• Membrane and Water Treatment
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• v.9 no.6
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• pp.435-445
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• 2018

In this work, desalination experiments were performed on vacuum membrane distillation (VMD). Process parameters such as feed flow rate, vacuum degree on permeate side, feed bulk temperature and feed salt concentration were optimized using sensitivity analysis and Taguchi method. The optimum values of process parameters were found to be 2 lpm of feed flow rate, $60^{\circ}C$ of feed bulk temperature, 5.5 kPa of permeate-side pressure and 5000 ppm of salt concentration. The permeate flux at these conditions was obtained as $26.6kg/m^2{\cdot}hr$. The rejection of salt in permeate was found to be 99.7%. The percent contribution of various process parameters using ANOVA results indicated that the most important parameter is feed bulk temperature with its contribution of 95%. The ANOVA results indicate that the percent contribution of permeate pressure gets increased to 5.384% in the range of 2 to 7 kPa as compared to 0.045% in the range of 5.5 to 7 kPa.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.71-78
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• 2020

The rotary feed axes of a 5-axis machine tool can increase the freedom of the tool posture, while reducing feed speed and rigidity. In addition, as a ball-end mill is inevitably used during machining by rotational feed, the step-over length is reduced compared to the flat-end mill, thereby reducing the material removal rate. Therefore, this study attempts to improve the material removal rate, feed speed, and machining stability using the corner radius flat-end mill and a fixed controlled machining method for the rotary feed axes during roughing. In addition, the tapered ball-end mill and simultaneously controlled machining method for the rotary feed axes were used for finishing to improve the propeller's 5-axis machining efficiency by enhancing the surface quality. In order to create the tool path effectively and easily, we propose a specific approach for using the propeller's geometric properties and evaluate the effectiveness of the proposed method by comparing it with the method of the dedicated module.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.1
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• pp.14-21
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• 2012

The effects of cutting condition and tempering temperature for the shape of cutting chip were investigated. For this purpose, a lead-free brass containing 1wt.% of Bi extruded at $750^{\circ}C$ in straight turning was used in this study. The cutting chip preferred was mainly found to be loose form of arc chips with curling discontinuity, and these were formed by shear fracture. However, some of fragmental element chip were found to be mixed when tempering temperature was as high as $500^{\circ}C$. The form and size of chip was more affected by feed rate than by tempering temperature and cutting rate. In addition, the cutting surface was observed to be formed more rough in the case of high feed rate and low cutting rate compared to low feed rate and high cutting rate.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.680-695
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• 1998

The objective of this study is to optimize the responses of the creep feed ceramic grinding process simultaneously by an off-1ine multicriteria optimization methodology. The responses considered as objectives are material removal rate, flexural strength, normal grinding force, workpiece surface roughness and grinder power. Alumina material was ground by the creep feed grinding mode using superabrasive grinding wheels. The process variables optimized for the above objectives include grinding wheel specification, such as bond type, mesh size, and grit concentration, and grinding process parameters, such as depth of cut and feed rate. A weighting method transforms the multi-objective problem into a single-objective programming format and then, by parametric variation of weights, the set of non-dominated optimum solutions are obtained. Finally, the multi-objective optimization methodology was tested by a sensitivity analysis to check the stability of the model.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.68-75
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• 2005

This paper presents a new method for the optimization of feed rate in sculptured surface machining. A NC verification model based on Z-map was utilized to obtain chip load according to feed per tooth. This optimization method can regenerate a new NC program with respect to the commanded cutting conditions and the NC program that was generated from CAM system. The regenerated NC program has not only the same data of the ex-NC program but also the updated feed rate in every block. The new NC data can reduce the cutting time and produce precision products with almost even chip load to the feed per tooth. This method can also reduce tool chipping and make constant tool wear.

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.745-754
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• 2020

The dye marker Sudan Red 7B was tested as an effective and appropriate marking method for searching the territory of the termite, Reticulitermes speratus, in Korea. The sensitivity of termites to the dye marker was evaluated by measuring the feed consumption amount, survival rate, retention time, and transfer efficiency of R. speratus according to the concentration and feeding period of Sudan Red 7B. As the concentration conditions of dye marker increase, Sudan Red 7B remarkably reduced the feed consumption of the termites. The survival rate was not significantly different from that of the control group (more than 90%), except when feed containing 1% or 2% concentrations of the dye marker was given for five days. The duration of the marking effect persisted for seven days, even at a concentration of 2% dye marker in the feed. No dye transfer by trophallaxis occurred between termites marked with Sudan Red 7B and unmarked termites.

• Journal of Aquaculture
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• v.10 no.3
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• pp.311-320
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• 1997

The experiment was conducted t determine the effects of water temperature and daily feeding rate on Koran rockfish growth. The first experiment was carried out to know the growth of the fish in the different water temperature. The second experiment was carried out to know the effects of feeding rate of the fish. In the first experiment, feed efficiency was unaffected by the different water temprature 12, 15 and $18^{\circ}C$, but feed intake and growth rate were affected by the water temperature. Feed intake and growth rate of the fish reared in $15^{\circ}C$ were higher than those of the other groups. In the second experiment, feed efficiency was unaffected by feeding rate except the starve group. Daily growth rate of the fish fed 1.0% diet/BW or more. HSI, VSI, condition factor, GOT, GPT, TG, GL and Ht of fed groups were unaffected by the feeding rate in the experiment. Absoption ratios of protein and lipid were not different with the different feeding rates in fed fish groups. These results indicate that the optimum daily feeding rate of yearling Korean rockfish is about 70-80% of satiation rate.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.321-322
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• 2002

This paper presents study of effects of cutting parameters such as cutting speed, feed rate and depth of cut on the surface roughness in hard turning. Taguchi Method and linear regression model of design parameters were utilized to identify the controlling process parameters that can monitor the surface roughness in the hard turning operation. In the process optimization, experimental planning was performed using the orthogonal array and concept of the signal-to-noise ratio. Cutting parameters such as speed, feed rate, and depth of cut were selected as process parameters and the ANOVA analysis showed that feed rate and cutting speed had more effect on the roughness variation that depth of cut.

• Structural Engineering and Mechanics
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• v.73 no.6
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• pp.631-640
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• 2020

Using backup plate is one of the most commonly used methods to decrease drilling-induced delamination of composite laminates. It has been shown that, the size of the delamination zone is related to the vertical element of cutting force named as thrust force. Also, direct control of thrust force is not a routine task, because, it depends on both drilling parameters and mechanical properties of the composite laminate. In this research, critical feed rate and thrust force are predicted analytically for delamination initiation in drilling of composite laminates with backup plate. Three common theories, linear elastic fracture mechanics, classical laminated plate and mechanics of oblique cutting, are used to model the problem. Based on the proposed analytical model, the effect of drill radius, chisel edge size, and backup plate size on the critical thrust force and feed rate are investigated. Experimental tests were carried out to prove analytical model.

• Journal of Welding and Joining
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• v.24 no.5
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• pp.67-73
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• 2006

Laser welding is suitable for welding to the aluminum alloy sheet. In order to apply the aluminum laser welding to production line, parameters should be optimized. In this study, the optimal welding condition was searched through the genetic algorithm in laser welding of AA5182 sheet with AA5356 filler wire. Second-order polynomial regression model to estimate the tensile strength model was developed using the laser power, welding speed and wire feed rate. Fitness function for showing the performance index was defined using the tensile strength, wire feed rate and welding speed which represent the weldability, product cost and productivity, respectively. The genetic algorithm searched the optimal welding condition that the wire feed rate was 2.7 m/min, the laser power was 4 kW and the welding speed was 7.95 m/min. At this welding condition, fitness function value was 137.1 and the estimated tensile strength was 282.2 $N/mm^2$.