An alternative formulation of the geometric stiffness matrix for plate elements

A simplified formulation of the geometric stiffness matrix for plate elements is presented. In this formulation the transverse displacement is defined along the element boundary but not for the element interior as with the usual formulation. As such the formulation is particularly suitable for use with hybrid stress or discrete Kirchhoff methods which are also based on boundary approximation of the transverse displacement.

The simplicity, computational economy and accuracy obtained with the formulation compare favorably with the usual order formulation.     

Flux Jumps and H-T Diagram of Instability for MgB2

We present a study of magneto-thermal instabilities in polycrystalline MgB₂ superconductor, by magnetic hysteresis loop measurements and by investigations of magnetic flux dynamics with a miniature Hall probe. Temperature and magnetic field ranges where the flux jumps may be observed have been determined. On the basis of measurements of the magnetic flux dynamics, an average magnetic diffusivity describing the process of the flux jump is estimated. This parameter is compared with the thermal and magnetic diffusivities calculated on the basis of available data for thermal conductivity, heat capacity and resistivity. It is shown that the estimated value of the field of the first flux jump is influenced significantly by the field dependence of specific heat. In order to explain the observed phenomenon, the temperature reached by the sample during the flux jump at different magnetic fields is calculated.     

Surface-tension-induced interfacial convection and its effect on rates of mass transfer

Surface-tension-induced interfacial convection (Marangoni phenomena) can appear as a result of mass and heat transfer, compression and dilatation of surface films or their non-Newtonian behaviour and owing to presence in the interface of electrostatic charges. In process engineering problems the mass transfer effect is usually predominant and, depending on the geometry of the system, leads to surface renewal or changes in interfacial area. The surface renewal phenomena can appear as instabilities or disturbances and their effect on mass transfer is presented for transfer to and from drops as well as across flat interfaces in stirred and laminar flow contactors. Mass transfer coefficients and drag coefficients of drops are compared under conditions of undisturbed (diffusional) transfer, cellular convection and interfacial turbulence for stable and unstable direction of transfer. The importance of gravitational instability is indicated.     

Thin plate elements with relaxed Kirchhoff constraints

An analysis of thin plates by C⁰ elements is presented. The fundamental part of it is the formulation of a set of constraints that relate the rotational degrees of freedom to the translational degrees of freedom and which are weaker than the usual Kirchhoff constraints. A penalty term associated with these constraints is then introduced instead of the usual expression for the shear strain energy. It is shown that the approach is effective for both quadrilateral and triangular elements.     

Review of Psychology: The unity of human behavior.

Reviews the book "Psychology: The unity of human behavior," by Timothy J. Gannon (see record 1954-06735-000). This volume is an introductory textbook of psychology for college students. In addition to a somewhat different organization of the material and a different emphasis accorded to various topics Gannon's book introduces certain theoretical considerations which are not ordinarily found in most textbooks. The book is divided into four parts: The first part, the shortest, is a general introduction. The second, entitled "Reception," deals with sensation and perception. The author, in discussing perception, particularly stresses the neural correlates of perception and the localization of functions in the brain. The third, "Response," contains the discussion of reflexes, drives, and emotions. The fourth and last part, "Integration," is the longest, constituting almost half of the book. The principal concern of the author is to present all experiences, and all behavior, as integrated manifestations of a single living person. The entire book is characterized by an effort to present to the student not merely a survey of psychological problems and known facts about man but to provide him at the same time with a concept of man's nature which would serve as a key to the understanding of man as such. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cyclization in chain-crosslinking copolymerization

Summary Styrene and ethylene dimethacrylate were polymerized in benzene solutions to high conversions. Gels were prepared from critical concentrations of the divinylidene monomer and the fractions of the divinylidene units engaged in intermolecular crosslinks were estimated. The fractions were found to be very small, viz. 5, 10 and 18 % at the total monomer concentrations 1, 2 and 3 mol/dm³, respectively. Behaviour of pregel polymers suggests that cyclization of primary chains and multiple crosslinking are responsible for the low efficiency of the crosslinking agent.Presented at the 7th IUPAC Discussion Conference Polymer Networks, Karlovy Vary, CSSR, September 15–19, 1980     

Circulating fluid-bed reactor for coal pyrolysis

A high temperature coal pyrolysis reactor was developed and its operation demonstrated on a scale of 8 t/h. Pyrolysis is performed in a circulating fluidized bed reactor at 850–950°C. The developed process was integrated into smokeless fuel production technology and tested. Experimental data and reactor performance are presented.     

Effect of phosphine on acid corrosion of iron

The effect of the phosphine-concentration (10^?8–10^?3 M) in strong acid solutions (pH = 0) on the corrosion rate of pure iron and Fe- 0.12% P alloy has been investigated. It was shown that at low concentrations (10^?7–10^?6M), phosphine accelerates the corrosion of iron, whereas at adequately high concentrations (10^?5–10^?3 M) it has inhibitory properties. In the presence of PH₃ the cathodic reduction of hydrogen ions is strongly accelerated. At the same time, the increase in PH₃ concentration causes an increase of surface coverage by PH₃ molecules, which results in the inhibition of both partial electrode processes.     

The thermal behaviour of lignins modified by chlorophosphazenes

The thermal behaviour in air of lignins modified by chlorophosphazenes as well as that of the raw materials of lignins has been investigated using thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA). The thermogravimetry and derivative thermogravimetry studies of lignins modified by chlorophosphazenes have shown their thermal resistance to be relatively higher than that of the intital raw materials of lignins in concrete kraft lignin and sodium ligninosulfonate. The differential thermal studies have demonstrated that the thermal degradation of products investigated takes place via exothermic processes. The lignins modified by chlorophosphazenes have been shown to be thermal and flame-resistant materials.