• Journal of Electrical Engineering and Technology
• /
• v.10 no.5
• /
• pp.2205-2210
• /
• 2015

Experimental studies have been carried out to study the principle operation of the conductive type wire-mesh tomography sensor and analyse the wire-mesh tomography sensor for the liquid/gas two-phase flow interface and void fraction distribution in a process column. The measurement of the two-phase flows in the process column is based on the cross-sectional local instantaneous conductivity. The sensor consists of two planes of parallel electrode wires with 16 electrodes each and was placed orthogonally with each plane. The sensor electrode wires were made of tinned copper wire with an outer diameter of 0.91 mm which stretched over the sensor fixture. Therefore, this result in the mesh grid size with 5.53×5.53mm². The wire-mesh sensor was tested in a horizontal liquid/gas two-phase flows process column with nominal diameter of 95.6 mm and the sampling frequency of 5882.3529 Hz. The tomogram results show that the wire-mesh tomography provides significant results to represent the void fraction distribution in the process column and estimation error was found in the liquid/gas interface level

• Journal of the Korean Society of Radiology
• /
• v.15 no.7
• /
• pp.975-982
• /
• 2021

The purpose of this study is to evaluate the effect on the phantom for magnetic resonance imaging located nearby by partially shielding RF with a mesh made thinner than hair composed of copper, black metal, and polyester using metallic materials of titanium, which are commonly used for esophageal stents and implants in the body. Magnetic resonance images according to field of view (FOV) were analyzed in the Spin Echo T1 weighted images of TR 500 ms, TE 20 ms, NEX 1, and slice thickness 5mm using a Cardiac coil of 3T Achieva X-series. Aliasing artifact did not occur in FOV 304 mm × 304 mm, but it occurred in 250 mm × 250 mm and 170 mm × 170 mm. In FOV 170 mm × 170 mm, when a mesh was not used, the SNR was measured with 78.23, and when separated by standing a mesh in the middle, it was 215.05, and when completely shielded with a mesh, the SNR was 366.44. In addition, when completely shielded with a mesh, the aliasing artifact was also removed, and signal intensities on the left, middle and right of the image were also able to obtain homogeneous images compared to the previous two cases. In conclusion, if RF is partially shielded with a mesh, aliasing artifact can be removed, and magnetic resonance images with excellent image resolution and homogeneity can be obtained using a small FOV.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.6
• /
• pp.41-48
• /
• 2015

Stainless steel mesh has been used as a filter in various fields, including domestic, medical, etc. However, the surface before machining may have an adverse effect the product quality and performance because it is not smooth. Especially, adsorbed impurities in the surface result in difficulty in cleaning. Therefore, in this paper, we propose an improved surface quality through electrochemical polishing (ECP). Two electrodes, composed of STS304 (anode) and copper (cathode) underwent machining with two conditions according to polishing time and current density. As the polishing time and current density increase, the surface of curvature decreases, and roughness and material removal rate (MRR) improves. The machined surface roughness and image were obtained through the atomic force microscope (AFM) and stereoscopic microscope. The study also analyzed hydrophilic effect through contact angles. This obtains corrosion resistance, smoothness, hydrophilic property, etc.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1400-1405
• /
• 2004

Experimental study is performed to investigate the effect of heat load and operating temperature on the thermal performance of a heat pipe with screen mesh wick. The heat pipe was designed in 200 screen meshes, 500mm length and 12.7mm O.D tube of copper, water as working fluid(4.8g) and nitrogen as non-condensible gas(NCG). The heat pipe used in this study has evaporator, condenser and adiabatic section, respectively. Experimental data of axial wall temperature distribution is presented for heat transport capacity, the temperature of cooling water of condenser, inclination angle, and operating temperature. For the results from this study, it is found that, for the same charging mass of working fluid, the initial operating temperature and the overall wall temperatures of heat pipe are higher for NCG charging mass of $5.0{\times}10^{-6}kg$ and $3.4{\times}10^{-6}kg$, than that of $1.0{\times}10^{-6}kg$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.1
• /
• pp.77-83
• /
• 2004

In this study, the spray cooling heat transfer and working characteristics of the screen wick heat pipe with ultrasonic spray cooling system in condenser were experimentally investigated. The heat pipe was made of copper tube 300 mm long with inner diameter of 11.1 mm. The evaporator and condenser lengths of heat pipe were 40, 200 mm and the wick structure consists of two layer of 100 mesh copper screen. The experimental results show that the ultrasonic spray cooling increases the heat transfer rate on the condenser surface, and the total thermal resistance of heat pipe system decreases remarkably. A comparison is made for the two working fluids, water and ethanol. The surface temperature of the ethanol tube in evaporator section becomes higher than that of the water tube. Thus, the experimental result shows that water is more useful than ethanol as the working fluid because of increasing the operational limit within this experimental conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.7 s.178
• /
• pp.1833-1840
• /
• 2000

Commercially pure copper is tested to obtain creep curves at 2500C. Constitutive relations adopting continuum damage mechanics concept is found to be appropriate to model the creep defor mation up to the tertiary stage. Microscopic observation by SEM reveals that creep condition induces cavities and microcracks subsequently. The constitutive equations along with evaluated creep parameters are implemented into finite element analysis code. The analysis reproduces creep curves under step loading as well as constant loading with reasonable accuracy. Distribution and evolution of damage under creep loading are numerically simulated for two different types of notched specimen. Predicted creep life agrees quite well with rupture test results. The influence of mesh size at notch tip on rupture time prediction is studied, and a degree of refinement is suggested for the specific notched specimens.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.53-55
• /
• 1995

This paper presents the characteristics of linear induction motors fed by a voltage source PWM inverter. In the calculation, 2D finite element method is used considering the movement by moving mesh. Integro-differential approach is adopted for the copper loss calculation considering the skin effect.

• Journal of the Mineralogical Society of Korea
• /
• v.28 no.1
• /
• pp.17-28
• /
• 2015

In order to study the mineralogical and chemical characteristics of copper slag, optical microscopy, SEM/EDS, EPMA, AAS and XRD analyses were carried out. In addition, sulfuric acid leaching experiments were performed to investigate the potential of the slag as a copper resource. It was confirmed that fayalite, chromite, bornite and chalcopyrite were contained in the slag. The slag mainly consisted of acicular fayalite and skeletal lath -euhedral chromite crystals. Also a very large amount of bornite and chalcopyrite grains were contained in the slag. The content of Fe and Cu in the slag was 18.37% and 0.93%, respectively. As a result of sulfuric acid leaching experiments, the leaching rates of Cu and Fe were increased through decreasing the slag particle size, increasing the sulfuric acid concentration and the leaching temperature. The maximum efficiency of Cu and Fe leaching were obtained under the conditions of particle size of 32 mesh, sulfuric acid concentration of 2.0 M, and leaching temperature of $60^{\circ}C$. Accordingly, it is expected that the slag could be available as a potential and alternative resource of metallic copper.

• Applied Chemistry for Engineering
• /
• v.8 no.1
• /
• pp.23-28
• /
• 1997

The adsorption characteristics of ammonia-Cu(II) complex on activated carbon were studied. Firstly, the specific surface area of the activated carbon was measured by using the BET adsorption apparatus. Secondly, the characteristics of the removal copper(II) ion from aqueous ammonia solution by forming a complex with ammonia and then by the adsorption of the complex on the activated carbon were studied. It was found that the specific surface area increases with decreasing the mesh number of the activated carbon, and the optimum pH for the adsorption of the Cu(II) ion on she activated carbon was found to be approximately 6. It was also found that the adsorbed Cu(II)-ammonia complexes on the activated carbon in the aqueous ammonia solution have two types, depending on the concentration of the solution ; i.e. $[Cu(NH_3){_2}]^{2+}$and $[Cu(NH_3){_3}]^{2+}$ for $2.25{\times}10^{-4}(mol/{\ell})$and $2.25{\times}10^{-3}(mol/{\ell})$, respectively.

• Solar Energy
• /
• v.12 no.3
• /
• pp.37-46
• /
• 1992

An experimental study was carried out to investigate the performance of a latent heat storage system using paraffin wax as the phase change material. A thermosyphon was employed to transfer heat from the hot ethylene glycol flowing across the evaporator section of the thermosyphon into the wax. In order to increase the effective thermal conductivity of wax, layers of copper wire mesh were immersed in the wax. Experiments were run for volume ratios of 2%, 3%, and 4%, varying mass flow rate of ethylene glycol in each case. Some of the important results are as follows : (1) The wire mesh enhanced the conductive hea transfer and thus, helped even out the temperature distribution in the wax : (2) The increase of the number of layers of wire mesh increased the conduction. However, it also resulted in increasing the resistance to the convective motion of liquefied wax : and (3) There is an optimal number of layers of wire mesh, maximizing the performance of the storage system, which occurred at a volume ratio of $3{\sim}4%$ in the present study.