Dating fired-clay ceramics using long-term power law rehydroxylation kinetics

Wilson, Moira; Carter, Margaret A.; Hall, Christopher; Hoff, W D; Ince, Ceren; Savage, Shaun D.; Mckay, Bernard; Betts, Ian

doi:10.1098/rspa.2009.0117

Cited by 84 publications

(173 citation statements)

References 27 publications

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“…Wilson et al (2003) showed evidence that moisture expansion in fired-clay bricks and the associated mass gain increases as the fourth root of the time since firing (the RHX power-law model). Further reports (Savage et al 2008a,b;Wilson et al 2009) have confirmed this power-law model, and in the case of moisture expansion over periods of more than 50 years (Hall et al 2011). Thus, the RHX rate equation is given as y = a(T )t 1/4 , (2.1)…”

Section: Rehydroxylation and The Rhx Kinetic Modelmentioning

confidence: 83%

“…In an earlier paper (Wilson et al 2009), we set out the principles of rehydroxylation (RHX) measurements on fired-clay bricks and tiles, and we noted that this method of dating should be applicable to archaeological pottery. Here we present the first results of applying RHX dating to three types of archaeological pottery, varying in age, type and depositional environment.…”

Section: Introductionmentioning

confidence: 99%

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Rehydroxylation (RHX) dating of archaeological pottery

et al. 2012

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We show that the rehydroxylation (RHX) method can be used to date archaeological pottery, and give the first RHX dates for three disparate items of excavated material. These are in agreement with independently assigned dates. We define precisely the mass components of the ceramic material before, during and after dehydroxylation. These include the masses of three types of water present in the sample: capillary water, weakly chemisorbed molecular water and chemically combined RHX water. We describe the main steps of the RHX dating process: sample preparation, drying, conditioning, reheating and measurement of RHX mass gain. We propose a statistical criterion for isolating the RHX component of the measured mass gain data after reheating and demonstrate how to calculate the RHX age. An effective lifetime temperature (ELT) is defined, and we show how this is related to the temperature history of a sample. The ELT is used to adjust the RHX rate constant obtained at the measurement temperature to the effective lifetime value used in the RHX age calculation. Our results suggest that RHX has the potential to be a reliable and technically straightforward method of dating archaeological pottery, thus filling a long-standing gap in dating methods.

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Section: Rehydroxylation and The Rhx Kinetic Modelmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Rehydroxylation (RHX) dating of archaeological pottery

et al. 2012

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“…In this way not only was a master function defining strict least upper bounds on T c established (11) (14). Percolative rehydroxylation is characteristic of ceramics and can be used to date them (15).…”

Section: Percolation | Theorymentioning

confidence: 99%

Percolative theories of strongly disordered ceramic high-temperature superconductors

Phillips

2010

Proc. Natl. Acad. Sci. U.S.A.

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Optimally doped ceramic superconductors (cuprates, pnictides, etc.) exhibit transition temperatures T c much larger than strongly coupled metallic superconductors like Pb (T c ¼ 7.2 K, E g ∕kT c ¼ 4.5) and exhibit many universal features that appear to contradict the Bardeen, Cooper, and Schrieffer theory of superconductivity based on attractive electron-phonon pairing interactions. These complex materials are strongly disordered and contain several competing nanophases that cannot be described effectively by parameterized Hamiltonian models, yet their phase diagrams also exhibit many universal features in both the normal and superconductive states. Here we review the rapidly growing body of experimental results that suggest that these anomalously universal features are the result of marginal stabilities of the ceramic electronic and lattice structures. These dual marginal stabilities favor both electronic percolation of a dopant network and rigidity percolation of the deformed lattice network. This "double percolation" model has previously explained many features of the normal-state transport properties of these materials and is the only theory that has successfully predicted strict lowest upper bounds for T c in the cuprate and pnictide families. Here it is extended to include Coulomb correlations and percolative band narrowing, as well as an angular energy gap equation, which rationalizes angularly averaged gap∕T c ratios, and shows that these are similar to those of conventional strongly coupled superconductors. percolation | theoryA ll known microscopic theories of metallic superconductors are based on the isotropic Bardeen, Cooper, and Schrieffer (BCS) model of Cooper pairs formed by attractive electronphonon interactions that overwhelm repulsive Coulomb interactions, yet many features of electron-phonon interactions in the BCS theory that are confirmed in metals appear to be weak or absent in the infrared spectra of ceramic layered high temperature superconductors (HTSC) (1). The ceramics often exhibit multiple phases and must be doped to be not only superconductive but even metallic. By contrast layered undoped MgB 2 with T c ∼ 40 K is an "ideal" example of a metallic BCS crystalline superconductor where T c can be calculated quite accurately (2). When MgB 2 is substitutionally doped with ∼10% Al (on the Mg sites) or C (on the B sites), T c decreases drastically to ∼10 K (3). Many authors have invoked residual spin interactions in the doped state, left over from the magnetic undoped states, as a source of this difference (1). However, it has been known for a long time that electron-spin interactions (for instance, with magnetic impurities) drastically suppress T c by breaking S ¼ 0 Cooper pairs (4), and more generally that the insulating antiferromagnetic (AF) and metallic Cooper pair four-particle plaquette channels are completely independent (5). While ceramics often exhibit multiple phases, recently the data have shifted overwhelmingly in favor of phonon exchange as the only attractive interaction cor...

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“…Drying is an unavoidable preconditioning procedure for gas permeability [11,16], gas adsorption [17], gas diffusion [18] and water absorption [19,20]. However, despite the existence of numerous drying methods for PC samples [21][22][23], no drying methods have specifically been developed for AASC to date.…”

Section: Introductionmentioning

confidence: 99%

Establishment of a preconditioning regime for air permeability and sorptivity of alkali-activated slag concrete

Yang

Chen

Magee

et al. 2016

Cement and Concrete Composites

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This study reports an experimental investigation designed to assess the influence of near-surface moisture contents on permeation properties of alkali-activated slag concrete (AASC). Five different drying periods (5, 10, 15, 20 and 25 days) and three AASC and normal concretes with compressive strength grades ranging from C30 to C60 were considered. Assessment of moisture distribution was achieved using 100 mm diameter cores with drilled cavities. Results indicate that air permeability of AASC is very sensitive to the moisture content and its spatial distribution, especially at relative humidity above 65%. To control the influence of moisture on permeation testing, the recommendation of this paper is that AASC specimens should be dried in controlled conditions at 40 o C for 10 days prior to testing. It was also concluded from this study that AASC tends to perform less well, in terms of air permeability and sorptivity, than normal concrete for a given strength grade. This conclusion reinforces the need to further examine AASC properties prior to its widespread practical use.

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Dating fired-clay ceramics using long-term power law rehydroxylation kinetics

Cited by 84 publications

References 27 publications

Rehydroxylation (RHX) dating of archaeological pottery

Rehydroxylation (RHX) dating of archaeological pottery

Percolative theories of strongly disordered ceramic high-temperature superconductors

Establishment of a preconditioning regime for air permeability and sorptivity of alkali-activated slag concrete

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