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Busby G.A.,University of Strathclyde | Grant M.H.,University of Strathclyde | MacKay S.P.,Strathclyde Institute of Pharmacy and Biomedical science | Riches P.E.,University of Strathclyde | Riches P.E.,Advanced Materials Research Laboratory
Journal of Biomechanics | Year: 2013

Reconstituted collagen hydrogels are often used for in vitro studies of cell-matrix interaction and as scaffolds for tissue engineering. Understanding the mechanical and transport behaviours of collagen hydrogels is therefore extremely important, albeit difficult due to their very high water content (typically >99.5%). In the present study the mechanical behaviour of collagen hydrogels in confined compression was investigated using biphasic theory (J Biomechemical Engineering 102 (1980) 73), to ascertain whether the technique is sufficiently sensitive to determine differences in the characteristics of hydrogels of between 0.2% and 0.4% collagen. Peak stress, equilibrium stress, aggregate modulus and hydraulic permeability of the hydrogels exhibited sensitivity to collagen content, demonstrating that the technique is clearly able to discriminate between hydrogels with small differences in collagen content and may also be sensitive to factors that affect matrix remodelling. The results also offer additional insight into the deformation-dependent permeability of collagen hydrogels. This study suggests that confined compression, together with biphasic theory, is a suitable technique for assessing the mechanical properties of collagen hydrogels. © 2012 Elsevier Ltd.

Michael Raj F.,Advanced Materials Research Laboratory | Celine Rose I.R.,Advanced Materials Research Laboratory | Sathish R.,CECRI | Jeya Rajendran A.,Advanced Materials Research Laboratory
Journal of Chemical and Pharmaceutical Sciences | Year: 2015

Cadmium oxide nanoparticles were prepared by precipitation method using cadmium acetate and ammonia solution. The synthesized CdO nanoparticles were characterized by using FTIR, X-ray diffraction studies (XRD), Field emission scanning electron microscopy (FE-SEM), Energy dispersive spectrometry (EDS), BET analysis, I-V characterisitics and dielectric studies. FTIR analysis confirmed the Cd-O bond formation in synthesized nanomaterial. The X-ray diffraction pattern revealed that synthesized cadmium oxide nanoparticles are face centered cubic with average crystallite size of 25 nm. The morphology and elemental composition were confirmed by FE-SEM and EDAX.The synthesized CdO nanoparticles showed high surface area of 31.5 m2/g, which enables high absorption of dye molecule in DSSC fabrication for increasing the efficiency of solarcell. The temperature and frequency dependence of dielectric constant, dielectric loss and AC conductivities were studied over a range of (50 Hz to 5 MHz) and temperature (40-200°C). Solar cell was fabricated using CdS as photo cathode material, TiO2/CdO as photo anode material, potassium iodide/iodine as electrolyte solution, ruthenium red dye as sensitizer and solar conversion efficiency was found to be 1.62%.

Srinivas A.,Advanced Magnetics Group | Krishnaiah R.V.,Advanced Magnetics Group | Niranjani V.L.,Advanced Magnetics Group | Kamat S.V.,Advanced Magnetics Group | And 2 more authors.
Ceramics International | Year: 2015

Barium zirconate titanate-barium calcium titanate [(0.5)BZT-(0.5)BCT], a solid solution ceramic, was synthesized by solid state route and its structure, microstructure, dielectric, ferroelectric, piezoelectric and mechanical properties were investigated. Unipolar and bipolar strain loops with minimal hysteresis were observed from strain measurements. The d33 ∗ values increased with increase in electric field, reached a maximum of 1257 pm/V at a field of 0.6 kV/mm, subsequently decreased to 530 pm/V at a field of 4.1 kV/mm and showed slim hysteresis. A high value of dielectric constant (εr~9700) was recorded with the variation of frequency at a temperature around 85 °C (Tc) indicating frequency independent transition. P vs. E and I vs. E hysteresis measurements confirmed the intrinsic ferroelectric character with Pr of ~9.1 μC/cm2 and EC of ~0.3 kV/mm. Polarization vs. electric field measurements at different electric fields showed slim and saturated hysteresis behaviour indicating a coarse grain structure. In the synthesized (0.5)BZT-(0.5)BCT, Vickers hardness, Young's modulus and fracture toughness were evaluated, and compared with those of lead based compounds and were found to be on par with them. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Nafari Q. M.,AMR of Technology | Abbasi S.M.,Advanced Materials Research Laboratory
Transactions of the Indian Institute of Metals | Year: 2013

The effects of composition, specially the Cu element and thermomechanical training process on the transformation and one way shape memory behavior (OWSM) of NiTi based alloys were investigated using differential scanning calorimetry and microstructural analysis. The hot rolled strips with different compositions were trained under various applied pre-strains by bending test at martensitic state. It was found that the presence of Cu in the NiTi alloy results in an improvement of the OWSM effect by reducing the transformation hysteresis and forming the longer martensitic variants with lower interfacial energy than the NiTi binary alloys. Increasing the applied pre-strain and the number of thermomechanical training cycles caused OWSM effect to decrease. Although the transformation temperature increased at the higher applied pre-strain, it was reduced during the thermomechanical training process. © 2013 Indian Institute of Metals.

Celine Rose I.R.,Advanced Materials Research Laboratory | Sathish R.,CSIR - Central Electrochemical Research Institute | Jeya Rajendran A.,Advanced Materials Research Laboratory | Sagayaraj P.,Loyola College
Journal of Materials and Environmental Science | Year: 2016

Cadmium selenide nanoparticles were synthesized by solvothermal method using cadmium acetate, Cd(CH3COO)2 and selenous acid (H2SeO3) at 60°C, and at different reaction times of 4, 8,12 and 16 hours. The synthesized nanoparticles were characterized by XRD, UV, PL, Raman, SEM and EDX spectral analysis. X-ray diffraction analysis confirmed a hexagonal, wurtzite structure and grain sizes were found to be of 15.8, 10.5, 6.7 and 111.7nm at 4, 8, 12 and 16 hours respectively. The absorption and photoluminescence spectra of the CdSe nanoparticle showed a red shift as the particle size was reduced. The band gap energy was computed from the absorption data and was found to be 1.62, 1.76, and 1.8 eV for 4, 8 and 12 hours reaction time respectively. The dielectric constant, dielectric loss, and conductivity of CdSe nanoparticles were studied over a range of frequency (50 Hz - 5 MHz) and temperature (40°C-140 °C). Both dielectric constant and dielectric loss decreased with the increase in frequency and temperature. A solar cell was fabricated using TiO2 as a photo anode, CdSe as a counter electrode, alizarine dye as sensitizer and I-/I3-as electrolyte, and the maximum conversion efficiency of the solar cell was found to be 3.28 %.

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