Sulfonation of PEEK-WC polymer via chloro-sulfonic acid for potential PEM fuel cell applications

The preparation and characterization of thin dense sulfonated poly-ether-ether-ketone with cardo group (PEEK-WC) membranes for proton exchange membrane fuel cell (PEMFC) applications are described. The sulfonation of PEEK-WC polymer was realized via chloro-sulfonic acid and different kinds of membrane samples were prepared with a sulfonation degree ranging from 67 to 99%. The degree of sulfonation, homogeneity and thickness significantly affect both the membrane transport properties and the electrochemical performances. The dense character of the membranes was confirmed by SEM analysis. Proton conductivity measurements were carried out in a temperature range from 30 to 80 °C and at 100% of relative humidity, reaching 5.40×10⁻³ S/cm⁻¹ as best value at 80 °C and with a sulfonation degree (DS) of 99%. At the same conditions, a water uptake of 17% was achieved. DSC and TGA characterizations were used in order to determine the thermal stability of the membranes, confirming a T_g ranging between 206 and 216 °C depending on the DS, whereas FT-IR yielded indication about intermolecular interactions and water uptake at various sulfonation degrees.     

Uncertainty Estimation in Simultaneous Measurements of Levels and Permittivities of Liquids Using TDR Technique

Time-domain reflectometry (TDR) based on instruments are commonly used for several monitoring methods, particularly in soil moisture and volumetric water-content evaluation. Furthermore, significant advantages of TDR methodology, mostly related to the possible determination in real-time and to a nondestructive approach of the spatial location and nature of various objects, make this technique an appealing candidate for a variety of environmental and industrial applications. In this paper, we show that the suitable combination of TDR-detecting functionalities can lead to a joint quantitative and qualitative monitoring method for liquid-control purposes, so that, in one shot, the analysis of TDR data allow the measurement of liquid levels, the determination of multiple interfaces in layered media, as well as the evaluation of dielectric properties, thus opening challenging perspectives for several monitoring applications, particularly in fluid-processing-related industry. For such purposes, a detailed analysis of the uncertainty of the proposed measurement method is mandatory; hence, a metrological characterization of the method is carried out, demonstrating that the presented technique is definitely valid for simultaneously measuring levels and dielectric constants of liquids, with uncertainties under 2%. Results obtained for different liquid samples validate the approach on a wide range of dielectric materials and demonstrate the robustness and reliability of the proposed TDR technique.     

Hydrogen Incorporation in III‐N‐V Semiconductors: From Macroscopic to Nanometer Control of the Materials’ Physical Properties

The effects of hydrogen incorporation in dilute nitride semiconductors, specifically GaAs_1‐xN_x, are discussed. The remarkable consequences of hydrogen irradiation include tuneable and reversible changes in the electronic, optical, structural, and electrical properties of these materials. The highly trapping‐limited diffusion of H atoms in dilute nitrides results in the formation of extremely sharp heterointerfaces between H‐containing and H‐free regions of the crystals. This, in turn, offers an unprecedented possibility to tailor the physical properties of a semiconductor chip in its growth plane with nanometer precision. A number of examples are presented and discussed.     

Galectin 1—A Key Player between Tissue Repair and Fibrosis

Galectins are ten family members of carbohydrate-binding proteins with a high affinity for β galactose-containing oligosaccharides. Galectin-1 (Gal-1) is the first protein discovered in the family, expressed in many sites under normal and pathological conditions. In the first part of the review article, we described recent advances in the Gal-1 modulatory role on wound healing, by focusing on the different phases triggered by Gal-1, such as inflammation, proliferation, tissue repair and re-epithelialization. On the contrary, Gal-1 persistent over-expression enhances angiogenesis and extracellular matrix (ECM) production via PI3K/Akt pathway activation and leads to keloid tissue. Therefore, the targeted Gal-1 modulation should be considered a method of choice to treat wound healing and avoid keloid formation. In the second part of the review article, we discuss studies clarifying the role of Gal-1 in the pathogenesis of proliferative diabetic retinopathy, liver, renal, pancreatic and pulmonary fibrosis. This evidence suggests that Gal-1 may become a biomarker for the diagnosis and prognosis of tissue fibrosis and a promising molecular target for the development of new and original therapeutic tools to treat fibrosis in different chronic diseases.     

Assessing drivers of energy consumption and progress toward energy targets in Italy

ABSTRACT

The objectives of this study are to provide new insights on (i) the drivers of changes in final energy consumption in Italy over the period from 1995 to 2015 by employing a multi-sectoral decomposition analysis approach – Logarithmic Mean Divisia Index I (LMDI-I); and (ii) the progress of Italy toward the indicative energy efficiency and mandatory energy-saving targets set for 2020. The decomposition results show that from 1995 to 2015, an increase in final energy consumption caused by activity effects has been almost totally offset by structural changes. Energy intensity improvements occurred during the period from 2006 to 2015 when most of the energy efficiency policies in Italy were implemented. However, unlike the ex ante estimates of energy savings reported by the Italian government, the LMDI-I analysis shows that Italy is not on track to achieve the 2020 energy efficiency and energy-saving targets. Challenges and opportunities in policymaking are discussed.     

On the application of generalized integral transform technique to wind‐induced vibrations on overhead conductors

The aim of the present paper is to describe the application of the generalized integral transform technique (GITT) for the theoretical analysis of wind‐induced vibrations on overhead conductors. In the mathematical model adopted, the complicated helicoidal geometry of the conductor is simplified by treating it as a homogeneous taut string simple supported at both ends. Solving the governing partial differential equation through the GITT approach, one derives purely analytical or analytical–numerical solutions for the conductor transverse displacement as a function of both position and time. In order to highlight the potential and flexibility of the GITT approach to account for realistic features of the phenomenon, three particular cases of practical interest are analyzed in detail, for which benchmark results are provided: (i) the damped‐free vibrations of the conductor; (ii) the harmonic‐forced vibrations of the conductor without and with Stockbridge dampers; and (iii) the forced vibrations of the conductor under a non‐linear wind excitation. The current results may be combined with previous analytical predictions to compute the conductor amplitudes and bending strains at critical locations. Although this work is focused on a taut string model for the conductor, the approach described herein may be easily extendable to the beam model. Copyright © 2008 John Wiley & Sons, Ltd.     

A TDR Method for Real-Time Monitoring of Liquids

Time-domain-reflectometry (TDR) measurements, which were originally used to locate and diagnose faults in transmission lines, have been widely applied in geology and soil science for accurate and flexible measurements of soil moisture and water content. Furthermore, the most attractive advantages of TDR rely on the possible determination of the spatial location and nature of various objects, both in real time and with a nondestructive approach. This makes the TDR technique an appealing candidate for a variety of environmental and industrial applications. Although the TDR instruments are commonly used to date, particularly for the aforementioned purposes, the state of the art is rather lacking in liquid-monitoring applications. This paper describes how the suitable combination of TDR detecting functionalities can lead to a simultaneous monitoring of quantitative and qualitative properties of liquid samples. In fact, the proposed TDR method allows, in one shot, the measurement of liquid levels, the determination of multiple interfaces in layered media, and the evaluation of dielectric properties such as dielectric permittivity or electrical conductivity. Some applications to real cases are proposed, which are referred to petrol-chemical mixtures or water-based liquids, thus validating the approach on a wide range of materials.     

A virtual reality approach for usability assessment: case study on a wheelchair-mounted robot manipulator

The aim of the paper is to address an innovative methodology for assessing the usability of a product. This methodology is particularly suitable for designing products that provide their main functions through their control interfaces. In particular, this case study relates to the usability assessment of two control devices for a wheelchair-mounted robot manipulator to assist physically disabled people. The study focuses on defining a synthetic usability index on the basis of two currently used methods: the multi criteria decision analysis and the Saaty’s analytic hierarchy process. Several virtual reality (VR)-based experiments have been conducted, set up in accordance with a cross-array experimental plan, that adequately caters for both control and noise factors. Quantitative measures and subjective user evaluations have been collected to maximize the effectiveness, the efficiency and the satisfaction perceived by users while using the product. Compared to the literature on the subject, the proposed approach provides both more flexibility in defining quantitative indexes and more adequate results, even when involving only a small sample of users in the participatory design session. The use of VR technologies for the collection of the experimental data has been essential in terms of safety, costs and repeatability of the tests, as well as of the robustness with respect to noise factors.