Search results for "microstructure"
showing 10 items of 707 documents
Contagion in Bitcoin Networks
2019
12 pages, 6 figures. Paper accepted in 2nd Workshop on Blockchain and Smart Contract Technologies (BSCT 2019), workshop satellite of 22nd International Conference on Business Information Systems (BIS 2019); International audience; We construct the Google matrices of bitcoin transactions for all year quarters during the period of January 11, 2009 till April 10, 2013. During the last quarters the network size contains about 6 million users (nodes) with about 150 million transactions. From PageRank and CheiRank probabilities, analogous to trade import and export, we determine the dimensionless trade balance of each user and model the contagion propagation on the network assuming that a user go…
Microstructure–property relation and machine learning prediction of hole expansion capacity of high-strength steels
2021
Abstract The relationship between microstructure features and mechanical properties plays an important role in the design of materials and improvement of properties. Hole expansion capacity plays a fundamental role in defining the formability of metal sheets. Due to the complexity of the experimental procedure of testing hole expansion capacity, where many influencing factors contribute to the resulting values, the relationship between microstructure features and hole expansion capacity and the complexity of this relation is not yet fully understood. In the present study, an experimental dataset containing the phase constituents of 55 microstructures as well as corresponding properties, su…
Quantitative phase analysis and thickness measurement of surface-oxide layers in metal and alloy powders by the chemical-granular method
1998
The principles of the chemical-granular analysis of metal and alloy powders are reviewed and the results are compared with those provided by the spectroscopic analytical techniques XPS, AES and SIMS, including ion etching in their depth-profiling mode, when they are applied to the same materials. Several examples are analysed and it is shown that the chemical-granular method alone can provide the very same information as depth profiling. However, it is averaged over a macroscopic powder sample in contrast to one or a few single particles. Nevertheless, it is the combination of the chemical-granular and depth-profiling analyses that really provides an unparalleled description in quantitative…
Commercial thickeners used by patients with dysphagia: Rheological and structural behaviour in different food matrices
2015
In order to achieve a safe swallowing in patients with dysphagia, liquids must be thickened. In this work, two commercial starch based thickeners dissolved inwater,whole milk, apple juice and tomato juice were studied. The thickeners were Resource®, composed of modified maize starch and Nutilis®, composed of modified maize starch and gums. They were formulated at two different concentrations corresponding to nectar- and pudding-like consistencies. Influence of composition, concentration and food matrix on rheological properties and structure of the resulting pastes were analysed. Viscoelastic measurements and microscopic observations of the thickeners dissolved in water revealed structural …
P-T path development derived from shearband boudin microstructure
2016
This work focuses on the development of a regional P-T-path from the Malpica-Lamego Ductile Shear Zone, NW Portugal, based on the microstructures of shearband boudins evolved during progressive simple shear. The combination of microstructural analysis, fluid inclusion studies, crystallographic pre- ffered orientation and fractal geometry analyses, allows to link several stages in the internal evolution of the boudin to regional P-T conditions. The boudinage process is initiated under differential stress after the original layer achieved sufficient viscosity contrast relative to the surrounding matrix. Two main transformations occur simultaneously: i) change in the external shape with contin…
Magnesium alloys laser (Nd:YAG) cladding and alloying with side injection of aluminium powder
2003
International audience; The development of the high purity magnesium alloys (such as WE43) incites the designers to reconsider them, and the car industry appears, these days, the most interested to use this kind of alloy. However, due to their ignitability and tendency to oxidation, magnesium alloys require surface treatments. A series of experiments was carried out in order to improve the corrosion resistance of two types of magnesium alloys, WE43 and ZE41. In most cases, the substrate surface was treated before laser interaction. Side injection of aluminium powder under a 3 kW cw Nd:YAG laser was employed. The deposited layers present very good bond properties. The resulting microstructur…
Magnesium alloys (WE43 and ZE41) characterisation for laser applications
2004
International audience; One of the most important parameters in laser treatment is the quantity of beam energy absorbed by the substrate. Despite its important role played in laser processes, this factor is rarely available for the laser sources wavelengths and at high temperatures reached during such treatments. A series of experiments were carried out in order to characterise, from this point of view, two types of magnesium alloys, WE43 and ZE41, often used in laser applications (cladding, alloying, welding, etc.). The results represent an important step in order to understand Mg-alloys behaviour under laser beam action.
MoSi2 laser cladding—A new experimental procedure: double-sided injection of MoSi2 and ZrO2
2003
International audience; In the last decade, development of low density advanced material systems for service at temperatures up to 1300 °C was one of the goals of many researches. This kind of material should mainly have moderate fracture toughness and should exhibit oxidation resistant behaviour at low and intermediate temperature. One of the most studied materials continues to be the intermetallic compound MoSi2. The molybdenum disilicide has been considered as an attractive candidate due to its melting point (2030 °C) and excellent oxidation resistance at high temperatures. The main problem associated with the MoSi2 layer synthesized using laser beam is the layer fragility. To avoid this…
Microstructural evolution of gas hydrates in sedimentary matrices observed with synchrotron X-ray computed tomographic microscopy
2015
The formation process of gas hydrates in sedimentary matrices is of crucial importance for the physical and transport properties of the resulting aggregates. This process has never been observed in situ at submicron resolution. Here we report on synchrotron-based microtomographic studies by which the nucleation and growth processes of gas hydrate were observed at 276 K in various sedimentary matrices such as natural quartz (with and without admixtures of montmorillonite type clay) or glass beads with different surface properties, at varying water saturation. Both juvenile water and metastably gas-enriched water obtained from gas hydrate decomposition was used. Xenon gas was employed to enha…
Modeling the Probability of Informed Trading in the European Carbon Market
2012
We provide evidence of informed trading in the European carbon market. We adapt Easley et al.’s (1996) PIN methodology to the particularities of this market by isolating the trading activity on the two carbon offsets: European Union Allowances (EUAs) and Certified Emission Reductions (CERs). We find that the PIN regularly increases before the publication of the yearly verified-emission reports. CERs exhibit lower average PIN than EUAs. While the PIN of CERs has increased over time, together with its share in total trading activity, EUAs’ PIN has remained pretty stable. Our findings suggest that CERs must not be avoided in any decision or analysis made by researchers, regulators or traders i…