Thermal conductivity of transparent and flexible polymers containing fillers: A literature review

Enhanced removal of phosphate and nitrate ions from aqueous media using nanosized lanthanum hydrous doped on magnetic graphene nanocomposite.

Hydrothermal synthesis of CuO nanoparticles under near-critical and supercritical conditions was investigated from two different standpoints in the current study. The first standpoint was optimization of “yield”, “purity”, and “size of the nanoparticles” that were optimized at T = 500 °C, time = 2 h, [Cu(NO3)2] = 0.1 mol dm−3, and pH 3. This was achieved by undertaking an orthogonal experiment design methodology and performing different instrumental analyses, such as X-ray diffractometry, inductively coupled plasma spectrometry, and transmission electron microscopy, along with treatment of the data by analysis of variance (ANOVA). The second goal of the study was elucidation of the mechanisms of effects of operational conditions (e.g., temperature) on the above-mentioned target parameters, through application of the appropriate mechanisms of formation of nanoparticles. Nanoparticles are suggested to form initially in the liquid phase as Cu(OH)2, which are later transformed to Cu2(OH)3NO3, through which Cu...

Hydrothermal Synthesis of CuO Nanoparticles: Study on Effects of Operational Conditions on Yield, Purity, and Size of the Nanoparticles

Characterization and bacterial toxicity of lanthanum oxide bulk and nanoparticles

Solubility data of solutes in supercritical fluids (SCF) are crucial for designing extraction processes, such as extraction using SCF or micronization of drug powders. A new empirical equation is proposed to correlate solute solubility in supercritical carbon dioxide (SC CO2) with temperature, pressure and density of pure SC CO2. The proposed equation is ln y2 = J0 + J1P2 + J2T2 + J3 ln ρ where y2 is the mole fraction solubility of the solute in the supercritical phase, J0 − J3 are the model constants calculated by least squares method, P (bar) is the applied pressure, T is temperature (K) and ρ is the density of pure SC CO2. The accuracy of the proposed model and three other empirical equations employing P, T and ρ variables was evaluated using 16 published solubility data sets by calculating the average of absolute relative deviation (AARD). The mean AARD for the proposed model is 7.46 (±4.54) %, which is an acceptable error when compared with the experimental uncertainty. The AARD values for other equations were 11.70 (±23.10), 6.895 (± 3.81) and 6.39 (±6.41). The mean AARD of the new equation is significantly lower than that obtained from Chrastil et al. model and has the same accuracy as compared with Bartle et al. and Mendez-Santiago–Teja model. The proposed model presents more accurate correlation for solubility data in SC CO2. It can be employed to speed up the process of SCF applications in industry.

Prediction of solute solubility in supercritical carbon dioxide: A novel semi-empirical model

In this research, synthesis of lanthanum oxide nanoparticles using supercritical water as a reaction medium in batch type reactor was studied. The crystallographic identity and morphology of the synthesized nanoparticles were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns indicate that the well-crystallized lanthanum oxide nanocrystals can be easily obtained under the current synthetic conditions. The effect of four parameters includes temperature, reaction time; primary concentration of aqueous solution of lanthanum (III) nitrate and pH of starting solution on reaction efficiency, particle size and the BET surface area were investigated using 2 4−1 fractional factorial design. Finally, by employing a regression analysis a model based on effect of significant main variables and their binary interactions was proposed which can predict the percentage of reaction efficiency with acceptable confidence.

Fractional factorial design for the optimization of hydrothermal synthesis of lanthanum oxide nanoparticles under supercritical water condition

This review reports recent advances in the field of thermal conductivity of polymeric nanocomposites. Thermally conductive polymeric nanocomposites can be used for replacing metal parts in several applications, such as liquid cooling and ventilation garment, power electronics, electric motors and generators, heat exchangers, etc., because the polymers have some privileges such as light weight, corrosion resistance, lower manufacturing cost and ease of processing. In this study, the thermal conductivity measurement and modeling of polymeric nanocomposites are discussed in general, and detailed examples are also drawn from the scientific literature. Many theoretical models are available to predict the thermal conductivity of nanocomposites. The simplest of these are mixture rules such as series, parallel, and geometric models. However, the series model typically over predicts the thermal conductivity, whereas the parallel model tends to under predict the thermal conductivity of the nanocomposites. Other models such as the Hamilton-Crosser model and the Lewis-Nielsen model are based on particle size, geometry, and the manner of particle packing in the matrix. Also, there are various effective medium approaches (EMA) like the Maxwell-Garnett (MG) approximation to analyze the thermal transport behaviour in heterogeneous media such as thermal conductivity of some composite structures.

A review on modeling of the thermal conductivity of polymeric nanocomposites

Solubility data of organophosphorous metal extractants in supercritical fluids (SCF) are crucial for designing metal extraction processes. We have developed a new equation of state (EOS) based on virial equation including an untypical parameter as BP/RT, reduced temperature and pressure for prediction of solute solubility in supercritical carbon dioxide (SC CO 2 ). Solubility experimental data (solubility of tributylphosphate in SC CO 2 ) were correlated with the two cubic equations of state (EOS) models, namely the Peng-Robinson EOS (PR-EOS) and the Soave-Redlich-Kwong EOS (SRK-EOS), together with two adjustable parameter van der Waals mixing and combining rules and our proposed EOS. The AARD of our EOS is significantly lower than that obtained from the other EOS models. The proposed EOS presented more accurate correlation for solubility data in SC CO 2 . It can be employed to speed up the process of SCF applications in industry.

Sh. Jafari Nejad

Papers

Prediction of solute solubility in supercritical carbon dioxide: A novel semi-empirical model

Fractional factorial design for the optimization of hydrothermal synthesis of lanthanum oxide nanoparticles under supercritical water condition

A review on modeling of the thermal conductivity of polymeric nanocomposites

A novel equation of state (EOS) for prediction of solute solubility in supercritical carbon dioxide: Experimental determination and correlation