• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
• /
• pp.70-76
• /
• 1996

The purpose of this study is to investigate workability and strength of concrete containing rice husk ash. For this purpose, concrete with and without rice husk ash were tested and analyzed on the workability and the characteristics fo their strength such as compressive, tensile and flexural strength according to unit weight of binder. Also, performances of rice husk ash as an admixture of concrete were compared with those of silica hume being widely used for high-strength concrete. As a result, workability and strength of rice husk ash as an admixture of concrete were analogous to those of silica hume.

• Preventive Nutrition and Food Science
• /
• 제16권2호
• /
• pp.179-183
• /
• 2011

This study was conducted to determine the biological activities of 70% ethanol extracts from rice husks of nine rice cultivars in Korea. The relative antioxidant activities of rice husk extracts were evaluated by determining DPPH, ABTS radical scavenging activity and reducing power. The contents of total polyphenol, flavonoid and r-oryzanol were measured by spectrophotometric methods. Among the extracts of rice husks, Nokmi rice husks tended to have the most effective antioxidant activities compared to other rice husk varieties. Seolgaeng rice husk extract showed anti-proliferative activity against cancer cell lines (MCF7 and NCI-H460), and Hongjinju rice husk extract significantly exhibited mitogenic activity.

• Plant Resources
• /
• 제5권2호
• /
• pp.95-103
• /
• 2002

Microscopic techniques were used to observe the microstructure of rice husk. Microscopic examination showed that two main components of husk, lemma and palea consisted of outer epidermis, layers of fibers, vascular bundles, parenchyma cells, and inner epidermis, in sequence from the outer to the inner surface. The outer epidermal walls were extremely thick, highly convoluted and lignified. The underlying fibers were also thick-walled and lignified. Parenchyma cells were thin-walled and unlignified. Inner epidermal cells were also unlignified. The outer surface of both lemma and palea were conspicuously ridged, but the lower surface had a flat appearance. As part of a detailed study to characterize rice husk using microscopic and micro-analytical techniques, distribution of silica was also examined, and is presented elsewhere. Rice husk can potentially be used as a raw material for making composite products and the observations presented here form valuable background information for our future work related to product development.

• Journal of Biosystems Engineering
• /
• 제30권4호
• /
• pp.229-234
• /
• 2005

Kinetic friction coefficient, bulk density, dynamic and static angle of repose, and terminal velocity of rice husk at the moisture range 7 to $23\%$ w.b. were determined. It could lead to better design and operation of the processing machinery and handling facilities. Friction coefficient was determined from the horizontal traction force measured by pulling the container holding a mass of rice husk on various plate materials. Dynamic angle of repose was calculated from the photos of bulk samples piled by gravity flow on a circular platform. Static angle of repose was determined by measuring the side angle of the bulk material which was left in a cylindrical container after natural discharge of the bulk sample through a circular hole in the bottom plate. Kinetic friction coefficients of rice husk were in the range of $0.254\~0.410,\;0.205\~0.520,\;0.229\~0.400,\;and 0.133\~0.420$ on PVC, mild steel, galvanized steel, and stainless steel, respectively. Bulk density, dynamic and static angle of repose, and terminal velocity were in the range of $91.7\~98.3$ $kg/m^3$, $40.2\~47.6^{\circ},\;52.8\~83.7^{\circ},$ and $1.36\~1.73$ m/s, respectively. These physical properties of rice husk increased linearly as the moisture content increased.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
• /
• pp.906-917
• /
• 1996

This study was conducted to find possible application areas of the by-products generated from the incineration of rice husk. To this end, a pilot-scale rice husk incinerator system was constructed and its performed test was carried. Major findings are summarized as follows. 1. The rice husk incinerator system developed in this study performed satisfactory in terms of thermal efficiencies. At the optimum operating conditions, thermal conversion efficiency and heat exchanger efficiency was 97% ad 60%, respectively, while overall thermal efficiency of the system was 58%. Under all conditions tested, temperatures in the combustion chamber were quite uniform and crystallization of SiO$_2$ in the ash was negligible. 2. NOx and SOx content in the flue gas was well below the legal limit but the CO concentration was around the legal limit. 3. Thermal energy from combustion was successfully recovered by a heat exchanger to provide hot water, ash was found a good supplementary cementing m terial, and the flue gas also was an acceptable $CO_2$ supplier to greenhouses.

• 한국유기농업학회지
• /
• 제9권3호
• /
• pp.103-117
• /
• 2001

This study was inducted to investigate the effects of microbial fertilizers on the fields of young radish(Raphanus sativus L.), chemical components of plant and soil, and the microbial floras. Six microbial fertilizers, MPK+Husk+Palma, Husk+Palma, MPK+Compost, Compost, BIO Livestock Clean System(BLCS) cattle dropping, and Tomi were used. The yields of young radish were increased in six microbial fertilizer treatments. The fresh matter weight, the number of leaves, and the dry matter weight of young radish in BLCS cattle dropping treatment, the leaf length in MPK+Husk+Palma treatment, the sugar content in Husk+Palma treatment, arid the leaf width in Tomi treatment showed the highest amount, respectively. The effects of microbial fertilizers on chemical characteristics of young radish and soil were examined. Phosphoric acid amount of young radish in Tomi treatment was much higher than other treatments. Potassium amount of young radish showed high significance in all microbial fertilizer treatments compared with control, and shoved the highest in Compost treatment . Two components, phosphoric acid find potassium, in soil inoculated by microbial fertilizers showed significant. Phosphoric acid in the Tomi treatment and Potassium in Husk+Palma treatment were increased. The microorganic populations in soil inoculated with microbial fertilizers were examined. While the number of Bacillus in ceil was increased in MPK+Husk+Palma treatment, the numbers of total bacteria, actinomycetes, and fungi were increased in Tomi treatment.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
• /
• pp.25-26
• /
• 2019

The construction of adobe houses in flood prone areas is a common practice. These houses collapse when hydraulic loads from flood exerts on the houses. The failure occurs because the adobe brick lacks strength. In order to improve strength of adobe brick, the effects of agriculture waste therefore rice straw, rice husk and rice husk ash as a stabilizing agent have been explored in this paper. The compressive strength test and splitting test was conducted on the adobe specimens which were stabilized with 2% rice straws, 2% rice husk and 2% rice husk ash by the dry weight of soil. The results showed the improvement in strength and elasticity of specimens containing rice straws & rice husk. Whereas with the addition of rice husk ash, the adobe loses its strength and showed plastic behavior.

• Advances in environmental research
• /
• 제1권3호
• /
• pp.223-236
• /
• 2012

Biosorption of methylene blue (MB) from aqueous solution was studied with respect to the point of zero charge of coconut husk, dye concentration, particle size, pH, temperature, as well as adsorbent and NaCl concentration using coconut husk biomass. Amongst Langmuir and Freundlich adsorption isotherms studied, Langmuir adsorption isotherm showed better agreement. Pseudo second order kinetics model was found to be more suitable for data presentation as compared to pseudo first order kinetics model. Also, involvement of diffusion process was studied using intraparticle diffusion, external mass transfer and Boyd kinetic model. Involvement of intraparticle diffusion model was found to be more relevant (prominent) as compared to external mass transfer (in) for methylene blue biosorption by the coconut husk. Moreover, thermodynamic properties of MB biosorption by coconut husk were studied. Desorption of methylene blue from biomass was studied with different desorbing agents, and the highest desorption achieved was as low as 7.18% with acetone, which indicate stable immobilization. Under the experimental conditions MB sorption was not significantly affected by pH, temperature and adsorbent concentration but low sorption was observed at higher NaCl concentrations.

• 한국가구학회지
• /
• 제17권1호
• /
• pp.23-32
• /
• 2006

This study was carried out to explore a new application of traditional Hanji and obtain fundamental properties for producing Hanji wallpaper by incorporating ceramics from wood and rice-husk as an interior building material. The results of properties determined were summarized as follows: The addition of ceramics in Hanji paper reduced its apparent density, but increased bulk density due to the ceramic particles distributed on the surface and inside the fiber of Hanji wallpapers. In particular, woodceramic particles were specifically distributed on the fiber surface, while particles of rice-husk ceramics were permeated into the inside surface of fibers. The density of rice-husk ceramics were greater than that of woodceramics. The physical properties of Hanji wallpapers, such as breaking strength, wet breaking strength, burst strength, tear index and folding endurance were deteriorated with the addition of ceramics. However, the addition of woodceramics in the Hanji wallpaper resulted in better strength in most cases than that of rice-husk ceramics, except tear strength. Therefore, an optimum addition level of woodceramics into the wallpaper was found to be 5% on the basis of intensity. The addition of ceramics also prolonged the combustion time because it lowered air permeability and brightness of the wallpaper.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 봄 학술논문 발표대회
• /
• pp.156-157
• /
• 2022

The purpose of this study is to propose a 40MPa mortar mixed design model that applies the neural network theory to minimize wasted effort in trial and error. A mixed design model was applied to each of the 60 data using fly ash, blast furnace slag fine powder and thickened rice husk powder. And in the neural network model, the optimized connection weight was obtained by repeatedly applying it to the MATLAB. The completed mixed design model was demonstrated by analyzing and comparing the predicted values of the mixed design model with those measured in the actual compressive strength test. As a result of the mixed design verification experiment, the error rates of the double mixed non-cement mortar using blast furnace slag fine powder and rice husk powder at a height of 40MPa were 3.24% and 3.4%. Mixed with fly ash and rice husk powder had an error rate of 3.94% and 5.8%. The error rate of the triple mixed non-cement mortar of the rice husk powder, fly ash, and blast furnace slag fine powder was 2.5% and 5.1%.