Efficiency analysis of thermosyphon solar flat plate collector with low mass concentrations of ND–Co3O4 hybrid nanofluids: an experimental study

Journal of Thermal Analysis and Calorimetry - In the present study, the thermal efficiency, convective heat transfer and friction factor analysis are investigated for a flat plate solar collector...     

Prediction of thermodynamic and surface properties of Pb−Hg liquid alloys at different temperatures

The thermodynamic properties, such as free energy of mixing, heat of mixing, activity and structural properties, such as concentration fluctuation in long wavelength limit, short-range order parameter of Pb–Hg liquid alloy at 600 K have been calculated using theoretical modelling. It has then been correlated with modified Butler model to compute the surface tension of the alloys at different temperatures. The Pb–Hg system at 600 K is found to be ordering at higher concentration of Pb.     

Probing the quantum critical behavior of CeCoIn5 via Hall effect measurements

We present highly sensitive Hall effect measurements of the heavy fermion compound CeCoIn5 down to temperatures of 55 mK. A pronounced dip in the differential Hall coefficient | partial differential rho(xy)/ partial differential H| at low temperature and above the upper critical field of superconductivity, H(c2), is attributed to critical spin fluctuations associated with the departure from Landau Fermi liquid behavior. This identification is strongly supported by a systematic suppression of this feature at elevated pressures. The resulting crossover line in the field-temperature phase diagram favors a field induced quantum critical point at mu(0)H(qc) approximately 4.1 T below H(c2)(T=0) suggesting related, yet separate, critical fields.     

Flexible carbon nanostructures with electrospun nickel oxide as a lithium-ion battery anode

Carbon nanostructures (CNS) with high electrical conductivity and unique branched structure of carbon nanotubes combined with NiO nanofibers (NFs) were used as anode for lithium-ion batteries. CNS works as a framework substrate for the anodic conversion reaction of nickel oxide (NiO). Electrochemical performance and behavior of CNS/NiO anodes is compared with the conventional carbon (C)/NiO anodes. CNS/NiO NF-based anode retains high specific capacity under different current densities compared to C/NiO anode. Moreover, specific capacity as high as 450 mAh/g for CNS/NiO NF anode is observed compared to only 90 mAh/g for C/NiO NFs using a current density of 500 mA/g after 500 cycles. This improved performance is attributed to the highly conductive network of CNS leading to efficient charge transfer. The high porosity, electrical conductivity as well as the branched and networked nature of CNS reveal to be of critical importance to allow the electrochemical conversion reactions.     

Thermally stimulated discharge current (TSDC) characteristics in β-phase PVDF–BaTiO3 nanocomposites

β-phase polyvinylidene fluoride (PVDF)–BaTiO₃ nanocomposite samples have been prepared by solution mixing method. XRD data represent that the crystallinity of PVDF decreases with increase in loading level of BaTiO₃ nanoparticles. DSC curve represents that the melting point of PVDF is lightly affected by loading concentration of BaTiO₃. The morphology and microstructure of PVDF and PVDF embedded by BaTiO₃ nanofillers were investigated by using inverted contrast microscopy (ICM) and scanning electron microscopy (SEM). FTIR interferrometry is proven that PVDF and BaTiO₃ are not chemically interacting; therefore, interaction of BaTiO₃ is van der Waals type of interaction. The thermally stimulated discharge current (TSDC) of PVDF and PVDF–BaTiO₃ nanocomposites sample was characterized by single peak. The observed TSDC peak is discussed on the basis of dipolar and interfacial polarization.     

Third-order Nonlinear Optical Properties of Octa-substituted Metal-free Phthalocyanine Thin Films

Third-order nonlinear optical susceptibility, χ⁽³⁾ of symmetrically octa-substituted metal-free phthalocyanine thin films measured by the third-harmonic generation technique are reported. The metal-free phthalocyanine has been found to show a χ⁽³⁾ (−3ω; ω,ω, ω) value as large as 7.73×10⁻¹² esu at 1.80 μm. The figure of merit, χ⁽³⁾/α, was estimated to be 4.17×10¹⁷ esu cm at 1.05 μm and 6.97×10¹⁶ esu cm at 1.65 μm. Both linear and third-order optical properties of liquid-crystalline metal-free phthalocyanines are discussed