In order to examine the protection A postulated initiating event is explored step insertion of a positive reactivity in order to investigate the safety of the reactor of the Tajoura Nuclear Research Reactor with Low Enriched Uranium (LEU). These initiated events are:; a reduction of flow of primary coolant; and a loss of flow accident (LOFA) followed by a reversal flow. PARET computer code is implemented to simulate those suggested initiating events. The transient thermal hydraulic analysis is obtained at both the hottest and averaged cells of the core. The simulation is carried out at the operating power of 10 MW and the inlet coolant temperature equals to 45°C. The results exhibit that the worst case of those examined postulated events is by adding a 1.5$ ramp positive reactivity to the core when the resultant maximum clad surface temperature reaches 130.3°C.

Although the third wave of democratization overturned autocracies around the world, Libyan and Egyptian regimes stayed afloat for a long period. Libya and Egypt were ruled by dictatorial regimes for decades, but there were varying degrees of tyranny in both countries. One means of comparing political transition in Libya and Egypt is to examine both regimes’ structures. Qaddafi’s regime was a personalistic regime that lacked the genuine institutions that could rein in Qaddafi's singularity by power and by ruling the country. In contrast Mubarak regime was seen as a hybrid regime in that it apparently combined democratic and authoritarian institutions, but in reality, it was a dictatorship regime. Mubarak regime used democratic institutions as a facade to hide the real nature of the regime .The political system is dominated by the president, who has strong legislative powers and can dissolve parliament. Keywords: political transition, military institution, civil war

Herein, graphene (GN) was synthesized, exfoliated by anchoring dodecyl sulfate chain through hydrophobic interaction over its surface (GN-SDS), and was tested to sequester Cu(II) and Mn(II) ions in single-metal system from aqueous phase. Acid-base titrations and elemental analysis results verified successful dodecyl sulfate chain anchoring over GN-SDS surface. Adsorption/desorption isotherms depicted Type-IV isotherm with H3 type hysteretic loop, confirming mesoporous nature of GN-SDS with BET surface area – 242 m2/g. The ID/IG ratios of GN and GN-SDS obtained by RAMAN spectroscopy were 0.8537 and 0.8540, respectively confirming no distortion in structure during modification. Electrostatic interaction between metal ions and negative surface charge and-/or Cπ electrons of GN-SDS was governing the adsorption process. Maximum Cu(II) and Mn(II) adsorption on GN-SDS was observed at pH 5 and 6, respectively. Rapid Cu(II) and Mn(II) adsorption kinetics accomplishing 80–92% and 87–96%, respectively at varied concentration in 60 min was observed. Maximum adsorption capacities for Cu(II) and Mn(II) on GN-SDS were 369.16 and 223.67 mg/g, respectively. Langmuir isotherm and pseudo-second-order kinetic models were fitted to experimental data. Thermodynamically favorable adsorption process was observed. 30–33% drop in GN-SDS adsorption potential for Cu(II) and Mn(II) after five consecutive regeneration cycles was observed.

Abstract— With the growth of digital Arabic documents specially in information retrieval (IR) and natural language processing (NLP) applications, identification of irregular plurals which are commonly called broken plurals (BP) in modern standard Arabic becomes very urgent issue. Broken plurals are formed by imposing interdigitating patterns on stems, and singular words cannot be recovered by standard affix stripping stemming techniques. Identifying broken plurals is an important and difficult problem which needs to be addressed. In information retrieval, deriving singulars from plurals is referred to as a stemming. The process of stemming can be achieved by removing the attached affixes from a given word. To the best of our knowledge, all existing Arabic stemmers are unreliable and still under research. Consequently, this paper proposes an approach which identifies broken plurals without the need to perform the stemming process on any given word. The well known decision tree system (WEKA J48) is applied to build a classifier (model) on a very huge Arabic corpus as a training data which is pre-processed and prepared as a piece of this work. The built classifier is evaluated using unseen test set. The obtained results reveal that a very promising broken plural recognizer could be designed and implemented for NLP applications.

Abstract

The main purpose of catalytic reforming unit is to upgrade low-octane naphtha to high-octane gasoline. In this work, the estimation capacities of the response surface methodology (RSM) and artificial neural network (ANN), to determine the research octane number (RON) of reformates produced from the catalytic naphtha reforming unit were investigated. The article presents a comparative study and combined application between response surface methodology (RSM) and artificial neural networks (ANN) based on design of experiment (DOE) strategy in the modeling and prediction of the research octane number (RON). In this study, DOE⿿CCRD full factorial design was incorporated into the ANN methodology, so the need of a large quantity of training data was avoided. ANN methodology showed a very obvious advantage over RSM for both data fitting and estimation capabilities. Based on the results of analysis of variance (ANOVA), a multiple determination coefficient of 0.8 and 0.99 were obtained for both RSM and ANN respectively. It has been found that by employing RSM approach coupled with ANN model based on DOE strategy, the visualization of the experimental points in three dimensional spaces can disclose qualitatively and quantitatively the activity relationships. This approach of combination of RSM⿿ANN⿿DOE has revealed its ability to solve a quadratic polynomial model involving solving, optimization, complexity and difficult relationships especially nonlinear ones may be investigated without complicated equations involved. The study revealed that, the maximum RON of 88 was obtained at the optimum conditions offered by RSM. Furthermore, at the optimal conditions of (T = 521 °C, P = 37.6 bar, LHSV = 2.02 h⿿1), the maximum RON of 98 was obtained for the ANN model. However, the models were implemented for the construction of 3D response surface plots from the ANN and RSM models in order to show the most effective variables as well as the effects of their interaction on the research octane number.