Search results for "Temperature gradient"
showing 10 items of 73 documents
Constraints on the Cretaceous thermal event in the Transantarctic Mountains from alteration processes in Ferrar flood basalts
1999
Abstract K–Ar and 40 Ar/ 39 Ar incremental-heating analyses on apophyllite formed during hydrothermal alteration of volcanic rocks from the Ferrar Supergroup in North Victoria Land, Antarctica, provide strong evidence for hydrothermal events during mid-Cretaceous time. A last event has been dated at 96.7±0.6 Ma. Variable older ages between 112 and 125 Ma are interpreted as mixed ages of hydrothermal events or may be caused by disturbances of the Ar–Ar system. The Rb–Sr isotope system of the apophyllites is not applicable to dating because a large portion of the Sr is radiogenic and because of Rb-mobility in the crystal structure. Secondary mineralogy suggests a temperature for alteration be…
Microbiological investigation of Raphanus sativus L. grown hydroponically in nutrient solutions contaminated with spoilage and pathogenic bacteria
2012
Abstract The survival of eight undesired (spoilage/pathogenic) food related bacteria (Citrobacter freundii PSS60, Enterobacter spp. PSS11, Escherichia coli PSS2, Klebsiella oxytoca PSS82, Serratia grimesii PSS72, Pseudomonas putida PSS21, Stenotrophomonas maltophilia PSS52 and Listeria monocytogenes ATCC 19114T) was investigated in mineral nutrient solution (MNS) during the crop cycle of radishes (Raphanus sativus L.) cultivated in hydroponics in a greenhouse. MNSs were microbiologically analyzed weekly by plate count. The evolution of the pure cultures was also evaluated in sterile MNS in test tubes. The inoculated trials contained an initial total mesophilic count (TMC) ranging between 6.…
Polymorphism of mytilin B mRNA is not traslated into mature peptide
2008
Diversity of mRNAs from mytilin B, one of the five mytilins identified in the Mediterranean mussel, Mytilus galloprovincialis, has been investigated from circulating hemocytes. One mussel expressed simultaneously two to ten different mytilin B mRNAs as observed in denaturing gradient gel electrophoresis (DGGE), defining 10 individual DGGE patterns (named A to J) within the mussels from Messina, Sicily (Italy). Three patterns accounted for 79% of the individuals whereas other patterns were found in only 2-7% of the 57 analyzed mussels. Base mutations were observed at specific locations, mainly within COOH-terminus and 3'UTR, leading to 36 nucleotide sequence variants and 21 different coding …
Thermoelectric effects on electrically conducting particles in liquid metal
2015
International audience; The present paper deals with the thermoelectric effect on a solid electrically conducting particle immersed in a liquid metal under a temperature gradient. Superimposition of a static magnetic field induces thermoelectric magnetic (TEM) forces both in the solid and in the liquid. Considering a simple spherical particle, the electric current density and the corresponding forces can be calculated analytically. Two cases are considered according to the orientation of the magnetic field with respect to the temperature gradient. The corresponding flow fields around the particle are calculated in both cases. Grain motion is analyzed in the light of in-situ experiments perf…
Non-isothermal separation of ferrofluid particles through grids: Abnormal magnetic Soret effect
2013
Abstract Nanoparticle transport through thin non-isothermal ferrofluid layer between permeable walls is investigated. The transient mass flux is determined from measurements of particle concentration changes in two fluid chambers of different temperatures which are attached on both sides of the layer. Experiments are performed employing fluid samples of small ordinary magnetic Soret effect, which is detected by thermal grating technique. The separation measurements say that a magnetic field, aligned along a temperature gradient, causes a remarkable increase in the mass diffusion coefficient and a simultaneous decrease in particle thermodiffusion mobility. It is proposed that the observed ef…
Influence of thickness and interface on the low-temperature enhancement of the spin Seebeck effect in YIG films
2016
The temperature-dependent longitudinal spin Seebeck effect (LSSE) in heavy metal (HM)/Y_{3}Fe_{5}O_{12} (YIG) hybrid structures is investigated as a function of YIG film thickness, magnetic field strength, and different HM detection materials. The LSSE signal shows a large enhancement with reductions in temperature, leading to a pronounced peak at low temperatures. We find that the LSSE peak temperature strongly depends on the film thickness as well as on the magnetic field. Our result can be well explained in the framework of magnon-driven LSSE by taking into account the temperature-dependent effective propagation length of thermally excited magnons in the bulk of the material. We further …
Metal thin-film temperature sensor embedded in heat-sink for CPV cells characterization
2014
The efficiency of a photovoltaic cell is dependent on its temperature, for this reason an accurate measurement of this parameter is important to fully characterize the device and to optimize its performance. For CPV applications a significant heat flux is needed to remove excess heat from the cell towards a heat sink, making it difficult to derive the cell temperature. In fact, measurements performed directly between the cell and the heat-sink, by use of commercial bulk sensors, would produce a significant disturbance in the heat flow; on the other hand, a measurement performed out of the cell / heat sink axis would be subject to large uncertainties, due to the high radial temperature gradi…
Effects of the cycling workload on core and local skin temperatures
2016
[EN] Purpose: The aim of the study was to determine the influence of cycling workload on the variation of core and skin temperature of the different body regions, and the relationship between both temperature variables. Method: Fourteen cyclists performed two 45-min cycling tests at 35% and 50% of peak power output on different days. The cadence was constant in both tests (90 rpm). Core temperature was measured continuously throughout the test and local skin temperature was recorded before, immediately after and 10 min after finishing the cycling test. Differences in variation of the core and skin temperature and in the effort perception and body mass loss due to different cycling workload …
Multiphysical modeling of dissimilar welding via interlayer
2011
Abstract A multiphysical finite element modeling of dissimilar welding via interlayer material was proposed. A 2D model including heat transfer, fluid flow and level set problems allowed to simulate the morphology and the composition of melted zone in horizontal plane. The calculated thickness of melted interlayer was used as a main criterion for the choice of optimal welding conditions, when the chemical interaction between the joined materials must be avoided. A 1D diffusion model at the limit of melted zone allowed estimating the length and the composition of diffusion layer between one of the materials and the interlayer basing on previously calculated local temperature gradient. The si…
Thermoelectric current and magnetic field interaction influence on the structure of directionally solidified Sn-10 wt.%Pb alloy
2013
International audience; In this experimental work Sn-10 wt.% Pb alloy is directionally solidified in Bridgman setup at various growth velocities (from 0.5 mu m/s to 20 mu m/s) under transverse 0.4 T magnetic field. Temperature gradient of 8 K/mm is maintained perpendicular to the solidification direction during experiments. Liquid phase convection and its influence on the structure and segregation of an alloy, caused by magnetic field and thermoelectric current interaction (thermoelectromagnetic convection or TEMC) is studied experimentally and estimated theoretically in this work. Detailed velocity order of magnitude estimation is carried out. Besides optical microscopy, component distribu…