Theoretical study of the impact of quantum chemistry parameters on the behaviour al effect of the coating of a new epoxy prepolymer

The aim of our work is to evaluate the performance behavior of the coating of macromolecule epoxy matrix, tri glycidyl ether ethylene of bisphenol A (TGEEBA) on the corrosion of the carbon steel E24 in a marine environment and examine its mechanism of the coating. Subsequently, we have studied the possible adsorption model on the surface of the carbon steel E24 corroded and can explain the understanding of the interactions between the coating macromolecule and the surface of the carbon steel E24. The coating effect on carbon steel E24 was studied by quantum chemical calculations. The adsorption of TGEEBA on the surface of the carbon steel E24 has been well described by the model Quantitative Structure Property Relationship (QSPR).The mechanism of the behavior of the coating was determined by a potential of zero-load measurement and some electronic parameters. The prediction of the behavior of the coating was carried out by the method of three Becke compounds of the parameter (UB3LYP) whose semi-empirical basis are PM6 and DFT for an eventual composite. These last were used on the basis of (6-311 G). All calculations were performed using Gaussian software bias (03)

The 43GHz SiO maser in the circumstellar envelope of the AGB star R Cassiopeiae

We present multi-epoch, total intensity, high-resolution images of 43GHz, v=1, J=1-0 SiO maser emission toward the Mira variable R Cas. In total we have 23 epochs of data for R Cas at approximate monthly intervals over an optical pulsation phase range from 0.158 to 1.78. These maps show a ring-like distribution of the maser features in a shell, which is assumed to be centred on the star at a radius of 1.6 to 2.3 times the stellar radii. It is clear from these images that the maser emission is significantly extended around the star. At some epochs a faint outer arc can be seen at 2.2 stellar radii. The intensity of the emission waxes and wanes during the stellar phase. Some maser features are seen infalling as well as outflowing. We have made initial comparisons of our data with models by Gray et. al. (2009).Comment: 12 pages, 14 figure

Facies analysis and stratigraphic development of the Albian Succession in Nasiriyah Oil Field, Southern Iraq

The Carbonate - Clastic succession in this study is represented by the Nahr Uamr and Mauddud Formations deposited during the Albian Sequence. This study includes facies analysis and stratigraphic development for this succession in 5 boreholes within Nasiriyah oil field. There are several types of microfacies were recognized in the succession of the Mauddud Formation. Their characteristic grain types and depositional texture enabled the recognition of six facies associations (depositional environments) were distinguished in the Mauddud Formation, they are: shallow open marine, restricted, reef, slope, deep open marine and basinal. Two types of rocks are observed within the Nahr Umr Formation; the first is the upper part which characterized by shale dominated rocks and the second (lower part) is characterized by sand dominated rocks. Four facies associations (depositional environments) were distinguished in the Nahr Umr Formation, they are: delta plain, prodelta, bay fill, and distributary channels. The microfacies analysis and reconstructed the paleoenvironments of the Albain basin in the studied area; there are three stages of the deposition: - during the first stage the sea level was rise which led to progress prodelta facies (retrogradation) and onlapping the unconformity. This part is represented by TST stage in all studied boreholes. The prodelta facies was changed to distributary channel facies up-wared to mark the mfs between these two facies. This refers to deposition during the high stand period as two cycles. The sea level was reactivated to progress after the last step of Nahr Umr deposition, to start the Mauddud Formation deposition. At second stage the facies change was shown three steps of the sea level rise (TST) to deposition the restricted, reef-back reef and shallow open marine/slope. Overlying the slope facies to the shallow marine and then deposited the shallow marine refer to maximum flooding surfaces after deposition the last ones. Therefore, the shallowing up-ward succession which deposition later was represented the high stand stage (HST). The final stage is represented by reactivated the sea level rise to deposition the basinal facies within the Mauddud Formation. The continued rise in sea level during the period of transgression (TST) is a preparation for the Ahmadi basin, which is characterized by deposition in a deep environment and conformable lower contact with the Mauddud Formation

Smart Visualization for Online Aids Image Retrieval

Visual aids can be considered as a motivational tool in enhancing students’ attention and create positive perceptions. The use of new technologies has opened new possibilities to integrate online visual aids in the teaching process, which produce positive learning effects. In this paper, a novel technique employed to retrieve specific images based on the kind of query classification. The semantic dictionary built based on the specific classification correlate with the query intention. Singular Value Decomposition SVD training technique have been used to select the effective key templates in order to link the query with the web annotation directly. The present method can be considered as a strategic tool in the E-learning technique, which can provide variety of clustered images to help the students in creative and critical thinking skills and prevent the indoctrination method in learning the students. The qualitative results achieved high True Positive (TP) retrieved images that respect to the effectiveness of the E-learning task. Also, it provides a good 92% of learning reaction and superior learning behavior level

New matrix cement-zeolite for the cementation of radioactive waste: study of the physical properties and mechanical performances

In the aim to improve the physical properties and the mechanical performance of the confinement matrix of spent of use Ion Exchange Resin (IER) considered among the radioactive waste of low and medium activity of long-lifetime, various formulations of the cementitious matrix based of different percentages of zeolite raining form 2% to 10% by weight of cement with a step of 2% have been developed. The physical properties (compactness) and the mechanical performance (the compressive strength) of the new cement- zeolite matrix have been investigated.The obtained experimental results from the different formulations elaborated showed that the partial substitution of cement by the zeolite improves significantly the physical properties and the mechanical performances of the last one, this is due mainly to the pozzolanic properties of zeolite related to their reactive SiO2 and Al2O3, Which react with Ca(OH)2, released during the hydration of cement and transforming it into aluminates and gels C-S-H. In consequence, the microstructure of the hardened cementitious matrix has improved; its compactness and its mechanical resistance of compression were increased also

Reduction of pavement thickness using a subgrade layer treated by different techniques

A range of stabilisers for poor quality subgrade soils have been developed to promote road constructions. Many of them are becoming more popular depending on their effectiveness. The purpose behind this research is to identify the relative efficacy of many physical and chemical stabilisation techniques for enhancing the properties of three types of local Iraqi subgrade soils. The comparison of the samples is based on the CBR tests. The AASHTO (1993) flexible pavement design was used to compute the pavement thickness requirements. The soil samples A, B and C have a natural CBR values of 3.8, 3.9 and 4, respectively, on which the physical stabilisers of Powdered rock (PR), grained recycled concrete (GRC), and recycled crumb rubber grains (CR) were employed, while Quicklime (QL) and activated fly ash (AFA) were both utilised as chemical stabilisers. The stabilisation with 15 % of AFA proved to be the most applicable method for soil types A and B for reducing the pavement thickness requirements by 51 % and 32 %, respectively, with a reasonable financial feasibility for both. The same feasibility is proven when stabilising soil type C with 15 % of GRC, which reduces the pavementthickness by 25.7 %

Possibility of Detection of Exomoons with Inclined Orbits Orbiting Pulsar Planets Using the Time-of-Arrival Analysis

The perturbation caused by planet-moon binarity on the time-of-arrival (TOA) signal of a pulsar with an orbiting planet is derived for the case of the orbit of the planet-moon system inclined of an angle α with respect to the plane of the orbit of the planet-moon barycenter around the pulsar. We also consider both the orbits of the moon and the planet-moon barycenter as circular. The signal consists of three sinusoids with frequency, respectively, of (2np−3nb), (2np−nb), and (2np−3nb), where np and nb are, respectively, the mean motions of the planet and moon around their barycenter and the planet-moon system around the host, respectively. The amplitude of the signal is equal to the fraction sin⁡I[9(Mp/Mm)/16(Mp+Mm)2][r/R]5(5 sin⁡2α/3−2sin⁡α/3−2 cos⁡2α/9) of the system crossing time R/c, where Mp and Mm are, respectively, the mass of the planet and the mass of the moon, r is their orbital separation, R is the distance between the host pulsar and planet-moon barycenter, I is the inclination of the orbital plane of the planet, and c is the speed of light

Experimental Study Of Natural Convection Heat Transfer In An Enclosed Vibration Cavity

Experimental study has been implemented to elucidate an affect of mechanical vibration at  normal gravity on natural convection in cubic enclosure  side (L=120mm) filled with air ( 14Pr=0.71)">  at two amount of heat flux (. The enclosure was comprised of two vertical and opposed surfaces. The right wall was heated at uniform heat flux where the left wall cooled was maintained at 14Tc"> , surrounded by four other adiabatic surfaces. Vibration stresses were applied to this heat transfer cell by mounting it vertically on the armature of electrodynamic vibratior. The experiments were carried out at for Rayleigh number range ( 147*107-4*108)"> and aspect ratio equal (1), frequencies from 2to 8 Hertz at 14q""> =85 14Wm2">  and from 3 to 9 Hertz at 946.017 14Wm2"> ). In the high Rayleih number case (Ra=4* 14108"> ), the gravitional thermal convection dominates, and the vibration motion does not enhances the heat transfer remarkably. In contrast, in low Rayleigh (Ra=7* 14107"> ), the vibration thermal convection is dominant, and the vibration enhaces the heat transfer rate significantly. In addition, the higher the vibration frequency is, the quicker the steady stateis reached and for two cases of Rayeigh number at ascending frequencies is in general higher than that descending frequencies. Keywords: Cubic Enclosure, Mechanical Vibration

Blockchain-based student certificate management and system sharing using hyperledger fabric platform

One of the major capabilities of blockchain technology is the sharing of data in verifiable ways without losing control of information possession. Issuing and verifying student certifications for higher study applications or job recruitment require many steps that take days to complete and are considered time-consuming. Most universities around the world use centralized systems to control the entire procedure when a graduate applies for a job or postgraduate studies. Applying blockchain technology to certificate verification protocols through a comprehensive architecture provides authenticity and reduces time significantly. In this paper, a framework has been proposed to issue student certifications locally in addition to sharing them across the internet while maintaining control and ownership of the certifications. This framework leverages the advantages of blockchain technology to electronic certification sharing and verification. Applying the proposed blockchain-based certification system in universities will provide low latency for issuing, sharing, and verification of these certifications. The paper presents the proposed blockchain-based framework for e-certification sharing and an evaluation of the framework, which consists of measuring the average time to issue a certificate and transaction latency time.</p

Enhancement of electrochemical properties of micro/nano electrodes based on TiO2 nanotube arrays

Titanium oxide nanotube (TiO2 nanotube) arrays were produced by anodizing titanium foils in two different electrolytes. The first electrolyte consisted of ethylene glycol containing 0.5 wt% NH4F and 4 vol% of distilled water to produce pure TiO2 nanotube arrays and the second consisted of HF aqueous solution (0.5 wt%) containing 0.5% polyvinylalcohol to produce carbon doped TiO2 nanotube arrays. The fabricated TiO2 nanotube arrays were subsequently annealed in the atmosphere of nitrogen. The morphology and crystal structure of fabricated arrays were characterized by means of scanning electron microscopy and X-ray diffraction. The electrical conductivity and capacitance of TiO2 nanotube arrays were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Water contact angle and biocompatibility of fabricated nanotube arrays were investigated. The results showed that carbon doped TiO2 nanotube arrays annealed in the atmosphere of nitrogen have higher conductivity and capacitance than those of pure arrays annealed in the same atmosphere. Doping with carbon enhances the biocompatibility and wettability of TiO2 nanotube arrays. It has also noted that electrical conductivity and capacitance of TiO2 nanotube arrays were directly proportional to the tube wall thickness