Rare-earth metal oxides (REMOs) exhibit distinctive properties, among which cerium oxide (CeO2) displays numerous industrial, technological, and medical applications. However, the inclusion of hafnium (Hf) at the cerium (Ce) site to form the (Ce1-ₓHfₓO2) lattice system at a concentration of x = 0.25 would have an impact on enhancing the physical properties of the simulated configuration. Density functional theory (DFT) was used to perform the calculations, supported by the Hubbard correction factor (U). The generalized gradient approximation (GGA-PBE) was employed to analyze the electronic, structural, optical, and mechanical properties at hydrostatic pressures (P = 0, 25, 50, 75, and 100 GPa). The ground state geometry of the pristine fluorite CeO2 corresponds to 5.438 Å, signifying an excellent agreement with the available published literature. The calculated lattice parameter of Ce0.75Hf0.25O2 is diminished to 5.327 Å as compared with CeO2. Furthermore, CeO2 exhibits a semiconductor character with a direct band gap of 3.134 eV, while the band gap of the Ce0.75Hf0.25O2 system was reported to be 3.073 eV, demonstrating slight degradation. However, under pressure, the results demonstrate a gradual increment in the band gap energy of Ce0.75Hf0.25O2 until reaching 3.861 eV at 100 GPa. Furthermore, the thermodynamic feasibility was investigated via the chemical potential approach. The pressure-dependent optical properties were extensively discussed of Ce0.75Hf0.25O2, demonstrating enhanced optical properties in the ultraviolet (UV) region, motivating its suitable utility for optoelectronic memristors and other photonic applications.
The most used material in the world after water is concrete, which depends mainly on its manufacture of cement leading to the emission of carbon dioxide (CO2), flying dust, and other greenhouse gasses (GHGs) resulting in pollution of the atmosphere. The emission of CO2 from cement production is approximately 5% of the global anthropogenic CO2. This research focuses on investigating the amount of CO2 emission from the Iraqi General Cement Company plants includes the cement factories of Kirkuk, Al-Qa’em, Fallujah, and Kubaisa, using the GHGs Protocol Measures Program (specifically cement based-method).
Controlling cost in construction projects is an essential issue. This study investigates the most critical problems that cause weakness in cost control in Iraqi construction projects. The quantitative technique was used by conducting a survey directed to professionals who work on construction projects. One hundred and sixty-four questionnaire forms were distributed to private sector companies, government companies, and government institutions, and the responses were subjected to the required statistical analysis. The results indicate that the most influential factors are the weakness in keeping up with the use of modern concepts, methods, and technologies, the delay in receiving the amounts due for work done from the owner, fluctuat
... Show MoreIn this work, As60Cu40-xSex thin films were synthesized, and the pulsed laser deposition method was used to study the effected partial replacement of copper with selenium. The electrical characteristics and optical characteristics, as indicated by the absorbance and transmittance as a function of wavelength were calculated. Additionally, the energy gap was computed. The electrical conductivity of the DC in the various conduction zones was calculated by measuring the current and voltage as a function of temperature. Additionally, the mathematical equations are used to compute the energy constants, electron hopping distance, tail width, pre-exponential factor, and density of the energy states in variation zones (densities of the energ
... Show MoreThe importance of research is to be considered by highlighting the tax policy in Iraq which extended for successive measurement of the amount of tax receipts for respective periods, the research problem represents security, economic and political issues that Iraq suffered which were very difficult since Nineties of the last century until now that led to a lake of clarity in tax policy trends, volatility in it and finally reflected on the tax revenues increase or decrease. One of the main recommendations of the research is: (The necessity to develop a deliberate strategy for tax policy in Iraq which should take into account financial, economic, and social goals in appropriate way).
Nasiriya field is located about 38 Km to the north – west of Nasiriya city. Yammama, a giant lower cretaceous reservoir in Nasiriya field which is lithologically formed from limestone. Yammama mainly was divided into three main reservoir units YA, YB1, YB2 and YB3 and it is separated by impermeable layers of variable thickness. An accurate petro physical evolution of the reservoir is of great importance perform an excellent geological model so that four petro physical properties which are shale volume, porosity, water saturation and permeability was re-evaluated. The volume of shale was calculated using the density and neutron logs (VSH-DN) rather than using gamma ray log because of presence a uranium content in the formation that make
... Show MoreCurrently, there is no established of e-waste treatment in Thi- Qar province, while their creating is increasing every year. It has been well- known that e-waste is a source of environmental degrading and their placement in landfills increases the irreversible climate change. A research model has been developed to link three components: coercive pressure, normative influence, and mimicry, then study their effect on e-waste adopt and continuance intentions. The model was validated using data collected from a field survey of 92 managers of small enterprises in Thi-Qar province. A questionnaire was developed to collect data. It contains five major variables, exemplify by fourteen items. Als
... Show MoreDue to the remarkable progress in photovoltaic technology, enhancing efficiency and minimized the costs have emerged as global challenges for the solar industry. A crucial aspect of this advancement involves the creation of solar cell antireflection coating, which play a significant role in minimizing sunlight reflection on the cell surface. In this study, we report on the optimization of the characteristics of CeO2 films prepared by pulsed laser deposition through the variation of laser energy density. The deposited CeO2 nanostructure films have been used as an effective antireflection coating (ARC) and light-trapping morphology to improve the efficiency of silicon crystalline solar cell. The film’s thickness increases as laser fluence i
... Show MoreThe appearance of Mixed Mode Oscillations (MMOs) and chaotic spiking in a Light Emitting Diode (LED) with optoelectronic feedback theoretically and experimentally have been reported. The transition between periodic and chaotic mixed-mode states has been investigated by varying feedback strength. In incoherent semiconductor chaotically spiking attractors with optoelectronic feedback have been observed to be the result of canard phenomena in three-dimensional phase space (incomplete homoclinic scenarios).
Noor oil field is one of smallest fields in Missan province. Twelve well penetrates the Mishrif Formation in Noor field and eight of them were selected for this study. Mishrif formation is one of the most important reservoirs in Noor field and it consists of one anticline dome and bounded by the Khasib formation at the top and the Rumaila formation at the bottom. The reservoir was divided into eight units separated by isolated units according to partition taken by a rounding fields.
In this paper histograms frequency distribution of the porosity, permeability, and water saturation were plotted for MA unit of Mishrif formation in Noor field, and then transformed to the normal distribution by applying the Box-Cox transformation alg
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