Flux pinning effect of cubic equiaxed morphology and its Ti stabilizing in Nb<Subscript>3</Subscript>Sn superconductors

Two sets of internal-Sn Nb3Sn superconducting strands were fabricated through RRP method, one with 2 wt% of Ti alloyed in Sn core and the other just pure Sn. Four reaction temperatures of 650℃, 675℃, 700℃ and 725℃ and 128 h duration were applied for A15 phase formation heat treatment after Cu-Sn alloying procedure of 210℃/50 h + 340℃/25 h. For the heat-treated coil samples, transport non-Cu JC was examined through standard 4-probe technique and phase microstructure was observed by means of Field Emission Sc...     

Scheduling evacuation operations

In this paper, we consider a large-scale evacuation problem after a major disaster. The evacuation is assumed to occur by means of a fleet of buses, thus leading to scheduling the evacuation operations by buses [(bus evacuation problem (BEP)]. We propose time-indexed formulations as well as heuristic algorithms such as greedy algorithms and a matheuristic. This matheuristic uses the former formulation to improve the best solution obtained by the greedy heuristics. In computational experiments, we analyze and evaluate the efficiency of the proposed solution algorithms.     

About classical logic and imperative programming

We consider a -calculus system in second-orderclassical logic, in which execution of -terms is weak head reduction (call-by-name). By means of some simple examples, we show how it can modelize some aspects of imperative programming languages, such as assignment and escape instructions. A crucial tool is the notion ofstorage operator, for which a simple type is given.     

Étude de la précision de l’estimation de la densité spectrale de puissance croisée,obtenue par transformation de fourier de la fonction de corrélation

The authors compare two different estimators of the crosscorrelation function and show that they give equivalent estimators in the frequency domain. They calculate the first and second order moments of the estimator of the cross-spectral-density (DSPC)due to the statistical errors and the quantification of inputs. From these general formulas, they perform numerical calculations for a particular case and they compare them to practical measurements. They show the interesting fact, that the variance of the statistical errors on the dspc is inferior by estimating its phase than by estimating its module. Furthermore, the quantification of the inputs may influence the variance of the phase of the DSPC estimated.     

A land cover classification product over France at 1 km resolution using SPOT4/VEGETATION data

The present study focuses on the development of a new land cover classification product over France at 1 km resolution. It is based on data sets from the Earth observing system SPOT4/VEGETATION. The satellite measurements are aimed at supporting regional efforts to set up global mosaics on new land cover products. They have been acquired in the frame of the Global Land Cover 2000 project. The instrument design relies on advanced technology, which leads to an improved radiometric and geometric resolution data. Such characteristics allow taking full benefit of the daily repetitiveness of the VEGETATION wide field-of-view sensor without the drawback of a variable pixel size on the image edge. Several physical processing steps are successively operated to the images on a per-pixel basis to remove detector blindness, to filter cloud contamination, and finally to correct both atmospheric and surface anisotropy effects. A new thematic map using the K-means clustering method has been built. First, the results of the satellite-based land cover classification has been successfully compared with the Coordination of Information on the Environment (CORINE) database which serves as a reference to appraise the reliability of the study. Then, it has been inter-compared with land cover products derived from MODIS and AVHRR sensors. For this, an aggregative scheme particularly focused on major land units (forest, grassland, cropland) adopted in order to yield a whole mapping at the same geographic projection and space resolution. The discrepancies between maps enhance the quality of the proposed product, thanks to the use of advanced data processing and a more appropriate method.     

Compactness of the Cement Microstructure Versus Crack Bridging in Mortars Reinforced with Amorphous Cast Iron Fibers and Silica Fumes

Both mechanical compaction and addition of pozzolanic silica fumes can provide low permeability interfacial transition zones around the fibers which reinforce a mortar matrix. This paper deals with the controversial effect of achieving a higher matrix compactness and its influence on the fracture behaviour of a mortar reinforced with amorphous cast iron fibers. Test were conducted in uniaxial tension on notched composite mortar prisms in order to plot load versus crack opening curves and evaluate the bridging energy provided by the fibers across a single opening crack. These measures were correlated to SEM observations of the microstructure of fiber/mortar interface, depending on the compaction energy and/or the mortar composition. It is relatively difficult to establish a compromise between ductility and high performance in terms of durability for the material system tested. Indeed, fibers were pulled out of low compactness mortars exhibiting large porous interfacial transition zones (ITZs) along the fiber surface. These zones mainly comprised fibrillous CSH, ettringite and large portlandite crystals. Conversely, when the ITZs around the fibers where filled with compact CSH, resulting from the pozzolanic reaction between silica fume and portlandite, no fiber slippage was observed, but the reinforced mortar broke in a quasi-brittle manner.     

How to Attain Ultralow Interfacial Tension and Three-Phase Behavior with Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 4: Robustness of the Optimum Formulation Zone Through the Insensibility to Some Variables and the Occurrence of Complex Artifacts

In enhanced oil recovery, not only the low-tension performance, but also the robustness at optimum formulation is an important issue. The fourth part of our review series is dedicated to robustness, defined as the width of the zone exhibiting three-phase behavior around the optimum formulation, whatever the scanned variable. It is first corroborated from a screening of the available data in the literature that the tension minimum is inversely proportional to the square of the three-phase range in the HLD scale. However, since there is still an inaccuracy of about a factor 10 in the tension minimum, some significant improvement can be attained in some cases by increasing the three-phase behavior width in two ways. The first approach consists of finding systems that are insensitive to some formulation variable such as temperature, surfactant mixture composition or concentration, and water-to-oil ratio. The second way is to produce an artifact through which the optimum formulation is produced twice in a scan. If the distance between the two events in the scan is reduced down to be zero, their corresponding three-phase behavior zones merge and result in a wider WIII region with a low tension. Several cases of such events are reported: alkaline scans, anionic-nonionic and anionic-cationic mixture changes, linear change in composition in three-surfactant mixture, partial precipitation from a surfactant mixture in a salinity scan, and excessive partitioning of polyethoxylated nonionics. More complex transitions with three effects in a single scan or three concomitantly scanned variables show even more possibilities in practice.     

The optimization of gamma spectra processing in prompt gamma neutron activation analysis (PGNAA)

The uncertainty of the elemental analysis is one of the major factors governing the utility of on-line Prompt Gamma Neutron Activation Analysis (PGNAA) in the blending and sorting of bulk materials. In this paper, a general method applicable to Gamma spectra processing is presented and applied to PGNAA in mineral industry. Based on the Fourier transform of spectra and their de-correlation in the Fourier space (the improvement of the conditioning of the correlation matrix), processing of overlapping of characteristic peaks minimizes the propagation of random errors, which optimizes the accuracy and decreases the detection limits of elemental analyses. In comparison with classical methods based on the linear combinations of relevant regions of spectra the improvement may be considerable, especially when several elements are interfering. The method is applied to four case stories covering both borehole logging and on-line analysis on conveyor belt of raw materials.