186 research outputs found
The Obama administration and the Israeli-Palestinian conflict. Exploring the ideational and structural factors
This study discusses the Obama Administration’s Policy toward the Palestinian- Israeli conflict from 2009 to 2017. It is an attempt to explain the change in the Administration’s approach to the peace process, and the reasons for its inability to achieve a breakthrough in resuming the negotiations between Palestinians and Israelis. Deploying the foreign policy analysis, the study explores the main drivers and outcomes of the American policy concerning the conflict and explains its development over the eight years of Obama’s presidency that started with high expectations on resolving the conflict and ended with prevailing disappointment and fear of the end of the peace process itself
Physico-chemical behaviors of shale/fluid/solute interaction in geo-environmental and geo-engineering applications.
This dissertation examines the rich and complex physical-mechanical behaviors exhibited by shales when exposed to differing solutions over time, temperature, chemical, and stress conditions. Using several unique experimental designs and numerical modeling, this study advances the level of understanding of time dependent shale behavior arising from changes in clay mineral structure and crystalline phase.The flux of water and ions over time due to semi-permeable membrane properties of shale and very fine-grained material has been numerically modeled. The purposes of this model are to predict the flux of fluid and ions through natural geological fine-grained and clay-rich materials over time and to predict the effect of this flux on long-term shale membrane behaviors. The required input parameters for the model, including water activity of both interfacial chemical fluid and the pore-fluid of the membrane, membrane properties (reflection coefficient, porosity, hydraulic conductivity, mineral compressibility, diffusion processes), and temperature and pressure conditions, were determined by laboratory work on Pierre Shale using High-Temperature High-Pressure (HTHP) Shale Apparatus. Results of this model reveal that, due to the flux of solute through the semi-permeable membrane, the shale's pore fluid activity will reduce through time, leading to a reduction in the ideality of the membrane. Given enough time (depending on the activity of the chemical used and the membrane thickness and permeability), the chemical and hydraulic difference across the membrane will disappear, leading to a diminishing of the osmotic fluid flux. This model can help in correlating and representing the semi-permeable membrane behavior of fine-grained and clay-rocks, and enhance understanding of the relevant processes. The implications for geo-environmental exploitation of the membrane properties of shales are discussed in light of these results. (Abstract shortened by UMI.)Artificial dewatering of shales is a method to eliminate shale related problems such as wellbore stability, swelling, and soil instability that produces landslides. In this dissertation, the semi-permeable membrane behavior of shale, permitting osmotic flux of fluid to the partial exclusion of ions, has been studied as a means to dewater shales exposed to chemical solutions with ion activities less than that of the in situ shale pore fluid
Marine propeller roughness penalties
PhD ThesisThe main objective of the project is to investigate the influence of
surface roughness of marine propeller blades on propulsive power. The
work has involved studies in the concept and practice of surface
roughness measurement and characterisation as well as application of
boundary layer theory for the analysis
propeller-ship hull flow interaction
of propeller flow and propellar-ship hull flow interaction. From extensive measurements of the surface topography of in-service
propellers, a standard measurement procedure using different commercially
available propeller-surveying instruments is described.
A development of turbulent boundary layer procedures has been made to
determine sufficiently accurately the increment of drag coefficient of
propeller blade sections due to propeller blade surface roughness. The
roughness function used for this integral boundary layer analysis is
derived using, principally, Musker's experimental data.
In addition, an experimental determination of the roughness function
of a replicated propeller surface using a rotor apparatus has been
carried out and described in detail.
The turbulent boundary layer procedures require a knowledge of the
surface variation of pressure over the propeller blade. For this purpose
a program based on Riegels method has been used to give the velocity
distribution for a given propeller section geometry. This is used with
the boundary layer procedures for developing a complete program
"PROFNESS" to calculate the increment of drag coefficient of the blade
section. Results from different propellers analysed indicate that the
power penalty is proportional to the relative blade roughness to the 1/3
power.
An investigation has been made to compare the increment of frictional
coefficient for a flat plate and propeller section profiles. It is shown
that a "rough" flat plane calculation is quite adequate for such work.'
The use of a flat plate analogue as a reference to calculate the skin
friction resistance of both propeller and hull surfaces is considered.
It is shown that the proposed solution of flat plate momentum integral
equations provides a valid, simple and practical solution to the problem
of predicting the hull and propeller roughness drag penalties. It also
provides, particularly for ship hull resistance, a strong support for the
ITTC Correlation Line, not only, and importantly, in regard to its slope,
but also its level.
For shipowners and operators who may not wish to access advanced
computer programs, a simplified method has been proposed to calculate the
propeller roughness penalties. There is a good agreement between the two
simplified and detailed propeller analysis methods.
The propeller roughness penalties, which can be obtained from either
the simplified or the more rigorous method, can be related to the Rubert
Propeller Comparator Gauges in order to quantify the benefits and justify
the cost of the blade surface roughness.
Analytical procedures have been included which can be used to
calculate the combined effects on ship performance of propeller blade and
ship hull surface roughnesses.Egyptian Government:
1983/84 & 1984/85 ORS Awards from the Vice-Chancellors and Principals of
the Universities of the United Kingdom
DEVELOPMENT AXES AS A CATALYST FOR REVIVING THE UN-INHABITED NEW URBAN COMMUNITIES EGYPTIAN WESTERN NORTH COAST DEVELOPMENT AXIS
Using the Brink Depth in Discharge Measurement for Inverted Semicircular Open Channels
A free overfall at the end of an open channel provides a simple means for measuring flow discharge. The semicircular open channel plays a significant role in various applications, and it is of interest to calculate its discharge. This paper presents the application of the momentum equation to evaluate the use of a smooth inverted semicircular channel end as devised to calculate the discharge if the end depth is known. The experiments were performed in three separate semicircular inverted channels, with diameters of 15.0 cm, 18.4 cm, and 24.2 cm. The experimental data used to develop equations for calculating the discharge from known end depth. Where the end depth is related to the critical depth, and the end depth ratio value was found to be 0.8102 for a critical depth-diameter ratio of up to 0.40. On the other hand, the relationships for end depth ratio and non-dimensional discharge are defined. Two empirical equations are generated for the direct and indirect prediction of discharges from known end depth values
Effect of Propolis as Additive on Some Behavioural Patterns, Performance and Blood Parameters in Muscovy Broiler Ducks
Forty Muscovy ducklings of one day old were used in this study. They were brooded together for 3 weeks and then were randomly divided into two groups, 20 ducklings per each. Each group was housed in a well ventilated, previously cleaned, disinfected and well bedded with saw dust 3 x 3 m pen. Birds were maintained at 33 °C using gas heater and the temperature was gradually reduced by 3 °C / week until 21 °C was reached and then continued to the end of the experiment. Continuous lighting program with 23 hours light to one hour dark was maintained by the natural day light and a 60 watt bulb that placed centrally in each pen at 2 meters height above the heads of birds. Birds were daily fed ad-libitum on a commercial duck broiler starter ration up to 3 weeks of age and on a duck broiler grower finisher ration till 12 weeks old. The first group was fed on these diets without any supplements and used as a control group, however, the second one was fed the finisher rations provided and thoroughly mixed with ethanol extracted propolis at a rate of 2 gm / Kg of diet. Water was freely available allover the experiment. Behaviour, performance and blood parameters of the experimented birds were carried out. Obtained results indicated that use of propolis as a natural feed additive reflected on ducks with a reduction in stress behaviour, increased growth performance, increased immune response and resistance and improved welfare through improving the physical health state
Editorial: biomarkers in neurology
Neurological disorders constitute a major health and socioeconomic problem. They represent the second cause of death and the leading cause of disability throughout the world. Despite the implementation of strategies and intervention programs to reduce the burden, over the past 25 years, the incidence, prevalence, mortality, and disability rates of neurological disorders are rising globally, mainly due to population aging and growth (1). This has placed heavy pressure on health-care systems pointing out the urgent need to identify new strategies to improve patient outcomes and reduce health costs by enabling more effective drug development and establishing a more personalized medicine approach.
Rapid scientific and technical advances have enabled reliable and affordable measurement of novel biomarkers—biological indicators that objectively measure and evaluate physiological or pathophysiological processes or pharmacological responses to a therapeutic intervention (2)—which have been suggested to help assessment and management of patients with neurological disorders beyond current practice standards (3–5). Evidence suggests a potential variety of clinical applications, including enhancing diagnostic and prognostic accuracy, improving the existing decision criteria for early diagnosis and risk stratification, as well as assisting in disease monitoring, and acting as surrogate endpoints in experimental studies and clinical trials (6–10). In addition, biomarkers may reliably capture the different aspects of disease heterogeneity and pathogenesis, helping characterize patients, and thereby informing targeted tailored treatments and predicting response outcomes to interventions (11–18). However, despite large numbers of candidate biomarkers have been proposed and extensively evaluated, very few are currently integrated into routine clinical practice and the quest for novel brain injury markers in still ongoing (19)
Assessment of coronary heart diseases in diabetics in al-Madinah al-Munawarah
Omar al-Nozha1, Moaz Mojadadi2, Mohamed Mosaad1,3, Mohamed F El-Bab2,41Department of Medicine, 2Department of Physiology, College of Medicine, Taibah University, al-Madinah al-Munawarah, Kingdom of Saudi Arabia; 3Department of Medicine, 4Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, EgyptBackground: Coronary heart disease is highly prevalent and a major cause of morbidity and mortality in diabetic patients. The aim of this study was to assess the major risk factors and their predictor score for coronary heart diseases in diabetic patients.Methods: The present study was conducted in al-Madinah, Kingdom of Saudi Arabia. Using a cross-sectional case control study, 262 outpatient diabetics and 264 matched control subjects were examined for the risk factors and risk predictor scores for ischemic heart disease. The mean age of the patient and control groups was 49.61 ± 12.93 years and 48.39 ± 11.60 years, respectively.Results: Diabetic patients had significantly higher positive family history of diabetes, but no significant difference regarding their family history of hypertension. There was a significantly higher body mass index (33.67 kg/m2), glycosylated hemoglobin (7.26%), significantly higher cholesterol, low-density lipoprotein, and triglyceride in diabetics compared to control. Diabetic patients had higher risk for developing coronary heart disease with a mean risk score of 6.07 while the control subject risk score was -6.81. However, females showed significantly higher risk for coronary heart diseases than did males.Conclusion: Our study replicates the known fact of higher risk in diabetes, but higher risk of coronary heart disease in female diabetics compared with male diabetics.Keywords: coronary heart disease, risk factors, diabetes mellitu
Adaptive Neuro Fuzzy Technique for Speed Control of Six-Step Brushless DC Motor
The brushless DC motors with permanent magnets (PM-BLDC) are widely used in a miscellaneous of industrial applications. In this paper, The adaptive neuro fuzzy inference system (ANFIS) controller for Six-Step Brushless DC Motor Drive is introduced. The brushless DC motor’s dynamic characteristics such as torque , current , speed, , and inverter component voltages are showed and analysed using MATLAB simulation. The propotional-integral (PI) and fuzzy system controllers are developed., based on designer’s test and error process and experts. The experimential and hardware resuts for the inverter- driver circuits are presented. The simulation results using MATLAB simulink are conducted to validate the proposed (ANFIS) controller’s robustness and high performance relative to other controllers
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