• Design & Manufacturing
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• v.11 no.2
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• pp.46-50
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• 2017

EPS used in lost foam casting elastic modulus is extremely low. So it is necessary to derive machining conditions for effective cutting. Therefore this study were analyzed end-milling machining conditions to affecting the surface roughness of EPS foam. The machining conditions were set to depth, feed, and RPM at 3-level. And 18experimental conditions were derived using mixed orthogonal array. The most important condition for surface roughness is RPM. In addition, RPM machining condition range test that can realize surface roughness less than $10{\mu}m$ was performed. he range of RPM conditions is more than 15,000. However the range of RPM conditions is a condition that is difficult to use in actual field. In the future variance analysis and experiments are needed to derive the range of machining conditions available.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.754-758
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• 2017

In this paper, we designed and manufactured an automatic control system to minimize or avoid damage by automatically controlling ship engines in case of fog to allow for safer operation. This automatic power control system uses ATmega128 and an RPM detection circuit to measure RPM changes by artificially generating fog in the fog generator. For this purpose, we have created a complete schematic and applied our source code to an ATmega128 for PWM control using a Hall sensor motor. In future, an experiment and safety evaluation using this automatic power control system with an actual ship will be prepared.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.5
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• pp.103-110
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• 2018

The modern aircraft consists of tens/hundreds of thousands of components. A large proportion of these components are manufactured using a machining process. A deburring process must be performed after to machining. This study investigates the effect of changes in the deburring wheel rpm on the deburring force and radius. The deburring wheel is used to trim sharp edges off machined parts of the aircraft. The deburring wheel used consists of a core and a nylon hair(this new concept is protected under patent). We find that higher deburring wheel rpm results in increased deburring force and radius. For deburring wheel rotation rates of 500~750rpm, deburring force of 3.4~6.5kgf and deburring radius of 0.4~0.5mm were observed.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1822-1831
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• 2015

This study was carried out to optimize coating process of the rice snack added with dried shrimp powder by using single extruder. A total of 8 independent variables were used for 4 independent variables of edible oil coating and 4 independent variables of seasoning coating. 4 independent variables for edible oil coating were set up as 10, 15, 20, 25 and 30% for the content of edible oil; 40, 50, 60, 70 and $80^{\circ}C$ for the tumbler temperature; 60, 70, 80, 90 and 100 rpm for the tumbler speed; 2, 3, 4, 5 and 6 min for the coating time. 4 independent variables for seasoning coating were set up as 2, 3, 4, 5 and 6% for the content of seasoning; 40, 50, 60, 70 and $80^{\circ}C$ for the tumbler temperature; 50, 60, 70, 80 and 90 rpm for the tumbler speed; 2, 3, 4, 5 and 6 min for the coating time. The characteristics of the dependent variables as coating yield and Breaking ratio of collet due to the condition changes of the independent variable was studied during process of edible oil coating and seasoning coating, respectively. As a results of this study, 20% of edible oil content, $70^{\circ}C$ of tumbler temperature, 80 rpm of tumbler speed, 4 min of coating time for process of edible oil coating, 3% of seasoning content, $60^{\circ}C$ of tumbler temperature, 70 rpm of tumbler speed, 3 min of coating time for process of seasoning coating were found to be the most preferable over other independent variables for the production of snack. In conclusion, it is necessary to set the independent variable in order to produce the high quality snack added with the rice as the main raw material and dried shrimp, edible oil and seasoning as the sub-materials.

• Progress in Medical Physics
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• v.22 no.3
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• pp.107-116
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• 2011

Respiratory gated radiation therapy and stereotactic body radiation therapy require identical tumor motions during each treatment with the motion detected in treatment planning CT. Therefore, this study developed a tumor motion monitoring and analysis system during the treatments employing RPM data, gated setup OBI images and a data analysis software. A respiratory training and guiding program which improves the regularity of breathing was used to patients. The breathing signal was obtained by RPM and the recorded data in the 4D console was read after treatment. The setup OBI images obtained gated at 0% and 50% of breathing phases were used to detect the tumor motion range in crenio-caudal direction. By matching the RPM data recorded at the OBI imaging time, a factor which converts the RPM motion to the tumor motion was computed. RPM data was entered to the institute developed data analysis software and the maximum, minimum, average of the breathing motion as well as the standard deviation of motion amplitude and period was computed. The computed result is exported in an excel file. The conversion factor was applied to the analyzed data to estimate the tumor motion. The accuracy of the developed method was tested by using a moving phantom, and the efficacy was evaluated for 10 stereotactic body radiation therapy patients. For the sine wave motion of the phantom with 4 sec of period and 2 cm of peak-to-peak amplitude, the measurement was slightly larger (4.052 sec) and the amplitude was smaller (1.952 cm). For patient treatment, one patient was evaluated not to qualified to SBRT due to the usability of the breathing, and in one patient case, the treatment was changed to respiratory gated treatment due the larger motion range of the tumor than treatment planed motion. The developed method and data analysis program was useful to estimate the tumor motion during treatment.

• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.179-185
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• 2006

This study was conducted to evaluate canal configuration after shaping by $ProTaper^{TM}$ with various rotational speed in J-shaped simulated resin canals. Forty simulated root canals were divided into 4 groups, and instrumented using by $ProTaper^{TM}$ at the rotational speed of 250, 300, 350 and 400 rpm. Pre-instrumented and post-instrumented images were taken by a scanner and those were superimposed. Outer canal width, inner canal width, total canal width, and amount of transportation from original axis were measured at 1, 2, 3, 4, 5, 6, 7 and 8 mm from apex. Instrumentation time, instrument deformation and fracture were recorded. Data were analyzed by means of one-way ANOVA followed by Scheffe's test. The results were as follows 1. Regardless of rotational speed, at the $1{\sim}2mm$ from the apex, axis of canal was transported to outer side of a curvature, and at 3~6 mm from the apex, to inner side of a curvature. Amounts of transportation from original axis were not sienifcantly different among experimental groups except at 5 and 6 mm from the apex. 2. Instrumentation time of 350 and 400 rpm was significantly less than that of 250 and 300 rpm (p<0.01). In conclusion the rotational speed of $ProTaper^{TM}$ files in the range of $250{\sim}400rpm$ does not affect the change of canal configuration, and high rotational speed reduces the instrumentation time. However appearance of separation and distortion of Ni-Ti rotary files can occur in high rotational speed.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.140-140
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• 2003

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2058-2062
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• 2005

This article describes the useful way to measure the torque and RPM of the geared motor. For this, we have made the planetary geared reduction motor including the torque sensor unit which consists of hall effects sensor and permanent magnet. Our monitoring system displays the sensing values (torque, rpm) and the calculated value (power) and it also has the network capability using the Bluetooth protocol. We will show that our solution is much more inexpensive and simple method to measure torque and rpm than before.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.512-516
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• 2001

It is recent trend that the manufactures of refrigerator use BLDC motor which RPM is changed by voltage of DC power, instead of induction motor in order to reduce energy consumption and noise radiation. It can be controlled two or more RPM suitable to environmental condition. For example it is operate much lower RPM than normal(usual) in the night. This paper introduce the method of noise control in the case of using BLDC Fan motor for refrigerator.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.359-364
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• 2006

This article describes the useful way to measure the torque and RPM of the geared motor. For this we have made the planetary geared reduction motor including 2 Hall sensors in it and the monitoring system. The monitoring system displays the sensing values (torque, rpm) and the calculated value (power) and it also has the network capability using the Bluetooth protocol. We will show that our solution is much more inexpensive and simple method to measure torque and rpm than before.