Subjects -> ASTRONOMY (Total: 94 journals)
Showing 1 - 46 of 46 Journals sorted alphabetically
Advances in Astronomy     Open Access   (Followers: 51)
Annual Review of Astronomy and Astrophysics     Full-text available via subscription   (Followers: 39)
Annual Review of Earth and Planetary Sciences     Full-text available via subscription   (Followers: 63)
Artificial Satellites     Open Access   (Followers: 23)
Astrobiology     Hybrid Journal   (Followers: 14)
Astronomical & Astrophysical Transactions: The Journal of the Eurasian Astronomical Society     Hybrid Journal   (Followers: 6)
Astronomical Journal     Full-text available via subscription   (Followers: 8)
Astronomical Review     Open Access   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 4)
Astronomy & Geophysics     Hybrid Journal   (Followers: 48)
Astronomy and Astrophysics     Full-text available via subscription   (Followers: 60)
Astronomy and Astrophysics     Open Access   (Followers: 32)
Astronomy and Computing     Hybrid Journal   (Followers: 2)
Astronomy Letters     Hybrid Journal   (Followers: 22)
Astronomy Reports     Hybrid Journal   (Followers: 15)
Astronomy Studies Development     Open Access   (Followers: 12)
Astroparticle Physics     Hybrid Journal   (Followers: 8)
Astrophysical Bulletin     Hybrid Journal   (Followers: 3)
Astrophysical Journal     Full-text available via subscription   (Followers: 19)
Astrophysical Journal Letters     Full-text available via subscription   (Followers: 14)
Astrophysical Journal Supplement Series     Full-text available via subscription   (Followers: 14)
Astrophysics     Hybrid Journal   (Followers: 29)
Astrophysics and Space Science     Hybrid Journal   (Followers: 46)
Astrophysics and Space Sciences Transactions (ASTRA)     Open Access   (Followers: 56)
Astropolitics: The International Journal of Space Politics & Policy     Hybrid Journal   (Followers: 12)
Celestial Mechanics and Dynamical Astronomy     Hybrid Journal   (Followers: 11)
Chinese Astronomy and Astrophysics     Full-text available via subscription   (Followers: 24)
Colloid Journal     Hybrid Journal   (Followers: 3)
Comptes Rendus Physique     Full-text available via subscription   (Followers: 2)
Computational Astrophysics and Cosmology     Open Access   (Followers: 3)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 11)
Earth, Moon, and Planets     Hybrid Journal   (Followers: 55)
Earth, Planets and Space     Open Access   (Followers: 74)
EAS Publications Series     Full-text available via subscription   (Followers: 8)
EPL Europhysics Letters     Partially Free   (Followers: 8)
Experimental Astronomy     Hybrid Journal   (Followers: 39)
Expert Opinion on Astronomy and Astrophysics     Open Access   (Followers: 7)
Extreme Life, Biospeology & Astrobiology - International Journal of the Bioflux Society     Full-text available via subscription   (Followers: 6)
Few-Body Systems     Hybrid Journal   (Followers: 1)
Foundations of Physics     Hybrid Journal   (Followers: 41)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 12)
Galaxies     Open Access   (Followers: 6)
Globe, The     Full-text available via subscription   (Followers: 4)
Gravitation and Cosmology     Hybrid Journal   (Followers: 4)
Icarus     Hybrid Journal   (Followers: 75)
International Journal of Advanced Astronomy     Open Access   (Followers: 28)
International Journal of Astrobiology     Hybrid Journal   (Followers: 4)
International Journal of Astronomy     Open Access   (Followers: 19)
International Journal of Astronomy and Astrophysics     Open Access   (Followers: 29)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 13)
International Letters of Chemistry, Physics and Astronomy     Open Access   (Followers: 12)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
Journal for the History of Astronomy     Full-text available via subscription   (Followers: 19)
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Astronomical Instrumentation     Open Access   (Followers: 3)
Journal of Astronomical Telescopes, Instruments, and Systems     Hybrid Journal   (Followers: 5)
Journal of Astrophysics     Open Access   (Followers: 26)
Journal of Astrophysics and Astronomy     Open Access   (Followers: 52)
Journal of Atmospheric and Solar-Terrestrial Physics     Hybrid Journal   (Followers: 199)
Journal of Cosmology and Astroparticle Physics     Hybrid Journal   (Followers: 38)
Journal of Geophysical Research : Planets     Full-text available via subscription   (Followers: 179)
Journal of Geophysical Research : Space Physics     Full-text available via subscription   (Followers: 178)
Journal of High Energy Astrophysics     Full-text available via subscription   (Followers: 22)
Kinematics and Physics of Celestial Bodies     Hybrid Journal   (Followers: 10)
KronoScope     Hybrid Journal   (Followers: 1)
Macalester Journal of Physics and Astronomy     Open Access   (Followers: 4)
MNASSA : Monthly Notes of the Astronomical Society of South Africa     Full-text available via subscription   (Followers: 1)
Molecular Astrophysics     Full-text available via subscription   (Followers: 1)
Monthly Notices of the Royal Astronomical Society     Hybrid Journal   (Followers: 14)
Monthly Notices of the Royal Astronomical Society : Letters     Hybrid Journal  
Nature Astronomy     Hybrid Journal   (Followers: 8)
New Astronomy     Hybrid Journal   (Followers: 27)
New Astronomy Reviews     Full-text available via subscription   (Followers: 17)
Nonlinear Dynamics     Hybrid Journal   (Followers: 19)
NRIAG Journal of Astronomy and Geophysics     Open Access   (Followers: 5)
Open Astronomy     Open Access   (Followers: 2)
Physics of the Dark Universe     Open Access   (Followers: 4)
Planetary and Space Science     Hybrid Journal   (Followers: 101)
Planetary Science     Open Access   (Followers: 52)
Proceedings of the International Astronomical Union     Full-text available via subscription   (Followers: 2)
Publications of the Astronomical Society of Australia     Hybrid Journal   (Followers: 2)
Publications of the Astronomical Society of Japan     Hybrid Journal   (Followers: 3)
Publications of the Astronomical Society of the Pacific     Full-text available via subscription   (Followers: 4)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 17)
Research in Astronomy and Astrophysics     Full-text available via subscription   (Followers: 29)
Revista Mexicana de Astronomía y Astrofísica     Open Access   (Followers: 2)
Science China Physics, Mechanics & Astronomy     Hybrid Journal   (Followers: 4)
Solar Physics     Hybrid Journal   (Followers: 34)
Solar System Research     Hybrid Journal   (Followers: 14)
Space Science International     Open Access   (Followers: 192)
Space Science Reviews     Hybrid Journal   (Followers: 97)
Space Weather     Full-text available via subscription   (Followers: 24)
Transport and Aerospace Engineering     Open Access   (Followers: 13)
Universe     Open Access   (Followers: 5)
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NRIAG Journal of Astronomy and Geophysics
Number of Followers: 5  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2090-9977
Published by Elsevier Homepage  [3203 journals]
  • Investigation of structural and electrical properties of ZnO varistor
           samples doped with different additives

    • Abstract: Publication date: Available online 4 July 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): M.M. Saadeldin, Osama A. Desouky, Makram Ibrahim, G.E. Khalil, M.Y. HelaliAbstractThree samples of ZnO doped with CuO as additive were prepared by solid state reaction from the calcined oxides and characterized by SEM, EDX, and AFM. The results revealed the presence of intergranular phase. Additives found to be between ZnO grains. The conductivity of the three samples was measured with the frequency up to 100 KHz by LCR circuit. The calculated coefficients of nonlinearity and the conductivity are shown to be highly dependent on the frequency, concentration of copper oxide, surface morphology, and microstructure of the varistor samples. The temperature dependence of the conductivity of these samples will be studied in the future work.
       
  • The photometric and geometric analysis of galaxy pair KPG 578

    • Abstract: Publication date: Available online 3 July 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): Y.H.M. Hendy, Gamal B. AliAbstractWe have presented BVR surface photometry and geometric analyses for galaxy pair KPG 578 a, b (NGC 7537, NGC 7541). The contour maps, BVR surface brightness profiles (SB) and geometric profiles (xc, yc, PA and Ellip = 1 − b/a) have been used for each galaxy in the pair. The galaxy pair KPG 578 is an intermediate pair with projected separation rp=35.4h70-1kpcand relative velocityΔv=15km/s. The total orbital mass of KPG 578 is determined to be Mt=6.03x109M⊙. While the total luminosity and the total orbital mass to the total luminosity of KPG 578 are found to be Lt=4.49x1010L⊙ and Mt/Lt=0.13M⊙/L⊙ respectively.While it has been believed that the galaxy pair KPG 578 is non-interacting system, in this work we have found that the galaxy pair KPG 578 has signs of interaction. The KPG 578a contains one short curved tidal tail in north-east. The KPG 578b has two curved tidal tails: the first is long in west and the second is short in east. The geometrical parameters of tidal tails (length (lt), thickness (ht) and area (At)) have been presented in this study.
       
  • Modeling sun’s radiation effect on restricted four bodies

    • Abstract: Publication date: Available online 29 June 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): M.N. Ismail, Sahar H. Younis, Fatma M. ElmalkyAbstractIn this work, a dynamical system of four bodies is constructed. The forces which govern the motion are mutual gravitational attractions of the primaries, and radiation pressure force emitted from the more massive body. The equations of motion for the four bodies have taken into account the radiation pressure. We have deduced that these equations can be solved by Laplace transformations; the eigenvalues are obtained to study the motion about the libration points which are taken from the classical method, then the stability around the libration points is studied. The results obtained are presented. We remark that this model has special importance in astrodynamics to send spacecraft to stable regions to move in gravitational fields for some planetary system.
       
  • Assessment of groundwater prospect and aquifer protective capacity using
           resistivity method in Olabisi Onabanjo University campus, Ago-Iwoye,
           Southwestern Nigeria

    • Abstract: Publication date: Available online 14 June 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): Olateju O. Bayewu, Moroof O. Oloruntola, Ganiyu O. Mosuro, Temitope A. Laniyan, Stephen O. Ariyo, Julius O. FatobaAbstractElectrical resistivity investigation was carried out at Olabisi Onabanjo University campus, Ago-Iwoye, Southwestern Nigeria with the aim of evaluating groundwater potential and aquifer protective capacity of the overburden units in the area. The underlain rocks are predominantly porphyroblastic and banded gneiss, quartz-schist and biotite-hornblende granite.Twenty-Four Vertical Electrical Sounding (VES) were probed using Schlumberger array with maximum current electrode spacing (AB/2) of 100 m at each point using the OHMEGA Allied resistivity meter. The data were interpreted using the partial curve matching and computer iteration programme using WINRESIST. Parameters such as overburden thickness, basement resistivity, reflection coefficient and longitudinal conductance were calculated and used for evaluating the groundwater potential and aquifer vulnerability of the study area.The predominant VES curve types obtained are KH, H, A, AKH, HKH and HA. The geoelectric sections show that the area is underlain by 3–5 layers: the topsoil (72.4–1735.6 Ω m), clay/clayey sand/sand/laterite (18.9–1349.5 Ω m), fractured basement (430.7–1021.4 Ω m) and the fresh basement (433.3–7146.4 Ω m). The plotted isopach map showed an overburden thickness range of 4.9–28.2 m with values greater than 20 m at the south-eastern and south-western parts of area. The reflection coefficient range is between 0.62 and 0.98 while protective capacity range is between 0.03 and 0.28. Groundwater potential of the area were classified as high (overburden thickness > 13 m and reflection coefficient  13 m and reflection coefficient ≥ 0.8); and low (overburden thickness  0.8). The protective capacity rating falls between poor to moderate, thus, vulnerable to infiltration of leachate and other surface contaminants.The study therefore helped in identifying favourable groundwater potential and the aquifer vulnerability of the area.
       
  • Structural study using 2D modeling of the potential field data and GIS
           technique in Sohag Governorate and its surroundings, Upper Egypt

    • Abstract: Publication date: Available online 7 June 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): Hosni H. Ghazala, Ismael M. Ibraheem, M Lamees, Menna HaggagAbstractThe main purpose of the present study is to identify the surface and subsurface structural features and configuration of the basement in the area around Sohag Governorate using Geographic Information System (GIS) and potential field data (gravity and aeromagnetic). The hill shade was found as the most suitable image for surface lineament delineation and to produce a fault potential prediction map using the overlay model technique. The subsurface faults and contacts were detected and traced out from the reduced to the pole (RTP) magnetic, Bouguer gravity anomaly, and tilt derivative maps. The basement structural map of study area has been created based on tilt derivative technique. The structural tectonic maps show that the E-W, NNW-SSE, and NNE-SSW directions are the main trends affecting the study area. The subsurface configuration of the basement was detected using two dimensional (2D) gravity and magnetic forward modeling along preselected six long profiles crossing the study area. The 2D models suggest a depth range to the basement of 400 to 4000 m.
       
  • Examination of soil effect upon GPR detectability of landmine with
           different orientations

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Shereen M. Ebrahim, N.I. Medhat, Khamis K. Mansour, A. GaberAbstractLandmines represent a serious environmental problem for several countries as it causes severe injured and many victims. In this paper, the response of GPR from different parameters of the landmine targets has been shown and the data is correlated with observed field experiment made in 2012 at Miami Crandon Park test site. The ability of GPR for detecting non-metallic mines with different orientations was revealed and soil effect upon the GPR signal was examined putting into consideration the soil parameters in different locations in Egypt such as in Sinai and El Alamein. The simulation results showed that PMN-2 landmine was detected at 5 cm and 15 cm depths, even at the minimum radar cross section vertical orientation. The B-Scan (2D GPR profiles) of PMN-2 target at 15 cm depth figured out high reflectivity for Wadi deposits due to large contrast between PMN-2 landmine material and soil of sand dunes.
       
  • Slope failures evaluation and landslides investigation using 2-D
           resistivity method

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): M.M. Nordiana, I.N. Azwin, M.N.M. Nawawi, A.E. KhalilAbstractSlope failure is a complex phenomenon that may caused to landslides. Buildings and infrastructure such as transportation facilities and pipelines located within the boundaries of a landslide can be damaged or destroyed. Slope failure classification and various factors contributing to the instability using 2-D resistivity survey conducted in Selangor, Malaysia are described. Six 2-D resistivity survey lines with 5 m minimum electrode spacing using Pole-dipole array were performed. The data were processed using Res2Dinv and surfer10 software to evaluate the subsurface characteristics. The 2-D resistivity results show that the subsurface consist of two main zones. The first zone was alluvium or highly weathered with resistivity value of 100–1000 Ω m and depth of>30 m. This zone consists of saturated area with resistivity value of 1–100 Ω m and boulders with resistivity value of 1200–7000 Ω m. The second zone with resistivity value of>7000 Ω m was interpreted as granitic bedrock. The study area was characterized by saturated zones, highly weathered zone, highly contain of sand and boulders that will trigger slope failure in the survey area. This will cause to low strength of soil, debris flow and movement of earth. On the basis of the case examples described, 2-D resistivity method is categorized into desirable and useful method in determination of slope failure and future assessments.
       
  • Thorium normalization as a hydrocarbon accumulation indicator for Lower
           Miocene rocks in Ras Ghara area, Gulf of Suez, Egypt

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): A.A. El-Khadragy, T.F. Shazly, I.M. AlAlfy, M. Ramadan, M.Z. El-SawyAbstractAn exploration method has been developed using surface and aerial gamma-ray spectral measurements in prospecting petroleum in stratigraphic and structural traps.The Gulf of Suez is an important region for studying hydrocarbon potentiality in Egypt. Thorium normalization technique was applied on the sandstone reservoirs in the region to determine the hydrocarbon potentialities zones using the three spectrometric radioactive gamma ray-logs (eU, eTh and K% logs). This method was applied on the recorded gamma-ray spectrometric logs for Rudeis and Kareem Formations in Ras Ghara oil Field, Gulf of Suez, Egypt.The conventional well logs (gamma-ray, resistivity, neutron, density and sonic logs) were analyzed to determine the net pay zones in the study area.The agreement ratios between the thorium normalization technique and the results of the well log analyses are high, so the application of thorium normalization technique can be used as a guide for hydrocarbon accumulation in the study reservoir rocks.
       
  • Time lapse (4D) and AVO analysis: A case study of Gullfaks field, Northern
           North Sea

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Emmanuel Bassey Umoren, Nyakno Jimmy GeorgeAbstractA 4D seismic or time lapse survey has been used to investigate the amplitude versus offset (AVO) effects on seismic data in order to identify anomalies in the Gullfaks field for three different reservoir intervals namely the Tarbert, Cook and Statfjord reservoirs. Repeatability analysis has shown that the earlier seismic vintages are the most unreliable for amplitude anomaly analysis as normalised root-mean square (NRMS) values are greater than 50%. This is above the threshold of good and medium repeatability. Fluid substitution models show increases in both P-wave velocity and density for increasing water saturations with a maximum change of 7.33% in the P-wave velocity, and this is in line with predictions from previous work using the Biot - Gassman equations. AVO modelling for the top Tarbert Formation interface produced scenarios of increasing amplitudes with offset for the presence of hydrocarbons, which dim out with 100% brine saturation. This correlates to class III gas sands for different situations of varying Poisson’s ratio across an interface, which has been previously modelled. Two anomalies were identified with one being related to increasing pressure due to water injection correlating to poor permeability around injector well 34/10-B-33. The second anomaly is a case of potential unswept hydrocarbons that displayed a consistent bright spot throughout all of the seismic vintages (in-inlines and crosslines). AVO attribute analysis of this event produced a class II anomaly. However, when comparing near and far offset seismic data, dimming effect was observed producing contrasting evidence. The dimming offset is viewed to have been as a result of poor repeatability values at far offsets. The modelling of the fluid contents in the studied formations to conform to existing literatures justifies the efficacy of the method.
       
  • Identification of channel geometries applying seismic attributes and
           spectral decomposition techniques, Temsah Field, Offshore East Nile Delta,
           Egypt

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Adel A.A. Othman, M. Fathy, Adel NegmAbstractThe Temsah field is located in eastern part of the Nile delta to seaward. The main reservoirs of the area are Middle Pliocene mainly consist from siliciclastic which associated with a close deep marine environment. The Distribution pattern of the reservoir facies is limited scale indicating fast lateral and vertical changes which are not easy to resolve by applying of conventional seismic attribute. The target of the present study is to create geophysical workflows to a better image of the channel sand distribution in the study area. We apply both Average Absolute Amplitude and Energy attribute which are indicated on the distribution of the sand bodies in the study area but filled to fully described the channel geometry. So another tool, which offers more detailed geometry description is needed. The spectral decomposition analysis method is an alternative technique focused on processing Discrete Fourier Transform which can provide better results. Spectral decomposition have been done over the upper channel shows that the frequency in the eastern part of the channel is the same frequency in places where the wells are drilled, which confirm the connection of both the eastern and western parts of the upper channel. Results suggest that application of the spectral decomposition method leads to reliable inferences. Hence, using the spectral decomposition method alone or along with other attributes has a positive impact on reserves growth and increased production where the reserve in the study area increases to 75bcf.
       
  • Assessment of tropospheric delay mapping function models in Egypt: Using
           PTD database model

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): M.A. Abdelfatah, Ashraf E. Mousa, Gamal S. El-FikyAbstractFor space geodetic measurements, estimates of tropospheric delays are highly correlated with site coordinates and receiver clock biases. Thus, it is important to use the most accurate models for the tropospheric delay to reduce errors in the estimates of the other parameters. Both the zenith delay value and mapping function should be assigned correctly to reduce such errors. Several mapping function models can treat the troposphere slant delay. The recent models were not evaluated for the Egyptian local climate conditions. An assessment of these models is needed to choose the most suitable one.The goal of this paper is to test the quality of global mapping function which provides high consistency with precise troposphere delay (PTD) mapping functions. The PTD model is derived from radiosonde data using ray tracing, which consider in this paper as true value.The PTD mapping functions were compared, with three recent total mapping functions model and another three separate dry and wet mapping function model. The results of the research indicate that models are very close up to zenith angle 80°. Saastamoinen and 1/cos z model are behind accuracy. Niell model is better than VMF model. The model of Black and Eisner is a good model. The results also indicate that the geometric range error has insignificant effect on slant delay and the fluctuation of azimuth anti-symmetric is about 1%.
       
  • Impact of Nasser Lake on gravity reduction and geoidal heights for Egypt

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Hussein A. Abd-Elmotaal, Atef Makhloof, Ayman Hassan, Mostafa AshryAbstractIn the course of the IAG African Geoid Project, it is needed to study the impact of the lakes on the gravity reduction and geoidal heights. The aim of this paper is to study the impact of the water in Nasser Lake on gravity reduction and geoidal heights for Egypt. The determination of the gravimetric geoid is based on the well-known remove-restore technique. The problem of the lakes occurs because the popular programs widely used in practice (e.g., TC-program (Forsberg, 1984)) assume that all positive elevations are filled with rock topography, and all negative elevations are filled with ocean water. This is, however, not true for the case of Nasser Lake, which lies completely above sea level, at about 180 m elevation, with a water depth of about 20 m. The paper presents an approach on estimating the impact of Nasser Lake on gravity reduction and geoidal heights using TC-program with some tricky cases. The results show that the impact of Nasser Lake on both gravity anomalies and geoid undulation is limited to the area of the lake. The impact of Nasser Lake on the gravity anomalies is in the order of sub mgal, while the impact of Nasser lake on the geoid undulation is significant and reaches few centimeters.
       
  • Solar flare induced cosmic noise absorption

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Olugbenga Ogunmodimu, Farideh Honary, Neil Rogers, E.O Falayi, O.S BolajiAbstractSolar flare events are a major observing emphasis for space weather because they affect the ionosphere and can eject high-energy particles that can adversely affect Earth's technologies. In this study we model 38.2 MHz cosmic noise absorption (CNA) by utilising measurements from the Imaging Riometer for Ionospheric Studies (IRIS) at Kilpisjärvi, Finland obtained during solar cycle 23 (1996–2009). We utilised X-ray archive for the same period from the Geostationary Operational Environmental Satellite (GOES) to study solar flare induced cosmic noise absorption. We identified the threshold of flare (M4 class) that could bear significant influence on CNA. Through epoch analysis, we show the magnitude of absorption that each class of flare could produce. Using the parameters of flare and absorption we present a model that could provide the basis for nowcast of CNA induced by M and X-class solar flares.
       
  • Preparation and characterization of silver nanoparticles homogenous thin
           films

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Maroof A. Hegazy, E. BorhamAbstractThe wet chemical method by metal salt reduction has been widely used to synthesize nanoparticles. Accordingly the silver nitrate used as silver precursor and sodium borohydrate as reduction agent. The silver nanoparticles were characterized by different characterization techniques including UV–VIS spectrometry, Transmission electron microscope (TEM), and Zeta potential technique. Thin films of the colloidal solution were fabricated using direct precipitation technique on ITO glass, silicon substrate and commercial glass substrate and characterized by imaging technique. The absorption peak of the silver nanoparticles colloidal solution was around 400 nm. The TEM images indicate that the silver nanoparticles had spherical shape and their sizes were from 10 to 17 nm. The particle size of the silver nanoparticles was confirmed by Zeta potential technique. The imaging technique indicated that the homogeneous distribution of the colloidal silver solution thin film on the silicon substrate was stronger than the ITO glass and inhomogeneous film was emerged on the commercial glass.
       
  • Investigation the Arithmetical or Tabular Islamic calendar

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): M.G. Rashed, M.G. Moklof, Alaa E. HamzaAbstractArithmetical calendar (or tabular calendar) is sometimes referred to as the Fātimid calendar but this is in fact one of several almost identical tabular Islamic calendars. This calendar introduced by Muslim astronomers in the 9th century CE to predict the approximate begin of the months in the Islamic lunar calendar. Chronologists adopted 11 leap years in a 30 year cycle. In the case of leap Hijri year they add one day to the last month of the Hijri year. The cycle of this calendar agree with the Smaller cycles (2–5.333 years) discovered by Galal and Rashed (2011) and coincide with the lag criterion given by Galal (1988).We suggested the Islamic tabular calendar. The Leap years of this suggested Islamic tabular calendar may be 2, 5, 7, 10, 13, 15, 18, 21, 23, 26 and 29. Our suggested Arithmetical calendar satisfies the mathematical patterns, while the old Arithmetical calendar (or tabular calendar) does not satisfy a known fixed rule.We conclude empirical formula for our suggested Islamic tabular calendar. From this empirical formula, we can calculate if the Hijric year after immigration is a leap or a non-leap year.
       
  • Forecasting the peak of the present solar activity cycle 24

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): R.H. Hamid, B.A. MarzoukAbstractSolar forecasting of the level of sun Activity is very important subject for all space programs. Most predictions are based on the physical conditions prevailing at or before the solar cycle minimum preceding the maximum in question. Our aim is to predict the maximum peak of cycle 24 using precursor techniques in particular those using spotless event, geomagnetic aamin. index and solar flux F10.7. Also prediction of exact date of the maximum (Tr) is taken in consideration. A study of variation over previous spotless event for cycles 7–23 and that for even cycles (8–22) are carried out for the prediction. Linear correlation between maximum of solar cycles (RM) and spotless event around the preceding minimum gives R24t = 88.4 with rise time Tr = 4.6 years. For the even cycles R24E = 77.9 with rise time Tr = 4.5 y’s. Based on the average aamin. index for cycles (12–23), we estimate the expected amplitude for cycle 24 to be Raamin = 99.4 and 98.1 with time rise of Traamin = 4.04 & 4.3 years for both the total and even cycles in consecutive. The application of the data of solar flux F10.7 which cover only cycles (19–23) was taken in consideration and gives predicted maximum amplitude R24 10.7 = 126 with rise time Tr107 = 3.7 years, which are over estimation. Our result indicating to somewhat weaker of cycle 24 as compared to cycles 21–23.
       
  • Unusual ionospheric variations before the strong Auckland Islands, New
           Zealand earthquake of 30th September, 2007

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): J.I. Ibanga, A.E. Akpan, N.J. George, A.M. Ekanem, A.M. GeorgeAbstractUsing the IAP experiment on board, the DEMETER and TEC from GPS data, unusual ionospheric variations have been observed some days before the 7.4 magnitude New Zealand earthquake. Both sets of data recorded perturbations 10 days before the earthquake at about the same time. The total ion density per centimeter cube (cm−3), recorded a variation of 6.94 while the differential total electron content (DTEC) in total electron content unit 1016 electron per metre square gave a value of 2.93TECU. The observed anomalies were screened for false alarm using the geomagnetic indices of Kernnifzer digit (Kp) and disturbance storm time (Dst.) It was however seen that the state of the ionosphere was geomagnetically quiet during this period; hence the observed variations were seismogenic.
       
  • BVR photometric investigation of galaxy pair KPG 562

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Y.H.M. HendyAbstractThis work presents BVR photometric observations and analyses for galaxy pair KPG 562 selected from the Karachentsev Catalog of Isolated Pairs of Galaxies. The observations were obtained using the 1.88-m Telescope of the Kottamia Astronomical Observatory (KAO), Egypt. There is no interaction signs assigned for this pair as reported by Karachentsev Catalog.We used the surface photometry technique to obtain photometric parameters for each galaxy of the pair. The isophotal contours, the luminosity profiles, color profiles (B-V, V-R), ellipticity profiles, position angle (PA) profiles and isophotal center-shift (xc, yc) profiles have been presented. The total and absolute magnitude, ellipticity and position angle (PA) were also obtained from the studied galaxy pair.The studied galaxy pair is clearly showing signs of interaction opposed to that found by Karachentsev. We found that the galaxy KPG 562b contains one tidal tail. The length and thickness of tidal tail were obtained and presented in this study.
       
  • Probing Schrodinger equation with a continued fraction potential

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Nasr Ahmed, Sultan Z. Alamri, M. RassemAbstractWe suggest a new perturbed form of the quantum potential and investigate the possible solutions of Schrodinger equation. The new form can be written as a finite or infinite continued fraction. a comparison has been given between the continued fractional potential and the non-perturbed potential. We suggest the validity of this continued fractional quantum form in some quantum systems. As the order of the continued fraction increases the difference between the perturbed and the ordinary potentials decreases. The physically acceptable solutions critically depend on the values of the continued fraction coefficients αi.
       
  • Inside Front Cover

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s):
       
  • Implementation of magnetic and gravity methods to delineate the subsurface
           structural features of the basement complex in central Sinai area, Egypt

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Sultan Awad Sultan Araffa, Mohamed El-bohoty, M. Abou Heleika, Mahmoud Mekkawi, E. Ismail, Ahmed Khalil, Enas M. Abd EL-RazekAbstractThe area of study is situated in the center of Sinai Peninsula. The current study is concerned with the analysis of magnetic and gravity data aiming to evaluate the subsurface structure of the basement rocks. The aeromagnetic and gravity methods of prospecting give an effective presentation of the subsurface structures. The aeromagnetic data was corrected and represented by total aeromagnetic intensity map then was reduced to the north magnetic pole. The corrected gravity data is represented by Bouguer anomaly map. The filtering techniques were applied to the corrected aeromagnetic and gravity maps to obtain the residual component caused by local structures and anomalies bodies. The integration of radially power spectrum was applied on both magnetic and gravity to estimate the depths of the shallow sources and the deep sources. The equivalent depths of the isolated short wavelength anomalies are 0.5 km and 0.4 km, and the depths of the long wavelength anomalies are 3.5 and 3 km for the magnetic and gravity data, respectively. The Euler deconvolution and 3-D modeling were applied to magnetic and gravity data. The 3-D Euler deconvolution is used not only to delineate major subsurface structures but also to determine the structural indices of them as well as the average depth of the magnetic and gravity sources. The calculated structural indices show that the area is mainly affected by contacts/thin sheet and the estimated depth of magnetic and gravity sources ranged between 500 m and 2000 m, also the 3-D Euler deconvolution showed that the area was affected by different fault trends such as NNE-SSW, NW-SE and E-W trends. The results of 3-D magnetic and gravity interpretation revealed that the depth of basement was ranging from 2500 m to 3000 m .The main tectonic deformations of the area of study have NNE-SSW, NW-SE and E-W trends.
       
  • Application of Dempster-Shafer theory of evidence model to geoelectric and
           hydraulic parameters for groundwater potential zonation

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Kehinde Anthony Mogaji, Hwee San LimAbstractThe application of a GIS – based Dempster – Shafer data driven model named as evidential belief function EBF- methodology to groundwater potential conditioning factors (GPCFs) derived from geophysical and hydrogeological data sets for assessing groundwater potentiality was presented in this study. The proposed method’s efficacy in managing degree of uncertainty in spatial predictive models motivated this research. The method procedural approaches entail firstly, the database containing groundwater data records (bore wells location inventory, hydrogeological data record, etc.) and geophysical measurement data construction. From the database, different influencing groundwater occurrence factors, namely aquifer layer thickness, aquifer layer resistivity, overburden material resistivity, overburden material thickness, aquifer hydraulic conductivity and aquifer transmissivity were extracted and prepared. Further, the bore well location inventories were partitioned randomly into a ratio of 70% (19 wells) for model training and 30% (9 wells) for model testing. The synthesized of the GPCFs via applying the DS – EBF model algorithms produced the groundwater productivity potential index (GPPI) map which demarcated the area into low – medium, medium, medium – high and high potential zones. The analyzed percentage degree of uncertainty for the predicted lows potential zones classes and mediums/highs potential zones classes are>10% and
       
  • Empirical relationship between electrical resistivity and geotechnical
           parameters: A case study of Federal University of Technology campus, Akure
           SW, Nigeria

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): O.J. Akintorinwa, S.T. Oluwole
       
  • Texture analysis of aeromagnetic data for enhancing geologic features
           using co-occurrence matrices in Elallaqi area, South Eastern Desert of
           Egypt

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Ahmed M. Eldosouky, Sayed O. ElkhateebAbstractEnhancement of aeromagnetic data for qualitative purposes depends on the variations of texture and amplitude to outline various geologic features within the data. The texture of aeromagnetic data consists continuity of adjacent anomalies, size, and pattern. Variations in geology, or particularly rock magnetization, in a study area cause fluctuations in texture. In the present study, the anomalous features of Elallaqi area were extracted from aeromagnetic data. In order to delineate textures from the aeromagnetic data, the Red, Green, and Blue Co-occurrence Matrices (RGBCM) were applied to the reduced to the pole (RTP) grid of Elallaqi district in the South Eastern Desert of Egypt. The RGBCM are fashioned of sets of spatial analytical parameters that transform magnetic data into texture forms. Six texture features (parameters), i.e. Correlation, Contrast, Entropy, Homogeneity, Second Moment, and Variance, of RGB Co-occurrence Matrices (RGBCM) are used for analyzing the texture of the RTP grid in this study. These six RGBCM texture characteristics were mixed into a single image using principal component analysis. The calculated texture images present geologic characteristics and structures with much greater sidelong resolution than the original RTP grid. The estimated texture images enabled us to distinguish multiple geologic regions and structures within Elallaqi area including geologic terranes, lithologic boundaries, cracks, and faults. The faults of RGBCM maps were more represented than those of magnetic derivatives providing enhancement of the fine structures of Elallaqi area like the NE direction which scattered WNW metavolcanics and metasediments trending in the northwestern division of Elallaqi area.
       
  • Geophysical characterization of the role of fault and fracture systems for
           recharging groundwater aquifers from surface water of Lake Nasser

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Khamis Mansour, Khaled Omar, Kamal Ali, Mohamed Abdel ZaherAbstractThe role of the fracture system is important for enhancing the recharge or discharge of fluids in the subsurface reservoir. The Lake Nasser is consider one of the largest artificial lakes all over the world and contains huge bulk of storage water. In this study, the influence of fracture zones on subsurface fluid flow in groundwater reservoirs is investigated using geophysical techniques including seismicity, geoelectric and gravity data. These data have been utilized for exploring structural structure in south west Lake Nasser, and subsurface discontinuities (joints or faults) notwithstanding its related fracture systems. Seismicity investigation gave us the comprehension of the dynamic geological structure sets and proposing the main recharging paths for the Nubian aquifer from Lake Nasser surface water. Processing and modelling of aerogravity data show that the greater thickness of sedimentary cover (700 m) is located eastward and northward while basement outcrops occur at Umm Shaghir and Al Asr areas. Sixty-nine vertical electrical soundings (VES’s) were used to delineate the subsurface geoelectric layers along eight profiles that help to realize the subsurface geological structure behind the hydrogeological conditions of the studied area.
       
  • Delineation potential gold mineralization zones in a part of Central
           Eastern Desert, Egypt using Airborne Magnetic and Radiometric data

    • Abstract: Publication date: Available online 1 June 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): Sayed Omar Elkhateeb, Mahmoud Ali Gaballah AbdellatifAbstractLocalization of probable gold mineralization zones in a selected part of the central Eastern Desert of Egypt has been executed by mapping lithology, structures and hydrothermal alteration zones. In this regard, both aeromagnetic and aeroradiometric data have been utilized in the analysis; by making use of some enhancement techniques such as first vertical derivative, analytic signal and both Center for Exploration Targeting (CET) grid and porphyry. Also, ratio and ternary radiometric maps have been launched to aid in the interpretation process. The results indicated that the study area is dominant by NW, NNW, NNE, WNW, NE, E-W and N-S structural directions. The NW-SE was the most important one and considered as the preferred orientation of ore deposits. Favorable regions of ore deposits were mapped and correlated well with known gold occurrences in the study area beside predicting new zones of mineralization. Analysis of aeroradiometric maps facilitates the correlation and delineation of lithological units based on the concentration of radioelements and ratios. Also, A number of hydrothermal alteration zones were mapped within younger granite, Hammamat felsites and Metasediments. Finally, A composite map consists of geology, structures and hydrothermal altered zones was generated using ArcGIS. Eight known locations of gold mineralization were investigated on this map and also new sites were suggested to be favorable locations for mineralization emplacement.
       
  • Studying the variation of eddy diffusivity on the behavior of
           advection-diffusion equation

    • Abstract: Publication date: June 2018Source: NRIAG Journal of Astronomy and Geophysics, Volume 7, Issue 1Author(s): Khaled Sadek Mohamed Essa, Aziz Nazer Mina, Hany Saleh Hamdy, Fawzia Mubarak, Ayman Ali khalifaAbstractIn this work, the advection-diffusion equation was solved in two dimensions to calculate the normalized crosswind integrated concentration by Laplace technique. Considering that the wind speed is constant and we have two models of the vertical eddy diffusivity, one depends on downwind distance and the other model depends on vertical distance. A comparison between our proposed two models, Gaussian, previous work and observed data measured at Copenhagen, Denmark, have been carried out. One finds that there is a good agreement between predicted (2) model and the observed concentrations than predicted (1), Gaussian and previous work.From the statistical technique, one finds that all models are inside a factor of two with observed data. Regarding to Normalized mean square error (NMSE) and Fraction Bais (FB), proposed model (2) is performance well with observed data than the predicted (1), Gaussian and previous work in unstable condition.
       
  • Using RTK and VRS in direct geo-referencing of the UAV imagery

    • Abstract: Publication date: Available online 25 May 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): M. Rabah, M. Basiouny, E. Ghanem, A. ElhadaryAbstractDirect Geo-Referencing is a new technique in photogrammetry, especially in the aerial photogrammetry. Unlike the Aerial Triangulation “AT”, this method does not require Ground Control Points “GCPs”, to process aerial photographs into desired ground coordinates systems. Compared with the old method, this method has four main advantages: faster field work, faster data processing, simple workflow and less cost. Generally, direct geo-referencing using two systems, Global Navigational Satellite Systems “GNSS” and Inertial Navigational System “INS”. GNSS recording the camera coordinates “X, Y, Z”, and INS recording the camera orientation angles “w, φ, k” at the time of exposure. These parameters merged and are provided to each photograph in the processing stage.The current paper investigates the using GNSS system for providing the linear exterior orientation “EO” parameters “X, Y, Z” by two techniques, real time kinematic “RTK” and virtual reference system “VRS”. The accuracy of the applied method is tested on topographic survey project in Switzerland. The surveyed data of the specified project were collected by amateur digital camera Canon 18.2 MP, 182 captured images from approximately 85 m flight height, 18 Ground Check Point “GCP” determined by static GNSS. Horizontal accuracy is 0.029 m for VRS case, 0.034 m for RTK case and vertical accuracy is 0.026 m for VRS case, 0.029 for RTK case.
       
  • Development of model for predicting elastic parameters in ‘bright’
           field, Niger Delta using rock physics analysis

    • Abstract: Publication date: Available online 24 May 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): S.J. Abe, M.T. Olowokere, P.A. EnikanseluAbstractAccurate differentiation of reservoir fluid and determination of elastic parameters when some logs are not available is a major challenge in the petroleum industry and this study explored the potential of rock physics modeling to resolve these challenges. Suite of logs from four wells were provided, but only three wells were used for the analysis because well 3 does not have density log. Petrophysical properties were calculated from the logs using the respective equations and pseudo shear wave velocity was estimated from the P-wave velocity. The result of the rock physics analysis carried out using crossplots of acoustic impedance against P-wave velocity coloured with gamma ray log was able to separate the lithology into sand and shale both within the wells and the reservoirs of interest with the aid of the relevant rock physics models. Vp/Vs against acoustic impedance crossplots coloured with density log indicated the pore fluid in the wells and mapped sand bodies to be water and oil. Two mathematical models for predicting elastic parameters in the absence of some necessary logs were developed and these models can be used in the Niger Delta and in other sedimentary basins of the world.
       
  • Anomalous ultra low frequency signals possibly linked with seismic
           activities in Sumatra, Indonesia

    • Abstract: Publication date: Available online 8 May 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): E.M. Takla, A. Khashaba, M. Abdel Zaher, A. Yoshikawa, T. UozumiAbstractAnomalous Ultra Low Frequency signals observed by ground-based magnetometers that linked with seismic events are commonly accepted. These anomalous signals can be promising phenomena for constructing early Earthquake-warning systems. The present study analyzes high-resolution (1-s) geomagnetic data recorded at the Kototabang (KTB) station, Indonesia, and other remote reference stations to detect the occurrence of any anomalous ULF signals that may associated with a number of seismic events occurred in Sumatra, Indonesia. The amplitude of the ULF emissions in the Pc3 range (10–45 s) was examined during three big seismic events that occurred in Sumatra between 2004 and 2007. Results of data processing and analysis indicate the presence of anomalous enhancement in the Pc3 amplitude ratio (ZPc3/HPc3) at KTB station in association with the studied seismic events. On the other hand, there are no noticeable changes at other distant reference stations during the examined periods. In addition, there are no remarkable external geomagnetic disturbances during the studied seismic events as it reveals from the Disturbance storm time (Dst) index. So, we can conclude that the observed anomalous changes might be a possible signature related to the above-mentioned seismic events in Sumatra, Indonesia.
       
  • Application of geoelectrical measurements for detecting the ground-water
           seepage in clay quarry at Helwan, southeastern Cairo, Egypt

    • Abstract: Publication date: Available online 30 April 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): A.M.S. Abd El-Gawad, A.S. Helaly, M.S.E. Abd El-LatifAbstractClay is considered one of the most important raw materials in cement industry. It is the most common rich source of silica and alumina. During the quarrying process a few months later, a new feature of water accumulation appeared on the quarry floor and many water pools were formed during excavation process. In order to detect the source and extension of the ground-water seepage, geoelectrical resistivity technique in the form of vertical electrical soundings was applied. Fifteen vertical electrical soundings with AB/2 from 1 to 150 m have been executed.Geoelectrical resistivity measurements are applied in Helwan clay quarry to understand the source of the groundwater accumulated recently on the floor of quarry. The results indicate the passage of groundwater from the adjacent areas through channel ways formed as a result of the excavation process. All over the measured area, there are some sand lenses intercalated with clays & during the excavation process, some channels formed and the groundwater started to percolate through these channels forming many water pools along the quarry floor.
       
  • Gamma-ray spectrometric investigation of north El-Tor area, southwestern
           Sinai, Egypt

    • Abstract: Publication date: Available online 17 March 2018Source: NRIAG Journal of Astronomy and GeophysicsAuthor(s): Ibrahim M. Gaafar, Ahmed Abdrabboh, Abdalla S. AlshamiAbstractInterpretation was executed on the airborne and ground spectrometric data of Abu-Zeneima/Al-Tor area for verifying the significant anomalies as it contains important targets for prospective nuclear materials. Airborne spectrometric survey revealed that younger granites, are characterized by increase in the three main radioactive elements up to 5.4% K, 10 ppm eU and 33 ppm eTh. The western part of the study area includes sedimentary section which contains uranium-bearing phosphate beds. They are characterized by increase of airborne uranium concentration up to 14.2 ppm without potassium or thorium enrichment. The airborne image maps for eU/eTh and eU/K as well as ternary composite map revealed also that there is a promising U-anomaly, associated with the sedimentary section.Detailed ground spectrometric survey for the Cretaceous Nubian sandstone in Wadi Araba indicated that it is characterized by eU content reaches about 34 ppm, while eTh attains only about 9.8 ppm and potassium is 1.2%. Therefore, the eU/eTh ratio, reaches to a value of 3.4. The same sandstone bed in Abu - Durba Formation possesses eU values reach 67 ppm, whereas eTh values attain 38 ppm and average of potassium is 0.5%. The eU/eTh ratio is about 2, indicates also enrichment of uranium. The eU reaches a concentration of about 40 ppm in limestone of Matulla Formation whereas, the eTh values attains about 3 ppm and average K is 0.1%. Therefore, the eU/eTh ratio reached 13, due to the limestone is phosphatic. High eU value reaching to 80 ppm is recorded in the limestone facies of Sudr Formation, while the eTh values up to 11 ppm and potassium of about 0.9% are recorded. The eU/eTh ratio value reaching 7.3 indicates the high P2O5 content. A high uranium content is recorded at the northeastern part of El-Qaa plain area in the Sudr Formation reaching 47 ppm, while low eTh values attaining 7.5 ppm and potassium of 0.1% are recorded.
       
 
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