National Academy Science Letters最新文献

This study aims to develop hybrid polymer laminate (HPL) structure utilizing the 3D printing fused filament fabrication (FFF) method and analyze the printing process. The HPL plates were fabricated using PETG and nylon 66 thermoplastic polymers at varying infill densities, printing speeds, and layer thicknesses. The experimental setup followed a fixed matrix based on the L9 orthogonal array (OA). Each HPL consisted of a bottom layer printed with nylon 66, with PETG layers sandwiched on top. Subsequently, the samples underwent testing using a UTM m/c to assess their tensile and flexural strength, as well as printing efficiency. Warping was observed on the printed samples, with a maximum tensile strength of 27 MPa and flexural strength of 14.5 MPa recorded. Notably, different strength values were observed when altering printing parameters. While the printing process was successful, the resulting HPL exhibited slightly lower strength compared to PETG or nylon 66 filaments. The study achieved a maximum printing efficiency of 90% (η), with the layer thickness parameter significantly impacting tensile properties. These findings offer valuable insights and required for various industrial applications, including wind turbines, electronics, automotive, and aeronautics.

The present study is an theoretical attempt to predict the variation of melting temperature of some nanoparticles with shape and size from simple theoretical model. The theoretical model is based on cohesive energy of nanoparticles in compression with the bulk materials. Here we have considered Sn, Au, Ag, Al, Ni and Pb nanoparticles for the study of shape and size dependence behaviour of melting temperature. The overall study found that the melting temperature of nanomaterials is depend on shape and size and the value of melting temperature increases with increase in size of nano solids. Further, It has been observed that nano film shape have highest melting point and regular tetrahedron shape has lowest melting point among all the considered shape.

In this paper, we construct a new wavelet transform in the framework of the quadratic-phase Hankel transform. Further, we establish the Parseval’s relation and reconstruction formula of continuous quadratic-phase Hankel wavelet transform.

Mustard aphid, Lipaphis erysimi pseudobrassicae is an insect pest that feeds on phloem sap, causing significant damage to crops through direct feeding and virus transmission. This pest species harbors both primary and secondary endosymbionts that play crucial roles in their survival and interaction with the host plant. Among these endosymbionts, Buchnera aphidicola is the primary symbiont that compensates for nutrient deficiencies in the phloem sap diet, while several secondary endosymbionts, like Wolbachia sp, Arsenophonus sp, Rickettsia sp, Hamiltonella sp, Serratia sp and Cardinium sp serve various functional roles in the aphids. To understand the association between these primary and secondary endosymbionts in L. e. pseudobrassicae, we conducted species confirmation studies in 16 populations collected from 13 different states and 1 Union territory in India and used species-specific primers targeting 16S rRNA gene to detect the presence of these endosymbionts. The PCR amplification confirmed the occurrence of Buchnera sp in all individual aphids with 100% occurrence, followed by Wolbachia sp, Rickettsia sp, and Hamiltonella sp with 81.25% incidence and Cardinium sp least (31.25%). Overall, the current study revealed the presence of bacterial endosymbionts in L. e. pseudobrassicae populations from India, indicating the need for further research to better understand the implications of these endosymbionts on the biology of aphids and their potential impacts on crop health and management.

Glabrin, a bioactive compound first discovered in Pongamia pinnata seeds has sparked interest for its putative antibacterial potential. In this study, we present a simple and rapid method for the isolation of Glabrin followed by its structural characterization using Density Functional Theory (DFT) and single X-ray crystallography (XRD). Furthermore, in silico and in vitro assessments were conducted to evaluate the antimicrobial nature of Glabrin. Additionally, the mode of antibacterial action was elucidated using Field Emission Scanning Electron Microscopy (FESEM), cell leakage assays, and flow cytometry. Our findings provide insights into the antimicrobial potential of Glabrin and its mechanism of action against bacterial pathogens.

Researches in geotechnical engineering and day-to-day up-gradation in the earth moving machineries have enabled the construction of high earthen dams more easy and safe. With changing seismic conditions of the tectonic plates, it has become important to design each structure in a way it can withstand various earthquake conditions. Although, flexibility of soil material offers good seismic stability to the structures but stability of earthen structures depends largely on geometry, material properties and different conditions it has to bear during its design life. An earthen dam designed keeping all these aspects in mind, is a cost-efficient method of retaining water. This work is centered around the analysis of slope stability of a section of Durgawati Earthen Dam built in Kaimur district of Bihar. The study takes into concern the behavior of slope of the earthen dam under different drawdown conditions along with seismic conditions developed. Various methods have been developed for slope stability analysis but all have some or the other limitations. Thus, the exact behavior of the dam in real-time is not predictable. Here, a comparative analysis of conventional method and finite element method has been run. In the study, it has been found that the difference in conventional and finite element method can reach upto 40%. The change of factor of safety (FOS) in different situations gives us an overview of the crucial phase in dam’s design life.