Surface Runoff and Drought Assessment Using Global Water Resources Datasets - from Oum Er Rbia Basin to the Moroccan Country Scale

Water Resources Management - Precipitation and surface runoff vary strongly in space and time across Morocco. The country’s water management is primarily governed at the basin level,...     

Impact of Hydrogen Passivation on Electrical Properties of Polysilicon Thin Films

Silicon - The effect of hydrogen passivation and heat treatments on the electronic activity at grain boundaries in thin films of polysilicon deposited by LP-CVD (Low Pressure Chemical Vapor...     

Screening of four vascular aquatic plants for uptake of monosodium methanearsonate (MSMA)

The post-emergent herbicide, MSMA, is used extensively for weed control in non-edible crops and for chemical mowing along roadside rights-of-way. Herbicide may gain access to adjacent water bodies by accidental application or by runoff from sprayed plots. This study utilized floating and rooted plant species in hydroponic solution to monitor the uptake of trace levels of the herbicide from an aqueous concentration of 24 μg/ml. Plant species evaluated included Eichhornia crassipes, Alternanthera philoxeroides, Hydrophila lacustris and Lemna minor. Plants were analyzed for total arsenic over the 6 weeks of study using the silver diethyldithiocarbamate (SDDC) procedure. Bioaccumulation ratios were then determined for each plant species.     

Application of GIS-based statistical modeling for landslide susceptibility mapping in the city of Azazga,Northern Algeria

Landslide susceptibility mapping is a necessary tool in order to manage the landslides hazard and improve the risk mitigation. In this research, we validate and compare the landslide susceptibility maps (LSMs) produced by applying four geographic information system (GIS)-based statistical approaches including frequency ratio (FR), statistical index (SI), weights of evidence (WoE), and logistic regression (LR) for the urban area of Azazga. For this purpose, firstly, a landslide inventory map was prepared from aerial photographs and high-resolution satellite imagery interpretation, and detailed fieldwork. Seventy percent of the mapped landslides were selected for landslide susceptibility modeling, and the remaining (30%) were used for model validation. Secondly, ten landslide factors including the slope, aspect, altitude, land use, lithology, precipitation, distance to drainage, distance to faults, distance to lineaments, and distance to roads have been derived from high-resolution Alsat 2A satellite images, aerial photographs, geological map, DEM, and rainfall database. Thirdly, we established LSMs by evaluating the relationships between the detected landslide locations and the ten landslides factors using FR, SI, LR, and WoE models in GIS. Finally, the obtained LSMs of the four models have been validated using the receiver operating characteristics curves (ROCs). The validation process indicated that the FR method provided more accurate prediction (78.4%) in generating LSMs than the SI (78.1%),WoE (73.5%), and LR (72.1%) models. The results revealed also that all the used statistical models provided good accuracy in landslide susceptibility mapping.

     

Effect of the tank geometry on the storage and destocking of hydrogen on metal hydride (LaNi5H2)

The present numerical study aimed at studying the solid-statehydrogen storage and destocking in the LanthanumNickel (LaNi₅H₂) in a concentric triple-tube heat exchanger. Moreover, the influence of the thermal-reactor geometry for the storage and destocking hydrogen have been examined by changing the diameters of the heat exchanger. The performance of LanthanumNickel was compared with those of the hydride (MmNi₄.₆Fe₀.₄) and activated carbon. The flowing parameters: kinetics of hydrogen absorption/desorption, chemical reactions, enthalpy of fusion, equilibrium pressure, hydrogen concentration and the storage capacity were considered for calculating the terms of mass and energy equations. The hydride thermal and mass behaviour was integrated in the CFD Fluent with software (C++). A good agreement between the presented model and the literature experimental results was obtained. Additionally, the mentioned above parameters have shown a significant impact on the geometry of the reactor.     

An integrated optimisation for the weight,the structural performance and the cost of composite structures

An integrated optimisation methodology is proposed to optimise the manufacturing cost as well as the structural performance and the weight of composite laminated plates manufactured by the resin transfer moulding (RTM) process. In the present approach, the fibre type, the number of fabrics, the layer stacking sequence and the fibre volume fraction are optimised to minimise the structural weight and the material cost of composite structure under the stiffness constraint and the mould filling time constraint which is a part of process cycle time. With the results obtained, it is investigated how the weight and the material cost are traded-off. The optimisation methodology suggests a guide to cost-effective material selection in the preliminary conceptual design stage.     

String Matching Over Compressed Text on Handheld Devices Using Tagged Sub-Optimal Code (TSC)

This paper presents Tagged Sub-optimal code (TSC), a new coding technique to speed up string matching over compressed databases on personal digital assistants (PDA). TSC is a variable-length sub-optimal code that supports minimal prefix property. It always determines its codeword boundary without traversing a tree or lookup table. TSC technique may be beneficial in many types of applications: speeding up string matching over compressed text, and speeding decoding process. This paper also presents two algorithms for string matching over compressed text using TSC (SCTT) and the Byte Pair Encoding (BPE) technique (SCTB). indent Several experiments were conducted to compare the performance of TSC, Byte Pair Encoding (BPE), and Huffman code. Several PDA databases with different record sizes were used: the well-known Calgary dataset and a set of small-sized PDA databases. Experimental results show that SCTT is almost twice as fast as the Huffman-based algorithm. SCTT has also the same performance in search time as the search in uncompressed databases and is faster than the SCTB algorithm. For frequently updated PDA databases such as phone books, to-do list, and memos, SCTT is the recommended method regardless of the size of the average record length, since the time required to compress the updated records using BPE poses significant delays compared to TSC.Abdeghani Bellaachia is an associate professor at the Computer Science Department, George Washington University. He received his Diploma of Engineering from Mohammadia School of Engineering in Rabat, Morocco, in 1983, the MS and Doctoral of Science degrees from the George Washington University in 1992. He was the chief architect of the Arabization of the Palm-OS platform. His research interests include data mining, multi-lingual information retrieval systems, cross-language retrieval systems, database management systems, bio-informatics, design and analysis of algorithms, handheld computing, and parallel processing.Iehab AL Rassan works for Ministry of higher education in Saudi Arabia, director of information technology department. He received his B.A. in Computer Information Systems from King Faisal University. He then received his M.S. in Computer Science from Fairleigh Dickinson University and his Doctor of Science in Computer Science from the George Washington University. His research interests include coding theories, information retrieval, string-matching algorithms, data compression, and handheld computing.     

Hybrid one-class classifier ensemble based on fuzzy integral for open-lexicon handwritten Arabic word recognition

Pattern Analysis and Applications - One-class classifier (OCC) is involved for solving different kinds of problems due to its ability to represent a class distribution regardless the remaining...     

Interfacial charge transfer and photocatalytic activity in a reverse designed Bi2O3/TiO2 core-shell

In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO₂ and Bi₂O₃ layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO₂ anatase and Bi₂O₃ layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi₂O₃ collects holes from TiO₂, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H₂ generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity.