Spatial prediction of landslide-susceptible zones in El-Qaá area,Egypt, using an integrated approach based on GIS statistical analysis

Bulletin of Engineering Geology and the Environment - The spatial prediction of landslide susceptibility locations is a crucial task to support risk management and development plans in mountainous...     

Numerical and experimental investigation of a thermosiphon solar water heater system thermal performance used in domestic applications

The thermosiphon is a passive heat exchange method, which circulates a fluid within a system without the need for any electrical or mechanical pumps. The thermosiphon is based on natural convection where the thermal expansion occurs when the temperature difference has a corresponding difference in density across the loop. Thermosiphons are used in different applications such as solar energy collection, automotive systems, and electronics. The current study aims to investigate thermosiphon thermal performance used in domestic applications. The thermal performance of a thermosiphon has been studied by many researchers; however, according to the knowledge of the authors, the influence of the amount of the working fluid on the thermal output has not yet been investigated. Therefore, the influence of the amount of working fluid within the riser pipe has been investigated on the thermal performance of the thermosiphon. In the current study, a computational fluid dynamics model is involved. This model has been validated by comparison with experimental findings. The maximum variation between numerical and experimental results is 14.2% and 11.2% for the working fluid at the inlet and outlet of the absorber pipe, respectively. Furthermore, the results show that the amount of working fluid inside the closed thermosiphon has a great influence on the thermal performance of the system. Additionally, it is found that Case-B, when the amount of working fluid is less than by 10% compared to the traditional model, is the best case among all cases under study. Furthermore, a correlation equation to predict water temperature at the exit of the absorber pipe has been established with an accuracy of 95.05%.     

Extraction optimisation,antioxidant activity and inhibition on α-amylase and pancreatic lipase of polyphenols from the seeds of Syzygium cumini

The objectives of this study were to determine the optimal extraction conditions of polyphenols from Syzygium cumini seeds by response surface methodology and investigate their antioxidant activity and inhibition on α-amylase and pancreatic lipase. As results, the optimal extraction conditions in the ultrasonic extraction process which maximised total polyphenols content, minimised the IC₅₀ values of α-amylase and pancreatic lipase were determined as follows: extraction time 60 min, ethanol concentration 63% and solvent/solid ratio 44 mL g⁻¹. The main phenolic compounds in partially purified fraction of Syzygium cumini seeds were catechin, epicatechin, kaempferol, gallic, 5-caffeoylquinic, caffeic and ferulic acids. In addition, the partially purified fraction inhibited 87.66 ± 5.55 and 86.61 ± 3.15% of α-amylase and pancreatic lipase, respectively. The results suggested that Syzygium cumini seeds could be explored as a natural antioxidant and could be used as a source of highly antidiabetic and anti-obesity bioactive compounds.     

Process Optimization,Physical Properties,and Environmental Stability of an α-Tocopherol Nanocapsule Preparation Using Complex Coacervation Method and Full Factorial Design

α-Tocopherol (α-Toc) has valuable biological activity, but its activity is limited when exposed to environmental factors. Nanocapsules can be used to overcome this problem. Using nanocapsules in the range of 100–200 nm is more beneficial. A 2⁴ full factorial design was carried out to optimize the size of nanocapsules using the complex coacervation method. The four factors were the amount of the wall material, the ratio of core material to wall material, the pH of the solution, and the speed of the homogenizer. The smallest nanocapsules (176 nm) were obtained at a wall content (gelatine and pectin) of 0.8 mg, a percentage of core material (α-Toc) to wall material of 20%, a pH = 4.5, and a homogenizer speed of 12,000 rpm. The encapsulation efficiency was 90.6 ± 1.1%, and the encapsulation yield was 83.4 ± 1.6%. Assessment of the stability of α-Toc after 1 month showed that encapsulation could improve its stability in the presence of three influential factors: humidity, light, and temperature.     

Preparation, Characterization and Photocatalytic Properties of Ba-Cd-Sr-Ti Doped Fe3O4 Nanohollow Spheres on Removal of Congo Red Under Visible-Light Irradiation

In this study, Ba-Cd-Sr-Ti doped Fe₃O₄ nanohollow spheres were successfully prepared via a simple solvothermal method. The crystal size, structure, morphology and elemental analysis of the as-prepared sample were investigated in detail by X-ray diffraction (XRD), FT-IR, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy, respectively. Magnetic hysteresis measurement was carried out on a vibrant sample magnetometer (VSM) showing the soft ferromagnetic property at room temperature. The synthesized nanohollow spheres were employed as a photocatalyst to study the photocatalytic degradation of dye contaminations. The UV-Vis results showed that the specimen could well catalyze the decolorizing of congo red (CR) solution and a removal efficiency of 99.5 % was obtained at pH 6. The optical characteristic of the products was studied by estimating the band-gap energy based on diffuse-reflectance spectroscopy (DRS) which represented the doped magnetite with semiconductor metals to be more prone in the visible region as compared to UV region. Some factors such as initial dye concentration, pH, and contact time influencing the decomposition of CR were evaluated.     

Characterization of mechanically sheared edges of dual phase steels

In recent years advanced high strength steels (AHSS) received increased interest for light structures with improved performance, but they are often sensitive to edge cracking during sheet metal forming. In this study mechanically sheared edges were characterized for three dual phase steels (DP600, DP780 and DP980), sheared with three die clearances (5%t, 10%t, 15%t) and along rolling and transverse directions. Microstructures of the materials were provided first, and then the sheared edges were examined by optical microscopy and scanning electron microscopy that reveal the morphology and random feature of the sheared edges. A factorial analysis was performed to reveal the general trends of the processing parameters on four edge zones. A new strain measurement method was used for characterizing strain distribution in the sheared region, which shows the peak strain to be higher than 3. The strain quickly decreases from sheared edge to interior, leaving a shear-affected zone of about 500 μm or 31% of the thickness. The fracture processes and involved mechanisms were discussed.     

Nicotinic Acid Increases Adiponectin Secretion from Differentiated Bovine Preadipocytes through G-Protein Coupled Receptor Signaling

The transition period in dairy cows (3 weeks prepartum until 3 weeks postpartum) is associated with substantial mobilization of energy stores, which is often associated with metabolic diseases. Nicotinic acid (NA) is an antilipolytic and lipid-lowering compound used to treat dyslipidaemia in humans, and it also reduces non-esterified fatty acids in cattle. In mice the G-protein coupled receptor 109A (GPR109A) ligand NA positively affects the secretion of adiponectin, an important modulator of glucose and fat metabolism. In cattle, the corresponding data linking NA to adiponectin are missing. Our objective was to examine the effects of NA on adiponectin and AMPK protein abundance and the expression of mRNAs of related genes such as chemerin, an adipokine that enhances adiponectin secretion in vitro. Differentiated bovine adipocytes were incubated with pertussis toxin (PTX) to verify the involvement of GPR signaling, and treated with 10 or 15 µM NA for 12 or 24 h. NA increased adiponectin concentrations (p ≤ 0.001) and the mRNA abundances of GPR109A (p ≤ 0.05) and chemerin (p ≤ 0.01). Pre-incubation with PTX reduced the adiponectin response to NA (p ≤ 0.001). The NA-stimulated secretion of adiponectin and the mRNA expression of chemerin in the bovine adipocytes were suggestive of GPR signaling-dependent improved insulin sensitivity and/or adipocyte metabolism in dairy cows.