• Journal of the Korean Solar Energy Society
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• v.39 no.6
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• pp.93-112
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• 2019

In this paper, a very new web-based software for renewable energy system (RES) design and economic evaluation was introduced. This solution would provide the precise RES estimation service including not only photovoltaic (PV), wind turbine (WT) and fuel cell (FC) individually but also energy storage system (ESS) as combined forms with PV or WT. The three reasons why we ought to develop it are: First, the standardized tool suitable to the domestic environment for estimating power generation from RES facilities and economic evaluation is required. Secondly, the standardized tool is needed to spread domestic RES supply policy and to promote the new industry in the micro-grid field. The last, the reliability of economic evaluation should be enhanced more for new facilities. To achieve those aims, the weather database of one hundred locations have established and the RES facility database has also constructed. For the energy management, mathematical models for PV, WT, ESS and FC were developed. As a final phase, the analytical process to evaluate economics has performed with field data verification.

• Nuclear Engineering and Technology
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• v.47 no.7
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• pp.791-803
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• 2015

The effective cross sections (XSs) in the direct whole core calculation code nTRACER are evaluated by the equivalence theory-based resonance-integral-table method using the WIMS-based library as an alternative to the subgroup method. The background XSs, as well as the Dancoff correction factors, were evaluated by the enhanced neutron-current method. A method, with pointwise microscopic XSs on a union-lethargy grid, was used for the generation of resonance-interference factors (RIFs) for mixed resonant absorbers. This method was modified by the intermediate-resonance approximation by replacing the potential XSs for the non-absorbing moderator nuclides with the background XSs and neglecting the resonance-elastic scattering. The resonance-escape probability was implemented to incorporate the energy self-shielding effect in the spectrum. The XSs were improved using the proposed method as compared to the narrow resonance infinite massbased method. The RIFs were improved by 1% in $^{235}U$, 7% in $^{239}Pu$, and >2% in $^{240}Pu$. To account for thermal feedback, a new feature was incorporated with the interpolation of pre-generated RIFs at the multigroup level and the results compared with the conventional resonance-interference model. This method provided adequate results in terms of XSs and k-eff. The results were verified first by the comparison of RIFs with the exact RIFs, and then comparing the XSs with the McCARD calculations for the homogeneous configurations, with burned fuel containing a mixture of resonant nuclides at different burnups and temperatures. The RIFs and XSs for the mixture showed good agreement, which verified the accuracy of the RIF evaluation using the proposed method. The method was then verified by comparing the XSs for the virtual environment for reactor applicationbenchmark pin-cell problem, as well as the heterogeneous pin cell containing burned fuel with McCARD. The method works well for homogeneous, as well as heterogeneous configurations.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.136-146
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• 2019

A solid oxide fuel cell (SOFC) based hybrid desiccant cooling system model is developed to study the effect of fuel utilization rate of the SOFC on the reduction of energy consumption and $CO_2$ emission. The SOFC-based hybrid desiccant cooling system consists of an SOFC system and a Hybrid desiccant cooling system (HDCS). The SOFC system includes a stack and balance of plant (BOP), and HDCS. The HDCS consists of desiccant rotor, indirect evaporative cooler, electric heat pump (EHP), and heat exchangers. In this study, using energy load data of a commercial office building and SOFC-based HDCS model, the amount of ton of oil equivalent (TOE) and ton of $CO_2$ ($tCO_2$) are calculated and compared with the TOE and $tCO_2$ generation of the EHP using grid electricity.

• Clinical and Experimental Reproductive Medicine
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• v.50 no.1
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• pp.19-25
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• 2023

Objective: Sleep deprivation (SD) is a common problem in today's stressful lifestyle and have physiological consequences, including reproductive dysfunction and infertility. As an antioxidant, olive oil may be effective in reducing testicular and spermatological damage by decreasing the production of free radicals. Methods: This study investigated the effects of olive oil on sperm quality and testicular structure using stereological methods to assess rats with SD. Results: When comparing SD group to grid floor+distilled water (GR) group, we found that the sperm count and motility, as well as the percentage of slow progressive sperm was significantly lower in SD group (p<0.05), but the percentage of immotile sperm was higher (p<0.01). However, no improvement was observed in sperm count or motility after concomitant treatment of SD group with olive oil. Stereological examinations revealed no significant change in the total volumes of the seminiferous tubules, interstitial tissue, and germinal epithelium in the study groups. Conversely, the total number of testicular cell types was significantly lower in SD group than in GR group. Although the total number of Sertoli and Leydig cells was significantly higher in the S +olive oil group than in the untreated SD group, no significant difference in the total number of other testicular cell types was observed between the two groups. Conclusion: SD potentially induced structural changes in testis that affected sperm count and motility. However, olive oil only improved the total number of Sertoli and Leydig cells in the animals with SD and did not improve sperm count and motility.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.569-582
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• 2023

Lead-acid Battery is the oldest rechargeable battery system and has maintained its position in the rechargeable battery field. The battery causes thermal runaway for various reasons, which can lead to major accidents. Therefore, preventing thermal runaway is a key part of the battery management system. Recently, research is underway to categorize thermal runaway battery cells into machine learning. In this paper, we present a thermal runaway hazard cell detection and verification algorithm using DBSCAN and statistical method. An experiment was conducted to classify thermal runaway hazard cells using only the resistance values as measured by the Battery Management System (BMS). The results demonstrated the efficacy of the proposed algorithms in accurately classifying thermal runaway cells. Furthermore, the proposed algorithm was able to classify thermal runaway cells between thermal runaway hazard cells and cells containing noise. Additionally, the thermal runaway hazard cells were early detected through the optimization of DBSCAN parameters using a grid search approach.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.4
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• pp.381-392
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• 2011

Pollutant loads calculated with unit factor method can not identity seasonal variations of pollutant inputs. Estimation of pollutant loads considering rainfall runoff can overcome these limits. SCS curve number method was applied to estimate runoff of each event of Koeup watershed of Koheung estuary lake. SCS curve numbers were calculated based upon land use, soil types of the catchment using GIS. Point and nonpoint source pollutant loads were summed up for total loads estimation. Those from nonpoint source were estimated by multiplying the calculated runoff and expected mean concentrations (EMC) presented by the Minister of Environment of Korea. DEM can present three dimensional views of a terrain, identity stream networks and flow accumulation. Furthermore, it can examine accumulated pollutant loads of specific point of a catchment. Therefore, cell based pollutant load estimation was attempted using DEM. ArcView was utilized to collect, store and manipulate spatial and attribute data of pollutant sources and features of the catchment. Cell-based DEM which was established by the GRID module of ARC/INFO was employed to estimate flows and pollutant loads.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.4
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• pp.284-290
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• 2015

Road traffic noise is closely related with urban forms and urban components, such as population, building, traffic and land-use, etc. Hence, it is possible to minimize the noise exposure problem depending on how to plan new town or urban planning alteration. This paper provides ways to apply for urban planning in consideration of noise exposure through road traffic noise estimation for alteration of small-scale urban form. Spatial autoregressive model from the former study is used as statistical model for noise simulation. The simulation results by the spatial statistical model are compared with those by the engineering program-based modeling for 5 scenarios of small-scale urban form alteration. The error from the limitation of containing informations inside the grid cell and the difficulties of reflecting acoustic phenomena exists. Nevertheless, in the stage of preliminary design, the use of the statistical models that have been estimated well could be useful in time and economically.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.474-481
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• 2001

This paper addresses a numerical method for predicting transient temperature distributions in the wall of a curved pipe subjected to internally thermal stratification flow. A simple and convenient numerical method of treating the unsteady conjugate heat transfer in the non-orthogonal coordinate systems is presented. The proposed method is implemented in a finite volume thermal-hydraulic computer code based on a cell-centered, non-staggered grid arrangement, the SIMPLEC algorithm, a higher-order bounded convection scheme, and the modified version of momentum interpolation method. Calculations are performed for the transient evolution of thermal stratification in two curved pipes, where the one has thick wall and the other has so thin wall that its presence can be negligible in the heat transfer analysis. The predicted results show that the thermally stratified flow and transient conjugate heat transfer in a curved pipe with a finite wall thickness can be satisfactorily analyzed by the present numerical method, and that the neglect of wall thickness in the prediction of pipe wall temperature distributions can provide unacceptably distorted results.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.683-686
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• 2001

This paper presents a novel prototype of the utility­interactive voltage source type sinewave pulse modulated power inverter using a high-frequency flyback transformer link. The proposed power conditioner circuit for the solar photovoltaic generation and small scale fuel cell has an isolation function due to the safety of the power processing system, which is more cost effective and acceptable for the small-scale distributed renewal energy conditioning and processing systems. The discontinuous current mode(DCM) of this power processing conversion circuit is applied to implement a simple circuit topology and pulse modulated control scheme. Its operation principle is described on the basis of simulation evaluations and theoretical considerations. The simulation results obtained herein prove that the proposed inverter outputs with sinusoidal waveforms and unity power factor currents are synchronized to the main voltage in utility power source grid. In this paper, the soft switching topology of high­frequency linked sinewave pulse modulation inverter is proposed and discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.8
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• pp.1063-1071
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• 1999

Fine grid calculations are reported for the developing turbulent flow in a curved duct of square cross-section with a radius of curvature to hydraulic diameter ratio ${\delta}=Rc/D_H=3.357 $ and a bend angle of 720 deg. A sequence of modeling refinements is introduced; the replacement of wall function by a fine mesh across the sublayer and a low Reynolds number algebraic second moment closure up to the near wall sublayer in which the non-linear return to isotropy model and the cubic-quasi-isotropy model for the pressure strain are adopted; and the introduction of a multiple source model for the exact dissipation rate equation. Each refinement is shown to lead to an appreciable improvement in the agreement between measurement and computation.