scholarly journals Current Knowledge and Future Challenges on Bacterial Degradation of the Highly Complex Petroleum Products Asphaltenes and Resins

2021 ◽  
Vol 9 ◽  
Author(s):  
Alexis Nzila ◽  
Musa M. Musa
Keyword(s):  
Current Knowledge ◽  
Petroleum Products ◽  
Oil Reservoirs ◽  
Bacterial Degradation ◽  
Degradation Mechanisms ◽  
Oil Viscosity ◽  
Research Areas ◽  
Oil Exploitation ◽  
Future Challenges ◽  
Petroleum Pollutants

Petroleum products consist mainly of aliphatics, aromatics, asphaltenes and resins. After oil exploitation, the concentrations of asphaltenes and resins are high in oil reservoirs; however, they are also the petroleum pollutants most recalcitrant to degradation, leading to high oil viscosity. A sizable amount of work has been dedicated to understand the degradation mechanisms of aliphatics and aromatics; however, in comparison, little work has been carried out on asphaltene and resin degradation. This review discusses our current knowledge on the understanding of asphaltene and resin degradation. More specifically, it sheds light on work carried out to date on the degradation of these pollutants, and highlights the major gaps that limit our understanding of their degradation pathways. It also presents new potential research areas that can be explored to fill in these gaps.

Community dynamics in highland watersheds

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Community Dynamics ◽  
Community Organization ◽  
Current Knowledge ◽  
Central Process ◽  
Spatial Variables ◽  
Research Areas ◽  
Local Extinctions ◽  
Metacommunity Dynamics ◽  
Natural Communities

Chapter 6 presents the interaction between space and time in determining the organization of natural communities in high altitude heterogeneous waterscapes. After explaining why high altitude waters represent suitable models for examining metacommunity organization, the chapter focuses on dispersal—a central process to allow colonization and establishment of populations in remote localities and to counter local extinctions. Community organization patterns are then described for a variety of organisms living in high altitude waters, from microbes to invertebrates to fish and birds. These patterns reveal that both environmental and spatial variables are generally involved in species assembling. Examples of studies on directional spatial processes (e.g. through wind and water flow), waterscape genetics, and temporal variability (synchrony/asynchrony) are highlighted as promising research areas to increase the current knowledge on high altitude metacommunity dynamics.

scholarly journals Synthetic protocell biology: from reproduction to computation

2007 ◽  
Vol 362 (1486) ◽  
pp. 1727-1739 ◽  
Author(s):  
Ricard V Solé ◽  
Andreea Munteanu ◽  
Carlos Rodriguez-Caso ◽  
Javier Macía
Keyword(s):  
Current Knowledge ◽  
Building Blocks ◽  
Biochemical Networks ◽  
Cellular Structures ◽  
Biological Complexity ◽  
Artificial Cell ◽  
Future Challenges ◽  
Cooperative Dynamics ◽  
The Origin Of Life ◽  
Review Current

Cells are the building blocks of biological complexity. They are complex systems sustained by the coordinated cooperative dynamics of several biochemical networks. Their replication, adaptation and computational features emerge as a consequence of appropriate molecular feedbacks that somehow define what life is. As the last decades have brought the transition from the description-driven biology to the synthesis-driven biology, one great challenge shared by both the fields of bioengineering and the origin of life is to find the appropriate conditions under which living cellular structures can effectively emerge and persist. Here, we review current knowledge (both theoretical and experimental) on possible scenarios of artificial cell design and their future challenges.

scholarly journals Lung Interstitial Macrophages: Past, Present, and Future

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Joey Schyns ◽  
Fabrice Bureau ◽  
Thomas Marichal
Keyword(s):  
Dendritic Cells ◽  
Alveolar Macrophages ◽  
Historical Perspective ◽  
Current Knowledge ◽  
Allergic Airway Inflammation ◽  
Immune Functions ◽  
Immune Mediated ◽  
Future Challenges ◽  
Long Time ◽  
Review Current

For a long time, investigations about the lung myeloid compartment have been mainly limited to the macrophages located within the airways, that is, the well-known alveolar macrophages specialized in recycling of surfactant molecules and removal of debris. However, a growing number of reports have highlighted the complexity of the lung myeloid compartment, which also encompass different subsets of dendritic cells, tissue monocytes, and nonalveolar macrophages, called interstitial macrophages (IM). Recent evidence supports that, in mice, IM perform important immune functions, including the maintenance of lung homeostasis and prevention of immune-mediated allergic airway inflammation. In this article, we describe lung IM from a historical perspective and we review current knowledge on their characteristics, ontogeny, and functions, mostly in rodents. Finally, we emphasize some important future challenges for the field.

scholarly journals Mechanisms on the Injection Conformance Reversion during Polymer Flooding of Offshore Heterogeneous Heavy-Oil Reservoirs

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhijie Wei ◽  
Xiaodong Kang ◽  
Yuyang Liu ◽  
Hanxu Yang
Keyword(s):  
Polymer Solution ◽  
Heavy Oil ◽  
Flow Resistance ◽  
Polymer Flooding ◽  
Production Performance ◽  
Oil Reservoirs ◽  
Resistance Force ◽  
Oil Viscosity ◽  
Permeable Layer ◽  
Heavy Oil Reservoirs

Injection conformance reversion commonly observed during polymer flooding in offshore heterogeneous heavy-oil reservoirs weakens the volumetric sweep of polymer solution and compromises its EOR results. To investigate its mechanisms and impact factors, one mathematical model to predicate injection conformance behavior is constructed for heterogeneous reservoirs based on the Buckley-Leverett function. The different suction capability of each layer to polymer solution results in distinct change law of the flow resistance force, which in turn reacts upon the suction capability and creates dynamic redistribution of injection between layers. Conformance reversion takes place when the variation ratio of flow resistance force of different layers tends to be the same. The peak value and scope of conformance reversion decrease and reversion timing is advanced as oil viscosity or permeability contrast increases, or polymer concentration or relative thickness of low permeable layer decreases, which compromises the ability of polymer flooding to improve the volumetric sweep and lower suction of the low permeable layer. The features of offshore polymer flooding tend to make the injection conformance V-type and create low-efficiency circulation of polymer in a high permeable layer more easily. These results can provide guidance to improve the production performance of polymer flooding in offshore heterogeneous heavy-oil reservoirs.

scholarly journals Current Status of- and Future Perspectives in- Bacterial Degradation of Benzo[a]pyrene

2020 ◽  
Author(s):  
Alexis Nzila ◽  
Musa M. Musa
Keyword(s):  
Molecular Weight ◽  
Current Knowledge ◽  
Bacterial Degradation ◽  
Current Status ◽  
Low Molecular Weight ◽  
Future Perspectives ◽  
Aromatic Rings ◽  
Compound A ◽  
Current Review ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAHs), which consist of low-molecular-weight PAHs (LMW-PAHs) and high-molecular-weight PAHs (HMW-PAHs), form an important class of pollutants. Pyrene and benzo[a]pyrene (BaP) are the main pollutants belonging to HMW-PAHs, and their degradation by microorganisms remains an important strategy for their removal from the environments. Extensive studies have been carried out on the isolation and characterisation of microorganisms that actively degrade LMW-PAHs, and to a certain extent, the HMW-PAH pyrene. However, so far, limited work has been carried out on BaP biodegradation. BaP consists of five fused aromatic rings, which confers this compound a high stability, rendering it less amenable to biodegradation. The current review summarizes the emerging reports on BaP biodegradation. More specifically, work carried out on BaP bacterial degradation and current knowledge gaps that limit our understanding of BaP degradation are highlighted. Moreover, new avenues of research on BaP degradation are proposed, specifically in the context of the development of “omics” approaches

scholarly journals Human Gaze Assisted Artificial Intelligence: A Review

2020 ◽  
Author(s):  
Ruohan Zhang ◽  
Akanksha Saran ◽  
Bo Liu ◽  
Yifeng Zhu ◽  
Sihang Guo ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Language Processing ◽  
Cognitive State ◽  
Data Sets ◽  
Common Goal ◽  
Research Areas ◽  
Future Challenges ◽  
Potential Applications ◽  
High Level ◽  
And Robotics

Human gaze reveals a wealth of information about internal cognitive state. Thus, gaze-related research has significantly increased in computer vision, natural language processing, decision learning, and robotics in recent years. We provide a high-level overview of the research efforts in these fields, including collecting human gaze data sets, modeling gaze behaviors, and utilizing gaze information in various applications, with the goal of enhancing communication between these research areas. We discuss future challenges and potential applications that work towards a common goal of human-centered artificial intelligence.

Experimental Analysis of the Effects of Varying Temperature and Viscosities on Foamy Oil Production

2021 ◽  
Author(s):  
Jasmine Shivani Medina ◽  
Iomi Dhanielle Medina ◽  
Gao Zhang
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Elevated Temperatures ◽  
Oil Production ◽  
Oil Reservoirs ◽  
Oil Viscosity ◽  
Gas Recovery ◽  
Foamy Oil ◽  
Heavy Oil Reservoirs ◽  
Pressure Depletion

Abstract The phenomenon of higher than expected production rates and recovery factors in heavy oil reservoirs captured the term "foamy oil," by researchers. This is mainly due to the bubble filled chocolate mousse appearance found at wellheads where this phenomenon occurs. Foamy oil flow is barely understood up to this day. Understanding why this unusual occurrence exists can aid in the transfer of principles to low recovery heavy oil reservoirs globally. This study focused mainly on how varying the viscosity and temperature via pressure depletion lab tests affected the performance of foamy oil production. Six different lab-scaled experiments were conducted, four with varying temperatures and two with varying viscosities. All experiments were conducted using lab-scaled sand pack pressure depletion tests with the same initial gas oil ratio (GOR). The first series of experiments with varying temperatures showed that the oil recovery was inversely proportional to elevated temperatures, however there was a directly proportional relationship between gas recovery and elevation in temperature. A unique observation was also made, during late-stage production, foamy oil recovery reappeared with temperatures in the 45-55°C range. With respect to the viscosities, a non-linear relationship existed, however there was an optimal region in which the live-oil viscosity and foamy oil production seem to be harmonious.

Wireless Sensor Network as Enabling Technology for Cyber-Physical System

2018 ◽  
pp. 26-53
Author(s):  
Jiwa Abdullah ◽  
Nayef Abdulwahab Alduais
Keyword(s):  
Physical System ◽  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Network Connectivity ◽  
Physical World ◽  
Wireless Sensor ◽  
Cyber Physical System ◽  
Research Areas ◽  
Future Challenges ◽  
Object Interactions

Within the last 20 years, wireless communication and network has been one of the fastest-growing research areas. Significant progress has been made in the fields of mobile ad hoc network (MANET) and wireless sensor networks (WSN). Very recently, the cyber-physical system (CPS) has emerged as a promising direction to enrich human-to-human, human to-object, and object-to-object interactions in the physical world as well as in the virtual world. The possibilities are enormous, such that CPS would adopt, and even nurture, the areas of MANET and WSN because more sensor inputs and richer network connectivity are required. The chapter reviews what has been developed in these fields, outlines the projection of what may happen in the field of CPS, and identifies further works. The authors identify the unique features of WSN, raising some CPS critical examples, and then directing the future challenges of CPS. In order to fully comprehend the connection of WSN to CPS, the authors provide some preliminaries of WSN and establish their necessary connections.

scholarly journals Biliary tract cancers: current knowledge, clinical candidates and future challenges

2019 ◽  
Vol Volume 11 ◽  
pp. 2623-2642 ◽  
Author(s):  
Noor-ul-Ain Tariq ◽  
Mairéad G McNamara ◽  
Juan W Valle
Keyword(s):  
Biliary Tract ◽  
Current Knowledge ◽  
Biliary Tract Cancers ◽  
Future Challenges
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