Thermodynamics Modeling for Actinide Monocarbides and Mononitrides from First Principles

The high-temperature thermodynamical properties for the actinide monocarbides and mononitrides ThC, ThN, UC, UN, PuC, and PuN are calculated from first-principles electronic-structure theory. The electronic structure is modeled with density-functional theory (DFT) and is fully relativistic, including the spin-orbit interaction. Furthermore, the DFT is extended to account for orbital–orbital interactions, by means of a parameter-free orbital-polarization (OP) technique, that has proven to be essential for the 5f electrons in plutonium. Strong anharmonicity and the temperature dependence of the lattice vibrations are captured with the self-consistent ab initio lattice dynamics (SCAILD) method. The calculated free energies and heat capacities are compared to published results from quasi-harmonic (QH) theory, and experiments, where available. For the uranium and plutonium compounds, we make use of CALPHAD assessments to help evaluate the theory. Generally, our anharmonic relativistic approach compares well with both CALPHAD and experiments. For the thorium compounds, our theory is in good accord with QH modeling of the free energy at lower temperatures but for the heat capacity the comparison is less favorable.

Evolution of the Efficiency of Divalent Cobalt and Copper Chelates Based on Isatin Derivatives and Thiosemicarbazide Ligands as Inhibitors for the Corrosion of Sabic Iron in Acidic Medium

Divalent cobalt and copper chelates of the two ligands 1-(1- Ethoxycarbonylmethyl-2-oxoindolin-3-ylidene) thiosemicarbazide (EOIT) and 1-(1-Benzyl-2-oxoindolin-3-ylidene) thiosemicarbazide (BOIT) are the target compounds of the current study. Identification of the constitution and geometry of these compounds have been performed using the possible physicochemical and analytical instruments. Elemental analysis, molar conductance and thermal analysis assured the composition of the four chelates to be [Co(POIT)Cl]•1.5H2O, [Cu(POIT)Cl], [Co(BOIT)Cl2(H2O)]•5H2O and [Cu(BOIT)Cl]•Cl which was further confirmed by the measurement of mass spectra. The architecture arrangement of the ligand atoms around Co and Cu centers has been determined depending on the UV-Vis spectral measurements and calculation of µeff values assuring the copper compounds to be square plane whereas the cobalt complexes have tetrahedral or octahedral arrangements. These compounds were examined as corrosion inhibitors for the Sabic steel in 1.0 M HCl utilizing potentiodynamic polarization, electrochemical impedance spectroscopy, mass-loss method and scanning electron microscopy at fixed temperature of 298 K. The acquired outcomes disclosed that the inhibition efficiencies (% IEs) of the examined compounds were set to be dependent on both the concentrations and composition of the compounds. The examined compounds were set to have high % IEs, which were interpreted by strong adsorption of the compounds’ molecules on the iron surface and such adsorption was discovered to follow Langmuir adsorption isotherm. The investigational results obtained from all utilized techniques were set to be in a good accord with each other.

Plantago Major Extract as an Environmentally Friendly Inhibitor for the Corrosion of L-80 Carbon Steel in 0.5 M H2SO4 Media

The inhibition impact of Plantago major leaves extract on carbon steel (CS) which immersed in 0.5 M H2SO4 media was ‎investigated by several methods such as mass loss method (ML), electrochemical impedance spectroscopy (EIS), potentiodynamic ‎polarization (PDP), and electrochemical frequency modulation‎ (EFM). Data obtained from different measurements was showed that %IE enhanced with added the Plantago major extract doses also increased with increasing temperature degree. Thermodynamic adsorption and kinetic parameters of the system were also measured and studied. The ‎adsorption of the Plantago major extract on CS is, according to Temkin isotherm. The ‎ curves from PDP explained that the Plantago major extract is considered as a mixed-type inhibitor. The EIS technique's acquired data verified that the studied extract produced a thin layer that covers and protects the CS surface. Atomic ‎Force Microscopy (AFM) and Fourier Transform Infrared (FT-IR) analysis conformed that Plantago major extract was adsorbed on CS surface. The data obtained from unlike measurements were in good accord.

Analytical Model and Computing Optimization of a Compliant Gripper for the Assembly System of Mini Direct-Current Motor

This study proposes a combination of kinematics-based design method, statistic method, and TLBO algorithm to solve computing optimization for a compliant gripper. It is employed in an assembly system of mini direct current motor. First, the kinematic models of the gripper are developed. The static model is paid attention. Next, the dynamic model is established based on Lagrange's principle. Then, a multi-criteria optimization for the gripper is conducted by Taguchi method integrated with TLBO algorithm. Finally, the FEA and experiments are implemented to verify the optimal results and evaluate the performances of the compliant gripper. The results indicated that theoretical models are in good accord with the results from simulations and experiments. Additionally, the performance of the present method is superior to PSO algorithm. The results revealed that the compliant gripper allows a displacement up to 3000 µm and the amplification ratio of 12 times. The compliant gripper is a potential application for the mini direct-current motor assembly system.

Ashwagandha Extract as Green Sustainable Corrosion Inhibitor for Aluminum in Acidic Solutions

In this study, the employment of Ashwagandha extract (AE) as a green sustainable corrosion inhibitor for aluminum in one molar hydrochloric acid solutions was examined utilizing “mass loss (ML), electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) measurements”. The surface examination was analyzed utilizing atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) analysis. The effect of temperature on corrosion demeanor with adding a different dose of AE was investigated within the temperature varieties of 25-45 ºC by ML strategy. The curves of polarization reveal that AE is considered as a mixed sort inhibitor. The performance of inhibition rises with raising the AE concentration and diminished with the temperature ascending. The adsorption of the inhibitor on aluminum surface complies with the Langmuir’s adsorption isotherm and is considered as physisorption. The outcomes attained from chemical and electrochemical methods are in good accord.

Thermal conductivity and conditioning of grey expanded polystyrene foams

This article focuses on the thermal conductivity of 50 mm thick silver grey (infrared absorbing) expanded polystyrene (EPS) foam boards blown with pentane. The effect of short-term ageing from the point of production, by ambient conditioning at 23°C/50% RH, is compared to conditioning at an elevated temperature of 70°C. The declared thermal properties of the product and CE certification are fulfilled by the requirements of the European EPS product standard and SG19 Guidance. Measured thermal conductivity levels within 1% of the final value are acceptable and considered representative throughout the economic life of the product. Levels within the criteria were determined for 50 mm silver EPS after conditioning for 5 days at an elevated temperature of 70°C, whereas for conditioning at 23°C/50% RH the time taken was 23 days. The latter time is in good accord with retesting retained grey EPS boards of similar density and up to 9 years old, after initial testing 22 days from production, and conditioning at 23°C/50% RH. Elevated temperature conditioning increases the rate of diffusion of the blowing agent, but there has been concern about EPS beads softening above 60°C. Although there is little evidence from scanning electron microscopy of significant increase in perforation of the cell membranes at elevated temperatures, there is some indication of a small increase in wrinkling of the walls and intercell skeletal strands at 60°C and 70°C. It takes longer to eliminate the pentane gas by conditioning at 23°C/50% RH but there is no risk of material change from heat conditioning.

Energy Gap-Refractive Index Relations in Perovskites

In this study, the energy gap-refractive index relations of perovskites are examined in detail. In general, the properties of perovskites are dependent on the structural reorganization and covalent nature of their octahedral cages. Based on this notion, a simple relation governing the energy gap and the refractive index is proposed for perovskites. The results obtained with this relation are in good accord with the literature values and are consistent with some well-established relations.

Crystallographic and Computational Analysis of 4H-Pyran-3-Carboxylate Derivative Tethered with Amino and Methacryloyloxyethy l Units

A single crystal of pyran derivative 1 was grown and analysed. The molecular structure of the same was theoretically executed through DFT approach. The frequencies and geometrical parameters obtained from computations are in good accord with the ones obtained through experimental. The calculated energies of HOMO and LUMO imply that transfer of charge happens within the molecule. Besides, the MEP analysis of the molecule 1 was examined using DFT calculations. X-Ray structural analysis (single crystal) of the molecule 1 implies that the pyran structural unit of the molecule adopts “flattened-boat” conformation.

Experimental Analysis of Performance and Thermal Capability of Three Phase Squirrel Cage Induction Motor Using Plastered Composite Conductors

Background: This article deals with the analysis on improved performance and efficiency of induction motor by using nano composites for stator winding. Methods: The nanocomposites are added with different enamel. Enamel is mostly preferred for induction motors’ winding, due to three main reasons: adhesion, infusion and plaster. To predetermine the plaster and nanocomposite conductor’s behavior when they are used for transmitting AC currents and developing AC magnetic field, a numerical analysis is performed. The total heat losses are determined by the heat run test. Open circuit and short circuit tests are used to analyze the performance and efficiency of the proposed induction motor. Results: The AC losses of composite and plaster conductors having good accord are compared with previous solid and hollow conductors. Analysis of the coil by a composite and plaster conductor shows that the AC losses in low current are lower than the coil, which is wrapped by a solid, and hallow conductors. Due to this reason, composite and plaster conductors are considered advantageous for low and medium power motors. Conclusion: Adding nano composites with the plaster material will help to improve electrical, thermal and mechanical characteristics. The property of enamel can change the lifetime of induction motor. The induction motor winding makes use of nano composites SiO2 and TiO2 with enamel coated.

High spin states of Zr isotopes around A = 80 mass region — A study on cold and hot rotating nuclei

High spin structure of Zr isotopes, in particular, around [Formula: see text] has been studied in yrast and nonyrast regions. Spin dependence of shapes for the yrast levels are investigated by employing Cranked Hartree–Fock–Bogoliubov (CHFB) theory using a [Formula: see text] model interaction and the calculations are in good accord with the experimental data. The nonyrast states are treated by incorporating temperature degree of freedom using the statistical theory (ST). Highly deformed prolate shapes dominate the nonrotating proton rich region at low temperatures (T) with coexisting oblate and prolate shapes in [Formula: see text]Zr. Hot rotating nuclei show highest deformation around [Formula: see text] among all the other Zr isotopes even at high temperatures. [Formula: see text]Zr exhibits interesting structural transitions, hence studied in detail in yrast and non yrast regions. Triaxiality predominates in both yrast and nearly yrast (low temperature) regions at low spins with transition to elongated shapes at mid spin values 30–38[Formula: see text] to highly deformed oblate shapes at higher spins. CHFB predicts a strong backbending effect at 32[Formula: see text] and 40[Formula: see text]. A shape coexistence between the rare shape phase of noncollective prolate and oblate is reported in [Formula: see text]Zr at low temperature and [Formula: see text]. Prolate shape phase disappears with increasing temperature and spin but the nucleus remains highly deformed (with [Formula: see text] at spin [Formula: see text]40[Formula: see text]) even at high temperatures of the order of 3–3.5[Formula: see text]MeV, hence a very promising candidate for GDR probes of nuclear shapes.