Cellulose acetate (CA) nanofiber membrane was prepared by electrospinning method using solvent mixtures of methyl ethyl ketone (MEK) and N, N, - dimethylacetamide (DMAc) in different ratios (2:1, ...1:1, 1:2) and also different concentration of CA (7–19%). MEK was selected in place of acetone due to its high boiling point, thereby, minimises the evaporation loss of the solvent enabling the longer duration of electrospinning. The morphology of electrospun nanofibers was observed by Scanning Electron Microscope (SEM). It was observed that cylindrical fibers formed at higher concentration of polymer with increase of DMAc. Fiber diameters were in the range of 40–500 nm with large diameters formed at higher polymer concentration. Contact angle measurement revealed that membranes have good wetting property. The water flux measurements of membranes were carried out under gravity. A water flux of 10,197 Lm−2h−1 was measured initially and was reduced subsequently to 365-200 Lm−2h−1. The membranes could be reused up to four times without rupture. The above experiments suggest that MEK and DMAc could be an alternate solvent system in addition to other systems.
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•Cellulose acetate nanofibers electrospun using high boiling point solvent mixture of MEK and DMAc.•Formation of cylindrical and beaded CA nanofibers mapped vs. solvent ratios and polymer concentration.•Sessile drop experiments proved hydrophilic nature & good wettability.•Membranes had DI water flux of 10,197.044 Lm−2h−1 for initial 50 ml.•Membranes could be reused four times without rupture and suitable for water filtration application.
Bismuth layer-structured ferroelectric (BLSF) ceramics exhibit linearity in resistivity with respect to temperature changes, and therefore find application as high-temperature sensor materials. In ...this study, calcium bismuth titanate (CBT), a BLSF material, was synthesized by calcining combined oxide precursors at 850°C for 2 h, and its particle size distribution, phase analysis, grain size distribution and morphology were characterized. Circular discs were prepared by sintering in the temperature range of 1000 to 1200°C. The sintered discs were characterized for dielectric constant (
K
), P-E hysteresis loop and DC electrical resistivity (
ρ
) from 100 to 900°C. The highest density (> 95% Th.) was obtained for samples sintered at 1175°C. DC resistivity decreased linearly from 10
14
to 10
5
Ω cm with the rise in temperature from 100 to 900°C, therefore confirming CBT as a prospective high-temperature sensor material.
Kinetics of face-centered cubic (FCC) phase evolution in equiatomic AlCoCrFeNi alloy has been studied in this work, measuring the phase fraction from X-ray diffraction (XRD). As-cast alloy showed a ...body-centered cubic (BCC)+B2 structure. Heat treatments performed at different temperatures showed the formation up-to 30 to 35 pct FCC phase between 1073 K and 1373 K. A systematic decrease in hardness from 540 to 390 HV
10
with increase in temperature suggested an increase in the FCC volume fraction. Kinetics of FCC evolution were analyzed using the Johnson–Mehl–Avrami–Kolmogorov equation and Arrhenius law to calculate the activation energy for the phase transformation. Furthermore, a time-temperature-transformation diagram was constructed from the isothermal transformation studies. Detailed microstructural investigation suggests faster kinetics of FCC phase formation near dendritic boundaries compared to interdendritic regions. The Kurdjumov–Sachs orientation relationship between FCC and BCC phases suggested a coherent interface between these phases. Results of the present study pave the way to decide on heat treatment practices in AlCoCrFeNi alloy.
Tissue engineering (TE) employs scaffolds as a structural support for initially seeding of cells followed by development of new tissues. Electrospun scaffolds generally function as a template of ...native extracellular matrix (ECM). The chemical composition of the scaffold and its surface morphology strongly influence the interaction between various cell types and materials. In this work, PCL and PCL/HPMC-based composite membranes with varying concentrations of HPMC (20–30% by weight) were fabricated using electrospinning technique. The membranes were evaluated for their surface, physio-chemical and biological properties. It was observed probably for the first time that blending of HPMC with PCL produced super-hydrophilic scaffolds. DSC studies confirmed the semi- crystalline nature of HPMC. PCL/HPMC composite scaffolds are found biocompatible from cytotoxicity assay. From the cell culture studies (apoptosis), PCL/HPMC composite scaffolds did not inhibit the adhesion of L929 cells due to their super-hydrophilic nature. The cell adhesion and spreading varied with HPMC concentration. PCL/HPMC (70/30) membranes showed highest cell adhesion among others due to its porous structure.
INTRODUCTION: Pandemics have historically posed significant threats to public health, with their impact often disproportionately affecting vulnerable populations, including slum dwellers. The ...convergence of densely populated under-resourced urban areas and the rapid spread of infectious diseases presents unique challenges and heightened risks to the health and well-being of individuals residing in these marginalized communities.
OBJECTIVES: The study aims to examine how the epidemic has affected slum residents. Additionally, the study intends to measure the stress and resiliency of such residents. For this reason, bibliometric analysis has been used.
METHODS: Such analysis has been carried out through the use of procedures like keyword selection, database selection, and research paper collection, search result refinement with selection and rejection criteria, and data collection and analysis. The databases Scopus and Dimension have been chosen to compile papers from 2020 to 2022. When searching for publications, terms like "slum dwellers," "coping strategy," "pandemic stress," and "slum resilience" are often used. Data analysis is done using the R software package Biblioshiny.
RESULTS: China, Spain, and Switzerland lead in average article citations and overall citations. Dominant themes are Covid, slum, health, and pandemic, with a focus on pandemic effects, health issues, and infection spread. The thematic map highlights "Covid and Slum Dwellers" as a central research theme, with thematic evolution from Covid and Population to themes like Slum, Surveys, and Participants, indicating a focus on data collection via interviews on the Covid impact on slum residents.
CONCLUSION: Several research papers were published to study the COVID-19 impact on slum dwellers from different dimensions. But their resilience strategy was less emphasised which can be a platform for emerging researchers. More studies are expected in this area. This study will assist policymakers in revising their approach to development and slump transformation.
The current work focuses on magnetohydrodynamic free convective flow mixed with radiation between vertical walls under the consequences of hall current as well as the induced magnetic field and is ...concerned with panel cooling for the aluminum smelting plant. It has been proposed that the fluid channel has a porous medium. The isothermal transport equations, which primarily concern mass, momentum, energy, and induced magnetic field, are solved analytically. After comparing the model findings with those from the literature, the effect of the different relevant parameters of the current model is gathered and presented. Hartmann number, Hall current on velocity components, current density, induced magnetic field, porosity, and Soret effect are all investigated for their effects. Due to the applied radiation field on plates, the influence of the radiation parameter has also been included. Under the effect of the Hall parameter, the velocity’s primary component is observed to increase; nevertheless, the secondary component has been shown to decrease. The Hall effect is observed to be reducing the generated magnetic field, and the Lorentz force Hartmann number decreases the flow. The magnitude of the velocity and current density is decreased because of the radiation parameter. Such methodology should be employed to get first-cut results and to analyze the system in a better way before the prototype development and demonstration.
We study the effect of a strong magnetic field on the properties of neutron stars with a quark-hadron phase transition. It is shown that the magnetic field prevents the appearance of a quark phase, ...enhances the leptonic fraction, decreases the baryonic density extension of the mixed phase and stiffens the total equation of state, including both the stellar matter and the magnetic field contributions. Two parametrizations of a density-dependent static magnetic field, increasing, respectively, fast and slowly with the density and reaching 2-4 X 1018 G in the centre of the star, are considered. The compact stars with strong magnetic fields have maximum mass configurations with larger masses and radii and smaller quark fractions. The parametrization of the magnetic field with density has a strong influence on the star properties.
Thermal management is an important parameter in an electronic packaging application. In this work, three different types of fillers such as natural graphite powder (Gr) of 50‐μm particle size, boron ...nitride powder (h‐BN) of 1‐μm size, and silver flakes (Ag) of 10‐μm particle size were used for thermal conductivity enhancement of neat epoxy resin. The thermal properties, rheology, and lap shear strength of the neat epoxy and its composite were investigated. The analysis showed that the loading of different wt% of Gr‐based fillers can effectively increase the thermal conductivity of the epoxy resin. It has also been observed that the thermal conductivity of the hybrid filler (Gr/h‐BN/Ag) reinforced epoxy adhesive composite increased six times greater than that of neat epoxy resin composite. Further, the viscosity of hybrid filler reinforced epoxy resin was found to be increased as compared with its virgin counterpart. The adhesive composite with optimized filler content was then subsequently subjected to determine single lap shear strength. The degree of filler dispersion and alignment in the matrix were determined by scanning electron microscopy (SEM) analysis.
NADPH-cytochrome P450 oxidoreductase (CYPOR) is essential for electron donation to microsomal cytochrome P450-mediated monooxygenation in such diverse physiological processes as drug metabolism ...(approximately 85–90% of therapeutic drugs), steroid biosynthesis, and bioactive metabolite production (vitamin D and retinoic acid metabolites). Expressed by a single gene, CYPOR’s role with these multiple redox partners renders it a model for understanding protein–protein interactions at the structural level. Polymorphisms in human CYPOR have been shown to lead to defects in bone development and steroidogenesis, resulting in sexual dimorphisms, the severity of which differs significantly depending on the degree of CYPOR impairment. The atomic structure of human CYPOR is presented, with structures of two naturally occurring missense mutations, V492E and R457H. The overall structures of these CYPOR variants are similar to wild type. However, in both variants, local disruption of H bonding and salt bridging, involving the FAD pyrophosphate moiety, leads to weaker FAD binding, unstable protein, and loss of catalytic activity, which can be rescued by cofactor addition. The modes of polypeptide unfolding in these two variants differ significantly, as revealed by limited trypsin digestion: V492E is less stable but unfolds locally and gradually, whereas R457H is more stable but unfolds globally. FAD addition to either variant prevents trypsin digestion, supporting the role of the cofactor in conferring stability to CYPOR structure. Thus, CYPOR dysfunction in patients harboring these particular mutations may possibly be prevented by riboflavin therapy in utero, if predicted prenatally, or rescued postnatally in less severe cases.
Over the past two decades, lead-free piezoceramics have been developed aiming to replace toxic lead-bearing lead zirconate titanate (PZT). A large number of lead-free piezo systems were explored ...during this period as evidenced from the huge number of publications. At this juncture, it was felt necessary to publish a review article focusing on material systems and processes delivering high
d
33
in order to give direction to future research for its further improvement equivalent to or higher than the
d
33
level delivered by PZT. The important lead-free piezo systems under consideration are: modified barium titanates such as barium calcium titanate zirconate (BCTZ), barium calcium tin titanate (BCSnT), barium calcium hafnium titanate (BCHfT), and potassium sodium niobate (KNN). In this article, an effort has been made to review the high piezoelectric properties achieved on the above lead-free piezo systems explaining the reasons and mechanisms behind high piezo properties and possible future directions of the research for further enhancement of properties.
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