The efficiency of solar energy absorption in solar heaters is increased by the use of selective absorption coating that possesses high absorption of solar radiation in the UV-visible spectrum as well as low emission at the operating temperature in the infrared region. In this work, novel selective coatings were synthesized by improving the selectivity of chromium oxide (Cr₂O₃) nanoparticles by doping with carbon nanoparticles using the exploding wire technique for carbon rods by high current in suspended Cr₂O₃ particles. The structural properties and surface topography were studied by XRD and FE-SEM, which illustrate the carbon-coated Cr₂O₃ nanoparticles. The prepar

Dam break is series phenomenon that can result in fatal consequences and loss of properties. Unfortunately, the observed consequences can only be available after the dam breaks. Therefore, it is important to anticipate what will happen prior to dam break to issue suitable warning and locate the possible risk areas. This study attempts to simulate the case of dam break in Blue Nile at Roseires dam and see its consequences downstream. Roseires dam lies at a distance of 630 km south of Khartoum, Sennar dam lies at about 260 km downstream of Roseires dam. In this study hydraulic model is developed based of Hydraulic Engineering Centre (HEC), River Analysis System (RAS), and HEC- RAS. The HEC-RAS based model is calibrated and validated usi

      A model using the artificial neural networks and genetic algorithm technique is developed for obtaining optimum dimensions of the foundation length and protections of small hydraulic structures. The procedure involves optimizing an objective function comprising a weighted summation of the state variables. The decision variables considered in the optimization are the upstream and downstream cutoffs lengths and their angles of inclination, the foundation length, and the length of the downstream soil protection. These were obtained for a given maximum difference in head, depth of impervious layer and degree of anisotropy. The optimization carried out is subjected to constraints that ensure a safe structure aga

Microencapsulated of paraffin wax which acts as core material of phase change
material covered by polymer was prepared by using rabid (physical-chemical) with lower
energy (green) method. Prepolymer of condensed Melamine-Formaldehyde resin, was
solidified by heat effect gradually and surrounds the Paraffin wax as microcapsules. The
diameter of the prepared capsules was about (170-220) micron which has a proportion with
the prepolymer temperature, otherwise the thermal analysis appears as a best value of
enthalpy (ΔH) which was (12 J/gm) when the prepolymer temperature was (60˚C)

An indirectly method is used to determine hydrogen peroxide. The method based on oxidation of chromium (III) ion by hydrogen peroxide in basic medium to form chromate ion which react with barium (II) ion to produce a yellow precipitate (BaCrO4). Under the optimum established conditions, the linear range of 0.50-25.00 mmol L-1 along with correlation coefficient (r) of 0.9992, Limit of detection (LOD) 0.68 μg / 100 μL, precision expressed as relative standard deviation for six replication measurements at 5.0 mmol.L-1 H2O2 of less than 2% were obtained for hydrogen peroxide. The developed method was successfully applied for the estimation of H2O2 in three pharmaceuticals preparation of different companies using continuous flow injection o

The aim of the research is to use this technique and to determine the effect of this method in reduce cost per unit of the company. The traditional method used in the company the research sample to determine the indirect costs, the definition of the concepts and characteristics of the method of cost-based activity and the cost method based on time-driven activity and justifications applied to companies.   In order to achieve the research objectives, the main hypotheses were formulated. That was represented: (The applied of (TDABC) Time driven activity based costing method in reducing indirect costs, leads reduce cost per unit than the use of the traditional method of allocating indirect costs in the research sample company).&nb

         Over the last few decades, many instructors have been trying all kinds of teaching methods, but without benefit. Nevertheless, in the 1986, a new technique is appeared which called K-W-L technique, it  is specified for reading comprehension passages because reading  skill is not easy matter for students for specific purposes (ESP).therefore, the K-W-L technique is a good one for thinking and experiences. To fulfill the aims and verify the hypothesis which reads as follows" it is hypothesized that there are no significant differences between the achievements of students who are taught according to K-W-L technique and those who are taught according to the traditional method

In recent years, Bitcoin has become the most widely used blockchain platform in business and finance. The goal of this work is to find a viable prediction model that incorporates and perhaps improves on a combination of available models. Among the techniques utilized in this paper are exponential smoothing, ARIMA, artificial neural networks (ANNs) models, and prediction combination models. The study's most obvious discovery is that artificial intelligence models improve the results of compound prediction models. The second key discovery was that a strong combination forecasting model that responds to the multiple fluctuations that occur in the bitcoin time series and Error improvement should be used. Based on the results, the prediction acc