Possibility to Use Hydrothermally Synthesized CuFeS<Subscript>2</Subscript> Nanocomposite as an Acceptor in Hybrid Solar Cell

Here we have approached the plausible use of CuFeS₂ nanocomposite as an acceptor in organic–inorganic hybrid solar cell. To produce CuFeS₂ nanocomposite, hydrothermal strategy was employed. The room-temperature XRD pattern approves the synthesized material as CuFeS₂ with no phase impurity (JCPDS Card no: 37-0471). The elemental composition of the material was analyzed from the TEM-EDX data. The obtained selected area electron diffraction (SAED) planes harmonized with the XRD pattern of the synthesized product. Optical band gap (4.14 eV) of the composite from UV–Vis analysis depicts that the synthesized material is belonging to wide band gap semiconductor family. The HOMO (? 6.97 eV) and LUMO (? 2.93 eV) positions from electrochemical study reveal that there is a possibility of electron transfer from MEH-PPV to CuFeS₂. The optical absorption and photoluminescence spectra of MEH-PPV:CuFeS₂ (donor:acceptor) composite were recorded sequentially by varying weight ratios. The monotonic blue shifting of the absorption peak position indicated the interaction between donor and acceptor materials. The possibility of electron transfer from donor (MEH-PPV) to acceptor (CuFeS₂) was approved with photoluminescence analysis. Subsequently, we have fabricated a hybrid solar cell by incorporating CuFeS₂ nanocomposite with MEH-PPV in open atmosphere and obtained 0.3% power conversion efficiency.     

Sustainable synthesis of cyclic carbonates from bio‐based polyether polyol: the structure characterization,rheological behaviour and thermal properties

The cycloaddition of CO₂ to epoxides represents a green efficient method to form bis(cyclic carbonate)s. The main purpose of the work reported in this paper was to examine the effect of the gas flow rate (20, 40, 60 and 100 mL min^–1) during carbonation on the conversion yield, chemical structure, rheological behaviour and thermal properties of the prepared compounds. A series of new bis(cyclic carbonate)s was obtained from bio‐based polyether polyol. The syntheses were performed in the absence of toxic solvents and the process did not require the use of elevated pressure. The progressive structural changes and the presence of characteristic chemical groups were monitored by attenuated total reflection Fourier transform infrared spectroscopy. The characterization of the structure by ¹H NMR and ¹³C NMR also confirmed the formation of cyclic carbonate moieties. The non‐Newtonian behaviour and the optimal mathematical model (Herschel–Bulkley) were verified by rheological measurements. The materials obtained could be used as a chemical intermediate to synthesize advanced materials based upon polyurethanes without using isocyanates. © 2019 Society of Chemical Industry     

Real-Time Ultrasonic Monitoring of the Vulcanization Process in Nitrile Rubbers

Russian Journal of Nondestructive Testing - Nitrile rubbers, also known as Nitrile-Butadiene rubbers, belong to the category of synthetic rubbers and are a better choice as materials for...     

Buckling and dynamic instability analysis of stiffened shell panels

The static and dynamic instability characteristics of stiffened shell panels subjected to uniform in-plane harmonic edge loading are investigated in this paper. The eight-noded isoparametric degenerated shell element and a compatible three-noded curved beam element are used to model the shell panels and the stiffeners, respectively. As the usual formulation of degenerated beam element is found to overestimate the torsional rigidity, an attempt has been made to reformulate it in an efficient manner. Moreover, the new formulation for the beam element requires five degrees of freedom per node as that of shell element. The method of Hill's infinite determinant is applied to analyze the dynamic instability regions. Numerical results are presented through convergence and comparison with the published results from the literature. The effect of various parameters like shell geometry, stiffening scheme, static and dynamic load factors, stiffener size and position, and boundary conditions are considered in buckling and dynamic instability analysis of stiffened panels subjected to uniform in-plane harmonic loads along the boundaries.     

Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash

Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U_max) and saturation value constant (K_B) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor.     

Linear circuits: a measurement‐based approach

This paper proposes a new measurement‐based approach that can solve synthesis problems in unknown linear circuits. The method makes use of a small number of measurements to determine the functional dependency of any circuit signal or variable on any set of design variables. Once the functional dependency is obtained, the design requirements can be applied to find the design parameter values. The results are described for linear direct current and alternating current circuits. Copyright © 2013 John Wiley & Sons, Ltd.     

Poly(ethylene oxide)‐g‐gellan polysaccharide nanocarriers for controlled gastrointestinal delivery of simvastatin

Herein, a novel gellan polysaccharide‐based amphiphilic copolymer was synthesized for the development of simvastatin‐loaded micellar nanoparticles. The nanoparticles were explored for their controlled drug release and improved pharmacodynamic potentials. The copolymer was characterized by Fourier transform infrared spectroscopy (FTIR) and elemental analysis. The onset of copolymer micellization was detected by fluorescence spectroscopy. Simvastatin was loaded into micellar particles by solvent evaporation method and the particles were then characterized by microscopic and light scattering techniques. The physical state of drug was studied by X‐ray diffraction analysis. Pharmacodynamic assessment of the micellar preparations was done on rabbit models. The copolymer formed micellar nanoparticles in water. Critical micellar concentration was 9.12mg/l. The micellar particles (426.8–912.6nm) entrapped a maximum of 18.86% drug. Higher negative zeta potential indicated physical stability of micellar systems. A simple diffusion mechanism was operative in the event of comparatively faster drug release in pH6.8 phosphate buffer solution. No significant drug‐copolymer interaction was traced by FTIR spectroscopy. The amorphization of drug into micellar particles reduced LDL‐cholesterol level by ～45% in hyperlipidemic rabbits and this was about 2.5 times higher than pure drug dispersion. Copolymer micellar nanoparticles of simvastatin could control cholesterol level in hyperlipidemic rabbits and thus had potential in drug delivery applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42399.     

Determination of compounding formulation of cured rubber by reverse engineering

The present work deals with reverse engineering on four rubber formulations. Information about the material composition of the compounding formulations was obtained by using techniques such as acetone extract, thermogravimetric analysis, energy dispersive X‐ray fluorescence studies, and Fourier transform infrared (FTIR) spectroscopy in attenuated total reflection mode. The reverse engineered formulations were compared on a qualitative and quantitative basis with the initial formulations. The aim was to ascertain the validity of the methodology, which may be used as reverse engineering of rubber compounds to quantitatively analyze unknown ground tire rubber in future. The state of the art was based on a fractional mass transfer from acetone extract to the rubbers detected in TGA. Through this new approach, the formulations calculated were very consistent with the formulations employed, thus establishing the validity of the methodology used. POLYM. ENG. SCI., 55:1450–1458, 2015. © 2015 Society of Plastics Engineers