Search results for " Conductivity"
showing 10 items of 794 documents
Design and Experimental Test of a Thermomagnetic Motor
2012
Abstract This paper presents a Thermomagnetic Motor. The design of the motor is based on a thermal-magnetic coupled dynamic model, which is obtained by assuming the use of a ferromagnetic material working at temperatures near the curie point. The motor is modeled in terms of both its magnetic as well thermal properties (magnetic permeability and thermal conductivity) and the thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is p…
Application of multivariate analysis techniques for selecting soil physical quality indicators: A case study in long-term field experiments in Apulia…
2019
Long-term field experiments and multivariate analysis techniques represent research tools that may improve our knowledge on soil physical quality (SPQ) assessment. These techniques allow us to measure relatively stable soil conditions and to improve soil quality judgment, thereby reducing uncertainties. A monitoring of SPQ under long-term experiments, aimed at comparing crop residue management strategies (burning vs. incorporation of straw, FE1) and soil management (minimum tillage vs. no tillage, FE2), was established during the crop growing season of durum wheat. The relationships between five SPQ indicators (bulk density [BD], macroporosity [PMAC], air capacity [AC], plant available wate…
Ti2Sn3: A Novel Binary Intermetallic Phase, Prepared by Chemical Transport at Intermediate Temperature
2000
Ti2Sn3 was obtained by chemical transport using iodine as the transport agent in a sealed quartz ampule at 500 °C. Its crystal structurea new type structurewas determined via single-crystal structure analysis to be orthorhombic, space group Cmca, a = 595.56(4), b = 1996.4(2), c = 702.81(5) pm, V = 835.6(1) × 106 pm3, and Z = 8. The structure can be derived from a three-dimensional condensation of a single polyhedron, which comprises a Ti atom in the center, surrounded by seven Sn and four Ti atoms forming a tri-capped square antiprism. Supporting the results of the self-consistent band structure calculations, Ti2Sn3 is a metallic p-type conductor, exhibiting Pauli paramagnetism and a specif…
Tripotential data processing for HES interpretation
1994
In this paper some methods are proposed and compared to correct the experimental measurements for preliminary processing of tripotential data which are acquired for HES prospecting. However, the use of those methods should be based upon an accurate analysis of all experimental data. Such an analysis ought to involve: 1) an estimate of the averaged measurement errors with their variance and distribution in both the space and the three apparent-resistivities domains; 2) the choice of a resistivity model capable of describing the actual volume under study. The differences among the three values of apparent resistivity measured on a point are generally influenced both by the resistivity distrib…
N2O and NO emissions by agricultural soils with low hydraulic potentials
2002
N2O and NO production were studied on five agricultural soils with low hydraulic potentials. All experiments were performed in a laboratory under standard incubation conditions to limit any intrinsic soil heterogeneity. The mechanisms involved in NO and N2O production was investigated using the inhibitory properties of acetylene on nitrification and N2O reduction. This work confirmed that N2O and NO could be produced by soils under aerobic conditions. Nitrification seemed to be the only process involved in NO production and the main process involved in N2O production by the five studied soils when the water content was low. Nevertheless, aerobic denitrification with N2O release was observed…
Caractérisation et prédiction du rendement de projection lors du procédé de projection à froid – cas de la métallisation des polymères
2020
This thesis work deals with the cold spray metallization of polymer substrates by aiming at an optimal deposition efficiency using experimental analysis combined with numerical simulation. Experimental observations of the powder jet using an ombroscopic analysis have revealed a generic behavior consisting of a uniform confined zone at the immediate exit of the nozzle followed by a dispersed zone. The supersonic flow at the nozzle exit being essentially axial, the powders are entrained to form a uniform jet. Beyond a certain distance, a dispersion appears. This distance is very important because it characterizes the behavior of the powders. It can alter the conditions for the elaboration of …
Direct determination of oleic acid in soybean oil by capacitively coupled contactless conductivity detection capillary electrophoresis in an oil-misc…
2014
Este trabalho teve por objetivo desenvolver um método analítico direto e rápido para a determinação de ácido oleico em óleo de soja por eletroforese capilar com detecção condutométrica sem contato. O eletrólito de corrida empregado foi uma mistura metanol/1-propanol (1:6 v/v) contendo 4 × 10-2 mol L-1 de KOH e 10% (v/v) em etileno glicol. As amostras foram preparadas pela solubilização de 50 g L-1 de óleo de soja e 1,33 × 10-3 de ácido salicílico (padrão interno) no eletrólito de corrida. Os ensaios quantitativos foram realizados adicionando ácido oleico puro às amostras, na faixa entre 0,53 e 2,13 × 10-3 mol L-1. Sob polaridade negativa, os solutos aniônicos deslocaram-se mais rapidamente …
Hydro-mechanical behaviour of shallow Opalinus Clay shale
2019
In Switzerland, Opalinus Clay shale has been selected as the host formation for radioactive waste disposal. The minimum required depth of the repository is related to the long-lasting isolation required for the disposal (1 million years). During this period, possible erosion scenarios affecting the repository need to be analysed. Opalinus Clay from shallow depths (< 70 m) was sourced from a borehole in Northern Switzerland, where the formation was affected by a considerable exhumation process. This work aims to investigate the impact of the mentioned phenomenon on the hydro-mechanical behaviour of Opalinus Clay through one-dimensional consolidation and permeability measurements. Laboratory …
Defect interaction and local structural distortions in Mg-doped LaGaO3: A combined experimental and theoretical study
2017
A combined experimental and theoretical study of Mg-doped LaGaO3 electrolyte was carried out, with the aim to unveil the interaction between oxygen vacancy (Vo) and perovskite B site cations. LaGaO3 (LG) and LaGa0.875Mg0.125O2.938 (LGM0125) samples were comprehensively characterized by X-ray absorption spectroscopy (XAS) and X-ray diffraction, in order to investigate short- and long-range structures of both undoped and Mg-doped materials. XAS analysis evidenced a preferential Ga-Vo interaction in LGM0125, confirmed by periodic hybrid density functional theory calculations, which were combined with a symmetry-independent classes (SICs) approach in order to (a) obtain a detailed picture of th…
Electric properties of KTiOPO4and NaTiOPO4from temperature-dependent X-ray diffraction
1999
Single crystals of KTiOPO4(KTP) and NaTiOPO4(NaTP) show pronounced pyroelectric behaviour. In order to determine the origin of this property on an atomic scale, X-ray diffraction measurements have been carried out at several temperatures between 100 and 600 K. Modelling of the electron density and the evolution of the structure as a function of temperature has enabled the determination of values for the spontaneous polarization of the compounds and the pyroelectric coefficient of KTP, principally due to the alkaline-ion displacements with a value of 2.0 nC cm−2 K−1. Structure modifications, compared with NaTiOPO4, and the calculation of the electrostatic potential explain the anisotropic be…