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Flow of fluid in nanochannel has been studied by evaluating transverse stress auto-correlation function and shear viscosity of the Ar–Kr and isotopic fluid mixture interacting via Lennard Jones potential. The enhancement in viscosity due to confinement has been investigated for different mass ratios and concentration of one of the fluids in a binary fluid mixture. It has been found that at a given number density and temperature, mixing fluid of lower molar weight reduces the enhancement in viscosity and also lower the chances of freezing of liquid near the walls. We have also studied the effect of concentration of two species on the viscosity. It is found that the enhancement in viscosity is less when the concentration of particles with lighter mass increases.

Quasi-solid-state dye-sensitized solar cells were fabricated using a high molecular polymer redox electrolyte. Poly(ethylene oxide) (PEO) and Poly(vinylidenefluoride-co-hexafluoropropylene) (P(VDF-HFP)) were used to form a stable quasi-solid structure and a three-dimensional gel polymer network structure. The polymer electrolytes were composed of LiI, I₂, and DMPII in the mixture of propylene carbonate (PC) and γ-butyrolactone (GBL) with different volume ratios. A metal-free organic dye (indoline dye D102) was used as a sensitizer. The ionic conductivity of the gel polymer electrolytes was measured with Electrochemical Impedance Spectroscopy (EIS). The dependence of the ionic conductivity on the volume ratio of PC to GBL was investigated. The volume ratio of the mix solvent, weight ratio of PEO/P(VDF-HFP), and the weight ratio of TiO₂ fillers were optimized. The optimized quasi-solid-state cell exhibited an efficiency of 5.49% at full sunlight (air mass 1.5, 60 mW/cm²) irradiation.

The present paper focuses on preparation and process of the magnetorheological (MR) fluid whose carrier fluid is silicone-based oil and its additive is the commercial grease with different concentration of iron particles. General properties of MR fluid are discussed and rheological properties like shear rate, shear stress, viscosity of MR fluid can be found by using cone-and-plate sensor system-type rheometer. The result shows that shear stress as a function of magnetic flux density and viscosity does not strictly scale with iron loading.

In this report, the general validity of the Einstein viscosity relation, ${\eta }_r=1+2.5\phi$, $\phi <0.02({\eta }_r={\eta }_s∕{\eta }_0$, ratio of solution to solvent viscosity), is examined in nanofluids where monodisperse spherical nanoparticles (polystyrene latex spheres) of size 50–400nm were dispersed in water at room temperature, 25${}^{\circ }$C. In addition to viscosity, we also measured contact angle, $\theta$, and surface free-energy, $U$, as function of particle concentration and observed that the universal relation $X_r=1+X\phi$, $\phi <0.02$, remained valid, where $X_r$ may be relative viscosity, contact angle or surface free-energy and $X$ is a shape-dependent constant and is 2.5 in the Einstein limit. Thus, the Einstein relation has a wider validity than is generally thought encompassing both bulk and surface properties of nanofluids. Furthermore, we extend the study to establish an empirical relation between intrinsic viscosity [$\eta$] and Huggins interaction parameter $k_H$, with particle size $D$, which obeyed: $[\eta ]$ or $k_H=a+\frac{b}{D}+\frac{c}{D^2}$, where $D$ is in nm, [$\eta$] is in cc/g, $k_H$ is in (g/cc)² and $a$, $b$ and $c$ are constants of particle size. Identical expressions could be established for contact angle and surface free energy. These remarkable observations have not been reported hitherto.

The aim of this study is the numerical computation of the wave propagation in crack geological solids. The finite difference method was applied to solve the differential equations involved in the problem. Since the problem is symmetric, we prefer to use this technique instead of the finite element method and/or boundary elements technique. A comparison of the numerical results with analytical solutions is provided.

This work aimed to study the photo disruptive effect of a Q-switched Nd:YAG laser with two different energy protocols on the rheological properties of the vitreous humor after treatment of posterior vitreous detachment (PVD). Twenty-one New Zealand albino rabbits were used in this study and divided into three groups. One group was used as control (n = 6 eyes), the second group (n = 18) was treated with Q-switched Nd:YAG laser energy of 5 mJ × 100 pulse (× means times) delivered to the anterior, middle and posterior vitreous respectively (n = 6 eyes for each). The third group (n = 18 eyes) was treated with 10 mJ × 50 pulse delivered to the anterior, middle and posterior vitreous respectively (n = 6 eyes for each). After two weeks, the protein content, refractive index (RI) and the rheological properties of vitreous humor were determined. The protein content, refractive index, consistency, shear stress and viscosity were increased especially for irradiation of the mid-vitreous, and posterior vitreous. The flow index remained below unity indicating the non-Newtonian behavior of the vitreous humor. Application of Q-switched Nd:YAG laser on mid-vitreous and posterior vitreous induce deleterious effect on the gel state of the vitreous humor.

The influence of particle size on density, ultrasonic velocity and viscosity of magnetite nanofluids have been determined at (298.15 K, 303.15 K, 308.15 K and 313.15 K). Two different sized nanoparticles (commercially procured D = 20–30 nm and synthesized D = 9 ± 3 nm in the laboratory by co-precipitation method) were dispersed in a citric acid base fluid. The desired parameters have been experimentally determined by loading different concentrations of nanoparticles. It has been found that the influence of particle size and temperature on measured physical parameters (density, ultrasonic velocity and viscosity) is not negligible and can also be taken into account in any practical application. The analyzed physical parameters can describe qualitatively and quantitatively the particle size distribution of nanofluids at a specific temperature. Results are interpreted in terms of particle–particle and particle–fluid interactions.

In the present study, the effect of particle concentration, particle diameter and temperature on the thermal conductivity and viscosity of Al₂O₃/water nanofluids was investigated experimentally using design of experiment approach (full factorial design). Variables were selected at two levels each: particle concentration (0.1–1%), particle diameter (20–40nm) and temperature (10–40${}^{\circ }$C). It was observed that the thermal conductivity of the Al₂O₃/water nanofluids increases with increasing concentration and temperature and decreases with increase in particle diameter, while viscosity increases with increasing particle diameter. Results showed that the interaction effect of concentration and temperature also has significant effect on the thermal conductivity of Al₂O₃/water nanofluids. For viscosity, the interaction of particle diameter and temperature was important. Utility concept was used to optimize the properties collectively for better heat transfer performance. The optimal combination for high thermal conductivity and low viscosity was obtained at higher level of particle concentration (1%), lower level of particle diameter (20nm) and higher level of temperature (40${}^{\circ }$C). At this condition the increment in thermal conductivity and viscosity compared to base fluid was 11.51% and 6.37%, respectively.

The aim of this study is to investigate the rheological properties of three grades of virgin bitumen 40/50pen, 60/70pen and 80/100pen using the frequency sweep strain control. Several road pavement distresses are related to rheological properties of bitumen. Rutting and fatigue cracking are the major distresses that lead to permanent failures in pavement construction. There is thus growing demand for the study the rheological properties of bitumen using high accuracy device such as Dynamic Shear Rheometer (DSR). Frequency sweep strain controlled test and penetration test has been conducted to investigate the rheological properties of the three grades of bitumen. The results shows that value of G*, G′, G″ and the viscosity are higher in harder bitumen and its match with the penetration tests results.