A comprehensive literature classification of simulation optimisation methods

Simulation Optimization (SO) provides a structured approach to the system design and configuration when analytical expressions for input/output relationships are unavailable. Several excellent surveys have been written on this topic. Each survey concentrates on only few classification criteria. This paper presents a literature survey with all classification criteria on techniques for SO according to the problem of characteristics such as shape of the response surface (global as compared to local optimization), objective functions (single or multiple objectives) and parameter spaces (discrete or continuous parameters). The survey focuses specifically on the SO problem that involves single per-formance measureSimulation Optimization, classification methods, literature survey

Effect of PCP Pesticide Contamination on Soil Quality

In recent years, soil contamination with pesticides has become a crucial news issue with serious short- and long-term effects on human health and its environment. Pesticides play a significant role in the success of modern farming and food production. These compounds have potential for toxicity and adverse effects on human health and ecological soil systems. Pentachlorophenol (PCP) is one of the most recalcitrant chemicals polluting the environment for its stable aromatic ring system and chloride content. Nowadays, many sites are contaminated with this substance. In these areas, concentrations may stay high for a long time because of slow degradation in the soil due to the negative effects that PCP has on soil microbial populations. Bioremediation of PCP contaminated sites can be realized introducing directly, into a contaminated system, microorganisms able to consume selectively the target compound (bioaugmentation) or increasing the microbial indigenous population by addiction of nutrients in form of organic and/or inorganic fertilizers and biosolids (biostimulation). In the present chapter, we present an overview of the effect of PCP pesticide contamination on soil microbial populations (density and diversity), enzymatic activity and physicochemical parameters. Additionally, the bioremediation process will be detailed

Microbial richness in sandy-silty soil Tunisia and its role in arid zone fertilization

Arid zone are stressful environments, typified by alkaline soils low in organic matter, with biologically limiting extremes in water availability, temperature, and UV radiation. This study aims to analyze the microbial diversity of forest soil and its evolution considering climate change in a typical Mediterranean forest of cork oak (Quercus suber L.) and its importance in arid soil fertilization. The investigation was conducted in forest at north-western Tunisia. The study of the quality of the forest soil was based on physicochemical (pH, C, N, EC...) and microbiological (fungi and bacteria) analyses. A collection of strains has been isolated and identified morphologically (form, gram ...) and biochemically (enzymatic activity: catalase, oxidase ...). According to the results obtained, the forest soil has a pH of about 5.03 ± 0.2, C/N ratio 39.82±1.02. The count and fungi, non-filamentous and non-filamentous bacteria on solid soil show a great diversity that confers the fertility of the soil. An important number of strains of actinomycetes (45 isolates) and non-filamentous bacteria (82 isolates) showing distinctive morphological characteristics. The isolates enzymatic activity showed an important value. These obtained results give an idea on the microbe diversity that can be used in the field of bio-fertilization of poor microbial structure soils as the arid zones and oasis system

A comprehensive literature classification of simulation optimisation methods

Simulation Optimization (SO) provides a structured approach to the system design and configuration when analytical expressions for input/output relationships are unavailable. Several excellent surveys have been written on this topic. Each survey concentrates on only few classification criteria. This paper presents a literature survey with all classification criteria on techniques for SO according to the problem of characteristics such as shape of the response surface (global as compared to local optimization), objective functions (single or multiple objectives) and parameter spaces (discrete or continuous parameters). The survey focuses specifically on the SO problem that involves single per-formance measur

Potential of Aquatic Plants for Pesticide Removal in Wastewater: A Case Study on Pentachlorophenol

Today, soil and water pollution by pesticides is a serious problem worldwide. Compared with conventionally expensive, invasive, and sometimes ineffective techniques for pentachlorophenol (PCP) dealing, such as excavation, dredging and some chemical methods, in situ treatment strategies are more effective at reducing risk and decreasing expenditures on management. Among the in situ treatments, bioremediation (microbial remediation and phytoremediation) is thought to be capable in permanent pollutants elimination at low cost. Therefore, phytoremediation has received more attention in the last decade. Phytoremediation is applicable owing to its esthetic value, environment friendly, manipulation in situ and economic benefit. However, the previous phytoremediation studies mostly focused on the use of terrestrial plants and remediation of heavy metals. Sediments in aquatic environment are regarded as ultimate sink of organic contaminants, but little information is available on the possibility of use of aquatic macrophytes for remediation of organic toxicants in aquatic environment. It is, therefore, necessary to develop phytoremediation method of PCP by using aquatic macrophytes

A comprehensive literature classification of simulation optimisation methods

Simulation Optimization (SO) provides a structured approach to the system design and configuration when analytical expressions for input/output relationships are unavailable. Several excellent surveys have been written on this topic. Each survey concentrates on only few classification criteria. This paper presents a literature survey with all classification criteria on techniques for SO according to the problem of characteristics such as shape of the response surface (global as compared to local optimization), objective functions (single or multiple objectives) and parameter spaces (discrete or continuous parameters). The survey focuses specifically on the SO problem that involves single per-formance measur

Hybrid simulation-optimization methods: A taxonomy and discussion

The possibilities of combining simulation and optimization are vast and the appropriate design highly depends on the problem characteristics. Therefore, it is very important to have a good overview of the different approaches. The taxonomies and classifications proposed in the literature do not cover the complete range of methods and overlook some important criteria. We provide a taxonomy that aims at giving an overview of the full spectrum of current simulation-optimization approaches. Our study may guide researchers who want to use one of the existing methods, give insights into the cross-fertilization of the ideas applied in those methods and create a standard for a better communication in the scientific community. Future reviews can use the taxonomy here described to classify both general approaches and methods for specific application fields.The possibilities of combining simulation and optimization are vast and the appropriate design highly depends on the problem characteristics. Therefore, it is very important to have a good overview of the different approaches. The taxonomies and classifications proposed in the literature do not cover the complete range of methods and overlook some important criteria. We provide a taxonomy that aims at giving an overview of the full spectrum of current simulation-optimization approaches. Our study may guide researchers who want to use one of the existing methods, give insights into the cross-fertilization of the ideas applied in those methods and create a standard for a better communication in the scientific community. Future reviews can use the taxonomy here described to classify both general approaches and methods for specific application fields. (C) 2014 Elsevier B.V. All rights reserved

Contribution à l'étude expérimentale et numérique du comportement d'un limon sollicité en traction : Approche par éléments discrets

The study of the tensile strength behaviour of a clay soil constitutes a new field investigation. It is generally accepted in geotechnical engineering that soil exhibit no or negligible tensile strength. However, there is significant evidence that interparticle forces arising capillary is an origin of a significant tensile strength particularly for a fine and clayey soils. The experimental difficulties related to the tensile parameters determination remain. At the same time, the classical extrapolation of the indirect tensile tests, such Brazilian test and bending test, used usually in rock mechanics and for concrete, remain largely uncertain. One of these aspects is the difficulty to interpret the results from the different tests.The main purpose of this research was to experimentally examine the results via several Brazilian tests and bending tests and to use as numerical support the Distinct Element Method (DEM). This approach was accomplished by conducting several tests on the silt clay which was provided from Nabeul City. In fact the site was previously intended for a protection liner of a landfill. The major conclusions obtained from this research include experimental and numerical results, tended to improve that the split tensile test can not give the uniaxial tensile strength, even if we guarantee the in-center crack initiation by double flats diametrically opposite. However, the bending test can give a good prediction of the uniaxial tensile strength, especially using the analytical differential model. In fact, it seems that this model which is not based on a preferred behavior law assumption, leads to the same numerical stress diagram in tension zone.L'étude du comportement des sols fins sollicités en traction a suscité l'intérêt des chercheurs et des ingénieurs pour de nombreuses applications depuis plus d'un demi siècle. Cependant, elle est restée sans issues claires, notamment pour l'identification du comportement des sols en traction pour des états de saturations différentes. La complexité est essentiellement d'origine expérimentale. Cette question est de nouveau posée. Des contributions récentes, assez prometteuses, permettent d'apporter un éclairage nouveau sur ces aspects. Ce travail de recherches s'intègre donc dans cette voie, où l'on cherche à apporter des éléments de réponse quant à la faisabilité et à l'interprétation d'un certain nombre d'essais de laboratoire de traction directe ou indirecte.En se focalisant sur la détermination de la résistance à la traction d'un sol fin à un état de saturation donné, on a réalisé des essais au laboratoire sur un limon (assimilé à un matériau fin), se trouvant sur un site choisi initialement pour héberger un centre de stockage des déchets solides ménagers. La problématique relative à ce type d'application, est liée au fait qu'un tel sol (le limon) est utilisé majoritairement pour la construction de la couche de couverture, et qu'il risque donc d'être fortement sollicité en traction par flexion quand les déchets subissent des tassements. Dans ce but, l'étude expérimentale a été orientée vers des essais de traction indirecte à savoir l'essai de fendage et l'essai de flexion.La complexité d'une telle étude réside, d'une part, dans l'interprétation qu'on peut en faire et, d'autre part, dans le couplage des effets de plusieurs paramètres (liés à la préparation de l'échantillon, les conditions initiales de saturation et de densité des échantillons, les dimensions des éprouvettes, les conditions aux limites associées à ces essais).En faisant une étude paramétrique et une analyse fine de la réponse de ce matériau, via une méthodologie numérique qui nous semble bien appropriée (méthode des éléments distincts, DEM), nous avons apporté des éléments de réponse aux interprétations des essais de traction indirecte. L'approche DEM est appliquée selon une démarche de calibrage des paramètres sur la base des essais de cisaillement au triaxial. On montre que l'essai de fendage ne pourrait pas fournir la résistance à la traction uniaxiale (valeur de référence obtenue numériquement par la DEM par un essai de traction directe) même si l'initiation de la fissure apparaissait au centre. Une telle condition n'est satisfaite que pour un aplatissement de l'éprouvette cylindrique d'un angle au centre de la section par rapport à la génératrice variant de 10° à 12°.D'un autre côté, l'essai de flexion interprété selon le modèle différentiel semble donner une bonne estimation de la résistance à la traction uniaxiale.Dans ce travail de recherches, bien que la démarche numérique par éléments distincts semble dépendre des essais de laboratoire nécessaires au calage, sa potentialité demeure très importante puisque, non seulement elle offre l'opportunité de simuler des essais complexes de laboratoire, mais aussi elle permet d'avoir des outils d'interprétation fiables

Microbial richness in sandy-silty soil Tunisia and its role in arid zone fertilization

Arid zone are stressful environments, typified by alkaline soils low in organic matter, with biologically limiting extremes in water availability, temperature, and UV radiation. This study aims to analyze the microbial diversity of forest soil and its evolution considering climate change in a typical Mediterranean forest of cork oak (Quercus suber L.) and its importance in arid soil fertilization. The investigation was conducted in forest at north-western Tunisia. The study of the quality of the forest soil was based on physicochemical (pH, C, N, EC...) and microbiological (fungi and bacteria) analyses. A collection of strains has been isolated and identified morphologically (form, gram ...) and biochemically (enzymatic activity: catalase, oxidase ...). According to the results obtained, the forest soil has a pH of about 5.03 ± 0.2, C/N ratio 39.82±1.02. The count and fungi, non-filamentous and non-filamentous bacteria on solid soil show a great diversity that confers the fertility of the soil. An important number of strains of actinomycetes (45 isolates) and non-filamentous bacteria (82 isolates) showing distinctive morphological characteristics. The isolates enzymatic activity showed an important value. These obtained results give an idea on the microbe diversity that can be used in the field of bio-fertilization of poor microbial structure soils as the arid zones and oasis system