In the current work various types of epoxy composites were added to concrete to enhance its effectiveness as a gamma- ray shield. Four epoxy samples of (E/clay/B4C) S1, (E/Mag/B4C) S2, (EPIL) S3 and (Ep) S4 were used in a comparative study of gamma radiation attenuation properties of these shields that calculating using Mont Carlo code (MCNP-5). Adopting Win X-com software and Artificial Neural Network (ANN), µ/ρ revealed great compliance with MCNP-5. By applying (µ/ρ) output for gamma at different energies, HVL, TVL and MFP have been also estimated. ANN technique was simulated to estimate (µ/ρ) and dose rates. According to the results, µ/ρ of all epoxy samples scored higher than standard concrete. Both S2 and S3 samples having higher values of µ/ρ, show minimum dose rate values. (µ/ρ) and RPE% values were enhanced, the concrete containing E/Mag/B4C (S2) had the best results, while the concrete containing Ep (S4) provide the worst results. The ANN prediction results take 15 sec for estimating gamma doses corresponding to seventeen shield thicknesses, while the theoretical MCNP-5 results took approximately between 7 to 10 hours for five gamma doses. ANN provides excellent predictions with a high degree of correlation depending on increasing the number of attenuation parameters used in the training process. Also, it predicts gamma dose rates for a large number of shield thicknesses that cannot be calculated theoretically in a very short time. This supports, the created epoxy composite offers good attenuation properties for many shielding applications and could be proposed as an injecting mortar for cracks in biological shields and the walls of diagnostic and radiotherapy rooms. However, further investigations are planned for different filler ratios, for comparison purposes, in order to reach optimal shielding properties
In this work, the technique of attenuation of gamma ray to calculate the density of comet nucleus materials (C/2009 P1 (GARRADD) at different range of energy (0.2- 0.9 MeV). also, the single scattering model for gamma rays has been assumed that photons reaching the detector with scattered only once in the material. The program has been designed and written in FORTRAN language (77 – 90) to calculate the density for molecules using Monte Carlo method was used to simulate the scattering and absorption of photons in semi- infinite material. Gamma ray interacts with the matter by three mainly interactions: Photoelectric effect, Compton scattering and Pair production (electron and positron). On the 137Cs source energy (662 keV), Compton scat
... Show MoreLong memory analysis is one of the most active areas in econometrics and time series where various methods have been introduced to identify and estimate the long memory parameter in partially integrated time series. One of the most common models used to represent time series that have a long memory is the ARFIMA (Auto Regressive Fractional Integration Moving Average Model) which diffs are a fractional number called the fractional parameter. To analyze and determine the ARFIMA model, the fractal parameter must be estimated. There are many methods for fractional parameter estimation. In this research, the estimation methods were divided into indirect methods, where the Hurst parameter is estimated fir
... Show MoreNegotiations in administrative contracts represent an important preparatory stage in which discussions and discussions between the administrative authority and the party wishing to contract with them will be held on one of the issues related to the contract to be concluded whereby the different views of the parties of the contractual relationship are brought together to exchange or achieve common interests.
The importance of negotiations in administrative contracts and their significant and effective role in protecting state funds. The inadequacy of Iraqi legislation in the development of an integrated legal framework for this important phase, and the many problems that appear in this stage before the conclusion of the cont
... Show MoreCriminal prescription is a legal idea that we find its applications in most laws, It means that a period of time has passed since the occurrence of the crime, which is called the prescription of the criminal case or the crime, or the lapse of a period of time since the issuance of a final judgment in the criminal case, and it is called the prescription of the penalty, the lapse of the prescribed period will result in the expiry of the criminal case in the first case, and the lapse of the penalty imposed in the second case. This system has been found since ancient times in the legislation of countries with their various legal and political systems because of its practical considerations, the most important of which is achieving legal stab
... Show MoreThe exception of contract non-Performance represents an important mechanism in the implementation of obligations. It enables a contractor to refrain from implementing its obligation until the other party has fulfilled its obligations. It is a means of defense, pressure and guarantee of its rights. It is stipulated in articles 161 of the Egyptian Civil Code and Article 123 of the Civil Code While it was not provided for in the French Civil Code except after the issuance of Order No. 2016-131 on the reform of the system of contracts and public order and the establishment of obligations in articles 1217, 1219 and 1220 thereof. These texts, although they did not show the basis on which the exception of contract non-Performance, leaving this
... Show MoreHand-lay up method was used to prepare the samples made of epoxy (EP) as a matrix reinforced with chopped carbon fibers (CCF). The fatigue behavior of epoxy resin /chopped carbon fiber composites was studied with different weight percentage of chopped carbon fibers (2.5%,5%,7.5%,10%,12.5%). The fatigue test was carried out under alternate bending method, which was made by applying sinusoidal wave with constant displacement (15mm), stress ratio R=-1,and loading frequency 10Hz, which is believed to give a negligible temperature rise during the test. The results of the maximum stress, fatigue strength, fatigue limit and fatigue life of the tested composites are calculated from stress(S)-number of cycles(N) (S-N) curves.
It was shown that
In this study a polymeric composite material was prepared by hand
lay-up technique from epoxy resin as a matrix and magnesium oxide
(MgO) as a reinforcement with different weight fraction (5,10,15,
and 20)% to resin. Then the prepared samples were immersed under
normal condition in H2So4(1 M) solution, for periods ranging up to
10 weeks. The result revealed that the diffusion coefficient
decreasing as the concentration of MgO increase. Also we studied
Hardness for the prepared samples before and after immersion. The
result revealed that the hardness values increase as the concentration
of MgO increase, while the hardness for the samples after immersion
in H2SO4 dec
The issue of human rights occupies great importance on the academia as well as in the reality, especially after the spread of ideas related to these rights on one hand and the large number of violations they are exposed to on the other hand, which makes it necessary to develop fundamental solutions to the remove the obstacles of implementing human rights.
In this research entitled (The Legal Basis of the Right to the City: A Comparative Study) we dealt with a new concept of human rights and discussed the basis upon which it is based in international charters, constitutions and domestic laws.
Overlapped have been prepared from epoxy resin material added to carbon Nanotube and percentages weight (0.1, 0.05, 0.01) % Studied the mechanical properties of the composite (bending, tensile an d hardness) has been found that the Flexural and tensile modulus of the composites were higher than the pure epoxy resin this may be due to the high mechanical strength of carbon nano tube (CNT). The hardness of the epoxy carbon Nanotube composites increased and the reason is due to increased overlap and stacking between the additives and material basis, which reduces the movement of polymer molecules leading to increased resistance to scratching material and cutting, will become more resistance to plastic deformation.
The scope of the electrical power facility is determined by its employees' mistakes as follows and subject to its control and guidance, as well as those affiliated with mechanical machines or dangerous things that require special attention, and can be denied the responsibility based on a number of means to which the defendant is resorted to it, the law has been granted For the requirements of justice and to judge the judiciary in many of the provisions issued by an investigation into the principle of equity. The most important mistakes, which are the most important means that the electric power facility can resort to existing responsibility in accordance with Article (219) of the Iraqi Civil Law, which is responsible for fulfilling acts,
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