A study for hypergolic vapor sensor development

In summary, the following tasks were completed within the scope of this work: (1) a portable Monomethylhydrazine analyzer was developed, designed, fabricated and tested. (2) A portable NO2 analyzer was developed, designed, fabricated and tested. (3) Sampling probes and accessories were designed and fabricated for this instrumentation. (4) Improvements and modifications were made to the model 7630 Ecolyzer in preparation for field testing. (5) Instrument calibration procedures and hydrazine handling techniques necessary to the successful application of this hardware were developed

Toxic level hypergolic vapor detection sensor development

Development of an electrochemical sensor technology capable of PPB level hypergolic vapor sensing is reported. A portable instrument capable of meeting the design goals is described

Fish and Zooplankton Distributions in a Seasonally Hypoxic Fjord

Hypoxia has been identified as a major threat to marine ecosystem health in the world’s coastal waters including Puget Sound. This study is evaluating the potential effects of hypoxia on fish and zooplankton distributions in Hood Canal, WA, using multifrequency acoustics and net sampling. Field surveys were conducted monthly from June to October in 2012 and 2013 to characterize pre-, during, and post-hypoxia nekton distributions at four sites along the Canal. Using the repeated samplings and high-resolution survey data, we are examining how seasonal and inter-annual difference in the timing and intensity of hypoxia affects distributions of predators (primarily Pacific herring and Pacific hake) and prey (primarily copepods and euphausiids). Depth of the zooplankton backscatter layer changed seasonally with hypoxia intensity. Toward late-summer, the daytime zooplankton layer was closer to the surface, increasing the vertical separation between zooplankton and fish. In spite of low oxygen levels in late-summer, fish remained in low-oxygen regions of Hood Canal. This suggests a decrease in energy flow toward higher trophic level during hypoxia

X-ray magneto-optics of lanthanide materials: principles and applications

Lanthanide metals are a particular class of magnetic materials in which the magnetic moments are carried mainly by the localized electrons of the 4f shell. They are frequently found in technically relevant systems, to achieve, e.g., high magnetic anisotropy. Magneto-optical methods in the x-ray range are well suited to study complex magnetic materials in an element-specific way. In this work, we report on recent progress on the quantitative determination of magneto-optical constants of several lanthanides in the soft x-ray region and we show some examples of applications of magneto-optics to hard-magnetic interfaces and exchange-coupled layered structures containing lanthanide elements.Comment: 7 pages, 6 figures, invited contribution to the Symposium "X-ray magneto-optics" of the Spring Meeting of the German Physical Society held in Regensburg, Germany, 8-12 March 2004. Revised version, minor change

Critical Susceptibility Exponent Measured from Fe/W(110) Bilayers

The critical phase transition in ferromagnetic ultrathin Fe/W(110) films has been studied using the magnetic ac susceptibility. A statistically objective, unconstrained fitting of the susceptibility is used to extract values for the critical exponent (gamma), the critical temperature Tc, the critical amplitude (chi_o) and the range of temperature that exhibits power-law behaviour. A fitting algorithm was used to simultaneously minimize the statistical variance of a power law fit to individual experimental measurements of chi(T). This avoids systematic errors and generates objective fitting results. An ensemble of 25 measurements on many different films are analyzed. Those which permit an extended fitting range in reduced temperature lower than approximately .00475 give an average value gamma=1.76+-0.01. Bilayer films give a weighted average value of gamma = 1.75+-0.02. These results are in agreement with the -dimensional Ising exponent gamma= 7/4. Measurements that do not exhibit power-law scaling as close to Tc (especially films of thickness 1.75ML) show a value of gamma higher than the Ising value. Several possibilities are considered to account for this behaviour.Comment: -Submitted to Phys. Rev. B -Revtex4 Format -6 postscript figure