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The phenomenon of secondary motion (acoustic streaming) created by the oscillation of a fluid past a sphere is investigated through numerically solving the full Navier–Stokes equations. The main parameters that affect the structure of acoustic streaming are Reynolds number and Strouhal number. The results are presented in the form of steady streaming patterns as well as the relation between Reynolds and Strouhal numbers and the dimensions of the streaming region.

A new result for integrals involving the product of Bessel functions and Associated Laguerre polynomials is obtained in terms of the hypergeometric function. Some special cases of the general integral lead to interesting finite and infinite series representations of hypergeometric functions.

The effect of sinusoidal fluctuations superimposed on the average free-stream velocity on mixed convection from a spherical particle is investigated. The parameters considered are the Reynolds number Re, Grashof number Gr, and the relative amplitude of fluctuations. The results indicate that due to the adverse pressure gradients created by the deceleration of the free-stream, separation may occur at a Reynolds number well below that at which it occurs in uniform flow. The rising buoyancy currents, however, weaken and possibly destroy the formation of vortices at the rear stagnation point. The average Nusselt number is found to increase with the increase of the amplitude of the free stream fluctuations and with the increase of Gr/Re2, as along as the flow does not reverse its direction. The time and space averaged Nusselt number increases with Gr/Re2, with the effect of the amplitude of the free-stream fluctuations becoming less pronounced at higher values of Gr/Re2. © 2007 American Institute of Chemical Engineers AIChE J, 2007

We show that the two dimensional Navier–Stokes equations in the stream function and vorticity form with nonhomogeneous boundary conditions have a unique solution with a stream function having two space derivatives.

Forced convection past a heated oblate spheroid is studied in an attempt to investigate the effect of the axis ratio on the heat transfer rate. The time-dependent full Navier–Stokes and energy equations are solved using a series truncation method. The axis ratios considered range from 1∕2 to 1 (a perfect sphere). The results for the flow and thermal fields are satisfactorily compared with relevant published research. The results are presented in the form of streamlines, isotherms, and the local and averaged Nusselt number distributions.

Motivated essentially by their possible need in a fairly large number of physical and chemical contexts, Mavromatis and Alassar [1] derived several associated Laguerre integral results by eliminating an unnecessary constraint used in an earlier paper on the subject by Mavromatis [2]. The main object of the present sequel to these recent works is to investigate and apply much more general families of integral formulas, involving products of two or more Laguerre polynomials, which have been considered in the mathematical literature rather extensively.

The synthetic organic azo dye sunset yellow is a widely used in food products, such as drinks, yoghurts, ice cream, and sweets. The solutions of this colored dye are not stable in sunlight or in dark, particularly when common food acids (e.g. citric acid and ascorbic acid) are present. The degraded products from sunset yellow are sulphanilic acid and the sodium salt of 2-naphthalene-sulphonic acid-5-amino-6-hydroxyl. These products further undergo deamination upon prolonged sunlight irradiation to produce benzene sulfonic acid sodium salt (BSA-Na) and ammonia as final products. The purpose of the study was to assess the toxicity BSA-Na on the liver and brain of male growing Sprague-Dawley rats. Oxidative stress and related gene transcription of the antioxidant enzymes have been assessed in male growing rats supplemented the different concentration of BSA-Na (34.8, 69.4 and 153.6 µg/kg. b.w.). The results showed that these concentrations of BSA-Na caused significant increase in the activity of the antioxidant enzymes total superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione reductase (GR) and xanthine oxidase (XO) and significant increase in lipid peroxidation level in liver and brain of growing male rats as compared with their control. A significant retardation in growth rate was observed in rat supplemented BSA-Na. In addition, these concentrations of BSA-Na significantly caused increasein Cu/Zn super oxide dismutase (Cu/Zn SOD) gene transcription. The data clearly demonstrate that BSA-Na can result in oxidative stress in both liver and brain of the growing rat.

An exact solution of the transient problem of potential flow past two identical circular cylinders is obtained. The two cylinders may be located at any distance from each other with the flow being perpendicular to the center-to-center line. The stream function formulation is used. The pressure distribution around the surfaces of the two cylinders is calculated and the effect of the center-to-center distance is studied. The exact solution is verified against that of the flow past a single cylinder by considering the limiting case when the center-to-center distance between the two cylinders increases indefinitely. Error bounds on the series solution show that the error decays exponentially.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'which patients should be on renin-angiotensin system blockers after coronary surgery?' Using the reported search, 12 papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The 12 studies included 5 prospective randomized controlled trials (RCTs) and 1 meta-analysis. One RCT of 2553 stable patients post-coronary artery bypass surgery (CABG) with left ventricular (LV) ejection fraction ≤40% showed that angiotensin-converting enzyme inhibition (ACEI) therapy can and probably should be delayed beyond 7 days due to increased cardiovascular morbidity and mortality associated with immediate postoperative initiation of ACEI treatment. Another study showed that the cardioprotective benefits of ACEI following CABG are persistent with respect to an LV ejection fraction below or above 40% and whether percutaneous coronary intervention (PCI) or CABG was performed. A large multicentre international study of 4224 patients undergoing CABG looking at a composite outcome of rates of cardiac, cerebral and renal events and in-hospital mortality showed that continuous treatment with ACEI compared with no ACEI was associated with reductions of risks of non-fatal events (P = 0.009, odds ratio 0.69, 95% confidence interval 0.52-0.91). Addition of ACEI de novo following surgery was also associated with significant reduction in the risk of the composite outcome (P = 0.004) and of a cardiovascular event (P = 0.04). We conclude that angiotensin-converting enzyme inhibitor treatment plays an important role in minimizing ischaemic events after CABG even in low-risk patients. The cardioprotective benefits of these drugs are persistent at mid- and long-term follow-up, with respect to LV ejection fraction below or above 40% and whether PCI or CABG was performed. Not only continuation of angiotensin-converting enzyme inhibition early after surgery but also adding ACEI de novo postoperatively can be associated with better cardiovascular and renal outcomes.

This study investigated the efficacy of prophylactic intraoperative intra-aortic balloon pump (IABP) usage in chronic heart failure patients with severely reduced left ventricular function undergoing elective cardiac surgery. Between January 2008 and December 2012, 107 patients with severely reduced left ventricular ejection fraction (LVEF35%) received prophylactic intraoperative IABP implantation during open-heart surgery. Surgical procedures performed were isolated coronary artery bypass grafting (CABG) in 35 patients (32.7%), aortic valve replacement in 12 (11.2%), mitral valve repair or replacement in 15 (14.0%), combined valve and CABG procedures in 27 (25.2%), and other surgical procedures in 18 (16.8%). Results and outcomes were compared with those in a propensity score-matched cohort of 107 patients who underwent cardiac surgery without intraoperative IABP implantation. Matching criteria were age, gender, LVEF, and surgical procedure. Duration of intensive care unit (ICU) stay, duration of hospital stay, and 30-day mortality were markers of outcome. In the IABP group, mean patient age was 69.1 ± 13.7 years; 66.4% (70) were male. All IABPs were placed intraoperatively. Mean duration of IABP application time was 42.4 ± 8.7 h. IABP-related complications occurred in five patients (4.7%), including one case of inguinal bleeding, one case of mesenteric ischemia, and ischemia of the lower limb in three patients. No stroke or major bleeding occurred during IABP support. Mean durations of ICU and hospital stay were 3.38 ± 2.15 days and 7.69 ± 2.02 days, respectively, in the IABP group, and 4.20 ± 3.14 days and 8.57 ± 3.26 days in the control group, showing statistically significant reductions in duration of ICU and hospital stay in the IABP group (ICU stay, P = 0.036; hospital stay, P = 0.015). Thirty-day survival rates were 92.5 and 94.4% in the IABP and control group, respectively, showing no statistically significant difference (P = 0.75). IABP usage in chronic heart failure patients with severely reduced LVEF undergoing cardiac surgery was safe and resulted in shorter ICU and hospital stay but did not influence 7- and 30-day survival rates.

This paper deals with the problem of oscillating viscous flow over an oblate spheriod. The flow is assumed incompressible and axisymmetric and the motion is governed by the Navier-Stokes equations. The method of solution is based on the series truncation method where the stream function and vorticity are expressed in terms of a finite series of Legendre functions. The effects of the Reynolds and Strouhal numbers on the flow characteristics are studied and compared with previous available solutions. Results are presented for the periodic variation of the drag coefficient, surface vorticity and pressure distributions for Reynolds numbers ranging from 5 to 100 and Strouhal numbers ranging from π/4 to π while keeping the spheroid axis ratio unchanged. The time variation of the velocity field during one complete oscillation is presented in the form of streamline and equi-vorticity patterns. The periodic variation of the angle of separation as well as the length of the separation bubble are also presented. The double boundary layer structure previously observed in the case of a sphere is also detected.

In this paper, a generalized formula for the definite integral of three associated Legendre polynomials of the first kind that arises in various physical applications is given in terms of the 3 F 2 hypergeometric function and the 3 − j symbols. The special case, when the integral reduces to a particularly simple familiar expression, is also mentioned.

The problem of heat convection from a sphere placed in an oscillating viscous free stream is considered for the two cases of forced and mixed convection regimes. The sphere surface is assumed isothermal and the free-stream oscillations are always in the vertical direction resulting in axisymmetric flow and thermal fields for both regimes. The study is based on the solution of the unsteady Navier–Stokes and energy equations for a Boussinesq fluid of constant Prandtl number (Pr=0.71) . The main parameters considered are the Reynolds number, Grashof number, and Strouhal number. Comparison of results with published data shows a good agreement for the special case of steady forced and mixed convection. The details of the resulting thermal fields are presented in the form of isotherm patterns and the local Nusselt number distribution.

The need to increase the water supply of the Kingdom of Saudi Arabia to keep up with the industrial and agricultural development cannot be overemphasized. Several ways exist to enhance the available supplies. One such method is the utilization of storm runoff from urban areas after appropriate treatment. In this study, the possibility of using urban runoff for industrial, irrigation, and other municipal uses after appropriate treatment is investigated. To achieve this, a representative urban watershed in the city of Dhahran was used and the runoff quantity and quality were determined over a four-year study period. The quality parameters considered were suspended solids (SS), total dissolved solids (TDS), alkalinity, hardness, chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), nitrite plus nitrate, phosphorous (P), chlorine (Cl), sulfate, grease and oil, coliforms, and heavy metals. The data obtained on the quantity and quality of the runoff in this city were further analyzed and the lev...

The axisymmetric viscous oscillating flow over a prolate spheroid is considered. The oscillations are harmonic and the free stream is always parallel to the spheroid major axis. The flow is governed by the Strouhal and the Reynolds numbers as well as the spheroid axis ratio. In the present paper, we only investigate the effect of Reynolds number while keeping the Strouhal number and the axis ratio unchanged. The results are presented in terms of the periodic variation of the drag coefficient, pressure, surface vorticity, separation angle, the wake length, and the streamline and vorticity patterns for Reynolds numbers ranging from 5 to 100. Upon averaging the stream function and vorticity over one complete oscillation, the double boundary-layer structure observed in the case of a sphere is confirmed for the range of parameters considered.

This paper deals with the problem of oscillating viscous flow over a sphere. The flow is assumed axisymmetric and governed by the Navier-Stokes equations for incompressible fluids. The method of solution is based on the series truncation method where the stream function and vorticity are expressed in terms of a finite series of Legendre and first associated Legendre functions. The effects of the Reynolds and Strouhal numbers on the flow characteristics are studied and compared with available data from previous work and also from potential flow solutions. Results are presented for periodic variation of the drag coefficient, surface vorticity and pressure distributions for Reynolds numbers ranging from 5 to 200. The time variation of the velocity field during one complete oscillation is presented in the form of streamline and equivorticity patterns. The periodic variation of the angle of separation as well as the length of the separation bubble are also presented. Calculations are performed for the time-averaged stream function and vorticity through which the double boundary layer structure is confirmed for the range of Reynolds and Strouhal numbers considered.

An analytical solution is obtained for the problem of axisymmetric inviscid incompressible flow over a prolate spheroid placed in an oscillating free stream. The oscillations are harmonic and the free stream is always parallel to the spheroid major axis. The flow is governed by the Strouhal number and the spheroid axis ratio. Analytical expressions are obtained for the potential function, the surface pressure distribution, and the hydrodynamic force coefficient. The solution covers a wide range of spheroidal shapes ranging from a sphere at one end to a thin needle at the other.

The hydrodynamic forces acting on an oblate spheroid placed in an oscillating free stream are obtained for the special case of inviscid flow. The flow is assumed incompressible and axisymmetric and the free stream oscillations are harmonic. The flow direction is always along the spheroid's axis of symmetry. Analytical expressions are obtained for the potential and stream functions as well as the surface pressure distribution and the hydrodynamic force coefficient. The analysis is based on the solution of the unsteady equations of motion and continuity in oblate spheroidal coordinate system. The parameters involved are the major to minor axes ratio and the Strouhal number. The solutions for the two limiting cases of oscillating flows over disks and spheres can be easily obtained from the presented analytical solution.

In this paper, an exact solution of Hagen–Poiseuille flow in microchannels with semi-elliptic cross sections is obtained. The velocity, shear stress distribution, and the friction factor are calculated and compared to known approximate solutions in the literature. The solution is also verified by comparing the limiting case when the axis ratio approaches unity to the exact solution obtained for semicircular channels.

The transient heat conduction from two parallel isothermal cylinders is studied using the naturally fit bipolar cylindrical coordinates system. The energy equation is expanded in a Fourier series using appropriate basis functions to eliminate one of the physical coordinates. The resulting modes of the expansion are solved using a finite difference scheme. It is shown that, as is the case with a single isothermal cylinder in an infinite medium, steady states for two isothermal cylinders are not possible and heat transfer changes indefinitely with time.

Controlling robot manipulators is challenging due to their nonlinearity nature. PID control is still the benchmark control in industry due to its simplicity. Nonlinear control techniques are very complex and are not attractive. However, fuzzy control is more attractive and provides good performance. This paper p combines fuzzy control with PID control to produce supervisory fuzzy PID controller for a 5DOF robot arm system. This proposed control works online to give better performance Simulation results using MATLAB/SIMULINK shows better results.

Novel synthesis of α-substituted-β-enaminonitriles could be obtained from reaction of β-enaminonitriles with paraformaldehyde and dimethylamine. Such compounds reacted readily with a wide variety of reagents to give unique heterocyclic systems.

In this paper, an exact solution of Hagen-Poiseuille flow in channels of semi-circular cross-sections is obtained as no such available in the literature. The velocity profile across the cross section and the shear stress distribution along the wall of the channel are calculated.

Controlling robot manipulator is essential problem to guarantee the robot execute the desired task with minimum error. This paper presents a fuzzy logic controller (FLC) for manipulating 5DOF robot arm based on independent joint control method. The proposed controller design aims to overcome the drawbacks of classical PID controller. The simulation is done using Matlab/ SIMULINK by comparing the performance of the two controllers for Lynx6 robot arm in terms of time response. Based on the simulation results, the FLC provides good results than PID controller.