Mary Alice White (1920-2000).

Memorializes Mary Alice White for her many contributions to school psychology. White was foremost an experimental and behaviorally oriented educational psychologist, whose interests cut across educational, clinical, and school psychology and technology applications to schooling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic experimental simulation of hydrogen oriented underground gasification of lignite

The main goal of the study presented in the paper was to experimentally demonstrate the feasibility of lignite gasification to hydrogen-rich gas under the underground conditions simulated in the ex situ reactor. The in situ gasification conditions were simulated both in respect to the coal seam and the surrounding stratum. In the 54-h experiment the process of lignite gasification with oxygen and steam as gasifying medium was tested. The experiment was initially divided into three stages: the ignition stage, the oxygen stage and the steam stage.The gas produced in the steam gasification stage was characterized by the calorific value of 7.8 MJ/m³ and average hydrogen content of 46.3 vol.%. Unfortunately a rapid decrease in the temperature levels and in the amount of produced gas proved that the tested lignite of 53 vol.% moisture content was not suitable for steam gasification. A great amount of thermal energy was consumed for water evaporation which led to a considerable heat loss. An addition of stoichiometric amount of water in the system by adding steam caused the seam to extinguish. Thus only oxygen could be used as the gasifying medium in the gasification of the tested lignite. The average calorific value of gas produced in the stable operation during oxygen gasification stage equaled 5.2 MJ/m³ with the average gas production rate of 16.0 m³/h and the average hydrogen content in the produced gas of 26.4 vol.%.     

Electrospun ultrathin nylon fibers for protective applications

Electrospun nylon 6 fiber mats were deposited on woven 50/50 nylon/cotton fabric with the motive of making them into protective material against submicron‐level aerosol chemical and biological threats. Polymer solution concentration, electrospinning voltage, and deposition areal densities were varied to establish the relationships of processing‐structure‐filtration efficiency of electrospun fiber mats. A high barrier efficiency of greater than 99.5% was achieved on electrospun fiber mats without sacrificing air permeability and pressure drop. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A Solvent‐Free Dispersion Method for the Preparation of PET/MWCNT Composites

A simple, easily accessible solvent‐free method for the dispersion of MWCNTs into PET is proposed, based on the preparation of a microparticulate polymer/nanotube masterbatch via cryogenic impact‐milling and its subsequent melt blending with the bulk polymer. Thermal and mechanical properties of nanocomposites prepared using this method were evaluated as a function of nanotube concentration. Thermal stability was improved, and superior crystallization behavior of PET in the nanocomposites was observed. Significant improvements of around 25% in tensile strength and tensile modulus of the nanocomposites was achieved using this strategy, with only 0.25 wt.‐% MWCNT, compared to previous literature data where 1 wt.‐% MWCNT was employed.

     

Properties of welded joints made of Weldox 1100 steel

This study evaluated both the joint strength of copper wire on a copper substrate with tin plating and the joint reliability of copper wire bonding after heat treatment. The suitable tin thickness and bonding conditions, which are stage temperature, wire bonding power and bonding time, were chosen by the peel test after copper wire bonding. Tin thickness of 10 m showed a high bonding rate under the conditions of stage temperature 373 K, bonding power 500–700 mW and bonding time 30 50 ms. Before heat treatment, the peel strength of the copper wire on the copper substrate with tin plating conditions was weaker than that of gold wire on a gold substrate. After heat treatment for more than 70 h at 298 K, the peel strength of the copper wire became higher than that of the gold wire and twice as high as the initial bonding strength. The tin layer remained between the copper wire and copper substrate before heat treatment. When the samples were held at 298 K, tin reacted with copper and turned into a Cu–Sn intermetallic compound. Upon completion of this reaction at 298 K for over 70 h, the soft tin layer between the copper wire and copper substrate disappeared. Therefore, the peel strength of copper wire after heat treatment increased. These results were observed by scanning electron microscope images of the interface between the copper wire and copper substrate before and after heat treatment.     

A facile approach to fabricate porous nylon 6 nanofibers using silica nanotemplate

Porous Nylon 6 nanofibers were prepared using silica nanoparticles as the template. Firstly, Nylon 6/silica composite nanofibers were prepared as precursors by electrospinning Nylon 6 solutions containing different contents of silica nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the surface morphology and the inner structure of composite nanofibers; where it was found that silica nanoparticles were distributed both inside and on the surface of nanofibers. Analytical techniques [Fourier transform infrared (FTIR), differential scanning calorimetry, thermal gravimetric analysis (TGA), and wide‐angle X‐ray diffraction) were used to study the structure and properties of these composite nanofibers. The glass transition, melting, and crystallization processes of the fibers were affected by the addition of silica nanoparticles. Secondly, porous Nylon 6 nanofibers were obtained by removing silica nanoparticles via hydrofluoric acid treatment. The removal of silica nanoparticles was confirmed using FTIR and TGA tests. SEM and TEM observations revealed the formation of the porous structure in these nanofibers. After the formation of the porous structure, Brunauer–Emmett–Teller specific surface areas of nanofibers were increased as compared to solid Nylon 6 and composite nanofibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Practical Algorithms for Online Thermal Stress Calculations and Heating Process Control

This article presents two algorithms for online mode thermal stress determination in machinery components based on Green's Function Technique approach and on the artificial neural network, respectively. A modification of the GFT algorithm is proposed involving the use of the component metal temperature rather than the temperature of the flowing fluid. The algorithms developed were used to calculate stresses in rotors and casings of new generation turbines. A possibility was also shown of using the algorithms to solve the inverse problem, i.e., to control the rate of temperature changes while keeping stresses within an allowable range.     

The Effect of Liquid Crystalline Structures on Antiseizure Properties of Aqueous Solutions of Ethoxylated Alcohols

Aqueous solutions of ethoxylated alcohols which form lyotropic liquid crystals at high concentrations (40–80%) were selected as model lubricating substances. Microscopic studies under polarized light and viscosity measurements were carried out in order to confirm the presence of liquid crystalline structures in the case of alcohol solutions with ethoxylation degrees of 3, 5, 7 and 10. Microscopic images and viscosity coefficient values characteristic of various mesophases were obtained. As expected, the viscosity of LLCs decreases considerably with an increase in shearing rate which is characteristic of liquid crystals being non-Newtonian liquids. Antiseizure properties were determined by means of a four-ball machine (T-02 Tester) and characterized by scuffing load (P_t), seizure load (P_oz) and limiting pressure of seizure (p_oz). Alcohol ethoxylates forming mesophases in aqueous solutions have the strongest effect on the P_t values which are several times higher than those measured in the presence of water. Ethoxylates with higher degrees of ethoxylation exhibit higher values of scuffing load. Those changes have been interpreted as a result of higher cloud points at which those compounds lose their amphiphilic properties. In general, the presence of mesophases in the bulk phase and particularly in the surface phase may lead to the formation of a lubricant film which separates the frictionally cooperating elements of a friction pair. The antiseizure efficiency of alcohol solutions is highest up to the load value which does not exceed the scuffing load value.     

Testing butt joints in pipes made of VM12-SHC martensitic steel

VM12-SHC steel is the newest grade of 12% Cr steel developed by the V&M company. At the present moment, there are works being conducted in order to make use of this steel in steam superheaters. It is also planned to implement VM12-SHC steel to the fabrication of water-walls for prototype boilers operated at very high temperature and pressure parameters. In this article, test materials and welding consumbables are characterized and the process of preparation of pipes to be welded is discussed. The results of metallographic examination and mechanical testing of the test joints are presented.