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Eatimation Availability Function Through Determination The Optimal Imperfect Preventive Maintenance Period By using Simulation
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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 as well as their respective efficiency extents, a mathematical model

is developed in order to study the evolution of the system stationary availability and determine the optimal PM period which maximizes

  1. The modeling of the imperfection of the corrective maintenance actions requires the knowledge of the quasi-renewal function when times to first failure follow a Weibull Distribution.

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Publication Date
Fri Nov 28 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Immunohistochemical evaluation of vascular endothelial growth factor and transforming growth factor-beta on osseointegration of CpTi implant radiated by low level laser therapy
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Background: Dental implants provide a unique treatment modality for the replacement of lost dentition .This is accomplished by the insertion of relatively inert material (a biomaterial) into the soft and hard tissue of the jaws, there by providing support and retention for dental prostheses. Low level laser therapy (LLLT) is an effective tool used to prompt bone repair and modeling post surgery; this has referred to the biostimulation effect of LLLT. The aims of this study were to evaluate the immmunohistochemical expression of vascular endothelial growth factor (VEGF) and transforming growth factor -beta (TGF-β) in experimental and control groups with mechanical test. Materials and Methods: Thirty two adult New Zealand white rabbits use

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Publication Date
Wed Jan 01 2003
Journal Name
Turkish Journal Of Chemistry
Gas Chr Gas Chromatographic Separ aphic Separation of Phenol Deriv ation of Phenol Derivatives by Schiff- y SchiffBase Liquid Crystalline Stationary Phases
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The chromatographic behaviour of liquid crystalline compounds benzylidene-p-aminobenzoic acid and 4-(p-methyl benzylidene)-p-aminobenzoic acid as stationary phases for the separation of dimethylphenol isomers was investigated. These isomers were analysed on benzylidene-p-aminobenzoic acid within a nematic range of 169-194 ◦C with a temperature interval of 5 ◦C. Better peak resolution was at a column temperature of 190 ◦C. The analysis was repeated on a 4-(p-methyl benzylidene)-p-aminobenzoic acid column at a nematic temperature of 256 ◦C, which represented the end of the nematic range, and gave the optimum peak resolution. It was found that isomer better separation was obtained at 20% loading for both liquid crystal materials. Other

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Publication Date
Fri May 01 2015
Journal Name
Journal Of Engineering
Numerical Analysis of Fluid Flow and Heat Transfer by Forced Convection in Channel with one-sided Semicircular Sections and Filled with Porous Media
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This research presents a numerical study to simulate the heat transfer by forced convection as a result of fluid flow inside channel’s with one-sided semicircular sections and fully filled with porous media. The study assumes that the fluid were Laminar , Steady , Incompressible and inlet Temperature was less than Isotherm temperature of a Semicircular sections .Finite difference techniques were used to present the governing equations (Momentum, Energy and Continuity). Elliptical Grid is Generated using Poisson’s equations . The Algebraic equations were solved numerically by using (LSOR (.This research studied the effect of changing the channel shapes on fluid flow and heat transfer  in two cases ,the first: cha

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Publication Date
Mon May 01 2017
Journal Name
The Journal Of Immunology
Attenuation of Staphylococcal enterotoxin-B (SEB)-induced lung injury (ALI) by resveratrol results from miR-193a down-regulation and alterations in metabolic profile
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Abstract<p>Resveratrol, (RES), a phytoalexin, is well-known for its anti-inflammatory and anti-oxidant properties. SEB, a superantigen, is known to trigger ALI and cause mortality. In the current study, we tested the effect of RES in a dual-dose model of SEB exposure that triggers ALI and causes 100% mortality in C3H/HeJ-mice. The data revealed RES attenuated SEB-induced ALI and prevented mortality. Forty eight hours post-SEB exposure, lung-infiltrating mononuclear cells were tested for microRNA expression profile to determine the epigenetic regulation by resveratrol. SEB-activated splenocytes were pre-treated with 50 μM of RES or vehicle for metabolic profile analysis by measuring oxygen consu</p> ... Show More
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Publication Date
Tue Dec 15 2020
Journal Name
Al-academy
Novel Coronavirus Pandemic as it is Expressed by Children in Their Drawings On-line: An Analytical Study: نزار بن صالح أحمد عبد الحفيظ
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This study aimed at identifying how children express the emerging coronavirus in general and according to their age groups (4-13 years) by analyzing 91 of their drawings published online, using the descriptive content analytical approach. The results showed that children's artistic expression of the virus came according to the concepts and ideas they carried about the virus for the age groups of (4-7 years) and (7-9 years), while it came according to visual perception for age groups (9-11 years), and from (11-13) years. Also, most children were aware about the presence of the virus and its widespread around the world, but (99%) of them do not realize the seriousness of the virus. It was confirmed that between (25-34%) of children were su

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Publication Date
Sun Jan 10 2021
Journal Name
Acta Medica Iranica
Early Stages Non-Traumatic Avascular Necrosis of Femoral Head Treated by Core Decompression With and Without Platelets Rich Plasma Injection: A Comparative Study
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Core decompression is one of the commonest used techniques in the handling of osteonecrosis of the pre-collapsed head of the femur. Core decompression had succeeded in preserving the hip joint and delaying the requisite for total hip replacement, but it had failed in the induction of osteogenesis in the necrotic area, thus augmenting core decompression with biological agents to induce osteogenic activity. To assess the effects of platelet-rich plasma in non-traumatic avascular necrosis of the hip joint (early stage) after core decompression. Interventional comparative study for twenty-four patients (32 hip joints) with AVN of the head of the femur was involved in this prospective study, and they were separated into two groups of 16

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Publication Date
Fri Dec 01 2023
Journal Name
Iop Conference Series: Earth And Environmental Science
Estimation of secondary compounds content of some citrus leaves and their relationship by dietary preference for yellow scale insect Aonidiella. Orientalis (Hemiptera: Diaspididae)
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Abstract<p>The yellow scale insect <italic>Aonidiella orientalis</italic> is an important pest of citrus trees as it absorbs sap from leaves and fruits, causing leaves to turn yellow and deform fruits and drop them. The results of study showed nutritional preference of the insect over some of studied citrus species, as sour orange was the most preferred, followed by lemon and grapefruit, mandarin and oranges were least preferred, with a rate of 22.3, 13.3, 11.7, 10.8, 3.9, and insect / 2 inch<sup>2</sup>, respectively. while results showed a difference in the content of citrus leaves from the secondary compounds, with highest concentration of phenols and total flavonoids in o</p> ... Show More
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Publication Date
Fri Jun 01 2012
Journal Name
Journal Of Engineering
Comparative Biosorption Of Pb(II), Cr(III) AND Cd(II) Ions In Single Component System By Live And Dead Anaerobic Biomass, Bath Study
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In this study, dead and live anaerobic biomass was used in biosorption of Pb(II), Cr(III) and Cd(II) ions from a synthetic wastewater. The biosorption was investigated by batch adsorption experiments. It was found that, the biosorption capacities were significantly affected by biosorbent dosage. The process follows Langmuir isotherm (regression coefficient 0.995, 0.99 and 0.987 for Pb(II), Cr(III) and Cd(II) ions, respectively, onto dead anaerobic biomass) model with uniform distribution over the biomass surface. The experimental uptake capacity was 51.56, 29.2 and 28 mg/g for Pb(II), Cr(III) and Cd(II), respectively, onto dead anaerobic biomass, compared with 35, 13.6 and 11.8 mg/g for Pb(II), Cr(III) and Cd(II), respectively, onto live

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Publication Date
Thu Feb 16 2023
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Qualitative and Quantitative Estimation or Chemical Constituents from Leaves and Roots of Iraqi Agave Attenuata by GC-MS and RP-HPLC(Conference Paper) #
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This research concentrate on cultivated Iraqi Agave attenuata dried leaves and roots, because of little studies on this plant especially on the root that lead to the eager of study and comparison of phytochemical constituents between leaves and root. Extraction of bioactive constituents was carried out using several solvents with increasing polarity (n-hexane, ethyl acetate and methanol) by soxhlet apparatus. Steroidal saponins in Agave genus is well documented in many species, lightening the minds in this research on extraction method which is specific for steroidal saponins. Phytochemical screening was done by GC/MS for n-hexane fraction, qualitative and quantitative estimation of several bioactive constituents (caffe

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Publication Date
Wed Jun 10 2020
Journal Name
Annals Of Tropical Medicine & Public Health
EFFECT OF EUCALYPTUS AND MYRTUS EXTRACTS IDENTIFICATION BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY ON SOME SPECIES OF CANDIDA AS A MODEL OF MEDICAL PLANTS
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The study showed that all extracts (aqueous, ethanolic and acetonic) of the leaves of Eucalyptus and Myrtus plants had a inhibitory effect on the growth of all types of yeasts studied, acetone extract recorded the highest inhibition of yeastat 100ppm concentration,The inhibition was 35mm, 34mm, 24mm and 20mm for Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida albicans respectively, The experiments above showed the least significant differences at 0.05 level.The results ofE. Cammldulensis ethanolic tincture analysis has shown the presence of 44 biologically active substances. The main Eucalyptus leaves component was: 2-Bicyclo (2-2.1) heptanol (12.37%), Ledol (8.23%),1,2,4- Benzenetriol (8.45%) and that contain spathul

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