• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.813-824
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• 2010

Thermal conductivity of soils is one of the most important parameters to design horizontal ground heat exchangers. It is well known that the thermal conductivity of soil is strongly influenced by its density and water content because of soil's particulate structure. This paper reviewed and evaluated some of the commonly used prediction models for thermal conductivity of soils with the experimental data available in the literature. Semi-theoretical models for two-component materials were found inappropriate to estimate the thermal conductivity of dry state sands. It came out that the model developed by Cote and Konrad gave the best overall prediction for unsaturated sands available in the literature. Also, a parametric analysis is conducted to investigate the effect of thermal conductivity and water content, soil type on the horizontal ground heat exchanger design. The analysis shows that a required pipe length for the horizontal ground heat exchanger is reduced with the increase of soil thermal conductivity and water content. The calculation results also show that the dimension of the horizontal ground heat exchanger can be reduced to a certain extent by using backfilling material with a higher thermal conductivity of solid particles.

• Biomedical Science Letters
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• v.19 no.1
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• pp.41-47
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• 2013

Pluripotent stem cells (PSCs) have lots of potential in biomedical sciences owing to its potential to differentiate into any kind of cells in the body. However, it is still a challenge to culture PSCs on a large scale for application to regenerative medicine. Herein, we introduce a synthetic polymer that enables large-scale suspension culture of human PSCs. By employing suspension culture, it became unnecessary to use conventional substrata such as mouse embryonic fibroblast (MEF) or Matrigel$^{TM}$, which are believed to be main causative sources of xenogeneic contamination in cultured human PSCs in vitro. Human PSCs were cultured in the medium in which elastin-like polypeptide (ELP) dissolved. The ELP in the medium became harden as temperature increases by transforming the medium into a semi-solid gel that supported growth of human PSCs in suspension. Gel-sol transition temperature of ELP can be adjusted by modifying the peptide sequence in which 5 amino acids, Val-Pro-Gly-Xaa-Gly, repeated sequentially. We constructed 3D suspension media having transition temperature around $33{\sim}35^{\circ}C$ using an ELP consisted of 40, 60, or 80 repeats of a monomer, which was Val-Pro-Gly-Val-Gly. Among the ELPs, ELP80 was chosen as the best ELP to support growth of human PSCs in suspension culture. This result suggests that the ELP80 can be a medium component for culturing human PSCs in large-scale.

• Earthquakes and Structures
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• v.11 no.6
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• pp.943-966
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• 2016

Recently, magnetorheological elastomer (MRE) material and its devices have been developed and attracted a good deal of attention for their potentials in vibration control. Among them, a highly adaptive base isolator based on MRE was designed, fabricated and tested for real-time adaptive control of base isolated structures against a suite of earthquakes. To perfectly take advantage of this new device, an accurate and robust model should be built to characterize its nonlinearity and hysteresis for its application in structural control. This paper first proposes a novel hysteresis model, in which a nonlinear hyperbolic sine function spring is used to portray the strain stiffening phenomenon and a Voigt component is incorporated in parallel to describe the solid-material behaviours. Then the fruit fly optimization algorithm (FFOA) is employed for model parameter identification using testing data of shear force, displacement and velocity obtained from different loading conditions. The relationships between model parameters and applied current are also explored to obtain a current-dependent generalized model for the control application. Based on the proposed model of MRE base isolator, a second-order sliding mode controller is designed and applied to the device to provide a real-time feedback control of smart structures. The performance of the proposed technique is evaluated in simulation through utilizing a three-storey benchmark building model under four benchmark earthquake excitations. The results verify the effectiveness of the proposed current-dependent model and corresponding controller for semi-active control of MRE base isolator incorporated smart structures.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.1
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• pp.36-42
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• 2024

Roll-to-roll processing holds an integral position within the manufacturing landscape, and its significance reverberates across numerous industries. This versatile technology platform encompasses a diverse array of process methods and accommodates a wide spectrum of material categories, making it a cornerstone of modern production. Within this expansive domain, two commonly employed coating techniques, namely the slot die and gravure coating methods, have earned their prominence for their precision and efficiency in delivering flawless coatings. Additionally, the realm of drying processes relies heavily on thermal drying, infrared (IR) drying, and ultraviolet (UV) drying methods to expedite the transformation of materials from their liquid or semi-liquid states to solid, ready-to-use products. The undeniable importance of roll-to-roll processing lies in its ability to streamline manufacturing processes, reduce costs, and enhance product quality. This article embarks on a comprehensive journey to fathom the depth of this importance by delving into the intricacies of these common roll-to-roll process methods. Through rigorous research and meticulous data collection, we aim to shed light on the pivotal role these techniques play in shaping various industries and advancing the world of manufacturing. By understanding their significance, we can harness the full potential of roll-to-roll processing and pave the way for innovation and excellence in production.

• The Research Journal of the Costume Culture
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• v.19 no.2
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• pp.255-268
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• 2011

This study carefully explored today's preferable beauty images, analyzed Korean adult purchasing trends of functional underwear and market analysis of the most popular items and their designs. Information and methods are based largely on reference book material as well as analysis of real domestic data. The paper's research timeline simply spans the last three years, as in accordance with project parameters. Helping improve body shape, foundation literally means 'substructur' and 'base'. The formativeness in these adult foundations typically has three main category classifications. First, natural modern image. This is where we find natural beauty including that which embodies a cool modern sense. Here, you can often see such patterns as either stripes and dots, or simply no patterns at all. Colors are green, red-brown, incarnadine, or khaki from a natural or basic human body color. Its products are marketed as both solid and durable eco-friendly materials, and lace-seethrough. Fashion's natural modern image is undoubtedly the most popular style purchase choice among both genders. Second, sweet romantic image. This mainly consists of two concepts : a sweet and romantic theme, and visual appeal. Patterns include flowers, lips, heart, stars, candies and various other appealing characters. Its main colors are pink, yellow, red, purple, and violet. Products are decorated with laces, frills and ribbons. Since only men's semi-girdles carry such designs, this fashion foundation is largely a women's world. While men show an obvious interest in foundation, they still mostly prefer the choice of natural modern images. Third, mystic sexy image. This is defined as all feminine images of mysterious and classic sexual beauty. Patterns are variously expressed as paisley, flowers, and geometric. Colors are largely purple, blue-green, royal-blue, cobalt, and black. Products are commonly decorated with beading, spangles, hot-fixes and so on. While this image can be found in all kinds of women's foundations, it typically appears only in men's corsets and girdles.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.2
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• pp.100-107
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• 2010

Introduction: A cyst is a closed pathologic sac containing fluid or semi-solid material in central region. The most common conventional treatment for a cyst is enucleation. It was reported that spontaneous bone healing could be accomplished without bone grafting. We are trying to evaluate bone reconstruction ability by analyzing panorama radiograph and computed tomography (CT) scan with retrograde studying after cyst enucleation. In this way we are estimating critical size defect for spontaneous healing without bone graft. Materials and Methods: The study comprised of 45 patients who were diagnosed as cysts and implemented enucleation treatment without bone graft. After radiograph photo taking ante and post surgery for 6, 12, 18, 24 months, the healing surface and volumetric changes were calculated. Results: 1. Spontaneous bone healing was accomplished clinically satisfying 12 months later after surgery. But analyzing CT scan, defect volume changes indicate 79.24% which imply incomplete bone healing of defect area. 2. Comparing volume changes of defect area of CT scan, there are statistical significance between under $5,000mm^{3}$ and over $5,000mm^{3}$. The defect volume of $5,000mm^{3}$ shows $2.79{\times}1.91$cm in panoramic view. Conclusion: Bone defects, which are determined by a healed section using a panoramic view, compared to CT scans which do not show up. Also we can estimate the critical size of defects for complete healing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.223-231
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• 2013

This paper presents a time-domain Gauss-Newton full-waveform inversion method for the material profile reconstruction in heterogeneous semi-infinite solid media. To implement the inverse problem in a finite computational domain, perfectly-matchedlayers( PMLs) are introduced as wave-absorbing boundaries within which the domain's wave velocity profile is to be reconstructed. The inverse problem is formulated in a partial-differential-equations(PDE)-constrained optimization framework, where a least-squares misfit between measured and calculated surface responses is minimized under the constraint of PML-endowed wave equations. A Gauss-Newton-Krylov optimization algorithm is utilized to iteratively update the unknown wave velocity profile with the aid of a specialized regularization scheme. Through a series of one-dimensional examples, the solution of the Gauss-Newton inversion was close enough to the target profile, and showed superior convergence behavior with reduced wall-clock time of implementation compared to a conventional inversion using Fletcher-Reeves optimization algorithm.

• Journal of environmental and Sanitary engineering
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• v.6 no.2
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• pp.33-47
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• 1991

1. Water supply treatment plants personnel could not test the water quality control, because most of them rely on the provincial health laboratories about water quality rely rant test. However, in future, plants have to been provided the facilities and equipment of water quality laboratory. 2. Chlorination methods are 89.5% of liquid chlorine and 10.5% of solid chlorine, and the cost per 1 $\m^{3}$ of chlorination is about 1.30 won which chlorination cost is very cheap as 1/142 of drinking water production cost. Input method of chlorine is 35% of automatic method, 56% of semi-automatic, and 9% of other methods, and this is no problem 3. Residual effects of chlorination, in the case of distilled water as a standardized material and 0.2 ppm of seperated residual chlorine, were continued 32 hours in $0^{\circ}C$, and 25 hour in $20^{\circ}C$, of water temperature and in the case of 0.4 ppm of seperated residual chlorine were continued 47 hours in $0^{\circ}C$ and 23 hours in $20^{\circ}C$. 4. In the case of 4 ppm of seperated residual chlorine, residual effects were continued 23 hours in $5^{\circ}C$, 90 hours in $10^{\circ}C$, 78 hours in $15^{\circ}C$, and 60 hours in $20^{\circ}C$ : by the temper; lure of water, continuing residual effects of chlorination are different, so we have to car for the warm season chlorination in the hider temperature. 5. Chlorination effects of drinking waters in the case of 0.4 ppm of seperated residual chlorine were continued 237 hours in $22^{\circ}C$ water : and in the case of rechlorination as 4 ppm of residual chlorine, continued 71 hours in $22^{\circ}C$ water.

• YAKHAK HOEJI
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• v.41 no.1
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• pp.38-47
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• 1997

Using a concentric cylinder type, rheometer. the steady shear flow properties of vaseline were measured over the temperature range of 20~70${\circ}$C. In this paper, the shea rate and temperature dependencies of its flow behavior were investigated and the validity of some flow models was examined. In addition, the flow characteristics over a wide temperature range were quantitatively evaluated by calculating the various material parameters. Main findings obtained from this study can be summarized as follows: (1) At relatively lower temperature range, vaseline is a plastic fluid with a yield stress and its flow behavior shows shear-thinning characteristics. (2) As the temperature increases, the value of a yield stress and the degree of shear-thinning become smaller, consequently, the Newtonian flow behavior occurs at a lower shear rate range. (3) At temperature range lower than 45${\circ}$C, the flow behavior shows much stronger temperature dependence, and a larger activation energy is needed for flow. (4) The Herschel-Bulkley model is the most effective one g$^3$ to predict the flow behavior of vaseline having a yield stress. The validity of the Bingham and Casson models becomes more available with increasing temperature. The flow behavior of vaseline at temperature range higher than 45${\circ}$C can be perfectly described by the Newton model.

• Clean Technology
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• v.2 no.2
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• pp.100-125
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• 1996

After recycle of spent materials has been optimised, there remains a proportion of waste which must be dealt with in the most environmentally friendly manner available. For materials such as municipal waste, clinical waste, toxic waste and special wastes such as tyres, incineration is often the most appropriate technology. The study of incineration must take a process system approach covering the following aspects: ${\bullet}$ Collection and blending of waste, ${\bullet}$ The two stage combustion process, ${\bullet}$ Quenching, scrubbing and polishing of the flue gases, ${\bullet}$ Dispersion of the flue gases and disposal of any solid or liquid effluent. The design of furnaces for the burning of a bed of material is being hampered by lack of an accurate mathematical model of the process and some semi-empirical correlations have to be used at present. The prediction of the incinerator gas phase flow is in a more advanced stage of development using computational fluid dynamics (CFD) analysis, although further validation data is still required. Unfortunately, it is not possible to scale down many aspects of waste incineration and tests on full scale incinerators are essencial. Thanks to a close relationship between SUWIC and Sheffield Heat&Power Ltd., an extended research programme has been carried out ar the Bernard Road Incinerator plant in Sheffield. This plant consists of two Municipal(35 MW) and two Clinical (5MW) Waste Incinerators which provide district heating for a large part of city. The heat is distributed as hot water to commercial, domestic ( >5000 dwelling) and industrial buildings through 30km of 14" pipes plus a smaller pipe distribution system. To improve the economics, a 6 MW generator is now being added to the system.