STRUCTURAL STYLE AND TECTONIC EVOLUTION OF THE NORTHWEST SIRT BASIN–CRETACEOUS- TERTIARY RIFT, LIBYA

The Cretaceous-Tertiary northwest-trending Sirt Basin system, Libya is a rift/sag basin formed on Pan-African to Paleozoic-aged basement of North Africa. This study is an investigation of the rift-basin architecture and tectonic framework of the western Sirt Basin. A combination of several geological and geophysical methods (remote sensing interpretation supported by surface geologic maps, borehole data analysis, from about 300 deep wells, extensive seismic reflection profiles and maps, and paleostress analysis), have been used to construct geological cross sections, and surface and subsurface geology maps that have proved particularly useful in identifying various regional and local structures in the study area. Indication of the relative timing of structures and movement along faults has been determined where possible. We recognize six lithostratigraphic sequences (phases) in the area's stratigraphic framework. A Pre-graben (Pre-rift) initiation stage involved the Pre-Cretaceous sediments formed before the main Sirt Basin subsidence. Then followed a Cretaceous to Eocene graben-fill stage that can divided into four structurally-active and structurally-inactive periods, and finally a terminal continental siliciclastics-rich package representing the Eocene post-rift stage. Late Eocene rocks exposed in the western part of the basin exhibit a complex network of branching segmented normal and strike-slip faults, generally with a NNW-SSE structural grain. Many surface structural features have been interpreted from satellite images which confirm sinistral strike-slip kinematics. Relay ramp structures, numerous elongate asymmetric synclines associated with shallow west limbs and steeper dipping east limbs are developed in the hangingwalls adjacent to west downthrowing normal faults. These structural patterns reflect Cretaceous/Tertiary extensional tectonics with additional control by underlying pre-existing Pan-African basement fabrics and ENE-WSW trending Hercynian structures. The interpretation of a large volume of two-way time seismic data has allowed the construction of long regional seismic cross sections and resultant time structure contour and thickness maps, thus enabling an understanding of the structural and stratigraphic relationships on a regional scale. Six major fault systems were identified initially from the remote sensing study and was subsequently expanded to seven on the basis of interpretation of 2D seismic data. These fault systems dissect the study area into geomorphological elevated blocks and depressions. Most of the oil fields present in the study area are associated with structural hinge zones and adjoining highs. A new kinematic and structural conceptual model is proposed here for the evolution of NW Libya (Jifarah Basin and the Nafusah Uplift) and Hun Graben during Late Eocene times. The multidisciplinary approach used in this study has resulted in good surface and sub-surface structure correlation and future petroleum prospectivity has been identified in this study. We relate the Sirt Basin rift development as exemplified in our study area to the break-up of Gondwana represented by the structural evolution of the West-Central African rift system and the South and Central Atlantic, the Tethys and the Indian Oceans

Information systems evaluation: Mini-track introduction

abreast of technological innovations. Yet, companies are becoming more aware that a competitive advantage can not be achieved, or even maintained by utilizing the latest technology. Indeed, it is becoming more apparent that a strategic competitive advantage will not be achieved through embraced technology alone but, in the way companies approach the evaluation, management and exploitation of their human, organizational and technology based assets and infrastructure. In support of this, Sohal et al. (2001) reported the results of a large-scale survey that demonstrated the limited Information Technology (IT) enabled business benefits resulting in service and manufacturing sectors. The survey highlighted that many of the benefits achieved through adopting IT/IS were limited to improvements in productivity and cost alone. Clearly, such results are surprising given the emphasis the normative literature has placed on the strategic benefits achievable from IT/IS. As a result of the far reaching conclusions reported by Sohal et al. (2001), many organisational have begun to question the scope and depth of those IT-enabled business benefits that are not achieved by those companies proactively adopting IT/IS

Two-phase slug flow measurement using ultra-sonic techniques in combination with T-Y junctions

The accurate measurement of multiphase flows of oil/water/gas is a critical element of oil exploration and production. Thus, over the last three decades; the development and deployment of in-line multiphase flow metering systems has been a major focus worldwide. Accurate measurement of multiphase flow in the oil and gas industry is difficult because there is a wide range of flow regimes and multiphase meters do not generally perform well under the intermittent slug flow conditions which commonly occur in oil production. This thesis investigates the use of Doppler and cross-correlation ultrasonic measurements made in different high gas void fraction flow, partially separated liquid and gas flows, and homogeneous flow and raw slug flow, to assess the accuracy of measurement in these regimes. This approach has been tested on water/air flows in a 50mm diameter pipe facility. The system employs a partial gas/liquid separation and homogenisation using a T-Y junction configuration. A combination of ultrasonic measurement techniques was used to measure flow velocities and conductivity rings to measure the gas fraction. In the partially separated regime, ultrasonic cross-correlation and conductivity rings are used to measure the liquid flow-rate. In the homogeneous flow, a clamp-on ultrasonic Doppler meter is used to measure the homogeneous velocity and combined with conductivity ring measurements to provide measurement of the liquid and gas flow-rates. The slug flow regime measurements employ the raw Doppler shift data from the ultrasonic Doppler flowmeter, together with the slug flow closure equation and combined with gas fraction obtained by conductivity rings, to determine the liquid and gas flow-rates. Measurements were made with liquid velocities from 1.0m/s to 2.0m/s with gas void fractions up to 60%. Using these techniques the accuracies of the liquid flow-rate measurement in the partially separated, homogeneous and slug regimes were 10%, 10% and 15% respectively. The accuracy of the gas flow-rate in both the homogeneous and raw slug regimes was 10%. The method offers the possibility of further improvement in the accuracy by combining measurement from different regimes

Antimicrobial, antioxidant and phytochemical investigation of Balanites aegyptiaca (L.) Del. edible fruit from Sudan

The methanol extract of the fruit (edible mesocarp) of Balanites aegyptiaca (L.) Del., a popular plant from Sudan, widely employed in Sudanese folk medicine was screened for antimicrobial, antioxidant and some active phytochemical compounds. The extract showed the presence of saponin, terpenoids, phenolic compounds and alkaloids. The methanolic extract of the fruits extracted from B. aegyptiaca exhibited a strong antioxidant activity in the DPPH assay and a potent capacity in preventing linoleic acid oxidation. Methanol extracts (50 and 100 mg/ml) were tested on several microbial strains using agar-well diffusion, minimum inhibitory concentration (MIC), minimum bacterial concentration (MBC) and minimum fungal concentration (MFC) methods. These experiments were performed on ten bacterial strains (five Gram-positives and five Gram-negatives) and four fungal strains. Methanol extracts, particularly at concentration of 100 mg/ml was found to be active against all bacterial and fungal strains and it was comparable to standard antibiotics Gentamicin and Amphotericin B. These findings support some of the traditional applications of the fruit of B. aegyptiaca against microbial aliments. It is therefore recommended that further studies regarding fractionation, separation and purification of these active antimicrobial compounds are required, in addition to toxicological evaluation in vivo.Key words: Balaneties aegyptiaca, antibacterial, antifungal, phytochemical, antioxidant, methanol extract

Clinical and echocardiographic features of children with rheumatic carditis: correlation with high sensitivity C-reactive protein.

Background: Rheumatic fever (RF) and rheumatic heart disease (RHD) are leading causes of cardiovascular mortality and morbidity in developing countries.Objectives: To describe the clinical and echocardiographic features of children with RF and RHD and compare these features with their serum C-reactive protein in 2 pediatric cardiology centers in Khartoum.Methodology: It was a prospective cross sectional study. Patients were examined clinically and by echocardiography. Serum high sensitivity C-reactive protein (hsCRP) was measured from children with Acute RF as well as from healthy age and sex matched controls selected from children attending the clinics. Statistical Analysis Used: Mean and standard deviation, P value using Fisher’s exact test.Results: Sixty six patients (45% males) were enrolled. Mitral regurgitation (MR) was found in 65 patients (98%), it was severe in 42 patients (64%), combined with aortic regurgitation (AR) in 27 patients (41%) and with Mitral stenosis (MS) in 3 patients (4.5%). For patients with carditis, hsCRP ranged between 1.10 and 15 mg/l (mean 8.0817, SD 4.47). In the control group it was 0.6-1.3 mg/l (mean 0.93 SD 0.23) P<0.0001.Patients with Acute RF had hsCRP mean of 12.35 mg/l (SD 2.11) while those with chronic RHD had hsCRP mean of 7.34 mg/l (SD 4.16), P<0.0001.Conclusion: RHD is manifested in our patients with severe valve damage dominated by MR and there is evidence of an ongoing inflammation during the chronic phase. RHD is manifested in a severe form in Sudan. High sensitivity CRP is elevated in acute phase as well as in the chronic phase.Key Words: Rheumatic carditis, C-reactive protein