Mechanical and thermal behavior of non-crimp glass fiber reinforced layered clay/epoxy nanocomposites

Mechanical and thermal properties of non-crimp glass fiber reinforced clay/epoxy nanocomposites were investigated. Clay/epoxy nanocomposite systems were prepared to use as the matrix material for composite laminates. X-ray diffraction results obtained from natural and modified clays indicated that intergallery spacing of the layered clay increases with surface treatment. Tensile tests indicated that clay loading has minor effect on the tensile properties. Flexural properties of laminates were improved by clay addition due to the improved interface between glass fibers and epoxy. Differential scanning calorimetry (DSC) results showed that the modified clay particles affected the glass transition temperatures (T_g) of the nanocomposites. Incorporation of surface treated clay particles increased the dynamic mechanical properties of nanocomposite laminates. It was found that the flame resistance of composites was improved significantly by clay addition into the epoxy matrix.     

Distributed power-source-aware routing in wireless sensor networks

Wireless Networks - Although many applications use battery-powered sensor nodes, in some applications battery- and mains-powered nodes coexist. In this paper, we present a distributed algorithm...     

The effects of growth conditions on the surface properties and photocatalytic activities of anatase TiO<Subscript>2</Subscript> films prepared via electrochemical anodizing and annealing methods

In the present work, nanostructured TiO₂ films were prepared by electrochemical anodization process of titanium in fluoride-containing electrolytes using an innovative approach. After anodization, the TiO₂ films were annealed at 480?°C for 2 h in air in order to acquire anatase phase transformation and increase its crystallinity. The effects of anodization voltage, electrolyte concentration and anodization time on the formation of TiO₂ films and the photocatalytic degradation of methylene blue (MB) were discussed in details. The phase structure and surface morphology of the samples characterized by means of X-ray diffraction and scanning electron microscope. The as-prepared nanostructured TiO₂ film anodized in 0.5% HF electrolyte at 15 V for 240 min showed excellent photocatalytic degradation of MB and is promising for environmental purification.     

Journal Bearing Response to Excitation and Behavior in the Unstable Region

Three types of journal bearing of circular bore, elliptical, and offset-halves designs were subjected to excitation tests over a wide range of frequency. It is shown that, in the stable region of operation, the amplitude of the response correlates reasonably well with the solutions of linear theory. The response was found to peak (strongly in some cases) at excitation frequencies in the range 0.43 to 0.75 of the shaft running speed, depending on design and distance of the operating point from the instability threshold. These observed natural frequencies were found to correlate well with linear theory solutions for lower range frequency values up to about 0.65. At higher predicted natural frequencies, the observed resonance was less than the theoretical solutions.

Little is known of bearing behavior beyond the threshold of stability. It is shown experimentally that limit cycle motion occurs in the unstable region. The orbit size can be quite small, depending on preload and other design factors. The orbit size tends to increase with distance from the instability threshold.     

Recognition of fabric weave patterns using optical coherence tomography

Traditional methods involve extracting individual warp or weft yarns from the fabric in order to identify the weave repeat manually. This process can become tedious due to its manual nature. Therefore, automatic methods capable of identifying woven fabric repeat are utilized. These methods in general require complex algorithms and calculations. Optical coherence tomography (OCT) is a nondestructive and noncontact technique that allows high-resolution imaging. This paper describes the application of spectral domain optical coherence tomography imaging technique for identifying woven fabric repeat. We present the OCT scans of fabrics from which the weave matrixes were identified. We conclude that optical coherence tomography can be used to automatically recognize fabric weave patterns.