The Finite Element Method in Engineering is the only book to provide a broad overview of the underlying principles of finite element analysis and where it fits into the larger context of other ...mathematically based engineering analytical tools. This is an updated and improved version of a finite element text long noted for its practical applications approach, its readability, and ease of use. Students will find in this textbook a thorough grounding of the mathematical principles underlying the popular, analytical methods for setting up a finite element solution based on mathematical equations. The book provides a host of real-world applications of finite element analysis, from structural design to problems in fluid mechanics and thermodynamics. It has added new sections on the assemblage of element equations, as well as an important new comparison between finite element analysis and other analytical methods showing advantages and disadvantages of each. This book will appeal to students in mechanical, structural, electrical, environmental and biomedical engineering.
State-of-art review on hybrid nanofluids Ranga Babu, J.A.; Kumar, K. Kiran; Srinivasa Rao, S.
Renewable & sustainable energy reviews,
09/2017, Letnik:
77
Journal Article
Recenzirano
Nanofluids have found crucial presence in heat transfer applications with their promising characteristics that can be controlled as per requirements. Nanofluids possess unique characteristics that ...have attracted many researchers over the past two decades to design new thermal systems for different engineering applications. Mono nanofluids, prepared with a single kind of nanoparticles, possess certain specific benefits owing to the properties of the suspended nanoparticle. However to further improve the characteristics of nanofluids, that could possess a number of favourable characteristics, researchers developed a new generation heat transfer fluid called hybrid nanofluid. Hybrid nanofluids are prepared either by dispersing dissimilar nanoparticles as individual constituents or by dispersing nanocomposite particles in the base fluid. Hybrid nanofluids may possess better thermal network and rheological properties due to synergistic effect. Researchers, to adjudge the advantages, disadvantages and their suitability for diversified applications, are extensively investigating the behavior and properties of these hybrid nanofluids. This review summarizes the contemporary investigations on synthesis, thermo-physical properties, heat transfer characteristics, hydrodynamic behavior and fluid flow characteristics reported by researchers on different hybrid nanofluids. This review also outlines the applications and challenges associated with hybrid nanofluid and makes some suggestions for future scope of research in this area.
•Synthesis methods of hybrid nanocomposites are presented.•Correlations for thermophysical properties of mono nanofluids and hybrid nanofluids are thoroughly discussed.•Heat transfer and rheological characteristics of various hybrid nanofluids are intensively and comprehensively analyzed.•Applications and challenges of hybrid nanofluids are explored.
Small intestinal bacterial overgrowth is defined as the presence of excessive numbers of bacteria in the small bowel, causing gastrointestinal symptoms. This guideline statement evaluates criteria ...for diagnosis, defines the optimal methods for diagnostic testing, and summarizes treatment options for small intestinal bacterial overgrowth. This guideline provides an evidence-based evaluation of the literature through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process. In instances where the available evidence was not appropriate for a formal GRADE recommendation, key concepts were developed using expert consensus.
Silicon (Si) nanoparticles (NPs) and self-organized high spatial frequency laser (HSFL) induced periodic surface structures were fabricated by means of femtosecond ablation of bulk Si target in ...acetone. The ablation was performed with ∼40 fs (fwhm) pulses and different input energies of ∼500, ∼200, ∼150, ∼100, ∼50, and ∼10 μJ. Fabricated NPs and nanostructures (NSs) were characterized by UV–visible absorption spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. The average sizes of the NPs were estimated to be in the 4–135 nm range. From the PL studies of Si NPs of different sizes, we have observed a size-dependent shift toward blue spectral region. We could tune the observed PL peak in the spectral range of 440–515 nm. The crystalline and amorphous nature of the Si nanoparticles and nanostructures was investigated using selected area electron diffraction and Raman spectra. Complex refractive index, conduction band electron density of the Si NPs, estimated by measuring the effective spot size corresponding to each input energies, were observed to play a crucial role in determining the periodicity of HSFL induced periodic surface structures. Experimentally measured periodicity of gratings was in good agreement with the theory.
•Coronavirus disease 2019 (COVID-19) has emerged as a global health threat.•Number of suicidal deaths during times of COVID-19 is rising though data is limited.•Pandemics lead to several risk factors ...for suicidality like isolation, loneliness, economic fallout, domestic abuse, stigma and fear.•Biological vulnerabilities (family history of suicide, substance use, etc.) and psychosocial risks (migration, old age, low socio-economic class, etc.) amplify the suicidal risks of pandemics.•Stress and immune reaction to infections like COVID-19 are hypothesized as possible linking pathways to suicidal risk.•Suicide-prevention is discussed as an integral part of public health response to pandemics.
The Coronavirus disease 2019 (COVID-19) has emerged as a new global health threat. By increasing the risk of isolation, fear, stigma, abuse and economic fallout, COVID-19 has led to increase in risk of psychiatric disorders, chronic trauma and stress, which eventually increase suicidality and suicidal behavior. There is limited data on association of pandemics and suicides. Cases of suicides have been rising since COVID-19 first emerged in China. The association between suicides and pandemics can possibly be explained through various models like Durkheim's theory, Joiner's interpersonal theory, social stress theory, biological theories, etc. The frontline workers, elderly, migrants, homeless, socio-economically impoverished classes as well as those with pre-existing mental disorders, substance abuse and family history of suicides are at higher risk. Suicides are preventable and need early detection, awareness and socio-culturally tailored interventions. This narrative review draws global perspectives on the association of suicidality and pandemics, the theories and risk factors related to same based on the available evidence. It also hypothesizes neuroimmunity and immune based risk factors as possible links between the psychosocial vulnerabilities and suicide during outbreaks like COVID-19. Proposed strategies of suicide-prevention, as an integral part of public health response to the pandemic are subsequently discussed.
To compare the diagnostic abilities of vessel density measurements of the optic nerve head (ONH), peripapillary and macular regions on optical coherence tomography (OCT) angiography in eyes with ...primary open angle glaucoma (POAG) with that of the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (GCC) thickness measurements.
In a cross sectional study, 78 eyes of 50 control subjects and 117 eyes of 67 POAG patients underwent vessel density and structural measurements with spectral domain OCT. POAG was diagnosed based on the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities in ONH, peripapillary and macular regions were compared with rim area, RNFL and GCC thickness.
The AUC (sensitivity at 95% specificity) of average vessel densities within the ONH, peripapillary and macular region were 0.77 (31%), 0.85 (56%) and 0.70 (18%) respectively. The same of ONH rim area, average RNFL and GCC thickness were 0.94 (83%), 0.95 (72%) and 0.93 (62%) respectively. AUCs of vessel densities were significantly lower (p<0.05) than that of the corresponding structural measurements. Pre-treatment IOP (coefficient: 0.08) affected (p<0.05) the AUC of ONH vessel density but not of any other vessel density or structural measurements.
Diagnostic abilities of ONH, peripapillary and the macular vessel densities in POAG were significantly lower than ONH rim area, peripapillary RNFL and macular GCC measurements respectively. At fixed levels of glaucoma severity, the diagnostic ability of the ONH vessel density was significantly greater in eyes with higher pre-treatment IOP.
Changing rainfall patterns have significant effect on water resources, agriculture output in many countries, especially the country like India where the economy depends on rain-fed agriculture. ...Rainfall over India has large spatial as well as temporal variability. To understand the variability in rainfall, spatial–temporal analyses of rainfall have been studied by using 107 (1901–2007) years of daily gridded India Meteorological Department (IMD) rainfall datasets. Further, the validation of IMD precipitation data is carried out with different observational and different reanalysis datasets during the period from 1989 to 2007. The Global Precipitation Climatology Project data shows similar features as that of IMD with high degree of comparison, whereas Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation data show similar features but with large differences, especially over northwest, west coast and western Himalayas. Spatially, large deviation is observed in the interior peninsula during the monsoon season with National Aeronautics Space Administration-Modern Era Retrospective-analysis for Research and Applications (NASA-MERRA), pre-monsoon with Japanese 25 years Re Analysis (JRA-25), and post-monsoon with climate forecast system reanalysis (CFSR) reanalysis datasets. Among the reanalysis datasets, European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim) shows good comparison followed by CFSR, NASA-MERRA, and JRA-25. Further, for the first time, with high resolution and long-term IMD data, the spatial distribution of trends is estimated using robust regression analysis technique on the annual and seasonal rainfall data with respect to different regions of India. Significant positive and negative trends are noticed in the whole time series of data during the monsoon season. The northeast and west coast of the Indian region shows significant positive trends and negative trends over western Himalayas and north central Indian region.
Background: The COVID-19 pandemic has led to a complete shut-down of the entire world and almost all the countries are presently in a "lockdown" mode. While the lockdown strategy is an essential step ...to curb the exponential rise of COVID-19 cases, the impact of the same on mental health is not well known.
Aim: This study aimed to evaluate the psychological impact of lockdown due to COVID-19 pandemic on the general public with an objective to assess the prevalence of depression, anxiety, perceived stress, well-being, and other psychological issues.
Materials and Methods: It was an online survey conducted under the aegis of the Indian Psychiatry Society. Using the Survey Monkey platform, a survey link was circulated using the Whatsapp. The survey questionnaire included perceived stress scale, Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, Warwick-Edinburgh Mental Well-being Scale to assess perceived stress, anxiety, depression, and mental well-being, respectively. The survey link was circulated starting from April 6, 2020 and was closed on April 24, 2020.
Results: During the survey, a total of 1871 responses were collected, of which 1685 (90.05%) responses were analyzed. About two-fifth (38.2%) had anxiety and 10.5% of the participants had depression. Overall, 40.5% of the participants had either anxiety or depression. Moderate level of stress was reported by about three-fourth (74.1%) of the participants and 71.7% reported poor well-being.
Conclusions: The present survey suggests that more than two-fifths of the people are experiencing common mental disorders, due to lockdown and the prevailing COVID-19 pandemic. This finding suggests that there is a need for expanding mental health services to everyone in the society during this pandemic situation.
We propose the use of a machine learning algorithm to improve possible COVID-19 case identification more quickly using a mobile phone-based web survey. This method could reduce the spread of the ...virus in susceptible populations under quarantine.
Summary
Background
Dietary fibre supplements have been advocated for the management of chronic constipation (CC) and irritable bowel syndrome (IBS). Recently, a fermentable oligosaccharide, ...disaccharide, monosaccharide and polyol (FODMAP) restricted diet has been recommended for IBS.
Aim
To systematically examine recent evidence for dietary interventions with fibre in CC and IBS and FODMAP‐restricted diet in IBS, and provide recommendations.
Methods
We searched PUBMED, MEDLINE, OVID and COCHRANE databases from 2004 to 2014. Published studies in adults with CC and IBS and constipation‐predominant IBS (IBS‐C) that compared fibre with placebo/alternative and FODMAP‐restricted diet with alternative were included.
Results
Of 550 potentially eligible clinical trials on fibre, 11 studies were found and of 23 potentially eligible studies on FODMAPs, six were found. A meta‐analysis was not performed due to heterogeneity and methodological quality. Fibre was beneficial in 5/7 studies in CC and 3/3 studies in IBS‐C. FODMAP‐restricted diet improved overall IBS symptoms in 4/4 and IBS‐C symptoms in 1/3 studies and three studies did not meet inclusion criteria. There were significant disparities in subject selection, interventions and outcome assessments in both fibre and FODMAPs studies.
Conclusions
Fibre supplementation is beneficial in mild to moderate CC and IBS‐C, although larger, more rigorous and long‐term RCTs are needed (Fair evidence–Level II, Grade B). Although the FODMAP‐restricted diet may be effective in short‐term management of selected patients with IBS (Fair evidence–Level II, Grade C) and IBS‐C (Poor evidence–Level III, Grade C), more rigorous trials are needed to establish long‐term efficacy and safety, particularly on colonic health and microbiome.
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