1,721,458 research outputs found
On master test plans for the space of BV functions
No full textNobili F, Pasqualetto E, Schultz T. On master test plans for the space of BV functions. Advances in Calculus of Variations . 2022.We prove that on an arbitrary metric measure space a countable collection of test plans is sufficient to recover all BV functions and their total variation measures. In the setting of non-branching CD(K, N) spaces (with finite reference measure), we can additionally require these test plans to be concentrated on geodesics
A first-order condition for the independence on p of weak gradients
Full text linkIt is well known that on arbitrary metric measure spaces, the notion of minimal p-weak upper gradient may depend on p. In this paper we investigate how a first-order condition of the metric-measure structure, that we call Bounded Interpolation Property, guarantees that in fact such dependence is not present. We also show that the Bounded Interpolation Property is stable for pointed measure Gromov Hausdorff convergence and holds on a large class of spaces satisfying curvature dimension conditions
Methods and Instruments | Transmission Electron Microscopy
No full textTransmission Electron Microscope (TEM) and related techniques, such as High-Resolution Transmission Electron Microscopy (HRTEM), Scanning Transmission Electron Microscopy (STEM), principles and applications in the field of electrochemical power sources are briefly described. Instrumentation and operation are introduced together with the basis of electron scattering phenomena that generate contrast both in the real (imaging mode) and reciprocal space (diffraction mode). Applications of TEM to the study of materials in electrochemical devices are discussed demonstrating the capability of this technique in the characterization of electrochemically active materials down to the atomic scale, also by the mean of innovative methods such as operando- and cryo-STEM
Methods and Instruments | Scanning Electronic Microscopy
No full textScanning Electron Microscopy (SEM) principles are introduced and some applications to the characterization of electrochemical power sources are presented. The general features of a SEM microscope are briefly described with particular attention to: (i) generation and focusing of the electron beam over the samples; (ii) interactions between electrons and atoms in the sample producing the analytical signals; (iii) detection and recording of secondary or backscattered electrons for image reconstruction; (iv) detector of X-rays and electron probe microanalysis. Some applications of the technique in the field of electrochemical storage devices are summarized, with the aim of shedding light onto the relationships between morphology/composition and electrochemical behavior of electrodes. Finally, an outlook on recent methodologies is given,
such as environmental SEM which, operating under moderate pressures, allows in situ monitoring of chemical and morphological transformations related to electrochemical power sources
Fast file transfers from IoT devices by using multiple interfaces
No full textThe Internet-of-Things (IoT) is a modern technological revolution that enables communication amongst a plethora of different devices. To date, about 30 billion devices have been connected to the internet and more than 75 billion devices are probably to be connected worldwide by 2025. These can range from small sensors and actuators to larger devices such as smartphones, drones or even buildings and interconnected cars. Devices are often mobile and battery powered thus their communication requires fast and energy efficient solutions. To this end, this paper studies the use of multi-interface communication for fast and energy efficient communication. In particular, we consider the basic operation of data transfer between smartphones in the form of files. This task can be performed for backup purposes, and hence it represents a useful and frequent operation that users perform. Our aim is to provide a new and easy means that optimises file transfers with respect to time and energy consumption. In particular, as smartphones are endowed with various connecting interfaces like Bluetooth, WiFi and 4G, we conduct experimental studies by varying different parameters in order to understand the best setting, including which interface is more appropriate to accomplish file transfer. To this respect, we also implemented an innovative and light app that allows the use of two or more interfaces concurrently. The experimental results show how the coupling of some interfaces might be effective in terms of time, while consuming a negligible amount of energy. Actually, such results become more and more interesting as the size of the file to be transferred grows. The best combination experienced is by making use of WiFi at 5 GHz concurrently with 4G, whereas WiFi at 2.4 GHz caused interference complications
La compagine della coscienza e la struttura intenzionale. Commento alla Quinta ricerca logica (§§ 1-21)
No full textThe Fifth Logical Investigation performs a frame-function in the economy of the Logical Investigations For it is here that the reader can perceive the overall intent of the work, and the studies of the first four researches fully reveal their urgency as parts of a puzzle that is reassembled in the fifth. Here Husserl makes clear his intent to provide an overall analysis of consciousness and its functioning in the elaboration of meanings. The article analyzes the central passages of the text against the backdrop of the debate of the late 19th and early 20th centuries
A first-order condition for the independence on of weak gradients
No full textIt is well known that on arbitrary metric measure spaces, the notion of
minimal -weak upper gradient may depend on .
In this paper we investigate how a first-order condition of the
metric-measure structure, that we call Bounded Interpolation Property,
guarantees that in fact such dependence is not present.
We also show that the Bounded Interpolation Property is stable for pointed
measure Gromov Hausdorff convergence and holds on a large class of spaces
satisfying curvature dimension conditions.Comment: Revised version, to appear in J. Funct. Ana
Rigidity and almost rigidity of Sobolev inequalities on compact spaces with lower Ricci curvature bounds
No full textWe prove that if M is a closed n-dimensional Riemannian manifold, n \ge 3, with \mathrm{Ric}\ge n-1 and for which the optimal constant in the critical Sobolev inequality equals the one of the n-dimensional sphere \mathbb {S}^n, then M is isometric to \mathbb {S}^n. An almost-rigidity result is also established, saying that if equality is almost achieved, then M is close in the measure Gromov–Hausdorff sense to a spherical suspension. These statements are obtained in the \mathrm {RCD}-setting of (possibly non-smooth) metric measure spaces satisfying synthetic lower Ricci curvature bounds. An independent result of our analysis is the characterization of the best constant in the Sobolev inequality on any compact \mathrm {CD} space, extending to the non-smooth setting a classical result by Aubin. Our arguments are based on a new concentration compactness result for mGH-converging sequences of \mathrm {RCD} spaces and on a Pólya–Szegő inequality of Euclidean-type in \mathrm {CD} spaces. As an application of the technical tools developed we prove both an existence result for the Yamabe equation and the continuity of the generalized Yamabe constant under measure Gromov–Hausdorff convergence, in the \mathrm {RCD}-setting.peerReviewe
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