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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
Wed Jun 01 2011
Journal Name
Journal Of Engineering
ESTIMATION OF RELATIONSHIP BETWEEN COEFFICIENT OF CONSOLIDATION AND LIQUID LIMIT OF MIDDLE AND SOUTH IRAQI SOILS
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In this paper, a relationship between the liquid limit and the coefficient of consolidation of Iraqi soils are studied. The samples of soil used in study are undisturbed silty clay. These samples are taken from different locations and depths of Middle and South of Iraq by cooperation with Consulting Engineering Bureau- University of Baghdad- College of Engineering. The depth reached about 20 meters. The experimental work is made to calculate the liquid limit and the coefficient of consolidation. From these sites, 280 points are obtained. The relationship between the liquid limit and the coefficient of consolidation is drawn as a curve. This curve is studied and compared with the curve that obtained from other studies. From these curves, it

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Publication Date
Mon Dec 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
Knowledge of marketing and its impact on the performance of the company for the distribution of oil products –an exploratory study of the views of asample in the general company for oil products distribution/ Distribution Authority, Baghdad
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This study seeks to address the impact of marketing knowledge dimensions (product, price, promotion, distribution) on the organizational performance in relation to a number of variables which are (efficiency, effectiveness, market share, customer satisfaction), and seeks to reveal the role of marketing knowledge in organizational performance.

In order to achieve the objective of the study the researcher has adopted a hypothetical model that reflects the logical relationships between the variables of the study. In order to reveal the nature of these relationships, several hypotheses have been presented as tentative solutions and this study seeks to verify the validity of these hypotheses.

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Publication Date
Thu Apr 18 2019
Journal Name
Al-kindy College Medical Journal
Evaluation of Risk Management among Managers of the Primary Health Care Centers in Baghdad City: Comparative Study
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Background: Several risk managem-ent standards had been developed including the Project Management Institute, the National Institute of Standards and Technology, actuarial societies, and ISO standards.

Objective: The study aimed at evaluating risk management among managers of model and ordinary primary health care centers in Baghdad City and comparing the risk management among these centers.

Methods: A descriptive comparative des

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Publication Date
Fri Mar 15 2024
Journal Name
Journal Of Baghdad College Of Dentistry
Efficiency of osseodensification versus screw expansion technique for augmentation of narrow alveolar ridges: A comparative clinical study
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Background: Alveolar ridge expansion is proposed when the alveolar crest thickness is ≤5 mm. The screw expansion technique has been utilized for many years to expand narrow alveolar ridges. Recently, the osseodensification technique has been suggested as a reliable technique to expand narrow alveolar ridges with effective width gain and as little surgical operating time as possible. The current study aimed to compare osseodensification and screw expansion in terms of clinical width gain and operating time. Materials and methods: Forty implant osteotomies were performed in deficient horizontal alveolar ridges (3–5 mm). A total of 19 patients aged 21–59 years were randomized into two groups: the screw expansion group, which invo

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Publication Date
Tue Feb 21 2017
Journal Name
Journal Of Entomology And Zoology Studies
Comparison study between a crude bacterial suspension and purified pseudomonal alkaline protease enzyme effect on the rabbit interleukin-2 bacterial keratitis
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Publication Date
Thu Mar 01 2018
Journal Name
Journal Of Engineering
Tribological Characteristics Evaluation of Mustard Oil Blends
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A progressive increase in the desire for environmentally friendly lubricants by users and strict government regulations for the use of these lubricants has provided an opportunity to use plant oils as biodegradable lubricants, therefore vegetable oils have been investigated to replace oil lubricants because of their maintaining the conditions of nature (environment) properties. In this paper, the influences of the blending ratio of mustard seeds oil with commercial mineral oil (SAE40) on the tribological characteristics were investigated and compared with mineral oil using the four-ball tribotester. Mustard seeds oil was blended with mineral oil at a volumetric ratio ranging from 22.5 to 90%. All experimental works were

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Publication Date
Thu Oct 01 2009
Journal Name
Renewable Energy
The characteristics of anisotype CdS/CdTe heterojunction
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Publication Date
Wed Sep 01 2021
Journal Name
Iraqi Journal Of Physics
Optical Characteristics of Vitamin D3 Soft Gel
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In this work, the linear properties of Vitamin D3-5000IU soft gel were investigated by measuring its absorption and fluorescence spectra. It was observed that there was a shift towards longer wavelength within limits (75 nm), with quantitative efficiency equal to (33.58%). The values of absorbance were used to calculate the extinction coefficient, optical refractive index, optical conductivity and optical dielectric constant values.

The non-linear properties of Vitamin D3-5000IU soft gel was also studied using the Z-Scan technique by using Neodymium-doped Yttrium Garnet (Nd: YAG) continuous laser (CW) emitting in       &n

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Publication Date
Fri Jul 21 2023
Journal Name
Journal Of Engineering
Corrosion-Resistance Characteristics of Concrete Containing Furfural
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Corrosion inhibiting admixtures are unique among other methods to protect reinforced concrete from corrosion damage. In this study, the effect of furfural on the fresh and hardened properties of concrete mixes of 35 and 45 MPa compressive strengths as well as the corrosion inhibition of furfural was evaluated. Furfural was added at different dosages (1, 2 and 3% by weight of cement) with and without superplasticizer (HRWR). Different electrochemical measurements were performed (Half-cell potential, Tafel plot and linear polarization resistance). Electrochemical measurements confirmed that furfural dramatically reduces the rate of corrosion; the inhibition efficiencies were 62.7 and 63.8 % due to 3% furfural addition to 35 and 45MPa-concr

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Publication Date
Thu Nov 02 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Electrical Characteristics of Planar Pbthalocyanine Thin Films
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The   electrical     properties   of   thin   film    interdigital    metal­

phthalocyanine - metal devices have been studied with regard to purity and electrode material . Devices utilising phthalocyanines ( H2 Pc ,

NiPc and CuPc) films with Au, Ag , Cu ' In and AI electrodes have been prepared with Pc layers fabricated  from  both as - supplied  Pc powder and entrainer - subeimed  material . The results indicate that

sublimed phthalocyanine with gold electrodes offers the best material

combination with regard to linearity , reversibility and reproducibility. Measurements  of  current &nbs

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