20,964 research outputs found
Swarm optimization for adaptive phase measurements with low visibility
Adaptive feedback normally provides the greatest accuracy for optical phase
measurements. New advances in nitrogen vacancy centre technology have enabled
magnetometry via individual spin measurements, which are similar to optical
phase measurements but with low visibility. The adaptive measurements that
previously worked well with high-visibility optical interferometry break down
and give poor results for nitrogen vacancy centre measurements. We use advanced
search techniques based on swarm optimisation to design better adaptive
measurements that can provide improved measurement accuracy with low-visibility
interferometry, with applications in nitrogen vacancy centre magnetometry.Comment: 8 pages, 7 figures, comments welcom
Influence of gaseous hydrogen on metals Interim report
Gaseous hydrogen embrittlement in Inconel 718, Inconel 625, AISI 321 stainless steel, Ti-5Al-25Sn ELI, and OFHC coppe
Japanese Beef Policy and GATT Negotiations: An Analysis of Reducing Assistance to Beef Producers
International Development, Livestock Production/Industries,
When do children need kidney replacement therapy?
Kidney replacement therapy (KRT) can provide lifesaving support for children with severely impaired kidney function. The decision about who needs KRT and when is often complex. Many acute kidney problems will resolve with conservative maanagemenent but some children with chronic or acute kidney impairment will find themselves in a position where KRT is required either as a bridge to recovery or kidney transplantation. Less commonly, children with metabolic disorders may find that the ability of their own kidneys is overwhelmed by excessive production of certain metabolites. These children may also benefit from short term KRT. This article aims to help paediatricians in training understand which children need kidney replacement therapy, the various types of treatment available, and when they are used
Acoustic spectral analysis and testing techniques
Subjects covered in four reports are described including: (1) mathematical techniques for combining decibel levels of octaves or constant bandwidth: (2) techniques for determining equation for power spectral density function; (3) computer program to analyze acoustical test data; and (4) computer simulation of horn responses utilizing hyperbolic horn theory
Reconstruction of eolian bed forms and paleocurrents from cross-bedded strata at Victoria Crater, Meridiani Planum, Mars
Outcrop exposures imaged by the Opportunity rover at Victoria Crater, a 750 m diameter crater in Meridiani Planum, are used to delineate sedimentary structures and further develop a dune-interdune depositional model for the region. The stratigraphy at Victoria Crater, observed during Opportunity's partial traverse of its rim, includes the best examples of meter-scale eolian cross bedding observed on Mars to date. The Cape St. Mary promontory, located at the southern end of the rim traverse, is characterized by meter-scale sets of trough cross bedding, suggesting northward migrating sinuous-crested bed forms. Cape St. Vincent, which is located at the opposite end of the traverse, shows tabular-planar stratification indicative of climbing bed forms with meter- to decameter-scale dune heights migrating southward. Promontories located between Cape St. Mary and Cape St. Vincent contain superposed stratigraphic units with northward and southward dipping beds separated by outcrop-scale bounding surfaces. These bounding surfaces are interpreted to be either reactivation and/or superposition surfaces in a complex erg sea. Any depositional model used to explain the bedding must conform to reversing northward and southward paleomigration directions and include multiple scales of bed forms. In addition to stratified outcrop, a bright diagenetic band is observed to overprint bedding and to lie on an equipotential parallel to the preimpact surface. Meter-scale cross bedding at Victoria Crater is similar to terrestrial eolian deposits and is interpreted as a dry dune field, comparable to Jurassic age eolian deposits in the western United States
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