1,091 research outputs found
MANAGEMENT ENVIRONMENTAL ACTIVITIES EFFICIENCY IN THE RAILWAY ENTERPRISES
The article describes the development trend of environmental management systems in railway transport and the importance of the impact of transport factors to ensure ecological and economic security of the society. Development management instrumentation of processing of environmental systems in railway transport is aimed at maintaining the global interest in reducing pollution and possible damage of the environment to ensure ecological and economic security of the country. The main objective of the development of environmental management systems in railway transport should be inextricably linked with the main goal of the human ecology. The basis of the human ecology is to maintain equilibrium within humanity and the outside world and its environment. Improving environmental activities of the company is achieved by applying a systematic approach. The proposed criteria for evaluating the best project options and directions of improvement of greening the economy are the basis for the establishment of a mechanism of transition to sustainable development of railway industry. The authors of the analysis of ecological and economic indicators of the enterprises of the railway industry and ecological and economic assessment of investment in the environmental management system in railway transport from In the article the formation of approaches to environmental management decisions at the enterprises of the railway industry was substantiated.The article describes the development trend of environmental management systems in railway transport and the importance of the impact of transport factors to ensure ecological and economic security of the society. Development management instrumentation of processing of environmental systems in railway transport is aimed at maintaining the global interest in reducing pollution and possible damage of the environment to ensure ecological and economic security of the country. The main objective of the development of environmental management systems in railway transport should be inextricably linked with the main goal of the human ecology. The basis of the human ecology is to maintain equilibrium within humanity and the outside world and its environment. Improving environmental activities of the company is achieved by applying a systematic approach. The proposed criteria for evaluating the best project options and directions of improvement of greening the economy are the basis for the establishment of a mechanism of transition to sustainable development of railway industry. The authors of the analysis of ecological and economic indicators of the enterprises of the railway industry and ecological and economic assessment of investment in the environmental management system in railway transport from In the article the formation of approaches to environmental management decisions at the enterprises of the railway industry was substantiated
Extra Spin-Wave mode in Quantum Hall systems. Beyond the Skyrmion Limit
We report on the observation of a new spin mode in a quantum Hall system in
the vicinity of odd electron filling factors under experimental conditions
excluding the possibility of Skyrmion excitations. The new mode having
presumably zero energy at odd filling factors emerges at small deviations from
odd filling factors and couples to the spin-exciton. The existence of an extra
spin mode assumes a nontrivial magnetic order at partial fillings of Landau
levels surrounding quantum Hall ferromagnets other then the Skyrmion crystal.Comment: 9 pages, 4 figure
Spectroscopy of HS: evidence of a new energy scale for superconductivity
The discovery of a superconducting phase in sulfur hydride under high
pressure with a critical temperature above 200 K has provided a new impetus to
the search for even higher . Theory predicted and experiment confirmed
that the phase involved is HS with Im-3m crystal structure. The observation
of a sharp drop in resistance to zero at , its downward shift with
magnetic field and a Meissner effect confirm superconductivity but the
mechanism involved remains to be determined. Here, we provide a first optical
spectroscopy study of this new superconductor. Experimental results for the
optical reflectivity of HS, under high pressure of 150 GPa, for several
temperatures and over the range 60 to 600 meV of photon energies, are compared
with theoretical calculations based on Eliashberg theory using DFT results for
the electron-phonon spectral density F(). Two significant
features stand out: some remarkably strong infrared active phonons at
160 meV and a band with a depressed reflectance in the superconducting state in
the region from 450 meV to 600 meV. In this energy range, as predicted by
theory, HS is found to become a better reflector with increasing
temperature. This temperature evolution is traced to superconductivity
originating from the electron-phonon interaction. The shape, magnitude, and
energy dependence of this band at 150 K agrees with our calculations. This
provides strong evidence of a conventional mechanism. However, the unusually
strong optical phonon suggests a contribution of electronic degrees of freedom.Comment: 10 pages, 8 figures. Main manuscript and supplementary informatio
The nonlinear time-dependent response of isotactic polypropylene
Tensile creep tests, tensile relaxation tests and a tensile test with a
constant rate of strain are performed on injection-molded isotactic
polypropylene at room temperature in the vicinity of the yield point. A
constitutive model is derived for the time-dependent behavior of
semi-crystalline polymers. A polymer is treated as an equivalent network of
chains bridged by permanent junctions. The network is modelled as an ensemble
of passive meso-regions (with affine nodes) and active meso-domains (where
junctions slip with respect to their positions in the bulk medium with various
rates). The distribution of activation energies for sliding in active
meso-regions is described by a random energy model. Adjustable parameters in
the stress--strain relations are found by fitting experimental data. It is
demonstrated that the concentration of active meso-domains monotonically grows
with strain, whereas the average potential energy for sliding of junctions and
the standard deviation of activation energies suffer substantial drops at the
yield point. With reference to the concept of dual population of crystalline
lamellae, these changes in material parameters are attributed to transition
from breakage of subsidiary (thin) lamellae in the sub-yield region to
fragmentation of primary (thick) lamellae in the post-yield region of
deformation.Comment: 29 pages, 12 figure
Fourth Order Algorithms for Solving the Multivariable Langevin Equation and the Kramers Equation
We develop a fourth order simulation algorithm for solving the stochastic
Langevin equation. The method consists of identifying solvable operators in the
Fokker-Planck equation, factorizing the evolution operator for small time steps
to fourth order and implementing the factorization process numerically. A key
contribution of this work is to show how certain double commutators in the
factorization process can be simulated in practice. The method is general,
applicable to the multivariable case, and systematic, with known procedures for
doing fourth order factorizations. The fourth order convergence of the
resulting algorithm allowed very large time steps to be used. In simulating the
Brownian dynamics of 121 Yukawa particles in two dimensions, the converged
result of a first order algorithm can be obtained by using time steps 50 times
as large. To further demostrate the versatility of our method, we derive two
new classes of fourth order algorithms for solving the simpler Kramers equation
without requiring the derivative of the force. The convergence of many fourth
order algorithms for solving this equation are compared.Comment: 19 pages, 2 figure
The space physics environment data analysis system (SPEDAS)
With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (www.spedas.org), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.Published versio
Non-equilibrium phase transition in a sheared granular mixture
The dynamics of an impurity (or tracer particle) immersed in a dilute
granular gas under uniform shear flow is investigated. A non-equilibrium phase
transition is identified from an exact solution of the inelastic Boltzmann
equation for a granular binary mixture in the tracer limit, where the impurity
carries either a vanishing (disordered phase) or a finite (ordered phase)
fraction of the total kinetic energy of the system. In the disordered phase,
the granular temperature ratio (impurity "temperature" over that of the host
fluid) is finite, while it diverges in the ordered phase. To correctly capture
this extreme violation of energy equipartition, we show that the picture of an
impurity enslaved to the host fluid is insufficient
The use of titanium alloys for details of downhole hammers
The influence of cementation technology of titanium alloy Ti-Al-Mn on its wear resistance is studied. It is established that after lubrication a friction pair with mineral oil the wear resistance of the cemented titanium alloy is comparable to wear resistance of the tempered steel 12HN3A, and in water medium surpasses it by 1.5 times. Decrease in the tendency to seizure with steel is the main reason for increase of wear resistance of titanium alloy. Industrial tests of the ASH43 hammer have shown that the use of titanium alloys for the manufacture of hammer strikers allows to increase impact capacity by 1.5 times and to increase drilling rate by 30 % compared to hammers with steel strikers
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts.
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes
High-Energy Approach for Heavy-Ion Scattering with Excitations of Nuclear Collective States
A phenomenological optical potential is generalized to include the Coulomb
and nuclear interactions caused by the dynamical deformation of its surface. In
the high-energy approach analytical expressions for elastic and inelastic
scattering amplitudes are obtained where all the orders in the deformation
parameters are included. The multistep effect of the 2 rotational state
excitation on elastic scattering is analyzed. Calculations of inelastic cross
sections for the O ions scattered on different nuclei at about hundred
Mev/nucleon are compared with experimental data, and important role of the
Coulomb excitation is established.Comment: 9 pages; 3 figures. Submitted to the Physics of Atomic Nucle
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