Elongation improvement in nano bainite steel obtained from plastically deformed primary austenite

ABSTRACT

Ausforming is being widely used to overcome the kinetics barrier in nanostructured bainitic steels and to enhance its practical industrial applications. It would also affect the microstructural characteristics and consequently the resultant mechanical performance. This article aims to investigate the tensile behaviour of nano bainite obtained from plastically deformed primary austenite at three different heat treatment stages. 10% of ausforming has been implemented and nanostructured bainite obtained after austempering at 300°C for 2, 4 and 6?h in salt bath furnaces. Results indicated that ausforming could successfully increase the volume fraction of bainite within the microstructure and refine the bainite packets sizes. Moreover, it has been demonstrated that higher mechanical stability of retained austenite and therefore more effective TRIP effect could be attained during the tensile test which consequently resulted in elongation improvement without deteriorating the strength properties. This claimed to be beneficial for materials performance during practical applications.     

Development of soot formation sub-model for Scania DC-9 diesel engine in the steady-state condition

Journal of Thermal Analysis and Calorimetry - The purpose of the present study is to provide a sub-model for the formation and oxidation of soot based on chemical kinetics for the DC-9 Scania...     

Synthesis of new dyes containing double tetrazole groups for sensitization of TiO<Subscript>2</Subscript> nanoparticles in dye-sensitized solar cells

Di(1H-tetrazol-5-yl)methane is employed as a new electron acceptor group in the synthesis of two metal-free organic dyes containing triphenylamine donor group. Dye-sensitized nanocrystalline TiO₂ solar cell (DSSC) applying these novel dyes is constructed for consideration of their photovoltaic properties. The electronic properties of the dyes are also considered with the aid of theoretical calculations. The DSSC constructed from 4-(2,2-di(1H-tetrazol-5-yl)vinyl)-N,N-diphenylaniline (T1) shows a short-circuit photocurrent density of 13.38 mA cm^?2, an open circuit voltage of 578 mV, and a fill factor of 0.54, with a resulted solar energy-to-electricity conversion efficiency of 4.18% under simulated 1 sun irradiation (100 mW cm^?2). This result reveals that the dye with the di(1H-tetrazol-5-yl)methane anchoring group injects more electrons to the conduction band of TiO₂ in comparison with its analogs with single tetrazole ring in their anchoring group. It is found that in spite of a red-shift of the absorption spectrum resulted from the lengthening of the molecule, the dye with two di(1H-tetrazol-5-yl)methane groups gives lower performance than the dye with a single electron acceptor.     

Magnetically nano core–shell Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@Cu(OH)<Subscript>x</Subscript>: a highly efficient and reusable catalyst for rapid and green reduction of nitro compounds

Magnetically separable nano core–shell Fe₃O₄@Cu(OH)_x with 22 % Cu content was prepared by the addition of sodium hydroxide to a mixture of CuCl₂·2H₂O and nano Fe₃O₄ in water. Characterization of the impregnated copper hydroxide was carried out by X-ray fluorescence (XRF), X-ray diffraction (XRD) atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), value stream mapping (VSM) and Brunauer–Emmett–Teller (BET) analysis. The core–shell nanocatalyst exhibited the excellent catalytic activity toward reduction of various nitro compounds to the corresponding amines with NaBH₄. All reactions were carried out in H₂O (55–60 °C) within 3–15 min to afford amines in high to excellent yields. Reusability of core–shell Cu(OH)_x catalyst was examined 9 times without significant loss of its catalytic activity.     

Preparation of conductive,flexible and transparent films by in situ deposition of polypyrrole nanoparticles on polyethylene terephthalate

In this study polypyrrole (PPy) nanoparticles were deposited as a thin film on the modified surface of polyethyleneterephthalate (PET) by in situ chemical polymerization in the presence of sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (DBSNa) and mixture of them as the surfactant. The surface of PET was modified by KOH before deposition and was investigated for conductivity and adhesion of PPy nanoparticles to PET. Resulting conductive flexible films were characterized by UV–Vis spectroscopy, fieldemission scanning electron microscopy, contact angle measurements and four-point-probe technique for conductivity. Direct morphological observation (FESEM) and electrical measurements indicated that the morphology, conductivity and the nature of deposited PPy films depend on surfactant, surface modification of PET and monomer concentration. In optimized process condition, uniform conductive films of PPy were obtained with good adhesion to PET.     

Asymptotic Behavior of Quasi-Autonomous Expansive Type Evolution Systems in a Hilbert Space

We introduce the notion of almost expansive sequences and curves and study their ergodic and asymptotic properties in a Hilbert space H. We apply our results to study the asymptotic behavior of solutions to the quasi-autonomous expansive type evolution system (du/dt)(t) + f(t) ∈ Au(t) on [0, ∞).     

Cascade synthesis of fused polycyclic dihydropyridines by Ni–Zn–Fe hydrotalcite (HT) immobilized on silica-coated magnetite as magnetically reusable nanocatalyst

Research on Chemical Intermediates - An efficient ecofriendly approach has been developed for one-pot multicomponent synthesis of fused polycyclic dihydropyridine (DHP) derivatives. Tandem...