Measures and models for angular correlation and angular-linear correlation

Population models for dependence between two angular measurements and for dependence between an angular and a linear observation are proposed. The method of canonical correlations first leads to new population and sample measures of dependence in this latter situation. An example relating wind direction to the level of a pollutant is given. Next, applied to pairs of angular measurements, the method yields previously proposed sample measures in some special cases and a new sample measure in general

Induction probe determines levels of liquid metals

Mutual-inductance probe accurately measures liquid levels in a variety of liquid metals at elevated temperatures. It can be used in pyrochemical processes for the recovery of spent reactor fuel

A New Marine Ascomycete from Australia

Most marine pyrenomycetes are lignicolous, but some are epiphytic on marine phanerogims and algae. Meyers (1957) listed 30 species of algae known to be attacked by these fungi. A number of reports dealing with marine ascomycetes on algal hosts appeared before 1900, the most noteworthy being those of Winter (1887), and Jones (1898). Cotton (1908) described a pyrenomycete on Ascophyllum nodosum (L.) Le Jol. and summarized previous reports of ascomycetes found on algae. Reed (1902) collected two species, and Sutherland, in a series of papers (1914-1916), reported several alga-infesting pyrenomycetes. More recently, a number of ascomycetes occurring on algae have been noted (Feldmann, 1957, 1958; Cribb & Herbert, 1954; Cribb & Cribb, 1955, 1960a, b; Wilson & Knoyle, 1961; Kohlmeyer, 1963). This report describes a heretofore unreported pyrenomycete collected from the marine alga, Ballia callitricha Ag. The material was obtained from Warrnambool, Victoria, in waters off southern Australia

Moisture-resistant coatings for optical components

Plasma polymerization technique is used to apply thin, adherent, hydrophobic coatings from chlorotrifluoroethylene monomer. Apparently much of the chlorine contained in original monomer is lost during polymerization, and characteristic C-Cl absorption in infrared region is essentially absent

What is a quantum simulator?

Quantum simulators are devices that actively use quantum effects to answer questions about model systems and, through them, real systems. Here we expand on this definition by answering several fundamental questions about the nature and use of quantum simulators. Our answers address two important areas. First, the difference between an operation termed simulation and another termed computation. This distinction is related to the purpose of an operation, as well as our confidence in and expectation of its accuracy. Second, the threshold between quantum and classical simulations. Throughout, we provide a perspective on the achievements and directions of the field of quantum simulation.Comment: 13 pages, 2 figure

Average-Atom Model for X-ray Scattering from Warm Dense Matter

A scheme for analyzing Thomson scattering of x-rays by warm dense matter, based on the average-atom model, is developed. Emphasis is given to x-ray scattering by bound electrons. Contributions to the scattered x-ray spectrum from elastic scattering by electrons moving with the ions and from inelastic scattering by free and bound electrons are evaluated using parameters (chemical potential, average ionic charge, free electron density, bound and continuum wave functions, and occupation numbers) taken from the average-atom model. The resulting scheme provides a relatively simple diagnostic for use in connection with x-ray scattering measurements. Applications are given to dense hydrogen, beryllium, aluminum, titanium, and tin plasmas. At high momentum transfer, contributions from inelastic scattering by bound electrons are dominant features of the scattered x-ray spectrum for aluminum, titanium, and tin.Comment: 22 pages, 10 figures Presentation at Workshop IV: Computational Challenges in Warm Dense Matter at IPAM (UCLA) May 21 - 25, 201

Using the X-FEL to understand X-ray Thomson scattering for partially ionized plasmas

For the last decade numerous researchers have been trying to develop experimental techniques to use X-ray Thomson scattering as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such as those used in inertial confinement fusion. With the advent of the X-ray free electron laser (X-FEL) at the SLAC Linac Coherent Light Source (LCLS) we now have such a source available in the keV regime. One challenge with X-ray Thomson scattering experiments is understanding how to model the scattering for partially ionized plasmas. Most Thomson scattering codes used to model experimental data greatly simplify or neglect the contributions of the bound electrons to the scattered intensity. In this work we take the existing models of Thomson scattering that include elastic ion-ion scattering and the electron-electron plasmon scattering and add the contribution of the bound electrons in the partially ionized plasmas. Except for hydrogen plasmas almost every plasma that is studied today has bound electrons and it is important to understand their contribution to the Thomson scattering, especially as new X-ray sources such as the X-FEL will allow us to study much higher Z plasmas. Currently most experiments have looked at hydrogen or beryllium. We will first look at the bound electron contributions to beryllium by analysing existing experimental data. We then consider several higher Z materials such as Cr and predict the existence of additional peaks in the scattering spectrum that requires new computational tools to understand. For a Sn plasma we show that the bound contributions changes the shape of the scattered spectrum in a way that would change the plasma temperature and density inferred by the experiment.Comment: 13th International Conference on X-ray Lasers Paris, France June 10, 2012 through June 15, 201