• Tribology and Lubricants
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• v.11 no.3
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• pp.40-47
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• 1995

The engine oil life was examined experimentally for small size single cylinder engines. This study was conducted in the laboratory. An Eddy Current type engine dynamometer was used with a motorcycle and a cultivator engine. Physical and chemical properties of used oil was analyzed to examine the oil life. Flushed oil was used for the reference instead of the new oil. It were found that deterioration of dynamic viscosity and anti-wear property of engine oil was due to dilution by fuel not depletion of ZDTP.

• Microbiology and Biotechnology Letters
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• v.21 no.6
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• pp.520-526
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• 1993

A morphologically different form of Ganoderma lucidum was isolated from a cultivator's farm, and its optimum growth conditions were determined. A major difference in their morphology was color of fruit bodies. Fruit bodies of the mutant were white wherase those of normal Ganoderma lucidum were red. Spores of the mutant were global and mycelia were thin. Mycelial growth of this white mutant was favorable on potato sucrose agar medium, and optimum pH of the medium was 5.5.

• Journal of Biosystems Engineering
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• v.29 no.5 s.106
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• pp.385-394
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• 2004

The objectives of this study were to investigate the effectiveness of rubber as an engine mount of walking-type cultivators and to determine its optimal spring constant and damping coefficient using a dynamic simulation of the engine mount system. Four different types of rubber mounts were tested to determine their spring constants and damping coefficients, and the best type was selected for the isolation of the engine vibrations transmitted to the handle. The total vibration levels transmitted to the handle when the rubber mounts weren't installed were 17.52 $m/s^2$. The total vibration levels transmitted to the handle when the rubber mounts were installed were 10.69 $m/s^2$ for Stripe 1, 11.33$m/s^2$ for Stripe 2, 10.92$m/s^2$ for Stripe 3 and 14.19$m/s^2$ for Hive, respectively, resulting in an average of $30\%$ reduction when compared with that without the engine mount. A dynamic model of the cultivator's engine-mount system and its simulation program were developed and verified. A method was proposed to determine the optimal spring constant and damping coefficient of the engine-mount system. It was found from the simulation that a spring constant of 4,100 kN/m and the largest damping coefficient were the most effective for the vibration isolation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.446-459
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• 2000

This study was carried out in order to find out an effective machinery utilization strategy by conducting a survey on utilization and maintenance of agricultural machinery. The survey showed that the no. of utilization hours for power tiller in a year was 190.2hrs, 208.6hrs for tractor, 59.1hrs for rice transplanter, 74.0 hrs for combine, 44.6 cultivator and 254.4hrs for 4.4hrs for grain dryer. The period covered the time the machine was until it became unserviceable. The results are as follows: 10.0yrs for power tiller, 7.5yrs for tractor, 7.4yrs for rice transplanter and 5.4yrs for combine. This indicate that the actual period of use for power tiller and rice transplanter was longer than the expected period of duration years so there is a need for adjustment. The factors considered by the farmers for purchasing agricultural machine were: farm size(32%), machine operation (26.0%), performance(l4.0%) and post or after sales service(12.6%), according to the survey. It showed that repair cost rate in a year was classified into major agricultural machine; 4.8% for combine; 3.9% for tractor; 3.5% for rice transplanter; 2.0% for power tiller; 1.6% for grain dryer; and 1.2% for cultivator. The reasons for poor maintenance were insufficient after sales service(25%) and difficulty in buying parts(75%) because of the unavailability of parts in local shops(55%), imported models(30%) and outmoded model(15%).

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.154-161
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• 2000

A series of soil bin experiment was carried to investigate the effects of rotary blade shape, rotational direction of rotary blade, number of blade and soil cutting disk blade on the characteristics of partial tillage. Among the three types of rotary blades, rotary blade for cultivator was considered to be proper for partial tillage of direct seeder considering the torque requirements and ratio of soil breaking. There is no need to attach so many blades to the rotary shaft. Four rotary blades were enough for efficient partial tillage by rotary tiller. Though soil cutting disk blade assisted the better formation of seedbed furrow, attachment of the soil cutting disk blade increased torque requirements.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.87-92
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• 2019

In this paper, a closed hydroponics device was designed and fabricated to grow and harvest plants in a small space for safe consumption, which enables horticultural activities that are difficult to perform due to space constraints from urbanization. This device also aimed to minimize the air pollution of crops. To obtain data for the optimal growth conditions for crops in this intelligent plant-growing system, sensors were used to measure and control the growth conditions. To investigate the optimal growth conditions, blue lettuce and crown daisy were selected as representative crops. The growth rates were comparatively analyzed through four experiments for each plant. This hydroponics device was used to collect data on growth rates that are altered depending on cultivation conditions, which can then be used to study methods to control the growth rate of crops.

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.121-128
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• 1999

This experiment was carried out to establish effective weed control system in the cultivation of Coix lachryma-jobi L. The effect of annual weeds artificially transplanted on the growth of Coix lachryma-jobi L. were that the higher the density of weeds, the lower the yield considerably by reducing number of grains and tillers per plant. Among four weeds of Echinochloa crusgalli galli P. BEAUV., Digitaria sanguinalis $S_{COPOL}$., Chenopodium album L., and Portulaca oleracea L., weed of Portulaca oleracea L. reduced adlay yield most by 182.6kg/10a and it was judged to be the most injurious weed to adlay production. Among four weed control systems, which are one herbicide treatment, one herbicide treatment + one cultivating work with cultivator, two times cultivating work with cultivator and two times hand-weeding, the control system of 'one herbicide treatment + one cultivating work with cultivator' showed the lowest amount of weed growth by 7.34 weeds per $m^2$ in comparison with control plot of 35.00 weeds per $m^2$. Among four weed control systems, the system of 'two times hand-weeding' had much more amount of light penetration in adlay canopy with 791.9 mol than any other systems.

• Journal of Trauma and Injury
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• v.19 no.2
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• pp.97-104
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• 2006

Purpose: Many factors influence the occurrence and severity of geriatric trauma, and regional weather is regarded as one factor that influences geriatric trauma. In this study, to predict the type, severity, and incidence of geriatric trauma patient, we analyzed the influence of regional weather on geriatric trauma. Methods: The subjects of our investigation were trauma patients over sixty-five years of age who visited the Emergency Department (ED) of Yeungnam University Hospital during a one-year period. We retrospectively reviewed the medical charts of 436 geriatric trauma patients, and the data were analyzed by using SPSS 12.0 for Window. The weather was based on data from the Korea Meteorological Administration. Results: The average age was 72.8 years old, and the ratio of males to females was 1:1.1. The mean spell out ISS was 10.8, and no difference was found between males and females. Slips were the most common cause of trauma. The largest numbers of aged trauma patients, 46, visited the ED in May, and the smallest number of such patients, 24, visited the ED in December. In addition to, summer saw the largest number of aged trauma patients. The type of trauma, the Injury Severity Score, and the number of patients had no relationship with season. On sunny days, the ISS was larger in patients who had hypotension and who had tachycardia. On rainy day, the ISS was larger in male patients and cultivator accident patients. The number of patients was larger on partly cloudy days. Conclusion: In spring and summer and on partly cloudy days, we must be prepared to treat aged traumatized patients in the E.D. On rainy days, visual sensation, tactual sense, and acoustic sense must be closely examined. In addition,on rainy day, aged male traumatized patients or cultivator accident patients must to be closely observation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.307-307
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• 2017

There is a growing need to understand how local, farm household, and elementary units are responding to changes in agricultural conditions due to increased internal and external agrarian conditions and increased uncertainty in agricultural management due to increasing FTA and climate change. Therefore, we analyze dynamics of changes through more detailed and precise gathering of information related to agricultural products and DB, and by analyzing the satisfaction level of the first year panel survey by constructing a producer panel for utilization in agricultural research and policy. A total of 500 farmers in the producer panel who mainly grow rice, garlic, onion, strawberry, apple were collected through questionnaires. The actual analysis used data from a total of 393 farm households, including 82 farms of rice, 51 farms of apple, 100 farms of garlic, 88 farms of onion and 72 farmhouses of strawberry. The distribution by age was similar to the distribution of rural ages in Korea, with 2.8% under 30s, 17.6% in 40s, 32.4% in 50s, 37.5% in 60s and 9.7% in 70s. Panel happiness and rural life satisfaction were examined using the 7 - point Likert scale and the analysis method was one - way ANOVA. The results showed that the happiness of garlic and strawberry cultivator was significantly higher than that of rice and onion cultivator. However, the satisfaction of rural life did not show any difference among the cultivars. As a result of difference verification about Agricultural Outlook and Crop-specific Outlook after 5 years, there was no difference between the crops in terms of prospects for Korean agriculture after five years, but a survey of industrial prospects for crops after five years showed that the rice growers have a significantly negative outlook compared to garlic, onion and strawberry growers, and garlic and onion growers have a more positive outlook than rice and apple growers As a result of verifying whether there is a difference in ages between the agricultural prospects and the industrial prospects by crops after 5 years, there was no difference between the ages of prospects for Korean agriculture after 5 years, However, in the survey on industrial prospects by crops after 5 years, 40s were more positive than 60s.

• Korean Journal of Agricultural Science
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• v.34 no.2
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• pp.189-200
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• 2007

The purpose of this study is to evaluate the farmland scale improvement project and to present basic data for establishing a long-term improvement scheme of this project. Professional rice cultivators' farming scale after receiving the farmland scale improvement fund has increased compared to the situation before receiving the fund support. The average paddy fields increased by 220% (from 2.75ha to 8.82ha), the average upland increased by 27% (from 0.44ha to 0.56ha), and the average orchard land increased by 44% (from 0.25ha to 0.36ha). The rice production costs per 10a are estimated as 608,678won for below 3ha, 488,721won for 3-6ha, 487,431won for 6~10ha, and 425,313won for over 10ha, which decreased with increasing farming scale. The effects of the farmland scale improvement project on income variation are summarized as follows. 1) Average farm household income for all subjects has increased by 223 % (from 40,517,000won to 90,295,000won). 2) For each category, the results show that average farm household income has increased by 9,766,000won for below 3ha, 35,898,000won for 3~6ha, 42,822,000won for 6~10ha, and 72,697,000won for over 10ha.