• 한국세라믹학회지
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• 제14권4호
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• pp.236-241
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• 1977

Three kinds of specimen, consisting of the graded pyrophyllite particles alone, a substituent of 8 percent fire clay for the finer portion ($F_2$) of it, and 0.8 percent inorganic binder-added composite were prepared under the following conditions respectively; moisture content=4.5~5.0%, forming pressure=250kg/$\textrm{cm}^2$ and sintering temperature=1, 000~1, 30$0^{\circ}C$. The various properties such as modulus of rupture, apparent porosity, bulk specific gravity, pore size and pore distributiion were measured in order to collaborate with sintering phenomena. The results obtained are as follows: (1) Apparent porosity isgradually decreased with rising the sintering temperature to 1, 25$0^{\circ}C$. (2) The binder-added specimen showed the lowest value in porosity. (3) The optimum sintering temperature of specimens was considered to be 1, 25$0^{\circ}C$. (4) The wider differences between pore volumes of specimens could be obtained by method of mercurypenetration porosimeter than by the conventional method for porosity.

• Advances in environmental research
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• 제1권4호
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• pp.305-321
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• 2012

This study entails establishing reference standard sand in Nigeria for engineering and geoenvironmental research work. Sands from four geographical locations in southwestern Nigeria were examined for baseline geotechnical and mineralogical properties. A total of sixteen sand samples were collected. The samples were air dried and subjected to tests in accordance with standard specifications. The tests carried out were: specific gravity, grain size analysis, moisture content, bulk density, porosity, void ratio, chemical analysis, X-ray diffraction and Differential Thermal Analysis. The properties of the samples were compared with a standard (Ottawa sand in Illinois of the United States) in order to find out which of the four samples selected from southwestern Nigeria could serve as standard baseline sand. The results show that Igbokoda sand has geotechnical and mineralogical characteristics closest to Ottawa sand. It was therefore concluded that Igbokoda sand could be used as a standard baseline sand for research work in southwestern Nigeria and other parts of Nigeria since it needs little processing to bring it to the same level as standard baseline sand, like the Ottawa sand.

• Advances in environmental research
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• 제8권1호
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• pp.55-69
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• 2019

The generation of ferrous slag, an industrial by-product from the iron ore industry, results in serious environmental problems. The chemical compositions indicate 30-34% SiO₂, 30-34% CaO, 18-22% Al₂O₃ and 0.5-0.6% Fe₂O₃. The specific gravity, moisture content and pH are in the range of 1.3-1.65, 9.1-10% and 8.5-9.0 respectively. The major part of the slag is composed of sand-size particles. The problems of disposal of slag could be minimized by considering its use in various environmental engineering applications providing additional value to the by-product. This paper mainly focuses on the potential utilization and valorisation of ferrous slag in both water and wastewater treatments. It is effective for the treatment of water and wastewater containing nutrients, heavy metals and polluted river/stormwater.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.271-278
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• 2002

Soft ground has complex features in mechanic character of ground. Some problems about the settlement and transformation occur if the ground strength is comparatively weak and the depth is large. Therefore, we should consider physical and mechanical characters for safe, economical design and management. As the result of the course, we can compare them with those of field then solve the limitations which were came from the complex character of the soft ground. I have considered the soil's physical character (specific gravity of soil particles, moisture content, grain-size analysis etc) and mechanical character (direct shear test, consolidation, triaxial shear test etc), and then make out a linear interpolation by regression using the two, those and connection of the depth

• 산업기술연구
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• 제18권
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• pp.77-86
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• 1998

This study is to provide the useful data for the design and construction of the geotechnical engineering works by collecting and analyzing the soil properties of granite soil in the Kangwon Province. Data base was obtained from 92 field sites in the Kangwon province divided into 15 areas based on administration district. Total numbers of data were 478. Correlations between soil constants, especially compaction properties, were obtained by performing statistical analysis. Analyzed results were as follows. 1. Most of granite soil consists of SM and GM based on United Soil Classification System. 2. Mean gravity of granite soil is 2.65 3. High correlations between optimum moisture content and the maximum dry density, plasticity index and liquid limit are obtained. 4. Analyzed results between other soil constants show relatively low correlation. However, they show consistent trends matchable to geotechnical engineering senses.

• 한국농공학회지
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• 제34권E호
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• pp.1-11
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• 1992

Increasing national concern on nonpoint source pollution of surface and ground water Systems has led researchers and policy makers to develop certain agricultural Best Management Practices. As an initial step of broad study program above mentioned, this study reflected the effects of different tillage practice on bulk density and degree of saturation on two regional soils, namely Tama silt loam and Catlin silt loam. Results may help to clarify some of the conflicting findings on the impact of tillage systems on these parameters and it may also explain some of the reasons for specific role that different tillage systems play regarding nonpoint source pollution from agricultural fields.

• 자원리싸이클링
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• 제16권5호
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• pp.71-76
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• 2007

가정에서 분리 배출된 폐플라스틱은 일반적으로 수선별 등 분리선별 공정을 거친 후 종말품으로 회수되어, 현재 대부분이 매립이나 소각되고 있다. 혼합폐플라스틱 종말품의 경우 2006년 약 175만톤 발생된 것으로 예측되고 있으나, EPR실시 이후로 발생량은 2000년에 비해 2배 이상 크게 증가한 실정이다. 특히, 혼합폐플라스틱 종말품의 경우 PVC 함량(4 wt.% 이하)이 매우 높아 이들의 재활용에 커다란 제약이 되고 있다. 본 연구에서는 혼합폐플라스틱 종말품으로부터 풍력 및 습식 비중선별장치를 이용하여 폴리올리핀계 (PE, PP, PS) 플라스틱을 경량물로 회수하는 선별시스템을 개발하였다. 본 선별시스템은 풍력선별, 자력선별, 1단계 파쇄, 정량공급 및 습식 비중선별 공정으로 구성되어 있으며, 습식 비중선별 공정은 원심분리를 기본으로 혼합-세척-선별 및 탈수가 단일장치내에 집약된 특징이 있다. 또한, 본 연구에서는 연질 플라스틱의 분쇄 효율을 크게 개선한 파쇄기를 개발하였다. 개발된 습식 비중선별장치의 용량은 시간당 0.5 톤으로, 이를 이용하여 회수된 경량물의 PVC 함량은 0.3wt.% 이하이며, 경량 및 중량 회수물의 수분 함량도 각각 10% 이하를 달성하였다.

• 한국가구학회지
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• 제21권6호
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• pp.479-485
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• 2010

제주도 산지림 및 방풍림 삼나무 목재의 조직 특성, 생재함수율, 무기 함유물 농도 및 흑심재 발생률 조사를 통해 얻어진 결과는 다음과 같았다. 1. 흑심재의 발생률은 산지림의 나무에 비해 방풍림의 것에서 훨씬 더 높게 나타났다. 2. 생재함수율은 심재의 재색이 적갈색에서 흑색으로 변함에 따라 높아지는 것으로 드러났다. 3. 흑심재의 방사조직 내에 존재하는 무기 함유물인 $K_2O$와 CaO는 흑심재의 주요 형성 원인 가운데 하나인 것으로 여겨졌다. 4. 목재의 비중 및 기계적 성질은 제주도의 삼나무가 한반도 남부 지역의 삼나무에 비해 비교적 낮게 나타났지만 제주도 내의 방풍림과 산지림 나무 사이에서는 큰 차이를 보이지 않았다.

• 한국식품조리과학회지
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• 제28권6호
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• pp.763-771
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• 2012

Physicochemical and sensory characteristics of pound cakes containing Angelica gigas NAKAI(Korean Angelica) with various levels of rice flour were investigated in this study. There were significant differences in the specific gravity of dough, and it had the lowest value of 0.848 in the control group. The weight of pound cakes was significantly increased by addition of rice flour, but the volume, specific volume and baking loss rate were significantly decreased by addition of rice flour. The moisture content and pH of pound cakes were found to increase with increasing rice flour content. DPPH radical scavenging activity of the control group was 51.02%, whereas pound cakes with rice flour ranged from 51.90~55.75%. The L value of brightness was increased, but a and b values were decreased significantly by addition of rice flour. In all of items of texture, the control group was higher than those of the pound cakes prepared with various levels of rice flour. Sensory evaluation scores in terms of appearance, flavor, taste, texture and overall preference for pound cakes showed that 50% and 75% substituted sample groups were higher than those of the other groups. The results of this study suggest that addition of 50~75% rice flour is the best substitution ratio for Korean Angelica pound cakes.

• 한국식생활문화학회지
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• 제37권4호
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• pp.354-362
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• 2022

The purpose of this study was to investigate the possibility of using air potato (Dioscorea bulbifera) powder to make sponge cakes. The sponge cake batter was made by adding 0, 10, 20, 30, and 40% of air potato powder, and the resultant anti-oxidative properties and quality characteristics were analyzed. The study showed that the height, batter yield, and loss rate of sponge cakes decreased as increasing amounts of air potato powder were added, but the weight, viscosity, moisture content, and specific gravity increased. An evaluation of the color showed that the L and b values were highest in the control group but the a value was highest in the 40% group. There was no significant difference between samples in terms of cohesiveness, although the study showed a significant increase in the hardness, chewiness, and gumminess as the quantity of air potato powder in the sponge cakes increased. The total polyphenol content and DPPH radical scavenging activity increased noticeably as more air potato powder was added to the sponge cakes. The results thus showed that the study groups with the addition of air potato powder showed higher antioxidant activity than the control group.