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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
Tue Mar 01 2022
Journal Name
Journal Of Osseointegration & Oral Rehablitation
Evaluation of marginal bone loss around SLActive implants by CBCT using different implant dimensions and surgical approaches: A clinical and radiological prospective study
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Aim: The reduction in the amount of marginal bone is the most important demand for the long term success of dental implants. This prospective clinical study was aimed to investigate the marginal bone loss of early loaded SLActive implants with different dimensions and surgical approaches. Materials and methods Fifteen patients aged from 18 to 60 years were divided into 2 groups (flapped and flapless approach) that underwent delayed implant placement protocol with SLActive implants. The marginal bone level was estimated by cone-beam computed tomography during three different periods: preoperatively, 8 weeks after surgery and 24 weeks after loading of the prosthesis. Results: The mean value of marginal bone level was not significantly chan

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Publication Date
Wed Jan 01 2020
Journal Name
Ieee Access
Smart Routing Management Framework Exploiting Dynamic Data Resources of Cross-Layer Design and Machine Learning Approaches for Mobile Cognitive Radio Networks: A Survey
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Publication Date
Mon Oct 27 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Occlusal features, perception of occlusion and orthodontic treatment need and demand among 13 years aged Baghdadi students Part II: (Cross sectional epidemiological study)
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Background: The present study aimed to assess the distribution, prevalence, severity of malocclusion in Baghdad governorate in relation to gender and residency Materials and Methods: A multi-stage stratified sampling technique was used in this investigation to make the sample a representative of target population. The sample consisted of 2700 (1349 males and 1351 females) intermediate school students aged 13 years representing 3% of the total target population. A questionnaire was used to determine the perception of occlusion and orthodontic treatment demand of the students and the assessment procedures for occlusal features by direct intraoral measurement using veriner and an instrument to measure the rotated and displaced teeth. Results a

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Publication Date
Sun Jan 17 2021
Journal Name
Academic Journal Of Interdisciplinary Studies
Employees Retention Strategy and its Impact on Organizational Memory: An Exploratory Research for the opinion of Faculty Members at Private Colleges on Baghdad
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The research aims to determine the impact of employees’ retention strategy on organizational memory. This research is historical, descriptive, and analytical. The sample consists of 158 faculty members in five private colleges in Baghdad. The technique used to analyze the data is SEM (Structural Equation Modeling), and SPSS (Statistical Package for the Social Sciences). The research concludes that the employees retaining strategy plays a vital role in retaining employees and hence maintains organizational memory. The findings and recommendations of this research assure the administrations of private colleges that employees retention strategy play a vital role in retaining its employee and hence maintains organizational memory. T

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Publication Date
Thu Jan 01 2009
Journal Name
Ibn Al-haitham Journal For Pure And Applied Science
Complexeation Behavior of CoII, NiII, CuII, ZnII, and CdII Ions Toward Schiff Base Derived From 2, 4-Dihydroxy Benzaldehyde and O-Phenylene Diamin
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The aim of this work covers the synthesis and characterization of the new tertra dentate ligand (H4L) containing (N and O) as donor set atoms kind (N2O2) where: H4L=Bis-1,2 (2,4- dihydroxybenzylediene phylinediamine . The preparation of ligand contains reaction 2, 4 - Dihydroxy benzaldehyde and o-phenylene diamine . Schiff base was reacted with some metal ions in the presence of methanol to give the complexes in the general formula [M (H2L)] where: MII = Co, Ni, Cu, Zn, Cd. All compounds were characterized by spectroscopic methods I.R , U.V.-Vis, metal content and molar conductivity measurements, showed that the complexes are non-electrolyte. The proposed geometry for all of the proposed complexes was a tetrahedral while Ni complex was squa

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Publication Date
Fri Jan 01 2021
Journal Name
Indonesian Journal Of Electrical Engineering And Computer Science
BotDetectorFW: an optimized botnet detection framework based on five features-distance measures supported by comparisons of four machine learning classifiers using CICIDS2017 dataset
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<p><span>A Botnet is one of many attacks that can execute malicious tasks and develop continuously. Therefore, current research introduces a comparison framework, called BotDetectorFW, with classification and complexity improvements for the detection of Botnet attack using CICIDS2017 dataset. It is a free online dataset consist of several attacks with high-dimensions features. The process of feature selection is a significant step to obtain the least features by eliminating irrelated features and consequently reduces the detection time. This process implemented inside BotDetectorFW using two steps; data clustering and five distance measure formulas (cosine, dice, driver &amp; kroeber, overlap, and pearson correlation

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Publication Date
Sun Dec 09 2018
Journal Name
Baghdad Science Journal
Application of Randomly Amplified Polymorphic DNA (RAPD) Technique to Estimate Genetic Distance among Some Methicillin Resistant Staphylococcus aureus Isolated from Different Iraqi Hospitals
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Methicillin resistant Staphylococcus aureus (MRSA) is one of the principal nosocomial causative agents. This bacterium has the capability to resist wide range of antibiotics and it is responsible for many diseases like skin, nose and wounds infection. In this study, randomly amplified polymorphic DNA (RAPD)-PCR was applied with ten random primers to examine the molecular diversity among methicillin resistant Staphylococcus aureus (MRSA) isolates in the hospitals and to investigate the genetic distance between them. 90 Isolates were collected from clinical specimens from Iraqi hospitals for a total of 90 isolates. Only 10 strains (11.11%) were found to be MRSA. From these 10 primers, only 9 gave clear amplification products. 91 fragment l

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Publication Date
Thu Jun 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Measuring the continuity of the demand for money and its impact on the Iraqi dinar exchange rate for the period 1991-2013 function
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 Research Summary

It highlights the importance of assessing the demand for money function in Iraq through the understanding of the relationship between him and affecting the variables by searching the stability of this function and the extent of their influence in the Iraqi dinar exchange rate in order to know the amount of their contribution to the monetary policies of the Iraqi economy fee, as well as through study behavior of the demand for money function in Iraq and analyze the determinants of the demand for money for the period 1991-2013 and the impact of these determinants in the demand for money in Iraq.

And that the problem that we face is how to estimate the total demand for money in

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Publication Date
Sat Dec 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Comparison Between Ordinary Methods (LS,IV) and Robust Methods (2SWLS,LTS,RA) to estimate the Parameters of ARX(1,1,1) Model for Electric Loads
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Abstract:

The models of time series often suffer from the problem of the existence of outliers ​​that accompany the data collection process for many reasons, their existence may have a significant impact on the estimation of the parameters of the studied model. Access to highly efficient estimators  is one of the most important stages of statistical analysis, And it is therefore important to choose the appropriate methods to obtain good  estimators. The aim of this research is to compare the ordinary estimators and the robust estimators of the estimation of the parameters of

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Publication Date
Sat Jan 01 2022
Journal Name
Ssrn Electronic Journal
Developing a Predictive Model and Multi-Objective Optimization of a Photovoltaic/Thermal System Based on Energy and Exergy Analysis Using Response Surface Methodology
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