Electric-arc heater Patent

Magnetically diffused radial electric arc heate

A magnetically rotated electric arc air heater employing a strong magnetic field and copper electrodes

Magnetically rotated electric arc air heater using strong magnetic field and copper electrode

Spectroscopic study of unique line broadening and inversion in low-pressure microwave generated water plasmas

It was demonstrated that low pressure (~0.2 Torr) water vapor plasmas generated in a 10 mm inner diameter quartz tube with an Evenson microwave cavity show at least two features which are not explained by conventional plasma models. First, significant (> 0.25 nm) hydrogen Balmer_ line broadening, of constant width, up to 5 cm from the microwave coupler was recorded. Only hydrogen, and not oxygen, showed significant line broadening. This feature, observed previously in hydrogen-containing mixed gas plasmas generated with high voltage dc and rf discharges was explained by some researchers to result from acceleration of hydrogen ions near the cathode. This explanation cannot apply to the line broadening observed in the (electrodeless) microwave plasmas generated in this work, particularly at distances as great as 5 cm from the microwave coupler. Second, inversion of the line intensities of both the Lyman and Balmer series, again, at distances up to 5 cm from the coupler, were observed. The line inversion suggests the existence of a hitherto unknown source of pumping of the optical power in plasmas. Finally, it is notable that other aspects of the plasma including the OH* rotational temperature and low electron concentrations are quite typical of plasmas of this type.Comment: 27 pages, 7 figure

Small high-temperature nuclear reactors for space power

Criticality calculations for small, cylindrical, lithium cooled reactors for space power system

The structure of a far-red fluorescent protein, AQ143, shows evidence in support of reported red-shifting chromophore interactions

Engineering fluorescent proteins (FPs) to emit light at longer wavelengths is a significant focus in the development of the next generation of fluorescent biomarkers, as far-red light penetrates tissue with minimal absorption, allowing better imaging inside of biological hosts. Structure-guided design and directed evolution have led to the discovery of red FPs with significant bathochromic shifts to their emission. Here, we present the crystal structure of one of the most bathochromically shifted FPs reported to date, AQ143, a nine-point mutant of aeCP597, a chromoprotein from Actinia equina. The 2.19 Å resolution structure reveals several important chromophore interactions that contribute to the protein's far-red emission and shows dual occupancy of the green and red chromophores

Microfabricated Silicon Mixers for Submillisecond Quench-Flow Analysis

Elucidation of fast chemical reactions such as protein folding requires resolution on a submillisecond time scale. However, most quench-flow and stop-flow techniques only allow chemical processes to be studied after a few milliseconds have elapsed. In order to shorten the minimum observation time for quench-flow experiments, we designed a miniaturized mixer assembly. Two “T” mixers connected by a channel are etched into a 1 cm × 1 cm silicon chip which is interfaced with a commercially available quench-flow instrument. Decreasing the volume of the mixing chambers and the distance between them results in an instrument with greatly reduced dead times. As a test of submillisecond measurements, we studied the basic hydrolysis of phenyl chloroacetate. This reaction proceeds with a second-order rate constant, k = 430 M^(-1) s^(-1), and shows pseudo-first-order kinetics at high hydroxide concentrations. The chemical reaction data demonstrate that the silicon device is capable of initiating and quenching chemical reactions in time intervals as short as 110 μs. The performance of these mixers was further confirmed by visualization using acid-base indicators

Field theory of the inverse cascade in two-dimensional turbulence

A two-dimensional fluid, stirred at high wavenumbers and damped by both viscosity and linear friction, is modeled by a statistical field theory. The fluid's long-distance behavior is studied using renormalization-group (RG) methods, as begun by Forster, Nelson, and Stephen [Phys. Rev. A 16, 732 (1977)]. With friction, which dissipates energy at low wavenumbers, one expects a stationary inverse energy cascade for strong enough stirring. While such developed turbulence is beyond the quantitative reach of perturbation theory, a combination of exact and perturbative results suggests a coherent picture of the inverse cascade. The zero-friction fluctuation-dissipation theorem (FDT) is derived from a generalized time-reversal symmetry and implies zero anomalous dimension for the velocity even when friction is present. Thus the Kolmogorov scaling of the inverse cascade cannot be explained by any RG fixed point. The beta function for the dimensionless coupling ghat is computed through two loops; the ghat^3 term is positive, as already known, but the ghat^5 term is negative. An ideal cascade requires a linear beta function for large ghat, consistent with a Pad\'e approximant to the Borel transform. The conjecture that the Kolmogorov spectrum arises from an RG flow through large ghat is compatible with other results, but the accurate k^{-5/3} scaling is not explained and the Kolmogorov constant is not estimated. The lack of scale invariance should produce intermittency in high-order structure functions, as observed in some but not all numerical simulations of the inverse cascade. When analogous RG methods are applied to the one-dimensional Burgers equation using an FDT-preserving dimensional continuation, equipartition is obtained instead of a cascade--in agreement with simulations.Comment: 16 pages, 3 figures, REVTeX 4. Material added on energy flux, intermittency, and comparison with Burgers equatio

Measurement of Ada Throughout the Software Development Life Cycle

Quality enhancement has now become a major factor in software production. Software metrics have demonstrated their ability to predict source code complexity at design time and to predict maintainability of a software system from source code. Obviously metrics can assist software developers in the enhancement of quality. Tools which automatically generate metrics for Ada are increasing in popularity. This paper describes an existing tool which produces software metrics for Ada that may be used throughout the software development life cycle. This tool, while calculating established metrics, also calculates a new structure metric that is designed to capture communication interface complexity. Measuring designs written using Ada as a PDL allows designers early feedback on possible problem areas in addition to giving direction on testing strategies

A methodological proposal and tool support for the HL7 standards compliance in the development of health information systems

Health information systems are increasingly complex, and their development is presented as a challenge for software development companies offering quality, maintainable and interoperable products. HL7 (Health level 7) International, an international non-profit organization, defines and maintains standards related to health information systems. However, the modelling languages proposed by HL7 are far removed from standard languages and widely known by software engineers. In these lines, NDT is a software development methodology that has a support tool called NDT-Suite and is based, on the one hand, on the paradigm of model-driven engineering and, on the other hand, in UML that is a widely recognized standard language. This paper proposes an extension of the NDT methodology called MoDHE (Model Driven Health Engineering) to offer software engineers a methodology capable of modelling health information systems conforming to HL7 using UML domain models

Computational Design of the β-Sheet Surface of a Red Fluorescent Protein Allows Control of Protein Oligomerization

Computational design has been used with mixed success for the design of protein surfaces, with directed evolution heretofore providing better practical solutions than explicit design. Directed evolution, however, requires a tractable high-throughput screen because the random nature of mutation does not enrich for desired traits. Here we demonstrate the successful design of the β-sheet surface of a red fluorescent protein (RFP), enabling control over its oligomerization. To isolate the problem of surface design, we created a hybrid RFP from DsRed and mCherry with a stabilized protein core that allows for monomerization without loss of fluorescence. We designed an explicit library for which 93 of 96 (97%) of the protein variants are soluble, stably fluorescent, and monomeric. RFPs are heavily used in biology, but are natively tetrameric, and creating RFP monomers has proven extremely difficult. We show that surface design and core engineering are separate problems in RFP development and that the next generation of RFP markers will depend on improved methods for core design