Maximization of heat transfer density rate from a single row of rhombic tubes cooled by forced convection based on constructal design

The heat transfer density rate from a row of rhombic tubes cooled by forced convection is maximized based on constructal design. A row of parallel rhombic tubes are placed in a fixed volume, the horizontal axis of the tubes is kept constant while the vertical axis of the tubes and the spacing between the tubes are changed to facilitate the heat flow from the tubes to the coolant. The tubes are kept at constant temperature and the incoming free‐stream flow is induced by constant pressure drop. For steady, two‐dimensional, incompressible, and laminar forced convection, the governing equations are solved numerically by finite volume method with SIMPLE algorithm. The dimensionless pressure drop (Bejan number, Be) ranging from 10 ³ to 10 ⁵, the range of the vertical axis of the tube is 0.2 ≤ B ≤ 2, and the working fluid is air ( Pr = 0.71). The results show that the optimal spacing decreases and the maximum heat transfer density increases as the Bejan number increases for all vertical axes of the tube. Bejan number and the bluntness of the tube have a significant effect of the flow structure (separation and vortex formation) around the tubes at the optimal spacings.     

Rheological,Thermodynamic, and Gas Solubility Properties of Phenylacetic Acid‐Based Deep Eutectic Solvents

Choline chloride + phenylacetic acid‐based deep eutectic solvents are studied. Their most relevant experimental physicochemical properties at different mixing ratios together with the CO₂ solubility data obtained in wide pressure and temperature ranges are reported. The presented materials exhibit a significant CO₂ capture performance with low corrosion effect when compared with the most common amine‐based CO₂ capture agents. Detailed rheological measurements are carried out and various models are applied to describe the dynamic flow behavior of the solvents. The CO₂ absorption mechanism is evaluated by studying the behavior of the liquid gas and interface. Due to the advantages of low cost, nontoxicity, and favorable physical properties, these solvents are an environmentally promising alternative for effective CO₂ capture technological applications.     

Spectral efficiency (SE) enhancement of NOMA system through iterative power assignment

Wireless Networks - This paper studies enhancing non-orthogonal multiple access (NOMA) spectral efficiency (SE) through optimizing the assigned power to each NOMA user depending on their channel...     

An extract of <i>Hypericum perforatum</i> induces wound healing through inhibitions of Ca²⁺ mobilizations,mitochondrial oxidative stress and cell death in epithelial cells: Involvement of TRPM2 channels

The wound is induced by several mechanical and metabolic factors. In the etiology of the wound recovery, excessive oxidative stress, calcium ion (Ca²⁺) influx, and apoptosis have important roles. Ca²⁺-permeable TRPM2 channel is activated by oxidative stress. Protective roles of Hypericum perforatum extract (HP) on the mechanical nerve injury-induced apoptosis and oxidative toxicity through regulation of TRPM2 in the experimental animals were recently reported. The potential protective roles in HP treatment were evaluated on the TRPM2-mediated cellular oxidative toxicity in the renal epithelium (MPK) cells. The cells were divided into three groups as control, wound, and wound + HP treatment (75 µM for 72 h). Wound diameters were more importantly decreased in the wound+HP group than in the wound group. In addition, the results of laser confocal microscopy analyses indicated protective roles of HP and TRPM2 antagonists (N-(p-Amylcinnamoyl) anthranilic acid and 2-aminoethyl diphenylborinate) against the wound-induced increase of Ca²⁺ influx and mitochondrial ROS production. The wound-induced increase of early (annexin V-FITC) apoptosis and late (propidium iodide) apoptosis were also decreased in the cells by the HP treatment. In conclusion, HP treatment acted protective effects against wound-mediated oxidative cell toxicity and apoptosis through TRPM2 inhibition. These effects may be attributed to their potent antioxidant effect.     

The Water-Soluble Peripheral Substituted Phthalocyanines as Corrosion Inhibitors for Copper in 0.1 N HCl: Gravimetric,Electrochemical, SEM-EDS,and Quantum Chemical Calculations

Protection of Metals and Physical Chemistry of Surfaces - Corrosion inhibition effects of water-soluble peripheral substituted cobalt, copper and zinc metallophthalocyanines (CoPc (1), CuPc (2) and...     

Atmospheric and anthropogenic deterioration of the İvriz rock monument: Ereğli-Konya,Central Anatolia,Turkey

Bulletin of Engineering Geology and the Environment - The aim of this study is to determine the extent of deterioration of the limestone on which the İvriz rock monument is engraved. This...