The synthesis of nanoparticles (GNPs) from the reduction of HAuCl₄ ^.3H₂O by aluminum metal was obtained in aqueous solution with the use of Arabic gum as a stabilizing agent. The GNPs were characterized by TEM, AFM and Zeta potential spectroscopy. The reduction process was monitored over time by measuring ultraviolet spectra at a range of λ 520-525 nm. Also the color changes from yellow to ruby red, shape and size of GNP was studied by TEM. Shape was spherical and the size of particles was (12-17.5) nm. The best results were obtained at pH 6.

Stereolithography (SLA) has become an essential photocuring 3D printing process for producing parts of complex shapes from photosensitive resin exposed to UV light. The selection of the best printing parameters for good accuracy and surface quality can be further complicated by the geometric complexity of the models. This work introduces multiobjective optimization of SLA printing of 3D dental bridges based on simple CAD objects. The effect of the best combination of a low-cost resin 3D printer’s machine parameter settings, namely normal exposure time, bottom exposure time and bottom layers for less dimensional deviation and surface roughness, was studied. A multiobjective optimization method was utilized, combining the Taguchi me

  Tax state institution regards as one of the largest state institutions implementing the tax rules issuing be legislative body and achieving the goals of tax (financial, economic, social and political). So, the tax management should pay attention to the procedures enabling it to achieve those rules starting from the procedures of tax restrict and ending by tax allocation where the process of assessment the taxation must relaxing on modern methods. The problem of the study raising from that in spite of there is a low  obliging the taxable person (registered or not) to submit a declaration about his income and the achieved profit to be the base of taxation˒ where the other ways  are secondary ways helping in rejection of t

The past decades have witnessed a development in the concept of corporate governance and the transformation of a concept that is limited to large companies listed in capital markets in major economies to an issue that concerns all business activities in the public and private sectors in both large and small countries. The aim of this research is to propose a guide to the mechanisms and rules of governance in the municipal institutions that contributes to the activation of the internal control system to reduce the fraud and manipulation of this activity. Institutions. The research was based on the hypothesis that the implementation of the principles and rules of governance in municipal institutions lead to the contribution of the activati

Determination of the sites of geographical coordinates with high accuracy and in short time is very important in many applications, including: air and sea navigation, and in the uses geodetic surveys. Today, the Global Positioning System (GPS) plays an important role in performing this task. The datum used for GPS positioning is called World Geodetic System 1984 (WGS84). It consists of a three-dimensional Cartesian coordinate system and an associated ellipsoid so that WGS84 positions describe coordinates as latitude, longitude and ellipsoid height (h) coordinates, with respect to the center of mass of the Earth This study develops a mathematical model for geomantic measurement correction for ellipsoidal heights (h) between two different

The process of evaluating data (age and the gender structure) is one of the important factors that help any country to draw plans and programs for the future. Discussed the errors in population data for the census of Iraqi population of 1997. targeted correct and revised to serve the purposes of planning. which will be smoothing the population databy using nonparametric regression estimator (Nadaraya-Watson estimator) This estimator depends on bandwidth (h) which can be calculate it by two ways of using Bayesian method, the first when observations distribution is Lognormal Kernel and the second is when observations distribution is Normal Kernel

Flexible molecular docking is a computational method of structure-based drug design to evaluate binding interactions between receptor and ligand and identify the ligand conformation within the receptor pocket. Currently, various molecular docking programs are extensively applied; therefore, realizing accuracy and performance of the various docking programs could have a significant value. In this comparative study, the performance and accuracy of three widely used non-commercial docking software (AutoDock Vina, 1-Click Docking, and UCSF DOCK) was evaluated through investigations of the predicted binding affinity and binding conformation of the same set of small molecules (HIV-1 protease inhibitors) and a protein target HIV-1 protease enzy

A preventing shield for neutrons and gamma rays was designed using alternate layers of water and iron with pre-fixed dimensions in order to study the possibility of attenuating both neutrons and gamma-rays. ANISN CODE was prepared and adapted for the shield calculation using radiation doses calculation: Two groups of cross-section were used for each of neutrons and gamma-rays that rely on the one – dimensional transport equation using discrete ordinate's method, and through transforming cross-section values to values that are independent on the number of groups. The memory size required for the applied code was reduced and the results obtained were in agreement with those of standard acceptable document samples of cross –section, this a

This paper describes theoretical modeling of electrostatic mirror based on two cylindrical electrodes, A computational investigation has been carried out on the design and properties of the electrostatic  mirror. we suggest a mathematical expression to represent the axial potential of an electrostatic mirror. The  beam path  by using the Bimurzaev technique have been investigated as a mirror trajectory with the aid of Runge – Kutta  method. the electrode shape of mirror two electrode has been determined by using package SIMION computer program . The spherical and chromatic aberrations coefficients of mirror has been computed and normalized in terms of the focal length. The choice of the mirror depends on the op

  In this work, the theoretical study for designing of dielectric mirrors of high reflectance in the visible region of electromagnetic spectrum between wavelength of 400-700 nm is presented, and searching on the performance properties of the design, like there reflectance as a function to the wavelength, as beam incident in a normal form, for the materials of neglected absorbance, and scattering, in the form of thin film deposition, which are deposited on glass substrate, and by using matrix system in the study, which are used as computer simulation in MATLAB code.      The materials which are used in this study are represented by ( AlAs ), (TiO2 ),( SiC ), and  (Si3N4 ), which used in the designing mirrors alter