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Dynamic Stability Analysis and Critical Speed of Rotor supported by a Worn Fluid film Journal Bearings
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In this paper, the effect of wear in the fluid film journal bearings on the dynamic stability of rotor bearing system has been studied depending on the development of new analytical equations for motion, instability threshold speed and steady state harmonic response for rotor with offset disc supported by worn journal bearings. Finite element method had been used for modeling the rotor bearing system. The analytical model is verified by comparing its results with that obtained numerically for a rotor supported on the short bearings. The analytical and numerical results showed good agreement with about 8.5% percentage error in the value of critical speed and about 3.5% percentage error in the value of harmonic response. The results obtained show that the wear in journal bearing decrease the instability threshold speed by 2.5% for wear depth 0.02 mm and 12.5% for wear depth 0.04 mm as well as decrease critical speed by 4.2% and steady state harmonic response amplitude by 4.3% for wear depth 0.02 mm and decrease the critical speed by 7.1% and steady state harmonic response amplitude by 13.9% for wear depth 0.04 mm.

 

 

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Publication Date
Sun Mar 01 2015
Journal Name
Baghdad Science Journal
Performance evolution of a hybrid thermal solar air conditioning system and compare it with a traditional system according to Iraq weather
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In a hybrid cooling solar thermal systems , a solar collector is used to convert solar energy into heat energy in order to super heat the refrigerant leaving the compressor, and this process helps in the transformation of refrigerant state from gaseous state to the liquid state in upper two-thirds of the condenser instead of the lower two-thirds such as in the traditional air-conditioning systems and this will reduce the energy needed to run the process of cooling .In this research two systems with a capacity of 2 tons each were used, a hybrid air-conditioning system with an evacuated tubes solar collector and a traditional air-conditioning system . The refrigerant of each type was R22.The comparison was in the amou

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Publication Date
Sat Jun 01 2013
Journal Name
Journal Of The College Of Languages (jcl)
The Intellectual as an Alien: A Study of Henry James's The Beast in the Jungle and James Joyce's "A Painful Case"
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This research paper studies the alienation of the intellectuals in the modern novel through the study of two alienated characters, John Marcher in Henry James's The Beast in the Jungle, and Mr. Duffy in James's Joyce's "A Painful Case." As a result of the complexity of life in the industrial societies, the individuals, especially the intellectual ones, feel themselves unable to integrate into social life; they fear society and feel that it endangers their individuality and independence. Thus, these characters live on the fringe of the societ

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Publication Date
Tue Dec 15 2020
Journal Name
Al-academy
Characteristics of Environment in Contemporary Iraqi and Iranian Pottery A Comparative Study (Saad Shakir- Muhammad Mahdi) A Model: قحطان عدنان محمود
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The Iraqi and Iranian pottery has a significant role in the contemporary world pottery space, despite the fact that influences created those formulation, thus the researcher supposes that there is a relation between the potter and his environment within Iraq's environment and Iran's environment, which are similar at times and different at other times. The researcher, hence, found himself in front of a number of questions:
1- How much was the Iraqi potter inspired by the environment compared to the Iranian potter?
2- Has the Iraqi and Iranian pottery been really inspired by the environment items or there were modified metaphors?
The current research aims at (identifying the influential environmental characteristics in the Iraq

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Publication Date
Tue Jan 13 2026
Journal Name
Cost Effectiveness And Resource Allocation
Quantifying the direct costs of diabetic retinopathy in a mixed healthcare system: a hospital-based study from governmental and patient perspectives
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Publication Date
Fri Feb 19 2021
Journal Name
Annals Of Telecommunications
Challenges and limits of fractal and slot antennas for WLAN, LTE, ISM, and 5G communication: a review paper
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Abstract Portable communication devices such as WLAN, WiMAX, LTE, ISM, and 5G utilize one or more of the triple bands at (2.32.7 GHz,3.4–3.6GHz,and5–6GHz)andsufferfromtheeffectofmultipathproblemsbecausetheyareusedinurbanregions.To date, no one has performed a review of the antennas used for these types of wireless communications. This study reviewed two types of microstrip antennas (slot and fractal) that have been reported by researchers (as a single element) using a survey that included the evaluation of several important specifications of the antennas in previous research, such as operating bandwidth, gain, efficiency, axial ratio bandwidth (ARBW), and size. The weaknesses in the design of all antennas were carefully identified to de

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Publication Date
Wed Dec 28 2022
Journal Name
Periodicals Of Engineering And Natural Sciences
Histological and immunohistochemical study of thyroid gland in Caucasian squirrel (Sciurus anamalus) (Gmelin, 1778) by using marker (Anti-Thyroglobulin, Code IR5090)
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The current study is designed to investigate the histological and immunohistochemical characteristics of the thyroid gland in adult male Sciurus anamalus. This study found that the thyroid gland of the Caucasian squirrel is located in the neck area, below the larynx, on both sides of the trachea. It has two lobes (right and left) with cylindrical shape. The histological studies revealed that the thyroid gland is surrounded by a capsule which consists of connective tissue and forming of two layers which are outer layer and inner layer, and a layer of adipose tissue appears overlapping the outer layer. The inner tissue of the gland consists of follicles with different shapes and sizes, and is lined with simple cuboidal epithelial tissue (foll

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Publication Date
Fri Aug 12 2022
Journal Name
Journal Of Research In Medical And Dental Science
Effects of Ozonated Water on Micro Leakage between Enamel and Fissure Sealants Prepared by Different Etching Technique (An in vitro Study)
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Effects of Ozonated Water on Micro Leakage between Enamel and Fissure Sealants Prepared by Different Etching Technique (An in vitro Study), Baraa M Jabar*, Muna S Khalaf

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Publication Date
Mon Nov 08 2021
Journal Name
Physica Scripta
Adsorption of the eosin yellow dye by nickel oxide nanoparticles catalyzes via oxalate co-precipitation method: isotherm, kinetic and thermodynamic studies
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Publication Date
Fri Dec 30 2022
Journal Name
Iraqi Journal Of Science
Structural, Optical, and Morphological Study of the Zinc Oxide Nano-Thin Films with Different Thickness Prepared by Pulsed Laser Deposition Technique
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The goal of this investigation is to prepare zinc oxide (ZnO) nano-thin films by pulsed laser deposition (PLD) technique through Q-switching double frequency Nd:YAG laser (532 nm) wavelength, pulse frequency 6 Hz, and 300 mJ energy under vacuum conditions (10-3 torr) at room temperature. (ZnO) nano-thin films were deposited on glass substrates with different thickness of 300, 600 and 900 nm. ZnO films, were then annealed in air at a temperature of 500 °C for one hour. The results were compared with the researchers' previous theoretical study. The XRD analysis of ZnO nano-thin films indicated a hexagonal multi-crystalline wurtzite structure with preferential growth lines (100), (002), (101) for ZnO nano-thin films with different thi

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Publication Date
Sun Sep 02 2012
Journal Name
Baghdad Science Journal
Determination of optimal conditions for laccase production by Pleurotus ostreatus using sawdust as solid medium and its use in phenol degradation
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The ability of four local fungal isolates for extracellular laccase production has been tested with five grams 1:1(w/v) humidified sawdust as substrate in mineral salt medium. After 21 day of incubation at 25±1 ? C and using one mycelial plug (5mm), higher level of laccase activity (0.15U/ml) and specific activity (15U/mg) were observed by Pleurotus ostreatus in comparison with other fungal isolates. The results of optimum conditions for laccase production from selected isolate showed that, the maximum laccase activity (0.55U/ml) and specific activity (55U/mg) were obtained at moisture ratio 1:3 (w/v), using 3 mycelial plugs (5 mm), after 15 days incubation period at 25±1 ? C. The results of phenol degradation by crud laccase revealed th

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