Extraction and characterization of Retama monosperma fibers

The aims of this study were to determine the good conditions for fibers extraction from Retama monosperma leaves and their mechanical, physical and chemical characteristics. The fibers were extracted using a range of NaOH concentration from 1 to 16% in a period of treatment of 1 to 24 h, coupled with a physical treatment. For the evaluation of physico-mechanical characteristics, 200 samples were performed in the tensile test. The biochemical composition of the fibers was determined after separation of the parietal compounds. The results show that the best fiber yield was 11.51% obtained by a treatment of 14% NaOH for 8 h, followed by a physical treatment. The fibers biocomposition was 87.3% of cellulose, 7.5% of hemicelluloses and 1% of lignin. The Young's modulus was 13.3 GPa, tensile strength was 110 MPa and density was 1.3 g/cm3. The average fiber length was 155.7 mm. The fibers yield and characteristics showed that R. monosperma plant may in future be suitable source for natural fibers.Key words: Retama monosperma young stems, fibers, extraction, characterization

Comparison and Evaluation of Deadlock Prevention Methods for Different Size Automated Manufacturing Systems

In automated manufacturing systems (AMSs), deadlocks problems can arise due to limited shared resources. Petri nets are an effective tool to prevent deadlocks in AMSs. In this paper, a simulation based on existing deadlock prevention policies and different Petri net models are considered to explore whether a permissive liveness-enforcing Petri net supervisor can provide better time performance. The work of simulation is implemented as follows. (1) Assign the time to the controlled Petri net models, which leads to timed Petri nets. (2) Build the Petri net model using MATLAB software. (3) Run and simulate the model, and simulation results are analyzed to determine which existing policies are suitable for different systems. Siphons and iterative methods are used for deadlocks prevention. Finally, the computational results show that the selected deadlock policies may not imply high resource utilization and plant productivity, which have been shown theoretically in previous publications. However, for all selected AMSs, the iterative methods always lead to structurally and computationally complex liveness-enforcing net supervisors compared to the siphons methods. Moreover, they can provide better behavioral permissiveness than siphons methods for small systems. For large systems, a strict minimal siphon method leads to better behavioral permissiveness than the other methods

Investigation of Parietal Polysaccharides from Retama raetam Roots

This study characterizes the cell wall hemicellulose and pectins polymers of Retama raetam. This species develops a particularly important root system and is adapted to arid areas. The cellulose, hemicelluloses and pectins were extracted. The cellulose remains the major component of the wall (27% for young roots and 80% for  adult roots), hemicelluloses (14.3% for young roots and 3.6%  for adult roots) and pectins (17.3% for young roots and 4.1% for adult roots). The monosaccharidic composition of water soluble extracts determined by gas liquid chromatography (GLC) and completed by infrared (FTIR) spectroscopy of hemicellulosic shows the presence of xylose as a major monosaccharide in the non-cellulose polysaccharides (47.8% for young roots and 59.5% for adult roots). These results indicate the presence of the homogalacturonans and rhamnogalacturonans in pectin. This study constitutes the preliminary data obtained in the biochemical analysis of the parietal compounds of the roots of a species which grows in an arid area in comparison with those of its aerial parts.Keywords: Retama raetam, Roots, Cell Wall, Investigation, Polysaccharides, Monosaccharidi

Record of the first Pleonexes species (Crustacea: Amphipoda: Ampithoidae) in Moroccan waters: Pleonexes gammaroides Spence Bate, 1857

The ampithoid amphipod crustacean Pleonexes gammaroides Spence Bate, 1857 is reported from Morocco (northeastern Atlantic Ocean) for the first time, where it is the only representative of the genus Pleonexes Spence Bate, 1857 so far. Specimens were collected from the upper fringe of the infralittoral zone (including low intertidal) of El Jadida coastline associated with the holdfasts of the kelp Saccorhiza polyschides (Lightfoot) Batters (Phaeophyceae), colonising the sublittoral fringe in the southernmost distribution limit (Morocco). This finding updates the known geographical distribution of P. gammaroides in northern Africa and northeastern Atlantic. Some ecological and distributional details of this amphipod species are briefly discussed here.National Centre for Scientific and Technical Research (CNRST), Morocco 5UCD2017, AGA- KHAN Foundation under the project MARAFRICA AGA-KHAN/540316524/2019info:eu-repo/semantics/publishedVersio

Origine et datation des eaux souterraines du bassin hydrologique de la lagune d’Oualidia

Le Sahel d’Oualidia fait partie du littoral atlantique. Il borde la lagune d’Oualidia, avec un climat dominant de type semi-aride. Dans cette zone, les aquifères carbonatés de grès calcaire plio-quaternaire et du calcaire de Dridrate (Hauterivien supérieur), sont en relation directe avec l’océan atlantique. Ces aquifères subissent des prélèvements par pompage destinés à l’irrigation de cultures maraîchères et à l’alimentation de la population rurale. Par conséquent, ils sont menacés par des problèmes de surexploitation et de salinisation par intrusion marine. De nombreuses questions sont actuellement posées sur l’importance des ressources souterraines exploitées et sur leur état de salinité. Dans le cadre de cette étude, l’utilisation des isotopes stables 18O et 2H, a permis de mettre en évidence la recharge des aquifères qui se fait par des pluies d’origine atlantique. Les eaux souterraines sont localement affectées par des intrusions d’eau océanique. La datation de certains échantillons par le 14C a permis de révéler des âges anciens. D’autres analyses seront réalisées pour vérifier ces hypothèses.El Sahel de Oualidia se encuentra en el litoral atlántico. Está en el borde de la laguna de Oualidia con un clima predominantemente de tipo semi-árido. En esta zona, los acuíferos carbonatados de las areniscas calcáreas plio-cuaternarias y de la caliza de Dridrate (Hauteriviense superior) están relacionados directamente con el Océano Atlántico. Estos acuíferos están sometidos a descarga por bombeos utilizados para el riego de los cultivos de las marismas y para el abastecimiento de la población rural. Por ello, están amenazados por problemas de sobreexplotación y de salinización por intrusión marina. Se plantean actualmente numerosas cuestiones sobre la importancia de los recursos subterráneos explotados y sobre su estado de salinización. Dentro del marco de este estudio, la utilización de isótopos estables de 18O y 2H permite poner en evidencia la recarga de los acuíferos que se efectúa por las lluvias de origen atlántico. Las aguas subterráneas se ven localmente afectadas por intrusiones de agua oceánica. La datación de algunas muestras por el 14C demuestra la existencia de edades antiguas. Se realizarán otros análisis para verificar estas hipótesis

Studying the Effect of Process Parameters on Part Depth in Single Point Incremental Forming of AA1050-H14 Aluminum Alloy Sheets

Single Point Incremental Forming (SPIF) is an innovative forming approach for sheet metal that promises an inexpensive and flexible way to produce sheet metal parts in small batches. SPIF allows the production of complex geometries using a computer numerical control machine. In this study, SPIF has been conducted to investigate the effects of sheet thickness, tool diameter, feed rate, and step size on part depth. Statistical tools were used to design the experiments. Analysis of variance, as well as regression and optimization techniques were used to analyze the resulting part depth. Two levels of each parameter were included in a full factorial design. The study found several relations amongst the process parameters and the part depth. In summary, it was proved that the sheet thickness and tool diameter have the greatest effect on the part depth, whereas the step size has a small, but significant one

Coverage and Capacity Planning of LTE Network for-Taizz City

This paper is based on the newly advanced cellular technology called Long Term Evolution (LTE). It is intended to give a good understanding of Radio Network planning of LTE and perform a case study onTaizz City, one of the highest populated cities in Yemen with a selected area of about 118.09km2. The LTE Radio network planning involves coverage estimation, capacity evaluation. In this paper the coverage estimation is done with regards to the real environment dataat its nominal stage to obtain better estimations. Propagation modeling is done using COST HATA W/I model with inclusion of additional parameters obtained from the real environment/terrain what improves the coverage estimation.This in turn, results in a wide coverage, introducing high quality services and excellent mobility support. The simulation is performed using Atoll program to evaluate the traffic demand for all services and to calculate the average throughput of each service

Strong consistency rate in functional single index expectile model for spatial data

Analyzing the real impact of spatial dependency in financial time series data is crucial to financial risk management. It has been a challenging issue in the last decade. This is because most financial transactions are performed via the internet and the spatial dependency between different international stock markets is not standard. The present paper investigates functional expectile regression as a spatial financial risk model. Specifically, we construct a nonparametric estimator of this functional model for the functional single index regression (FSIR) structure. The asymptotic properties of this estimator are elaborated over general spatial settings. More precisely, we establish Borel-Cantelli consistency (BCC) of the constructed estimator. The latter is obtained with the precision of the convergence rate. A simulation investigation is performed to show the easy applicability of the constructed estimator in practice. Finally, real data analysis about the financial data (Euro Stoxx-50 index data) is used to illustrate the effectiveness of our methodology

Political Communication

The term "strategic communication" traditionally has been understood as referring to external corporate communication, such as public relations, marketing communication, and advertising, with insufficient consideration beyond its role as a tool of persuasive influence. In recent years, however, the field of strategic communication has evolved to be more holistic in its approach and its role within sociocultural contexts. Articles, textbooks, and handbooks have attempted to define the scope, purpose, and nature of the concept, but as the first major comprehensive work of its kind, The International Encyclopedia of Strategic Communication captures the full scope of contemporary theory and practice in strategic communication.info:eu-repo/semantics/publishedVersio