• Korean Journal of Agricultural Science
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• v.40 no.1
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• pp.53-59
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• 2013

Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.29-36
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• 2012

This study was carried out to investigate the runoff characteristics in paddy field using livestock compost fertilizer. Irrigation, runoff and water quality data in the paddy field were analyzed periodically from May to September in 2011. The observed amounts of rainfall, irrigation, runoff for the experimental paddy field during the irrigation period were 1,148.2 mm, 523.9 mm, and 344.7 mm, respectively. T-N concentrations ranged from 2.28 mg/L to 11.75 mg/L, which was generally higher than the quality standard of agricultural water (1.0 mg/L). T-P concentrations ranged from 0.018 mg/L to 0.241 mg/L and the average was 0.122 mg/L. The runoff loads of T-N and T-P were 15.7 kg/ha and 0.4 kg/ha, respectively. The runoff pollutants loadings in T-N and T-P in this study were much lower values than the loads of T-N and T-P from the paddy field presented by others' studies. We are considering that these results were affected by rainfall as well as hydrological condition, irrigation water, fertilizer application, rice straw and plowing.

• KCID journal
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• v.18 no.1
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• pp.94-102
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• 2011

The aim of this study was to evaluate the load of non-point sources pollutant at a paddy plot located at the valley watershed during irrigation period. Irrigation, runoff and water quality data in the paddy plot were analyzed periodically from June 1 to October 31 in 2005. The observed amount of precipitation, irrigation, runoff for the experimental paddy plot during the irrigation period was 1,297.8, 223.2, and 825.4mm, respectively. Total-N concentrations ranged from 3.73 to 18.10mg/L, which was generally higher than the quality standard of agricultural water (1.0mg/L). Total-P concentrations ranged from 0.111 to 0.243mg/L and the average was 0.139mg/L. The observed runoff pollutants loadings from the paddy plot were measured as 34.4 kg/ha for T-N, 1.0 kg/ha for T-P and 213.8 kg/ha for SS. The non-point sources pollutant load in drainage water depends on rainfall and surface drainage water amount from the paddy plot. We are considering that these results were affected by rainfall as well as hydrological condition, soil management, whether or not fertilizer application, cropping, rice straw and plowing.

• Tribology and Lubricants
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• v.34 no.6
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• pp.318-324
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• 2018

This study aims to visualize the friction and wear behaviors of metal coatings in real time. The main mechanism of wear is identified by observing all the processes in which wear occurs. The friction coefficients of the moments are monitored to confirm the relationship between the friction and wear characteristics of the coating. Thin Ag coatings, which are several hundred nanometers in thickness, are prepared by depositing Ag atoms on silicon substrates through a sputtering method. A pin-on-disk-type tribo-tester is installed inside a scanning electron microscope (SEM) to evaluate the friction and wear characteristics of the Ag coating. A fine diamond pin is brought into contact with the Ag coating surface, and a load of 20 mN is applied. The contact pressure is calculated to be approximately 15 GPa. The moments of wear caused by the sliding motion are visualized, and the changes in the friction characteristics according to each step of wear generation are monitored. The Ag coating can be confirmed to exhibit a wear phenomenon by gradually peeling off the surface of the coating on observing the friction and wear characteristics of the coating in real time inside the SEM. This can be explained by a typical plowing-type wear mechanism.

• Tribology and Lubricants
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• v.21 no.5
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• pp.209-215
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• 2005

Nano/micro friction with the contact area was studied on Si-wafer (100) and diamond-like carbon (DLC) film. Borosilicate balls of radii $0.32{\mu}m,\;0.5{\mu}m,\;1.25{\mu}m\;and\;2.5{\mu}m$ mounted on the top of AFM tip (NPS) were used for nano-scale contact and Soda Lime glass balls of radii 0.25mm, 0.5mm, 1mm were used for micro-scale contact. At nano-scale, the friction between ball and surface was measured with the applied normal load using an atomic force microscope (AFM), and at micro scale it was measured using ball-on flat type micro-tribotester. All the experiments were conducted at controlled conditions of temperature $(24\pm1^{\circ}C)$ and humidity $(45\pm5\%)$. Friction was measured as a function of applied normal load in the range of 0-160nN at nano scale and in the range of $1000{\mu}N,\; 1500{\mu}N,\;3000{\mu}N\;and\;4800{\mu}N$ at micro scale. Results showed that the friction at nano scale increased with the applied normal load and ball size for both kinds of samples. Similar behavior of friction with the applied normal load and ball size was observed for Si-wafer at micro scale. However, for DLC friction decreased with the ball size. This difference of in behavior of friction in DLC nano- and microscale was attribute to the difference in the operating mechanisms. The evidence of the operating mechanisms at micro-scale were observed using scanning electron microscope (SEM). At micro-scale, solid-solid adhesion was dominant in Silicon-wafer, while plowing in DLC. Contrary to the nano scale that shows almost a wear-less situation, wear was prominent at micro-scale. At nano- and micro-scale, effect of contact area on the friction was discussed with the different applied normal load and ball size.

• Journal of Biosystems Engineering
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• v.15 no.1
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• pp.52-60
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• 1990

The main purpose of this report is to analyse the utilization results of farm machinery, farm mechanization rate and influences on the farm household economy. These results are summarized as follows : 1) The annual working days of major farm machinery are from 34.3 to 68.8 days for power tillers and tractors ; 7.9 to 8.5 days for rice transplanters ; 3.6 to 6.9 days for binders ; and, from 18.6 to 20.6 days for combines. Also income and expenditures of the farm management reveals al surplus in major farm machinery except for binders. 2) The popularization rate of major farm machinery is currently low, reaching the level of the early 1970's in Japan and the level of the early 1980's in Taiwan for rice transplanters and harvesters respectively. 3) The farm mechanization rate is 81.7% in plowing & levelling, 66.3% in rice transplanting, 87.5% in pest and disease control, 62.1% in harvesting and 12.5% in drying. However the farm mechanization rate of rice transplanting, harvesting and drying still remains at a low level. 4) The composition rates of farm machinery and implements are 10.2% in farm management expenditures (23.6% in Japan) and 13.2% in fixed capitals (29.4% in Japan) which still reflect a low level, and below that of the 1970's in Japan. From these analysis results, farm mechanization contributes to the improvement of farm management. Nevertheless, the popularization status and mechanization rate are still at a low level in korea. Therefore, it is deemed desirable to furthure promote effective utilization methods and guide farmers in higher safety utilization and management technology.

• Journal of the Korean Dietetic Association
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• v.16 no.1
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• pp.49-61
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• 2010

The purpose of this study was to determine basic information on the microbiological quality of environmentally friendly vegetables used in school foodservices. Comparisons were made on the microbiological quality of eight different kinds of vegetables grown by environmentally friendly agricultural methods and ordinary agricultural methods to determine if there were significant differences. In the raw materials, aerobic plate counts were as follows: lettuce 4.58~7.43 log CFU/g, winter plowing chinese cabbage 5.61~7.36 log CFU/g, Korean leek 5.81 log CFU/g to TNTC (too numerous to Count), cabbage 5.93~6.43 log CFU/g, sesame leaves 3.15~5.23 log CFU/g, cucumber 5.00~5.79 log CFU/g, cherry tomato 2.96~5.40 log CFU/g, paprika 1.30~3.52 log CFU/g. In the comparison of the microbiological quality between environmentally friendly and ordinary agricultural vegetables, their acceptable ratio was the same (81.3%) and the mean aerobic plate counts was not significantly different. In the comparison of the microbiological quality between the leafy vegetables and the fruity vegetables, the fruity vegetables had a 100% acceptable ratio regardless of the agricultural method used to grow them, while the leafy vegetables had an acceptable ratio of 70%. In terms of the aerobic plate counts, the leafy vegetables had significantly higher counts; the leafy vegetables 5.87${\pm}$1.18 log CFU/g, the fruity vegetables 4.12${\pm}$1.54 log CFU/g.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.273-280
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• 2001

We investigated the flora and vegetation structure of exotic plants along stream geomorphology and disturbance factors in the riparian zone of Seunggi stream, Incheon. Total 53 exotic plant species were found in the riparian corridors of Seunggi stream. The percentage of exotics ranged from 25% to 33% of total species richness, and its mean value was 24% in the whole riparian area. The percentage of exotics reflected the vulnerability of riparian zones to plant invasions by disturbances, and it could be used as an indicator of riparian system dysfunction. The distinct distribution patterns of exotic plants did not found in the lateral topographic features of the stream. Invasion and proliferation of the exotic plants were somewhat remarkable at terraces and bank slopes of the stream. Among various disturbance factors, plowing and trampling were important on the invasion of exotic plant species of Seunggi stream.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.140-147
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• 1999

Since the national land area is small and the fanning land occupies only 24% of total land area in Korea, the promotion of agricultural productivity is urgent. In this process, the application rate of chemical fertilizer, which is the major pollution factor at agricultural non-point sources, has been increasing in every year. The present study examined difference of runoff loading of nitrogen and phosphorus by rainfall intensity(above 100mm, 80-100mm, 50-80mm and 30-50mm). Runoff loading of nitrogen and phosphorus by rainfall intensity has differences under similar rainfall intensity. We are considering that these results were affected by rainfall intensity as well as hydrological condition, soil management, whether or not fertilizer application, cropping, rice straw and plowing.

• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.15-20
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• 2010

Tractor PTO output and fuel consumption rate under the korean paddy and various paddy operations were measured and analyzed, in which all the measurements were accomplished by the OECD tractor test codes and the collected information will be utilized for defining tractor energy efficiency class and its test methods. Tractor PTO performance tests were conducted under full-load, part-load and various engine RPMs with part-load at the engine laboratory, while the paddy operations were dry land plowing, wet and dry land rotary tilling and wet land preparation under various soils. As a whole, the rated tractor outputs were ranged from 17% to 100% in the various tillage and land preparation operations, however, the loads for the paddy operations of 1,700 to 2,000 rpm were very close to the OECD tractor load distribution thus it would be appropriate to adopt OECD tractor test codes to measure energy consumption efficiency of tractor.