Analysis of Petroleum Distillates from Fire Debris Using Supercritical Fluid Extraction with a Two‐Level Orthogonal Array Experimental Design

A supercritical fluid extraction (SFE) method was developed in the present study as an effective sample pretreatment technique of petroleum distillates from fire debris. Three petroleum distillates were used as target analytes, including 95 unleaded gasoline, kerosene, and premium diesel. An orthogonal array (L16) experimental design was adopted to separately evaluate primary SFE experimental factors. The SFE efficiencies of petroleum distillates at various extraction conditions were examined and the optimized SFE conditions were identified. Experimental results demonstrated that the optimized SFE method not only provided an effective extraction method for the spiked sample, but also successfully recovered residues of petroleum distillates from fire debris.     

Preliminary Investigation of the Effect of Select Pollutants on Marine Phytoplankton Using Multidimensional Fluorescence Measurements

Abstract

The use of multidimensional fluorescence for detecting the effects of select pollutants on algal fluorescence and production is demonstrated. Multidimensional fluorescence is ideally suited to rapidly measure algal fluorescence generated by both chlorophyll a and accessory pigments, as well as any changes induced by pollutants. Laboratory cultured and natural algae samples from classes Chlorophyceae, Bacillariophyceae, and Cyanophyceae were exposed to substituted nitroaromatics and fluorescence spectra of the algae recorded. Notable spectroscopic changes and fluorescence quenching were observed. In addition, a novel method for rapidly preconcentrating dilute natural marine samples is described.     

Birkhoff Coordinates for the Focusing NLS Equation

In this paper we construct Birkhoff coordinates for the focusing nonlinear Schrödinger equation near the zero solution.     

Symplectic Topology of Integrable Hamiltonian Systems, II: Topological Classification

The main purpose of this paper is to give a topological and symplectic classification of completely integrable Hamiltonian systems in terms of characteristic classes and other local and global invariants.     

Proper groupoids and momentum maps: Linearization, affinity, and convexity

We show that proper Lie groupoids are locally linearizable. As a consequence, the orbit space of a proper Lie groupoid is a smooth orbispace (a Hausdorff space which locally looks like the quotient of a vector space by a linear compact Lie group action). In the case of proper (quasi-)symplectic groupoids, the orbit space admits a natural integral affine structure, which makes it into an affine orbifold with locally convex polyhedral boundary, and the local structure near each boundary point is isomorphic to that of a Weyl chamber of a compact Lie group. We then apply these results to the study of momentum maps of Hamiltonian actions of proper (quasi-)symplectic groupoids, and show that these momentum maps preserve natural transverse affine structures with local convexity properties. Many convexity theorems in the literature can be recovered from this last statement and some elementary results about affine maps.     

Letter singularities of integrable and near-integrable hamiltonian systems

Summary The aim of this Letter is to show that the singularities of integrable Hamiltonian systems, besides being important for such systems themselves, also have many applications in the study of near-integrable systems. In particular, we will show how they are related to Kolmogorov’s nondegeneracy condition (in the famous KAM theorem), the Poincaré-Melnikov function and its generalizations, topological entropy, and nonintegrability criteria.     

Decomposition of nondegenerate singularities of integrable Hamiltonian systems

The main perpose of this letter is to give a topological classification of stable nondegenerate singularities of smooth integrable Hamiltonian systems. Namely, we show that all such singularities can be decomposed diffeomorphically, after a finite covering, to the direct product of simplest (codimension 1 and codimension 2 focus-focus) singularities.     

Design and characterization of a fiber optic-based fluorimeter

The design and preliminary charaterization of a novel fiber optic-based fluorimeter are reported. It includes a white light source, optical fibers for light transmission and an intensified photodiode array for detection. A bifurcated sensing configuration is used to transmit excitation and emission radiation to and from the analyte solution. Detection limits in the nanomolar range are reported for several test compounds.     

The adsorption properties of titanium dioxide

The adsorption properties of titanium dioxide were studied by gas chromatography. We used organic compounds from different classes, namely, n-alkanes, n-alkenes (C₆-C₈), and polar compounds (electron donors and acceptors) as test adsorbates. The differential heats of adsorption and the contributions of dispersion and specific intermolecular interaction energies were determined for the systems from the experimental retention data. The electron-donor and electron-acceptor characteristics of the ultimately hydroxylated surface of TiO₂ were evaluated.     

Galoisian obstructions to non-Hamiltonian integrability

We show that the main theorem of Morales, Ramis and Simo (2007) [6] about Galoisian obstructions to meromorphic integrability of Hamiltonian systems can be naturally extended to the non-Hamiltonian case. Namely, if a dynamical system is meromorphically integrable in the non-Hamiltonian sense, then the differential Galois groups of the variational equations (of any order) along its solutions must be virtually Abelian.