An efficient approach for face recognition based on common eigenvalues

In this paper, a simple technique is proposed for face recognition among many human faces. It is based on the polynomial coefficients, covariance matrix and algorithm on common eigenvalues. The main advantage of the proposed approach is that the identification of similarity between human faces is carried out without computing actual eigenvalues and eigenvectors. A symmetric matrix is calculated using the polynomial coefficients-based companion matrices of two compared images. The nullity of a calculated symmetric matrix is used as similarity measure for face recognition. The value of nullity is very small for dissimilar images and distinctly large for similar face images. The feasibility of the propose approach is demonstrated on three face databases, i.e., the ORL database, the Yale database B and the FERET database. Experimental results have shown the effectiveness of the proposed approach for feature extraction and classification of the face images having large variation in pose and illumination.     

Tailoring new bisphenol a ethoxylated shape memory polyurethanes

Shape memory polyurethanes (SMPUs) have generated great attention because of their unique properties. These properties are result of a particular molecular structure consisting of flexible molecular chains with low glass transition temperatures alternating with hard urethane segments. In this field, bisphenol A (BA) has been used for a long time as chain extender due to the good properties of the obtained SPMU materials. Nevertheless, the high toxicity of this compound has caused a high decrease on its use. For this reason, it has been selected a lower toxicity compound, bisphenol A ethoxylate (BAE). In this work, it is described a new SMPUs based on BAE and the influence of the hard segment on the thermo-mechanical properties and shape memory capacity. For that, both the proportion of the components and the diisocyanate employed (2,4-toluene diisocyanate (TDI), 4,4′-methylene bis(phenylisocyanate) (MDI) or a TDI/MDI mixture) have been modified. Then, depending on the molecular architecture achieved, the polyurethanes present different properties, which were studied by different techniques, such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic-mechanical thermal analysis (DMTA). It has been observed that glass transition temperature (T_g) increases as the hard phase content in the PU samples increases. In addition, T_g-MDI > T_g-MDI-TDI > T_g-TDI, so it is possible to control the T_g of the material, that is, shape memory transition temperature varying the diisocyanate. Finally, the shape memory capacity of the PUs was evaluated by thermo-mechanical analysis (TMA). All the synthesized PUs have shown good shape memory effect with fixation ratios up to 80% and recovery ratios close to 100%.     

Homogeneous asymmetric hydrogenation ofo-chloroacetophenone to enantiomerically pureo-chloro-(1-phenyl)ethanol catalyzed by BINAP-Ru(II) complex

The BINAP-Ru(II) catalyst (2,2-bis(diphenylphosphino)-1,1-binaphthyl)chloro(p-cymene)rutheniun chloride is found to be highly active and enantioselective for homogeneous asymmetric hydrogenation of o-chloroacetophenone to optically pureo-chloro-(1-phenyl)ethanol. In contrast to results of Noyori and coworkers, no organic and inorganic bases are required to obtain high activities and enantioselectivities     

Reinterpretable Imager: Towards Variable Post‐Capture Space,Angle and Time Resolution in Photography

We describe a novel multiplexing approach to achieve tradeoffs in space, angle and time resolution in photography. We explore the problem of mapping useful subsets of time‐varying 4D lightfields in a single snapshot. Our design is based on using a dynamic mask in the aperture and a static mask close to the sensor. The key idea is to exploit scene‐specific redundancy along spatial, angular and temporal dimensions and to provide a programmable or variable resolution tradeoff among these dimensions. This allows a user to reinterpret the single captured photo as either a high spatial resolution image, a refocusable image stack or a video for different parts of the scene in post‐processing. A lightfield camera or a video camera forces a‐priori choice in space‐angle‐time resolution. We demonstrate a single prototype which provides flexible post‐capture abilities not possible using either a single‐shot lightfield camera or a multi‐frame video camera. We show several novel results including digital refocusing on objects moving in depth and capturing multiple facial expressions in a single photo.     

Preservation of strawberries by modified atmosphere packages with other treatments

The impact of modified atmosphere packaging (MAP), in combination with ozone treatment and an edible film coating, on the preservation of strawberries was studied. A combination of 2.5% O₂ with 15% CO₂ was the optimum gas composition for the MAP of strawberries and prolonged shelf‐life by 4–6 days. When the strawberries were pre‐treated with a 4.3 mg/m³ ozone water dip and an edible coating prior to packaging, the shelf‐life was extended to 8–10 days. The results showed that two treatments [No.1: polyvinyl alcohol 134 (2%); monostearatacylglycerol (0.5%); phytic acid (0.05%); sorbitol (0.05%); sodium alginate (0.1%); absolute alcohol (8%): No.2: polyvinyl alcohol 134(1%); soluble starch (1%); glucose (1%); sucrose (1%); sodium alginate (0.1%); sorbitol (0.05%)] gave the best effects on strawberry quality and shelf‐life. All treatments (Nos 1–4) were obviously superior to check experiments for soluble sugar, ascorbic acid, acidity and anthocyanin. Furthermore, the treatments gave superior results for browning index, commodity ratio and permeability of the cell membrane. Copyright © 2006 John Wiley & Sons, Ltd.     

TiO2 nanoparticle embedded nitrogen doped electrospun helical carbon nanofiber-carbon nanotube hybrid anode for lithium-ion batteries

TiO₂ nanoparticles decorated nitrogen (N) doped helical carbon nanofiber (CNF)-carbon nanotube (CNT) hybrid material is prepared by low-cost electrospinning technique followed by hydrothermal method. Morphological investigations establish helical structure of CNFs with hierarchical growth of CNTs around CNFs. The hybrid material shows a high specific surface area of 295.17 m² g^?1 with nanoporous structure. X-ray photoelectron spectroscopic studies establish Ti–O–C/Ti–C bond mediated charge transfer channel between TiO₂ nanoparticles and carbon structures with the success of N doping in CNFs. The electrospun hybrid material delivered high reversible charge capacities of 316 mAh g^?1 (100th cycle) and 244 mAh g^?1 (100th cycle) at a current density of 75 mA g^?1 and 186 mA g^?1 respectively. The charge capacities obtained for different applied current densities are higher than the conventional graphitic microporous microbeads anode. Results indicate that the hybrid material reported here shows high performance compare to graphite for LIBs.