• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.646-652
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• 2015

In this study transmembrane pressure (TMP) was measured with respect to permeate flux through the submerged flat sheet membrane for the emulsion and semi-synthetic cutting oil solutions. The effective area and nominal pore size of the used microfiltration membrane were $0.02m^2$ and $0.15{\mu}m$, respectively. The experiments were carried out simultaneously for run/stop (R/S) and sinusoidal flux continuous operation (SFCO) modes using two submerged membrane module in the reservoir. TMP for the case of SFCO was maintained under 60% of R/S, and the effect on TMP drop decreased as the permeate flux increased for emulsion cutting oil solution. Membrane fouling for the semisynthetic solution showing low turbidity was induced lower comparing to the emulsion solution. Also, the effect on TMP drop for SFCO decreased during long-term operation.

• Membrane Journal
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• v.25 no.4
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• pp.320-326
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• 2015

In this study, permeation experiments were carried out using the symmetric and asymmetric sinusoidal flux continuous operation (SFCO) modes for the submerged flat sheet membrane in the 0.5 wt% emulsion type cutting oil solution. The effective area and nominal pore size of the used microfiltration membrane were $0.02m^2$ and $0.15{\mu}m$, respectively. The emulsion cutting oil was rejected over 99% based on turbidity. Transmembrane pressure increased lower as the aeration rates increased. The symmetric SFCO mode was a little more effective than the symmetric SFCO mode in low permeate flux between 10 and $15L/m^2{\cdot}h$. However, the symmetric SFCO mode was shown very effectively in high permeate flux between 25 and $30L/m^2{\cdot}h$.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.1
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• pp.27-33
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• 2003

Excessive heat generation at the implant-bone interface may cause irreversible bone damage and loss of osseointegration. The effect of heat generation in vitro at the implant surface caused by abutment reduction with high-speed dental turbine was examined. Titanium-alloy abutments connected to a titanium alloy screw-implant embedded in an acrylic-resin block in a $37^{\circ}C$ water bath were prepared. Temperature changes were recorded via embedded thermocouples at the cervix and apex of the implant surface. Analysis of variance for repeated measures was used to compare seven treatment groups. Fifty seconds of continuous cutting with air and water coolant caused a mean temperature increase of $1.24^{\circ}C$ at apex and $5.77^{\circ}C$ at cervix. Similar intermittent cutting caused increase of $2.50^{\circ}C$ at apex and $1.64^{\circ}C$ at cervix. But, continuous cutting with air coolant caused a mean temperature increase of $6.47^{\circ}C$ at apex and $5.77^{\circ}C$ at cervix. Similar intermittent cutting caused increase of $6.47^{\circ}C$ at apex and $5.77^{\circ}C$ at cervix. Preparation of implant abutment does not lead to detrimental effect on peri-implant tissues provided that adequate cooling. However, without water cooling, extreme overheating could be provoked, reaching the critical temperature that would lead to irreversible bone damage within only a few seconds.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.344-348
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• 2001

In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel grinding ceramic materials. Normal component of grinding resistance was decreasing while increase of spindle speed. The resistance of vitrified bond wheel was less then that of resinoid bond wheel because of imbedded large holes on the surface of cutting edge. Surface roughness was decreasing while increase of spindle speed. The surface roughness after using vitrified bond wheel was less than that of resinoid bond wheel because of small elastic deformation. After continuous grinding of ceramics, cutting edge ratio of resinoid bond wheel decreases. For the case of vitrified bond wheel, cutting edge ratio does not change.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.8-12
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• 2012

Recently, a wide range of industrial production area has a competitive advantage through cost reduction. Moreover with the development of industrial technology, base material and cutting tool help the machining technology. But most of the machining enterprises have not hold the R&D facilities and human resources. This mainly disturbs the industrial development and th increase of production efficiency. Especially in the interrupted machining process, it showed different behavior with continuous machining process. So it needs to research and develop the tool life and tool wear mechanism analysis.

• Journal of Animal Environmental Science
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• v.19 no.1
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• pp.9-18
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• 2013

Currently, there was no producing system of TMR for pig feeding in Korea. In this study, we examined unrolling, cutting, and softening for the round bale silage. We designed and developed the prototype system of round bale silage for pig feeding. Unroll method were lower chain conveying and upper belt conveying which includes an hydraulic vertical fodder knife. Gathering and cutting method were rotating auger and flywheel which have 10 cutters, input roller of 280 rpm, and cutter rotating speed of 1,750 rpm. Softening device was rotating hammer in inclined cylinder adjustable to $25^{\circ}C$ and rotating speed up to 1,300 rpm. The prototype system was integrated working for unrolling, cutting, and softening. We found that when the round bale silage in unrolling apparatus cut length of 20 cm to input cutting apparatus, the cutting performance was well in continuous working up to input rate of 1,000 kg/h, the softening apparatus was working well.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.842-846
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• 1997

Micro-hole drilling (holes less than 0.5 mm in diameter with aspect ratios larger than 10) is gaining increased attention in a wide spectrum of precision production industries. Alternative methods such as EDM, laser drilling, etc. can sometimes replace mechanical micro-hole drilling but are not acceptable in PCB manufacture because they yield inferior hole quality and accuracy. The major difficulties in micro-hold drilling are related to wandering motions during the inlet stage, high aspect ratios, high temperature,etc. However, of all the difficulties, the most undesirable one is the increase of drilling force as the drill penetrates deeper into hold. This is caused mainly by chip related effects. Peck-drilling is thus widely used for deep hole drilling despite the fact that it leads to low productivity. Therefore, in this paper, a method of cutting force regulation is proposed to achieve continuous drilling. A proportional plus derivative (PD) and a sliding modecontrol algorithm will be implemented for controlling the spinle rotational frequeency. Experimental results will show that sliding mode control reduces the nominal cutting force and its variation better than the PD control, resulting in a number of advantages such as an increase in drill life, fast stabilization of the wandering motion, and precise positioning of the hole.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1121-1140
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• 1992

In metal cutting the shape of generated chip varies according to cutting conditions, characteristics of workpiece and geometry of cutting tool. The best surface roughness of machined workpiece is obtained when generating flow type contrinuous chip. If the generated chip is not broken, that is not only tangled workpiece and cutting tool, but also may give damage on the machined surface of workpiece or danger for a operator. The flow type continuous chip may bring the low productivity in high speed any heavy cutting, automatic machining process and non-human factory. There are two type of chip break process ; controlling cutting condition and using chip breaker. In present study we carried out the experiment on new type chip breaker compared with conventional type and proved the efficiency of a new type and showed the chip break condition to be applied in actual metal cutting. In the experiment SM 20 C as a workpiece material and WC as a tool material were used and cutting speed of 30-150m/min, feed of 0.071-0.210mm/rev and depth of cut of 1mm were applied as cutting condition. The results of the experiment are as follows : (1) The mechanism of chip curl can be explained more clearly by plastic flow of workpiece material and moment of shearing force. (2) The most effective radius of curled chip and flat distance from cutting edge is 2.0-2.5mm and 1.5mm in both types. (3) The effective inclination angle of chip break surface and side cutting edge angle are 30.deg.- 45.deg. and 20.deg. in conventional type, while the radius of arc surface, lower arc angle A, upper arc angle B and side cutting edge angle are 3mm, 20.deg.- 45.deg., 0.deg.- 45.deg. and 10.deg.- 20.deg. in new type. (4) The probability to be obtained 100% chip breaking ratio is much higher in new type than in conventional type.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.2
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• pp.40-46
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• 1989

Recently, the researches on cutting the new material have been done for development of aerospace industrial engineering. Especially, titanium ally is well known as heat resisting, antiwear, anticorrosion and difficult-to-machine materials. Many studies on the analysis of shear angle have been done for improving productivity in cutting these materials. In case of titanium alloy, the saw-toothed type of chip which has wave surface of a triangular form, an eccentric from of a continuous type of chip that is produced in the cutting process, was checked. Nakayama supposed that a maximum shear strewss plane and the shear crack in the free surface made an angle of $45^{\circ}$ .deg. , but it's usually much larger than that. In this paper, the author analyzed the shear conditions of the cutting process in the quick-stopping device with the help SEM-photographs, and measured the hypotenuse angle directly in the photographs of the chips. In conclusion, the author tried to find the shear angle in the cutting process with the saw-toothed chip and compared it with the shear angles which can be calculated from the theories established by others. The results obtained are as follows. 1. In case of the saw-toothed chips, the equivalent cutting ratio can be calculated by using the chip thickness to two-thirds of ramp height. 2. The theory of Ernst-Merchant is not applicable to the titanium and its alloys which does not fractured in accordance with the theory of maximum shear stress. 3. When we cut the titanium alloys which produced the saw-toothed chips, the shear angle can be found with the theories of Rowe-Spick, P.K. Wright and the measurement of hypotenuse angle.

• Journal of KIBIM
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• v.12 no.4
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• pp.19-31
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• 2022

With the development of 3D-based CAD (Computer Aided Design), attempts at freeform building design have expanded to small and medium-sized buildings in Korea. However, a standardized system for continuous utilization of shape data and BIM conversion process implemented with 3D-based NURBS is still immature. Without accurate review and management throughout the Freeform building project, interference between members occurs and the cost of the project increases. This is very detrimental to the project. To solve this problem, we proposed a continuous utilization process of 3D shape information based on BIM parameters. Our process includes algorithms such as Auto Split, Panel Optimization, Excel extraction based on shape information, BIM modeling through Adaptive Component, and BIM model utilization method using ID Code. The optimal cutting reference point was calculated and the optimal material specification was derived using the Panel Optimization algorithm. With the Adaptive Component design methodology, a BIM model conforming to the standard cross-section details and specifications was uniformly established. The automatic BIM conversion algorithm of shape data through Excel extraction created a BIM model without omission of data based on the optimized panel cutting reference point and cutting line. Finally, we analyzed how to use the BIM model built for automatic conversion. As a result of the analysis, in addition to the BIM utilization plan in the general construction stage such as visualization, interference review, quantity calculation, and construction simulation, an individual management plan for the unit panel was derived through ID data input. This study suggested an improvement process by linking the existing research on atypical panel optimization and the study of parameter-based BIM information management method. And it showed that it can solve the problems of existing Freeform building project.