Models and phenomenology

It is evident that models of the knee should match the observational phenomenology. In this talk I discuss a few aspects of phenomenology, which are important not only for the understanding of the knee origin, but also for the general problem of the origin of cosmic rays. Among them are the shape of the energy spectrum, its irregularity, the sharpness of the knee and its fine structure. The classification of models is given and some examples of the most recent models are discussed. The most probable conclusion deduced from this examination is that the knee has an astrophysical origin and the so called 'source' models of the knee are most likely among them.Comment: 13 pages, 4 figures, overview talk at 19th European Cosmic Ray Symposium, Firenze, Italy, 30.08-4.09.2004 (to be published in the Int.J.Mod.Phys.A

Improvement of the homogeneity of magnetic field by the attenuation of a selected component with an open superconducting shield made of commercial tapes

Homogeneous magnetic fields are needed in many applications. The resolution of medical imaging techniques depends on the quality of the magnetic field, as does the efficiency of electron cooling systems used at particle accelerators. Current methods of improving homogeneity require complex arrangements of magnet windings. In this work, the application of commercial superconducting tapes for this purpose is analyzed experimentally and numerically. The shielding effect exhibited by the superconductors can be used to control the shape of the magnetic field. An open magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. To form a shield, the superconducting tapes are wound on a former. Then, it is positioned coaxially inside an electromagnet. The measurements are performed in the DC magnetic field and at zero-field cooling conditions. A numerical model is developed to further analyze the magnetic field. New simplifications and proper constraints allow the use of an axial symmetry despite relatively complex geometry of the shields. Results from the simplified model and obtained experimentally are consistent. The decrease of radial component of the magnetic field and the significant improvement of its homogeneity are observed in a shielded region. The decrease of shielding quality with the increase of an applied magnetic field is observed. Empirical formulas describing the dependence of shielding quality on the geometry and the critical current of the shield are developed

NN Interaction JISP16: Current Status and Prospect

We discuss realistic nonlocal NN interactions of a new type - J-matrix Inverse Scattering Potential (JISP). In an ab exitu approach, these interactions are fitted to not only two-nucleon data (NN scattering data and deuteron properties) but also to the properties of light nuclei without referring to three-nucleon forces. We discuss recent progress with the ab initio No-core Shell Model (NCSM) approach and respective progress in developing ab exitu JISP-type NN-interactions together with plans of their forthcoming improvements.Comment: 9 pages, 3 figures, to be published in Proceedings of Few-body 19 conferenc

Developing technological process of obtaining giality casts

The article considers the process of manufacturing castings using sand-resin forms and alloying furnace. Were the optimal technological parameters of manufacturing shell molds for the manufacture of castings of heating equipment. Using the same upon receipt of castings by casting in shell molds furnace alloying and deoxidation of the metal will provide consumers with quality products and have a positive impact on the economy in general engineering

Conducting and automating the water Morris maze test in SPF conditions

The water Morris maze is the basic test to study the spatial ability to learn as well as spatial memory in laboratory rodents. It is a part of a series of tests necessary for behavioral phenotyping of mutant and transgenic mice. At the same time, conducting this test in SPF conditions must comply with very strict regulations concerning pathogen control. A white animal on the surface of whitened water is low contrast and this does not allow the animal to be traced automatically, which represents yet another major problem. A unique installation based on EthoStudio has been developed at the Institute of Cytology and Genetics SB RAS and the Institute of Automation and Electrometry SB RAS. This installation automates the process of tracing mice of any coat color in SPF conditions. This includes a setup to install a plastic water reservoir (110×40 cm), a digital camera and a light source. Water to fill the reservoir was sterilized using a Van Erp Blue Lagoon UV-C Tech 15000 ultraviolet decontaminator. The image of an animal was processed in a frame-by-frame fashion using the EthoStudio program, with the following parameters calculated: latent release time, route covered, cumulative distance to the platform and the time spent in the reservoir sectors. With this installation, we were able to study the spatial ability to learn and spatial memory in mice of the C57BL/6 strain and in mice of the C57BL/6/ Kaiso strain developed on the C57BL/6 background, with the gene encoding the methyl-DNA binding Kaiso protein knocked-out. It has been demonstrated that mice of these strains are able to learn to find the platform in the water Morris maze and have the location of the platform in their memory for at least the next four days

Radiogenic Lead with Dominant Content of 208 Pb: New Coolant and Neutron Moderator for Innovative Nuclear Facilities

As a rule materials of small atomic weight (light and heavy water, graphite, and so on) are used as neutron moderators and reflectors. A new very heavy atomic weight moderator is proposed-radiogenic lead consisting mainly of isotope 208 Pb. It is characterized by extremely low neutron radiative capture cross-section (0.23 mbarn for thermal neutrons, i.e., less than that for graphite and deuterium) and highest albedo of thermal neutrons. It is evaluated that the use of radiogenic lead makes it possible to slow down the chain fission reaction on prompt neutrons in a fast reactor. This can increase safety of the fast reactors and reduce as well requirements pertaining to the fuel fabrication technology. Radiogenic lead with high 208 Pb content as a liquid-metal coolant of fast reactors helps to achieve a favorable (negative) reactivity coefficient on coolant temperature. It is noteworthy that radiogenic lead with high 208 Pb content may be extracted from thorium (as well as thorium-uranium) ores without isotope separation. This has been confirmed experimentally by the investigations performed at San Paulo University, Brazil

Using high-chromium iron as material for production of the equipping components of mine shafts

This paper deals with service conditions of shaft equipment, in particular, inserts of sliding bearings for the purpose of increasing service life due to material substitution and wear resistance increase. As a new material high-chromium irons are offered. Studies are conducted on a microstructure and wear resistance of prototypes is measured. Experimental data are treated by methods of mathematical statistics which confirm reliability of results. The results obtained make it possible to suggest using high-chromium irons as the direct material to produce inserts of sliding bearings