• 한국분말재료학회지
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• 제2권2호
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• pp.135-141
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• 1995

As the first step of study on fabrication of ceramic powders from phytoliths in rice, especially in rice husks, pulverization method of rice husks and the properties of milled rice husks were investigated. Impact methods, such as ball milling, were not meaningful for pulverizing elastic and thin fabric structure of rice husks. The most effective one was cutting method. In the present work, a rotating knife cutting method was applied to pulverizing rice husks. A 40-mesh screen was inserted under the rotating knives. The most portion of the milled powder was found in -50/+100 mesh section. Morphology of the milled rice husks revealed that the husks larger than 70 mesh were flake-like shape, at -70/+100 mesh section relatively equi-axed shape, at -170/+325 mesh section rod-like shape, and below 325 mesh section dust-like shape. Tap density of raw rice husks was about 0.1 $g/cm^3$, while those of milled rice husks were over $0.4 g/cm^3$. This meant that, for a given volume of reactor, raw material charge can be increased more that 4 times when using milled rice husks than unmilled one. True densities of unmilled and milled rice husks were higher than $1.4 g/cm^3$, and increased with decreasing milled sizes.

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.13-20
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• 1998

Carbonized rice husk(char from rice husk) can be used to improve soils for planting, seedlings, horiculture, pomiculture and truck gardening. Although it is not a fertilizer in nature, it stimulates the growth of plants. Carbonized rice husk is highly recommended for raising soil/water temperature, keeping moisture and aerating roots of plants. The objective of this study was to develop the effective production method of carbonized rice husks by a non-slagging vertical cyclone combustor. A cyclone combustor w vortex collecor Pocket in addition to central collector pocket was selected and tested. Isothermal tests and mixed firing with LPG and rice husk were performed in order to characterize the system. hut rice husk was used during the isothermal test to find the mass collected of rice husk. It was impossible to ignite rice husk itself over the experimental conditions considered in this experiment. The composition of original and carbonized rice husks was analyzed by the ultimate analysis. With the air flow rate of 20 ㎥/h, LPG flow rate of 0.45 1/min, the required carbonized rice husk could be obtained.

• Journal of Biosystems Engineering
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• 제33권4호
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• pp.248-252
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• 2008

An experiment was conducted in order to investigate gasification characteristics of rice husks in a fixed bed, which was a pre-step to design a continuous gasification system. Two air supply levels for gasification were chosen and their effects on the producer gas amount and producer gas composition were discussed. The main components of the producer gas were CO, $CO_2$, $O_2$, $H_2$ and THC (Total HydroCarbon). As airflow rate decreased, more producer gas was produced. The peak amount of CO, $H_2$ and THC were 28%, 7.5% and 0.68% in volume when constant airflow rate of $3.36\;m^3/s$ was used in the batch operation. About 4.5 kg of ash (9%) and condensed water including tars of 6 kg (11%) were produced from 50 kg rice husks in the gasification. Excluding the byproducts, all rice husks seemed to be transformed into producer gas. This gasification study was conducted prior to developing a continuous gasification system for biomass including agricultural byproducts.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.511-518
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• 2017

최근의 단열 재료에 대한 관심과 연구는 단열성능 이외의 복합적 성능을 요구하는 추세이다. 본 연구에서는 구조적인 성능을 가지는 왕겨숯 보드 개발을 위한 목재 섬유대 왕겨숯의 최적 비율을 찾고자 하였다. 왕겨숯을 활용하여 구조적 성능을 지니는 친환경 단열재를 개발하고자 기초 연구를 실시하여 다음과 같은 결론을 얻었다. 최종 왕겨숯 보드의 함수율은 3.2~4.1%로 얻어졌으며, 밀도는 0.58~0.68로 우수한 구조재료로서의 가능성을 보였다. 휨강도는 길이방향으로 9.1-32.6 MPa, 그리고 폭방향으로는 9.2-34.1 MPa로 나타났다. 통상적으로 사용되는 MDF 수준의 휨강도를 얻을 수 있어 구조적 성질을 가지는 단열재 개발의 가능성을 찾을 수 있었다.

• Journal of Animal Science and Technology
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• 제65권2호
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• pp.377-386
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• 2023

The effect of different commercially available bedding materials on the growth performance and carcass characteristics of ducks for 42 days was investigated. 336 one-day-old White-Pekin ducklings (60.48 ± 0.16 g) were randomly allocated into 24-floor pens with one of the three beddings namely i) coco peat, ii) rice husks, or iii) sawdust. 14 ducklings per pen and 8 replicate pens per bedding material were used. Birds were fed a starter diet from days 1-21 and a grower diet from days 22-42. Weekly growth performance evaluation was conducted for the average body weight, weight gains, daily feed intake, and feed conversion efficiency. One bird per pen was sacrificed on day 42 for the evaluation of carcass characteristics including the carcass, breast, and leg muscle percentages. Breast and leg muscle samples were then collected and analyzed for their proximate and pH values. Higher body weights (p < 0.05) were noticed with rice husks on day 42 only. Improved daily gains (p < 0.05) were also noticed for birds raised with rice husks over the entire period (days 1-42). Concerning feed intake, higher values (p < 0.05) were similarly noted with rice husks for the grower phase (days 22-42), and the entire experimental period (days 1-42). Marginally improved feed intake values were also noted with the use of rice husks as the bedding materials on day 42 (p = 0.092). Improved feed efficiency (p < 0.05) was noticed with rice husks on day 35, the grower period, and the entire 42-day period. However, no significant differences were noticed for most of the carcass characteristics that were evaluated. Nevertheless, higher (p < 0.05) pH values for the breast muscle were noticed with the use of coco peat and sawdust as the bedding. Conclusively, the bedding type could have a significant impact on the growth performance of ducks without adverse effects on carcass characteristics. The use of rice husks as bedding might be advantageous and is therefore recommended.

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

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.226-226
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• 2017

This study was to evaluate methods to high quality food ramie rice cake, thereby increasing farm income. This study investigated the effects of different covering material on stable winter survival management with edible leaf in Ramie(Boehmeria nivea L.). The method of winter survival with covering material were conducted under three condition compose to Non covering, Rice straw cutting covered with 500kg.10a-1, Rice husks covered with 1,000kg.10a-1(covered 4~5 cm thickness in the soil surface). Method of application were standard application(N-P-K-Compost applied at 27-9-27-600kg.10a-1. Compost and fused phosphate applied at 100% of basal fertilizer in March 25. 20% of top dressing were four times application in March 25 - October 5. Planting year were March 15, 2011. Plants were spaced 60 cm apart in rows 25 cm apart with open cultivation. According to non covering < Rice husks covered with 1,000kg.10a-1 < Rice straw cutting covered with 500kg.10a-1 cultivation this order, aerial part as a result were plenty amount of growth. Sprout time and winter survival rates was uncovering control plot compared to 2 - 5 days quickly, 45-57% highly by rice husks and rice straw covering. Green leaf yields is untreated control plot (12,44 kg.10a-1) compared to rice husks covering 7% higher, and rice straw covering increased to 18% of the most.

• 한국결정성장학회지
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• 제26권5호
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• pp.188-192
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• 2016

본 연구에서는, 실리카 분말과 왕겨의 혼합체로부터 탄화된 물질로부터, 탄화규소 (SiC) 분말이 합성되었다. 탄화왕겨와 실리카의 열탄화환원 반응을 통해 얻어진, SiC 시료는 XRD 회절 패턴, FE-SEM 및 FE-TEM을 통해 분석되었다. 시료들은 XRD 패턴에서, $35^{\circ}$ 부근의 (111) peak는 매우 높은 intensity를 나타내었고, $60^{\circ}$, $72^{\circ}$ 부근의 (220), (311) peak 등 탄화규소 결정상에 대한 peak pattern이 명확하게 관찰되었다. Ar 분위기에서 탄화왕겨와 실리카의 혼합비율이 6 : 4인 혼합물로부터 합성된 시료는 XRD 패턴에서 잔류카본이 검출되지 않았으며, hexagonal 결정상의 비율이 비교적 낮고, cubic SiC 결정상이 주도적으로 나타내었다. 탄화왕겨와 실리카의 혼합비율이 6 : 4인 경우에 합성된 시료는 $5{\mu}m$ 이하의 미세한 입자들이 관찰되었으며, TEM 분석결과에서, SiC 결정질상의 (110) 회절패턴 형태를 나타내었다.

• 한국결정성장학회지
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• 제29권2호
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• pp.45-49
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• 2019

본 연구에서는, 탄소성분으로서 탄화왕겨, 제지슬러지, 커피찌꺼기와 실리카 분말로부터, 비교적 미세한 탄화규소 결정질 응집체를 합성하였다. 탄소성분들과 실리카의 혼합물로부터 탄화규소 응집체를 얻기 위한 주요 반응물질은 열탄화환원 반응에 의해 생성된 일산화규소 기체로 추정되었다. 탄화왕겨, 제지슬러지, 커피찌꺼기와 실리카 분말의 혼합물로부터 열탄화환원반응법을 거쳐 생성된 탄화규소 결정질 응집체들에 대한 XRD 회절패턴으로부터 결정상을 분석하였고, FE-SEM과 FE-TEM을 통한 미세구조, 결정구조 분석이 이루어졌다. 탄화왕겨, 제지슬러지, 그리고 실리카 분말의 시료의 경우, XRD 분석에서는 $35^{\circ}$ 부근의 (111) peak은 비교적 높은 강도를 나타내었다. 탄화왕겨, 제지슬러지, 커피찌꺼기와 실리카 분말의 혼합물로부터 합성된 시료들에 대해 FE-SEM 관찰을 통하여 $1{\mu}m$ 이하의 미세입자들을 관찰하였으며, TEM 측정 결과에서는 탄화규소 결정질상의 (110) 회절패턴들을 확인하였다.

• 한국분말재료학회지
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• 제3권2호
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• pp.112-119
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• 1996

Using rice husks pulverized by rotating knife cutter, the raw rice husk powder was solution treated by nitric and hydrochloric acids in order to separate phytolith from organic constituents. Because of the strong resistance of organic components of rice husk to acids, the raw powder had to be boiled in concentrated acids up to 300 min. By boiling in nitric acid for 60~120 min, all organic components were resolved while amorphous silica Powder of about 20 nm in size and of higher than 99.8% in purity was left behind. Inferior to the nitric acid, hydrochloric acid was not able to resolve organic component completely leaving unresolved matter of about 40% by weight even after 300 min of boiling. From the acid treatments and impurity analyses, it is considered that most of metallic elements in rice husks are combined to organic components that are easily soluble to acids.