Aims of This Work

The aim of this work which enter in a research project on NDT, is to conceive a system of aid for interpretation and taking decisions, on imperfections in metallic fusion welds, we have studied and tested several segmentation techniques based on the two approaches ( contour and regions ). A quantitative analysis will be applied to extract some relatives geometricals parameters. To the sight of these characteristics, a first classification will be possible. 

The aim of this work is the development of pyrene determination in gasoline and contaminated soils. For this purpose we used room temperature phosphorescence (RTP) in micellar solutions of sodium dodecylsulphate (SDS). For pyrene extraction from contaminated soils hexane was used. Then exttacts earned in glass and dried. After that remains was dissolved in SDS solution in the presence of sodium sulphite as deoxygenation agent and thallium (I) nitrate as heavy atom . For pyrene RTP excitation 337 nm wavelength was used. To check the accuracy of the procedures proposed for pyrene determining by RTP, the pyrene concentrations in the same gasoline samples were also measured by GC-MS. 

The aim of this work is the determination of several nutritional parameters, such as Energetic Value, Protein, Fat, and Carbohydrates content, in commercially available yoghurt samples by using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FT-IR) spectrometry and a partial least square approach. 

The aim of this work is to analyse processes for determination and removal (or reducing) greenhouse gases (GHG NO, SO, and CO) from air and make the comparative study of GHG emission and with production of electricity. Among various analytical methods green analytical techniques were analysed and tested for GHC determination. 

The aim of this work is the optimization of distillation process using H SO for fluoride separation and potentiometric determination in anhydrite samples by means of chemometric tools. 

Brombenztiazo (BBT) is known to be one of the best reagents for extraction-photometric determination of cadmium(II). The reagent also fonus complexes with Co(II), Cu(II), Fe(II), Ni(II), Zn(II). The aim of this work was to develop a solid-phase reagent on the base of BBT immobilized on silica gel for sorption-spectroscopic and visual test determination of Cadmium, and also for soi ption-atomic-adsoi ption determination of total heavy metals contents in natural waters. 

The aim of this work was to study the influence of a second ligand, the concentration and nature of surfactants on flumequine-sensitized fluorescence of lanthanides and the usage of such a mixed-ligand complex for fluorimetric determination of flumequine in hen meat tissues. 

In recent times, the study of molecular non-rigidity has been characterized by new and important developments in both experimental and theoretical directions. From the theoretical point of view, the pioneer work of Longuet-Higgins initiated numerous further studies The aim of this work was to extend the concept of symmetry to non-rigid molecules undergoing certain internal movements, the so-called feasible transformations. Some recent discussion of these problems may be found in Refs. for example. 

Aim of this work was to optimise enzymatic depolymerization of pectins to valuable oligomers using commercial mixtures of pectolytic enzymes. Results of experiments in continuous and batch reactor configurations are presented which give some preliminary indications helpful to process optimisation. The use of continuous reactors equipped with ultrafiltration membranes, which assure removal of the reaction products, allows to identify possible operation policy for the improvement of the reaction yield. 

The aim of this work is to obtain the four lowest E curves and wavefunctions of BH at the same level of accuracy and to bring out the interplay of ionic, Rydberg and valence states at energies and internuclear distances which were not previously investigated. We have therefore made use of a method, already put forward by us [16,17] to determine at once quasi-diabatic and adiabatic states, potential energy cnrves and approximate nonadiabatic couplings. We have analogously determined the first three E+ states, of which only the lowest had been theoretically studied... 

In this study butyl acetate (AcOBu) was hydrogenolysed to butanol over alumina supported Pt, Re, RePt and Re modified SnPt naphtha reforming catalysts both in a conventional autoclave and a high throughput (HT) slurry phase reactor system (AMTEC SPR 16). The oxide precursors of catalysts were characterized by Temperature-Programmed Reduction (TPR). The aim of this work was to study the role and efficiency of Sn and Re in the activation of the carbonyl group of esters. 

Chiral heterogeneous catalysts, although have lower enantioselectivity and stability than homogeneous catalysts, are often preferable because of their handling and separation properties (5). Aim of this work was to shed light on the enantioselective hydrogenation of a,p-unsaturated acids or their... 

The aim of this work was to find out how to get more information about stereochemistry and molecular motion of polymer methyl- and methyl-phenyl-siloxanes by measuring longitudinal relaxation times, Tj, and nuclear Overhauser effects, NOE, of the individual building blocks. 

The general aim of this work is to show the properties of activated carbon-ionic liquid interface (AC-IL) as well as performance of capacitors based on activated carbons as electrode materials and ionic liquids as electrolytes. 

Chromium zeolites are recognised to possess, at least at the laboratory scale, notable catalytic properties like in ethylene polymerization, oxidation of hydrocarbons, cracking of cumene, disproportionation of n-heptane, and thermolysis of H20 [ 1 ]. Several factors may have an effect on the catalytic activity of the chromium catalysts, such as the oxidation state, the structure (amorphous or crystalline, mono/di-chromate or polychromates, oxides, etc.) and the interaction of the chromium species with the support which depends essentially on the catalysts preparation method. They are ruled principally by several parameters such as the metal loading, the support characteristics, and the nature of the post-treatment (calcination, reduction, etc.). The nature of metal precursor is a parameter which can affect the predominance of chromium species in zeolite. In the case of solid-state exchange, the exchange process initially takes place at the solid- solid interface between the precursor salt and zeolite grains, and the success of the exchange depends on the type of interactions developed [2]. The aim of this work is to study the effect of the chromium precursor on the physicochemical properties of chromium loaded ZSM-5 catalysts and their catalytic performance in ethylene ammoxidation to acetonitrile. 

The aim of this work is to compare the thermal and catalytic cracking under representative conditions. To make things easier, the zeolites are used as powder in the catalytic test. 

The aim of this work was to apply combined temperature-programmed reduction (TPR)/x-ray absorption fine-structure (XAFS) spectroscopy to provide clear evidence regarding the manner in which common promoters (e.g., Cu and alkali, like K) operate during the activation of iron-based Fischer-Tropsch synthesis catalysts. In addition, it was of interest to compare results obtained by EXAFS with earlier ones obtained by Mossbauer spectroscopy to shed light on the possible types of iron carbides formed. To that end, model spectra were generated based on the existing crystallography literature for four carbide compounds of... 

Based on these observations and several other experimental results with cofeeding of ethene and 1-alkene,9 the selectivity of branched hydrocarbons,11 and the different promoter effects of Li-, Na-, K-, and Cs-carbonate/oxide,1213 a novel mechanism has been proposed that is consistent with these various experimental results.14 The formulation of this mechanism follows the knowledge of analogous reactions in homogeneous catalysis and gives a detailed insight in the crucial step of C-C linkage formation. The aim of this work is to discuss in detail these experiments and their relationship to the proposed mechanism. 

The first aim of this work was to study the influence of an unwashed membrane filter on the cadmium, lead, and copper concentrations of filtered seawater samples. It was also desirable to ascertain whether, after passage of a reasonable quantity of water, the filter itself could be assumed to be clean so that subsequent portions of filtrate would be uncontaminated. If this were the case, it should be possible to eliminate the cleaning procedure and its contamination risks. The second purpose of the work was to test the possibility of long-term storage of samples at their natural pH (about 8) at 4 °C, kept in low-density polyethylene containers which have been cleaned with acid and conditioned with seawater. 

The main aim of this work is to make an attempt to analyze all the aspects of nitrone chemistry and its application which have been developed over the last 15 years. The early works will also be considered to make comparisons, or if these works were not covered in previous reviews but if, as we see it, without mentioning these works, the representation of the diverse chemistry of nitrones seems incomplete. 

The aim of this work was to investigate the arsenic mobilization from the tailings material (200 - 500 pg/g As) into the seepage water (up to 3.5 mg/L As) and the process of seepage water effluent forming an immobilized precipitate (up to 8 % As) in the creek. Different analytical methods for the determination of total concentrations and different sequential extraction methods as well as hyphenated techniques for speciation analysis were applied to follow the way of the arsenic in this environment. 

However, some problems remain unsolved. The three- and four-body results of Choh and Uhlenbeck and of Cohen, respectively, have to be compared with the corresponding expressions in the Prigogine s theory. Furthermore, for any concentration, one has to see how the systematic generalization of the Boltzmann equation derived by Cohen is related to the long-time evolution equation in Prigogine s theory. The aim of this work is to throw some light on these points. 

An EPR and ENDOR investigation of the planar copper complex 63Cu(sal)2 (Fig. 30) substituted into a single crystal of Ni(sal)2 has been reported by Schweiger et al.62,65). The aim of this work was to determine the structure of the internal H-bond occuring in Cu(sal)2, and to draw a detailed picture of the unpaired electron distribution on the... 

The proton ENDOR study of the chromyl ethyleneglycolate anion in ethanol reported by Mohl et al.293 presents the first successful adaptation of the ENDOR technique to a transition metal complex in liquid solutions. The aim of this work was to characterize the ENDOR relaxation behavior and to find optimum conditions for ENDOR detection. Two proton ENDOR lines with a hf splitting of ajj, = 1.74 MHz were observed. This is in agreement with a previous EPR study294 which had shown that all eight protons are equivalent. The optimum microwave and rf fields are both proportional to (Tr(g - geO rAj 2)1/2, where A denotes the dipolar part of the proton hfs tensor. For the chromyl ethyleneglycolate anion these two values have been calculated to — 8 10-6T and B = 2.7 mT. According to Mohl et al.293, successful proton... 

Despite the undeniable synthetic value of the benzannulation reaction of aryl and alkenyl Fischer carbene complexes, the details of its mechanism at the molecular level remain to be ascertained. Indeed, although a relatively large number of theoretical studies have been directed to the study of the molecular and electronic structure of Fischer carbene complexes [22], few studies have been devoted to the analysis of the reaction mechanisms of processes involving this kind of complexes [23-30]. The aim of this work is to present a summary of our theoretical research on the reaction mechanism of the Dotz reaction between ethyne and vinyl-substituted hydroxycarbene species to yield p-hydroxyphenol. 

Abstract The aim of this work was to study the simultaneous effect of amount of clay, activation temperature, contact time, pH, and size of the adsorbent on the retention of oil-grease thermally activated illite by adsorption. The values obtained for the percentage of oil-grease removed ranged from 93.87% for 110°C up to 66.73% for 900°C. The adsorption experiment showed surface that the stronger heat treatment the most effective adsorption of oil-grease. 

The aim of this work, to develop a RP-HPLC method for the detemtination of four components given above in a new symp preparation by optimizing the experimental conditions using two level fractional factorial design. 

The aim of this work was to evaluate the inhibition effect of ome Allium aqueous extracts on acrosin and trypsin activities, a new aspect in the wide spectrum of Allium compound activities. The antioxidant capacity, probably responsible for antithrombosis and antitumoral effects, was determined for different parts of Allium plants (bulb, green leaf, white stalk). The toxicity of crude extracts was also determined. 

Experiments were conducted in our laboratory to evaluate many of the dynamical expectations for rapid laser heating of metals. One of the aims of this work was to identify those population distributions which were characteristic of thermally activated desorption processes as opposed to desorption processes which were driven by nontbennal energy sources. Visible and near-infrared laser pulses of nominally 10 ns duration were used to heat the substrate in a nonspecific fashion. Initial experiments were performed by Burgess etal. for the laser-induced desorption of NO from Pt(foil). Operating with a chamber base pressure 2 x 10 torr and with the sample at 200 K, initial irradiation of a freshly cleaned and dosed sample resulted in a short time transient (i.e. heightened desorption yield) followed by nearly steady state LID signals. The desorption yields slowly decreased with time due to depletion of the adsorbate layer at the rate of ca. 10 monolayer... 

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