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Sliding Mode Vibration Suppression Control Design for a Smart Beam
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Active vibration control is the main problem in different structure. Smart material like piezoelectric make a structure smart, adaptive and self-controlling so, they are effective in active vibration control. In this paper piezoelectric elements are used as sensors and actuators in flexible structures for sensing and actuating purposes, and to control the vibration of a cantilever beam by using sliding mode control. The sliding mode controller (SMC) is designed to attenuate the vibration induced by initial tip displacement which is equal to 15 mm.  It is designed based on the balance realization reduction method where three states are selected for the reduced model from the 24th states that describe the cantilever beam according to the FEM. These states are most controllable and observable. The stability and control performance for the proposed SMC are proved using candidate Lyapunov function and the equivalent control concept. The control spillover, which is the sources of instability, is completely avoided as ensured within the control performance proof.

            Numerical simulations are preformed to test the vibration attenuation ability of the proposed SMC. For 15 mm initial tip displacement, the piezoelectric actuator was found able to reduce the tip displacement to about (0.2) mm within (2.5 s), while it is equal to (3.5) mm with the open loop case. Moreover, the induced chattering in system response, due to the discontinuous control action, is removed by approximating the signum function by a continuous arctan function. As a result  a smoother response are obtained with the same control performance as can be shown in the sliding variable, the control input voltage and the tip displacement plots.

 

 

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Publication Date
Tue Jun 20 2023
Journal Name
Baghdad Science Journal
Improving propagation of Echinacea purpurea and its content of some active compounds by using Tyrosine and Salicylic acid in vitro
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The seed propagation is the predominant method of Echinacea propagation, which has been criticized for its time-consuming control over the separation factor and the uncertainty of pathogen-free plants produced by this method. The technology of tissue culture has provided multiple opportunities for the production of secondary metabolites continuously without being restricted to a specific season, due to the possibility of controlling the environmental conditions and the components of the nutrient medium needed by the plant. This study was conducted to investigate the effects of salicylic acid as elicitor and tyrosine as precursor on propagation and some secondary compounds production in coneflower in vitro. The result showed the superiori

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Publication Date
Sun Apr 03 2005
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Serum Trace Elements ( Se+2, Cu+2, Zn+2) in Patients with Behcet's Disease
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Background: Extensive reports denote the biological role of trace elements (Cu Zn ", Se ') in many various physiological and pathological conditions, one of the list is shown to be Behcet's disease (BD).The aim of this study was directed towards the distribution of trace elements (Cu 2,Zn, 2,Se 2) in sera of BD patients, and control groups.
Methods: Fifty Arab Iraqi patients who fulfdled the ISO criteria for diagnosis BD.compared with 21 patients control with recurrent oral ulcer (ROU), healthy control groups (2Ihealthy relative and 21healthy volunteer). Typing HLA Class I was carried out at Alkarama hospital, by using microlympho-cytotoxicity test. The concentrations of serum Cu ', Zn ", and Se" were determined by atomic absorption s

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Publication Date
Wed Nov 30 2022
Journal Name
Iraqi Journal Of Science
Determination of Critical Stresses in Frozen Soils Under Wave Acoustic Loading
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    The issues related to the development of permafrost and seasonally frozen soils without their preliminary loosening by various earthmoving machines with active working bodies, magnetostrictive vibrators, that soften dense and frozen soils using acoustic elastic waves, are considered. The analytical studies allowed us to establish the regularities of the process of destruction of frozen soil by active teeth of bucket working bodies, according to which, the formulas for calculating the critical tensile stress and shear resistance were obtained. The research results allow us to determine the main parameters of wave loading for both a single radiation source and a group of "n" in-phase radiation sources. The intensity of the acoustic

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Publication Date
Sun Dec 02 2012
Journal Name
Baghdad Science Journal
Synthesis, spectroscopic study of Pt (IV), Au (III), Rh(III),Co(II) and V (IV) complexes with sodium[5-(p-nitro phenyl) -/4- phenyl-1,2,4-triazole-3-dithiocarbamato hydrazide] and cytotoxicity assay on rhabdomyosarcoma cell line of heavy metals
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All the prepared metal complexes of Pt (IV), Au(III), Rh (III), Co (II) and V(IV) with new ligand sodium [5-(p-nitro phenyl)-/4-phenyl-1,2,4-triazole-3-dithiocarbamato hydrazide] (TRZ.DTC) have been synthesized and characterized in solid state by using flame atomic absorption, elemental analysis C.H.N.S, FT-IR ,UV-Vis Spectroscopy, conductivity and magnetic susceptibility measurements. The nature of the complexes formed in ethanolic solution has been studied following the molar ratio method also was studied stability constant and found to be stable in molar ratio1:1 of VL (IV) and CoL(II) while Pt(IV), Au(III) and Rh(III) complexes stable in molar ratio 1:2 as well as the molar absorptivity for these complexes were calculated. From the prev

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Publication Date
Sat Jan 30 2021
Journal Name
Iraqi Journal Of Science
A4-Graph of Finite Simple Groups
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Let G be a finite group and X be a conjugacy class of order 3 in G. In this paper, we introduce a new type of graphs, namely A4-graph of  G, as a simple graph denoted by A4(G,X) which has X as a vertex set. Two vertices,  x and y, are adjacent if and only if  x≠y and  x y-1=y x-1. General properties  of the A4-graph as well as the structure of A4(G,X) when G@ 3D4(2) will be studied.

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Publication Date
Wed Feb 29 2012
Journal Name
Al-khwarizmi Engineering Journal
Natural Convection in Trapezoidal Enclosure Heated Partially from Below
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Natural convection in a trapezoidal enclosure with partial heating from below and symmetrical cooling from the sides has been investigated numerically. The heating is simulated by a centrally located heat source on the bottom wall, and four different values of the dimensionless heat source length, 1/5, 2/5, 3/5, 4/5 are considered. The laminar flow field is analyzed numerically by solving the steady, two-dimensional incompressible Navier-Stokes and energy equations. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations  discretized by finite volume method; body fitted coordinates are used to represent the trapezoidal enclosure, and grid generatio

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Publication Date
Fri Mar 01 2019
Journal Name
Al-nahrain Journal Of Science
Effect of Active Galactic Nuclei (AGN) on the Photometric and Morphologic Properties of NGC 4414 and NGC 4369 Spiral Galaxies
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The purpose of this work is to clarify the effect of the Active Galactic Nucleus (AGN) on the properties of the galaxy. A photometric study of two galaxies by surface optical measurements techniques and by using'griz filters' was performed. The scientific material that used in this work was obtained from ''SLOAN DIGITAL SKY SURVEY'' (DR7), a fuzzy color, contour maps, photometric parameters, and color indices were studied by using surface photometric technique. The work was done by Ellipse task in IRAF (Image Reduction and Analysis Facility) software from the National Optical Astronomy Observatory (NOAO).

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Publication Date
Sun Oct 22 2023
Journal Name
Iraqi Journal Of Science
Brain Tumor Detection of Skull Stripped MR Images Utilizing Clustering and Region Growing
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Brain tissues segmentation is usually concerned with the delineation of three types of brain matters Grey Matter (GM), White Matter (WM) and Cerebrospinal Fluid (CSF). Because most brain structures are anatomically defined by boundaries of these tissue classes, accurate segmentation of brain tissues into one of these categories is an important step in quantitative morphological study of the brain. As well as the abnormalities regions like tumors are needed to be delineated. The extra-cortical voxels in MR brain images are often removed in order to facilitate accurate analysis of cortical structures. Brain extraction is necessary to avoid the misclassifications of surrounding tissues, skull and scalp as WM, GM or tumor when implementing s

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Publication Date
Sun Dec 06 2015
Journal Name
Baghdad Science Journal
New Operational Matrices of Seventh Degree Orthonormal Bernstein Polynomials
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Based on analyzing the properties of Bernstein polynomials, the extended orthonormal Bernstein polynomials, defined on the interval [0, 1] for n=7 is achieved. Another method for computing operational matrices of derivative and integration D_b and R_(n+1)^B respectively is presented. Also the result of the proposed method is compared with true answers to show the convergence and advantages of the new method.

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Publication Date
Sat Dec 30 2023
Journal Name
Iraqi Journal Of Science
Derivable Maps of Prime Rings
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Our active aim in this paper is to prove the following Let Ŕ be a ring having an
idempotent element e(e  0,e 1) . Suppose that R is a subring of Ŕ which
satisfies:
(i) eR  R and Re  R .
(ii) xR  0 implies x  0 .
(iii ) eRx  0 implies x  0( and hence Rx  0 implies x  0) .
(iv) exeR(1 e)  0 implies exe  0 .
If D is a derivable map of R satisfying D(R )  R ;i, j 1,2. ij ij Then D is
additive. This extend Daif's result to the case R need not contain any non-zero
idempotent element.

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