Objective:Fluorid-containing dental alginate impression materials can exert a considerable reduction in
enamel solubility. The objective was to evaluate the effect of fluoride addition on the setting time and
compressive strength of alginate impression materials.
Methodology: 60 samples were constructed from alginate impression material (30 samples for setting
time test and 30 samples for compressive strength test).Specimens of each test divided into three
subgroup. Group A: 10 specimens of alginate were mixed with distilled water [control], Group B: 10
specimens of alginate were mixed with100-ppm fluoride and Group C:10 specimens of alginate were
mixed with 2%Naf.
Results: the result of setting time test showed that addition of 2% Naf to alginate impression materials
were delayed the setting reaction while the results of compressive strength test showed that high mean
values were obtained from control group while group mixed with 2%Naf had lower compressive
strength.
Recommendation: it can be concluded that addition of 100-ppm fluoride were affect on the
properties of alginate impression materials while addition of 2% Naf was deteriorated the properties of
alginate impression materials. So recommends the effect of fluoride addition in other concentration
The choice of gate dielectric materials is fundamental for organic field effect transistors (OFET), integrated circuits, and several electronic applications. The operation of the OFET depends on two essential parameters: the insulation between the semiconductor layer and the gate electrode and the capacitance of the insulator. In this work, the electrical behavior of a pentacene-based OFET with a top contact / bottom gate was studied. Organic polyvinyl alcohol (PVA) and inorganic hafnium oxide (HfO2) were chosen as gate dielectric materials to lower the operation voltage to achieve the next generation of electronic applications. In this study, the performance of the OFET was studied using monolayer and bilayer gate insulators. To mo
... Show More
The Research deals with the negative phenomena which appeared in the urban scenes of the Iraqi cities after 2003, particularly trespassing the architectural design of the urban Individual houses. Many academic researchers , critics, and cultural circles, drawn attention to the impact of political and cultural variable change on such phenomena without detailed analysis . The research problem is set according to central questions : If the phenomena is the trespass , what
are the sides which are being trespassed in the division of the individual house? , If the diagnosis of the phenomena denotes perceived repetition of the cases , So what's size of this transposes on the architectural design of t
The purpose of this study is designate quenching and tempering heat treatment by using Taguchi technique to determine optimal factors of heat treatment (austenitizing temperature, percentage of nanoparticles, type of base media, nanoparticles type and soaking time) for increasing hardness, wear rate and impact energy properties of 420 martensitic stainless steel. An (L18) orthogonal array was chosen for the design of experiment. The optimum process parameters were determined by using signal-to-noise ratio (larger is better) criterion for hardness and impact energy while (Smaller is better) criterion was for the wear rate. The importance levels of process parameters that effect on hardness, wear rate and impact energy propertie
... Show More
(2)
Many extracted material were used as mouthwash to settle different kinds of oral fungi and bacteria. In this study an extractive of Cyperus rotundus plant E.C.R. which is very active as a mouthwash, was used in concentration range (10-25) ppm in artificial saliva at pH=6.4 and temperature range (288-318) K, to study it’s inhibitory effect on the corrosion of dental amalgam. Potentiostatic and cyclic polarization were used to follow this study. The presence of E.C.R. lead to shift the corrosion potential to the active direction and decreased the corrosion rate to about 98.87%, the inhibition action of E.C.R. resulting from the adsorption of C.R.E. layer between amalgam and saliva as FTIR spectrums shows, where the variety of FTIR adsorptio
... Show More
(12)
(4)
Background: The aim of the study was to evaluate the amount of changes in the horizontal and vertical maxillary arch dimensions measurements following the premature loss of primary molars. Materials and methods: The sample consist of (50) children with unilateral prematurely extracted either first or second primary molars at the mixed dentition stage. Results and Conclusions: Results shows that there was an increase in the vertical incisor to canine distance (A) with both premature loss of first & second primary molars due to distal movement of primary canines and at the same time there were a significant loss of space in the extraction space with premature loss of second primary molar due to a mesial movement of maxillary first permanent
... Show MoreAbstract:- Cyberspace is a new arena for conflict between international powers, especially since the cost of cyber-conflict is less than its traditional warfare counterparts regardless of the nature of the weapons used, whether traditional or non-traditional. Cyber conflict is necessarily based on strategies to deter, attack, and defend. The aim of the cybercrime conflict is to ensure the defensive sufficiency of the state, ensuring its national security and safeguarding its supreme interests. Despite Japan-China relations characterized by convergence and cooperation in post-Cold War economic spheres, Japan continues to retain the growing Chinese influence in East Asia. These variables prompted Japan to announce a hedging strategy due to un
... Show MoreCu-Al-Ni shape memory alloy specimens has been fabricated using powder metallurgy technique with tube furnace and vacuum sintering environment , three range of Nb powder weight percentage (0.3,0.6,0.9)% has been added. Micro hardness and sliding wear resist has been tested followed by X-ray diffraction, scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDX) for micro structure observation. The experimental test for the samples has showed that the increase of Nb powder weight percentage in the master alloy has a significant effect on increasing the hardness and decreasing the wear resist therefore it will enhance the mechanical properties for this alloy.
(1)
A new simultaneous spectrophotometric-kinetic method was developed to determine phenylephrine (PHEN) and tetracycline (TETR) via H-point standard addition method (HPSAM). The proposed procedures rely on the measurements of the difference in the rate of charge-transfer (CT) reaction between each of PHEN and TETR as electron donors with p-Bromanil (p-Br) as an electron acceptor. Different experimental factors which affect the extent of the complex formation were investigated by monitoring the value of absorbance at 446 nm. Time pair of 50 -100 sec was selected and employed, among different examined pairs since it results in the highest accuracy for HPSAM-plot. Linear calibration graphs in the concentration ranges of 10.0-40.0 and 10.0–50.0
... Show MoreThe Ligand 6,6--(1,2-benzenediazo) bis (3-aminobenzoicacid) derived from o-phenylenediamine and 3-aminobenzoicacid was synthesized. The prepared ligand was identified by Microelemental Analysis, 1HNMR, FT-IR and UV-Vis spectroscopic techniques. Treatment of the ligand with the following metal ions (CoII, NiII, CuII and ZnII ) in aqueous ethanol with a 1:1 M:L ratio and at optimum pH. Characterization of these compounds has been done on the basis of elemental analysis, electronic data, FT-IR and UV-Vis, as well as magnetic susceptibility and conductivity measurements. The nature of the complexes formed were studied following the mole ratio and continuous variation methods, Beer's law obeyed over a concentration range (1×10-4 - 3×10-4 M). H
... Show More