Strain relaxation dynamics of multiferroic orthorhombic manganites.

Resonant Ultrasound Spectroscopy has been used to characterise strain coupling and relaxation behaviour associated with magnetic/magnetoelectric phase transitions in GdMnO3, TbMnO3 and TbMn0.98Fe0.02O3 through their influence on elastic/anelastic properties. Acoustic attenuation ahead of the paramagnetic colinear-sinusoidal/incommensurate/antiferromagnetic transition at ~41 K correlates with anomalies in dielectric properties and is interpreted in terms of Debye-like freezing processes. A loss peak at ~150 K is related to a steep increase in electrical conductivity with a polaron mechanism. The activation energy, Ea, of ≥ ~0.04 eV from a loss peak at ~80 K is consistent with the existence of a well-defined temperature interval in which the paramagnetic structure is stabilised by local, dynamic correlations of electric and magnetic polarisation that couple with strain and have relaxation times in the vicinity of ~10-6 s. Comparison with previously published data for Sm0.6Y0.4MnO3 confirms that this pattern may be typical for multiferroic orthorhombic RMnO3 perovskites (R = Gd, Tb, Dy). A frequency-dependent loss peak near 10 K observed for TbMnO3 and TbMn0.98Fe0.02O3, but not for GdMnO3, yielded Ea ≥ ~0.002 eV and is interpreted as freezing of some magnetoelastic component of the cycloid structure. Small anomalies in elastic properties associated with the incommensurate and cycloidal magnetic transitions confirm results from thermal expansion data that the magnetic order parameters have weak but significant coupling with strain. Even at strain magnitudes of ~0.1-1 ‰, polaron-like strain effects are clearly important in defining the development and evolution of magnetoelectric properties in these materials. Strains associated with the cubic - orthorhombic transition due to the combined Jahn-Teller/octahedral tilting transition in the vicinity of 1500 K are 2-3 orders of magnitude greater. It is inevitable that ferroelastic twin walls due to this transition would have significantly different magnetoelectric properties from homogeneous domains due to magnetoelastic coupling with steep strain gradients.This work was funded by EPSRC Grant No. EP/ P024904/1 (UK). RUS facilities were established through grants from the Natural Environment Research Council (Grants No. NE/B505738/1 and No. NE/F017081/1) and the Engineering and Physical Sciences Research Council (Grant No. EP/I036079/1) to MAC. The work at the University of Warwick was supported by EPSRC,UK through Grant EP/T005963/1

Large-Scale Streamwise Vortices in Turbulent Channel Flow Induced by Active Wall Actuations

© 2017, Springer Science+Business Media B.V., part of Springer Nature. Direct numerical simulations of turbulent flow in a plane channel using spanwise alternatively distributed strips (SADS) are performed to investigate the characteristics of large-scale streamwise vortices (LSSVs) induced by small-scale active wall actuations, and their role in suppressing flow separation. SADS control is obtained by alternatively applying out-of-phase control (OPC) and in-phase control (IPC) to the wall-normal velocity component of the lower channel wall, in the spanwise direction. Besides the non-controlled channel flow simulated as a reference, four controlled cases with 1, 2, 3 and 4 pairs of OPC/IPC strips are studied at M = 0.2 and Re = 6,000, based on the bulk velocity and the channel half height. The case with 2 pairs of strips, whose width is Δz+ = 264 based on the friction velocity of the non-controlled case, is the most effective in terms of generating large-scale motions. It is also found that the OPC (resp. IPC) strips suppress (resp. enhance) the coherent structures and that leads to the creation of a vertical shear layer, which is responsible for the LSSVs presence. They are in a statistically steady state and their cores are located between two neighbouring OPC and IPC strips. These motions contribute significantly to the momentum transport in the wall-normal and spanwise directions showing potential for flow separation suppression

Phylogenetic and functional marker genes to study ammonia-oxidizing microorganisms (AOM) in the environment

The oxidation of ammonia plays a significant role in the transformation of fixed nitrogen in the global nitrogen cycle. Autotrophic ammonia oxidation is known in three groups of microorganisms. Aerobic ammonia-oxidizing bacteria and archaea convert ammonia into nitrite during nitrification. Anaerobic ammonia-oxidizing bacteria (anammox) oxidize ammonia using nitrite as electron acceptor and producing atmospheric dinitrogen. The isolation and cultivation of all three groups in the laboratory are quite problematic due to their slow growth rates, poor growth yields, unpredictable lag phases, and sensitivity to certain organic compounds. Culture-independent approaches have contributed importantly to our understanding of the diversity and distribution of these microorganisms in the environment. In this review, we present an overview of approaches that have been used for the molecular study of ammonia oxidizers and discuss their application in different environments

The effects of dietary neutral detergent fiber ratio on the rumen degradability and growth performance of Philippine native goats (Capra hircus Linn.)

This research’s objective was to determine the dietary rumen degradability and growth performances of goats fed dietary treatments. Eighteen (18) female goats were grouped into 6 weight classes for the feeding trial experiment, the average BW of the animals that were used was about 7.96 ± 2.21 kg (CV - 27.76%) and were approximately 1 year of age. For the in situ digestibility, three (3) male mature goats surgically fitted with cannulated rumen were used. Three (3) dietary treatments were used for all studies as follows: T1 - 72 : 28 NDF Forage-Concentrate Ratio; T2 - 64 : 36; T3 - 57 : 43. A RCBD was applied for Feeding Trial and a 3 x 3 LSD was used for In Situ Study. Treatments 1, 2 and 3 did not affect the rate of rumen degradability of DM, NDF and CP at 0 hours, potentially degradable fraction (b) and the rate of degradation of b. The treatments affected the intake rate of forage and concentrates on the DM, CP and NDF. However, the total intake of DM, CP and NDF were not affected by the treatments. Growth performance of goats used in this experiment was not affected by the treatments as indicated by the similar production and efficiency. This means that diets given to native goats with ratio of NDF forage of 72.07% can be applied since the value of the output and efficiency of feed utilization had the same value compared to diets ratio of NDF forage of 57.21%

ANALYSIS OF SAW WELDING PROCESS IN PRESSURE VESSEL TANK FOR AMMONIA FLUID WITH PRESSURE CAPACITY OF 13 Pa

Pressure vessels are widely used to accommodate pressurized fluids, one of which is to accommodate ammonia with a working pressure of 13 Pa. Pressure vessels use ASTM A516 Grade 70 as raw material. This material has the advantage of being resistant to changes in temperature and good weldability. To make this equipment, a lot of joining processes are used, because the welding process is unavoidable in the construction of joints and the manufacture of processing equipment made of stainless steel. Of the many metal materials, ASTM A516 Gr 70 because of its low carbon content thereby avoiding the possibility of sensitization of the welded components, has good weldability properties because it has high temperature resistance. There are many ways of connecting with welding techniques, one of which is using the Submerged Arc Welding (SAW) technique. (SAW) is a welding process using a submerged arc in flux. The function of the flux is to prevent oxidation, as an alloying element in the chemical composition of the weld metal, as a stabilizer, and as an oxidizer. The welding carried out in this study uses current variations, including 350 A. , 400 A, 410 A san 430 A . Next, a test is carried out from the results of the welding process such as a tensile test tap test. From the test results, it is obtained that the current strength value is suitable to be recommended for the welding process, namely at a current of 400 A seen from the value of the tensile test results and the hardness test.   Keywords : Pressure vessel, ASTM A516 Gr 70, SAW weldin

L errance dans l oeuvre de Meddeb entre islam, soufisme et Occident (lecture d un interculturel du possible)

Cette recherche propose une analyse du rapport interculturel entre l'islam et l Occident à travers la thématique de l'errance dans l'oeuvre d Abdelwahab Meddeb. Nous voulons montrer la corrélation entre l errance et l interculturalité, en nous nous appuyant sur trois axes dégagés dans l'oeuvre de Meddeb : l'autobiographie, l'écriture et l'islam et le soufisme. L'interculturalité est portée par le personnage même de l'auteur, à travers la double généalogie, arabo-musulmane et occidentale, et dont les deux pôles sont Ibn 'Arabi et Dante, ce qui nous conduit à examiner l inscription autobiographique dans l'oeuvre de Meddeb sous le prisme de l'errance. Cette analyse nous a permis de relever l hétérogénéité de cette autobiographie. En exhibant les multiples composantes de la personnalité du personnage de son oeuvre, Meddeb veut souligner que l'identité est composite et non monolithique, qu'elle n est point figée, mais en devenir. La généalogie cosmopolite du personnage entraîne une écriture fondée sur l errance. Il convient de voir, comment le récit circule entre plusieurs références ; linguistiques, culturelles et religieuses. Mû par sa double généalogie, le narrateur circule entre ses différentes appartenances, ses différentes références pour y puiser la matière et le matériau de son écriture. Cette porosité identitaire du personnage nous permet par exemple, d analyser l'évocation du vin à l aune de la mystique soufie. Enfin, nous proposons, à partir de l'oeuvre de Meddeb, une lecture de l'islam et du soufisme en rapport avec l errance. A travers des exemples précis tirés de l'oeuvre de Meddeb et des textes coranique et soufis nous avons observé que la religion mahométane et sa mystique sont nourries dès leurs racines par la sève de l'errance, de la cosmogonie aux pratiques rituelles, tout converge vers l'errance. Étant bâtis donc dans et autour de l errance, l'islam et le soufisme, sont prédisposés à l épreuve de l'interculturelThis paper will examine the intercultural link between Islam and the West through the notion of wandering in Abdelwahab Meddeb s work. The correlation between errance and interculturality will be explored under three perspectives taken from Meddeb s work: autobiography, writing and tasawwuf. The very author personifies interculturality with his dual-genealogy, Arab-Muslim and Western. His two centers are Ibn Arabi and Dante, hence the interest of the autobiographic inscription and the notion of errance in his work. This perspective reveals the heterogeneity of this autobiography. Meddeb exhibits the multiple components of his character s personality and thereby underlines how the essence of identity evokes mixed origins. Identity is not qualified as monolithic but rather as becoming and moving. The character s cosmopolite genealogy leads to the inscription of errance in the writing process. How does the narrative evolve through linguistic, cultural and religious references? Driven by his dual-genealogy, the narrator draws his writing material from his different senses of belonging and references. For instance, the character s porous identity enables us to analyze the evocation of wine at the standpoint of mystic Sufism. A reading of Islam and Sufism will finally be offered in relation with errance . Precise examples taken from Meddeb s work as well as texts from Sufism and the Koran demonstrate how errance fills the Mahometan religion. From cosmogony to concrete rituals, all seems to converge towards errance . Therefore built within and around errance , Islam and Sufism seem particularly adapted to the trial of interculturalityRENNES2-BU Centrale (352382101) / SudocSudocFranceF