Effect of heat treatment on thermal and mechanical stability of NaOH-doped xanthan gum-based hydrogels

Journal of Solid State Electrochemistry - Xanthan gum (XG)-based hydrogels containing sodium hydroxide (NaOH) salt were synthesized with the use of distilled water (DW) at room temperature and...     

Stability and dynamic analysis of partially cracked thin orthotropic microplates under thermal environment: an analytical approach

Abstract

An analytical model is proposed to analyze the vibration and buckling problem of partially cracked thin orthotropic microplate in the presence of thermal environment. The differential governing equation for the cracked plate is derived using the classical plate theory in conjunction with the strain gradient theory of elasticity. The crack is modeled using appropriate crack compliance coefficients based on the simplified line spring model. The influence of thermal environment is incorporated in governing equation in form thermal moments and in-plane compressive forces. The governing equation for cracked plate has been solved analytically to get fundamental frequency and central deflection of plate. To demonstrate the accuracy of the present model, few comparison studies are carried out with the published literature. The stability and dynamic characteristics of the cracked plate are studied considering various parameters such as crack length, plate thickness, change in temperature, and internal length scale of microstructure. It has been concluded that the frequency and deflection are affected by crack length, temperature, and internal length scale of microstructure. Furthermore, to study the buckling behavior of cracked plate, the classical relations for critical buckling load and critical buckling temperature is also proposed considering the effect of crack length, temperature, and internal length scale of microstructure.     

Qualitative analysis of an integro-differential equation model of periodic chemotherapy

An existing model of tumor growth that accounts for cell cycle arrest and cell death induced by chemotherapy is extended to simulate the response to treatment of a tumor growing in vivo. The tumor is assumed to undergo logistic growth in the absence of therapy, and treatment is administered periodically rather than continuously. Necessary and sufficient conditions for the global stability of the cancer-free equilibrium are derived and conditions under which the system evolves to periodic solutions are determined.     

Stability-Indicating HPTLC Method for Simultaneous Estimation of Amlodipine Besylate,Hydrochlorothiazide and Olmesartan Medoxomil in Combined Tablet Dosage Forms

JPC – Journal of Planar Chromatography – Modern TLC -     

Thermal stabilities of delithiated olivine MPO4 (M = Fe,Mn) cathodes investigated using first principles calculations

We present an analysis of the thermal reduction of delithiated LiMnPO₄ and LiFePO₄ based on the quarternary phase diagrams as calculated from first principles. Our results confirm the recent experimental findings that MnPO₄ decomposes at a much lower temperature than FePO₄, thereby potentially posing larger safety issues for LiMnPO₄ cathodes. We find that while substantial oxygen is released as MnPO₄ reduces to Mn₂P₂O₇, the mixed valence phases that form in the decomposition process of FePO₄ limit the amount of oxygen evolved.     

Synthesis and properties of CdSe Quantum Dot sensitized ZnO nanocomposites

In this work, zinc oxide nanocrystals with an average particle size of 13–22 nm are readily synthesized in aqueous medium by the wet synthesis method. Different sized nanocrystals obtained with change in calcination temperature are characterized by PL photoluminescence (PL) and UV–vis absorption spectroscopies, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The average crystal size of the as prepared ZnO nanopowder is determined by XRD and was found to be in good agreement with the UV–vis absorption analysis. The quality of different ZnO nanopowders is confirmed by XRD spectra. On the basis of different characterizations, ZnO calcined for 1 h (due to its large size and less agglomeration) is chosen for synthesis of ZnO–CdSe nanocomposites with variable sized CdSe QD's (Quantum Dots). Nano-composites are synthesized using bifunctional linker molecule Mercaptopropionic Acid (MPA), and by directly adsorbing CdSe QD's over the surface of ZnO nanocrystals. The difference in charge transfer mechanism in ZnO–CdSe nanocomposites due to different crystallite size of CdSe QD's is studied. Higher crystallinity of ZnO–CdSe nanocomposites can be determined from XRD characterization. Size and mode of attachment in various ZnO–CdSe nanocomposites are determined by SEM studies.