This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.
A new, effective, simple and inexpensive method was developed for determination the amounts of Ciprofloxacin HCl in solutions and in tablets by spectrophotometry and turbidity using sodium tungstate as reagent. Also, in this paper comparison between two techniques was conducted. The reaction between the Ciprofloxacin HCl and reagent in acidic media formed a yellowish white complex. Chemical and physical conditions have been investigated. The Linear range for spectroscopic and turbidimetric techniques were (0.05-1.25) and (0.05-3.0) mmol.L-1 with correlation coefficients (0.9956) and (0.9941) respectively. The limits of detection were 7×10-5 and 5×10-5 mol.L-1. The proposed method is good alternative for determination of Ciprofloxacin H
... Show MoreBackground:
Comparative morphological study has been treated for two species of the genus Chaenorhinum (D.C.) Richb., These species were: 1. Chaenorhinum calycinum 2. Chaenorhinum rubrifolium (Robill. & cast. Ex Lam. & DC.) Fourr. The genus belong to the family Scorphulariaceae. Morphological characters has been studies for: root, stem, leaves, flowers (calyx, corolla, androcium including filaments and anthers, gynocium including ovary, style and stigma), fruits and seeds also has been characterized. Key for there two species presented using some quantitative characters. Other characters like shape of fruits and seeds were used too, and they were of a useful taxonomic value
The process of evaluating data (age and the gender structure) is one of the important factors that help any country to draw plans and programs for the future. Discussed the errors in population data for the census of Iraqi population of 1997. targeted correct and revised to serve the purposes of planning. which will be smoothing the population databy using nonparametric regression estimator (Nadaraya-Watson estimator) This estimator depends on bandwidth (h) which can be calculate it by two ways of using Bayesian method, the first when observations distribution is Lognormal Kernel and the second is when observations distribution is Normal Kernel
... Show MoreThis research attempts to find the association between single nucleotide polymorphism (SNP) of IL2+166 gene (rs2069763) and type 2 diabetes mellitus (T2DM) in a sample of Iraqi patients. A total of 44 patients and 55 apparently healthy volunteers were genotyped for the SNP using polymerase chain reaction test. Three genotypes (GG, GT, and TT) corresponding to two alleles (G and T) were found to have SNP. Both study groups’ genotypes had a good agreement for the analysis of Hardy-Weinberg Equilibrium. The results revealed increased frequencies between the observed and expected GG and TT genotypes and IL2+166 SNP T allele in T2DM patients (40.9 vs. 40.0 %; OR = 1.04; 95% CI, 0.47 - 2.31)
... Show MoreThe research aims to know the traits or characteristics of woman in terms of her external
appearance, motives for her behavior, feelings, mood and ability.
It, moreover, seeks woman’s relationship with others as it is presented by the Iraqi
satirical television show “ State of Melon “.
The researcher adopted for that survey approach using the method of content analysis
to study the research sample represented by “ State of Melon “ show which was
exposed through the screen of a group of channels:
“Hona Baghdad Satellite Channel, then Asia Satellite Channel, Dijla Satellite Channel,
and UTV Satellite Channel.”For this, the researcher used Margaret Gallagher’s Model to analyze the image of
woman in
The antibacterial activities of some nanoparticles, makes them attractive as a new agents against pathogenic bacteria. In this research, the antimicrobial effects of Titanium dioxide-nano-particles against seven bacterial isolates (E.coli, Enterobacter aerogenes, Pseudomonas alcaligenes, Aeromonas veronii, Aeromonas hydrophila, Serratia marcescens and Staphylococcus aureus) being isolated from different Baghdad water purification stations investigated. The physiochemical characters, which influence the quality of the drinking water for the air and water, demonstrated.The characterization of nanoparticles investigated by using Scanning Electrone Microscope, FTIR, and UV-Visible Spectrophotometer. The activity of different concentration of
... Show MoreThis paper presents an experimental and theoretical analysis to investigate the two-phase flow boiling heat transfer coefficient and pressure drop of the refrigerant R-134a in the evaporator test section of the refrigeration system under different operating conditions. The test conditions considered are, for heat flux (13.7-36.6) kW/m2, mass flux (52-105) kg/m2.s, vapor quality (0.2-1) and saturation temperature (-15 to -3.7) ˚C. Experiments were carried out using a test rig for a 310W capacity refrigeration system, which is designed and constructed in the current work. Investigating of the experimental results has revealed that, the enhancement in local heat trans
... Show MoreRecently, in the last years, the world interested with Ecosystem is increased, and
that is interrelation with global atmospherically, by the existence followed
continuous animate variables, that is immediately influence at ecosystem nature by
inspection systems process such as satellite imagery or aerial photographs, that can
determination the wetland regions which aid fulfillment balance globe ecosystem. In
this study a determination of wetland regions in IRAQ, was done for Anbar
province, because many of regions Saturated with water or sponge and aquatic of
plant, additionally, existence metrology factors that significant role were depended
to be as important factor to define the wetland regions as temperatures,