211 research outputs found
Low Energy, Coherent, Stoner-like Excitations in CaFeAs
Using linear-response density-functional theory, magnetic excitations in the
striped phase of CaFeAs are studied as a function of local moment
amplitude. We find a new kind of excitation: sharp resonances of Stoner-like
(itinerant) excitations at energies comparable to the N{\'{e}}el temperature,
originating largely from a narrow band of Fe states near the Fermi level,
and coexist with more conventional (localized) spin waves. Both kinds of
excitations can show multiple branches, highlighting the inadequacy of a
description based on a localized spin model
COMMUNICATING WITH AN ENERGY METER USING IEC 62056 THROUGH TCP/IP PROTOCOL
Device Language Message Specification (DLMS) is an application layer protocol designed to support messaging to and from energy distribution devices in a computer integrated environment. COSEM, the Companion Specification for Energy Metering, addresses the meter as an integrated part of a commercial process, which starts with the measurement of the delivered product (energy) and ends with the revenue collection. The DLMS/COSEM specification specifies a data model and communication protocols for data exchange with metering equipment. Communication with electricity metering equipment using the COSEM interface classes is based on the client – server paradigm, where the Meter plays the role of server and the client is a Meter Reading Instrument. Different types of communication media are used to retrieve parameters from energy meter. This paper aims to establish a communication with energy meter by using DLMS/COSEM and access meter data with TCP/IP based communication media
Ultra-fast self-assembly and stabilization of reactive nanoparticles in reduced graphene oxide films.
Nanoparticles hosted in conductive matrices are ubiquitous in electrochemical energy storage, catalysis and energetic devices. However, agglomeration and surface oxidation remain as two major challenges towards their ultimate utility, especially for highly reactive materials. Here we report uniformly distributed nanoparticles with diameters around 10 nm can be self-assembled within a reduced graphene oxide matrix in 10 ms. Microsized particles in reduced graphene oxide are Joule heated to high temperature (∼1,700 K) and rapidly quenched to preserve the resultant nano-architecture. A possible formation mechanism is that microsized particles melt under high temperature, are separated by defects in reduced graphene oxide and self-assemble into nanoparticles on cooling. The ultra-fast manufacturing approach can be applied to a wide range of materials, including aluminium, silicon, tin and so on. One unique application of this technique is the stabilization of aluminium nanoparticles in reduced graphene oxide film, which we demonstrate to have excellent performance as a switchable energetic material
Compositional disorder and its influence on the structural, electronic and magnetic properties of MgC(Ni_{1-x}Co_{x})_{3} alloys using first-principles
First-principles, density-functional based electronic structure calculations
are carried out for MgC(Ni_{1-x}Co_{x})_{3} alloys over the concentration range
0\leq x\leq1, using Korringa-Kohn-Rostoker coherent-potential approximation
(KKR CPA) method in the atomic sphere approximation (ASA). The self-consistent
calculations are used to study the changes as a function of x in the equation
of state parameters, total and partial densities of states, magnetic moment and
the on-site exchange interaction parameter. To study the magnetic properties as
well as its volume dependence, fixed-spin moment calculations in conjunction
with the phenomenological Landau theory are employed. The salient features that
emerge from these calculations are (i) a concentration independent variation in
the lattice parameter and bulk modulus at x~0.75 with an anomaly in the
variation of the pressure derivative of bulk modulus, (ii) the fixed-spin
moment based corrections to the overestimated magnetic ground state for 0.0\leq
x\leq0.3 alloys, making the results consistent with the experiments, and (iii)
the possibility of multiple magnetic states at x~0.75, which, however, requires
further improvements in the calculations
Analogies between optical propagation and heat diffusion: applications to microcavities, gratings and cloaks
International audienceA new analogy between optical propagation and heat diffusion in heterogeneous anisotropic media has beenproposed recently [S. Guenneau, C. Amra, and D. Veynante, Optics Express Vol. 20, 8207-8218 (2012)]. A detailedderivation of this unconventional correspondence is presented and developed. In time harmonic regime, all thermalparameters are related to optical ones in artificial metallic media, thus making possible to use numerical codesdeveloped for optics. Then the optical admittance formalism is extended to heat conduction in multilayeredstructures. The concepts of planar micro-cavities, diffraction gratings, and planar transformation optics for heatconduction are addressed. Results and limitations of the analogy are emphasized
Constraints perceived by the field extension functionaries of Dairy Development Department, Kerala
The study was conducted in Kerala state in 2021–2022, with the objective of identifying the constraints related to effective role performance as perceived by the Field Extension Functionaries (FEFs) of the Dairy Development Department (DDD). Through non-proportionate stratified random sampling, a sample of 120 FEFs was chosen, of whom 60 were Dairy Extension Officers (DEOs) and 60 were Dairy Farm Instructors (DFIs). The study found that inadequate infrastructure facilities and lack of transport facilities were the major physical constraints perceived by the respondents. Among organisational constraints, inadequate staff strength and heavy administrative work were cited as the major constraints. The most significant technological constraints perceived were inadequate knowledge about dairy innovations among the farmers and lack of technical support for implementing schemes. Inadequate budget allocation for programme execution and lack of monitoring and evaluation of schemes were the major managerial constraints. Under communication constraints, weak research-extension-farmer linkage, and lack of feedback from farmers were perceived as the major ones
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