Rigorous peer-review is the corner-stone of high-quality academic publishing [...]

The possibility of estradiol electrochemical determination on an anode, modified by a new triazolic Schiff base, has been theoretically evaluated. The correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis. It was shown that the Schiff base provides an efficient estradiol electrochemical determination in neutral and basic media. The proper basicity of Schiff base and triazolic ring favors the process. The steady-state stability is easy to establish. The oscillatory behavior, in this case, is possible, due to the double electric layer influences of the electrochemical stage.

An electrochemical method for mycotoxin gyromitrin determination, based on an anode, modified by vanadium(III)oxyhydroxyde composite with a novel Schiff base, has been theoretically described. The electrochemical reduction is realized gradually with the formation of vanadium (IV) oxide as a VO(OH) oxidation product. It has been shown that, despite of the hybridity of the reduction mechanism, the electroanalytical process is realized efficiently. The steady-state stability is easy to obtain and maintain. Yet the oscillatory behavior is caused by a unique factor of double electric layer rearrangements, caused by the electrochemical stage.

The present paper focus on problem convective heat transfer of Al2O3-[C4mim][NTf2] ionanofluid in three dimensional differentially heated cavity. The finite volume using SIMPLEC algorithm discretizes the governing equations. The left and the right vertical sidewalls of the considered cube are maintained at constant temperatures Tc and Th, respectively. The remaining walls of the cube are insulated. Effective thermal conductivity and viscosity of the ionanofluid are determined using Brinkman and Maxwell models, respectively. Through a parametric study, the effects of volume fraction  and the Rayleigh number  were analyzed. The results indicate that the Nusselt number of the plane with y equal to half of the cavity, in general, increase with increasing the volume fraction of the nanoparticle.

The current study took place in Souss region and aimed to evaluate the reliability of forecasted weather data provided yobeen forecast software through the identification of relationships between real and forecasted climatic parameter. Real twelve weather station data history were used. Studied climatic parameters are air temperature and humidity, global radiation, wind speed and referential evapotranspiration (ETo). That later depends on previous parameters and was calculated using Panman-Monteith formula.Each of those measured parameters was compared, correlated to its forecasted homologous one. It was, hence, concluded that yobeen forecast, software using GFS forecasting, is able to predict successfully air temperature, global radiation and referential evapotranspiration while it remains less efficient to provide reliable wind speed and air relative humidity unless a calibration effort would be performed.

The objective of this work is to optimize the production of a low-cost activated carbon from Delonix regia (flamboyant) pods through chemical activation with ethanoic acid and carbonization (pyrolysis) process. The effect of production process variables; carbonization temperature, carbonization time and impregnation ratio on the activated carbon yield and surface area (using methylene blue number (MBN) and iodine value number (IVN) as indices) were evaluated using the D-Optimal design of experiment of response surface methodology (RSM). The influence of the production process variables on the Delonix regia pod-derived activated carbon (DRP-AC) was analysed using the analysis of variance (ANOVA) to identify the significant variables. The variations in yield, MBN and IVN of DRP-AC with respect to temperature, time and impregnation ratio were very significant. The quadratic regression models were found to be significant (p < 0.05) and well suitable and satisfactory ( > 0.95) in predicting the yield, MBN and IVN in relation to the production process variables. DRP-AC with maximum or optimum yield of 20.24%, optimum MBN of 71.89 mg/g and IVN of 80.45 mg/g was obtained using optimum production process conditions of: 500 oC (carbonization temperature), 60 min (carbonization time), and 3.78:1 (impregnation ratio). These experimental values were in good agreement with the values predicted by the model with relatively small percentage error (0.33). Fourier-infrared spectroscopy (FTIR) analysis of the surface of the DRP-ACs revealed the presence of adequate functional groups. Therefore, Delonix regia pods are good precursor for activated carbons production.

Metals play predominant prefaces regarding most of industrial components such as the crude oil refining industry although corrosion   performed some banes. The formations of ferrous oxides, sulfides, hydroxides or certain chemical compound is the general definition regarding the corrosion. The rate of corrosion of a metal is regulated by the conditions of surrounding matter and chemical composition of such metal as well. In the current research it was expected to investigate to compare the effect of corrosive properties of two different crude oils on the rates of corrosion in seven different types of ferrous metals and their hardness. The contents of sulfur, mercaptans, organic acids and salt in both crude oils were determined by in order to XRF analyzer, titration methods and salt analyzer and also the chemical compositions of ferrous metals were determined by XRF detector. A batch of similar sized metal coupons was prepared and immersed in both crude oils separately. The corrosion rate of each metal coupon was determined by the weight loss method in order to after 15, 30 and 45 days from the immersion also the corroded surfaces were observed by the optical microscope. The concentrations of copper and ferrous in each crude oil sample were tested by atomic absorption spectroscopy (AAS) and the both initial and final hardness of each metal coupon were tested by Vicker’s hardness tester. According to the results there were observed lower corrosion rates from stainless steels while finding higher corrosion rates in other metals also significant ferrous concentrations in crude oil samples regarding carbon steels, higher corrosion rates of four types of metals in Murban crude although it was less strong regarding corrosive properties than Das Blend, formation corrosion compounds, corrosion cracks, pitting corrosion on metal surfaces and there were observed a slight reduction of  hardness in each metal coupon eventually.

Molecular Modelling Approach has been used for the prediction of anticorrosion properties of 1, 2, 4-triazole derivatives on Steel in Acidic Medium by the quantum Chemical calculation and molecular dynamics (MD) simulation method. Quantum chemical parameters such as the highest occupied molecular orbital (E-HOMO), the energy of the lowest unoccupied molecular orbital (E-LUMO), energy band gap (ΔE), Dipole Moment ,global electronic chemical potential (μ), chemical softness (σ), chemical hardness (η) and  electrophilicity (

The theoretical description for amavadin electrochemical determination by poly(vedelolactone) doping has been given. The analysis of the correspondent mathematical model shows that amavadin may be electrochemically detected by efficient manner, using not only the polymer doping, but also the ion oxidation. The steady-state is easy to maintain stable, and the linearity of the dependence between the concentration and electrochemical parameter is formed easily. On the other hand, the oscillatory behavior in this case is more probable than in the common poly(vedelolactone) doping, due to the presence of additional anion electrooxidation in matrix.

The production of renewable energy depends on weather conditions. In the case of a photovoltaic generator the partial shading considerably reduces its output power capacity and can even cause the destruction of part or all of a panel. Once shaded, a cell is operating in reverse bias and it acts as a charge and dissipates energy, then the cell can be irreversibly damaged, we usually called these hot spot phenomena. In order to avoid this possible phenomenon, manufacturers have resorted to the use of bypass diodes and anti-return diodes. In this paper, we present a simulation of the shading effect of a photovoltaic generator composed of panels mounted in series and in parallel. We will compare the characteristics of power voltage (P-V) for different irradiances in the presence and absence of bypass diode. For the simulation, we will use the single diode model. The simulation is performed under PSIM software.