A detailed experimental study was devoted to the anodic oxidation of oxalic acid using manganese dioxide rotating cylinder anode with the objective to evaluate in a systematic way the effect on the oxalic acid oxidation process of several relevant parameters, including the presence of sodium chloride, the current density (J), the rotation speed, the temperature, and the initial concentration of oxalic acid. Thin manganese dioxide film on graphite substrate has been prepared by electrochemical oxidation from MnSO4-H2SO4 electrolyte. The morphology of this electrode was investigated by XRD, SEM, EDS and AFM techniques. The results show that a firm γ-structure of MnO2 film on graphite rod can be obtained successfully. The results indicate that the presence of NaCl has a vital role on the performance of the oxalic acid incineration process. Also current density has the major effect on the removal and current efficiencies. Positive effect of temperature on the removal and current efficiencies and negative effect of rotation speed were observed. The best adopted operative conditions were T = 50°C, J = 40 mA/cm2 and 200 rpm in the presence of 1g/l NaCl where a conversion of about 97% and a current efficiency close to 55% with energy consumption less than 28 kWh(kg of COD)−1 were obtained after four hours of electrolysis time. The findings of the present research validate that incineration of oxalic acid can be carried out successfully on MnO2 anode.
One of the most important problems in the statistical inference is estimating parameters and Reliability parameter and also interval estimation , and testing hypothesis . estimating two parameters of exponential distribution and also reliability parameter in a stress-strength model.
This parameter deals with estimating the scale parameter and the Location parameter µ , of two exponential distribution ,using moments estimator and maximum likelihood estimator , also we estimate the parameter R=pr(x>y), where x,y are two- parameter independent exponential random variables .
Statistical properties of this distribution and its properti
... Show MoreThe present study aimed to examine the effect of endosulfan insecticide on some molecular and biochemical parameters in white mice. Thirty mice were separated randomly into three groups for treatment with endosulfan. One group (G1) served as the control, while the other two groups received intraperitoneal injections of endosulfan G2 (3 mg/kg) and G3 (17 mg/kg) twice a week for 21 and 45 days, respectively. A biochemical study by measuring liver function parameters, including (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)) and kidney function parameters, including (Blood Urea and Creatinine) and malondialdehyde (MDA), catalase activity (CAT). This study also tested DNA damage by comet assay (normal%, low%, med
... Show MoreElectrochemical oxidation in the presence of sodium chloride used for removal of phenol and any other organic by products formed during the electrolysis by using MnO2/graphite electrode. The performance of the electrode was evaluated in terms fraction of phenol and the formed organic by products removed during the electrolysis process. The results showed that the electrochemical oxidation process was very effective in the removal of phenol and the other organics, where the removal percentage of phenol was 97.33%, and the final value of TOC was 6.985 ppm after 4 hours and by using a speed of rotation of the MnO2 electrode equal to 200 rpm.
A seemingly uncorrelated regression (SUR) model is a special case of multivariate models, in which the error terms in these equations are contemporaneously related. The method estimator (GLS) is efficient because it takes into account the covariance structure of errors, but it is also very sensitive to outliers. The robust SUR estimator can dealing outliers. We propose two robust methods for calculating the estimator, which are (S-Estimations, and FastSUR). We find that it significantly improved the quality of SUR model estimates. In addition, the results gave the FastSUR method superiority over the S method in dealing with outliers contained in the data set, as it has lower (MSE and RMSE) and higher (R-Squared and R-Square Adjus
... Show MoreThe study aimed to identify the awareness degree of teacher students in the department of Arabic language and their supervisors at Al-aqsa University for their future roles in the age of knowledge. To achieve this objective, descriptive- analytical approach was used. The instruments of this study were two questionnaires: first one consist of (20) item for teacher students, and the second consist of (27) item for educational supervisors which covered three roles: professional, technological, and humanitarian. The sample was (120) student selected randomly, and (39) supervisors of Arabic language. The result revealed that the mean of degree awareness of teacher students and their supervisors of future role are (3.857), (3.472) respectively
... Show MoreThe cost of microalgae harvesting constitutes a heavy burden on the commercialization of biofuel production. The present study addressed this problem through economic and parametric comparison of electrochemical harvesting using a sacrificial electrode (aluminum) and a nonsacrificial electrode (graphite). The harvesting efficiency, power consumption, and operation cost were collected as objective variables as a function of applied current and initial pH of the solution. The results indicated that high harvesting efficiency obtained by using aluminum anode is achieved in short electrolysis time. That harvesting efficiency can be enhanced by increasing the applied current or the electrolysis time for both electrode materials, where 98
... Show MoreTwo modes of electrochemical harvesting for microalgae were investigated in the current work. A sacrificial anode (aluminum) was used to study the electrocoagulation-flotation process, and a nonsacrificial anode (graphite) was used to investigate the electroflotation process. The study inspected the effect of chloride ions concentration and the interelectrode distance on the performance of the electrochemical harvesting processes. The results demonstrated that both electrodes achieved maximum harvesting efficiency with a 2 g/L NaCl concentration. Interestingly, by increasing the NaCl concentration to 5 g/L, the harvesting efficiency reduced dramatically to its lowest value. Generally, the energy consumption decreased with increasing
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