Development and characterisation of C-Mn-Al-Si-Nb TRIP aided steel

Performance of TRIP (transformation induced plasticity) aided steel depends on the amount and stability of retained austenite in the final microstructure. In the current work, a small sized C-Mn-Si-Al-Nb steel was made and suitably heat treated to produce multiphase TRIP microstructure. A combination of relevant transformation models and empirical artificial neural network based model was used to select the heat treatment parameters required to achieve the desired amount of retained austenite. Characterisation of microstructure carried out using a variety of techniques confirmed the predictions of these models. The alloy was found to have an attractive combination of strength and ductility.     

In Vitro Study of Hydroxyapatite Coatings on Fibrin Functionalized/Pristine Graphene Oxide for Bone Grafting

Fibrin functionalized graphene oxide (FGO) and graphene oxide (GO) were used as nucleation sites for the growth of hydroxyapatite (HA). The growth of HA on GO/FGO was done by wet precipitation method, and they were characterized for their physicochemical properties. Cytotoxicity was confirmed by reactive oxygen species assay and cell viability assay; alkaline phosphatase assay, alizarin red test, and protein expression studies showed that FGHA was an excellent composite for osteoblast cell growth and maturation. Alamar blue assay was used to study the enzymatically degraded cytocompatibility of enzymatically degraded components. Results proved that FGHA might be tried as an osteoinductive material, in orthopedic defects.     

Quantum and dielectric confinements of sub-10 nm gold in dichroic phosphate glass nanocomposites

Blue shifts of the surface plasmon resonance band of sub-10 nm gold in dichroic phosphate glass nanocomposites are observed with increase in both size of gold nanoparticles and refractive index of the medium, which are contrary to the common trends. These phenomena have been enlightened with the electrodynamics theories (Mie and Drude models) and happened due to quantum and dielectric confinements. Nanocomposites have been synthesized by in-situ thermochemical reduction technique in reducing phosphate glass matrices. The plasmon bands are characterized by the UV–vis spectrophotometer, and shape and size of the nanogold by the transmission electron microscopy. All the nanocomposites are dichroic in nature.     

From designer clusters to synthetic crystalline nanoassemblies

Clusters have the potential to serve as building blocks of materials, enabling the tailoring of materials with novel electronic or magnetic properties. Historically, there has been a disconnect between magic clusters found in the gas phase and the synthetic assembly of cluster materials. We approach this challenge through a proposed protocol that combines gas-phase investigations to examine feasible units, theoretical investigations of energetic compositional diagrams and geometrical shapes to identify potential motifs, and synthetic chemical approaches to identify and characterize cluster assemblies in the solid state. Through this approach, we established As7(3-) as a potential stable species via gas-phase molecular beam experiments consistent with its known existence in molecular crystals with As to K ratios of 7:3. Our protocol also suggests another variant of this material. We report the synthesis of a cluster compound, As7K1.5(crypt222-K)1.5, composed of a lattice of As7 clusters stabilized by charge donation from cryptated K atoms and bound by sharing K atoms. The bond dimensions of this supercluster assembled material deduced by X-ray analysis are found to be in excellent agreement with the theoretical calculations. The new compound has a significantly larger band gap than the hitherto known solid. Thus, our approach allows the tuning of the electronic properties of solid cluster assemblies.     

A Block-Level Image Tamper Detection Scheme Using Modulus Function Based Fragile Watermarking

Intentional illegitimate modification in any digital image data is one of the general malversations in the existing digital domain. Therefore in this work, the authors have devised a fragile watermarking technique for the localization of illegitimate modifications in the digital image content effectually. The proposed technique detects forged digital image content strongly in the block-level of two successive pixels. This scheme is performed at the block level, where the actual image is partitioned into non-overlapping blocks of size (1?×?2) pixels. Afterward, the block-level authentication code is generated from the MSB of two successive pixels of each block using averaging and modulus operations. The generated authentication code/watermark is encrypted using a logistic-map-based chaotic key series. The encrypted authentication code is embedded into two successive pixels of the corresponding block. Further, any form of forgery in the watermarked image can be detected by comparing its extracted authentication code and regenerated authentication code. The proposed procedure is successfully experienced on a variety of grayscale images, and the experimental results exhibit that watermarked images generated by this scheme are of considerably high quality in terms of PSNR, IF, and SSIM. The proposed method is capable of efficient forgery detection by achieving very high accuracy, NC, and true positive rate while maintaining considerably low false-positive and false-negative rates.

     

Determination of exposure and probable ingestion of fluoride through tea, toothpaste, tobacco and pan masala

Levels of water soluble and acid soluble fluoride in tea, toothpaste, tobacco and pan masala (mouth freshener) were estimated. These items are, generally, ignored while calculating the total dietary intake of fluoride. Tea, toothpaste, tobacco, pan masala (with tobacco and without tobacco) frequently expose human body to 3.88-137.09, 53.5-338.5, 28.0-113.0, 16.5-306.5 and 23.5-185.0 microg of fluoride per gram of these items, respectively. An effort was also made to quantify, on the basis of available studies, the probable human ingestion of fluoride through these substances. Increased leaching of fluoride from some of these substances has been observed in acidic conditions in the present study. The results can be extrapolated to acidic conditions of human stomach.     

Evaluation of a spindle-based force sensor for monitoring and fault diagnosis of machining operations

This paper presents an evaluation of a spindle-based force sensor, the force ring, which is a strong candidate for in-process monitoring and fault diagnosis of machining operations. The evaluation criteria include the effect of integration of the force ring on the dynamics of the spindle, the drift behavior due to temperature change inside the spindle, the cross-talk between the channels, and the existence and compensation of the spindle-internal forces. The application of the force ring to process model-based monitoring and fault diagnosis has been demonstrated by the determination of force calibration coefficients using the force ring and their comparison with results obtained with a platform dynamometer. It has been concluded that the force ring provides dynamometer quality force measurements.     

Association of GSTM1 and GSTT1 polymorphisms with DNA damage in coal-tar workers

DNA damage was evaluated by alkaline comet assay in peripheral blood lymphocytes of 115 coal-tar workers occupationally exposed to polycyclic aromatic hydrocarbons (PAHs) and 105 control subjects. The effect of polymorphisms of glutathione S-transferase (GST) genotypes on the DNA damage was assessed. The mean tail moment (TM) value in the coal-tar workers was significantly higher as compared to the control subjects (12.06 ± 0.55 versus 0.44 ± 0.31; P < 0.05). No significant association (P > 0.05) between the GSTT1 and GSTM1 genotypes and the TM values was found, however highest mean rank TM value was reported in GSTM1 null and GSTT1 null genotypes in both control and exposed subjects. Our results suggest that there is increased DNA damage in coal-tar workers due to PAHs exposure. Polymorphisms in GSTM1 and GSTT1 genes do not show significant effect (P > 0.05) on DNA damage.