Study of circular and elliptical tube arrays as cross flow heat exchangers

Maximizing the heat transfer and reducing both the flow resistance and the overall size are vital in heat exchangers design. In view of that, in the present study circular and elliptical tubes were studied as the basic components of heat exchangers. The tubes were arranged to form single in line circular and elliptical tube arrays. The circular tube array consists of 10 tubes with diameter of 22.25 mm, while the elliptical tube array consists of 18 tubes with axis ratio of 0.3. In both arrays, 6.2 mm gab between each two adjacent tubes was kept. The experiments were conducted in a closed loop thermal wind tunnel facility with a 305 mm x 305 mm x 600 mm test section. The study was for heating of air via water in cross flow. For the two arrays, Rea was ranged from 17000 to 49000, and mw was varied from 0.01 to 0.11 kg/s. The study revealed that mainly the Reynolds number controls the heat transfer mechanism at the air side. Correlations in term of Nua and Sta variations with Rea were established. Also, the pressure drop across the arrays was observed and the results were correlated in term of

The effect of banana peels supplemented diet on acute liver failure rats

AbstractPeel of vegetables and fruits are of the most important part that helps in protecting the body from diseases, getting rid of the free radicals, as they contain vitamins and minerals which are antioxidant, in addition to phenols. Previous studies have proved the existence of vitamin C, E, and B6 in banana peels, especially vitamin C that can act as an antioxidant.The present study was performed to examine the effect of fresh and dried banana peels consumption on liver function (albumin, GPT, GOT, LDH, GGT and ALP) and lipid profiles cholesterol, triglycerides, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and very low-density lipoprotein (VLDL) on acute liver failure rats induced by carbon tetrachloride. The chemical constituents, vitamins, minerals and fiber were determined for the tested fresh and dried banana peels.This work was carried out on 40 adult male white albino rats randomly classified into eight groups (each of 5 rats). The first group was fed on basal diet as a “negative control”. The other seven groups were injected by carbon tetrachloride to induce liver failure. The second group fed on basal diet as acute liver failure rat’s untreated “positive control”, the third into five groups fed on basal diet containing 5%, 10% and 15% fresh banana peels while the six into eight groups fed on basal diet containing of 5%, 10% and 15% dried banana peels for a period of four consecutive weeks.Results revealed that all acute liver failure groups administrated with different levels of fresh banana peels (5%, 10% and 15%) had significant decrease in liver function, total cholesterol, triglycerides, LDL-c and VLDL-c cholesterol comparing with the positive control group. On the other hand, significant increase in HDL-c was recorded in all acute liver failure groups administrated with dried banana peels 5% and 10% comparing with control positive group. It was suggested that, consumption of fresh and dried banana peels may modify the risk of acute liver failure patients

On the Geometry of Equiform Normal Curves in the Galilean Space G4

In our article, we establish the definition of the Equiform Normal curves in Galilean space G4. To obtain the position vector of an Equiform Normal curve in G4, we have to solve an integro-differential equation in μ2, where μ2 is the position function of a space curve γ (σ ) in the direction of third vector V3 of the Galilean space. Special cases of Equiform Normal curvatures are discussed. Finally, we prove that there is no equiform normal curve that is congruent to an Equiform Normal curve in G4

Detecting Heart Attacks Using Learning Classifiers

Cardiovascular diseases (CVDs) have emerged as a critical global threat to human life. The diagnosis of these diseases presents a complex challenge, particularly for inexperienced doctors, as their symptoms can be mistaken for signs of aging or similar conditions. Early detection of heart disease can help prevent heart failure, making it crucial to develop effective diagnostic techniques. Machine Learning (ML) techniques have gained popularity among researchers for identifying new patients based on past data. While various forecasting techniques have been applied to different medical datasets, accurate detection of heart attacks in a timely manner remains elusive. This article presents a comprehensive comparative analysis of various ML techniques, including Decision Tree, Support Vector Machines, Random Forest, Extreme Gradient Boosting (XGBoost), Adaptive Boosting, Multilayer Perceptron, Gradient Boosting, K-Nearest Neighbor, and Logistic Regression. These classifiers are implemented and evaluated in Python using data from over 300 patients obtained from the Kaggle cardiovascular repository in CSV format. The classifiers categorize patients into two groups: those with a heart attack and those without. Performance evaluation metrics such as recall, precision, accuracy, and the F1-measure are employed to assess the classifiers’ effectiveness. The results of this study highlight XGBoost classifier as a promising tool in the medical domain for accurate diagnosis, demonstrating the highest predictive accuracy (95.082%) with a calculation time of (0.07995 sec) on the dataset compared to other classifiers

The Effect of Sorbitol and Mannitol Supplementation at Casing on the Productive characteristics of Agaricus bisporus Mushroom

This study is aimed at investigating the effect of supplementing 1, 3 and 5% of Sorbitol and Mannitol at casing on the productive characteristics of the mushroom Agaricus bisporus. The results revealed a significant increase in the total production and biological efficiency of Agaricus bisporus mushroom .Treatment 1% Sorbitol mushroom recorded the highest production (1286, 90 g/bag) compared with 798.5 g/bag for the control group and 745 g/bag for the Mannitol 1% mushroom (p<0.05).Besides, the biological efficiency was increased from 53.23% to 85.79% with the same supplement. None of the Mannitol supplemented treatment surpassed that of the control group for both traits. However Mannitol 1% recorded significantly higher values when compared with other Mannitol treatments for the total yield and biological efficiency .Sorbitol and Mannitol1% treatments showed significantly the higher values for fruiting body number and the lowest fruit body weight (80, 40 and 16.25 and 17.74, numbers and grams, respectively). Most of the yield occurred on the first break. The full growth compost supplemented with 1% Sorbitol tended to have a more synchronous maturation for the second break in fewer days when mushrooms were harvested. Earliness (days from casing ) for Sorbitol, Mannitol 1% treatments and the control group mushroom  was reported  to be 18 days which differ significantly as  compared with all other  treatments(p<0.05). Keywords: Agaricus bisporus, Sorbitol and Mannitol, Casing layer

Protective Effect of Humic acid and Chitosan on Radish (Raphanus sativus, L. var. sativus) Plants Subjected to Cadmium Stress

BackgroundHumic acid or chitosan has been shown to increase plant growth, yield and improving physiological processes in plant, but its roles on alleviating the harmful effect of cadmium on plant growth and some physiological processes in plants is very rare. Pot experiments were conducted to study the role of 100 and 200 mg/kg dry soil from either humic acid or chitosan on counteracted the harmful effects of cadmium levels (100 and 150 mg/kg dry soil) on radish plant growth and some physiological charactersResultsCadmium at 100 and 150 mg kg-1 soil decreased significantly length, fresh and dry weights of shoot and root systems as well as leaf number per plant in both seasons. Chlorophyll, total sugars, nitrogen, phosphorus, potassium, relative water content, water deficit percentage and soluble proteins as well as total amino acids contents were also decreased. Meanwhile, cadmium concentration in plants was increased. On the other hand, application of chitosan or humic acid as soil addition at the concentration of 100 or 200 mg kg-1 increased all the above mentioned parameters and decreased cadmium concentrations in plant tissues. Chitosan at 200 mg kg-1 was the most effective than humic acid at both concentrations in counteracting the harmful effect of cadmium stress on radish plant growth.ConclusionIn conclusion, both natural chelators, in particular, chitosan at 200 mg/kg dry soil can increase the capacity of radish plant to survive under cadmium stress due to chelating the Cd in the soil, and then reduced Cd bio-availability

Recovery of Metal Values from Useless Printed Circuit Boards

This study provides a hydrometallurgical method to recover copper, lead, tin and gold from useless printed circuit boards. Metals in the board were leached with different mineral acids. Gold, if present, was first recovered by filtering from the acid solution, washed and polished. Metal salts went into the acidic leachant were separately recovered, washed and dried. These were thermally reduced using carbon to obtain reduced metals. The polymeric base material was found safe for feasible for reuse in the manufacture of new printed circuit boards. Parameters affecting the recovery factor were studied. Results obtained showed that nitric acid was more effective compared to sulfuric or hydrochloric acid. The extent of metals dissolution increases with increase in acid molarity, stoichiometric ratio, temperature and time of leaching. With sulfuric acid, copper dissolved in > 6 M solution at > 75 °C whereas lead and tin did not. With nitric acid, all metals dissolved on hot conditions whereby tin deposited upon cooling as basic oxide. Lead was separated from copper as chloride. Copper was separated as solid sulfide. The recovered compounds were reduced with hydrogen gas or by carbon at temperatures up to 1000 °C. A separation factor of 98.4-96.2% was achieved