Low-temperature magnetostriction and distortions in the rare-earth Laves phases

The effects of partial substitution of dysprosium in Tb0.2Dy0.8Co2 by terbium and gadolinium on the structure and magnetic properties have been studied. Two compositions, Tb0.3Dy0.7Co2 and Tb0.2Dy0.7Gd0.1Co2 have been synthesized. Their crystal structure, in contrast to the structure of the original compound, has both tetragonal distortions and rhombohedral distortions at lower temperatures. Anomalies of magnetostriction and magnetocaloric effect near the observed magnetic phase transitions have been studied. The sign-alternating temperature dependences of the longitudinal and transverse magnetostrictions associated with various types of crystal structure distortions of the alloys are revealed

Extraction processing of concentrated solutions of uranyl nitrate with high impurities content

Process flowsheet of recycling uranium concentrated solutions with its purification from insoluble impurities of iron, silicon, molybdenum, calcium oxides and hydroxides and soluble impurities with application of centrifugal extractors cascade has been developed and suggested for commercial introduction. The process was carried out at extractant saturation (30 % tributyl phosphate in hydrocarbon diluent) in extraction assembly lower than a limiting level (85...95 g/l) and in wash assembly - at limiting saturation (up to 120 g/l). As a result the waste uranium content in water-tail solutions 0,01...0,04 g/l and minimal content of impurities in re-extractors is provide

Effect of additions of zinc stearate on the properties of sintered Nd-Fe-B magnets

Zinc stearate additions have been used to increase the remanence of sintered Nd-Fe-B magnets produced by the powder metallurgy without powder pressing. Zinc stearate acts as an internal lubricant, i.e., it decreases the friction forces between the particles and favors an increase in the degree of texture of the powders, which is induced by the magnetic field. It is shown that the density and the magnetic hysteresis characteristics of sintered magnets produced using additions of 0.15 wt % zinc stearate exceeds the corresponding values obtained for magnets produced without this addition at a filling density of powders in containers of more than 2.9 and 3.0 g/cm3 in dry and wet states, respectively. Using additions of zinc stearate in the amount of 0.15% with respect to the weight of the powder, magnets with a density of 7.55 g/cm3, B r = 14.02 kG, H c = 7.91 kOe, and (BH)max = 46.1 MG Oe have been produced. © 2013 Pleiades Publishing, Ltd

A CLUSTERING APPROACH IN THE UrQMD TRANSPORT MODEL FOR NUCLEAR COLLISIONS AT RELATIVISTIC ENERGIES

A method for cluster recognition from nucleon distributions generated in calculations of relativistic collisions of light particles (protons, α-particles) with nuclei in the framework of the UrQMD model is proposed. The excitation energy of the clusters which is necessary to take into account for the de-excitation of the calculated fragments was estimated from empirical considerations. The approach was applied to calculate mass distributions of fragments in p + Fe collisions for different proton energies and showed a good correspondence to experimental results. The software implementation of the clustering method and a visualization of cluster formation substantially facilitate applications of the proposed method

THE EFFECT OF NATURAL XANTHONES AND THEIR MODIFIED DERIVATIVES ON THE CHOLERETIC REACTION IN WHITE RATS

In experiments on white rats choleretic activity of l-hydroxy-2,3,5-trimethoxyxanthone and 1-hydroxy-2,3,4,5-tetramethoxyxanthone was determined. Their alliloxy- and. acetoxy-derivatives are more effective that native substances

Projectile fragmentation at Fermi energies with transport simulations

Projectile fragmentation at Fermi energies is an important method to produce radioactive beams for the study of isospin asymmetric nuclear matter. Fragmentation is usually parametrized successfully by empirical phase space models. In this contribution we apply a microscopical method, semiclassical transport theory, to study in detail the reaction mechanism of the fragmentation process. We apply it to experimental data of 18O on 181Ta at E/A = 35 MeV measured in Dubna. We calculate consistently the excitation energy of the primary fragments and take into account their decay by a statistical model. It is found that the dissipative part of the fragment spectra is well described by transport theory. However, there are in addition important direct and collective contributions

TREATMENT OF INSUFFICIENT JOINT EXTENSOR MECHANISM IN PRIMARY AND REVISION KNEE REPLACEMENT

Insufficiency  of the  knee  joint  extensor  mechanism  is the  absolute  contraindication for total  knee  arthroplasty. Therefore, it is necessary to restore the extensor  mechanism before arthroplasty or to change the treatment approach.Purpose of the study  – to evaluate  the  outcomes  of surgical  reconstruction of the  knee joint  extensor  mechanism during primary or revision knee arthroplasty.Materials and methods. 25 reconstructions of extensor  mechanisms  (24 patients) were performed  in the period from 2006 to 2015. Five procedures out of 25 were performed in primary TKA and 20 in revision TKA. Indications for extensor mechanism  reconstruction were as follows: patellar  tendon  rupture in 15 cases (60,0%),  fracture  of patella  in 5 cases (20,0%), quadriceps tendon  rupture in 3 cases (12,0%) and other indications in 2 cases (8,0%). One of the following four techniques was used to restore  the extensor  mechanism: “Frame / Loop” allograft of patellar  tendon  in 6 cases (24,0%); bone – patellar  tendon  – bone allograft in 9 cases (36,0%); quadriceps tendon  – patella-patellar tendon  – bone allografts in 7 cases (28,0%); weber’s internal fixation of patella in 3 cases (12,0%).Results.  All patients were  evaluated based  on  clinical  examination,  KSS  and  WOMAC  scores  (18  patients), and standard x-rays (13 patients). The mean follow-up  period  in the  present  study  was 44 months  postoperatively. Reconstruction of the knee joint extensor  mechanism  resulted  in a significant  reduction of pain in 38.8% of patients, the knee stability was restored  in 83,3% of patients and the active  knee extension  improved  significantly  in the vast majority  of patients.Conclusion. Despite  the  objective  improvement of the  knee  joint  function  after  the  reconstructions of extensor mechanism,  the  KSS and WOMAC evaluation scores remained  low which  should  be taken  into  consideration during preoperative planning

Excitons in type-II quantum dots: Finite offsets

Quantum size effects for an exciton attached to a spherical quantum dot are calculated by a variational approach. The band line-ups are assumed to be type-II with finite offsets. The dependence of the exciton binding energy upon the dot radius and the offsets is studied for different sets of electron and hole effective masses

The research of uranium monoxide-oxide dissolution process in nitric acid

The kinetics of concentrates of uranium monoxide-oxide dissolution process by nitric acid solutions of 5...9 mole/l in the range of 11...90 °C has been studied. It is stated that initial nitric acid concentration increasing results in some uranium dissolution degree increasing only at the first process stage. Temperature increasing significantly raises uranium dissolution degree at the first stage as well. Uranium dissolution degree increases for all studied temperatures with increasing of the process period. The main feature of the studied process is that while dissolving uranium monoxide-oxide the behavior of iron, molybdenum, silicon additives is adequate to that of uranium. The equation of the reducing sphere describes the uranium leaching process from its nitric acid concentrate