This paper deals with the modeling of a preventive maintenance strategy applied to a single-unit system subject to random failures.

According to this policy, the system is subjected to imperfect periodic preventive maintenance restoring it to ‘as good as new’ with probability

p and leaving it at state ‘as bad as old’ with probability q. Imperfect repairs are performed following failures occurring between consecutive

preventive maintenance actions, i.e the times between failures follow a decreasing quasi-renewal process with parameter a. Considering the

average durations of the preventive and corrective maintenance actions a

Th   r:ats for the photo induced eleytr-on tra;nsfer reactions in the

Methylen-e blue 'l'vffi+ ·dye· with benzo_phenone (ABP) ketone in variety

solvc;:nts al n:loin tempemtme ha;ve qn calculated . Electron trans_ fer

-rates are large in• }stt:on;gly--'{:'lolaf- solvent and week in-l s.s :polar solvent.

the high values o:E   t±te r.tes a_f electro-n  tr;ans-fer indicate that tite dye

triplet i$ mqre, r activ.e toWard ABP ket-one.

     Magnetized iron oxide nanoparticles (NPs) were prepared using Eucalyptus leaf extract and then coated with CTAB (Cetrimonium bromide) to increase efficiency. The prepared and modified (NPs) were characterized using AFM, FTIR, and X-ray techniques. The adsorption of the dye reactive blue RB 238 on coated (NPs) was investigated. The effect of various experimental factors, such as the initial concentration of the dye, the amount of adsorbent, pH and temperature on the removal of RB238 was studied. The best conditions for dye removal were found to be 298 K in an acidic medium of pH = 3 and an appropriate dose of the adsorbent of 0.15 g per 25 mg/L to achieve the best color removal of 90% within 60 minutes. The pseudo-second-order re

This paper aims to propose a hybrid approach of two powerful methods, namely the differential transform and finite difference methods, to obtain the solution of the coupled Whitham-Broer-Kaup-Like equations which arises in shallow-water wave theory. The capability of the method to such problems is verified by taking different parameters and initial conditions. The numerical simulations are depicted in 2D and 3D graphs. It is shown that the used approach returns accurate solutions for this type of problems in comparison with the analytic ones.

To avoid the negative effects due to inflexibility of the domestic production inresponse to the increase in government consumption expenditure leads to more  imports to meet the increase in domestic demand resulting from the increase in government consumption expenditure. Since the Iraqi economy economy yield unilateral depends on oil revenues to finance spending, and the fact government consumer spending is a progressive high flexibility the increase in overall revenues, while being a regressive flexibility is very low in the event of reduced public revenues, and therefore lead to a deficit in the current account position. And that caused the deficit for imbalance are the disruption of the

Objectives: Maxillofacial silicone is used to restore abnormalities due to congenital or acquired causes. However, the quality of silicone is far from ideal. This study was aimed at assessing the influence of the addition of cellulose nanofibers (CNFs; several nanometers wide and 2-5 micro m long) on the physical and mechanical characteristics of maxillofacial silicone elastomers. Methods: Two CNF weight percentages (0.5% and 1%) were tested, and 180 specimens were divided into one control and two experimental groups. Each group was subdivided into six subgroups. In each subgroup, ten specimens subjected to each of the following tests: tearing strength, Shore-A hardness, tensile strength, elongation percentage, surface roughness, and color

The ceramic compound Mg1-xSixAl2O4 (x= 0, 0.1, 0.2, 0.3, 0.4) was prepared from nano powder of Al2O3 and MgO doped with Nano powder of SiO2 at different molar ratios. The specimens were prepared by standard chemical solid reaction technique and sintered at 1450 oC. Structure of the specimens was analyzed by using X-ray diffraction (XRD). The X-ray patterns of the specimens showed the formation of pure simple cubic spinel structure MgAl2O4 phase with space group of ̅ . The average grain size and surface topology were studied by atomic force microscopy. The results showed that the average grain size was about 73-90 nm. The DC electrical properties of the specimen were measured. The apparent density was found to increase and the porosity a