Gamma radiation measurements of naturally occurring radioactive samples from commercial Egyptian granites

Due to the widespread use of granites as building and ornamental materials, measurements of natural radioactivity for a total 27 selected samples of commercial granites used in Egypt were carried out by using a high pure germanium detector. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K of commercial granites ranged from 25 to 356, 5 to 161, and 100 to 1,796?(Bq?kg^?1), respectively. The concentrations of these radionuclides are compared with the international recommended values. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the absorbed dose rate, the effective dose rate, and the hazard index have been calculated. The radium equivalent activity Ra_eq varied from 41 to 669?(Bq?kg^?1) which exceeds the permitted value (370?Bq?kg^?1) and the internal hazard index H _in varied from 0.2 to 2.8 which is higher than 1. The absorbed dose rate due to the natural radioactivity in the samples under investigation ranged from 19 to 310?(nGy?h^?1). The total effective dose rates per person indoors were determined to be 0.09 to 1.5?(mSv?year^?1).     

Application of ASTER and Landsat TM Data for Geological Mapping of Esfandagheh Ophiolite Complex,Southern Iran

This research developed an approach to enable the discrimination of lithological units and detection of host rock of chromitite bodies within ophiolitic complexes using the advanced spaceborne thermal emission and reflection radiometer (ASTER) and Landsat thematic mapper (TM) satellite data. Three main ophiolite complexes located in southern Iran were selected for the study. A specialized band ratio (4/1, 4/5, 4/7) of ASTER, minimum noise fraction (MNF) components and spectral angle mapper (SAM) on ASTER and Landsat TM data were used to distinguish ophiolitic rock units. Results show that the specialized band ratio was able to identify different rock units and serpentinized dunite as host rock of chromitites within ophiolitic complexes. Minimum noise fraction components of ASTER and Landsat TM data are suitable for distinguishing ophiolitic rock complexes at a regional scale. The integration of SAM and feature level fusion used in this investigation discriminated the ophiolitic rock units and provided geological map for the study area, including identification of high potential areas (serpentinite dunite) for chromite exploration targets.     

Geochemistry and mineral chemistry of Pan-African amphibolites of South Sinai,Egypt

In the Wadi Feiran area, amphibolites occur as inclusions, bands, linear bodies of variable thickness and irregular lenses in para-geneisses. Chemical evidence indicates that these amphibolites display an igneous origin and were derived from magma essentially of tholelitic rather than alkaline composition; transitional in character between continental and island-arc. The chemistry of amphiboles, related to pressure and temperature conditions of meta-morphism, showed that they were formed under low pressure and high temperature conditions.     

A survey of temporal and spatial reference crop evapotranspiration trends in Iran from 1960 to 2005

Reference crop evapotranspiration (ET₀) is one of the most important climatic parameters which plays a key role in estimating crop water demand and scheduling irrigation. Under global warming and climate change conditions, it is needed to survey the trend of ET₀ in Iran. In this study, ET₀ values were determined based on FAO-56 Penman-Monteith equation over 32 synoptic meteorological stations during 1960–2005; and analyzed spatially and temporally in monthly, seasonal and annual time scales. After removing the significant lag-1 serial correlation effect by pre-whitening, non-parametric statistical Mann–Kendall (MK) test was used to detect the trends. The slope of the changes was determined by Sen’s slope estimator. In order to facilitate in trend analysis, the 10 moving average low pass filter were also applied on the normalized annual ET₀ time series. Annual ET₀ time series and filtered ones were then classified by hierarchical clustering in three clusters and then mapped in order to show the patterns of different clusters. Results showed that the significant decreasing trends were more considerable than increasing ones. Among surveyed stations, and on an annual time scale, the highest and lowest annual values of Sen’s slope estimator were observed in Tabas with (+) 72.14 mm per decade and Shahrud with (?) 62.22 mm per decade, respectively. Results also indicated that the clustered map based on normalized and filtered annual ET₀ time series is in accordance with another map which showed spatial distribution of increasing, decreasing and non-significant trends of ET₀ on annually time scale. Exploratory and visual analysis of smoothed time series showed increasing trend in recent years especially after 1980 and 1995. In brief, the upward trend of ET₀ in recent years is a crucial issue with regard to the high cost of dam construction for agricultural aims in arid and semi-arid regions e.g. Iran.     

Minimum, maximum, and mean annual temperatures, relative humidity, and precipitation trends in arid and semi-arid regions of Iran

One of the most important scientific concerns of the last few decades is climate change, which is the result of a great many factors like global warming. Although a number of studies have been dedicated to understand the phenomenon of climate change, more attention is required to understand the potential effects of global warming on the ecosystems as well as on human life. The present study was designed to survey the trends of minimum, maximum and mean temperatures, relative humidity, and the time series of annual precipitation and 10-year moving average low-pass filter in the 13 synoptic weather stations of Iran’s arid and semi-arid regions during the last 55 years by using τ Kendall test. The analyses indicate a significantly increasing trend for the minimum and mean temperatures while a decreasing trend for the mean relative humidity in the arid and semi-arid regions, especially during the last few years up to the year 2000. Any clear increasing or decreasing trend was not found for the maximum temperature, while the precipitation did not show any increasing/decreasing trend for most of the surveyed stations. Further studies, with long-term programming, are recommended to be carried out to evaluate the climate change and its effects on such regions.     

Shock waves and the chemical structure of interstellar clouds

In this paper we study the effect of shock waves on the chemical structure of the interstellar clouds. A model of molecular cloud has been assumed. The chemistry is investigated in a time dependent model. Our chemical network contains 56 species in 251 reactions to including molecules of the elements H, O, C, N, S, and Si.The results indicate that the calculated fractional abundance of the molecules NS, H₂O, CN, NH, CO, and SO agrees well with the observations. The molecules OH, H₂S, CS, H₂CS, HS, NO, SiO, CH, CH₂, CH₃, HCO, C₂, and HCN reach high post-shock abundances.     

Experiments on uni-directional and nonlinear wave group shoaling

Ocean Dynamics - We report an experimental study addressing the characteristic hydrodynamic transformations of unstable wave groups as well as JONSWAP wave fields propagating from deep-water...     

Effect of the spectral shape of ground motion records on the collapse fragility assessment of degrading SDOF systems

The main purpose of this paper is to study the collapse capacity of single degree of freedom(SDOF) systems and to produce fragility curves as well as collapse capacity spectra while considering a broad range of structural parameters, including system degradation, the P-Δ effect, ductility capacity and the post-capping stiffness ratio. The modified IbarraKrawinkler deterioration model was used to consider hysteretic behavior. A comprehensive study was conducted to extract the collapse capacity spectrum of SDOF systems with a wide range of periods, varying from 0.05 to 4 s, to cover short, intermediate and long periods. Incremental dynamic analysis(IDA) was performed for SDOF systems to identify the condition in which the collapse capacity of the system is determined. The IDAs were performed using different sets of seismic ground motions. The ground motion records were categorized into different sets based on three spectral shape parameters, including the epsilon, Sa Ratio and N_p. The collapse fragility curves of SDOF systems with different periods were extracted to illustrate the collapse capacity at different probability levels. The results show that structural degradation and ductility as well as the spectral shape parameters significantly affect the collapse capacity of SDOF systems. On the other hand, the post-capping stiffness ratio and small levels of the P-Δ effect do not remarkably change collapse capacity. Also, the collapse capacity of SDOF systems is more sensitive to the records categorized based on Sa Ratio and N_p than those classified based on epsilon.     

An ActiveX control for embedding GPS capability in custom applications

An ActiveX GPS control is presented which can be used to develop software applications with GPS functionality. It translates the NMEA 0183 interface GPS instructions and triggers event procedures which are used by applications to access the GPS data. It provides position data in the form of geographic coordinates as well as Universal Transverse Mercator (UTM) projected coordinates. This control is recommended for the development of general purpose GPS-enabled applications which do not require a high level of accuracy. A Visual Basic project is also included to demonstrate the use of various features of this control. Finally, some real-time software applications are discussed which have been developed using this control. These applications include static point averaging; path tracking; and imagery-based position mapping.     

Effects of Land Transformation on Water Quality of Dal Lake,Srinagar, India

The present study focuses on the growing human needs which drive the native boatmen of the Kashmir valley (Hanjis) that bring the interchanges of land use/cover classes in Dal lake and its environs of Srinagar city. Further to assesses the effects of land transformation on lake water quality. The results suggested that the significant land use changes have been occurred during the past of 30 years (1981–2011). Besides this, interchange of land has taken place between different land uses classes, which has resulted into lake water pollution due the addition of various nutrients/pollutant discharged from Hanjis activities. The study concludes that the land transformation has converted the once fresh water lake much deteriorated pond.