On the hydrodynamics and heat convection of an impinging external flow upon a cylinder with transpiration and embedded in a porous medium

This paper extends the existing studies of heat convection by an external flow impinging upon a flat porous insert to that on a circular cylinder inside a porous medium. The surface of the cylinder is subject to constant temperature and can include uniform or non-uniform transpiration. These cylindrical configurations are introduced in the analyses of stagnation point flows in porous media for the first time. The equations governing steady transport of momentum and thermal energy in porous media are reduced to simpler nonlinear differential equations and subsequently solved numerically. This reveals the dimensionless velocity and temperature fields of the stagnation-point flow, as well as the Nusselt number and shear stress on the surface of the cylinder. The results show that transpiration on the surface of the cylinder and Reynolds number of the external flow dominate the fluid dynamics and heat transfer problems. In particular, non-uniform transpiration is shown to significantly affect the thermal and hydrodynamic responses of the system in the circumferential direction. However, the permeability and porosity of the porous medium are found to have relatively smaller influences

Transient analysis of the interactions between a heat transferring, radial stagnation flow and a rotating cylinder-magnetohydrodynamic and non-uniform transpiration effects

This paper aims at providing further understanding on the fluid flow and heat transfer processes in unsteady rotating systems with mass transpiration. Such systems can be found in chemical separators, hydraulic systems, and printing devices. To this end, an unsteady viscous flow in the vicinity of an unaxisymmetric stagnation-point on a rotating cylinder is examined. The nonuniform transpiration and a transverse magnetic field are further considered. The angular speed of the cylinder and the thermal boundary conditions are expressed by time-dependent functions. A reduction of the Navier–Stokes and energy equations is obtained through using appropriate similarity transformations. The semisimilar solution of the Navier–Stokes equations and energy equation are developed numerically using an implicit finite difference scheme. Pertinent parameters including the Reynolds number and magnetic parameter and transpiration function are subsequently varied systematically. It is shown that the transpiration function can significantly affect the thermal and hydrodynamic behaviors of the system. In keeping with the findings in other areas of magnetohydrodynamics (MHD), the results show that the applied magnetic field has modest effects on the Nusselt number. However, it is demonstrated that the magnetic effects can significantly increase the imposed shear stress on the surface of the rotating cylinder

Continuous K-g-fusion frames in Hilbert spaces

This paper aims at introducing the concept of c-K-g-fusion frames, which are generalizations of K-g-fusion frames, proving some new results on c-K-g-fusion frames in Hilbert spaces, defining duality of c-K-g-fusion frames and characterizing the kinds of the duals, and discussing the perturbation of c-K-g-fusion frames.Publisher's Versio

Optimization of wall components for encapsulation of Nigella sativa seed oil by freeze-drying

The aim of the present study was to determine the proper concentrations of whey protein isolate (WPI), Arabic gum (AG), and Zedo gum (ZG) for the encapsulation of Nigella sativa seed oil (NSO). WPI, AG, and ZG were used as wall materials for the encapsulation of NSO by mixture design and then the optimum sample with minimum Z-average, PDI, and a* and maximum zeta potential, conductivity, encapsulation efficiency, and b* was selected for examining FT-IR and SEM. The findings demonstrated that lower particle size and particle dispersion index were obtained at higher amounts of AG and WPI with the least a*. Desirability function results indicate that the mixture of 39.05% WPI, 16.758% AG, and 4.192% ZG led to the production of the optimum sample. Microencapsulation of Nigella sativa seed oil using the optimum wall composition was recognized to be useful to preserve bioactive compounds and provide flavor stability, enabling the use of microcapsules in food formulations

Corporate governance and intellectual capital

The purpose of this paper is to examine the association between corporate governance and Intellectual capital in the pharmaceutical companies accepted in Tehran Stock Exchange over the period 2004-2009 using a regression based model. The study investigates the impacts of three some independent variables of the corporate governance (i.e. the number of board members, the relative extent of nonexecutive to executive directors, the auditing committee). The results suggest that corporate governance had no special effect on intellectual capital in the pharmaceutical companies. Furthermore among corporate governance's variables, the first one (i.e. board size) had negative impact on firms' intellectual capital and the second and the third variables had no effects on intellectual capital

Effect of intra-organizational factors on research

      Along with other areas in our country, the research in medical sciences is a necessity for the maintenance and improvement of community health. The objectives of this study were to determine the intra-organizational factors of conducting research in Tabriz University of Medical Sciences. The matrix of the study included entire academic members and research staff of the university where 121 of them were selected randomly for a descriptive cross sectional study. A questionnaire was designed to collect data using Likert Spectrum. The major difficulty was the lack of sufficient free time. Significant differences were seen in respect with the access to facilities and conducting research, assessing expected benefits of conducting research, level of research awareness among academic members with and without research project. Differences in respect with motivation force, collaboration, job satisfaction and expected benefits from conducting research were shown to be not significant. As stated by academic members, their problems involved with conducting research projects provides lesser role of intra-organizational factors compared to that of personal factors. In other words, the most major problems in not doing research are the lack of sufficient time and proper skills in research method and innovation in looking for problems to be solved.

Determinants of hookah smoking among men in the coffee houses : an application of socio-ecological approach

Background: Tobacco smoking is the second leading cause of death and is closely linked to fatal diseases. Hookah Smoking (HS) is a traditional way to smoke tobacco, especially in the Eastern Mediterranean region that is constantly rising around the world. This study aimed to evaluate the different levels of personal, interpersonal and social HS in Iranian urban men and determine the most important predictors of the levels through applying the socio-ecological approach (SEA). Methods: This study was conducted in the coffee houses of Hashtrud and Qarah Aghaj counties in East Azerbaijan, Iran. Data collection was conducted from the entire coffee house (n = 18) from April to June 2017. Systematic sampling was employed to recruit 266 men in the coffee house. A valid and reliable instrument was used to investigate the frequency of HS and its determinants based on SEA. The SEA consists of three levels: personal (age, education, employment, income, and perceived severity and sensitivity), interpersonal (perceived reward), and social level (social support) intended to assess HS determinants. Hierarchical regression was used to determine the predictive value of SEA levels and frequency of HS. Results: The mean age of daily hookah smokers (once per day and more than once per day) were (26.8) significantly lower than those (30.4) smokes weekly (once a week or more than once a week). The hierarchical logistic regression model showed that in the first step individual variables significantly predict 25.1% HS. In the second and third level interpersonal and social levels of SEA explained HS 30.1 and 30.8%, respectively. Conclusion: This study found that age, income, education, and perceived reward were all important factors influencing HS among men youth. Application of SEA to determine the factors associated with HS could contribute in the development of a holistic prevention program

Efecto inhibidor de Lactobacillus aislado de la cavidad oral contra patógenos bacterianos y su efecto en la promoción de la salud

Aims: To determine the inhibitory effect of oral Lactobacillus against bacterial pathogens and investigate correlation between presence of Lactobacillus strains and health promotion. Method: One hundred saliva samples were collected from oral cavity of domestic dairy consumers and were investigated for the isolation and identification of Lactobacillus strain by conventional culture and sequencing of 16SrRNA. Furthermore, well diffusion assay was performed to determination of antibacterial activity of Lactobacillus strains against bacterial pathogens including Salmonella typhimurium, Klebsiella pneumoniae, Shigella sonnei, Shigella dysenteriae, Enterococcus faecalis and Enterococcus faecium. Finally, association between health condition and isolation of Lactobacillus were investigated and obtained data using questionary form were analysed by chi-square test. Results: Thirty Lactobacillus strains recovered from 100 hundred saliva samples. The most common isolated strain was L. gasseri (n=18) and followed by L. vaginalis (n=3) and L. salivarius (n=3). All Lactobacillus strains demonstrated antibacterial activity against at least one of the investigated pathogens. However, the strongest results were obtained by L. vaginalis against K. pneumonia. The correlation between the presence of thirty Lactobacillus strains and health promotion not found. However, only L. gasseri species has significant positive impact on health in their hosts (P < 0.05). Conclusion: Only some Lactobacillus species have a positive impact on health promotion. Despite of weak activity against the investigated pathogens, L. gasseri has a positive impact on the mental problem (intense anger and depression) of their hosts.Objetivos: Determinar el efecto inhibidor del Lactobacillus aislado de la cavidad oral contra patógenos bacterianos e investigar la correlación entre la presencia de cepas de Lactobacillus y la promoción de la salud. Método: se recolectaron cien muestras de saliva de la cavidad oral de consumidores de productos lácteos y se investigó el aislamiento e identificación de la cepa de Lactobacillus mediante cultivo convencional y secuenciación de 16SrRNA. Además, se realizó un ensayo de difusión en pocillos para determinar la actividad antibacteriana de las cepas de Lactobacillus contra patógenos bacterianos que incluyen Salmonella typhimurium, Klebsiella pneumoniae, Shigella sonnei, Shigella dysenteriae, Enterococcus faecalis y Enterococcus faecium. Finalmente, se investigó la asociación entre el estado de salud y el aislamiento de Lactobacillus y se obtuvieron los datos utilizando el cuestionario mediante la prueba de chi-cuadrado. Resultados: Se aislaron treinta cepas de Lactobacillus de 100 muestras de saliva. La cepa aislada más común fue L. gasseri (n = 18), seguida por L. vaginalis (n = 3) y L. salivarius (n = 3). Todas las cepas de Lactobacillus demostraron actividad antibacteriana contra al menos uno de los patógenos investigados. Sin embargo, los resultados más fuertes fueron obtenidos por L. vaginalis contra K. pneumonia. No se encontraron correlación entre la presencia de algunas de las treinta cepas de Lactobacillus y la promoción de la salud. Sin embargo, solo la especie L. gasseri tuvo un impacto positivo significativo en la salud de sus hospedadores (P <0,05). Conclusión: solo algunas especies de Lactobacillus tienen un impacto positivo en la promoción de la salud. A pesar de la actividad débil contra los patógenos investigados, L. gasseri tiene un impacto positivo en el problema mental (ira intensa y depresión) de sus huéspedes