Ab – initio restricted Hartree - Fock method within the framework of large unit cell (LUC) formalism is used to investigate the electronic structure of Si and Ge nanocrystals. The surface and core properties are investigated. A large unit cell of 8 atoms is used in the present analysis. Cohesive energy, energy gap, conduction and valence band widths are obtained from the electronic structure calculations. The results are compared with available experimental data and theoretical results of other investigators. The calculated lattice constant is found to be slightly larger than the corresponding experimental value because we use only 8 atoms and we compared the results with that of the bulk crystals, nanoclusters are expected to have stronger directional bonds that in their bulk structure. The surface states are found to be mostly non-degenerated because of the effect of surface discontinuity and the existence of oxygen atoms. Valence and conduction bands are found to be wider on the surface due to the splitting of energy levels due to the existence of oxygen atoms. The present method can be used to investigate the electronic structure of bulk, surface and nanocrystals.
This work concerns the synthesis of two types of composites based on antimony oxide named (Sb2O3):(WO3, In2O3). Thin films were fabricated using pulsed laser deposition. The compositional analysis was explored using Fourier transform infrared spectrum (FTIR), which confirms the existence of antimony, tungsten, and indium oxides in the prepared samples. The hall effect measurement showed that antimony oxide nanostructure thin films are p-type and gradually converted to n-type by the addition of tungsten oxide, while they are converted almost instantly to n-type by the addition of indium oxide. Different heterojunction solar cells were prepared from (Sb2O3:WO
... Show MoreOne of the main techniques to achieve phase behavior calculations of reservoir fluids is the equation of state. Soave - Redlich - Kwong equation of state can then be used to predict the phase behavior of the petroleum fluids by treating it as a multi-components system of pure and pseudo-components. The use of Soave – Redlich – Kwon equation of state is popular in the calculations of petroleum engineering therefore many researchers used it to perform phase behavior analysis for reservoir fluids (Wang and Orr (2000), Ertekin and Obut (2003), Hasan (2004) and Haghtalab (2011))
This paper presents a new flash model for reservoir fluids in gas – oil se
III-V zinc-blende AlP, AlAs semiconductors and their alloy Aluminum Arsenide phosphide Al AsxP1-x ternary nanocrystals have been investigated using Ab- initio density functional theory (Ab-initio-DFT) at the generalized-gradient approximation (GGA) level with STO-3G basis set coupled with large unit cell method (LUC). The dimension of crystal is found around (1.56 – 2.24) nm at a function of increasing the sizes (8, 16, 54, 64) with different concentration of arsenide (x=0, 0.25, 0.5, 0.75 and 1) respectively. Gaussian 03 code program has been used throughout this study to calculate some of the physical properties such as the electronic properties energy gap, lattice constant, valence and conduction band as well as density of state. Re
... Show MoreBig data analysis has important applications in many areas such as sensor networks and connected healthcare. High volume and velocity of big data bring many challenges to data analysis. One possible solution is to summarize the data and provides a manageable data structure to hold a scalable summarization of data for efficient and effective analysis. This research extends our previous work on developing an effective technique to create, organize, access, and maintain summarization of big data and develops algorithms for Bayes classification and entropy discretization of large data sets using the multi-resolution data summarization structure. Bayes classification and data discretization play essential roles in many learning algorithms such a
... Show MoreIn this paper, the static analysis for finding the best location of boxes inside the composite wing-box structure has been performed. A software ANSYS (ver.11) was used to analyses the Aluminum wing to find the maximum stresses reached in. These results are used as a base for the composite wingbox to find the numbers of layers and location of the box beam and its dimensions so that the composite wingbox may carry the same loading conditions in the Aluminum wing. Analysis showed that a composite wingbox having two boxes is better than the single or triple boxes wing based on stress to weight ratio. Mass saving of (40%) had been achieved when composite wing-box is used instead of Aluminum wing.
The aquatic crude extract of Silybum marianum dry grains prepared by melting them in distil water by the method of soak and shake. The effect of Silybum marianum crude extract studied in vitro on three tumor cell line the Hep-2, AMN-3 and RD for 24, 48 and 72 hours of exposure, and one cell line of normal cells REF for 72 hr exposure. The results showed that the prescence of toxic effect of the aquatic crude extract on the cell lines of Hep-2, AMN-3 and RD at 10 and 100 µg/ ml upto the higher concentrations when they exposed to the extract for 48 hr. as compared with the control treatment, and when the exposure period increased to 72 hr. the toxic effect started at low concentrations (5 and 10 µg/ ml) as compared with the control g
... Show MoreThis research discusses the subject of identity in the urban environment as it attempts to answer a number of questions that come with the concept of identity. The first of these questions: What is identity? Can a definition or conceptual framework be developed for identity? What about individual, collective, cultural, ethnic, political and regional identity? Is there a definition of identity in the urban environment in particular? If there is a definition of identity, what about social mobility responsible for social change? How can we see identity through this kinetics? Can we assume that identity in the urban environment has a variable structure or is of variable shape with a more stable structure? Can we determine the spatial-tempora
... Show MoreThe e-news is one of the most important journalistic arts in new media (the Internet). The process of telling the story by the journalist is an important aspect of the communicative process between the users of the internet and the reporter. The electronic news is characterized by having text, fixed images, animations, videos and sound. All these give greater vitality to the communicative process and increase the semiotic dimensions. Also, it makes the narrative process more distinctive and embodied of the elements of the event. This research studies all these aspects and tries to show the distinction between the semiotics of narration and the electronic news.