Physicochemical characterization and adsorptive properties of some Moroccan clay minerals extruded as lab-scale monoliths

Textural, structural and adsorptive properties of some Moroccan clays were investigated. The minerals were used as raw material for extrusion of honeycomb monoliths. Adsorption and desorption tests were performed with selected model pollutants such as volatile organic compounds (VOCs). The clays have been chosen, apart from their abundance and price, on the basis of successful extrusion as integral lab-scale honeycomb monoliths. The obtained monoliths have been subjected to measurements of the mechanical strength.     

An online approach for multi-sprite generation based on camera parameters estimation

We propose in this work to synthesize online the visual content of a complex video into multiple sprites, while detecting on-the-fly each sprite’s limits. For each received frame, physically meaningful camera rotation angles and focal lengths are firstly estimated from frame-to-sprite homography. These physical parameters are then used by a thresholding-based assignment stage to confirm whether the frame can be added without distortions on one of the sprites that have been built up to that instant. In this case, the selected sprite will be updated online accordingly by applying direct frame-to-sprite warping and advanced median blending of only the newly discovered background content. Else, a new sprite must be defined while selecting the current frame as a reference frame. Extensive experiments accomplished on challenging videos demonstrate that the proposed approach can process online a long video while preventing accumulation of alignment errors.     

A consistent QoS routing strategy for video streaming services in SDN networks

The software‐defined networking (SDN) paradigm proposes to decouple the control plane (decision‐making process) and the data plane (packet forwarding) to overcome the limitations of traditional network infrastructures, which are known to be difficult to manage, especially at scale. Although there are previous works focusing on the problem of quality of service (QoS) routing in SDN networks, only few solutions have taken into consideration the network consistency, which reflects the adequacy between the decisions made and the decisions that should be taken. Therefore, we propose a network architecture that guarantees the consistency of the decisions to be taken in an SDN network. A consistent QoS routing strategy is then introduced in a way that avoids any quality degradation of prioritized traffic while optimizing resources usage. Thus, we proposed a traffic dispersion heuristic in order to achieve this goal. We compared our approach with several existing framework in terms of best‐effort flows average throughput, average video bitrate, and video quality of experience (QoE). The emulation results, which are performed using the Mininet environment, clearly demonstrate the effectiveness of the proposed approach that outperforms existing frameworks.     

Optimization of cyclopropane fatty acids production in Yarrowia lipolytica

Cyclopropane fatty acids, which can be simply converted to methylated fatty acids, are good unusual fatty acid candidates for long-term resistance to oxidization and low-temperature fluidity useful for oleochemistry and biofuels. Cyclopropane fatty acids are present in low amounts in plants or bacteria. In order to develop a process for large-scale biolipid production, we expressed 10 cyclopropane fatty acid synthases from various organisms in the oleaginous yeast Yarrowia lipolytica, a model yeast for lipid metabolism and naturally capable of producing large amounts of lipids. The Escherichia coli cyclopropane fatty acid synthase expression in Y. lipolytica allows the production of two classes of cyclopropane fatty acids, a C17:0 cyclopropanated form and a C19:0 cyclopropanated form, whereas others produce only the C17:0 form. Expression optimization and fed-batch fermentation set-up enable us to reach a specific productivity of 0.032 g·L⁻¹·hr⁻¹ with a genetically modified strain containing cyclopropane fatty acid up to 45% of the total lipid content corresponding to a titre of 2.3 ± 0.2 g/L and a yield of 56.2 ± 4.4 mg/g.     

Melting of nano-enhanced phase change material in a cavity heated sinusoidal from below: Numerical study using lattice Boltzmann method

Natural convection and melting of ice as a phase change material dispersed with copper nanoparticles are numerically investigated. Square cavity filled with nano-mixture (Cu−ice) subjected to sinusoidal temperature distributions from the hot bottom boundary. The phase change process and heat transfer are formulated and solved using the enthalpy-based lattice Boltzmann method. Home-built numerical code is developed and validated. The effect of Rayleigh number (Ra = 10⁴, 10⁵, and 10⁶) and copper nanoparticle concentration (ϕ = 0%, 1%, 3%, and 5%) on the flow characteristics and thermal performance of NePCM during the melting process is examined. According to the numerical results, the melting and charging times decrease by increasing the Rayleigh number. It is also observed that increasing the volume fraction of nanoparticle decrease melting time by up to 10%.     

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.     

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.     

IR spectroscopy study of polypropylene natural aging

Structural modifications of a commercial polypropylene (PP) sample are studied by IR spectroscopy. Aging this sample under an ambient atmosphere with or without the presence of ambient light shows the oxidation process to be the most predominant. Spectral analysis reveals that the commercial sample is isotactic and also indicates that, for the new sample, oxygen establishes single bonds with carbon. However, through the aging process, spectral changes essentially occur in the regions of ∼3400, ∼1712, and 1170 cm⁻¹ which correspond to hydroxyl and/or hydroperoxide groups, a carbonyl group, and C O, respectively. The deconvolution of the bands corresponding to a carbonyl group reveals the presence of a complicated mixture of oxidation products: aldehydes, ketones, esters, acids, peresters, and peracids. Spectral analysis also shows that the most favorable site for oxidation is at the methylene group. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1742–1748, 2000     

An evidential fusion approach for activity recognition in ambient intelligence environments

With the growing emergence of ambient intelligence, ubiquitous computing, sensor networks and wireless networking technologies, “ubiquitous networked robotics” is becoming an active research domain of intelligent autonomous systems. It targets new innovative applications in which robotic systems will become part of these networks of artifacts to provide novel capabilities and various assistive services anywhere and anytime, such as healthcare and monitoring services for elderly in Ambient Assisted Living (AAL) environments. Situation recognition, in general, and activity recognition, in particular, provide an added value on the contextual information that can help the ubiquitous networked robot to autonomously provide the best service that meet the needs of the elderly. Dempster–Shafer theory of evidence and its derivatives are an efficient tool to handle uncertainty and incompleteness in smart homes and ubiquitous computing environments. However, their combination rules yield counter-intuitive results in high conflicting activities. In this paper, we propose a new approach to support conflict resolution in activity recognition in AAL environments. This approach is based on a new mapping for conflict evidential fusion to increase the efficiency and accuracy of activity recognition. It gives intuitive interpretation for combining multiple sources in all conflicting situations. The proposed approach, evaluated on a real world smart home dataset, achieves 78% of accuracy in activity recognition. The obtained results outperform those obtained with the existing combination rules.