• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.229-238
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• 2013

This study was conducted to analyze on the operational cost of logging operations in the whole-tree logging operation system by tower-yarder and swing-yarder, and in the cut-to-length logging operation system by excavator with grapple in order to spread efficient logging operation technique and to establish the logging operation system. In the results of the analysis of operation cost, in case of the whole-tree logging operation system, the operation cost was 2,099 won/$m^3$ in felling by chain saw, 28,286 won/$m^3$ in yarding by tower-yarder, 18,265 won/$m^3$ in yarding by swing-yarder, 18,939 won/$m^3$ in bucking by excavator with grapple and chain saw, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle. In case of the cut-to-length logging operation system, the operation cost was 10,160 won/$m^3$ in felling and bucking by chain saw, 7,567 won/$m^3$ in cut-to-length extraction by excavator with grapple, 6,982 won/$m^3$ in branches and leaves extraction by excavator with grapple, 3,040 won/$m^3$ in the operation road construction by excavator with grapple, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.170-177
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• 2000

Sorting cut roses according to quality is very essential to increase the value of the product. Many factors are involved in determining the grade of cut roses: length, thickness, and straightness of stem, color and maturity of bud, and extra. Among these factors, the stem straightness and bud maturity are considered to be difficult to set proper classification criteria. In this study, a prototype machine and an analysis procedure were developed to grade cut roses according to stem straightness and bud maturity by utilizing color image processing and neural network. The test results indicated 15.8% classification error for stem straightness and 10.0% for bud maturity.

• Journal of Biosystems Engineering
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• v.34 no.4
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• pp.228-233
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• 2009

In order to cut the round bale easily, a roughage cut-feeder for the round bale was developed in this study. This study consists of two parts. One is development of a cutting mechanism and a performance test reported in the previous paper. This is the second part of the study. For the study, recent trend of traditional cutting system was analyzed. Also, cost of the prototype cut-feeder was analyzed and determine the break-even point of farm size was determined by comparing with traditional method using a traditional cutter. A prototype cut-feeder was investigated with the fact that working performance, fiber length and shape of roughage and feeding quality was good. Operating cost of the prototype cut-feeder decreased rapidly with an increase of farm size. Break-even point in terms of farm size was 36 heads for beef and 28 heads for dairy. Also, costs estimated were 118,000 won/head year and 148,000 won/head year, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.3
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• pp.155-161
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• 2021

This study was conducted to estimate the effect of different cutting lengths on fermentation characteristics and aerobic stability of whole crop rice (WCR) silage. The WCR was harvested at the yellow ripe stage (43.7%, DM), and then cut at 5 (R05), 10 (R10), and 20 cm (R20) of the theoretical length of cut with no cut WCR (R60). Each forage was ensiled into 20 L mini bucket silo (5 kg) for 150 days in quadruplicates. The cutting lengths were not affected the chemical compositions of WCR silage (p > 0.05). The pH (p < 0.001) and concentration of ammonia-N (p = 0.022) in WCR silage were increased linearly with the increase of cutting length. The concentration of lactate had quadratic effect (p = 0.007), which was highest in R20 silage (p < 0.05). The concentration of acetate was increased linearly (p = 0.014), but the concentration of butyrate was decreased linearly (p = 0.033). The lactic acid bacteria count was decreased linearly (p = 0.017), and yeast count had quadratic effect (p = 0.009), which was the highest in R20 silage (p < 0.05). Aerobic stability had strong quadratic effect (p < 0.001), which was the highest in R20 silage (p < 0.05). In conclusion, R60 silage had highest pH by a linear increase of ammonia-N concentration and led to low aerobic stability. While R20 silage had the lowest pH by high lactate concentration and led to high aerobic stability.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11b
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• pp.258-268
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• 2005

A new approach has been adopted to remove the hot particulates from nuclear facilities, KAERI, South Korea, by using the new compact cyclone train, made of steel ness steel, with optional vortex finder length. Flow rate results showed a dramatic change in removal efficiency, performance was changed with the change of exit tube length. The 15 m/s flow rate was found suitable one for new equipment with the 49 mm optimum exit tube length for 76 mm cyclone body diameter. Results shows the removal efficiency for $1\;{\mu}m$ was more than $65\%$ and for $10\;{\mu}m$ was seen ${\~}97\%$. Over 15 m/s flow rate, was not shown much different in removal efficiency. The removal efficiency increased with the flow rate, and pressure drop. Cut size diameter decrease with the inlet flow rate. Cut size diameter found lowest with 49 mm exit tube length and 15 m/s flow rate. For filters the performance decreased with the inlet velocity increased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.36-41
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• 2013

One of the problems in grinding process using a machining center(MC) with a small diametric wheels is machining error due to decrease of the quill diameter. In this study, side-cut grinding is performed with a vitrified bonded CBN wheel on the machining center. Grinding experiments are performed at various grinding conditions including quill length, quill diameter and depth of cut. The effect on the grinding force, machining error and surface roughness due to the change of the quill rigidity are investigated experimentally. The slenderness ratio of the quill is significant factor to analyse the change of the grinding force and machining error.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.264-268
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• 1986

A thchnique has been studied for the measurement of the spectral loss and the cut-off wave length, at which the first high-order mode disappears. The near-field patterns of a fiber which is excited by a variable wavelength source are used for the measurement of cut-off wavelength. Because of the absorptive phenomenon of OH- molecular vibration, spectral loss of a single mode optical fiber sample is 5.6dB/km at 1380 nm wavelength and 1dB/km at 1240 nm wavelength. From the near field intensity patterns and the mode field diameter graph for the half power width, the cut-off wavelength of the fiber is measured to be 1120 nm.

• ALGAE
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• v.36 no.4
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• pp.327-332
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• 2021

Raw material of gelidioid red algae yielding high-quality agar has been in short supply due to overharvesting, but in situ farming of gelidioids has not been practical due to their slow growth. To produce vegetative seedstock of a cosmopolitan species, Pterocladiella capillacea, we investigated the number and length of regenerated branches arising from sectioned fragments during 3 weeks of laboratory culture at 10, 15, 20, and 25℃. All sectioned fragments formed axis-like branches mostly from the upper cut edge and stolon-like branches mostly from the lower cut edge, showing a high capacity of regeneration and intrinsic bipolarity. At 20℃, the number of regenerated branches increased to 2.74 ± 1.29 on the upper cut edge and 4.26 ± 2.66 on the lower cut edge. Our study reveals that the use of fragments bearing regenerated branches as seedstock can be a simple method to initiate fast propagation for mass cultivation in the sea or outdoor tank.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.9
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• pp.1139-1147
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• 2000

This paper describes that the size of inactive zone can be directly applied to design multiblade fan/scroll system. From the experimental studies using a five hole pitot tube and smoke test, it is found that the size of inactive zone has linear relations with the mean velocity of impeller inlet and cut-off angle gives a great influences to the fan efficiency. For the practical design, a function related with geometric parameters(i.e. inner radius, cord length, cut-off clearance and cut-off angle) of fan/scroll system is suggested. By using these formulas, the size and distribution of inactive zone can be predicted without the measurements through the full domain, it can be possible to use them to know the efficiency improvement for new model designed.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.87-93
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• 2014

PURPOSES : To evaluate the feasibility of cut waste fishing net as a reinforced fiber for concrete. METHODS : Strength characteristics of fiber reinforced concrete using waste fishing net were investigated. The cut waste fishing nets with 4~5cm length were putted into the soil-cement and cement concrete for pavement slab. RESULTS : Compression and tensile strength of fiber reinforced concrete using waste fishing net were increased. CONCLUSIONS : It was concluded that cut waste fishing net can be used as a reinforced fiber for cement concrete. However, sometimes using cut waste fishing net leads to decrease the strength; therefore, further researches are needed for real project.