Formation of glass synthesized by sol-gel technology

The process of glass synthesis by the sol-gel method is studied using analysis of EPR spectra. The gelation process and formation of xerogels are considered depending on the temperature-time parameters and the type of initial components. It is established that the glass phase starts to be formed at 800°C. __________ Translated from Steklo i Keramika, No. 8, pp. 9–13, August, 2006.     

Characterization and comparison of PECVD silicon nitride and silicon oxynitride dielectric for MIM capacitors

In this letter, we report on the electrical characteristic and the comparison of the metal-insulator-metal (MIM) capacitors with PECVD silicon nitride (SiN) and silicon oxynitride (SiON). Both capacitors are found to exhibit low leakage and high breakdown field strength, as well as absence of dispersive behavior, good linearity, and comparable quality factor behaviors.     

A New Variable Diffusion Drying Model for the Second Falling Rate Period of Paddy Dried in a Rapid Bin Dryer

The objectives of this article is to propose a new drying model for the second falling rate period known as the variable diffusion controlled period that follows after the first falling rate period and to propose a new method to determine the second critical moisture content that separates these two periods. Experimental work on paddy drying at minimum fluidization velocity was carried out in a rapid bin dryer. The effects of operating temperatures (60-120°C) and bed depths (2-6 cm) on the paddy drying characteristics were investigated. It was found that the normalized drying rate of paddy was proportional to the normalized moisture content in the first falling rate period but in the second falling rate period, the normalized drying rate of the material varies exponentially with the normalized moisture content. The different relationship between the normalized drying rate and the normalized moisture content in the first and second falling rate periods indicate that two different mechanism of moisture transport are at work. The new exponential model of the second falling rate period and the linear model of the first falling rate period were found to fit the experimental data very well. Derivation from variable diffusion equation shows that the linear model is the result of constant diffusion coefficient whereas the new exponential model is the result of linear diffusion coefficient. This also implies that the first falling rate period is a constant diffusion controlled period and the second falling rate period is a variable diffusion controlled period. In addition, drying kinetics data of a drying process that fits the exponential model over a very slow drying period will show that the drying process is under the effect of a linear diffusion coefficient. It was also found that the proposed new method to determine the second critical moisture content that distinguishes between the first and second falling rate periods by using a sudden change in the value of the drying rate gradient to a much lower value at that point is more rigorous and yet simpler than the method of determining the specific location of the receding drying boundary since it is based on the behavior of the actual drying kinetic data.     

Low RF noise and power loss for ion-implanted Si having an improved implantation process

Very-low-transmission line noise of <0.25 dB at 18 GHz and low power loss /spl les/0.6 dB at 110 GHz have been measured on transmission lines fabricated on proton-implanted Si. In contrast, a standard Si substrate gave much higher noise of 2.5 dB and worse power loss of 5 dB. The good RF integrity of proton-implanted Si results from the high isolation impedance to ground, as analyzed by an equivalent circuit model. The proton implantation is also done after forming the transmission lines at a reduced implantation energy of /spl sim/4 MeV. This enables easier process integration into current VLSI technology.     

Thermodynamic Analysis of the Wilson Model Using Partial Excess Functions

An approach to thermodynamic analysis of models of liquid solutions is developed. The approach is based on studying local characteristics of the concentration dependences of the partial excess molar functions. The applicability region is established, and constraints on the parameters of the Wilson equation are found.     

Evaluating the stabilisation degree of digested sewage sludge: investigations at four municipal wastewater treatment plants.

Further reduction of volatile suspended solids (VSS) during a post-stabilisation step was applied to evaluate the stabilisation degree of digested sewage sludge. For this purpose digested sludge was collected at four municipal wastewater treatment plants (WWTPs) and further stabilised in lab-scale chemostat reactors either under anaerobic or aerobic conditions. Experimental results showed that even in adequately digested sludge a consistent amount of VSS was degraded during aerobic post-stabilisation. It seems that aerobic conditions play a significant role during degradation of residual VSS. Additionally, specific VSS production (gVSS/peCOD110.d) as well as specific oxygen uptake rate were shown to be suitable parameters to assess the degree of sludge stabilisation at WWTPs. Fourier transform infrared spectroscopy was used to reveal changes in the sludge composition. Spectra of treated and untreated sludge samples indicated that the major component of residual VSS in stabilised sludge for instance consisted of biomass, while cellulose was absent.     

Oxidized (Cyclized) Polyacrylonitrile Fibres — Oxypan. A Review

Fibres made of oxidized polyacrylonitrile of the Oxypan type are an independent group of thermostable fires with a possible temperature of use of up to 300°C and slightly higher for a short time. The principles and methods of fabrication, structure, assortment, and properties of Oxypan oxidized PAN fibres are examined. Oxypan fibres, widely manufactured in different countries, are now the least expensive of all thermostable fibres. It is expedient to organize manufacture of these fibres in Russia, and the necessary equipment is available and in place.