Phase relations in the oxygen rich region of the CrWO ternary system

The phases occurring in the ternary CrWO system at 1370 K have been determined using x-ray diffraction and electron and optical microscopy. It was found that at this temperature no Cr enters WO₃ or the other tungsten oxides and no ternary CS phases appear to form. Instead, the Cr reacts to form one or two ternary rutile phases and equilibrium lies between them and the appropriate binary tungsten oxide. The compositions of these ternary oxides are Cr₂WO₆ and a previously unreported phase CrWO₄. No extended homogeneity ranges have been detected for these oxides. A phase diagram summarises the results which are also considered in the light of the formation of crystallographic shear phases in tungsten oxides.     

Critical magnetic fields of Cu-Pb-Cu proximity-effect sandwiches studied by acoustic surface waves

The temperature dependence of the surface-wave attenuation in Cu-Pb-Cu sandwiches, in the absence of a magnetic field, agrees well with the BCS expression. We compare the temperature dependence of the parallel and perpendicular critical fields with expressions derived from the Ginzburg-Landau theory. We get satisfactory agreement, provided that for the thinner specimens we take the mean free paths in the proximity-effect sandwich to be somewhat smaller than the values found for monitor strips. This implies that some interdiffusion between the Pb and the Cu is taking place.     

Quantitative assessment of wheat quality using near-infrared spectroscopy: A comprehensive review

Wheat is one of the most widely cultivated crops throughout the world. A great need exists for wheat quality assessment for breeding, processing, and products production purposes. Near-infrared spectroscopy (NIRS) is a rapid, low-cost, simple, and nondestructive assessment method. Many advanced studies associated with NIRS for wheat quality assessment have been published recently, either introducing new chemometrics or attempting new assessment parameters to improve model robustness and accuracy. This review provides a comprehensive overview of NIRS methodology including its principle, spectra pretreatments, spectral wavelength selection, outlier disposal, dataset division, regression methods, and model evaluation. More importantly, the applications of NIRS in the determination of analytical parameters, rheological parameters, and end product quality of wheat are summarized. Although NIRS showed great potential in the quantitative determination of analytical parameters, there are still challenges in model robustness and accuracy in determining rheological parameters and end product quality for wheat products. Future model development needs to incorporate larger databases, integrate different spectroscopic techniques, and introduce cutting-edge chemometrics methods. In addition, calibration based on external factors should be considered to improve the predicted results of the model. The NIRS application in micronutrients needs to be extended. Last, the idea of combining standard product sensory attributes and spectra for model development deserves further study.     

The formation of phases in the AlN-rich corner of the Si-Al-O-N system

The reaction of AlN with Al₂O₃, SiO₂ or Si₃N₄ and Al₂O₃ at temperatures of 1820°C and 1950°C and for compositions rich in AlN have been investigated using powder X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. At 1820°C, Al₂O₃ reacted with AlN to form the non-stoichiometric oxynitride spinel phase (≈Al₂₃O₂₇N₅), whereas samples on the AlN-SiO₂ and AlN-‘X-phase’ tie-lines did not react. At 1950°C, AlN-Al₂O₃ mixtures reacted to form the 27R aluminium oxynitride polytypoid, AlN---SiO₂ mixtures reacted to form 21R and 27R sialon polytypoids and AlN-‘X-phase’ mixtures reacted to form the 12H, 21R and 27R sialon polytypoids, all of which possessed a needle-like morphology. Ordered and disordered intergrowths were also observed in the polytypoid crystals but the disordered 2H^δ sialon phase was not found.     

Microwave heating of laminate panels

The use of microwaves to heat laminate panels occurs in a variety of industrial processes, from chemical vapor infiltration (CVI) systems to the curing of adhesives in laminate panels. The electrical conductivity of the materials used in these systems is typically temperature-dependent. Characteristically, the thickness of the laminate panel is on the order of wavelength of the incident microwave, but the thickness of the laminate sheet is much smaller. This allows us to apply asymptotic techniques to find averaged wave and heat equations when the direction of the incident microwave is normal to, or tangent to, the laminates. These equations are analyzed in the small-Biot-number limit and are numerically approximated using finite differences. The results are in excellent agreement for small Biot numbers. More importantly, heating trends are observed for a wide variety of volume fractions for two particular CVI applications. In addition, the effect of the incident polarization on the heating process are also established. In particular, the use of a TE polarized incident microwave is shown to be inefficient in certain CVI applications, but produces a more favorable temperature gradient.     

Testing and Evaluating Alternative Algorithms for Location Referencing System Route Generation

Modeling the transportation network of roads and highways for data and information system implementations presents unique challenges. The foremost challenge is selecting a modeling methodology that is compatible with the needs and culture of the organization using it. The second challenge is implementing the model in a viable enterprise information system via a database. Transportation information systems must efficiently store network topology and geometry, as well as attributes, and they must be compatible with geographic information systems (GIS). This paper deals with the topological aspects of the highway network. In particular, it describes computing methodologies for generating location referencing system routes. The paper describes the link node referencing system used to build the routes and mentions an alternative approach using GIS. Various algorithms are presented and described, test case results are presented, the algorithms are compared, and evaluation criteria are defined.     

The preparation and properties of an antimony sulphide glass

A glass has been prepared in the Sb₂S₃PbS system at compositions very close to 80 mol % Sb₂S₃: 20 mol % PbS. It has been studied by powder x-ray diffraction, optical and high resolution transmission microscopy and infra-red spectroscopy, and its decomposition characterised by differential scanning calorimetry. Hardness values are also reported. This glass displays a wide range of transparency from 4.5 to 16.5 μm and may be of interest for a number of infrared applications. Structural studies indicate that it is formed of SbS and PbS polyhedra similar to those found in the crystalline PbSbS sulphides, and recrystallisation of the glass, observed by electron microscopy shows that the rearrangement of the polyhedra in transforming from the glass state to the crystalline state is feasible. The formation of the glass and its limited composition range are discussed in terms of the strain involved in linking the PbS and SbS polyhedra together and this leads to a number of suggestions as to how the existence region over which the glass forms could be expanded.