ATR FT-IR absorption enhancement of a thin film under the photon-tunneling condition

A simple, yet very powerful technique for the spectral acquisition of an extremely thin film with enhanced absorption was explored. An infrared absorption of an extremely thin film confined between media of high refractive indices was greater than that of its bulk when the spectrum was acquired under the attenuated total reflection (ATR) condition with parallel (p) polarized radiation. The absorption enhancement was not observed under perpendicular (s) polarized radiation. Theoretical investigations indicated that the absorption enhancement was proportional to the integration of the mean square evanescent field within the film. The field integration under p-polarized radiation increased, while that under s-polarized radiation decreased as the thickness of the confined film became thinner. The maximum enhancement was observed when the film was sufficiently thinner than the penetration depth. The phenomena were experimentally investigated, and the results agreed very well with theoretical predictions.

UV absorption property of bamboo

This article describes ultra violet (UV) light shielding behaviour of Australian grown bamboo (Phyllostachys pubescens). Optical reflectance showed that untreated bamboo plant has UV absorption properties. To reveal the origin of the UV absorption property, its chemical components were extracted using several polar and non-polar solvents. The extracts in most of the polar and non-polar solvents showed UV absorption property. Protic polar solvents showed better ability to extract UV absorbing chemicals than aprotic and non-polar solvents, except hexane. The chemical components of bamboo were analysed by FT-IR spectroscopy and the findings were correlated with the UV absorbance characteristics. The results confirmed that the UV absorption ability of bamboo originates from nothing but lignin. It is thus indicated that the conventional methods to manufacture bamboo fibres, such as complete degumming or viscose methods, that involve the removal of lignin, cannot retain the unique UV absorption property of bamboo plant in bamboo fibres.

Detection of curved edges at subpixel accuracy using deformable models

One approach to the detection of curves at subpixel accuracy involves the reconstruction of such features from subpixel edge data points. A new technique is presented for reconstructing and segmenting curves with subpixel accuracy using deformable models. A curve is represented as a set of interconnected Hermite splines forming a snake generated from the subpixel edge information that minimizes the global energy functional integral over the set. While previous work on the minimization was mostly based on the Euler-Lagrange transformation, the authors use the finite element method to solve the energy minimization equation. The advantages of this approach over the Euler-Lagrange transformation approach are that the method is straightforward, leads to positive m-diagonal symmetric matrices, and has the ability to cope with irregular geometries such as junctions and corners. The energy functional integral solved using this method can also be used to segment the features by searching for the location of the maxima of the first derivative of the energy over the elementary curve set.

Modeling edges at subpixel accuracy using the local energy approach

In this paper we described new technique for 1-D and 2-D edge feature extraction to subpixel accuracy using edge models and the local energy approach. A candidate edge is modeled as one of a number of parametric edge models, and the fit is refined by a least-squared error fitting technique.

Impact response and energy absorption of aluminium foam-filled tubes

The effect of foam fillers on the impact behaviour and energy absorption of an aluminium tube is investigated. Both experimental test and computational simulation are employed in current study. For comparison, hollow tubes and foams are also tested, respectively. Foam filler is found to be ineffective in increasing the crushing loads of the composite tubes over the simple superposition of the crushing loads of hollow tube and foam. Also, foam filler increases the tendency for the concertina mode of folding. The foam fillers of tubes additionally result in increasing the SAE values over those of hollow tubes.

Seagrass patch size affects fish responses to edges

1. Patch area and proximity of patch edge can influence ecological processes across patchy landscapes and may interact with each other. Different patch sizes have different amounts of core habitat, potentially affecting animal abundances at the edge and middle of patches. In this study, we tested if edge effects varied with patch size.

2. Fish were sampled in 10 various-sized seagrass patches (114–5934 m²) using a small (0·5 m²) push net in three positions within each patch: the seagrass edge, 2 m into a patch and in the middle of a patch.

3. The two most common species showed an interaction between patch size and the edge–interior difference in abundance. In the smallest patches, pipefish (Stigmatopora nigra) were at similar densities at the edge and interior, but with increasing patch size, the density at the edge habitat increased. For gobies (Nesogobius maccullochi), the pattern was exactly the opposite.

4. This is the first example from a marine system of how patch size can influence the magnitude and pattern of edge effects.

5. Both patch area and edge effects need to be considered in the development of conservation and management strategies for seagrass habitats.

Energy absorption behaviour of rapidly manufactured carbon/epoxy and glass/polypropylene structures

In this thesis the crashworthiness of composite tubular structures was investigated along with the property structure relationships of a glass/polypropylene material. The energy absorption capacity of tubular structures in a number of different testing configurations was made. Two materials; carbon/epoxy pre-preg and a glass/polypropylene dry pre-preg were investigated.