2024-03-29T15:57:59Z
https://absb.journals.ekb.eg/?_action=export&rf=summon&issue=6736
Al-Azhar Bulletin of Science
1110-2535
1110-2535
2019
30
Issue 1-B
SOME UNUSUAL GENERATING INTEGRALS INVOLVING HERMITE POLYNOMIALS
Ahmed
Youssef
In this paper we seek to find some bilateral generating functions for some orthogonal polynomials like Hermite, Charlier, Modified Laguerre and Gegenbaur polynomials. These bilateral generating functions can be obtained with the help of the unusual integral formula for Hermite polynomial seen in equation (1.1).
Hermite polynomials
Modified Laguerre
Gegenbaur polynomials
2019
06
01
1
8
https://absb.journals.ekb.eg/article_66074_2f047ec8115493b04d32fef3eda2b838.pdf
Al-Azhar Bulletin of Science
1110-2535
1110-2535
2019
30
Issue 1-B
VIBRATIONS CONTROL OF THE HARMONICALLY EXCITED NONLINEAR SYSTEM VIA POSITIVE POSITION FEEDBACK CONTROLLER
Y.
Amer
A.
EL-Sayed
A.
Saleh
A.
Abdel-Wahab
Hala
Salman
In this paper, the vibration reducing of the harmonically excited nonlinear system is presented via applying positive position feedback controller (PPF). The analytical results are obtained by applying the multiple-scale perturbation techniques (MSPT) up to second-order approximations. The frequency response equation (FRE) is studied to test the be havior of the steady state solutions near the simultaneous resonances. The effects of the several parameters and the behavior of the system at resonance case are investigated to illustrate the optimum
working conditions for the PPF controller. The stabilit y analysis for the uncontrolled system is investigated by applying the phase portrait technique. Moreover, numerical simulation is used to compare between time-history and the analytical solution. The analytical and numerical solutions are compared to show the validity of the results. Finally, a comparison with the available results in the literature is presented
Nonlinear system
Multiple scales method
Resonance
PPF controller
Stability, phase plane
2019
06
01
9
26
https://absb.journals.ekb.eg/article_42891_ad6edc598305feaf4f7266510aa5f044.pdf
Al-Azhar Bulletin of Science
1110-2535
1110-2535
2019
30
Issue 1-B
SEMANTIC NESTED SEARCH ENGINE VIA INTEGRATION ONTOLOGY WITH MULTI-AGENT SYSTEM
Eman
Elsayed
AbdAllah
ELHabashy
Raghda
khaled
Global and private search engines retrieve a huge amount of information within thousands of web pages. That is based on user’s search criteria. Nevertheless, it is a challenge to analyze all the information retrieved to match her/his required information. Solving this challenge needs to combine information retrieval systems (IR) with text mining and artificial intelligent approaches. This paper proposes enhanced search engines to be semantic nested search which can be used in business domain. This is via integrating Ontology, Multi-agent technology, and human computer interaction (HCI) concepts. Where Ontology provides a semantic view for understanding the pages contents then Multi-agent collects synchronously the selected information from each link. The proposed semantic nested search engine (SNS) have three phases and use four agents. The SNS engine will be applied on three case studies; jobs search, ecommerce products search and the scientific conferences search. We use different accuracy measurement such as relevant results, recall, precision and F-score. Also, we compare the proposed SNS engine with Google, Yahoo and Bing general search engines. The proposed system consume time. But the run time is not bad relative to the manual searching time inside the links, i.e. overall, the proposed SNS saves users’ time and effort.
Multi-Agent
ontology
Human Computer Interaction (HCI)
Information Retrieve (IR)
2019
06
01
27
36
https://absb.journals.ekb.eg/article_66075_8d11352d9c8556d574504bbd09662529.pdf
Al-Azhar Bulletin of Science
1110-2535
1110-2535
2019
30
Issue 1-B
NATURAL RADIOACTIVITY ASSESSMENT AND THE ASSOCIATED RADIOLOGICAL HAZARDS FOR BEACH SAND, BALTIM AREA, EGYPT.
Hany
Shousha
M.
Atta
A.
Bakhit
H.
Diab
A.
El Hagg
Samah
Dahy
Natural radioactivity of 238U, 232Th series and 40K of black sand samples collected along El-Fanar and El-Nargess Beaches in Baltim area, north of the Nile Delta in Kafr El-Sheikh Governorate, were measured using a gamma-ray spectrometer with a high purity germanium (HPGe) detector. Results showed that the average activity concentrations of 238U and 232Th in El-Fanar Beach was significantly higher (73.22±5.1 and 70.8 ± 4.9 Bq kg-1) than El-Nargess Beach (31.91±2.2 and 25.95 ±1.8 Bq kg-1) respectively. The average activity concentrations of 40K in El-Fanar Beach was lower (67.47±4.7 Bq kg-1) than that in El-Nargess Beach (80.75±5.6 Bq kg-1). The hazard indices due to these radionuclides have been calculated. The obtained results from this study indicate that the average activity concentrations of 238U, 232Th and40K at El-Nargess Beach are within world median ranges while average activities of 238U and232Th in El-Fanar Beach are higher than the world mean (33and45) Bq kg-1 respectively. This study aimed to establish a baseline map of radioactivity background levels in the aforementioned region to assess any change in the radiological background levels due to any artificial effects attributed to any radiation activities.
Natural radioactivity
radionuclides
radiation hazard, Baltim Area
Egypt
beach sand samples
2019
06
03
37
47
https://absb.journals.ekb.eg/article_67879_c03660354330e6026559362f335827b5.pdf
Al-Azhar Bulletin of Science
1110-2535
1110-2535
2019
30
Issue 1-B
CHARACTERIZATION OF 241AM-BE NEUTRON SOURCE USING THRESHOLD FOIL ACTIVATION TECHNIQUE
N.
Kotb
M.
Tohamy
A.
Solieman
T.
El - Zakla
T.
Amer
S.
Elmeniawi
M.
Comsan
The aim of the study is to characterize 241Am-Be isotopic neutron source with 5 Ci activity and nominal neutron yield 1.1×107 n/s. The emitted neutrons were measured employing threshold multi-foil activation technique using the following reactions: 115In(n,n'), 58Ni(n,p), 64Zn(n,p), 27Al(n,p), 56Fe(n,p), 59Co(n,α), 24Mg(n,p), and27Al(n,α). The threshold reactions were selected based on their half-lives, adequate threshold energy and cross-section. The reaction rate of each sample foil is measured by detecting the gamma ray spectra produced as a result of reaction products decay. A hyper pure germanium detector (HPGe) is used for gamma-ray spectrum measurements. The obtained spectra were analyzed using Genie2000 software and the associated system absolute efficiency was calculated using Efftran software. Obtained reaction rates were compared with available published data.
241Am-Be neutrons
HPGe
threshold reactions
activation technique
reaction rate
2019
06
01
48
53
https://absb.journals.ekb.eg/article_67880_a3b96e5c92dd7b13ab5b19ac8acbb0fb.pdf
Al-Azhar Bulletin of Science
1110-2535
1110-2535
2019
30
Issue 1-B
PERTURBED GROUND TRACK UNDER THE INFLUENCE OF J2 AND LUNISOLAR FORCES
M.
Awad
I.
Hassan
H.
Dewdar
A.
Saad
A several types of forces are acting on the satellite. These forces are classified into conservative and nonconservativeforce. The main concern in the present research work is to studding the effect of conservative forces on the satellite orbital motion and represent this effect on satellite ground track. Where the ground tracks are the locus of points formed by the points on the Earth directly below a satellite as it travels in orbit. A mathematical model and a program code is designed using Matlab package to calculate the perturbed ground track under J2 and luni-solar forces. Whereas the J2 and Luni-Solar are a conservative forces, the secular variation is presented only in RAAN and . Otherwise the remaining orbital element is varies periodically. The perturbed ground track is calculated under the effect of J2 and luni-solar forces. The perturbed position vectors for a satellite are converted to its corresponding latitudes and longitudes. The satellite’s position in one revolution is displayed to represent where the satellite at the time desired.
Satellite
oblateness
earth’s gravitational force
luni-Solar force
ground Track
2019
06
01
54
61
https://absb.journals.ekb.eg/article_66072_d6d1b3f3e2f9e98bb39b3bcca7ca5519.pdf