Search results for "Storage"
showing 10 items of 1239 documents
Bottom-Up, On-Surface-Synthesized Armchair Graphene Nanoribbons for Ultra-High-Power Micro-Supercapacitors
2020
Bottom-up-synthesized graphene nanoribbons (GNRs) with excellent electronic properties are promising materials for energy storage systems. Herein, we report bottom-up-synthesized GNR films employed as electrode materials for micro-supercapacitors (MSCs). The micro-device delivers an excellent volumetric capacitance and an ultra-high power density. The electrochemical performance of MSCs could be correlated with the charge carrier mobility within the differently employed GNRs, as determined by pump–probe terahertz spectroscopy studies.
Modelling, Simulation and Characterization of a Supercapacitor in Automotive Applications
2020
The energy storage is one of the most discussed topics among Electrical Vehicles (EVs) research. Currently, supercapacitors (SCs) are collecting even more attention due to their unique features such as high-power density, high life cycle and lack of maintenance. In this paper, a supercapacitor model suitable for the simulation in automotive applications is identified. The model parameters are estimated and used to simulate the behaviour of a commercial SCs bank in different operating conditions. The model is finally validated considering experimental results.
Tunneling spectroscopy of giant vorticity states in superconducting micro- and nanorings at ultra-low temperatures
2008
Abstract When a superconducting contour is exposed to a magnetic field screening currents are induced. At temperatures well below the critical temperature Tc periodicity of the persistent currents can significantly exceed the superconducting flux quantum h / 2 e due to formation of metastable energy states with high quantum winding numbers (vorticity). We have studied the effect in normal metal-insulator-superconductor (NIS) and SIS’IS tunnel structures with the superconducting (S or S′) electrode in a shape of a loop. The tunnel current oscillates due to the modulation of the superconducting density of states by the persistent currents reaching the sub-critical values. In the limit of loop…
Cooling of a superconductor by quasiparticle tunneling
1999
We have extended the cryogenic cooling method based on tunneling between a superconductor and another metal to the case when both metals are superconducting but when their energy gaps are different; earlier, this method was applied between a superconductor and a normal metal. The electron system of a titanium strip with the superconducting transition temperature Tc2=0.51 K has been cooled from 1.02Tc2 to below 0.7Tc2 by this method, using aluminum as the other superconductor.
The quality factor of a superconducting rf resonator in a magnetic field.
2010
The quality factor of a superconducting NbTi resonator at 1.6 MHz in a magnetic field up to 1.2 T as well as its temperature dependence is investigated. A hysteresis effect in the superconducting surface resistance as a function of the magnetic field is observed. An unloaded Q-value of the resonator of 40,500 is achieved at 3.9 K. It is shown that this Q-value is limited by dielectric losses in the FORMVAR insulation of the coils wire. The details of the Q-value optimization are discussed. In the temperature dependence of the Q-value a steep decrease is observed above T approximately = 7.5 K. Finally, the implications of these measurements for real trap experiments are discussed in detail.
Disentangling cardiovascular control mechanisms during head-down tilt via joint transfer entropy and self-entropy decompositions
2015
A full decomposition of the predictive entropy (PE) of the spontaneous variations of the heart period (HP) given systolic arterial pressure (SAP) and respiration (R) is proposed. The PE of HP is decomposed into the joint transfer entropy (JTE) from SAP and R to HP and self-entropy (SE) of HP. The SE is the sum of three terms quantifying the synergistic/redundant contributions of HP and SAP, when taken individually and jointly, to SE and one term conditioned on HP and SAP denoted as the conditional SE (CSE) of HP given SAP and R. The JTE from SAP and R to HP is the sum of two terms attributable to SAP or R plus an extra term describing the redundant/synergistic contribution to the JTE. All q…
Fusing storage and computing for the domain of business intelligence and analytics: research opportunities
2015
With the growing importance of external and shared data, the set of requirements for Business Intelligence and Analytics (BIA) is shifting. Current solutions still come with shortcomings, esp. In multi-stakeholder environments where sensitive content is exchanged. We argue that a new level in the evolution of BIA can be unlocked by tearing down the barriers between storage and computing based on upcoming storage technologies. In particular, we propose a revitalization of ideas from object-oriented databases. We present results from a joint project that aimed at delineating design options for BIA solutions built upon this idea. The paper outlines the interplay of various architectural layers…
Boolean operations with implicit and parametric representation of primitives using R-functions
2005
We present a new and efficient algorithm to accurately polygonize an implicit surface generated by multiple Boolean operations with globally deformed primitives. Our algorithm is special in the sense that it can be applied to objects with both an implicit and a parametric representation, such as superquadrics, supershapes, and Dupin cyclides. The input is a constructive solid geometry tree (CSG tree) that contains the Boolean operations, the parameters of the primitives, and the global deformations. At each node of the CSG tree, the implicit formulations of the subtrees are used to quickly determine the parts to be transmitted to the parent node, while the primitives' parametric definition …
New frontiers in sustainable energy production and storage
2015
Evidently, one of the most effective ways to reduce CO2 emissions consists in the deployment of renewable energies, with the advantage of securing and expanding the energy supplies of a given country. The main problem that arises is due to the intermittent temporary character of many renewable resources like solar and wind. For this reason, it has been recently concluded that in case of high integration of renewables into the distribution grid (more than about 30% of the electricity mix), the implementation of energy storage systems together with smart grids is necessary. Therefore, renewable energies for large scale power production in country would usually require the availability of a su…
Analysis of discrete and continuous distributions of ventilatory time constants from dynamic computed tomography.
2005
In this study, an algorithm was developed to measure the distribution of pulmonary time constants (TCs) from dynamic computed tomography (CT) data sets during a sudden airway pressure step up. Simulations with synthetic data were performed to test the methodology as well as the influence of experimental noise. Furthermore the algorithm was applied to in vivo data. In five pigs sudden changes in airway pressure were imposed during dynamic CT acquisition in healthy lungs and in a saline lavage ARDS model. The fractional gas content in the imaged slice (FGC) was calculated by density measurements for each CT image. Temporal variations of the FGC were analysed assuming a model with a continuous…