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A numerical investigation of entropy generation in laminar forced convection of gas flow over a recess including two inclined backward and forward facing steps in a horizontal duct under bleeding condition is presented. For calculation of entropy generation from the second law of thermodynamics in a forced convection flow, the velocity and temperature distributions are primary needed. For this purpose, the two-dimensional Cartesian coordinate system is used to solve the governing equations which are conservations of mass, momentum and energy. These equations are solved numerically using the computational fluid dynamic techniques to obtain the temperature and velocity fields, while the blocked region method is employed to simulate the inclined surface. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. The numerical results are presented graphically and the effects of bleeding coefficient and recess length as the main parameters on the distributions of entropy generation number and Bejan number are investigated. Also, the effect of Reynolds number and bleeding coefficient on total entropy generation which shows the amount of flow irreversibilities is presented for two recess length. The use of present results in the design process of such thermal system would help the system attain the high performance during exploitation. Comparison of numerical results with the available data published in open literature shows a good consistency. nema

The investigation of design parameters is very helpful for optimizing the capacity of an electrochemical cell, which can be done by both experimental and numerical methods. In this study, a lead-acid battery has been simulated numerically using the CFD commercial software package FLUENT. The governing equations, including conservation of charge in solid and liquid phases and conservation of species, are solved by developing several user defined functions (UDF). The effect of some basic parameters such as electrode porosity, discharge current density, and width of the electrodes and separator on the cell voltage behavior of a lead-acid battery is investigated. It has been shown that increasing the width and porosity of separator has both positive and negative effects on the performance parameters of battery. Furthermore, a thicker PbO 2 electrode has a more pronounced effect than a thicker Pb one.

The present work investigates the laminar forced convection flow of a radiating gas over an inclined backward facing step (BFS) in a horizontal duct. The momentum and energy equations are solved numerically by the CFD techniques to obtain the velocity and temperature fields. Since, the twodimensional Cartesian coordinate system is used to solve the governing equations; the flow over inclined surface is simulated by considering the blocked-off region in regular grid. Discretized forms of the governing equations in the (x,y) plane are obtained by the control volume method and solved using the SIMPLE algorithm. The fluid is treated as a gray, absorbing, emitting and scattering medium. Therefore, all of the convection, conduction and radiation heat transfer mechanisms take place simultaneously in the gas flow. For computation of the radiative term in the gas energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinates method (DOM) to find the radiative heat flux distribution inside the radiating medium. In the numerical results, effects of inclination angle, optical thickness, scattering albedo and the radiation-conduction parameter on the heat transfer behavior of the convection flow are investigated. This research work is a new one in which a combined convection-radiation thermal system with a complex flow geometry is simulate by efficient numerical techniques. nema

A numerical simulation procedure for studying deposition of aerosol particles in a laminar convection flow of radiating gas over a backward-facing step including the effect of thermal force is developed. In the gas flow, all of the heat transfer mechanisms consisting of conduction, convection and radiation take place simultaneously. Behavior of solid particles is studied numerically based on an Eulerian–Lagrangian method. Two dimensional Navier-Stokes and energy equations are solved using CFD techniques, while the radiating transfer equation (RTE) is solved by discrete ordinate method (DOM) for calculating radiative heat flux distribution. The objective of this research is to study the effect of Reynolds number variation and also radiation on thermophoretic deposition of particles. Numerical results show a decrease in deposition percent by increasing in Reynolds number and the radiation effect is negligible. The results are compared with the existing experimental and numerical data and good agreement is found.

As soil contamination with heavy metals is increasing and polyamines have roles in the growth of mycorrhiza and plants, it is important to study phytoremediation, growth, tolerance, and mycorrhization in Lallemantia iberica as a multi-purpose plant, by the application of putrescine along with mycorrhiza in Pb-contaminated soils. For this purpose, the study was performed in a factorial arrangement with Pb (0, 300, 600, and 900 mg Pb/kg soil), mycorrhiza (non-inoculation, Funneliformis mosseae (Fm), and Rhizophagus intraradices (Ri)), and putrescine (0, 0.5, and 1 mM) in a greenhouse. Results showed that antioxidant activities, plant Pb, and mycorrhizal features enhanced, while transfer factor (TF), biomass, and tolerance decreased under Pb levels. Mycorrhiza improved growth, greenness, defense, and tolerance and reduced TF, Pb, and H 2 O 2 content under Pb stress. Putrescine (0.5 mM) increased catalase activity, biomass, and colonization and reduced Pb content and TF under Pb levels. Combination of 0.5 mM putrescine with Fm increased shoot biomass (13%), peroxidase (17.2%), root P (7.5%), shoot tolerance (14.4%), colonization (5.1%), and hyphal width (5.5%) and decreased malondialdehyde (20.5%) and shoot Pb content (28.1%). Putrescine (1 mM) had negative effects on all traits in combination with Ri but not with Fm. Combination of putrescine and Fm showed more efficiency in decreasing Pb content in L. iberica and was effective in phytostabilization. It is generally concluded that 0.5 mM putrescine was the beneficial concentration in combination with mycorrhiza, Pb stress, and single use to improve plant performance, and Fm was a useful species for improving the growth and tolerance of L. iberica under Pb levels.

BackgroundAdmission neutrophil-lymphocyte ratio (NLR) is significantly correlated to clinical outcomes in acute ischemic stroke (AIS). We investigated follow-up NLR and temporal changes in NLR after endovascular thrombectomy (EVT) with respect to successful revascularization, clinical outcomes, symptomatic intracranial hemorrhage (sICH) and mortality.MethodsRetrospective analysis of EVT for anterior circulation emergent LVO was performed with both admission (NLR1) and 3–7 day follow-up NLR (NLR2) laboratory data. Patient demographics, National Institutes of Health Stroke Scale (NIHSS) presentations, reperfusion efficacy (modified Thrombolysis in Cerebral Infarction (mTICI) score), sICH, and clinical outcomes (modified Rankin Scale (mRS)) at 90 days were studied. Univariate analyses correlated NLR1, NLR2, and temporal change in NLR (NLR2-NLR1) with successful reperfusion (mTICI ≥2b), favorable outcomes (mRS ≤2), sICH, and mortality. Multivariable logistic regression model evaluated the independent effects of NLR2 on favorable outcomes.Results142 AIS patients with median NIHSS 17 underwent EVT within 24 hours, and met NLR laboratory inclusion criteria. Lower follow-up NLR2 and less temporal change in NLR over 3–7 days, but not admission NLR1, inversely correlated with successful reperfusion (p<0.05) and favorable clinical outcomes (p<0.001). Higher follow-up NLR2 and greater temporal change in NLR was significantly associated with sICH and mortality (p≤0.05). In multivariable logistic regression, lower follow-up NLR2 remained a predictor of favorable outcomes (OR 0.785, p=0.001), independent of age or successful reperfusion.ConclusionsFollow-up NLR is a readily available and modifiable biomarker that correlates with the degree of reperfusion after mechanical stroke thrombectomy. Lower follow-up NLR2 at 3–7 days is associated with successful reperfusion and an independent predictor of favorable clinical outcomes, with reduced risk for sICH and mortality.

Considering the scouring depth downstream of weirs is a challenging issue due to its effect on weir stability. The adaptive neuro-fuzzy inference systems (ANFIS) model integrated with optimization methods namely cultural algorithm, biogeography based optimization (BBO), invasive weed optimization (IWO) and teaching learning based optimization (TLBO) are proposed to predict the maximum depth of scouring based on the different input combinations. Several performance indices and graphical evaluators are employed to estimate the prediction accuracy in the training and testing phase. Results show that the ANFIS-IWO offers the highest prediction performance (RMSE = 0.148) compared to other models in the testing phase, while the ANFIS-BBO (RMSE = 0.411) provides the lowest accuracy. The findings obtained from the uncertainty analysis of prediction modeling indicate that the input variables variability has a higher impact on the predicted results than the structure of models. In general, the ANFIS-IWO can be used as a reliable and cost-effective method for predicting the scouring depth downstream of weirs.

Nitric oxide (NO) is recognized as an endogenous signaling molecule that plays an important role in the defence responses of medicinal plants to NaCl stress. In this study, we investigated the effects of sodium nitroprusside (SNP) as an NO donor at three concentrations (0, 100, and 200 µmol l −1 ) to alleviate the deleterious effects of salt stress (100 mM NaCl) on leaf gas exchange and biochemical characteristics of Silybum marianum L. seedlings. This study showed that salt stress significantly decreased relative water content (RWC), chlorophyll b content, endogenous NO concentration, maximum quantum yield (Fv/Fm), leaf gas exchange, stomatal size, K + /Na + ratio, and plant dry weight, and increased malondialdehyde (MDA) content, hydrogen peroxide (H 2 O 2 ) content, proline content, stomatal density, and enzyme activities. SNP treatment increased Fv/Fm, photosynthetic pigments, K + /Na + ratio, and dry weights of the shoots and roots of NaCl-exposed plants. The exogenous application of NO increased the proline content under salinity stress more than under stress conditions without SNP application, so that the proline content increased from 32 to 47 µmol g −1 . Application of 100 µM SNP also increased endogenous NO concentration (up to 43%) and consequently protected plants against salt stress-induced damage by improving enzyme activity and reducing the H 2 O 2 generation rate (up to 14%) and MDA content (up to 50%) compared to plants treated with NaCl alone. Foliar application of NO to salt-stressed plants increased root and shoot respiration rates from 20 and 12%, respectively, under salinity stress to 57% under the application of SNP and stress conditions, and decreased stomatal conductance by up to 70%, resulting in improved RWC. Increased internal NO generation in plants induced by 100 µM SNP application has the potential to mitigate salinity injury in Silybum marianum L. plants.

BackgroundHospital readmissions are costly and reflect negatively on care delivered.ObjectiveTo have a better understanding of unplanned readmissions after carotid revascularization, which might help to prevent them.MethodsThe Nationwide Readmissions Database was used to determine rates and reasons for unplanned readmission following carotid endarterectomy (CEA) and carotid artery stenting (CAS). Trends were assessed by annual percent change, modified Poisson regression was used to estimate risk ratios (RR) for readmission, and propensity scores were used to match cohorts.ResultsAnalysis yielded 522 040 asymptomatic and 55 485 symptomatic admissions for carotid revascularization between 2010 and 2015. Higher 30-day readmission rates were noted after CAS versus CEA in both symptomatic (9.1% vs 7.7%, p<0.001) and asymptomatic (6.8% vs 5.7%, p<0.001) patients. Readmission rates trended lower over time, significantly so for 90-day readmissions in symptomatic patients undergoing CEA. The most common cause for 30-day readmission was stroke in both symptomatic (5.5%) and asymptomatic (3.9%) patients. Factors associated with a higher risk of readmission included age over 80; male gender; Medicaid health insurance; and increases in severity of illness, mortality risk, and comorbidity indices. Analysis of matched cohorts showed that CAS had higher readmission than CEA (RR=1.14 (95% CI 1.06 to 1.22); p<0.001) only in asymptomatic patients. Adverse events during initial admission which predicted 30-day readmission included acute renal failure and acute respiratory failure in asymptomatic patients; hematoma and cardiac events were additional predictive adverse events in symptomatic patients.ConclusionsReadmission is not uncommon after carotid revascularization, occurs more often after CAS, and is predicted by baseline factors and by preventable adverse events at initial admission.

This study compares several advanced machine learning models to obtain the most accurate method for predicting the aeration efficiency (E 20 ) through the Parshall flume. The required dataset is obtained from the laboratory tests using different flumes fabricated in National Institute Technology Kurukshetra, India. Besides, the potential of K Nearest Neighbor (KNN), Random Forest Regression (RFR), and Decision Tree Regression (DTR) models are evaluated to predict the aeration efficiency. In this way, several input combinations (e.g. M1-M15) are provided using the laboratory parameters (e.g. W/L, S/L, Fr, and Re). Different predictive models are obtained based on those input combinations and machine learning models proposed in the present study. The predictive models are assessed based on several performance metrics and visual indicators. Results show that the KNN-M11 model ( ), which includes W/L, S/L, and Fr as predictive variables outperforms the other predictive models. Furthermore, an enhancement is observed in KNN model estimation accuracy compared to the previously developed empirical models. In general, the predictive model dominated in the present study provides adequate performance in predicting the aeration efficiency in the Parshall flume.