[en] The study of alkaline earth doped stannate ceramics of Barium and Calcium is being carried out to explore more on the phosphorescent applications. The present study is an energy and cost-efficient green approach towards the preparation of Europium (III) doped stannate of Calcium and Barium in the nano sca leas it involves the biowaste of egg shell as a precursor for calcium carbonate and the plant extract of aloe vera as the reaction medium and a comparatively lower calcination temperature than reported so far. The structure, phase purity, surface morphology and applications in terms of photo luminescence, photo catalytic and anti-microbial activities have been investigated. The doping of alkaline earth metal of Europium in lower weight percentage(lesser than one) was carried out at lower processing temperatures than reported earlier. There was a phase transition in the case of barium stannate upon doping and there were observable changes in crystallite size, morphology and microstructure in the case of Stannates of Calcium and Barium. The results of photo luminescence study and the photo catalytic degradation of methylene blue dye were encouraging. The anti-microbial study in terms of toxicity of the doped samples in smaller dosages upon Pseudomonas aeruginosa, Staphylococcus aureus provided a new dimension to their application. (author)

[en] In the present investigation the material Co₃O₄ nanoparticles were prepared by co-precipitation method, while graphitic carbon nitride (g-C₃N₄) was prepared by direct heating of melamine. The nanocomposite g-C₃N₄-Co₃O₄ were prepared by stoichiometric mixing and direct heating in porcelain boat followed by calcination. The prepared nanomaterials were characterized by various techniques. These both materials were characterized by XRD to get structural parameters and to confirm the average particle size of prepared nanomaterial. The scanning electron microscopy (SEM) was carried out to get surface characteristics of prepared materials. The energy dispersive spectroscopy was conducted to get elemental composition prepared material Co₃O₄ and g-C₃N₄-Co₃O₄. The transmission electron microscopy (TEM) was conducted to get lattice information of prepared material. While magnetic properties of both the material were investigated by means of vibrating sample magnetometer (VSM), since cobalt oxide is a ferromagnetic material. The surface area was confirmed from Brunauer-Emmett-Teller (BET) study. The g-C₃N₄-Co₃O₄ nanocomposite has found enhanced surface area of 78.48 m²/g in comparison to the sole Co₃O₄ nanomaterial (55.23 m²/g). Both these prepared materials were utilized in photocatlytic degradation of Carbol Fuchsin (CF) dye. The various parameters related to optimization of photocatlytic degradation of dyes were investigated in detail. The carbon nitride mediated cobalt oxide material is found to be very effective for degradation of CF dye and almost 97% of dye was successfully decomposed by the g-C₃N₄-Co₃O₄ nanocomposite. The reusability test confirms that the prepared g-C₃N₄-Co₃O₄ nanocomposite is very efficient in degradation of CF dye in multiple cycles with 110 minutes of contact time. (author)

[en] Low temperature solution combustion synthesized Cr³⁺(1-4 mol%) doped Mg₂SiO₄ nanoparticles were analyzed by Powder X-ray Diffraction (PXRD), Fourier Transform Infra-Red (FTIR) spectroscopy, Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) techniques. PXRD profile shows the samples are crystalline. FTIR spectra show MgO₆ octahedral and Si-O bending and stretching modes. It was observed that, CV show excellent semi rectangular shaped voltammograms due to the oxidation reduction reactions and the reversibility of the reaction which suits for electric double layer capacitance. Charge transfer resistance (R_ct) was found to be 10 Ω indicates the better electron transfer from one phase to another. (author)

[en] Often newer practical materials and devices, with huge economic gains, have resulted from commercialization of suitable selections of latest research on materials and their applications. Spread of laboratory discoveries of semiconductors and their properties to practical applications in every sphere of life and industry is the easiest example. Present work will focus on a few random examples of newer materials science research topics that is, or may possibly be, commercially exploited. Piezoelectric (PE) materials including High Temperature (HT) PE materials will be outlined for industry to explore novel applications ranging from ultrafine manipulation to heavy duty drilling and making PE sensors, actuators and ultrasonic devices. Higher electrical conductivity of a defect form of II=VI oxides (Cd-O in particular) is highlighted for possible practical exploitations. For 2^nd generation Electromagnetic Interference (EMI) Shielding, polymeric composites with either newer absorbing agents or newer reflecting agents or their mixtures will be outlined. Novel Fe- or Ni- based HTSCs (high temperature superconductors) are less anisotropic and rather metallic in contrast to Cu-oxide HTSCs. So, these offer added advantage for making superconducting electrical cables. A balanced presentation of these potentially usable materials and their basic physics will be attempted. (author)

[en] Graphene is a material that has superior mechanical, electrical, and thermal properties. It has drawn the attention of many the scientific researchers for this purpose. In this paper, three different types of fillers, GNPs, MWCNTs and EG reinforced epoxy nanocomposites were mainly studied. Different shear mixing speeds and shear mixing times were considered during the study of the nanocomposites with 0.1 wt% loading of the fillers. The effects of various types of fillers and different shear mixing speeds and durations on mechanical and electrical properties of the final composites were examined. The GNPs-reinforced epoxy nanocomposite was the only one that showed a 13% improvement in elastic modulus as compared to pure epoxy when the shear mixing conditions were 3000 rpm for 2 hours. The research also studied the effects of different loadings of GNPs and the addition of acetone as a solvent on the final mechanical, electrical and thermal properties of the composites (with the fixed shear mixing speed and time). The tensile strength of the composites reduced drastically when the loading of GNPs increased while the elastic modulus shows some increase with the growth in GNP loading. The study found that GNPs reinforced composites did not show the percolation threshold even with 5 wt% (with the ratio to the weight of epoxy) loading of the GNPs. The GNPs-reinforced epoxy composites showed an 116% improvement in the thermal conductivity as compared to the pure epoxy samples when the GNPs loading was 5 wt%. The results from the studied literatures also showed that the samples prepared with the addition of acetone had higher thermal diffusivity than the samples prepared without acetone. (author)

[en] WLEDs were the potential materials for significantly improving lighting efficiency, resulting in reduction of the excitation energy and also reduction in pollution from fossil fuel power plants. To enhance the quality of white light, the researches on single-component phosphor are very much essential. Green light emitting phosphors are widely used in solid state lighting technology. Tb³⁺ ions are doped into different hosts and they are excited by UV or NUV light to emit green light. This review presents, different hosts like silicates, oxides, phosphates and titanates based Tb³⁺ ions doped phosphor. Attempts were made to analyse preparation technique and photoluminescence characteristics of phosphors. Finally potential material among selected materials is identified for light emitting display device applications. (author)

[en] In the present study, cobalt sulphide was successfully synthesised via a simple, one-step hydrothermal route. The material has been characterised via infrared (FTIR) spectroscopy, electron microscopy (FESEM), and X-ray diffraction (XRD). The FTIR spectrum reveals a peak at 1126 cm^-1, which corresponds to the S-O bending mode, and a peak at 663 cm^-1, which represents sulphide stretching. According to XRD analysis, cobalt sulphide formed with the CoS1.097 configuration. FESEM study reveals that cobalt sulphide hexagonal sheets with a thickness of less than 100 nm have been prepared that are further arranged in a floral pattern. Cobalt and sulphide concentrations were found to be proportional in EDX analyses. Further, Electrochemical testing was performed with a two-electrode setup, 6M KOH as the electrolyte, and various current collectors (including nickel foam and aluminium foil). The galvanostatic charge-discharge characteristics and capacitance values have been compared using impedance spectroscopy and other techniques. Details of the analysis are presented. (author)

[en] We have reviewed recent progress on various types of humidity sensors as it is one of the most significant issues in various areas of sensing appliances such as instrumentation, charge storage automated systems, industries and agriculture. Various effective approaches have been discussed to develop ceramic, semiconducting and polymer based graphite sensors. It was found that graphite based nanocomposite materials have unique potential for detecting humidity due to specific structure, high electro thermal conductivities, good mechanical properties, low cost and ultrahigh surface area that increases applications in the field of energy storage devices. (author)

[en] History of superconductivity has seen a series of sudden surprises. 1^st surprise is the discovery of superconductivity itself, by Prof. Heike Kamerlingh Onnes in Leiden, Holland, in 1911, with his clarification in 1913. Our journey will take us finally to the very surprising discovery (2008) and subsequent study of superconductivity in magnetic materials like BaFe₂ As₂ popularly known as iron superconductors. Many materials loose electrical resistance, R, completely, and expel all magnetic flux from inside on cooling it below what is called (superconducting) critical temperature (T_c) - under certain magnetic field, H, and current density, J. That infinitely conducting state is called the superconducting state, and the phenomenon is called Superconductivity. Using H > H_c or J > J_c will also destroy the superconducting state – with H_c and J_c being called (superconducting) critical field and (superconducting) critical current density, respectively. In fact, T_c is a function of H and J. A Type II superconductor allows, above H_c1 (the Lower Critical Field) and below H_c2 (the Upper Critical Field), magnetic flux to pass through the superconductor in form of flux tubes that are in normal state within the superconducting surrounding Applying a field H > H_c2, destroys the superconducting state. In general, H_c2 of Type II superconductors far exceed H_c of Type I superconductors. Type II has higher J_c too. Practical superconducting wires and tapes are, therefore, invariably made from Type II superconductors

[en] This review paper mainly focuses on the processing technique of carbon nanotube reinforced materials with light material matrix composites of the powder metallurgy route. Different mixing/alloying conditions are used for carbon nanotube dispersion (CNT) in the Aluminium matrix using a ball milling process with ball milling time, milling speed, Ball to powder (BPR) ratio, and Process control agent (PCA). Processing parameters are discussed, such as sintering temperature, sintering time, pressure, and heat treatment condition. Mechanical and microstructural properties are discussed. (author)