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Abstract.In this research article, we present novel imputation methods designed to address missing data challenges in sample surveys. We then introduce innovative estimation procedures for calculating population means based on these methods. Our study thoroughly examines the properties of these new estimation procedures, assessing their biases and mean square errors. Through the use of both real and simulated data sets, we demonstrate the superior performance of our proposed estimators compared to existing methods in similar scenarios. In conclusion, we offer practical recommendations for survey practitioners. [ABSTRACT FROM AUTHOR]

In the present study, we consider a generalized Weyl conformal curvature tensor on para-Kenmotsu manifolds (briefly, PK-manifolds). First we describe certain vanishing properties of generalized Weyl conformal curvature tensor (brifly, GWC-curvature tensor) on a PK-manifold. Later, we study generalized Weyl conformally semi-symmetric PK-manifold that turns out to an Einstein manifold. Among others, it has been shown that the generalized Weyl conformally Φ-symmetric PK-manifold is of constant curvature or dr(Ψ) = 0. [ABSTRACT FROM AUTHOR]

A liquid crystals nanoparticles composite was prepared by dispersing barium titanate nanoparticles (BT-NPs) into a multi-component liquid crystalline material having wide range room temperature nematic phase. The thermodynamic, optical textures, electro-optical and dielectric properties of the composite sample were studied along with pristine materials. Isotropic to nematic phase transition temperature was enhanced for nano-composites as observed from thermodynamic, optical textures and dielectric investigations. Effect of BT-NPs dispersion on various display parameters of nematic liquid crystals, namely, threshold voltage, dielectric anisotropy, DC conductivity and splay elastic constant has been explored. A relaxation mode in kHz frequency range has been observed for pure and nano-composites samples, which varies with temperature and follows Arrhenius behaviour. DC conductivity enhances approximately fivefold for BT-NPs dispersed samples. The host liquid crystalline material has nematic ordering which supports alignment of BT-NPs parallel to the nematic director which consequently improves thermal stability, dielectric and electro-optical parameters of the nano-composite system. [ABSTRACT FROM AUTHOR]

Pure polypyrrole (ppy) doped with different weight percent of papain was synthesized by in situ polymerization. These different compositions of pyrrole and papain composite polymers were analyzed for direct current (DC) conductivity. The size of the particle calculated by using the Scherrer equation and Williamson-Hall (W-H) plot was found to be in the range of 15 nm -- 20 nm. Activation energies evaluated by using Arrhenius plots show an increase in activation energy from base ppy to papain-ppy composite polymer. The activation energy was found to vary from 22.4 meV to 34.4 meV for papain-ppy composite. The experiment revealed that Mott's Variable Range Hopping model (VRH) for three dimensions (3D) applies to pure polypyrrole and papain-ppy composite. The density of states at the Fermi level N(EF) were found to be 2.7 x 1021 eV-1cm-1 for pure ppy and ranged from 0.3 x 1019 eV-1cm-1 to 0.8 x 1020 eV-1cm-1 for the composite polymer. The average hopping range and average hopping energy of pure ppy and composite polymers were also calculated. [ABSTRACT FROM AUTHOR]

Electronic bandgap calculations are presented for 2400 experimentally known materials from the Materials Project database and the bandgaps, obtained with different types of functionals within density functional theory and (partial) self-consistent GW approximation, are compared for 20 randomly chosen compounds forming an unconventional set of ternary and quaternary materials. It is shown that the computationally cheap GLLB-SC potential gives results in good agreement (around 15%) with the more advanced and demanding eigenvalue-self-consistent GW. This allows for a high-throughput screening of materials for different applications where the bandgaps are used as descriptors for the efficiency of a photoelectrochemical device. Here, new light harvesting materials are proposed to be used in a one-photon photoelectrochemical device for water splitting by combining the estimation of the bandgaps with the stability analysis using Pourbaix diagrams and with the evaluation of the position of the band edges. Using this methodology, 25 candidate materials are obtained and 5 of them appear to have a realistic possibility of being used as photocatalyst in a one-photon water splitting device.

Laser marking is the process to mark an image by utilizing laser thermal energy used primarily for product identifications and traceability. It is versatile and well known process employed by the manufacturers to mark various materials. The mark produced by a fibre laser beam produces one of the fine marking components and it is well accepted form of marking used nowadays. The research paper revealed that laser beam marking quality is the function of various input controlling factors like laser spot size, transverse feed, scan rate, laser power which had a significant impact on quality attributes. The paper focuses on the creation of better quality equilateral triangular-shaped laser inscribed image on grade 304 stainless steel surface in a shortest possible time. The process variables involved in the present study includes pulse rate, duty cycle, laser power, and scan rate which were varied one at a time for obtaining better marking quality characteristics like high mark quality, closer to target mark angle and less deviation of marked area. The observed results revealed that pulse rate of 50 kHz, laser power of 12.5 W, scan rate of 35 mm/s and duty cycle of 99% provides better marking quality. [ABSTRACT FROM AUTHOR]

The purpose of the present paper is to study some properties of para-Sasakian manifold admitting Zamkovoy connection. We obtain some interesting result on para-Sasakian manifold. It is shown that M-projectively flat para-Sasakian manifold is η-Einstein manifold. [ABSTRACT FROM AUTHOR]

In the present paper, the influence of machining parameters and thermal treatment cycles on the fatigue life of SAE8620 has been investigated. Experiments were designed as per L9 array and a set of nine fatigue test samples were prepared using CNC machine. Spindle speed (1900, 2100, and 2300 rpm), feed rate (0.15, 0.175, and 0.2 mm/min), and depth of cut (0.2, 0.4, and 0.6 mm) were the three machining parameters that were included for the analysis. The three different cooling rates were annealing (0.8℃/min), normalising (13℃/min), and water quenching (421℃/min). Surface roughness testing were carried out first, followed by fatigue tests. The Taguchi method was used to optimise the machining settings (spindle speed − 2100 rpm, feed rate − 0.175 mm/min and depth of cut − 0.4 mm). To determine the missing output values, the ANFIS modelling tool was employed and the predicted value was 1.07 µm. The optimal surface roughness (1.261 µm) and fatigue cycle (41149 cycles) were obtained by grey relation analysis for input parameters (spindle speed − 2300 rpm, feed rate − 0.175 mm/min and depth of cut − 0.4 mm). The so obtained optimised surface roughness values found to be close by 15.14%. It was found that fatigue life get enhanced due to synergistic effect of heat treatment (average 56%) and surface roughness (25%), respectively. Therefore, inference can be made that the fatigue life can be significantly influenced by the heat treatment and surface roughness. [ABSTRACT FROM AUTHOR]