• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.118-124
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• 2005

In this research, we examined the effect of NaCl on the growth, energy metabolism, and proton motive force of Halomonas salina, and the effect of compatible solutes on the bacterium growing in the high salinity environment. H. salina was isolated from seawater and identified by 16srDNA sequencing. The growth of H. salina was not enhanced by the addition of external compatible solutes (choline and betaine) in the high salinity environment. The resting cells of H. salina absorbed more glucose in the presence of 2.0 M NaCl than in its absence. H. salina did not grow in the medium with either KCl, RbCl, CsCl, $Na_2SO_4$, or $NaNO_3$, in place of NaCl. The optimal concentration of NaCl for the growth of H. salina ranged from 1.4 M to 2.5 M, and the growth yield was decreased in the presence of NaCl below 1.4M and above 2.5M. The activity of isocitrate dehydrogenase, pyruvate dehydrogenase, and malate dehydrogenase of H. salina was not inhibited by NaCl in in vitro test. The proton translocation of H. salina was detected in the presence of NaCl only. These results indicate that NaCl is absolutely required for the normal growth and energy metabolism of H. salina, but the bacterial growth is not enhanced by the compatible solutes added to the growth medium.

• Architectural research
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• v.19 no.4
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• pp.117-124
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• 2017

In this research, we carried out finite element analysis depends on the variations such as the strength of the main bar, concrete, shear-span ratio(a/d) and existence of shear reinforcing bar. Throughout the results of FEM analysis, we were able to figure out how each variation can effect on shear performance. As the strength of concrete increased, the maximum shear force enhancement effect of each specimen was evaluated. As a result, the shear strengthening effect was 51~97% for shear reinforced specimens, and 26~44% for non-shear reinforced specimens. As the yield strength of reinforcing bars increases, the shear reinforcement effect of the specimen the specimens without shear reinforcement were 3%~6% higher than those with shear reinforcement. Theoretical and analytical values were compared using the design equations obtained from the CEB code. Theoretical and analytical values were compared using the design equations obtained from the CEB code. As a result, the error rate was the highest at 3.64 in the S1.0-C0 series and the lowest at 1.46 in the S1.7-C1 series. Therefore, the design equation of the CEB code is estimated to underestimate the actual shear strength of deep beams that are not subjected to shear reinforcement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.171-175
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• 2001

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectrics and metal, which can apply to employed in integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of free-defects in inter level dielectrics and metal. Especially, defects like (micro-scratch) lead to severe circuit failure, and affects yield. Current conditioning method - bladder type, orbital pad motion- usually provides unsuitable pad profile during ex-situ conditioning near the end of pad life. Since much of the pad wear occurs by the mechanism of bladder type conditioning and its orbital motion without rotation, we need to implement new ex-situ conditioner which can prevent abnormal regional force on pad caused by bladder-type and also need to rotate the pad during conditioning. Another important study of ADPC is related to the orbital scratch of which source is assumed as diamond grit dropped from the strip during ex-situ conditioning. Scratch from diamond grit damaged wafer severely so usually scraped. Figure 1 shows the typical shape of scratch damaged from diamond. e suspected that intensive forces to the edge area of bladder type stripper accelerated the drop of Diamond grit during conditioning. so new designed Flat stripper was introduced.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.06a
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• pp.5-15
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• 1997

It is the objective of this study that by conducting the serni-solid extrusion using A12024, the effect of various process variables on the quality of extruded product and extrusion force is understood. The results of experiment are compared with those of finite element simulation in order to verify the effectiveness of the developed FE-simulation code. In order to simulate densification in the deformation of serni-solid material, the semi-solid material is assumed to be composed of solid region as porous skeleton following compressible visco-plastic model and liquid region following Darcy's equation for the liquid flow saturated in the interstitial space. Then the flow and deformation of the semi-solid alloy are analyzed by coupling the deformation of the porous skeleton and the flow of the eutectic liquid. It is assumed that initial solid fraction is homogeneous. Yield and plastic potential function presented by Kuhn and constitutive model developed by Gunasekera are used for solid skeleton.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.2
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• pp.63-68
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• 2008

Hard and brittle materials, such as Ni- and Ti-based alloys, glass, and ceramics, are very useful in aerospace, marine, electronics, and high-temperature applications because of their extremely versatile mechanical and chemical properties. One Ni-based alloy, Inconel 718, is a precipitation-hardenable material designed with exceptionally high yield strength, ultimate tensile strength, elastic modulus, and corrosion resistance with outstanding weldability and excellent creep-rupture properties at moderately high temperatures. However, conventional machining of this alloy presents a challenge to industry. Ultrasonic vibration cutting (UVC) has recently been used to cut this difficult-to-machine material and obtain a high quality surface finish. This paper describes an experimental study of the UVC parameters for Inconel 718, including the cutting force components, tool wear, chip formation, and surface roughness over a range of cutting conditions. A comparison was also made between conventional turning (CT) and UVC using scanning electron microscopy observations of tool wear. The tool wear measured during UVC at low cutting speeds was lower than CT. UVC resulted in better surface finishes compared to CT under the same cutting conditions. Therefore, UVC performed better than CT at low cutting speeds for all measures compared.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.1
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• pp.17-23
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• 2009

This paper proposes a new type of MR(magnetorheological) fluid based suspension system and applies it to military vehicle for vibration control. The suspension system consists of gas spring and MR damper. The nonlinear behavior of spring characteristics is evaluated with respect to the wheel travel and damping force model due to viscosity and yield stress of MR fluid is derived. Subsequently, a military vehicle of 6WD is adopted for the integration of the MR suspension system and its nonlinear dynamic model is established by considering vertical, pitch and roll motion. Then, a sky-hook controller associated with semi-active actuating condition is designed to reduce the imposed vibration. In order to demonstrate the effectiveness of the proposed MR suspension system, computer simulation is undertaken showing vibration control performance such as roll angle and pitch angle evaluated under bump and random road profiles.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1138-1144
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• 2009

This study was carried out to investigate the cooking properties and lipid oxidation stability during storage at $4{\pm}1^{\circ}C$ when the various levels (5 to 20%) of doenjang (Korean fermented soybean paste) were added to pork patties cooked by pan frying (PF) and convection oven (CO). With increasing the addition of doenjang, cooking properties of pork patties revealed the improved cooking yield, less diameter reduction, and less thickness increase. Also, the shear force, hardness, and chewiness of pork patties were reduced. The PF cooking method showed better cooking properties than CO. Lipid oxidation expressed by the thiobarbituric acid reactive substances (TBARS) values was significantly reduced by the addition of more than 5% doenjang (p<0.05). The TBARS values of cooked pork patties by PF were significantly lower than CO during the 8 days of the storage (p<0.05). The development of warmed-over flavor (WOF) in cooked pork patties was delayed as the amount of the doenjang was increased. It was suggested that the addition of doenjang and PF favorably affected the cooking properties and stability of lipid oxidation in pork patties.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.237-249
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• 2016

There are constraints on truck weight, axle configurations and size imposed by departments of transportation around the globe due to structural capacity limitations of highway pavements and bridges. In spite of that, freight movers demand some vehicles that surpass the maximum size and legal weight limits to use the transportation network. Oversized trucks serve the purpose of spreading the load on the bridge; thus, reducing the load effect on the superstructure. For such vehicles, often a quick structural analysis of the existing bridges along the traveled route is needed to ensure that the structural capacity is not exceeded. For a wide vehicle having wheel gage larger than the standard 1830 mm, the girder distribution factors in the design specifications cannot be directly used to estimate the live load in the supporting girders. In this study, a simple approach that is based on finite element analysis is developed by modifying the AASHTO LRFD's girder distribution factors for slab-on-steel-girder bridges to overcome this problem. The proposed factors allow for determining the oversized vehicle bending moment and shear force effect in the individual girders as a function of the gage width characteristics. Findings of the study showed that the relationship between the girder distribution factor and gage width is more nonlinear in shear than in flexure. The proposed factors yield reasonable results compared with the finite element analysis with adequate level of conservatism.

• Nuclear Engineering and Technology
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• v.43 no.5
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• pp.421-428
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• 2011

The out-of-pile mechanical performance and microstructure of recrystallized Zr-1.5 Nb-S alloy was investigated. The strength of the recrystallized Zr-1.5Nb-O-S alloys was observed to increase with the addition of sulfur over a wide temperature range, from room temperature up to $300^{\circ}C$. A yield drop and stress serrations due to dynamic strain were observed at room temperature and $300^{\circ}C$. Wavy and curved dislocations and loosely knit tangles were observed after strained to 0.07 at room temperature, suggesting that cross slip is easier. At $300^{\circ}C$, however, dislocations were observed to be straight and aligned along the slip plane, suggesting that cross slip is rather difficult. At $300^{\circ}C$, oxygen atoms are likely to exert a drag force on moving dislocations, intensifying the dynamic strain aging effect. Oxygen atoms segregated at partial dislocations of a screw dislocation with the edge component may hinder the cross slip, resulting in the rather straight dislocations distributed on the major slip planes. Recrystallized Zr-Nb-S alloys exhibited ductile fracture surfaces, supporting the beneficial effect of sulfur in zirconium alloys. Oxidation resistance in air was also found to be improved with the addition of sulfur in Zr-1.5 Nb-O alloys.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.43-51
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• 2015

This paper presents effect of aerodynamic loads on mooring line responses of a floating offshore wind turbine. A Matlab code based on blade element momentum (BEM) theory is developed to consider aerodynamic loads acting on NREL 5MW wind turbine. The aerodynamic loads are coupled with time-domain hydrodynamic analyses using one-way interaction scheme of the wave and wind loads. A semi-submersible floating platform which is from Offshore Code Comparison Collaborative Continuation(OC4) DeepCWind platform is used with catenary mooring lines simply composed of studless chain links. Average values of mooring peak tensions obtained from aerodynamic load consideration are significantly increased compared to those from simple wind drag force consideration. Consideration of aerodynamic loads also yield larger tension ranges which can be important factor to reduce fatigue life of the mooring lines.