Synthesis and characterization of in-situ reinforced Fe-TiC steel FGMs

This paper presents a novel technique to synthesize TiC-reinforced iron base (Fe-TiC) functionally graded materials (FGM) using SHS reaction followed by centrifugal casting. The in-situ reinforced Fe-TiC steel composites were prepared by aluminothermic SHS reactions using metal oxides and elemental powders. Ferritic as well as austenitic matrix Fe-TiC composites were obtained by judicious thermite charge composition. FGM microstructure was characterized in terms of TiC area fraction, particle size, and chemical analysis using optical and analytical electron microscopy. The results reveal a gradient of TiC particles across the thickness in the inner face and a particle-free region in the outer surface. Hardness profiles have shown an increasing trend from outer surface to TiC-rich inner surface. Wear studies indicated better wear performance of TiC-rich inner face as compared to particle-free outer surface of ferritic or austenitic steel matrices.      

A Comparative Study of the Inter-Relationships Between Mixograph Parameters and Bread- Making Qualities of Wheat Flours and Glutens

The mixing characteristics and bread-making qualities of flours, reconstituted flours and glutens from a diverse range of wheat cultivars obtained from Canada, France and the UK, were investigated. Simple correlations were calcu-lated among Mixograph parameters, loaf volume, Glu - 1 quality scores, protein content, SDS-sedimentation volume and baking absorption. The results indicate that the mixing properties of flours from cultivars in the medium–strong range are significantly influenced by their protein contents. On the other hand, the mixing properties of ‘extra strong’ or weak flours are relatively less affected by their protein contents, and it appears that the protein quality primarily controls their behaviour during mixing. Gluten samples, other than weak glutens from cvs Riband and Corin, required a longer time to mix to peak dough resistance (PDR) than their corresponding flour or reconstituted flour samples. However, the differences in mixing time were more pronounced between ‘extra strong’ glutens and their corresponding flours or reconstituted flours. The Mixograph parameter PDR showed highly significant ( P< 0·001) correlations with loaf volume for flour, reconstituted flour and gluten samples. In each case, variation in PDR explained more than 65% of the variation in loaf volume, reaching about 83% for glutens. PDR was also significantly correlated with Glu - 1 quality scores. However, the mixing times for flours, reconstituted flours and glutens demonstrated no simple correlations with loaf volume. On the basis of the results, it appears that the 2 g Mixograph PDR value for flour or gluten may be used to assess flour or gluten bread-making quality. It may be used as a viable alternative to the baking test for the evaluation of the baking potential of flour or gluten, as well as an alternative to currently used ‘gel protein’-based pro-cedures for differentiating between ‘strong’ and ‘extra strong’ wheats.     

Instant Noodles: Processing,Quality, and Nutritional Aspects

Noodles are one of the staple foods consumed in many Asian countries. Instant noodles have become internationally recognized food, and worldwide consumption is on the rise. The properties of instant noodles like taste, nutrition, convenience, safety, longer shelf-life, and reasonable price have made them popular. Quality factors important for instant noodles are color, flavor, and texture, cooking quality, rehydration rates during final preparation, and the presence or absence of rancid taste after extended storage. Microstructure of dough and noodles has been studied to understand the influence of ingredients and processing variables on the noodle quality by employing scanning electron microscopy. Applications of newer techniques like confocal laser scanning microscopy and epifluorescence light microscopy employed to understand the microstructure changes in dough and noodles have also been discussed. Sincere efforts of researchers are underway to improve the formulation, extend the shelf life, and promote universal fortification of instant noodles. Accordingly, many researchers are exploring the potential of noodle fortification as an effective public health intervention and improve its nutritional properties. This review focuses on the functionality of ingredients, unit operations involved, quality criteria for evaluation, recent trends in fortification, and current knowledge in relation to instant noodles.     

Synthesis and luminescent properties of BaLn2(1−x)ZnO5:2xTb3+ (Ln = Y, Gd) nanophosphors

The synthesis of BaLn_2(1?x)ZnO₅:2xTb³⁺ (Ln = Y, Gd) nanophosphors using solution combustion method with an aim to study the effect of sintering temperature and Tb³⁺ ions concentration on the luminescent properties has been investigated. Under UV excitation, BaY_2(1?x)ZnO₅ and BaGd_2(1?x)ZnO₅ nanoparticles exhibit apparent characteristic green emission from ⁵D₄ state to ⁷F_6?3 states of Tb³⁺ ions with the strongest at 544 nm. Luminescence concentration quenching could be observed when the Tb³⁺ ions contents were more than 4 mol% in both nanophosphors. The luminescence decay curves suggest monoexponential behavior of both nanophosphors. X-ray diffraction results confirmed the single-phased orthorhombic structure of both powders belonging to space group Pbnm. TEM analysis indicates the spherical morphology of nanoparticles with average grain size in the range of 85–95 nm. BaY_2(1?x)Tb_2x ZnO₅ and BaGd_2(1?x)Tb_2x ZnO₅ nanophosphors may have potential applications in field emission displays based on their uniform shape, low-cost synthetic route, and diverse luminescent properties.     

Energy transfer and photoluminescent analysis of a novel color-tunable Ba2Y1-xV3O11:xSm3+ nanophosphor for single-phased phosphor-converted white LEDs

Metal nitrates are used to synthesize a series of novel Ba₂Y_1-xV₃O₁₁:xSm³⁺ nanophosphors via urea-assisted solution combustion route. X-ray diffraction (XRD), diffuse reflectance (DR), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy were employed to analyse the structure, morphology, photoluminescent behaviour and energy transfer mechanism. Rietveld analysis over Ba₂Y_0.98Sm_0.02V₃O₁₁ showed that Y³⁺ ions can be well-replaced by trivalent samarium ions without resulting any major alteration in the crystal structure of host lattice. Furthermore, the lattice parameters were determined for both the host as well as the doped composition. The Scherrer equation yielded an average particle size of 44?nm, which in turn was further confirmed by TEM micrographs. The optical band-gap of the host (3.92?eV) was calculated from the diffuse reflectance spectra. Moreover, the photoluminescence spectral studies showed that under near ultra-violet (NUV) excitation of 340?nm, our nanophosphor powder exhibits the characteristic emission peaks of trivalent samarium along with the emission of VO₄^3? (501?nm) group. The excitation energy transfer from vanadate group to Sm³⁺ produced a systematic color tunablity in white region itself. The optimum Sm³⁺ concentration for better luminescence was found to be 2?mol%. The critical distance for energy transfer was calculated to be 29.02?Å, which in turn assisted to shortlist the mechanism responsible for luminescence-quenching (dipole-dipole) arising from the over-doping of the activator. The photoluminescence decay curves revealed the decay kinetics of ⁴G_5/2 electronic state. Finally, the calculation of CIE color coordinates from emission spectra in MATLAB program unveiled a somewhat white-light emitter which may find potential applications in phosphor-converted white light emitting diodes (PC-WLED) under near-ultraviolet (NUV) excitation.     

Sol–gel synthesis,characterization and luminescent properties of Tb doped MLa2O4 (M = Sr or Ba) nanophosphors

Tb³⁺ doped SrLa₂O₄ and BaLa₂O₄ nanophosphors were successfully synthesized via tartaric acid assisted sol–gel method and their luminescent properties were investigated. The crystal structure and morphology of SrLa₂O₄:Tb³⁺ and BaLa₂O₄:Tb³⁺ was studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Thermal decomposition behavior of the dried gels was investigated by thermogravimetry (TG) and differential thermal analysis (TGA). Photoluminescence (PL) behaviors of these nanophosphors were checked by the excitation and emission spectra. These SrLa₂O₄ and BaLa₂O₄ nanophosphors displayed green color under a UV source due to characteristic transition of Tb³⁺ from ⁵D₄ → ⁷F₅ at 544 nm. The dependence of photoluminescence intensity on Tb³⁺ ion concentration, tartaric acid concentration and annealing temperature were also studied in detail. In addition, the optimum doping concentration and time-resolved luminescence spectroscopy were also investigated.     

Technical note: Whole-genome amplification of DNA extracted from cattle semen samples

The bovine genome sequence project and the discovery of many thousands of bovine single nucleotide polymorphisms has opened the door for large-scale genotyping studies to identify genes that contribute to economically important traits with relevance to the beef and dairy industries. Large amounts of DNA will be required for these research projects. This study reports the use of the whole-genome amplification (WGA) method to create an unlimited supply of DNA for use in genotyping studies and long-term storage for future gene discovery projects. Two commercial WGA kits (GenomiPhi, Amersham Biosciences, Sydney, Australia, and REPLI-g, Qiagen, Doncaster, Australia) were used to amplify DNA from straws of bull semen, resulting in an average of 7.2 and 67 μg of DNA per reaction, respectively. The comparison of 3.5 kb of sequences from the amplified and unamplified DNA indicated no detectable DNA differences. Similarly, gene marker analysis conducted on genomic DNA and DNA after WGA indicated no difference in marker amplification or clarity and accuracy of scoring for approximately 10,000 single nucleotide polymorphism markers when compared with WGA samples genotyped in duplicate. These results illustrate that WGA is a suitable method for the amplification and recovery of DNA from bull semen samples for routine genomic investigations.     

Development and characterization of soluble fiber enriched noodles via fortification with partially hydrolyzed guar gum

Partially hydrolyzed guar gum was prepared via enzymatic hydrolysis of native guar gum. Partially hydrolyzed guar gum (PHGG) thus obtained after enzymatic hydrolysis contained 80.04% soluble dietary fiber and 83.1% total dietary fiber. In present study, the effect of process variables such as PHGG level (1–5%), water level (30–40%) and mixing time (2–6 min) on response variables i.e. cooking yield, cooking loss and overall acceptability of noodles were studied using response surface methodology. The second order model obtained for cooking yield, cooking loss and overall acceptability of noodles revealed coefficient of determination of 0.9796, 0.9446 and 0.7787, respectively. The optimum values for independent variables i.e. PHGG level, water level and mixing time were 2.23, 32.03% and 2.81 min, respectively. Results showed that noodles with reduced cooking yield, increased cooking loss and improved sensory and textural characteristics were prepared with fortification of 2.23% partially hydrolyzed guar gum as soluble fibre.