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A Laboratory Study Attempt of Flow and Energy Dissipation in Stepped Spillways
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A new laboratory study conducted on stepped spillways in order to investigate their efficiency of dissipating flow energy. All previous study on stepped spillway indicated that the flow energy dissipation decreased as increasing in discharge. Increasing in the step numbers and the spillway slope led to energy dissipation decrease. In this study, an experimental attempt to increase energy dissipation at variable discharges was performed on stepped spillway and that leads to decreasing the cost of initiating the stilling basin or may be ignoring it. Five spillways were constructed from concrete and tested to investigate and compare among them. Three were roughed by gravel with different size for each one, one of them was stepped without any addition, and the last one was stepped with cavitation. The height of stepped spillways was 18 cm with unique numbers of steps (n = 3), and unique downstream slope of stepped face (θ =30⁰) were utilized. The percentage of relative energy dissipation (R.E.D) was increased using rough surface with coarse gravel. When the size of gravel increased, the R.E.D was increased and when using the ratio between heights of gravel to steps of 0.5, the R.E.D was increased to about triple compared with traditional spillways. The R.E.D was decreased when the cavitation on the stepped surface was utilized compared to the stepped spillway without any addition for large discharges and that was inverse for small discharges. Comparing to steps without any addition, the rouged steps with the larger size of gravel maximized the energy dissipation for both small and large discharges. The relative energy dissipation was 26.73 % compared with traditional spillway and 16.73 % compared with stepped spillway without any addition, since the stepped spillways more effective than traditional spillways by 10 %. In general, the R.E.D was decreased when increasing the discharge.

 

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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
Disjuncts and Conjuncts: A Syntactic Type of Study to Evaluate Kurdish Students' Writing in English (At University Level)
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The principal concern of this study is Disjunct and Conjunct adverbials in the
English language. The study sets out to explore and clarify the types, nature and
structure of disjuncts and conjuncts. It also aims at testing student's performance to
evaluate the use and usage of the disjuncts and conjuncts in their written performance.
Two tests, accordingly, were given to some fifty students of at the Dept. of English, at
the college of languages (third and fourth stages) in the University of Sulaimani. The
hypothesis that the study was based on are those students use disjuncts and conjuncts
hardly enough in their writings and when doing so, they generally tend to stick only to
the most commonly used and familiar o

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Publication Date
Mon Dec 18 2017
Journal Name
Al-khwarizmi Engineering Journal
Experimental Study of Mixed Convection in an Enclosure with a Cold Movable Top Wall and Hot Bottom Wall
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Mixed convection heat transfer to air inside an enclosure is investigated experimentally. The bottom wall of the enclosure is maintained at higher temperature than that of the top wall which keeps in oscillation motion, whereas the left and right walls are well insulated. The differential temperature of the bottom and top walls changed several times in order to accurately characterize the temperature distribution over a considerable range of Richardson number. Adjustable aspect ratio box was built as a test rig to determine the effects of Richardson number and aspect ratio on the flow behavior of the air inside the enclosure. The flow fields and the average Nusselt number profiles were presented in this wo

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Publication Date
Thu Jul 01 2021
Journal Name
Iraqi Journal Of Science
The Influence of NMI against Modularity in Community Detection Problem: A Case Study for Unsigned and Signed Networks
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Community detection is useful for better understanding the structure of complex networks. It aids in the extraction of the required information from such networks and has a vital role in different fields that range from healthcare to regional geography, economics, human interactions, and mobility. The method for detecting the structure of communities involves the partitioning of complex networks into groups of nodes, with extensive connections within community and sparse connections with other communities. In the literature, two main measures, namely the Modularity (Q) and Normalized Mutual Information (NMI) have been used for evaluating the validation and quality of the detected community structures. Although many optimization algo

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Publication Date
Tue Sep 01 2020
Journal Name
Al-nahrain Journal Of Science
Spectrophotometric Determination of Co(II) in Vitamin B12 Using2-(biphenyl-4-yl)-3-((2-(2,4-dinitrophenyl) hydrazono)methyl) imidazo [1,2-a]pyridine as Ligand by Flow Injection–Merging Zone Analysis
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Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Parametric Study of Active Solar Heating Using a Pebble Bed as a Thermal Collector and Storage Unit
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In this study, pebble bed as an absorber and storage material was placed in a south facing, flat plate air-type solar collector at fixed tilt angle of (45°). The effect of this material and differ- ent parameters on collector efficiency has been investigated experimentally and
theoretically. Two operation modes were employed to study the performance of the solar air heater. An inte- grated mode of continuous operation of the system during the period of (11:00 am – 3:00 pm) and non-integrated mode in which the system stored the solar energy through the day then used the stored energy during the period of (3:00 pm – 8:00 pm). The results of parametric study in case of continuous operating showed that the maximum average temperatur

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Publication Date
Tue Jan 02 2018
Journal Name
Arab Journal Of Basic And Applied Sciences
Daftardar-Jafari method for solving nonlinear thin film flow problem
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Publication Date
Fri Jan 01 2010
Journal Name
2010 Second International Conference On Computer Research And Development
Per-Priority Flow Control (PPFC) for Enhancing Metro Ethernet QoS
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Publication Date
Thu Oct 01 2020
Journal Name
International Journal Of Electrical And Computer Engineering (ijece)
Object tracking using motion flow projection for pan-tilt configuration
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We propose a new object tracking model for two degrees of freedom mechanism. Our model uses a reverse projection from a camera plane to a world plane. Here, the model takes advantage of optic flow technique by re-projecting the flow vectors from the image space into world space. A pan-tilt (PT) mounting system is used to verify the performance of our model and maintain the tracked object within a region of interest (ROI). This system contains two servo motors to enable a webcam rotating along PT axes. The PT rotation angles are estimated based on a rigid transformation of the the optic flow vectors in which an idealized translation matrix followed by two rotational matrices around PT axes are used. Our model was tested and evaluated

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Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Effective Computational Methods for Solving the Jeffery-Hamel Flow Problem
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In this paper, the effective computational method (ECM) based on the standard monomial polynomial has been implemented to solve the nonlinear Jeffery-Hamel flow problem. Moreover, novel effective computational methods have been developed and suggested in this study by suitable base functions, namely Chebyshev, Bernstein, Legendre, and Hermite polynomials. The utilization of the base functions converts the nonlinear problem to a nonlinear algebraic system of equations, which is then resolved using the Mathematica®12 program. The development of effective computational methods (D-ECM) has been applied to solve the nonlinear Jeffery-Hamel flow problem, then a comparison between the methods has been shown. Furthermore, the maximum

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Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Effective Computational Methods for Solving the Jeffery-Hamel Flow Problem
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في هذا البحث، تم تنفيذ الطريقة الحسابية الفعالة (ECM) المستندة إلى متعددة الحدود القياسية الأحادية لحل مشكلة تدفق جيفري-هامل غير الخطية. علاوة على ذلك، تم تطوير واقتراح الطرق الحسابية الفعالة الجديدة في هذه الدراسة من خلال وظائف أساسية مناسبة وهي متعددات الحدود تشيبشيف، بيرنشتاين، ليجندر، هيرمت. يؤدي استخدام الدوال الأساسية إلى تحويل المسألة غير الخطية إلى نظام جبري غير خطي من المعادلات، والذي يتم حله بع

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