Derivative based global sensitivity measures

The method of derivative based global sensitivity measures (DGSM) has recently become popular among practitioners. It has a strong link with the Morris screening method and Sobol' sensitivity indices and has several advantages over them. DGSM are very easy to implement and evaluate numerically. The computational time required for numerical evaluation of DGSM is generally much lower than that for estimation of Sobol' sensitivity indices. This paper presents a survey of recent advances in DGSM concerning lower and upper bounds on the values of Sobol' total sensitivity indices $S\_{i}^{tot}$. Using these bounds it is possible in most cases to get a good practical estimation of the values of $S\_{i}^{tot}$. Several examples are used to illustrate an application of DGSM

On the appearance of space temperature electric structures in hyperconductors under high magnetic fields

As part of the study of low temperature galvanomagnetic properties of high purity A1 in the Corbino geometry the voltage-current characteristics (IV) under external transverse magnetic field in the regime of given current revealed the effects of voltage stabilization. Here we attempt to ascribe these phenomena to appearance in the sample of bulk temperature structures characteristic of highly nonequilibrium systems. Joule’s heat of flowing electric current gives rise to disk warming. We also discuss the problems of the influence of warming in disks on the phenomena of electric transport with allowance for own magnetic fields being generated in disk

Trial of liquidation cementation of boreholes at Carpathians oil and gas deposits

Complex geological structure as well as long-term intensive operation of oil and gas deposits in Borislav-Pokutska zone of Carpathians leads to changes in thermo-dynamical parameters of pools, rock deformation and, as a result, to crippling of the boreholes and creasing and damaging of boring casing. The abovementioned actions not only complicate extraction of oil and gas but increase the technological charge on the environment. In this study 3 types of materials were investigated: PCT-I-100 – traditional tamping cement, CREA and CREA-LF tamping mixes produced by dry mixing technology that were designed by authors. Dry mixes are characterized by higher level of SiO2 because of addition of milled sand and provide better cementation quality. Developed materials are characterized by lower dehydration and water reduction, thanks to clearly chosen composition and modern chemical admixtures usage. The method of borehole eliminative cementation is also presented by authors

From Agent to Active Sense : Was there an Augustinianism-Averroisant?

Peer reviewe

Derivative based global sensitivity measures

International audienceThe method of derivative based global sensitivity measures (DGSM) has recently become popular among practitioners. It has a strong link with the Morris screening method and Sobol' sensitivity indices and has several advantages over them. DGSM are very easy to implement and evaluate numerically. The computational time required for numerical evaluation of DGSM is generally much lower than that for estimation of Sobol' sensitivity indices. This paper presents a survey of recent advances in DGSM concerning lower and upper bounds on the values of Sobol' total sensitivity indices $S_{i}^{tot}$. Using these bounds it is possible in most cases to get a good practical estimation of the values of $S_{i}^{tot}$. Several examples are used to illustrate an application of DGSM

Optical constatnts of yttrium-iron garnet single-crystal film strucrures

Light-attenuation spectra of yttrium–iron gar-net single-crystal film structures grown on a gallium–gadolinium garnet substrate by liquid-phase epitaxy from the undercooled solution in the melt have been studied and compared with those of bulk yttrium–iron garnet samples. The calculated optical constants are discussed tak-ing into account the influence of crystal field on the splitting of the energy states of iron ions in the film samples.

Novel concept of hyperconducting concentrator of magnetic energy

The properties of Hall drift of electrons and generation of respective self magnetic field are examined. The problem of design of high effective cryogenic generator of magnetic field advances the requirement of optimization of magnetic system geometry for the most magnitude of field to be obtained in the same volume at the same energy supply. Besides an electron drift along electric field there is a transverse drift of carriers stimulated by Lorentz force if magnetic field is applied. Generally transverse Hall drift as a source of magnetic field is ignored. A paper is represented here to indicate a novel way of improvement of magnetic system arrangement and efficiency. It is based on validity of use the energy concentrator made from high purity aluminum. Such concentrator may be installed into traditional solenoid and as a consequence the magnitude of magnetic field will increase. An experiment on A1 disk conductors having inner and outer concentric current leads is made in coaxial magnetic field of 8T. Current density is sufficient to achieve a boiling crisis of helium. It is shown that magnetic field of solenoid will be increased in volume of concentrator in accordance with power type law instead of summation taking place in many layer solenoid system. The benefits and advantages of application of magnetic field of Hall drift arc discussed. Parameters together with all necessary requirement for operation are represented for cryogenic range of temperature 4.2–30 K. Research is supported by Fund of Fundamental Investigations of the Republic of Belarus