Radioactivity in coral skeletons and marine sediments collected from the St. Martin’s Island of Bangladesh

Journal of Radioanalytical and Nuclear Chemistry - Although the coral island ‘St. Martin’s’ serves as the most attractive place for leisure and tourism, but no data on...     

Sulfonated poly(ether ether ketone)/manganese dioxide composite for the removal of low level radionuclide ions from aqueous solution

Various composite adsorbents based on sulfonated poly(ether ether ketone)/manganese dioxide were prepared for the removal of stable and radioactive ions from contaminated aqueous solution. Batch adsorption experiments revealed superior adsorption capacities of the composite using very low initial concentration of studied elements. Starting with 1000 µg L⁻¹ contaminated solution, the maximum equilibrium metal uptake capacity reached 2.0 mg g⁻¹ for Pb²⁺, 1.9 mg g⁻¹ for Cd²⁺, Cu²⁺ and Zn²⁺, and 3.7 mg g⁻¹ for Co²⁺. In addition, the distribution coefficient reached 11,600 mL g⁻¹ for ¹³⁷Cs and 70,000 mL g⁻¹ for ²¹⁰Pb.

     

A Privacy Scheme for Digital Images Based on Quantum Particles

International Journal of Theoretical Physics - Quantum processing inspired every field of science and technology. Quantum digital content privacy schemes usually employs photons to communicate a...     

Determination of Protolytic Constants by Trilinear Fluorescence Spectroscopy

Protolytic equilibria often have profound effects on chemical activity, since protolytic species usually behave quite differently. It is therefore important to characterize the protolytic properties of important chemicals. Here we present a new approach to study protolytic equilibria of fluorescent species that is extremely accurate and relies on minimum assumptions. We show that by measuring 2-dimensional excitation/emission scans of samples at different pH. the 3-dimensional experimental data set, I(lambda(ex), lambda(em), C(pH)), can be unambiguously decomposed into the spectral responses of the protolytic species present as well as their concentration. The approach is demonstrated on the protolytic equilibrium of fluorescein. Although the fluorescein monoanion cannot be obtained in pure form, the spectra and concentrations of both fluorescein species, as well as the protolytic constant, are determined with excellent accuracy. The proposed method is general and can be applied not only for studies of protolytic equilibria, but on any chemical equilibria and chemical reactions involving fluorescent species.     

A computer program for automated data evaluation to support in vitro higher-throughput screening for drug metabolism and pharmacokinetics attributes

With the advances in analytical techniques, higher-throughput screening for drug metabolism and pharmacokinetics (DMPK) attributes has become an integral part of drug discovery. However, as the number of compounds increases, the volume of data that needs to be processed and evaluated increases exponentially. As a result, a major challenge for the analytical chemist is how to quickly process the vast amount of data so as to keep up with the throughput of the screening assay. We have developed a customized computer program for automated evaluation of the liquid chromatography/tandem mass spectrometric (LC/MS/MS) data generated from the in vitro DMPK screening assays. This program performs automatic data processing and quality control. It identifies analytical anomalies, such as low internal standard intensity and poor reproducibility of replicates. All analytical anomalies for individual compounds are summarized into an 'E-Log' in a color-coded format for reviewing. With the use of this program and other supporting software, data processing and evaluation for up to 100 compounds are accomplished in several minutes.     

Quinquevalent tungsten as a reducing agent in potentiometric titrations

Qmnquevalcnt tungsten prepared by the electrolytic reduction of tungstate in ION HC1 is sufficiently stable when kept in strong acid solutions under COg to be used as an effective reducing agent in potcntiometric titrations. It can be accurately standardised with dichromate. The formal redox potentials of the $\text{W}{}^{\mathrm{+6}}\text{W}{}^{\mathrm{+5}}$ system as determined at different acidities indicate that quinquevalent tungsten is more reducing than the corresponding molybdenum compound.Quinquevalent tungsten can be applied successfully as a volumetric reagent in the potentiometric titration of ferric iron in 8-ioN HC1 or in a mixture of HCl and H3PO4 0.5.N each and of cupric copper in 8N HCl at 80° C. It can also be applied for the estimation of iodate, provided that the latter is used as the titrant.     

Upper limits on a stochastic background of gravitational waves

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.     

Preface

Preface

Preface     

Synthese und Röntgenstrukturanalyse des Additionsproduktes von Schwefeltrioxid an Tetraschwefeltetranitrid (S4N4· SO3)

Synthesis and X-ray Structure Analysis of the Addition Compound of Sulfurtrioxide and Tetrasulfurtetranitride (S₄N₄· SO₃) S₄N₄ · SO₃ was obtained by reaction of S₄N₄ with SO₃ in CH₂Cl₂ and by solvent free reaction of S₄N₄ with Fluorosulfonic acid anhydride. The structure of the adduct could be determined by single crystal X-ray structure analysis. The “cage” of the S₄N₄ is analogous to the structure of S₄N₄ · SbCl₅ reconvoluted into a deformated saddle conformation with nearly C_s-symmetry. The S? N bond lengths in the S₄N₄ ring vary from 1.51 to 1.69 Å. The C_s-symmetry is significantly disturbed by the position of the SO₃ group. In the crystal structure with monoclinic unit cell of space group P2₁/n the molecules are packed into columns, which are arranged pseudohexagonally.     

Ultrasonic characterization of ceramic fibres at ambient and elevated temperatures

A non-destructive laser-generated ultrasonic inspection system has been developed to evaluate the elastic properties of ceramic fibres. The approach uses a pulsed Nd:YAG laser to excite ultrasonic signals in fibres. The signal is detected by a piezoelectric acoustic emission transducer to obtain the appropriate frequency response suitable for an elastically one-dimensional sample. By using a differential time-of-flight system, a very accurate measure of the velocity can be obtained in the fibre, with a total scatter of less than 0.5%. This approach has been used to investigate the Young's modulus of polycrystalline carbon and boron fibres as a function of stress. Both types of fibres were found to have a Young's modulus increase as greater applied loads were imposed. The carbon and boron fibres, along with silicon carbide fibres, were evaluated at elevated temperatures up to 700 °C. The carbon fibres were found to have an immediate decrease in the Young's modulus as the temperature was increased, due to oxidation of the carbon. The Young's modulus of the boron fibres decreased only at temperatures higher than 200 °C, probably the result of a microstructural transformation or relaxation. The silicon carbide fibres were found to have no significant change in the elastic properties up to 700 °C. The ultrasonic technique was also applied to polycrystalline alumina fibres and fibre tows between ambient temperature and 1200 °C in a specially designed furnace. Using this technique, it was possible to distinguish the changes in the elasticity of the alumina fibres as they were processed into -alumina. The change in the Young's modulus was readily apparent during phase transformations to -alumina. In addition, the ultrasonic velocity can be used to infer information concerning any coatings that were applied to the alumina fibres. This can be used to aid in the quantification of the coating thickness and uniformity. The application of the ultrasonic inspection system has demonstrated the ability to determine rapidly and non-destructively the elastic properties in ceramic fibres. The information gained from the measurements can be used as a quality assurance technique, or can be modified to be a real-time process control/process monitoring system.