Synthesis of CN<Subscript>x</Subscript> nanotubes using catalysts prepared from zinc and nickel bimaleates

Nitrogen-containing carbon nanotubes have been prepared via acetonitrile (CH₃CN) pyrolysis at 850°C catalyzed by nanoparticles produced by the thermal decomposition of zinc and nickel bimaleates and their solid solutions. The synthesized samples have been characterized by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. The results demonstrate that increasing the zinc content of catalyst nanoparticles reduces the yield of carbon nanotubes and increases the nitrogen content of the material. The high synthesis temperature gives rise to zinc vaporization, which influences the growth process, increasing the nanotube diameter, reducing the wall thickness, and lowering the structural perfection of the graphite layers.     

Investigation of the influence of design parameters on the flow performance of single and double disk viscous micropumps

This paper investigates the effect of radius ratio, and channel aspect ratio on the flow performance of newly introduced single and double disk viscous micropumps. A lubrication solution for the flow field, which accounts for both radius and channel aspect ratios either in single or double disk micropumps was developed and compared with available experimental data and with an approximate solution which estimates for the flow rate only in single disk pump and neglects channel aspect ratio. Additionally, a number of 3D numerical models for single and double disk micropumps were built and analyzed using the finite volume method. Pressure and drag shape factors were introduced to describe the effects of radius and channel aspect ratios on the flow rate. The values of these factors for the whole range of studied parameters are found analytically and numerically. The error in estimating the flow rate was found to be less than 10% for r ₁ /r ₂ > 0.2, and less than 7% for the studied range of h/w. Also, the lubrication solution was found to be in good agreement with the numerical and experimental results.     

Mass transfer in a rotor dispersion-film apparatus

Results of experimental investigations of the desorption of carbon dioxide from water in a rotor dispersion-film apparatus are presented. The main factors influencing the volume mass-transfer coefficient in the liquid phase and the efficiency of mass transfer in this apparatus were determined. A comparative analysis of the apparatus investigated with other analogous apparatus has been carried out. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 144–148, March–April, 2007.     

Multifrequency gyrotron with high-efficiency synthesized waveguide converter

The results of numerical simulation and experimental investigation of a prototype of a megawatt multifrequency gyrotron for controlled thermonuclear fusion facilities are presented. In experiments, the gyrotron has operated at six frequencies in the range 105–152 GHz with small diffraction losses in the internal quasi-optical system and a high Gaussian mode content in the output beam.     

Buckling of Columns with Intermediate Elastic Restraint

This paper presents a comprehensive set of exact stability criteria for Euler columns with an intermediate elastic restraint. A subset of this class of problem is the buckling problem of columns with an intermediate rigid support where the elastic restraint takes on an infinite stiffness. Also, this study reiterates the existence of a critical elastic restraint stiffness in which the buckled mode switches to a higher-buckling mode of the corresponding column without an intermediate support. It is clear that this critical stiffness value exists only when the restraint is placed at the node of the higher-buckling mode and the buckling load associated with this critical stiffness value is the maximum achievable value that can be attained with an intermediate elastic restraint.     

"The association between emotional upset and cardiac arrhythmia during daily life": Correction to Carels et al. (2003).

Reports an error in the original article by R. A. Carels et al (Journal of Consulting & Clinical Psychology, 2003[Jun], Vol 71[3], 613-618). On page 615, Lines 18, 20, 22, of Table 1, the data in the rows that read "Tachycardia in min per hr," "Repetitive PVCs per hr," and "PVCs per hr" are incorrectly reported in the n and % columns. They should have been reported in the M and SD columns. The corrected table is provided. (The following abstract of this article originally appeared in record 2003-00756-023.) Ventricular arrhythmia exhibits considerable within-subject variability that cannot be attributed to clinical status alone. This investigation examined the extent to which cardiac arrhythmia was associated with psychological and physical factors assessed during the hour preceding arrhythmic or nonarrhythmic activity. Approximately twice hourly, 46 patients randomly completed a diary assessing mood and physical symptoms during 24-hr electrocardiographic monitoring. Greater negative emotion was associated with increased arrhythmia. Additionally, greater negative emotion was significantly associated with increased arrhythmia among participants in a low left ventricular ejection fraction group (LVEF). However, this relationship between negative emotion and arrhythmia was not... (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of the composition of phosphorus-containing raw materials on glass formation in the Li2O-Li2SO4-P2O5 system

Calculation and experimental methods showed that the use of lithium metaphosphate for making up batches of Li₂O-Li₂SO₄-P₂O₅ multilithium glass systems reduces the founding temperature-time parameters while simultaneously increasing the homogeneity of the melts.