Size-dependent generalized thermoelasticity model for Timoshenko microbeams

A size-dependent, explicit formulation for coupled thermoelasticity addressing a Timoshenko microbeam is derived in this study. This novel model combines modified couple stresses and non-Fourier heat conduction to capture size effects in the microscale. To this purpose, a length-scale parameter as square root of the ratio of curvature modulus to shear modulus and a thermal relaxation time as the phase lag of heat flux vector are considered for predicting the thermomechanical behavior in a microscale device accurately. Governing equations and boundary conditions of motion are obtained simultaneously through variational formulation based on Hamilton’s principle. As for case study, the model is utilized for simply supported microbeams subjected to a constant impulsive force per unit length. A comparison of the results with those obtained by the classical elasticity and Fourier heat conduction theories is carried out. Findings indicate that simultaneous considering the length-scale parameter and thermal relaxation time has strong influence on the thermoelastic behavior of microbeams. In dynamic thermoelastic analysis of the microbeam, while the non-Fourier heat conduction model is employed, the modified couple stress theory predicts larger deflection compared with the classical theory.     

Effect of binder liquid type on spherical crystallization

Aim: Spherical crystallization is a process of formation of agglomerates of crystals held together by binder liquid. This research focused on understanding the effect of type of solvents used as binder liquid on the agglomeration of crystals.

Method: Carbamazepine and ethanol/water were used respectively as a model drug and crystallization system. Eight solvents as binder liquid including chloroform, dichloromethane, isopropyl acetate, ethyl acetate, n-hexane, dimethyl aniline, benzene and toluene were examined to better understand the relationship between the physical properties of the binder liquid and its ability to bring about the formation of the agglomerates. Moreover, the agglomerates obtained from effective solvents as binder liquid were evaluated in term of size, apparent particle density and compressive strength.

Results: In this study the clear trend was observed experimentally in the agglomerate formation as a function of physical properties of the binder liquid such as miscibility with crystallization system. Furthermore, the properties of obtained agglomerates such as size, apparent particle density and compressive strength were directly related to physical properties of effective binder liquids.

Conclusion: Results of this study offer a useful starting point for a conceptual framework to guide the selection of solvent systems for spherical crystallization.     

A novel architecture for improving slew rate in FinFET-based op-amps and OTAs

A new architecture for improvement of slew rate (SR) of an op-amp or an operational transconductance amplifier (OTA) in FinFET technology is proposed. The principle of operation of the proposed architecture is based on a set of additional current sources which are switched on, only when OTA should provide a high current, usually for charge or discharge of large load capacitor. Therefore, the power overhead is less compared to conventional high SR designs. The commonly used two-stage Miller-compensated op-amp, designed and optimized in sub 45 nm FinFET technology with 1 V single supply voltage, is used as an example for demonstration of the proposed method. For the same FinFET technology and with optimal design, it is shown that the slew rate of the op-amp is significantly improved. The slew rate is improved from 273 to $5590\mathrm{V}/\mathrm{\mu }\mathrm{s}$ for an input signal with a rise time of 100 ps. The other performance measures such as gain and phase margin remain unchanged with the additional circuitry used for slew rate enhancement.     

Socio-spatial interactions of a cluster-house concept apartment in mehr als wohnen project in Zurich,Switzerland

This article explores the socio-spatial interactions of a micro-community in a cluster-house concept apartment.The apartment has been designed for retreat and c...     

Influence of carrier particle size, carrier ratio and addition of fine ternary particles on the dry powder inhalation performance of insulin-loaded PLGA microcapsules

The effects of carrier particle size, carrier ratio and addition of fine ternary agents on dry powder inhalation performance of insulin-loaded PLGA microcapsules were investigated. The use of mannitol with larger particle size in the lower carrier/microcapsules ratio led to higher deposition profiles of the drug. The fine spray dried mannitol and spray dried leucine as the ternary agents both decreased the deposition and dispersibility of microcapsules. It was concluded that addition of ternary component does not always improve aerosolization properties of DPI formulations. Carrier particle size, its flowability and carrier-drug ratio were shown to play an important role in DPI formulations.     

Quality changes of fish burgers prepared from deep flounder (Pseudorhombus elevatus Ogilby, 1912) with and without coating during frozen storage (−18 °C)

In the present study, chemical and sensory qualities of fish burgers prepared from deep flounder (Pseudorhombus elevatus Ogilby, 1912) with and without coating (Group A and Group B, respectively) or batter and breading materials were determined during frozen storage at ?18 °C for 5 months. According the statistical results, Total volatile base nitrogen of two groups increased significantly (P < 0.05) but a significant decrease (P < 0.05) was observed at the third month for Group A. Thiobarbituric acid value of Group A decreased significantly (P < 0.05) with the storage time from 1.01 to 0.22, whereas a significant increase (P < 0.05) was observed for Group B from 0.15 to 0.62 at the end of storage time. There were significant differences of pH in either the Group A or Group B between the beginning and end of the storage periods (P < 0.05). Parameters of colour, texture, taste and general acceptability for two groups decreased (P < 0.05) but Group B indicated better scores than Group A at the end of the storage period.     

Hydrodynamic and thermal performance prediction of functionalized MWNT-based water nanofluids under the laminar flow regime using the adaptive neuro-fuzzy inference system

ABSTRACT

Adaptive Neuro-Fuzzy Inference System (ANFIS) opens a new gateway in understanding the complex behaviors and phenomena for different fields such as heat transfer in nanoparticles. The ANFIS method is a shortcut to find a nonlinear relation between input and output and results in valid outcomes, especially in engineering phenomena, which is used here for determining the convective heat transfer coefficient. Using the ANFIS, the critical parameters in heat transfer including convective heat transfer coefficient and pressure drop are determined. To realize this issue, the thermophysical properties of non-covalently and covalently functionalized multiwalled carbon nanotubes-based water nanofluid were investigated experimentally. The results of simulation and their comparison with the experimental results showed an excellent evidence on the validity of the model, which can be expanded for other conditions. The proposed method of ANFIS modeling may be applied to the optimization of carbon-based nanostructure-based water nanofluid in a circular tube with constant heat flux.     

Synthesis of zeolites NaA and analcime using rice husk ash as silica source without using organic template

Silica was extracted from Fajr rice husk ash (RHA) with approximately 97% purity, converted to sodium and potassium silicate solutions and used as silica source for the synthesis of NaA and analcime zeolites. NaOH and KOH without organic templates were used in the synthesis of NaA and analcime zeolite, respectively. Conventional heating and microwave-assisted hydrothermal were used in zeolite synthesis. Zeolites were characterized with XRD, SEM and IR spectroscopy. Heating time and Si/Al ratio were optimized for the synthesis of zeolites.     

Springback in acetylated wood based composites

Reasons of the strength loss of the acetylated wood based composites were still under question. This research was considered to study springback in the acetylated particleboard and the medium density fibreboard. Chips and fibres were acetylated by using the acetic anhydride to gain different percentages of the weights (WPG). The boards were made based on the target thicknesses. Thickness of the boards as well as the modulus of elasticity (MOE) and the modulus of rupture (MOR) were determined after conditioning based on three point static bending test.Results showed that the moisture content and the thickness swelling of the boards were reduced as the WPG was increased. However, increase of the springback and reduction of the MOE and the MOR were revealed as the WPG increased in the test boards after condition. It was also revealed that the springback was correlated with the weight gain and increased as the WPG was raised in the test boards. Reduction of the MOE and the MOR was also correlated with the springback in the test boards.