29 research outputs found

    Multi Target Optimization of Turbojet Engine with Multi Target Genetic Algorithm

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    Abstract: In this paper, Turbojet engine will be optimized in ideal condition by multi target genetic algorithm. Target functions are specific thrust (ST), specific fuel consumption (SFC) and thermal efficiency (η t ) that will be optimized simultaneously according to design variables and in two by two way and their Pareto points will be showed. Design variables included inlet Mach number and total compressor pressure ratio. Then according to Pareto points important relations between target functions will be introduced. It is obvious that these relations without using these methods are inaccessible

    The Mineral Biochar Alters the Biochemical and Microbial Properties of the Soil and the Grain Yield of Hordeum vulgare L. under Drought Stress

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    Biochar improves soil physical, biochemical, and microbial properties, leading to the amelioration of soil fertility, which, in turn, results in better growth and yield in crop plants. The current study aimed to evaluate whether using different levels of biochar can enhance soil characteristics and plant attributes. Accordingly, an experimental study was conducted in 2022 using a randomized complete block design with four replications (n = 4) in the experimental glasshouse of the University of Zanjan, in which two regimes of irrigation (D0, full irrigation as the control; D1, water scarcity was applied immediately after the flowering stage for two weeks) and four levels of natural mineral biochar (0% as the control treatment, 0.25, 0.5, and 1% of soil weight) were applied. The results indicated that drought substantially decreased the organic carbon content of the soil and the grain yield while increasing the available phosphorous, soil carbohydrate content, and microbial biomass of the soil. Biochar could considerably alter the means of the studied soil quality parameters and the barley grain yield. Adding biochar could be considered a valid strategy to increase the resistance of plants to drought

    Call to Action: SARS-CoV-2 and CerebrovAscular DisordErs (CASCADE)

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    Background and purpose: The novel severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), now named coronavirus disease 2019 (COVID-19), may change the risk of stroke through an enhanced systemic inflammatory response, hypercoagulable state, and endothelial damage in the cerebrovascular system. Moreover, due to the current pandemic, some countries have prioritized health resources towards COVID-19 management, making it more challenging to appropriately care for other potentially disabling and fatal diseases such as stroke. The aim of this study is to identify and describe changes in stroke epidemiological trends before, during, and after the COVID-19 pandemic. Methods: This is an international, multicenter, hospital-based study on stroke incidence and outcomes during the COVID-19 pandemic. We will describe patterns in stroke management, stroke hospitalization rate, and stroke severity, subtype (ischemic/hemorrhagic), and outcomes (including in-hospital mortality) in 2020 during COVID-19 pandemic, comparing them with the corresponding data from 2018 and 2019, and subsequently 2021. We will also use an interrupted time series (ITS) analysis to assess the change in stroke hospitalization rates before, during, and after COVID-19, in each participating center. Conclusion: The proposed study will potentially enable us to better understand the changes in stroke care protocols, differential hospitalization rate, and severity of stroke, as it pertains to the COVID-19 pandemic. Ultimately, this will help guide clinical-based policies surrounding COVID-19 and other similar global pandemics to ensure that management of cerebrovascular comorbidity is appropriately prioritized during the global crisis. It will also guide public health guidelines for at-risk populations to reduce risks of complications from such comorbidities. © 202

    Prevalence of Hepatitis G virus (HGV) in High-Risk Groups and Blood Donors in Tehran, Iran

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    The hepatitis G virus (HGV) is a newly discovered RNA virus, which is associated with acute or chronic hepatitis. A survey was conducted in thalassemic patients, intravenous drug users (IVDU) and blood donors aiming to investigate the prevalence of hepatitis G virus (HGV) infection in these groups in Tehran. The presence of HGV RNA in these populations was determined using reverse transcriptase polymerase chain reaction (RT-PCR) of the 5’ non-coding region (NCR) of the virus. One percent of blood donors, 12.9% of thalassemics and 8.8% of the IVDUs, were infected with HGV. Twenty-five percent of HGV positive cases were also positive for HCV and none were positive for HBV-DNA. The greatest proportion of HCV positive cases were seen in IVDU group (67.4%) being the only HIV positive group (8.8%). In conclusion our study showed that HGV infection occurs with relatively intermediate frequency among thalassemics and IVDUs in Iran and a higher rate of HGV-RNA was observed in older IVDUs

    Seismological and field observations from the 1990 November 6 Furg (Hormozgan) earthquake: a rare case of surface rupture in the Zagros mountains of Iran.

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    We document a unique example of a co-seismic surface rupture in the Zagros mountains of SE Iran. Using P- and SH-waveform inversion, aftershock distributions and field observations we show that the Mw 6.4 1990 November 6 Furg (Hormozgan) earthquake was associated with ∼15 km of south-facing surface ruptures with an average vertical displacement of ∼1 m. Earthquakes of Mw 6–7 are common in the Zagros mountains of Iran. However, no co-seismic surface ruptures associated with thrust faulting have been reported before now, and blind thrusting appears to be more common. Source parameters determined from seismology and measurements from the surface ruptures indicate slip on a fault dipping ∼30◦N. Although there is likely to be considerable uncertainty in at least some locations, the aftershock activity measured in the month following the earthquake appears to be broadly confined to a diffuse area around the northward-dipping fault. The geomorphology of the epicentral region contains indications of both long-term Quaternary uplift and cumulative fault scarps from repeated earthquakes. The Furg earthquake probably occurred on a reactivated section of the High Zagros fault, a geological suture from the early history of the Iran–Eurasia collision. The 1990 earthquake is likely to have ruptured to the surface because of its unusual location in the High Zagros zone, away from the present-day focus of seismic activity in the Simply Folded zone of the Zagros. It is possible that other sections of the High Zagros sutures still have the potential to generate earthquakes

    Mashhad stroke and heart atherosclerotic disorder (MASHAD) study: design, baseline characteristics and 10-year cardiovascular risk estimation

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    Objective: The Mashhad stroke and heart atherosclerotic disorder (MASHAD) study is a 10-year cohort study that aims to evaluate the impact of various genetic, environmental, nutritional and psychosocial risk factors on the incidence of cardiovascular events among an urban population in eastern Iran. Methods: The MASHAD study comprises a cohort of 9704 individuals aged 35-65 years using a stratified cluster random sampling design. This cohort will be followed up until 2020, with follow-up examinations being undertaken every 3 years. Ten-year cardiovascular disease (CVD) risk estimation was determined using NCEP ATP III criteria. Results: Overall, 88.4 of women and 79.2 of men (P 20 were observed to be 86.6, 11 and 2.5 , respectively. Predicted risk of CVD > 10 using the Framingham algorithm was considerably higher in men compared to women. Overall, 9.5 95 % confidence interval (CI) 8.9�10.1 % of our subjects had prevalent CAD. Conclusion: The prevalence of CVD risk factors within our population is high compared to Western countries, indicating the necessity for interventional risk modifications. © 2015, Swiss School of Public Health

    Correlations between COVID-19 and burden of dementia: An ecological study and review of literature

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    INTRODUCTION: Current evidence on the association between COVID-19 and dementia is sparse. This study aims to investigate the associations between COVID-19 caseload and the burden of dementia. METHODS: We gathered data regarding burden of dementia (disability-adjusted life years [DALYs] per 100,000), life expectancy, and healthy life expectancy (HALE) from the Global Burden of Disease (GBD) 2017 study. We obtained COVID-19 data from Our World in Data database. We analyzed the association of COVID-19 cases and deaths with the burden of dementia using Spearman's rank correlation coefficient. RESULTS: Globally, we found significant positive (p < .001) correlations between life expectancy (r = 0.60), HALE (r = 0.58), and dementia DALYs (r = 0.46) with COVID-19 caseloads. Likewise, we found similar correlations between life expectancy (r = 0.60), HALE (r = 0.58) and dementia DALYs (r = 0.54) with COVID-19 mortality. CONCLUSION: Health policymakers should clarify a targeted model of disease surveillance in order to reduce the dual burden of dementia and COVID-19
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