Modified algae with nano copper oxide (CuO) were used as adsorption media to remove tetracycline (TEC) from aqueous solutions. Functional groups, morphology, structure, and percentages of surfactants before and after adsorption were characterised through Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Several variables, including pH, connection time, dosage, initial concentrations, and temperature, were controlled to obtain the optimum condition. Thermodynamic studies, adsorption isotherm, and kinetics models were examined to describe and recognise the type of interactions involved. Resultantly, the best operation conditions were at pH 7, contact time of 240 min, 5 g/L of dosage, initial concentration of 25 mg/L, and a temperature of 45 °C. The removal percentage of TEC under the optimum condition was 96%. Thermodynamic analysis indicated that the removal efficiency was slightly increased with temperature depending on the positive value of Δ𝐻°, thus indicating that the adsorption phenomenon was endothermic. The Langmuir model fitted the study (R2 = 0.998), demonstrating that the adsorption sites were homogenous. The experimental results were best matched with the second-order kinetic model, implying that chemisorption was the primary process during the adsorption process. Compared to previous research and based on the value of qmax (15.60 mg/g), the biomass was suitable for TEC removal.
Polarization is an important property of light, which refers to the direction of electric field oscillations. Polarization modulation plays an essential role for polarization encoding quantum key distribution (QKD). Polarization is used to encode photons in the QKD systems. In this work, visible-range polarizers with optimal dimensions based on resonance grating waveguides have been numerically designed and investigated using the COMSOL Multiphysics Software. Two structures have been designed, namely a singlelayer metasurface grating (SLMG) polarizer and an interlayer metasurface grating (ILMG) polarizer. Both structures have demonstrated high extinction ratios, ~1.8·103 and 8.68·104 , and the bandwidths equal to 45 and 55 nm for th
... Show MoreThe past decades have witnessed a development in the concept of corporate governance and the transformation of a concept that is limited to large companies listed in capital markets in major economies to an issue that concerns all business activities in the public and private sectors in both large and small countries. The aim of this research is to propose a guide to the mechanisms and rules of governance in the municipal institutions that contributes to the activation of the internal control system to reduce the fraud and manipulation of this activity. Institutions. The research was based on the hypothesis that the implementation of the principles and rules of governance in municipal institutions lead to the contribution of the activati
... Show MoreEstablishing sustainable cities and residential neighborhoods requires the development of new planning strategies, as adopting sustainable planning strategies when planning urban land uses for residential neighborhoods is necessary due to the large number of urban land use problems that have emerged during urbanization. The most prominent modern concept concerned with the land was the concept of sustainability, as sustainable planning aspires to link knowledge with sustainability through measures to achieve it. Therefore, sustainable planning works to apply the principles of sustainability in planning.
And in view of the circumstances that our country went through, which negatively affected various sectors and aspects of life, in
... Show MoreIslamic banks are a financial institution that is interested in attracting financial savings from financial entities and directing them towards those with financial deficits, both for consumption purposes or for investment purposes. It provides banking services provided by commercial banks and other services But based on the principles and principles of Islamic law, and because of its recent emergence in Iraq, its ability to attract savings is not like non-Islamic commercial banks, which puts them in the option of using their capital to achieve its objective of banking. The research started from the premise that "Islamic banks in Iraq during the period (2008-2012) rely on their capital to perform their activities more than they rely on d
... Show MoreAbstract. In this paper, a high order extended state observer (HOESO) based a sliding mode control (SMC) is proposed for a flexible joint robot (FJR) system in the presence of time varying external disturbance. A composite controller is integrated the merits of both HOESO and SMC to enhance the tracking performance of FJR system under the time varying and fast lumped disturbance. First, the HOESO estimator is constructed based on only one measured state to precisely estimate unknown system states and lumped disturbance with its high order derivatives in the FJR system. Second, the SMC scheme is designed based on such accurate estimations to govern the nominal FJR system by well compensating the estimation errors in the states and the lumped
... Show MoreIn recent years, the positioning applications of Internet-of-Things (IoT) based systems have grown increasingly popular, and are found to be useful in tracking the daily activities of children, the elderly and vehicle tracking. It can be argued that the data obtained from GPS based systems may contain error, hence taking these factors into account, the proposed method for this study is based on the application of IoT-based positioning and the replacement of using IoT instead of GPS. This cannot, however, be a reason for not using the GPS, and in order to enhance the reliability, a parallel combination of the modern system and traditional methods simultaneously can be applied. Although GPS signals can only be accessed in open spaces, GP
... Show MoreThis study discussed a biased estimator of the Negative Binomial Regression model known as (Liu Estimator), This estimate was used to reduce variance and overcome the problem Multicollinearity between explanatory variables, Some estimates were used such as Ridge Regression and Maximum Likelihood Estimators, This research aims at the theoretical comparisons between the new estimator (Liu Estimator) and the estimators
In recent years, the Global Navigation Satellite Services (GNSS) technology has been frequently employed for monitoring the Earth crust deformation and movement. Such applications necessitate high positional accuracy that can be achieved through processing GPS/GNSS data with scientific software such as BERENSE, GAMIT, and GIPSY-OSIS. Nevertheless, these scientific softwares are sophisticated and have not been published as free open source software. Therefore, this study has been conducted to evaluate an alternative solution, GNSS online processing services, which may obtain this privilege freely. In this study, eight years of GNSS raw data for TEHN station, which located in Iran, have been downloaded from UNAVCO website
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