Preferred Language
Articles
/
joe-110
A Laboratory Study Attempt of Flow and Energy Dissipation in Stepped Spillways
...Show More Authors

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.

 

View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Mar 17 2019
Journal Name
Baghdad Science Journal
Studying the Flux Density of Bright Active Galaxies at Different Spectral Bands
...Show More Authors

Statistical studies are reported in this article for an active galactic nuclei sample of different type of active galaxies Seyferts 1, Seyferts 2, and Quasars. These sources have been selected from a Catalogue for bright X-ray galaxies. The name of this index is ROSAT Bright Source Catalogue (RBSC) and the NRAO VLA Sky Survey (NVSS). In this research, multi-wavelength observational bands Radio at 1.4 GHz, Optical at 4400 A0, and X-ray at energy 0.1-2.4 KeV have been adopted in this study. The behavior of flux density ratios has been studied ,  with respect to the absolute magnitude . Furthermore, the Seyfert1 and Seyfert 2 objects are combined in one group and the QSOs are collectest in another group. Also, it has been fo

... Show More
View Publication Preview PDF
Scopus (14)
Scopus Clarivate Crossref
Publication Date
Sun Sep 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
The Use of Replacement Models On Determine the Optimal Time to Replacement
...Show More Authors

Abstract:-

            The approach maintenance and replacement one of techniques of operations research whom cares of the failure experienced by a lot of production lines which consist of a set of machines and equipment, which in turn exposed to the failure or work stoppages over the lifetime, which requires reducing the working time of these machines or equipment below what can or conuct  maintenance process once in a while or a replacement for one part of the machine or replace one of the machines in production lines. In this research is the study of the failure s that occur in some parts of one of the machines for the General Company for Vege

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Dec 18 2017
Journal Name
Al-khwarizmi Engineering Journal
Path Planning of an autonomous Mobile Robot using Swarm Based Optimization Techniques
...Show More Authors

This paper presents a meta-heuristic swarm based optimization technique for solving robot path planning. The natural activities of actual ants inspire which named Ant Colony Optimization. (ACO) has been proposed in this work to find the shortest and safest path for a mobile robot in different static environments with different complexities. A nonzero size for the mobile robot has been considered in the project by taking a tolerance around the obstacle to account for the actual size of the mobile robot. A new concept was added to standard Ant Colony Optimization (ACO) for further modifications. Simulations results, which carried out using MATLAB 2015(a) environment, prove that the suggested algorithm outperforms the standard version of AC

... Show More
View Publication Preview PDF
Crossref (22)
Crossref
Publication Date
Wed Dec 13 2017
Journal Name
Al-khwarizmi Engineering Journal
Multi-Dimensional Angle of Arrival Estimation by Circular Phased Adaptive Array Antennas
...Show More Authors

In this paper the use of a circular array antenna with adaptive system in conjunction with modified Linearly Constrained Minimum Variance Beam forming (LCMVB) algorithm is proposed to meet the requirement of Angle of Arrival (AOA) estimation in 2-D as well as the Signal to Noise Ratio (SNR) of estimated sources (Three Dimensional 3-D estimation), rather than interference cancelation as it is used for. The proposed system was simulated, tested and compared with the modified Multiple Signal Classification (MUSIC) technique for 2-D estimation. The results show the system has exhibited astonishing results for simultaneously estimating 3-D parameters with accuracy approximately equivalent to the MUSIC technique (for estimating elevation and a

... Show More
View Publication Preview PDF
Publication Date
Tue May 01 2018
Journal Name
Journal Of Physics: Conference Series
Producing High Purity of Metal Oxide Nano Structural Using Simple Chemical Method
...Show More Authors

View Publication
Scopus (12)
Crossref (10)
Scopus Clarivate Crossref
Publication Date
Wed Jan 01 2020
Journal Name
Journal Of Human Sport And Exercise - 2020 - Winter Conferences Of Sports Science
Test design to measure the cognitive processing speed of table tennis players
...Show More Authors

Table tennis is considered one of the fast base sports that the player needs to have the speed of performance and awareness, especially in straight forward and back strikes, which is an important offensive skills, and the player success depends on his perception speed to the point of the fall of the ball in the arena of his competitor. But there is no way to measure cognitive processing speed. Therefore, the researchers sought to design a test that measures this ability to ensure its scientific evaluation, and then establish standard scores for this test for the players of the specialized school of table tennis, to help evaluate them objectively and move away from subjective estimates when evaluating and developing measuring instruments in

... Show More
View Publication Preview PDF
Scopus (5)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Sat Oct 01 2016
Journal Name
Journal Of Engineering
Improvement of Asphalt Concrete Mixtures by Adding Pulverised Fuel Ash as Filler
...Show More Authors

Consuming of by-product or waste materials in highway engineering is significant in the construction of new roads and/or in renovations of the existing ones. Pulverised Fuel ash (PFA), which is a by-product material of burning coal in power stations, is one of these materials that might be incorporated instead of mineral filler in hot asphalt mixtures.

Two types of surface course mixtures have been prepared one with conventional mineral filler i.e. ordinary Portland cement (OPC) while the second was with PFA. Several testings have been conducted to indicate the mechanical properties which were Marshall Stability and Indirect Tensile Strength tests. On the other hand, moisture damage and ageing have been evaluated

... Show More
View Publication Preview PDF
Publication Date
Wed Nov 01 2023
Journal Name
Iop Conference Series: Earth And Environmental Science
Two New Records of Cerceris Latreille, 1802 (Hymenoptera: Apoidea: Crabronidae) from Iraq
...Show More Authors
Abstract<p>In a survey of the crabronid fauna of Iraq during June to October 2022; 9species belonging to the genus <italic>Cerceris</italic> Latreille, 1802 were identified. Twospecies are new record of the fauna of Iraq: <italic>C. dorsalis</italic> Eversmann, 1849 and <italic>C. priesneri</italic> Mochi, 1939. Brief description, diagnostic characters, some collecting information, and photographs of each species are provided. As well provides a key to the species depending on many morphological features especially: propodeal enclosure, semicircular plate at base of second gastral sternites and free margin of clypeus. Moreover, this study observed that most collecte</p> ... Show More
View Publication
Scopus (1)
Scopus Crossref
Publication Date
Thu Nov 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Using Multidimensional Contingency Coefficient to Discrimination Arabic Poems for Sample of Poets
...Show More Authors

The purpose of this paper to discriminate between the poetic poems of each poet depending on the characteristics and attribute of the Arabic letters. Four categories used for the Arabic letters, letters frequency have been included in a multidimensional contingency table and each dimension has two or more levels, then contingency coefficient calculated.

The paper sample consists of six poets from different historical ages, and each poet has five poems. The method was programmed using the MATLAB program, the efficiency of the proposed method is 53% for the whole sample, and between 90% and 95% for each poet's poems.

 

View Publication Preview PDF
Crossref
Publication Date
Fri Dec 01 2017
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
COLOR VARIATION OF STREPTOPELIA DECAOCTO (AVIS, COLUMBIDAE) WITH SOME NOTES ON ENDOPARASITES
...Show More Authors

The present paper includes a study of color variation in Iraqi Collared dove Streptopelia decaocto. Three different populations have been recognized: the southern population which belongs to the Indian race, the northern population to the Eurasian race; the dark and light color variation occurs in the Baghdad population because of hybridisation between the two races, found infected with two cestodes,  Raillietina echinobothrida found  in most of our specimens, while the dark face found beside R. echinobothrida infected with Idiogenes sp. getting it probably from vertebrate sources. We believe that most of the Baghdad population was intermediate between north and south races.

... Show More
View Publication Preview PDF
Scopus Crossref