• Journal of the Korean Society of Safety
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• v.9 no.4
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• pp.17-28
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• 1994

Chip breaking is important in lathe work for maintaining good surface of the products and safety of operator. The purpose of this study is to investigate the performance of chip breaking and chip shape resulted from the carbide inserts with grooved type and obstruction type chip breaker. Experiments have been performed under the following cutting conditions, (1) constant cutting speed with variable depth of cut and feed rate, (2) constant depth of cut with variable cutting speed and feed rate. Also, the flying distance of chip and it's distribution have been investigated. As a results, good performance of chip breaking can be obtained for small radius of curvature and land width of grooved type chip breaker. And the thickness of chip increase with the increase of feed rate and decrease of cutting speed, and the chip breaking becomes easier with the increase of chip thickness due to the large deformation rate. Obstraction type chip breaker shows better performance of surface roughness than the grooved type. The flying distance of the chips over 90% are less than 1 meter, and the distance decreases as the feed rate decreases.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.6
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• pp.903-910
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• 2015

To maintain a predominantly pasture-based system, the large herd milked by automatic milking rotary would be required to walk significant distances. Walking distances of greater than 1-km are associated with an increased incidence of undesirably long milking intervals and reduced milk yield. Complementary forages can be incorporated into pasture-based systems to lift total home grown feed in a given area, thus potentially 'concentrating' feed closer to the dairy. The aim of this modelling study was to investigate the total land area required and associated walking distance for large automatic milking system (AMS) herds when incorporating complementary forage rotations (CFR) into the system. Thirty-six scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as moderate; optimum pasture utilisation of 19.7 t DM/ha, termed as high) and 6 rates of replacement of each of these pastures by grazeable CFR (0%, 10%, 20%, 30%, 40%, 50%) were investigated. Results showed that AMS cows were required to walk greater than 1-km when the farm area was greater than 86 ha. Insufficient pasture could be produced within a 1 km distance (i.e. 86 ha land) with home-grown feed (HGF) providing 43%, 29%, and 22% of the metabolisable energy (ME) required by 400, 600, and 800 cows, respectively from pastures. Introduction of pasture (moderate): CFR in AMS at a ratio of 80:20 can feed a 400 cow AMS herd, and can supply 42% and 31% of the ME requirements for 600 and 800 cows, respectively with pasture (moderate): CFR at 50:50 levels. In contrast to moderate pasture, 400 cows can be managed on high pasture utilisation (provided 57% of the total ME requirements). However, similar to the scenarios conducted with moderate pasture, there was insufficient feed produced within 1-km distance of the dairy for 600 or 800 cows. An 800 cow herd required 140 and 130 ha on moderate and high pasture-based AMS system, respectively with the introduction of pasture: CFR at a ratio of 50:50. Given the impact of increasing land area past 86 ha on walking distance, cow numbers could be increased by purchasing feed from off the milking platform and/or using the land outside 1-km distance for conserved feed. However, this warrants further investigations into risk analyses of different management options including development of an innovative system to manage large herds in an AMS farming system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.85-91
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• 2013

The machinability of wear-resistible tungsten carbides and the tool wear behavior in machining of V30 and V50 tungsten carbides using PCD (Poly Crystalline Diamond) cutting tool was investigated to understand machining characteristics. This material is one of the difficult-to-cut materials in present, but their usage has been already broadened to every commercial applications such as mining tools, and impact resistant tools etc. Summary of the results are as follows. (1) Tool wear progression of PCD tools in turning of wear-resistible tungsten carbides were observed specially fast in primary cutting distance within 10m. (2) Three components of cutting resistance in this research were different in balance from the ordinary cutting such as that cutting of steel or cast iron. Those were expressed large value by order of thrust force, principal force, feed force. (3) If presume from viewpoint of high efficient cutting within this research, a proper cutting speed was 15m/min and a proper feed rate was 0.1mm/rev. In this case, it was found that the tool life of PCD tool was cutting distance until 230m approximately. (4) In cutting of wear-resistible tungsten carbides such as V30 and V50, it was recognized that the tool wear rate of V30 was very fast as compared with V50. (5) When the depth of cut was 0.1mm, there was no influence of the feed rate on the feed force. And the feed force tended to decrease as the cutting distance was long, because the tool was worn and the tool edge retreated. (6) It was observed that the tungsten carbides were adhered to the flank.

• Journal of Welding and Joining
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• v.4 no.3
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• pp.50-57
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• 1986

In this study, the experiments were earried out for the purpose of the clarifying the optimum metal arc spraying conditions, such as spraying distance, wire feed speed, arc current, etc, by using the stainless steel wire ER 308L. Main results obtained are as follows: 1. Optimum spraying distance is closely related to the equilibrium temperature of base material in back surface. 2. The size fused metal particles is increased according to the temperature of fused metal. 3. The maximum adhesion strength of coatings is obtained under the optimum spraying conditions of which the temperature of fundamental is maximum.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.5-13
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• 2003

The soil nailing is one of the useful support-system in urban excavation because of the presence of other structures in the vicinity Since the soil nailing system was introduced, model experiments and theoretical studies have been performed to investigate behavior of soil nailed wall. However, there are few data in the case of multi-layered soil strata just like Seoul Metropolitan area in Korea. The feed back analyses are carried out using the measured wall displacement data for soil nailing construction sites with multi-layered strata in order to analyze the distance and the coefficients of extension zone of ground behind soil nailed wall. As a result, the distance of extension zone increased with increasing of the final excavation depth and the ratio of the distance to the final excavation depth was shown to be about 94% of the final excavation depth. Also, the coefficients of extension zone increased with enlargement of soil layer thickness and converged into constant value of 1.05. On the other hand, the maximum vertical displacements by the feed back analysis and Caspe's method were shown to be approximately 80%, 150~280% of the maximum horizontal displacement respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.4
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• pp.234-239
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• 2006

This paper introduces an auto-feeding system to exactly control the feeding time and the amount to cultured fishes in aquaculture industrial field. To reduce expensive costs or labors in this field, it was designed by the concept of controlling feed quantity exactly on the basis of fish's feeding behavior pattern in water tank. A feed control method of this system was developed for controlling feed amount by rotor capacity and motor rotated number. Moreover, a scattering section was selected by rotate way of propeller wing to scatter dried feed to designated site, and then, the diameter of its wing was 250mm and maximum scattering distance was 7.6m for 600rpm. Furthermore, the scattering ways were embodied 2 types such as a simplified way and a multistage shift way looks like a manual scattering. As a results, the multistage shift way is more effective to discharge the dried feed widely than the simple way in the water tank.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1390-1392
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• 2000

In this paper, a numerical calculation method based on CSM has been described. The electric field must be nonuniform even close to railway feed system. In that case, to calculate induced voltage, this paper uses the mutual capacitances between a conductor and railway feed system. The induced voltages of a conductor located at point (height=4m, distance=8m) near by railway feed system are calculated from 370V to 668V.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.15-28
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• 1998

Recently may investigations have been studied on the high-speed machining by using machine tools. A CNC machine tool makes some tool path errors caused by software acceleration/deceleration. The faster a cutting feedrate is, the bigger the tool path errors are. Some known methods reduce these kinds of errors, but they make the total cutting time increased. This paper presents a feed-forward algorithm that can be generated by distorting the original tool path, and reduces the tool path errors and the total cutting time. The algorithm to generate a new tool path is represented as following; 1)calculating each distance of software acceleration/deceleration between two adjacent blocks, 2) estimating the distorted distance which is the adjacent-ratio-constant(k1, k2) multiply the distance of software acceleration/deceleration, 3) generating a 3-degree Bezier curve approximating the distorted tool path, 4) symmetrically transforming the Bezier curve about the intersection point between two blocks, and 5) connecting the transformed Bezier curve with the original tool path. The algorithm is applied to FANUC 0M. The study is to promote the high-precision machining and to reduce the total cutting time.

• Journal of the Korea Safety Management & Science
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• v.13 no.4
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• pp.109-116
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• 2011

This study examined into property of flour dust explosion to get the basic data for safety of industry by protecting accident of dust explosion. The experiment was conducted to know the effect of distance between explodes in the experiment device, effect of flour dust concentration, effect of humidity, effect of explosion pressure to the dust concentration and effect of inactive substance additive. The study indicated that explosion was happened effectively at the optimum distance 100mm or less in inter-polar distance, and minimum ignition energy was measured at 6mm. The data of feed concentration to the probability of explosion showed that the smaller the particle diameter was, the larger probability of explosion was, and the higher the dust concentration was, the more increased the pressure of explosion was, but more than upper limit of dust concentration, then the explosion of pressure decreased. For the effect of humidity, the more it contained water, the more decreased the ignition energy of dust was, so increased minimum explosive concentration, and effective water content was minimum 10% or more. Inactive substance additive was effective in adding more than 15% CaCO3 and CaO as substance inhibiting dust explosion, in which CaCO3 was more effective than CaO. the analysis of the flame of dust explosion was performed by high-speed video camera, it showed the size of flame bacame smaller in order that sub feed, main feed, wheat powder. As a result, sub feed was expected to be less dangerous than others.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.55-65
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• 2012

In the winter season, when the ventilation system is operating, the fresh cold air from the slot-type openings of broiler house which directly reached the animal zone can cause various problems such as thermal stress, decreasing of feed and water consumption, occurrence of respiratory disease, and etc. Therefore it is very important to control the trajectory of aero-flow from the slot openings to induce an efficient thermal heat change. Jet-drop distance model was proposed to predict and control the jet-trajectory. However their study was restricted due to the small scaled model and difficulties of measuring the Jet-drop distance. In this study, CFD was applied to analyze qualitatively and quantitatively the jet-drop distance in a real broiler house. The various variables were considered such as installed slot-angle, designed ventilation rate, and the outdoor ambient temperature. From the present study, two linear-regression models using the Jet-drop factor and corrected Archimedes number, and their R-squared values 0.744 and 0.736, respectively, were used. From this study, the applicability of CFD on the analysis of Jet-drop distance model was confirmed.