Combustion synthesis of ceramic and metal-matrix composites

Combustion synthesis or self-propagating high temperature synthesis (SHS) is effected by heating a reactant mixture, to above the ignition temperature (Tig) whereupon an exothermic reaction is initiated which produces a maximum or combustion temperature, Tc. These SHS reactions are being used to produce ceramics, intermetallics, and composite materials. One of the major limitations of this process is that relatively high levels of porosity, e.g., 50 percent, remain in the product. Conducting these SHS reactions under adiabatic conditions, the maximum temperature is the adiabatic temperature, Tad, and delta H (Tad) = 0, Tad = Tc. If the reactants or products go through a phase change, the latent heat of transformation needs to be taken into account

The Impact of Pre-Performance Anxiety on VO2Peak Values in Female Collegiate Soccer Players

Peak oxygen consumption (VO2peak) testing is commonly performed to assess endurance training effectiveness in athletes, including soccer players. However, how variables such as playing position, training type (off-vs. in-season), and performance anxiety levels affect maximal exercise capacity have not been determined. PURPOSE: The aim of this study was to determine the effect of positioning, training type, and pre-performance directional anxiety on VO2 max values in female soccer players. METHODS: Sixteen female collegiate soccer players completed two trials using a cycle ergometer. VO2peak was determined by the participant’s inability to continue pedaling and/or an established plateau in VO2 despite increasing workload. Prior to testing, a Competitive State Anxiety Inventory (CSAI-2) was completed to determine somatic anxiety, cognitive anxiety, and self-confidence. RESULTS: No significant differences were found between VO2peak and positioning, training type, and pre-performance directional anxiety (p=0.085, p=0.115, p=0. 244 respectively). However, a strong correlation was found between somatic and cognitive anxiety (r2= 0.736, p=0.079). CONCLUSION: VO2peak values were not affected by positioning type in female collegiate soccer players. High and low levels of anxiety did not predict maximal performance capabilities; however, somatic and cognitive anxiety positively interacted in determining performance. To better characterize performance anxiety in the future, research could examine cortisol levels prior to maximal performance

WHAT\u27S PUZZLING YOU ... IS THE NATURE OF VARIABLE ANNUITY PROSPECTUSES

Variable annuity prospectuses contain too much information, and the Author contends that usually the reader gives up using them to make buying decisions. This Article discusses the challenge of writing effective variable annuity prospectus disclosures that will drive more informed decision-making by unidentified consumers who span a diverse range relating to financial literacy. The Article also examines how a lack of uniformity in industry jargon hampers consumer comprehension. Communication within the financial industry has gravitated toward design-based disclosure rather than solution-based disclosure, adding further confusion. By utilizing literacy studies conducted by the Office of Investor Education and Advocacy and continued collaboration between the financial industry and its regulators, the financial industry can better understand the financial literacy of its intended audience and determine how to teach consumers what they need to know. The Author contends that while other industries have identified how to empower consumers with the working knowledge needed to make informed decisions, the financial industry has not done so. Plain English disclosures will help improve suitability and drive more informed decision-making. The Author recommends improving the Form N-4 (variable annuity registration statement). Additionally, the National Association of Insurance Commissioners and the Financial Industry Regulatory Authority find that sales agents benefit from completing both basic annuity training as well as each product issuer’s training. Further, the Author proposes that the use of technology will improve consumer decision-making. This technology includes interactive text and video interspersed prospectuses on handheld devices

WHAT\u27S PUZZLING YOU ... IS THE NATURE OF VARIABLE ANNUITY PROSPECTUSES

Variable annuity prospectuses contain too much information, and the Author contends that usually the reader gives up using them to make buying decisions. This Article discusses the challenge of writing effective variable annuity prospectus disclosures that will drive more informed decision-making by unidentified consumers who span a diverse range relating to financial literacy. The Article also examines how a lack of uniformity in industry jargon hampers consumer comprehension. Communication within the financial industry has gravitated toward design-based disclosure rather than solution-based disclosure, adding further confusion. By utilizing literacy studies conducted by the Office of Investor Education and Advocacy and continued collaboration between the financial industry and its regulators, the financial industry can better understand the financial literacy of its intended audience and determine how to teach consumers what they need to know. The Author contends that while other industries have identified how to empower consumers with the working knowledge needed to make informed decisions, the financial industry has not done so. Plain English disclosures will help improve suitability and drive more informed decision-making. The Author recommends improving the Form N-4 (variable annuity registration statement). Additionally, the National Association of Insurance Commissioners and the Financial Industry Regulatory Authority find that sales agents benefit from completing both basic annuity training as well as each product issuer’s training. Further, the Author proposes that the use of technology will improve consumer decision-making. This technology includes interactive text and video interspersed prospectuses on handheld devices

Linear and Nonlinear Spectroscopic Probing of Solute Interactions with Chemically Modified Silica Surfaces

Solar energy conversion through biology would provide a renewable and nonpolluting abundance of energy. The bacterium Halobacterium salinarum converts solar to electrical energy by virtue of a transmembrane protein, bacteriorhodopsin. This transmembrane protein pumps protons across a nonconducting bilayer upon irradiation with green light. The bacterium evolved to perform this function inefficiently. If we were able to understand this process to engineer this protein for efficiency, then inexpensive energy production could be achieved. There are tens of thousands of different types of halobacteria, giving the opportunity to study different efficiencies and relating these to the protein structures. Technology does not yet exist to perform such screening. The goal of this research is to generate new separation technology that can ultimately enable such screening. This involves creating a method for separating oriented and functional transmembrane proteins that remain in an electrically insulating lipid bilayer, with aqueous solutions on either side of the bilayer. A pH change across the lipid bilayer upon irradiation of a known concentration of proteins would probe function. Differences in proton pumping efficiency for different proteins variants would provide structure-function information for engineering the proteins. A schematic diagram from the original proposal is shown here. The idea is that (a) a lipid bilayer supported on a hydrophilic polymer film will make the bilayer fluid, and (b) applying an electric field will cause electrophoretic migration of the transmembrane proteins. We demonstrated this concept experimentally in a paper that was published just after this new grant period started (Lipid Bilayers on Polyacrylamide Brushes for Inclusion of Membrane Proteins, Emily A. Smith, Jason W. Coym, Scott M. Cowell, Victor J. Hruby, Henry I. Yamamura, Mary J. Wirth, Langmuir, 21, 9644-9650, 2005). The electrophoretic mobility was slow (10{sup -8} cm{sup 2}/Vs), and we project that a two order of magnitude increase would make this a practical tool. We are investigating two ways of improving electrophoretic mobility: better polymer supports, and a novel nanoporous medium that suspends the bilayer over free solution

Magnetotransport in the CeIrIn5{_5} system: The influence of antiferromagnetic fluctuations

We present an overview of magnetotransport measurements on the heavy-fermion superconductor CeIrIn$_5$. Sensitive measurements of the Hall effect and magnetoresistance (MR) are used to elucidate the low temperature phase diagram of this system. The normal-state magnetotransport is highly anomalous, and experimental signatures of a pseudogap-like precursor state to superconductivity as well as evidence for two distinct scattering times governing the Hall effect and the MR are observed. Our observations point out the influence of antiferromagnetic fluctuations on the magnetotransport in this class of materials. The implications of these findings, both in the context of unconventional superconductivity in heavy-fermion systems as well as in relation to the high temperature superconducting cuprates are discussed

Ab Initio Treatment of Collective Correlations and the Neutrinoless Double Beta Decay of 48^{48}Ca

Working with Hamiltonians from chiral effective field theory, we develop a novel framework for describing arbitrary deformed medium-mass nuclei by combining the in-medium similarity renormalization group with the generator coordinate method. The approach leverages the ability of the first method to capture dynamic correlations and the second to include collective correlations without violating symmetries. We use our scheme to compute the matrix element that governs the neutrinoless double beta decay of $^{48}$Ca to $^{48}$Ti, and find it to have the value $0.61$, near or below the predictions of most phenomenological methods. The result opens the door to ab initio calculations of the matrix elements for the decay of heavier nuclei such as $^{76}$Ge, $^{130}$Te, and $^{136}$Xe.Comment: 6 pages, 4 figures and 1 table. supplementary material included. version to be publishe