53 research outputs found
Nonlinear Effects in Rolling Mills Dynamics
This paper intends to describe nonlinear effects occurring in rolling mills dynamics. That is necessarily for
vibrations damping and reliable diagnostics of rolling mills equipment under non-stationary working
conditions. Three types of nonlinear effects are investigated taking place in drivelines and stands of different
design, namely, transient torsional vibrations in hot rolling mills, chatter vibrations in tandem cold rolling
mills and parametrical vibrations in high-speed wire and rod rolling mills. The procedure is proposed for
natural frequencies identification when short transient torque signals restrict application of the Fourier
transform. Some considerations given on using nonlinear effects for wear diagnostics and vibrations control
based on natural frequencies and modes analysis of multi-body systems
On calculating the mean values of quantum observables in the optical tomography representation
Given a density operator the optical tomography map defines a
one-parameter set of probability distributions on the real line allowing to reconstruct . We
introduce a dual map from the special class of quantum observables
to a special class of generalized functions such that the
mean value is given by the formula
. The class
includes all the symmetrized polynomials of canonical variables
and .Comment: 8 page
Optical Tomography of Photon-Added Coherent States, Even/Odd Coherent States and Thermal States
Explicit expressions for optical tomograms of the photon-added coherent
states, even/odd photon-added coherent states and photon-added thermal states
are given in terms of Hermite polynomials. Suggestions for experimental
homodyne detection of the considered photon states are presented.Comment: 10 pages, 8 figure
Simulating the Spread of Peste des Petits Ruminants in Kazakhstan Using the North American Animal Disease Spread Model
In this study, we simulated the potential spread of Peste des Petits Ruminants (PPR) between small ruminant (SR) farms in the Republic of Kazakhstan (RK) in case of the disease’s introduction into the country. The simulation was based on actual data on the location and population of SR farms in the RK using the North American Animal Disease Spread Model (NAADSM). The NAADSM employs the stochastic simulations of the between-farm disease spread predicated on the SIR compartmental epidemic model. The most important epidemiological indicators of PPR, demography of SR farms, and livestock management characteristics in the RK were used for model parameterization. This article considers several scenarios for the initial introduction of PPR into the territory of Kazakhstan, based on previously identified high-risk regions and varying sizes of initially infected farms. It is demonstrated that the duration and size of the outbreak do not depend on the size of initially infected farms but rather depend on the livestock concentration and number of farms in the affected area. This implies that the outbreak may affect the largest number of farms in the case of introduction of the disease into farms in southern Kazakhstan. However, even in the most unfavorable scenario, the total number of affected farms does not exceed 2.4% of all SR farms in the RK. The size of the affected area is, in most cases, no larger than an averaged 2-level administrative division’s size, which suggests the scale of a local epidemic. The chosen model provides ample opportunity to study the impact of different control and prevention measures on the spread of PPR as well as to assess the potential economic damage
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