lysine and energy on growth performance, the content of DNA, RNA and protein in liver, thigh muscle composition and nutrient utilization in broiler chicks were investigated in an experiment involvies with 2 levels of dietary energy : 3,200 (2900) 2,900 (2700) kcal ME/kg) and 6 levels of lysine : 0.6(0.5), 0.8(0.7), 1.0(0.9), 1.2(1.1), 1.4(1.3), and 1.6(1.5)% was carried out. A total number of 384 male broiler chicks was used for a period of 7 weeks. Body weight gain of 1.0(0.9)% lysine level group was significantly (p < 0.01) higher than that of any other groups. Interaction between lysine and energy in the feed intake was observed (p < 0.05). Present data indicate that the content of DNA in liver tissues was significantly (p < 0.05) different by the levels of lysine, namely, 1.0(0.9)% or 1.2(1.1)% lysine level groups showed higher content than other groups (p < 0.01). Dietary levels of 1.2(1.1)% or 1.6(1.5)% lysine groups showed the highest protein content in thigh muscle tissues than that of any other groups (p < 0.05). Interaction between energy and lysine in the content of protein of thigh muscle tissues was shown (p < 0.01). The level of 0.6% lysine group showed the highest fat content in thigh muscle tissues than any other groups. Interaction between lysine and energy in the content of crude ash and crude fat of thigh muscle tissues was observed (p < 0.01). Apparent amino acid availability of arginine, glycine and threonine (p < 0.01), phenylalanine (p < 0.05) were significantly affected by the levels of lysine and interaction between lysine and energy was found only in arginine (p < 0.01).

• 한국수소및신에너지학회논문집
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• 제24권4호
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• pp.340-346
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• 2013

Study on clean and efficient utilization technology for low rank coal with high moisture content is actively ongoing due to limited reserves of petroleum and of high grade coal and serious climate change caused by fossil fuel usage. In the present study, supercritical water gasification of low rank coal was performed. With increasing reaction temperature, content of combustible gases such as $H_2$ and $CH_4$ in the syngas increased while the $CO_2$ content decreased. As the reaction pressure increased from 210 to 300 bar, the $CO_2$ content in the syngas increased while the hydrocarbon gas content decreased. The $H_2$ and $CH_4$ content in the syngas increased slightly with pressure. With the addition of Pd, Pt, and Ru catalysts, it was possible to improve the production of $H_2$. Moreover, the increase of active metal content in the catalyst increased the $H_2$ productivity. The Ru catalyst shows the best performance for increasing the $H_2$ content in the syngas, while decreasing the $CO_2$ content.

• Advances in concrete construction
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• 제16권6호
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• pp.277-290
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• 2023

In order to study the mechanical properties of basalt fiber reinforced ultra-fine fly ash concrete (BFUFARC), the effects of ultra-fine fly ash (UFA) content, basalt fiber content, basalt fiber length and water reducing agent content on the compressive strength, splitting tensile strength and flexural strength of the composite material were studied through experimental and theoretical analysis. Also, a scanning electron microscope (SEM) was employed to analyze the mesoscopic structure in the fracture surface of composite material specimens at magnifications of 500 and 3500. Besides, the energy release rate (G_c) and surface free energy (γ_s) of crack tip cracking on BFUFARC in different basalt fiber content were studied from the perspective of fracture mechanics. Further, the cracking resistance, reinforcement, and toughening mechanisms of basalt fibers on concrete substrate were revealed by surface free energy of BFUFARC. The experimental results indicated that basalt fiber content is the main influence factor on the splitting tensile strength of BFUFARC. In case that fiber content increased from 0 to 0.3%, the concrete surface free energy at the tip of single-sided crack showed a trend of increased at first and then decreased. The surface free energy reached at maximum, about 3.59 × 10^-5 MN/m. During the process of increasing fiber content from 0 to 0.1%, G_C-2_γS showed a gradually decreasing trend. As a result, an appropriate amount of basalt fiber can play a preventing cracking role by increasing the concrete surface free energy, further effectively improve the concrete splitting tensile performance.

• 한국가구학회지
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• 제19권5호
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• pp.350-357
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• 2008

This research investigates the bending properties to predict the work-energy to maximum load and impact bending energy from static bending and impact bending test. Specimens were prepared from lumber made of thinning crop-trees. Matched specimens were used for MC 12% and green moisture specimens to measure the effect of moisture content on the absorbed energy from static and impact bending tests. The bending properties such as MOE, MOR, etc. is a good predictor to investigate the work-energy and work-energy per unit volume from static bending and impact bending test. The impact bending energy is increased with increasing moisture content. However, the work to maximum load from static bending test is increasing with increasing the MC only for higher density species.

• 신재생에너지
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• 제19권4호
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• pp.27-34
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• 2023

In this study, microalgal oil was extracted from Nannochloropsis oceanica cultured in an open raceway pond and converted into biodiesel using a solid acid catalyst. Microalgal oil was extracted from two types of microalgae with and without nitrogen starvation using the KOH-solvent extraction method and the fatty acid content and oil extraction yield from each microalgae were compared. The fatty acid content of N. oceanica was 184.8 mg/g cell under basic conditions, and the oil content increased to 340.1 mg/g under nitrogen starvation conditions. Oil extraction yields were 90.8 and 95.4% in the first extraction, and increased to 97.5 and 98.8% after the second extraction. Microalgal oil extracted by KOH-solvent extraction was yellow in color and had reduced viscosity due to chlorophyll removal. In biodiesel conversion using the catalyst SO₄^2-/HZSM-5, solvent-extracted oil showed a FAME content of 4.8%, while KOH-solvent-extracted oil showed a FAME content of 90.4%. Solid acid catalyst application has been made easier by removal of chlorophyll from microalgal oil. The FAME content increased to 96.6% upon distillation, and the oxidation stability increased to 11.07 h with addition of rapeseed biodiesel and 1,000 ppm butylated hydroxyanisole.

• 한국세라믹학회지
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• 제24권6호
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• pp.586-592
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• 1987

The role of the strain energy and phase stability in the diffuse phase transition have been investigated in the highly disordered solid solution, (Pb1-xBax)(Zr0.4Ti0.6)O3 (0.2 x 0.4). X-ray diffraction analysis indicates that tetragonality (c/a) decreases with the increasing Ba content. Also as the Ba content increases, phase transition becomes more diffuse and at the same time dielectric relaxation as a function of measured frequencies in the 1KHz-10MHz range occurs very pronouncedly. In the Ba content range, 0.2 x 0.35, hysteresis loops are routinely observed and the loop is observed to narrow shape as the Ba content increases but becomes very slim at 40mol% Ba content. Moreover thermal analysis shows that there is no abrupt change in the thermal expansion coefficient below the apparent transition temperature at which dielectric constant becomes maximum. From the above results, it has been concluded that creation of the strain energy due to the distorthion that occurred during the phase transition suppresses diffuse phase transition.