Istituto Nazionale di Ricerca Metrologica
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Bioresorbable phosphate glass microstructured optical fibers with hole and core for biomedicine
Get PDFOver the last decades, there has been a growing interest towards optical fiber technology for biomedical field. Several applications that require insertion of optical fibers into the human body will take advantage of the availability of bioresorbable fibers able to be gradually resorbed by the tissue eliminating the need for follow-up explant surgery. Calcium-phosphate glasses have been designed and synthesized in our laboratory to be dissolvable in biological fluids while showing a wide range of transparency, mechanical reliability, and suitability for both preform extrusion and fiber drawing. Step index single-mode and multi-mode optical fibers have been drawn from these glasses using a custom-made induction heated drawing tower. In this work we report the fabrication of a microstructured bioresorbable optical fiber featuring a multi-mode core and a microfluidic channel. The preform was drawn to 130 and 230 μm diameter fibers. Light guide and attenuation loss were characterized, and the microfluidic channel was tested for liquid delivery. The proposed fiber shows a vast potentiality in theragnostic applications where the ability of delivery liquid and light simultaneously could enable novel devices to be employed in specific areas inside the body without needing a removal procedure
3D printed lattice metal structures for enhanced heat transfer in latent heat storage systems
Get PDFThe low thermal conductivity of Phase Change Materials (PCMs), e.g., paraffin waxes, is one of the main drawbacks of latent heat storage, especially when fast charging and discharging cycles are required. The introduction of highly conductive fillers in the PCM matrix may be an effective solution; however, it is difficult to grant their stable and homogeneous dispersion, which therefore limits the resulting enhancement of the overall thermal conductivity. Metal 3D printing or additive manufacturing, instead, allows to manufacture complex geometries with precise patterns, therefore allowing the design of optimal paths for heat conduction within the PCM. In this work, a device-scale latent heat storage system operating at medium temperatures (similar to 90 celcius) was manufactured and characterized. Its innovative design relies on a 3D Cartesian metal lattice, fabricated via laser powder bed fusion, to achieve higher specific power densities. Numerical and experimental tests demonstrated remarkable specific power (approximately 714 +/- 17 W kg-1 and 1310 +/- 48 W kg-1 during heat charge and discharge, respectively). Moreover, the device performance remained stable over multiple charging and discharging cycles. Finally, simulation results were used to infer general design guidelines to further enhance the device performance. This work aims at promoting the use of metal additive manufacturing to design efficient and responsive thermal energy storage units for medium-sized applications, such as in the automotive sector (e.g. speed up of the engine warm up or as an auxiliary for other enhanced thermal management strategies)
Developing Quantitative Nondestructive Characterization of Nanomaterials: A Case Study on Sequential Infiltration Synthesis of Block Copolymers
Get PDFThe sequential infiltration synthesis (SIS) of inorganic materials in nanostructured block copolymer templates has rapidly progressed in the last few years to develop functional nanomaterials with controllable properties. To assist this rapid evolution, expanding the capabilities of nondestructive methods for quantitative characterization of the materials properties is required. In this paper, we characterize the SIS process on three model polymers with different infiltration profiles through ex situ quantification by reference-free grazing incidence X-ray fluores-cence. More qualitative depth distribution results were validated by means of X-ray photoelectron spectroscopy and scanning trans-mission electron microscopy combined with energy-dispersive X-ray spectroscopy
Determination of uncertainty of coordinate measurements on the basis of the formula for EL,MPE
Get PDFaccording to ISO/TS 15530-1, developed at University of Bielsko-Biała, is presented. Measurement uncertainty is
estimated on the basis of information contained in the formula for the maximum permissible error (EL,MPE) of the
applied coordinate measuring system (CMS) and on the basis of its acceptance or reverification test results.
Measurement models are of the nature of close mathematical dependencies expressing the measured characteristic
in the form of a distance which is a function of coordinates differences of a low number of essential points,
properly selected on the workpiece. Measurement models for dimensions and various geometrical deviations
were developed. Thanks to the applied vector notation the models are in the form of cross and dot products and
they are easily programmable in software such as Matlab, Maple or Python. Detailed examples of the uncertainty
analysis for two characteristics (position deviations of the axes of the holes in relation to the datum system) of a
car steering knuckle are provided
Performance study of a thin film cation exchange membrane on carbon electrode for supercapacitor application
Get PDFIn this work we report a green procedure for the infiltration of a SPEEK solution into a porous carbon electrode resulting in a thin-film cation exchange membrane. The electrodes have been investigated by a morphological point of view, showing the formation of a thin coating infiltrated into the porous carbonaceous matrix, while mechanical peeling of a tape demonstrated the adhesion of the proposed layer. The fabricated electrodes have been analyzed by electrochemical measurement. The 3-electrode cyclic voltammetry measurements allowed to verify the voltage window resulting in an improved negative potential, while the electrochemical impedance spectroscopy showed a reduction of the electrical resistance. The SPEEK electrode was used in a supercapacitor and deeply characterized by electrochemical analysis. The reported findings demonstrate for the first time the possibility to exploit a cation exchange material in thin film configuration for supercapacitor application with improved performance of the device and exclusively involving the use of nontoxic reagents
Optimization of Laser-Induced Graphene Electrodes for High Voltage and Highly Stable Microsupercapacitors
Get PDFMicrosupercapacitors (μSCs) have received a lot of interest for their possible use in miniaturized electronics and in the field of the Internet of Things (IoT) to power distributed sensors. μSCs fill the gap between batteries and traditional capacitors, providing high power densities and acceptable energy densities to fulfill onboard power supply requirements, coupled with quick charge/discharge rates and extended lifetime. Charge balancing of μSCs is not a standard practice, although the optimization of electrodes can provide beneficial effects on the electrochemical performance and stability of the device. In this work, a charge-balanced double-layer μSC based on laser-induced graphene (LIG) with [PYR14][TFSI] as an ionic liquid electrolyte is presented for the first time. The optimized device shows an improvement in terms of the increased lifetime of a factor of four and its energy efficiency is raised above 80%
PFAS: A Review of the State of the Art, from Legislation to Analytical Approaches and Toxicological Aspects for Assessing Contamination in Food and Environment and Related Risks
Get PDFMore than 7000 synthetic compounds known as per- and poly-fluoroalkyl substances (PFAS) are applied to food packaging and other materials to provide fat, fire, and/or water resistance properties. These compounds have exceptional environmental stability and persistence due to the strong C-F chemical bond, earning them the moniker “forever chemicals”. Emission of PFAS from industrial waste leads to water, air, and soil contamination. Due to this ubiquitous nature, combined with the fact that PFAS in humans are known to have carcinogenic and reprotoxic effects and to cause vaccine resistance and depression of the immunity system, PFAS may constitute a major threat to human health. For this reason, the attention of the scientific community and of control bodies is increasing and as a consequence legislation and the scientific literature on PFAS are constantly evolving. This review aims to provide a comprehensive overview of the state of the art about current legislation addressing PFAS; targeted and screening method for identification, detection and quantification of PFAS; toxicity of PFAS; and contamination of environmental and food matrices and from food contact matrices. A comprehensive review of the latest scientific research and recent developments in the legislation of PFAS will provide insights into the current understanding of PFAS and its health implications. Moreover, it will serve as a valuable reference for further studies related to PFAS and could help in informing future policy decisions
Multifunctional effects in magnetic nanoparticles for precision medicine: combining magnetic particle thermometry and hyperthermia
Get PDFAn effective combination of magnetic hyperthermia and thermometry is shown to be implementable by using magnetic nanoparticles which behave either as a heat sources or as temperature sensors when excited at two different frequencies. Noninteracting magnetite nanoparticles are modeled as double-well systems and their magnetization is obtained by solving rate equations. Two temperature sensitive properties derived from the cyclic magnetization and exhibiting a linear dependence on temperature are studied and compared for monodisperse and polydisperse nanoparticles. The multifunctional effects enabling the combination of magnetic hyperthermia and thermometry are shown to depend on the interplay among nanoparticle size, intrinsic magnetic properties and driving-field frequency. Magnetic hyperthermia and thermometry can be effectively combined by properly tailoring the magnetic properties of nanoparticles and the driving-field frequencies