Electron emission at very low electron impact energy: experimental and Monte-Carlo results

The behaviour of electron emission under electron impact at very low energy is of great importance in many applications such as high energy physics, satellites, nuclear reactors, etc. However the question of the total electron reflectivity is still in discussion. Our experimental and theoretical studies show that the total reflectivity at very low energy is far from being an obvious fact. Moreover, our results show that the yield is close to zero and not equal to one for low energy incident electron.Comment: 3 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Italy; CERN Yellow Report CERN-2013-002, pp.137-13

ECONOMIC EFFECTS OF INTENSIFYING THE USE OF AGRICULTURAL INPUTS AND MODERN TECHNOLOGIES ON THE WHEAT PRODUCTIVITY IN IRAQ.

This research aimed to illustrate the significant role of modern technology packages in agriculture, in particular in the growth of wheat cultivation. In this research will attempt to use O-Ring method. The purpose our using of this method is to prove that the modern technological packages used in agriculture, wheat cropping combined have a significant impact on increasing the productivity of the wheat crop in Iraq. A sample is taking from 290 farms, by divided into three governorates Namely Wasit, Babil and Diwaniyah. The packaging used to grow wheat was micronutrients, seeds, fertilizers, laser-level potassium sulphate, seeds, potassium sulphate fertilizers, Pallas herbicide, Atlantis herbicide and the farming cycle. All these elements were expressed; as A3i. This is an indicator of the intensification of agricultural inputs for developing wheat cultivation in Iraq. The results of the analysis showed that there is a high degree of correlation between each of the modern technological inputs and the rest of the modern inputs. The results also indicated that there is a growth and development in the productivity of the wheat crop because of the use of modern technologies, as there is a correlation between the use of the modern technology package and the development of the productivity of the wheat crop in Iraq

Splitting Arabic Texts into Elementary Discourse Units

International audienceIn this article, we propose the first work that investigates the feasibility of Arabic discourse segmentation into elementary discourse units within the segmented discourse representation theory framework. We first describe our annotation scheme that defines a set of principles to guide the segmentation process. Two corpora have been annotated according to this scheme: elementary school textbooks and newspaper documents extracted from the syntactically annotated Arabic Treebank. Then, we propose a multiclass supervised learning approach that predicts nested units. Our approach uses a combination of punctuation, morphological, lexical, and shallow syntactic features. We investigate how each feature contributes to the learning process. We show that an extensive morphological analysis is crucial to achieve good results in both corpora. In addition, we show that adding chunks does not boost the performance of our system

Numerical simulation of investment casting process of nickel-based alloy.

In this paper, we elaborated the nickel-based alloy type Hastelloy G30 and we analyzed it by techniques of characterization in order to interpret the results obtained through a computer simulation. The calculation of the thermo-physical properties of the alloy and the simulation of filling and solidification of the casting was performed by the software ProCAST. The validation of the numerical results was done by the following experimental techniques: optical microscopy and hardness test. In the center of the elaborate piece, the experimental results showed the appearance of porosity and leading to embrittlement of the alloy. According to the numerical simulation, this is caused by a fraction of the liquid that remains trapped in this area

Phase separation and chemical durability in the SiO2-B2O3-Na2O (SBN) glass system

Sodium borosilicates glasses were treated isothermically several times. In present work, the effect of phase separation on chemical durability and the electric resistivity was investigated. In addition, the effect of chemical composition and addition of calcium on the kinetics and rate of leaching of these glass materials in hydrochloric acid (3M HCl) was also investigated. The system studied exhibited phase separation starting from 550 ºC. Present results showed that the chemical durability was weakened upon phase separation. On the other hand, chemical durability increased with increasing SiO2 content and reducing the alkaline oxides (Na2O) content. Results also showed a drastic decrease in the ionic electric conductivity (increase in resistivity) with decreasing C = (Na2O + B2O3)/SiO2 (reduction of Na2O). The effect of chemical composition on the rate of leaching showed that boron and sodium are dissolved much more quickly than silicon. The greater the content of Na2O and B2O3 in glass, the more soluble the glass becomes. However, addition of silica results a decrease in glass solubility. These results indicate that substitution of sodium by calcium induces an acceleration of the kinetics of deterioratio