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alkej-778
Comparative study of vibration analysis in rotary shafts between Rayleigh's and Dunkerley's methods
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The importance of vibrations in rotating rotors in engineering applications has been examined, as has the best approach to interpreting vibration data. The most extensively used analytical approaches for rotating shaft vibration analysis have been investigated. In this research, a detailed study was made of the Rayleigh and Dunkerley methods due to their importance in the special calculations to find the amplitude of vibrations in the rotation system. The multi-node method was used to calculate both Dunkerley's and Rayleigh's methods. An experimental platform was built to study the vibrations that occur in the rotating shafts, and the results were compared with theoretical calculations and with different distances of the bearings. It proved that there is very little error between the experimental and theoretical results. The vibration signal from the sensors was analyzed using the LABVIEW program. Rayleigh's method was compared to the exact method, and it was considered the most accurate method. It was found that it made very little difference, up to about 0.06%. As for the Dunkerley method, the difference between it and the proper method is about 4%, which is acceptable. Then a comparison was made between Rayleigh's and Dunkerley's methods, and it was found that Dunkerley's method is the most appropriate in the calculations.

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Publication Date
Sat Jan 31 2026
Journal Name
Journal Of Baghdad College Of Dentistry
A Comparative Study of Clinicopathological and Immunohistochemical Expression of CD1a, RANK and RANKL in Langerhans Cell Histiocytosis of Jaw and Skull Lesions
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Background: Langerhans' cell histiocytosis (LCH) is a group of conditions affecting the reticuloendothelial system. It includes Letterer-Siwe disease, Hand-Schuller-Christian disease and eosinophilic granuloma and most often presents in childhood. Materials and methods: Twenty-five cases of LCH were diagnosed histologically and confirmed by CD1a antibody and assessed immunohistochemically using anti-RANKL and anti-RANK antibodies to evaluate osteoclastogenic mechanism. Results: Regarding jaw cases, there was a significant correlation between CD1a and RANK (P=0.016). While in the skull, highly significant correlation existed between RANK and RANKL (p=0.001). Among the sites, there was no statistically significant difference found for each

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Publication Date
Thu Dec 15 2022
Journal Name
Arab World English Journal
Genre-Based Analysis of Selected Political Debates: A Discourse Analysis Study
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The researchers of the present study have conducted a genre analysis of two political debates between American presidential nominees in the 2016 and 2020 elections. The current study seeks to analyze the cognitive construction of political debates to evaluate the typical moves and strategies politicians use to express their communicative intentions and to reveal the language manifestations of those moves and strategies. To achieve the study’s aims, the researchers adopt Bhatia’s (1993) framework of cognitive construction supported by van Emeren’s (2010) pragma-dialectic framework. The study demonstrates that both presidents adhere to this genre structuring to further their political agendas. For a positive and promising image

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
Effect Of Using Quantitative Methods Of Demand Forecasting In Improving Of Supply Chain Performance:" Case Study In One Of An Industerial Organization"
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Objecte The study aims to test the effect of using the appropriate quantitative method of demand forecasting in improving the performance of supply chain of the aviation fuel product ( The study sample), One of the products of the Doura refinery (The study site), By testing a set of quantitative methods of demand forecasting using forecasting error measurements, and choosing the least faulty, most accurate and reliable method and adept it in the building  chain.

Is the study of problem through a starting with the fol

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Publication Date
Fri Nov 28 2025
Journal Name
Al-rafidain Journal Of Medical Sciences ( Issn 2789-3219 )
Comparative Efficacy of Biologics vs. Conventional Therapies in Psoriasis: A Meta-Analysis of a Decade of Progress From 2015 to 2025
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Background: The treatment of moderate-to-severe psoriasis has advanced significantly with the use of biologic treatments. Objective: To compare the effectiveness, safety, and impact on quality of life of biologic therapies versus conventional systemic therapies for moderate-to-severe psoriasis, using evidence from 2015 to 2025, focusing on the implications for understudied regions such as Iraq and the Middle East. Methods: Data was collected using "Embase," "MEDLINE," "PubMed," and "Cochrane Central Register." The study includes 45 randomized controlled trials. Additionally, 25 key real-world evidence studies were included for qualitative synthesis to provide context on long-term drug survival, quality of life, and regional applicab

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Publication Date
Wed Aug 30 2023
Journal Name
Baghdad Science Journal
Post COVID-19 Effect on Medical Staff and Doctors' Productivity Analysed by Machine Learning
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The COVID-19 pandemic has profoundly affected the healthcare sector and the productivity of medical staff and doctors. This study employs machine learning to analyze the post-COVID-19 impact on the productivity of medical staff and doctors across various specialties. A cross-sectional study was conducted on 960 participants from different specialties between June 1, 2022, and April 5, 2023. The study collected demographic data, including age, gender, and socioeconomic status, as well as information on participants' sleeping habits and any COVID-19 complications they experienced. The findings indicate a significant decline in the productivity of medical staff and doctors, with an average reduction of 23% during the post-COVID-19 period. T

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Publication Date
Wed Feb 05 2020
Journal Name
Political Sciences Journal
Populism in the Middle East: Discourse and Comparative Characteristics
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Abstract: The premise of the study is that populism is a process of building political views and critical intellectual orientations among the general public. It is transformed into mass beliefs by mobilizing the society ideologically and continuously in order to reach or control the circle of authority. We distributed the study topics to four sections: In the second, we will discuss the contents of contemporary populism and how other forms of populism evolved historically. The third is to discuss the political discourse of populism among the military regimes and the comparative Islamic parties in the Middle East, especially in terms of the essence and the intellectual foundations. The fourth section seeks to examine the characteristics o

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Publication Date
Fri Mar 01 2019
Journal Name
Al-khwarizmi Engineering Journal
A Finite Element Analysis for the Damaged Rotating Composite Blade
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In this paper, the finite element method is used to study the dynamic behavior of the damaged rotating composite blade. Three dimensional, finite element programs were developed using a nine node laminated shell as a discretization element for the blade structure (the same element type is used for damaged and non-damaged structure). In this analysis the initial stress effect (geometric stiffness) and other rotational effects except the carioles acceleration effect are included.  The investigation covers the effect speed of rotation, aspect ratio, skew angle, pre-twist angle, radius to length, layer lamination and fiber orientation of composite blade. After modeling a non-damaged rotating composite blade, the work procedure was to ap

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Publication Date
Fri Sep 16 2016
Journal Name
Journal Of Earthquake Engineering
Dynamic Response of Saturated Soil - Foundation System Acted upon by Vibration
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In this study, the response and behavior of machine foundations resting on dry and saturated sand was investigated experimentally. In order to investigate the response of soil and footing to steady state dynamic loading, a physical model was manufactured to simulate steady state harmonic load at different operating frequencies. Total of 84 physical models were performed. The footing parameters are related to the size of the rectangular footing and depth of embedment. Two sizes of rectangular steel model footing were tested at the surface and at 50 mm depth below model surface. Meanwhile the investigated parameters of the soil condition include dry and saturated sand for two relative densities 30% and 80%. The response of the footing was ela

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Publication Date
Tue Oct 30 2018
Journal Name
Journal Of Engineering
Active Vibration Control of Cantilever Beam by Using Optimal LQR Controller
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Many of mechanical systems are exposed to undesired vibrations, so designing an active vibration control (AVC) system is important in engineering decisions to reduce this vibration. Smart structure technology is used for vibration reduction. Therefore, the cantilever beam is embedded by a piezoelectric (PZT) as an actuator. The optimal LQR controller is designed that reduce the vibration of the smart beam by using a PZT element.  

In this study the main part is to change the length of the aluminum cantilever beam, so keep the control gains, the excitation, the actuation voltage, and mechanical properties of the aluminum beam for each length of the smart cantilever beam and observe the behavior and effec

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Publication Date
Thu Jan 01 2015
Journal Name
Conference Proceedings Of The Society For Experimental Mechanics Series
A comparative study of mode decomposition to relate next-ERA, PCA, and ICA modes
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This paper discusses a comparative study to relate parametric and non-parametric mode decomposition algorithms for response-only data. Three popular mode decomposition algorithms are included in this study: the Eigensystem Realization Algorithm with the Natural Excitation Technique (NExT-ERA) for the parametric algorithm, as well as the Principal Component Analysis (PCA) and the Independent Component Analysis (ICA) for the non-parametric algorithms. A comprehensive parametric study is provided for (i) different response types, (ii) excitation types, (iii) system damping, and (iv) sensor spatial resolution to compare the mode shapes and modal coordinates of using a 10-DOF building model. The mode decomposition results are also compared using

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