In this work, HgBa2CaCu2-xSbxO8+δ compounds with (x = 0.2, 0.4, 0.6 and 0.8) have been prepared by the solid-state reaction method. Structural, morphological, and electrical properties were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Using the 4-probe technique to study the effect of antimony-substitution for Copper on the electrical properties of HgBa2CaCu2-xSbxO8+δ (Hg-1212) phase was investigated by measuring the resistivity as a function of temperature. Results indicate that the addition of antimony (Sb) increases the volume fraction of the phase and changes the superconducting transition temperature Tc of the superconductor to a normal state. The dielectric loss factor and ac conductivity have been investigated at room temperature. It was found that dielectric properties decreased with increasing electric field frequency. It was observed that the best value was 0.8 of the Sb content. Generally, with increasing antimony content, at lower frequencies, higher dielectric criteria are achieved, while at higher frequencies, lower dielectric criteria are achieved. On the other hand, the dissipation of the energy in the dielectric is directly proportional to the dielectric loss factor. Considering this, the increase in the values of ac conductivity is increasing with an increased frequency range to 5 MHz.
Background: This study was performed to determine the effect of aging of different types of composite material restorations on: Shear bond strength (SBS) to light cure and no mix chemical cure orthodontic adhesives with sapphire bracket and the debonding failure sites. Materials and methods: One hundred forty four composite disks were made from three different composite resin materials which are: 3M Filtek Z250, 3M filtek Z350 and 3M Valux plus, each group with (48) disks each, then according to the duration of storage each group was subdivided into two equal groups one of them stored for one day and the other was stored for one month, then each group was further subdivided into two equal subgroups with (12) disks each one bonded with ligh
... Show MoreBackground: Decalcification of surface enamel adjacent to fixed orthodontic appliances, in the form of white spot lesions, is a wide spread and familiar well-known side effect of orthodontic treatment. The present study was carried out to evaluate the effect of enamel protective agent (Clinpro white varnish) on shear and tensile bond strength of Dentaurum orthodontic stainless steel brackets by using 3M Unitek and Ormco as orthodontic adhesive agents. Materials and methods: Sixty-four extracted human upper first premolar teeth were selected and randomly divided into two groups with 32 teeth each, representing the shear and tensile bond strength testing groups. Then according to the type of bonding adhesive and the addition of Clinpro before
... Show MoreThe current research aims to identify the effect of the learning mastery strategy using interactive learning as a therapeutic method on the achievement of secondary school students in mathematics. To achieve the research objective, the researcher selected second-grade middle school students at Al-Haybah Intermediate School for Boys and determined his research sample, which consisted of (77) students distributed into two sections: Section (A) the experimental group, with (38) students, and Section (B) the control group, with (39) students. The statistical equivalence of the two research sample groups was confirmed in the variables (intelligence test, previous achievement, and previous knowledge test). The researchers chose the par
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Polycyclicacetal was prepared from the reaction of PEG with aldehyde derived from Erythro-ascorbic acid (pentulosono-ɣ-lactone-2,3-enedianisoate).All these compounds were characterized by Thin Layer Chromatography (TLC) and FTIR spectra and aldehyde was also characterized by (U.V-Vis), 1HNMR, 13CNMR, and mass spectra.The inhibitory effect of prepared polymer on the activity of human serum AcetylCholinesterase has been studied in vitro. The polymer showed a remarkable activity at low concentration (4.7x10-3 – 4.7x10-8M).
This study was carried out at the Poultry Research Station belong to state Board of Agricultural Research, Ministry of Agriculture, Abu Ghraib. The duration of this study was from 28 November 2013 to 15 May 2014 to evaluate the effect of supplementation different levels of organic selenium(Se-yeast) and inorganic selenium (Selenium selenite) on some productive performances of broiler breeder and selenium levels in plasma ,egg (yolk,albumin). The study included 336 female broiler breeder and 28 males (Ross 308 and arbor acres), 42 weeks old were randomly distributed to 7 dietary treatments experiment with 2 replicates / treatment (24 females and 2 male birds /replicate). The duration of the experiment was 24 weeks, and treatments were as the
... Show MoreBackground: A recent discoveries used for reconstruction in maxillofacial surgery is the composite bone graft materials. The availability of collagen I matrix make our choice to use this material in surgery .It is biomaterials that its structure could be modified by simple techniques. Studies to find a new materials use for bone reconstruction is to overcome the disadvantages of autogenous bone and the synthetic resorbable bone substitutes.
Objectives: This study was done to evaluate the effect of biphasic calcium phosphate collagen composite (ccpc) on healing of bone defects after oral surgical procedures.
Type of the study: A cross sectional study.
Method: It involved 60 patients, 35 male and 25 female, age (15-
... Show MoreManagement Representations Letter plays a significant role as an evidence to get conclusions the Auditor is looking for. These conclusions could show the professional opinion of auditor over the fairness and integrity of financial statements for many issues and numbers that management claims, Hereby, the research aims at highlighting the importance of Management Representations Letter and the way of using as an evidence with expressing its meaning and means of application in addition to identify the Responsibility of Auditor on that Letter, This research discusses also the effect of Management Representations Letter on the credibility of financial statement and enhancing the credibility of the submitted reports, From other side, in the t
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