Structure Relationship between Self-imaginary and Meta-cognition Beliefs with Self-regulatory Learning in Pre-university Girl Students in Rasht City

AbstractIn this study the relationship between self-imaginary structure and meta-cognition beliefs with self-regulatory learning variable in pre-university girl students is investigated. 300 girl students have been selected with bunch random method from Rasht schools for this correlative study. Some devices like schooling self-imaginary questionnaire, meta-cognition questionnaire and self-regulatory learning questionnaire are used to collect the students Data. Data are analyzed with Pearson correlation, regression and one-way ANOVA methods. The analysis shows negative and significant correlation between meta-cognition beliefs variable and self-regulatory learning. This means that reduction of meta-cognition beliefs increases the students learning ability. Also, it is concluded that there is considerable positive correlation between self-imaginary and self-regulatory learning and significant negative association between self-imaginary variable and meta-cognition beliefs. Furthermore, the regression and ANOVA analysis show that self-imaginary and meta-cognition beliefs which are independent variables are not suitable anticipants for self-regulatory learning. Results show that meta-cognition beliefs lead to objective thinking and psychological traumas and play inhibitory role in self-regulatory process. Indeed, people with inner control and positive self-imaginary, have better control on the learning facts and their results. These people have more effective role in the self-regulatory process

Particles in turbulent separated flow over a bump: effect of the Stokes number and lift force

Particle-laden turbulent flow that separates due to a bump inside a channel is simulated to analyse the effects of the Stokes number and the lift force on the particle spatial distribution. The fluid friction Reynolds number is approximately 900 over the bump, the highest achieved for similar computational domains. A range of particle Stokes numbers are considered, each simulated with and without the lift force in the particle dynamic equation. When the lift force is included a significant difference in the particle concentration, in the order of thousands, is observed in comparison with cases where the lift force is omitted. The greatest deviation is in regions of high vorticity, particularly at the walls and in the shear layer but results show that the concentration also changes in the bulk of the flow away from the walls. The particle behaviour changes drastically when the Stokes number is varied. As the Stokes number increases, particles bypass the recirculating region that is formed after the bump and their redistribution is mostly affected by the strong shear layer. Particles segregate at the walls and particularly accumulate in secondary recirculating regions behind the bump. At higher Stokes numbers, the particles create reflection layers of high concentration due to their inertia as they are diverted by the bump. The fluid flow is less influential and this enables the particles to enter the recirculating region by rebounding off walls and create a focus of high particle concentration.Comment: 8 pages, 9 figures, submitted to Physics of Fluid

Smoking Knowledge, Attitude and Behavior of Child Labor Who Live in Tehran during 2013-2014

Background: Children and adolescent smoking is one of the most important health problems in the world. There is a major concern that child labor may generate a pseudo maturity syndrome, including smoking.The current survey focus on smoking behavior, knowledge and attitude of child labor are working in Tehran.Materials and Methods: The study adopted a cross-sectional design, based on a primary pilot descriptive cross sectional study, using GYTS self-administered questionnaire. 816 child labor, which were student of work labor schools or worked as child labor on Tehran parks and crossing roads, were randomly selected using multi stage cluster sampling. DATA analyzed using SPSS v.22 (IBM statistic) software and chi square test to compare the frequency of variables in different groups.Results: 50.6% of our participants were boy and child laboring age varied from 11 to 17 years old. 18.6% of child labor had smoking experience (Confident Interval 95%=17.3-20.1). 9.8% of them were current smoker (CI 95%=8.6-10.9) and 1.2% were current regular smoker (CI 95%=0.9-2.1). Child labor smoking hazard knowledge was evaluated by considering the minimum and maximum score of 10 to 30. Results demonstrated that the mean score of knowledge, attitude and behavior were 17.1±6.2, 36.5±16.1 (range 15-45) and 46.1±3.0 (range 25-75), respectively.Conclusion: Considering to our findings, planning tobacco control program for these specific groups is required, aiming at preventing cigarette smoking by increasing the knowledge and correcting their attitude

Particles in turbulent separated flow over a bump : effect of the Stokes number and lift force

Accepted manuscript. Formal publication: Physics of Fluids 31, 103305 (2019); https://doi.org/10.1063/1.5119103Particle-laden turbulent flow that separates due to a bump inside a channel is simulated to analyze the effects of the Stokes number and the lift force on the particle spatial distribution. The fluid friction Reynolds number is approximately 900 over the bump, the highest achieved for similar computational domains. The presence of the bump creates a complex background flow with a recirculating region and a strong shear layer. A range of particle Stokes numbers are considered, each simulated with and without the lift force in the particle dynamic equation. The effect of the lift force on the particle concentration is dominant in regions of high spanwise vorticity, particularly at the walls and in the shear layer. The concentration change is of the order of thousands when compared to cases where the lift force is omitted. At a low Stokes number, the particles segregate at both top and bottom walls and are present in the recirculating region. As the Stokes number increases, particles bypass the recirculating region and their redistribution is mostly affected by the strong shear layer. Particles segregate at the walls and particularly accumulate in secondary recirculating regions behind the bump. At higher Stokes numbers, the particles create reflection layers of high concentration due to their inertia as they are diverted by the bump. The fluid flow is less influential, and this enables the particles to enter the recirculating region by rebounding off walls and create a focused spot of high particle concentration.peer-reviewe

Fabrication and characterization of polycaprolactone fumarate/gelatin-based nanocomposite incorporated with silicon and magnesium co-doped fluorapatite nanoparticles using electrospinning method

The aim of this study was to fabricate and characterize biodegradable polycaprolactone fumarate(PCLF)/gelatin-based nanocomposite incorporated with the 0, 5 and 10 wt% silicon and magnesium co-doped fluorapatite nanoparticles (Si -Mg-FA) membranes using electrospinning process for guided bone regeneration (GBR) and guided tissue regeneration (GTR) applications. Results demonstrated the formation of randomly-oriented and defect-free fibers with various fiber sizes depending on the Si -Mg-FA content. Moreover, incorporation of 5 wt% Si -Mg-FA significantly improved the mechanical strength (1.5times) compared to the mechanical strength of PCLF/gelatin membrane and nanocomposite with 10 wt% nanoparticles. There was no clear difference between degradation rate of PCLF/gelatin and PCLF/gelatin with 5 wt% nanoparticles at 7, 14 and 28 days of immersion in phosphate buffer saline while 10 wt% nanoparticles significantly increased biodegradation of PCLF/gelatin, and no cytotoxic effect of membranes was seen. Finally, scanning electron microscopy (SEM) micrographs of fibroblast cells cultured on the samples demonstrated that the cells were completely attached and spread on the surface of nanocomposites. In summary, PCLF/gelatin membranes consisting of 5 wt% Si -Mg-FA nanoparticles could provide appropriate mechanical and biological properties and fairly good degradation rate, making it appropriate for GTR/GBR applications

Effect of Active and Passive Exposure to Cigarette Smoke on Lipid Profile of Children and Adolescents; A Systematic Review and Meta-Analysis

Background: The present systematic review and meta-analysis is designed in order to assess the association between passive and active smoking and lipid profile of children and adolescents. Materials and Methods:  An extensive search was done in databases of Medline, EMBASE, Web of Science, Scopus and CINAHL until October 2017. Two independent researchers screened articles and in the next step, full texts of probably relevant articles were read and summarized. At the end, results of mentioned studies were pooled and a standardized mean difference (SMD) with 95% confidence interval (95% CI) was reported. Results: Data from 17 studies (containing 41619 children and adolescents; age group between 4 and 18 years old; 51.72% boys) were entered. Comparing serum level of high density lipoprotein (HDL) in two groups of exposed and non-exposed to cigarette smoking showed that active exposure (SMD= -0.40, 95% CI: -0.59 to -0.21) and passive exposure to cigarette smoke (SMD= -0.18, 95% CI: -0.30 to -0.06) decreases the serum level of mentioned lipoprotein. Additionally, active exposure to cigarette smoke (SMD=0.16, 95% CI: 0.06 to 0.27) causes a modest increase in serum level of triglyceride. However, cigarette smoke exposure does not have any effect on the level of total cholesterol and low density lipoprotein (LDL). Conclusion: The present meta-analysis showed that exposure to cigarette smoke leads to a significant decrease in the level of HDL and triglyceride but, it does not have any effect of the level of total cholesterol and LDL in children and adolescents

Optimisation aéroélastique des plaques composites à l'aide d'approches déterministes et stochastiques

With the growing popularity of composite materials in aeronautics, study of the influence of their anisotropy on the aeroelastic behaviour of various structures is imminent. This type of study is referred to as aeroelastic tailoring which implies the variation of the composite structure properties in order to obtain the desired aeroelastic response. While there has been some work done in this field, the robustness of the methods used in order to deal with the anisotropy of the composite materials has not yet been at a satisfying level. The first focus of this work is on reformulation of the aeroelastic optimisation problem, in order to achieve a faster convergence with more reliable control over the elastic properties of the final structure. For this purpose a 2-level optimisation method is presented during which a parametric formulation is employed for optimisation of the aeroelastic behaviour. The formulation is based on polar parameters which can describe the anisotropic behaviour of a given structure. The first level of the optimisation is conducted by the Genetic Algorithm. The second level study is then considered which is associated to the retrieval of a stacking sequence with 16 plies in this work that has identical properties as the optimal polar parameters. Next, the tow-steered laminates with variable stiffnesses have been studied. This type of material can increase the rigidity of the structure and positively impact various static and dynamic responses of the latter. Using the polar parameters, the variation of the rigidity along the structure has been modelled and its aeroelastic behaviour has been optimised between 2-4%. Finally, the stochastic response of the optimal case obtained during the deterministic optimisation process has been considered. The parametric uncertainties during the manufacturing of composite laminates can impact the aeroelastic response of the system. The parametric uncertainties have been included in the optimisation process resulting in a reliability-based design optimisation. The discontinuities present on the aeroelastic response surface render the approximation made by the surrogate model less accurate. The use of a continuous function called the stability margin is the solution to this discontinuity problem which helps with the computational time as well.Avec la popularité croissante des matériaux composites en aéronautique, l'étude de l'influence de leur anisotropie sur le comportement aéroélastique de diverses structures est imminente. Ce type d'étude est appelé adaptation aéroélastique et implique la variation des propriétés de la structure composite afin d'obtenir la réponse aéroélastique souhaitée. Bien que certains travaux aient été réalisés dans ce domaine, la robustesse des méthodes utilisées pour traiter l'anisotropie des matériaux composites n'a pas encore atteint un niveau satisfaisant. Le premier objectif de ce travail est de reformuler le problème d'optimisation aéroélastique, afin d'obtenir une convergence plus rapide et un contrôle plus fiable des propriétés élastiques de la structure finale. À cette fin, une méthode d'optimisation à deux niveaux est présentée, au cours de laquelle une formulation paramétrique est utilisée pour l'optimisation du comportement aéroélastique. La formulation est basée sur des paramètres polaires qui peuvent décrire le comportement anisotrope d'une structure donnée. Le premier niveau d'optimisation est conduit par l'Algorithme Génétique. L'étude de second niveau est ensuite envisagée, associée à l'obtention d'une séquence d'empilement de 16 plis dans ce travail qui présente des propriétés identiques aux paramètres polaires optimaux. Ensuite, les stratifiés de type tow-steered avec des rigidités variables ont été étudiés. Ce type de matériau peut augmenter la rigidité de la structure et avoir un impact positif sur diverses réponses statiques et dynamiques de cette dernière. En utilisant les paramètres polaires, la variation de la rigidité le long de la structure a été modélisée et son comportement aéroélastique a été optimisé entre 2 et 4 %. Enfin, la réponse stochastique du cas optimal obtenu au cours du processus d'optimisation déterministe a été considérée. Les incertitudes paramétriques lors de la fabrication des laminés composites peuvent avoir un impact sur la réponse aéroélastique du système. Les incertitudes paramétriques ont été incluses dans le processus d'optimisation, ce qui a donné lieu à une optimisation de la conception basée sur la fiabilité. Les discontinuités présentes sur la surface de réponse aéroélastique rendent l'approximation faite par le modèle de substitution moins précise. L'utilisation d'une fonction continue appelée marge de stabilité est la solution à ce problème de discontinuité et permet également de réduire le temps de calcul

Optimisation aéroélastique des plaques composites à l'aide d'approches déterministes et stochastiques

Avec la popularité croissante des matériaux composites en aéronautique, l'étude de l'influence de leur anisotropie sur le comportement aéroélastique de diverses structures est imminente. Ce type d'étude est appelé adaptation aéroélastique et implique la variation des propriétés de la structure composite afin d'obtenir la réponse aéroélastique souhaitée. Bien que certains travaux aient été réalisés dans ce domaine, la robustesse des méthodes utilisées pour traiter l'anisotropie des matériaux composites n'a pas encore atteint un niveau satisfaisant. Le premier objectif de ce travail est de reformuler le problème d'optimisation aéroélastique, afin d'obtenir une convergence plus rapide et un contrôle plus fiable des propriétés élastiques de la structure finale. À cette fin, une méthode d'optimisation à deux niveaux est présentée, au cours de laquelle une formulation paramétrique est utilisée pour l'optimisation du comportement aéroélastique. La formulation est basée sur des paramètres polaires qui peuvent décrire le comportement anisotrope d'une structure donnée. Le premier niveau d'optimisation est conduit par l'Algorithme Génétique. L'étude de second niveau est ensuite envisagée, associée à l'obtention d'une séquence d'empilement de 16 plis dans ce travail qui présente des propriétés identiques aux paramètres polaires optimaux. Ensuite, les stratifiés de type tow-steered avec des rigidités variables ont été étudiés. Ce type de matériau peut augmenter la rigidité de la structure et avoir un impact positif sur diverses réponses statiques et dynamiques de cette dernière. En utilisant les paramètres polaires, la variation de la rigidité le long de la structure a été modélisée et son comportement aéroélastique a été optimisé entre 2 et 4 %. Enfin, la réponse stochastique du cas optimal obtenu au cours du processus d'optimisation déterministe a été considérée. Les incertitudes paramétriques lors de la fabrication des laminés composites peuvent avoir un impact sur la réponse aéroélastique du système. Les incertitudes paramétriques ont été incluses dans le processus d'optimisation, ce qui a donné lieu à une optimisation de la conception basée sur la fiabilité. Les discontinuités présentes sur la surface de réponse aéroélastique rendent l'approximation faite par le modèle de substitution moins précise. L'utilisation d'une fonction continue appelée marge de stabilité est la solution à ce problème de discontinuité et permet également de réduire le temps de calcul.With the growing popularity of composite materials in aeronautics, study of the influence of their anisotropy on the aeroelastic behaviour of various structures is imminent. This type of study is referred to as aeroelastic tailoring which implies the variation of the composite structure properties in order to obtain the desired aeroelastic response. While there has been some work done in this field, the robustness of the methods used in order to deal with the anisotropy of the composite materials has not yet been at a satisfying level. The first focus of this work is on reformulation of the aeroelastic optimisation problem, in order to achieve a faster convergence with more reliable control over the elastic properties of the final structure. For this purpose a 2-level optimisation method is presented during which a parametric formulation is employed for optimisation of the aeroelastic behaviour. The formulation is based on polar parameters which can describe the anisotropic behaviour of a given structure. The first level of the optimisation is conducted by the Genetic Algorithm. The second level study is then considered which is associated to the retrieval of a stacking sequence with 16 plies in this work that has identical properties as the optimal polar parameters. Next, the tow-steered laminates with variable stiffnesses have been studied. This type of material can increase the rigidity of the structure and positively impact various static and dynamic responses of the latter. Using the polar parameters, the variation of the rigidity along the structure has been modelled and its aeroelastic behaviour has been optimised between 2-4%. Finally, the stochastic response of the optimal case obtained during the deterministic optimisation process has been considered. The parametric uncertainties during the manufacturing of composite laminates can impact the aeroelastic response of the system. The parametric uncertainties have been included in the optimisation process resulting in a reliability-based design optimisation. The discontinuities present on the aeroelastic response surface render the approximation made by the surrogate model less accurate. The use of a continuous function called the stability margin is the solution to this discontinuity problem which helps with the computational time as well