Spectral sensitivity of the YΦ-4 photographic film in the 0.27–3-keV range

The sensitometric characteristics of a YΦ-4 photographic film were measured in the 0.27–3 keV spectral region. It was ascertained that, as the photon energy decreased from 3.2 to 1.2 keV, the YΦ-4 photographic-film sensitivity remained virtually constant and the abruptly fell. Comparison of the YΦ-4, YΦ-2T and YΦ-P films showed that their sensitivities are functions of the photon energy.     

Modeling the response of monofilament nylon cords with the nonlinear viscoelastic, simplified potential energy clock model

The Simplified Potential Energy Clock Model has been previously shown to predict accurately glassy polymer responses such as yield, creep, enthalpy relaxation, and physical aging. It was now used to predict the behavior of monofilament Nylon fiber. Even though the fibers showed process-induced anisotropy, the simpler isotropic model could be used to describe uniaxial tests. The model predictions again accurately predicted a wide range of Nylon experimental data.     

A versatile approach to develop porous hydrogels with a regular pore distribution and investigation of their physicomechanical properties

Porous polyacrylamide (PAAm) hydrogels with enhanced mechanical properties and regular pore distribution have been synthesized by a unique and facile methodology, which involves formation of the hydrogel pores by leaching out chemically modified silica particles. To improve the pore distribution and mechanical properties of the hydrogel network, porogen particles have been modified with PAAm chains chemically attached to the silica surface. Grafting polymerization initiated by peroxide groups immobilized on the particle surface has been used for this modification. The grafted PAAm layer on the silica surface improves the dispersibility of the porogen material in the hydrogel composition, and simultaneously forms pore “walls” reinforcing the hydrogel network, after leaching out the silica particles. The proposed synthetic way for the development of porous hydrogels includes three steps: (i) tethering of PAAm chains to silica particles due to the grafting polymerization initiated by an adsorbed polyperoxide macroinitiator (PPM), (ii) simultaneous crosslinking of grafted PAAm chains and PAAm forming hydrogel network, and (iii) pore formation by leaching out silica particles in the presence of hydrofluoric acid. The PPM has been synthesized by a free radical copolymerization of the peroxide monomer (PM) N‐(tert‐butylperoxymethyl)acrylamide with acrylamide. Both PM and PPM have been developed in our lab, and applied for the synthesis of porous polymeric hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Structural-morphological features of yarn spun from a polyarylenesulfone oxide-polyamidobenzimidazole mixture

Conclusions -- The structural-morphological features of yarns spun from a mixture of fusible polyarylenesulfone oxide (PASO) and polyamidobenzimidazole (PABI) have been studied.-- It has been shown that in yarn containing from 1 to 15% by wt. of PABI belongs to two-phase disperse systems of the matrix type in which the birefringent PABI phase is dispersed in an isotropic matrix consisting of the fusible PASO component.-- It has been found that in freshly spun PASO-PABI yarn at a weight ratio of 60:40 or 50:50, the PABI retains a high degree of molecular orientation, but the PASO is in a weakly oriented state.VNIIPV, Mytishchi. Translated from Khimicheskie Volokna, No. 3, pp. 14–17, May–June, 1992.     

Numerical simulation of fuel assemblies containing pebble fuel elements

A numerical calculation of the new fuel assembly for a VVER-1000 reactor containing fuel on the basis of pebble fuel elements is carried out. The reactor core pressure drop coefficients in the axial and radial directions are studied.     

Modification of Wiley-Mclaren Tof Analyzers for Laser Desorption

ABSTRACT

Conversion of Wiley-McLaren type TOF instruments for laser desorption is described, including laser optics, timing circuitry, postacceleration detection for high mass and data acquisition. Results are shown to illustrate signal averaging capabilities, detection limits and high mass measurements.     

Application of modern optical methods for detecting the spatial structure of turbulent flames

A number of modern optical methods used for diagnostics of reactive flows are described. Various aspects of using advanced modifications of particle image velocimetry (Stereo-PIV, High-repetition PIV, and Tomo-PIV) for measuring instantaneous velocity fields in reactive flows are discussed in detail. Capabilities of PIV and spectroscopy of flame radiation (CH* radical) in obtaining data on the spatial flow structure and the flame are demonstrated by an example of studying a swirled turbulent propane-air flame and an isothermal jet.