Fundamental investigation of stress corrosion cracking

Two principle areas studied were stress corrosion crack growth rates of a titanium alloy in liquid environments containing halide ions and pitting corrosion of titanium in bromide solutions. Two initial assumptions were made, that the rate of propagation was controlled by a macroscopic solution parameter and that this parameter was viscosity. A series of solutions were prepared using lithium chloride as the solute and water, methanol, glycerin, formic acid, acetone, dimethyl sulphoxide, etc. As solvents, these solutions were prepared with a 5:1 solvent-solute ratio. Viscosity was varied by changing the temperature and it was found: (1) In all solvents the velocity of cracking was proportional to the reciprocal of the viscosity. (2) Each solvent gave a separate relationship, (3) The temperature dependence and numerical values for the apparent activation energy of cracking and viscosity were the same

Stress corrosion cracking of titanium alloys: Studies of cracks in thin specimens; SCC of Ti-6Al-4V in chloride, iodide and fluoride solutions; stress corrosion cracking in molten salts; electrochemistry of freshly generated titanium surfaces

Electrochemistry of freshly generated titanium surfaces and stress corrosion cracking in aqueous solutions and in molten salt

Shopping Center Saved by Short Aggregate Piers

We were faced with an extraordinary geotechnical challenge; our client wanted to support large tilt wa11 buildings and pavements for a 32 acre Commercial Shopping Center on 5 to 8 feet of saturated, I lo 3 blow/foot hydraulically placed fill. To make matters more difficult, the site was in the seismically active Napa Valley. We offered 3 solutions; 2 conventional, and 1 unconventional. Our conventional solutions consisted of: 1) piers founded in the normally consolidated clay below the hydraulic fill, or, 2) over-excavation and replacement of the upper 5 to 8 feet of highly unstable soil. Our unconventional solution consisted of Short Aggregate Piers (Geopier or SAP) to mitigate settlement for moderate building loads. Because of economics, speed and fear of the unknown over-excavation costs, our client chose Geopiers to support the large buildings

Impacts of Grazing on Watersheds: A State of Knowledge.

36 pgLivestock grazing affects watershed hydrologic properties by removing protective plant cover and by trampling. Reductions in the vegetation cover may: (a) increase the impact of raindrops, (b) decrease soil organic matter and soil aggregates, (c) increase surface crusts, (d) decrease infiltration rates, and/or increase erosion. Resultant impacts may include increased overland flow, reduced soil water content, and increased erosion. Bacteria and/or nutrients as potential pollutants from livestock grazing do not appear to be a problem on areas not included on riparian zones. Existing studies show no hydrologic advantage to grazing a watershed lightly rather than moderately. Some studies show no difference in soil loss, infiltration capacity, or soil bulk density between light. moderate, or ungrazed pastures. Little information supports claims for specialized grazing systems. To evaluate hydrologic impacts adequately, additional studies, both intensive and extensive, should be conducted

No Evidence for Orbital Loop Currents in Charge Ordered YBa2_2Cu3_3O6+x_{6+x} from Polarized Neutron Diffraction

It has been proposed that the pseudogap state of underdoped cuprate superconductors may be due to a transition to a phase which has circulating currents within each unit cell. Here, we use polarized neutron diffraction to search for the corresponding orbital moments in two samples of underdoped YBa$_2$Cu$_3$O$_{6+x}$ with doping levels $p=0.104$ and 0.123. In contrast to some other reports using polarized neutrons, but in agreement with nuclear magnetic resonance and muon spin rotation measurements, we find no evidence for the appearance of magnetic order below 300 K. Thus, our experiment suggests that such order is not an intrinsic property of high-quality cuprate superconductor single crystals. Our results provide an upper bound for a possible orbital loop moment which depends on the pattern of currents within the unit cell. For example, for the CC-$\theta_{II}$ pattern proposed by Varma, we find that the ordered moment per current loop is less than 0.013 $\mu_B$ for $p=0.104$.Comment: Comments in arXiv:1710.08173v1 fully addresse