• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.46-53
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• 2014

An automatic grease lubricator provides an adequate amount of fresh grease constantly to any type of rotating machine to minimize friction heat and reduce friction loss. This study seeks to develop an automatic grease lubricator by means of rapid prototyping with a gear-driven mechanism and a controlled operation time. The ultimate design is to lubricate an adequate amount of grease by a simple dip-switch clicking mechanism according to an advanced set cycle. The backlash of the gear was minimized to increase the power, and to increase the power of the mechanism, the binding frequency and the thickness of the coil were changed. To control the rotation cycles of the main shaft according to certain set numbers, different resistances and chips were used in the design of the circuit which controls the electrical signals via a pulse. A digital mock-up was analyzed and the rapid prototyping (RP) trial products were tested with a PCB circuit and grease. An evaluation of the outlet capacity of RP trial products was conducted, as the friction caused by the outlet on the wall surface was an important factor in the operation of the equipment. Finally, a finishing process was applied to decrease the roughness of a surface to a comparable level to test the performance of the product.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.37-44
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• 2013

Generally, a reduced chemical mechanism of n-heptane is used as chemical fuel of a 3-D diesel engine simulation because diesel fuel consists of hundreds of chemical components and various chemical classes so that it is very complex and large to use for the calculation. However, the importance of fuel in a 3-D simulation increases because detailed fuel characteristics are the key factor in the recent engine research such as homogeneous charged compression ignition engine. In this study, normal paraffin, iso paraffin and aromatics were selected to represent diesel characteristics and n-dodecane was used as a representative normal paraffin to describe the heavy molecular weight of diesel oil (C10~C20). Reduced kinetics of iso-octane and toluene which are representative species of iso paraffin and aromatics respectively were developed in the previous study. Some species were selected based on the sensitivity analysis and a mechanism was developed based on the general oxidation scheme. The ignition delay times, maximum pressure and temperature of the new reduced n-dodecane chemical mechanisms were well matched to the detailed mechanism data.

• Health Policy and Management
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• v.23 no.4
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• pp.343-348
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• 2013

Background: Price control alone may not successfully restrain growth in health expenditures. This study aimed to propose fee adjustment model suitable for Korea reflecting health service volume and to clarify applicability of the model by comparing actual conversion factor with estimated conversion factor from simulation of this model. Methods: Fee adjustment model was developed based on Alberta's fee adjustment formula in Canada and 7 alternatives were assessed according to diversely applied parameters of the model. Results: Estimated conversion factors of the tertiary care hospital and the hospital were lower than actual conversion factors, since the utilization of heath service has been increased. However, there was no big difference between estimated conversion factors and actual conversion factors of the general hospital and the clinic. Eventually this fee adjustment model could estimate proper conversion factor reflecting health service volume. Conclusion: This model may be applicable to the mechanism as determining conversion factor between insurer and provider via negotiation and controling growth in health expenditures.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.123-129
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• 2012

Recently, interests on cleaning robots workable in pipes (termed as in-pipe cleaning robot) are increasing because Garbage Automatic Collection Facilities (i.e, GACF) are widely being installed in Seoul metropolitan area of Korea. So far research on in-pipe robot has been focused on inspection rather than cleaning. In GACF, when garbage is moving, the impurities which are stuck to the inner face of the pipe are removed (diameter: 300 mm or 400 mm). Thus, in this paper, by using TRIZ (Inventive Theory of Problem Solving in Russian abbreviation), an in-pipe cleaning robot of GACF with the 6-link sliding mechanism will be proposed, which can be adjusted to fit into the inner face of pipe using pneumatic pressure(not spring). The proposed in-pipe cleaning robot for GACF can have forward/backward movement itself as well as rotation of brush in cleaning. The robot body should have the limited size suitable for the smaller pipe with diameter of 300 mm. In addition, for the pipe with diameter of 400 mm, the links of robot should stretch to fit into the diameter of the pipe by using the sliding mechanism. Based on the conceptual design using TRIZ, we will set up the initial design of the robot in collaboration with a field engineer of Robot Valley, Inc. in Korea. For the optimal design of in-pipe cleaning robot, the maximum impulsive force of collision between the robot and the inner face of pipe is simulated by using RecurDyn(R) when the link of sliding mechanism is stretched to fit into the 400 mm diameter of the pipe. The stresses exerted on the 6 links of sliding mechanism by the maximum impulsive force will be simulated by using ANSYS$^{(R)}$ Workbench based on the Design Of Experiment(in short DOE). Finally the optimal dimensions including thicknesses of 4 links will be decided in order to have the best safety factor as 2 in this paper as well as having the minimum mass of 4 links. It will be verified that the optimal design of 4 links has the best safety factor close to 2 as well as having the minimum mass of 4 links, compared with the initial design performed by the expert of Robot Valley, Inc. In addition, the prototype of in-pipe cleaning robot will be stated with further research.

• Molecules and Cells
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• v.28 no.3
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• pp.189-194
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• 2009

The modulating effect of IGF-I on the regulation of AR gene expression and activation in skeletal muscle cells remains poorly understood. In this study, the effects of IGF-I treatment on AR induction and activation in the absence of AR ligands were examined. Differentiating C2C12 cells were treated with different concentrations (0-250 ng/ml) of IGF-I or for various periods of time (0-60 min) of 250 ng/ml IGF-I. Treatment of C2C12 cells with IGF-I resulted in a dose- and time-dependent increase in total AR and phosphorylated AR (Ser 213). IGF-I treatment also led to significantly increased AR mRNA expression when compared with the control. The levels of skeletal ${\alpha}-actin$ and myogenin mRNA, known target genes of AR, were also significantly upregulated after 5 or 10 min of treatment with IGF-I. Confocal images revealed that IGF-I stimulated nuclear localization of AR in the absence of ligands. In addition, an electrophoretic mobility shift assay indicated that IGF-I stimulated the AR DNA binding activity in a time-dependent manner. The present results suggest that IGF-I stimulates the expression and activation of AR by ligand-independent mechanism in differentiating C2C12 mouse skeletal muscle cells.

• Korean Journal of Plant Resources
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• v.32 no.6
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• pp.669-676
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• 2019

Zanthoxylum piperitum D.C. (ZP) peels has been used as a natural spice and herb medicine for hypertension reduction, for strokes, and for its anti-bacterial and anti-oxidant activity. However, the anti-inflammatory mechanisms employed by ZP have yet to be completely understood. In this study, we elucidate the anti-inflammatory mechanism of ZP in lipopolysaccharide (LPS)-induced RAW264.7 cells. We evaluated the effects of ZP in LPS-induced levels of inflammatory cytokines, prostaglandin E₂ (PGE₂), and caspase-1 using ELISA. The expression levels of inflammatory-related genes, including cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS), were assayed by Western blot analysis. We elucidated the effect of ZP on nuclear factor (NF)-κB activation by means of a luciferase activity assay. The findings of this study demonstrated that ZP inhibited the production of inflammatory cytokine and PGE₂ and inhibited the increased levels of COX-2 and iNOS caused by LPS. Additionally, we showed that the anti-inflammatory effect of ZP arises by suppressing the activation of NF-κB and caspase-1 in LPS- induced RAW264.7 cells. These results provide novel insights into the pharmacological actions of ZP as a potential candidate for development of new drugs to treat inflammatory diseases.

• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.395-412
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• 1997

Mammalian eggs are ovulated arrested at meiotic metaphase II until fertilization. Generally in mammals, fertilization results in a series of intracellular calcium oscillations that are mediated by inositol triphosphate (IP$^3$) or cyclic adenosine diphosphoribose (cADPr). The high levels of maturation promotion factor (MPF) within the cell decrease, pronuclei form, the cytoskeleton is reorganized and proteins are post-translationally modified. If all is normal, the newly formed embryo initiates the developmental program specific to that species. Artificial methods of producing these effects in pig oocytes are discussed. One potential mechanism mediated via a signal transduction pathway is present in pig oocytes. Stimulation of this pathway leads to the early events following fertilization, and electrical stimulation leads to apparently normal de v velopment to day 12. Further studies are needed to determine which mechanism(s) the sperm uses to initiate development.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.639-648
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• 2006

A shear experiment of one-way monotonic loading was carried out with the shear span ratio as the main experimental variable for reinforced concrete beam. Using the finite element analysis as the experimental analysis tool and the analysis method to compute the shear resistance of small shear span ratio, a new macro-model composed of crooked main strut and sub strut is proposed in consideration of the effect of bond action between re-bar and concrete based on the experimental result. The experimental finding affirmed the validity of the proposed macro-model when the shear span ratio was at or below 0.75 and confirmed that the experimental result was the most consistent with the computed analysis result when the effective factor of concrete compressive strength was set at 0.75.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.258-265
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• 2001

Turbine blade is subject to force of three type ; torsional force by torsion-mount, centrifugal force by rotation of rotor and cyclic bending force by steam pressure. Cyclic bending force of them is main factor on fatigue fracture. In the X-ray diffraction method, the change in the values related to plastic deformation and residual stress near the fracture surface mat be determined, and information of internal structure of material can be obtained. Therefore, to find a fracture mechanism of torsion-mounted blade in nuclear plant, based on the information from the fracture surface obtained by fatigue test, the correlation of X-ray parameter and fracture mechanics parameter was determined, and then the load applied to actual broken turbine blade parts was predicted. Failure analysis is performed by finite element method and Goodman diagram on torsion-mounted blade.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.6 s.249
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• pp.560-567
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• 2006

Although various conjectures have been proposed to explain abnormal increase in thermal conductivity of nanofluids, the detailed mechanism could not be understood and explained yet. The main reason is primarily due to the lack of knowledge on the most fundamental factor governing the mechanisms such as Brownian motion, liquid layering, phonon transport, surface chemical effects and agglomeration. By applying surface complexation model for the measurement data of hydrodynamic size, zeta potential, and thermal conductivity, we have shown that sulfate charge state is mainly responsible for the increase in the present condition and may be the factor incorporating all the mechanisms as well. Moreover, we propose a new model including concepts of fractal and interfacial layer. The properties such as thickness and thermal conductivity of the layer are estimated from the surface charge states and the concept of electrical double layer. With this, we could demonstrate the pH dependences of the layer properties and eventually of the effective thermal conductivity of the nanofluid.