Analysis of structural modifications in γ-irradiated PbO–B2O3–SiO2 glasses by FTIR spectroscopy

The effect of γ-irradiation on the structure of lead borosilicate glasses of varying composition has been probed by FTIR spectroscopy, before and immediately after γ-irradiation. The glasses were irradiated at Calliope ⁶⁰Co plant (RC ENEA Casaccia, Rome), and the spectra were recorded after absorbed doses of 50 Gy, 500 Gy, and 4 kGy. The structural analysis have been made considering both the effect of composition and of irradiation. The experimental results clearly indicate that after irradiation a significant change in structure of borosilicate glass network is observed.     

Determination of the flow stress of five AHSS sheet materials (DP 600, DP 780, DP 780-CR,DP 780-HY and TRIP 780) using the uniaxial tensile and the biaxial Viscous Pressure Bulge (VPB) tests

Room temperature uniaxial tensile and biaxial Viscous Pressure Bulge (VPB) tests were conducted for five Advanced High Strength Steels (AHSS) sheet materials, and the resulting flow stress curves were compared. Strain ratios (R-values) were also determined in the tensile test and used to correct the biaxial flow stress curves for anisotropy. The pressure vs. dome height raw data in the VPB test was extrapolated to the burst pressure to obtain the flow stress curve until fracture. Results of this work show that the flow stress data can be obtained to higher strain values under biaxial state of stress. Moreover, it was observed that some materials behave differently if subjected to different state of stress. These two conclusions, and the fact that the state of stress in actual stamping processes is almost always biaxial, suggest that the bulge test is a more suitable test for obtaining the flow stress of AHSS sheet materials for use as an input to Finite Element (FE) simulation models.     

Combustion synthesis of compounds in the Y2O3-Al2O3 system

In the Y₂O₃-Al₂O₃ system, compounds Y₃Al₅O₁₂ (yttrium aluminum garnet, YAG), YAlO₃ (yttrium aluminum perovskite, YAP), and Y₄Al₂O₉ (yttrium aluminate monoclinic, YAM) are well known. YAG and YAP are of considerable technological importance. Conventional solid-state reaction techniques require high sintering temperatures (above 1800°C) to prepare phase-pure compounds. Though several soft chemical routes have been explored for synthesis of YAG, YAP and YAM, most of these methods are complex. Moreover, phase-pure materials are not obtained in one step and prolonged annealing at temperatures around 1000°C is necessary. In this paper, one-step combustion synthesis of these compounds is reported using a modified procedure and employing mixed (glycine + urea) fuel. Phosphors based on Ce³⁺ activation were also prepared and exhibited characteristic photoluminescence.     

Guest–host interaction in ferroelectric liquid crystal–nanoparticle composite system

The present paper deals with the characterization of a ferroelectric liquid crystal–nanoparticle (FLC–NP) composite system. The dielectric, electrical and polarization property of the FLC–NP composite system have been studied as a function of temperature and frequency. Ferroelectric Cu-doped ZnO (Cu–ZnO) nanoparticles have been added to the pure ferroelectric liquid crystal (FLC) Felix 17/100. The nanoparticles are bigger in size as compared to FLC molecules; therefore, they distort the existing geometry of FLC matrix and set up an antiparallel correlation with the dipole moments of the host FLC molecules. This antiparallel correlation of guest–host geometry reduces the net ferroelectricity of the composite system and modifies all the physical properties of the pure FLC. The change in properties has been analysed and explained in the light of guest–host interaction.     

Morphology optimization for achieving air stable and high performance organic field effect transistors

To develop an all organic active matrix light emitting display required for large area thin display, electronic paper and electronic paints, Si-based thin film transistor has to be replaced with organic thin film transistor (OTFT). The most important issues in OTFT are the low charge carrier mobility and poor stability under ambient conditions, which critically depend on how organic thin films are grown on different substrates. Here we show that both these issues are correlated and can be overcome by certain surface morphology which can only be achieved through anisotropic growth. Careful control of different growth parameters can lead to unprecedented control on thin film morphology which has been shown to be engineered reversibly and reproducibly. High temperature and low evaporation rate increase the diffusive mobility of molecules, which are responsible for the stacking of molecules to higher length scales. By carefully choosing a temperature and evaporation rate, elongated rod-like grains were grown for achieving high performance and stable thin film transistors.     

Fabric-drying process in domestic dryers

A theoretical analysis of the drying process occurring inside the household electric tumbler clothes-dryer is performed to determine various thermo-physical parameters affecting the energy consumption and for the development of a simulation model. Experiments are conducted on a test set-up, based on a compact tumble-dryer, to measure the values of the parameters necessary for evaluating the performance. Widely-accepted economy standards are considered for comparison of simulation and experimental results. The simulation results are in reasonable agreement with experimental data. An empirical correlation for the specific moisture-extraction rate (SMER) is developed to translate energy-consumption information from one standard to the other.     

Effect of aluminium phosphate as admixture on oxychloride cement

The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that aluminium phosphate retards the setting process of the cement and improves water-tightness.     

Plant‐mediated synthesis of silver and gold nanoparticles and their applications

Nanobiotechnology deals with the synthesis of nanostructures using living organisms. Among the use of living organisms for nanoparticle synthesis, plants have found application particularly in metal nanoparticle synthesis. Use of plants for synthesis of nanoparticles could be advantageous over other environmentally benign biological processes as this eliminates the elaborate process of maintaining cell cultures. Biosynthetic processes for nanoparticles would be more useful if nanoparticles were produced extracellularly using plants or their extracts and in a controlled manner according to their size, dispersity and shape. Plant use can also be suitably scaled up for large‐scale synthesis of nanoparticles. In view of this, we have reviewed here the use of plants or their extracts in the synthesis of silver and gold nanoparticles for various human applications. Copyright © 2008 Society of Chemical Industry