New Aspects of Variable-range-hopping Conductivity in Doped Polyaniline

Temperature, T, dependence of the electrical conductivity, σ, of own-made polyaniline pellets, highly doped either by HCl or by dodecylbenzenesulphonic acid, is discussed. For the both dopants, a variable-range-hopping exponent 2/5 is found below T* ≈ 200 − 250 K. This result can be understood on the basis of a recent theory of Fogler, Teber and Shklovskii which takes into account Coulomb correlations in a three-dimensional system of chain-like conductors, predicting a power-law density of states for charge excitations around the Fermi energy. At T > T *, the σ(T) curves are steeper, implying a tendency towards nearest-neighbour hopping by a reduction of the average hopping length.</p

Comparative analysis of the ellipsoid approximation with the sphere

The paper analyzes the approximation of the ellipsoid by the sphere. Earth is a space body with a mathematically irregular shape, so idealized smooth surfaces are used for calculations. The first is the geoid, a smooth, equipotential surface that best approximates mean sea level. However, the geoid does not have an analytical form and is unsuitable for many applications, so an ellipsoid is used for approximation. In applications where high accuracy is not required (e.g., with small scale maps), the ellipsoid is approximated by a sphere. The radius of the sphere can be calculated in three ways: according to the equivalent volume criterion, according to the equivalent surface criterion, or as the mean value of the three semi-axes of the ellipsoid. All three methods of approximation were tested by calculating the length of the geodetic line on the ellipsoid, the orthodrome on the spheres and then the error. Also, the influence of latitude on the error value was tested. For three different values of geographic latitude, the lengths of geodetic lines up to one hundred points were calculated (using the Bessel method for solving the second main geodetic task on the ellipsoid), as well as the lengths of the orthodromes on the spheres, with the radii of the spheres determined in the three mentioned ways. The obtained results were then analyzed and discussed

A study of aerodynamic noise in air duct systems with turning vanes

Buka je jedan od problema u mnogim industrijama. U ovom radu prikazana je analiza aerodinamički nastale buke koja se javlja pri strujanjima vazduha preko usmerivača vazduha oblika aeroprofila u vazdušnim kanalima. Na osnovu Proudmanove jednačine i Lajthilove akustične analogije širokopojasni nivo buke u vazdušnom kanalu može biti izračunat. Za modeliranje turbulentnog modela, k - e turbulentni model je korišćen a potrebne konstante su eksperimentalno određene merenjem u aerotunelu za podzvučne brzine, nakon kojih su vršena merenja buke za u neposrednoj blizini usmerivača vazduha oblika aeroprofila. Nekoliko rešenja je analizirano, kanal sa unutrašnjim aeroprofilom, kanal sa centralnim aeroprofilom, kanal sa spoljašnjim aeroprofilom kao i kombinacija prethodnih slučajeva. Analizom dobijenih rezultata, a u cilju ispunjavanja svih zakonskih propisa koji se tiču industrijske buke, koji postaju sve striktniji, akustična analiza i projektovanje moraju biti primenjeni u većini industrijskih sistema jer buka predstavlja opasnost po zdravlje radnika u radnom okruženju.Noise is becoming one of the problems in many industrial applications. In this paper the aerodynamic noise in air duct system that arises from air flow passing over a surface of turning vanes is investigated. Based on Proudman's formula using Lighthill's acoustic analogy broadband acoustic noise model can be predicted. To model the turbulent flow in an air duct k - e turbulent model is used and required constants are obtained experimentally in a low speed wind tunnel followed by noise measurement in the vicinity of deflected airfoil. Several designs are investigated: Inner airfoil in the duct elbow, center positioned air foil, outer positioned and the overall combination of all previous cases. It was found that in order to satisfy all noise requirements and regulation, which are becoming more strict nowadays, the acoustic analysis and design must be performed in most industrial systems since the noise levels arising from the operating industrial equipment may represent occupational and health hazard

A study of aerodynamic noise in air duct systems with turning vanes

Buka je jedan od problema u mnogim industrijama. U ovom radu prikazana je analiza aerodinamički nastale buke koja se javlja pri strujanjima vazduha preko usmerivača vazduha oblika aeroprofila u vazdušnim kanalima. Na osnovu Proudmanove jednačine i Lajthilove akustične analogije širokopojasni nivo buke u vazdušnom kanalu može biti izračunat. Za modeliranje turbulentnog modela, k - e turbulentni model je korišćen a potrebne konstante su eksperimentalno određene merenjem u aerotunelu za podzvučne brzine, nakon kojih su vršena merenja buke za u neposrednoj blizini usmerivača vazduha oblika aeroprofila. Nekoliko rešenja je analizirano, kanal sa unutrašnjim aeroprofilom, kanal sa centralnim aeroprofilom, kanal sa spoljašnjim aeroprofilom kao i kombinacija prethodnih slučajeva. Analizom dobijenih rezultata, a u cilju ispunjavanja svih zakonskih propisa koji se tiču industrijske buke, koji postaju sve striktniji, akustična analiza i projektovanje moraju biti primenjeni u većini industrijskih sistema jer buka predstavlja opasnost po zdravlje radnika u radnom okruženju.Noise is becoming one of the problems in many industrial applications. In this paper the aerodynamic noise in air duct system that arises from air flow passing over a surface of turning vanes is investigated. Based on Proudman's formula using Lighthill's acoustic analogy broadband acoustic noise model can be predicted. To model the turbulent flow in an air duct k - e turbulent model is used and required constants are obtained experimentally in a low speed wind tunnel followed by noise measurement in the vicinity of deflected airfoil. Several designs are investigated: Inner airfoil in the duct elbow, center positioned air foil, outer positioned and the overall combination of all previous cases. It was found that in order to satisfy all noise requirements and regulation, which are becoming more strict nowadays, the acoustic analysis and design must be performed in most industrial systems since the noise levels arising from the operating industrial equipment may represent occupational and health hazard

The large area detector onboard the eXTP mission

The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we will provide an overview of the LAD instrument design, its current status of development and anticipated performance

Characterisation of age and polarity at onset in bipolar disorder

Background Studying phenotypic and genetic characteristics of age at onset (AAO) and polarity at onset (PAO) in bipolar disorder can provide new insights into disease pathology and facilitate the development of screening tools. Aims To examine the genetic architecture of AAO and PAO and their association with bipolar disorder disease characteristics. Method Genome-wide association studies (GWASs) and polygenic score (PGS) analyses of AAO (n = 12 977) and PAO (n = 6773) were conducted in patients with bipolar disorder from 34 cohorts and a replication sample (n = 2237). The association of onset with disease characteristics was investigated in two of these cohorts. Results Earlier AAO was associated with a higher probability of psychotic symptoms, suicidality, lower educational attainment, not living together and fewer episodes. Depressive onset correlated with suicidality and manic onset correlated with delusions and manic episodes. Systematic differences in AAO between cohorts and continents of origin were observed. This was also reflected in single-nucleotide variant-based heritability estimates, with higher heritabilities for stricter onset definitions. Increased PGS for autism spectrum disorder (β = −0.34 years, s.e. = 0.08), major depression (β = −0.34 years, s.e. = 0.08), schizophrenia (β = −0.39 years, s.e. = 0.08), and educational attainment (β = −0.31 years, s.e. = 0.08) were associated with an earlier AAO. The AAO GWAS identified one significant locus, but this finding did not replicate. Neither GWAS nor PGS analyses yielded significant associations with PAO. Conclusions AAO and PAO are associated with indicators of bipolar disorder severity. Individuals with an earlier onset show an increased polygenic liability for a broad spectrum of psychiatric traits. Systematic differences in AAO across cohorts, continents and phenotype definitions introduce significant heterogeneity, affecting analyses

Quantum oscillations in a lead chalcogenide three-dimensional Dirac system

The de Haas–van Alphen (dHvA) and the Shubnikov–de Haas (SdH) oscillations were used to probe the properties of the Fermi surface in single crystals of Pb0.83Sn0.17Se with reduced charge concentration. Pronounced low-frequency oscillations of ∼8 T in the [001] direction were observed, confirming the single Fermi surface cross section. Due to the low effective charge concentration, the ultraquantum limit is reached already at ∼10 T. We observe π-Berry phase shift in the phase of both dHvA and SdH oscillations, which confirms the 3D Dirac nature of the energy band dispersion. In the construction of the Landau level diagram we use a combined indexing method for conductivity, magnetic susceptibility, and magnetization, which is based on the indexing used in the topological insulators. Moreover, the reliability of the indexing method is increased because we use, beside minima and maxima, zeros of the oscillations as well. Different microscopic parameters were calculated from the quantum oscillations in the magnetization, conductivity, and resistivity

Biomass-React, il progetto che valorizza l’impiego della biomassa forestale

L’iniziativa è in fase di realizzazione nel Comune di Asiago (BL) e coinvolge alcune realtà del territorio che intendono avviare un processo virtuoso per favorire la nascita di una filiera di approvvigionamento locale di cippato forestale supportata da un’apposita certificazion

Reliability of Information Translation.

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Rozvaha o moznostech uplatneni metod predikcni diagnostiky pri reseni dopravnich situaci.

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi