Full-field vibrometry with digital Fresnel holography

A setup that permits full-field vibration amplitude and phase retrieval with digital Fresnel holography is presented. Full reconstruction of the vibration is achieved with a three-step stroboscopic holographic recording, and an extraction algorithm is proposed. The finite temporal width of the illuminating light is considered in an investigation of the distortion of the measured amplitude and phase. In particular, a theoretical analysis is proposed and compared with numerical simulations that show good agreement. Experimental results are presented for a loudspeaker under sinusoidal excitation; the mean quadratic velocity extracted from amplitude evaluation under two different measuring conditions is presented. Comparison with time averaging validates the full-field vibrometer.     

Genetic transformation of Brevibacterium linens strains producing high amounts of diverse sulphur compounds

By its numerous properties and importance in cheese technology (production of colour, flavour, bacteriocins and resistance to salt) Brevibacterium linens is a major cheese ripening bacteria. However, the genetic approach of such biological functions has been hindered, up to now, by the lack of tools necessary to realise genetic modifications in this species. Our objective was to demonstrate that it is possible to genetically modify several strains exhibiting interesting technological properties, especially the production of sulphur compounds. We worked with a phenotypically and genetically diverse collection of 11 strains. We genetically transformed several Brevi. linens with acceptable rates with plasmids classically used to transform lactic acid bacteria and other Gram+ bacteria. These results open up new prospects to investigate the most interesting Brevi. linens metabolic pathways both at the biochemical and genetic level.     

Heat Capacity of Sodium Silicate Liquids

Drop calorimetry measurements for four Na₂0-Si0₂ liquids indicate that, to within ±0.5%, the heat capacities are temperature-independent between 900 and 1800 K and additive functions of composition for liquids containing from 50 to 100 mol% Si0₂. In this composition interval, the partial molar heat capacities of Si0₂ and Na₂0 are 81.37 and 100.6 J /mole-K, respectively.     

Absorbent polyvinyl alcohol–sodium carboxymethyl cellulose hydrogels for propolis delivery in wound healing applications

Second degree burns require dressings to heal. The ideal dressing should keep a moist environment, have low cost, be elastic and have a bactericidal effect. The potential of PVA‐NaCMC (sodium carboxymethyl cellulose) gels to combine the mechanical and swelling properties of PVA with the flexibility and high water uptake of NaCMC and the antimicrobial characteristics of propolis is investigated. The freeze‐thawed gels were characterized by FTIR and DSC. Their swelling behavior, their mechanical response, the delivery of active compounds and their antimicrobial properties were also determined. The main findings of the FTIR analysis were that no chemical bonding occurred between the materials. The DSC analysis revealed that the addition of NaCMC to PVA lowered the PVA crystallinity, as did the addition of propolis, leading to a more deformable gel (as can be observed from the tensile tests results). This also resulted in a higher rate of delivery of active compounds, higher weight loss and higher fluid uptake than comparable PVA‐propolis systems, as shown by the swelling tests and by the propolis delivery tests. Samples with 15% propolis content or more inhibited S. aureus colonies with 80% reduction, and are therefore highly absorbent and compliant antimicrobial gels for wound healing. POLYM. ENG. SCI., 57:1224–1233, 2017. © 2017 Society of Plastics Engineers     

Cover Image,Volume 92, Issue 5

The cover image, by Manal Ali et al., is based on the Research Article Potential of using non‐inoculated self‐aerated immobilized biomass reactor for post‐treatment of upflow anaerobic staged reactor treating high strength industrial wastewater, DOI: 10.1002/jctb.5082 .

     

Dense on Porous Solid LATP Electrolyte System: Preparation and Conductivity Measurement

A dense membrane of lithium aluminum titanium phosphate Li_1+xAl_xTi_2?x(PO₄)₃, x = 0.3 (LATP) is deposited on a porous LATP substrate via wet chemistry. In the polymerized complex process, phosphate precursors with different active groups and steric hindrance are selected to tune precursor's reactivity. Rheological studies and microstructural observations lead to the selection of an LATP powder slurry charged with lithium, aluminum, titanium, and phosphate ion precursors. The optimized formulation is impregnated into a porous LATP substrate. After thermal treatment, dense LATP membranes on top of a porous LATP substrate are obtained with conductivities as high as 3 × 10^?4 S/cm for the dense part, the porous part acting as a mechanical support. An original Van der Pauw impedance setup is validated for the measurement of the ionic conductivity of such dense/porous systems.     

Extrinsic calibration of heterogeneous cameras by line images

The extrinsic calibration refers to determining the relative pose of cameras. Most of the approaches for cameras with non-overlapping fields of view (FOV) are based on mirror reflection, object tracking or rigidity constraint of stereo systems whereas cameras with overlapping FOV can be calibrated using structure from motion solutions. We propose an extrinsic calibration method within structure from motion framework for cameras with overlapping FOV and its extension to cameras with partially non-overlapping FOV. Recently, omnidirectional vision has become a popular topic in computer vision as an omnidirectional camera can cover large FOV in one image. Combining the good resolution of perspective cameras and the wide observation angle of omnidirectional cameras has been an attractive trend in multi-camera system. For this reason, we present an approach which is applicable to heterogeneous types of vision sensors. Moreover, this method utilizes images of lines as these features possess several advantageous characteristics over point features, especially in urban environment. The calibration consists of a linear estimation of orientation and position of cameras and optionally bundle adjustment to refine the extrinsic parameters.