647 research outputs found

    NASA Lewis F100 engine testing

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    Two builds of an F100 engine model derivative (EMD) engine were evaluated for improvements in engine components and digital electronic engine control (DEEC) logic. Two DEEC flight logics were verified throughout the flight envelope in support of flight clearance for the F100 engine model derivative program (EMPD). A nozzle instability and a faster augmentor transient capability was investigated in support of the F-15 DEEC flight program. Off schedule coupled system mode fan flutter, DEEC nose-boom pressure correlation, DEEC station six pressure comparison, and a new fan inlet variable vane (CIVV) schedule are identified

    Science as a Subject of Learning in Islamic University

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    This paper aims to searching theological impact when applied a science as a subject of learning at Agrotechnology Department in the Faculty of Sciences and Technology of State Islamic University of Bandung. The atmospheric experiment was implemented as a subject of learning. By observing the atmospheric data recorded, the plant growth measured significantly affected by the implementation of treatments, the best water supply and fertilizer application. Furthermore, it found that local climate has changed, and Schmidt and Ferguson classification of regional rain types is no more valid, thus, should be renewed. The experiment impacted to a science learning program in Islamic University. Climatic change is a natural law affected by human destructed to the nature. It has been affecting farmers to maintain for their plantation activities. When organisms were effort to surviving in warmer and unpredictable condition, that is shows to human kind has to obligatory to the Almighty God

    Performance and stall limits of an afterburner-equipped turbofan engine with and without inlet flow distortion

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    Performance and stall limits of afterburner-type turbofan engine with and without inlet flow distortio

    Adherence of Healthcare Professionals to Evidence-based Clinical Practice Guidelines in the Management of Hemodialysis Patients, Khartoum State, Sudan

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    Introduction: Hemodialysis (HD) is a complex procedure with many specifications and requires adherence to a set of particular clinical practice guidelines. These guidelines had already been established by globally acclaimed renal authorities and their implementation was shown to correlate with patients’ morbidity and mortality. This study was conducted to evaluate the adherence of healthcare professionals to the evidence-based clinical practice patterns in Khartoum State HD units.Methods: A cross-sectional study was conducted in Khartoum State HD units during the period from September 2010 to January of 2011. Data was collected from the healthcare professionals using a specially designed checklist. The checklist included the evidence-based clinical practice guidelines for the HD vascular access, HD adequacy, anemia of chronic kidney disease (CKD), nutrition, cardiovascular risk assessment, and hepatitis B and C virus infection control. Implementation of these guidelines was evaluated, and further graded using a Likert-type scale.Results: Four randomly selected HD units were included in the study. The rate of implementation of the HD vascular access guidelines was 54.8%, adequacy guidelines 57%, anemia of CKD 68.8%, nutrition 58.4%, cardiovascular risk assessment 57%, and hepatitis B and C infection control guidelines was 79.2%. Overall, the four HD units assessed showed moderate deviations from the practice guidelines of anemia of CKD and hepatitis B and C infection control. Extreme deviations from the clinical practice guidelines were seen in HD vascular access practices, adequacy assessments, nutrition and cardiovascular risk assessment.Conclusion: Hemodialysis services in Khartoum State are in need of great improvements regarding adherence to protocols and the standards of care.Key words: Clinical practice guidelines; Hemodialysis; Suda

    A UV-Spectrophotmetric Chemometric Method for the Simultaneous Determination of Sulfadoxine and Pyrimethamine in Tablets

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    In the present study, a simple, inexpensive, precise and accurate uv-spectrophotometric method based on chemometrics, has been developed for the simultaneous determination of sulfadoxine and pyrimethamine in tablet formulation. The % recoveries obtained were 99.7% ± 0.9 and 101.5% ± 0.8 for sulfadoxine and pyrimethamine, respectively. The developed method has been compared to USP-HPLC method with regard to accuracy and precision. The calculated F-ratio and the (t) statistics indicate that there is no significant difference at 5% level with regard to precision and accuracy between the proposed and the USP methods. Moreover, the developed method is simple, cost-effective, and less time-consuming. Accordingly, it can be used advantageously in routine quality control of sulfadoxine and pyrimethamine in tablet formulation

    Seismic Microzonation of Central Khartoum, Sudan

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    A preliminary seismic microzonation of Central Khartoum, Sudan is proposed. Khartoum, the capital of Sudan, is located at the confluence of White and Blue Niles. The city is heavily populated. The Central Khartoum with its high rise buildings is the center of governmental and business activities and is located on strip adjacent to the Blue Nile. Geological and geotechnical data indicated that the subsoil conditions at Central Khartoum are characterized by alluvial deposits underlain by Nubian Sandstone below a depth of 20 m. The alluvial deposits locally known as Gezira formations, consist of clays grading into silt and sand with depth. Macro seismic zonation of Sudan and its vicinities, developed by the authors, gave the ground acceleration at the bed rock surface. The effect of alluvial deposits at Central Khartoum on propagation of seismic motion parameters to the ground surface is investigated in this study. Correlations are proposed for pertinent cyclic soil properties such as shear modulus, damping, and shear wave velocity. The classical shear beam model developed by Idriss and Seed is used to study the effect of local soil conditions on ground motion parameters. In absence of strong motion records, artificial time histories of ground motion parameters are used. Plots showing the time histories of ground motion parameters at the ground surface are obtained. The results indicated amplification of ground acceleration of up to 1.15. Because of the presence of saturated loose to medium dense sand at some locations within Central Khartoum, the risk of earthquake-induced liquefaction is evaluated. The susceplity of subsoils in Central Khartoum to liguefaction is evaluated probabilistically by modifying the classical method developed by Seed and Idriss. The risk of earthquake-induced liquefaction is computed by combining the seismic hazard and the conditional probability of liquefaction. The study showed that the risk of liquefaction is low

    Dynamical System Analysis of Cosmologies with Running Cosmological Constant from Quantum Einstein Gravity

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    We discuss a mechanism that induces a time-dependent vacuum energy on cosmological scales. It is based on the instability induced renormalization triggered by the low energy quantum fluctuations in a Universe with a positive cosmological constant. We employ the dynamical systems approach to study the qualitative behavior of Friedmann-Robertson-Walker cosmologies where the cosmological constant is dynamically evolving according with this nonperturbative scaling at low energies. It will be shown that it is possible to realize a "two regimes" dark energy phases, where an unstable early phase of power-law evolution of the scale factor is followed by an accelerated expansion era at late times.Comment: 26 pages, 4 figures. To appear in New Journal of Physic

    Hiding data in images using steganography techniques with compression algorithms

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    Steganography is the science and art of secret communication between two sides that attempt to hide the content of the message. It is the science of embedding information into the cover image without causing a loss in the cover image after embedding.Steganography is the art and technology of writing hidden messages in such a manner that no person, apart from the sender and supposed recipient, suspects the lifestyles of the message. It is gaining huge attention these days as it does now not attract attention to its information's existence. In this paper, a comparison of two different techniques is given. The first technique used Least Significant Bit (LSB) with no encryption and no compression. In the second technique, the secret message is encrypted first then LSB technique is applied. Moreover, Discrete Cosine Transform (DCT) is used to transform the image into the frequency domain. The LSB algorithm is implemented in spatial domain in which the payload bits are inserted into the least significant bits of cover image to develop the stego-image while DCT algorithm is implemented in frequency domain in which the stego-image is transformed from spatial domain to the frequency domain and the payload bits are inserted into the frequency components of the cover image.The performance of these two techniques is evaluated on the basis of the parameters MSE and PSNR
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