The paper presents an overview of theoretical aspects of small radio telescope antenna parameters. The basic parameters include antenna beamwidth, antenna gain, aperture efficiency, and antenna temperature. These parameters should be carefully studied since they have vital effects on astronomical radio observations. The simulations of antenna parameters were carried out to assess the capability and the efficiency of small radio telescopes to observe a point source at a specific frequency. Two-dimensional numerical simulations of a uniform circular aperture antenna are implemented at different radii. The small diameter values are chosen to be varied between (1-10) m. This study focuses on a small radio telescope with a diameter of 3 m since this telescope is very common in the world. The simulated results of this study illustrated that the power pattern of a 3 m antenna has a half-power beamwidth of approximately 5 degrees. Also, the maximum peak antenna temperature is estimated to be more than 3000 K. All of these results were in good agreement with observations of the neutral hydrogen spectral line at the frequency of 1.42 GHz using a small radio telescope.
Many important archaeological sites in Iraq still need to be preserved. Some of these sites were subjected to destruction and negligence. So, exploring these sites represents a priority for its protection. A 2D Electrical Resistivity Imaging (ERI) as a non-invasive geophysical survey method was implemented at a part of the Borsippa archaeological site near Babylon to search for the subsurface archaeological artefacts/structures. Electrical resistivity measurements were carried out using a Dipole-Dipole array. Steps were taken to process and filter using Horizontal profiles, forward modelling, and 2D inverse models to analyze the resistivity measurements. The ERI inversion results show that the superficial conductive zone produced va
... Show MoreObjectives: The current study aims to evaluate parents' knowledge towards diabetes mellitus (type I); to identify the association between parents' knowledge and their demographic characteristics; and to identify the association between parents' knowledge and demographic characteristics of their children. Methodology: Descriptive study carried out during the period from January to April 2015 on purposive sample of 100 parents with their children with diabetes mellitus who attending diabetes and endocrine treatment center. An evaluation tool is constructed by the researcher based on previous literature regarding
Background: Prolapsed intervertebral disc is an important and common cause of low backache. MRI has now become universally accepted investigation for prolapsed intervertebral disc. We, however, regularly come across situations, when MRI shows diffuse disc bulges, even at multiple levels, which cannot be correlated clinically and when such cases are operated, no significant disc prolapse is found resulting in negative exploration. Objective: To evaluate the role of M.R.I. finding not only for diagnosis of disc herniation at lumbar region but also for localization the level of herniation Methods: A prospective study on seventy five symptomatic low backache and MRI confirmed prolapsed intervertebral disc patients at lumbo-sacral region were op
... Show MoreIn this study, silver-tungsten oxide core–shell nanoparticles (Ag–WO3 NPs) were synthesized by pulsed laser ablation in liquid employing a (1.06 µm) Q-switched Nd:YAG laser, at different Ag colloidal concentration environment (different core concentration). The produced Ag–WO3 core–shell NPs were subjected to characterization using UV–visible spectrophotometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive spectroscopy, electrical analysis, and photoluminescence PL. The UV–visible spectra exhibited distinct absorption peaks at around 200 and 405 nm, which attributed to the occurrence of surface Plasmon reson
NH3 gas sensor was fabricated based on deposited of Functionalized Multi-Walled Carbon Nanotubes (MWCNTs-OH) suspension on filter paper substrates using suspension filtration method. The structural, morphological and optical properties of the MWCNTs film were characterized by XRD, AFM and FTIR techniques. XRD measurement confirmed that the structure of MWCNTs is not affected by the preparation method. The AFM images reflected highly ordered network in the form of a mat. The functional groups and types of bonding have appeared in the FTIR spectra. The fingerprint (C-C stretch) of MWCNTs appears in 1365 cm-1, and the backbone of CNTs observed at 1645 cm-1. A homemade sensi
... Show MoreExperimental densities, viscosities η, and refractive indices nD data of the ternary ethanol+ n-hexane + 3-methyl pentane system have been determined at temperatures 293.15,303.15 and 313.15 K and at atmospheric pressure then these properties were calculated theoretically by using mixing rules for densities, viscosities and refractive indices .After that the theoretical data and the experimental data were compared due to the high relative errors in viscosities an equation of viscosity was proposed to decrease the relative errors.
A total of 48 experiments were conducted to investigate the impact of slit weir dimensions and locations on the maximum scour depth and scour area created upstream. The slit weir model was a 110 mm slit opening, and it was installed at the end of the working section in a laboratory flume. The flume was 10.0 m long, 30 cm wide, 30 cm deep, and almost middle. It includes a 2 m working section with a mobile bed with 110 mm in thickness. In the mobile bed, two types of nonuniform sand (with a geometric standard deviation of 1.58 and 1.6) were tested separately. The weir dimensions and location were changed with flow rates. Then dimensions of the slit weir were changed from 60 x 110 mm to 60 x 70 mm (width x height), while th
... Show MoreThe research aims to determine the impact of employees’ retention strategy on organizational memory. This research is historical, descriptive, and analytical. The sample consists of 158 faculty members in five private colleges in Baghdad. The technique used to analyze the data is SEM (Structural Equation Modeling), and SPSS (Statistical Package for the Social Sciences). The research concludes that the employees retaining strategy plays a vital role in retaining employees and hence maintains organizational memory. The findings and recommendations of this research assure the administrations of private colleges that employees retention strategy play a vital role in retaining its employee and hence maintains organizational memory. T
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