• Korean Chemical Engineering Research
• /
• v.52 no.6
• /
• pp.768-774
• /
• 2014

SI process is a thermochemical process producing hydrogen by decomposing water while recycling sulfur and iodine. Various technologies have been developed to improve the efficiency on Section III of SI process, where iodine is separated and recycled. EED(electro-electrodialysis) could increase the efficiency of Section III without additional chemical compounds but a substantial amount of $I_2$ from a process stream is loaded on EED. In order to reduce the load, a crystallization technology prior to EED is considered as an $I_2$ removal process. In this work, $I_2$ particle sinking behavior was modeled to secure basic data for designing an $I_2$ crystallizer applied to $I_2$-saturated $HI_x$ solutions. The composition of $HI_x$ solution was determined by thermodynamic UVa model and correlation equations and pure properties were used to evaluate the solution properties. A multiphysics computational tool was utilized to calculate particle sinking velocity changes with respect to $I_2$ particle radius and temperature. The terminal velocity of an $I_2$ particle was estimated around 0.5 m/s under considered radius (1.0 to 2.5 mm) and temperature (10 to $50^{\circ}C$) ranges and it was analyzed that the velocity is more dependent on the solution density than the solution viscosity.

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.634-638
• /
• 2003

For the investigation of the properties of aqueous fibroin solution, the variation of molecular weight by agregation of silk, morphology and difference of molecular weight at pI value was investigated. The distribution of molecular weight investigated using gel filtration chromatography and formation of aggregates were confirmed by using Field emission scanning electron microscope. The precipitation of fibroin solution at its pI value was compared by molecular weight distribution and the formation of fibroin aggregated were investigated. The aggregation kinetics were investigated at various condition.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.11 no.3 s.25
• /
• pp.25-32
• /
• 1987

The purpose of this study is to investigate optical behaviour of coloring matter of gromwell -extracted by water, acetic acid/methanol, and the other solvents. The results were as following: UV, VIS spectra of the solution of coloring matter of gromwell extracted by water at below $80^{\circ}C$ did not reveal in the range of the visible light wavelength and coloring matter of gromwell decomposed to blue particle at $95^{\circ}C$. The solution extracted by acetic acid/methanol was tinged with reddish purple and its spectra shifted to the longer wavelength according to increase of the solvent temperature. The color of the solution extracted by water became extinct as time went by, but that extracted by acetic acid/methanol kept up original color. In case of dried gromwell, extraction by acetic acid/methanol was easier than by water, and variation of spectra did not appear but showed hypochromic shift.

• Bulletin of the Korean Mathematical Society
• /
• v.55 no.3
• /
• pp.899-911
• /
• 2018

In this paper, we consider the second-order nonlinear differential equation with the nonlocal boundary conditions. We first reformulate this boundary value problem as a fixed point problem for a Fredholm integral equation operator, and then present a result on the existence and uniqueness of the solution by using the contraction mapping theorem. Furthermore, we establish a sufficient condition on the functions ${\mu}$ and $h_i$, i = 1, 2 that guarantee a unique solution for this nonlocal problem in a Hilbert space. Also, accurate analytic solutions in series forms for this boundary value problems are obtained by the Adomian decomposition method (ADM).

• Journal of the Korean Mathematical Society
• /
• v.53 no.4
• /
• pp.929-967
• /
• 2016

Let p(t, x) be the fundamental solution to the problem $${\partial}^{\alpha}_tu=-(-{\Delta})^{\beta}u,\;{\alpha}{\in}(0,2),\;{\beta}{\in}(0,{\infty})$$. If ${\alpha},{\beta}{\in}(0,1)$, then the kernel p(t, x) becomes the transition density of a Levy process delayed by an inverse subordinator. In this paper we provide the asymptotic behaviors and sharp upper bounds of p(t, x) and its space and time fractional derivatives $$D^n_x(-{\Delta}_x)^{\gamma}D^{\sigma}_tI^{\delta}_tp(t,x),\;{\forall}n{\in}{\mathbb{Z}}_+,\;{\gamma}{\in}[0,{\beta}],\;{\sigma},{\delta}{\in}[0,{\infty})$$, where $D^n_x$ x is a partial derivative of order n with respect to x, $(-{\Delta}_x)^{\gamma}$ is a fractional Laplace operator and $D^{\sigma}_t$ and $I^{\delta}_t$ are Riemann-Liouville fractional derivative and integral respectively.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.3
• /
• pp.179-186
• /
• 2006

End-Labeled Free-Solution Electrophoresis (ELFSE) is a new technique that is a promising bioconjugate method for DNA sequencing (or separation) and genotyping by both capillary and microfluidic device electrophoresis. Because ELFSE enables high-resolution electrophoretic separation in aqueous buffer alone (i.e., without a polymer matrix), it eliminates the need to load viscous polymer networks into electrophoresis microchannels. To achieve microchannel DNA separations with high performance, ELFSE requires monodisperse perturbing entities (i.e., drag-tags), which create a large amount of frictional drag when pulled behind DNA during free-solution electrophoresis, and which have other properties suitable for microchannel electrophoresis. In this article, the theoretical concepts of ELFSE and the required characteristics of the drag-tag molecules for the ultimate performance of ELFSE are reviewed. Additionally, the merits and limitations of current drag-tags are also discussed in the context of recent experimental data of ELFSE separation (or sequencing).

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.9
• /
• pp.2965-2972
• /
• 1996

Transitional flow in an obstructed channel is investigated using numerical simulation. Two-dimensional thin obstacles are mounted symmetrically in the vertical direction and periodically in the streamwise direction. Flow separation occurs at the tip of the sharp obstacles. Depending on the Reynolds number, the flow undergoes Hopf bifurcation as the primary instability leading to a two-dimensional unsteady periodic solution. At higher Reynolds numbers, the unsteady solution exhibits a symmetry-breaking bifurcation which results in an unsteady asymmetric solution. The results are compared with experiments currently available, and show a good agreement.

• Advances in Computational Design
• /
• v.2 no.3
• /
• pp.195-210
• /
• 2017

Simultaneous optimization of trusses which concurrently takes into account design variables related to the size, shape and topology of the structure is recognized as highly complex optimization problems. In this class of optimization problems, it is possible to encounter several unstable mechanisms throughout the solution process. However, to obtain a feasible solution, these unstable mechanisms somehow should be rejected from the set of candidate solutions. This study proposes triangular unit based method (TUBM) instead of ground structure method, which is conventionally used in the topology optimization, to decrease the complexity of search space of simultaneous optimization of the planar truss structures. TUBM considers stability of the triangular units for 2 dimensional truss systems. In addition, integrated particle swarm optimizer (iPSO) strengthened with robust technique so called improved fly-back mechanism is employed as the optimizer tool to obtain the solution for these class of problems. The results obtained in this study show the applicability and efficiency of the TUBM combined with iPSO for the simultaneous optimization of planar truss structures.

• Proceedings of the KIEE Conference
• /
• 1990.07a
• /
• pp.221-223
• /
• 1990

In this study, we have studied the optioal properties and $I_2$ doping effect of Poly(3-Akkylthiophene) solution. The end of speotrum absorbance on the solutions of Poly(3 - Octylthiophene), Poly (3-Dodecylthiophene) and Poly(3-Dooooylthiophene) was dependent on temperature. It is bellved that conrod-coil transition dependent on temperature was rod-coil transition. And absortance peak of Poly (3-Dodecylthiophene) in dichloromethane solution increased with increasing the $I_2$ dopant.

• Journal of Biosystems Engineering
• /
• v.19 no.2
• /
• pp.99-111
• /
• 1994

Automatic control system using microcomputer that have been studied in greenhouse, however, it was very difficult operation with success due to handicap for a various conditions and cultivated plants. This study was performed in order to develop of the basic program and hardware system for automatic control in greenhouse, such as automatic supplying of water, liquefied fertilizer solution and chemical solution. The results were summarized as follows. 1. The program for soil moisture control used by the switch type tensiometer was well operated. 2. The proximity switch was applied as well to water level control but it was very expensive, so low-priced sensor has to be developed. 3. The water meter was not excellent for mixing control of liquefied fertilizer, chemical and water, so water meter for only agricalture has to be developed. 4. Interface system for this study was suited to the developed controller. 5. Automatic control system to supply for water, liquefied fertilizer and chemical solution that was well operated as a fundamental study for product of controller.