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Han S.-H.,Korean Intellectual Property Office | Bang M.-S.,Korea National University of Transportation
Smart Structures and Systems | Year: 2012

This study was intended to efficiently perform the probabilistic optimal safety assessment of steel cable-stayed bridges (SCS bridges) using stochastic finite element analysis (SFEA) and expected life-cycle cost (LCC) concept. To that end, advanced probabilistic finite element algorithm (APFEA) which enables to execute the static and dynamic SFEA considering aleatory uncertainties contained in random variable was developed. APFEA is the useful analytical means enabling to conduct the reliability assessment (RA) in a systematic way by considering the result of SFEA based on linearity and nonlinearity of before or after introducing initial tensile force. The appropriateness of APFEA was verified in such a way of comparing the result of SFEA and that of Monte Carlo Simulation (MCS). The probabilistic method was set taking into account of analytical parameters. The dynamic response characteristic by probabilistic method was evaluated using ASFEA, and RA was carried out using analysis results, thereby quantitatively calculating the probabilistic safety. The optimal design was determined based on the expected LCC according to the results of SFEA and RA of alternative designs. Moreover, given the potential epistemic uncertainty contained in safety index, failure probability and minimum LCC, the sensitivity analysis was conducted and as a result, a critical distribution phase was illustrated using a cumulative-percentile.

Im S.Y.,Korean Intellectual Property Office | Yu S.S.,Chungnam National University
Energy | Year: 2012

Vortex tubes are used in many industrial fields as parts for refrigerating machines due to their many intrinsic benefits. Although the use of these types of tubes has become common, the characteristics of energy separation associated with these tubes have yet to be vigorously researched. In this study, a counter-flow type of vortex tube is employed to investigate the energy separation characteristics with various geometric configurations. As a preliminary step, the effect of the nozzle area ratio and the inlet pressure were studied given a selected tube length (L=14D). The temperature distribution inside the vortex tube was measured to understand the physics of the energy separation phenomena. The measurement showed that the temperature distribution on the hot air side recovers to the inlet temperature at a cold air mass fraction of 0.5 (y c) with two types of nozzle area ratios. A parametric study was conducted to evaluate the performance of the vortex tube with various geometric structures and operating inlet pressures. The results show that variation of the cold exit orifice hole diameter significantly influences the energy separation between two exits. © 2011 Elsevier Ltd.

Sul I.H.,Korean Intellectual Property Office | Youn J.R.,Seoul National University | Song Y.S.,Dankook University
Carbon | Year: 2011

A new protocol is proposed for quantitatively characterizing the dispersion state of carbon nanotubes (CNTs) embedded in a composite. Such characterization will allow CNT-filled composites to be designed and tailored in more systematic manner. CNTs/polymer composites with different dispersions and distribution states were prepared and their structure was examined. Quantitative image analysis was performed to obtain a "positional randomness index" that involves the contributions from the dispersion and distribution of nanoparticles. © 2010 Elsevier Ltd. All rights reserved.

Kim S.S.,Yeungnam University | Lee J.,Korean Intellectual Property Office
Carbohydrate Polymers | Year: 2014

Polyacrylonitrile (PAN)-chitosan double-face films and nanofibers were manufactured. PAN and a chitosan salt were dissolved in dimethyl sulfoxide, and then thin-layered on a glass plate or electro-spun followed by coagulation in sodium hydroxide solution. The morphology of the PAN-chitosan double-face films and nanofibers was analyzed by scanning electron microscopy. The thermal behavior and the glass transition temperature of PAN-chitosan blends were assessed by differential scanning calorimetry and dynamic mechanical analysis, respectively. The antibacterial efficacy was measured by a swatch test with bacterial suspensions. The PAN-chitosan nanofibers produced a 5-log reduction against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus. © 2013 Elsevier Ltd. All rights reserved.

Kim S.S.,Yeungnam University | Lee J.,Korean Intellectual Property Office
Industrial and Engineering Chemistry Research | Year: 2013

m-Aramid/chitosan hybrid films and nanosized webs were produced. The m-aramid and chitosan salt were dissolved in dimethyl sulfoxide followed by coagulation in a sodium hydroxide solution to produce the m-aramid/chitosan film. An electro-spinning process was used to prepare the nanosized web to increase the surface area of the m-aramid/chitosan hybrid composite for antimicrobial properties. The morphology of the m-aramid/chitosan hybrid composite was analyzed by scanning electron microscopy. The miscibility of the hybrid composite was determined by Fourier transform infrared spectroscopy and X-ray diffraction. The antimicrobial efficacy was measured by a swatch test with bacterial suspensions. The nanosized webs, which had enhanced surface area, produced a 7-log reduction against Escherichia coli and Staphylococcus aureus. © 2013 American Chemical Society.

Kim S.S.,Yeungnam University | Lee J.,Korean Intellectual Property Office
Industrial and Engineering Chemistry Research | Year: 2013

Antimicrobial polyacrylonitrile (PAN)/m-aramid hybrid film was prepared. PAN and m-aramid were dissolved in dimethyl sulfoxide, thin-layered on a glass plate, and then coagulated in distilled water. The morphology of the PAN/m-aramid hybrid film was analyzed by scanning electron microscopy. The molecular interaction between PAN and m-aramid was assessed by dynamic mechanical analysis. The antimicrobial efficacy was measured by a swatch test using bacterial suspensions. The PAN/m-aramid hybrid film produced a 7-log reduction against Escherichia coli and Staphylococcus aureus within 5-min contact time. © 2013 American Chemical Society.

Hwang S.D.,Korean Intellectual Property Office | Kwon H.G.,Yonsei University | Cho H.H.,Yonsei University
Energy | Year: 2010

In this study, heat transfer and thermal performance of a periodically dimple-protrusion patterned surface have been investigated to enhance energy-efficiency in compact heat exchangers. The local heat transfer coefficients on the dimple/protrusion walls are derived using a transient TLC (Thermochromic Liquid Crystal) technique. The periodically patterned surface is applied to the bottom wall only or both the bottom and top walls in the test duct. The ratio of dimple (or protrusion) depth to duct height is 0.25, and the ratio of duct height to dimple (or protrusion) print diameter is 1.15. The Reynolds number is tested in low range values from 1000 to 10000. On the single-side patterned walls, various secondary flows generated from the dimple/protrusion coexist. The vortices induced from the upstream affect strongly on the downstream pattern. For the double-side patterned wall case, vortex interaction affected by the opposite wall enhances highly the heat transfer. The heat transfer augmentation is higher in the lower Reynolds number due to the effective vortex interactions. Therefore, the performance factor considering both heat transfer enhancement and pressure loss increases with decreasing the Reynolds number. © 2010 Elsevier Ltd.

Kye W.-H.,Korean Intellectual Property Office
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2012

A new encoding scheme for information transfer with modulated delay time in a time-delay system is proposed. In the scheme, the message is implicitly encoded into the modulated delay time. The information transfer rate as a function of encoding redundancy in various noise scales is presented and it is analyzed that the implicit encoding scheme (IES) has stronger resistance against channel noise than the explicit encoding scheme (EES). In addition, its advantages in terms of secure communication and feasible applications are discussed. © 2012 Elsevier B.V.

Lee K.C.,Korean Intellectual Property Office | Yoo C.H.,Auburn University
Journal of Structural Engineering (United States) | Year: 2012

To enhance the strength and constructability of rectangular (or trapezoidal) tubular compression members, reinforced or unreinforced concrete may be filled in the tube. Longitudinal stiffeners are often attached to increase the local buckling strength of the thin-walled skin. The effect of important design parameters on the minimum required stiffener moment of inertia was investigated numerically in this study by examining the residual stress distributions, initial imperfections, and elastic and inelastic buckling stresses of a number of hypothetical models. Because the thin-walled panel can only buckle (bulge) out from the concrete core, the buckling mode shape of a panel with multiple stiffeners resembles a waffle slab. A series of parametric studies was performed to characterize and quantify the analytically collected data. A new equation for the minimum required moment of inertia for the longitudinal stiffeners was derived. Through the evaluation of a few selected case studies and a design example, the validity and reliability of the proposed equation was demonstrated. © 2012 American Society of Civil Engineers.

News Article | November 10, 2016
Site: www.techradar.com

A roll-up TV might sound like it belongs in the realm of sci-fi, but a recent patent filing from Samsung suggests the technology might be closer than you think. The patent, which has been filed with both the United States Patent and Trademark Office and the Korean Intellectual Property Office, states that it’s for a “rollable display device can be used for TVs, monitors, game devices, multimedia devices and so on”. Apparently this technology could be used for either LCD or LED displays, and interestingly Samsung has also indicated that it might want to use it for OLED displays, despite its repeated assurances that it has no interest in the technology . Not everyone will have a use for a roll-up TV, but it’s something that might come in handy for someone who ordinarily wouldn’t have enough space for a massive screen. For example, if you’re living in a small flat where you normally do most of your watching on a small laptop or tablet screen, you could conceivably keep a TV rolled up to bring out when you have guests round. Or you could leave the TV set up 90% of the time, with the option of tucking it away when you’re hosting a party, when it might get damaged by a rowdy guest. Samsung isn't the first TV company to investigate the possibility of roll-up TVs. Back in 2014, LG showed off an 18-inch rollable display, but come CES 2016 the company appeared to be no closer to its dream of delivering a flexible OLED panel of more than 60 inches, despite setting itself a target of 2017 for the tech. As always with these filings there’s no guarantee that the technology will ever make it to market, but it’s an interesting direction for Samsung to take, especially with the TV market being as competitive as it is. When contacted for comment, a representative from the company said, “Samsung does not comment on rumour or speculation.”

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