High-order approximations of three-phase-lag heat conduction model: Some qualitative results

This article deals with some high-order approximations of the three-phase-lag heat transfer model aiming, at first, to identify the restrictions that make them well-posed consistence. Consequently, a first result about the uniqueness and continuous dependence of the solutions with respect to the given initial data and to the supply term is established for the related initial boundary value problems. Subsequently, to provide a more comprehensive analysis of the model, some further spatial decay results are established, this time conveniently relaxing the hypotheses about the delay times and the thermal conductivities. More precisely, a theorem of influence domain is proved for the wave propagating models and an exponential decaying estimate of Saint-Venant type is established for the diffusive models.     

Deflection of ultrahigh energy particle beams by repeated reflections in bent monocrystals

Bent silicon monocrystals are used today in the planar channeling mode for beam extraction and collimation at large accelerators. Volume reflection is more efficient than channeling, though it has a small deflection angle. A device for repeated deflection of a proton beam using a few bent silicon strips in the reflection mode is described in this paper. Sequential silicon strips on the surface of a thick plate are bent by internal stresses in the crystal material resulting from the Twyman effect. As shown by the Monte Carlo calculations, this method for deflecting the beam is optimal for the teraelectronvolt energy range.     

Formation of coulomb clusters from charged diamagnetic microparticles in inhomogeneous magnetic field

The possibility of levitating Coulomb clusters formed by charged diamagnetic microparticles in an inhomogeneous magnetic field has been theoretically substantiated and experimentally confirmed. An experimental setup is described, in which the Coulomb clusters can be formed from charged graphite particles 100–300 μm in size and maintained stable between the poles of an electromagnet generating a magnetic field with induction B ∼ 10⁴ G and gradient |∂B| ∼ 10⁵ G/cm.     

Design and tuning of a 40-MeV electron linear accelerator

The 40-MeV electron linear accelerator RELUS-6 with a 100-mA pulse current has been designed. The standing wave accelerator with a biperiodic accelerating structure is composed of four sections and is powered from two 6-MW pulse klystrons. The operating frequency is 2856 MHz. The total length of the accelerating structure is 2.73 m. Calculations have been performed with the aim of selecting the lengths of the first three cells in the first accelerating section and the values of the accelerating field in them, so that the width of the energy spectrum at the end of the accelerator is 2%. The geometry of the accelerating structure and the power input cells has been designed. Four accelerating structures have been manufactured based on the simulation results. The structures have been tuned to the operating frequency, the predetermined accelerating field distribution, and a fixed coupling between the feed waveguide and the accelerating section.     

Static characteristics of conical multiple-wedge hydrodynamic liquid-friction bearings

Formulas are proposed for the state characteristics of conical multiple-wedge hydrodynamic liquid-friction bearings, with variation of the heat-transfer properties, a two-phase lubricant state, and variation in the load-carrying capacity, lubricant flow rate, and power loss on friction and pumping.     

Efficiency in generalised V-KT-pseudoinvex control problems

ABSTRACT

In this paper, (strongly) b-V-KT-pseudoinvex multidimensional control problems are considered. Concretely, we introduce a generalised condition on the functionals involved in a multidimensional vector control problem and prove that a (strongly) b-V-KT-pseudoinvex multidimensional control problem is characterized so that all Kuhn–Tucker points are efficient solutions. In addition, the theoretical results derived in this paper are illustrated with an application.     

Chronic renal insufficiency: 1) adaptation of nephron function in chronic renal insufficiency and 2) progression of chronic renal insufficiency

In chronic renal insufficiency resulting from destruction of the vast majority of nephrons, the surviving nephrons adapt their functions to the conditions of vigorous haemodynamic and osmolar overloads. They acquire an appropriate behaviour to preserve the principal renal functions and to achieve the balance of inner space. In the long period of time, similarly as in healthy people. Glomerulotubular balance as well as tubuloglomerular balance distinguish the remaining nephron function, while autoregulation of perfusion pressure along the glomerulus rapidly vanishes. All three regulation mechanisms are characteristic of the nephron function under physiologic conditions. Intense work of the remaining nephrons in chronic renal failure is under the high level controls of the group of hormones, among them are rennin-angiotensin system, arginine-vasopressin and atrial natriuretic peptide playing very important and particular roles. Comparison of different published studies emerge the idea that chronically increased arginine-vasopressin levels in chronic renal failure could block the autoregulation of blood flow and hydraulic pressure in glomeruli, which together with other mediator actions give high and fluctuating tense within remaining glomeruli, during every single cardiac cycle. It is probably the main event in the further course of kidney disease progression resulting in definite damage of the overloaded nephrons. Angiotensin II is one of reliably recognised mediators of unfavourable outcome in the process of nephron adaptation in chronic renal failure. Knowing the pathophysiologic processes in the remaining functionally adapted nephrons in chronic renal insufficiency determines a more adequate therapeutic approach in these patients.     

Helium boiling crisis with a stepped increase in heating capacity

Results are presented from a study of the effect of saturation pressure on the nonsteady critical heat flux during the boiling of liquid helium in a large volume.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 1, pp. 16–18, January, 1985.     

Effect of magnetized ferromagnetic film on electrodynamic characteristics of a meander microstrip line

The results of an experimental investigation of electrodynamic characteristics of a meander microstrip line with a ferromagnetic film are presented for different values of an external magnetic field. It is found that, in the presence of a ferrite film, higher-order modes caused by perturbation of corresponding modes of a multilayered meander line are excited in the passband of a higher-order mode of the meander line. These modes propagate in dielectric substrates of the meander line and the ferromagnetic film. The effect of transmission of the active power in the stopband of the meander line with a ferromagnetic film is discovered. This effect also arises in the case of excitation of magnetostatic waves.