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Comparative Study of Performance and Emission Characteristics between Spark Ignition Engine and Homogeneous Charge Compression Ignition Engine (HCCI)
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Many researchers consider Homogeneous Charge Compression Ignition (HCCI) engine mode as a promising alternative to combustion in Spark Ignition and Compression Ignition Engines. The HCCI engine runs on lean mixtures of fuel and air, and the combustion is produced from the fuel autoignition instead of ignited by a spark. This combustion mode was investigated in this paper. A variable compression ratio, spark ignition engine type TD110 was used in the experiments. The tested fuel was Iraqi conventional gasoline (ON=82).

The results showed that HCCI engine can run in very lean equivalence ratios. The brake specific fuel consumption was reduced about 28% compared with a spark ignition engine. The experimental tests showed that the emissions concentrations were reduced by 91.27% for NOx, 85.99% for CO, 78.91% for CO2, and 83.56% for unburned hydrocarbons compared to the SI engine. HCCI engine produced little noise with about 26.68% less than SI engine.

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Publication Date
Thu Feb 29 2024
Journal Name
Iraqi Journal Of Science
Monitoring the Expansion of Unplanned Urbanization and its Impact on Climate Change based on Google Earth Engine Service, a Case Study of Baghdad / Iraq
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     The earth's surface comprises different kinds of land cover, water resources, and soil, which create environmental factors for varied animals, plants, and humans. Knowing the significant effects of land cover is crucial for long-term development, climate change modeling, and preserving ecosystems. In this research, the Google Earth Engine platform and freely available Landsat imagery were used to investigate the impact of the expansion and degradation in urbanized areas, watersheds, and vegetative cover on the land surface temperature in Baghdad from 2004 to 2021. Land cover indices such as the Normalized Difference Vegetation Index, Normalized Difference Water Index, and Normalized Difference Built-up Index (NDVI, NDWI, an

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Publication Date
Wed Dec 29 2021
Journal Name
Al-khwarizmi Engineering Journal
Evaluation of the Main Causes of Diesel Engine Injector Failure using Fault Tree Analysis
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The maintenance of the diesel engine parts in any electric power station contains many problems that lead to stopping. Several reasons lead to such problems; these reasons should be analyzed and evaluated in order to eliminate their effects. This paper is based on evaluation of the main causes that lead to diesel engine injector failure as a main part of electric power stations, using fault tree analysis (FTA). The FTA is the most broadly utilized strategies in the industrial area to perform reliability analysis of complex designing frameworks. A fault tree is a logical representation of the relationship of basic events that lead to a given unwanted event (i.e., top event).

Starting with introducing the FTA and how it could be uti

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Publication Date
Thu Feb 07 2019
Journal Name
Iraqi Journal Of Laser
Gingival Enlargement Management using Diode Laser 940 nm and Conventional Scalpel Technique (A Comparative Study)
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Diode lasers are becoming popular in periodontal surgery due to their highly absorption by pigments such as melanin and hemoglobin their weak absorption by water and hydroxyapatite makes them safe to be used around dental hard tissues. Objective: The aim of the present study was to evaluate the efficiency of diode laser in performing gingivectomy in comparison to conventional scalpel technique in patients with chronic inflammatory enlargement. Materials and methods: Thirty patients were selected for this study. All of them required surgical treatment of gingival enlargements and were randomly divided into two groups: Control group (treated by scalpel and include sixteen patients) and study group (treated with diode laser 940nm and includ

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Publication Date
Mon Dec 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
A comparative study of stylistic kriging and Co - kriging Multivariate on the barley crop in Iraq
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  This paper deals  the prediction of the process of  random spatial data of two properties, the first is called  Primary variables  and the second is called secondary  variables ,   the method  that were used in the  prediction process for this type  of data is technique Co-kriging  , the method is usually used when the number of primary variables  meant to predict for one of its elements is measured in a particular location a few (because of the cost or difficulty of obtaining them) compare with secondary variable which is the number of elements  are available and  highly correlated with primary variables, as was the&nbs

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Publication Date
Sat Feb 09 2019
Journal Name
Journal Of The College Of Education For Women
A comparative Study to calculate the Runs Property in the encryption systems
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Cryptographic applications demand much more of a pseudo-random-sequence
generator than do most other applications. Cryptographic randomness does not mean just
statistical randomness, although that is part of it. For a sequence to be cryptographically
secure pseudo-random, it must be unpredictable.
The random sequences should satisfy the basic randomness postulates; one of them is
the run postulate (sequences of the same bit). These sequences should have about the same
number of ones and zeros, about half the runs should be of length one, one quarter of length
two, one eighth of length three, and so on.The distribution of run lengths for zeros and ones
should be the same. These properties can be measured determinis

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Publication Date
Tue Sep 28 2021
Journal Name
Journal Of The College Of Education For Women
Reasons for Lying in Kindergarten Children from the Kindergarten Teachers’ Point of View: A Comparative Study between Males and Females: سجلاء فائق هاشم , كلثوم عبد عون ردام
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Lying is considered a dangerous tendency among children if it has become a habit. It results in many social problems, such as child’s loss of confidence, lack of others’ respect to him, and his lack of respect to the desired values ​​of the society, such as honesty and trust. Consequently, he will be led to a deviation when he becomes old; especially if the child’s socially unaccepted behavior has not been directed. The research, thus, aims to examine the causes of lying in the most important stage of children’s life; that is, between (4-6) years. Such an aim helps to know about the individual reasons of lying among males and females from teachers’ perspectives. To meet the objective of the study, a number of (128) children

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Publication Date
Wed May 01 2019
Journal Name
Ieee International Electric Machines & Drives Conference (iemdc)
An Investigation of Short Translator Linear Machines for Use in a Free Piston Engine
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Publication Date
Tue Apr 28 2020
Journal Name
Journal Of Law And Humanities Sciences
Fair compensation for expropriation for the public benefit (A comparative study)
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The right to property is one of the most fundamental rights enjoyed by individuals, and most national constitutions and laws, as well as international conventions, have to be respected and protected only in accordance with the economic and social development of the country (the so-called public benefit) and in return for just compensation. What is fair compensation?

Publication Date
Tue Jan 01 2019
Journal Name
Technologies And Materials For Renewable Energy, Environment And Sustainability: Tmrees19gr
Characteristics measurement of Baghdad University radio telescope for hydrogen emission line
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The aim of this paper is to measure the characteristics properties of 3 m radio telescope that installed inside Baghdad University campus. The measurements of this study cover some of the fundamental parameters at 1.42 GHz. These parameters concentrated principally on, the system noise temperature, signal to noise ratio and sensitivity, half power beam width, aperture efficiency, and effective area. These parameters are estimated via different radio sources observation like Cas-A, full moon, sky background, and solar drift scan observations. From the results of these observations, these parameters are found to be approximately 64 K, 1.2, 0.9 Jansky, 3.7°, 0.54, and 3.8 m2 respectively. The parameters values have vital affect to quantitativ

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Publication Date
Thu Aug 01 2013
Journal Name
The Iraqi Journal Of Agricultural Sciences
VIBRATION MEASUREMENT AND PERFORMANCE EFFICIENCY OF GRASS MOWER
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The experiment was conducted in field of the University of Baghdad, Jadryia region, Baghdad to measure vibration and performance efficiency of grass mower (machine cutting grass). Vibration in three axes are longitudinal X , lateral Y and vertical Z in four places of mower machine during cutting grass and Practical Productivity, Efficiency and Fuel Consumption measured in this experiment . Factorial design (3 x 2) used, mower speeds included 1.9 3.6 and 6.4 km/hr and engine load included idling and full load according to randomized complete design were used in this experiment. Least Significant Design (LSD) 0.05 was used to compare the mean of treatment. Result were showed that the mower speed 6.4 km/hr recorded high productivity (0.6557 ha

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