An Nasiriyah, Iraq

University of Thi-Qar
An Nasiriyah, Iraq

Thi Qar University is an Iraqi university located in Nasiriyah, Iraq. It was established in 2000. Originally, the university was a branch of the University of Basrah, and the branch was established in 1992. Its first graduating class was in 1996. In 2000, the branch became independent of Basrah University and Thi Qar University was founded. Wikipedia.

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Abeed Al Mashkor I.M.,University of Thi-Qar
International Journal of Pharmacognosy and Phytochemical Research | Year: 2014

Fenugreek (Trigonella foenum-graecum) is a nutrient dense food rich in beneficial phytochemicals. In this study, three types of solvent extracts of fenugreek seeds were used to examine the effects of extraction solvent on total phenolics content (TPC), 1,1-diphenyl-2-picryl hydrazyl radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP) were determined. Results showed that extraction solvent had significant effects on TPC and antioxidant activity of acetone extract. The highest content of TPC and antioxidant activity (FRAP and DPPH) were found in 50% acetone extracts. The TPC for fenugreek seeds from 25.90 to 15.45 mg GAE/100 g DW and antioxidant activity FRAP from 47.49 to 31.85 mg TE /100 g DW, DPPH were from 67.30 % to 43.61%). The largest amount of total phenol content which leads to more effective radical scavenging effect was shown by 50% acetone extract. Moreover, amount of phenolic compounds and antioxidant activities increased in acetone extract. Acetone 50% and methanol 50% solvent showed the greatest capability in extracting antioxidants and inhibiting the free radicals produced. It was concluded that extraction solvent play important roles on the phenolics compounds and their antioxidant activity of fenugreek seeds extract. © 2014–2015, International Journal of Pharmacognosy and Phytochemical Research. All rights reserved.

Oztop H.F.,Firat University | Mushatet K.S.,University of Thi-Qar | Yilmaz T.,Erciyes University
International Communications in Heat and Mass Transfer | Year: 2012

A numerical study has been conducted to analyze the turbulent forced convection heat transfer for double forward facing step flow with obstacles. Obstacles have rectangular cross-sectional area with different aspect ratio that is located before each step. The numerical solutions of continuity, momentum and energy equations were solved by using a commercial code which uses finite volume techniques. The effect of turbulence was modeled by using a k-ε model. The effects of step height, obstacle aspect ratio and Reynolds number on the flow and heat transfer are investigated. The obtained results show that the rate of heat transfer is enhanced as aspect ratio of obstacle increases and this trend is affected by the step height. Also the results verified that the pressure drop decreases as obstacle aspect ratio increases. © 2012 Elsevier Ltd.

Togun H.,University of Thi-Qar
International Communications in Heat and Mass Transfer | Year: 2016

Heat transfer in flow channels can be improved by using passive techniques such as ribs on wall and change cross section area where these modifications have practical engineering application for thermal power plant, refrigerators, and radiators. Effects of separation flow and nanofluids on thermal performance for laminar range presented experimentally and numerically in this review. The augmentations of heat transfer with fluid and nanofluid flow through sudden expansion, over backward and forward facing step, and rib channels have been concerned. The experimental results showed good agreement with numerical results and indicated the effects of separation flow and nanoparticles on augmentation of heat transfer rate. The results showed increase in Nusselt number with increase of Reynolds number, step height, and number of ribs. It was detected that by increasing the nanoparticle volume concentrations of nanofluids, improves the heat transfer coefficient. Also different nanoparticles used in the literature investigations are based on thermal conductivity where enhancement of heat transfer rate was obtained significantly. © 2016 Elsevier Ltd

Hasan M.I.,University of Thi-Qar
Applied Thermal Engineering | Year: 2011

The aim of this paper is to study the flow and heat transfer of microencapsulated phase change material (MEPCM) suspension in counter flow microchannel heat exchanger (CFMCHE) and it's effect of the performance of this heat exchanger when using this suspension as a coolant instead of pure fluid. The hydrodynamic and thermal characteristics of this suspension flows in microchannels of CFMCHE is numerically investigated. The MEPCM suspension used in this paper consists of microcapsules constructed from n-octadecane as a phase change material (PCM) and the shell material is polymethylmethacrylate, these capsules are suspended in water in a concentration of (0-20)%. From the results, using of MEPCM suspensions as a cooling fluid lead to modify thermal performance of a CFMCHE by increasing its effectiveness but it also lead to increase the pressure drop. From heat transfer (thermal performance) point of view it is better to use this type of fluid to increase cooling efficiency of a CFMCHE, but due to extra increase in pressure drop it leads to reduce the overall performance compared with pure fluids. Therefore its use depends on the application at which this heat exchanger is used. © 2010 Elsevier Ltd. All rights reserved.

Mohamad H.K.,University of Thi-Qar | Mohamad H.K.,Voronezh State University
Journal of Magnetism and Magnetic Materials | Year: 2011

I studied the ferrimagnetic Ising model with nearest neighbour interactions for a square lattice and simple cubic one, using mean field theory. The free energy of a mixed spin Ising ferrimagnetic model was calculated from a mean field approximation of the Hamiltonian. By minimizing the free energy, I obtained the equilibrium magnetizations and the compensation temperatures. Clear indications of the single-ion anisotropies on the compensation points of the mixed spin-3/2 and spin-5/2 ferrimagnetic lattices are found. Some interesting behaviors of these systems are obtained depending not only on the values of magnetic anisotropies for both sublattice sites but also on the lattice structure. The longitudinal magnetic fields dependence of the spin compensation temperature is the main focus of research. The possibility of many compensation temperatures is indicated. © 2010 Elsevier B.V. All rights reserved.

Al-Nashy B.,University of Basrah | Al-Nashy B.,Missan University | Amin S.M.M.,University of Basrah | Al-Khursan A.H.,University of Thi-Qar
Journal of the Optical Society of America B: Optical Physics | Year: 2014

We have introduced a Y-configuration model from the double-quantum-dot (QD) system to study third-order Kerr nonlinearity based on the density-matrix method. Inhomogeneity in QDs has been included in the calculations of the real (Kerr) and imaginary (absorption) parts of the density matrix, which has not been covered in the earlier Kerr calculations. Our system exhibits high controllability with a single parameter. Giant Kerr dispersion, propagation without distortion, wide electromagnetic-induced transparency, and switching between subluminal to superluminal propagation are obtained by tuning its fields. Controlling and cycling fields can also control the system in addition to the pump field. © 2014 Optical Society of America.

AL-Badry L.F.,University of Thi-Qar
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2016

We discuss the influence of nanostructure geometry on the thermoelectric properties in quantum ring consists of one QD in each arm, each QD connects with side QD. The calculations are based on the time-dependent Hamiltonian model, the steady state is considered to obtain an analytical expression for the transmission probability as a function of system energies. We employed the transmission probability to calculate the thermoelectric properties. We investigate thermoelectric properties through three configurations of this nanostructure. Figure of merit enhanced in configuration (II) when side QD connected to upper arm of quantum ring. The magnetic flux threads quantum ring. The effect of magnetic flux on the thermoelectric properties is examined. © 2016 Elsevier B.V.

Hasan M.I.,University of Thi-Qar
Applied Thermal Engineering | Year: 2014

In this paper a micro pin fin heat sink is numerically investigated with three fins geometries (square, triangular and circular) in addition to the unfinned microchannel heat sink. Nanofluid is used as a cooling fluid, since the flow and heat transfer have been studied with two types of nanofluids (Diamond-water and Al2O3-water) in addition to the pure water. The volumetric concentration of selected nanofluids has been chosen in range (1-4)%. The comparison of hydrodynamic and thermal characteristics of different fin geometries and cooling fluids has been made under the same value of Reynolds number and constant wall temperature thermal boundary condition, the range of Re used is (100-900) to ensure that, the flow remains in the laminar regime. The results obtained indicated that, using of nanofluid instead of pure fluid as a coolant leads to enhanced heat transfer performance by increasing the amount of heat dissipated but it also leads to increased pressure drop for all fins shapes and nanofluids studied. © 2013 Elsevier Ltd. All rights reserved.

Flayyih A.H.,University of Thi-Qar | Flayyih A.H.,The University of Mustansiriyah | Al-Khursan A.H.,University of Thi-Qar
Applied Optics | Year: 2013

The theory of four-wave mixing (FWM) in the quantum dot (QD) semiconductor optical amplifiers (SOAs) is discussed by combining the Q Drate equations system, the quantum-mechanical density-matrix theory, and the pulse propagation in QD SOAs including the three region of QD structure ground state (GS), excited state (ES), and wetting layer. Also, relations for differential gain, gain integral, and nonlinear susceptibility of both pump, probe, and signal pulses were discussed. Gain and differential gain have been calculated for QD structure. FWM efficiency and its components [spectral hole burning (SHB), carrier heating, and carrier density pulsation] are calculated. It is found that inclusion of ES in the formulas and in the calculations is essential since it works as a carrier reservoir for GS. It is found that QD SOA with enough capture time from ES to GS will reduce the SHB component, and so it is suitable for telecommunication applications that require symmetric conversion and independent detuning. © 2013 Optical Society of America.

Mushatet K.S.,University of Thi-Qar
Thermal Science | Year: 2011

Simulation is presented for a backward-facing step flow and heat transfer inside a channel with ribs turbulators. The problem was investigated for Reynolds numbers up to 32000. The effect of a step height, the number of ribs and the rib thickness on the flow and thermal field were investigated. The computed results are presented as streamlines counters, velocity vectors, and graphs of Nusselt number and turbulent kinetic energy variation. A control volume method employing a staggered grid techniques was imposed to discretize the governing continuity, full Navier-Stockes and energy equations. A computer program using a SIMPLE algorithm was developed to handle the considered problem. The effect of turbu-lence was modeled by using a k-j{cyrillic, ukrainian} model with its wall function formulas. The obtained results show that the strength and size of the recirculation zones behind the step are increased with the increase of contraction ratio (i. e. with the in-crease of a step height). The size of recirculation regions and the reattachment length after the ribs are decreased with increasing of the contraction ratio. Also the results show that the Reynolds number and contraction ratio have a significant effect on the variation of turbulent kinetic energy and Nusselt number.

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