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"Thakkar, M"
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Health 5.0 : concepts, challenges, and solutions
\"This book presents a detailed explanation of the concepts, taxonomy, and challenges in Healthcare 4.0 and provides frameworks and architectures for the adaptation and fusion of emerging technologies under Healthcare 5.0. The healthcare industry requires technological upgrades to provide precise, accurate, and automatic remote health monitoring and diagnosis. This reference book offers an early opportunity to explore emerging technologies and understand current issues, problems, and concepts. The primary audience for this book incorporates academicians, researcher scholars, IoMT developers, Cloud-Based health application designers, and medical practitioners who are engaged in providing healthcare services using recent technologies\"-- Provided by publisher.
BOOK
Reynolds-number dependence of the near-wall flow over irregular rough surfaces
The Reynolds-number dependence of turbulent channel flow over two irregular rough surfaces, based on scans of a graphite and a grit-blasted surface, is studied by direct numerical simulation. The aim is to characterise the changes in the flow in the immediate vicinity of and within the rough surfaces, an area of the flow where it is difficult to obtain experimental measurements. The average roughness heights and spatial correlation of the roughness features of the two surfaces are similar, but the two surfaces have a significant difference in the skewness of their height distributions, with the graphite sample being positively skewed (peak-dominated) and the grit-blasted surface being negatively skewed (valley-dominated). For both cases, numerical simulations were conducted at seven different Reynolds numbers, ranging from
$Re_{\\unicode[STIX]{x1D70F}}=90$
to
$Re_{\\unicode[STIX]{x1D70F}}=720$
. The positively skewed surface gives rise to higher friction factors than the negatively skewed surface in all cases. For the highest Reynolds numbers, the flow has values of the roughness function
$\\unicode[STIX]{x0394}U^{+}$
well in excess of
$7$
for both surfaces and the bulk flow profile has attained a constant shape across the full height of the channel except for the immediate vicinity of the roughness, which would indicate fully rough flow. However, the mean flow profile within and directly above the rough surface still shows considerable Reynolds-number dependence and the ratio of form to viscous drag continues to increase, which indicates that at least for some types of rough surfaces the flow retains aspects of the transitionally rough regime to values of
$\\unicode[STIX]{x0394}U^{+}$
or
$k^{+}$
well in excess of the values conventionally assumed for the transitionally to fully rough threshold. This is also reflected in the changes that the near-wall flow undergoes as the Reynolds number increases: the viscous sublayer, within which the surface roughness is initially buried, breaks down and regions of reverse flow intensify. At the highest Reynolds numbers, a layer of near-wall flow is observed to follow the contours of the local surface. The distribution of thickness of this ‘blanketing’ layer has a mixed scaling, showing that viscous effects are still significant in the near-wall flow.
Journal Article
Direct numerical simulation of turbulent channel flow over a surrogate for Nikuradse-type roughness
A tiled approach to rough surface simulation is used to explore the full range of roughness Reynolds numbers, from the limiting case of hydrodynamic smoothness up to fully rough conditions. The surface is based on a scan of a standard grit-blasted comparator, subsequently low-pass filtered and made spatially periodic. High roughness Reynolds numbers are obtained by increasing the friction Reynolds number of the direct numerical simulations, whereas low roughness Reynolds numbers are obtained by scaling the surface down and tiling to maintain a constant domain size. In both cases, computational requirements on box size, resolution in wall units and resolution per minimum wavelength of the rough surface are maintained. The resulting roughness function behaviour replicates to good accuracy the experiments of Nikuradse (1933 VDI-Forschungsheft, vol. 361), suggesting that the processed grit-blasted surface can serve as a surrogate for his sand-grain roughness, the precise structure of which is undocumented. The present simulations also document a monotonic departure from hydrodynamic smooth-wall results, which is fitted with a geometric relation, the exponent of which is found to be inconsistent with both the Colebrook formula and an earlier theoretical argument based on low-Reynolds-number drag relations.
Journal Article
Drought Assessment Using Remote Sensing Techniques in the Great Rann of Kachchh and Adjoining Areas of Thar Desert
Drought occurs when the amount of evaporation in a region is higher than the amount of rainfall. Studying drought in the Great Rann of Kachchh and adjoining areas of Thar Desert is crucial due to their arid climates, erratic rainfall, and frequent drought years. Remote sensing and GIS technologies offer rapidity, practicality, and precise monitoring capabilities for assessing drought conditions. Three spectral indices—Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Normalized Difference Salinity Index (NDSI) were investigated for the assessment of vegetated landscapes, water, and range of salinity present in the study area for the last decade (2013–2022). Spatial overlay analysis using parameters (NDVI, NDWI, and NDSI) has also been done to delineate the spatial and temporal variability of drought-vulnerable regions. Standard precipitation index (SPI) analysis has also been calculated for the estimation of the severity of drought events. Results show that the spectral indices and SPI values are significantly affected by the amount of average annual rainfall and our findings show that the region experienced four drought phases (2014, 2016, 2018, and 2021) during the last decade (2013–2022). The Kachchh region of Gujarat experiences severe and moderate drought events in 2018 and 2014 respectively while the Jalore and Barmer districts of Rajasthan experiences moderate drought events in 2018.
Journal Article
A Comparison of Classical Force-Fields for Molecular Dynamics Simulations of Lubricants
For the successful development and application of lubricants, a full understanding of their complex nanoscale behavior under a wide range of external conditions is required, but this is difficult to obtain experimentally. Nonequilibrium molecular dynamics (NEMD) simulations can be used to yield unique insights into the atomic-scale structure and friction of lubricants and additives; however, the accuracy of the results depend on the chosen force-field. In this study, we demonstrate that the use of an accurate, all-atom force-field is critical in order to; (i) accurately predict important properties of long-chain, linear molecules; and (ii) reproduce experimental friction behavior of multi-component tribological systems. In particular, we focus on n-hexadecane, an important model lubricant with a wide range of industrial applications. Moreover, simulating conditions common in tribological systems, i.e., high temperatures and pressures (HTHP), allows the limits of the selected force-fields to be tested. In the first section, a large number of united-atom and all-atom force-fields are benchmarked in terms of their density and viscosity prediction accuracy of n-hexadecane using equilibrium molecular dynamics (EMD) simulations at ambient and HTHP conditions. Whilst united-atom force-fields accurately reproduce experimental density, the viscosity is significantly under-predicted compared to all-atom force-fields and experiments. Moreover, some all-atom force-fields yield elevated melting points, leading to significant overestimation of both the density and viscosity. In the second section, the most accurate united-atom and all-atom force-field are compared in confined NEMD simulations which probe the structure and friction of stearic acid adsorbed on iron oxide and separated by a thin layer of n-hexadecane. The united-atom force-field provides an accurate representation of the structure of the confined stearic acid film; however, friction coefficients are consistently under-predicted and the friction-coverage and friction-velocity behavior deviates from that observed using all-atom force-fields and experimentally. This has important implications regarding force-field selection for NEMD simulations of systems containing long-chain, linear molecules; specifically, it is recommended that accurate all-atom potentials, such as L-OPLS-AA, are employed.
Journal Article
Nonequilibrium Molecular Dynamics Investigation of the Reduction in Friction and Wear by Carbon Nanoparticles Between Iron Surfaces
For the successful development and application of novel lubricant additives, a full understanding of their tribological behaviour at the nanoscale is required, but this can be difficult to obtain experimentally. In this study, nonequilibrium molecular dynamics simulations are used to examine the friction and wear reduction mechanisms of promising carbon nanoparticle friction modifier additives. Specifically, the friction and wear behaviour of carbon nanodiamonds (CNDs) and carbon nano-onions (CNOs) confined between α-iron slabs is probed at a range of coverages, pressures, and sliding velocities. At high coverage and low pressure, the nanoparticles do not indent into the α-iron slabs during sliding, leading to zero wear and a low friction coefficient. At low coverage and high pressure, the nanoparticles indent into, and plough through the slabs during sliding, leading to atomic-scale wear and a much higher friction coefficient. This contribution to the friction coefficient is well predicted by an expression developed for macroscopic indentation by Bowden and Tabor. Even at the highest pressures and lowest coverages simulated, both nanoparticles were able to maintain separation of the opposing slabs and reduce friction by approximately 75 % compared to when no nanoparticle was present, which agrees well with experimental observations. CNO nanoparticles yielded a lower indentation (wear) depth and lower friction coefficients at equal coverage and pressure with respect to CND, making them more attractive friction modifier additives. Potential changes in behaviour on harder and softer surfaces are also discussed, together with the implications that these results have in terms of the application of the studied nanoparticles as lubricants additives.
Journal Article
Alcohol disrupts sleep homeostasis
Alcohol is a potent somnogen and one of the most commonly used “over the counter” sleep aids. In healthy non-alcoholics, acute alcohol decreases sleep latency, consolidates and increases the quality (delta power) and quantity of NREM sleep during the first half of the night. However, sleep is disrupted during the second half. Alcoholics, both during drinking periods and during abstinences, suffer from a multitude of sleep disruptions manifested by profound insomnia, excessive daytime sleepiness, and altered sleep architecture. Furthermore, subjective and objective indicators of sleep disturbances are predictors of relapse. Finally, within the USA, it is estimated that societal costs of alcohol-related sleep disorders exceeds $18 billion. Thus, although alcohol-associated sleep problems have significant economic and clinical consequences, very little is known about how and where alcohol acts to affect sleep. In this review, we have described our attempts to unravel the mechanism of alcohol-induced sleep disruptions. We have conducted a series of experiments using two different species, rats and mice, as animal models. We performed microdialysis, immunohistochemical, pharmacological, sleep deprivation and lesion studies which suggest that the sleep-promoting effects of alcohol may be mediated via alcohol's action on the mediators of sleep homeostasis: adenosine (AD) and the wake-promoting cholinergic neurons of the basal forebrain (BF). Alcohol, via its action on AD uptake, increases extracellular AD resulting in the inhibition of BF wake-promoting neurons. Since binge alcohol consumption is a highly prevalent pattern of alcohol consumption and disrupts sleep, we examined the effects of binge drinking on sleep-wakefulness. Our results suggest that disrupted sleep homeostasis may be the primary cause of sleep disruption observed following binge drinking. Finally, we have also shown that sleep disruptions observed during acute withdrawal, are caused due to impaired sleep homeostasis. In conclusion, we suggest that alcohol may disrupt sleep homeostasis to cause sleep disruptions.
Journal Article
Geological heritage and geotourism potential of Udaipur region, Rajasthan, India
The Rajasthan state of India is always been a region of diversity in its geology, geomorphology, flora, fauna, ethnology, history, civilization, post-Christ historical, industrial, and war-defense development. The area of unending climatic changes from fertile lands of the Himalayan fed Vedic Saraswati, pre- and post-Indus civilization to long-run aridity in the Thar Desert made the Rajasthani people with incredibly strong minds. The Pb-Cu–Zn and other dozens of metals and innumerable non-metals of the Aravalli region one of the oldest orogenic regions of the world have enriched the treasures of all the Indian empires from 4000 BC until today. Udaipur and the surrounding area focused here are a small part of Rajasthan but housed almost all kinds of geological features; viz., Precambrian orogenic, collision tectonics, ophiolite suites, carbonatites, huge deep-water sediments to shallow shelf carbonates, miogeosynclines, and ancient global oxidation events, as well as the events about algal blooms in the world, are remarkably preserved in this small region which we classified into four different traverses with 27 geological heritage sites. The micro, macro, and mega structures, drawn and described in almost all books of structural geology and metamorphic and igneous petrology, are classically exposed in the Udaipur region that merits its place among the best geoparks of the world. Several geological exposures of this region have given prolific knowledge to a number of renowned geologists in India as well as the world. We propose this region to be conserved for future geologists, researchers, and students, as well as for common curious tourists.
Journal Article
Tectonic evolution and stress pattern of South Wagad Fault at the Kachchh Rift Basin in western India
We describe a study of the E–W-trending South Wagad Fault (SWF) complex at the eastern part of the Kachchh Rift Basin (KRB) in Western India. This basin was filled during Late Cretaceous time, and is presently undergoing tectonic inversion. During the late stage of the inversion cycle, all the principal rift faults were reactivated as transpressional strike-slip faults. The SWF complex shows wrench geometry of an anastomosing en échelon fault, where contractional and extensional segments and offsets alternate along the Principal Deformation Zone (PDZ). Geometric analysis of different segments of the SWF shows that several conjugate faults, which are a combination of R synthetic and R’ antithetic, propagate at a short distance along the PDZ and interact, generating significant fault slip partitioning. Surface morphology of the fault zone revealed three deformation zones: a 500 m to 1 km wide single fault zone; a 5–6 km wide double fault zone; and a c. 500 m wide diffuse fault zone. The single fault zone is represented by a higher stress accumulation which is located close to the epicentre of the 2001 Bhuj earthquake of M
w 7.7. The double fault zone represents moderate stress at releasing bends bounded by two fault branches. The diffuse fault zone represents a low-stress zone where several fault branches join together. Our findings are well corroborated with the available geological and seismological data.
Journal Article
Electrochemical Sensor Platform for Rapid Detection of Foodborne Toxins
Zearalenone (ZEA), a potent mycotoxin commonly found in contaminated grains, presents a serious threat to food safety and public health. Conventional detection methods, including culture-based assays and laboratory-bound analytical tools, are often time-consuming, require specialized infrastructure, and lack portability, limiting their utility for rapid, on-site screening. In response, this study introduces a compact, real-time electrochemical sensing platform for the swift and selective detection of ZEA in corn flour matrices. Utilizing a non-faradaic, label-free approach based on Electrochemical Impedance Spectroscopy (EIS), the sensor leverages ZEA-specific antibodies to achieve rapid detection within 5 min. The platform demonstrates a low detection limit of 0.05 ng/mL, with a broad dynamic range from 0.1 ng/mL to 25.6 ng/mL. Reproducibility tests confirm consistent performance, with both inter- and intra-assay variation remaining under a 20% coefficient of variation (%CV). Comparative evaluation with standard benchtop systems underscores its accuracy and field applicability. This portable and user-friendly device provides a powerful tool for real-time mycotoxin monitoring, offering significant potential for improving food safety practices and enabling point-of-need testing in resource-limited settings.
Journal Article