1,721,022 research outputs found
Caratterizzazione geotecnica dei materiali marnosi coinvolti negli scivolamenti planari delle Langhe mediante la prova al blu di metilene
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Natural Nanofibers in Polymer Membranes for Energy Applications
No full textNatural fibers from cellulose and chitin are largely used as reinforcing materials thanks to their attracting properties combined with low cost. As a consequence, natural fiber-polymer composites are extremely interesting because they are lightweight, economical and available in a variety of shapes. By modifying either the resin system or the origin or dimensions of the fibers, biocomposites can be designed for different applications. This chapter briefly introduces natural nanofibers and their production processes. It proposes and overviews polymer nanocomposite membranes based on natural fibers, focusing on their application in the energy field, with a discussion of fundamental research in this area
PREPARAZIONE DELLA CARTA DI VULNERABILITÀ PER LA RILOCALIZZAZIONE DI UN IMPIANTO-POZZI DELL'ACQUEDOTTO DI TORINO
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Ultrasensitive Piezoresistive and Piezocapacitive Cellulose-Based Ionic Hydrogels for Wearable Multifunctional Sensing
Full text linkTactile sensors, namely, flexible devices that sense physical stimuli, have received much attention in the last few decades due to their applicability in a wide range of fields like the world of wearables, soft robotics, prosthetics, and e-skin. Nevertheless, achieving a trade-off among stretchability, good sensitivity, easy manufacturability, and multisensing ability is still a challenge. Herein, an extremely flexible strain sensor composed of a cellulose-based hydrogel is presented. A natural biocompatible carboxymethylcellulose (CMC) hydrogel endowed with ionic conductivity by sodium chloride (NaCl) was used as the sensitive part. Both the sensible layer and electrodes were investigated with an innovative approach for wearable sensor applications based on electrochemical impedance spectroscopy to find the best device configuration. The sensor, exploitable both as a piezoresistor and as a piezocapacitor, presents high sensitivity to external stimuli, together with an extreme stretchability of up to 600%, showing the best strain and temperature sensitivity among the ionic conductive hydrogel-based devices presented in the literature. The very high strain sensitivity enables the hydrogel to be implemented in wearable strain sensors to monitor different human motions and physiological signals, representing a valid solution for the realization of transparent, easily manufacturable, and low-environmental-impact devices
Current and emerging trends in polymeric 3D printed microfluidic devices
Full text linkDuring the last two decades, 3D printing technology has emerged as a valid alternative for producing microfluidic devices. 3D printing introduces new strategies to obtain high precision microfluidic parts without complex tooling and equipment, making the production of microfluidic devices cheaper, faster, and easier than conventional fabrication methods such as soft lithography. Among the main 3D techniques used for this purpose, fused filament manufacturing (FFF), inkjet 3D printing (i3Dp) and vat polymerization (VP) are of the greatest interest since they are well-established techniques in the field and are cost-affordable both in equipment and material. However, there are still some barriers in terms of technology and materials to overtake for definitively establishing 3D printing as a truly microfluidic production method. For example, the level of resolution and precision of 3D printed microfluidic parts still does not reach the level of conventional fabrication techniques, and, from a materialistic point of view, few materials present the desired characteristics (e.g., biocompatibility, optical transparency, and mechanical properties) for target areas such as medicine, analytical chemistry, and pharmaceuticals. This review intends to evaluate and analyze the current state of polymeric 3D printing techniques and materials to manufacture microfluidic chips. The article will show and discuss the latest innovations, materials, and applications of such 3D printed microstructures. The focus of this review is to provide an overview of recent and future developments in 3D printing and materials in the branch of microfluidics fabrications, showing that the selection of the right materials together with the design freedom afforded by 3D printing will be the cornerstone for microfluidic development
Photocrosslinked Chitosan Hydrogels Reinforced with Chitosan-Derived Nano-Graphene Oxide
Full text linkChitosan and chitosan-derived nano-graphene oxide carbon dots are successfully methacrylated and utilized for the fabrication of photocurable hydrogels. The addition of the nano-graphene oxide (nGO) does not significantly delay the polymer network build-up, but significantly reduces the storage modulus of the crosslinked network, with important detrimental effects on the mechanical performance. By replacing nGO with methacrylated M-nGO, the mechanical performance of the crosslinked polymer network is improved with an increase of the storage modulus as a function of increasing the M-nGO content in the photocurable formulation
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