Relative Yield and Period of Individual Groups of Delayed Neutrons in 233U, 235U, and 239Pu Fission by Epithermal Neutrons

The relative yield of delayed neutrons and the half-life of their precursor nuclei in fissioning of ²³³U, ²³⁵U, and ²³⁹Pu by epithermal neutrons are measured on a setup which is based on a KG-2.5 electrostatic accelerator. The experimental samples are irradiated in a polyethylene cube, one face of which is irradiated by a neutron beam consisting of T(p, n)³He neutrons. A procedure is developed for averaging the group parameters of delayed neutrons from different series of measurements, taking account of their correlation. A comparative analysis of the data of this work and in ENDF/BVI in terms of the average half-life of the precursor nuclei of the delayed neutrons and using the dependence of the reactivity on the asymptotic period of the reactor is performed.It is shown that the data of this work agree, to within the uncertainty limits, with the recommended experimental data and differ substantially from the ENDF/BVI data.     

Radiological hazard of long-lived spallation products in accelerator-driven system

The present paper focuses on analysis of radiological hazard of spallation products that appears to be an important factor that might affect the choice of beam/target performance in designing the accelerator-driven systems. The analysis is done in terms of toxicity expressed in units of Annual Limit on Intake (ALI). It reveals the significant contribution of alpha emitting rare earths (¹⁴⁶Sm, ¹⁴⁸Gd, ¹⁵⁰Gd, ¹⁵⁴Dy) into overall toxicity of spallation targets.     

A quantum full adder for a scalable nuclear spin quantum computer

We demonstrate a strategy for implementation a quantum full adder in a spin chain quantum computer. As an example, we simulate a quantum full adder in a chain containing 201 spins. Our simulations also demonstrate how one can minimize errors generated by non-resonant effects.     

Optimal and Admissible Programs of Credit Control

The study of optimal credit policy of a developing enterprise was continued with the aim of establishing and analyzing the finite formulas for the final boundary problem of the maximum-principle procedure. Advisability of the pulse crediting as opposed to the continuous crediting and no-credit development, as well as the advantages of the optimal relay payment of debt as compared with the admissible uniform payment were estimated from the point of view of enterprise. The qualitative features stemming from the nonlinearity of the enterprise production function were discussed. Considerations on managing credits in an unstable economic environment were presented.     

Determination of cycle nonproportionality coefficient

We propose a cycle nonproportionality coefficient for a broad class of complex cyclic paths, allowing us to establish a clear relationship between the geometry of the strain path and the maximum hardening level attainable in the material in the steady state for a fixed value of the maximum plastic or total strain range. We discuss the effectiveness of using the proposed cycle nonproportionality coefficient compared with analogous parameters familiar from the literature. Based on a previously developed version of the endochronic theory of plasticity, we have numerically modeled the behavior of a material for cyclic loading along different planar nonproportional paths.Translated from Problemy Prochnosti, Nos. 5–6, pp. 29–38, May–June, 1995.     

Use of Shears with a “Rolling Cut”

This article examines the advantages and disadvantages of using guillotine shears with an inclined top blade for the cross-cutting of flat-rolled products on modern plate mills. It is shown that it is necessary to use shears of an improved design. After shears with a “rolling cut,” designed by the All-Russia Scientific Research, Planning, and Design Institute of Metallurgical Machinery (VNIImetmash), were installed in the line of the 2800 plate mill at the Ural Steel combine, the institute conducted studies to optimize the parameters of the cutting operation and developed recommendations for the shears operators on how to adjust the shears to obtain a quality cut edge on the plates.     

Use of sensitivity functions in the problem of designing a multilayer heat shield

An approach is proposed for solving the problem of designing a multilayer heat shield with a prescribed structure from the restrictions on its temperature.Tanslated from Inzhenerno-Fizicheskii Zhurnal, Vol. 61, No. 6, pp. 1014–1018, December, 1991.     

M. Yu. Bal'shin, A Founder in the Science of Powder Consolidation

The collection of analytical and experimental data makes it possible to consider the existence of three common scientific principles for solid body consolidation to be proved. One of them, the identity principle, formulates the degree of generality between properties and the behavior of a porous, consolidating or consolidated body, and a normal body; two others, i.e. the principle of self-regulation and the transmission principle, formulate features of the properties and behavior of powder bodies. The identity principle may be formulated as follows. The properties and behavior of any compact element of a porous body are the same as for the substance of a compact pore-free body with the condition of an identical chemical composition, degree of strain hardening, and test conditions. The self-regulation principle may be formulated as follows. During consolidation there are processes of non-self-regulation (intraparticle, consolidating, increasing and fixing the contacts and equilibrium) loading deformation and self-regulating (intraparticle, deconsolidating, reducing and breaking contacts and body equilibrium) unloading deformation; non-self-regulation consolidating deformation increases, and self-regulation deconsolidating deformation reduces compaction resistance; flow of particles substance is intermediate in nature between entirely continuous and entirely localized flow in contact areas. The greater the degree of consolidation, the lower is the level of self-regulation for its processes. The transmission principle may be formulated as follows. Consolidating stresses applied to a consolidating self-regulating body are transmitted by their elastic balancing in a continuous critical zone lying entirely within the solid phase of a body with equally large interparticle (contact) and intraparticle (critical) sections normal to the loading direction. These stresses and elastic loading are only transmitted through fixed, and not through broken, contact sections at this instant of consolidation, and consequently through fixed critical sections in a fixed critical zone.     

Synthesis and Study of Magnesium and Calcium Uranogermanates

Previously unknown alkaline-earth metal uranogermanates of the general formula MII[HGeUO₆]₂·nH₂O (MII = Mg, Ca) were prepared in the form of higher and intermediate hydrates and anhydrous compounds. The compounds were studied by X-ray diffraction, IR spectroscopy, and thermal analysis.