• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.551-556
• /
• 2004

The theoretical method is developed to investigate the vibration characteristics of the combined cylindrical shells with an annular plate joined to the shell at any arbitrary axial position. The structural rotational coupling between shell and plate is simulated using the rotational artificial spring. For the translational coupling, the continuity conditions for the displacements of shell and plate are used. For the uncoupled annular plate, the transverse motion is considered and the in-plane motions are not. And the additional transverse and in-plane motions of the coupled annular plate by shell deformation are considered in analysis. Theoretical formulations are based on Love's thin shell theory. The frequency equation of the combined shell with an annular plate is derived using the Rayleigh-Ritz approach. The effect of inner-to-outer radius ratio, axial position and thickness of annular plate on vibration characteristics of combined cylindrical shells is studied. To demonstrate the validity of present theoretical method, the finite element analysis is performed.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.10
• /
• pp.751-759
• /
• 2003

The theoretical method is developed to investigate the vibration characteristics of the sloshing and bulging mode for the circular cylindrical storage tank with an annular plate on free surface. The cylindrical tank is filled with an inviscid and incompressible liquid. The liquid domain is limited by a rigid cylindrical surface and a rigid flat bottom. As the effect of free surface waves Is taken into account in the analysis, the bulging and sloshing modes are studied. The solution for the velocity potential of liquid movement is assumed as a suitable harmonic function that satisfies Laplace equation and the relevant boundary conditions. The Rayleigh-Ritz method is used to derive the frequency equation of the cylindrical tank. The effect of Inner-to-outer radius ratio and thickness of annular plate and liquid volume on vibration characteristics of storage tank is studied. The finite element analysis is performed to demonstrate the validity of present theoretical method.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.10
• /
• pp.767-776
• /
• 2003

The theoretical method is developed to Investigate the nitration characteristics of the combined cylindrical shells with an annular plate joined to the shell at any arbitrary axial position. The structural coupling between shell and plate is simulated using two types of artificial springs a translational spring is introduced for translational coupling and a rotational spring is used for rotational coupling. The springs are continuously distributed along circumferential direction. Using the Rayleigh-Ritz method the natural frequencies and mode shapes of the combined shell with an annular plate examine. The effect of Inner-to-outer radius ratio, axial position of annular plate and length-to-radius ratio of shell on vibration characteristics of combined cylindrical shells is studied. The theoretical results are verified by comparison with FEM results.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.7
• /
• pp.884-891
• /
• 2016

A secondary injection system in a diesel engine has benefits: it can be controlled independently without interrupting engine control, it can be adapted to various layouts for exhaust systems, and it pose no reductant dilution problems compared to post injection systems in the combustion chamber or other supplemental reductant injections. In a secondary injection system, the efficiency of the catalyst depends on the method of reducing the supply. The reductant needs to be maintained and optimized with constant pressure, the positions and angles of injector is a very important factor. The concentration and amount of reductant can be changed by adjusting secondary injection conditions. However, secondary injection is highly dependent upon the type of injector, injection pressure, atomization, spray technology, etc. Therefore, it is necessary to establish injection conditions the spray characteristics must be well-understood, such as spray penetration, sauter mean diameter, spray angle, injection quantity, etc. Uniform distribution of the reductant corresponding to the maximum NOx reduction in the DeNOx catalyst system must also assured. With this goal in mind, the spray characteristics and impingement plate types of a secondary injector were analyzed using visualization and digital image processing techniques.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.3 s.234
• /
• pp.439-446
• /
• 2005

The theoretical method is developed to investigate the vibration characteristics of the combined cylindrical shells with an annular plate joined to the shell at any arbitrary axial position. The structural rotational coupling between shell and plate is simulated using the rotational artificial spring. For the translational coupling, the continuity conditions for the displacements of shell and plate are used. For the uncoupled annular plate, the transverse motion is considered and the in-plane motions are not. And the additional transverse and in-plane motions of the coupled annular plate by shell deformation are considered in analysis. Theoretical formulations are based on Love's thin shell theory. The frequency equation of the combined shell with an annular plate is derived using the Rayleigh-Ritz approach. The effect of inner-to-outer radius ratio, axial position and thickness of annular plate on vibration characteristics of combined cylindrical shells is studied. To demonstrate the validity of present theoretical method, the finite element analysis is performed.

• Resources Recycling
• /
• v.10 no.3
• /
• pp.29-36
• /
• 2001

Cyclic voltammetry has been applied in the basic studies for the treatment and recovery of heavy metal component contained in wastewater by electrochemical reduction. The electrochemical behaviors of zinc ion for zinc metal electrode and carbon elec-trode were characterized by voltammograms and it was showed that zinc ions were reduced to metallic form below -0.76 V vs SHE. The change in the features of crystalline form of metallic zinc upon oxidation and reduction reaction was observed by X-ray diffraction method and the Am analysis verified that zinc ions were reduced to metal on copper plate. The results of this study were regarded to be important and meaningful in the treatment of heavy metal containing wastewater and, as a result, in the obtainment of metallic product by electrochemical method.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.7
• /
• pp.968-973
• /
• 2019

This study presents the characteristics of a pressure drop and uniformity index for a particulate matter reduction device with a perforated plate and mixer for marine diesel engines. The perforated plate and mixer equipped on the particulate matter reduction device induce an increase of exhaust gas reduction performance by increasing the uniformity index. Whereas, the perforated plate induces pressure drop increases in the particulate matter reduction device. Therefore to calculate the effect of the uniformity index and pressure drop of the perforated plates and mixer, this study combines several cases using five types of perforated plates and one type of mixer. Consequently, these results were analyzed to determine the optimized type and position of the perforated plate and mixer.

• Applied Chemistry for Engineering
• /
• v.28 no.5
• /
• pp.587-592
• /
• 2017

Uniform and optimum sized silver nanoplates were synthesized through the liquid phase reduction method by using silver nitrate solution as a starting chemical, dimethylformmide (DMF) as a reducing solvent, and polyvinylpyrrolidone (PVP) as reducing and surfactant agents. Synthesized and also film samples were characterized by using SEM, TEM, UV-Vis-NIR spectroscopy, particle size analyzer (PSA), and XRD. Triangle nanoplates with the size of 100~200 nm were found from the sample synthesized at $70^{\circ}C$ for 72 h using silver nitrate, DMF and 26 wt% PVP. The sample could reflect near-infrared light because it showed the maximum absorbing peak at about 1,000 nm. When the content or particle size of silver nanoplates increased in coating solutions, the transmittance decreased and the reflectance increased in film samples.

• Journal of the Microelectronics and Packaging Society
• /
• v.29 no.4
• /
• pp.71-75
• /
• 2022

In this research, Fe-Ni alloy films were electrodeposited on stainless steel (SS304 and SS430) and Ti plates to investigate the effects of surface conditions of cathode on deposits. The Ti plates were electropolished in 3 M H₂SO₄-methanol electrolytes at various conditions before electrodeposition, and unpolished Ti and the optimized specimen, polished at 10 V for 8 min, were used as cathode. The anomalous codeposition, the phenomenon which more active Fe is reduced preferentially, occurred on all substrate, however, there were differences in composition of all deposits. As the results of potential monitoring during electrodeposition, it was confirmed that the larger overpotential was applied to the deposition cell when using Ti cathode, leading to high Fe content of deposits from unpolished Ti due to increase in nucleation of Fe. Also, it was founded that the polished Ti can reduced deposition overpotential.

• Journal of the Korean Institute of Gas
• /
• v.26 no.2
• /
• pp.49-55
• /
• 2022

According to reinforce environmental regulations, coal power plants have used selective catalytic reduction using ammonia as a reducing agent to reduce the amount of nitrogen oxide generation. The purpose of the present study was to derive a mixing device for effectively mixing dilute air and ammonia in the ammonia mixing pipe by performing computational fluid dynamic analysis. The mixing effect was compared by analysing the %RMS of ammonia concentration at the down stream cross section in the mixing pipe and the 16 outlets based on the case 1-1 shape, which is an existing mixing pipe without a mixing device. The mixing device was performed by changing the positions of a square plate on the downstream side of the ammonia supply pipe and an arc-shaped plate on the wall of the mixing pipe. In the case of the existing geometry(Case 1-1), the %RMS of ammonia concentration at the 16 outlets was 29.50%. The shape of the mixing device for Case 3-2 had a square plate on the downstream side of the ammonia supply pipe and an arc plate was installed adjacent to it. The %RMS of ammonia concentration for Case 3-2 was 2.08% at 16 outlets and it could be seen that the shape of Case 3-2 was the most effective mixing shape for ammonia mixing.