Search

The recycling of paper mill sludges is increasing rapidly as far as the economical and positive environmental benefits are realised. The aim of the present work was to show if paper mill sludges could be used as a partial replacement of Portland cement in mortar without affecting their durability. Calcined at temperatures between 650°C and 800°C, the pozzolanic activity of ashes from paper mill sludges is improved because of the transformation of kaolinite in metakaolin. The mechanical characteristics of mortar containing 25% of these ashes appear comparable to standard mortar (containing 100% of Portland cement). The nature of the leaching does not affect the mechanical strength of mortars leached during 64 days. However, there is also a loss of compressive strength of mortars. [ABSTRACT FROM AUTHOR]

The Atlas cedar (Cedrus atlantica) is an emblematic species of Morocco, classified by the International Union for the Conservation of Nature (IUCN) in the red list of endangered species. Determining its potential area under current climatic conditions is an essential step in planning and ensuring its conservation. In this paper, we applied the maximum-entropy algorithm (MaxEnt) to predict the current and potential distribution of the Atlas cedar in order to provide a basis for its conservation. The adjusted model had an excellent predictive quality (AUC = 0.967). The most significant variables influencing the distribution of Atlas cedar, under current climatic conditions, are the precipitation in the driest quarter, precipitation in the driest month, average annual temperature and relative humidity. The model developed made it possible to establish the first map of the suitable potential area of the Atlas cedar in Morocco. The results obtained will guide managers to identify favorable sites for the rehabilitation of the Atlas cedar threatened with extinction. [ABSTRACT FROM AUTHOR]

During an epidemic/pandemic caused by an unknown virus such as SRAS-CoV-2, the aetiological agent of COVID-19, health practitioners cannot predict the behavior of the virus and therefore the course of the disease. They also cannot predict how patients will react to different treatments. In this paper, authors propose a distributed system's architecture for predicting the course of the disease and patient reactions for treatments, using real-time data of patients with the same disease from all over the world. The system uses geographic and the "Patient, Intervention, Comparison, Outcome/s" (PICO) questions classification of patients. It shares information with inspiration from peer-to-peer download model and uses a semantic model to save and compare clinical questions. The system also proposes to generate personalized self-tests that can be made available to the population to reduce the panic caused by the epidemic. The operation of the system is illustrated by an example of a patient with COVID-19. [ABSTRACT FROM AUTHOR]

Since the last decades, transhumance movements in the province of Ifrane are reduced in favor of a general progress of sedentarisation on high altitude rangelands. This permanent installation induces overexploitation of high-altitude rangelands and forests essentially composed of green oak and the Atlas cedar trees. The aim of this paper is first to quantify the evolution of sedentarisation on high-altitude rangelands through the evolution of construction' numbers, then to highlight the main factors inducing this phenomenon and finally to show the impacts of this progression on forest resources. The methodology adopted is based on data collected through semi-structured interviews; with groups of resource persons from all ethnic communities of the province. The results show an evolution of the sedentarisation of 24 new constructions per year between 2005 and 2015. This evolution took place under the effect of internal factors (demographic growth, cultivation of the low altitude rangelands, etc.) and external factors (installation of Adarouch Ranch and disengagement of the State from its enforcement role). Sedentarization is a threat to the sustainability of forest resources through the continuous exploitation in time and space of these resources, the abandonment of the practice of Agdal on the lawns and the generalization of delimbing and topping of forest trees in times of scarcity (autumn-- winter). [ABSTRACT FROM AUTHOR]

The management of Solid Waste is at the center of national and international debates because the urban environment in particular undergoes, in recent decades, a regression due to the technological advances and the change in lifestyle. The development achieved is accompanied by a continuous increase in the Urban Sustainable Residues generated by human activities. In this regard, the environment is nowadays a major concern of the public authorities through the establishment of panoply of regulatory texts and the creation of institutions with the aim of preserving public health and sustainable urban development. In Annaba, a city in Northeastern of Algeria, demographic and urban growth has generated varied solid residues in quantity and quality potentially harmful that must be taken care of. The latter affect not only the environmental indicators (water, air and soil) but also the living conditions in the city. This paper explores the production, composition and management system of the Solid Waste in the city of Annaba. There treatment seems inefficient and requires a continuous improvement via a local strategy based on awareness, training and greater involvement of the citizen and stakeholders. The method of treating Solid Urban Residues through composting and recycling remains a shortfall. [ABSTRACT FROM AUTHOR]

In this paper, an analytical solution is presented for vibration behaviour analysis of functionally graded materials plates (FGM). During manufacture of these plates, defects such as porosities can appear. Those can change the entire behaviour of these plates. A method based on a higher shear deformation theory will be presented to study the free vibration of FGM plates resting on elastic foundation. Two different porosity distributions through thickness direction of plate will be retained. The elasticity moduli and mass density of these plates are assumed to be graded in the thickness direction according two distribution patterns. The governing equations are obtained through the Hamilton's principal and the closed form solutions in terms of natural frequencies are obtained by using Navier technique. The numerical results obtained through the present analysis are compared with the ones available in the literature, and a parametric study is carried out to investigate the influence of the varying porosity distributions on the vibration response of FGM plates resting on elastic foundation. [ABSTRACT FROM AUTHOR]

Urban reality of our urban fabric is facing serious problems since independence, led mainly by inadequate urban forms, not respecting the climatic conditions of the home base. So, those problems have altered the urban ecosystem and lead to uncomfortable urban spaces. However, the old forms were able to adapt the local climatic conditions and giving more adequate urban solutions. The purpose of this paper is to be aware of the influence of the antique building complexes shape and the new one to create a favourable microclimate for the appropriation of outdoor spaces. For an evaluation approach that involves the use of an experimental method within the competence of ENVI-met3.1 software, the study demonstrated that the old tissues exhibit compact building complexes are more adapted to semi-arid climate of Constantine then those of building complexes exploded. [ABSTRACT FROM AUTHOR]

Le traitement des déchets représente un coût non négligeable pour toutes les municipalités. La ville de Mohammedia comme toute autre ville n'échappe pas à ce sort. 2,72 millions d'euros ont été dépensé pour la collecte et le traitement de 78608 tonnes de déchets ménagers et assimilés produits en 2013. Ceci représente une production journalière de 0,807 kg par habitant. La Commune urbaine de Mohammedia vise à réduire sa production en déchets sur son territoire et ce à travers : la mise en place d'un tri sélectif en amont et la valorisation par compostage ou bio-méthanisation des matières organiques et fermentescibles. La présente étude a permis de faire une caractérisation de la production des déchets ménagers. Une connaissance du gisement et de la composition des déchets assimilables aux ordures ménagères produits est un élément clef qui a pour but de déterminer : la quantité des déchets produite, la part recyclable et sa composition par catégories de déchets, la part de matières organiques et fermentescible, la part de matières non recyclables, le coût d'élimination de ces déchets et le coût de valorisation de ces matières. Par ailleurs, une quantité de 540 à 740 kg a été trié pour chaque type d'habitat de la ville, selon 13 composantes des déchets ménagers. Ceci a montré que les ordures ménagères de la ville de Mohammedia contiennent plus de 44,36 % de déchets organiques entièrement valorisables par des simples procédés, 29,46 % de matériaux valorisables directement par recyclage (Verre, plastique, papier / carton, et métaux), et 18,67 % des substances valorisables mais qui nécessitent des investissements importants. The treatment of waste represents a significant cost for all municipalities. The city of Mohammedia like others cities cannot escape this fate. 2,72 million euros were spent collecting and processing 78608 tones of household waste and related products in 2013. This represents a daily production of 0,807 kg per person. The Urban Commune of Mohammedia aims to reduce waste production in its territory and this will be done through the establishment of a selective upstream of waste and the recovery by composting or bio-methanation of organic and fermentable waste. The study helped to characterize the production of the household and similar waste. Knowledge of the deposit and the composition of the waste assimilated to domestic waste is a key element of this study to determine: the amount of waste produced the composition share and recyclable waste categories, the share of organic and fermentable waste, the share of non-recyclable materials, the cost of waste disposal and the cost of recovery of such materials. In addition, an amount of 540 to 740 kg was sorted for each habitat type in the city, according to 13 components of household waste, which showed that the garbage of the city of Mohammedia contains more than 44.36% of fully recyclable organic waste by simple methods, 29.46% directly recyclable components (glass, plastic, paper / cardboard, and metals), and 18.67% of recyclable substances which require substantial investments. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study a bioclimatic house using solar energy which must guarantee the feeling of comfort for its occupants. It is located at Souidani west of Algiers (Algeria). This prototype is tested in order to obtain good energy efficiency to enable energy savings. The work presented in the Algerian climatic conditions, is a heating and cooling system of a house by reversible underfloor. The technique is used in order to ensure a comfortable climate throughout the year. We proceed to the numerical simulation of the thermal behavior of the indoor environments of the house considered, using the Fluent software. The results show that the reversible underfloor heaters all the rooms of the habitat, homogeneously, and also contributes to its cooling in summer. This system provides thermal comfort superior to other conventional systems. [ABSTRACT FROM AUTHOR]

In this paper API 5L X70 steel is characterize experimentally by mechanical tests. Tension tests, microstructure, hardness and resilience and finally bending tests are performed. A finite element validation study using ANSYS calculation code is presented in the case of bending in order to validate the constitutive equation. [ABSTRACT FROM AUTHOR]

We present in this paper, the results obtained from analyzes, performed on methanolic extracts of Myrtus communis L, collected in situ, and methanolic extracts prepared from a callus tissue culture of this plant, propagated in vitro. Several spectrophotometric assays were performed on these extracts. The plant extract obtained in situ was richer in polyphenols than the extract prepared from calli. It expressed also good free radical scavenging activity with EC50=0,69mg/ml, and a very good inhibitory potency of linoleic acid peroxidation estimated at 87,45%, which is much higher than the ascorbic acid used as positive control (50,57%). However, methanolic extracts prepared from calli expressed the best chelating Fe2+ ions estimated at 73,13%. [ABSTRACT FROM AUTHOR]

In this paper, we present the results concerning the design, the realization and the characterization of a photovoltaic system (PV), medium power (100 W), equipped with a MPPT control, a controller battery, a system for tracking the sun and a system for the acquisition and supervision, based on a microcontroller. The experiment of each block, show that: (1) The digital MPPT control convergence instantly operating point of the PV panels around the maximum power point, independently of rapid changes in the illumination and the load, (2) Regulating the charging and discharging of batteries is carried using an algorithm including the specificities of the PV system, (3) The need for a sun tracker to increase the power supplied by the PV panels. All the results show the reliability of a complete PV system and an operation exploiting the maximum of solar energy. [ABSTRACT FROM AUTHOR]

Kenaf (Hibiscus cannabinus L.) is an annual fiber plant of Malvacea family. The stem produces two types of fiber, a coarser fiber in the outer layer and a finer fiber in the core. It has been cultivated for the manufactures of ropes, textiles, paper and insulation and used in many industries including automobile industry. Problems encountered in the establishment of uniform, vigorously growing kenaf result from seed quality. For mass production kenaf, in vitro propagation tests were carried out starting from 1 cm microcuttings of "Tainung 2", variety. Growth hormones were added at various doses to culture medium Murashige and Skoog (1962) (MS) in order to determine the most favorable culture medium for growth and development of the explants during different phases. Results showed a difference in response of explants to media tested. For initiation and propagation, the most favorable is (MS) without hormones for recovery of vegetation in vitro explants of kenaf and produce 3,8 nodes per explants per month. Rooting was strongly favored by the addition to the medium of MS 0,25 mg.l-1 IBA and 25 mg.l-1 of β- cyclodextrin, which cause the formation of 9,22 roots per vitroplant and an average length of 1,9 cm. The rooted shoots are acclimated to stifle in a greenhouse with a success rate of 100%. [ABSTRACT FROM AUTHOR]

In this paper, an elastic, rectangular, and simply supported, power-law functionally graded material (P-FGM) beam of thick thickness subjected to uniformly distributed transverse loading has been investigated. The P-FGM system consists of ceramic (ZrO2) and metal (Ti-6Al-4V) phases varying through the thickness of beam. Major classes of representative theories such as classical laminate beam theory (CLBT), first-order shear deformation theory (FSDBT) and high-order theories (TSDBT), (SSDBT) and (ESDBT). The Poisson's ratio of the thick P-FGM beam is assumed to be constant, but their Young's moduli vary continuously throughout the thickness direction according to the volume fraction of constituents defined by power-law function. The analytical solution of the rectangular beams in P-FGM subjected to the inflection is obtained, by using the approach of Navier. Qualitative and quantitative assessments of displacement and stress fields have been presented and discussed. [ABSTRACT FROM AUTHOR]

This paper studies the geochemical evolution of the soil solution in contact with water irrigation of a positive residual Alkalinity, in order to predict their salinization path and structural degradation under the effect of water concentration by evaporation. Two soil textures, one equilibrated (S1) and the other is clay (S2), are distributed in pots made by PVC tubes of 5 cm diameter and 12 cm high in the laboratory. The water with a positive residual alkalinity (E: RSC> 0) is brought up to pots till soil is oversaturated then, after 24 hours, the water excess is shipping dry naturally and the soil reaches his retention capacity. The weight difference between the wet pot and the dry one gives the necessary water volume to push the soil into his field capacity. The total evaporation of the brought volume water is the concentration factor (CF). Soil solution contained in the pots is extracted for chemical analysis. Fifteen concentration factors were performed. As far as the waters are concentrated, the calcium and magnesium ions were precipitates and an increase in the sodium molality in the soil solution. The increase of the concentrations factors leads to the desorption of sodium ion to the exchange complex under the effect of depletion of elements with big solubility's (Ca and Mg). It was thus observed an increase in the SAR, especially for clayey soils, which led to the destruction of the structure. [ABSTRACT FROM AUTHOR]

In the deformation analysis of geodetic networks, there are two conventional methods for estimating movement of an area of study: displacement vectors and strain tensors. However, the evaluation and representation of the deformation depend on the priori reference system and the configuration of chosen figures that constitute the entire network. These constraints make difficult the interpretation of the results. Through this present paper, a solution based on the finite element method (FEM) is proposed to refine the estimation and the representation of the deformation of geodetic networks. In this context, a study of the deformation is carried out to analyze the horizontal motion of the geodetic network Cheliff observed by classical triangulation in 1976 (by INCT) and 1981 (by CRAAG), based on a twodimensional elastic finite element model. The different results are illustrated in terms of displacement vectors, strain tensors and stress tensors. Deformation of the area thus determined is interpreted according to previous geophysical studies. In addition, different results revealed the following phenomena: A phenomenon of compressive of Cheliff area, in the NNW-SSE orientation, due to the rapprochement of the African and Eurasian tectonic plates that caused the fault opposite the famous earthquake of 10 October 1980. A phenomenon of block rotation in the SE and NW parts of the fault, in a retrograde direction. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the influence of drying temperature on the active ingredients of medicinal plants: the case of total alkaloids of Alstonia boonei Wild. Barks of Alstonia boonei, collected on one stem, were cut and dried in the fresh air, and in an electric dryer at 40 ° C, 50 ° C and 60 ° C. Samples from the several drying methods and others of a fresh bark were then subjected to a phytochemical analysis in order to do a quantitative and qualitative study of alkaloids contained in barks. The study revealed that the alkaloid content of the bark of Alstonia boonei decreases when the drying temperature increases. The decay rate of the extraction yield of total alkaloids compared to the samples is 0.00091% for an increase of one degree Celsius. Thus, the extraction yield of total alkaloids is 0.0436% for the fresh sample, 0.0430% for drying at open air and 0.0174% for a drying temperature at 60 ° C. Natural drying of bark at the fresh air or at room temperature limit the losses of alkaloids. [ABSTRACT FROM AUTHOR]