Complex Device for Water Analytic

Gutt, Gheorghe; Gutt, Sonia; Poroch-Seriţan, Maria; Gutt, Andrei

doi:10.2507/22nd.daaam.proceedings.338

Cited by 2 publications

(3 citation statements)

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“…The observation of orthophosphate (PO 4 ) 3− units in alite and belite by replacement of (SiO 4 ) 4− tetrahedra is in agreement with the commonly suggested substitution mechanism from studies of guest ions in pure phases of alite and belite. − In cases where phosphorus is considered as the only element of substitution, charge balance may be achieved by creation of Ca 2+ ion vacancies, ,, i.e., 2 false( SiO 4 false) 4 − + Ca 2 + → 2 false( PO 4 false) 3 − + normal◻ Ca These vacancies may explain that only a small amount of phosphate can be incorporated in pure Ca 3 SiO 5 , corresponding to a maximum P/Si ratio of 0.036 . However, in commercial cements a number of other guest ions are incorporated in the calcium silicate phases, Mg, Al, Fe, S, Na, K, and F being the most common elements .…”

Section: Resultsmentioning

confidence: 99%

“…Earlier studies have shown that phosphorus (P 5+ in (PO 4 ) 3− ions) mainly enters the calcium silicate phases with a preferential formation of a phosphatic belite solid solution for phosphorus concentrations above 1 wt % P 2 O 5 . , The upper limit for incorporation of phosphate ions in alite has been reported to be 1.1 wt % P 2 O 5 , corresponding to a molar P/Si ratio of 0.036. Furthermore, incremental addition of P 2 O 5 results in a progressive reduction in the alite content, corresponding to 9.9 wt % per added 1 wt % of P 2 O 5 , which significantly reduces the mechanical strength of the resulting hydrated Portland cement.…”

Section: Introductionmentioning

confidence: 99%

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Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from ³¹P MAS NMR Spectroscopy

Jakobsen

2010

Inorg. Chem.

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Portland cements may contain small quantities of phosphorus (typically below 0.5 wt % P(2)O(5)), originating from either the raw materials or alternative sources of fuel used to heat the cement kilns. This work reports the first (31)P MAS NMR study of anhydrous and hydrated Portland cements that focuses on the phase and site preferences of the (PO(4))(3-) guest ions in the main clinker phases and hydration products. The observed (31)P chemical shifts (10 to -2 ppm), the (31)P chemical shift anisotropy, and the resemblance of the lineshapes in the (31)P and (29)Si MAS NMR spectra strongly suggest that (PO(4))(3-) units are incorporated in the calcium silicate phases, alite (Ca(3)SiO(5)) and belite (Ca(2)SiO(4)), by substitution for (SiO(4))(4-) tetrahedra. This assignment is further supported by a determination of the spin-lattice relaxation times for (31)P in alite and belite, which exhibit the same ratio as observed for the corresponding (29)Si relaxation times. From simulations of the intensities, observed in inversion-recovery spectra for a white Portland cement, it is deduced that 1.3% and 2.1% of the Si sites in alite and belite, respectively, are replaced by phosphorus. Charge balance may potentially be achieved to some extent by a coupled substitution mechanism where Ca(2+) is replaced by Fe(3+) ions, which may account for the interaction of the (31)P spins with paramagnetic Fe(3+) ions as observed for the ordinary Portland cements. A minor fraction of phosphorus may also be present in the separate phase Ca(3)(PO(4))(2), as indicated by the observation of a narrow resonance at delta((31)P) = 3.0 ppm for two of the studied cements. (31)P{(1)H} CP/MAS NMR spectra following the hydration of a white Portland cement show that the resonances from the hydrous phosphate species fall in the same spectral range as observed for (PO(4))(3-) incorporated in alite. This similarity and the absence of a large (31)P chemical shift ansitropy indicate that the hydrous (PO(4))(3-) species are incorporated in the interlayers of the calcium-silicate-hydrate (C-S-H) phase, the principal phase formed upon hydration of alite and belite.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from ³¹P MAS NMR Spectroscopy

Jakobsen

2010

Inorg. Chem.

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“…The introduction of the non-Abelian * -product is reminiscent of the Moyal product in the Weyl quantization approach [48,49] to ordinary nonrelativistic quantum mechanics. Indeed, the study of field theories on noncommutative spacetimes is greatly simplified by the introduction of a Weyl map [50][51][52], which is nothing but the generalization to field theory of the linear map from the classical phase-space functions to functions of quantum operators, first used in Weyl quantization.…”

Section: Noncommutative Spacetimesmentioning

confidence: 99%

Fractional and noncommutative spacetimes

et al. 2011

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We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determining the log-period coincides with the non-rotation-invariant but cyclicity-preserving measure of κ-Minkowski. At scales larger than the log-period, the fractional measure is averaged and becomes a power-law with real exponent. This can be also regarded as the cyclicity-inducing measure in a noncommutative spacetime defined by a certain nonlinear algebra of the coordinates, which interpolates between κ-Minkowski and canonical spacetime. These results are based upon a braiding formula valid for any nonlinear algebra which can be mapped onto the Heisenberg algebra.

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Complex Device for Water Analytic

Cited by 2 publications

References 2 publications

Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from ³¹P MAS NMR Spectroscopy

Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from ³¹P MAS NMR Spectroscopy

Fractional and noncommutative spacetimes

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Complex Device for Water Analytic

Cited by 2 publications

References 2 publications

Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from 31P MAS NMR Spectroscopy

Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from 31P MAS NMR Spectroscopy

Fractional and noncommutative spacetimes

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Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from ³¹P MAS NMR Spectroscopy

Incorporation of Phosphorus Guest Ions in the Calcium Silicate Phases of Portland Cement from ³¹P MAS NMR Spectroscopy