Application of Rhamnolipid and Microbial Activities for Improving the Sedimentation of Oil Sand Tailings

Densification of oil sand tailings deposited in the tailing ponds and recovering water from them are two major challenges issues in the oil sands surface mining industry. A small increase in the tailing settlement rate (which normally is very slow) can improve the densification of tailings and significantly, reduce water consumption and the volume of tailing ponds. Currently most of the industrial methods for consolidation of oil sand tailings are based on clay particle flocculation methods which use different kinds of agents such as calcium sulfate (gypsum), and polymeric flocculants. In this work, rhamnolipid (JBR 425) was investigated as a flocculating agent and microbial activities by performing the sedimentation experiments to increase the sedimentation of fine tailing particles. It has been found that rhamnolipid increased sedimentation by improving the hydrophobic interaction between the particles. The feasibility of in situ biosurfactant production by indigenous microorganisms, Bacillus subtilis strain and two microbial strains isolated from weathered oil was investigated and it was found that all strains could produce very low amounts of biosurfactant. A mixed culture of two microbial strains isolated from weathered oil increased the sedimentation. Different concentrations of rhamnolipid together with these two microbial strains at 23 ºC ºC could lead to significant increases in sedimentation (by a maximum factor of 3.04), increases in the concentration of larger particles (by a maximum factor of 1.9), particle mean diameter (by a maximum factor of 2.11) and flocculation in the tailings samples amended with them compared to the control. Rhamnolipid (0.5%) together with these two microbial strains at 15 ºC ºC showed significant increases in sedimentation (by a factor of 5.1), the concentration of larger particles (by a factor of 2.63), particle mean diameter (by a factor of 2.70) and flocculation in the tailings samples compared to the control. while the zeta potential is still negative. According to the pH measurements (during the 50 days) increase in the ionic strength (I) of the pore water and reduction in the thickness of the DDL of clay particles is not responsible for increasing the sedimentation as dissolution of MFT carbonate minerals and releasing divalent cations could not occur at pH higher than 7.5. However there might be a small amount of CH4 production at 15 ºC oC in the deeper layer of mud. This means that the mechanism of flocculation in these cases could be probably due to increasing the hydrophobicity of the particles, due to the interaction of biosurfactant and high molecular weight microbial organic compounds through a bridging mechanism with clay particles, and to due to forming transient canals from small amounts of CH4 production. Using rhamnolipid as a flocculating agent could bring the remaining oil and also a small amount of insoluble heavy metals from the tailing sediment into the water. Dissolved heavy metal ions and rhamnolipid in water could be removed through micellar- enhanced ultrafiltration (MEUF) process (between 30% for Cd and 100% for V, and 97.5% for rhamnolipid). This work shows the potential of using rhamnolipid and microbial culture in order to increase the oil sand sedimentation through flocculation and microbial activity in a more environmental friendly and densification process

Application of Rhamnolipid and Microbial Activities for Improving the Sedimentation of Oil Sand Tailings

Densification of oil sand tailings deposited in the tailing ponds and recovering water from them are two major challenges issues in the oil sands surface mining industry. A small increase in the tailing settlement rate (which normally is very slow) can improve the densification of tailings and significantly, reduce water consumption and the volume of tailing ponds. Currently most of the industrial methods for consolidation of oil sand tailings are based on clay particle flocculation methods which use different kinds of agents such as calcium sulfate (gypsum), and polymeric flocculants. In this work, rhamnolipid (JBR 425) was investigated as a flocculating agent and microbial activities by performing the sedimentation experiments to increase the sedimentation of fine tailing particles. It has been found that rhamnolipid increased sedimentation by improving the hydrophobic interaction between the particles. The feasibility of in situ biosurfactant production by indigenous microorganisms, Bacillus subtilis strain and two microbial strains isolated from weathered oil was investigated and it was found that all strains could produce very low amounts of biosurfactant. A mixed culture of two microbial strains isolated from weathered oil increased the sedimentation. Different concentrations of rhamnolipid together with these two microbial strains at 23 ºC ºC could lead to significant increases in sedimentation (by a maximum factor of 3.04), increases in the concentration of larger particles (by a maximum factor of 1.9), particle mean diameter (by a maximum factor of 2.11) and flocculation in the tailings samples amended with them compared to the control. Rhamnolipid (0.5%) together with these two microbial strains at 15 ºC ºC showed significant increases in sedimentation (by a factor of 5.1), the concentration of larger particles (by a factor of 2.63), particle mean diameter (by a factor of 2.70) and flocculation in the tailings samples compared to the control. while the zeta potential is still negative. According to the pH measurements (during the 50 days) increase in the ionic strength (I) of the pore water and reduction in the thickness of the DDL of clay particles is not responsible for increasing the sedimentation as dissolution of MFT carbonate minerals and releasing divalent cations could not occur at pH higher than 7.5. However there might be a small amount of CH4 production at 15 ºC oC in the deeper layer of mud. This means that the mechanism of flocculation in these cases could be probably due to increasing the hydrophobicity of the particles, due to the interaction of biosurfactant and high molecular weight microbial organic compounds through a bridging mechanism with clay particles, and to due to forming transient canals from small amounts of CH4 production. Using rhamnolipid as a flocculating agent could bring the remaining oil and also a small amount of insoluble heavy metals from the tailing sediment into the water. Dissolved heavy metal ions and rhamnolipid in water could be removed through micellar- enhanced ultrafiltration (MEUF) process (between 30% for Cd and 100% for V, and 97.5% for rhamnolipid). This work shows the potential of using rhamnolipid and microbial culture in order to increase the oil sand sedimentation through flocculation and microbial activity in a more environmental friendly and densification process

Application of Rhamnolipid and Microbial Activities for Improving the Sedimentation of Oil Sand Tailings

Densification of oil sand tailings deposited in the tailing ponds and recovering water from them are two major challenges issues in the oil sands surface mining industry. A small increase in the tailing settlement rate (which normally is very slow) can improve the densification of tailings and significantly, reduce water consumption and the volume of tailing ponds. Currently most of the industrial methods for consolidation of oil sand tailings are based on clay particle flocculation methods which use different kinds of agents such as calcium sulfate (gypsum), and polymeric flocculants. In this work, rhamnolipid (JBR 425) was investigated as a flocculating agent and microbial activities by performing the sedimentation experiments to increase the sedimentation of fine tailing particles. It has been found that rhamnolipid increased sedimentation by improving the hydrophobic interaction between the particles. The feasibility of in situ biosurfactant production by indigenous microorganisms, Bacillus subtilis strain and two microbial strains isolated from weathered oil was investigated and it was found that all strains could produce very low amounts of biosurfactant. A mixed culture of two microbial strains isolated from weathered oil increased the sedimentation. Different concentrations of rhamnolipid together with these two microbial strains at 23 ºC ºC could lead to significant increases in sedimentation (by a maximum factor of 3.04), increases in the concentration of larger particles (by a maximum factor of 1.9), particle mean diameter (by a maximum factor of 2.11) and flocculation in the tailings samples amended with them compared to the control. Rhamnolipid (0.5%) together with these two microbial strains at 15 ºC ºC showed significant increases in sedimentation (by a factor of 5.1), the concentration of larger particles (by a factor of 2.63), particle mean diameter (by a factor of 2.70) and flocculation in the tailings samples compared to the control. while the zeta potential is still negative. According to the pH measurements (during the 50 days) increase in the ionic strength (I) of the pore water and reduction in the thickness of the DDL of clay particles is not responsible for increasing the sedimentation as dissolution of MFT carbonate minerals and releasing divalent cations could not occur at pH higher than 7.5. However there might be a small amount of CH4 production at 15 ºC oC in the deeper layer of mud. This means that the mechanism of flocculation in these cases could be probably due to increasing the hydrophobicity of the particles, due to the interaction of biosurfactant and high molecular weight microbial organic compounds through a bridging mechanism with clay particles, and to due to forming transient canals from small amounts of CH4 production. Using rhamnolipid as a flocculating agent could bring the remaining oil and also a small amount of insoluble heavy metals from the tailing sediment into the water. Dissolved heavy metal ions and rhamnolipid in water could be removed through micellar- enhanced ultrafiltration (MEUF) process (between 30% for Cd and 100% for V, and 97.5% for rhamnolipid). This work shows the potential of using rhamnolipid and microbial culture in order to increase the oil sand sedimentation through flocculation and microbial activity in a more environmental friendly and densification process

Analysis of blood flow during vascular development in chick embryos

The cardiovascular system is the first fully functional organ system in the vertebrate embryo. Proper formation of the vasculature is essential for proper embryonic development. Blood flow plays a significant role in the adaptable characteristics of the vessels, as well as innetwork remodelling. As soon as blood flow begins, vessels respond to external stimuli such asshear stress, the tangential force created by the blood flow, which affect the surrounding tissue. Shear stress is the product of both the velocity profile in the vessel and the viscosity of the flowing fluid, and these parameters were determined in vivo. In this research, we have measured changes in the flow velocity, using micro particle image velocimetry (µPIV) at different somite stages during the development of the chick embryo. We measured the viscosity of avian embryonic blood for the first time ever, using a micro viscometer and calculated the change inshear stress during vascular remodelling. We observed that shear stress increases after the onset of blood flow (14 somites), until the stage where large vessels become obvious (25 somites) where a decrease in shear stress is observed. Furthermore, we found that the apparent hematocrit with respect to vessel diameter decreases with decreasing vessel radius, an effect known as the Fahreus-Lindqvist effect. We also found that the embryonic blood viscosity is non-Newtonian and displays shear-thinning behavior, similar to adult blood.Le système cardiovasculaire est le premier organe entièrement fonctionnel chez l'embryon vertébré. Une formation appropriée de la vascularisation est indispensable pour le bon développement embryonnaire. Le flux sanguin a un rôle important autant dans les caractéristiques d'adaptation vasculaire que dans le remodelage. Dès que le flux sanguin commence, les vaisseaux répondent aux stimuli externes tels que les forces de cisaillement (shear stress) et la force tangentielle créée par le flux sanguin, ce qui affecte le tissu environnant. Le shear stress est le résultat du produit de la vitesse dans le vaisseau avec la viscosité du flux, paramètres ayant été déterminés in vivo. Dans cette étude, nous avons mesuré les changements de la vitesse de flux en utilisant la technique de micro particle image velocimetry (µPIV) à différents stades (somites) du développement de l'embryon de poulet. Pour la première fois, nous avons mesuré la viscosité du sang embryonnaire aviaire en utilisant un micro viscomètre et nous avons calculé le changement de shear stress au cours du remodelage vasculaire. Nous rapportonsque les niveaux de shear stress augmentent après le début du flux sanguin (14 somites) jusqu'au stade où de gros vaisseaux deviennent apparents (25 somites), stade auquel nous observons une diminution des niveaux de shear stress. En outre, l'hématocrite relié au diamètre vasculaire, diminue lors d'une réduction du rayon vaculaire, effet connu sous le nom d'effet de Fahreus-Lindqvist. Nous constatons aussi que la viscosité du sang embryonnaire n'est pas newtonienne et démontre un comportement de réduction du shear stress, observation similaire au sang adulte

Visual event description in videos

This thesis focuses on monitoring non-specific and unconstrained activities and events in videos in order to build a complete scene understanding system. The particular emphasis in this work is based on the spatio-temporal context of the scene. This thesis proposes a unique solution using a hierarchical framework of video fragments to create a dynamically changing model of the scene. The model is then used to simultaneously detect and localize an event of interest, detect abnormal (rare) events, and track all moving objects in the scene. The approach can be considered as an extension to the original Bag-of-Video-Words approaches in which a spatio-temporal scene configuration comes into play. It does not require prior knowledge about actions and events, background subtraction, motion estimation or tracking. It is also robust to spatial and temporal scale changes, as well as some deformations. The hierarchical algorithm uses a probabilistic framework to code a video as a compact set of local spatio-temporal visual features, while considering their spatio-temporal compositions in order to account for the scene context. A significant aspect of the methodology is the way that we represent scene information while keeping the computational cost low enough for real-time implementation using the current hardware resources. Given the adaptive shape- and motion-based model, the events can be described and localized in the videos. These events are interpreted by a complete scene understanding system that uses different inference mechanisms and learning strategies to describe ongoing events in a video, identify abnormal patterns is space and time, find similar videos to a query based on their contents, and track all moving objects in the scene without using any object detection method. We have extensively tested all our system on popular benchmarks and shown that they are both effective and robust for all of the aforementioned tasks. Moreover, the results are highly competitive with state-of-the-art methods. However, a major advantage of our approach is that it does not require any feature analysis, background/foreground segmentation and tracking, and is susceptible to online real-time analysis.Cette thèse porte sur le suivi des activités et des événements non spécifiques et sans contraintes dans les vidéos afin de construire un système de compréhension complète de scène. Ce travail porte une importance particulière sur le contexte spatio-temporel de la scène. Cette thèse propose une solution unique qui utilise un cadre hiérarchique de fragments de vidéo pour créer un modèle de changement dynamique de la scène. Le modèle est ensuite utilisé pour détecter et localiser simultanément un événement d'intérêt, détecter les événements anormaux (rares) et suivre tous les objets en mouvement dans la scène.L'approche peut être considérée comme une extension de l'approche originale Bag-of-Video-Words dans laquelle une configuration de la scène spatio-temporelle entre en jeu. Elle ne nécessite pas de connaissance préalable sur les actions et les événements, la soustraction d'image de fond, l'estimation de mouvement ou de suivi. Elle est également robuste aux changements d'échelle spatiale et temporelle ainsi que certaines déformations. L'algorithme hiérarchique utilise un cadre probabiliste pour coder une vidéo comme un ensemble compact de caractéristiques visuelles spatio-temporelles locales, tout en tenant compte de leurs compositions spatio-temporelles afin de tenir compte du contexte de la scène.Un aspect important de la méthodologie est la façon dont l'information de la scène est représentée tout en gardant un niveau minimal de calcul mais suffisant pour la mise en œuvre en temps réel en utilisant les ressources matérielles actuelles.Compte tenu du modèle adaptatif basé sur la forme et le mouvement, les événements peuvent être décrits et localisés dans les vidéos. Ces événements sont interprétés par un système de compréhension complète de scène qui utilise différents mécanismes d'inférence et de stratégies d'apprentissage pour décrire les événements en cours dans une vidéo, identifie les tendances anormales dans l'espace et le temps, trouve des vidéos similaires à une requête basée sur leur contenu et fait le suivi de tous les objets en mouvement dans la scène sans utiliser de procédé de détection d'objet.Nous avons testé à plusieurs reprises notre système en entier sur des références populaires et montré qu'il est à la fois efficace et robuste pour toutes les tâches mentionnées ci-dessus. De plus, les résultats sont très compétitifs avec les méthodes à la fine pointe de la technologie. Cependant, un avantage majeur de notre approche est qu'elle ne nécessite pas d'analyse de fonction, de segmentation et de suivi d'image de fond ou de premier plan et offre l'opportunité à l'analyse en ligne

Emotional Control of Inverted Pendulum System, A soft switching from imitative to emotional learning

Model-free control of unidentified systems with unstable equilibriums results in serious problems. In order to surmount these difficulties, firstly an existing model-based controller is used as a mentor for emotional-learning controller. This learning phase prepares the controller to behave like the mentor, while prevents any instability. Next, the controller is softly switched from model based to emotional one, using a FIS. Also the emotional stress is softly switched from the mentor-imitator output difference to the combination of objectives generated by a FIS which attentionally modulated stresses. For evaluating the proposed model free controller, a laboratorial inverted pendulum is employed

Imitative Learning Based Emotional Controller for Unknown Systems with Unstable Equilibrium

Purpose – Intelligent control for unidentified systems with unstable equilibriums is not always a proper control strategy, which results in inferior performance in many cases. Because of the existing trial and error manner of the procedure in former duration of learning, this exploration for finding the appropriate control signals can lead to instability. However, the recent proposed emotional controllers are capable of learning swiftly; the use of these controllers is not an efficient solution for the mentioned instability problems. Therefore, a solution is needed to evade the instability in preliminary phase of learning. The purpose of this paper is to propose a novel approach for controlling unstable systems or systems with unstable equilibrium by model free controllers. Design/methodology/approach – An existing controller (model-based controller) with limited performance is used as a mentor for the emotional learning controller in the first step. This learning phase prepares the controller to control the plant as well as mentor, while it prevents any instability. When the emotional controller can imitate the behavior of model based one properly, the employed controller is gently switched from model based one to an emotional controller using a fuzzy inference system (FIS). Also, the emotional stress is softly switched from the mentor-imitator output difference to the combination of the objectives. In this paper, the emotional stresses are generated once by using a nonlinear combination of objectives and once by employing different stresses to a FIS which attentionally modulated the stresses, and makes a subset of these objectives salient regarding the contemporary situation. Findings – The proposed model free controller is employed to control an inverted pendulum system and an oscillator with unstable equilibrium. It is noticeable that the proposed controller is a model free one, and does not use any knowledge about the plant. The experimental results on two benchmarks show the superiority of proposed imitative and emotional controller with fuzzy stress generation mechanism in comparison with model based originally supplied controllers and emotional controller with nonlinear stress generation unit – in control of pendulum system – in all operating conditions. Practical implications – There are two test beds for evaluating the proposed model free controller performance which are discussed in this paper: a laboratorial inverted pendulum system, which is a well-known system with unstable equilibrium, and Chua's circuit, which is an oscillator with two stable and one unstable equilibrium point. The results show that the proposed controller with the mentioned strategy can control the systems with satisfactory performance. Originality/value – In this paper, a novel approach for controlling unstable systems or systems with unstable equilibrium by model free controllers is proposed. This approach is based on imitative learning in preliminary phase of learning and soft switching to an interactive emotional learning. Moreover, FISs are used to model the linguistic knowledge of the ascendancy and situated importance of the objectives. These FISs are used to attentionally modulate the stress signals for the emotional controller. The results of proposed strategy on two benchmarks reveal the efficacy of this strategy of model free control