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Vitrification of TRISO-coated gas reactor fuel particles was achieved via two methods: glass melting and sintering. Inert TRISO-coated fuel particles and a borosilicate glass were used. With glass melting at 1200-1300 °C floatation and decomposition of carbon and silicon carbide occurred. Thermal pre-treatment of the particles for oxidation of pyrocarbon did not improve the coating properties of the glass. During cooling most of the particles floated and sorbed on the crucible or mold walls. The sintered glass at 700 °C showed better coating properties of the TRISO-coated fuel particles despite higher porosity compared to glass made by melting. Aqueous leaching properties of glass with particles are similar regardless the mode of fabrication, indicating the good chemical durability of the sintered glass. Sintered glasses may constitute a good technique for TRISO-coated fuel particles immobilization for an eventual deep geological disposal. 相似文献
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Abba Bala Namata Idouhli Rachid Ilagouma Amadou Tidjani Abouelfida Abdesselam Khadiri MohyEddine Romane Abderrahmane 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(3):619-633
Protection of Metals and Physical Chemistry of Surfaces - In the present study, we evaluated the effect of corrosion inhibition of ethanol extracts from Endostemon tereticaulis and Hyptis spicigera... 相似文献
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Abdesselam Benjelloun Christine Damas Alain Brembilla Pierre Lochon 《Polymer Bulletin》1994,33(5):513-520
Summary We report on the preparation and the characterization of R-alkylated quaternary salts (with RCCH3, C12H25, C16H33, X=Br-) derived from 3-vinylpyridine (3-VP). Our first attempts on free radical polymerization of 1-hexadecyl-3-vinylpyridinium bromide in benzene solution were described. The viscosimetric behaviour and binding of dye (Methyl Orange) to this homopolymer in aqueous media were interpreted as the formation of compact coils resulting in the presence of hydrophobic microdomains. 相似文献
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Phung SL Bouzerdoum A Chai D 《IEEE transactions on pattern analysis and machine intelligence》2005,27(1):148-154
This work presents a study of three important issues of the color pixel classification approach to skin segmentation: color representation, color quantization, and classification algorithm. Our analysis of several representative color spaces using the Bayesian classifier with the histogram technique shows that skin segmentation based on color pixel classification is largely unaffected by the choice of the color space. However, segmentation performance degrades when only chrominance channels are used in classification. Furthermore, we find that color quantization can be as low as 64 bins per channel, although higher histogram sizes give better segmentation performance. The Bayesian classifier with the histogram technique and the multilayer perceptron classifier are found to perform better compared to other tested classifiers, including three piecewise linear classifiers, three unimodal Gaussian classifiers, and a Gaussian mixture classifier. 相似文献
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Abdesselam Abdelouas Yassine El Mendili Abdelouahed Aït Chaou Gokhan Karakurt Christoph Hartnack Jean-François Bardeau Takumi Saito Hiroyuki Matsuzaki 《International Journal of Applied Glass Science》2013,4(4):307-316
During the geological disposal of high-level waste, the nuclear glass is expected to be first hydrated in water vapor prior to liquid alteration. In the present work, we investigated the vapor hydration of the International simple glass (ISG) at 175°C and different relative humidities (60%, 80% and 98%). The glass hydration was investigated by nuclear reaction analysis (NRA) and Fourier transform infra-red spectroscopy. The chemical and mineralogical compositions of the alteration products were studied using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS) and μ-Raman spectroscopy, respectively. The NRA results gave water diffusion coefficients of 2.31–7.34 × 10−21 m2/s, in good agreement with the literature data on borosilicate glasses altered in aqueous media. The glass hydration increased with relative humidity percentage and the SEM-EDS analysis showed a slight enrichment in Si and loss of Na in the hydrated glass layer compared with the pristine glass. The hydration rate of the ISG glass was little higher than that of the French SON68 glass hydrated using water vapor. The corrosion products were analcime, tobermorite, and calcite, which were typical of the SON68 glass hydrated in similar conditions. 相似文献
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Xiaobo Zhang Heping Wang Farid Nait‐Abdesselam Ashfaq Khokhar 《Wireless Communications and Mobile Computing》2009,9(10):1360-1368
In several wireless sensor network applications, it is required to perform real‐time reconstruction of the data field being sensed by the network. This task is generally carried out at a central location, e.g. sink node, using a continuous data gathering phase and relying on the known correlation properties of the underlying data field. Estimating the overall spatial and temporal distortion in the reconstructed field is an important step toward deciding the number of sensors to be deployed and the data collection algorithm to be used. However, estimating distortion in arbitrary networks is a challenging task. Existing work has focused on regular network deployments such as one‐ and two‐dimensional girds. Such deployments are deemed infeasible in a realistic environment. In this paper, we consider one‐ and two‐dimensional random networks. For the analysis purposes, we assume that the nodes are randomly deployed following Poisson distribution. We determine the total distortion function given the correlation coefficients of the field while assuming a simple data gathering protocol. Based on this, we also determine the optimal number of nodes to be deployed in the field that will minimize distortion. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Abdesselam Lakehal Ioannis Parissis 《Software Testing, Verification and Reliability》2009,19(2):133-154
LUSTRE is a data‐flow synchronous language, on which is based the SCADE tool‐suite, widely used for specifying and programming critical reactive applications in the areas of avionics, energy or transport. Therefore, testing LUSTRE programs, that is, generating test data and assessing the achieved test coverage, is a major issue. Usual control‐flow‐based test coverage criteria (statement coverage, branch coverage, etc.) are not relevant for LUSTRE programs. In this paper, a new hierarchy of adequacy criteria tailored to the LUSTRE language is presented. These criteria are defined on operator networks, which are usual models for LUSTRE programs. The criteria satisfaction measure is automated in LUSTRUCTU , a non‐intrusive tool (no instrumentation of the code), based on the symbolic computation of path activation conditions. The applicability and the relevance of the criteria are assessed on a case study. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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The alteration of SON68 glass (inactive R7T7 type nuclear waste glass) was studied to measure the long-term residual dissolution rate under different conditions. Experiments were conducted in flow-through conditions (solution flow rate 3-5 mL/day) at pH 8.0, 9.5, and 10.5 under various initial Si concentrations, a glass surface-to-volume ratio near 14,000 m−1 and at a temperature of 90 °C. This set of long-term experiments (200 days) showed leaching rates dependent on the initial silica concentration and the initial pH. Interpretation of results at pH 8.0 was difficult due to the use of a synthetic water used to represent waters found at a potential French repository site. Because very small glass powder sizes were used (Ø = 1 μm), a complete dissolution of the pristine glass was achieved at low initial silica concentrations where higher leaching rates were produced. In all cases, initial high normalized leaching rates were observed followed by a decrease in leaching rate with rate levels ranging from 9 (±4) to 5 (±3) × 10−4 g m−2 d−1 at 200 days under silica saturated conditions at pH 9.5 and 10.5, respectively. We have compared these results to previous results obtained in similar leaching conditions. Modeling using the GM2004 model program and model output values were shown to be in agreement with experimental results. 相似文献
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M. Abdesselam M. Azzouz M. Siad 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(18):3899-3905
The stopping cross sections ε(E) of silicon for protons and alpha particles have been measured over the velocity range 0.3-1.2 MeV/u from a Si//SiO2//Si (SIMOX) target using the Rutherford backscattering spectrometry (RBS) with special emphasis put on experimental aspects. A detection geometry coupling simultaneously two solid-state Si detectors placed at 165° and 150° relative to each side of the incident beam direction was used to measure the energies of the scattered ions and determine their energy losses within the stopping medium. In this way, the basic energy parameter, Ex, at the Si/SiO2 interface for a given incident energy E0 is the same for ions backscattered in the two directions off both the Si and O target elements, and systematic uncertainties in the ε(E) data mainly originating from the target thickness are significantly minimized. A powerful computer code has been elaborated for extracting the relevant ε(E) experimental data and the associated overall uncertainty that amounts to less than 3%. The measured ε(E) data sets were found to be in fair agreement with Paul’s compilation and with values calculated by the SRIM 06 computer code. In the case of 4He+ ions, experimental data for the γ effective charge parameter have been deduced by scaling the measured stopping cross sections to those of protons crossing the same target with the same velocity, and compared to the predictions of the SRIM 06 computer code. It is found that the γ-parameter values generated by the latter code slightly deviate from experiment over the velocity region around the stopping cross section maximum where strong charge exchanges usually occur. 相似文献