Simulation of rock salt dissolution and its impact on land subsidence

Extensive land subsidence can occur due to subsurface dissolution of evaporites such as halite and gypsum. This paper explores techniques to simulate the salt dissolution forming an intrastratal karst, which is embedded in a sequence of carbonates, marls, anhydrite and gypsum. A numerical model is developed to simulate laminar flow in a subhorizontal void, which corresponds to an opening intrastratal karst. The numerical model is based on the laminar steady-state Stokes flow equation, and the advection dispersion transport equation coupled with the dissolution equation. The flow equation is solved using the nonconforming Crouzeix-Raviart (CR) finite element approximation for the Stokes equation. For the transport equation, a combination between discontinuous Galerkin method and multipoint flux approximation method is proposed. The numerical effect of the dissolution is considered by using a dynamic mesh variation that increases the size of the mesh based on the amount of dissolved salt. The numerical method is applied to a 2D geological cross section representing a Horst and Graben structure in the Tabular Jura of northwestern Switzerland. The model simulates salt dissolution within the geological section and predicts the amount of vertical dissolution as an indicator of potential subsidence that could occur. Simulation results showed that the highest dissolution amount is observed near the normal fault zones, and, therefore, the highest subsidence rates are expected above normal fault zones

Cause inhabituelle d’une infection respiratoire récidivante: hypoplasie du poumon gauche

L'hypoplasie pulmonaire unilatérale est une malformation congénitale rare qui peut être découverte à l'âge adulte de façon fortuite ou par une infection respiratoire récidivante. Son diagnostic est établi par la tomodensitométrie thoracique avec injection du produit de contraste, et son traitement est essentiellement conservateur. Nous rapportons un cas d'hypoplasie pulmonaire gauche révélée chez un jeune de 20 ans par une infection respiratoire récidivanteKey words: Agénésie pulmonaire, hypoplasie pulmonaire, infection respiratoir

Screening of Mineral Elements in Cistus ladanifer and Cistus libanotis Essential Oils and their Leaves

peer reviewedThe aim of this study was to determine the levels of mineral compounds in Cistus ladanifer and Cistus libanotis growing in Eastern Morocco from two different regions Jerada (arid climate) and Tafoughalt (humid climate). A total of fifteen elements (Cd, Co, Cr, Cu, Hg, Na, Ni, P, Pb, Zn, Al, Ca, Fe, K and Mg) has been measured by inductive coupled plasma atomic emission spectrometry. Their concentrations have been found to vary in leaves and their essential oils. From the results of the study, P, Al, Ca, Fe, K and Mg are highest in all the samples analysed. Cr and Pb were not detected in essential oil of Cistus libanotis from Jerada and Tafoughalt, respectively. These plants were found to contain appreciable amounts of the elements K, Ca, Fe, Mg, P, Al, Ni, Li, Zn and Cu Witch are important in many biological mechanisms. This study also provides a comprehensive survey of the concentration of elements in plants due to their wide utilisation as herbal fusion or decoction in Eastern Morocco

Chemical composition and antioxidant activity of essential oil, various organic extracts of Cistus ladanifer and Cistus libanotis growing in Eastern Morocco

In the present work, we studied the chemical composition of the essential oil of Cistus ladanifer and Cistus libanotis growing in Eastern Morocco. The essential oils were obtained by hydrodistillation and their chemical composition was analysed using gas chromatography- mass spectrometry (GC–MS). Camphene, borneol, cyclohexanol-2, 2, 6 tremethyl, terpineol-4 and α-pinene were the main constituents of the essential oil of C. ladanifer, while in the essential oil of C. libanotis we obtained terpineol-4, γ-terpinene, camphene, sabinene, α-terpinene and α-pinene. The antioxidant potential of various extracts (water, ethanol, ethanol: water (50:50), methanol, methanol: water (50:50), acetonitrile) and essential oils of C. ladanifer and C. libanotis were carried out by the method of 1,1-diphenyl-1-picrylhydrazylhydrate (DPPH) free radical scavenging. Total phenolic and flavonoid contents were determined. The result show that C. ladanifer of the leaves of methanol: water (50:50) extract had the highest value of total phenolic content and the lowest was present in ethanol: water (50:50) extract of the stem and acetonitrile extract of the flowers of C. libanotis. From our experimental results, the extract of flowers, fruit, stem and leaves of those plants showed highest potential as free radical scavengers.Keywords: Antioxidant, phenolics, flavonoids, essential oil, extracts, gas chromatography- mass spectrometry (GC–MS).African Journal of Biotechnology Vol. 12(34), pp. 5314-532

Organisation et fonctionnement d’un écosystème côtier du Maroc : la lagune de Khnifiss

La lagune de Khnifiss, située au sud du Maroc, est une réserve biologique d’intérêt mondial pour l’avifaune. Des études pluridisciplinaires portant sur la physico-chimie des eaux, la biologie, la sédimentologie et les courants ont été réalisées par l’INRH dans la lagune en septembre 1998 et février 2001. Les résultats du courant obtenus montrent que la circulation des eaux à l’intérieur de la lagune est gérée par un courant alternatif et bidirectionnel : les courants du jusant sont plus importants que ceux du flot et varient également en fonction du rythme de la marée vive-eau/morte-eau. Ce mode de circulation des eaux attribue à la lagune une richesse en éléments azotés et phosphatés, surtout en période de vive-eau. La biomasse chlorophyllienne, assez importante dans la lagune, est causée par la richesse du milieu en éléments nutritifs et le phénomène d’upwelling qui se manifeste en été et au printemps dans la zone sud du Maroc. Ces études ont montré que la lagune de Khnifiss est un milieu propice à la conchyliculture. Néanmoins, l’installation de tout projet aquacole dans le site devra tenir compte de sa capacité trophique et de son équilibre écologique.The Moroccan coastal marine area has several zones that are targets for exploitation but must simultaneously be protected. Lagoons are considered to be among the most productive natural systems in the world, but they are also vulnerable systems due to natural and human constraints. Lagoons can also be a target of economic expansion. This is why an understanding about the state of these ecosystems is important in order to proceed with rational use of the resource. The Khnifiss lagoon, situated on the South Atlantic coast of Morocco, is a potential site for aquaculture and tourism if planned with an ecological awareness. The large surface area and high biological production for the avifauna qualify it to be among the four protected sites by the RAMSAR convention for humid zone conservation (lagoons of Khnifiss and Moulay Bousselham, lakes of Sidi Boughaba and Afennourir). The objective of this work was to complete previous studies and to estimate the nutritive richness of the Khnifiss lagoon. To understand the spatio-temporal variability in the water currents, and the physico-chemical and biological and characteristics of this lagoon, two surveys were organized in September 1998 and February 2001.The Khnifiss lagoon (20 km long and 65 km2 surface area) is situated between Tantan and Tarfaya (28°02'54'' N, 12°13'66'' W). It opens up into the Atlantic ocean by a narrow inlet called ''Foum Agouitir'', about 100 m wide. The lagoon continues upstream beyond a salt marsh, called "Sebkha Tazra". Physical, chemical and biological variables were monitored: temperature and salinity; dissolved oxygen, nitrates and phosphates; chlorophyll a. The current (direction and intensity) and the sediment were also studied. Samples were collected four times from the surface and bottom waters during spring tide (ST), neap tide (NT), low tide (LT) and high tide (HT) during two seasons (September 1998 and February 2001). Seven hydrological stations were sampled, representing the lagoon system and one reference station in a neighbouring zone (Hréf), which represents the marine zone of the lagoon. Temperature and salinity were measured with a multi-sensor probe. The chemical analyses were carried out according to methods suggested by AMINOT & CHAUSSEPIED (1983). Thirty (30) sediment samples were also collected. Currents were measured at two fixed points by two current-meters.Based on the hydrological characteristics of the lagoon, especially temperature, salinity, water circulation and the nature of sediment, three zones were identified :1. Zone I (downstream from the lagoon) was dominated by the ocean’s influence and included the Hréf, H1 and H2 stations. Maximum depths varied from 2.5 to 6.6 m, depending on the tide and location. The concentrations of the different hydrological parameters were controlled by the plug effect of the oceanic environment. The most important current in the lagoon was recorded in this zone in the spring tide (ST: 110 cm.s-1). The sediment was coarse and important water - sediment exchange was caused by the strong current recorded in this zone.2. Zone II (middle of the lagoon) was a transition zone with an intermediate oceanic influence. It was situated between the H3 and H5 stations. The size of the inlet and the important exchanges governed by currents caused by strong tides resulted in concentrations of the various parameters being similar to those in Zone I. Depths varied from 2.64 to 8.7 m. Waters were more saline during the LT and NT periods (36-41 practical salinity unit, or psu). The current decreased relative to that is zone I (56 cm.s-1 in September 1998 and 78 cm.s-1 in February 2001). In this zone the current moved preferentially towards the right strand at high tide and toward the left strand at low tide.3. Zone III (upstream in the lagoon) covered a different biotope compared to the first two zones. The waters were less deep (2.64 to 5.3 m) and included the stations H6, H7 and the upper part of the lagoon. This zone was characterized by a very low oceanic influence. Water temperature and salinity were higher, 24-26°C and 41-44 psu respectively, during the LT and NT periods.On the basis of the hydrological zonation, the conjunction of the climate descriptors (moderate wind, rare precipitation, absence of storms, moderate air temperature) of the lagoon and the strong hydrodynamic influence in the lagoon suggest that the Knifiss lagoon is a relatively unconfined ecosystem. The hydrodynamics of this lagoon permit a fast water renewal rate and insure a good environmental quality. In addition, studies carried out on the healthiness of this lagoon demonstrated not only a healthy environment, but also healthy shellfish. This diagnosis seemed to be related to the geographical location and important rates of water exchange. However, the absence of continental freshwater sources leads to an important increase in salinity and temperature at the level of the upstream zone (zone III). Zone III therefore cannot be considered for shellfish breeding.On the basis of the biological zones: With respect to the bathymetry of the lagoon (depths varied from 2.5 to 8.7 m), shellfish, in contrast to fish, require less water depth. Therefore, it is sufficient to search for a less turbulent zone, which offers sufficient planktonic food for the shellfish growth. In the Khnifiss lagoon, the taxonomy of the phytoplankton has not been yet studied. However, BENNOUNA (1999) demonstrated that the phytoplankton community was dominated by dinoflagellates and diatoms in the Oualidia and Sidi Moussa lagoons. RHARBI (2000) found that picophytoplankton were the principal breeding food source of oysters and clams in Oualidia lagoon. The source of shellfish for breeding is located in the neighbouring upwelling marine waters. Development projects planned for the lagoon must include an awareness programme for fishermen about the role that moderate and responsible shellfish breeding programs can play in the preservation and reconstitution of the marine resource as well as in the improvement of their incomes

The Black Swan – Knowing the Unknown in Projects

A “Black Swan” is produced when the gap between what we know and what we think we know becomes dangerously wide (Taleb, 2007). This concept is closely related to uncertainty and learning. A Black Swan event is usually a surprise, at least to the observer. However the Black Swan event very much depends on the observer. What may be a Black Swan surprise for a turkey is not a Black Swan surprise to its butcher; so the main objective is to “avoid being the turkey” by exploring and identifying areas of vulnerability in order to avoid surprises. In projects, while some may disagree, almost all failures, even catastrophic ones, are not really Black Swan events but a series of failures that alone may have a negative impact on project outcomes but combined lead to catastrophic failure. However it is surprising how often experienced project teams ignore the early warning signs and move forward into the project lifecycle despite serious problems in many areas that are keys to project success. This will ultimately lead to the Black Swan event materializing. That is when it is too late to take any preventive actions. This paper will characterize the Black Swan concept in projects and describe its nature and identify organizational mechanisms that can be useful in dealing with Black Swan surprises in projects. This study is mainly based on literature study, however carries out an assessment on examples of Black Swan events in order to better clarify the concept under study

Infrastructure Wi-Fi for connected autonomous vehicle positioning : a review of the state-of-the-art

In order to realize intelligent vehicular transport networks and self driving cars, connected autonomous vehicles (CAVs) are required to be able to estimate their position to the nearest centimeter. Traditional positioning in CAVs is realized by using a global navigation satellite system (GNSS) such as global positioning system (GPS) or by fusing weighted location parameters from a GNSS with an inertial navigation systems (INSs). In urban environments where Wi-Fi coverage is ubiquitous and GNSS signals experience signal blockage, multipath or non line-of-sight (NLOS) propagation, enterprise or carrier-grade Wi-Fi networks can be opportunistically used for localization or “fused” with GNSS to improve the localization accuracy and precision. While GNSS-free localization systems are in the literature, a survey of vehicle localization from the perspective of a Wi-Fi anchor/infrastructure is limited. Consequently, this review seeks to investigate recent technological advances relating to positioning techniques between an ego vehicle and a vehicular network infrastructure. Also discussed in this paper is an analysis of the location accuracy, complexity and applicability of surveyed literature with respect to intelligent transportation system requirements for CAVs. It is envisaged that hybrid vehicular localization systems will enable pervasive localization services for CAVs as they travel through urban canyons, dense foliage or multi-story car parks

Contribution à la dépollution d’un rejet textile par adsorption sur un coagulant à base du mélange fer/aluminium préparé par électrocoagulation

L’industrie textile consomme une grande quantité d’eau, générant ainsi des rejets liquides à charge élevée en divers types de polluants. Ces derniers produisent des effets nocifs sur l’environnement. Ce travail s’intéresse à la dépollution d’un rejet d’une industrie textile, par addition d’un coagulant synthétique à base de fer et d’aluminium, préparé par le procédé d’électrocoagulation. Les résultats ont montré que le traitement de ce rejet par ce coagulant, a permis d’atteindre un rendement d’élimination des matières colorantes de 83.37% en terme de demande chimique en oxygène (DCO).Mots clés: traitement, hydroxyde, coagulation, demande chimique en oxygèn

In-Line Microwave Nondestructive Evaluation of Packaged Food Products via the Support Vector Machine Algorithm

This paper presents a novel approach based on electromagnetic waves (EM) to classify food packages that hold water as one of the main ingredients from the inside into contaminated or uncontaminated products. A non-destructive technique that can handle a real-time food production line is proposed to achieve this goal. This technique combines the operation of a microwave sensing system (MW) with a machine learning (ML) classifier. An accuracy of 100% has been obtained from training the aforementioned ML tool on a dataset constructed from the retrieved scattering parameters of about 500 measuring samples

Conidiobolomycose rhinofaciale avec localisations cervicales, thoraciques et brachiales : à propos d’un cas nigérian

We report here the clinical case of a Nigerian adult patient who received medical care during October 2010, at the Center for Diagnosis and Treatment of Buruli ulcer in Pobè (Benin). He presented a massive facial tumor associated with several subcutaneous (cervical, thoracic and upper limbs) nodules, evolving since several years. Tissue samples collected at Pobè medical center were addressed to the mycology and histology laboratories of Angers University Hospital (France), according to the medical exchange agreement between the two institutions about the diagnosis and treatment of Buruli ulcer disease. Histological examination showed a Splendore-Hoeppli phenomenon, consisting of a granulomatous reaction made of eosinophilic polynuclear cells surrounding rare, large and irregular, non-septate hyphae. A filamentous fungus was isolated by cultivation of the clinical samples, which was identified as Conidiobolus coronatus. The patient was treated orally with daily doses of ketoconazole (400 mg per day). After 4 months of treatment, a marked regression of the facial lesion was obtained. A first constructive facial surgery was achieved, but the patient did not attend the second step. This case report allows us to remind the mycological diagnosis of this exotic mycosis, but also to emphasize the main difficulties encountered in medical management in the developing countries