Modified triglycine sulphate (TGS) single crystals for pyroelectric infrared detector applications

Effect of caesium and cerium,l-alanine and caesium +l-alanine impurities are investigated on ferroelectric and pyroelectric properties of TGS crystals. Dielectric constant and loss, pyroelectric coefficient, spontaneous polarization and coercive field measurements of these modified crystals, as a function of temperature are reported. Caesium and cerium did not affect the electrical properties of TGS crystals significantly, whereasl-alanine- and, especially, Cs +l-alanine-doped TGS crystals exhibited promising improvements in pyroelectric properties, up to 48 °C, as compared to pure TGS crystals.     

Characterization of nitric oxide synthase activity in rabbit uterus and vagina: downregulation by estrogen

Nitric oxide synthase (NOS) was determined in the soluble (cytosolic) and particulate fractions of rabbit uterus, vagina and cerebellum and the influence of estrogen treatment on NOS activity was studied. NOS in both the cytosolic and particulate fractions was highly calcium dependent. The activity in cytosolic fraction was nearly 4-fold higher than the particulate fractions from all three organs. The concentration of NOS was highest in cerebellum followed by vagina and uterus. Vaginal NOS activity was 3-4-fold higher than the uterine NOS. After a continuous treatment of rabbits for one week with estrogen, cytosolic NOS was reduced by nearly 7 and 4-fold in the uterus and vagina, respectively, whereas there was no significant change in the particulate NOS. Estrogen treatment caused no change in cytosolic or particulate NOS from the cerebellum. Downregulation of cytosolic NOS by estrogen in the estrogen target tissues like uterus and vagina and absence of effect in the cerebellum strongly suggests a physiological significance.     

Strengthening of a 12CrMoV turbine blade steel by retempering

Commercially available martensitic 12CrMo, 12CrMoV, and HCrMoVNb steels in the tempered condi-tion are often used to fabricate turbine blades. Tempering, done at the processing stage itself, is usually carried out at a temperature approximately 100 to 150 ° above the service temperature. At the service temperature, the steel undèrgoes a second tempering. The effect of this second tempering at a lower tem-perature on the strength of 12CrMoV steel is delineated and discussed in this paper.     

An adaptive mesh refinement technique for the analysis of shear bands in plane strain compression of a thermoviscoplastic solid

We have developed an adaptive mesh refinement technique that generates elements such that the integral of the second invariant of the deviatoric strain-rate tensor over an element is nearly the same for all elements in the mesh. It is shown that the finite element meshes so generated are effective in resolving shear bands, which are narrow regions of intense plastic deformation that form in high strain-rate deformation of thermally softening viscoplastic materials. Here we assume that the body is deformed in plane strain compression at a nominal strain-rate of 5000 sec^-1, and model a material defect by introducing a temperature perturbation at the center of the block.     

A parallel computational approach for similarity search using Bloom filters

Finding similar items in a large and unstructured dataset is a challenging task in many applications of data science, such as searching, indexing, and retrieval. With the increasing data volume and demand for real time responses, similarity search has gained much consideration. In this paper, a parallel computational approach for similarity search using Bloom filters (PCASSB) has been proposed, which uses Bloom filter for the representation of features of document and comparison with user's query. Query features are stored in integer query array (^IQ_A), an array of integer. The PCASSB, an approximate similarity search technique, has been implemented on graphics processing unit with compute unified device architecture as the programming platform. To compute the similarity score between query and reference dataset, Dice coefficient has been used as a baseline method. The accuracy of the results generated by PCASSB is compared with the baseline method and other state‐of‐the‐art methods. The experimental results show that the proposed technique is quite effective in processing large number of text documents as it takes less computational time.     

Roller bearing lubrication with shear thinning lubricants

Lubricants are continually being subjected to increasing mechanical shearing forces. Consequently the interest in materials of variable viscosity has increased. The problem of a roller bearing lubricated by a Casson fluid, which is a shear thinning lubricant, has been investigated; the non-sliding steady state and the squeezed film situation have been studied. At high speeds the load capacity of the Casson fluid is equal to that for a Newtonian fluid of the same viscosity. At low speeds the difference is significant; the Casson fluid film has a load capacity even if the velocities of both cylinders in contact are zero.     

N-type silk fibroin/TiO2 nanocomposite transparent films: electrical and optical properties

This paper highlights the effect of different concentrations of titanium dioxide (TiO₂) nanoparticles on the electrical and optical properties of silk fibroin (SF). TiO₂ based SF nanocomposite films were prepared using the solvent casting method. Uniform dispersion and agglomeration of nanoparticles, in nanocomposite films, were observed by field emission SEM. The conductivity of pure SF and nanocomposite films was determined by a four-point probe and the TiO₂ nanoparticles were found to bring high conductivity to the nanocomposite films. Dielectric strength improved with the addition of nanoparticles to the SF matrix. Dielectric constant and capacitance of the pure SF and nanocomposite films were measured using an LCR meter, which showed a 10-fold enhancement on the addition of nanoparticles in SF. A very unusual property, i.e. negative resistance, was observed during LCR meter analysis for the nanocomposite films for a particular range of frequency (200–550 kHz), voltage (1 V) and current (0.5–1.5 μA). TiO₂ nanoparticles changed the semiconducting behavior of the SF films from p-type to n-type as measured by the Hall effect experiment. The optical properties of pure SF and nanocomposite films were measured using a UV–visible spectrophotometer. The increased concentration of nanoparticles in the SF has effectively enhanced the absorbing coefficient, refractive index and percentage transmittance and reduced the bandgap energy. These SF/TiO₂ nanocomposite films have shown the potential to be used as dielectric and high refractive index material for optoelectronics applications. © 2021 Society of Industrial Chemistry.     

Cetyl Trimethyl Ammonium Bromide Modified Montmorillonite-Doped Tasar Silk Fibroin/Polyvinyl Alcohol Blend 3D Nanowebs for Tissue Engineering Applications

Cetyl trimethyl ammonium bromide (CTAB) modified montmorillonite (MMT) clay (CTAB-MT) doped, tasar silk fibroin-polyvinyl alcohol blend-based 3D nanowebs are generated through electrospinning technique. The morphological analysis reveals the formation of interlinked 3D nanoweb-like architecture and high surface roughness through scanning electron microscopy (SEM) and atomic force microscopy, respectively. The existence of CTAB-MT in nanowebs is confirmed by Fourier transform infrared and complete exfoliation of clay in the polymer blend matrix along with the altered crystallinity of samples is indicated in X-ray diffraction. The incorporation of CTAB-MT clay has shown the enhancement of thermal and mechanical properties of nanoweb samples while the water uptake capacity is reduced and enzymatic biodegradability is found to slow down. The samples present excellent biocompatibility with no cytotoxicity in the Alamar blue assay and high attachment as well as spreading of L929 fibroblast cells covering the entire surface as observed in SEM. The CTAB-MT clay has imparted the samples with good antimicrobial activity against E. coli and S. aureus bacterial strains. The aforementioned properties of these CTAB-MT clay doped 3D nanowebs direct toward their suitability as a potential candidate for tissue engineering applications in the biomedical field.