Wyniki wyszukiwania - Biblioteka Nauki

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Effect of NaOH Molar Concentration on Microstructure and Compressive Strength of Dolomite/Fly Ash-Based Geopolymers

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Azimi E. A. , Mohd Salleh M. A. A. , Al Bakri Abdullah M. M. , Aziz I. H. A. , Hussin K. , Chaiprapa J. , Vizureanu P. , Yoriya S. , Nabiałek M. , Wyslocki J. J.

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tom Vol. 67, iss. 3

993--998

EN

Dolomite can be used as a source of aluminosilicate to produce geopolymers; however, this approach is limited by its low reactivity. This study analyzes the viability of producing geopolymers using dolomite/fly-ash with sodium silicate and NaOH solutions (at multiple concentrations) by determining the resultant geopolymers’ compressive strengths. The dolomite/fly-ash-based geopolymers at a NaOH concentration of ~22 M resulted in an optimum compressive strength of 46.38 MPa after being cured for 28 days, and the SEM and FTIR analyses confirmed the denser surface of the geopolymer matrix. The synchrotron micro-XRF analyses confirmed that the Ca concentration exceeded that of Si and Mg, leading to the formation of calcium silicate hydrate, which strengthens the resulting geopolymers.

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Synchrotron microanalytical methods in the study of trace and minor elements in apatite

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Rakovan J. , Luo Y. , Borkiewicz O.

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tom Vol. 39, iss. 1/2

31--40

EN

Synchrotron X-ray facilities have the capability for numerous microanalytical methods with spatial resolutions in the micron to submicron range and sensitivities as low as ppm to ppb. These capabilities are the result of a high X-ray brilliance (many orders of magnitude greater than standard tube and rotating anode sources); a continuous, or white, spectrum through the hard X-ray region; high degrees of X-ray columniation and polarization; and new developments in X-ray focusing methods. The high photon flux and pulsed nature of the source also allow for rapid data collection and high temporal resolution in certain experiments. Of particular interest to geoscientists are X-ray fluorescence microprobes which allow for numerous analytical techniques including X-ray fluorescence (XRF) analysis of trace element concentrations and distributions; X-ray absorption spectroscopy (XAS) for chemical speciation, structural and oxidation state information; X-ray diffraction (XRD) for phase identification; and fluorescence microtomography (CMT) for mapping the internal structure of porous or composite materials as well as elemental distributions (Newville et al. 1999; Sutton et al. 2002; Sutton et al. 2004). We have employed several synchrotron based microanalytical methods including XRF, microEXAFS (Extended X-ray Absorption Fine Structure), microXANES (X-ray Absorption Near Edge Structure) and CMT for the study of minor and trace elements in apatite (and other minerals). We have also been conducting time resolved X-ray diffraction to study nucleation of and phase transformations among precursor phases in the formation of apatite from solution at earth surface conditions. Summaries of these studies are given to exemplify the capabilities of synchrotron microanalytical techniques.

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Development of accelerator technology in Poland Impact of European CARE and EuCARD programs

81%

Romaniuk R. S.

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2008

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tom Vol. 54, No 3

239-251

EN

The development of accelerator technology in Poland is strictly combined with the cooperation with specialist accelerator centers of global character, where the relevant knowledge is generated, allowing to build big and modern machines. These are relatively costly undertakings of interdisciplinary character. Most of them are financed from the local resources. Only the biggest machines are financed commonly by many nations like: LHC in CERN, ILC in Fermi Lab, E-XFEL in DESY. A similar financing solution has to be implemented in Poland, where a scientific and political campaign is underway on behalf of building two big machines, a Polish Synchrotron in Kraków and a Polish FEL in Świerk. Around these two projects, there are realized a dozen or so smaller ones.

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EuCARD i CARE : rozwój techniki akceleratorowej w Polsce

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Romaniuk R.

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tom Vol. 49, nr 10

12-17

PL

Rozwój techniki akceleratorowej w Polsce jest ściśle powiązany ze współpracą ze specjalistycznymi ośrodkami dysponującymi akceleratorami na świecie. gdzie jest generowana odpowiednia wiedza pozwalająca na budowę dużych i nowoczesnych maszyn. Są to przedsięwzięcia relatywnie kosztowne o charakterze interdyscyplinarnym. Znaczna część z nich jest finansowana lokalnie. Tylko największe maszyny są finansowane wspólnie przez wiele państw jak LHC w Cernie. ILC w Fermilabie i E-XFEL w Desy. Podobnie musi być w Polsce, gdzie trwa obecnie kampania naukowa i polityczna na rzecz budowy dwóch dużych maszyn: Polskiego Synchrotronu w Krakowie oraz Polskiego lasera na swobodnych elektronach POLFEL w Świerku. Wokół tych dwóch bardzo dużych projektów naukowo-technicznych realizowanych jest kilkadziesiąt mniejszych.

EN

The development of accelerator technology in Poland is strictly combined with the cooperation with specialised accelerator centers of global character, where the relevant knowledge is generated, allowing to build big and modern machines. These are relatively costly undertakings of interdisciplinary character. Most of them are financed by the local resources. Only the biggest machines are financed commonly by many nations like: LHC in Cern, ILC in Fermi Lab, E-XFEL in Desy. A similar financing solution has to be implemented in Poland, where a scientific and political campaign is underway in behalf of building two big machines, a Polish Synchrotron in Kraków and a Polish FEL in Świerk. Around these two projects, there are realized a dozen or so smaller ones.