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Optimal insulation design of form-wound stator winding with stress grading system under fast rise-time excitation
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The effective insulation design of the stress grading (SG) system in form-wound stator coils is essential for preventing partial discharges and excessive heat generation under pulse-width modulation excitation. This paper proposes a method to find the optimal insulation design of the SG system aimed at reducing the dielectric and thermal stresses in the machine coil. The non-uniform transmission line model is used to predict the voltage propagation along the overhang, SG, and slot regions considering the variation in the physical properties of the insulation layers. The machine coil parameters for different insulation materials are calculated by using the finite element method. Two optimization algorithms, fmincon and particle swarm optimization (PSO), are applied and compared to find the optimal thickness and material properties of each insulation layer as well as the length and location of the SG system. The results under different rise-time excitation show that the optimized geometry by using PSO can produce a higher reduction in the dielectric and thermal stresses, as well as in the maximum overvoltage along the machine coil than the original geometry and the optimized geometry using fmincon. The machine coil model is validated by means of comparisons with experimental measurements.

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Publication Date
Fri Mar 01 2019
Journal Name
Al-khwarizmi Engineering Journal
A Digital-Based Optimal AVR Design of Synchronous Generator Exciter Using LQR Technique
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In this paper a new structure for the AVR of the power system exciter is proposed and designed using digital-based LQR. With two weighting matrices R and Q,  this method produces an optimal regulator that is used to generate the feedback control law. These matrices are called state and control weighting matrices and are used to balance between the relative importance of the input and the states in the cost function that is being optimized. A sample power system composed of single machine connected to an infinite- bus bar (SMIB) with both a conventional and a proposed Digital AVR (DAVR) is simulated. Evaluation results show that the DAVR damps well the oscillations of the terminal voltage and presents a faster respo

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Publication Date
Thu May 18 2023
Journal Name
Journal Of Engineering
Experimental Study for Materials Prosthetic above Knee Socket under Tensile or Fatigue Stress with Varying Temperatures Effect
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The residual limb within the prosthesis, is often subjected to tensile or fatigue stress with varying temperatures. The fatigue stress and temperatures difference which faced by amputee during his daily activities will produces an environmental media for growth of fungi and bacteria in addition to the damage that occurs in the prosthesis which minimizingthe life of the prosthetic limb and causing disconfirm feeling for the amputee.

In this paper, a mechanical and thermal properties of composite materials prosthetic socket made of different lamination for perlon/fiber glass/perlon, are calculated by using tesile test device under varying temperatures ( from 20oC to 60oC), also in this paper a device for measuring rotational bendin

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Publication Date
Sat Oct 16 2021
Journal Name
Energies
Performance Analysis of a Solar Cooling System with Equal and Unequal Adsorption/Desorption Operating Time
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In solar-thermal adsorption/desorption processes, it is not always possible to preserve equal operating times for the adsorption/desorption modes due to the fluctuating supply nature of the source which largely affects the system’s operating conditions. This paper seeks to examine the impact of adopting unequal adsorption/desorption times on the entire cooling performance of solar adsorption systems. A cooling system with silica gel–water as adsorbent-adsorbate pair has been built and tested under the climatic condition of Iraq. A mathematical model has been established to predict the system performance, and the results are successfully validated via the experimental findings. The results show that, the system can be operational

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Publication Date
Thu Nov 15 2018
Journal Name
Journal Of Mathematical Imaging And Vision
A New Hybrid form of Krawtchouk and Tchebichef Polynomials: Design and Application
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Publication Date
Wed Aug 11 2021
Journal Name
Neuroquantology
Correlation of Vitamin D Level with Electrophysiological Findings and Clinical Grading in Carpal Tunnel Syndrome
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Carpal tunnel syndrome is a neurological disease that presented with paresthesias, pain, and numbness in the hand's median nerve compression. Vitamin D was assumed to affect both electrophysiological &clinical gradings, the study aims to assess the correlation between the deficiency of vitamin D and both electrophysiological and clinical gradings. This study was conducted in Ghazi Alhariri Hospital during the period from the first of November/2020 to the twenty-eighth of February/2021, fifty five individuals were referred to as Carpal tunnel syndrome patients, and compared to (55) control individuals, blood samples were withdrawn from the patients (3ml), centrifuged and kept in the freezer (-20°C) until the time of analysis of

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Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
Design Sampling Plan when Life Time Follows Logistic Distribution
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Design sampling plan was and still one of most importance subjects because it give lowest cost  comparing with others, time live statistical distribution should be known to give best estimators for  parameters of sampling plan and get best sampling plan.

Research dell with design sampling plan when live time distribution follow Logistic distribution with () as location and shape parameters, using these information can help us getting (number of groups, sample size) associated with reject or accept the Lot

Experimental results for simulated data shows the least number of groups and sample size needs to reject or accept the Lot with certain probability of

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Publication Date
Tue Dec 01 2020
Journal Name
Propulsion And Power Research
Heat transfer enhancement from heat sources using optimal design of combined fins heat-sinks
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Publication Date
Tue Dec 20 2011
Journal Name
المؤتمر الدولي الثالث للاحصائيين العرب
Use a form ARX(p,q) to estimate time series for the Iraqi Economy
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Due to the lack of statistical researches in studying with existing (p) of Exogenous Input variables, and there contributed in time series phenomenon as a cause, yielding (q) of Output variables as a result in time series field, to form conceptual idea similar to the Classical Linear Regression that studies the relationship between dependent variable with explanatory variables. So highlight the importance of providing such research to a full analysis of this kind of phenomena important in consumer price inflation in Iraq. Were taken several variables influence and with a direct connection to the phenomenon and analyzed after treating the problem of outliers existence in the observations by (EM) approach, and expand the sample size (n=36) to

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Publication Date
Thu Feb 27 2020
Journal Name
Iraqi Journal Of Science
Gene Expression of pelA and pslA in Pseudomonas Aeruginosa under Gentamicin Stress
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     Pseudomonas aeruginosa produces an extracellular biofilm matrix that consists of nucleic acids, exopolysaccharides, lipid vesicles, and proteins. Alginate, Psl and Pel are three exopolysaccharides that constitute the main components in biofilm matrix, with many biological functions attributed to them, especially concerning the protection of the bacterial cell from antimicrobial agents and immune responses. A total of 25 gentamicin-resistant P. aeruginosa selected isolates were enrolled in this study. Biofilm development was observed in 96% of the isolates. In addition, the present results clarified the presence of pelA and pslA in all the studied isolates. The expression of these genes was very low. Even though all biof

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Publication Date
Sun Sep 01 2013
Journal Name
Baghdad Science Journal
Induction of antioxidant enzymes in wheat (Triticum spp.) grown under salt stress
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A pot culture experiment was conducted at the greenhouse of soil and water resources department in College of Agriculture, University of Baghdad in Abo-Ghraib at season 2009-2010 to investigate the effects of using foliar application of some macro and micronutrients in induce antioxidant enzymes in wheat grown under salt stress . Doar85 planted under three levels of salt stress, and three combinations of foliar application were used from nutrients (K+ Ca) at 3000 and 1500 mg.L-1 respectively, and (Fe + Zn + Mn) at 30, 20, and 10 mg.L-1 respectively , and ( K+ Ca) + (Fe+ Zn + Mn). The results showed that increasing levels of sodium chloride in the irrigation of water significantly increased at p<0.05 level SOD and POD activity

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