ISSN: 1817-2695

Volume 33, Issue 4

Volume 33, Issue 4, Autumn 2007, Page 1-105


The study of the Cr4+:Y2SiO5 crystal coupling coefficients as a solid Q-switch for the chromic solid-state lasers

Sahib Nima Abdul-Wahid; Methaq Mutter Al-Sultany

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 1-15

The passively Q-switching method has been used for the chromic solid-state lasers such as ( Ruby , Alexandrite , Cr:LiCAF , Cr:LiSAF ) lasers with Cr4+:Y2SiO5 solid-state crystal. We have studied the saturable absorber crystal properties which are used in passive Q-switching all these lasers . The molar extinction coefficient (ε ) , coupling coefficient of the saturable absorber ( Ka ) , the optical density (d ) , the ground-state absorption cross-section (σa ) of Cr 4+:Y2SiO5 , and the Q-switching efficiency ( η ) of the chromic solid-state lasers is calculated first, when the pumping rate ( Rp ) was variable and other parameters (as reflectivity of output coupler ( R ) and the number of molecules in the ground-state ( Naо ) were constant) and second , ( η ) is calculated when ( R ) was variable and other parameters were constant . The results of Cr 4+:Y2SiO5 crystal which is used with all these lasers are compared each others , and the behavior of (ε ), and ( Ka ) had been interpreted according to ( σ ), and (d ) , respectively . The Cr 4+:Y2SiO5 Q-Switched Cr:LiSAF laser has a better passive Q-Switching performance than other used laser systems . The main conclusion in this research is that the molecular weight of the chromic ion host laser crystal acts as an important role in Q-Switching efficiency where it is directly proportional with the Q-switching efficiency.

PARAMETRIC STUDY OF GAS TURBINE CYCLE WITH FOGGING SYSTEM

Q.A. Rishack and S.J. AL-Mousawi; K.Y.AL-Salman

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 16-22

Fogging system is used as a method for cooling the inlet air to the compressor
by the direct injection of water, in order to reduce the ambient air temperature
until it reaches the wet bulb temperature and thus increasing the net power.
The effects of ambient temperature, relative humidity, firing temperature, and pressure
ratio on the open cycle gas turbine performance are studied. The ambient temperature
range, which is considered in this study, ranged from (10 to 60°C); the relative humidity
range was (10% to 90%), the pressure ratio range was (3 to 23) and the firing temperatures

were 1100K, 1200K, 1400K, and 1600K. The results of this study showed that output
power and efficiency increase continuously with increasing the firing temperature, and
reduces with increasing the ambient temperature, and the efficiency increases with
pressure ratio reaching a maximum value then it begins reducing. When the relative
humidity increases it is gives a reverse effect on the power and efficiency of this cycle.
The present work reveals that using fogging system in the front of the compressor in
the open cycle gas turbine can improve the efficiency and enhance the output power of the cycle due to reducing the inlet air temperature interring to the compressor

Some Spectroscopic and Thermodynamic Studies of Charge Transfer

Shaker A.N.AL-Jadaan

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 23-43

The π→π* charge transfer(CT) complexes of 2,3-dichloro-5,6-dicyanobenzoquenone
(DDQ) with some phenol derivatives have been investigated spectraphotometrically in
chloroform solution. The equilibrium constant (K) and extinction coefficient (ε) and the
dissociation energies of the complexes excited state (w) of charge transfer have been calculated
and discussed. The ionization potential of phenol derivatives have estimated.

Quadratic Zeeman Effect for an s-electron Moving in a Screened Coulomb Potential

H.A.Kassim

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 44-57

The s-level of a screened hydogenic atom in a uniform magnetic field of arbitrary strength B have been calculated accurately. First, the related spherical symmetric case has been treated by using the linear variational method. The trial wave function is taken as linear mixture of hydogenic and 3D harmonic oscillator wave functions of s-symmetry.Second, the actual nonspherical case is studied by adopting the correction proposed by Mustafa and Chhajlany [14]. The latter accounts for the difference between the two cases in an approximate way by utilizing the properties of the 2D and 3D harmonic oscillators. We start our study with the unsceened hydrogen case to recover their shifted results and deal then with the more involved case of the screened hydrogen atom covering wide ranges of the applied field and of the screening length.

High Order Finite Difference Scheme for One Dimensional Heat Transport Equation at the Microscale.

Akil J. Harfash; Shatha A. Mahdi; and

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 58-69

A sixth order compact difference scheme for space with Crank-Nicholson scheme for time is employed to solve one dimensional microscale heat transport equation. The unconditionally stability of this new version of finite difference scheme is proved with respect to initial values. Numerical experiments are introduced to test the accuracy of the sixth order compact finite differences and compare it with both the second order and fourth order difference schemes. Our Numerical results showed that the sixth order compact scheme is computationally more efficient and more accurate than the second and fourth order schemes.

Fourth Order Compact Finite Difference Scheme for Two-dimensional Microscale Heat Equation.

Assma J. Harfash

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 70-80

In this paper, fourth order compact difference scheme is employed to solve two dimensional microscale heat transport equation. By introducing an intermediate function for the heat transport equation, we use the fourth order compact scheme for the space with a second order Crank-Nicolson scheme for the time. The stability of this scheme is proved unconditionally stable with respect to initial values. The computational accuracy is demonstrated that the results of the compact fourth order finite difference scheme is more accurate than the second order finite difference scheme [12].

Hiding Data Using LSB-3

Aiad Ibraheem Abdul-Sada

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 81-88

In this paper, a new steganography method based on the spatial domain is proposed. Instead of using the LSB-1 of the cover for embedding the message, LSB-3 has been used to increase the robustness. LSB-1,2 may be modified according to the bit of the message, to minimize the difference between the cover and the stego-cover. For more protection to the message bits a stego-Key has been used to permute the message bits before embedding it. Experimental results of the modified method shows that PSNR is grater than the conventional method of LSBs replacement.

THE EFFECT OF SOME MEDICAL PLANT EXTRACTS ON THE INTERCELLULAR FORM OF LEISHMANIA

Al. Hadithi; baqi; O. G. Al-Mawla; Saleem; and Ismail; J.Al-Ani; Abdul

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 89-92

Extracts of the plants ( Astragalus hamosus , Nerium oleander, Ficus carica, Peganum harmala, Punica granatum & Glycyrrhiza globra ) were investigated for their antileishmanial activities against the intracellular amastigotes of Leishmania donovani and Leishmania major .
The procedure adopted was the tissue culture for peritoneal macrophage of BALB/C mice, which were infected and investigated in- vitro.
The results showed that the extracts of the plants A. hamosus & N. oleander exhibited good activity against intracellular amastigotes, whereas the extracts of F. carica & p. hamosus requires higher concentrations to destroy the parasites.

The effect of phenobarbital sodium on the The Thyroid Gland in Rabbits

Damya Qasim Sukker; Abdul Jabbar Rasmi

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 93-96

The present study was design to observe the effect of Phenobarbital sodium on the thyroid gland of rabbits. A dose of(75mg/kg) was injected intramuscularly to the rabbits for (17) days. The study revealed a histological changes include decrease in follicular size and a major decrease in size of the follicular lumen.

Some Spectroscopic and Thermodynamic Studies of Charge Transfer Comlexes of DDQ and Some Phenol Derivatives

Shaker A.N.AL-Jadaan

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 97-100

The π→π* charge transfer(CT) complexes of 2,3-dichloro-5,6-dicyanobenzoquenone (DDQ) with some phenol derivatives have been investigated spectraphotometrically in chloroform solution. The equilibrium constant (K) and extinction coefficient (ε) and the dissociation energies of the complexes excited state (w) of charge transfer have been calculated and discussed. The ionization potential of phenol derivatives have estimated.

Dodecylbenzenesulfonic acid doping of Polyaniline and Poly-3-methylaniline Studied by Resonance Raman Spectroscopy

Ammar K. Al-Ba

Journal of Basrah Researches (Sciences), Volume 33, Issue 4, Pages 101-105

Dodecylbenzenesulfonic acid doping of Polyaniline and Poly-3-methylaniline
In this work resonance Raman spectroscopy is used for the characterization dodecyl benzensulfonic acid doping polyaniline and poly-3-methylpolyaniline. Raman spectra were recorded with the excitation lines from the blue range to the red region. As expected results are clearly affected during both processes to all polyanilines substituted. These modifications can be interpreted in terms of electronic and conformational changes of the chains, consistent with an increase of the conjugation length and of the delocalization of polarons. These results lead to a clear understanding of photo-induced IR spectra recorded on the same samples