Approximate Solutions for the Flow and Heat Transfer due to a Stretching Sheet Embedded in a Porous Medium with Variable Thickness, Variable Thermal Conductivity and Thermal Radiation using Laguerre Collocation Method

In this article, a numerical approach is given for studying the flow of a Newtonian fluid over an impermeable stretching sheet embedded in a porous medium with a power law surface velocity and variable thickness in the presence of thermal radiation. The flow is caused by a non-linear stretching of a sheet. Thermal conductivity of the fluid is assumed to vary linearly with temperature. The governing PDEs are transformed into a system of coupled non-linear ODEs which are using appropriate boundary conditions for various physical parameters. The proposed method is based on replacement of the unknown function by truncated series of well known Laguerre expansion of functions. An approximate formula of the integer derivative is introduced. The introduced method converts the proposed equations by means of collocation points to a system of algebraic equations with Laguerre coefficients. Thus, by solving this system of equations, the Laguerre coefficients are obtained. The effects of the porous parameter, the wall thickness parameter, the radiation parameter, thermal conductivity parameter, and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction and Nusselt numbers are presented. Comparison of obtained numerical results is made with previously published results in some special cases. The results attained in this paper confirm the idea that the proposed method is powerful mathematical tool and it can be applied to a large class of nonlinear problems arising in different fields of science and engineering

Employment Security in Egypt in Light of the COVID-19 Pandemic: Rethinking Policies and Practices

Crises such as COVID-19’s have inequitable impacts on different countries, various population groups and diverse sectors of society and the economy. Areas of work and employment were met with a lot of challenges worldwide, and in particular in countries like Egypt with a large sector of vulnerable and precarious workers. This policy paper addresses the question of employment security both in response to crises such as COVID-19, and on the long term. To do so, the research maps ‘vulnerable work’, including informal labor, labor in the gig economy, self-employed and other types of precarious work. It then assesses Egypt’s policy responses to COVID-19 with regards to the issues of unemployment and informal labor, including by assessing the efficacy of the irregular workers’ fund and the diverse methods used to finance the crisis. Although some of those responses were in the right direction, their shortcomings revealed much deeper structural obstacles within employment relations and existing labor market vulnerabilities. This research thus provides policy recommendations, both on the short term in response to the crisis, as well as longer term to address vulnerability and precariousness in the world of employment in Egypt

Antisense Phenotypes Reveal a Functional Expression of OsARF1, an Auxin Response Factor, in Transgenic Rice

OsARF1 is the first full-length member of auxin response factor (ARF) gene family to be cloned from monocot plant. Using quantitative RT-PCR this study found that, the transcript abundance of OsARF1 was significantly higher in embryonic tissues than in vegetative tissues. To investigate the effect of OsARF1 on the phenotype of rice, a cDNA fragment of OsARF1 was inserted in inverse orientation to the 35S promoter in vector pBin438 to produce an antisense (AS) construction. The AS-OsARF1 construct was transferred into rice (Oryza sativa L. japonica ) calli via Agrobacterium tumefaciens -mediated transformation. Molecular analysis of transgenic plants showed that the functional expression of OsARF1 was inhibited at mRNA level efficiently. The AS-OsARF1 plants showed extremely low growth, poor vigor, short curled leaves and tillered but were sterile. Therefore, the OsARF1 was shown to be essential for growth in vegetative organs and seed development

(R1989) Mixed Convection Slippery Cross Fluid Flow due to a Stratified Sheet under the Effect of Radiation Phenomenon

In view of the meaning of a two dimensional laminar Cross liquid in depicting an exhaustive assortment of experimental information, an assessment is done for a numerical and mathematical arrangement over a stratified extensible sheet. The non-dimensionality technique is brought into the controlling equations within the sight of the slip phenomenon and to make the solution more thorough. The data have been taken at a steady, viscous and laminar ow. Heat transfer across fluid is employed as a non-Newtonian fluid, where the fluid has a affected by radiation. Additionally, thermal radiation and heat generation are considered with the basic influence on the temperature field. The work has been performed to yield a completely new concept of the presence relationship between the governing parameters and the rate of heat transfer. Numerical analysis with the aid of the shooting method of the governing equations of motion is given over a wide range of controlling parameters. A bunch of graph plots both velocity and temperature fields at various upsides of physical parameters. Furthermore, a tabular form of the same parameters exists for the local shear stress and the rate of heat transfer along the sheet

Fundoplication in neurologically impaired children: Nissen or Thal?

Background/purpose Gastroesophageal reflex disease (GERD) is a highly prevalent problem in infants and children with severe neurological impairment (33–75%). It occurs in 44–67% of children undergoing antireflux surgery. This study is conducted to compare the results of fundoplication, according to the Nissen and Thal procedure for management of GERD in neurologically impaired children.Materials and methods Between May 2007 and January 2011, 69 neurologically impaired children with severe GERD underwent fundoplication (Nissen= 32, Thal= 37) with construction of a Stamm gastrostomy tube in 58 patients. The male-to-female ratio was 1.6 : 1; the mean age was 1.8 years. Preoperative workup of the patients included upper gastrointestinal tract contrast series, upper gastrointestinal tract endoscopy, and a 24-h pH study.Results Perinatal asphyxia was the most common cause of neurological impairment (30.4%). Feeding dysfunction represented the most common indication for surgery (52.2%). Recurrence of symptoms was found in 14 patients (20.3%); 10 patients (14.5%) died because of respiratory failure. Acid pH-metry showed a statistically significant difference between preoperative and postoperative data; however, this difference was insignificant on comparing the postoperative parameters of the Nissen fundoplication group with the Thal fundoplication group.Conclusion GERD in neurologically impaired children is a very common problem associated with a high failure rate after properly performed fundoplication. In our series, the outcome of Thal fundoplication showed an insignificant difference when compared with that of Nissen fundoplication with less dissection and less dysphagia or gas bloat. Long-term evaluation is needed as incidence of recurrence increases with time secondary to the persistent comorbidities. Further refinement of management strategies is required to decrease incidence of recurrence and to improve the overall quality of life. Keywords: fundoplication, gastroesophageal reflux disease, neurological impairmen

Powder Bed Layer Characteristics: The Overseen First-Order Process Input

A discrete element powder model is used in conjunction with a finite volume melting model on the first layer of a powder bed selective laser melting process