• Journal of Advanced Marine Engineering and Technology
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• v.18 no.4
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• pp.62-68
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• 1994

Recently, the trends toward reduction in size and weight of industrial products increased the application of micro hole for manufacturing gadgets of high precision and gave rise to a great deal of interest for micro hole drilling M/C. Quite a few research work is performed on micro drilling on domestic basis compared with the tendency of analyzing cutting mechanism, adaptive control, monitoring of generally available drills of diameter greater than 1mm. This study adresses the design, manufacturing and controlling a micro hole drilling M/C with the overload detection instrument and the step feed mechanism. Controlling and monitoring of the drilling process are acomplished on PC basis for more user interfaces and effectiveness. The test machine of the results of this research shows a good foundation for extending further micro hole machining technique.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.47-53
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• 2006

An Experiment was carried out to find the scheme far minimization of burr formation on inclined exit surface in drilling. Several drills with different geometry are used for drilling the workpiece with inclined exit surface. Step drills are specified with step angle and step size. The influence of the inclination angle of exit surface on burr formation was observed, which enables to analyze the burr formation mechanism on inclined exit surface. Along the edge on the inclined exit surface, burrs are formed by the bending deflection to feed direction and also burrs are formed in exit direction of cutting edge. To minimize the burr formed in feed direction, the corner angle which is formed by the inclination angle and step angle must be large enough not to be bent to burr. By decreasing step angle of drill and decreasing the distance between two axes of two holes, burr formation at the intersecting holes can be minimized. Burr formation mechanisms are analyzed according to the drill geometries and cutting conditions. Several schemes far burr minimization on inclined exit surface were proposed.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.197-199
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• 1986

To meet tight tolerance requirements of mass produced shafts which are subcomponents of automobile parts, an automated measuring system has been developed. The system comprises of a non-contact shaft diameter measuring instrument using laser, a feed mechanism of a step motor and ball screw and a personal computer. The system can determine pass-fail of the piece under test and also analyze data for statistical process control.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.136-136
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• 2017

By-products has been considered lately in Total Mixed Ration (TMR) as an alternative to livestock feed around the world. This is due to the high cost of using forage as feed, less expense in exploring by-products of agriculture origin and environmental concerns with their disposal. However, by-products usually contain contaminants and the production process requires fermentation using a storage and fermentation tank. Animal feed is the start point of the food safety chain in the 'farm-to-fork' model. This necessitated a study to model a protocol that will culminate to safe feed production. Hazard analysis and critical control points (HACCP), a systematic preventive approach to food safety from biological, chemical and physical hazards in production processes that can cause the finished product to be unsafe was explored. Implementation of this model provides a mechanism that ensures product safety is continuously achieved. The entire production process of By-products feed production was evaluated using HACCP wizard software. This includes the plant layout, technical standards, storage and fermentation tank cleansing method, staff assignment, safety control method, and distribution. The potential biological, chemical, and physical hazards that may exist in every step of the production process were identified, and then critical control points (CCPs) were selected. This will ensure the safety of products made from livestock that consumes by-product feed. These includes cheese, milk, beef, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.304-307
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• 2002

High speed machining was accomplished. through the technological advances which covers the whole field of mechanical industry. But tapping have many troubles because of its complicate cutting mechanism, for example. tool damage, chip elimination and synchronization between spindle rotation and feed motion. But High speed tapping is so important that it marches in step with the flow of the times and make improvement in the productivity. In this paper we analyze mechanism of high speed synchronized tapping with the signal of tapping torque and spindle speed obtained through the newly developed high speed tapping machine(NTT-30B). We made an experiment with this machine on condition of various speed from 1000rpm to 10000rpm. As one complete thread is performed through the whole chamfer cutting, cutting torque increases highly in chamfer cutting, but smoothly in full thread cutting functioning of the threads guide. And the size of cutting torque according to spindle speed(rpm) was not enough of a difference to be conspicuous.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.300-307
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• 1993

The phase-transfer polymerization of methyl methacrylate with tricaprylmethylammonium chloride-$Na_2S_2O_4-CCl_4$ initiator system was investigated in an aqueous-organic two-phase system. The observed rates of polymerization were compared with those obtained from the polymerization mechanism proposed with a cyclic phase-transfer initiation step. The rate of polymerization was found to be proportional to the concentration of $Q^+$ and square root of ${S_2O_4}^{-2}$ in the aqueous solution and the feed quantity of $CCl_4$ and MMA.

• ALGAE
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• v.29 no.2
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• pp.137-152
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• 2014

Mixotrophic protists play diverse roles in marine food webs as predators and prey. Thus, exploring mixotrophy in phototrophic protists has emerged as a critical step in understanding marine food webs and cycling of materials in marine ecosystem. To investigate the feeding of newly described mixotrophic dinoflagellate Ansanella granifera, we explored the feeding mechanism and the different types of species that A. granifera was able to feed on. In addition, we measured the growth and ingestion rates of A. granifera feeding on the prasinophyte Pyramimonas sp., the only algal prey, as a function of prey concentration. A. granifera was able to feed on heterotrophic bacteria and the cyanobacterium Synechococcus sp. However, among the 12 species of algal prey offered, A. granifera ingested only Pyramimonas sp. A. granifera ingested the algal prey cell by engulfment. With increasing mean prey concentration, the growth rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but became saturated at a concentration of $434ngCmL^{-1}$ (10,845 cells $mL^{-1}$). The maximum specific growth rate (i.e., mixotrophic growth) of A. granifera feeding on Pyramimonas sp. was $1.426d^{-1}$, at $20^{\circ}C$ under a 14 : 10 h light-dark cycle of $20{\mu}Em^{-2}s^{-1}$, while the growth rate (i.e., phototrophic growth) under similar light conditions without added prey was $0.391d^{-1}$. With increasing mean prey concentration, the ingestion rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but slightly at the concentrations ${\geq}306ngCmL^{-1}$ (7,649 cells $mL^{-1}$). The maximum ingestion rate of A. granifera feeding on Pyramimonas sp. was 0.97 ng C $predator^{-1}d^{-1}$ (24.3 cells $grazer^{-1}d^{-1}$). The calculated grazing coefficients for A. granifera feeding on co-occurring Pyramimonas sp. were up to $2.78d^{-1}$. The results of the present study suggest that A. granifera can sometimes have a considerable grazing impact on the population of Pyramimonas spp.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.358-364
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• 2012

The kinetics of the Fischer-Tropsch synthesis and water gas shift reactions over a precipitated iron catalyst were studied in a 5 channel fixed-bed reactor. Experimental conditions were changed as follows: synthesis gas $H_2$/CO feed ratios of 0.5~2, reactants flow rate of 60~80 ml/min, and reaction temperature of $255{\sim}275^{\circ}C$ at a constant pressure of 1.5 MPa. The reaction rate of Fischer-Tropsch synthesis was calculated from Eley-Rideal mechanism in which the rate-determining step was the formation of the monomer species (methylene) by hydrogenation of associatively adsorbed CO. Whereas water gas shift reaction rate was determined by the formation of a formate intermediate species as the rate-determining step. As a result, the reaction rates of Fischer-Tropsch synthesis for the hydrocarbon formation and water gas shift for the $CO_2$ production were in good agreement with the experimental values, respectively. Therefore, the reaction rates ($r_{FT}$, $r_{WGS}$, $-r_{CO}$) derived from the reaction mechanisms showed good agreement both with experimental values and with some kinetic models from literature.