Radiation effect on MHD flow past a porous vertical plate in the presence of heat sink

This study investigates heat and mass transfer in MHD convective flow through a vertical plate via porous media in the presence of radiation and a heat source/sink. It is assumed that a uniform magnetic field of strength is imposed perpendicular to the plate and directed into the fluid area. The governing nondimensional equations are solved using the perturbation technique. We further derived the skin friction, Nusselt number, and Sherwood number. The computation of results is performed with the aid of mathematical software and results are presented in graphical and tabular forms for distinct flow impacting parameters. It is observed that fluid motion is retarded due to the application of the magnetic field. Furthermore, the fluid temperature comprehensively falls under the Prandtl number as well as the thermal radiation effect. It is important to note that the heat sink causes fluid velocity and fluid temperature to fall drastically.     

Time‐Lapse Photometric Stereo and Applications

This paper presents a technique to recover geometry from time‐lapse sequences of outdoor scenes. We build upon photometric stereo techniques to recover approximate shadowing, shading and normal components allowing us to alter the material and normals of the scene. Previous work in analyzing such images has faced two fundamental difficulties: 1. the illumination in outdoor images consists of time‐varying sunlight and skylight, and 2. the motion of the sun is restricted to a near‐planar arc through the sky, making surface normal recovery unstable. We develop methods to estimate the reflection component due to skylight illumination. We also show that sunlight directions are usually non‐planar, thus making surface normal recovery possible. This allows us to estimate approximate surface normals for outdoor scenes using a single day of data. We demonstrate the use of these surface normals for a number of image editing applications including reflectance, lighting, and normal editing.     

Use of extrusion aids for successful production of Kollidon® CL-SF pellets by extrusion–spheronization

Objective: Fine particle ethylcellulose (FPEC) or poly(ethylene oxide) (PEO) addition to a Kollidon CL-SF was investigated to address low yield and poor sphericity in extruded-spheronized pellets.

Significance: The success of crospovidone as a diluent in extrusion–spheronization was dependent on a small particle size of the polymer. FPEC aided production of rugged and spherical pellets using a large particle size grade, Polyplasdone^® XL. PEO acted as an extrusion–spheronization aid when ethylcellulose was the diluent. These extrusion–spheronization aids could serve in this role when Kollidon^® CL-SF (K CL-SF) is the diluent.

Methods: The influence of formulation and process variables on pellet properties was investigated using design of experiments. A planetary mixer was used to prepare powder blends and the wetted mass after addition of water. An EXD 60 extruder produced extrudate that was spheronized in a Q230 marumerizer. Wet pellets were dried in a forced-air oven.

Results: FPEC improved rounding up but reduced pellet yield. Poly(ethylene oxide) imparted desired characteristics to the wetted mass, the extrudate, and the spheronized pellets. Pellet average diameter, yield, sphericity, aspect ratio, friability, and dissolution profile were assessed. Equations for pellet characteristics facilitated discussion of the influences of factors and their interactions. Optimization was performed on pellets that included PEO.

Conclusions: PEO proved to be an exceptional extrusion–spheronization aid in the preparation of pellets using K CL-SF. It facilitated wetted mass extrusion with minimal mass loss to the extruder, and markedly improved the sphericity of the pellets produced by marumerization. Immediate release pellets were obtained.     

Real-time automatic message accounting data transport

In today’s operation, all usage records for billing, regardless of their source, and service type are put into a file/stream and delivered to the downstream revenue accounting office for processing. The revenue accounting office operates in a batch mode, then scans through the records and separates those which are required for special processing by other applications, like fraud management and customer access to network usage data. However, there is a significant delay between the time the usage records are generated to the time they are available to the other systems. This paper proposes solutions to support real-time transfer of automatic message accounting (AMA) records and files. First, the existing automatic message accounting teleprocessing system (AMATPS) architecture is analyzed to study its limitations. Next, transport mechanisms are identified and analyzed. Finally, an alternative to the existing AMATPS architecture is discussed.     

Ultrasonic Characterization of Zirconia-Toughened Alumina Ceramics

Ultrasonic pulse-echo technique was used for the characterization of sintered zirconia-toughened alumina (ZTA) ceramics. The variation of the ultrasonic velocity and elastic constants with the volume fraction of zirconia in the alumina matrix was studied. The ultrasonic velocity variation in these materials also was modeled using a mean-value approach. The zirconia grains in ZTA were modeled by oblate spheroids, whose aspect ratio was estimated from the two-dimensional microstructure of the material using stereological relations. The aspect ratio was then used as a parameter to estimate the ultrasonic velocity variation in the material using self-consistent spheroidal inclusion theory, and the model was validated by comparing the estimated data with the measured velocity values, which showed very good agreement.     

Component structure of individual differences in true and false recognition of faces.

Principal-component analyses of 4 face-recognition studies uncovered 2 independent components. The first component was strongly related to false-alarm errors with new faces as well as to facial “conjunctions” that recombine features of previously studied faces. The second component was strongly related to hits as well as to the conjunction/new difference in false-alarm errors. The pattern of loadings on both components was impressively invariant across the experiments, which differed in age range of participants, stimulus set, list length, facial orientation, and the presence versus absence of familiarized lures along with conjunction and entirely new lures in the recognition test. Taken together, the findings show that neither component was exclusively related to discrimination, criterion, configural processing, featural processing, context recollection, or familiarity. Rather, the data are consistent with a neuropsychological model that distinguishes frontal and occipitotemporal contributions to face recognition memory. Within the framework of the model, findings showed that frontal and occipitotemporal contributions are discernible from the pattern of individual differences in behavioral performance among healthy young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leveraging disposable instrumentation to reduce coverage collection overhead

Testers use coverage data for test suite quality assessment, stopping criteria definition, and effort allocation. However, as the complexity of products and testing processes increases, the cost of coverage data collection may grow significantly, jeopardizing its potential application. To mitigate this problem this paper presents the concept of ‘disposable coverage instrumentation’—coverage instrumentation that is removed after its execution—through two techniques: local disposal, and collective disposal. A Java virtual machine was extended to support these techniques, and their potential is shown through two studies utilizing the Specjvm98 and Specjbb2000 benchmarks. The results indicate that the techniques can reduce coverage collection overhead by an order of magnitude over state‐of‐the‐art techniques. Copyright © 2006 John Wiley & Sons, Ltd.     

Interfacial properties of metallized alumina ceramics

An alumina ceramic material (purity-96%) was metallized by the conventional molybdenum-manganese (Mo-Mn) process in which an alumina substrate was coated with Mo-Mn paste and subsequently heat treated at 1400 °C for 10 min. During the entire process a moist H₂ and N₂ gas mixture (dew point-20 °C) with 3:1 ratio was passed continuously through the furnace. X-ray diffraction analysis of the metallized alumina substrate identified only molybdenum phase at the surface of the metallizing layer. The microstructural observations of the metallized alumina substrate were made by scanning electron microscopy. Energy dispersive X-ray analysis showed the elemental compositions along the cross-sectional region of the metallized alumina substrate. The adhesion of the metallic coatings on the alumina substrates was evaluated qualitatively by a scratch testing technique and quantitatively by an adhesion tester. Nanohardness measurements showed gradual change in the nanohardness values across the metallized alumina substrate.     

Experimental study of aerodynamic resuspension of RDX residue

Residues of hazardous substances, such as chemical compounds with low vapor pressure, radioactive particles, or biological contamination can remain on surfaces for a prolonged period of time. The fate of these particles partially depends on the aerodynamic resuspension rates from the surfaces that are a function of particle and surface properties as well as the environmental conditions. The aerodynamic resuspension can be used for non-contact surface sampling. The removal rates of microscopic explosive trimethylenetrinitramine (RDX) particles from smooth glass surfaces in a controlled flow environment are investigated in this paper. The shear stress in the flow cell is calculated using computational fluid dynamics as a function of velocity. The RDX particle samples are prepared by dry transfer. Particle sizes and morphologies are measured by 3D scanning electron microscopy (SEM) and optical profilometry. The resuspension rates are calculated based on the changes in the total coverage area before and after exposure to aerodynamic forces. These rates are correlated with wall shear stresses, particle size, and morphology. For non-spherical particles, the removal rates are proportional to the particle shape factor defined as a ratio of particle height to the projected equivalent diameter.

Copyright © 2019 American Association for Aerosol Research     

A Novel Method of Predicting Ultrasonic and Elastic Properties of Isotropic Ceramic Materials after Sintering from the Properties of Partially Sintered or Green Compacts

A novel method for predicting the porosity dependence of ultrasonic and elastic properties of isotropic ceramics after sintering based on the properties of green or partially sintered compacts has been proposed. The method is based on the observation that the ratio of ultrasonic shear wave to longitudinal wave velocity is a function of porosity only and varies linearly with the longitudinal wave velocity. It is also shown that the predicted trend of variation of Poisson's ratio with porosity agrees with the predictions of the Mori–Tanaka mean field approach. The method can be used as a quality control tool during the preparation of ceramic materials.