• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1998.06b
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• pp.234-240
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• 1998

• Food Science and Preservation
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• v.22 no.5
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• pp.652-659
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• 2015

The physical properties of wheat kernels were determined as a function of moisture content to optimize the design of equipment for post-harvest management. Several properties, including bulk density, dynamic repose angle, one thousand-kernel weight, specific gravity, length, width, thickness, and area of two wheat cultivars (Baekjjung: B and Jogyeong: J ), were studied in the moisture range from approximately 9% to 30% wet basis. As moisture increased, length increased linearly from 6.42 to 7.20 mm (B) and 8.71 to 9.15 mm (J), width increased from 2.90 to 3.49 mm (B) and 4.12 to 4.43 mm (J), thickness from 2.94 to 3.20 mm (B) and 3.29 to 3.63 mm (J), and area from 14.13 to $19.44mm^2$ (B) and 27.75 to $31.25mm^2$ (J). Additionally, the dynamic repose angle and one thousand-kernel weight increased linearly from $46.3^{\circ}$ to $54.0^{\circ}$ (B) and $46.3^{\circ}$ to $54.5^{\circ}$ (J) and from 32.26 to 41.51 g (B) and 45.30 to 63.07 g (J), respectively, as the moisture content increased. Based on the experimental measurements, only the bulk density and specific gravity decreased from 754.0 to $664.1kgm^{-3}$ (B) and 776.1 to $660.0kgm^{-3}$ (J) and from 1.2950 to 1.2265 (B) and 1.3379 to 1.2671 (J), respectively, as moisture content increased.

• Journal of Animal Environmental Science
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• v.5 no.3
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• pp.197-202
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• 1999

퇴비화 재료를 혼합하는 목적은 재료를 퇴비황에 최적조건으로 조성하여 퇴비화 성능을 향상 시키고 취기발생을 억제하기 위함이다. 퇴비화성능에 미치는 요인으로서는 C/N비, 수분 함량, 산도(pH), 산물밀도, 입자크기 등이 있다. 이 중에서 C/N비는 적정값으로 조성하기 어렵다. 본 자료는 퇴비재료의 적정 수분 함량 및 C/N비를 조성하기 위해 각 요소재료의 혼합비율을 제시하고 있다.

• Korean Journal of Environmental Agriculture
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• v.16 no.3
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• pp.264-268
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• 1997

Microbial metabolites from rhizosphere soil samples mainly inhabitated by Streptomyces are selectively uptaken into plants. The culture broth of a Streptomyces strain K9301 showed a major metabolite which disappeared in the medium 24hrs after planting of seedlings. This metabolite was selectively uptaken in the rice plants as well as the wheat plants. We identified the targeted metabolite showing a strong UV-absorbing spot at Rf 0.6 on TLC to be 2-aminobenzamide.

• Journal of the KSME
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• v.32 no.11
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• pp.917-926
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• 1992

트라이볼로지의 핵심분야인 마찰, 마멸에 대해 간단히 살펴보았다. 과학의 급속한 발전에도 불 구하고 아직도 이들에 대한 완전한 지식은 아직 요원한 상태이다. 그러나 현재까지 알려진 지 식으로도 기계시스템의 최적설계에 크게 도움이 된다는 사실에 대해서는 의심의 여지가 없다. 앞에서 함께 살펴본 마멸 입자에 대한 소개는 마찰과 마멸의 복합적인 산물로서 이의 관찰을 통해 분석하고자 하는 기계시스템의 상태를 효과적으로 진단하여 트라이볼로지적 거동을 이해 하는 데에 중대한 정보가 된다. 따라서 마찰과 마멸에 대한 궁극적인 연구와 함께 그 산물인 마멸입자에 대한 보다 적극적인 이해와 지식의 축적은 요소(tribo-elements)의 고성능, 고정밀 화에 크게 이바지할 것이다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.317-326
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• 2003

원예산물은 출하과정에서 외관과 내부품질에 따라 분류되고, 그 결과에 따라 상품성과 가격이 결정된다. 수박의 경우에도 품질이나 가격은 크기, 무게, 외피모양, 타격할 때 나는 반사음, 촉감 등에 따라 결정되는데, 주로 경매사 또는 감별사의 경험이나 표본검사에 의존하고 있다. 최근 과실류에 비해 크고 껍질이 두꺼운 수박, 메론 등의 내부품질을 비파괴ㆍ실시간으로 판정하기 위한 연구가 국내외에서 활발히 수행중이다. 특히 X-선, 음파, 근적외선 등을 이용하여 숙도, 공동, 당도, 밀도 등을 신속히 검출하기 위한 연구가 대부분을 차지하고 있다. (중략)

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.129-138
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• 2008

The characteristics of beneficiating kaolin mineral by liberation (selective grinding) and air classification have been investigated, comparing the grinding rates of ball mill and impact mill. The ore was ground using a ball mill and a impact mill to evaluate the grindability of the two grinding methods based on the constant production amount of fine particles in size less than 325 mesh. Then, the fine product was further separated into two fractions using an air-classifier and each fraction was chemically analyzed to compare the beneficiation efficiency of the two grinding methods. The chemical grade of kaolin mineral decreased as increasing the grinding rate of both the mills. particularly in the case of ball mill because of overgrinding impurities such as quartz and feldspar. In the case of the ball milling, the fine fraction less than 325 mesh was air-classified at a cutting point of $43\;{\mu}m$. The production rate of the air-classified concentrate was found to be 66.2 wt%, removing 5.3% of $Fe_2O_3$ and 34.6% of CaO. Under the same conditions mentioned above with the impact mill, the production rate of the air-classified concentrate was 64.4 wt%, removing 34.2% of $Fe_2O_3$, 67.6% of CaO and 25.0% of $TiO_2$. Therefore, our results indicate that impact mill is superior to ball mill in terms of impurity removal.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.123-134
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• 1999

The electrical properties such as dielectric constant, dielectric loss factor and AC conductivity of grain were presented to measure the moisture content of grain using RF impedance. At frequency ranging from 1 to 10MHz and room temperature, $20^{\circ}C$, vector network analyzer(HP4195) and coaxial type sample holder were used to analyze the electrical properties of paddy(11∼24%w.b.), brown rice(11∼18%w.b.), barley(11∼21%w.b.) and wheat(11∼23%w.b.) depending on the moisture content, frequency and bulk density. The dielectric constant and AC conductivity of grain samples increased with moisture content and bulk density. The dielectric constants decreased with frequency and could be expressed as function of the moisture density(decimal moisture $content{\times}bulk$ density).

• Journal of Biosystems Engineering
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• v.23 no.6
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• pp.583-590
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• 1998

This study was performed to determine the kinetic friction coefficient bulk density, dynamic and static angle of repose, and terminal velocity of the chopped rice straw in the moisture range of 8~23%, which could be used for 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 the mass of rice straw on the various plate materials. Bulk density was measured with an apparatus consisting of a filling funnel and a receiving vessel. 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 the cylindrical container after natural discharge of the bulk sample through a circular hole in the bottom plate. Kinetic friction coefficients of rice straw on the PVC, mild steel, stainless steel, and galvanized steel were in the range of 0.303~0.434, 0.222~0.439, 0.204~0.448, and 0.206~0.407, respectively. and indicated linear increase with moisture content. The effects of moisture change on the friction coefficients were in the order of PVC, mild steel, galvanized steel, and stainless steel. Bulk density, dynamic and static angle of repose, and terminal velocity were in the range of 56.8~60.3 kg/m$^3$, 41.4~45.9$^{\circ}$, 94.4~100.8$^{\circ}$, and 1.07~4.48 m/s, respectively, and were increased linearly with the moisture content.

• Journal of Biosystems Engineering
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• v.20 no.2
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• pp.141-150
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• 1995

땅콩을 대상으로 하는 각종 농산가공기계의 개발 및 최적 작동에 필요한 땅콩 자실의 물리적, 기계적 및 공기 역학적 성질에 대한 연구가 수행되었다. 영호, 올, P.I. 314817의 3 가지 품종에 대해 땅콩 자실의 형상, 각부 칫수, 진밀도, 산물밀도 및 종실율이 측정되었으며, 땅콩자실에 대해 압축실험을 실시함으로써 자실이 파괴될 때의 힘, 변형량, 그리고 단위 체적당 최대 흡수 에너지인 터프니스 계수를 측정하여 기계적 성질로서 제시하였다. 공기 역학적 성질로서는 땅콩 자실과 종실의 종말속도 및 항력계수가 측정되었다. 1. 땅콩 자실의 기하학적 형상은 수원체로 모형화할 수 있었다. 2. 진밀도는 땅콩 자실의 경우는 515-620 $kg/m^3$, 종실의 경우는 960-1,090 $kg/m^3$, 의 값을 보였다. 3. 대합면이 수평인 자세에서의 파괴력은 영호가 61.9 N, P.I. 314817은 71.5 N, 올 땅콩은 84.8 N였으며, 터프니스 계수는 각각 30, 43, 72 kN-$m/m^3$, 의 값을 보였다. 모든 품종과 함수율에서 파괴력과 터프니스 계수는 대합면이 수직인 자세에서보다 수평자세에서 더 큰 값들을 보였다. 4. 땅콩 자실과 종실의 평균 종말속도는 각각 8.7-9.9 m/s, 10.0-11.6 m/s 범위였다. 종말속도는 진밀도와 직선적인 관계가 있었으며 품종과 형상에 따른 뚜렷한 종말속도의 차이는 보이지 않았다.