Tunis University

About: Tunis University is a education organization based out in Tunis, Tunisia. It is known for research contribution in the topics: Population & Thin film. The organization has 11745 authors who have published 15400 publications receiving 154900 citations. The organization is also known as: University of Tunis & UT.

Diagenesis and formation water chemistry of Triassic reservoir sandstones from southern Tunisia

Abstract: The fluvial Triassic reservoir subarkoses and arkoses (2409·5–2519·45 m) of the El Borma oilfield, southern Tunisia, were subjected to cementation by haematite, anatase, infiltrated clays, kaolinite and K-feldspar at shallow burial depths from meteoric waters. Subsequently, basinal brines controlled the diagenetic evolution of the sandstones and resulted initially in the precipitation of quartz overgrowths, magnesian siderite, minor ferroan magnesite and anhydrite. The enrichment of siderite in 12C isotope (δ13CPDB= - 14·5 to - 9‰) results from derivation of carbon from the thermal decarboxylation of organic matter. During further burial, the precipitation of dickite and pervasive transformation of kaolinite into dickite occurred, followed by the formation of microcrystalline K-feldspar and quartz, chlorite and illite, prior to the emplacement of oil. Present day formation waters are Na-Ca-Cl brines evolved by the evaporation of seawater and water/mineral interaction and are in equilibrium with the deep burial (≤ 3·1 km) minerals. These waters are suggested to be derived from the underlying Silurian and Devonian dolomitic mudstones.

Impact of ZnO addition on structural, morphological, optical, dielectric and electrical performances of BaTiO 3 ceramics

Abstract: BaTiO3/(ZnO)x ceramics (x = 0, 2, 5 and 10 wt%) were produced via solid state reaction by using high energy ball milling. The morphological, structural, spectral, optical, electrical and dielectric properties were systematically investigated. X-ray diffraction indicated that all ceramics crystallize in the tetragonal structure. The grains size increases with ZnO additions. The optical band gap energy (Eg) was also evaluated and found to reduce with increasing ZnO concentration. The dielectric and electric properties revealed that an optimal ZnO content lead to obtain ceramic with high dielectric constant and low tangent loss, which are encouraging for radio frequencies and microwaves applications.

Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation

Abstract: Load transfer of the graphene/carbon nanotube (CNT)/polyethylene hybrid nanocomposite is studied here from molecular dynamics (MD) simulations Simulations of this composite material under uniaxial tension were conducted by varying CNT’s position and diameter in the polymer matrix The obtained results show that: (1) The peak strength of stress and strain evolution in the polymer matrix is lower than the peak strength of the graphene/graphene and graphene/polymer interfaces Hence, the damage zone is always located in the polymer matrix (2) Agglomerated two-layer graphenes do not possess an increased value in the peak strength compared with single-layer graphene-reinforced polymer nanocomposite (PNC), while two separate layers of graphene show slightly higher peak strength (3) The largest peak strength is observed before CNT moves to the center of the polymer matrix The damage location moves from the upper to the lower part of CNT when the CNT is located at the centre of polymer matrix (4) The influence of the CNT diameter on the peak strength is not obvious, while the damage location and shape in the polymer matrix changes with respect to varying CNT diameters In addition, the damage zone always falls outside the interphase zone