The groundwater aquifers in Azintan, northwestern Libya suffer from an acute shortage of water. The groundwater was evaluated to determine its suitability for drinking and irrigation purposes from major two aquifers in north and south of Azintan area. This study carried out to assess the groundwater quality and to identify major affecting variables. Twelve samples from the two aquifers were collected. The two aquifers were collected and analyzed for total dissolved solid (TDS), electrical conductivity (EC), pH, Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl^-, SO4^2-, CO3^2- and HCO3^-. The results show that, the groundwater in many places is dominated by higher concentrations of Cl^-, SO4^2- and HCO3^-. Two water types were recognized in this region are Cl-SO4- Na-Ca and Cl-SO4-Na. Gibbs and Piper method, as well as the hardness, soluble sodium percentage and the permeability index all have been used to assess the diagram quality of the groundwater of aquifers. Further, the multiple correlations and Cluster Analysis of groundwater quality parameters were carried out for further classification and interpretation of the groundwater quality. Finally, water qualities in the study area are compared with Libyan standards and WHO guidelines of drinking water and irrigation  purposes.

Technology has become an essential part of education today, and learning environment has changed from that of many years ago; students need to use technology as an alternative effective learning tool for learning English language as a foreign language (EFL). Most of current studies in the educational use of social media seem to pay more attention to the students' use of Facebook in learning. This research explores 14 university learners use of Facebook group and it mainly focuses on lecturers' role in Facebook group. This qualitative study involved observation and some interview questions. Current findings highlight that there are potential benefits to using Facebook for learning with reference that these students still need a guideline and support from their lecturers to learn English via Facebook. This paper suggests that considerable students' content knowledge of educational technology as Facebook is required to improve their learning. This study hopes to add and expand current body of knowledge about learning English in relation to Facebook used in English foreign language context. 

SUMMARY

This thesis entitled comprises four chapters and ends with alist of references.

The first chapter covers the literature up to date of the reaction of nucleophilic substitution reactions and their different mechanisms.then describes .of preparation of the methods

the procedure used to determina the rate constant for the reaction and kinetic data

then deals the discussion and interpretation of the results from the above mentioned reaction .

application of Hammett relationship . and application of Bronsted equation

Abstract:

Nepeta cyrenaica Quézel & Zaffran (Lamiaceae), an endemic species of Libyan flora, is here characterized for the first time for its phytochemical composition and biological activities. Phenolic composition, antioxidant and enzyme inhibiting effects of extracts, prepared from five-week-old in vitro propagated N. cyrenaica shoots, were evaluated. Extraction was performed using dichloromethane, methanol, 96% ethanol or hot distilled water. LC-MS analysis showed that the methanol extract contained the highest amount of phenolic components, especially ferulic and rosmarinic acids (1300.73 mg/kg and 528.88 mg/kg, respectively), and epigallocatechin gallate (719.05 mg/kg). The strongest antioxidant activity was recorded for aqueous extract in DPPH assay (66.91%) and dichloromethane extract in β-carotene bleaching assay (81.06%), both tested at the concentration of 2 mg/mL. Concerning α-glucosidase inhibition, dichloromethane extract was shown to possess a higher inhibition capacity than acarbose at the concentration of 2 mg/mL (95.33% vs. 88.29%). The aqueous extract exhibited higher acetylcholinesterase inhibition than the other tested extracts, which was lower compared to the positive control, galantamine. Although methanol extract contained the highest amount of polyphenolics, dichloromethane and aqueous extracts were shown to be more suitable for the extraction of bioactive components. In conclusion, endemic N. cyrenaica could be efficiently propagated through in vitro propagation protocols as a polyphenolic-rich plant with valuable medicinal potential.

Keywords: biological activities; extracts; in vitro propagation; Nepeta cyrenaica

This study considers the diagenetic processes and the depositional settings of Lower Jurassic gypsum of the Bi'r Elghanem Formation in the northwestern of Libya. The paleo-environment study has revealed a variety of depositional environment ranging from lagoonal to fluvial deposit and evaporitic basins, which become intensely saline as a result of evaporation due to (semi-) arid environments. Samples were analyzed using elemental analysis, statistical evaluation such as Multiple Correlations, Principal Component Analysis, and mineralogical evidence to determine their mode of environmental deposition, mineralogical and geochemical composition. The geochemical results indicate that gypsum has evidence of mineral substitutions and displacement, suggesting a homologous mechanism for lithofacies and subsequent textural change. The development of gypsum minerals in a variety of lithologies and textures is aided by eustatic fluctuations in lake water level due to regional tectonism and climate.

Lithostratigraphically, the Sidi As sid Formation (Upper Cretaceous) in the El Zintan section (JabalNafusah, NW Libya) consists of three units: upper marl, middle marl with intercalations of dolostone, and lower dolostone. Based on crystal size and shape, three types of dolomite have been classified. Fine crystalline dolomite (D1) consists of nonplanar dolomites, fine to medium crystalline dolomite (D2), and very coarse, consisting of mostly planar dolomites (D-3). The Cathodoluminescence technique also showed that most of these dolomites have bright yellow to red and dull orange luminescence and zoning. Based on X-ray diffraction (XRD), all dolomites are relatively well ordered and non to nearly stoichiometric dolomite. The stable isotopic studies and element analysis show that the major elements such as sodium (D1: 412.166 ppm; D2: 175 ppm; D3: 420 ppm), strontium (D1: 107 ppm; D2: 85 ppm; D3: 81.2 ppm), manganese (D1: 271 ppm; D2: 91 ppm; V3: 242 ppm), and iron (D1: 4856.66 ppm; D2: 373 ppm; D3: 3287 ppm) and the values of the stable isotope of oxygen (D1:-2.202‰; D2:-2.131; D3:-4.359‰) and carbon (D1: 2.080; D2: 2.076‰; D3: 1.581‰). The values of major elements and depletion of the carbon and oxygen isotopes can be related to the effects of temperature diagenetic, and mesosaline reflux of dolomitizing fluids during the early diagenesis. These dolomites originated in a tidal environment in this Formation. The major sources of magnesium for the dolomites are seawater and hypersaline fluids.