Autonomous Vehicles within the Urban Space and Transport Security Challenges: Legal Aspect

Nowadays autonomous vehicles are getting widespread use in different parts of the world. In some countries, they are being tested within the urban traffic whereas other counties have been already operating them. Such vehicles possess a number of obvious advantages. We cannot but agree that these cars are the future. However, before complete implementation and mass use of autonomous transport on public roads, it is necessary to resolve a number of problems concerning their safety towards road-users. Except for ethical, economic, and other aspects, it also embraces the legal aspect

The Interaction of an 180 degree Ferroelectric Domain Wall with a Biased Scanning Probe Microscopy Tip: Effective Wall Geometry and Thermodynamics in Ginzburg-Landau-Devonshire Theory

The interaction of ferroelectric 180 degree domain wall with a strongly inhomogeneous electric field of biased Scanning Probe Microscope tip is analyzed within continuous Landau-Ginzburg-Devonshire theory. Equilibrium shape of the initially flat domain wall boundary bends, attracts or repulses from the probe apex, depending on the sign and value of the applied bias. For large tip-wall separations, the probe-induced domain nucleation is possible. The approximate analytical expressions for the polarization distribution are derived using direct variational method. The expressions provide insight how the equilibrium polarization distribution depends on the wall finite-width, correlation and depolarization effects, electrostatic potential distribution of the probe and ferroelectric material parameters.Comment: 37 pages, 9 figures, 4 Appendices, to be submitted to Phys. Rev.

Domain wall conduction in multiaxial ferroelectrics

The conductance of domain wall structures consisting of either stripes or cylindrical domains in multi-axial ferroelectric-semiconductors is analyzed. The effects of the domain size, wall tilt and curvature, on charge accumulation, are analyzed using the Landau-Ginsburg Devonshire (LGD) theory for polarization combined with Poisson equation for charge distributions. Both the classical ferroelectric parameters including expansion coefficients in 2-4-6 Landau potential and gradient terms, as well as flexoelectric coupling, inhomogeneous elastic strains and electrostriction are included in the present analysis. Spatial distributions of the ionized donors, free electrons and holes were found self-consistently using the effective mass approximation for the respective densities of states. The proximity and size effect of the electron and donor accumulation/depletion by thin stripe domains and cylindrical nanodomains are revealed. In contrast to thick domain stripes and thicker cylindrical domains, in which the carrier accumulation (and so the static conductivity) sharply increases at the domain walls only, small nanodomains of radius less then 5-10 correlation length appeared conducting across entire cross-section. Implications of such conductive nanosized channels may be promising for nanoelectronics.Comment: 39 pages, 11 figures, 3 tables, 4 appendice

Thermodynamics of nanodomain formation and breakdown in Scanning Probe Microscopy: Landau-Ginzburg-Devonshire approach

Thermodynamics of tip-induced nanodomain formation in scanning probe microscopy of ferroelectric films and crystals is studied using the Landau-Ginzburg-Devonshire phenomenological approach. The local redistribution of polarization induced by the biased probe apex is analyzed including the effects of polarization gradients, field dependence of dielectric properties, intrinsic domain wall width, and film thickness. The polarization distribution inside subcritical nucleus of the domain preceding the nucleation event is very smooth and localized below the probe, and the electrostatic field distribution is dominated by the tip. In contrast, polarization distribution inside the stable domain is rectangular-like, and the associated electrostatic fields clearly illustrate the presence of tip-induced and depolarization field components. The calculated coercive biases of domain formation are in a good agreement with available experimental results for typical ferroelectric materials. The microscopic origin of the observed domain tip elongation in the region where the probe electric field is much smaller than the intrinsic coercive field is the positive depolarization field in front of the moving counter domain wall. For infinitely thin domain walls local domain breakdown through the sample depth appears. The results obtained here are complementary to the Landauer-Molotskii energetic approach.Comment: 35 pages, 8 figures, suplementary attached, to be submitted to Phys. Rev.

Repolarization of ferroelectric superlattices BaZrO3/BaTiO3

The study was supported by Russian Science Foundation, project No. № 17-72-20105

Precise Measurement of the Pi+ -> Pi0 e+ nu Branching Ratio

Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare Pi+ -> Pi0 e+ Nu,(pi_beta) decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed pi_beta decays to the number of observed Pi+ -> e+ Nu, (pi_{e2}) decays. We find the value of Gamma(Pi+ -> Pi0 e+ Nu)/Gamma(total) = [1.036 +/- 0.004(stat.) +/- 0.004(syst.) +/- 0.003(pi_{e2})] x 10^{-8}$, where the first uncertainty is statistical, the second systematic, and the third is the pi_{e2} branching ratio uncertainty. Our result agrees well with the Standard Model prediction.Comment: 4 pages, 5 figures, 1 table, revtex4; changed content; updated analysi

Drilling of deep and ultra-deep wells for prospecting and exploration of new raw mineral fields

Scientific and technological progress over the last century has led to an enormous increase in the consumption of minerals, including energy resources. Most of the exploited oil and gas fields are already considerably depleted, so it is necessary to search for new hydrocarbon resources, particularly at great depths. Deep drilling plays a special role in solving this problem. The article considers the world and Russian experience of ultra-deep wells drilling. The me-thods and technologies used in the construction of wells, as well as complications and accidents occurring during their drilling were analyzed. The analysis revealed that the existing limitations for drilling parameters of deep and ultra-deep wells are caused by the technical characteristics of surface and bottomhole drilling equipment, which do not meet the extreme drilling conditions. The directions for development of deep and ultra-deep well drilling machinery and technologies are suggested. The notion of extreme rock and geological drilling conditions is introduced, which describes drilling in conditions of hydrostatic pressure of flushing fluid column and high bottomhole temperature both at stable and unstable wellbore conditions, coming close to the upper limit of operating technical characteristics of bottomhole assembly, the drill string and flushing fluid

Precise Measurement of pi+ -> e+ nu Branching Ratio

The PEN Collaboration is conducting a new measurement of the pi+ -> e+ nu branching ratio at the Paul Scherrer Institute, with the goal uncertainty of delta B/B(pie2)=5E-4 or lower. At present, the combined accuracy of all published pie2 decay measurements lags behind the theoretical calculation by a factor of 40. In this contribution we report on the PEN detector configuration and its performance during two development runs done in 2007 and 2008.Comment: pdflatex, 11 pages, 5 figures, to be published in "Progress in High-Energy Physics and Nuclear Safety", NATO Science for Peace Series: B - Physics and Biophysic

Spin physics with antiprotons

New possibilities arising from the availability at GSI of antiproton beams, possibly polarised, are discussed. The investigation of the nucleon structure can be boosted by accessing in Drell-Yan processes experimental asymmetries related to cross-sections in which the parton distribution functions (PDF) only appear, without any contribution from fragmentation functions; such processes are not affected by the chiral suppression of the transversity function $h_1(x)$. Spin asymmetries in hyperon production and Single Spin Asymmetries are discussed as well, together with further items like electric and magnetic nucleonic form factors and open charm production. Counting rates estimations are provided for each physical case. The sketch of a possible experimental apparatus is proposed.Comment: Presented for the proceedings of ASI "Spin and Symmetry", Prague, July 5-10, 2004, to be published in Czech. J. Phys. 55 (2005