• Journal of Mechanical Science and Technology
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• v.18 no.12
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• pp.2182-2189
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• 2004

In the recent years, environmentally conscious design and manufacturing technologies have attracted considerable attention. The coolants, lubricants, solvents, metallic chips and discarded tools from manufacturing operations will harm our environment and the earth's ecosystem. In the present work, the Tukey method of multiple comparisons is used to select the minimum level of coolant required in a turning process. The amount of coolant is varied in 270 designed experiments and the parameters cutting temperature, surface roughness, and specific cutting energy are carefully evaluated. The effects of coolant mix ratio as well as the amount of coolant on the turning process are studied in the present work. The cutting temperature and surface roughness for different quantity of coolant are investigated by analysis of variance (ANOVA) - test and a multiple comparison method. ANOVA-test results signify that the average tool temperature and surface roughness depend on the amount of coolant. Based on Tukey's Honestly Significant Difference (HSD) method, one of the multiple comparison methods, the minimum level of coolant is 1.0 L/min with 2% mix ratio in the aspect of controlling tool temperature. F-test concludes that the amount of coolant used does not have any significant effect on specific cutting energy. Finally, Tukey method ascertains that 0.5 L/min with 6% mix ratio is the minimum level of coolant required in turning process without any serious degradation of the surface finish. Considering all aspects of cutting, the minimum coolant required is 1.0 L/min with 6% mix ratio. It is merely half the coolant currently used i.e. 2.0 L/min with 10% mix ratio. Minimal use of coolant not only economically desirable for reducing manufacturing cost but also it imparts fewer hazards to human health. Also, sparing use of coolant will eventually transform the turning process into a more environment-conscious manufacturing process.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.80-86
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• 2004

With the increasing demand of environmentally clean machining in recent years, the use of coolants has been restricted extensively. In this paper, a multiple comparison method(Tukey's HSD method) is proposed to choose the optimum level of coolant necessary for an efficient and environmentally clean machining. The cutting temperature, specific cutting energy, and surface roughness in turning process are analysed by ANOVA(Analysis Of Variance) and Tukey's HSD method. From the experimental results and statistical analysis, it is found that the optimum condition of coolant level is 10 ml/min with 6% mix ratio, which is almost half of the commonly used level.

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.455-461
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• 2014

The purposes of this study were to reveal the kinematic and kinetic difference of hard ground soccer shoe, firm ground soccer shoe and soft ground soccer shoe. Soccer players were shoes of varying stud designs with some preferring the bladed studs while others opting for the conventional studded stud. Statistics were used one way-ANOVA and Tukey's Honestly Significant Difference Method. Seven healthy college soccer players were attended a test. All parameters were recorded using the Zebris system. Spatio-temporal variables were no significant difference. Lateral symmetry was statistically significant differences (p<.05). Vertical GRF parameters were no significant difference. Medial midfoot pressure, lateral midfoot pressure and central forefoot pressure were statistically significant differences (p<.05). This study demonstrates that playing surface significantly affects difference soccer shoes during soccer game. Furthermore, epidemiological investigation is warranted to determine the effects of playing surfaces on sport specific injury mechanisms.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.110-115
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• 2001

In this paper, a multiple comparison was proposed to minimize the amount of coolant. And new coolant level, called "low level", was suggested to show usefulness of multiple comparison for experiments. The amount of this levee is about 1/4 of conventional coolant amount-called "high level", and dry cutting is called "none level". Using these coolant levels, the cutting temperatures of each coolant level in turning process were analyzed by analysis of variance(ANOYA)-test and a multiple comparison. As the result of ANOVA-test, we have just known that the average of temperature of each coolant level is not equal. However by Tukey's HSD, one of multiple comparison. it was analyzed that the average of temperature of low level is similar to that of high levee and different from that of none level.erent from that of none level.

• Journal of Technologic Dentistry
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• v.43 no.3
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• pp.77-83
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• 2021

Purpose: The purpose of this in vitro study was to measure and compare the thickness-dependent color dimensions of digital light processing (DLP) three-dimensional (3D) printer and conventional interim restorative resin. Methods: Specimens (N=60) were fabricated using either subtractive manufacturing (S group) or DLP 3D printing (D group) material. All milled and 3D-printed specimens were allocated into three different groups (n=10) according to different thicknesses as follows: 1.0, 1.5, and 2.0 mm. Color measurements in the CIELab coordinates were made using a spectrophotometer under room light conditions (1,003 lux). The color differences (𝚫E^*) between the specimen and control target data were calculated. Data were analyzed using the oneway analysis of variance (ANOVA). Post hoc comparisons were conducted using Tukey's honestly significant difference method (α=0.05 for all tests). Results: The 𝚫L^*, 𝚫a^*, 𝚫b^*, and 𝚫E^* values of interim restorative resin produced by DLP 3D printing were obtained in terms of the specimen's thickness increased compared with the increases by subtractive manufacturing. When the thickness was similar, the color difference between subtractive manufacturing and DLP 3D printing was ≥5.5, which is a value required by the dentist for remanufacturing. Conclusion: Color was influenced by the thickness of the interim restorative resin produced by DLP 3D printing.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.197-207
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• 2011

The study aimed at examining how different reline resins affect flexural strength and flexural modulus of denture base. A total of 80 specimens ($64{\times}10{\times}3.3$ mm, according to ISO 1567:1999) of heat-polymerized resin, 40 specimens for (Lucitone199(Dentsply Int., NewYork, USA), SR Ivocap(Ivoclar AG, Schaan, Liechtenstein)) respectively, were polymerized according to the manufacturer's instructions and divided into eight groups(n = 10). Control group specimens remained intact. Specimens in the other groups were abraded on both sides to 2 mm thickness, and were relined in 1.3 mm thickness with 3 types of resins (Lucitone199(Dentsply), SR Ivocap(Ivoclar), and Rebase II(Tokuyama Co., Ltd, Tokyo, Japan)). All specimens were preserved in distilled water at $37^{\circ}C$ for 50 hours, and then were subjected to flexural strength testing in a universal testing machine using 3-point loading. A crosshead speed of 5 mm/min was used, and the distance between the supports was 50 mm. Data analyses included one-way analysis of variance(ANOVA) and the Tukey Honestly Significant Difference test (p=.05). Both heat-polymerized resin groups and auto-polymerized resin groups showed statistically low flexural strength and flexural modulus than control groups. Specimens relined with Lucitone 199 showed significantly higher flexural strength and flexural modulus than those relined with SR-Ivocap. Specimens relined with auto-polymerized resin showed significantly lower flexural strength and flexural modulus than those relined with heat-polymerized resin. Relining with heat-polymerized resins showed superior mechanical properties to relining with an auto-polymerized resin. Relining with the same heat-polymerized resin as the denture base does not affect mechanical properties of a denture. Lucitone199 using a compression-mould technique resulted in the highest flexural strength.