Photoelastic Measurement of High Stress Profiles in Ion-Exchanged Glass

Photoelastic fringes were directly measured to fully characterize high magnitude, steep compressive stress gradients in an ion-exchanged glass, trade named Ion-Armor™. Initially, using a thick (9.9 mm) rectangular bar and circular polariscope arrangement the overall residual stress profile in a bulk specimen was determined. However, due to the relatively large thickness of the specimen, the high density of fringes (steep stress gradient) close to the edge of the specimen became too diffused to allow an accurate count of fringe order. A thinner (0.71 mm) specimen was then used along with a polarizing light microscope to enhance the fringe contrast. This arrangement yielded approximately four isochromatic fringes, representing a maximum surface compressive stress of 984 MPa, which rapidly decreased to ~300 MPa within 25 μm depth from the strengthened surface. Also, the case-depth of the ion-exchange process was found to be 0.8 mm. Thus, the technique was able to directly capture the extremely high residual compressive stresses generated in an ion-exchanged glass. The current technique utilized for residual stress measurement is more objective and straightforward to implement than what is specified in ASTM standard C-1422, particularly for those specimens having steep stress gradients just below the strengthened surface.     

Lattice Boltzmann Method Applied to Radiative Transport Analysis in a Planar Participating Medium

This article deals with the extension of the usage of the lattice Boltzmann method (LBM) to the analysis of radiative heat transfer with and without conduction in a one-dimensional (1-D) planar participating medium. A novel lattice needed for the calculation of the volumetric radiation spanned over the 4π spherical space has been introduced. The LBM formulation is tested for three benchmark problems, namely, radiative equilibrium, nonradiative equilibrium, and a combined mode conduction–radiation problem in a planar geometry. In the combined mode problem, with radiative information known from the proposed lattice structure, the energy equation is also formulated and solved using the LBM. The D1Q2 lattice is used in the energy equation. For validation, in problems 1 and 2, the LBM results are compared with the finite-volume method (FVM), while in problem 3, the LBM-LBM results are compared with the LBM-FVM in which FVM is used for the computation of radiative information. Comparisons are made for the effects of the governing parameters such as the extinction coefficient, the scattering albedo, and so on, on heat flux and emissive power (temperature) distributions. LBM results are found to be in excellent agreement with the benchmark results.     

License plate localization based on a probabilistic model

Extraction of the license plate region is the challenging first step in the license plate recognition system. We propose a novel feature fusion concept for plate extraction. The image-feature extraction process is modeled as a feature-detection problem in noise. The geometric features are probabilistically modeled and detected under various detection thresholds. These detection results are then fused within the Bayesian framework to obtain the features for further processing. Along with a probabilistic model, a pixels voting algorithm is also tested through threshold variation.     

Transient response of a planar participating medium subjected to a train of short-pulse radiation

Transient response of a planar participating medium subjected to a short-pulse diffuse or collimated radiation is investigated. The pulse-width of the radiation is of the order of a nano-second. Short-pulse radiation can have a step or a Gaussian temporal variation. The homogenous participating medium with diffuse-gray boundaries is absorbing and scattering. The north boundary of the participating medium can be under the influence of a pulse train consisting of 1–4 pulses. The analysis is done using the finite volume method. Effects of the extinction coefficient and the scattering albedo on transmittance and reflectance signals are studied for a train of pulses. Unlike the previous studies with a single-pulse, a train of pulses provides more useful information about the medium.     

Binary liquid–liquid equilibria of aniline–paraffin and furfural–paraffin systems

Binary liquid-liquid-equilibria data for several aniline-paraffin and furfural-paraffin systems have been taken. These data along with data for other aniline-hydrocarbon and furfural-hydrocarbon systems from literature have been correlated using UNIFAC model. The UNIFAC group interaction parameters have been found to have a linear temperature dependence. The CH₂ groups in cyclo and non cyclo paraffins require different interaction parameters. It was also found that a scaling of the combinatorial term is necessary for higher molecular weight hydrocarbons.     

Bi-Allelic Mutations in Zebrafish pank2 Gene Lead to Testicular Atrophy and Perturbed Behavior without Signs of Neurodegeneration

Coenzyme A (CoA) is an essential cofactor in all living organisms, being involved in a large number of chemical reactions. Sequence variations in pantothenate kinase 2 (PANK2), the first enzyme of CoA biosynthesis, are found in patients affected by Pantothenate Kinase Associated Neurodegeneration (PKAN), one of the most common forms of neurodegeneration, with brain iron accumulation. Knowledge about the biochemical and molecular features of this disorder has increased a lot in recent years. Nonetheless, the main culprit of the pathology is not well defined, and no treatment option is available yet. In order to contribute to the understanding of this disease and facilitate the search for therapies, we explored the potential of the zebrafish animal model and generated lines carrying biallelic mutations in the pank2 gene. The phenotypic characterization of pank2-mutant embryos revealed anomalies in the development of venous vascular structures and germ cells. Adult fish showed testicular atrophy and altered behavioral response in an anxiety test but no evident signs of neurodegeneration. The study suggests that selected cell and tissue types show a higher vulnerability to pank2 deficiency in zebrafish. Deciphering the biological basis of this phenomenon could provide relevant clues for better understanding and treating PKAN.     

Fiber Quality Evaluation of Pakistan’s Locally Developed Cotton Varieties for Yarn Manufacturing

This paper discusses relation between fiber quality parameters and yarn quality, presenting results of the quality assessment of Pakistan’s five popular cotton varieties. Abadgar-901 was found to have highest effective length followed by Tarzen-1 when compared to other fibers studied and the Sattari showed the least effective length. Whereas, Tarzen-1 showed highest tenacity, Sindh-1 was second to that, yet Nayab-78 showed the least strength of the studied cotton fibers. Further, it was also found that except Nayab-78, all the other cotton varieties were found to have fineness value of premium cotton standards, however, Nayab proved to be a coarse fiber, Sindh-1 was finest fiber of them all. Moreover, Sattari was found to be the whitest in color when measured for CIE and Berger whiteness index, Nayab-78 followed it just after and the Abadgar proved to be the least white compared to the studied cotton varieties.