26 research outputs found
Materials and processing for power electronics packaging and green technologies
No full textL'abstract è presente nell'allegato / the abstract is in the attachmen
Sustainable Manufacturing of Lightweight Hybrid Nanocomposites for Electric Vehicle Battery Enclosures
No full textNanocomposite laminates containing carbon fibers, epoxy, and multiwalled carbon nanotubes were fabricated using a vacuum bag process. Ecofriendly ionic liquid (5 wt%)-treated multiwalled carbon nanotubes (pristine and nickel-coated) were added to the epoxy independently, in amounts ranging from 1 wt% to 3 wt%, in order to tailor the mechanical, electrical, and thermal performance of manufactured carbon fiber epoxy composite laminates. These nanocomposite laminates were later characterized through flexural testing, dynamic mechanical analysis, impedance spectroscopy, thermal conductivity tests, and FTIR spectroscopy to evaluate their suitability for battery pack applications. The findings showed that both types of multiwalled carbon nanotubes exhibited multifaceted effects on the properties of bulk hybrid carbon fiber epoxy nanocomposite laminates. For instance, the flexural strength of the composites containing 3.0 wt% of ionic liquid-treated pristine multiwalled carbon nanotubes reached 802.8 MPa, the flexural modulus was 88.21 GPa, and the storage modulus was 18.2 GPa, while the loss modulus peaked at 1.76 GPa. The thermal conductivity of the composites ranged from 0.38869 W/(m · K) to 0.69772 W/(m · K), and the electrical resistance decreased significantly with the addition of MWCNTs, reaching a minimum of 29.89 Ω for CFRPIP-1.5 wt%. The structural performance of hybrid nanocomposites containing ionic liquid-treated pristine multiwalled carbon nanotubes was higher than that of the hybrid nanocomposite of ionic liquid-treated Ni-coated multiwalled carbon nanotubes, although the latter was found to possess better functional performance
The role of porosity and acidity in the catalytic upcycling of polyethylene
No full textPlastics have become fundamental and widespread materials in our everyday life. Nowadays, the most demanded plastics are polyolefins, accounting for nearly half of the Global plastic production. However, the end-of-life disposal of these materials is an inevitably issue connected to their increased production. Among chemical recycling techniques, the most thoroughly investigated process is the catalytic pyrolysis, showing a vast panorama of different set-ups optimized for the major production of either gaseous or liquid compounds.
In this contribution a series of mesoporous silica-based materials, either pure SiO2 or substituted with Zr and Al, were systematically synthetized varying both porous framework and surface acidity, in the attempt of rationalizing the effect of each parameter (deeply characterized by physico-chemical methods) on the catalytic pyrolysis of linear low-density polyethylene (LLDPE). The synthetized materials together with some zeolites and aluminas reference samples were tested towards LLDPE degradation in a batch reactor set-up optimized for the formation and accumulation of the gaseous compounds, coupled with IR spectroscopy for in situ monitoring the evolution of the most abundant species (mostly propylene and branched C4-C6 olefins, together with a minor fraction of ethylene and short hydrocarbons). This work points out the necessity of the presence of Brønsted acid sites for a good activity (in terms of both the yield of gaseous products and lowering of the process temperature), but it also reveals a non-negligible role of the Lewis acid sites and it warns about the importance of controlling not only the amount of acid sites but also their strength
Spectrophotometric Detection of Nickel in Water by Lab-on-a-chip Technology: Application to Electroplating
No full textNickel is a metal member of the transition series in the periodic table, and as such shows outstanding properties interesting to the world of industry, namely corrosion resistance to air, water and alkali and electrical conductivity. In fact, nickel is widely employed in electroplating, where high analyte concentrations, up to 100g/L, are required to achieve excellent final results. The process monitoring is required not only to ensure constant and adequate metal-finishing concentration but also to guarantee the safety of wastewater products. To detect nickel, either in high and low metal concentration, a colorimetric method was selected. The spectrophotometric study reveals a well-defined absorption peak at 396nm, giving a calibration curve with remarkable linearity toward metal concentrations, ranging from 1 to 22g/L. By proper optimization process, the detection field can be simply enlarged at least from 100 g/L (100000ppm) to 3*10-3 g/L (3ppm). Due to the presence of an acid part in the electroplating bath, the behaviour of the metal in an acid solution has also been investigated, and the calibration curve still depicts a good linearity of the system.
Achieved results pointed out the suggested colorimetric method as a promising candidate for addressing the requirement for capillary and regular monitoring of nickel in water, throughout a wide range of concentrations.The laboratory method may be readily improved and adapted for microfluidic technology by lowering sample and reagent amounts, miniaturizing sensors, and automating the entire process, from sampling to data recover
Spectrophotometric Detection of Copper in Water by Lab-on-a-chip Technology: Application to Electroplating
No full textAbout the dead: poems
No full textTravis Mossotti writes with humor, gravity, and humility about subjects grounded in a world of grit, where the quiet mortality of working folk is weighed. To Mossotti, the love of a bricklayer for his wife is as complex and simple as life itself: "ask him to put into words what that sinking is, / that shudder in his chest, as he notices / the wrinkles gathering at the corners of her mouth." But not a whiff of sentiment enters these poems, for Mossotti has little patience for ideas of the noble or for sympathetic portraits of hard-used saints. His vision is clear, as clear as the memory of how scarecrows in the rearview, "each of them, stuffed / into a body they didn't choose, resembled / your own plight." His poetry embraces unsanctimonious life with all its wonder, its levity, and clumsiness. About the Dead is an accomplished collection by a writer in control of a wide range of experience, and it speaks to the heart of any reader willing to catch his "drift, and ride it like the billowed / end of some cockamamie parachute all the way / back to the soft, dysfunctional, waiting earth.
Advanced Flow Detection Cell for SPEs for Enhancing In Situ Water Monitoring of Trace Levels of Cadmium
No full textAn advanced anodic stripping voltammetry (ASV)-based Micro Electro Mechanical System (MEMS) sensor for cadmium (Cd) detection is presented in this study, which is cost-effective and efficient for in situ water monitoring, providing a crucial early warning mechanism, streamlining environmental monitoring, and facilitating timely intervention to safeguard public health and environmental safety. The rationale behind this work is to address the critical need for an in situ monitoring system for cadmium (Cd) in freshwater sources, particularly those adjacent to agricultural fields. Cd(II) is a highly toxic heavy metal that poses a significant threat to agricultural ecosystems and human health due to its rapid bioaccumulation in plants and subsequent entry into the food chain. The developed analytic device is composed of a commercial mercury salt-modified graphite screen-printed electrode (SPE) with a custom-designed innovative polydimethylsiloxane (PDMS) flow detection cell. The flow cell was prototyped using 3D printing and replica moulding, with its design and performance validated through COMSOL Multiphysics simulations to optimize inflow conditions and ensure maximum analyte dispersion on the working electrode surface. Chemical detection was performed using square wave voltammetry, demonstrating a linear response for Cd(II) concentrations of 0 to 20 μg/L. The system exhibited robust analytical performance, enabling 25–30 daily analyses with consistent sensitivity within the Limit of Detection (LoD) set by the law of 3 μg/L
Routine Monitoring of Trace Arsenic in Water by Lab-on-a-chip Technology: a Preliminary Study
No full textWater contamination by Arsenic poses a serious risk for human health, due to its manifold toxic effects. The
concern is mainly for drinking water, regarded as the most imperative route of Arsenic exposure to human
beings. The maximum concentration limit for Arsenic in drinking water was fixed by World Health Organisation
(WHO) at 10 μg L−1 but in many developing nations it is increased to 50 μg L−1 due to economic constraints to
detect lower concentrations.
In this scenario, the design of an affordable Arsenic sensor, for routine monitoring of water, is crucial. The
answer to these requirements can be the lab-on–a-chip technology applied to a microfluidic device.
Available detection methods for Arsenic are investigated, focusing on their potential application on a portable
monitoring device: among them a colorimetric method, based on Rodamine B as indicator, and
chronopotentiometry were selected as suitable for the required purpose. Preliminary laboratory tests were aimed
to determine the limit of Arsenic concentration detectable by both the methods; the lower value of 1 μg L−1 was
detected by chronopotentiometry, in good agreement with the required resolution of the measurement.
Moreover, a process optimization adapted the method for the microfluidic technology.
Obtained results point out the new developing lab-on-a-chip technology as good candidate to address the need
for a capillary and frequent monitoring of Arsenic contamination of water by an easy and cheap portable device
Analysis of Quasi-Simultaneous Laser Welding in T-Joint Configuration for PMMA-ABS Using Circular Wobble Geometry
No full textThe focus of this study was the investigation of the quasi-simultaneous laser welding (QSW) technique of polymethyl methacrylate (PMMA) and acrylonitrile butadiene styrene (ABS) in a T-joint configuration using a circular wobble laser path. The main aim was to find how laser parameters, such as scanning speed, number of scans, and laser power, influence key indicators of weld quality: penetration depth and weld strength. A range of scanning speeds (1–2 m/s) and scan repetitions (20–70) was explored, with the goal of keeping the total welding time around 1 s, a time compatible with industrial mass production. The results demonstrated a clear correlation between linear energy density and penetration depth. Deeper penetrations were achieved at higher energy levels. Weld strength was maximized with a lower number of scans (20) and higher powers (above 130 W). The configuration offering the best combination of weld strength (1137 N) and total welding time (0.8 s) was identified, demonstrating the suitability of QSW for mass productio
Exploring circularity in ceramic 3D printing: Possibilities and implementation
No full textNowadays, concepts such as recycling, reusing, and sustainability are gaining ground in a wide range of fields and sectors, including manufacturing. This paradigm shift from “produce-dispose” to “produce-reuse” is pushing manufacturers and producers to move from a linear economy to a circular one. This change in perspective seems more readily applicable to the world of additive manufacturing, as it offers the potential not only to reduce waste generation, but also to reintroduce discarded and recycled materials into the production chain. This implementation of a circular manufacturing approach could be applied to ceramic additive manufacturing. Is it a straightforward process to implement a circular solution into the production chain? Which are the implications for costs, energy requirements, emissions, and waste management? This open discussion aims to identify potential starting points and gaps for further evaluation of future application of circular economy concepts in the ceramic industry
