DIFFUSION OF MOISTURE IN DRYING OF SUGAR CANE FIBERS AND BUNDLES

Sugar cane fibers and arrangements of fibers in cylindrical bundles were dried in a thermoanalyzer and their diffusive coefficients were calculated using the slope method. The effect of temperature, moisture content as well as structural changes were analyzed. Diffusion coefficients changed nanlineariy with moisture content and followed an Arrhenius-like functionality with temperature. The analysis of these effects suggested a liquid diffusion transport mechanism of moisture transfer inside sugar cane fibers and bundles.     

Modeling and simulation of non-isothermal catalytic packed bed membrane reactor for H2S decomposition

The recovery of H₂ from H₂S is an economical alternative to the Claus process in petroleum and minerals processing industries. Previous studies [React. Kinet. Catal. Lett. 62 (1997) 55; Catal. Lett. 37 (1996) 167] have demonstrated that catalytic decomposition of H₂S over bimetallic sulfide can proceed at relatively higher rates than over mono-metallic systems due to chemical synergism although conversions are still thermodynamically limited. In the present study, the performance of a catalytic membrane reactor containing a packed bed of Ru–Mo sulfide catalyst has been investigated with a view to improving H₂ yield beyond the equilibrium ceiling. A system of differential equations describing the non-isothermal reactor model has been solved to examine the effect of important hydrodynamic and transport properties on conversion. The results were obtained using a Pt-coated Nb membrane tube as the catalytic reactor enclosed in a quartz shell cylinder. Reynolds number for shell and tube side (Re^s and Re^t) as well as the modified wall Peclet number, Pe_m, dramatically affect H₂S conversions. Membrane reactor conversion rose monotonically with axial distance exceeding the equilibrium conversion by as much as eight times under some conditions.     

A Thermal Study of Polymineral Clays of the Gzhel' Deposit

A thermal analysis of clays of the Gzhel' deposit is performed and their mineral composition is established. The effect of various admixtures and minerals and the dispersity on the behavior of the clays during heating is described.     

Combustion synthesis and tribological properties of SiALON-based ceramic composites

β-Sialon-based composite ceramics with varied BN, TiN, TiB₂, SiC, and ZrO₂ contents were fabricated by infiltration-mediated combustion under high pressure of nitrogen gas. Friction and wear behavior of synthesized composites were explored as a function of their microstructure, phase/elemental composition, density, and pore size distribution.     

Thermal explosion in mechanically activated Ti-Ni powders: Relationship between process parameters and product composition

Upon variation in the duration of mechanical activation, characteristic temperatures of thermal explosion (TE) in Ti-Ni powder mixtures and phase composition of products were explored by electron microscopy, optical metallography, and XRD. The results shed new light on the mechanism of structure formation during TE and on the relationship between process parameters and product composition.     

Heat of combustion of coal: Basic principles and new calculation methods

Stepwise changes in the heat of combustion of Donetsk Basin coal and vitrinites during metamorphism are implied by correlation analysis of a sample including data regarding the composition and properties of bed specimens. On the basis of the relative rates of oxidation processes with the liberation of oxygen-bearing gases and carbon accumulation, as well as the rate of subsequent carbon-ring formation, we note the difference in rate and direction of change in the heat of combustion within three successive intervals: 32–36, 36.3 ± 0.3, and 36–34 MJ/kg. The yield of volatiles may be employed as a predictive parameter in the regression equation for preliminary calculation of the heat of combustion with mean square deviation 0.325 MJ/kg.     

Radioactivity of coal and ash

The radioactivity of Kuznetsk Basin coal and ash is considered, in relation to other regions.     

More efficient operation of the dust-free coke-discharge modules at OAO Zaporozhkoks coke batteries 5 and 6

Two types of dust-free coke-discharge modules are generally employed. The modules employed at OAO Zaporozhkoks are described and analyzed. Methods are proposed for determining their operational efficiency and testing their performance in plant conditions. Recommendations are made for improving the operational efficiency of dust-free coke-discharge modules mounted on door-opening machines.     

Short-range and long-range aggregation of particles in the γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> sol: II. Photometric and ultramicroscopic investigation of the aggregate stability of the positively charged γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> sol

The aggregate stability of the positively charged γ-Al₂O₃ (alundum) sol has been investigated using photometry and flow ultramicroscopy over a wide range of KCl concentrations. The data on the sol stability have been compared with the results of the calculations in the framework of the extended Derjaguin-Landau-Verwey-Overbeek theory. The parameters of the long-range structural forces for γ-Al₂O₃ particles have been evaluated. The role of the far potential minimum in the sol stability has been discussed.