Artificial roughness on the absorber plate of a Solar Air Heater (SAH) is a popular technique for increasing its effective efficiency. The study investigated the effect of geometrical parameters of discrete multi-arc ribs (DMAR) installed below the SAH absorber plate on the effective efficiency. The effects of major roughness factors, such as number of gaps (Ng = 1-4), rib pitch (p/e = 4-16), rib height (e/D = 0.018-0.045), gab width (wg/e = 0.5-2), angle of attack ( = 30-75), and Reynolds number (Re= 2000-20000) on the performance of a SAH are studied. The performance of the SAH is evaluated using a top-down iterative technique. The results show that as Re rises, SAH-effective DMAR's efficiency first ascends to a specified value of Re to attain the maximum values then falls. The useful energy gained via SAH-DMAR is higher by an average of12% when compared to smooth SAH. According to the findings, the effective efficiency of SAH-DMAR is 9.4% higher thanthat of smooth SAH. The maximum thermal efficiency of SAH-DMAR and smooth SAH is 81.1 % and 74.7 %, respectively.
Dental clinicians and professionals need an affordable, nontoxic, and effective disinfectant against infectious microorganisms when dealing with the contaminated dental impressions. This study evaluated the efficiency of hypochlorous acid (HOCl) as an antimicrobial disinfectant by spraying technique for the alginate impression materials, compared with sodium hypochlorite, and its effect on dimensional stability and reproduction of details. HOCl with a concentration of 200 ppm for 5 and 10 min was compared with the control group (no treatment) as a negative control and with sodium hypochlorite (% 0.5) as a positive control. Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa were selected to assess the antimicrobi
... Show MoreDental clinicians and professionals need an affordable, nontoxic, and effective disinfectant against infectious microorganisms when dealing with the contaminated dental impressions. This study evaluated the efficiency of hypochlorous acid (HOCl) as an antimicrobial disinfectant by spraying technique for the alginate impression materials, compared with sodium hypochlorite, and its effect on dimensional stability and reproduction of details. HOCl with a concentration of 200 ppm for 5 and 10 min was compared with the control group (no treatment) as a negative control and with sodium hypochlorite (% 0.5) as a positive control. Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa were selected to assess the antimicrobi
... Show MoreMeasuring the level of communicative competence in news headlines and the level of stylistic and semantic processing in its formulation requires creating a quantitative scale based on the bases on building the scales and their standards. As judging by scientific of journalism studies lies in the possibility of quantifying the journalistic knowledge, i.e. the ability of this knowledge to shift from qualitative language to its equivalent in the language of numbers.
News headlines and editorial processing are one of the journalistic knowledges that should be studied, analyzed stylistically and semantically; their conclusions drawn and expressed in numbers. Press knowledge is divided into two types:<
... Show MoreThis research investigates manganese (Mn) extraction from Electric Arc Furnace Steel Slag (EAFS) by using the Liquid-liquid extraction (LLE) method. The chemical analysis was done on the slag using X-ray fluorescence, X-ray diffraction, and atomic absorption spectroscopy. This work consisted of two parts: the first was an extensive study of the effect of variables that can affect the leaching process rate for Mn element from slag (reaction time, nitric acid concentration, solid to liquid ratio, and stirring speed), and the second part evaluates the extraction of Mn element from leached solution. The results showed the possibility of leaching 83.5 % of Mn element from the slag at a temperature of 25°C, nitric acid co
... Show MoreThe issue of measurement of operational efficiency and productivity plays a major role in determining the weakness of the company, especially in relation to the productive processes, and thus starting to address these points and improve their performance. Hence the problem of research on how to determine the constraints in the production process, to identify weaknesses in the company. The research aims to clarify the role of throughput accounting in measuring the operational efficiency of the company in addition to clarify some of the constraints and causes behind them. The study concluded a set of conclusions, the most important of which is the availability of throughput accounting indicators that help in measuring operational efficienc
... Show MoreSoil fertility is a crucial factor in measuring soil quality, it indicates the extent to which soil can support plant life. Soil fertility is measured by the amount of macro and micronutrients, pH, etc. Soil nutrients are depleted after each harvest and therefore must be added. To maintain soil nutrient levels, fertilizer is added to the soil. Adding fertilizer in the precise amount is a matter of great importance because excess or insufficient application can harm plant life and reduce productivity. The use of modern technology is a solution to this problem. Although automated techniques for sowing, weeding, crop harvesting, etc. have been proposed and implemented, none of the techniques are aimed to maintaining soil fertility. The study a
... Show MoreThis work studies the impact of input machining parameters of Electrical Discharge Machining (EDM) on the machining process performance. Tool steel O1 was selected as the workpiece material, copper as the electrode material, and kerosene as the dielectric medium. Experimental runs have been carried out with a Design of Experiment (DOE) technique. Twenty tests are accomplished with the current range of (18 to 24 Ampere), a pulse duration range of (150 to 200 µs), and a pulse-off time range of (25 to 75 µs). Based upon the experimental study's output results, the EDM parameter's effect (voltage of power supply, discharge current, pulse duration, and pulse pause interval) on the responses of the process represented by sur
... Show MoreOil/water emulsions are one of the major threats to environment nowadays, occurs at many stages in the production and treatment of crude oil. The oil recovery process adopted will depend on how the oil is present in the water stream. Oil can be found as free oil, as an unstable oil/water emulsion and also as a highly stable oil/water emulsion. The current study was dedicated to the application of microbubble air flotation process for the removal of such oily emulsions for its characters of cost-effective, simple structure, high efficiency and no secondary pollution. The influence of several key parameters on the process removal efficiency was examined, namely, initial oil concentration, pH value of t
Continuous turbidimetric analysis (CTA) for a distinctive analytical application by employing a homemade analyser (NAG Dual & Solo 0-180°) which contained two consecutive detection zones (measuring cells 1 & 2) is described. The analyser works based on light-emitting diodes as a light source and a set of solar cells as a light detector for turbidity measurements without needing further fibres or lenses. Formation of a turbid precipitated product with yellow colour due to the reaction between the warfarin and the precipitation reagent (Potassium dichromate) is what the developed method is based on. The CTA method was applied to determine the warfarin in pure form and pharmaceu