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 .

        يأخذ هذا النوع من الدراسات أهميته في مجال الدراسات التاريخية لاسيما انه يقوم على أساس البحث والتقصي عن بعض الظواهر في المعاجم كونها  تمثل المصدر الأساسي الذي وجدنا فيه الجزء الأعظم من  تلك المادة المفقودة لكتاب النبات لابو حنيفة الدينوري.

Natural convection in a trapezoidal enclosure with partial heating from below and symmetrical cooling from the sides has been investigated numerically. The heating is simulated by a centrally located heat source on the bottom wall, and four different values of the dimensionless heat source length, 1/5, 2/5, 3/5, 4/5 are considered. The laminar flow field is analyzed numerically by solving the steady, two-dimensional incompressible Navier-Stokes and energy equations. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations  discretized by finite volume method; body fitted coordinates are used to represent the trapezoidal enclosure, and grid generatio

تناول البحث موضوعاً شديد الأهمية وهو الأمن الاجتماعي منظور اليه في سياق الحماية الجنائية لأمن الدولة والتحديات التي يتعرض لها بعد حصول تغيير حاسم في أساليب الحرب. كما يقدم البحث تقسيماً مختلفاً لأجيال الحروب نقتصر على اربعة منها استناداً إلى التغيير في أهداف الحرب الاستراتيجية وليس إلى مجرد وسائل ارتكابها لان هذه الوسائل لا تصلح لوصف التغييرات الحقيقية في أنماط الحروب والاهداف التي تسعى إلى تحقيقها. ويؤكد

The message of the Kurdish tag tagged with(Mada alfay fi taqrir lays  kamithlih shay) one of his most prominent scientific messages in the door of faith, especially in the matter of the unification of the divine self and its distancing from all analogies and representations  and the importance of this message historically, due to its documentation of a stage in the development of Islamic speech thought, where the logical method was taken over the minds of the intellectuals of Islam, including the kurani, whether it is in understanding the quranic and modern meaning or as a way of convincing me towards the opponent.

The Kurd was able to use logical concepts to marginalize the difference between grammarians and interprete

The energy consider generally and specifically the petroleum energy
from the prior requirement of the population and nations, and the basics of the
survival of mankind and all the challenges for the sake of continuum, so
without this energy the life of ankind being varied, so far the life is still as a
fact on the planet earth, and suppose the life may continue as the willing of
Allah ,that the events and the standards and the degree of development is still
as it is, in another word no any technical developments and no any
entertainment no transportation and also there is no demographic domination
for the whole lands belonging to Allah, certainly no way to talk more on what
we and the others knew, what is the g

In recent years, the means of communication have achieved a great generality that made them occupy, in a short time, the first ranks among the most widely used social networks in the world, due to the many services and advantages offered by this network to its users. It has led to a leap in the field of visual communication, especially since it relies mainly on the image Its dimensions make it a means of communication and transfer of ideas and meanings between the peoples of the world, and it also allows the inclusion of digital advertising content using multimedia with a degree of professionalism in other social networks, which allowed the various segments of society the opportunity to invest this network in their businesses of differen

      That art and poetic creativity is not associated with a certain time and place and that artistic inspiration is a gift from God loved to a group of individuals so that their experiences be simulated speaking to the insides of the human self and that the creativity of the artist poet lies in the purpose of what is familiar and accepted and mocked for this purpose to

Praise be to God, who is by His Power, righteous is done, and by His help to slaves who He likes, and God bless our Prophet Muhammad envoy mercy to the worlds, and upon his family and the good mates until Doomsday.After:

The fact that cursing is the far distance and expulsion from the mercy of God, curse has been proven by him - peace be upon him - for the many varieties in the Sunnah, with indication of a permit cursing the insurgents from the people of Qibla, either saying - peace be upon him -: (the believer never be as a curser  ...), what is meant by those who do not deserve damnation of those not cursed God and His Messenger, and for this we must remove words cursing from the Dictionary of our words following the examp