Seminars 2017-2018
Hossein A. Mohammad, 09/06/2018
Abstract:
In this study, we investigate influences of fourth generation quarks on the total branching ration and the single lepton polarization asymmetry for Bs → φl+l− decay. Calculating the new Wilson coefficients in effective Hamiltonian show that the total branching ratio and the lepton polarization as well as the combined lepton asymmetries are sensitive to the existence of the fourth generation, therefore it can be an effective way to identify the new generation quarks in high energy physics laboratories.
Hossein A. Mohammad, 09/06/2018
Abstract:
This work investigate the influence of the fourth generation of quarks on the CP asymmetry in Bs → φl+l− Decay. This new quarks changes the values of the Wilson coefficients C7(µ), C9(µ) and C10(µ) via virtual exchange of the fourth generation up type quark t'. Taking the |VtbV∗ts| ∼{0.01 − 0.03} with phase {60, 90, 120} , which is consistent with the b → sl+l− rate and the Bs mixing parameter ∆mBs both (µ, τ) channels the CP-asymmetries are quite sensitive to the 4th generation quarks mass and mixing parameters. Hence, studying CP asymmetry for B → φl+l− decay with newWilson coefficients can serve as an effective way to identify the new generation quarks (t', b') in high energy physics laboratories.
Ali M. Mohammad, 20/05/2018
Abstract:
A series of Cr-substituted cobalt ferrite nanoparticles CoCrxFe2-xO4 with (0.0 ≤ x ≤ 1.0 with an interval of 0.2), have been synthesized using citrate-gel auto combustion method, the as burnt powders calcined at 600, 700, and 800 ˚C for 3h, and the powders that calcined at 800 ˚C were pressed into a disk shape compacts and sintered in air at 900 ˚C for 3h to study the dielectric properties. The structural properties of all prepared samples was carried out by X-ray diffraction (XRD), the results confirm the formation of spinel cubic structure and revealed the secondary phase with increasing Cr3+ contents 0.4≤ x ≤ 1.0 for the sample that calcined at 600 and 700 ˚C, whereas the samples that calcined at 800 ˚C showed formation of spinel cubic structure with single phased for all Cr-substituted. Moreover, the substitution of Cr3+ ions caused a significant reduction in crystallite size. The FE-SEM image results show the some agglomerated of spherical and polyhedral shape morphology with fine size in the range of (44-68 nm). The dielectric parameters such as dielectric constant, dielectric loss (angle and factor) and ac conductivity for all samples were studied as a function of frequency at room temperature by using LCR meter. Variation of dielectric properties at frequencies from 50Hz to 1MHz has been explained on the basis of the Koop’s theory, Maxwell-Wagner polarization process, and hoping of electrons. All dielectric properties showed a normal behavior with increasing the frequency.
Ali M. Mohammad, 20/05/2018
Abstract:
A series of magnesium-substituted cobalt ferrite nanoparticles Co1-xMgxFe2O4 (0.0 ≤ x ≤ 1.0, step 0.2), have been synthesized using sol–gel auto-combustion method. The powders calcined at 600, 700, and 800 ˚C for 3h. Various characterization methods were used to investigate the prepared powders such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and vibrating sample magnetometer (VSM). The XRD patterns of the synthesized samples confirm the formation of single phase spinal structured nanoparticles. FE-SEM image results show some agglomerated of spherical and polyhedral shape morphology. Moreover, the average crystallite size was found to be ranging from (55.146-68.434nm). Saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) decreases with increase in Mg substitution as indicated by VSM at room temperature. Both the structural and magnetic properties of Mg-Co ferrite nanoparticles depend upon Mg2+ ions substitution.
Adnan Mahmood Saleh, 20/05/2018
Abstract:
In this work, tin oxide SnO2 thin films were deposited on glass substrates by APCVD technique. Oxygen gas flow rates (4NL/h) is used with various substrates temperature (300, 400, 500, 550, 600 and 650 ̊C) with deposition time of 30 min. The XRD analysis revealed that SnO2 deposited at 400 ̊C and flow rate (4 NL/h) give the smallest crystallite size. While the largest crystallite size is obtained at 500 ̊C. FE-SEM images confirmed the results of the grain size calculated from the XRD analysis. The average micro strain were analyzed by Williamson–Hall methods. Uv-vis spectroscopy measurements showed that the band gap values are in the range (3.27-4.12eV).
Adnan Mahmood Saleh, 20/05/2018
Abstract:
Thin films of tin oxide were deposited on glass substrates at temperature 400°C under various flow rates of oxygen using atmospheric pressure chemical vapor deposition method (APCVD). The synthesized thin films were characterized by X-Ray Diffraction (XRD), UV-VIS spectrophotometer and Field Emission Scanning Electron Microscopy (FE-SEM) to study the structural and optical properties. The results of X-ray diffraction showed that the crystallite size in these thin films were varied as a result of varying deposition conditions, and the average crystalline size was found using Scherrer equation which showed decreasing with decreasing the flow rate within (4-8 NL/h). FE-SEM images of the films showed that the particle size for two samples were 24.2 and 32.3 nm which corresponding to flow rates 4 and 5 NL/h respectively. The optical band gaps of the films were in the rang (3.72-4.1 eV).
Shakhawan Hassan Ali, 16/05/2018
Abstract:
Liquid crystals are a special part of a mature display technology, despite other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors. Recently, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i) addition of nanomaterials can modify the properties of the liquid crystal; (ii) novel functionalities could be added to the liquid crystal; and (iii) the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research has been carried out on thermotropic systems. Here I explain the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids.
Jamil Assad Zahed, 16/05/2018
Abstract:
The emergence of “life as we know it” requires stars for two reasons. Stars are needed to produce the heavy elements (carbon, oxygen and so on, up to iron) out of which rocky planets and the molecules of life are made. Stars also provide a heat source for powering the chemistry of life on the surface of their planets. Each star is surrounded by a habitable zone where the surface temperature of a planet allows liquid water to exist.
Salar Ghader Hassan, 14/05/2018
Rezhna Mhammed Kuekha, 2/5/2018
Abstract:
Ultraviolet and visible spectrometers have been in general use for the last 35 years and over this period have become the most important analytical instrument in the modern day laboratory. In many applications other techniques could be employed but none rival UV-Visible spectrometer for its simplicity, versatility, speed, accuracy and cost-effectiveness.
Rezhna Mhammed Kuekha, 2/5/2018
Abstract:
Effect of Polyvinyl Alcohol (PVA) film thickness on some optical parameters Transparent films of Polyvinyl Alcohol with different thicknesses were made by applying solution casting technique at a temperature of (70°C). The optical absorption and transmission spectra were accomplished for all samples at room temperature over the wavelength region (190-1100) nm. Studying the effect of film thickness, which is measured with micrometer with an error not exceeding (5%), on optical parameters gives an indication that all these parameters are affected with thickness. The experimental results for Polyvinyl Alcohol films show that the optical energy gap decreases by the increasing of film thickness. The absorption coefficient, refractive index, extinction coefficient and real and imaginary parts of dielectric constant are increased by increasing the film thickness.
Rezhna Mhammed Kuekha, 2/5/2018
Abstract:
Ionizing Radiation contains sufficient electromagnetic energy to strip atoms and molecules from the tissue and alter chemical reactions in the body (converting molecules totally or partly into ions). X-Rays and Gamma rays are two forms of ionizing radiation. These rays are known to cause damage, which is why a lead vest must be worn when X-rays are taken of our bodies, and heavy shielding surrounds nuclear power plants. spectrum is considered non-ionizing Electromagnetic Radiation (EMR), with energy levels below that required for effects at the atomic level.
Kamaran S. Rasool, 1/5/2018
Abstract:
The basic function of the Demultiplexer (DEMUX): 1) The typical application of a DEMUX, 2) A 1-to-4 DEMUX design with Small Scale Integration (SSI), 3) A 1-to-4, 1-to-8, & 1-to-16 Medium Scale Integration (MSI) DEMUX.
Kamaran S. Rasool, 1/5/2018
Abstract:
This presentation will demonstrate: 1) The basic function of the Multiplexer (MUX), 2) The typical application of a MUX, 3) A 4-to-1 MUX designed with Small Scale Integration (SSI), 4) A 4-to-1, 8-to-1, & 16-to-1 Medium Scale Integration (MSI) MUX.
Shakhawan Hassan Ali, 1/5/2018 and
Abstract:
Liquid crystals are a special part of a mature display technology, despite other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors. Recently, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i) addition of nanomaterials can modify the properties of the liquid crystal; (ii) novel functionalities could be added to the liquid crystal; and (iii) the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research has been carried out on thermotropic systems. Here I explain the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids.
Kamaran S. Rasool, 24/4/2018
Abstract:
A) The basic function of transistor is amplification. The process of raising the strength of weak signal without any change in its general shape is referred as faithful amplification. For faithful amplification it is essential that:-
Emitter-Base junction is forward biased
Collector- Base junction is reversed biased
Proper zero signal collector current
B) The second application is (transistor switch), C) If the transistor is not biased properly, it would work inefficiently and produce distortion in output signal.
Kamaran S. Rasool, 23/4/2018
Abstract:
Unlike resistors, which enforce a linear relationship between voltage and current, transistors are non-linear devices. They have four distinct modes of operation, which describe the current flowing through them. (When we talk about current flow through a transistor, we usually mean current flowing from collector to emitter of an NPN.)
The four transistor operation modes are:
Saturation – The transistor acts like a short circuit. Current freely flows from collector to emitter.
Cut-off – The transistor acts like an open circuit. No current flows from collector to emitter.
Active – The current from collector to emitter is proportional to the current flowing into the base.
Reverse-Active – Like active mode, the current is proportional to the base current, but it flows in reverse. Current flows from emitter to collector (not, exactly, the purpose transistors were designed for).
Salar Kareem Fatah, 16/01/2018
Abstract:
In this study, a hydrothermal method of synthesizing Hydroxyapatite (HAp) by heating a precipitate, formed by mixing Ca (NO3) 2. 4 H2O and (NH4) 2 HPO4 with distilled water, in hydrothermal reaction 200 0C for 24 hrs has been described. After that, the characterisation techniques were used such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Selected Area of Electron Diffraction (SAED) and Energy-Dispersive X-ray spectroscopy (EDX). Results indicated that the pure (HAp) nanostructure with uniform morphologies, controllable size, nano-dispersion and narrow-size distribution in diameter were synthesized successfully, and the synthesized powders can be used extensively in medicine, dentistry for implant synthesis and for scientific research.
Salar Kareem Fatah, 16/01/2018
Abstract:
In this study, the basic understanding of precipitation method to synthesis of Zinc Oxide nanopowders has been demonstrated. The synthesised nanopowders were formed by mixing Zn (O2CCH3)2 (H2O)2, diethylene glycol (DEG) and deionized water, then the mixed solution was heated at two different temperatures 140 0C and 180 0C for 2 hours. The synthesised nanopowders have been studied by different characterisation techniques as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and Energy-Dispersive X-ray spectroscopy (EDX). Results demonstrated that the pure Zinc oxide nanopowders with low trace elements, with uniform morphology, controllable size and narrow-size distribution in diameter were achieved. The synthesized nanopowders can be used as active filler for rubber and plastic, catalyst and gas sensor.
Salar Kareem Fatah, 16/10/2017
Abstract:
The Mars 2020 rover mission is part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet. The Mars 2020 mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars. The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. The Mars 2020 rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a "cache" on the surface of Mars. A future mission could potentially return these samples to Earth. That would help scientists study the samples in laboratories with special room-sized equipment that would be too large to take to Mars. The mission also provides opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions to Mars. These include testing a method for producing oxygen from the Martian atmosphere, identifying other resources (such as subsurface water), improving landing techniques, and characterizing weather, dust, and other potential environmental conditions that could affect future astronauts living and working on Mars.