University of Gabès

About: University of Gabès is a education organization based out in Gabès, Tunisia. It is known for research contribution in the topics: Adsorption & Dielectric. The organization has 1772 authors who have published 2903 publications receiving 28420 citations. The organization is also known as: University of Gabes & UG.

On the causal dynamics between economic growth, renewable energy consumption, CO2 emissions and trade openness: Fresh evidence from BRICS countries

Abstract: The current study investigates the causal relationship between economic growth and renewable energy consumption in the BRICS countries over the period 1971–2010 within a multivariate framework. The ARDL bounds testing approach to cointegration and vector error correction model (VECM) are used to examine the long-run and causal relationships between economic growth, renewable energy consumption, trade openness and carbon dioxide emissions. Empirical evidence shows that, based on the ARDL estimates, there exist long-run equilibrium relationships among the competing variables. Regarding the VECM results, bi-directional Granger causality exists between economic growth and renewable energy consumption, suggesting the feedback hypothesis, which can explain the role of renewable energy in stimulating economic growth in BRICS countries.

Control of the shape and size of iron oxide (α-Fe2O3) nanoparticles synthesized through the chemical precipitation method

Abstract: Hematite (α-Fe 2 O 3 ) nanoparticles were synthesized via a simple chemical precipitation method. The impact of varying the concentration of precursor on the crystalline phase, size and morphology of α-Fe 2 O 3 products was explored. The characteristic of the synthesized hematite nanoparticles were evaluated by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FT-IR) spectroscopy, Raman spectroscopy, Differential Thermal Analysis (DTA), Thermo Gravimetric Analysis (TGA), Ultraviolet–Visible (UV–Vis) analysis and Photoluminescence (PL). XRD data revealed a rhombohedral (hexagonal) structure with the space group R -3 c in all samples. Uniform spherical like morphology was confirmed by TEM and SEM. The result revealed that the particle sizes were varied between 21 and 82 nm and that the increase in precursor concentration (FeCl 3 , 6H 2 O) is accompanied by an increase in the particle size of 21 nm for pure α-Fe 2 O 3 synthesized with [Fe 3+ ] = 0.05 M at 82 nm for pure α-Fe 2 O 3 synthesized with [Fe 3+ ] = 0.4 M. FT-IR confirms the phase purity of the nanoparticles synthesized. The Raman spectroscopy was used not only to prove that we have synthesized pure hematite but also to identify their phonon modes. The thermal behavior of compound was studied by using TGA/DTA results: The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. Besides, the optical investigation revealed that samples have an optical gap of about 2.1 eV and that this value varies as a function of the precursor concentration.

Al-doped ZnO for highly sensitive CO gas sensors

Abstract: Al-doped ZnO (AZO) nanoparticles have been prepared using a modified sol–gel technique The as-prepared AZO nanoparticles were annealed at 400 °C, and their morphologies and microstructural characteristics were investigated using transmission electron microscopy (TEM) and x-ray powder diffraction (XRD) analyses Crystallites with an average size of approximately 60–70 nm and ZnO as a primary phase were observed in all samples In addition, smaller nanoparticles (less than 5 nm) with an Al-rich structure covering the surface of larger ZnO crystallites were also noted on the Al-doped samples Chemoresistive devices consisting of a thick layer of AZO nanoparticles on interdigitated alumina substrates have been fabricated, and their electrical and sensing characteristics for carbon monoxide were investigated Al-doping provided a remarkable decrease in the electrical resistance of the sensing layer at the working temperature of the sensors (250–300 °C) The sensors based on Al-doped ZnO exhibited a higher response than the pure ZnO sample, allowing the detection of CO at sub-ppm concentrations in air The enhancement in sensing properties was discussed in terms of the characterization and electrical data

Enantioenriched Helicenes and Helicenoids Containing Main-Group Elements (B, Si, N, P).

Abstract: In this review, we discuss the rich chemistry of helicenes and helicenoids containing main-group elements. Enantioenriched helicenic derivatives containing main-group elements B, Si, N, and P, either incorporated within the helical backbone or grafted to it, will be thoroughly presented. We will describe their synthesis, resolution, and asymmetric synthesis, their structural features, electronic and chiroptical properties, and emission, together with other photochemical properties and applications.