Durability of self-compacting concretes made with the natural pozzolan and siliceous fines

The effect of natural pozzolan and local waste siliceous fines on the durability of SCC was studied in this paper. Three self-compacting concretes were made with the following three additions, namely limestone fillers (SCC LF), pozzolanic fillers (SCC NP) and siliceous fillers (SCC SF). Durability tests, such as the porosity accessible to water, capillarity, carbonation, permeability to oxygen gas and diffusion of chloride ions, were carried out on these concretes in order to study the influence of these fillers on the transfer properties and durability of SCCs. The results obtained indicate that the SCC LF and SCC NP generally have the same transfer properties; these properties are significantly influenced by porosity and carbonation. In addition, the capillarity is nearly similar for all three SCCs. Moreover, it is worth noting that SCC NP gives permeability and diffusion coefficients of chloride ions slightly lower in comparison with those of the other SCCs. These finding suggest that the incorporation of Algerian natural fines and industrial waste as mineral additions into the SCC may have a positive environmental impact and can promote the development of local materials that are available in large quantities and whose production cost is low

Durability of self-compacting concretes made with the natural pozzolan and siliceous fines

The effect of natural pozzolan and local waste siliceous fines on the durability of SCC was studied in this paper. Three self-compacting concretes were made with the following three additions, namely limestone fillers (SCC LF), pozzolanic fillers (SCC NP) and siliceous fillers (SCC SF). Durability tests, such as the porosity accessible to water, capillarity, carbonation, permeability to oxygen gas and diffusion of chloride ions, were carried out on these concretes in order to study the influence of these fillers on the transfer properties and durability of SCCs. The results obtained indicate that the SCC LF and SCC NP generally have the same transfer properties; these properties are significantly influenced by porosity and carbonation. In addition, the capillarity is nearly similar for all three SCCs. Moreover, it is worth noting that SCC NP gives permeability and diffusion coefficients of chloride ions slightly lower in comparison with those of the other SCCs. These finding suggest that the incorporation of Algerian natural fines and industrial waste as mineral additions into the SCC may have a positive environmental impact and can promote the development of local materials that are available in large quantities and whose production cost is low

An ultra-thin diamond membrane as a transmission particle detector and vacuum window for external microbeams

Several applications of external microbeam techniques demand a very accurate and controlled dose delivery. To satisfy these requirements when post-sample ion detection is not feasible, we constructed a transmission single-ion detector based on an ultra-thin diamond membrane. The negligible intrinsic noise provides an excellent signal-to-noise ratio and enables a hit-detection efficiency of close to 100%, even for energetic protons, while the small thickness of the membrane limits beam spreading. Moreover, because of the superb mechanical stiffness of diamond, this membrane can simultaneously serve as a vacuum window and allow the extraction of an ion microbeam into the atmosphere

Glueball production in radiative J/psi, Upsilon decays

Using a bound-state model of weakly bound gluons for glueballs made of two gluons and a natural generalization of the perturbative QCD formalism for exclusive hadronic processes, we present results for glueball production in radiative J/psi, Upsilon decays into several possible glueball states, including L \not= 0 ones. We perform a detailed phenomenological analysis, presenting results for the more favored experimental candidates and for decay angular distributions.Comment: RevTeX4, 26 pages, 11 eps figure

Charge multiplication effect in thin diamond films

Herein, we report on the enhanced sensitivity for the detection of charged particles in single crystal chemical vapour deposition (scCVD) diamond radiation detectors. The experimental results demonstrate charge multiplication in thin planar diamond membrane detectors, upon impact of 18MeV O ions, under high electric field conditions. Avalanche multiplication is widely exploited in devices such as avalanche photo diodes, but has never before been reproducibly observed in intrinsic CVD diamond. Because enhanced sensitivity for charged particle detection is obtained for short charge drift lengths without dark counts, this effect could be further exploited in the development of sensors based on avalanche multiplication and radiation detectors with extreme radiation hardnes

Mass corrections in J/ψ→BBˉJ/\psi \to B\bar B decay and the role of distribution amplitudes

We consider mass correction effects on the polar angular distribution of a baryon--antibaryon pair created in the chain decay process $e^-e^+ \to J/\psi \to B\bar B$, generalizing a previous analysis of Carimalo. We show the relevance of the features of the baryon distribution amplitudes and estimate the electromagnetic corrections to the QCD results.Comment: 26 pages + 3 figures, REVTEX 3.0, figures appended as uuencoded, tar-compressed postscript fil