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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
Thu Aug 31 2017
Journal Name
Journal Of Engineering
Study and Analysis of Concentric Shell and Double Tube Heat Exchanger Using - Al 2 O 3 Nanofluid
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    Heat exchanger is an important device in the industry for cooling or heating process. To increase the efficiency of heat exchanger, nanofluids are used to enhance the convective heat . transfer relative to the base fluid. - Al2O3/water nanofluid is used as cold stream in the shell and double concentric tube heat exchanger counter current to the hot stream basis oil. These nanoparticles were of particle size of 40 nm and it was mixed with a base fluid (water) at volume
concentrations of 0.002% and 0.004%. The results showed that each of Nusselt number and overall heat transfer coefficient increased as nanofluid concentrations increased. The pressure drop of nanofluid increased slightly than the base fluid because

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Publication Date
Wed Dec 23 2020
Journal Name
2020 International Conference On Advanced Science And Engineering (icoase)
A Comparative Study Using LZW with Wavelet or DCT for Compressing Color Images
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As a result of the significance of image compression in reducing the volume of data, the requirement for this compression permanently necessary; therefore, will be transferred more quickly using the communication channels and kept in less space in memory. In this study, an efficient compression system is suggested; it depends on using transform coding (Discrete Cosine Transform or bi-orthogonal (tap-9/7) wavelet transform) and LZW compression technique. The suggested scheme was applied to color and gray models then the transform coding is applied to decompose each color and gray sub-band individually. The quantization process is performed followed by LZW coding to compress the images. The suggested system was applied on a set of seven stand

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Publication Date
Thu Apr 03 2025
Journal Name
Isa Transactions
Optimal hybrid type-3 fuzzy controller for horizontal axis wind turbines: Comparative study
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The blade pitch angle (BPA) controller is key factor to improve the power generation of wind turbine (WT). Due to the aerodynamic structural behavior of the rotor blades, wind turbine system performance is influenced by pitch angle and environmental conditions such as wind speed, which fluctuate throughout the day. Therefore, to overcome the pitch angle control (PAC) problem, high wind speed conditions, and due to type-1 and type-2 fuzzy logic limitations for handling high levels of uncertainty, the newly proposed optimal hybrid type-3 fuzzy logic controller has been applied and compared since type-3 fuzzy controllers utilize three-dimensional membership functions, unlike type-2 and type-1 fuzzy logic controllers. In this paper six differen

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Publication Date
Fri Apr 01 2022
Journal Name
Journal Of Engineering
Numerical study of natural convection in an annulus between two concentric cylinders provided with metal foam fins
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Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh numb

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Publication Date
Mon Sep 30 2019
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
A Comparative Study of the Influence of Different Types of Polymers on Viscosity Index and Pour Point of Iraqi Base Oils
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In this study, the effects of blending the un-branched acrylate polymer known as Poly (n-decyl acrylate), and the branched acrylate polymer known as Poly (iso-octyl acrylate), on the viscosity index (VI), and the pour point of the Iraqi base stocks 40, and 60 respectively, were investigated. Toluene was used as a carrier solvent for both polymer types. The improvement level of oils (VI, & pour point) gained by blending the oil with the acrylate derived polymers was compared with the values of (VI, and pour point) gained by blending the oil with a commercial viscosity index, and pour point improver. The commercial lubricant additive was purchased and used by Al-Daura Refineries. It consisted of an un-known olefin copolymer dissolved i

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Publication Date
Tue Dec 15 2020
Journal Name
Al-academy
Methods of Acting Performance and Watching Industry in Street Theatre- Play (Sold) - A Model: بهاء زهير كاظم
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  The audience is one of the important practical elements in the theatrical show and its importance is not confined to its static activity as a receiver element only, rather it went beyond that issue as an effective and influential element in the proceedings of the show and the process of meaning construction, that it gains an active role in the construction and production of the connotation that influences and is influenced by the actor, where the communication channels are open between the two sides, consequently a kind of watching and joint interaction happens between them. Thus, it has become necessary for the actor to create a suitable environment for the onlookers in order for it to be an essential part of the show system. The

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Publication Date
Thu Aug 04 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Mutual Impact between Current Account status and selected Total Variables Iraq : study status 2004-2019
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The flexibility of interaction between the movement of macroeconomic variables that affect and are affected by the balance of payments, especially the movement of the current account, implies a perception of the maturity of economic development and what the theory assumes from the launch of a wide range of economic movement that varies in the degree of its influence according to the level of economic development and the vitality of the internal/external overlap relations through the assumed response to the movement of the macroeconomic variables. On this basis, it is possible to estimate the soundness and rationality of the economic decision taken that takes into account the required reciprocal repercussions between the current a

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Publication Date
Thu Mar 19 2015
Journal Name
Al-academy
Theatrical Visual System between the Cultural Identity and Globalization Culture Iraqi Theatre as Case Study
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Publication Date
Wed Jun 01 2011
Journal Name
Journal Of The College Of Languages (jcl)
Areas in phonetics and phonology Differences Between Speech and Writing
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In any language there is some amount of difference between written language (planned) and spoken language (spontaneous). Since planned speech could be considered a form of written language, it could be inferred that there are also differences between planned speech and spontaneous speech. Some of these differences are very clear in terms of syntax, lexis, phonology and discourse.  These differences are highlighted in order to make a clear distinction between spontaneous and planned speech.

             This paper is an attempt to show the differences between the two forms of a language (written & spoken English) as far as number of linguistic features are tackle

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Publication Date
Mon Jan 28 2019
Journal Name
Journal Of The College Of Education For Women
The RoleThe Role of the Arbitration Treaty and Decisiveness in the Consolidation of Relations Between Britain and France (1903-1904) of the Arbitration Treaty and Decisiveness in the Consolidation of Relations Between Britain and France (1903-1904)
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The Risks Faced by Britain in their Areas of Influence at the Beginning of the Twentieth Century Drove her to the Alliance with the State of European such as France, and Contributed to the Tireless and made by the British and French Politicians in the Consolidation of Friendly Relations between the two Countries Efforts and Strengthened Cooperation in a Positive Way to Visit the king of Britain's Edward VII to France, Offset by Visit French President Loubet to Britain in the Same Year, those Negotiations Bore Fruit between the two Countries for Reaching a Contract Arbitration and Decisiveness between Britain and France Treaty on the Fourteenth of November 1903, Promised that Treaty First Step that Paved the Way for a General Agreement be

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