• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.59-67
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• 2018

A xylanolytic and cellulolytic anaerobic bacterium strain CtC72 was isolated from cattle rumen liquor. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain CtC72 shared only 97.78% homology with its nearest phylogenetic affiliate Actinomyces ruminicola, showing its novelty. The strain could grow on medium containing xylan, carboxymethyl cellulose and avicel producing $CO_2$, acetate, and ethanol as major fermentation products. The whole genome analysis of the strain CtC72 exhibited a broad range of carbohydrate-active enzymes required for the breakdown and utilization of lignocellulosic biomass. Genes related to the production of ethanol and stress tolerance were also detected. Further there were several unique genes in CtC72 for chitin degradation, pectin utilization, sugar utilization, and stress response in comparison with Actinomyces ruminicola. The results show that the strain CtC72, a putative novel bacterium can be used for lignocellulosic biomass based biotechnological applications.

• Interaction and multiscale mechanics
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• v.4 no.3
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• pp.187-206
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• 2011

Accurate estimations of pre-failure deformations and post-failure responses of geostructures require that the simulation tool possesses at least three main ingredients: 1) a constitutive model that is able to describe the macroscopic stress-strain-strength behavior of soils subjected to complex stress/strain paths over a wide range of confining pressures and densities, 2) an embedded length scale that accounts for the intricate physical phenomena that occur at the grain size scale in the soil, and 3) a computational platform that allows the analysis to be carried out beyond the development of an initially "contained" failure zone in the soil. In this paper, a two-scale micropolar plasticity model will be used to incorporate all these ingredients. The model is implemented in a finite element platform that is based on the mechanics of micropolar continua. Appropriate finite elements are developed to couple displacement, micro-rotations, and pore-water pressure in form of $u_n-{\phi}_m$ and $u_n-p_m-{\phi}_m$ (n > m) elements for analysis of dry and saturated soils. Performance of the model is assessed in a biaxial compression test on a slightly heterogeneous specimen of sand. The role of micropolar component of the model on capturing the post-failure response of the soil is demonstrated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.839-845
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• 2007

In this paper, a polishing pad has been analyzed in detail, to understand surface phenomena of polishing process. The polishing pad plays a key role in polishing process and is one of the important layer in polishing process, because it is a reaction layer of polishing[1]. Pad surface physical property is also ruled by pad profile. The profile and roughness of pad is controlled by different types of conditioning tool. Conditioning tool add mechanical force to pad, and make some roughness and profile. Formed pad surface will affect on polishing performance such as RR (Removal Rate) and uniformity in CMP Pad surface condition is changed by conditioning tool and dummy run and is stable at final. And this research, we want to reduce break-in and dummy polishing process by analysis of pad surface and artificial machining to make stable pad surface. The surface treatment or machining enables to control the surface of polishing pad. Therefore, this research intends to verify the effect of the buffing process on pad surface through analysis of the removal rate, friction force and temperature. In this research, urethane polishing pad which is named IC pad(Nitta-Haas Inc.) and has micro pore structure, is studied because, this type of pad is most conventional type.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.713-719
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• 2005

SPME (Soild phase microextraction) has been used in the analysis of many volatile organic compounds, such as geosmin and 2-methylisoborneol (2-MIB), trihalomethanes (THMs) in drinking water. SPME fiber is characterized by high adsorption capacity (DVB/CAR/PDMS, DVB/PDMS etc.). Although the highly active adsorption capacities of the SPME fiber are often to the chemical functional group, surface properties play a significant role in determining the surface adsorption capacities. The objectives of this study were to evaluate effect of residual chlorine on analysis of geosmin and 2-MIB. Image taken by SEM before preloaded with chlorine, the surface and porous media was almost perfect spherical shape and no clogging of pores. However, after preloaded with chlorine the surface was aggregated and pore was blocked. The recovery rate of geosmin and 2-MIB coexisting with chlorine was reduced by 35 to 62%. The recovery rate with preloaded with chlorine was reduced by 25 to 43%. The lower concentration of geosmin and 2-MIB and the higher concentration of chlorine existed in water, the lower the recovery rate was.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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• pp.609-615
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• 2015

This study was carried out for characterization of MIO synthesized in our laboratory by co-precipitation method and applied isotherm and kinetic models for adsorption properties. XRD analysis were conducted to find crystal structure of synthesized MIO. Further SEM and XPS analysis was performed before and after phosphate adsorption, and BET analysis for surface characterization. Phosphate stock solution was prepared by KH2PO4 for characterization of phosphate adsorption, and batch experiment was conducted using 50 ml conical tube. Langmuir and Freundlich models were applied based on adsorption equilibrium test of MIO by initial phosphate solution. Pseudo first order and pseudo second order models were applied for interpretation of kinetic model by temperature. Surface area and pore size of MIO were found $89.6m^2/g$ and 16 nm respectively. And, the determination coefficient ($R^2$) value of Langmuir model was 0.9779, which was comparatively higher than that of Freundlich isotherm model 0.9340.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.39-46
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• 2005

A series of numerical analyses on soft clay ground improved by plastic board drain(PBD) were carried out, in order to investigate the consolidation behavior considering viscosity of the improved ground. The applicability of numerical analyses, in which an elasto-viscoplastic three-dimensional consolidation finite element method is applied in this study, was confirmed through comparison between experimental and analytical results. As the analytical results, consolidation behavior of both settlement and excess pore pressure and effective stress in clay were elucidated. Then secondary consolidation characteristics of improved ground were estimated through compare with results of typical one-dimensional consolidation analysis.

• Smart Structures and Systems
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• v.6 no.3
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• pp.239-262
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• 2010

Tube Lines has carried out a "knowledge and investigation programme" on the deep tube tunnels comprising the Jubilee, Northern and Piccadilly lines, as required by the PPP contract with London Underground. Many of the tunnels have been in use for over 100 years, so this assessment was considered essential to the future safe functioning of the system. This programme has involved a number of generic investigations which guide the assessment methodology and the analysis of some 5,000 individual structures. A significant amount of investigation has been carried out, including ultrasonic thickness measurement, detection of brickwork laminations using radar, stress measurement using magnetic techniques, determination of soil parameters using CPT, pressuremeter and laboratory testing, installation of piezometers, material and tunnel segment testing, and trialling of remote photographic techniques for inspection of large tunnels and shafts. Vibrating wire, potentiometer, electro level, optical and fibre-optic monitoring has been used, and laser measurement and laser scanning has been employed to measure tunnel circularity. It is considered that there is scope for considerable improvements in non-destructive testing technology for structural assessment in particular, and some ideas are offered as a "wish-list". Assessment reports have now been produced for all assets forming Tube Lines' deep tube tunnel network. For assets which are non-compliant with London Underground standards, the risk to the operating railway has to be maintained as low as reasonably practicable (ALARP) using enhanced inspection and monitoring, or repair where required. Monitoring techniques have developed greatly during recent years and further advances will continue to support the economic whole life asset management of infrastructure networks.

• Geomechanics and Engineering
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• v.1 no.1
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• pp.85-96
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• 2009

The radius and coordinate of sliding circle are taken as searching variables in slope stability analysis. Genetic algorithm is applied for searching for critical factor of safety. In order to search for critical factor of safety in slope stability analysis efficiently and in a robust manner, some improvements for simple genetic algorithm are proposed. Taking the advantages of efficiency of neighbor-search of the simulated annealing and the robustness of genetic algorithm, a hybrid optimization method is presented. The numerical computation shows that the procedure can determine the minimal factor of safety and be applied to slopes with any geometry, layering, pore pressure and external load distribution. The comparisons demonstrate that the genetic algorithm provides a same solution when compared with elasto-plastic finite element program.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.603-608
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• 2004

The paper analyzes a scheme of decontamination of radionuclides from concrete structures, in which rapid microwave heating is used to spall off a thin contaminated surface layer. The analysis is split in two parts: (1) The hygrothermal part of the problem, which consists in calculating the evolution of the temperature and pore pressure fields, and (2) the fracturing part, which consists in predicting the stresses, deformations and fracturing. The rate of the distributed source of heat due to microwaves in concrete is calculated on the basis of the standing wave normally incident to the concrete wall with averaging over both the time period and the wavelength because of the very short time period of microwaves compared to the period of temperature waves and the heterogeneity of concrete. The reinforcing bars parallel to the surface arc treated as a smeared steel layer. The microplane model M4 is used as the constitutive model for nonlinear deformation and distributed fracturing of concrete. The aim of this study is to determine the required microwave power and predict whether and when the contaminated surface layer of concrete spalls off. The effects of wall thickness, reinforcing bars, microwave frequencies and power are studied numerically. As a byproduct of this analysis, the mechanism of spalling of rapidly heated concrete is clarified.

• Elastomers and Composites
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• v.30 no.3
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• pp.229-234
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• 1995

Membrane process has been applied widely to petroleum chemistry, fine chemistry, polymer, electronics, food, bioprocessing, and wastewater treatment process. Membrane process has advantage that there's no phase change through separation, energy consumption is smaller than other separation processes. And equipment investment and operation cost are inxpensive too. We prepared the silicone rubber membrane and then separated the heavy metal ion from wastewater. Silicone rubber membrane was prepared using a superitical fluid process and heavy metal ions were separated from the chromium nitrate, ferric sulfate, cupric sulfate, nickel sulfate aqueous solution. The pressure difference between top and bottom of separation apparatus was preserved by vacuum pump, and the removal amount of heavy metal at each separation step were analyzed by instrumental analysis, AAS. The surface and pore of silicone rubber membrane was investigated using SEM, and the capability of wastewater treatment using a silicone rubber membrane was proposed as calculated removal rate of heavy metal after comparing removal amount of heavy metal to amount of heavy metal in mother solution by AAS analysis.