Ensemble Monte Carlo Electron Transport Simulation for GaN n+–n–n+ Diode

Baghdadi Berrabah,Choukria Sayah,Souheyla Ferouani,Sofiane Derrouiche,Benyounes Bouazza 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.3

Ensemble Monte Carlo simulator is used for solution of Boltzmann transport equation coupling with Poisson equation. We study the electron transport in cubic GaN n+–n–n+ for voltages range from 0.5 to 4 V. In this simulation technique, spatial motion of electron is treated semi-classically and scattering mechanisms included are those due to phonons scattering and ionized impurities scattering. Profile of the electron density, average velocity, kinetic energy, electrostatic potential and electric field are computed. Results are reported for diff erent lattice temperature and various active layer lengths.

Dental maturity of Saudi children: Role of ethnicity in age determination

Baghdadi, Ziad D. Korean Academy of Oral and Maxillofacial Radiology 2013 Imaging Science in Dentistry Vol.43 No.4

Purpose: Demirjian's dental maturity scores and curves have been widely used for human age determination. Several authors have reported considerable differences between the true and estimated age based on the Demirjian curves, which have been accounted for by ethnicity. The purpose of the current study was to assess the role of ethnicity-specific dental maturation curves in age estimation of Saudi children. Materials and Methods: A sample of 452 healthy Saudi children aged 4 to 14 years were aged based on the original French-Canadian Demirjian curves and several modified Demirjian curves specified for certain ethnic groups: Saudi, Kuwaiti, Polish, Dutch, Pakistani, and Belgian. One-way ANOVA and a post hoc Scheff$\acute{e}$'s test were used to assess the differences between chronological age and dental age estimated by the different curves (P<0.05). Results: The curves designed for Dutch, Polish, Saudi, and Belgian (5th percentile) populations had a significantly lower error in estimating age than the original French-Canadian and Belgian (50th percentile) curves. The optimal curve for males was the Saudi one, with a mean absolute difference between estimated age and chronological age of 8.6 months. For females, the optimal curve was the Polish one, with a mean absolute difference of 7.4 months. It was revealed that accurate age determination was not related to certain ethnicity-specific curves. Conclusion: We conclude that ethnicity might play a role in age determination, but not a principal one.

Injective Modules over Prüfer v-Multiplication Domains

Baghdadi, Said El,Kim, Hwankoo,Wang, Fanggui Taylor Francis 2014 Communications in Algebra Vol.42 No.1

Investigation on Stiffness of Finished Stretch Plain Knitted Fabrics Using Fuzzy Decision Trees and Artificial Neural Networks

Rania Baghdadi,Hamza Alibi,Faten Fayala,Xianyi Zeng 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

Stiffness is one of the most important utility properties of textile materials and plays a significant role in well-beingdue to its influence on physiological comfort [1]. On that point are a great deal of structural properties of textile materials alsooperating parameters (knitting+finishing) influencing stiffness and there are also statistically significant interactions betweenthe principal factors determining the stiffness of textile materials. As part of our research, we proposed to facilitate theindustry adjust the most relevant operating parameters before actual manufacturing to reach the desired stiffness and satisfyconsumers. It warrants the application of artificial neural nets (ANNs) to predict the stiffness of finished knitted fabrics andthe utilization of the Fuzzy Decision Tree in the selection procedure, to puzzle out the problem of insufficient data and boildown the complexity of predictive models. Moreover, a virtual leave one out approach dealing with overfitting phenomenonand allowing the selection of the optimal neural network architecture was applied.

Malachite green removal from aqueous solutions using fibrous cellulose sulfate prepared from medical cotton waste: Comprehensive batch and column studies

Majid Baghdadi,Bahram Alipour Soltani,Mohammad Nourani 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.55 No.-

In this study, high capacity and regenerable fibrous cellulose sulfate was prepared by chemical modification of medical cotton waste and its performance was evaluated for malachite green removal through batch and fixed-bed experiments. Equilibrium was achieved after 30 min of mixing (t90%: 3.5 min at 200 mg L1). The equilibrium and kinetic data were fitted to Redlich–Peterson and Dubinin– Radushkevich models (qm: 960 mg g1) and pseudo-second-order model, respectively. Breakthrough data were predicted by Thomas model. The breakthrough volume was increased by increasing flow rate due to decrease in mass transfer resistance. Adsorbent was regenerated using NaCl solution (4% w/v).

Assessing the Performance of Offshore Firms in Tunisia

Leila Baghdadi,Sonia Ben Kheder,Hassen Arouri 세종대학교 경제통합연구소 2019 Journal of Economic Integration Vol.34 No.2

This paper examines the performance of offshore firms in Tunisia for the period 2002~2014. Using firm-level data, we analyze the impact of offshoring on turnover, productivity, wages and firm survival. Overall, offshore firms perform better with respect to all of these indicators. However, in the specific case of offshore firms that export and import at the same time, called two-way offshoring, performance is weaker across the board compared to their onshore counterparts. Lower productivity of offshore firms engaged in both exporting and importing suggests that these firms are low performers and that they self-select the offshore regime to reduce their fixed costs associated with exporting. The survival analysis highlights an increased probability that these types of firms will exit the market once tariffs and tax exemption privileges end, usually after 10 years. Thus, incentives provided in the Tunisian Investment Code are primarily attracting firms in the lower rungs of global value chains.

The Effects of Temporary Immigration on Prices of Non Traded Goods and Services

( Leila Baghdadi ),( Marion Jansen ) 세종대학교 경제통합연구소 (구 세종대학교 국제경제연구소) 2010 Journal of Economic Integration Vol.25 No.4

This paper analyzes the impact of temporary immigration on the prices of nontradable goods and services. It presents a model of a small open economy that produces two goods/services, one tradable and one non tradable. It is assumed that temporary immigrants are confined to work in the non-traded sector and that they are only imperfect substitutes for permanent immigrants and native low skill workers. In our theoretical set-up temporary immigration is predicted to have a negative effect on the prices of non-traded goods and services, while the effect of permanent immigrants depends on the relative low skill domestic labor intensity of the non tradable sector. We test these predictions empirically using a panel dataset of 14 U.S. cities for the period 2000-2006. In line with other recent empirical studies we find that both types of immigration have a negative impact on the relative price of non-tradable services as a whole. These findings confirm that immigration, like trade and offshoring, has the potential to increase welfare through the reduction of consumer and input prices. When distinguishing individual non tradable sectors, though, we find evidence that permanent immigration increases the price of transport and health services. This finding is in line with the predictions of earlier theoretical work and suggests in the context of our model that these sectors are less low skill domestic labor intensive than tradable goods and services.

Pectin purification from plant materials

Fatemeh Baghdadi,Kooshan Nayebzadeh,Mehrnaz Aminifar,Amir Mohammad Mortazavian 한국고분자학회 2023 Macromolecular Research Vol.31 No.8

Pectin, an intricate anionic polysaccharide, is found in the middle lamella of higher plants’ cell walls. It is employed as a gelling agent, thickener, stabilizer, and dietary fiber due to its unique properties. To obtain this carbohydrate polysaccharide, it must be extracted from its sources, namely different parts of fruits and vegetables, in various ways. After the extraction process, owing to the presence of other cell wall constituents such as cellulose microfibrils, hemicellulosic materials, starches, and lignin in the crude aqueous extract, varying methods are used to purify pectin. These methods are predominantly based on the disruption of pectins and solvent molecules interactions (e.g., alcohol precipitation or drying) as well as the complex formation of anionic pectins and cationic materials (e.g., pectin–protein and pectin–metal complexes). Each purification method leads to obtaining pectins with distinctive chemical configurations and characteristics due to the difference in their separation mechanisms. These differences can be in terms of the amounts of sugar contents, galacturonic acid, degree of methylation, the size of isolated pectic fractions, and so forth. Each method has some advantages and disadvantages, and the selection of each method should be based on the costs, needs, and characteristics of the desired pectin.

An experimental and numerical analysis of concrete walls exposed to fire

Mohamed Baghdadi,Mohamed S. Dimia,Mohamed Guenfoud,Abdelhamid Bouchair 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.6

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000°C with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400°C.

Assessing the Performance of Offshore Firms in Tunisia

Leila Baghdadi,Sonia Ben Kheder,Hassen Arouri 세종대학교 경제통합연구소 2019 Journal of Economic Integration Vol.34 No.1

This paper examines the performance of offshore firms in Tunisia for the period 2002~2014. Using firm-level data, we analyze the impact of offshoring on turnover, productivity, wages and firm survival. Overall, offshore firms perform better with respect to all of these indicators. However, in the specific case of offshore firms that export and import at the same time, called two-way offshoring, performance is weaker across the board compared to their onshore counterparts. Lower productivity of offshore firms engaged in both exporting and importing suggests that these firms are low performers and that they self-select the offshore regime to reduce their fixed costs associated with exporting. The survival analysis highlights an increased probability that these types of firms will exit the market once tariffs and tax exemption privileges end, usually after 10 years. Thus, incentives provided in the Tunisian Investment Code are primarily attracting firms in the lower rungs of global value chains.