Geology topics

M. A. Daley

Publications and source records attributed to M. A. Daley.

3 recordsLinked to original sources

USGS2017

Thin sectioning and surface replication of ice at low temperature.

We have developed a new technique for making thin sections and surface replicas of ice at temperatures well below 273 K. Cyanoacrylate glue forms a strong bond with ice and glass at 245 K, eliminating the need to fix the sample to the thin-section slide by melting and freezing. Surface replicas are made by melting away sample material once the glue has cured. Glue replicas are permanent and highly detailed, making them suitable for microstructural and textural studies at room temperature . Thin sections glued with cyanoacrylate glue are comparable in quality to melted-on sections. The ability to make thin sections without melting sample material is important in textural and microstructural studies of ice deformed at low temperatures because of annealing effects we have observed during conventional section making.

Journal of Glaciology↗

USGS1997

Adsorption of SO 2 onto oxidized and heat-treated activated carbon fibers (ACFs)

A series of activated carbon fibers (ACFs) and heat-treated oxidized ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore surface chemistry and pore volume for the adsorption of SO 2 and its catalytic conversion to H 2 SO 4 . For untreated ACFs, the initial rate of SO 2 adsorption from flue gas was shown to be inversely related to pore size. At longer times, the amount of SO 2 adsorbed from flue gas was dependent on both the pore size and pore volume. Oxidation of the ACFs, using an aqueous oxidant, decreased their adsorption capacity for SO 2 from flue gas due to a decrease in pore volume and repulsion of the SO 2 from acidic surface groups. If these samples were heat-treated to desorb the oxygen containing function groups, the amount of SO 2 adsorption increased. This increase in adsorption capacity was directly correlated to the amount of CO 2 evolved during heat-treatment of the oxidized ACFs. The amount of SO 2 adsorbed for these samples was related to the pore size, pore surface chemistry and pore volume. This analysis is explained in more detail in this paper.

Carbon↗

USGS1987

Inelastic properties of ice Ih at low temperatures and high pressures

The aim of our research programme is to explore the rheological behavior of H 2 O ices under conditions appropriate to the interiors of the icy satellites of the outer planets in order to give insight into their deformation. To this end, we have performed over 100 constant-strain-rate compression tests at pressures to 500 MPa and temperatures as low as 77 K. At P > 30 MPa, ice I h fails by a shear instability producing faults in the maximum shear stress orientation and failure strength typically is independent of pressure. This unusual faulting behavior is thought to be connected with phase transformations localized in the shear zones. The steady-state strength follows rheological laws of the thermally-activated power-law type, with different flow law parameters depending on the range of test temperatures. The flow laws will be discussed with reference to the operating deformation mechanisms as deduced from optical-scale microstructures and comparison with other work.

Journal de Physique Colloques↗