ASPECTS REGARDING ESCROW SERVICES IN ROMANIA, AS AN IMPORTANT PART OF E-COMMERCE ACTIVITY

E-commerce has appeared and developed along with the Internet. Online buyers and sellers can become fraud victims. Escrow Services reduce the number of fraud cases and guarantees online transactions. In Romania, those services are only just beginning to act, as the cyber fraud phenomenon is present in our country in the same rates as worldwide.escrow, e-commerce, cyber - fraud, escrow accounts, legislation, online auctions

Investigation of silica - PVA xerogel microstructure evolution during thermal treatment by SANS experiment

The purpose of the study was to investigate the appearance of certain microstructures developing in the SiO2/PVA nanocomposite xerogels at different temperatures by small-angle neutron scattering (SANS). The samples were prepared by the alcoxide route of the sol-gel method. The SANS measurements were performed over a q (scattering vector) range from 0.05 to 3.7 nm-1, providing structural information at length scales (2π/q) between approximately 1 and 100 nm. The measured small-angle scattering intensities of silica and silica/PVA samples aged at 60°C and heat-treated at different temperatures, are presented in log-log plots. It is shown that both the molecular mass of organic and the temperature of thermal treatment have strong influence on transition tendency from mass fractal toward surface fractal structures

Nouvelle méthode de désassemblage virtuel pour la génération de gammes

Revue critique des méthodes de désassemblage -- Le concept de cycle de vie d'un produit -- Contrainte environnementale et impact sur le désassemblage -- Diverses manières d'effectuer le désassemblage -- Le désassemblage sélectif -- Synthèse du mémoire -- Considérations générales concernant le processus de désassemblage -- Disassembly for assembly, maintainability and recyclability -- Reversible and irreversible operations in disassembly process -- New method for disassembly using the wave propagation concept -- Vers une nouvelle approche de désassemblage en utilisant la propagation de vagues -- Désassemblage par la propagation de vagues -- Présentation d'un nouvel algorithme de désassemblage sélectif -- Étapes de l'algorithme sélectif de désassemblage par vagues -- Parralélisme entre les deux approches -- Algorithmic selection of a disassembly sequence of a component by a wave propagation method

Influence de la composition des sols sur la spéciation et la toxicité du chrome, du cuivre et de l'arsenic dans des sols contaminés par du CCA

Arséniate de cuivre chromaté (CCA) -- Caractéristiques du sol -- Interactions du CCA avec le sol -- Méthodes d'évaluation de la forme chimique des métaux dans le sol -- Extraction séquentielle des métaux lourds -- Spéciation de l'arsenic -- Biodisponibilité -- Méthodes d'évaluation de la toxicité des métaux présents dans le sol -- Test standard avec le ver de terre Eisenia foetida -- Tests standard avec l'orge Hordeum vulgare -- Distribution et spéciation du chrome, du cuivre et de l'arsenic dans les sols contaminés par cu CCA : influence de la composition du sol -- Influence de la composition du sol et de la spéciation des métaux sur la toxicité des sols contaminés par du CCA

Équations analytiques explicites du mouvement d’une minifusée

Développement d’un modèle mathématique de mouvement complet en dynamique rationnelle reformulé dans le cas général, avec intégration explicite et application démonstrative et pédagogique à la minifusée conçue et réalisée par les étudiants de l’ENSICA : fusée à structure carbone monolithique, propulsée par moteur à poudre et aérodynamiquement stable

The scattering from generalized Cantor fractals

We consider a fractal with a variable fractal dimension, which is a generalization of the well known triadic Cantor set. In contrast with the usual Cantor set, the fractal dimension is controlled using a scaling factor, and can vary from zero to one in one dimension and from zero to three in three dimensions. The intensity profile of small-angle scattering from the generalized Cantor fractal in three dimensions is calculated. The system is generated by a set of iterative rules, each iteration corresponding to a certain fractal generation. Small-angle scattering is considered from monodispersive sets, which are randomly oriented and placed. The scattering intensities represent minima and maxima superimposed on a power law decay, with the exponent equal to the fractal dimension of the scatterer, but the minima and maxima are damped with increasing polydispersity of the fractal sets. It is shown that for a finite generation of the fractal, the exponent changes at sufficiently large wave vectors from the fractal dimension to four, the value given by the usual Porod law. It is shown that the number of particles of which the fractal is composed can be estimated from the value of the boundary between the fractal and Porod regions. The radius of gyration of the fractal is calculated analytically.Comment: 8 pages, 4 figures, accepted for publication in J. Appl. Crys

The role of the Fe/Mo cations ordering degree and oxygen non-stoichiometry on the formation of the crystalline and magnetic structure of Sr2FeMoO6‒δ

Single-phase Sr2FeMoO6-δ powders with various oxygen indices (δ) and degrees of the superstructural ordering (P) of the Fe/Mo cations were obtained from SrFeO2.52 and SrMoO4 reagents via solid-state synthesis. It has been established by means of the x-ray and neutron diffraction that, upon reducing the oxygen content and enhancing the superstructural ordering, the lengths of the Fe–O1 and Mo–O2 bonds in the crystal lattice increase, whereas the Fe–O2 and Mo–O1 bond lengths decrease. At the same time, the volume of the unit cell is reduced, which indicates an enhancement of the covalency degree of the bonds and stimulates a redistribution of the electron density, as well as an increase of the concentration of the spin-down charge carriers located in the conduction band on the Mo(t2g)↓ orbitals. This circumstance leads to an increase of the density of states at the Fermi level, accompanied by an amplification of the exchange interaction and elevation of the Curie temperature, which points to the leading role of the spin-polarized charge carriers at the Fermi level in the exchange interaction.publishe

Influence of the Structure on Magnetic Properties of Calcium-Phosphate Systems Doped with Iron and Vanadium Ions

The aim of this study was to prepare and characterize the glasses made of x(Fe$_{2}$O$_{3}$∙V$_{2}$O$_{5}$)∙(100 − x)[P$_{2}$O$_{5}$∙CaO] with x ranging of 0–50%. The contribution of Fe$_{2}$O$_{3}$ and V$_{2}$O$_{5}$ amount on the structure of P$_{2}$O$_{5}$·CaO matrix was investigated. The vitreous materials were characterized by XRD (X-ray diffraction analysis), EPR (Electron Paramagnetic Resonance) spectroscopy, and magnetic susceptibility measurements. A hyperfine structure typical for isolated V4+ ions was noticed to all spectra containing low amount of V$_{2}$O$_{5}$. The XRD spectra show the amorphous nature of samples, apart x = 50%. An overlap of the EPR spectrum of a broad line without the hyperfine structure characteristic of clustered ions was observed with increasing V2O5 content. The results of magnetic susceptibility measurements explain the antiferromagnetic or ferromagnetic interactions expressed between the iron and vanadium ions in the investigated glass