• Journal of the Korean Society for Precision Engineering
• /
• v.34 no.1
• /
• pp.59-63
• /
• 2017

We present a multi-sample array device based on a pneumatic system. Solenoid valves were used to control a micro valve in a pneumatic system. The use of a compressor together with a vacuum pump ensured that one outlet could supply both compression and vacuum pressure. The multi-sample array device was fabricated using conventional photolithography and PDMS casting. The device was composed of a multiplexer, sample array, and rinsing. The multiplexer could control four sample solutions injecting into the sample array chamber. Sample solution not arrayed was removed by DI-water from the rinsing inlet. To prevent trapping of microbubbles in the channel during injection of sample solution into the device, surfactant was added in PDMS solution to serve as a hydrophilic surface treatment. As a result, the device could be used as a sample array for 64 cases, using four samples and three columns of three chambers.

• Imaging Science in Dentistry
• /
• v.53 no.2
• /
• pp.91-99
• /
• 2023

Purpose: This systematic review aimed to investigate the correlation between chronological age and dental pulp volume in cone-beam computed tomography (CBCT). Materials and Methods: The literature was searched in 4 databases(PubMed, Scopus, Web of Science, and Google Scholar). Within each study, the outcome of interest was the correlation (r) between chronological age and pulp volume. A random-effect meta-analysis was conducted. Subgroup analysis was carried out according to sex and tooth type. Results: Of 5,693 identified studies, 27 fulfilled the inclusion criteria and were selected for meta-analysis. These articles focused on single-rooted teeth (n=21), multi-rooted teeth (n=6), maxillary teeth (n=14), mandibular teeth (n=6), and maxillary and mandibular teeth (n=12). The relationship between chronological age and dental pulp volume was examined in the entire population (r= -0.67), men (r= -0.75), and women (r= -0.77) in single- and multi-rooted teeth. The results of the total population analysis showed a relatively strong negative relationship between age and pulp volume. Conclusion: This study suggested that CBCT is a reliable and repeatable tool for dental age estimation. A strong inverse relationship was observed between pulp chamber volume and age. Further studies on the correlation between chronological age and pulp volume of multi-rooted teeth may be beneficial.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.16 no.2
• /
• pp.25-33
• /
• 2012

A genetic algorithm (GA) has been employed to optimize the major design variables of the liquid rocket engine. Pressure of the main combustion chamber, nozzle expansion ratio and O/F ratio have been selected as design variables. The target engine has the open gas generator cycle using the LO2/RP-1 propellant. The gas properties of the combustion chamber have been obtained from CEA2 and the mass has been estimated using reference data. The objective function has been set as multi-objective function with the specific impulse and thrust to weight ratio using the weight method. The result shows about 4% improvement of the specific impulse and 23% increase of the thrust to weight ratio. The Pareto frontier line has been also obtained for various thrust requirements.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.51-58
• /
• 2003

A cycle simulation method is developed by coupling a commercial code, Ricardo's WAVE, with the SENKIN code from CHEMKIN packages to predict combustion characteristics of an HCCI engine. By solving detailed chemical kinetics the SENKIN code calculates the combustion products in the combustion chamber during the valve closing period, i.e. from IVC to EVO. Except the combustion chamber during the valve closing period the WAVE code solves thermodynamic status in the whole engine system. The cycle simulation of the complete engine system is made possible by exchanging the numerical solutions between the codes on the coupling positions of the intake port at IVC and of the exhaust port at EVO. This method is validated against the available experimental data from recent literatures. Auto ignition timing and cylinder pressure are well predicted for various engine operating conditions including a very high ECR rate although it shows a trend of sharp increase in cylinder pressure immediate after auto ignition. This trend is overpredicted especially for EGR cases, which may be due to the assumption of single-zone combustion model and the limit of the chemical kinetic model for the prediction of turbulent air-fuel mixing phenomena. A further work would be needed for the implementation of a multi-zone combustion model and the effect of turbulent mixing into the method.

• Journal of the Korea Convergence Society
• /
• v.11 no.10
• /
• pp.231-236
• /
• 2020

A water reforming reaction high-speed turning incinerator test facility was prepared. The reforming reaction chamber and the combustion chamber were directly connected. The incinerator and dust collecting device were integrated and made into a double bulkhead type air cooling structure. The blower is built into the dust collector to improve spatial efficiency. An axial flow type multi-stage dust collector was applied by collecting dust by using a plurality of dust collecting bins attached to the side of the dust collecting part. As a result of measuring dioxin among the exhausted gases, results below the standard value were obtained. As a result of measuring exhaust gas and heavy metals, results were obtained below the environmental standard.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.55
• /
• pp.125-154
• /
• 2012

The International Chamber of Commerce (ICC) has published revised rules of arbitration, which come into force on 1 January 2012 (the ICC Rules 2012). The ICC Rules 2012 apply to all arbitrations commenced on or after 1 January 2012, unless the parties have agreed to submit their arbitration to the rules in effect on the date of their arbitration agreement (Article 6(1)). The ICC Rules 2012 explicitly require both the arbitrators and the parties to make every effort to conduct the arbitration in an expeditious and cost-effective manner. The changes will force participants to define more aspects of their claims and outline the merits of the dispute earlier on in the process. The Rules also contain new penalties for behaving in a way that undermines the process's efficiency. The new Rules permit the tribunal, when making allocating costs, to take into account the extent to which each party has conducted the arbitration in an expeditious and cost-effective manner. Entirely new provisions relate to the emergency arbitrators, case management, and multi-party arbitrations. The ICC Rules 2012 take into account developments in arbitration practice and procedure, and in information technology, since the last revision of the rules in 1998, the aim being to provide modern and flexible procedures that promote efficiency in the arbitral process.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.127-134
• /
• 2011

A genetic algorithm (GA) has been employed to optimize the major design variables of the liquid rocket engine. Pressure of the main combustion chamber, nozzle expansion ratio and O/F ratio have been selected as design variables. The target engine has the open gas generator cycle using the LO2/RP-1 propellant. The gas properties of the combustion chamber have been obtained from CEA2 and the mass has been estimated using reference data. The objective function has been set as multi-objective function with the specific impulse and thrust to weight ratio using the weight method. The result shows about 4% improvement of the specific impulse and 23% increase of the thrust to weight ratio. The Pareto frontier line has been also obtained for various thrust requirements.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.3
• /
• pp.185-193
• /
• 2014

In this paper, we developed a 4-channel particle counter for measuring particles, temperature, humidity in production facilities of clean-room environment, and the measured data can be transmitted via bluetooth. To measure the particle size ranging 0.3um~5um, we designed optical lens, particle detection chamber and multi-channel particle detection circuit. And we also developed a FMS program for real-time monitoring of measuring data, which resulted in the stable operation.

• Applied Microscopy
• /
• v.43 no.2
• /
• pp.88-97
• /
• 2013

Technical investigation to figure out the problems arising during in-situ heating electron backscatter diffraction (EBSD) analysis inside scanning electron microscopy (SEM) was carried out. EBSD patterns were successfully acquired up to $830^{\circ}C$ without degradation of EBSD pattern quality in steels. Several technical problems such as image drift and surface microstructure pinning were taking place during in-situ experiments. Image drift problem was successfully prevented in constant current supplying mode. It was revealed that the surface pinning problem was resulted from the $TiO_2$ oxide particle formation during heating inside SEM chamber. Surface pinning phenomenon was fairly reduced by additional platinum and carbon multi-layer coating before in-situ heating experiment, furthermore was perfectly prevented by improvement of vacuum level of SEM chamber via leakage control. Plane view in-situ observation provides better understanding on the overall feature of recrystallization phenomena and cross sectional in-situ observation provides clearer understanding on the recrystallization mechanism.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.5
• /
• pp.593-602
• /
• 1999

This paper presents combustion characteristics of LPG-air mixture ignited by the plasma jet in a cylindrical vessel with constant volume, in which our focus is placed on the multi-hole plug configuration. Four types of the plug configuration depending on the number of orifice and the arranged angle are considered, along with two cases of conventional spark ignition for comparison. Not only the flame propagation is photographed at intervals, but the pressure in the combustion chamber is also recorded through the entire combustion process. The results show that the plasma jet ignition enhances the overall combustion rate remarkably in comparison to the spark ignition by generating irregular flame front and penetrating through the unburned mixture. The combustion enhancement rate agrees favorably with the available data, which supports the validity of our experiment. Synthetically estimating, the two-hole sixty-degree plug appears to be the most desirable, in that the maximum pressure as well as the combustion duration is less affected by the sub-energy level than the others. It is also deduced that there may exist an optimal plug configuration capable of rapid combustion for a specific combustion chamber.