• KSBB Journal
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• v.22 no.2
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• pp.97-101
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• 2007

This study was performed to examine the availability of anaerobic digestion of the remainders caused by bacterial cellulose production process using food wastes. They maybe to be considered as others second pollution sources. Thus, this study was targeted to minimize content of organic material and to obtain more energy in those remnants using two-phase UASB reactor. The working volume of first hydrolysis fermentor was 35 L (total 55 L) and the second methane fermentor was 40 L (total 50 L). The organic loading rate of hydrolysis fermentor was 3 g-VS/L${\cdot}$day and 25,000 ppm of $COD_{cr}$ for methane fermentor. The hydraulic retention time was 18 days for hydrolysis reactor and 33 days for methane reactor. The hydrolysis reactor and methane reactor were performed at 35, 40$^{\circ}C$ respectively. For the efficient stable performance, the composition of organic wastes at each stage was as follow; Food waste with bacterial culture remnants (1 : 1), bacterial cellulose remnants, bacterial cellulose culture remnants with food wastes saccharified solids (1 : 1). When the anaerobic digestion was performed stably at each stage, the COD removal efficiency was 88, 90, 91 % respectively. At this time, methane production rate was 0.26, 0.34, $0.32m^3\;CH_4/kg-COD_{remove}$. As well as the values of anaerobic digestion at third stage were more higher than values of anaerobic digestion using food wastes. It is clearly to say that the food wastes zero-emission system constructed in our lab is more efficient way to treat and reclaim food wastes.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.249-258
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• 2005

A two-column six-step pressure swing adsorption(PSA) process was to study separation of hydrogen from hydrogen and methane($60_{vol}%/40_{vol}%$) binary system onto activated carbon adsorbent. The effects of the feed gas pressure, the feed flowrate and the P/F(purge to feed) ratio on the process performance were evaluated. The cyclic steady-states of PSA process were reached to after 15 cycles. $H_2$ purity increases according as the P/F ratio and pressure increase and the feed flow rate decreases; however, $H_2$ recovery shows an opposite phenomena to the purity. PSA process simulation studied to find optimum operation condition. In the results, 22 LPM feed flowrate, 11 atm adsorption pressure and 0.10 P/F ratio might be optimal values to obtain more than 75% recovery and 99% purity hydrogen. In this study was non-isothermal and non-adiabatic model considering linear driving force(LDF) model and Langmuir-Freundlich adsorption isotherm considered to compare between prediction and experimental data.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.4
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• pp.275-282
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• 2017

In this paper, using a pattern transformation triggered by deformation, we propose a porous structure that exhibits the characteristic of negative Poisson's ratio in both tension and compression. Due to the lack of torque for rotational motion of ligaments, the existing porous structure of circular holes shows positive Poisson's ratio under tension loading. Also, the porous structure of elliptic holes has a drawback of low durability due to stress concentration. Thus, we design curved ligaments to increase the rotational torque under tension and to alleviate the stress concentration such that strain energy is uniformly distributed in the whole structure. The developed structure possesses better stiffness and durability than the existing structures. It also exhibits the negative Poisson ratio in both compression and tension of 10% nominal strain. Through nonlinear finite element analysis, the performance of developed structure is compared with the existing structure of elliptic holes. The developed structure turns out to be significantly improved in terms of stiffness and durability.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.3
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• pp.1-10
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• 2008

The seismic performance of a structure designed without consideration of seismic loading can be effectively enhanced through seismic rehabilitation. The appropriate level of rehabilitation should be determined based on the decision criteria that minimize the anticipated earthquake-related losses. To estimate the anticipated losses, seismic risk analysis should be performed considering the probabilistic characteristics of the hazard and the structural damage. This study presents the decision procedure in which the probabilistic seismic demand model is utilized for the effective estimation and minimization of the total seismic losses through seismic rehabilitation. The probability density function and the cumulative distribution function of the structural damage for a specified time period are established in a closed form, and are combined with the loss functions to derive the expected seismic loss. The procedure presented in this study could be effectively used for making decisions on the seismic rehabilitation of structural systems.

• Spatial Information Research
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• v.12 no.2
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• pp.181-191
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• 2004

Nowadays, GPS-photogrammetry can be applied to the basemap production, a land register and NGIS. And from now on, as the increase of GPS receiver rate, the study on the interpolation methods considering the exact movement of an aircraft at photoflight and the study on the supplement of GPS defect by INS are required continuously. GPS-Photogrammetry, which are based on the direct measurement of the projection centers and attitude at the moment of camera exposure time through loading the GPS receiver in aircraft. This photogrammetric methods can of for us to acquire the exterior orientation parameters with only minimum ground control points, even the ground control process could be completely skipped. Consequently, we can drastically reduce the time and cost far the mapping process. In this thesis, two test flights were conducted in area to evaluate the performance of accuracy and efficiency through the analysis of results between the two photogrammetric methods, that is, traditional photograrammetry, GPS-Photogrammetry. Test results shows that a large variety of advantages of GPS-Photogrammetry against traditional photogrammetry is to be verified. Especially, the number of ground control points for the exterior orientation could be saved more than 70～80%, and the cost far map production 30～50%, respectively. In addition, it was convinced that the large reduction of control points has not any effect on the block accuracy.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.203-210
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• 2007

This paper treats optimal route safety assessment system at seaway based on weather forecasting data through INMARSAT. Since early times, captain have been sailing to select the optimum route considering the weather, ship loading status condition and operational scheduling empirically. However, it is rare to find digitalized onboard route support system whereas weather facsimile or wave and swell chart are utilized for the officer, based on captain's experience. In this paper, optimal route safety assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA(estimated time of arrival) and fuel consumption that shipping company. and captain are requiring to evaluate for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method Basically, the weather forecast is assumed to be prepared previously in order to operate this system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1145-1151
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• 2015

High pressure components of a gas turbine engine must operate for a long life under severe conditions in order to maximize the performance and minimize the maintenance cost. Enhanced cooling design, thermal barrier coating techniques, and nickel-base superalloys have been applied for overcoming them and furthermore, material modeling, finite element analysis, statistical techniques, and etc. in design stage have been utilized widely. This article aims to evaluate the effects on the low cycle fatigue life of the high pressure turbine nozzle caused by different turbine inlet temperature profiles and installation conditions and to investigate the most favorable operating condition to the turbine nozzle. To achieve it, the structural analysis, which utilized the results of conjugate heat transfer analysis as loading boundary conditions, was performed and its results were the input for the assessment of low cycle fatigue life at several critical zones.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.314-321
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• 2016

Conventional removable partial dentures (RPDs) with distal extensions are associated with some problems, including lack of stability that calls for frequent relining, and cantilever actions of claps that can produce excessive loading to abutment teeth, and the need for unesthetic retentive arm clasps. Therefore, IARPDs (Implant-assisted RPD) that use implants to support or retain RPDs has been reported to improve stability, esthetics and masticatory performance of RPDs. Also, an IARPD that has zirconia occlusal table can prevent the incongruity of occlusal plane and the extrusion of antagonistic tooth. In this case of partially edentulous patient with crossed occlusion, each edentulous area was restored with implant fixed prosthesis and implant retained partial denture to suit each situation. Through the procedure, satisfactory outcomes were achieved both in functional and esthetic aspects.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.147-156
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• 2010

There are four key factors for gas-phase biofilters; biocatalysts(microorganisms), packing materials, design/operating techniques, and diagnosis/management techniques. Biofilter performance is significantly affected by microbial community structures as well as loading conditions. The microbial studies on biofilters are mostly performed on basis of culture-dependent methods. Recently, advanced methods have been proposed to characterize the microbial community structure in environmental samples. In this study, the physiological, biochemical and molecular methods for profiling microbial communities are reviewed, and their applicability to biofilters is discussed. Community-level physiological profile is based on the utilization capability of carbon substrate by heterotrophic community in environmental samples. Phospholipid fatty acid analysis method is based on the variability of fatty acids present in cell membranes of different microorganisms. Molecular methods using DNA directly extracted from environmental samples can be divided into "partial community DNA analysis" and "whole community DNA analysis" approaches. The former approaches consist in the analysis of PCR-amplified sequence, the genes of ribosomal operon are the most commonly used sequences. These methods include PCR fragment cloning and genetic fingerprinting such as denaturing gradient gel electrophoresis, terminal-restriction fragment length polymorphism, ribosomal intergenic spacer analysis, and random amplified polymorphic DNA. The whole community DNA analysis methods are total genomic cross-DNA hybridization, thermal denaturation and reassociation of whole extracted DNA and extracted whole DNA fractionation using density gradient.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.368-376
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• 2003

Cyclodextrin glucanotransferase (CGTase) from Paenibacillus sp. JB-13 was immobilized on various carriers by several immobilization methods such as ionic binding, covalent linkage and ultrafiltration to improve the process performance. The ultrafiltration and covalent linkage with CNBr-activated sepharose 4B were found as the best method for immobilization of CGTase. The ability of CGTase immobilization onto CNBr-activated sepharose 4B was as high as 18,000 units/g resin when the conditions was as follows: contact time 9 hrs at $37^{\circ}C$, pH 6.0, 100 nm and enzyme loading 24,000 units/g resin. The optimum conditions for production of 2-O-$\alpha$-D-Glucopyranosyl L-Ascorbic acid by immobilized CGTase turned out to be: pH 5.0, temperature $37^{\circ}C$, 20% substrate solution containing 8% (w/v) of soluble starch and 12% (w/v) of L-ascorbic acid sodium salt, 100 rpm, far 25 hrs and with 800 units of immobilized CGTase/ml substrate solution. Moreover the CGTase activity could be stably maintained for 8 times of repetitive reactions after removing products by ultrafiltration through YM 10 membrane.