608 research outputs found

    Thermosolutal Marangoni boundary layer magnetohydrodynamic flow with the Soret and Dufour effects past a vertical flat plate

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    AbstractA numerical study of laminar magnetohydrodynamic thermosolutal Marangoni convection along a vertical surface in the presence of the Soret and Dufour effects has been performed. The diffusion-thermo implies that the heat transfer is induced by concentration gradient, and thermo-diffusion implies that the mass diffusion is induced by thermal gradient. In conformity to actuality, it is assumed that the surface tension varies linearly with both the temperature and concentration and that both interface temperature and concentration are quadratic functions of the interface arc length x. The general governing partial differential equations are converted into nonlinear ordinary differential equations using unique similarity transformations. The aim of this study is to investigate the effects of Hartmann number (0 ≤ M ≤ 5), thermosolutal surface tension ratio (0 ≤ R ≤ 5), Soret parameter (0.1 ≤ Sr ≤ 2), Dufour parameter (0.03 ≤ Du ≤ 0.6), Prandtl number (0.72 ≤ Pr ≤ 10) and Schmidt number (0.3 ≤ Sc ≤ 3) on the fluid velocity heat and mass transfer. It is found that, both of temperature and concentration gradient at the wall increases as the thermosolutal surface tension ratio increases. Also, the increase in Prandtl number results in an enhancement in the heat transfer at the wall

    Cattaneo–Christov heat flux impacts on MHD radiative natural convection of Al2O3-Cu-H2O hybrid nanofluid in wavy porous containers using LTNE

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    This paper aims to examine impacts of Cattaneo–Christov heat flux on the magnetohydrodynamic convective transport within irregular containers in the presence of the thermal radiation. Both of the magnetic field and flow domain are slant with the inclination angles Î© and Îł, respectively. The worked fluid is consisting of water (H2O) and Al2O3-Cu hybrid nanoparticles. The enclosures are filled with a porous medium, and the local thermal nonequilibrium (LTNE) model between the hybrid nanofluids and the porous elements are considered. Influences of various types of the obstacles are examined, namely, horizontal cold elliptic, vertical elliptic and cross section ellipsis. The solution methodology is depending on the finite volume method with nonorthogonal grids. The major outcomes revealed that the location (0.75, 0.5) is better for the rate of the flow and temperature gradients. The higher values of H* causes that the solid phase temperature has a similar behavior of the fluid phase temperature indicating to the thermal equilibrium state. Also, the fluid-phase average Nusselt number is maximizing by increasing Cattaneo–Christov heat flux factor

    Curcumin protection activities against Îł-Rays-induced molecular and biochemical lesions

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    BACKGROUND: Curcumin is a yellow-pigment phenolic compound used as a food spice and has a broad spectrum of antioxidant, anti-carcinogenic, anti-mutagenic and anti-inflammatory properties. METHODS: Radio-protective efficacy of curcumin; diferuloylmethane (C(21)H(20)O(6)) was evaluated using molecular and biochemical assays in male mice after exposure to 3 Gy γ-rays. Curcumin was given at a dose of 400 μmol/ kg body weight via gastric tubes for 5 following days either pre-, post- or both pre- and post-exposure. RESULTS: The incidence of aberrant cells and aberration types (mostly chromatids, breaks and fragments) was reduced with curcumin dosage as compared to irradiated group. Thiobarbituric acid reactive substances (TBARS), hydroperoxide (HP), xanthine oxidase (XO) and apoptotic markers (DNA- fragmentation and caspase-3 activation) were increased significantly, whereas levels of glutathione (GSH) and the enzymatic antioxidants [Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] were significantly depleted in γ-irradiated mice. Curcumin treatments of mice groups including the 5 days pre-irradiation treated group (protected), the 5 days post-irradiation treated group (treated), and the curcumin treated group 5 days pre- and post-irradiation (protracted), have attenuated the liver toxic effects of γ-rays as manifested by reducing the levels of TBARS, HP, XO and DNA fragmentation. Curcumin has also rescued the depletion of GSH and the enzymatic-antioxidant status. CONCLUSIONS: Curcumin has significant radio-protective and radio-recovery activities in γ-irradiated mice. It has antioxidant potential against γ-rays-induced cytogenetic, molecular and biochemical lesions in mice

    Between hope and fear: patient’s expectations prior to pelvic organ prolapse surgery

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    INTRODUCTION AND HYPOTHESIS: The aim of our study was to analyse the patient's expectations (fears and goals (hopes)) in women who are scheduled for pelvic organ prolapse (POP) surgery. METHODS: All consecutive women awaiting surgery for POP in a tertiary urogynaecological centre were included. A short questionnaire with two open questions on goals and fears with regard to the operation was used. RESULTS: Ninety-six out of 111 distributed questionnaires (86%) were analysed. Goals and fears were categorized into five groups. De novo symptoms (63%), POP recurrence (34%) and surgical complications (29%) were the most important fears. Symptom release (96%), improved lifestyle (physical capabilities; 30%) and improved sexual life (18%) were important goals. CONCLUSIONS: A wide variety of expectations both positive and negative can be found in women before POP surgery and should be an integral part of preoperative counselling. Achieving the individual goals as based on expectations, positive (goals) and negative (fears), should be part of the POP surgery evaluation

    Towards a multidimensional self-assessment for software process improvement: a pilot tool

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    The SPI Manifesto provides a framework for guiding software development organisations in their improvement efforts. Based on the Values of People, Business and Change, which are supported and informed by one or more of the ten principles, the designer and developer can avoid pitfalls, minimise risks and make their business successful. It has been established, in theory and practice, that improving the process results in improvement of the products and services emanating from that process. Following a number of earlier multidimensional analyses of the SPI Manifesto, carried out by the authors, a series of tabular representations identifying the nature, importance and strength of relationships between the Manifesto’s Values and Principles in terms of eight dimensions encapsulated in the acronym STEEPLED (Sociocultural, Technical, Economic, Environmental, Political, Legal, Ethical and Demographic) were developed. In this paper, we present a conceptualisation of a pilot automated tool (based on the STEEPLED Analysis), which could, potentially, be implemented/realised and used for self-assessment by software developing organisations. Starting with a self-assessment, current issues and requirements could be identified and revealed. The self-assessment using the pilot automated tool would, additionally, reveal areas requiring improvement, and would serve as a guide for the participating organisation to put focus on prioritising candidate process areas that require improvement. Also, the field testing of the pilot tool could enable the design and improvement of the tool itself, which, in turn, will be used in future for expert external/independent process assessment
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