Simple Floating Voltage-Controlled Memductor Emulator for Analog Applications

The topic of memristive circuits is a novel topic in circuit theory that has become of great importance due to its unique behavior which is useful in different applications. But since there is a lack of memristor samples, a memristor emulator is used instead of a solid state memristor. In this paper, a new simple floating voltage-controlled memductor emulator is introduced which is implemented using commercial off the shelf (COTS) realization. The mathematical modeling of the proposed circuit is derived to match the theoretical model. The proposed circuit is tested experimentally using different excitation signals such as sinusoidal, square, and triangular waves showing an excellent matching with previously reported simulations

Path dependence and universal health coverage: The case of Egypt

Universal health coverage (UHC) is the big objective in health policy which several countries are seeking to achieve. Egypt is no different and its endeavors to attain UHC have been going on since the 1960s. This article discusses the status of UHC in Egypt using theories of political science and economics by analyzing the historical transformations in the Egyptian health system and its institutional settings. This article then specifically examines the path dependence theory against the sociopolitical background of Egypt and assesses any pattern between the theory and the current UHC status in Egypt. The important finding of this analysis is that the health policies and reforms in Egypt have been significantly influenced and limited by its historical institutional structure and development. Both the health policies and the institutional settings adopted a dependent path that limited Egypt’s endeavors to achieve the universal coverage. This dependent path also yielded many of the present-day challenges as in the weaknesses of the healthcare financing system and the inability to extend health coverage to the poor and the informal sector. These challenges subsequently had a negative impact on the accessibility of the healthcare services

Power Dissipation of Memristor-Based Relaxation Oscillators

Recently, many reactance-less memristive relaxation oscillators were introduced, where the charging and discharging processes depend on memristors. In this paper, we investigate the power dissipation in different memristor based relaxation oscillators. General expressions for these memristive circuits as well as the power dissipation formulas for three different topologies are derived analytically. In addition, general expressions for the maximum and minimum power dissipation are calculated. Finally, the calculated expressions are verified using PSPICE simulations showing very good matching

Corrosion Inhibition of Zinc Using Some Phenylthiazole Derivatives in Hydrochloric acid Solutions

The inhibitive action of some phenylthiazole derivatives namely: 2-acetylamino-5-p-bromophenylazo-4-phenylthiazole (BPT), 2-acetylamino-5-p-methylphenylazo-4-phenylthiazole (MPT), 2-acetylamino-5-p-methoxyphenylazo-4-phenylthiazole (XPT) and 2-acetylamino-5-p-nitrophenylazo-4-phenylthiazole (NPT), on zinc corrosion in 0.2 M HCl  has been studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS)and electrochemical frequency modulation (EFM) measurements. The results showed that the dissolution rate of zinc decreases with increasing the phenylthiazole derivatives concentration and decreases with raising temperature. Polarization curves indicated that the studied inhibitors act as mixed-type inhibitors. The adsorption of the investigated compounds follows Langmuir adsorption isotherm model. The thermodynamic parameters of adsorption and corrosion processes were determined and discussed.Â

Mentha piperita extract as a natural product for the corrosion inhibition of low carbon steel in a polluted NaCl environment: Chemical, electrochemical and biological studies

The impact of aqueous Mentha piperita extract (MPE) as a corrosion inhibitor for low carbon steel (LCS) in NaCl/Na2S solution has been investigated using chemical and electrochemical techniques to evaluate the protection performance of MPE. ―As the concentration of the extract increased, the protection efficiency (PE) increased, reaching 91.2% at 300 ppm, whereas the increase in temperature favoured to slow decrease‖.The extract has been physically adsorbed on the metal surface according to the Temkin isotherm. Polarization data reveal that this extract acts as a mixed inhibitor. The mechanism of corrosion protection of MPE has been discussed from electrochemical techniques. MPE has been adsorbed on LCS obeying Temkin isotherm. Surface morphology techniques such as scanning electron microscopy (SEM) and atomic force microscopy have been used to demonstrate the creation of a protective coating on the LCS in the presence of MPE. The extract inhibits the bacterial activity of Escherichia coli

Improving the predictive quality of time‐dependent density functional theory calculations of the X‐ray emission spectroscopy of organic molecules

The simulation of x-ray emission spectra of organic molecules using time-dependent density functional theory (TDDFT) is explored. TDDFT calculations using standard hybrid exchange-correlation functionals in conjunction with large basis sets can predict accurate X-ray emission spectra provided an energy shift is applied to align the spectra with experiment. The relaxation of the orbitals in the intermediate state is an important factor, and neglect of this relaxation leads to considerably poorer predicted spectra. A short-range corrected functional is found to give emission energies that required a relatively small energy shift to align with experiment. However, increasing the amount of Hartree-Fock exchange in this functional to remove the need for any energy shift led to a deterioration in the quality of the calculated spectral profile. To predict accurate spectra without reference to experimental measurements, we use the CAM-B3LYP functional with the energy scale determined with reference to a ∆self-consistent field (SCF) calculation for the highest energy emission transition

Biochemical and mineral compositions of six brown seaweeds collected from Red Sea at Hurghada Coast

484-491The biochemical and mineral compositions of six brown seaweeds collected during spring season from Red Sea at Hurghada coast were determined to evaluate their significance in animal nutrition. The results suggested that the highest ash and protein contents were recorded in Padina gymnospora (45.48%) and Sargassum muticum (5.31%), respectively. The carbohydrates content was > 24.0% in the studied seaweeds, while the fat content ranged from 0.11 to 0.27%, and the essential amino acids formed 38.13-42.34% of the total amino acids. Both Padina gymnospora and Turbinaria sp. had the majority of measured phenolic compounds. Also, the studied seaweed species were rich in vitamin B2 (> 105.0 ppm), except Sargassum aspirofolium. The highest/lowest vitamin C content existed in Sargassum muticum (11.76 ppm) and Sargassum aspirofolium (3.96 ppm), respectively. Moreover, the tested seaweeds exhibited high amounts of essential minerals. Therefore, Red Sea brown seaweeds are good food sources for animal nutrition