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Motivated by the potential usefulness of polyethylene glycol (PEG)/Li+ salt mixtures in several industrial applications, we investigated the structure and dynamics of PEG/LiClO4 mixtures in D2O and its mixtures with CD3CN and DMSO‐d6, in a series of PEG‐based polymers with a wide variation in their molecular weights. 1H NMR chemical shifts, T1/T2 relaxation rates, pulsed‐field gradient NMR diffusion experiments, and 2D HOESY NMR studies have been performed to understand the structural and dynamical aspects of these mixtures. Increasing the temperature of the medium results in a significant perturbation in the H‐bonded structure of PEG in its PEG/LiClO4/D2O mixtures as observed from the increase in chemical shifts. On the other hand, the addition of molecular cosolvents has a negligible effect. The hydrodynamic structure of PEG shows a pronounced variation at low temperature with increasing molecular weight, which, however, disappears at higher temperatures. Increasing the temperature leads to a decrease in the hydrodynamic structure of PEG, which can be explained on the basis of solvation–desolvation phenomena. The 2D HOESY NMR spectra reveal a new finding of Li+‐water binding in the PEG/LiClO4/D2O mixtures with the addition of molecular solvents, suggesting that the Li+ cation diffuses freely in the D2O mixtures of polymers as compared with the polymer mixtures with DMSO or CD3CN.

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We present the quantum Otto machine under different optimization criterion when function either as a heat engine or a refrigerator. We examine the optimal performance of the heat engine and refrigerator depending on their efficiency, output power and maximum entropy production. For heat engine case, we obtain the expression for the upper and lower bounds efficiencies at maximum power and maximum ecological function. The optimal ecological performance is laying between the maximum efficiency and the maximum power output. On the other hand, the quantum Otto refrigerator coefficient of performance is optimized for three different criterion – cooling power, χ criterion(product of performance and power) and ecological function. We further study the dimen-sionless power loss to the cold reservoir when the machine is operating as a heat engine as well as its counterpart for the refrigerator case. We find that the maximum operation of the heat engine (refrigerator) cycle is when optimized with respect to hot (cold) reservoir frequency.

Development of low alloy ultra high strength steel with yield strength in excess of 1600 MPa and elongation of 10 % with good fracture toughness is the primary objective of this investigation. The alloys were prepared through electroslag refining (ESR) followed by thermomechanical treatment (TMT). The base alloy was prepared with 0.23 % C, 1.09 % Mn, 5.7 % Cr, 1.18 % Mo, 0.40 % V, 0.19 % Si, 0.011 % S, 0.015 % P, 0.02 % Al and 0.013 % N. Other alloy was developed by inoculation of about 0.06 % titanium in which other elements are kept intentionally similar with the base alloy. The ESR ingots further underwent for TMT to convert it into plates. The specimens of TMT plates of the base alloy displayed tensile strength, yield strength, % elongation and fracture toughness of 1792, 1580 MPa, 7.6 % and 70 MPaHm, respectively while titanium inoculated alloy showed tensile strength of 1885 MPa, yield strength of 1700 MPa, elongation of 8.4 % and fracture toughness of 84 MPaHm. It was observed that the mechanical properties of the titanium inoculated alloy were substantially improved compared to base alloy. Optical, SEM, TEM and EDAX investigations confirmed that the microstructures of the base alloy and titanium inoculated alloy consisted of predominantly bcc lath martensites. TEM and corresponding EDAX studies revealed that the inter lath martensite spacing in the titanium inoculated alloy was finer than the base alloy and also confirmed a homogeneous precipitate of 20-30 nm titanium carbonitrides in titanium inoculated alloy. The improvement of mechanical properties in titanium alloy may be due to refinement of prior austenite grains, inter lath martensite spacing as well as precipitation hardening.