Spheroidization of medium-carbon steels

Spheroidization experiments were made on a medium- carbon AISI 4037 steel, using both intercritical and subcritical annealing cycles. The results indicate that in the subcritical cycle the spheroidization occurred much more quickly than expected, so that shorter times were sufficient to achieve high formability. On the other hand, the hardness dropped faster in the intercritical cycle. Although more work needs to be done, these results suggest that using a subcritical spheroidization process instead of an intercritical process could achieve considerable savings in time, energy, and cost.     

Structure formation in production of yttrium-silicate materials by the sol-gel method

Materials made from yttrium silicates were synthesized by the sol-gel method. The effect of the amount of yttrium oxide, which varied from 10 to 50% (molar content), and the water:alcoholate molar ratio was investigated. Structure formation and the character of crystallization of gels in heat treatment in the 650–1300°C range were investigated. __________ Translated from Steklo i Keramika, No. 1, pp. 3–6, January, 2007.     

Dichotomous indexing of array in recursive construction of voxel-graphic images

Rapid development of the cluster multiprocessor computer systems allows one to pose to the designers of the computer-graphical systems the problem of organization of graphical information enabling efficient use of the parallel algorithms. Consideration was given to the use of the dichotomous principle of binary construction of a numerical sequence for successive indexing of the elements of a multidimensional array in the problems of recursive decomposition of the multidimensional space. This principle was used to advantage in recursive construction of the voxel graphical information used in the program accelerators of graphical processing based on parallelization of the algorithm and partial sorting of the graphical output flow in terms of the recursion depth.     

Solving a maximin location problem on the plane with given accuracy

We consider the optimal placement problem in a bounded region on a plane with fixed objects. We specify minimal admissible distances between placed and fixed objects. The optimization criterion is to maximize the minimal weighted distances from placed objects to fixed ones. We propose a quasipolynomial combinatorial algorithm to solve this problem with a given accuracy. We show the results of a computational experiment with the integer programming model and the IBM ILOG CPLEX suite.     

3D SLAM from stereoimages

A method of visual navigation by stereoimages for autonomous underwater vehicles is suggested. Two modifications of the method are considered. The first one is based on integration of measurement data of onboard navigation system with visual data. The second modification relies on the use of a six-cloud computation scheme. Results of computational experiments with model data are presented.     

Interactional Order and Constructed Ways of Seeing with Touchless Imaging Systems in Surgery

While surgical practices are increasingly reliant on a range of digital imaging technologies, the ability for clinicians to interact and manipulate these digital representations in the operating theatre using traditional touch based interaction devices is constrained by the need to maintain sterility. To overcome these concerns with sterility, a number of researchers are have been developing ways of enabling interaction in the operating theatre using touchless interaction techniques such as gesture and voice to allow clinicians control of the systems. While there have been important technical strides in the area, there has been little in the way of understanding the use of these touchless systems in practice. With this in mind we present a touchless system developed for use during vascular surgery. We deployed the system in the endovascular suite of a large hospital for use in the context of real procedures. We present findings from a study of the system in use focusing on how, with touchless interaction, the visual resources were embedded and made meaningful in the collaborative practices of surgery. In particular we discuss the importance of direct and dynamic control of the images by the clinicians in the context of talk and in the context of other artefact use as well as the work performed by members of the clinical team to make themselves sensable by the system. We discuss the broader implications of these findings for how we think about the design, evaluation and use of these systems.     

Magnetic properties of iron nanoparticles alloyed with cobalt

Nanoparticles in the iron-cobalt system with an average size ranging from 8 to 30 nm were prepared by the gaseous-phase synthesis. Iron and cobalt carbonyls were used as starting precursors. The nanoparticles were synthesized through codecomposition of iron and cobalt carbonyl vapors in the flow of an inert gas in a flow-type reactor. The cobalt content was varied in the range 0–52 wt % with independent control of the evaporation rate of the starting precursors. The magnetic hysteresis characteristics of the nanoparticles as functions of the particle size and the cobalt content were examined by vibrating-sample magnetometry.     

SHS of mineral-like ceramics for immobilization of radioactive nuclear wastes

Synthetic analogs of titanate ceramics (perovskite and zirconolite) designed for use as a matrix for immobilization of high-level nuclear fuel reprocessing wastes (HLW). Such ceramics have been prepared by SHS method from a mixture of titanate ceramics and non-radioactive model oxides. Synthesis conditions have been optimized. The synthesized low-porosity cylindrical compacts exhibited a high strength and low rate for leaching Cs, Sr, Y, Ce, and La in bidistilled water. The phase composition and microstructure of synthesized products have been characterized. The immobilization of Cs was found to be accompanied by a marked loss of this element. The text was submitted by the authors in English.     

Mössbauer investigation of the europium state in fluoride glasses

The structure of glasses based on fluorides of alkaline-earth metals, aluminum, and europium, in which aluminum fluoride is partially replaced by aluminum nitride, is investigated by ¹⁵¹Eu Mössbauer spectroscopy. It is found that these glasses contain europium atoms in two oxidation states (+2 and +3). The isomer shifts of the Mössbauer spectra of Eu³⁺ and Eu²⁺ ions entering into the composition of the fluoride glasses are somewhat different from the isomer shifts of the Mössbauer spectra of EuF₃ and EuF₂ compounds. This difference is explained by the effect of the alkaline-earth metal and aluminum atoms (not bound directly to the europium atoms) on the electron density at the ¹⁵¹Eu nuclei. The broadening of the Mössbauer spectra of the Eu²⁺ ions in the fluoride glasses is explained by the nonuniform isomer shift.