Hasil untuk "cond-mat.soft"

J. Steele

Alex T. Coyle, R. Spragg, P. Suraneni et al.

The formation factor obtained through electrical resistivity measurements is becoming a popular method to determine transport properties of concrete. Resistivity measurements are dependent on multiple factors, including degree of saturation, pore solution conductivity, and temperature. The Arrhenius equation is used to correct electrical resistivity for temperature effects using an activation energy of conduction (Ea-cond). This parameter has been measured on a wide variety of materials, including pore solutions, pastes, mortars, and concretes (with a variety of saturation states). The reported values of Ea-cond typically range from 9 to 39 kJ/mol. This article examines the factors affecting Ea-cond in order to select an appropriate temperature correction. In this study, Ea-cond was determined from data measured on various concrete mixtures used in transportation infrastructure applications as well as extracted and simulated pore solutions. The Ea-cond of pore solutions remains relatively constant (an average value of 13.9 ± 1.5 kJ/mol) for typical pore solutions and was slightly lower than the Ea-cond of saturated specimens (an average value of 15.8 kJ/mol). It was found that Ea-cond increases as the degree of saturation of the specimen is reduced. Drying increases the ionic concentration of the fluid in the pores; however, this does not explain the changes in Ea-cond. The effects of drying were determined to be primarily due to a change in the volume of the conductive fluid film in the concrete and in the connectivity of the fluid-filled pores. While it is better to directly measure the Ea-cond of a concrete mixture, this is not always feasible or practical. In such cases, for pore solutions, a value of 13.9 kJ/mol can be used, and for saturated concretes, a value of 15.8 kJ/mol can be used. For concretes with a varying degree of saturation, the Ea-cond can be estimated using the developed equation.

Kohei Sato, A. Oue, Marina Yoneya et al.

Adam L Owen, D. Wong, Michael M McKenna et al.

William H. Otto, J. Coburn, L. Brown et al.

C. Castagna, F. Impellizzeri, E. Cecchini et al.

J. Mcbride, D. Blow, Tyler J. Kirby et al.

Paul Hough, E. Ross, G. Howatson

Brianna Caldwell, D. Peters

P. Wong, A. Chaouachi, K. Chamari et al.

N. Hori, R. Newton, N. Kawamori et al.

Jonathan C. Gullett, M. Tillman, Gregory M. Gutierrez et al.

Bruce R Thompson, J. Douglass, M. Ellis et al.

I. Fatouros, A. Chatzinikolaou, Ioannis I. Douroudos et al.

E. Me

M. Brink, E. Nederhof, C. Visscher et al.

A. Sunde, Ø. Støren, Marius Bjerkaas et al.

A. Dellal, Dominique Keller, C. Carling et al.

Roux

D. Podolsky, E. Demler, K. Damle et al.

Motivated by recent scanning tuneling microscopy (STM) experiments on Bi 2 Sr 2 CaCu 2 O 8 + δ [J. E. Hoffman et al., Science 295, 466 (2002); C. Howald et al., cond-mat/0201546 (unpublished); J. E. Hoffman et al., Science 297, 1149 (2002): K. McElroy et al. (unpublished); C. Howald et al., cond-mat/0208442 (unpublished)], we study the effects of weak translational symmetry breaking on the quasiparticle spectrum of a d-wave superconductor. We develop a general formalism to discuss periodic charge order, as well as quasiparticle scattering off localized defects. We argue that the STM experiments in Bi 2 Sr 2 CaCu 2 O 8 + δ cannot be explained using a simple charge density wave order parameter, but are consistent with the presence of a periodic modulation in the electron hopping or pairing amplitude. We review the effects of randomness and pinning of the charge order and compare it to the impurity scattering of quasiparticles. We also discuss implications of weak translational symmetry breaking for angle resolved photoemission spectroscopy experiments.