• International Journal of High-Rise Buildings
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• v.2 no.3
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• pp.229-244
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• 2013

Twenty six pressure models of high rise buildings with various cross-sections including twisted models were tested in a boundary layer wind tunnel. The cross-sections were triangular, square, pentagon, hexagon, octagon, dodecagon, circular, and clover. This study investigates variations in peak pressures, and effects of various cross-sections and twist angles on peak pressures. To study the effects of various configurations and twist angles on peak pressures in detail, maximum positive and minimum negative peak pressures at each measurement point of the building for all wind directions are presented and discussed. The results show that peak pressures greatly depend on building cross-section and twist angle.

• Journal of Drive and Control
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• v.14 no.1
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• pp.14-22
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• 2017

Flow force is the additional unbalanced force acting on the valve spool by fluid flow, excluding the static pressure force that is offset on the spool land wall at the same magnitude. When designing the valve spool, it is assumed that the same average value of static pressure is applied to the inlet and outlet spool land wall in one chamber. However, the high velocity of the fluid flow by the inlet or outlet metering orifice creates unbalanced pressure distribution and generates additional force in the opposite direction to that of the solenoid attraction force. This flow force has a negative effect on the control performance of the EPPR valve, which needs to develop uniform output pressure along the entire spool control range. In this study, we developed a 3D model of the EPPR valve and conducted flow force characteristic analysis using CFD S/W (ANSYS FLUENT). The alleviated flow force model was derived by adjusting the design parameters of the spool notch.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3998-4002
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• 2012

With continuing progress of nanotechnologies and various applications of nanoparticles, one needs to develop a quick and fairly standard assessment tool to evaluate cytotoxicity of nanoparticles. However, much cytotoxicity studies on the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Here, we propose a simple screening method for the analysis of the interaction between several AgNPs (5.3 to 64 nm) and fluorescence-dye containing vesicles ($12{\mu}m$) acting as a biomimetic cell-membrane. Fluorescence-dye containing vesicle was prepared using a fluorescence probe (1,6-diphenyl-1,3,5-hexatryene), which was intercalated into the lipid bilayer due to their hydrophobicity. Zeta potential of all materials except for bare-AgNPs (+32.8 mV) was negative (-26 to -54 mV). The morphological change (i.e., rupture and fusion of vesicle, and release of dye) after mixing of the vesicle and AgNPs was observed by fluorescence microscopy, and fluorescence image were different with coating materials and surface charge of x-AgNPs. In the results, we found that the surface charge of nanoparticles is the key factor for vesicle rupture and fusion. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cell-membranes instead of in vitro or in vivo cytotoxicity tests.

• Wind and Structures
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• v.11 no.1
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• pp.1-18
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• 2008

Interference effects in five square tall buildings arranged in an L- or T-shaped pattern are investigated in the wind tunnel. Mean and fluctuating shear forces, overturning moments and torsional moment are measured on each building with a force balance mounted at its base. Results are obtained at two values of clear separation between adjacent buildings, at half and a quarter building breadth. It is found that strong interference effect exists on all member buildings, resulting in significant modifications of wind loads as compared with the isolated single building case. Sheltering effect is observed on wind loads acting along the direction of an arm of the "L" or "T" on the inner buildings. However, increase in these wind loads from the isolated single building case is found on the most upwind edge building in the arm when wind blows at a slight oblique angle to the arm. The corner formed by two arms of buildings results in some wind catchment effect leading to increased wind pressure on windward building faces. Interesting interference phenomena such as negative drag force are reported. Interference effects on wind load fluctuations, load spectra and dynamic building responses are also studied and discussed.

• Safety and Health at Work
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• v.10 no.2
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• pp.180-187
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• 2019

Background: There is considerable evidence that leadership influences workplace safety, but less is known about the relative importance of different leadership styles for safety. In addition, a leadership style characterized by an emphasis and a focus on promoting safety has rarely been investigated alongside other more general leadership styles. Methods: Data were collected through a survey to which 269 employees in a paper mill company responded. A regression analysis was conducted to examine the relative roles of transformational, transactional (management-by-exception active; MBEA), and safety-specific leadership for different safety behavioral outcomes (compliance behavior and safety initiative behaviors) and for minor and major injuries. Results: A safety-specific leadership contributed the most to the enhanced safety of the three different kinds of leadership. Transformational leadership did not contribute to any safety outcome over and above that of a safety-specific leadership, whereas a transactional leadership (MBEA) was associated with negative safety outcomes (fewer safety initiatives and increased minor injuries). Conclusion: The most important thing for leaders aiming at improving workplace safety is to continuously emphasize safety, both in their communication and by acting as role models. This highlights the importance for leadership training programs aiming to improve safety to actually focus on safety-promoting communication and behaviors rather than general leadership. Furthermore, an overly monitoring and controlling leadership style can be detrimental to attempts at achieving improved workplace safety.

• Journal of Korean Association for Spatial Structures
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• v.19 no.2
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• pp.83-90
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• 2019

Most of the variable shading devices are installed outdoors, so they are greatly affected by structural safety due to external climate change, wind, rain, and snow. Especially, due to strong wind such as typhoons, safety problems may occur due to the dropout of the device. Therefore, it is necessary to secure the structural safety against the wind. Therefore, it is necessary to analyze the structural behavior of the windshield to evaluate the structural safety of the variable sunshade device. In this study, we analyze the wind pressure applied to the shading material according to the change of the length of the variable shading device, and apply it to the calculation of the wind load for the structural design of the variable shading device. The CFD (Computational Fluid Dynamic) analysis of the structure of the sample was used to analyze wind pressure magnitude and distribution. In order to estimate the wind pressure, the maximum wind loads of the static and negative pressures acting on the structure were analyzed from numerical simulation results.

• Journal of Yeungnam Medical Science
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• v.38 no.1
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• pp.74-77
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• 2021

Lymphorrhea is a rare but potentially severe complication that occurs after various surgical procedures. Untreated lymphorrhea may lead to wound dehiscence, infection, and prolonged hospital stay. Currently, there is no standard effective treatment. Early management usually includes leg elevation, drainage, and pressure dressing. However, these methods are associated with prolonged recovery and high recurrence rates. We report a case of lymphorrhea from a calf wound after endoscopic great saphenous vein (GSV) harvesting for coronary artery bypass grafting (CABG). The patient presented with intractable oozing from the postoperative wound on the right calf. Lymphorrhea persisted for 6 weeks despite negative-pressure wound therapy with a long-acting somatostatin. We performed unilateral pedal lymphangiography that confirmed wound lymphorrhea, followed by glue embolization. No recurrence was observed after 8 months of follow-up. This case report demonstrates the successful use of lymphangiography with glue embolization in the control of lymphorrhea after GSV harvesting for CABG.

• Journal of Life Science
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• v.14 no.1
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• pp.154-162
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• 2004

Thrombospondin-1 (TSP-1), a negative regulator in tumor growth and angiogenesis, is cell-type specifically regulated and at transcriptional level by external stimuli. Previously, we found that phorbol 12-myristate 13-acetate (PMA) suppressed TSP-1 expression in porcine aortic endothelial (PAE) cell, but enhanced in hepatoma cell line, Hep 3B cell. A region between -767 and -723 on the tsp-1 promoter was defined as a responsive site to the suppression in PAE cell. eased on the previous results, the molecular mechanism of TSP-1 expression was determined by characterizing interactions between cis-elements and trans-factors using three overlapped oligonucleotide probes, oligo a-1 (from -767 to -738), a-2 (-759 to -730) and a-3 (-752 to -723). The results from electromobility shift assay showed that PMA-induced suppression of TSP-1 transcription in PAE cell might be caused via a negative regulator binding to the region from -752 to -730 and additionally generated by lacking two positive regulators binding to the sites from -767 to -760 and from -752 to -730. Especially, PMA enhanced the binding ability of the negative regulator to the site from -752 to -730 in PAE cell, but anti-c-Jun did not affected its binding ability.

• Journal of Biosystems Engineering
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• v.30 no.1 s.108
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• pp.45-55
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• 2005

Knowledge of the relationship between crop yield and yield-limiting factors is essential for precision farming. However, developing this knowledge is not easy because these yield-limiting factors are interrelated and affect crop yield in different ways. In this study, data for grain yield and yield-limiting factors, including crop chlorophyll content, soil chemical properties, and topography were collected for a small (0.3 ha) rice paddy field in Korea and a large (36 ha) upland corn field in the USA, and relationships were investigated with path analysis. Using this approach, the effects of limiting factors on crop yield could be separated into direct effects and indirect effects acting through other factors. Path analysis provided more insight into these complex relationships than did simple correlation or multiple linear regression analysis. Results of correlation analysis for the rice paddy field showed that EC, Ca, and $SiO_2$ had significant (P<0.1) correlations with rice yield, while pH, Ca, Mg, Na, $SiO_2,\;and\;P_2O_5$ had significant correlations with the SPAD chlorophyll reading. Path analysis provided additional information about the importance and contribution paths of soil variables to rice yield and growth. Ca had the highest direct effect (0.52) and indirect effect via Mg (-0.37) on rice yield. The indirect effect of Mg through Ca (0.51) was higher than the direct effect (-0.38). Path analysis also enabled more appropriate selection of important factors limiting crop yield by considering cause-and-effect relationships among predictor and response variables. For example, although pH showed a positive correlation (r=0.35) with SPAD readings, the correlation was mainly due to the indirect positive effects acting through Mg and $SiO_2$, while pH not only showed negative direct effects, but also negatively impacted indirect effects of other variables on SPAD readings. For the large upland Missouri corn field, two topographic factors, elevation and slope, had significant (P<0.1) direct effects on yield and highly significant (P<0.01) correlations with other limiting factors. Based on the correlation analysis alone, P and K were determined to be nutrients that would increase corn yield for this field. With the help of path analysis, however, increases in Mg could also be expected to increase corn yield in this case. In general, path analysis results were consistent with published optimum ranges of nutrients for rice and com production. We conclude that path analysis can be a useful tool to investigate interrelationships between crop yield and yield limiting factors on a site-specific basis.

• Tuberculosis and Respiratory Diseases
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• v.71 no.6
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• pp.400-407
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• 2011

Background: There were a few studies which were conducted to know about the behavior of the chronic obstructive pulmonary diseases (COPD) patients. The aims of this study was to explore the behaviour of COPD patients, such as awareness and impact of disease, the pathway of visiting doctors, and the treatment pattern and preference. Methods: A face-to-face interview of 300 subjects with COPD was conducted. Results: The most concerned symptom which made the respondents to visit the hospital was 'breathlessness' (78%). Only 58% of them knew the exact diagnosis. Seventy-three percent of them visited the hospital 'once a month' or 'once every 2 month'. They have made 12.8 prescheduled visits to the hospital in the past 1 year. Unscheduled visits and hospital stay figured to two in the past year. Only 11% of respondents felt they were currently in good health. 'Severe' and 'very severe' COPD patients perceived their health to be in a worse condition than 'mild' and 'moderate' COPD patients. When conditions worsened, 42% of patients were hospitalized. The most common prescription treatment was a fixed combination of inhaled corticosteroids and long-acting ${\beta}2$ agonists (48%), followed by a long acting anticholinergics (38%). Conclusion: Over forty percent of the patients didn't know exactly about their condition. Most of them had a negative attitude toward their current health status. Doctors need to know more about COPD patients in terms of their attitude toward the disease, impact of the disease, interaction with healthcare professionals and treatment related problems.