• Wind and Structures
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• v.38 no.5
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• pp.399-410
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• 2024

Long-span suspension bridges located in typhoon-prone regions face significant risks of flutter instability, particularly in girder erection. Despite the implementation of aerodynamic countermeasures designed for the service stage, the flutter stability of bridge in girder erection may not meet the required standards. Nowadays, the double-deck truss girder is increasingly common in practical engineering which exhibits different performance from the single-deck truss girder. To gain insights into the flutter performance of this girder type and determine temporary aerodynamic countermeasures for flutter suppression in girder erection, wind tunnel tests were conducted. The effects of affiliated members on the flutter performance were first examined. Subsequently, different aerodynamic countermeasures were designed and their effectiveness was tested. The results indicate that the stabilizers above and below the upper and lower decks are the most effective for the flutter stability of bridge at positive and negative angles of attack, respectively. The higher the stabilizers are, the better the effect on flutter suppression achieves. Considering the feasibility in practical engineering, a temporary stabilizer above the upper deck was considered. It is expected that the results could provide references for the aerodynamic design of double-deck truss girder during erection.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.63-75
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• 2010

There are several remediation technologies for heavy metal contaminated soils but increasing cost limits the application of the technology if the contaminated area is large. Therefore, stabilization, which blocks the release of heavy metals or makes slow the release, is one of the applicable technology for the heavy metal contaminated soil. Current study is an applicability test for a smelter area with various stabilizer such as magnetite, hematite, zeolite-A, zeolite-X, zeolite-Y, zinc oxide, calcium oxide, carbon trioxide, manganese oxide, manganese dioxide, fish bone, sodium phosphate. The soil contaminated with arsenic, lead, copper, nickel, and zinc could not be stabilized only one stabilizer which is known to have stability for certain metal. Many of the stabilizer works for a few metal but not all of the heavy metal. In several cases, stabilizers increase the release of the other metals while they stabilize some metals. In general, the stabilizing efficiency was increased with time. For Ni, Pb, calcium oxide, carbon trioxide, manganese oxide had good stabilizing effect in water extractable portion. For Cu, manganese oxide, zeolite showed good results especially in the exchangeable portion of the sequential extraction. For As, magnetite had good ability but most of the metal oxide which showed good result for other heavy metals increased with the release of As. Current study suggest that multiple stabilizers are needed for the contaminated soil and dose of the stabilizer and stabilizing time should be carefully considered for the soil contaminated with various metals.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.379-382
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• 1991

The dynamic characteristics and mathematical models of the KEPCO's generator control systems have been derived by on-line tests. Measuring the responses for small disturbances in the inputs, the parameters of governing systems, excitation systems, and power system stabilizers have been determined. An overview of the field tests, parameter identification, and model verification is presented.

• Korean Journal of Microbiology
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• v.19 no.4
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• pp.186-191
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• 1981

Protoplast production from Trichoderma koningii ATCC 26113 was investigated for the purpose of doing basic and applied researches by protoplast fusion of the cellulolytic filamentous fungus. High yields of protoplast were obtained by using the 18hr. old mycelia treated with the lytic enzyme Driselase of Kyowa Fermentation Co., Japan, in 0.6M $MgSO_4\;or\;(NH_4)_2SO_4$ as osmotic stabilizers. The optimum temeprature of mycelial digestion was about $28^{\circ}C$ and the number of protoplast increased rapidly after 3hr. digestion. Protoplasts produced at different periods showed distinct morphological heterogeneities in the whole size and the size of vacuole.

• Polymer(Korea)
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• v.39 no.1
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• pp.78-87
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• 2015

With aiming to prepare microcapsules having a particle size of $30-50{\mu}m$, thermally expandable capsules with relatively uniform particle sizes consisting of a n-octane/poly(acrylonitrile-co-methyl methacrylate) core/shell structure were synthesized using SPG membrane emulsification and suspension polymerization. Four steric stabilizers and five crosslinking agents were employed. When poly(vinyl alcohol) as a stabilizer was used, the prepared capsules showed a smooth and regular morphology and the liquid hydrocarbon (n-octane) was well encapsulated in the core. When 1,4-butnaediol methacrylate (BDDMA) was used as a crosslinker, the uniform capsules with the average diameter of $36.8{\mu}m$ were synthesized. The capsules prepared with 0.05 mol% BDDMA showed the best encapsulation efficiency.

• Journal of the Korean Society of Food Culture
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• v.18 no.5
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• pp.475-482
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• 2003

The effects of selected stabilizers and sugars on color deterioration of anthocyanin in Schizandra fructus were examined at $100^{\circ}C$ for $120{\sim}180$ min. Among four test sugars, it was found that fructose accelerated the thermal color deterioration while maltose retarded the color deterioration by 40%. Maltodextrin and ${\gamma}$-cyclodextrin showed the highest stabilizing effect on the thermal color deterioration of crude pigment extract from Schizandra fructus(CPES) containing 2 mg% of anthocyanin. Addition of maltodextrin or ${\gamma}$-cyclodextin at 5% retarded thermal color deterioration of CPES. In gel system, 5% of maltodextrin also retarded the color deterioration by $15{\sim}20%$ during storage at $25^{\circ}C\;and\;35^{\circ}C$.

• Physical Therapy Korea
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• v.19 no.3
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• pp.105-114
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• 2012

This study was performed to compare the muscle activity of lumbar stabilizers between stoop and semi-squat lifting techniques at different lifting loads. Twenty healthy subjects (9 males, 11 females) were recruited for this study. Muscle activity of external obliques (EO), internal obliques (IO) and lumbar multifidus (LM) muscle was measured by surface electromyography during stoop and semi-squat lifting at different lifting loads (10%, 20%, and 30% of the subject's body weight). A one-way repeated measure ANOVA was applied. The results showed that EMG activity of EO was significantly increased with a load of 30% of body weight compared to 10% and 20% of body weight in both lifting techniques (p<.05). Muscle activity of LM was significantly increased in 20% compared to 10% and 30% compared to 10% of subject's body weight in stoop lifting and the muscle activity of LM was significantly increased in 20% compared to 10%, 30% compared to 20%, and 30% compared to 10% of the subject's body weight in semi-squat lifting (p<.05). However, there was no significant difference in activity of IO according to lifting loads in both lifting techniques. There were no significant differences in muscle activity of EO, IO, and LM between stoop and semi-squat technique (p>.05). Therefore, the results of this study suggested that the EO can contribute to increase the lumbar stability during stoop and semi-squat lifting at 30% of body weight rather than at lower loads, and the LM seems to act as counteractor to imposed loads during stoop and semi-squat lifting with increasing loads.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.156-163
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• 2015

The effects of low molecular-weight collagen peptides derived from porcine skin were investigated on the physicochemical and sensorial properties of chocolate ice cream. Collagen peptides less than 1 kDa in weight were obtained by sub-critical water hydrolysis at a temperature of $300^{\circ}C$ and a pressure of 80 bar. Ice cream was then prepared with gelatin powder and porcine skin hydrolysate (PSH) stabilizers mixed at seven different ratios (for a total of 0.5 wt%). There was no significant difference in color between the resulting ice cream mixtures. The increase in apparent viscosity and shear thinning of the ice cream was more moderate with PSH added than with gelatin. Moreover, the samples containing more than 0.2 wt% PSH had enhanced melting resistance, while the mixture with 0.2 wt% PSH had the lowest storage modulus at $-20^{\circ}C$ and the second highest loss modulus at 10℃, indicating that this combination of hydrocolloids leads to relatively softer and creamier chocolate ice cream. Among the seven types of ice creams tested, the mixture with 0.2 wt% PSH and 0.3 wt% gelatin had the best physicochemical properties. However, in sensory evaluations, the samples containing PSH had lower chocolate flavor scores and higher off-flavor scores than the sample prepared with just 0.5 wt% gelatin due to the strong off-flavor of PSH.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.361-368
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• 2016

A ship's rolling motion can make crew and passengers sick and/or apply forces to the structure that cause damage.. Therefore bilge keels are equipped in most ships for anti-rolling. In special cases, anti-rolling tanks (ARTs), fin stabilizers, or gyroscopes can be installed. However, ARTs require a large area to install, and fin stabilizers and gyroscopes are costly to install and expensive to operate. This paper suggests a Anti-rolling pendulum (ARP) to reduce roll motion. ARPs acts like ARTs. However, the ARP has a circular shaped guidance arc instead of the string or wire of a simple pendulum. The device suggested has about 1/ 8 the weight and 1/ 6 the volume of a ART and is more effective. This study derives the nonlinear and linear differential equations of system motion.

• Steel and Composite Structures
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• v.34 no.5
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• pp.699-713
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• 2020

The aerodynamic performance of long-span cable-stayed bridges is much dependent on its geometrical configuration and countermeasure strategies. In present study, the aerodynamic performance of three composite cable-stayed bridges with different tower configurations and passive aerodynamic countermeasure strategies is systematically investigated by conducting a series of wind tunnel tests in conjunction with theoretical analysis. The structural characteristics of three composite bridges were firstly introduced, and then their stationary aerodynamic performance and wind-vibration performance (i.e., flutter performance, VIV performance and buffeting responses) were analyzed, respectively. The results show that the bridge with three symmetric towers (i.e., Bridge I) has the lowest natural frequencies among the three bridges, while the bridge with two symmetric towers (i.e., Bridge II) has the highest natural frequencies. Furthermore, the Bridge II has better stationary aerodynamic performance compared to two other bridges due to its relatively large drag force and lift moment coefficients, and the improvement in stationary aerodynamic performance resulting from the application of different countermeasures is limited. In contrast, it demonstrates that the application of both downward vertical central stabilizers (UDVCS) and horizontal guide plates (HGP) could potentially significantly improve the flutter and vortex-induced vibration (VIV) performance of the bridge with two asymmetric towers (i.e., Bridge III), while the combination of vertical interquartile stabilizers (VIS) and airflow-depressing boards (ADB) has the capacity of improving the VIV performance of Bridge II.