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 research aims to shed light on the obstacles that hinder the use of taxpayers' commercial books covered by provisions of the amended commercial book-keeping system No. 2 of 1985 and ways to address these obstacles. On this basis, the main null hypothesis was formulated that there is no statistically significant relationship between the obstacles to the adoption of the commercial books and taxable income.
The research data were collected on the base of three applied case studies of registered taxpayers in the General Commission of Taxes, GCT, together with the use of a questionnaire distributed to a sample of taxpayers ( companies ). The collected data were analyzed, the result were presented and the hypothesis was
... Show MoreThe self-evident truth existing in today's business environment is the continuity of change and its continuity and turmoil, also its increase over time as it is more abundant, abundant, wide and complex than ever before, and it is the dominant feature in the business environment, as different organizations and operating units can find themselves shifting from the top to the bottom. And then it requires its departments to strive to adapt to these rapid and turbulent shifts and changes by bringing about a series of organizational and adaptive changes that are not limited to one organizational aspect only but rather include all organizational components. Accordingly, this research came to determine the readiness of public organizations to chan
... Show MoreThe health care provided by health institutions and all kinds suffers from many problems, and since the health services provided are related to human life, it is necessary to shed light on this activity and identify the causes of these problems. This research aims to Definition of health institutions (hospitals) Performance audit of these institutions according to the latest indicators, which are the standards of health accreditation for hospitals, specifically the basic standards issued by the Health Care Accreditation Council (HCAC) to reach the level of performance and Knowledge of Constraints that lead to in an acceptable manner consistent with the approved standards. In theoretical and practical study, a number of conclusions were r
... Show MoreFilms of PMMA and copper sulphate doped PMMA have been prepared by casting method. Absorbance and transmittance spectra were recorded in the wavelength range (300-900) nm in order to calculate, single oscillator energy, dispersion energy, average oscillator strength, the refractive index at infinite wavelength, M-1 and M -3 moments of the optical spectra, it was found that all these parameters were effected by doping.
This research dealt with the subject of auditing bank credit risks in accordance with international auditing standards and aims to develop procedures and design a credit risk audit program in accordance with international auditing standards and demonstrate their impact on the truth, truthfulness and fairness of financial statements and on their overall performance and continuity in the banking sector Its importance lies in relying on international auditing standards to assess and measure bank credit risk and its impact on the financial situation as well as the ability to predict financial failure. A set of conclusions have been reached, the most important of which is that the bank faces difficulties in measuring credit risk in accordance
... Show MoreAbstract: In this paper, a U-shaped probe with a curvature diameter of half a centimeter was implemented using plastic optical fibers. A layer of the outer shell of the fibers was removed by polishing to a D-section. The sensor was tested by immersing it in a sodium chloride solution with variable refractive index depending on solution concentrations ranging from 1.333 to 1.363. In this design, the sensor experienced a decrease in its intensity as the concentration of the solution increased. The next step The sensor was coated with a thin layer of gold with a thickness of 20 nm, and the sensor was tested with the same solutions which resulted in a shift in wavelengths where the shift in wavelength was 5.37 nm and sensiti
... Show MoreThis research aims to investigate the color distribution of a huge sample of 613654 galaxies from the Sloan Digital Sky Survey (SDSS). Those galaxies are at a redshift of 0.001 - 0.5 and have magnitudes of g = 17 - 20. Five subsamples of galaxies at redshifts of (0.001 - 0.1), (0.1 - 0.2), (0.2 - 0.3), (0.3 - 0.4) and (0.4 - 0.5) have been extracted from the main sample. The color distributions (u-g), (g-r) and (u-r) have been produced and analysed using a Matlab code for the main sample as well as all five subsamples. Then a bimodal Gaussian fit to color distributions of data that have been carried out using minimum chi-square in Microsoft Office Excel. The results showed that the color distributions of the main sample and
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