Dental amalgam is a mixture of approximately 50% mercury and varying ratios of silver, tin, zinc, and copper. Dental amalgam is a major source of mercury pollution because it is readily absorbed through 90-100% vapour and the oral mucosa. In addition, in certain situations with the oral environment, various types of metallic orthodontic brackets are highly aggressive and can lead to corrosion. However, polyvinyl alcohol (PVA) material has no cytogenetic effects on human health or the environment and is therefore applied in the manufacturing of the new composite material. Different additives from the bonding agent (PVA; 2.4, 4.8, and 7.2 g)  dissolved in about 10 ml of water, heated on a hot plate under a hig

Hedging is a linguistic avoidance of full commitment or precision. It is the use of a vague language. The main objectives of this study are to

An indirectly method is used to determine hydrogen peroxide. The method based on oxidation of chromium (III) ion by hydrogen peroxide in basic medium to form chromate ion which react with barium (II) ion to produce a yellow precipitate (BaCrO4). Under the optimum established conditions, the linear range of 0.50-25.00 mmol L-1 along with correlation coefficient (r) of 0.9992, Limit of detection (LOD) 0.68 μg / 100 μL, precision expressed as relative standard deviation for six replication measurements at 5.0 mmol.L-1 H2O2 of less than 2% were obtained for hydrogen peroxide. The developed method was successfully applied for the estimation of H2O2 in three pharmaceuticals preparation of different companies using continuous flow injection o

A new flow injection spectrophotometric method is described for the determination of copper ion Cu(II) in water samples (tap water and river water).The proposed method based on the formation of red complex [Cu(L)2(NO3)2] which has a maximum absorption at λmax=490 nm. Linear range for Cu (II) was from 5-70μg/mL with detection limit 2.55μg/mL. The effect of physical and chemical parameters were evaluated .The proposed method was applied successfully for determination of copper (II) in the tap and river water. [Cu(L)2(NO3)2] complex was prepared in a (2:1) mole ratio as ( reagent: copper (II)).The analytical reagent formed by reaction of thymol with 4-aminoantipyrine at room temperature. The metal complex was characterized by IR, UV-Visi

This paper demonstrates the construction of a modern generalized Exponential Rayleigh distribution by merging two distributions with a single parameter. The "New generalized Exponential-Rayleigh distribution" specifies joining the Reliability function of exponential pdf with the Reliability function of Rayleigh pdf, and then adding a shape parameter for this distribution. Finally, the mathematical and statistical characteristics of such a distribution are accomplished

In this article, it is interesting to estimate and derive the three parameters which contain two scales parameters and one shape parameter of a new mixture distribution for the singly type one censored data which is the branch of right censored sample. Then to define some special mathematical and statistical properties for this new mixture distribution which is considered one of the continuous distributions characterized by its flexibility. Next,  using maximum likelihood estimator method for singly type one censored data based on the Newton-Raphson matrix procedure to find and estimate values of these three parameter by utilizing the real data taken from the National Center for Research and Treatment of Hematology/University of Mus

In this paper, we introduce and study a new concept named couniform modules, which is a dual notion of uniform modules, where an R-module M is said to be couniform if every proper submodule N of M is either zero or there exists a proper submodule N1 of N such that is small submodule of Also many relationships are given between this class of modules and other related classes of modules. Finally, we consider the hereditary property between R-module M and R-module R in case M is couniform.