• Journal of the Korean Institute of Gas
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• v.19 no.3
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• pp.9-17
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• 2015

Almost all of the natural gas consumed in South Korea is compressed into very high pressure for the transportation through the underground pipelines, then reduced in pressure regulation stations before delivery to the consumer. For pressure reduction, expansion valves have been used due to the simple and effective installation, but recover none of the energy in the gas during compression. Hence, turbo-expanders are proposed instead of the valves to accomplish the same pressure letdown function and recover some of the compression energy in the form of shaft work converting into electric powers. Here we have theoretically calculated the electric powers at the pressure reduction from 68.7 bar to 23 bar (which are the average values taken at the inlet and outlet points of the expansion valve in medium-pressure regulation stations) according to the inlet conditions of temperature and flow rate. The natural gas is considered as two cases of a pure methane and the mixture of hydrocarbons with a very small amount of nitrogen, and the Peng-Robinson equation of state is employed for the calculation of required thermodynamic properties. The electric energy is recovered as much as 1596 MW(methane) and 1567 MW(mixture) based on the total supply of natural gas in 2013.

• Biomolecules & Therapeutics
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• v.28 no.3
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• pp.259-266
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• 2020

The present research work primarily investigated whether spinosin has the potential of improving the pathogenesis of Alzheimer's disease (AD) driven by β-amyloid (Aβ) overproduction through impacting the procession of amyloid precursor protein (APP). Wild type mouse Neuro-2a cells (N2a/WT) and N2a stably expressing human APP695 (N2a/APP695) cells were treated with spinosin for 24 h. The levels of APP protein and secreted enzymes closely related to APP procession were examined by western blot analysis. Oxidative stress related proteins, such as nuclear factor-erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) were detected by immunofluorescence assay and western blot analysis, respectively. The intracellular reactive oxygen species (ROS) level was analyzed by flow cytometry, the levels of Aβ_1-42 were determined by ELISA kit, and Thioflavin T (ThT) assay was used to detect the effect of spinosin on Aβ_1-42 aggregation. The results showed that ROS induced the expression of ADAM10 and reduced the expression of BACE1, while spinosin inhibited ROS production by activating Nrf2 and up-regulating the expression of HO-1. Additionally, spinosin reduced Aβ_1-42 production by impacting the procession of APP. In addition, spinosin inhibited the aggregation of Aβ_1-42. In conclusion, spinosin reduced Aβ_1-42 production by activating the Nrf2/HO-1 pathway in N2a/WT and N2a/APP695 cells. Therefore, spinosin is expected to be a promising treatment of AD.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.65-75
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• 2006

Transparency on the Total System Performance Assessment (TSPA) is the key issue to enhance the public acceptance for a radioactive repository. To approve it, all performances on TSPA through Quality Assurance is necessary. The integrated Cyber R&D Platform is developed by KAERI using the T2R3 principles applicable for five major steps : planning, research work, documentation, and internal & external audits in R&D's. The proposed system is implemented in the web-based system so that all participants in TSPA are able to access the system. It is composed of three sub-systems; FEAS (FEp to Assessment through Scenario development) showing systematic approach from the FEPs to Assessment methods flow chart, PAID (Performance Assessment Input Databases) being designed to easily search and review field data for TSPA and QA system containing the administrative system for QA on five key steps in R&D's in addition to approval and disapproval processes, corrective actions, and permanent record keeping. All information being recorded in QA system through T2R3 principles is integrated into Cyber R&D Platform so that every data in the system can be checked whenever necessary. Throughout the next phase R&D, Cyber R&D Platform will be connected with the assessment tool for TSPA so that it will be expected to search the whole information in one unified system.

• Journal of Astronomy and Space Sciences
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• v.28 no.3
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• pp.163-172
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• 2011

An intensive analysis of 185 timings of WZ Cep, including our new three timings, was made to understand the dynamical picture of this active W UMa-type binary. It was found that the orbital period of the system has complexly varied in two cyclical components superposed on a secularly downward parabola over about 80y. The downward parabola, corresponding to a secular period decrease of $-9.{^d}97{\times}10^{-8}y^{-1}$, is most probably produced by the action of both angular momentum loss (AML) due to magnetic braking and mass-transfer from the massive primary component to the secondary. The period decrease rate of $-6.^{d}72{\times}10^{-8}y^{-1}$ due to AML contributes about 67% to the observed period decrease. The mass flow of about $5.16{\times}10^{-8}M_{\odot}y^{-1}$ from the primary to the secondary results the remaining 33% period decrease. Two cyclical components have an $11.^{y}8$ period with amplitude of $0.^{d}0054$ and a $41.^{y}3$ period with amplitude of $0.^{d}0178$. It is very interesting that there seems to be exactly in a commensurable 7:2 relation between their mean motions. As the possible causes, two rival interpretations (i.e., light-time effects (LTE) by additional bodies and the Applegate model) were considered. In the LTE interpretation, the minimum masses of $0.30M_{\odot}$ for the shorter period and $0.49M_{\odot}$ for the longer one were calculated. Their contributions to the total light were at most within 2%, if they were assumed to be main-sequence stars. If the LTE explanation is true for the WZ Cep system, the 7:2 relation found between their mean motions would be interpreted as a stable 7:2 orbit resonance produced by a long-term gravitational interaction between two tertiary bodies. In the Applegate model interpretation, the deduced model parameters indicate that the mechanism could work only in the primary star for both of the two period modulations, but could not in the secondary. However, we couldn't find any meaningful relation between the light variation and the period variability from the historical light curve data. At present, we prefer the interpretation of the mechanical perturbation from the third and fourth stars as the possible cause of two cycling period changes.

• Journal of Food Hygiene and Safety
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• v.18 no.4
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• pp.202-210
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• 2003

This study aims at making a HACCP(Hazard Analysis Critical Control Point)plan to be applied to soybean curd and verifing its effectiveness. First, we develped a general model of HACCP according to the guidelines of Codex (FAO/WHO). And we applied the model to 4 soybean curd workshops for 3 months. The HACCP model is composed of these procedures; HACCP team organization, production description, work flow chart, hazatd analysis, CCP (critical control point) decision, CL (critical limit) establishment, monitoring method decision, correction, verification and documentation. CCP were selection procedure and refrigeration procedure in non-wrapped soybean curd. CCP were selection procedure, heat-sterilizing and refrigeration in wrapped soybean curd. The result of bacterial experiment after apling the model for 3 months, the bacterial numbers of soybean curd box, wrapper, and soybean curd production were lower after appling than before appling, the model. We could verify that the appications of the HACCP model were effective to the soybean curd workshops.

• Journal of the Korean Institute of Gas
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• v.24 no.3
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• pp.33-39
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• 2020

In general, in a batch reaction process in which products are made using flammable liquids, splash filling is used to clean the walls of the reactor by spraying flammable liquids, which are raw materials used for product, during cleaning of the reactor after work. During this process, mist of flammable liquid is generated, the lower limit of explosion is lowered, and fire·explosion may occur due to discharges caused by various types of complex charges, such as flow charge, collision charge, and ejection charge. Therefore, based on the recent accident case, to identify the risk when working in the form of splash filling with toluene in a batch process and perform an explosion impact analysis using the TNT equivalent method After that, we will analyze the accident results and suggest preventive measures such as constant purge system, improvement of cleaning method, and use of tantalum to prevent such accident.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.58-65
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• 2020

3D Models of offshore plant piping materials designed by 3D CAD systems are provided to the production processes in the form of 2D piping drawings and 2D piping installation drawings. In addition to the standard engineering information, the purchasing, procurement, manufacturing, installation, and inspection of raw materials are managed systematically in an integrated process control system. The existing integrated process management system can help reduce the processing time by managing the flow and progress of resources systematically, but it does not include 3D design model information. Hence, it is difficult to understand complicated pipe structures before installing the pipe. In addition, when design changes or immediate design modifications are required, it is difficult to find related data or exchange information quickly with each other. To solve this problem, an offshore plant-piping process-monitoring system was developed based on a 3D model. The 3D model-based piping monitoring system is based on Visual Studio 2017 C# and UNITY3D so that the piping-process work information can be linked to the 3D CAD model in real time. In addition, the 3D model could check the progress of the pipe installation process, such as block, size, and material, and the progress of functional inspection items, such as cleaning, hydraulic inspection, and pneumatic inspection.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.517-526
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• 2013

Lifelong education promotion business to be the first to promote lifelong education promotion accountable to the governor of the city, the Lifelong Education Act Amendment (2007.12) emphasis on the research area 6 Lifelong Education and Lifelong Education Institute is established if analyzes what Gyeongsangnam-do lifetime policy implications for the promotion of education and implications are derived(through AHP). The results were as follows: occupational skill enhancement education (0.335) as the priority section. The development of life education policy (0.238) is the primary work process that must be initiated for the Gyeongnam life education promotion policy appropriate for the region's situation. This was followed by the development and distribution of life education program (0.148), construction of a connective system between life education organizations within the province (0.139) Raised the need to promote lifelong Education strategies, five core strategic industry linkages through regional industrial policy to keep pace with the flow of business for the Advancement of Education for the development and activation of Gyeongsangnam-do in a lifetime.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1292-1297
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• 2005

The use of ozone in water and wastewater treatment systems has been known to be a process that is limited by mass transfer. The most effective way to overcome this limitation is to increase the interfacial area available for mass transfer by decreasing the size of the ozone gas bubbles that are dispersed in solution. Electrostatic spraying(ES) of ozone into water was investigated in this work as a method of increasing the rate of mass transfer of ozone into a solution and thereby increasing the rate of phenol oxidation. Results were obtained for ES at input power levels ranging from 0 to 4 kV and compared with two different pore-size bubble diffusers($10{\sim}15{\mu}m$ and $40{\sim}60{\mu}m$). It was determined that the rate of mass transfer could be increased by as much as 40% when the applied voltage was increased from 0 to 4 kV as a result of the smaller bubbles generated by ES. In addition, ES was shown to be more effective than the medium-pore-size($10{\sim}15{\mu}m$) bubble diffuser and the best results were achieved at low gas flow rates.

• Analytical Science and Technology
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• v.9 no.2
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• pp.179-191
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• 1996

In order to understand the high temperature deformation behavior of superalloy 718, a rotating grade 718 alloy has been compression tested to about 0.7 upset ratio at $927{\sim}1066^{\circ}C$ temperature range and $5{\times}10^{-4}{\sim}5{\times}10^0sec^{-1}$ strain rate. The maximum flow stress was increased with increasing strain rate, and similar behavior was observed with decreasing temperature. At low temperature and high strain rates other than $5{\times}10^{-1}sec^{-1}$, strain softening was occurred mainly by dynamic recovery and deformation twinning processes, while at high temperature and low strain rates strain softening was offseted by dynamic recrystallization. At $5{\times}10^{-1}sec^{-1}$, strain hardening was occurred due to work hardening of the dynamic recrystallized grains. Strain rate sensitivity, m, was varied with strain rates. In the case of lower strain rate tests, m was measured as 0.3 and it was observed that the deformation was mainly controlled by dynamic recrystallization. At higher strain rate, m was lowered to 0.1 and the deformation was controlled by the dynamic recovery and the deformation twinning processes.