Application of Frustrated Total Internal Reflection of Millimeter Waves for Detection and Evaluation of Disbonds in Dielectric Joints

Millimeter waves penetrate inside of low loss dielectric materials and they are sensitive to the presence of internal interfaces and nonuniformities. This allows millimeter wave nondestructive inspection techniques to be utilized for inspecting dielectric composite structures. A disbond (a thin and extended airgap) in structures possessing adhesively bonded joints with complex geometries is commonly difficult to inspect. In this letter, we demonstrate the operational principle and the useful features of a millimeter wave technique, employing a frustrated total internal reflection of signals transmitted and received by dielectric waveguide probes for detecting and evaluating disbonds in such joints

Thermo-Mechanical and Morphological Properties of Polymer Composites Reinforced by Natural Fibers Derived from Wet Blue Leather Wastes: A Comparative Study

The present work investigated the possibility to use wet blue (WB) leather wastes as natural reinforcing fibers within different polymer matrices. After their preparation and characterization, WB fibers were melt-mixed at 10 wt.% with poly(lactic acid) (PLA), polyamide 12 (PA12), thermoplastic elastomer (TPE), and thermoplastic polyurethane (TPU), and the obtained samples were subjected to rheological, thermal, thermo-mechanical, and viscoelastic analyses. In parallel, morphological properties such as fiber distribution and dispersion, fiber–matrix adhesion, and fiber exfoliation phenomena were analyzed through a scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) to evaluate the relationship between the compounding process, mechanical responses, and morphological parameters. The PLA-based composite exhibited the best results since the Young modulus (+18%), tensile strength (+1.5%), impact (+10%), and creep (+5%) resistance were simultaneously enhanced by the addition of WB fibers, which were well dispersed and distributed in and significantly branched and interlocked with the polymer matrix. PA12- and TPU-based formulations showed a positive behavior (around +47% of the Young modulus and +40% of creep resistance) even if the not-optimal fiber–matrix adhesion and/or the poor de-fibration of WB slightly lowered the tensile strength and elongation at break. Finally, the TPE-based sample exhibited the worst performance because of the poor affinity between hydrophilic WB fibers and the hydrophobic polymer matrix

Thermal and UV aging of polypropylene stabilized by wine seeds wastes and their extracts

A commercial tannin wine seed extract powder (T), a seed polyphenol extract (Sext) and virgin wine seeds wastes (Se) have been mixed with polypropylene (PP) and tested as long-term stabilizers. Their stabilizing activity has been compared with that of a synthetic antioxidant commonly used within PP (Irganox 1010). Each sample has been subject to both UV and thermal aging. The PP-based films photo-oxidation has been followed through the C=O formation over the aging time by FT-IR. The PP-based tensile specimens have been oven aged and the mechanical properties loss has been investigated monitoring the variation of the elongation at break. Melt Flow Index (MFI) measures and Different Scanning Calorimetry analysis have been conducted on thermally aged samples. At the same time, wine derived additives have been characterized in terms of total polyphenol content, FT-IR and UV/VIS spectra meanwhile catechin and gallic acid have been quantified by LC-MS. Experimental results have evidenced the ability of all the wine derived additives to withstand both to thermal and UV long-term degradation. In particular, wine seeds extracts exhibit the best results in terms of stabilization (even better than Irganox 1010) without compromising the PP mechanical, thermal, morphological and rheological properties

La educación y la cultura urbana: aprender a participar en procesos de mejora urbana. Proyecto educativo: Canillejas imagina un parque.

Presentamos una reflexión sobre el papel de la Educación a partir de las lecciones de la experiencia ' Canillejas imagina un Parque' , un proyecto educativo dirigido por Otro Hábitat en colaboración con el Colegio La Alameda , que busca animar a los alumnos a participar en un proceso de diseño e intervención colectiva para transformar un solar enfrente del colegio. Fa vorecer la participación de los niños en la mejora de su entorno urbano puede ser una estrategia clave para hacer frente a las desigualdades urbanas y generar un entendimiento común sobre la responsabilidad de todos en el desarrollo sostenible de nuestras ciudade

The “New Charter for Health Care Workers” and the ethics of organ donation and transplantation

Comparison is made between the proposals put forward by the “New Charter for Health Care Workers” in the matter of organ transplants and other models of bioethics. The personalist approach adopted by the New Charter is illustrated and the proposals contained in it are finally placed alongside the reference ethical principles underlying the Italian transplant network: they are found to be fully in agreement.

Facial transplantation: from the early trials to ethical and clinical guidelines

Facial transplantation is a complex technique that involves a number of risks. However, although it is not a lifesaving transplant, for individuals in dramatic conditions due to severe facial disfigurements, it constitutes the only possibility of recovering an acceptable quality of life. For this reason, even from an ethical point of view, it is considered an important therapeutic resource, provided it is conducted in rigorously-controlled conditions