Kung-Hsu Hou

The friction and wear of Ni–P–PTFE composite deposits under water lubrication

Abstract In this study, it is first attempted to evaluate the performance of Ni–P–PTFE material (manufactured through electroless deposition process) on water lubrication system. In addition, the overall performance of water lubrication produced by the coupling of hydrophilic and hydrophobic materials under higher load condition is also investigated. It shows that the friction coefficient and wear are strongly related to the wettability of coupling material. Ni–P–PTFE material can provide stronger property together with the hydrophobic/hydrophilic consideration; it enables us to decrease the wear loss.

Analysis of the Corrosion Behavior of Al Alloy Bipolar Plate for Proton Exchange Membrane Fuel Cell (PEMFC) Under Operating Thermal Conditions

The durability and efficiency of proton exchange membrane (PEM) fuel cell must meet the demanding requirements before its commercialization. Based on this consideration, the chronological acidity change of proton exchange membrane fuel cell (PEMFC) water and the corrosion of aluminum bipolar plate are investigated in this paper. Two operating factors, cell temperature and fuel gas temperature, and two temperature levels, i.e., 30°C and 90°C, are designed for the experiments. The fully humidified feeding flows rates are oxygen gas (140 sccm) at the cathode side and hydrogen gas (210 sccm) at the anode side. The constant current density test is set to 1200 mA/cm2. Characteristics of product water that drained from the PEMFC cathode outlet are measured by a pH meter in a real-time process. The chronological water acidity varied case by case, and its pH value ranged from 3.5 to 7. Abundant free radicals formed easily when the cell temperature is operated at 90°C, and it enhances the acidity of PEMFC water. The microstructure of the corrosive surface is also observed by a scanning electron microscope (JSM series model number 6500F, JEOL Inc.) equipped with an energy dispersive X-ray spectroscopy (EDAX) system.

Helical-Cathode Bulb-Shaped Field Emission Lamps Using Carbon Nanocoil Electron Emitters

Bulb-shaped field emission lamps (FELs) with a helical cathode filament were simulated and fabricated in this research. The light bulbs comprised a helical stainless steel filament cathode grown with carbon nano-coils (CNCs) and an Al anode deposited on the bottom hemisphere of a 60-mm-diameter glass bulb. White light was generated when the field-emitted electrons bombarded a layer of three-color phosphor coated on the anode. A numerical simulation model for the helical-cathode FELs was constructed, and the field emission (FE) performance was carefully studied. Due to the screening effect, the electric field strength as well as the FE current density on the inner side of the helix dramatically decreased with decreasing helical pitch. Real FELs using cathodes with various helical radii and pitches were fabricated and their FE currents were measured. The theoretical and experimental results were in good agreement. A maximum total FE current was found at a pitch of 16 mm (helical radius = 2 mm), where the optimum trade-off between a large total surface area and a small screening effect was obtained. The optimized FEL showed a total luminous flux of about 220 lm at an applied voltage of 8 kV and a color rendering index of 94. Compared to a straight filament cathode, a helical cathode offered a higher total FE current or, alternatively, a lower current density and a longer cathode life, if we fix the total current by using a lower voltage.

Modelling and simulation of power controllable field-emission lamps using carbon nano coil cathodes

In this paper, we demonstrate an easy way to fabricate the power controllable field emission lamps by computing simulation. Based on our previous research, we use SolidWorks® to build a three dimension model and using Comsol Multiphysics 4.1a to calculate the electric field distribution on a straight 304 stainless steel filament with 1mm radius cathode and on it we cut a notch with various lengths. Simulation results show that the electric field on the notch is increased with notch length. By adjust the notch length on the cathode; we can control the power of the field emission lamps.