• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1445-1453
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• 2013

The scale-up criterion of constant oxygen mass transfer coefficient ($k_La$) was applied for the production of itaconic acid (IA) in a 50 L pilot-scale fermentor by the fungal cells of Aspergillus terreus. Various operating conditions were examined to collect as many $k_La$ data as possible by adjusting the stirring speed and aeration rate in both 5 L and 50 L fermentor systems. In the fermentations performed with the 5 L fermentor, the highest IA production was obtained under the operating conditions of 200 rpm and 1.5 vvm. Accordingly, we intended to find out parallel agitation and aeration rates in the 50 L fermentor system, under which the $k_La$ value measured was almost identical to that ($0.02sec^{-1}$) of the 5 L system. The conditions of 180 rpm and 0.5 vvm in the 50 L system turned out to be optimal for providing almost the same volumetric amount of dissolved oxygen (DO) into the fermentor, without causing shear damage to the producing cells due to excessive agitation. Practically identical fermentation physiologies were observed in both fermentations performed under those respective operating conditions, as demonstrated by nearly the same values of volumetric ($Q_p$) and specific ($q_p$) IA production rates, IA production yield ($Y_{p/s}$), and specific growth rate (${\mu}$). Specifically, the negligible difference of the specific growth rate (${\mu}$) between the two cultures (i.e., $0.029h^{-1}$ vs. $0.031h^{-1}$) was notable, considering the fact that ${\mu}$ normally has a significant influence on $q_p$ in the biosynthesis of secondary metabolites such as itaconic acid.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.69-79
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• 2017

The purpose of this study was to investigate the effect of project selection procedures such as information provision and transparency and project application conditions such as required documents and conditions on the satisfaction of agricultural subsidy support policy and re-application intention to support pig farmers in Jeju. The results of analysis are summarized as follows. First Need to improve the satisfaction of the business selection procedure rather than to relax the business application conditions in order to improve the satisfaction of the subsidy support business. Second, Need to improve the satisfaction of the business selection procedure rather than to relax the business application conditions in order to increase the subsidy re-application intention through the income increase effect by the subsidy support project. It is shown that the efforts to improve the satisfaction of the selection process can improve the satisfaction of the subsidy support project as well as re-application intention at the same time. Therefore, It is necessary to focus on improving the satisfaction of the project selection process, such as providing information and reflecting opinions on the subsidy project.

• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.46-52
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• 2015

Pump-turbine system is widely used by the hydropower industry for stabilizing the electrical grid in the vast growing economy of most developed countries. This study only investigates the Fluid-structure Interaction (FSI) analysis of the pump-turbine system at various operating conditions. The FSI analysis can show how reliable each component of the system is by providing the engineer with a better understanding of high stress and deformation points, which could reduce the lifespan of the pump-turbine. Pump-turbine components are categorized in two parts, pressurized static parts and movable stressed parts. The fixed parts include the spiral casing, top and bottom cover, stay vane and draft tube. The movable parts include guide vanes and impeller blades. Fine hexahedral numerical grids were used for CFD calculation and fine tetrahedral grids were used for structural analysis with imported load solution mapping greater than 90 %. The maximum equivalent stress are much smaller than the material yield stress, and the maximum equivalent stress showed an increasing tendency with the varying of operating conditions from partial to excessive at both modes. In addition, the total deformation of all the operating conditions showed a small magnitude, which have quite small influence on the structural stability. It can be conjectured that this system can be safely implemented.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.207-213
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• 2022

The article reveals the problems of aesthetic education of young people as a necessary condition for the cultural development of the individual in the modern conditions of the information society. Aesthetic education should contribute to the formation of a creatively active personality. The basis of aesthetic education of young people in the modern conditions of the information society is the core of artistic culture - art as a unique form of public consciousness that contributes to the spiritual development and improvement of the inner world of a person. The main tasks of aesthetic education are highlighted. It is focused on the formation of aesthetic consciousness and aesthetic behavior of the individual. The formation of true aesthetic and spiritual values of students is impossible without a deep awareness of the national foundations of culture, which combines science (including technology), education, art, morality, way of life and worldview, and most importantly its information component - information culture. The effectiveness of aesthetic education of students largely depends on the skillful use of various methods and means by teachers. Aesthetic education of students involves a qualitative change in the level of their aesthetic culture in the modern conditions of the information society. In the era of information and computer technologies, the main Institute for aesthetic education of young people, as a necessary condition for the cultural development of the individual, is mass media. Television stands out especially because it has several information series (audio and video sequence), multiplied by the efficiency of providing information that increases several times compared to paper media, which allows you to report directly during the event.

• Korean Journal of Clinical Pharmacy
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• v.34 no.3
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• pp.194-201
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• 2024

Background: Asthma is a chronic inflammatory airway disease associated with systemic inflammation and increased prevalence of various comorbid conditions. This study investigates the prevalence of non-respiratory comorbidities among adult asthma patients in South Korea, aiming to elucidate potential correlations and impacts of asthma on overall health, thereby affecting patients' quality of life and healthcare systems. Methods: This retrospective cohort study utilized the National Health Insurance Service data (HIRA-NPS-2020) and included adults diagnosed with asthma. Non-respiratory diseases were identified using the Korean Standard Disease Classification (KCD-8) codes, with exclusions applied for other respiratory conditions. The prevalence of comorbidities was analyzed and compared between asthma and non-asthma patients, adjusting for confounders such as age, gender, and insurance status through inverse probability treatment weighting (IPTW). Results: The analysis revealed that asthma patients exhibit significantly higher rates of cardiovascular diseases, metabolic disorders, gastrointestinal conditions, and mental health issues compared to the control group. Notably, conditions such as heart failure, gastroesophageal reflux disease, and anxiety were more prevalent, with odds ratios (OR) ranging from 1.18 to 3.90. These results demonstrate a substantial burden of comorbidities associated with asthma, indicating a broad impact on health beyond the respiratory system. Conclusion: The findings highlight the systemic nature of asthma and the interconnectedness of inflammatory processes across different organ systems. This comprehensive analysis confirms previous research linking asthma with an increased risk of various non-respiratory diseases, providing insights into the multifaceted impact of asthma on patient health.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.969-975
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• 2002

Visual effects are important cues for providing occupants with virtual reality in a vehicle simulator which imitates real driving. The viewpoint of an occupant is sensitively dependent upon the occupant's posture, therefore, the total human body motion must be considered in a graphic simulator. A real-time simulation is required for the dynamic analysis of complex human body motion. This study attempts to apply a neural network to the motion analysis in various driving situations. A full car of medium-sized vehicles was selected and modeled, and then analyzed using ADAMS in such driving conditions as bump-pass and lane-change for acquiring the accelerations of chassis of the vehicle model. A hybrid III 50%ile adult male dummy model was selected and modeled in an ellipsoid model. Multibody system analysis software, MADYMO, was used in the motion analysis of an occupant model in the seated position under the acceleration field of the vehicle model. Acceleration data of the head were collected as inputs to the viewpoint movement. Based on these data, a back-propagation neural network was composed to perform the real-time analysis of occupant motions under specified driving conditions and validated output of the composed neural network with MADYMO result in arbitrary driving scenario.

• Steel and Composite Structures
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• v.25 no.3
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• pp.347-360
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• 2017

The goal of this study is to fill this apparent gap in the area about vibration analysis of multiwalled carbon nanotubes (MWCNTs) curved panels by providing 3-D vibration analysis results for functionally graded multiwalled carbon nanotubes (FG-MWCNTs) sandwich structure with power-law distribution of nanotube. The effective material properties of the FG-MWCNT structures are estimated using a modified Halpin-Tsai equation. Modified Halpin-Tsai equation was used to evaluate the Young's modulus of MWCNT/epoxy composite samples by the incorporation of an orientation as well as an exponential shape factor in the equation. The exponential shape factor modifies the Halpin-Tsai equation from expressing a straight line to a nonlinear one in the MWCNTs wt% range considered. Also, the mass density and Poisson's ratio of the MWCNT/phenolic composite are considered based on the rule of mixtures. Parametric studies are carried out to highlight the influence of MWCNT volume fraction in the thickness, different types of CNT distribution, boundary conditions and geometrical parameters on vibrational behavior of FG-MWCNT thick curved panels. Because of using two-dimensional generalized differential quadrature method, the present approach makes possible vibration analysis of cylindrical panels with two opposite axial edges simply supported and arbitrary boundary conditions including Free, Simply supported and Clamped at the curved edges. For an overall comprehension on 3-D vibration analysis of sandwich panel, some mode shape contour plots are reported in this research work.

• International Journal of Fluid Machinery and Systems
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• v.10 no.2
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• pp.164-175
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• 2017

Francis turbines are often operated over a wide load range due to high flexibility in electricity demand and penetration of other renewable energies. This has raised significant concerns about the existing designing criteria. Hydraulic turbines are not designed to withstand large dynamic pressure loadings on the stationary and rotating parts during such conditions. Previous investigations on transient operating conditions of turbine were mainly focused on the pressure fluctuations due to the rotor-stator interaction. This study characterizes the synchronous and asynchronous pressure and velocity fluctuations due to rotor-stator interaction and rotating vortex rope during load variation, i.e. best efficiency point to part load and vice versa. The measurements were performed on the Francis-99 test case. The repeatability of the measurements was estimated by providing similar movement to guide vanes twenty times for both load rejection and load acceptance operations. Synchronized two dimensional particle image velocimetry and pressure measurements were performed to investigate the dominant frequencies of fluctuations, vortex rope formation, and modes (rotating and plunging) of the rotating vortex rope. The time of appearance and disappearance of rotating and plunging modes of vortex rope was investigated simultaneously in the pressure and velocity data. The asynchronous mode was observed to dominate over the synchronous mode in both velocity and pressure measurements.

• Journal of The Korean Astronomical Society
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• v.48 no.4
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• pp.207-212
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• 2015

We introduce the Lee Sang Gak Telescope (LSGT), a remotely operated, robotic 0.43-meter telescope. The telescope was installed at the Siding Spring Observatory, Australia, in 2014 October, to secure regular and exclusive access to the dark sky and excellent atmospheric conditions in the southern hemisphere from the Seoul National University (SNU) campus. Here, we describe the LSGT system and its performance, present example images from early observations, and discuss a future plan to upgrade the system. The use of the telescope includes (i) long-term monitoring observations of nearby galaxies, active galactic nuclei, and supernovae; (ii) rapid follow-up observations of transients such as gamma-ray bursts and gravitational wave sources; and (iii) observations for educational activities at SNU. Based on observations performed so far, we find that the telescope is capable of providing images to a depth of R = 21:5 mag (point source detection) at 5-σ with 15 min total integration time under good observing conditions.

• Journal of Welding and Joining
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• v.14 no.6
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• pp.68-80
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• 1996

When a workpiece is to be arc welded around the outside corner, continuous welding without welding seam in the neighborhood of comer still remains a very difficult technique. Skilled welders weld comers by delicate“hand-eye coordination”while turning the workpiece manually, However, there is not a very clear solution to this problem in robotized arc welding process. In order to solve this problem, the coordination of a robot and a positioner with one or two axes is necessary. This paper presents a method of continuous welding around the corner of workpiece using the coordinated motion of a robot and a positioner. The positioner is either revolute jointed or prismatic jointed. In this paper, a clothoid curve is chosen for welding trajectory. The clothoid curve is excellent in connecting straight and curved weld-lines with good continuity and accommodates various welding conditions. By using this welding trajectory, the deceleration, which leads to widening of the melt and the heat affected zone, at comer area is reduced with strategic rotation of robot torch in coordination with a positioner providing smooth transition of welding torch orientation. Two types of special clothoid curves are developed for different weld slope conditions. These clothoid curves are applied to the case of linear and rotary Positioners at arc welding robot work-cell.