Velocity profiles between two baffles in a horizontal circular tube

The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat.The baffles are also an important element inside the heat exchanger.Internal materials influence the flow pattern in the bed.The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube.The velocity of the particles was measured before the baffle and between them in the test tube.
Results show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front baffle.The flows circulate in the front and rear baffles.These flow profiles are related to the Reynolds number（Re） or the flow intensity.The velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front wall.
Swirling flow was employed in this study,which was produced using tangential velocities at the inlet.At the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without swirl.However,velocities between two baffles are not much different from those without swirl.     

Improvement of cycle behaviour of SiO/C anode composite by thermochemically generated Li4SiO4 inert phase for lithium batteries

A new anode composite material is prepared by thermal treatment of a blend made of silicon monoxide (SiO) and lithium hydroxide (LiOH) at 550 °C followed by ball milling with graphite. X-ray diffraction pattern confirms the presence of Li₄SiO₄ in the thermally treated (SiO + LiOH) material. The electrode appears to be smooth and glassy as evident from observation with a scanning electron microscope (SEM), possibly due to the presence of nano-silicon and Li₄SiO₄ particles, and exhibits superior performance with a charge capacity of ∼333 mAh g⁻¹ at the 100th cycle with a low-capacity fade on cycling. Cyclic voltammograms of the electrode predict high power capability. On the other hand, the electrode comprising of only SiO and C prepared through ball milling, devoid of Li₄SiO_4, shows hard crust particulates in the electrode exhibiting low charge–discharge capacities with cycling.     

Viscoplastic parameter identification of temperature‐dependent mechanical behavior of modified polyphenylene oxide polymers

Modified polyphenylene oxide (MPPO) is a widely known thermoplastic polymer and is extensively utilized for weight reduction of automobiles since it possesses outstanding mechanical properties, such as resistance and toughness. In this study, the viscoplastic behaviors of MPPO with respect to changes in temperature were identified through an approximate optimization method. For this work, parameter studies were conducted with a tensile simulation of the MPPO polymer, in accordance with the modified two‐layer viscoplastic material parameters and the suggested shift parameter. The sensitivity tendency of the force‐displacement curves was captured in accordance with the material parameters. Computational experiments for obtaining calibration error data were performed using the material parameters based on interior central composite design. Surrogate models of root mean square error relative to force and displacement were generated using the response surface method. The accuracy of the surrogate models was evaluated with R‐square. Optimization for obtaining the material parameters was performed using the non‐dominant sorting genetic algorithm‐II. The results showed that the calibration error from the finite element analysis was minimized and agreed with experimental data. POLYM. ENG. SCI., 59:E200–E211, 2019. © 2018 Society of Plastics Engineers     

Development of measurement technique of explosive flame using an optical measurement method

Journal of Mechanical Science and Technology - It is essential in weapons systems to understand how much explosive power is applied according to various chemicals and methods of the explosion. In...     

Development of interpolation-free PTV

Journal of Mechanical Science and Technology - A new particle tracking velocimetry (PTV) algorithm, which has no interpolation process requirement, has been constructed. An affine transformation...     

Fine metal mask material and manufacturing process for high‐resolution active‐matrix organic light‐emitting diode displays

Manufacturing fine metal mask (FMM) is one of the biggest hurdles to realize the ultra‐high definition (UHD) grade AMOLED displays for smartphone and augmented reality (AR). We have developed the state‐of‐the‐art material and processing technology to achieve 800ppi or higher‐resolution FMMs. The Invar thinning and the thermal damage‐free laser ablation process realized us achieving the FMM for UHD displays.     

Characterization of chemically modified wood fibers using FTIR spectroscopy for biocomposites

Chemical modifications of wood fibers (Lignocel® C120) were performed for biocomposite applications, and chemically modified wood fibers were analyzed by FTIR spectroscopy. NaOH treatment showed band shifts from Cell‐I to Cell‐II in FTIR spectra from 2902 cm^?1, 1425 cm^?1, 1163 cm^?1, 983 cm^?1, and 897 cm^?1 to 2894 cm^?1, 1420 cm^?1, 1161 cm^?1, 993 cm^?1, and 895 cm^?1 and the change in peak height at 1111 cm^?1 and 1059 cm^?1 assigned for Cell‐I structure. Silane treatment showed peak changes at 1200 cm^?1 assigned as Si? O? C band, at 765 cm^?1 assigned as Si? C symmetric stretching bond, at 700 cm^?1 assigned as Si? O? Si symmetric stretching, and at 465 cm^?1 assigned as Si? O? C asymmetric bending. Benzoyl treatment resulted in an increase in the carbonyl stretching absorption at 1723 cm^?1 and in band characteristics of aromatic rings (1604 cm^?1 and 710 cm^?1) and a strong absorption at 1272 cm^?1 for C? O band in aromatic ring. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The effect of through plane pore gradient GDL on the water distribution of PEMFC

The effect of through plane pore gradient of gas diffusion layer (GDL) on the performance of Polymer Electrolyte Membrane Fuel Cell is investigated experimentally. The performance with GDLs having no, medium and high pore gradient are compared at 2 different relative humidity (RH) conditions. The medium pore gradient GDL shows generally the best performance in both RH conditions. The performance difference is analyzed based on the water distribution. The water distribution is measured through the X-ray visualization. The amount of water is reduced with the pore gradient GDL. This change reduces the concentration over-potential, and thereby increases the performance at high RH condition. However, the reduction of liquid water results in dehydration of the membrane at low RH condition. This makes lower performance with high pore gradient. The highest performance is not matched with the highest pore gradient. The effect of pore gradient is distinct when water exists sufficiently.     

DEVELOPMENT OF AN ADAPTIVE STEREOSCOPIC-PIV SYSTEM FOR ANALYSIS OF THE FLOW-STRUCTURE INTERACTIONS (FSI) OF AIR-LIFTED BODIES

An adaptive stereoscopic-PIV system has been constructed for flow analyses around a cylinder body (length = 60 mm, diameter = 10 mm, polystyrene). The body is floated by the swirling flows in a vertical pipe with a length of 1100 mm and an inner diameter of 100 mm. Four optical sensors (LEDs) were installed onto the pipe wall to detect the posture of the cylinder body. The constructed stereoscopic-PIV system is activated by the signals of the optical sensors when the cylinder is in the upright posture. The measurement system consists of two cameras, a Nd-Yag laser, and a host computer. Flow characteristics around the floating cylinder body and the motional characteristics of the body itself are investigated when the body is in the upright posture. It has been verified that the motion of the floating cylinder becomes stable when the azimuthal velocity component (W component) of the swirl flow is maintained at stable states.     

Cathodic shift and improved photocurrent performance of cost-effective Fe2O3 photoanodes

We successfully fabricated cost-effective and efficient pulse electrodeposited Fe₂O₃ photoanodes for PEC water splitting application. Surface modifications of Fe₂O₃ by oxygen evolution catalysts like cobalt phosphate (Co–Pi), a monoclinic BiVO₄ or both showed cathodic/anodic shift in photocurrent with significantly improved photo-response.