Ionic relaxation in nematic liquid crystal cells

We investigate the dependence of the relaxation time of the current flowing in a nematic cell submitted to an external dc voltage on the physical properties of the substrate. We show that previously presented analyses of the same problem are not very useful for practical applications. We compare our theoretical predictions with experimental data, and show that the agreement is rather good. The influence of the adsorption-desorption phenomenon on the relaxation time is also discussed.     

Study of the reciprocal space image of the biaxial nematic phase in the plane of the amphiphilic bilayer

High resolution synchrotron X-ray measurements have been performed on the uniaxial and biaxial phases of the lyotropic mixture potassuim laurate, decanol and water. An elegant magnetic orientational procedure allows us to obtain the cut of the reciprocal space image of the biaxial phase at the plane perpendicular to the amphiphilic bilayer. The analysis of densitometric profiles of the diffracted bands indicate an anisotropic micellar correlation in the plane of the amphiphilic bilayer. It is suggested that an anisotropic distribution of decanol and potassium laurate in this plane could be responsible for this effect.     

Evidence of shear-dependent boundary slip in newtonian liquids

The European Physical Journal E - The flow of Newtonian fluids was studied by directly measuring the hydrodynamic drainage force acting on a sphere approaching a flat surface. Our force...     

Reductive sulfur extrusion reaction of 2,1,3-benzothiadiazole compounds: a new methodology using NaBH4/CoCl2·6H2O(cat) as the reducing system

A new simple and efficient methodology for reductive sulfur extrusion from 2,1,3-benzothiadiazole compounds has been developed using NaBH₄ in the presence of catalytic amounts of CoCl₂·6H₂O (1 mol %). This method is an efficient alternative for the generation of various 1,4-disubstituted-2,3-diaminobenzene derivatives from 4,7-disubstituted-2,1,3-benzothiadiazoles. The diamines can be easily converted into 4,7-disubstituted-quinoxaline compounds by simple reaction with glyoxal-sodium bisulfite.     

Zum Nachweis der Oxyde von Molybdän,Wolfram und Vanadin

Zusammenfassung Es wird eine sehr empfindliche Reaktion zum Nachweis der Oxyde des Molybdäns, Wolframs und Vanadins angegeben. Sie beruht auf der Abscheidung von braunem Thallium(III)-oxydhydrat, aus ammoniakalischer Lösung von Thallium(I)-salzen auf Zusatz von Wasserstoffsuperoxyd und den oben genannten Oxyden, die hiebei als Katalysatoren wirken.Herrn Prof. Dr.Emil Abel, dem österreichischen Altmeister der Katalysenforschung, zum 80. Geburtstag.     

Improvement in steroid screening for doping control with special emphasis on stanozolol

The Medical Commission of the International Olympic Committee forbids the use of anabolic androgenic steroids and beta2-agonists to improve athletic performance. In this work we have selected examples of anabolic androgenic compounds and their metabolites to evaluate the GC-MS analysis of some trimethylsilyl derivatives. The aim is to set the best GC conditions to improve the detection within the whole range of analyte elution temperatures. The initial column temperature was changed to 105 or 140 degrees C followed by 40 degrees C min(-1) to 200 degrees C and then 15 degrees C min(-1) to 300 degrees C. Using 140 degrees C as the initial oven temperature it was possible to obtain narrower initial analyte distributions for the compounds that elutes at the beginning of the chromatogram as clenbuterol, mabuterol, epimethylenediol and norandrosterone, without loss of derivatized metabolites signal. Later. eluting analytes, such as the stanozolol metabolites, furazabol and oxandrolone were not affected. Temperatures below 140 degrees C. resulted in partial derivatization for some analytes mainly stanozolol related structures. Therefore evaluation of derivatization conditions as occurring in three steps, the vial, vaporization chamber and capillary column, was thoroughly assessed. The new program temperature improves the signal-to-noise ratio for some compounds and shows adequate resolution for endogenous compounds. Some of the difficult key separations necessary for doping control enforcement were also obtained with the proposed method.     

A new regularization of equilibrium problems on Hadamard manifolds: applications to theories of desires

In this paper, we introduce a new proximal algorithm for equilibrium problems on a genuine Hadamard manifold, using a new regularization term. We first extend recent existence results by considering pseudomonotone bifunctions and a weaker sufficient condition than the coercivity assumption. Then, we consider the convergence of this proximal-like algorithm which can be applied to genuinely Hadamard manifolds and not only to specific ones, as in the recent literature. A striking point is that our new regularization term have a clear interpretation in a recent “variational rationality” approach of human behavior. It represents the resistance to change aspects of such human dynamics driven by motivation to change aspects. This allows us to give an application to the theories of desires, showing how an agent must escape to a succession of temporary traps to be able to reach, at the end, his desires.

     

Characterization of two irradiation positions for fission track dating at the Lena Triga Mark II reactor

In the present paper the use of two natural uranium dosimeters is described. Data are compared with fluence values obtained by using NIST glass standards and the traditional activation of metal foils. Finally an example is reported for application of neutron dosimetry to the dating of the Fish Canyon Tuff age standard.