• Journal of Biosystems Engineering
• /
• v.24 no.4
• /
• pp.309-316
• /
• 1999

This study was conducted to develop a large-scale rice polisher with double polishing stages for producing clean rice with high quality in rice processing complexs. The performance of the developed rice polisher was evaluated and improved. The results obtained from this study were as followings : 1. A large-scale rice polisher with double polishing stages was developed, which consisted of two polishing chambers(polishing part I and II), two spraying parts, a feeding part, power of 37kW, control panel, etc. Especially, the purpose of polishing part Iwere to uniformly mix white rice sprayed with water and to remove bran particles from the rice. the roller surface of the polishing part I was coated with chromium. 2. The capacity of the developed rice polisher was 4t/h. The broken rice rate of the polisher was less than 0.2%, compared with about 1% of others. 3. The whiteness increment of the developed polisher was 2.6~3.0% compared with about 2.3~2.5% of others. 4. The energy consumption of the developed polisher was 0.5kWh/100kg. 5. The developed polisher was improved with the angle change of screen slot of the polishing chamber I. The broken rice rate was reduced from about 0.5% to about 0.2% as the max. internal pressure of the polishing chamber II decreased by 0.4kg/$\textrm{cm}^2$ due to the increase of resistance in the polishing chamber I. The whiteness of the polisher showed more than 38~39. 6. The developed rice polisher showed high performance, compared with other domestic and foreign polishers.

• Journal of Environmental Impact Assessment
• /
• v.32 no.3
• /
• pp.157-165
• /
• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.6
• /
• pp.754-762
• /
• 1998

Exhaust emissions in diesel engine are affected by fuel properties but the reason for this is not clear. Especially the recent strong interest in using low-grade fuel demands extensibe investigation in order to clarify the exhaust emissions. Bio-Diesel oil has a great possibility to solve the pollution problem caused by the exhaust gas from diesel engine vehicles. The use of bio-oils in diesel engines has received considerable atten-tion to the forseeable depletion of world oil supplies. So bio-diesel oil has been attracted with attentions for alternative and clean energy source. The purpose of this paper is to evaluate the fea-sibility of the rice-bran oil for alternative fuel in a diesel engine with rgard to exhaust emis-sions.

• Journal of Biosystems Engineering
• /
• v.29 no.2
• /
• pp.121-130
• /
• 2004

This study was carried out to develop a miller to produce white embryo rice with functional nutrients by improving the conventional vertical miller. The effects of rice moisture content and the shaft revolution speed of the miller on germ(embryo) adherence rate, whiteness, broken rice rate, and cracked rice rate were investigated. Also, the effect of the mesh size of emery stones on the germ adherence rate was investigated. The vertical prototype miller was improved with the increasement of about 42% in producing white embryo rice at proper conditions(shaft revolution speed of 900 rpm, emery stones of mesh ＃50, processing capacity of 2.3t/h, zero outlet resistance, rice moisture content of 16.2%). The results were as follows: 1. The germ adherence rate of white rice was significantly influenced by the moisture content of brown rice. The germ adherence rate of white rice decreased rapidly with the increase of the moisture content of brown rice. When brown rice with moisture content of 13.2%, 14.5%, 15.2%, 15.4% was milled by the prototype with emery stones of mesh ＃35 and shaft speed of 900(1,100) rpm, rpm adherence rate of milled rice was 76.2%(70%), 69.2%(66%), 45.9(38%), 13.0(9%), respectively. 2. The whiteness of white rice milled by the prototype with emery stones of mesh ＃35 and shaft speed of 1,100(900)rpm increased from 27(23) to about 40, respectively, as the moisture content of brown rice increased from 13.2% to 17.2%. 3. The rate of broken rice of white rice milled at 900rpm decreased by 0.6∼1.0% compared with that at 1,100rpm when the moisture content of brown rice was less than 15.2%. 4. The germ adherence rate was increased by 10.3% and 11.0%, respectively when brown rice with moisture content of 16.2% and 15.5% was milled by the prototype miller with shaft speed of 900rpm and emery stones of mesh ＃50 instead of mesh ＃35. 5. Considering the germ adherence rate, broken rice rate, and whiteness of milled rice, the proper milling conditions of the prototype miller for producing embryo rice were the moisture content of about 15%, the processing capacity of 2.3t/h and minimum outlet resistance of 0Nㆍm with shaft speed of 900rpm and emery stones of mesh ＃50.

• Korean Journal of Environmental Agriculture
• /
• v.19 no.5
• /
• pp.433-441
• /
• 2000

A feasibility study was performed to examine the agronomic application of treated sewage on paddy rice culture by field experiment for two consecutive years. The domestic sewage was treated by the constructed wetland system which was in subsurface flow type and consisted of sand and macrophyte. The effluent of the wetland system was used for irrigation water. The effluent was diluted to maintain the total nitrogen concentration below $26mg{\cdot}L^{-1}$ in the first year and used without dilution in the second year experiment. Growth components and yields were compared against the CONTROL plot where conventional method was applied. And also, soil characteristics of the plots before and after reclaimed sewage irrigation were analyzed. Generally, addition of the treated sewage to the irrigation water showed no adverse effects on paddy rice culture, and even enhancement was noticed in both growth and yield. Irrigation of treated sewage after concentration adjusted with conventional fertilization showed the better result, and the yield exceeded that of CONTROL case where clean water was irrigated. Soil characteristics changed after irrigation, and significant EC increasing was observed for the reclaimed sewage irrigation plots. From this study, it appears that reuse of treated sewage, as supplemental irrigation water could be a feasible and practical alternative. For full-scale application, further study is recommended on the specific guideline of major water quality components in treated sewage for irrigation and public health.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.41 no.2
• /
• pp.44-54
• /
• 1999

Agricultural water quality standards were reviewed through rice culture using treated sewage irrigation . The seqage from school building of Konkuk University was treated by a constructed wetland system, and theeffluent of the systeml was irrigated for rice culutre after nutrient concentration adjusted by dilution. Average concentration of COD, SS, T-N and T-P in irrigated water was 22.3mg/$\ell$, 6.5mg/$\ell$, 25.8 mg/$\ell$and 2.2mg/$\ell$, respectively. Treatment include irrigation of adjusted effluent with conventional fertilization (TWCF), adjusted effluent with no fertilization (TWNF). and effluent of the wetland system as it was with no fertilization (SWNF). These treatment plots were compared with control plot irrigated by tap water with conventional fertilization (CONTROL). Other environmentals for rice culture were identical for all the plots. Among them, TWCF showed the best growth rate and the highest yield, and constituents in the harvested rice showed not much difference among them. Which implies that irrigation with relatively high nutrient concentration compared to the current water quality standards may cause no adverse effect on rice culture and could be even beneficial . Although T-N for this study was 25 times greater than the current standards, rice culture wasnot adversely affected by irrigatino water quality and even beeter results were observed than the CONTROL. It could be mistakenly that clean irrigation water produces better agricultural product, however, it is not necessarily true. Irrigation water with moderate nutrient concentration can enhance the plant growth, and better result might be expected. Therefore, peer review and modification if necessary are needed to the current agricultural water quality standards, especially for the nutrient components.

• Economic and Environmental Geology
• /
• v.54 no.4
• /
• pp.483-494
• /
• 2021

This study was carried out to investigate the feasibility of reducing clean cover soil using a flooded column test in arsenic-contaminated farmland reclamation of abandoned coal mine area that shows generally low or about worrisome level (25 mg/kg) of Korea soil environment conservation act unlike abandoned metal mine. During the monitoring period of soil solution for 4 months, chemical properties (pH, EC, ORP, Fe, Mn, Ca, and As) in each layer (clean soil cover and contaminated/stabilized soil) showed different variation. This result revealed that soil solution in stabilized or contaminated soil rarely affected that in cover soil. Whether stabilized or not, arsenic concentrations in the rice roots grown in the soil covers with the thickness of 40 cm decreased by 98% in compared with the that grown in the control soil. In case of the soil covers with 20 cm thickness on stabilized soil, it decreased by 80% and this was 22 percentage point higher than when the soil of lower layer was not stabilized. Thus, reducing clean cover soil could be possible in contaminated farmland soil reclamation if appropriate stabilization of contaminated soil is carried.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.07a
• /
• pp.253-258
• /
• 2003

국민 1인당 쌀 소비량은 '90년 119.6kg 이었으나, '02년 87.0kg으로 급격히 감소하는 추세를 보이고 있다. 이는 국민 소득수준의 향상과 식품소비구조의 변화에 따른 것으로 쌀의 소비확대를 위해서는 이제 소비자의 욕구를 충족하는 고품질의 쌀을 공급해야 할 시전에 와 있다. 현재 유통되고 있는 일반 백미의 경우 소비자가 밥을 짓기 위해서는 쌀을 씻어야하는 번거로움뿐만 아니라 쌀 중량의 약 15배의 물이 소요되고, 또한 이때 발생된 쌀뜨물이 수질오염의 원인이 되기 때문에 무세미가공 및 보급 필요성이 점차 높아지고 있다. (중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.07a
• /
• pp.209-214
• /
• 2002

현재 시중에 유통되고 있는 쌀의 표면에는 육안으로 잘 보이지는 않지만 가공과정에서 발생된 미세 쌀겨나 이물질이 다소간 부착되어 있기 때문에 이들로 인해 저장성 저하를 초래하고, 또 소비자가 밥을 짓기 위해서는 씻어야 하는 번거로움이 있다. 물론 미곡가공시설들이 깨끗한 쌀을 공급한다는 취지에서 연미기를 통과한 것을 청결미라는 브랜드로 보급하고 있지만, 이 쌀들이 과연 어느 정도의 청결도를 갖는지에 대해서는 생각해볼 여지가 많다. (중략)

• Korean Journal of Organic Agriculture
• /
• v.11 no.4
• /
• pp.75-92
• /
• 2003

Organic livestock farming in northern European regions has been expanded with the major animals of large ruminants using pastures and grass silages. Organic livestock farming in some European countries has been in rather short of productivity compared to the conventional livestock farming, however since the gap of productivity between organic and conventional livestock farming has been reported to be reduced when the efficiency of management would improve, organic livestock farming has a potential to develop as a clean livestock farming in the future. We expect that organic livestock farming be propelled to a future model of livestock farming in Korea too. As the schemes for realization of organic livestock farming in Korea, firstly a system for the consistent supply of organic feed should be established. Mountainous areas that represents 63 % of total area of Korea could be utilized for the production of organic forages. Uncultivated rice paddy and upland agricultural field could also be used for this purpose. The active application of organic agricultural by-products such as organic rice straw, organic rice bran and SO forth can be considered for organic livestock farming. Secondly, the replacement of anti-biotics for the management of animal diseases should be developed using natural products. Plants and microbes would be good sources of natural products. Thirdly, the realization of organic livestock farming may require a system for certification of the organic farms and consequently the experts to work on.