Natural and anthropogenic influences in the northeastern coast of the Nile delta,Egypt

Landsat enhanced thematic mapper imagery (ETM) of 2002 and aerial photography of 1955, combined with published charts and field observations were used to interpret coastal changes in the zone between Kitchener drain and Damietta spit in the northeastern Nile delta, previously recognized as a vulnerable zone to the effects of any sea level rise resulting from global warming. The interpretation resulted in recognition of several changes in nine identified geomorphological land types: beach and coastal flat, coastal dunes, agricultural deltaic land, sabkhas, fish farms, Manzala lagoon, saltpans, marshes and urban centers. Reclamation of vast areas of the coastal dunes and of Manzala lagoon added about 420 km2 to the agricultural deltaic land. About 48 km2 of backshore flats, marshes, salt pans and Manzala lagoon have been converted to productive fish farms. The main urban centers have expanded; nearly 12.1 km² have been added to their areas, and new urban centers (Damietta harbor and the New Damietta city) with total area reach of ~35.3 km² have been constructed at the expense of vast areas of Manzala lagoon, coastal dunes, and backshore flats. As a consequence of human activities, the size of Manzala lagoon has been reduced to more than 65%. Shoreline changes have been determined from beach profile survey (1990–2000), and comparison of 1955 aerial photographs and ETM satellite image of 2002 reveal alongshore patterns of erosion versus accretion. The short-term rate of shoreline retreat (1990–2000) has increased in the downdrift side of Damietta harbor (≃14 m/year), whereas areas of accretion exist within the embayment of Gamasa and in the shadow of Ras El Bar detached breakwaters system, with a maximum shoreline advance of ~15 m/year. A sandy spit, 12 km long, has developed southeast of Damietta promontory. These erosion/accretion patterns denote the natural processes of wave-induced longshore currents and sediment transport, in addition, the impact of man-made coastal protection structures.     

Distribution and Influence of Iron Phases on the Physico—Chemical Properties of Phyllosilicates

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD,DTA,dissolution analysis(DCB),IR,Moessbauer and X-band Electron Spin Resonance(ESR) spectroscopies.The purity of the samples and the degree of structural order were determined by XRD.The location of Fe in the octahedral sheet is characterized by absorption bands at-875cm^-1 assigned as Al-OH-Fe which is present after chemical dissolution of free iron.The Moessbauer spectra of these clays sow two doublets with isomer shift and quadrupole splitting typical of octahedral coordinated Fe^3 ,in addition to third doubler with hyperfine parameter typical of Fe^2 in the spectra of Abu-Had kaolinite (H)sample.6-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples.Goethite was confirmed by both IR and DTA.Multiple nature of ESR of these clays suggested structural Fe in distorted octaedral symmetry and as non-structural Fe.Little dispersion and low swelling indices as well as incomplete activaiton of investigated montmorillonite samples by NaCO3 appear to be due to incomplete disaggregation of montmorillonite particles.This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure.However,extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples.On the other hand,amounts and site occupation of Fe associated with kaolinite samples show a negative correlation with the parameters used to describe the degree of crystalline perfection,color,brightness and vitrification range of these kaolinite samples.     

Long-term behaviour of three well-known flare stars of the UV Ceti type

Long-term changes in two flare stars, EV Lac and BY Dra, have been detected by Mavridiset al. (1982). These long cyclic periods have been registered in theB-band at their quiescent-state luminosity as well as at their flare activity. Those observational data of the two previously mentioned flare stars as well as another observational data of the flare star, UV Cet, at its flare activity were submitted to our computer programme for periodicity detection excluding cyclic periods which have amplitudes less than tenth magnitude for great significance. Some of our results coincided with the long cyclic periods detected by Mavridiset al. (1982) while the remainder of our results have had no complete coincidence with those registered by Mavridiset al. (1982).     

A possible continuum theory for densification and liquefaction of saturated sand

A previously developed continuum theory of granular media is applied to the problems of densification and liquefaction of saturated sand. An expression for the free energy of saturated sand is developed. The process of densification of sand subjected to cyclic shear stress is studied and several expressions for an increase of the solid volume fraction are obtained and discussed. The problem of the initial liquefaction of saturated sand samples under cyclic shear stress is then considered and several criteria relating the shear stress amplitude, over-burden pressure, time to liquefaction, and physical properties of the sand sample are established. Some semiempirical relations for field applications are also presented.     

Nature and human impact on Nile Delta coastal sand dunes,Egypt

This paper deals with the types, distribution and origin, of recent sand dunes in the coastal sector extending between El Burullus Lake and the Damietta Nile River branch, Egypt. Sand samples were studied for grain size distribution and mineralogical composition. It has been found that most of the dunes in the study area have been subjected to deterioration and removal due to the construction of summer resort buildings and making the international coastal highway. The remnant constitutes a belt of foredunes on the shore of Baltium extending westward to Burg El Burullus village.The dunes origin is interpreted as the result of coastal drifting and the subsequent transport of the former Sebennitic Nile branch sediments eastward by the predominant longshore current and by Aeolian processes. The blown sand grains accumulated to form a belt of coastal sand dunes with longitudinal and crescentic forms. Urbanization of the coast has severely altered the landscape. Gaps and damaged dunes are included within the dune belt. The dunes natural cycle of advance and retreat is upset and attains its destruction phase. The consequences of its destruction are numerous and lead to hazardous impacts on the shoreline, coastal building and the nearby international highway.     

Mental health preparedness for natural disasters in Iran

Appropriate emergency preparedness and response rely on social, economical, cultural, and political infrastructures, which vary widely according to the level of the development of each country. Mental health damages are among the consequences of absence of such infrastructure, which have not been studied comprehensively till to date. In most countries, planning for natural disasters and earthquakes has been mainly focused on physical and economical impacts; however, lessons learnt from recent earthquakes in Iran and other countries show that psychological impacts need to be considered more seriously. The first responder to an emergency is really the affected community, which consequently should be mentally prepared by appropriate training programs. These should include simple psychosocial interventions developed for people with average level of education in a way to be easily understandable and practicable. After the Bam earthquake, local community volunteers have been selected and trained to provide post-disaster mental health services.