Search results for "Structural evolution"

Reply to comments by A. Krohe and A.P. Willner on “Structural evolution of the central part of the Krušné Hory (Erzgebirge) Mountains in the Czech Re…

2003

Effect of thermal treatment on the structural evolution of 3:2 and 2:1 mullite monophasic gels

2005

Abstract Single phase mullite gels with composition 3Al2O3 · 2SiO2 (3:2) and 2Al2O3 · SiO2 (2:1) were prepared by the semialkoxide method using aluminum nitrate nonahydrate and tetraethylorthosilicate as reagents. The influence of the thermal processing conditions on the reaction sequence was investigated. Both 3:2 and 2:1 mullite gels formed orthorhombic mullite under fast heating (40 °C/min) at 900 °C. Slow heatings delayed the formation of mullite in both gel compositions but no formation of spinel was detected between 1000 °C and 1100 °C. The slow transformation of pentacoordinated aluminum to octahedral and tetrahedral arrangements probably depends on the larger size and extent of the …

Water retention behaviour and microstructural evolution of MX-80 bentonite during wetting and drying cycles

2014

MX-80 bentonite used in engineered barrier systems would be subjected to wetting and drying cycles. To assess the response of the material under such circumstances, a comprehensive experimental characterisation of the water retention behaviour of compacted MX-80 granular bentonite was performed in this study. A new methodology is proposed to investigate this behaviour under a constant volume condition for specimens prepared at different dry densities. The material was subjected to different hydraulic paths, including cyclic variations of the water content. As a result, an irreversible modification of the retention behaviour was observed when the material approached a fully saturated state …

Additive manufacturing Processing and characterization of Fe-Si soft magnetic alloys

2021

Iron silicon (Fe-Si) alloys, also named silicon steels, are the most widely used owing to their excellent soft magnetic properties and economic costs. As electronic devices become diversified and automated, it is urgent to develop high-performance soft magnetic alloys with good reliability. For functional soft magnetic alloys, the SLM technique shown the potential to manufacture soft magnetic components directly from raw materials, such as the rotor and stator of the motor. In order to explore and develop new routes for manufacturing Fe-Si alloys, the investigation into the microstructures and properties of SLMed Fe-Si alloys from pre-alloyed powders was presented in this work. The most imp…

A Framework of Microtectonic Studies

1998

From their first use in the last century, thin sections of rocks have been an important source of information for geologists. Many of the older textbooks on structural geology, however, did not treat microscopic aspects of structures, while petrologists would describe microscopic structures as, for example, lepidoblastic or nematoblastic without paying much attention to kinematic and dynamic implications. During the last decades, however, structural geologists learned to profit from the wealth of data that can be obtained from the geometry of structures studied in thin section, and metamorphic petrologists have appreciated the relation of structural evolution on the thin section scale and m…

Gamow-Teller response in deformed even and odd neutron-rich Zr and Mo isotopes

2014

13 pags. ; 17 figs. ; PACS number(s): 21.60.Jz, 23.40.Hc, 27.60.+j, 26.30.−k

Microstructural evolution and growth of crystallite size of mullite during thermal transformation of kyanite

1997

Abstract The microstructural evolution of mullite during the thermal transformation of kyanite has been studied in the temperature range 1200–1600 °C. The shape and size of the grains were analysed by means of SEM-EDS while crystallite size evolution was studied by X-ray line profile analyses. The results obtained showed that total transformation of kyanite to mullite takes place between 1350 and 1400 °C. At temperatures below 1350 °C needle-like mullite grains are always produced. At higher temperatures the mullite grains reveal rounded end platelet morphology. Evolution from needle-like to platelet shape was correlated with the X-ray data.

Structure evolution and reaction mechanism in the Ni/Al reactive multilayer nanofoils

2014

Abstract The extremely rapid gasless reactions in binary Ni/Al reactive multilayer nanofoils (RMNFs) are investigated both experimentally and theoretically. The quenching technique is used to study the dynamics of structural transformation on the micro- and nanoscales. The experimentally obtained patterns of structural evolution related to the heterogeneous reactions are compared with the results of molecular dynamics simulations carried out for the same reactive system. Based on the obtained data, the intrinsic mechanism of the reaction in Ni/Al RMNF is considered, which adequately explains the unusual parameters of a gasless combustion wave in such a system.

Dos inscripciones sobre la fundación de Lara y una sobre sus siete infantes, con un análisis evolutivo de su iglesia parroquial

2016

Se someten a crítica filológica e histórica tres inscripciones epigráficas procedentes de Lara de los Infantes que abordan el discutido tema del origen de Castilla. La factura de la más antigua, encontrada en la ermita de San Julián (en el Museode Burgos desde principios del siglo XX) se debió de redactar a mediados del siglo XII, en sintonía con el monasterio burgalés de San Pedro de Arlanza, pues resalta la preeminencia de este centro en su vínculo con Fernán González. Posiblemente se basó también en una tradición local lareña hoy perdida y, en todo caso, partiendo de noticias espurias. En época humanística, antes del año 1600, se realizó una copia de esta inscripción a la que se añadió o…

Impact of Superfinish Turning on Surface Integrity of Pure Copper

2011

Abstract The presented study deals with comprehension of relationships between machining cutting conditions and physical-chemical properties linked with surface integrity. A multi-physics model is presented to calculate residual stress, temperature and dislocation fields in the machined material. This model includes both thermal-mechanical, structural evolution and dynamic recristallisation approaches. The model was applied to pure copper after superfinish turning. Good agreement was found between numerical values and experimental ones. This paper also presents a work on the impact of mechanical and microstructural changes induced by machining on the electrochemical behaviour and corrosion …