Time filter

Source Type

Hamada G.M.,United Arab Emirates University | Almajed A.A.,King Fahd University of Petroleum and Minerals | Okasha T.M.,Saudi Aramco | Algathe A.A.,Hadhramout University
Journal of Petroleum Exploration and Production Technology | Year: 2013

Reservoir evaluation is one of the critical tasks of any reservoir exploration and field development plan. Water saturation calculated from open-hole resistivity measurements is a primary input to hydrocarbon reserves evaluation. Archie's equation is the water saturation model for the determination of water saturation. Application of Archie equation in carbonate reservoir is not easy due to high dependency of its parameters on carbonate characteristics. Determination techniques of Archie's parameters are relatively well known and validated for sandstone reservoirs, while carbonates are heterogeneous and a correct estimation of Archie' parameter is important in their evaluation. In the case of carbonate rocks, there are considerable variations in texture and pore type, so, Archie's parameters become more sensitive to pores pattern distribution, lithofacies properties and wettability. Uncertainty in Archie's parameters will lead to non-acceptable errors in the water saturation values. Uncertainty analysis has shown that in calculating water saturation and initial oil in place, the Archie's parameters (a, m, n) have the largest influence and Rt and Rw are the least important. The main objective of this study was to measure Archie's parameters on 29 natural carbonate core plugs at reservoir conditions, using live oil, these core samples were taken from three wells. For this purpose, three techniques were implemented to determine Archie's parameters; conventional technique, core Archie's parameters estimate technique and three-dimensional technique. Water saturation profiles were generated using the different Archie parameters determined by the three techniques. These profiles have shown a significant difference in water saturation values and such difference could be mainly attributed to the uncertainty level for the calculated Archie parameters. These results highlight the importance of having accurate core analysis's measurements performed on core samples that yield representative a, m and n values that highly influence the water saturation values. © 2012 The Author(s). Source

Bin Anooz S.,Hadhramout University | Petrik P.,Research Institute for Technical Physics and Materials Science | Schmidbauer M.,Leibniz Institute for Crystal Growth | Remmele T.,Leibniz Institute for Crystal Growth | Schwarzkopf J.,Leibniz Institute for Crystal Growth
Journal of Physics D: Applied Physics | Year: 2015

The influence of lattice strain on the refractive index and optical band gap of NaNbO3 thin films, deposited by the liquid-delivery spin metalorganic chemical vapor deposition method, was investigated by spectroscopic ellipsometry. Epitaxial growth of coherently strained NaNbO3 films was confirmed by high-resolution x-ray diffraction and transmission electron microscopy. Incorporated lattice strain in the films was varied by the use of the oxide substrates NdGaO3, SrTiO3 and DyScO3, which exhibit lattice mismatches to NaNbO3 with different sign, magnitude and anisotropy. The Sellmeier dispersion was employed to analyze the ellipsometry data in energy region of 1.49-2.75 eV. The refractive index at 632.8 nm of the pseudomorphically grown NaNbO3 films critically depends on the incorporated elastic lattice strain and results in a continuous decrease from 2.46 to 2.18 by varying the in-plane strain from compressive to tensile. Band gap energies for films grown under compressive and tensile lattice strain were determined by collecting spectroscopic ellipsometry data in a larger energy range between 0.73-6.48 eV and evaluating them by the Tauc-Lorentz dispersion. We observed that for tensily strained NaNbO3 films deposited on DyScO3 and SrTiO3, the band gap energies increased to and eV, respectively. For the compressively strained NaNbO3 film deposited on NdGaO3 the band gap is shifted to still higher energies ( eV). © 2015 IOP Publishing Ltd. Source

Bayagoob K.H.,Hadhramout University | Noorzaei J.,University Putra Malaysia | Jaafar M.S.,University Putra Malaysia | Thanoon W.A.,The University of Nizwa | Abdulrazeg A.A.,University Putra Malaysia
Proceedings of the Institution of Civil Engineers: Engineering and Computational Mechanics | Year: 2010

Temperature control plays an important role in the design and construction of roller-compacted concrete (RCC) dams. Hydration of cement and climatic changes on the convective boundaries are the two main heat sources of the temperature rise in RCC dams. Therefore, the effects of these two factors have to be determined accurately in order to reduce the risk of thermally induced cracking in these dams. Simplified approaches are usually adopted to approximate the temperature changes on the upstream dam side after the dam reservoir is filled. These simplified approaches are usually based on long-term observations of similar reservoirs. However, it is practically hard to generalise the conditions of these reservoirs with respect to the reservoir under consideration. In this work, the finite-element method has been used to simulate the heat exchange between the RCC dam body and the reservoir water taking into account the reservoir operation. A realistic isothermal profile has been obtained that has been used to determine the cracking probability of the RCC dam body. Source

Banafa N.S.,Hadhramout University
Bahrain Medical Bulletin | Year: 2015

Background: There are only a few studies about the causes of mortality among critically ill patients in Intensive Care Unit (ICU). Objective: To determine the main causes of death among critically ill patients in ICU. Design: A Retrospective Study. Setting: Ibn Sina Teaching Hospital, Hadhramout Province, Yemen. Method: A retrospective study was conducted in mixed medical-surgical 12-beds Intensive Care Unit from 1 January 2013 to 31 December 2013. Data were collected from the medical records and analyzed using SPSS version 14. Result: Five hundred one patients were included in the study. The mean age of death was 60.35% (years) and the most common causes of death were from circulatory system disorders 215 (42.91%), followed by 99 (19.76%) renal failure. Most patients were in the age group of ≥70 years at the time of death; average hospitalization was 1-7 days. There was a significant statistical relationship between the death in ICU with the age and length of stay (P =.0001). Conclusion: Circulatory system disorders and renal failure were the most common causes of death among the critically ill patients in the ICU. © 2015, Bahrain Medical Bulletin. All rights reserved. Source

Bin-Thalab R.,Hadhramout University | El-Tazi N.,Cairo University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Managing temporal data gets increased demand for many significant areas such as scientific and financial applications. This paper proposes a new index (TOIX), which is designed in order to provide more efficient evaluation of temporal queries on XML documents. The index lies on mapping the twigs into temporal objects and then using these objects instead for answering the query. An improvement of the naive algorithm using a B-tree as well. Finally, a set of conducted experiments were performed and showed that our proposed algorithm outperforms the state of the art indexing algorithms in certain cases. © Springer International Publishing Switzerland 2015. Source

Discover hidden collaborations