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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
Sat Jan 13 2024
Journal Name
Journal Of Advanced Research In Fluid Mechanics And Thermal Sciences
Influence of Surrounding Air Temperature and Humidity upon the Performance of a Gas Turbine Power Plant
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Nowadays, energy demand continuously rises while energy stocks are dwindling. Using current resources more effectively is crucial for the world. A wide method to effectively utilize energy is to generate electricity using thermal gas turbines (GT). One of the most important problems that gas turbines suffer from is high ambient air temperature especially in summer. The current paper details the effects of ambient conditions on the performance of a gas turbine through energy audits taking into account the influence of ambient conditions on the specific heat capacity ( , isentropic exponent ( ) as well as the gas constant of air . A computer program was developed to examine the operation of a power plant at various ambient temperature

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Publication Date
Sun Jan 30 2022
Journal Name
Heat Transfer
Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air
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Heat pipes and two‐phase thermosyphon systems are passive heat transfer systems that employ a two‐phase cycle of a working fluid within a completely sealed system. Consequently, heat exchangers based on heat pipes have low thermal resistance and high effective thermal conductivity, which can reach up to the order of (105 W/(m K)). In energy recovery systems where the two streams should be unmixed, such as airconditioning systems of biological laboratories and operating rooms in hospitals, heat pipe heat exchangers (HPHEs) are recommended. In this study, an experimental and theoretical study was carried out on the thermal performance of an air‐to‐air HPHE filled with two refrigerants as working fluids, R22 and R407c. The heat pipe he

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Publication Date
Mon Jan 08 2018
Journal Name
Journal Of Pharmaceutical Sciences And Research
Pryparation, characterization and biological activity of new derivatives of 2-biphenyl-3-aminomethylimidazo(1,2-a)pyrimidine
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Publication Date
Fri Mar 15 2019
Journal Name
Al-khwarizmi Engineering Journal
Experimental and Theoretical Study of the Energy Flow of a Two Stages Four Generators Adsorption Chiller
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This work is concerned with a two stages four beds adsorption chiller utilizing activated carbon-methanol adsorption pair that operates on six separated processes. The four beds that act as thermal compressors are powered by a low grade thermal energy in the form of hot water at a temperature range of 65 to 83 °C.  As well as, the water pumps and control cycle consume insignificant electrical power. This adsorption chiller consists of three water cycles. The first water cycle is the driven hot water cycle. The second cycle is the cold water cycle to cool the carbon, which adsorbs the methanol. Finally, the chilled water cycle that is used to overcome the building load. The theoretical results showed that average cycle cooling power

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Publication Date
Fri Jul 18 2025
Journal Name
Applied Water Science
Pathway of total petroleum hydrocarbon in a lotic ecosystem: water and sediment of Tigris River, Iraq
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Abstract<p>The monitoring of lotic ecosystems is an important issue. This study investigated the total petroleum hydrocarbons (THP) in the Tigris River within Baghdad City, Iraq, which is considered the ultimate water supply source of the city. The study included measurement of THP concentrations, distribution, and origins of total petroleum hydrocarbons (TPHs) in various matrices (water, sediment, and macrophyte) in Tigris River within Baghdad City, in addition to some environmental factors during two seasons (dry and wet) for October 2020 to April 2021. The sampling was collected from three sites along the river. Thirteen compounds were identified in the current investigation from total petroleum h</p> ... Show More
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Publication Date
Mon Jun 05 2023
Journal Name
Al-khwarizmi Engineering Journal
A Review of the Stereo lithography 3D Printing Process and the Effect of Parameters on Quality
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Stereo lithography (SLA) three-dimensional (3D) printing process is a type of additive manufacturing techniques that uses digital models from computer-aided design to automatically produce customized 3D objects. Around 30 years, it has been widely utilized in the manufacturing, design, engineering, industrial sectors and its applications in dentistry for manufacturing prosthodontics are very important. The stereo lithography technology is highly regarded because it can produce items with excellent precision especially when selecting the best process parameters. This review article offers a useful and scientific summary of SLA three-dimensional printing technology and its brief history. The specific type of 3D printers which is SLA t

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Scopus (28)
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Publication Date
Mon Jun 05 2023
Journal Name
Al-khwarizmi Engineering Journal
A Review of the Stereo lithography 3D Printing Process and the Effect of Parameters on Quality
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Stereo lithography (SLA) three-dimensional (3D) printing process is a type of additive manufacturing techniques that uses digital models from computer-aided design to automatically produce customized 3D objects. Around 30 years, it has been widely utilized in the manufacturing, design, engineering, industrial sectors and its applications in dentistry for manufacturing prosthodontics are very important. The stereo lithography technology is highly regarded because it can produce items with excellent precision especially when selecting the best process parameters. This review article offers a useful and scientific summary of SLA three-dimensional printing technology and its brief history. The specific type of 3D printers which is SLA type b

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Publication Date
Wed Jan 01 2025
Journal Name
Science Progress
Impact of COVID-19 on the prevalence of oral and maxillofacial disorders: A retrospective cohort study
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Publication Date
Sun Jun 02 2019
Journal Name
Journal Of The College Of Languages (jcl)
Analysis of Verbs Forms in Sa’eed Faeeq’s Short Story: Cloud in the Sky: Sait Faik'in "Havada Bulut" Adlı Hikayesinde Fiil Kiplerinin İncelenmesi.
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This research paper which is entitled “Analysis of Verbs Forms in Sa’eed Faeeq’s Short Story: Cloud in the Sky” deals with the forms of verbs (i.e., kinds of tenses and suffix analysis). It is one of the applied studies. Verbs are basic elements in Turkish sentences. Their function is to state the predicate which is a sentential essential part. Verbs denote sentence construction, action and formal aspects. Forms are added to the base of verbs in the Turkish language giving the verbs their final structures. Such structures are set in a distinct planned way. The verbs used in the Turkish language which are distinguished by one of these forms are known as simple tense verbs.

Sait Faik'in ( "Havada Bulut" adlı Hikayesinde Fi

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Publication Date
Tue Jan 01 2019
Journal Name
International Journal Of Pharmaceutical Research
New method for the evaluation of propranolol with phosphotungstic acidvialong distance chasing photometer (NAG-ADF-300-2) using continuous flow injection analysis
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A new, simple and sensitive method was used forevaluation of propranolol withphosphotungstic acidto prove the efficiency, reliability and repeatability of the long distance chasing photometer (NAG-ADF-300-2) using continuous flow injection analysis. The method is based on reaction between propranolol and phosphotungstic acid in an aqueous medium to obtain a yellow precipitate. Optimum parameters was studied to increase the sensitivity for developed method. A linear range for calibration graph was 0.007-13 mmol/L for cell A and 5-15 mmol/L for cell B, and LOD 207.4792 ng/160 µL and 1.2449 µg/160 µL respectively to cell A and cell B with correlation coefficient (r) 0.9988 for cell A, 0.9996 for cell B, RSD% was lower than 1%, (n=8) for the

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