3,046 research outputs found
Ab-initio insights into the structural, elastic, bonding, and thermophysical properties of UHx (x = 1, 2, 3, 5, 6, 7, 8) under pressure: possible relevance to high-Tc superconductivity
Binary uranium hydrides, UHx (x = 1, 2, 3, 5, 6, 7, 8), with different
crystal symmetries are potentially interesting compounds for high-Tc
superconductivity and as hydrogen storage systems. In this work we have
explored the structural, elastic, mechanical, bonding, and thermophysical
properties of these systems under uniform pressure via density functional
theory based computations. Most of the results disclosed in this work are
novel. From the calculations of the cohesive energy and enthalpy of formation,
we have found that the titled compounds are chemically stable. The computed
elastic constants at different pressures ensure elastic stability. All the
binary hydrides are mechanically anisotropic. Pressure induced brittle-ductile
transition takes place under high pressure. The compounds are machinable with
the cubic {\alpha}-UH3-Pm-3n showing very high value of the machinability
index. All the compounds are fairly hard with cubic UH8 showing superhard
character. The Debye temperatures and acoustic velocities of these compounds
are high; the highest value is found for the cubic UH8. The melting
temperature, Gr\"uneisen parameter, minimal phonon thermal conductivity, and
the thermal expansion coefficient of these compounds have also been studied at
different pressures. All these parameters show excellent correspondence with
the estimated Debye temperature, elastic parameters and bonding
characteristics
SynthEnsemble: A Fusion of CNN, Vision Transformer, and Hybrid Models for Multi-Label Chest X-Ray Classification
Chest X-rays are widely used to diagnose thoracic diseases, but the lack of
detailed information about these abnormalities makes it challenging to develop
accurate automated diagnosis systems, which is crucial for early detection and
effective treatment. To address this challenge, we employed deep learning
techniques to identify patterns in chest X-rays that correspond to different
diseases. We conducted experiments on the "ChestX-ray14" dataset using various
pre-trained CNNs, transformers, hybrid(CNN+Transformer) models and classical
models. The best individual model was the CoAtNet, which achieved an area under
the receiver operating characteristic curve (AUROC) of 84.2%. By combining the
predictions of all trained models using a weighted average ensemble where the
weight of each model was determined using differential evolution, we further
improved the AUROC to 85.4%, outperforming other state-of-the-art methods in
this field. Our findings demonstrate the potential of deep learning techniques,
particularly ensemble deep learning, for improving the accuracy of automatic
diagnosis of thoracic diseases from chest X-rays.Comment: Accepted in International Conference on Computer and Information
Technology (ICCIT) 202
First-principles pressure dependent investigation of the physical properties of KB2H8: a prospective high-TC superconductor
Using the density functional theory (DFT) based first-principles
investigation, the structural, mechanical, hardness, elastic anisotropy,
optoelectronic, and thermal properties of cubic KB2H8 have been studied within
the uniform pressure range of 0 - 24 GPa. The calculated structural parameters
are in good agreement with the previous theoretical work. The compound KB2H8 is
found to be structurally and thermodynamically stable in the pressure range
from 8 GPa to 24 GPa. Single crystal elastic constants Cij and bulk elastic
moduli (B, G and Y) increase systematically with pressure from 8 GPa to 24 GPa.
In the stable phase, KB2H8 is moderately elastically anisotropic and ductile in
nature. The compound is highly machinable and fracture resistant. The Debye
temperature, melting temperature and thermal conductivity increases with
pressure. The results of electronic band structure calculations and optical
parameters at different pressures are consistent with each other. The compound
is optically isotropic. The compound KB2H8 has potential to be used as a very
efficient solar energy reflector. The electronic energy density of states at
the Fermi level decreases systematically with increasing pressure. The same
trend is found for the repulsive Coulomb pseudopotential. Possible relevance of
the studied properties to superconductivity has also been discussed in this
paper
The factors of selecting Malaysia as tourist destination
Tourism is an emerging economic sector for Malaysia.The purpose of this study is an attempt to understand the factors that attract tourists to visit Melaka State of Malaysia.The primary data were collected through questionnaire survey on 735 tourists who visited the state of Melaka, Malaysia.This study used descriptive statistics, confirmatory factor analysis, and structural equation modelling (SEM) in order to analyze and draw the inferences.Model fit was initially tested using the overall fit and regression paths. Then the hypothesized model was analysed and modified based on the results of the analysis to find a better fit of the data and to more adequately describe the relationships between the factors. The study found that several economic, environmental, cultural and community factors have positive significant influence in attracting tourists to Melaka
STUDY OF HOMOGENEITY, POROSITY AND INTERNAL DEFECTS IN AERATED AND EPS AGGREGATE POLY BRICKS USING NEUTRON RADIOGRAPHY TECHNIQUE
A powerful non-destructive testing (NDT) technique is adopted to study the internal defects and elemental distribution/homogeneity and porosity of aerated brick and EPS aggregate poly brick samples. In the present study the internal defects like homogeneity, porosity, elemental distribution, EPS aggregate and aerator distributor in the test samples have been observed by the measurement of gray value/optical density of the neutron radiographic images of these samples. From this measurement it is found that the neutron intensity/optical density variation with the pixel distance of the AOI of the NR images in both expanded polystyrene (EPS) aggregate poly brick and aerated brick samples comply almost same in nature with respect to the whole AOI but individually each AOI shows different nature from one AOI to another and it confirms that the elemental distribution within a AOI is almost homogeneous. Finally it was concluded that homogeneity, elemental distribution in the EPS aggregate poly brick sample is better than that of the aerated brick sample
- …