ABSTRACT Background:Hydrogen absorption and related degradation in the mechanical properties of Ni-Ti based orthodontic wires has been demonstrated following exposure to fluoride prophylactic agents. This study was designed to investigate the effects of three fluoride containing agents on the load deflection characteristics of heat activated nickel titanium arch wires during unloading phase. Material and method: Eighty specimens of heat activated nickel titanium arch wires were obtained from Ortho Technology Company, half of which had a 0.016 inch round and 0.019x0.025 rectangular. Ten specimens from both wire size were immersed in one of the tested fluoride prophylactic agents (neutral sodium fluoride gel, stannous fluoride gel or phos-flur mouth rinse) or in the controlled medium “normal salineâ€, and incubated at 37ËšC for sixty minutes. A Wp 300 universal material testing machine was modified and used to perform a three point bending test in a water path at 37ËšC ±1ËšC.The statistical difference between the different agents were analyzed using ANOVA and LSD tests. Results: The unloading forces at 0.5, 1.0, and 1.5 mm where significantly reduced especially in neutral sodium fluoride treated specimens. Conclusion: Based on the results founded in th study it might be preferred to use prophylactic agent with the least fluoride ions concentration.It can be concluded that the tested agents have only a limited effect on the load deflection behavior of the heat activated Ni-Ti wires, in a way that they do not have a clinically significant effect on the mechanical behavior of these wires.
The paper presents mainly the dynamic response of an angle ply composite laminated plates subjected to thermo-mechanical loading. The response are analyzed by analytically using Newmark direct integration method with Navier solution, numerically by ANSYS. The experimental investigation is to fabricate the laminates and to find mechanical and thermal properties of glass-polyester such as longitudinal, transverse young modulus, shear modulus, longitudinal and transverse thermal expansion. Present of temperature could increase dynamic response of plate also depending on lamination angle, type of mechanical load and the value of temperature.
In this work, the synergistic effect of chlorinated rubber (additive I),with zeolite 3A (additive II), zeolite 4A (additive III), and zeolite 5A (additive IV) in (1:1) weight percentage, on the flammability for unsaturated polyester resin was studied in the weight ratios for (3,7,10,13&15%) by preparing films of (130×130×3) mm in diameters. Three standard test methods used to measure were the flame retardation which are; ASTM: D-2863, ASTM: D- 635& ASTM: D-3014. Results obtained from these tests indicated that all of the additives were effective additive IV has the highest efficiency as a flame retardant.
This work presents a novel technique for the detection of oil aging in electrical transformers using a single mode optical fiber sensor based on surface plasmon resonance (SPR). The aging of insulating oil is a critical issue in the maintenance and performance of electrical transformers, as it can lead to reduce insulation properties, increase risk of electrical breakdown, and decrease operational lifespan. Many parameters are calculated in this study in order to examine the efficiency of this sensor like sensitivity (S), signal to noise ratio (SNR), resolution (refractive index unit) and figure of merit (FOM) and the values are for figure of merit is 11.05, the signal to noise ratio is 20.3, the sensitivity is 6.63, and the resolution is 3
... Show MoreThe adopted method in the teaching of history is conservation and indoctrination in all grades, and this will lead to a lack of students interact with teachers in the course of the lesson, and poor use of teachers to questions that raise students' thinking during the lesson, which leads to a lack of interest in the topic of the lesson and wasting opportunities contribution making it the teacher at the center of the educational process, and to provide arrogating the researcher to contribute to teaching style with the belief that the use of this method of teaching could lead to overcome the difficulties and problems faced by the teaching material.
And there are educational complexes integrated approac
... Show MoreAs a result of creative accounting, many firms in the Iraqi stock market are able to achieve two very significant goals: first, to boost the market value of their shares and thus gain the biggest trading volume in shares, and second, to lower their earnings in order to decrease the tax burden. First by growing its profits, then by evading taxes and denying the state its right to its money. Using this research, we hope to demonstrate how financial institutions that use innovative accounting tools in the preparation of their financial statements impact trade activity. Trading volume is critical to accurately forecasting stock price patterns, allowing investors to maximize their wealth. So, without accounting information, the financial
... Show MoreThis paper performance for preparation and identification of six new complexes of a number of transition metals Cr (lII), Mn (I1), Fe (l), Co (II), Ni (I1), Cu (Il) with: N - (3,4,5-Trimethoxy phenyl-N - benzoyl Thiourea (TMPBT) as a bidentet ligand. The prepared complexes have been characterized, identified on the basis of elemental analysis (C.H.N), atomic absorption, molar conductivity, molar-ratio ,pH effect study, I. Rand UV spectra studies. The complexes have the structural formula ML2X3 for Cr (III), Fe (III), and ML2X2 for Mn (II), Ni (II), and MLX2 for Co (Il) , Cu (Il).
Abstract
The Research Includes Two Variables : First , Academic Accreditation with his dimensions ( Educational Context , Educational Inputs , Educational Process , Educational Outputs , Feedback ) , And The Second : Strategic Performance With His dimensions ( Financing , Satisfaction Stakeholders , Internal Processes , Learning And Growth ) , The Research Highlights On The Academic Accreditation System Which Is Considered A Major And Important Systems Can Through Which Administration Of Activities And Programs Institutions Of Higher Education , As This research aims to determine his relationship And The Extent Of Its Effect In The Strategic Performance , And It Includes The Research C
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