Applied Mechanics and Materials Vols. 284-287

Abstract: Polymeric nanocomposites have gained importance in the material properties to provide enhanced performances such as electrical and mechanical properties. One of the targets in this field is to obtain new materials with improved dielectric properties for High Voltage (HV) insulation application. In general, the good insulator must have low conductivity level. This paper presents the outcome of an experimental study to find the conductivity level of LLDPE-Natural Rubber (NR) compound filled with different amount of nanoparticles of SiO2 and TiO2 by using Polarization and Depolarization Current (PDC) measurement technique. PDC measurement is an efficient and effective insulator diagnostic technique based on time domain measurement to monitor the dielectric behaviour. The experiment was conducted to find PDC pattern and conductivity variations of each new sample. The results show that the addition of SiO2 filler exhibited in less conductivity compared to TiO2 filler with certain percentage. LLDPE-NR/ SiO2 can be a good insulator compared with LLDPE-NR/ TiO2.

Abstract: The influence of flow rotation on the synthesis of carbon nano-structures using rotating opposed flow ethylene diffusion flames and a catalytic Ni substrate was investigated. In the experiments, the flame parameter was kept constant with fuel and oxidizer compositions of 20%C2H2+80%N2 and 40%O2+60%N2 in the upper and lower burners, respectively, whereas the strain rate was varied by adjusting the rotation speed. Stain rate affects carbon nano-structures synthesis either through the residence time of the flow or carbon sources available for the growth of carbon nanotubes (CNTs) and onions. A diffusion flame at low strain rate is stronger than a weak flame at high strain rate and produces more carbon sources because of the longer residence time of the flow. At a higher strain rate, curved and entangled tubular multi-walled CNTs were harvested, however, at a lower strain rate carbon nano-onions (CNOs) were synthesized. It is verified that flow rotation associated with residence time plays an important role in the synthesis of carbon nanostructures.

Abstract: Two sequence-inversed probes were microarrayed on glass slides to study the hybridization efficiency with their DNA targets. A fluorescence laser scanner and an atomic force microscope (AFM) were utilized to investigate the efficiency in different hybridization cases and their corresponding depth changes on the chips. The sequences of two targets were designed to be fully complementary to their shared DNA probe in a coaxial stacking configuration. In other words, after the first DNA target is hybridized (pre-hybridizing) onto the probe, the second one is stacked onto the non-hybridized region of the same probe. The pre-hybridizing and the second DNA targets were distinguished by two distinct fluorescent dyes. The enhancement of the hybridization efficiency was investigated through the comparison between the stacking and individual hybridization configurations. AFM was used to measure the depths of two probes at different steps of hybridization. The results indicated that the depths increased as the hybridization proceeded. Probe#1, pre-hybridizing close to the chip surface, obtained a thicker depth than the other probe pre-hybridizing away from the chip surface, Probe#2. A hypothesis was proposed to explain how the depth variation was associated with the observed hybridization efficiency.

Abstract: In this study, we proposed an anti-reflection (AR) texture constructed with nano-scale silicon dioxide particle dispersed in Accuglass® T-11 solution to form the structure on the glass by two-steps spin coating technique. We demonstrated the transmittance of the glass with AR texture will be enhanced about 2 % under optimal manufactured conditions. And we have proposed the simulated out-door endurance testing of AR texture which can provide the acceptable transmittance at different relative humidity levels. Based on these findings, we believe that the AR texture with SiO2 nanospheres on the cover glass can be useful in the applications of solar cell, thermal collector, and display device under appropriate environmental conditions.

Abstract: This study utilizes radio frequency magnetron sputtering(RF-sputtering) to deposit GZO transparent conductive film and Ti thin film on the same corning glass substrate, then treats GZO/Ti thin film with rapid thermal annealing. The annealing temperature is 300, 500 and 550°C, respectively. Moreover, the effects of process parameters on resistivity and optical properties are investigated. The deposited rate, microstructure, thickness and Optical transmission of Ti:GZO thin film are performed. For example, the thicknesses of films were determined by -step profilometer. The crystalline characteristics of thin films were investigated by X-ray diffraction (XRD). Ga and Ti concentration in ZnO film were determined by energy dispersive X-ray spectroscopy (EDS). The electrical properties of the Ti:GZO thin films were measured by Four point probe. The optical properties of Ti:GZO thin films were examined using UV–vis spectrophotometer. The results show that the transmittance of Ti:GZO thin film exhibited an excellent transparency in the visible light field. The resistivity of Ti:GZO decrease with increasing annealing temperature.

Abstract: The production environment of aerospace industry is make-to-order. Aircraft parts should have higher precision and lightweight to achieve the requirements of safety, payload, and controllability. The composite part has become more important, profitable and value-added in aircraft industry. The main processes of composite parts are prepreg cutting, lay-up, autoclave curing, hand routing and painting. Due to the aerospace composite shop is mixed production line, the parts belong to different customers/ projects that have their own raw materials and curing cycles. The integration of resources from upstream to downstream to meet the demand of each customer/project is critical to shop floor control of composite shop. The purpose of this study is aimed to construct the grouping of curing cycles to simplify the complexity of different customers/ projects, harmonize the production rhythm of all work centers. It is believed that this study can increase the competitive advantages of composite shop in the global aerospace market.

Abstract: In this study, the combined technologies of dual-layer photoresist complimentary lithography (DPCL), inductively coupled plasma-reactive ion etching (ICP-RIE) and laser direct-write lithography (LDL) are applied to produce the submicron patterns on sapphire substrates. The inorganic photoresist has almost no resistance for chlorine containing plasma and aqueous acid etching solution. However, the organic photoresist has high resistance for chlorine containing plasma and aqueous acid etching solution. Moreover, the inorganic photoresist is less etched by oxygen plasma etching process. The organic and inorganic photoresists deposit sequentially into a composite photoresist on a substrate. The DPCL takes advantages of the complementary chemical properties of organic and inorganic photoresists. We fabricated two structures with platform and non-platform structure. The non-platform structure featured structural openings, the top and bottom diameters and the depth are approximately 780 nm, 500 nm and 233 nm, respectively. The platform structure featured structural openings, the top and bottom diameters and the depth are approximately 487 nm, 288 nm and 203 nm, respectively. The precision submicron or nanoscale patterns of large etched area and patterns with high aspect ratio can be quickly produced by this technique. This technology features a low cost but high yield production technology. It has the potential applications in fabrication of micro-/nanostructures and devices for the optoelectronic industry, semiconductor industry and energy industry.

Abstract: LiOH is known to be one of the most efficient CO₂ adsorbent because it reacts with CO₂ to form Li₂CO₃. However, LiOH still suffers from lack of enough hardness for practical use. In this study, various substrates, were modified with LiOH. Their X-ray diffraction patterns were investigated, and LiOH peak was observed from all prepared samples. CO₂ adsorption capacity of each prepared sample was measured by monitoring CO₂ concentration change during the adsorption process under constant CO₂ gas inflow condition. LiOH-modified Al₂O₃ and zeolite 5A showed good CO₂ adsorption performance, while LiOH-modified AC and SiO₂ showed relatively poor CO₂ adsorption. Al₂O₃ and zeolite 5A contains many basic functional groups of Al3+, which promote the neutralization reaction with acidic CO₂. The effect of carrier gas, carrier gas flow rate, initial CO₂ concentration, and amount of LiOH-modified Al₂O₃ loading was investigated. CO2 adsorption performance was better when the carrier gas was N₂, because O₂ competes with CO₂ on LiOH. CO₂ adsorption performance was better with lower carrier gas flow rate, lower initial CO₂ concentration, and less loading of adsorbent due to the increase of contact time and contact points.

Abstract: This In this work, zinc oxide film was deposited onto the SiO₂/Si substrate with low-cost sol-gel spin coating method. Zinc oxide thin film was deposited on the silver interdigit elctrodes for the pH measurement. The surface morphology and microstructures of the deposited zinc oxide films were analyzed by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). Whereas the crystallinity and structure of the zinc oxide films were determined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The measurement at various pH values, which were ±1 above and below of the neutral pH had been conducted with a real time dielectric analyzer measurement. It was observed that the increase in pH would decrease the capacitance of the device.

Abstract: In this study, the performance of nitrification and denitrification were investigated in a sequencing batch biofilm reactor (SBBR) with biodegradable polyurethane foam. The study aimed at solving the shortage of carbon sources for denitrification treating wastewater with a low C/N ratio. Ammonium, nitrite, nitrate, pH and Dissolved oxygen (DO) were carried out to monitor the process of nitrification-denitrification in every cycle. The results showed that Total nitrogen (TN) removal efficiency of 67.5% was achieved during a monitoring period of three months. The SBBR showed good behavior in terms of total nitrogen removal as the biodegradable polymer was an effective substrate providing reducing power for denitrification. According to scanning electron microscope, the biofilm from the inside of the Polyurethane (PU) carriers comprised predominately of small rod-shaped and spherical clusters were dominant, while clusters of filamentous form and few long rod shaped were observed on the surface. The used PU carriers after being washed with distilled water were found some cavities due to corrosion by microorganisms.