A Visa Story from Palestine

Palestinians are subject to special difficulties when applying for a visa: the ban imposed by the Israeli military authorities on Palestinians entering Israel and traveling via Bin Gurion airport is compounded by the obligation of Palestinians who need to travel abroad to fly via Queen Alia International Airport in Amman. Since September 11th the author and many of his colleagues have experienced overwhelming difficulties in securing visas to travel abroad to attend the smallest activity. Harsh and restrictive visa policies are playing into the hands of extremists on both sides. It is the responsibility of colleagues in countries that are implementing these restrictions to pressure their governments to change those policies.     

Ancient Mining and Smelting Activities in the Wadi Abu Gerida Area,Central Eastern Desert,Egypt: Preliminary Results

Old mining and smelting features in the Abu Gerida area have been studied using field observations, microscopy and SEM–EDS to detect the ores that were exploited in antiquity. There are two groups of shafts in the area. The first group encloses secondary copper minerals and is associated with glassy slags containing copper prills. The other group is associated with hematite that was extracted and transferred to a smelting station to the west of the mining site, where iron slags and charcoal fragments are found. These slags are composed mainly of wüstite, fayalite–kirschsteinite and traces of metallic iron. Pottery fragments from this area were dated to the Ptolemaic Period, which may be the age of iron exploitation. Copper might have been exploited earlier.     

Evaluation of recoverable energy potential from enhanced geothermal systems: a sensitivity analysis in a poro‐thermo‐elastic framework

This study presents application of an efficient approach to simulate fluid flow and heat transfer in naturally fractured geothermal reservoirs. Fluid flow is simulated by combining single continuum and discrete fracture approaches. The local thermal nonequilibrium approach is used to simulate heat transfer by conduction in the rock matrix and convection (including conduction) in the fluid. Fluid flow and heat transfer models are integrated within a coupled poro‐thermo‐elastic framework. The developed model is used to evaluate the long‐term response of a geothermal reservoir with specific boundary conditions and injection/production schedule. A comparative study and a sensitivity analysis are carried out to evaluate the capability of the integrated approach and understand the degree by which different reservoir parameters affect thermal depletion of Soultz geothermal reservoir, respectively. Also observed, there exists an optimum fracture permeability after which the reservoir stimulation does not change the recovery factor significantly. Estimation of fluid temperature by the assumption of local thermal nonequilibrium heat transfer between the fracture fluid and the rock matrix gives fluid temperature of about 3°C less than that of estimated by thermal equilibrium heat transfer at early stage of hot water production.