Over the most recent couple of decades, tremendous consideration is drawn towards photovoltaic–thermal systems because of their advantages over the solar thermal and PV applications. This paper intends to show different electrical and thermal aspects of photovoltaic–thermal systems and the researches in absorber design modification, development, and applications. From the previous review articles, it has been concluded that the heat energy exhausted from the PV module can be further utilized in different ways and helps in achieving better efficiency. Furthermore, the types of photovoltaic–thermal systems such as air collector, water collector, and combi system, coupling with heat pump and their application to buildings are also stated. This paper also discussed certain design aspects like modifications in the flow channel by adding fins, thin metallic sheets, roll-bond absorber, and porous media and the effect of these modifications on the hybrid system’s efficiency. Furthermore, the use of the latest technologies such as nanofluids, thermoelectric generators, and phase-change materials improves the overall system performance. The role of soft-computing techniques is forecasting the impact of various parameters on the photovoltaic–thermal system is also discussed.

We report the concentration dependent Raman spectra of neat dimethyl sulfoxide [(CH 3 ) 2 SO, DMSO] and its binary mixtures with water (W)/methanol (M) in both n(SLO) and n(C-H) regions. The n(SLO) line profile of neat DMSO was resolved into four component peaks at 1036, 1044, 1054 and 1064 cm 21 and assigned to different dimeric species of neat DMSO. A careful analysis of the Raman spectra of DMSO with water in the n(SLO) region at different concentrations reveals that upon dilution, an additional peak is observed at 1017 cm 21 (lower side of the peak~1036 cm 21 ) which is attributed to the hydrogen bonding of DMSO with water. For the highest dilution case (x = 0.1 of DMSO), hydrogen bonded species and symmetric stretching of the dimeric n(SLO) mode were obtained which suggest that DMSO exists in dimer form even at low concentration of DMSO. The significant blue shifting of the C-H frequency due to C-H … O hydrogen bonding was also obtained in the case of both solvents. Our experimental results imply the existence of the dimer form of DMSO in neat as well as at x = 0.1 of DMSO.In order to simulate and validate our experimental findings, detailed ab initio and density functional theory (DFT) calculations were also performed to obtain the ground state geometries of neat DMSO, self-associated dimer, trimer and their hydrogen bonded complexes with water and methanol. Our calculated structure of DMSO in dimer and trimer form reports a more accurate and stable geometry, in comparison to earlier calculation on these structures. Overall in this study nice spectra-structure correlations were obtained.

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Mineral trioxide aggregate (MTA) has been recommended for pulp capping, pulpotomy, apical barrier formation in teeth with open apexes, repair of root perforation and root canal obturation. Since, its introduction in 1993 by Torabinejad numerous studies have been published regarding various aspects of this material. The aim of this review was to consider MTA as root canal sealer and various laboratory experiments and clinical studies of MTAbased root canal sealers. An extensive search of the endodontic literature was made to identify publications related to MTA-based root canal sealers. The articles were assessed for the outcome of laboratory and clinical studies on their biological properties and physical characteristics. Comparative studies with other sealers were also considered. Several studies were evaluated covering different properties of MTA-based sealers including physical properties, biocompatibility, leakage, adhesion, solubility, antibacterial properties and periapical healing effect. Comparative studies reveal their mild cytotoxicity, but their antibacterial effects are variable. Further research is required to establish the role of MTA as root canal sealers.

A simple, convenient and precise technique for deconvoluting the Lorentzian (true) Raman linewidth, rL , from the observed Raman linewidth, (AV~,~),, [the FWHM (full width at half-maximum) of the Raman line in question], through polyuomial fitting, was developed. The precision of this technique is a consequence of the fact that the values of rL/(bV& (= Y), obtained by exact numerical evaluation of the Voigt profiles for the Raman bands, were fitted to third-and fourth-degree polynomials in S / ( A V~/~)~ (= X), S being the spectral slit width measured as the linewidth (FWHM) of a narrow spectral line recorded at the same slit settings as the Raman line. The procedure of obtaining rL from the knowledge of s, (AvlIZ),, and X, which yields better results, is discussed. Another technique of deconvolution is described and discussed, involving the measurement of Raman linewidths of a particular Raman line for about five or six different slit widths. The measured linewidths (AvlIZ),,, when extrapolated to S + 0, give the value of rL directly. A careful comparison with the other deconvolution techniques reveals that the method of polynomial fitting is relatively more precise than other semi-analytical deconvolution techniques, and the extrapolation technique also gives reasonably good results. The applicability of both methods was tested by taking some selected Raman lines.