922,987 research outputs found
High-performance planar nanoscale dielectric capacitors
We propose a model for planar nanoscale dielectric capacitor consisting of a
single layer, insulating hexagonal boron nitride (BN) stripe placed between two
metallic graphene stripes, all forming commensurately a single atomic plane.
First-principles density functional calculations on these nanoscale capacitors
for different levels of charging and different widths of graphene - BN stripes
mark high gravimetric capacitance values, which are comparable to those of
supercapacitors made from other carbon based materials. Present nanocapacitor
model allows the fabrication of series, parallel and mixed combinations which
offer potential applications in 2D flexible nanoelectronics, energy storage and
heat-pressure sensing systems.Comment: Published version in PR
High Performance Smart Temperature Sensor Using Voltage Controlled Ring Oscillator
In the broadest definition, a sensor is an electronic component, module, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor. Temperature is most-measured process variable in the industrial automation. The most commonly, temperature sensor was used to convert the temperature value to the electrical value. The temperature sensors are the key to read the temperatures correctly and to control the temperature in the industrials applications. Such "smart" temperature sensors combine a sensor and interface electronics on the single chip, and are preferably manufactured in a low-cost standard CMOS process
Supercapatteries as High-Performance Electrochemical Energy Storage Devices
Abstract: The development of novel electrochemical energy storage (EES) technologies to enhance the performance of EES devices in terms of energy capacity, power capability and cycling life is urgently needed. To address this need, supercapatteries are being developed as innovative hybrid EES devices that can combine the merits of rechargeable batteries with the merits of supercapacitors into one device. Based on these developments, this review will present various aspects of supercapatteries ranging from charge storage mechanisms to material selection including electrode and electrolyte materials. In addition, strategies to pair different types of electrode materials will be discussed and proposed, including the bipolar stacking of multiple supercapattery cells internally connected in series to enhance the energy density of stacks by reducing the number of bipolar plates. Furthermore, challenges for this stack design will also be discussed together with recent progress on bipolar plates. Graphic Abstract: Supercapattery is an innovated hybrid electrochemical energy storage (EES) device that combines the merit of rechargeable battery and supercapacitor characteristics into one device. This article reviews supercapatteries from the charge storage mechanisms to the selection of materials including the materials of electrodes and electrolytes. Strategies for pairing different kinds of electrode materials and device engineering are discussed.[Figure not available: see fulltext.
High-performance and low-cost macroporous calcium oxide based materials for thermochemical energy storage in concentrated solar power plants
High energy density, cycling stability, low cost and scalability are the main features required for thermochemical energy storage systems to achieve a feasible integration in Concentrating Solar Power plants (CSP). While no system has been found to fully satisfy all these requirements, the reversible CaO/CaCO3 carbonation reaction (CaL) is one of the most promising since CaO natural precursors are affordable and earth-abundant. However, CaO particles progressively deactivate due to sintering-induced morphological changes during repeated carbonation and calcinations cycles. In this work, we have prepared acicular calcium and magnesium acetate precursors using a simple, cost-effective and easily scalable technique that requires just the natural minerals and acetic acid, thereby avoiding expensive reactants and environmentally unfriendly solvents. Upon thermal decomposition, these precursors yield a stable porous structure comprised of well dispersed MgO nanoparticles coating the CaO/CaCO3 grains that is resistant to pore-plugging and sintering while at the same time exhibits high long term effective conversion. Process simulations show that the employment of these materials could significantly improve the overall CSP-CaL efficiency at the industrial level.Ministerio de EconomĂa y Competitividad CTQ2014-52763-C2, CTQ2017-83602-C
High performance astrophysics computing
The application of high end computing to astrophysical problems, mainly in
the galactic environment, is under development since many years at the Dep. of
Physics of Sapienza Univ. of Roma. The main scientific topic is the physics of
self gravitating systems, whose specific subtopics are: i) celestial mechanics
and interplanetary probe transfers in the solar system; ii) dynamics of
globular clusters and of globular cluster systems in their parent galaxies;
iii) nuclear clusters formation and evolution; iv) massive black hole formation
and evolution; v) young star cluster early evolution. In this poster we
describe the software and hardware computational resources available in our
group and how we are developing both software and hardware to reach the
scientific aims above itemized.Comment: 2 pages paper presented at the Conference "Advances in Computational
Astrophysics: methods, tools and outcomes", to be published in the ASP
Conference Series, 2012, vol. 453, R. Capuzzo-Dolcetta, M. Limongi and A.
Tornambe' ed
High performance structures
Materials selection, structural geometry, proof testing and statistical screening, prestressing, and system energy as tools for designing optimum trusses and other high performance structure
High-Performance Corrosion-Resistant Polymer/Graphene Nanomaterials for Biomedical Relevance
Initially, pristine polymers were used to develop corrosion-resistant coatings. Later, the trend shifted to the use of polymeric nanocomposites in anti-corrosion materials. In this regard, graphene has been identified as an important corrosion-resistant nanomaterial. Consequently, polymer/graphene nanocomposites have been applied for erosion protection applications. Among polymers, conducting polymers (polyaniline, polypyrrole, polythiophene, etc.) and nonconducting polymers (epoxy, poly(methyl methacrylate), etc.) have been used as matrices for anticorrosion
graphene nanocomposites. The corrosion-resistant polymer/graphene nanocomposites have found several important applications in biomedical fields such as biocompatible materials, biodegradable materials, bioimplants, tissue engineering, and drug delivery. The biomedical performance of the nanomaterials depends on the graphene dispersion and interaction with the polymers and living systems. Future research on the anti-corrosion polymer/graphene nanocomposite is desirable to perceive further advanced applications in the biomedical arenas
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