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Estimation of Volumetric Mass Transfer Coefficient in Bioreactor
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This study is concentrated to investigate the effects of aeration and stirring speed on the volumetric mass transfer coefficient (KLa). A dynamic technique was used in estimating KLa values in order to achieve the aim of this study.

This study was done in 10L bioreactor by using two medias:-

  1. Dionized water
  2. Xanthan solution (1 g /L)

Moreover, the research covered a comparison between the obtained values of KLa.

The Xanthan solution was used because of its higher viscosity in comparison with water. It behaves similarly to the cultivation medium when organisms are cultivated in a bioreactor. Growth of organisms in the reactor leads to a change in the viscosity of the medium which affects the mass transfer.

Two variables, the effect of air flow rate (3-20 L/min) and the effect of stirring speed (250-700rpm) on KLa value were studied. Other parameters such as temperature, liquid volume, and stirrer shape and stirrer position were held constant; the results demonstrated an increase in KLa – value and mass transfer with increasing stirrer speed. Thus at higher speed, better dispersion of the bubbles was obtained. Therefore, that increased the surface / volume ratio which increased the mass transfer area i.e. KLa value.

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Publication Date
Thu Jul 01 2021
Journal Name
Journal Of Physics: Conference Series
Estimation of the reliability function of the Rayleigh distribution using some robust and kernel methods
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Abstract<p>The research presents the reliability. It is defined as the probability of accomplishing any part of the system within a specified time and under the same circumstances. On the theoretical side, the reliability, the reliability function, and the cumulative function of failure are studied within the one-parameter Raleigh distribution. This research aims to discover many factors that are missed the reliability evaluation which causes constant interruptions of the machines in addition to the problems of data. The problem of the research is that there are many methods for estimating the reliability function but no one has suitable qualifications for most of these methods in the data such </p> ... Show More
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Publication Date
Fri Mar 30 2012
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Numerical Analysis of Laminar Natural Convection in Square Enclosure with and without Partitions and Study Effect of pPartition on the Flow Pattern and Heat Transfer
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The problem of steady, laminar, natural convective flow in an square enclosure with and without partitions is considered for Rayleigh number (103-106) and Prandtl number (0.7). Vertical walls were maintained isothermal at different temperatures while horizontal walls and the partitions were insulated. The length of partition was taken constant. The number of partitions were placed on horizontal surface in staggered arrangement from (1– 3) and ratio of partition thickness (H/L= 0.033, 0.083, 0.124). The problem is formulated in terms of the vorticity-stream function procedure. A numerical solution based on a program in Fortran 90 with the finite difference method is obtained. Representative results illustrating the effects of the thickn

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Publication Date
Tue Jan 01 2019
Journal Name
Baghdad Science Journal
Hazard Rate Estimation Using Varying Kernel Function for Censored Data Type I Article Sidebar
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n this research, several estimators concerning the estimation are introduced. These estimators are closely related to the hazard function by using one of the nonparametric methods namely the kernel function for censored data type with varying bandwidth and kernel boundary. Two types of bandwidth are used: local bandwidth and global bandwidth. Moreover, four types of boundary kernel are used namely: Rectangle, Epanechnikov, Biquadratic and Triquadratic and the proposed function was employed with all kernel functions. Two different simulation techniques are also used for two experiments to compare these estimators. In most of the cases, the results have proved that the local bandwidth is the best for all the types of the kernel boundary func

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Publication Date
Thu Jan 22 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation the effect of nano-fillers (TiO2, AL2O3, SiO2) addition on glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material
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Background: The PMMA polymer denture base materials are low in thermal and strength properties. The aim of the study was to investigate the change in glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material by addition of Al2O3, TiO2 and SiO2nano-fillers in 5% by weight. Materials and methods: The type of polymerization is free radical bulk polymerization. one hundred twenty (120) specimens were prepared , the specimens were divided into four groups according to the material had been added (one control and three for Al2O3, TiO2 and SiO2nanocomposite) each group was subdivided in to three groups according to the test had been done on it, the degree of transition (Tg) was measured by The d

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Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
The role of administrative supervision scope and the single window to increase the efficiency of investment (Case study: Sudanese Ministry of Investment)
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Investment drives the wheel of the development of different developed and developing countries. Sudan is a model for a developing country facing a lot of difficulties in the field of both local and foreign investment. The present study was focused on the problem of poor diversification and efficiency of both local and foreign investment in Sudan. Also, it clarified the important role of administrative supervision to strengthen the efficiency of investment, taking the experience of the Sudan as a model. The researchers used the well-known descriptive and analytical tools (questionnaire, interview, observation) to complete this study. A well designed questionnaire was used. It included all questions that could cover all aspects of

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Publication Date
Sat Jun 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Impact of the global financial crisis on the efficiency of activity of the Iraqi Stock Market, "An Empirical Study for the period 2006-2008”
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Abstract
  financial market occupy very important place in the economic activity all over the world countris, and its importance increased with considerable technological progress in the world of transportation ,communications and information where its impact have spread over the whole world, which led to link the international economy in a kind of international relations so that the open policy became the prevailing trend in national and regional economies within the framework of the new world order.

the international economy has faced the financial crisis, global, that hit all world economies although the United States is the center of the crisis and the starting spark for it w

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Publication Date
Sun Jan 01 2023
Journal Name
International Journal Of Environmental Science And Development
Estimation of the Concentrations of Some Pollutants Resulting from the Use of Arabian Bakhour and Their Effect in Patients with Asthma in the City of Baghdad
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This research focus on studying 3 types of Bakhour in the markets of Baghdad city and assessing their impact on the quality of life for asthmatic whom used Bakhour at their houses through investigating particles physical properties, also estimating the levels of heavy metals (Cd, Cu, Mn, Pb and Zn), Particulate Matter PM2.5, PM10, Total Volatile Organic Compounds (TVOC) and formaldehyde (HCHO). The quality of life for asthmatic patients whom use Bakhour was assessing by Mini Asthma Quality of Life Questionnaire. The results indicated that shapes of Bakhour particles were irregular or spherical. Burning process generated the higher percent of PM ˂1μm. Type 2 Bakhour showed the highest percent of <1μm which was 73%.The amount of

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Publication Date
Mon Sep 23 2019
Journal Name
Baghdad Science Journal
Hazard Rate Estimation Using Varying Kernel Function for Censored Data Type I
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     In this research, several estimators concerning the estimation are introduced. These estimators are closely related to the hazard function by using one of the nonparametric methods namely the kernel function for censored data type with varying bandwidth and kernel boundary. Two types of bandwidth are used:  local bandwidth and global bandwidth. Moreover, four types of boundary kernel are used namely: Rectangle, Epanechnikov, Biquadratic and Triquadratic and the proposed function was employed with all kernel functions. Two different simulation techniques are also used for two experiments to compare these estimators. In most of the cases, the results have proved that the local bandwidth is the best for all the

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Publication Date
Sun Oct 10 2021
Journal Name
Journal Of Physics
A novel kite cross hexagonal search algorithm for fast block motion estimation
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The performance quality and searching speed of Block Matching (BM) algorithm are affected by shapes and sizes of the search patterns used in the algorithm. In this paper, Kite Cross Hexagonal Search (KCHS) is proposed. This algorithm uses different search patterns (kite, cross, and hexagonal) to search for the best Motion Vector (MV). In first step, KCHS uses cross search pattern. In second step, it uses one of kite search patterns (up, down, left, or right depending on the first step). In subsequent steps, it uses large/small Hexagonal Search (HS) patterns. This new algorithm is compared with several known fast block matching algorithms. Comparisons are based on search points and Peak Signal to Noise Ratio (PSNR). According to resul

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Publication Date
Sun Oct 01 2017
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Pre-operative serum TSH level estimation for predicting malignant nodular thyroid disease
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