Test facility for nuclear planetology instruments

An experimental facility for testing and calibrating nuclear planetology instruments has been constructed in partnership between the Space Research Institute (Moscow) and the Joint Institute for Nuclear Research. A model of Martian soil with a size of 3.82 × 3.21 m² and an overall mass of about 30 t is assembled from silicate glass. Glass is chosen in order to imitate absolutely dry soil close in composition to the Martian one. The heterogeneous model allows one to imitate the average elemental composition of Martian soil in the best possible way by adding layers of the necessary materials to it. Near-surface water ice is simulated by polyethylene layers buried at different depths within the glass model. A portable neutron generator is used as the neutron source for testing active neutron and gamma spectrometers. The facility is radiation-hazardous and is thus equipped with interlock and radiation monitoring systems in accordance with the effective regulations.     

Application of Empirical Orthogonal Functions Parameterization in the Problem of Retrieval of the Tropospheric Thermal Structure by Radiometric Data

Radiophysics and Quantum Electronics - We describe the mathematical tools of the optimal estimation method for retrieval of tropospheric temperature profiles (0–10 km) from radiometric data...     

Copolymerization of Acrylamido Sulfonic Acids with Acrylamide and Acrylonitrile in Concentrated Neutral Aqueous Solutions

Copolymerization of alkali metal salts of acrylamido sulfonic acids with acrylamide and acrylonitrile in concentrated aqueous solutions was studied. The influence of the chemical nature, ratio, and physical interactions of monomers on polymerization and on the intrinsic viscosity of the copolymers was examined.     

Quality Control of Cupels and Noble Metal Losses in the Cupellation of Lead Alloys in Fire Assay

Procedures were proposed for the quality control of cupels and noble metal losses in the cupellation of lead alloys. With these procedures, the cost of control operations can be reduced and significant losses of noble metals can be efficiently detected in the course of cupellation.     

Combining X-ray scattering and exafs experiments for studying amorphous alloys of 3d transition metals with zirconium

The atomic structure of the amorphous alloys of several transition metals (Fe, Co, Ni, and Cu) with zirconium is studied in terms of partial paired correlation functions. The short-range order parameters, namely, the shortest interatomic distances, coordination numbers, and the form of distribution functions, are compared and a correlation between the atomic structure and the interaction between atoms of different sorts is established. The study offers the possibility to model the spatial distribution of atoms and the physical properties of the analyzed alloys and predict the properties of new systems. Translated fromZhurnal Struktumoi Khimii, Vol. 39, No. 6, pp. 1025–1030, November–December, 1998.     

On analysis of physical processes on the electrode surface in a rail launcher

This paper analyzes some physical effects that occur on the electrode surface in plasmaarmature rail launchers when the linear current density is higher than critical value. It is shown that under typical experimental conditions, Rayleigh–Taylor and Kelvin–Helmholtz instabilities and magnetohydrodynamic instabilities, which arise from the interaction of the current with the selfmagnetic field, can develop over times much smaller than the launcher operation time and can be responsible for the entry of the electrode material into the discharge. Flash radiography of the electrode surface confirmed the presence of inhomogeneities and ejection of the material from the surface. Under certain conditions, the emergence of conducting metal jets from the electrode surface was detected.     

On the possibility of reducing the penetration capability of shaped-charge jets in a magnetic field

The possibility of reducing the penetration capability of shaped charges by producing a magnetic field ahead of the target with flux lines parallel to the charge axis is considered. The problem is studied on the basis of results of experiments in which a magnetic field was produced in a shaped-charge liner before firing, resulting in a sharp reduction or elimination of penetration. The variation of the magnetic induction in the shaped-charge liner moving in the magnetic field is calculated using the model of two conducting coaxial cylindrical shells corresponding to the charge case and liner and assuming constant induction-current density over the shell thickness. A longitudinal magnetic field is specified on the surface of the outer shell as a function of the spatial distribution of the field ahead of the target and the charge velocity. The magnetic-field intensity that can provide a considerable reduction in the penetration capability of shaped charges of various diameters is estimated. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 112–120, May–June, 2007.     

Estimation of systematic errors at the fluxing stage of fire assay

It was shown that the steps of flux calculation and mixing of sample portion with the flux can be sources of systematic error in fire assay. Errors of analysis due to these operations are evaluated.     

The SANS facility at the Pitesti 14MW TRIGA reactor

The SANS facility existing at the Pitesti 14MW TRIGA reactor is presented. The main characteristics and the preliminary evaluation of the installation performances are given. A monochromatic neutron beam with 1.5 Å ≤ λ ≤ 5 Å is produced by a mechanical velocity selector with helical slots. A fruitful partnership was established between INR Pitesti (Romania) and JINR Dubna (Russia). The first step in this cooperation consists in the manufacturing in Dubna of a battery of gas-filled positional detectors devoted to the SANS instrument.