In this work, the possibility of methylene blue electrochemical reduction, assisted by a hybrid material, based on polynaphthoquinones, doped by Ti/TiO2/VO(OH) composite, has been evaluated from the theoretical point of view. Two mathematical models, one referent to the electrode preparation and another, referent to its action with methylene blue, have been described and analyzed. It was shown that in both of the processes the steady-state stability may be easily obtained and maintained. On the other hand, the oscillatory behavior in this system is possible, being caused by the DEL capacitance influences of both chemical and electrochemical stages.

The electrosynthesis synthesis of squaraine-dye doped conducting polymer for electroanalytical, electrocatalytical and enery conversion purposes has been described theoretically. The correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis. It has been shown that the steady-state mode is easy to obtain and maintain in this process. Depending on the conditions, the synthesis may be diffusion- or kinetically controlled. On the other hand, the oscillatory behavior in this case will be probable due to DEL influences of either electropolymerization process or polymer doping.

The mathematical model for the polythiophene paradox for the polymerization of electrochemically synthetized monomers has been modified, in order to allow the description of an alternative polymer oxidation scenario. The analysis of the model, realized by means of the linear stability theory and bifurcation analysis, has confirmed that in the presence of two parallel oxidation reactions of the polymer, the oscillatory and monotonic instability will be more probable than in the simplest polythiophene paradox systems. The polymer morphology and themical properties will be affected. Nevertheless, the polythiophene, overoxidized in these conditions, may be efficiently deposed and used for electroanalytical and corrosion-protecting purposes.

The corrosion performance of carbon steel in acidic medium with different concentration of synthesized organic compounds namely: 2-Phenylpyrimido[1,2-a] benzimidazol-4(1H)-one (PPBI), was investigated by Potentiodynamic Polarization Curves (PPC) and Electrochemical Impedance Spectroscopy (EIS)  measurements. The obtained results reveal that (PPBI) performs excellently as good corrosion inhibitor for carbon steel in 1.0 M HCl. Polarization curves studies indicated that (PPBI) behaves as mixed-type inhibitor. The calculated inhibition efficiencies from two experiments measurements show the same evolution. Also,  the  inhibition  efficiency  was  found  to increase  with increase of the inhibitor concentrations to reach 86 % at 10-3 M of (PPBI) due to the adsorption of the inhibitor molecule on  the  electrode  surface. Impedance measurements spectra exhibit one capacitive and valid the inhibitive ability confirming that this inhibitor inhibits the corrosion in 1 M HCl through adsorption process following Langmuir adsorption isotherm.

This study focuses on the use of a new synthesized compound namely 2-(4-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)phenoxy)acetic acid (PYR-3) as an efficient sustainable inhibitor for the corrosion of mild steel in 1 M HCl solution.For this purpose, the current assessment was conducted using a range of experimental and theoretical techniques such as weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic‎polarization (PDP), DFT computations and molecular dynamic (MD) simulations.The experimental results revealed that the studied compound give a maximum inhibition efficiency of 87 % and the inhibition ability increased with raising of the inhibitor concentrations. Further, this inhibitor effectively reduced the corrosion rate of MS which is afforded by the adsorption of this compound onto the MS surface obeyed the Langmuir adsorption isotherm via physico-chemical adsorption. The adsorption parameters such as adsorption equilibrium constant (Kads) and free energy of adsorption (ΔG0ads) were calculated and discussed. To provide further insight into theinteraction’s mechanism between our synthesized compound with the iron surface in an acidic medium, computational calculations such as DFT and MD simulations could beof interesting. Overall, the obtained results from theoretical point of view correlate well with the electrochemical parameters.

The results presented in this paper concerned a comparative and performance analysis of three PV technologies Monocrystalline (2kWp), Polycrystalline (1.82kWp) and Amorphous (1.55kWp). These technologies are linked together and formed a grid connected station of total capacity 5.365kWp that is located on the roof of the High School of Technology-Laâyoune-Morocco. The analyses of this installation was made by determining the performance, productivity, performance ratios and yields of three PV technologies for one year, from March 2018 to February 2019. Parameters like annual specific yield, annual capacity and performance ratio were evaluated and found to be 1876.37kWh/kWp/year, 21.42%, and 81.83%, for Polycrystalline, 1405.51kWh/kWp/year, 16.12% and 57.92% for Monocrystalline and 1865.81kWh/kWp/year, 21.31% and 80.03% for Amorphous

A waste to energy approach in pollution controls is highly desirable to create a green and sustainable environment. Microbial Fuel Cell (MFC), which converts organic to electricity via the help of microorganism is one of the examplatory approach of waste to energy concept. Here we tried to find out the influence of MFC technology to the degradation of Total Petroleum Hydrocarbon (TPH) on contaminated sediment. The research used completely randomized design with three treatments and three replications which were control, single-chamber MFC and dual-chamber MFC observed for twenty days. The result showed that the TPH content degraded around 10.26%, 46.15 and 25.64% for control, single-chamber MFC and dual-chamber MFC treatments, respectively. The electricity production for single-chamber treatments was 184.36 mV, 179.59 mA/m2 and 50.57 W/m2 and for dual-chamber MFC was 57.58 mV, 62.51 mA/m2 and 5.76 W/m2. According to annova analysis at 5% significance rate, it could be concluded that the use of MFC technology had shown a significant effect to TPH degradation on contaminated sediment.

In this work, the electroanalytical action VO(OH) – poly(naphthoquinones) in the determination of peroxycompounds has been theoretically analyzed. The redox pair V(III) – V(V) is involved in this case. The analysis of the correspondent bivariant mathematical model confirms the efficiency of the VO(OH) – Poly(naphthoquinone) composite in the peroxide compounds determination. The linear dependence between current and concentration is observed in the wide range of parameter values. On the other hand, the oscillatory behavior is only possible due to the DEL influences of the electrochemical stage.

In Ethiopia there was weak adaptability of a natural existing recyclable earth material of mud block housing due to a lack of skill, technology, and weak physical property such as compressive strength, water absorption, and expansion in the moisture of mud blocks. To solve the problems of housing shortage, deforestation, environmental factors, unsustainable housing, and expensive housing construction mud block is a special strategy in developing countries.  In Identifying of the existing mud block housing typologies and investigate the durability for adaptation in a countrywide, the case study approaches by using physical surveys, interviews, and laboratory analyses were done on raw material, climatic conditions, material quality, and construction techniques. Local material and labor, low cost, climate-friendly, energy efficiency, comfortable in hot areas, and ease of construction was the basic thing for adapting of the mud block houses in countrywide. Surveying the existing mud block houses, developing people’s awareness and advancing the construction technique helps to promote the housing problems, and environmental friendly of mud block house as alternative walling material by replacing trees and energy inefficient material for low-income in the hot areas of Ethiopia.

The presence of heavy metals in the aquatic environment has been a big deal to scientists due to their increased discharge, toxic nature, and other adverse effects on receiving waters. Even a very low concentration of lead in water is very toxic to aquatic life. Lead poisoning in human cause’s severe damage to the kidney, nervous system, reproductive system, liver, and brain causes sickness or death. The main sources of lead in water are the effluents of processing industries. The present research was aimed at modelling the use of sediment as an adsorbent for the removal of Pb2+ ions by adsorption to obtain equilibrium, kinetics and thermodynamic parameters. The experimental results show that the equilibrium contact time was obtained within 60 minutes and the maximum adsorption capacity was found at 2g sediment and 1M Pb(NO3)2 system. The dynamic data fitted the pseudo-second-order kinetic model well. The Linear isotherm model agrees well with the equilibrium experimental data. The thermodynamic parameters were also deduced for the adsorption of Pb2+ ions onto sediment and the results show that the adsorption was spontaneous and exothermic, while the mechanism was proposed to obey physical adsorption (physisorption).