138 research outputs found

    STUDYING THE EFFECTS OF INITIAL CRACK ANGLE ON THE CRACK PROPAGATION IN GRAPHENE NANO-RIBBON THROUGH MOLECULAR DYNAMICS SIMULATIONS

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    In this research, we have worked on the brittle fracture of graphene nano-ribbon to explore the behavior of crack propagation at different crack angles. We have performed classical Molecular Dynamics simulations using LAMMPS at ten different crack angles between 0 degrees and 45 degrees, in an increment of 5 degrees to observe the parameters that dominate the crack path. The graphene nanoribbon is loaded in the zigzag direction by pulling it in the armchair direction with a pre-existing crack in the center. We have used OVITO for the visualization of the simulation. AIREBO potential is employed in this work because it is extensively used in the fracture of graphene with different loading conditions and temperatures. The crack path is determined for all ten nanoribbons and the nanoribbon with a crack at 25° turned out to be the weakest because of the sharp crack tip and crack shape. The results are validated with the published results and are in accordance with them

    SPECIFIC ABSORPTION RATE (SAR) DUE TO VARIATION IN FREQUENCY ON HUMAN BODY TISSUES NEAR RADIO BROADCASTING ANTENNA

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     Objective: Theoretical studies are made for the specific absorption rate (SAR) in consequences of induced electric fields due to radio broadcastingtower at 100 m distance.Methods: The penetrated electric fields and SAR inside human body tissues are calculated for different frequencies. A comparison is made with theinternational safety guidelines given by World Health Organization and International Commission on Non-ionizing Radiation Protection.Results: The penetrated electric field and SAR by some tissues at frequencies 1377, 1404, 1485, 1512, and 1530 kHz of electromagnetic waves arecomputed.Conclusion: According to permissible limit the frequencies 1377, 1404, 1485, 1512 and 1530 kHz of 20 kW EM radiations at 100 m distance are safefor tissues bladder, blood vessel, brain white matter, fat, heart, lung outer and mucous membrane at depths 0.1, 0.2 and 0.3 mm respectively. And thisradiation is harmful for blood, body fluid, cerebella spinal fluid, eye sclera, gall bladder, gall bladder bile, gland, lung inner, lymph, mucous membrane,pancreas, stomach, testis and vitreous humor tissues at depths 0.1, 0.2 and 0.3 mm, respectively.Keywords: Induced electric field, Specific absorption rate, Thermoregulatory mechanism and broadcasting antenna.Â

    Methods of obtaining smooth surface in 2D/3D surface reconstruction

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    Surface reconstruction is an emergent research area in the field of computer aided design and manufacturing. There are various methods / algorithms which are working considerably well for surface reconstruction problem but we cannot say to the best of our knowledge that we got all the solutions. Missing surface can be repaired either by surface patch or by extending boundary curves. However, in both cases, surface smoothening problem arises in form of flat surface. The present paper has been tried to offer a solution to above problem which makes the curve smoother

    Effect of Groove Location on Pressure Profile of Twin Axial Groove Journal Bearing

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    The main aim of current work is to analyze the influence of groove location on the pressure profile of the hybrid journal bearing. The objective is to develop solution algorithm and computer program which will provide pressure profile developed in the space of clearance of bearing having a given value of Somerfield number. The solution algorithm shall also provide three dimensional pressure profiles of the bearing for different groove location. It was found that groove location with respect to the loading line strongly influences the parameters of performance because of the stronger groove interference in the pressurized hydrodynamic field. The comparison of circumferential pressure with angular location from +X-axis is shown for the ratio of length to diameter which comes out to be 0.5, the clearance ratio (C/R) is found to be 0.00294 while 1125 rpm is the speed. The groove axes optimal location lies between 60° to 90° (  g =0°) to the line of loading

    Effect of Groove Location on Pressure Profile of Twin Axial Groove Journal Bearing

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    1049-1052The main aim of current work is to analyze the influence of groove location on the pressure profile of the hybrid journal bearing. The objective is to develop solution algorithm and computer program which will provide pressure profile developed in the space of clearance of bearing having a given value of Somerfield number. The solution algorithm shall also provide three dimensional pressure profiles of the bearing for different groove location. It was found that groove location with respect to the loading line strongly influences the parameters of performance because of the stronger groove interference in the pressurized hydrodynamic field. The comparison of circumferential pressure with angular location from +X-axis is shown for the ratio of length to diameter which comes out to be 0.5, the clearance ratio (C/R) is found to be 0.00294 while 1125 rpm is the speed. The groove axes optimal location lies between 60° to 90° (∝1 g =0°) to the line of loading

    Origin and spread of human mitochondrial DNA haplogroup U7

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    Human mitochondrial DNA haplogroup U is among the initial maternal founders in Southwest Asia and Europe and one that best indicates matrilineal genetic continuity between late Pleistocene hunter-gatherer groups and present-day populations of Europe. While most haplogroup U subclades are older than 30 thousand years, the comparatively recent coalescence time of the extant variation of haplogroup U7 (~16–19 thousand years ago) suggests that its current distribution is the consequence of more recent dispersal events, despite its wide geographical range across Europe, the Near East and South Asia. Here we report 267 new U7 mitogenomes that – analysed alongside 100 published ones – enable us to discern at least two distinct temporal phases of dispersal, both of which most likely emanated from the Near East. The earlier one began prior to the Holocene (~11.5 thousand years ago) towards South Asia, while the later dispersal took place more recently towards Mediterranean Europe during the Neolithic (~8 thousand years ago). These findings imply that the carriers of haplogroup U7 spread to South Asia and Europe before the suggested Bronze Age expansion of Indo-European languages from the Pontic-Caspian Steppe region

    Measuring routine childhood vaccination coverage in 204 countries and territories, 1980-2019 : a systematic analysis for the Global Burden of Disease Study 2020, Release 1

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    Background Measuring routine childhood vaccination is crucial to inform global vaccine policies and programme implementation, and to track progress towards targets set by the Global Vaccine Action Plan (GVAP) and Immunization Agenda 2030. Robust estimates of routine vaccine coverage are needed to identify past successes and persistent vulnerabilities. Drawing from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020, Release 1, we did a systematic analysis of global, regional, and national vaccine coverage trends using a statistical framework, by vaccine and over time. Methods For this analysis we collated 55 326 country-specific, cohort-specific, year-specific, vaccine-specific, and dosespecific observations of routine childhood vaccination coverage between 1980 and 2019. Using spatiotemporal Gaussian process regression, we produced location-specific and year-specific estimates of 11 routine childhood vaccine coverage indicators for 204 countries and territories from 1980 to 2019, adjusting for biases in countryreported data and reflecting reported stockouts and supply disruptions. We analysed global and regional trends in coverage and numbers of zero-dose children (defined as those who never received a diphtheria-tetanus-pertussis [DTP] vaccine dose), progress towards GVAP targets, and the relationship between vaccine coverage and sociodemographic development. Findings By 2019, global coverage of third-dose DTP (DTP3; 81.6% [95% uncertainty interval 80.4-82 .7]) more than doubled from levels estimated in 1980 (39.9% [37.5-42.1]), as did global coverage of the first-dose measles-containing vaccine (MCV1; from 38.5% [35.4-41.3] in 1980 to 83.6% [82.3-84.8] in 2019). Third- dose polio vaccine (Pol3) coverage also increased, from 42.6% (41.4-44.1) in 1980 to 79.8% (78.4-81.1) in 2019, and global coverage of newer vaccines increased rapidly between 2000 and 2019. The global number of zero-dose children fell by nearly 75% between 1980 and 2019, from 56.8 million (52.6-60. 9) to 14.5 million (13.4-15.9). However, over the past decade, global vaccine coverage broadly plateaued; 94 countries and territories recorded decreasing DTP3 coverage since 2010. Only 11 countries and territories were estimated to have reached the national GVAP target of at least 90% coverage for all assessed vaccines in 2019. Interpretation After achieving large gains in childhood vaccine coverage worldwide, in much of the world this progress was stalled or reversed from 2010 to 2019. These findings underscore the importance of revisiting routine immunisation strategies and programmatic approaches, recentring service delivery around equity and underserved populations. Strengthening vaccine data and monitoring systems is crucial to these pursuits, now and through to 2030, to ensure that all children have access to, and can benefit from, lifesaving vaccines. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe

    Global, regional, and national burden of stroke and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Background Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels. Methods We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes combined, and stratified by sex, age group, and World Bank country income level. Findings In 2019, there were 12·2 million (95% UI 11·0–13·6) incident cases of stroke, 101 million (93·2–111) prevalent cases of stroke, 143 million (133–153) DALYs due to stroke, and 6·55 million (6·00–7·02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11·6% [10·8–12·2] of total deaths) and the third-leading cause of death and disability combined (5·7% [5·1–6·2] of total DALYs) in 2019. From 1990 to 2019, the absolute number of incident strokes increased by 70·0% (67·0–73·0), prevalent strokes increased by 85·0% (83·0–88·0), deaths from stroke increased by 43·0% (31·0–55·0), and DALYs due to stroke increased by 32·0% (22·0–42·0). During the same period, age-standardised rates of stroke incidence decreased by 17·0% (15·0–18·0), mortality decreased by 36·0% (31·0–42·0), prevalence decreased by 6·0% (5·0–7·0), and DALYs decreased by 36·0% (31·0–42·0). However, among people younger than 70 years, prevalence rates increased by 22·0% (21·0–24·0) and incidence rates increased by 15·0% (12·0–18·0). In 2019, the age-standardised stroke-related mortality rate was 3·6 (3·5–3·8) times higher in the World Bank low-income group than in the World Bank high-income group, and the age-standardised stroke-related DALY rate was 3·7 (3·5–3·9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62·4% of all incident strokes in 2019 (7·63 million [6·57–8·96]), while intracerebral haemorrhage constituted 27·9% (3·41 million [2·97–3·91]) and subarachnoid haemorrhage constituted 9·7% (1·18 million [1·01–1·39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79·6 million [67·7–90·8] DALYs or 55·5% [48·2–62·0] of total stroke DALYs), high body-mass index (34·9 million [22·3–48·6] DALYs or 24·3% [15·7–33·2]), high fasting plasma glucose (28·9 million [19·8–41·5] DALYs or 20·2% [13·8–29·1]), ambient particulate matter pollution (28·7 million [23·4–33·4] DALYs or 20·1% [16·6–23·0]), and smoking (25·3 million [22·6–28·2] DALYs or 17·6% [16·4–19·0]). Interpretation The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest-growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries.publishedVersio

    Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017

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    Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe
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