Vibrational energy scavenging with Si technology electromagnetic inertial microgenerators

In this work, we present the design and optimization of an electromagnetic inertial microgenerator for energy scavenging applications, compatible with Si technology. It consists of a fixed micromachined coil and a movable magnet (inertial mass) mounted on a resonant structure (Kapton^® membrane). The modeling of the device, based on a velocity damped resonator, has allowed to make a quantitative analysis of the capabilities of this simple device structure for the development of power generators for autonomous microsystem applications. The characterization of a first (not optimized) prototype has allowed the validation of the model, which is then used as a roadmap for a number of optimizations for the final device design. For this design, the model developed shows the possibility to achieve power levels up to hundreds of μW’s, with voltage levels compatible with the requirements of standard rectifying circuits.     

Two Triangulation Methods Based on Edge Refinement

In this paper two curvature adaptive methods of surface triangulation are presented. Both methods are based on edge refinement to obtain a triangulation compatible with the curvature requirements. The first method applies an incremental and constrained Delaunay triangulation and uses curvature bounds to determine if an edge of the triangulation is admissible. The second method uses this function also in the edge refinement process, i.e. in the computation of the location of a refining point, and in the re-triangulation needed after the insertion of this refining point. Results are presented, comparing both approaches.     

Anaerobic Palladium‐Catalyzed Chemoselective Oxidation of Allylic and Benzylic Alcohols with α‐Bromo Sulfoxide as a Co‐oxidant

A chemoselective palladium‐catalyzed anaerobic oxidation of allylic and benzylic alcohols using an α‐bromo sulfoxide as a co‐oxidant is described for the first time. The catalyst system is simple and has a long life because of the allowance of phosphane ligands under the non‐aerobic conditions. The advantages of the described method include no overoxidation of primary alcohols to carboxylic acids because of the mild conditions applied, the tolerance of oxygen‐sensitive functionalities such as a carbon‐carbon double bond, an organothio group, or a diorganoamino group and the effective preparation of α,β‐unsaturated aldehydes and ketones, resulting from the oxidation of primary and secondary allylic alcohols, since a competitive Heck reaction with the co‐oxidant does not occur.     

Frequency dispersion model of the complex permeability of soft ferrites in the microwave frequency range

The complex permeability of Cu-doped nickel-zinc polycrystalline ferrites is strongly dependent on microstructure, particularly, on relative density () and average grain size (). In this study, a mathematical model, able to fit the measured magnetic permeability spectra from 10⁶ to 10⁹ Hz, is proposed and validated for a width range of average grain sizes (3.40–23.15 μm) and relative densities (0.83–0.96). To the authors’ knowledge, domain-wall motion and spin rotation contributions to magnetic permeability have been integrated jointly with the microstructure for the first time in the proposed model, highlighting the relative influence of each magnetizing mechanism and microstructure on the magnetic permeability at different angular frequencies.     

Square wave voltcoulometry: a tool for the study of strongly adsorbed redox molecules

A new multipotential pulse technique called square wave voltcoulometry (SWVC), based on the analysis of the difference of converted charge signals obtained between two successive half-cycles when a square wave potential is applied, is developed to study charge-transfer processes taking place in electroactive monolayers. The use of SWVC presents the advantage of giving rise to a peak-shaped response, which evolves to a charge plateau at high square wave pulse amplitudes, from which the total surface excess and the formal potential can be immediately measured for quasi-reversible and reversible processes. This characteristic represents its main advantage versus other multipotential step techniques, which lead to a negligible current under reversible conditions. The formal potential of the electroactive systems can be measured from the peak potential of the SWVC curves, even for quasi-reversible behavior. Moreover, the non-faradic effects on the response can be easily evaluated and avoided as is demonstrated in this paper. Experimental verification of the theoretical predictions is given for reversible and quasi-reversible systems.     

Symbiotic human–robot collaborative approach for increased productivity and enhanced safety in the aerospace manufacturing industry

The International Journal of Advanced Manufacturing Technology - Robots are perfect substitutes for skilled workforce on some repeatable, general, and strategically important tasks, but this...     

Handover defects: comparison of construction and post-handover housing defects

Although inspections occur during construction or at handover, customers do not normally participate. This situation creates a gap between the quality perceived by both contractors and customers. An analysis of 52 552 handover defects in 2179 flats in Spain is presented which identified their nature, the building element and trade where these defects are located. These results are compared with previous studies that analysed defects detected during the construction stage and those that remain after handing over the building to the client. The research reveals that structural defects are resolved during construction due to existing quality standards. However, other aesthetic and functional defects remain and/or arise at handover. Some defects are not resolved until customers complain after they first occupy the dwelling. Many functional defects arise due to the lack of involvement of end users in the early project stages.