The effects of using aqueous nanofluids containing covalently functionalized graphene nanoplatelets with triethanolamine (TEA-GNPs) as novel working fluids on the thermal performance of a flat-plate solar collector (FPSC) have been investigated. Water-based nanofluids with weight concentrations of 0.025%, 0.05%, 0.075%, and 0.1% of TEA-GNPs with specific surface areas of 300, 500, and 750 m2/g were prepared. An experimental setup was designed and built and a simulation program using MATLAB was developed. Experimental tests were performed using inlet fluid temperatures of 30, 40, and 50 °C; flow rates of 0.6, 1.0, and 1.4 kg/min; and heat flux intensities of 600, 800, and 1000 W/m2. The FPSC’s efficiency increased as the flow rate and heat flux intensity increased, and decreased as inlet fluid temperature increased. When using nanofluids in the FPSC, the measured temperatures of absorber plate and tube wall decreased down to 3.35% and 3.51%, respectively, with the increase in weight concentration and specific surface area, while the efficiency increased up to 10.53% for 0.1- wt% TEA-GNPs nanofluid with specific surface area of 750 m2/g, in comparison with water. When using water as heat transfer fluid, very good agreement was obtained between the experimental and predicted values of absorber plate temperature, tube wall temperature, and collector’s efficiency with maximum differences of 3.02%, 3.19%, and 3.26%, respectively. While, when using nanofluids, higher differences were found, up to 4.74%, 4.7%, and 13.47% for TEA-GNPs nanofluid with specific surface area of 750 m2/g, respectively. Accordingly, the MATLAB code was capable of simulating the thermal performance of FPSCs utilizing nanofluids as their heat transfer fluids with acceptable accuracy. Values of performance index were all greater than 1, and increased as weight concentration increased up to 1.104 for 0.1- wt% TEA-GNPs nanofluid with specific surface area of 750 m2/g, implying higher positive effects on efficiency than negative effects on pressure drop. Accordingly, the investigated nanofluids can efficiently be used in FPSCs for enhanced energy efficiency, and the 0.1- wt% water-based TEA-GNPs nanofluid with specific surface area of 750 m2/g was comparatively the superior one.
The electrochemical polymerization of the monomer sulfanilamide (SAM) in an aqueous solution at room temperature produces polysulfanilamide (PSAM). The Fourier Transform Infrared spectroscopy (FTIR) was used to investigate the properties of the prepared polymer layer that generated on the stainless steel (St.S) surface (working electrode) and Atomic Force Microscope (AFM) was used to characterize the morphology, topology, and detailed surface structure of polymer layer that generated on the surface. The corrosion behavior of uncoated and coated St.S were evaluated by using the electrochemical polarization method in a 0.2 M HCl solution and a temperature range of 293–323 K, the anticorrosion action of the polymer coating on stainless steel
... Show MoreIn the last few years, the literature conferred a great interest in studying the feasibility of using memristive devices for computing. Memristive devices are important in structure, dynamics, as well as functionalities of artificial neural networks (ANNs) because of their resemblance to biological learning in synapses and neurons regarding switching characteristics of their resistance. Memristive architecture consists of a number of metastable switches (MSSs). Although the literature covered a variety of memristive applications for general purpose computations, the effect of low or high conductance of each MSS was unclear. This paper focuses on finding a potential criterion to calculate the conductance of each MMS rather t
... Show MoreBACKGROUND Multiple myeloma (MM) is a plasma cell disorder characterized by the infiltration of clonal plasma cells in the bone marrow and the detection of a monoclonal immunoglobulin in serum and/or urine. Renal failure, anemia, hypercalcemia, and the presence of bone lesions are the hallmarks of the disease. The study aimed to evaluate the clinical, hematological, radiological, and immunophenotypic features of MM patients and to identify prognostic factors influencing survival outcomes. This cohort study included 77 newly diagnosed, untreated MM patients. Their clinical presentation, laboratory data, imaging results, and the expression of flow cytometry markers were analyzed in correlation with the 1-year overall survival (OS). The mean a
... Show MoreThis work includes preparation of Az, Qz, and Tz derivatives from the reaction of Schiff base (Sb) derivative with anthranilic acid, chloroacetyl chloride, and sodium azide, as well as, the characterization via FT-IR, 1H-NMR, and 13CNMR. The anticorrosion inhibition of these compounds was studied and the measurements of carbon steel (CS) corrosion in sodium chloride solution 3.5% (blank) and inhibitor in solutions were calculated at a temperature range of 293-323 K by the technique of electrochemical polarization. In addition, some thermodynamic and kinetic activation parameters for inhibitor and blank solutions (Ea⋇, ΔH⋇, ΔS⋇, and ΔG⋇) were determined. The results showed high inhibition efficacy for all the prepared compounds,
... Show MoreFinding a path solution in a dynamic environment represents a challenge for the robotics researchers, furthermore, it is the main issue for autonomous robots and manipulators since nowadays the world is looking forward to this challenge. The collision free path for robot in an environment with moving obstacles such as different objects, humans, animals or other robots is considered as an actual problem that needs to be solved. In addition, the local minima and sharp edges are the most common problems in all path planning algorithms. The main objective of this work is to overcome these problems by demonstrating the robot path planning and obstacle avoidance using D star (D*) algorithm based on Particle Swarm Optimization (PSO)
... Show MoreNew derivatives of Schiff bases were synthesized from the aldehyde derivative (Ma2) which was produced by reacting the mefenamic acid (Ma) with thionyl chloride to obtain the acid halide derivative (Ma1). Compound (Ma1) was dissolved in DMF and mixed with p-hydroxybenzaldehyde which was previously dissolved with pyridine to obtain the aldehyde derivative (Ma2). In the final step, derivatives of Schiff bases were synthesized by reacting the aldehyde (Ma2) with a number of different aromatic primary amines in the presence of glacial acetic acid to obtain the new derivatives Ma [3-10]. The new prepared compounds were characterized by melting points and with spectral data FT-IR, 13C-NMR and 1H-MNR (some of them). The vital effectiven
... Show MoreSource, sedimentation, coagulation, flocculation, filter, and tank are parts of a water treatment plant. As a result, some issues threaten the process and affect the drinking water quality, which is required to provide clean drinking water according to special standards and international and local specifications, determined by laboratory results from physical, chemical, and biological tests. In order to keep the water safe for drinking, it is necessary to analyze the risks and assess the pollution that occurs in every part of the plant. The method is carried out in a common way, which is monitoring through laboratory tests, and it is among the standards of the global and local health regulators