Hygrothermoelastic response in the bending analysis of elliptic plate due to hygrothermal loading

Abstract

This study investigates the theoretical outline to couple both classical Fourier’s and Fick’s laws to frame a new model of two-temperature hygrothermoelastic diffusion theory for a non-simple rigid material. Based on hygrothermoelasticity method, a system of linearly coupled partial differential equations for the thermal and moisture diffusion for the case of a non-simple medium is established. The transient response using the decoupled technique of a multilayered elliptic plate perpendicular to the axial axis, subjected to hygrothermal loading is considered, to derive closed-form expressions for temperature, moisture, deflection, bending moments, and hygrothermal stresses. The solutions to the governing coupled equations and its boundary conditions are solved by employing a new integral transform technique. The small deflection equation is found and utilized to preserve the intensities of bending moments and stresses, involving the Mathieu functions and its derivatives. Moreover, the elliptical region can be degenerated into a circular part by applying limitations. Numerical results of the transient response of hygrothermoelastic fields are established graphically for the better understanding the underlying elliptic structure, improved understanding of its relationship to circular profile, and better estimates of the effect of the associated hygrothermoelastic responses.     

An exact analytical solution for fractional-order thermoelasticity in a multi-stacked elliptic plate

Abstract

Thermoelastic analysis of an isotropic homogeneous multi-stacked elliptical plate has been considered in this research. For which multi-layered plate is taken into consideration on a plane-parallel elliptic geometry perpendicular to the z-direction. The governing equations are considered in the context of time-fractional derivative of the order α with temperature distribution in each s layer of the stacked plate with time-dependent sectional heat supply on the lower and upper face. The multi-stacked profile consists of s discrete plates each of a different material with perfect thermal contact at each of its s-1 interface. The general solution, which perfectly satisfies the fundamental equation of heat conduction, is obtained using an integral transformation technique. It is solved using a type of quasi-orthogonality relationship by modifying Vodicka’s method and the Laplace transformation. The analysis is based on the small-deflection theory corresponding to the fundamental solutions for the fractional-order heat conduction equation. In addition to this, the intensities of bending moments, forces, maximum normal stresses and its associated stresses are formulated involving the Mathieu functions. As a special case, a multi-stacked circular plate is also discussed in detail as a limiting case. Numerical calculations are also performed, and the results are graphically illustrated.     

Effect of crosslink density on transport of industrial solvents through polyether based polyurethanes

Polyurethanes based on PPG 2000 with variable concentrations of TDI and TMP were prepared and used for sorption studies, employing homologous series of hydrocarbons such as benzene, toluene and xylene. The sorption was observed to be non-Fickian in nature. The solubility parameter of the polyurethane series was observed to be 9·7(calcm^-3)^1/2. The polymer solvent interaction parameter χ was found to be lowest in benzene, suggesting higher interaction with it. The sorption and diffusion coefficients were observed to increase with a decrease in the degree of crosslinking. Molecular weights between crosslinks were calculated using the Flory–Rehner equation and compared with those obtained theoretically. © 1998 Society of Chemical Industry     

Biodiesel production using waste cooking oil: a waste to energy conversion strategy

In this study, biodiesel was produced using waste cooking oil that was discarded as a waste in the environment. The properties of the feedstock were determined using standard ASTM methods. The transesterification process was implemented to extract the biodiesel, and this process was optimized and standardized by selecting three different parameters: molar ratio (methanol:oil), catalyst concentration (KOH) and reaction temperature. The physicochemical properties of the biodiesel so produced were tested and analyzed using gas chromatography. Biodiesel and diesel were mixed in different volumetric ratios, and the exhaust emission characteristics of the blends were determined by testing the blends on a variable compression ratio engine. The study concluded that waste cooking oil has a great potential for waste to energy process. The highest yield of 93.8% was obtained by optimizing the process. Emission characteristics of CO for B50 blend showed a downward trend while NO _x emission was found to be greater for blending ratios above 10%. B10 showed the best results pertaining to lower NO _x and CO emissions.     

Dedicated finite elements for electrode thin films on quartz resonators

The accuracy of the finite element analysis for thickness shear quartz resonators is a function of the mesh resolution; the finer the mesh resolution, the more accurate the finite element solution. A certain minimum number of elements are required in each direction for the solution to converge. This places a high demand on memory for computation, and often the available memory is insufficient. Typically the thickness of the electrode films is very small compared with the thickness of the resonator itself; as a result, electrode elements have very poor aspect ratios, and this is detrimental to the accuracy of the result. In this paper, we propose special methods to model the electrodes at the crystal interface of an AT cut crystal. This reduces the overall problem size and eliminates electrode elements having poor aspect ratios. First, experimental data are presented to demonstrate the effects of electrode film boundary conditions on the frequency-temperature curves of an AT cut plate. Finite element analysis is performed on a mesh representing the resonator, and the results are compared for testing the accuracy of the analysis itself and thus validating the results of analysis. Approximations such as lumping and Guyan reduction are then used to model the electrode thin films at the electrode interface and their results are studied. In addition, a new approximation called merging is proposed to model electrodes at the electrode interface.     

A Cyanine-Bridged Somatostatin Hybrid Probe for Multimodal SSTR2 Imaging in Vitro and in Vivo: Synthesis and Evaluation

Multimodal imaging probes have attracted the interest of ongoing research, for example, for the surgical removal of tumors. Modular synthesis approaches allow the construction of hybrid probes consisting of a radiotracer, a fluorophore and a targeting unit. We present the synthesis of a new asymmetric bifunctional cyanine dye that can be used as a structural and functional linker for the construction of such hybrid probes. ⁶⁸Ga-DOTATATE, a well-characterized radiopeptide targeting the overexpressed somatostatin receptor subtype 2 (SSTR2) in neuroendocrine tumors, was labeled with our cyanine dye, thus providing additional information along with the data obtained from the radiotracer. We tested the SSTR2-targeting and imaging properties of the resulting probe ⁶⁸Ga-DOTA-ICC-TATE in vitro and in a tumor xenograft mouse model. Despite the close proximity between dye and pharmacophore, we observed a high binding affinity towards SSTR2 as well as elevated uptake in SSTR2-overexpressing tumors in the positron emission tomography (PET) scan and histological examination.     

EIS studies on electro-electrodialysis cell for concentration of hydriodic acid

EIS studies were carried out on an electro-electrodialytic cell used for concentration of hydriodic acid using platinum electrodes and nafion117 membrane. Different impedance spectra were obtained where the concentration of iodine was varied while the concentration of HI was kept fixed at 55 wt%. Equivalent circuit model was used to simulate the experimental data and it was found that the impedance of the cell without membrane can be modeled using a single Warburg element along with ohmic resistance in series. This indicates presence of only diffusion transport resistance at the electrode and absence of any non-electroneutral layer. The impedance spectra for cell with membrane can be modeled using a Warburg element and a CPE with capacitive character along with ohmic resistance in series. This indicates formation of a non-electroneutral (heterogeneous transport) layer at the membrane in addition to a diffusion transport layer. It was found that the ohmic resistance increased with increase in the concentration of iodine while the impedances due Warburg and heterogeneous transport layer decreased with increase in iodine concentration.     

Green tea extract: possible mechanism and antibacterial activity on skin pathogens

Camellia sinensis (tea) is known for its therapeutic properties (anti-inflammatory, anti-microbial, anti-tumour, anti-oxidative and anti-ageing). Although, anti-microbial properties of green tea have been studied, its role against bacterial strains related to skin infections and mechanism of action is not well understood. We focussed on exploring anti-microbial activity and the basic mechanism of aqueous green tea leaf extract on selected bacterial strains. Staphylococcus epidermidis, Micrococcus luteus, Brevibacterium linens, Pseudomonas fluorescens and Bacillus subtilis were found to be sensitive to green tea extract via disc diffusion assay (zone of inhibition ≥7 mm). Minimal inhibitory concentration (MIC) was determined via nitro blue tetrazolium (NBT) assay (0.156-0.313 mg/ml). Moreover, the aqueous extract was found to be not toxic to the Vero cell-line up to a concentration of 500 μg/ml. The effect of aqueous extract on adhesion of different bacteria to Vero cells indicated that it inhibits the adhesion at its MIC value.