Performance Of Bilayer Research Articles

Fabrication of Bilayer Fe<sub>2</sub>O<sub>3</sub>/ZnO Photoanode and its Photoelectrochemical Performance

Hematite (Fe2O3) is one of the abundant magnetic materials in nature. Hematite has good absorption ability in the region visible light and good electrochemical stability, which make this material is potential as photoanode for photoelectrochemical (PEC) cells. However, Fe2O3 has some disadvantages such as short hole diffusion length and low hole mobility. Therfore, it is necessarily to combine Fe2O3 with photocatalyst material to improve photoelectrochemical performances. ZnO is ones of photocatalist material with good electron mobility, wide band gaps, cheap and are easily fabricated. The aim of this study is to investigate the performance of bilayer Fe2O3/ZnO as photoanode for photoelectrochemical cell. The bilayer Fe2O3/ZnO was prepared by spin-coating techniques and doctor blade methods. The samples were characterized by X-ray diffarction, and Scanning Electron Microscopy. The performance of photoelectrochemical cell was investigated by Cyclic Voltammetry (CV) under light illumination. The result indicate that bilayer Fe2O3/ZnO has good photoelectrochemical properties.

Dry turning performance of TiN–WSx/TiN hard-lubricious bilayer composite coating

Dry machining is receiving immense attention worldwide to eliminate or minimize the harmful environmental effects of cutting fluids. The present work investigates dry machining performance of a bilayer coating with top-layer of hard-lubricious TiN–WSx, supported by a hard TiN under layer. During dry turning of AISI 1060 steel, the bilayer coated carbide tool registered significantly less cutting forces as compared to its TiN coated counterpart in the cutting velocity range of 77–230 m/min. In prolonged turning test at cutting velocity of 200 m/min, it also exhibited notably higher tool life on the order of 13 and 2.17 times respectively as compared to the uncoated WC and monolayer TiN coated tool. Such improved performance of bilayer coating was found to be associated with its microstructure, mechanical and tribological properties. Existence of lubricious WS2 phase in the composite TiN–WSx layer along with superior coating adhesion and equivalent nanohardness as compared to TiN resulted in low cutting forces. Formation of W–O tribo layer on surface of worn-out coating on flank surface of tool aided in improving tool life during prolonged turning test.

Enhancement of plasmonic transmittance of porous gold thin films via gold/metal oxide bi-layers for solar energy-saving applications

Thin films of noble metals, such as gold, have high visible transparency and infrared reflectance. The former is due to the presence of surface plasmons, and the latter is due to the large density of free electrons. Gold thin films have a transmittance peak at 520 nm, which is closely matched to the maximum emission of solar radiation. These properties have been utilized in several applications, including energy-saving transparent heat mirrors that consist of a bi-layer of a thin gold film over-coated with a dielectric layer. These coatings transmit light and reflect heat. For such an application, the transmittance of the thin gold film needs to be enhanced; this is achieved by the dielectric layer that functions as an antireflective coating. In this work, the dielectrics were metal oxides that are transparent in the visible range. The selection criteria based on the band gap, and refractive index were first imposed to identify potential metal oxides. This resulted in the choice of ten metal oxides (CeO2, HfO2, MoO3, Nb2O5, NiO, SnO2, Ta2O5, TiO2, WO3, and ZrO2). The bi-layer performance was then optimized theoretically. The gold-metal oxide layers were subsequently fabricated, and their optical spectra were measured over the ultraviolet–visible-near infrared ranges. The performance of the heat mirrors was assessed in terms of their visible and solar transmittance and reflectance. A figure of merit was defined to evaluate the suitability of the oxides. The optical properties suggest that tungsten oxide (WO3) is the best oxide; however, hafnium oxide (HfO2) has the best performance for solar energy applications.

Comparative Study of Metal Impregnated Lanthanum Doped Strontium Titanate Anodes and Conventional Nickel Oxide Anode for Solid Oxide Fuel Cell Application

Nickel sintering studies are carried out on La0.3Sr 0.7TiO3+δ (LST) anode backbone impregnated with different quantities of nickel oxide (NiO). It is observed that 4 wt % NiO is sufficient to form a percolated network with low sintering at 800 ˚C using particle migration and coalescence process. Two different mechanisms contributing to sintering process are studied for particle size distribution (PSD). To enhance catalytic activity, cerium oxide (CeO2) is impregnated along with NiO in LST. The performance of bilayer, 4 wt % NiO-6 wt % CeO2-LST/YSZ provided less polarization resistance (Rp) of 0.5 Ω cm2and a maximum power density of 200 mWcm-2 (900 mA cm-2) compared to that without NiO and CeO2 impregnation.

Quasi-static and impact perforation of polymer-metal bi-layer plates by a blunt indenter

The use of polymer layers to alter the impact response of metallic plates has emerged recently as an effective and economical means to enhance perforation resistance. However, the function of the polymer in such laminate systems remains unclear. In this investigation we aim to identify, through systematic experiments, the influence of a polymer layer on the perforation mechanisms and energy absorption of laminated plates. In particular, we consider the combination of a polymer with a thin metallic plate in a bi-layer configuration, subjected to either quasi-static or impact loading by a blunt indenter. Bi-layers are investigated which comprise an aluminium alloy layer (6082-T6) and a polyethylene layer (LDPE, HDPE and UHMWPE). It is found that the energy required to perforate the bi-layer plate can significantly exceed that of the bare metallic substrate (showing the potential for polymer coatings as an effective retro-fit solution) when the polymer is on the impacted face. Furthermore, bi-layer configurations are also shown to outperform the equivalent mass of monolithic metal if the correct thickness ratio of polymer and metal is selected. The effectiveness of a polymer layer in enhancing perforation energy is connected to its large ductility, allowing extensive deformation of the polymer under the indenter, which in turn suppresses plugging and diffuses plastic deformation in the metal layer. In this way the energy absorbed by the metal layer can be maximised. The thickness of the polymer layer is found to be a crucial parameter in maximising the effectiveness of the bi-layer target. An optimum polymer thickness is observed which maximises energy absorption per unit mass of bi-layer target (for a fixed substrate thickness). The synergy between metal and polymer layers also depends on the polymer type and the rate of loading. A polymer with high strain hardening performs best under impact conditions. However, under quasi-static loading, the bi-layer performance is less sensitive to the yield strength and strain hardening of the polymer.

Hydrodynamic and Mass Transfer Performance of Bilayer Fixed Valve Tray

Fixed valve trays have the advantages of low pressure drop, high efficiency, anti-fouling, simple structure, low manufacture cost and long runtime and therefore have been widely used abroad. This paper presents a new bilayer fixed valve (BFV) tray which has some improvements on traditional fixed valve trays. The hydrodynamic and mass transfer performance of BFV tray, sieve tray and F1 valve tray was experimentally studied with air-water-oxygen system in a 1.2m column. The results showed that the BFV tray possesses low pressure drop, high capacity, wide operating range and high efficiency.

Amorphous/crystalline blend effects on the performance of polymer-based photovoltaic cells

Bilayer TiO2/polymer photovoltaic cells are prepared by using regioregular poly（3-hexylthiophene） （P3HT） and branched poly（ethyleneimine） （BPEI） as an additive to P3HT. Influences of BPEI, an amorphous polymer, on the performance of bilayer TiO2/P3HT cells are investigated by means of steady-state current-voltage measurements and dynamic intensity-modulated photovoltage spectroscopy, in combination with differential thermal analysis, UV-vis absorption and photoluminescence spectroscopy. Due to the high crystallinity of P3HT, bilayer TiO2/P3HT cell exhibits a poor performance. As P3HT is blended with BPEI in the weight ratio of WBPEI/P3HT=1％—5％, the performance of the devices is greatly improved; in particular, as WBPEI/P3HT= 1%, the cell exhibits an open-circuit voltage of 0.8V and a short-circuit current of 20μA/cm2. Results show that the influence of BPEI on the cell performance originates from the changed interfacial contact at TiO2/P3HT interface rather than the varied optical properties of P3HT in P3HT-BPEI blend. BPEI imposes two competitive effects on interfacial contact between TiO2 and P3HT, depending on the compositional structure of the blend. On one hand, BPEI improves the interfacial contact by reducing the crystallinity of P3HT and enhancing the interaction between P3HT and TiO2. On the other hand, the interfacial contact will become worse with more BPEI chains accumulating on TiO2 surface. A good contact at TiO2/P3HT interface facilitates the access to a high exciton dissociation efficiency, a long lifetime of photogenerated electrons and further a high device efficiency. The results presented in this paper are expected to provide new insights and a novel strategy for improving the performance of polymer-based photovoltaic cells.