SYNTHESIS AND REACTIVITY OF 1,1-DI(ALKYLTHIO) ALKANES

Abstract

By interaction of mono- and dicarboil compounds with alkyl and arilmecaptances symmetric and and 1,1 - di(alkylthio) alkanes were synthesized. Reactions of these compounds with linear and cyclic scetals in the presence of mineral acids and cation- exchanged resins were studied. The main products are corresponding 1, alkylthioalkoxialkenes and 1,1-dialkoxialkanes. Kinetic investigations showed that the stage determiniung the process velocity is splitting of acetal group.     

The Preparation of 1H-Pyrazole-5-propanoic and 1H-Pyrazole-5-butanoic Acids from Dilithiated C(α),N-Carboalkoxyhydrazones and Succinic or Glutaric Acid Anhydrides

C(α),N-Carboalkoxyhydrazones were dilithiated with excess lithium diisopropylamide, condensed with succinic or glutaric acid anhydride, and cyclized to 1H-pyrazole-5-propanoic or 1H-pyrazole-5-butanoic acids.     

Holographic polymer materials with diffusion development: Principles, arrangement, investigation, and applications

We present a review of information that has been published in the scientific literature on the mechanism of formation (development, enhancement) of holograms at the expense of the photochemical attachment of phenanthrenequinone molecules and other compounds to polymer chains and diffusion mixing of unreacted molecules, on different types of light-sensitive materials that realize this mechanism, on the application of these materials to create volume holographic elements, on recording of information, and for research purposes.     

Fingerprint image enhancement using data driven Directional Filter Bank

A new method based upon data driven tool, principal component analysis (PCA), for fingerprint enhancement is proposed in this paper. PCA is a very useful statistical technique that has found application in many different fields like image compression, face recognition and is commonly used for finding patterns in data of high dimension. In the proposed method, the input image is first decomposed into directional images using decimation free Directional Filter Bank (DDFB). Then these directional images are normalized. A data driven technique PCA is applied to these normalized directional fingerprint images, which gives the PCA filtered images. These are basically directional images. Then these directional images are reconstructed into one image which is the enhanced one. Simulation results are included illustrating the capability of the proposed method.     

Radiological safety assessment inside ancient Egyptian tombs in Saqqara

Many archaeological sites in Egypt are unique worldwide, such as ancient tombs and pyramids, because they document fundamental developments in human civilization that took place several thousands of years ago. For this reason, these sites are visited by numerous visitors every year. The present work is devoted to provide a pre-operational radiological baseline needed to quantify occupational radiation exposure at the famous Saqqara region in Cairo, Egypt. A hyperpure Ge detector has been used in the γ-ray spectrometric analysis while the ²²²Rn concentration was measured using a portable radon monitor RTM 1688-2, SARAD. The mean specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K in the samples collected from the interior walls of the Saqqara tombs were determined and found to show average values of 16, 8.5 and 45 Bq kg^?1, respectively. The concentration of radon was measured inside the tombs Serapeum, South tomb and the Zoser Pyramid (fifth level) and an associated average working level of 0.83 WL was obtained. In order to avoid the health hazards associated with the exposure to radon during the long period of work inside these tombs, proposed solutions are introduced.     

The Ene-Reaction of Phosphaalkynes-Application for the Synthesis of Phosphiranes

Abstract

1,3-Butadienes 1 and 6-Methyl-2H-pyran-2-ones 6 react with two equivalents of phosphaalkynes 2 in a domino-reaction to the diphosphiranes 5 and 9 respectively. Diels-Alder-reaction of 1 with 2 leads to 3 which cannot be isolated. An Ene-reaction of the phosphacyclohexa-1,4-diene 3 with additional 2 gives 4 followed by an intramolecular Diels-Alder-reaction yielding the stable diphosphatricyclooctenes 5.     

Method for determining the tritium concentration using the effects of dissociation of molecular beams of hydrogen isotopes on thin carbon films

Physical foundations of a new method for mass-spectrometric determination of tritium concentration in hydrogen-containing media, which is based on the effect of dissociation of molecular ions of hydrogen isotopes passing through thin carbon films, are formulated. The effects accompanying the interaction of particles with a solid (angular scattering, change in the charge state, energy losses in protons, deuterons, and tritons) are analyzed. The corresponding theoretical and experimental data indicate that the proposed technology can be implemented in practice for a comparatively low particle energy of ∼10 keV/nucleus.