• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.169-171
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• 2012

Although work-efficiency of construction machinery is a critical factor for estimating its workable-quantity per unit time, the coefficient figure table presented in the Poom-Sam that is used for Construction Cost Estimation of public sectors in Korea is very subjective for practical usage. In order to suggest objective work-coefficient table for a Tub Grinder, domestic and overseas documentary records were investigated and on-going construction sites were also visited. The research found that the table can be revised by means of detailing down by several factors. The research will be the foundation for applying the rapid development of Construction Equipment and technology to the appropriate cost estimations and the ground work of related studies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.557-558
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• 2006

In this study, the ultra precision centerless grinder for ferrule grinding was designed. As the good-qualified ferrule is required a precise and fine grinding, grinding machine for ferrule must have a high accuracy and a sufficient stiffness. The centerless grinder is composed of the high damping concrete bed, grinding wheel spindle unit, regulating wheel spindle unit, feeding table and dressing unit. For a newly developed centerless grinder, hydrostatic system with high precision feeding and high stiffness was proposed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.5
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• pp.40-45
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• 2003

Optical and electronic industries are using lapping and polishing processing as a final finish rather than grinding, because they need more accurate parts of brittles non-metallic materials such as single crystals. Sapphire has been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing process.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.328-335
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• 2021

Considerable differences exist in the characteristics of size reduction and classification because of biomass species. Miscanthus sacchariflorus (M. sacchariflorus) Goedae-Uksae 1 is not used efficiently because of the imperfections of the processing technology for this biomass. Therefore, for the best use of specific biomass, improvement in the feedstock preparation of the biomass for processing, such as pellet manufacturing, is necessary. In this study, a laboratory-scale cone grinder and air classifier were designed and combined to investigate the performance of the combination system for M. sacchariflorus. The average equivalent spherical diameter of particles showed a close relationship with air velocity for air classification. The air velocity range to classify proper particles for pelletization was determined to be 6.0-6.8 m/s. The mass ratios of the collected particles to feed mass for four lengths of chopped M. sacchariflorus were 45.1%:46.1%, 39.1%:46.6%, and 44.1%:52.8% at the first, second, and third steps in simulating the multistep combination system, respectively.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.422-427
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• 2003

Sapphire have been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing Process.

• Journal of Ocean Engineering and Technology
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• v.31 no.6
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• pp.419-424
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• 2017

Unlike other leisure boats, a sailing yacht is propelled by wind power using sails that are controlled by the crew. Therefore, the ergonomic design of the equipment that the crew has to operate for sailing might be very important. However, it is difficult to find design rules and regulations for the equipment arrangement of a sailing yacht based on ergonomics. In this study, the arrangement design for the height and side plate angle of a winch for a sailing yacht was examined from an ergonomic design point of view. In a simulation, a Korean male in his 20s was selected as a human model for a grinder. The physical load was analyzed when he was operating a winch using a 3D human simulation. The lower back load showed the highest value when using the grinder at $90^{\circ}$ and $180^{\circ}$. Based on the results for the lower back load when using the grinder with various winch heights, it is suggested that the winch height from the cockpit floor to the top of the winch should be more than 40% of the height of the human operator. In addition, according to the results for the lower back load with various horizontal distances from the body, it is suggested that the side plate angle should be less than $16^{\circ}$.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.1008-1015
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• 2012

Sulgidduk is a kind of basic steamed rice cake in Korea. Multifunctional portable grinder was used for making sulgidduk and investigated the characteristic changes of rice powder for deciding the proper particle size of rice powder. Operation times for grinding the water absorbed swelled rice were 10, 20, 30 and 40 seconds. Moisture contents of rice powder and sulgidduk showed an increasing tendency with an increase of operation times for grinding. Springiness showed significant differences according to the operation times. Cohesiveness was decreased severely after 40 seconds grinding. Chewiness showed high after 20 seconds grinding in all groups; however, decreased after 40 seconds grinding and showed similar chewiness of the control group. Fracturability also showed severe increased tendency after 20 seconds grinding and decreased after 30 seconds grinding. Strength and hardness showed significant differences; they were increased until 30 seconds and severely decreased after 40 seconds grinding. L values showed significant differences in all the groups ($p{\leq}0.05$). The a and b values did not show any differences in all groups. Overall sensory evaluations, such as colors, flavors and texture, were increased with operation times for grinding and showed significant differences among the groups (p<0.05). As a result of this study, 40 seconds grinding times were the best condition for making sulgidduk, using by multifunctional grinder.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1008-1013
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• 2003

This paper concerns the structural characteristic analysis and evaluation on the hydrostatic guide way and feeding system of a high precision centerless grinder for machining ferrules. In order to realize the required accuracy of ferrules with sub-micron order, the axial stiffness and motion accuracy of feeding system have to become higher level than those of existing centerless grinders. Under these points of view, the physical prototype of feeding system consisted of steel bed, hydrostatic guide way and ballscrew feeding mechanism is designed and manufactured for trial. Experimental results show that the axial and vertical stiffnesses of the physical prototype are very low as compared with those design values. In this paper, to reveal the cause of these stiffness difference, the structural deformations on the virtual prototype of feeding system are analyzed based on the finite element method under experimental conditions. The simulated results illustrate that the deformation of front ballscrew support-bearing bracket is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.896-903
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• 2004

This paper proposes the structural characteristic analysis and evaluation on the hydrostatic guide way and feeding system of a high-precision centerless grinder for machining ferrules. In order to realize the required accuracy of ferrules with sub-micron order, the axial stiffness and motion accuracy of feeding system have to become higher level than those of existing centerless grinders. Under these points of view, the physical prototype of feeding system composed of steel bed, hydrostatic guide way and ballscrew feeding mechanism is designed and manufactured for trial. Experimental results show that the axial and vertical stiffnesses of the physical prototype are very low as compared with those design values. In this paper, to reveal the cause of these stiffness difference, the structural deformations on the virtual prototype of feeding system are analyzed based on the finite element method under experimental conditions. The simulated results illustrate that the deformation of front ballscrew support-bearing bracket is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system.

• Culinary science and hospitality research
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• v.20 no.6
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• pp.262-274
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• 2014

In this study, changes of nutrients such as vitamins, minerals, and antioxidants were determined by using a multi-functional grinder. Contents of vitamin C and vitamin $B_1$ were measured by HPLC, and antioxidant activity was estimated toward free radical scavenging effect in using DPPH. Contents of minerals(Zn, Mn, Fe, Mg, K, and Ca) were computed by ICP-Mass. Results identified that the contents of vitamin C was $44.06{\pm}10.86mg/kg$ in mandarine, $132.1{\pm}22.80mg/kg$ in orange, and $12.79{\pm}2.01mg/kg$ in pineapple by using the hand blender for 3 minutes, and the loss rate of vitamin C contents were 12%, 7%, and 12% in comparison with the control group. In addition, the contents of vitamin C were $41.89{\pm}5.55mg/kg$ in mandarine, $131.51{\pm}12.67mg/kg$ in orange and $16.76{\pm}1.47mg/kg$ in pineapple when using of the grinder for 3 minutes, and the loss rate of vitamin C contents were 16%, 8%, and 17%. The results of vitamin $B_1$ showed a tendency to decrease in the same manner as the content of vitamin C even if there was no significant difference. Furthermore, the result of antioxidant activity revealed that free radical scavenging effect of sample was 60% decreased when using a hand blender and 10% decreased when using a grinder. Thus decrease rate of antioxidant activity when using the hand blender was higher than grinder. Lastly, current study could find any significant differences among the 16 food samples for cooking when employing the multi-functional grinder(p<0.05).