Dijkstra once wrote that computer science is no more about computers than astronomy is about telescopes. Despite the many incredible advances in c- puter science from times that predate practical mechanical computing, there is still a myriad of fundamental questions in understanding the interface between computers and the rest of the world. Why is it still hard to mechanize many tasks that seem to be fundamentally routine, even as we see ever-increasing - pacity for raw mechanical computing? The disciplined study of domain-speci?c languages (DSLs) is an emerging area in computer science, and is one which has the potential to revolutionize the ?eld, and bring us closer to answering this question. DSLs are formalisms that have four general characteristics. - They relate to a well-de?ned domain of discourse, be it controlling tra?c lights or space ships. - They have well-de?ned notation, such as the ones that exist for prescribing music, dance routines, or strategy in a football game. - The informal or intuitive meaning of the notation is clear. This can easily be overlooked, especially since intuitive meaning can be expressed by many di?erent notations that may be received very di?erently by users. - The formal meaning is clear and mechanizable, as is, hopefully, the case for the instructions we give to our bank or to a merchant online.

The production of phosphoric acid by sulfuric acid from high iron content phosphate rocks such as (Abu-Tartur phosphate rocks) has many disadvantages as low quality of produced acid and huge amounts of calcium sulfate. Also traditional process for production of dicalcium phosphate from wet phosphoric acid takes many steps. According to these problems, this work concerned to produce feed grade DCP by direct acidulation of Abu-Tartur phosphate rock with HCl in order to decrease production cost and produce relatively pure phosphoric acid. The leaching of phosphate ore by using dilute HCl was achieved in order to get maximum P2O5 leaching relative to minimum impurities. Kinetic analysis of the data indicates that the leaching process is ash layer diffusion controlled process. The production of DCP from direct acidulate phosphate rock was achieved by precipitating P2O5 by CaCO3. This process has many advantages over the conventional H2SO4 as: decrease production cost. In addition, the production of phosphoric acid from the produced DCP overcomes the traditional production problems and the produced phosphoric acid is more pure than the phosphoric acid produced directly by phosphate ore.

A translation from the Sudanese of Taha's major work in which he outlines the main features of his teachings. Mahmoud Mohamed Taha had long been known for his radical reinterpretation of Islam. His reputation, along with his vigorous opposition to the Islamization program, ultimately led to his demise