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Free Convective Heat Transfer with Different Sections Lengths Placed at the Exit of a Vertical Circular Tube subjected to a Constant Heat Flux
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A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of 600 mm (L/D=20), 900 mm (L/D=30), 1200 mm (L/D=40), 1500 mm (L/D=50), and 1800 mm (L/D=60). It was found that the surface temperature along the tube axial distance would be higher for restriction with length of 1800 mm (L/D=60) and it would be smaller for the restriction with length of 1200 mm (L/D=40). The results show that the local Nux and average Nusselt number were higher values for the restriction with length of 1200 mm (L/D=40) and smaller values for the restriction with length of 1800 mm (L/D=60). The results were correlated with empirical equations and presented as Logagainst Log for each case investigated and a general empirical equation was proposed for all cases.

 

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Publication Date
Wed Jun 01 2022
Journal Name
Baghdad Science Journal
Constructing a Software Tool for Detecting Face Mask-wearing by Machine Learning
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       In the pandemic era of COVID19, software engineering and artificial intelligence tools played a major role in monitoring, managing, and predicting the spread of the virus. According to reports released by the World Health Organization, all attempts to prevent any form of infection are highly recommended among people. One side of avoiding infection is requiring people to wear face masks. The problem is that some people do not incline to wear a face mask, and guiding them manually by police is not easy especially in a large or public area to avoid this infection. The purpose of this paper is to construct a software tool called Face Mask Detection (FMD) to detect any face that does not wear a mask in a specific

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Publication Date
Wed Sep 01 2021
Journal Name
Baghdad Science Journal
An Efficient Image Encryption Using a Dynamic, Nonlinear and Secret Diffusion Scheme
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The growing use of tele

This paper presents a new secret diffusion scheme called Round Key Permutation (RKP) based on the nonlinear, dynamic and pseudorandom permutation for encrypting images by block, since images are considered particular data because of their size and their information, which are two-dimensional nature and characterized by high redundancy and strong correlation. Firstly, the permutation table is calculated according to the master key and sub-keys. Secondly, scrambling pixels for each block to be encrypted will be done according the permutation table. Thereafter the AES encryption algorithm is used in the proposed cryptosystem by replacing the linear permutation of ShiftRows step with the nonlinear and secret pe

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Publication Date
Thu Dec 31 2015
Journal Name
Al-khwarizmi Engineering Journal
Experimental Study on the Effect of Insertion of Copper Lessing Rings in Phase Change Material (PCM) on the Performance of Thermal Energy Storage Unit
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Abstract

One of the most suitable materials to be used in latent heat thermal energy storage system (LHTES) are Phase change materials, but a problem of slow melting and solidification processes made many researchers focusing on how to improve their thermal properties. This experimental work concerned with the enhancing of thermal conductivity of phase change material. The enhancing method was by the addition of copper Lessing rings in phase change material (paraffin wax). The effect of diameter for the used rings was studied by using two different diameters (0.5 cm and 1cm). Also, three volumetric percentages of rings addition (3%, 6% and 10%) were tested for each diameter. The discharging process was done with

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Publication Date
Mon Sep 23 2019
Journal Name
Baghdad Science Journal
A Semi-Supervised Machine Learning Approach Using K-Means Algorithm to Prevent Burst Header Packet Flooding Attack in Optical Burst Switching Network
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Optical burst switching (OBS) network is a new generation optical communication technology. In an OBS network, an edge node first sends a control packet, called burst header packet (BHP) which reserves the necessary resources for the upcoming data burst (DB). Once the reservation is complete, the DB starts travelling to its destination through the reserved path. A notable attack on OBS network is BHP flooding attack where an edge node sends BHPs to reserve resources, but never actually sends the associated DB. As a result the reserved resources are wasted and when this happen in sufficiently large scale, a denial of service (DoS) may take place. In this study, we propose a semi-supervised machine learning approach using k-means algorithm

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Publication Date
Tue May 19 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Effect of poly propylene fibers incorporation and their oxygen plasma treatment on tensile strength, wettability and wear resistance of heat cure denture base acrylic resin
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Background: Recently, Poly propylene fibers with and without plasma treatment have been used to reinforce heat cure denture base acrylic but, so far some of properties like tensile strength , wettability and wear resistance not evaluated yet, the aim of the study is to clarify the influence of incorporation of treated and untreated fibers on these properties. Materials and methods: Twenty one specimens were fabricated for every tested property(tensile strength, wear resistance and wettability) that classified into three groups(control, untreated poly propylene fibers reinforced specimens and Oxygen plasma treated group)and for each test sevens amples were used(n=7). Tensile strength was tested using Instron universal testing machine, wear

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Publication Date
Tue May 19 2026
Journal Name
Al–bahith Al–a'alami
Media separation: The Relationship of Arab Immigrants with the Media of the Countries of Diaspora (Sweden as a model) (A Research Derived from PhD Dissertation)
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The research seeks to study the subject (Media separation: the Relationship of Arab Immigrants with the Media of the Countries of Diaspora/ Sweden as a model). Where this phenomenon, "problem" has not been subjected to an in-depth study to find out the causes of this media separation and its repercussions on the immigrant, whether in the problem of integration, or his opportunity to work, or adapt to live in the new society.

Separation is a kind of word that is rarely used in Arabic media studies, relevant, sometimes, to the meaning of “refraining from watching TV or listening to the radio or reading newspapers”. Sometimes, it means “not tuning to or using any form of media like radios or newspapers to be updated about what

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Publication Date
Fri Mar 01 2019
Journal Name
Al-khwarizmi Engineering Journal
A Digital-Based Optimal AVR Design of Synchronous Generator Exciter Using LQR Technique
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In this paper a new structure for the AVR of the power system exciter is proposed and designed using digital-based LQR. With two weighting matrices R and Q,  this method produces an optimal regulator that is used to generate the feedback control law. These matrices are called state and control weighting matrices and are used to balance between the relative importance of the input and the states in the cost function that is being optimized. A sample power system composed of single machine connected to an infinite- bus bar (SMIB) with both a conventional and a proposed Digital AVR (DAVR) is simulated. Evaluation results show that the DAVR damps well the oscillations of the terminal voltage and presents a faster respo

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Publication Date
Wed Mar 02 2022
Journal Name
Journal Of Educational And Psychological Researches
A Suggested Conception to Employ Gamificatio in Teaching the General Education Curricula
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The study aimed to build a suggested conception for employing gamification in teaching the general education curricula. Using the analytical method of the previous analytical studies in Teaching, which agreed with the determinants of the analysis of 20 studies from 2014 to 2019, they come on order: points, badges, leaderboards, and then levels. The four most commonly used theories are the theory of self-determination, flow theory, the theory of planned behavior and social theory. In addition, the researcher identified the most commonly used models in gamification, respectively: the ARCS model and the user-based design model. Based on the results of the analysis and using the descriptive approach, the researcher presented a practical perc

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Publication Date
Tue Jan 01 2019
Journal Name
Journal Of The College Of Languages (jcl)
To Shape a Silence While Breaking it: Toni Morrison’s the Bluest Eye
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Toni Morrison (1931-), the first African-American winner of Noble Prize in literature (1993) and the winner of the 1988 Pulitzer Prize for fiction, regards herself as the historian of African-American people. She does not think of her writings as literature but as a sacred book dedicated to explore the interior lives of blacks. She creates history by disregarding European standards and the white man's view of African- Americans. She adopts her people's point of view, invests their heritage, voices their pains and uses their vernacular. She even writes to a black audience. She establishes the black novel  by depicting the blackness of American literature. In choos

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Publication Date
Mon Mar 01 2021
Journal Name
مجلة العلوم القانونية
أساس انتقال المخاطر في عقود التجارة الدولية
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أساس انتقال المخاطر في عقود التجارة الدولية