230 research outputs found
Classification of Seismic Vulnerability Based on Machine Learning Techniques for RC Frames
Seismic vulnerability means the inability of historical and monumental buildings to withstand the effects of seismic forces. This article presents a classification model to specify the damage state of the Reinforced Concrete (RC) frames based on a collection of datasets from the damaged buildings in Bingol earthquake of Turkey for use in the learning process of the algorithm. The proposed model uses two classifiers including the redundancy and also the construction quality of the buildings to estimate the class of damage from four categories including none, light, moderate and severe. The available database of the considered earthquake includes the information of 27 damaged RC buildings which are published in the literature. The model provided a simple structure for engineers to predict the class without complex calculations in which it needs a few steps to determine the class of damage for RC frames. The results show that the presented model can estimate the class of each input vector with an acceptable error
Finite Element Model to Investigate the Dynamic Instability of a Rectangular Plate Subjected to Supersonic Airflow
RÉSUMÉ Dans cette thèse, une méthode numérique est présentée pour étudier le comportement dynamique d'une plaque rectangulaire isotrope soumise à des charges aérodynamiques induites par un flux d'air supersonique parallèle. Un modèle d'éléments finis, basé sur des fonctions de déplacement polynomiales bidimensionnelles et sur la théorie des pistons linéaires, est utilisé pour étudier le comportement dynamique de la plaque solide couplée avec charges aérodynamiques. L'approche développée est capable de modéliser des plaques plates et des coques peu profondes dans lesquelles le couplage fluide-structure à l'interface est appliqué de manière synchrone sur la base d'une méthode monolithique. La raideur élémentaire et l'amortissement obtenus à partir de la charge aérodynamique sont couplés avec à ceux obtenus à partir du modèle structurel et ils sont calculés par intégration analytique. En assemblant les matrices élémentaires, nous obtenons les matrices globales de masse, d'amortissement et de raideur de notre plaque puis nous pouvons écrire les équations dynamiques régissant notre problème. Les valeurs propres du système sont calculées selon la méthode réduite. La pression aérodynamique non dimensionnelle critique du flux d'air induisant le flottement de la structure est déterminée pour diverses conditions aux limites et géométries. Les résultats obtenus sont comparés aux travaux de recherche publiés et un très bon accord a été souligné.---------- ABSTRACT In this thesis, a numerical method is presented to study the dynamic behaviour of an isotropic rectangular plate subjected to aerodynamic loads induced by parallel supersonic airflow. A finite element model, based on bi-dimensional polynomial displacement functions and linear Piston theory, is used to study the dynamic behaviour of the solid plate coupled with aerodynamic loads. The developed approach is capable to model flat plates and shallow shells in which the fluid- structure coupling at the interface is applied synchronously based on a monolithic method. The stiffness and damping obtained from aerodynamic load are coupled with those obtained from structural model and they are calculated using analytical integration. By assembling the matrices, we obtain the global mass, damping and stiffness matrices for our plate and then we can write the dynamic equations governing our problem. The eigenvalues of the system are calculated using reduced method. The critical non-dimensional aerodynamic pressure of the airflow inducing flutter of the structure is determined for various boundary conditions and geometries. The obtained results are compared with the published research works and a very good agreement is obtained
Moisture content on some engineering properties of celery (Apium Graveolens L) seeds
The study was conducted to investigate some physical properties of celery seed at various moisture levels. The average length, width, thickness and 1000-seeds mass were 0.571, 0.429, 0.295 mm and 0.792 g, respectively, at moisture content of 5.24% (d.b). Length, width and thickness distributions of the seeds were modeled using Generalized Extreme Value, lognormal and Weibull distributions. Results showed that to model length of the seeds, lognormal distribution had the best performance while to model the width of the seeds Weibull distribution had the best performance. True density has increase from 892.02 to 931.42 kg/m3 when the moisture content increased from 5.24% to 20.25% (d.b). The angle of static friction increased from 28.45 to 39.66°, 25.15 to 34.84°, 19.57 to 27.07° and 16.72 to 19.720° for plywood, rubber, iron and galvanized metal, respectively, as the moisture content increases from 5.24% to 20.25% (d.b). The pouring angle of repose increased from 34.70 to 39.12°, 33.37 to 36.37°, 30.59 to 33.33° and 27.16 to 29.45° for plywood, rubber, iron and galvanized metal , respectively, as the moisture content increases from 5.24% to 20.25% (d.b). The Hele-Shaw angle of repose increased from 32.65 to 35.25°, 30.35 to 32.77°, 27.81 to 30.03° and 24.72 to 26.61° for plywood, rubber, iron and galvanized metal , respectively, as the moisture content increases from 5.24% to 20.25% (d.b)
Bis(μ-pyridinium-2-carboxylato-κ2 O:O′)bis[triaqua(sulfato-κO)manganese(II)]
The asymmetric unit of the title compound, [Mn2(SO4)2(C6H5NO2)2(H2O)6], comprises half of a centrosymmetric dimer. The MnII atom is coordinated by two O atoms of the monodentate carboxylate ligand, an O atom of the sulfate anion in axial position and three water molecules in a distorted octahedral geometry. In the crystal, molecules are connected through N—H⋯O and O—H⋯O hydrogen bonds, forming a three-dimensional network. The crystal structure is further stabilized by intermolecular π–π interactions [centroid–centroid distance = 3.842 (2) Å]
A New Formula for Confirmation of Proper Endotracheal Tube Placement with Ultrasonography
Background Endotracheal intubation is an important procedure in critical care and emergency medicine settings. Optimal depth of the tube placement has been a serious concern because of several complications associated with its malposition. Objective: The aim of the current study was to find a new formula to estimate the proper endotracheal tube depth when using ultrasonography or lighted stylet device in order to increase the accuracy of determining Endotracheal tube (ETT) depth and decrease the side effects of ETT misplacement. Method: Patients older than 18 years of age admitted to Imam emergency department who needed tracheal intubation were included. Tube’s length at the angle of the mouth while the tube passed the suprasternal notch, ETT depth after insertion and the distance from ETT’s tip to carina were recorded. Ultrasonography and portable chest x-ray were used as tools for measuring these lengths. Results: A total number of 91 patients including 55 men and 36 women were eligible for inclusion in the study. Not placing the tube at proper depth was considered as failure of intubation. This failure rate was 9.9% in the standard method which would have been 1.1% if our proposed formula was used. Conclusion: The findings of this study suggest that the use of this new formula may help in predicting the proper intubation tube placement. Further studies are warranted to confirm these findings
Comparative Investigation of Health Quality of Air in Tehran, Isfahan and Shiraz Metropolises in 2011-2012
Background and Aims: Air pollution causes wide spectrum acute and chronic effects of health from slight physiological disorders to death from cardiovascular and respiratory diseases. In order to set the control programs, air pollution monitoring and determination of air quality are necessary. The objective of this study was to compare health quality of air in Tehran, Isfahan and Shiraz cities in 2011- 2012.Materials and Methods: This Study was a descriptive–analytic study. The moment concentrations of Tehran,Isfahan and Shiraz air pollutants were gathered through referring to the environmental protection agency.Then, Air Quality Index (AQI) was calculated based on the criteria pollutants’ levels (CO, NO2, SO2, PM10,PM2.5 and O3) for three cities through linear interpolation and was classified into describing classes accordingto tables of National Ambient Air Quality Standards. Data analysis was performed with Excel and SPSS software using One-Way ANOVA test.Results: The results showed that the AQI in Tehran, Isfahan and Shiraz was higher than Iran’s environmental protection agency standards (AQI>100) in 341, 323 and 85 days, respectively. Furthermore, particulate matter (PM10) has been the critical pollutant in three cities for most days of the year. One-Way ANOVA test between AQI mean of the three cities showed a significant difference.Conclusion: The air quality of the three cities was unhealthy in 2011-2012 and the situation of Tehran andIsfahan air, however, was in the “bad situation”.Key words: Air pollutants, Air quality index, Pollution standard index, Responsible pollutan
Photocatalytic Removal of Methylbenzene Vapors by MnO2/Al2O3/Fe2O3 Nano composite
Methyl benzene, which has carcinogenic effects, is a volatile organic compound that is widely used in various industries. Nano composites of Mno2/Al203/Fe203, which is a new photocatalyst, have not been applied to remove contaminants from air streams. Therefore, the aim of the present study was to investigate the photocatalytic removal of ethyl benzene by using this nano composite activated by visible light. Morphological characteristics of the synthesized Nano composite in a sol-gel method are determined through XRD, FTIR, and SEM. Through the photocatalyst process and by the use of visible light radiation, the synthesized Nano composite is used to degrade ethyl benzene in the gas phase. In order to estimate the main effects and interaction ones and to optimize the experiment numbers, the response surface method was used. Operational parameters investigated in the study are the initial concentration of contaminants, relative humidity, and the residence time, which were considered in three levels; further, the experiments were designed by Design Expert version 9 software. The results show the Nano composite particle sizes were less than 82 nanometers. The findings also indicate that relative humidity and residence time were effective parameters in removal efficiency of ethyl benzene. This Nano composite, at the optimal conditions, was capable of removing 98.72% of the pollutants, with an initial content of 300 ppm. MnO2/Al2O3/Fe2O3 Nano composite is a suitable catalyst to remove ethyl benzene from air streams. Among the features of the Nano composite are reaction at room temperature and lower production dangerous byproducts, which are the main advantages of this Nano composite as compared with other nano composites
Photocatalytic Removal of Methylbenzene Vapors by MnO2/Al2O3/Fe2O3 Nano composite
Methyl benzene, which has carcinogenic effects, is a volatile organic compound that is widely used in various industries. Nano composites of Mno2/Al203/Fe203, which is a new photocatalyst, have not been applied to remove contaminants from air streams. Therefore, the aim of the present study was to investigate the photocatalytic removal of ethyl benzene by using this nano composite activated by visible light. Morphological characteristics of the synthesized Nano composite in a sol-gel method are determined through XRD, FTIR, and SEM. Through the photocatalyst process and by the use of visible light radiation, the synthesized Nano composite is used to degrade ethyl benzene in the gas phase. In order to estimate the main effects and interaction ones and to optimize the experiment numbers, the response surface method was used. Operational parameters investigated in the study are the initial concentration of contaminants, relative humidity, and the residence time, which were considered in three levels; further, the experiments were designed by Design Expert version 9 software. The results show the Nano composite particle sizes were less than 82 nanometers. The findings also indicate that relative humidity and residence time were effective parameters in removal efficiency of ethyl benzene. This Nano composite, at the optimal conditions, was capable of removing 98.72% of the pollutants, with an initial content of 300 ppm. MnO2/Al2O3/Fe2O3 Nano composite is a suitable catalyst to remove ethyl benzene from air streams. Among the features of the Nano composite are reaction at room temperature and lower production dangerous byproducts, which are the main advantages of this Nano composite as compared with other nano composites
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