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alkej-271
Modeling of Mass Transfer Coefficient in Rotating Biological Contactor with Perforated Discs (RPBC)
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Abstract

 In order to make an improvement associated with rotating biological contactor (RBC), a new design of biofilm reactor called as Rotating perforated disc biological contactor (RPBC) was developed in which the rotating discs are perforated. The transfer of oxygen from air to wastewater was investigated. Mass-transfer coefficient (KLa)  in the liquid phase was determined by measuring  the rate transfer of oxygen.  A   laboratory scale of (RPBC) consisted of a semicircular trough was used with a working capacity of 40 liters capacity of liquid. Synthetic wastewater was used as a liquid phase, while air was used as a gas phase.

The effects of many parameters on the liquid phase mass transfer coefficient (KLa) were investigated. These parameters are; the disc rotational speed (N), the pore diameter (d) and clearance between the discs(C). It was found that the value of KLa was increased as the rotation speed (N) increased, and as  the diameter of the pores in  the disc  (d) increased. While the values of (KLa) was decreased continuously with increasing the clearance(C). Suitable correlation was developed for estimating mass transfer coefficient (KLa) in this type of bioreactor.

 Keywords: Rotating biological contactor, Mass transfer coefficient, Wastewater treatment.

 

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Publication Date
Mon Mar 03 2025
Journal Name
Internationaljournalof Economicsandfinancestudies
CROSS-SECTIONAL REGRESSION WITH PROXIES: A SEMI-PARAMETRIC METHOD
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This study investigates asset returns within the Iraq Stock Exchange by employing both the Fama-MacBeth regression model and the Fama-French three-factor model. The research involves the estimation of cross-sectional regressions wherein model parameters are subject to temporal variation, and the independent variables function as proxies. The dataset comprises information from the first quarter of 2010 to the first quarter of 2024, encompassing 22 publicly listed companies across six industrial sectors. The study explores methodological advancements through the application of the Single Index Model (SIM) and Kernel Weighted Regression (KWR) in both time series and cross-sectional analyses. The SIM outperformed the K

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Publication Date
Thu Jan 31 2019
Journal Name
Journal Of The College Of Education For Women
Polygamy in light of societal changes in Iraq (A Field Study in Baghdad)
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The polygamy as a social was known before Islam, has kept Islam on this system after it organized and put his controls and conditions, as justice between wives and the ability to alimony, it was not the purpose of satisfying the instinct of man and enjoyment, but his goal nominal than that, because it addresses problems humanity has goals noble, so the pluralism overlap of the fabric of families belonging to governance and benefits for women and men and society, which leads to increased ties of love between people of the same society and thus increases the cohesion and importance of the topic and its association with financial conditions have emerged as needed so you viewed in the second scientific Conference of the Department social Ser

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Publication Date
Tue Jun 01 2021
Journal Name
Political Sciences Journal
The role of elections in solidifying the process of democratization: a case study of Tunisian elections in 2019
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The electoral mechanism is remarkably clear, a political tool for institutional construction, directing political life, forming the political scene, and forming the partisan scene. This process was through the design of electoral laws, as elections in Tunisian political history represented the indicator of its slow and accelerated transformations, so The elections in Tunisia usually coincide with important political stages, accompanied by legislative or constitutional amendments in general, Islamic or secular forces have played a fundamental role in promoting the democratic experience and the principle of the peaceful transfer of power. This led to the formation of a national consensus that would help the country not enter into political

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Publication Date
Tue Dec 31 2019
Journal Name
Biochemical & Cellular Archives
8-HYDROXY-2-DEOXY GUANOSINE IS A NOVEL NEW BIOCHEMICAL MARKER FOR PATIENTS WITH MULTIPLE SCLEROSIS AND CORRELATION WITH PARAOXANASE-1 AND MDA
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Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of central nervous system with complex etiopathogenesis that impacts young adults (Lee et al., 2015), and MS impacts younger and middle aged character and leads to a range of disabilities that can alter their daily routines (Yara et al, 2010). Although, the exact cause of MS is still undetermined, the disease is mediated by adaptive immunity through the infiltration of T cells into the central nervous system (Bjelobaba et al, 2017). MS causes the Focal neurological symptomsand biochemical changes in the molecular level and the variation of neural cells such as loss or alteration of sensation, motor function, visible signs such as blurred vision or transient blindness,

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Publication Date
Sat Jan 01 2022
Journal Name
Aip Conference Proceedings
Theoretical calculation of the electronic current at N3 contact with TiO2 solar cell devices
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In this study, a theoretical scenario has been used to calculate the electronic current in sensitizer N3 molecule contact to TiO2 semiconductor for electrons in functional solar cells. It is known to play an important role on the compute the eficiency of solar cell. Some parameters of electronic current such as the transition energy, driving force energy, barrier height coupling overlapping values are determined. Transition energy is a necessary parameter to calculate the electronic current in solar cell with using wide polarity solvents Acetic acid, 2-Methoxyethanol, 1-Butanol, Methyl alcohol, chloroform, N,N-Dimethylacetamide and Ethyl alcohol via the quantum donor-acceptor system. Here, we show the results of transition energy can be var

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Publication Date
Sun Apr 01 2007
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Observations on the ultrastructure of a rat mammary gland treated with harmal and borage
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Background : It had been indentified by histological, histochemical and morphometrical studies that peganum harmala is a mammogenic herb and borage officinalis is a lactogenic one . To complete our investigation about these two herbs , we performed electron microscopical study . Materials and methods : Rats were grouped according to their physiological status into three groups . Each group was subdivided in to three subgroups : one control and two experimental . The two experimental group were treated daily; the 1st one with an aqueous extract of peganum harmala seeds and the 2nd with an aqueous extract of borage officinalis flowers . After two weeks of treatment , mammary glands were employed for electron microscopical study . Resu

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Publication Date
Sun Apr 06 2008
Journal Name
Diyala Journal For Pure Science
Preliminary Test Bayesian –Shrunken Estimators for the Mean of Normal Distribution with Known Variance
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Publication Date
Wed Jan 01 2020
Journal Name
Materials Science And Engineering
Fresh and Hardened Properties of Nano Self-Compacting Concrete with Micro and Nano Silica
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Abstract<p>Self-compacting concrete (SCC) has undergone a remarkable evolution recently based on the results from several studies that have indicated the chain of benefits SCC provides. Micro and nano materials used as mineral additives in SCC offer several high-performance properties, and this research studies the effects of micro silica (MS) (10%, used as a reference) and colloidal nano-silica (CNS) (2.5%, 5%, 7.5%, and 10%) on the fresh and hardened properties of SCC. All mixtures were estimated using flow, L-box, and V-funnel tests to examine workability and compressive strength, modulus of elasticity and tensile strength as hardened properties. The use of CNS increased the overall compressi</p> ... Show More
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Publication Date
Wed Jul 08 2015
Journal Name
The Iraqi Postgraduate Medical Journal
Simultaneous Complete Intracorneal Ring Implantation with Intrapocket Collagen Cross- Linking for Treatment of Keratoconus
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BACKGROUND: Keratoconus is a progressive non inflammatory bilateral (usually asymmetric) ectatic corneal disease characterized by paraxial stromal thinning ,weakening that lead to corneal surface distortion ,vision loss primarily from irregular astigmatism and myopia and secondly from corneal scar. OBJECTIVE: To evaluate visual and refractive outcomes after intracorneal continuous ring (ICCR) implantation combined with intrapocket corneal collagen cross linking in patient with keratoconus. Setting: Eye Specialty Private Hospital, Baghdad, Iraq. METHODS: This study assessed the results of implantation of Myoring ICCR combined with CXL in 40 eyes with KC. Outcome measures include UDVA,CDVA(spectacle correction),refraction, complications and s

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Publication Date
Wed Jul 01 2020
Journal Name
Iop Conf. Series: Materials Science And Engineering
Structural Performance of Slender RC Columns with Cross and Square-Shaped under Compression Load
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Abstract<p>The idea of using slender Reinforced Concrete (RC) columns with cross-shaped (+-shaped) instead of columns with square-shaped was discussed in this paper. The use of +-shaped columns provides many architectural and structural advantages, such as avoiding prominent columns edges and improved the structural response of member. Therefore, this study explores the structural response of slender +-shaped columns experimentally and numerically by nonlinear finite element analysis using Abaqus simulation tools. The results showed an excellent convergence in strength between numerical and test results with an average standard deviation of 0.05 and 0.07. Besides that, the use of +-shaped column</p> ... Show More
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