Journal of Molecular and Engineering Materials

A two-temperature theory of the generalized thermoelasticity is proposed to study the effect of temperature dependence on a semi-infinite medium. The surface of bounding plane of the medium is under a non-Gaussian laser pulse. Lamé’s coefficients and the thermal conductivity are supposed as temperature-dependent linear functions. The dual-phase-lags (DPLs) theory of the generalized thermoelasticity is applied to treat with the present problem. The analytical solution for different boundary conditions may be deduced by using Laplace transform technique. The numerical results are obtained by using the inverse of Laplace transforms. The comparisons have been graphically presented to show the effects of PLs, temperature discrepancy, laser pulse and laser intensity parameters on field quantities. Also, the results are compared with those obtained from the mechanical and thermal material properties with the temperature independence.

The ability to understand and predict excited state photophysics is vital for the development of photo- and electroluminescence materials, as well as light harvesting materials and photodynamic therapy. Herein, we demonstrate that single determinant time-dependent density functional theory can be computationally cost-effective and has the ability to explain both experimental singlet and triplet dynamics of pyrrolo[3,4-$c$]pyrrole-1,4-dione and pyrrolo[3,2-b]pyrrole-2,5-dione isomers with intriguing photophysical properties. We also used the methodology to predict the photophysical properties of pyrrolo[3,4-c]pyrrole-1,3-dione and a hypothetical hybrid pyrrolo[3,4-b]pyrrole-2,4-dione isomers.

The present study considers the tribological behavior and corrosion resistance of electroless Ni-B-W coatings deposited on AISI 1040 steel substrates. Coating is characterized using scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction technique. In as-deposited condition, coatings are found to be amorphous. On heat treatment, precipitation of crystalline Ni (1 1 1) and its borides take place. For as-deposited coating, the microhardness is obtained as $\sim$759HV${}_{100}$ which increases to $\sim$1181HV${}_{100}$ and $\sim$1098HV${}_{100}$ when heat treated at 350${}^{\circ }$C and 450${}^{\circ }$C, respectively. Incorporation of W in Ni-B coating results in an increase of hardness by 89HV${}_{100}$ in as-deposited condition. Heat treatment also results in increase in crystallite size of Ni (1 1 1). Wear rate and coefficient of friction (COF) of the coatings are evaluated on a pin-on-disc setup under both dry and lubricated sliding conditions. Wear resistance is observed to improve on heat treatment with an increase in crystallite size while COF deteriorates. However, in as-deposited condition, wear rate and COF of Ni-B-W coatings improve by $\sim$5 and $\sim$3 times, respectively, compared with Ni-B coatings. Wear and friction performance of the coatings are enhanced under lubrication due to the columnar structure of the coatings that retain lubricants. Corrosion resistance of Ni-B-W coating in 3.5% NaCl solution gets improved on heat treatment.

An inexpensive, facile, and environmentally benign method has been developed for the preparation of stimuli-responsive and self-healing polyacrylic acid–chitosan-based supramolecular hydrogels. Guanidine hydrochloride is used as the supramolecular crosslinker to form an interconnected network with polyacrylic acid–chitosan complex. Because of the dynamic equilibrium between the hydrogen-bonding sites of the components, the hydrogels were found to be self-healable and sensitive to biochemical-stimulus, such as pH. Controlled loading of drug like doxorubicin and its significant anticancer activity of such hydrogels is worth mentioning.