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

Developing Talent from a Supply-Demand Perspective: An Optimization Model for Managers

While executives emphasize that human resources (HR) are a firm's biggest asset, the level of research attention devoted to planning talent pipelines for complex global organizational environments does not reflect this emphasis. Numerous challenges exist in establishing human resource management strategies aligned with strategic operations planning and growth strategies. We generalize the problem of managing talent from a supply-demand standpoint through a resource acquisition lens, to an industrial business case where an organization recruits for multiple roles given a limited pool of potential candidates acquired through a limited number of recruiting channels. In this context, we develop an innovative analytical model in a stochastic environment to assist managers with talent planning in their organizations. We apply supply chain concepts to the problem, whereby individuals with specific competencies are treated as unique products. We first develop a multi-period mixed integer nonlinear programming model and then exploit chance-constrained programming to a linearized instance of the model to handle stochastic parameters, which follow any arbitrary distribution functions. Next, we use an empirical study to validate the model with a large global manufacturing company, and demonstrate how the proposed model can effectively manage talents in a practical context. A stochastic analysis on the implemented case study reveals that a reasonable improvement is derived from incorporating randomness into the problem

Detection of human papillomavirus DNA sequences in oral lesions using polymerase chain reaction

The purpose of the present study was to estimate the frequency of HPV DNA in four groups of oral lesions, including oral squamous cell carcinoma. Sixty paraffin-embedded oral tissue samples were examined for the presence of HPV DNAs using the PCR technique. These specimens were obtained from patients with oral squamous cell carcinoma (OSCC), leukoplakia, oral lichen planus (OLP), and pyogenic granuloma (PG). Consensus primers for L1 region (MY09 and MY11) and specific primers were used for detection of HPV DNA sequences in this study. we detected HPV DNA in 60% (9 out of 15) of OSCCs, 26.7% (4 out of 15) of leukoplakia, 13.3% (2 out of 15) of OLPs, and 6.7% (1 out of 15) of PGs. Statistical analysis showed that the prevalence of HPV in OSCC was significantly higher than other groups (P < 0.05). The frequency of HPV-16 and 18 detection in OSCC samples were 40% and 20%, respectively. The prevalence of these high risk HPVs was significantly higher in OSCC group (P < 0.05). The results of the present study show a successive increase of detection rate of HPV-16 and 18 DNAs from low level in samples of pyogenic granuloma and non-premalignant or questionably premalignant lesions of OLP to premalignant leukoplakia and to OSCC. © 2007 Tehran University of Medical Sciences. All rights reserved

Pathological Findings of Tramadol on Liver Tissue in the Cadaver Referred to Legal Medicine Organization of Tehran 2008-2013

Background: Tramadol is a synthetic opioid used to control chronic pain and pain after surgery. However, many cases of poisoning and dangerous side effects have been reported. In order to discover the causes of death in forensic medicine is usually examine tissue samples taken from the body, although the results of toxicology tests generally give us more information, but identifying the pathological effects of Tramadol on the internal organs, especially the livers can be very helpful.Methods: In this cross-sectional study, information on the history, the autopsy report and toxicology testing of patients who died due to poisoning Tramadol were studied. In this study, all of the information already provided by the use of particular forms collected and then analyzed using computer software SPSS.Results: A total of 49 cadavers were examined in this study. There were 39 dead (80%) of men and 10 of (20%) women. Most common age groups in the study were 24 to 34 years old (41%), 15 to 24 years old (39%), were reported. There were significant difference between liver microscopic spread among different ages, history of Tramadol, positive and negative toxicology tests stomach contents, urine, blood, tissue and vitreous. Most common pathological changes were in liver, degenerative changes and inflammatory cell infiltration in patients who under 35 years old.Conclusion: In this study, the majority of patients had acute poisoning with Tramadol, it can be concluded that the majority of changes in tissue obtained was as a result of acute Tramadol, respectively incidence of atelectasis and edema and alveolar bleeding in the liver were most pathological findings. In reviewing toxicology, Tramadol are also present in the stomach contents, urine, gall bladder, liver and blood were positive, the result of stomach contents will be most helpful for us

Comparative study on gonad development in rainbow trout (Oncorhynchus mykiss) reared in fresh and brackish water in the Yazd Province

Rainbow trout (Oncorhylichus mikiss) weidting 200±5 grams were used in this study to compare their gonad development in fresh and brackish water in Yazd Province. The culture period lasted 140 days from October to March 2003 during which time the temperature 03.8+0.6), pH (8.18±0.12) and dissolved oxygen (6.2+0.11) of fresh and brackish water were kept nearly constant. The salinity of fresh and brackish water was 0.4 -0.5 and 14.3-14.7ppt respectively. The fish were fed common commercial trout food (Chineh GFT2) based on temperature and biomass. Histological studies indicated that the gonad development is accelerated in brackish water where the males mature two month eal her than those reared in freshwater. The gonadosomatic index (G51) also affirmed the gonad development (P<0.05)