The main target of this paper is to determine the optimum time for preventive maintenance on machines. Tow methods has been implemented estimating the optimum time duration for preventive maintenance . the first techniques use scheduling depending on data concerning the machine maintenance cost and halted cost from the production reach to the optimum time for maintenance which reflect the minimum cost. Where as the second techniques depends on reability function to estimate the optimum duration time which reflect the minimum cost. The tow techniques above by which we count on in fixing the preventive maintenance both give same result . we also prove that the scheduling method best than the reability function .

In the past, an absolute authority was held by the father and his decisions were imposed
and obeyed strictly without discussion. Later, many economical changes took place and
affected all of the family members dramatically creating a whole new concept of authority
in the family, a one that is based upon sound leadership, mutual understanding and
consultation among family members.
Women carried responsibility of doing all domestic jobs and served family members,
however, when she went to work outside her house, these loads began disturbing and
exhausting her. Therefore, man started to participate in assisting his wife. In addition,
industrial advances contributed in making these jobs easier than before.
This has

Footnotes are considered as an important phenomenon in the lectures of grammar. Al-Khudari's footnote is one of the most distinguished one other than its counterparts due to the prestigious and scientific status of its author

     الحمد لله رب العالمين، والصلاة والسلام على سيد المرسلين، محمد وعلى آله وصحبه أجمعين وبعد:

فإن الله تعالى خلقنا أزواجا، وجعل منا الذكر والأنثى يميل بعضهم إلى بعض بالفطرة والطبع ليكونا بمشيئة الله أسرة، ويرزقان بنين وحفدة، وهذه سنة الله تعالى في الخلق لا يزيغ عنها إلا هالك.

ومن نعم الله تعالى على بني البشر أن جعل النكاح المشروع لا السفاح الممنوع أساس العلاقة بين ال

دور المواد النانوية في إعادة تصنيف تكاليف المنتج الصناعي الحديث

This research investigates modern linguistics in terms of the “universality” concept, through which linguistics shifted its attention from the description of the phenomenon into finding an interpretation of it. Then it investigates what needs interpretation in the language

This research investigates modern linguistics in terms of the “universality” concept, through which linguistics shifted its attention from the description of the phenomenon into finding an interpretation of it. Then it investigates what needs interpretation in the language