Application of ICP-MS radionuclide analysis to “Real World” samples of department of Energy radioactive waste

Germanium spectrometers must be operated at liquid nitrogen temperatures. Other detectors operate better when cooled. Many applications, because of hostile environments, inaccessibility, remote location, long duration, etc., are compromised, or totally precluded, by the requirement for liquid nitrogen. A Stirling cycle refrigerator based on a linear motor design, which is acoustically and vibrationally quiet, does not require secondary cooling, and operates unattended for years, is under development. System design and specifications are presented. Applications to cooled laser monitoring equipment. SQUID-based detection systems, environmental cleanup and monitoring, medical diagnostics, non-destructive testing systems, communication equipment, computer electronics, and imaging systems are discussed.     

Amide-water interactions in cosolvent systems. I. Solubilities and apparent molar volumes of methyl paraben

Solubility and apparent molar volume data are used to demonstrate effects of amide alkylation on amide-water interactions at 25° C. Precise measurements were made of the apparent molar volumes of the amides in binary amide-water mixtures using a dilatometric technique. The results show that the apparent molar volumes of alkyl-substituted amides in water pass through a minimum at an amide concentration which varies inversely with the degree of alkylation. Further studies showed that the solubilities of methyl paraben (methyl-p-hydroxybenzoate) and naphthalene in various amide-water solvent systems increased in characteristic fashion with amide alkylation.     

The Principal Element of a Frobenius Lie Algebra

We introduce the notion of the principal element of a Frobenius Lie algebra ${\frak{f}}$ . The principal element corresponds to a choice of ${F \in \frak{f}^{*}}$ such that F[–, –] non-degenerate. In many natural instances, the principal element is shown to be semisimple, and when associated to sl _n , its eigenvalues are integers and are independent of F. For certain “small” functionals F, a simple construction is given which readily yields the principal element. When applied to the first maximal parabolic subalgebra of sl _n , the principal element coincides with semisimple element of the principal three-dimensional subalgebra. We also show that Frobenius algebras are stable under deformation.     

Particle swarm optimization for the design and characterization of silica-based photonic crystal fiber amplifiers

In recent years, the development of photonic crystal fibers has allowed novel opportunities for enhancing optical amplifier characteristics. In this field, accurate numerical modeling is a significant need to predict the device behavior. Conventional approaches perform this task by using methods which could yield solutions characterized by divergent or unstably convergent algorithms. Global optimization methods can be considered as efficient tools to face this problem.In this paper, the application of particle swarm optimization to perform the design and characterization of photonic crystal fiber amplifiers is proposed. The employment of this technique shows different attractive features. In particular, solutions are found quickly and the implementation of the algorithm does not require complicated evolutionary operators. Numerical results show the effectiveness of the approach for both the design and characterization of a fiber amplifier. In fact, if considered as a design tool, the obtained numerical results are in good accordance with respect to the ones yielded by a conventional approach. If considered as a characterization tool, the algorithm performs a forecasting, allowing to determine parameters, such as homogeneous upconversion coefficients, whose computation could present difficulties when it is obtained via direct or indirect measurements.     

Rapid measurements of 235U fission product isotope ratios using an online,high-pressure ion chromatography inductively coupled plasma mass spectrometry protocol with comparison to isotopic depletion models

Journal of Radioanalytical and Nuclear Chemistry - An automated online separation–direct analysis method, RAPID (rapid analysis of post-irradiation debris), has been developed for the...     

Non-volatile organic analysis of uranium ore concentrates

In support of nuclear safeguards and non-proliferation efforts, Oak Ridge National Laboratory is responsible for characterizing uranium ore concentrate (UOC) samples obtained from two ore mining and milling sites. A sorptive extraction method has been developed for analysis of non-volatile organic compounds that might be used to identify characteristics of the purification process by which uranium was separated from these ores. This method utilizes Gerstel Twister^® stir bars coated with polydimethylsiloxane to extract organic components from aqueous media. A slurry of UOC is extracted with the Twister^® stir bar in 20 % methanol/80 % water containing deuterated internal hydrocarbon standards. Following extraction of non-volatile organics, the Twister^® stir bar is analyzed directly in the inlet of a gas chromatograph fitted with a quadrupole mass spectrometric detector. Results have been consistent and have shown excellent recoveries of internal standards, with the average recovery being 97.5 %. Both qualitative and quantitative differences have been identified between the two sources of UOC utilizing this method. One source contained an increased concentration of amines which commonly are used in the recovery and purification of ores. Amines that were identified in this UOC source include dioctylamine, triisoctylamine, and Alamine^® 336, a common industrial complexant. Also, when comparing both sources, the same UOC source contained various decanol and C20 compounds. Based on the results from this study, non-volatile organic analysis of UOC using sorptive extraction with Twister^® stir bars and GC–MS is a tool that can be used to facilitate sourcing of unknown UOC.     

Angular and axial evaluation of superficial defects on non-accessible pipes by wavelet transform and neural network-based classification

In this paper an effective procedure that allows evaluating the dimensions of corrosive flaws on non-accessible pipes is presented. The method is based on the propagation of ultrasound waves, analyzing the informative content of echoes reflected by defects. The approach exploits the properties of the wavelet transform to represent signals by a reduced form. The coefficients of this representation are selected properly by making use of a filter method followed by a genetic algorithm and, then, they feed a neural network classifier which evaluates the dimensions of defects on the pipe under test. Numerical results show low error rates in the evaluation of both angular and axial extension of each flaw. The main advantage offered by the method consists of analyzing long lines of non-accessible pipes, realizing an automatic evaluation of the dimensions of superficial flaws in pipelines.     

Inline gamma-spectrometry of fission product elements after rapid high-pressure ion chromatographic separation

Journal of Radioanalytical and Nuclear Chemistry - Analysis of irradiated material shortly after irradiation can be non-trivial due to highly radioactive activation and fission isotopes increasing...     

Presenting Schur Algebras as Quotients of the Universal Enveloping Algebra of gl2

We give a presentation of the Schur algebras S _Q (2,d) by generators and relations, in fact a presentation which is compatible with Serre's presentation of the universal enveloping algebra of a simple Lie algebra. In the process we find a new basis for S _Q (2,d), a truncated form of the usual PBW basis. We also locate the integral Schur algebra within the presented algebra as the analogue of Kostant's Z-form, and show that it has an integral basis which is a truncated version of Kostant's basis.     

On the cohomology of the Weyl algebra,the quantum plane,and the q-Weyl algebra

Deformation theory can be used to compute the cohomology of a deformed algebra with coefficients in itself from that of the original. Using the invariance of the Euler–Poincaré characteristic under deformation, it is applied here to compute the cohomology of the Weyl algebra, the algebra of the quantum plane, and the q-Weyl algebra. The behavior of the cohomology when q is a root of unity may encode some number theoretic information.