oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 9 )

2019 ( 714 )

2018 ( 839 )

2017 ( 762 )

Custom range...

Search Results: 1 - 10 of 462926 matches for " Yehia A. Hussein "
All listed articles are free for downloading (OA Articles)
Page 1 /462926
Display every page Item
New families of integrable two-dimensional systems with quartic second integrals
H. M. Yehia,A. M. Hussein
Physics , 2013,
Abstract: The method introduced in (Yehia H M 2006 J. Phys. A: Math. Gen. 39 5807-5824) and (Yehia H M 2012 J. Phys. A: Math. Gen. 45 395209) is extended to construct new families of several-parameter integrable systems, which admit a complementary integral quartic in the velocities. A total of 12 new systems are obtained, with a number of parameters ranging from 7 up to 16 parameters.
Acute Toxicity of Euphorbia heliscopia in Rats
S.I. AL-Sultan,Yehia A. Hussein
Pakistan Journal of Nutrition , 2006,
Abstract: Fifty two Wistar albino rats of both sexes were used for determination of the LD50 and some toxicological studies of the active principles of Euphorbia heliscopia (sun spourge). The oral LD50 was 1211.7 mg/kg. b.wt. of crude ethyl alcohol extracts under our environmental conditions. The symptoms appear on the intoxicated animals were included increase activity and irritability, salivation, itching the nose and mouth on the cage floor, and diarrhea. The animals were tried to make tunnels under the bed and they were reluctant to stand at the cage corners. Finally the animals closed its eyes and become calm. The animals administered high dose were died after a latent period (3 hours) and some of the animals in other groups were died within 24 hours. Concerning the haematological changes, there were no significant changes of PCV, Hb concentration, RBCs count, while there were significant increase of WBCs, and monocytes. Also there were highly significant increase and decrease of neutrophilis and lymphocytes respectively. The biochemical changes were reveled significant increase in creatinine, urea, uric acid, AST, ALP, cholesterol, T. protein and globulin. PM examination showed alveolar hemorrhages, proliferation of Kuppfer cells, necrosis infiltrated by lymphocytes in lung, liver and spleen. Hyaline deposits and pinkish staining proteineous deposits were seen in Bowman`s space of some glomeruli. It is concluded that E. heliscopia was a moderate toxic materials and must be avoided to introduce in the animal feed.
Kalman Filters versus Neural Networks in Battery State-of-Charge Estimation: A Comparative Study  [PDF]
Ala A. Hussein
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.35022
Abstract: Battery management systems (BMS) must estimate the state-of-charge (SOC) of the battery accurately to prolong its lifetime and ensure a reliable operation. Since batteries have a wide range of applications, the SOC estimation requirements and methods vary from an application to another. This paper compares two SOC estimation methods, namely extended Kalman filters (EKF) and artificial neural networks (ANN). EKF is a nonlinear optimal estimator that is used to estimate the inner state of a nonlinear dynamic system using a state-space model. On the other hand, ANN is a mathematical model that consists of interconnected artificial neurons inspired by biological neural networks and is used to predict the output of a dynamic system based on some historical data of that system. A pulse-discharge test was performed on a commercial lithium-ion (Li-ion) battery cell in order to collect data to evaluate those methods. Results are presented and compared.
Generation of Nanosecond Optical Pulses with Controlled Repetition Rate Using in-Cavity Intensity Modulated Brillouin Erbium Fiber Laser
Hussein Eissa Kotb;Mohamed Yehia Shalaby;Mahmoud Hanafi Ahmed
PIER , 2011, DOI: 10.2528/PIER10121901
Abstract: A multimode Brillouin Erbium Fiber Laser BEFL, at 1550 nm band, with in-cavity intensity modulation is demonstrated. The output of the laser is in the form of nanosecond pulses. The longitudinal mode separation is increased, which results in both reducing the number of oscillation modes and, at the same time, changing the output pulses repetition rate to be multiples of the round trip cavity frequency. It is also demonstrated that the number of modes is greatly reduced by the combination of active mode locking and the group velocity dispersion arising from the change in the refractive index at each mode due to the change in its gain within the Brillouin gain bandwidth. A case of a quasi single mode is reached where the output is nearly CW with very low sinusoidal modulation index.
Study on the Relationship between the Oceanic Nino Index and Surface Air Temperature and Precipitation Rate over the Kingdom of Saudi Arabia  [PDF]
Yehia Hafez
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.45015
Abstract: Abnormal weather conditions and extreme weather existed over the Kingdom Saudi Arabia (KSA) through the last decades. The present paper investigates the relationship between the Oceanic Nino Index (ONI) and variability of surface air temperature and precipitation rate over KSA through the period from 1950 to 2015 year. The NCEP/NCAR Reanalysis of monthly data sets of the mean surface air temperature and precipitation rate for the domain of the KSA is used. In addition, El Nino3.4 monthly data through the period (1950-2015) are used. For that period, the data set of the three months moving average of Nino3.4 anomaly, Oceanic Nino index (ONI), is used and analyzed. The time series, anomaly and correlation coefficient techniques are used to analyze the data sets through the present study. The results revealed that the KSA climate parameters, temperature and precipitation rates are controlled by ONI mainly in the autumn and winter seasons.
On the Relationship between Heat Waves over the Western and Central Europe and NAO, SOI, El-Nino 3.4 in Summer 2015  [PDF]
Yehia Hafez
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.54004
Abstract: An extreme warming hit Europe in summer of the year 2015. The present paper investigates the relationship between the North Atlantic Oscillation Index (NAO), Southern Oscillation Index (SOI) and El-Nino 3.4 and heat waves that persist over the western and central Europe in the summer of 2015. The NCEP/NCAR Reanalysis daily dataset of the mean surface air temperature for the domains of the western and central Europe for summer months (June, July and August) of the year, 2015 has used. In addition, the time cross-section analysis of the daily gridded operational data for the mean surface air temperature over the western and central Europe from 1 June to 31 August 2015 has done. Moreover, daily datasets of the NAO, SOI, and El-Nino 3.4 for that period have used. The time series, time cross section, anomaly and correlation coefficient techniques are used to analyze the data sets. The results revealed that the cases of heat waves that existed over the western and central Europe through the summer season of the year 2015 were controlled distinctly by the negative phase of the NAO and positive phase of ENSO.
A Recent Study of Seasonal and Interannual Climate Variability over the Eastern Mediterranean Region  [PDF]
Yehia Hafez
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.61009
Abstract: The present work aims to investigate seasonal and interannual climatic variability over the eastern Mediterranean (EM) region through the period (1949-2016). The monthly data of meteorological elements of temperature, pressure and precipitation for the EM region during the period (1949-2016) has used and analyzed. Moreover, the monthly NCEP/NCAR reanalysis data composites for these meteorological elements over the EM region have used. The seasonal and interannual variability of meteorological elements (surface air temperature, air temperature at 1000 hpa level, 500 hpa level, 500 hpa geopotential height, mean sea level pressure and precipitation) over the EM region during that period is studied. The anomaly, time series and correlation coefficient techniques, methods used for the data analysis. The results revealed that the climate variability of the EM region varied dramatically from season to season and from year to year through the period of study (1949-2016). There is a seasonal positive trend of temperature at 1000 hpa and 500 hpa levels and Geopotential height of 500 hpa level over the EM region. Meanwhile, it found a seasonal negative trend of mean sea level pressure and precipitation rate. For the interannual climatic variable over the EM region, it noticed that there was a positive trend of annual air temperature at the levels of 1000 hpa and 500 hpa. Meanwhile, there exists an annual negative trend anomaly of mean sea level pressure, 500 hpa geopotential height and precipitation rate over the EM region through the study period. It has become clear that the climate regime over the EM region is a complex regime.
Recent Study of Anomaly of Global Annual Geopotential Height and Global Warming  [PDF]
Yehia Yehia Hafez, Mansour Almazroui
Atmospheric and Climate Sciences (ACS) , 2014, DOI: 10.4236/acs.2014.43035
Abstract:

This paper studies the anomaly of global annual 500 hpa geopotential anomaly and global warming through the period (1950-2011). Anomaly method, linear trend and linear correlation coefficient techniques are referred to identify and describe the correlation between anomaly of global geopotential height field and global surface air temperature, North Atlantic Oscillation (NAO), Southern Oscillation Index (SOI), El-Nino3.4. The results revealed that, the anomaly of global annual geopotential height is completely controlled by global warming and NAO, SOI, El-Nino3.4 during the study period. However, the trend of the global surface air temperature anomaly completely coincides with the trend of 500 hpa geopotential height anomaly. This result uncovers the exist of abnormal weather phenomena through the last decades.

A Recent Study on the Relationship between Global Radiative Forcing and Global Annual Climatic Variability  [PDF]
Yehia Yehia Hafez, Mansour Almazroui
Atmospheric and Climate Sciences (ACS) , 2015, DOI: 10.4236/acs.2015.51003
Abstract:

The present paper investigates the relationship between the global radiative forcing (GRF) and global annual climatic variability. The relation between the GRF and global annual changes in the operational weather and climatic parameters is uncovered. There are several datasets which have been used to challenge this goal. The NCEP/NCAR Reanalysis dataset of several meteorological elements, such as air temperature, wind, surface pressure, outgoing long wave radiation, precipitation rate and geopotential height at level 500 hPa, etc. for the globe for the period (1948-2012), has been used. Furthermore, the GRF data for greenhouse gases through the period (1979-2010) has been used. Also, datasets of climatic indices NAO, SOI, El Nino 3.4 and SST during the period (1948-2012) have been used through this study. Time series analysis, anomaly and correlation coefficient technique methods have been used to analyze the datasets. The results reveal that there is an outstanding positive correlation coefficient (more than +0.80) between GRF and the global annual weather elements of surface air temperature, temperature and geopotential height at level 500 hPa, precipitation rate and sea surface temperature. CO2 has a significant correlation coefficient (+0.89) with the outcomes longwave radiation and sea surface temperature. There is a significant relationship between the global annual variability of weather and climatic elements and GHGs, global warming and climatic indices, NAO, SOI, El Nino 3.4 and SST.

The Effect of Incorporation of Ferrite Nano-particles on Compressive Strength and Re-sistivity of Self-Compacting Concrete  [PDF]
Mohamed A. Ahmed, Yehia A. Hassanean, Kamal A. Assaf, Moustafa A. Shawkey
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.51013
Abstract: Mn-Ferrite nanoparticles were prepared using citrate auto combustion method. The prepared sample was characterized by X-ray diffraction (XRD), HRTEM and BET to measure the particle diameter and the surface area of the prepared sample. The data of XRD clarified that the sample was formed in single phase spinel structure without any extra peaks indicating non-existence of any secondary phase. The HRTEM micrograph indicated that the particles were in an agglomerated state due to the absence of surfactant and high magnetic properties of Mn-Ferrite nanoparticles. The mechanical properties were measured at different ratios of nano-Ferrite to concrete. The obtained values of mercury intrusion porosimetry (MIP) indicated that the addition of Mn-Ferrite nanoparticles increased the compressive strength and decreased the total intrusion volume. This was due to the rapid consuming of Ca(OH)2 which was formed during hydration of Portland cement especially at early ages due to the high reactivity of MnFe2O4 nanoparticles. Moreover, MnFe2O4 nanoparticles recovered the particle packing density of the blended cement, leading to a reduced volume of pores in the cement paste.
Page 1 /462926
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.