Pressing nozzles for high-speed steel teeming

Conclusions The Magnezit Combine has begun production of unfired pressed steel-teeming nozzles, with a channel diameter of 120 mm and height of 400 and 450 mm, made of magnesite paste.These nozzles have been put into service and adopted for high-speed top teeming of steel from a 330 ton ladle in the open-hearth shop of the KMW.Translated from Ogneupory, No. 1, pp. 23–26, January, 1979.     

Magnesia products from powders containing more than 94% MgO

Conclusions Using magnesite powders with large contents of magnesium oxide we obtained high-quality magnesite and periclase-spinel products. Periclase-spinel products obtained from the above powders satisfy the requirements of GOST for the PShSP type of product for the roofs of open-hearth furnaces and electric steel furnaces. Their thermal shock resistance is 7–15 water-heat cycles, compared with 5–7 heat cycles for ordinary periclase-spinel products, which is due to their structural features.Translated from Ogneupory, No. 1, pp. 54–58, January, 1969.     

Psychosocial elements in the work environment of a large call center operation

The author investigates psychosocial factors that prevent early detection of injuries and the effect of late reporting on the long-term health of workers.     

Structure of glasses and melts in the Na<Subscript>2</Subscript>O-B<Subscript>2</Subscript>O<Subscript>3</Subscript> system from high-temperature Raman spectroscopic data: I. Influence of temperature on the local structure of glasses and melts

The local structure of glasses and melts in the Na₂O-B₂O₃ system in the composition range 10–30 mol % Na₂O is investigated by high-temperature Raman spectroscopy in the temperature range 20–1150°C. The recorded spectra are analyzed by simulating the experimental spectra in the form of a superposition of the set of Gaussian lines. The results of the simulation are used to determine the concentrations of the main structural units of borates as a function of the composition and temperature. The dynamic equilibrium of the interaction between the structural units in melts has the form

$B_{4/2}^ - \rightleftarrows B_{2/2} O^ - $

and shifts toward the right, i.e., toward the formation of BØ₂O^? metaborate triangles (where Ø is a bridging oxygen atom), with an increase in temperature. The enthalpy of the disproportionation process depends on the melt composition and increases with an increase in the oxide modifier concentration.

     

Chloramphenicol-induced amnesia for passive avoidance training in the day-old chick

In all, 56 triads of same-sex 3rd-, 4th-, and 5th-grade children were observed during an intimate discussion, a cooperative puzzle task, a competitive game, and free play. Observers coded triadic interaction using a Q sort and individual process ratings. Of particular interest was how gender and the pattern of friendship ties among group members related to children's behavior. Triads of girls were more intimate, exchanged more information, and were less aggressive than were triads of boys. Analyses of within-gender variability revealed 2 prototypical types of triads among boys but only 1 among girls. Girls and boys expressed similar attitudes toward triadic interaction in postsession interviews. However, girls', but not boys', attitudes were closely linked to the quality of interactions during the session. For both sexes, interaction was not strongly influenced by the initial configuration of friendship ties among triad members.     

Coordination state of aluminum and boron in barium aluminoborate glass

This paper considers the coordination state of boron and aluminum ions in barium aluminoborate glass with a constant ratio of BaO: B₂O₃ = 0.5 and a variable ratio of Al₂O₃: BaO = 0–3. The dependence of the concentrations of boron and aluminum atoms with a variable coordination number on the Al₂O₃ content was estimated by IR, ¹¹B and ²⁷Al NMR spectroscopy. The nonlinear nature of the obtained dependences was attributed to variations in the aluminum oxide properties. At a content of less than 30 mol % Al₂O₃ serves primarily as a network former, while an increase in the Al₂O₃ concentration results in its higher modifying role in the studied glass.     

Structure of high-alkali melts in the lithium borate system from vibrational spectroscopic data

Melts of the compositions Li₂O · B₂O₃, 3Li₂O · 2B₂O₃, 2Li₂O · B₂O₃, and 3Li₂O · B₂O₃ (asbatched) are investigated using high-temperature Raman spectroscopy in the temperature range 973–1373 K. The IR and Raman spectra of polycrystalline samples of the corresponding compositions are measured. The Raman spectra of the melts and the products of their crystallization are compared, and the frequencies of characteristic vibrations of the structural units are determined. The regularities of the changes in the structure of the melts are established as a function of the composition and temperature.     

In situ measurements of optical parameters in Lake Baikal with the help of a Neutrino telescope

We present results of an experiment performed in Lake Baikal at a depth of approximately 1 km. The photomultipliers of an underwater neutrino telescope under construction at this site were illuminated by a distant laser. The experiment not only provided a useful cross-check of the time calibration of the detector but also allowed us to determine inherent optical parameters of the water in a way that was complementary to standard methods. In 1997 we measured an absorption length of 22 m and an asymptotic attenuation length of 18 m. The effective scattering length was measured as 480 m. By use of (cos theta) = 0.95 (0.90) for the average scattering angle, this length corresponds to a geometric scattering length of 24 (48) m.     

Evaluation of two dextrose-based directly compressible excipients

The objectives of this research were to evaluate the physical properties and compaction behavior of two dextrose-based directly compressed excipients. Anhydrous theophylline (10% w/w) was used as a drug model, Emdex and or Maltrin M510 (89.5% w/w) were used as diluent, and magnesium stearate (0.5% w/w) was used as lubricant. Direct compression and wet granulation methods were used for preparing the compacts. In general, the wet granulation method reduced the density of the mixture and consequently its flow rate compared to the mixture prepared only by solid-solid mixing. All formulations were compressed at four different compressional forces and at a target weight of 450 mg +/- 5%. Tablets obtained were different in physical properties and mechanical strength based on type of excipient used and methods of tablet preparation (direct compression versus wet granulation). Compacts prepared from Maltrin M510 had a longer disintegration time and slower drug release than compacts of the same composition but prepared with Emdex. Disintegration time and drug dissolution from tablets containing Maltrin M510 as diluent and prepared by wet granulation appeared to be controlled by a "gel" layer formation around the tablets and not by the tablets porosity. This study demonstrates that full characterization of excipients is needed because a different manufacturing process for the same excipients may produce differences in the pharmaceutical products.