Temperature Dependent Magnetic, Dielectric Studies of Sm-Substituted Bulk BiFeO3

Bismuth ferrite- (BiFeO₃) ceramic is the most studied and attractive multiferroic material with low magnetization, moderate leakage current, and low polarization. Samarium substituted bulk BiFeO₃ prepared at low synthesis temperature ??600?°C by the sol?Cgel process. Room temperature X-ray diffraction (XRD) patterns confirmed the formation of perovskite structure Bi_0.9Sm_0.10FeO₃ (BSFO) phases. Present compositions possess high dielectric constant (????199) and low dielectric loss (tan????0.009) at room temperature for 100?Hz frequency. Room temperature dielectric permittivity and dielectric loss decreased with increasing frequency from 100?Hz to 10 MHz. As the temperature increased, an enormous increase in both dielectric permittivity and dielectric loss is observed at all frequency regions. Temperature dependent M?CH hysteresis loops were saturated. Spin glass-like ferromagnetic behavior is retained in M?CH hysteresis loops measured from the low temperature region and normal ferromagnetic behavior is observed in the high temperature region, both at room temperature and above ??350?K, 400?K, respectively. The origin of the ferromagnetic property in BSFO may be due to the presence of rare earth metal ions at the lattice sites of?BFO.     

Microstructure and Mechanical Behavior of a Mini-Thixoformed Tool Steel

We report on mini-thixoforming of a hard and wear-resistant crucible particle metallurgy tool steel. Significant microstructural modifications associated with the special semisolid forming process are characterized in detail by scanning electron microscopy and X-ray diffraction. The mechanical performance of the material is assessed both pre-thixoforming and post-thixoforming by nanoindentation of the constituent phases. The novel microstructural changes that result from mini-thixoforming, which are discussed in this article for the first time, are beneficial in further improving the hardness of the steel.     

Effects of Fats and Oils on Rheological, Fatty Acid Profile and Quality Characteristics of South Indian Parotta

Keeping in view the present day demand for foods with healthy fats, the effect of different fats namely hydrogenated fat (HF) and bakery fat (BF); oils—sunflower oil (SFO), soyabean oil (SBO), olive oil (OLO), palm oil (POO) and coconut oil (CNO) separately at the level of 7.5 % on the rheological, fatty acid profile and quality characteristics of parotta was studied. Addition of fats and oils decreased Farinograph water absorption, Amylograph peak viscosity, Alveograph resistance of dough to deformation and increased average abscissa at rupture. In the micrographs of parotta dough with fats, the protein matrix appeared thick and intact, whereas in the case of parotta dough with oils the protein matrix appeared slightly less intact. The spread ratio and overall quality of parotta with oils were higher than fats. The highest overall quality score was observed for parotta with OLO, followed in decreasing order by SFO, SBO, CNO, POO, HF and BF. Determination of fatty acid profile showed that the parottas with fats contained a high amount of trans fatty acids (TFA), while parottas with oils had no TFA. During storage up to 48 h, the parottas with oils remained softer than the parottas with fats.     

A palmprint based biometric authentication system using dual tree complex wavelet transform

Palmprint identification has emerged as one of the most popular and promising biometric modalities for personal identity verification due to its ease of acquisition, non-invasive procedure, high user acceptance and reliability. This paper proposes the development of a new method for palmprint based biometric authentication which utilizes the textural information available on the palmprint by employing the Dual Tree Complex Wavelet Transform (DTCWT). The method proposes to construct a region of interest (ROI) for the scanned color images of the palm, and then determine a histogram of the two dimensional image. This enables to utilize a feature extraction module, implemented using the one-dimensional (1D) Dual Tree Complex Wavelet Transform (DTCWT) on the histogram signal. The DTCWT is an improvement over the discrete wavelet transform (DWT) as it provides nearly shift invariant performance, reduced aliasing and directional wavelets in higher dimensions. Backpropagation neural-network (BPNN) based binary classifiers are developed for authentication utilizing the features extracted. The system is developed on the basis of several scanned color images of palms of individuals in real-life, in our laboratory. The experimental results obtained from the data have demonstrated the utility of the proposed system, by exhibiting an overall mean accuracy as high as 98.35%.     

Freeze drying technique for microencapsulation of Garcinia fruit extract and its effect on bread quality

Microencapsulation is an enduring technology for protection and controlled release of food ingredients. The Garcinia cowa fruit rinds are rich source of (−)-hydroxycitric acid (HCA), which is reported to have various health benefits. But, HCA is hygroscopic in nature and thermally sensitive. Hence, G. cowa fruit extract was microencapsulated using three different wall materials such as whey protein isolate (WPI), maltodextrin (MD) and combination of whey protein isolate and maltodextrin (WPI + MD in 1:1 ratio) by freeze drying at 30% concentration. The microencapsulated powders were evaluated for their impact on bread quality and free HCA concentration. The microcapsules exhibited wider particle size range of 15–100 μm and HPLC analysis showed that all the three encapsulates yielded higher free (above 85%) and net (above 90%) HCA recovery. Moreover, bread with WPI encapsulates exhibited higher volume, softer crumb texture, desirable colour and sensory attributes and had higher free HCA concentration. This indicated that WPI has excellent encapsulation efficiency than other two wall materials during bread baking.     

Influence of Sediment Layers on Dynamic Behavior of Aged Concrete Dams

The assessment of response of an aged concrete dam is important for the prediction of its behavior during earthquakes, so that remedial measures can be taken at the right time to withstand future earthquakes. The assessment is necessary, since the analyses procedures may become obsolete and the state of the art may change as the time of construction and the structural material may deteriorate due to harsh environmental conditions. At the same time, the sediment will be accumulated at the reservoir bottom on the upstream side of the dam. The process of siltation depends on the reservoir topography and climatic variability, i.e., increased flood frequency and river inflow. The decision of retrofitting or strengthening the aged dam necessitates accurate analysis of the same in the presence of accumulated sediment. In this paper, an approach to include the time-dependent degradation of concrete owing to environmental factors and mechanical loading in terms of isotropic degradation index is presented. The absorption of pressure waves at the bottom of the reservoir due to the presence of sediments has been incorporated in the hydrodynamic pressure equation. The response of an aged concrete dam in the presence of sediment layers under seismic excitation is studied. The outcomes show the efficiency of the proposed algorithm.     

Effect of storage on the rheological and parotta-making characteristics of frozen parotta dough

The effect of storage of frozen parotta dough (FPD) and ready-to-bake frozen parotta dough (R-FPD) at -20 °C for 3 months on the rheological and baking characteristics, respectively, were studied. The optimum thawing conditions for FPD and R-FPD were found to be 1 min in the microwave oven or 16 h in the refrigerator. The rheological characteristics of FPD showed a decrease in farinograph peak consistency from 240 to 200 BU and an increase in extensograph extensibility from 155 mm to 170 mm due to storage. The major protein fractions of FPD as indicated by the electrophoretic patterns remained unchanged up to a period of 3 months. However, when compared to FPD the protein bands in the high-molecular-weight region of glutenin were less intense for baked parotta from R-FPD. The overall rating of parotta was good even after 3 months of storage as indicated by the sensory evaluation of parottas from R-FPD samples.     

Enhanced Piezoelectric Properties of Praseodymium‐Modified Lead‐Free (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 Ceramics

The role of Pr₆O₁₁ addition on the structure, microstructure, electrical, and electromechanical properties of lead‐free (Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)O₃ piezoelectric ceramics has been systemically investigated. Addition of praseodymium (Pr) results in improved ferroelectric and piezoelectric properties. XRD analysis revealed the co‐existence of rhombohedral (R) and tetragonal (T) phases at room temperature. High remanent polarization values (2P_r ~17 μC/cm²) and loop squareness of nearly 0.87 were obtained for the BCZT‐0.04 wt%Pr ceramic, along with high piezoelectric coefficient (d₃₃ = 435 pC/N) and transduction coefficient [(d₃₃·g₃₃) = 11589 × 10^?15 m²/N]. Results are correlated with the crystal structure and microstructure that significantly influence the ferroelectric and piezoelectric properties near the R–T phase transition point. This material seems to be especially suitable for energy harvesting applications, exhibiting outstanding figure of merit.