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2019 — A Comprehensive Study and Mechanism Investigation for Alkaline-Heavy Oil Recovery ProcessRésumé
Alkaline flooding is an important branch of chemical enhanced oil recovery (EOR). The complexity of alkaline flooding study is mainly embodied by its chemical reaction required by alkalis to react with oil acids. Consequently, in-situ surfactants are generated for various emulsification phenomenon. It is known that alkaline flooding performance in oil recovery is subjected to the emulsion type generation, thus, of great importance to alkaline flooding study is its mechanism investigation and saponification rate examination. In this study, a modified bottle test method that assesses major emulsion type formation for preliminary prediction of alkaline flooding performance in oil recovery is … Lire la suite
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2016 — Nonlinear Behaviors Analysis and Nonlinear Characteristics Diagnosing of Mechanical Vibration SystemsRésumé
Comprehensive understanding and effective diagnosis of nonlinear behaviors are important in dynamical analyses of mechanical systems and may provide crucial guidance to the design and control of mechanical systems. In this research, the nonlinear behavior and stability of an elastic suspended cable under combined parametric and external excitations are studied first. Such cable is commonly used in suspended bridges. The governing equations of the cable with geometric nonlinearity are developed with considerations of the first in-plane and out-of-plane mode vibrations. The solutions of the nonlinear system are derived as per the perturbation method of higher accuracy. The nonlinear stability of … Lire la suite
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2022 — Experimental and numerical investigations on wind characteristics and wind induced vibrations of bridge structuresRésumé
As more and more flexible structures such as long span bridges and suspension bridges are built in the world, their increased flexibility can cause serious concerns for researchers and engineers. For such structures, wind load has become one of the most important dominant loads under consideration in the analysis and design of structures. Thus, accurate and reliable evaluations of the wind characteristics are critical, as the evaluations may provide a solid foundation for which the design of wind-resistant structures can be relied upon. Therefore, according to the importance and sensitivity of this subject in some special applications, the current research … Lire la suite
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2023 — Improvement of weakly compressible moving particle semi-implicit method and its applicationRésumé
Moving Particle semi-implicit method (MPS) is one of the well-known Lagrange particle methods that is advantageous in addressing complex hydraulic engineering problems. Although the accuracy and reliability can be addressed in particle methods, instability arises due to pressure fluctuations from particle clustering and improvements are beneficial for method development. Particle distribution is an area that requires improvement. In this study, a particle smoothing algorithm was developed and incorporated to the weakly compressible MPS, namely sWCMPS. From the definition and derivation of basic MPS operators, uniform particle distribution is critically important to numerical accuracy. Within the framework of sWCMPS, numerical operators … Lire la suite
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2017 — Semi-Analytical Modeling of Fluid Flow and Solid Deformation in Heterogeneous Reservoirs using Universal Boundary Integral ApproachesRésumé
In the Canadian oil and gas industry, heavy oil and unconventional reservoirs play a vital role in sustaining the production of crude oil and face tremendous technical challenges of enhancing recovery while reducing environmental footprints. Among various development technologies, the cold heavy oil production with sand (CHOPS) and hydraulic fracturing techniques have been widely applied in Western Canadian basins to unlock the unconsolidated heavy oil and tight formation reservoirs, respectively. Both technologies are proved to be efficient during the primary production period; however, they suffer sharp production decline and low recovery factor. Moreover, during the enhanced oil recovery (EOR) phase, … Lire la suite
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2012 — Study on Wormhole Coverage, Foamy Oil Phenomenon, and Well Interference of Cold Heavy Oil Production with Sand WellsRésumé
In Cold Heavy Oil Production with Sand (CHOPS) wells, the presence of wormholes is considered to be one of the most important factors that contribute to enhanced production rate. Quantitative detection of wormholes can offer important parameters in further optimization of post-CHOPS processes such as post-CHOPS EOR planning and infill well drilling. Moreover, foamy oil is one of the most complex phenomena in CHOPS wells because gas starts mixing with oil and forming relatively continuous foam with high compressibility once the pressure drops to a certain point during depletion. A CHOPS reservoir with two zones including a foamy oil zone … Lire la suite
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2022 — Modified half logistic - exponentiated Kumaraswamy distribution and applicationsRésumé
The statistical model of mixture distributions has become an important tool for analyzing complicated phenomena in the real world. This approach has a wide range of applications in the fields of biology, medicine, environment and engineering. Based on the characteristics of the Exponentiated Kumaraswamy model, researchers have carried out a series of explorations and studies. However, in order to provide a more appropriate model to support real-life applications and to make our data analysis more reliable, it is still meaningful to explore new models. Therefore, in this thesis, we propose a novel mixture model, which is a modified one based … Lire la suite
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2013 — A WC-MPS Model for Viscous Free Surface FlowsRésumé
Computer-based numerical simulation has become a significant and very popular approach for solving engineering problems in the past few decades. It provides a safe and efficient tool to engineering investigations. It can even provide the knowledge that cannot be obtained directly through other methods. In other words, numerical simulation provides the assistance to interpret the theoretical phenomena and offers an alternative way to insightfully study the theories or experiments. In hydrodynamics simulations, the tradition mesh-based methods have been the dominant methods for decades, but they will fail in the simulation of free surface flow problems due to the large deformation … Lire la suite
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2019 — Aquatic Toxicity of Pharmaceuticals and Personal Care Products to AlgaeRésumé
This dissertation research provides a comprehensive study on aquatic toxicity of Pharmaceuticals and personal care products (PPCPs) to algae. The research studied dose- and time-dependent effects, multiple endpoint responses, algae species sensitivity, interactive environmental factors, and interactive multiple contaminents, as well as advanced emerging techniques. The toxicity of triclosan and carbamazepine to Chlorococcum sp. was studied using synchrotron-based Fourier transform infrared (SR-FTIR) spectromicroscopy. Triclosan can affect algae by inhibiting fatty acid synthesis and causing protein aggregation. Carbamazepine can disorganize phospholipid bilayers and attack specific proteins to disturb the transportation of ions and CO2. Carbamazepine-exposed cells developed a resistance with time … Lire la suite
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2015 — Characteristics of Tight Reservoirs in the Oligocene Huagang Formation, Xihu Sag, East China Sea BasinRésumé
The Xihu Sag in the East China Sea Basin can be divided into five structural belts. From west to east, they are western slope belt, western sub-sag, central inversion tectonic belt, eastern sub-sag and eastern fault and fold belt. The petrographical, diagenetic and petrophysical properties of the Oligocene Huagang Formation were studied in terms of the structural belts. The Huagang Formation is characterized by the depositional facies of delta and lacustrine facies. The main rock types are feldspathic litharenite and lithic subarkose with low compositional and texture maturity. Based on the scanning electronic microscopy (SEM) and thin section observations, it … Lire la suite
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2015 — Inexact Two-Stage Fuzzy Chance- Constrained Programming for Water Resource Management under UncertaintiesRésumé
Yongxin County is located in the west of Jiangxi Province, China, within the middle reaches of the Heshui River Basin. The Heshui River provides the primary water resource for local economic activities. In recent years, there has been an increase in water demand in Yongxin County due to rapid economic development and rapid population growth. Water quality management has also been a major concern for local governments, which is not only affecting economic development but also threatening the sustainability of water resources. The local area has encountered local economic development problems with environmental concerns about water shortages and pollution. This … Lire la suite
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2012 — Automatic History Match and Upscaling Study of Vapex Process and Its Uncertainty AnalysisRésumé
Vapour Extraction (VAPEX) is a process to recover heavy oil by injecting vapourized solvent into a reservoir. In order to ensure successful commercial application of a VAPEX process, reliable prediction of VAPEX performance is crucial. The current practice for VAPEX performance prediction is using analytical scale-up methods that translate laboratory results to field applications with analytical models. However, the drawbacks associated with the analytical scale-up methods are that they only consider single phase flow and gravity drainage and cannot take reservoir heterogeneity into account, which limits the applicability to real field cases. In this work, an effort was made to … Lire la suite
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2017 — Simulation of free-surface flows and development of an improved particle methodRésumé
Undergoing development for decades, the mesh-free methods, both Smoothed Particle Hydrodynamics (SPH) and the Moving Particle Semi-implicit method (MPS), have become useful numerical tools for studying free-surface flows in various engineering problems. They are able to easily simulate complicated fluid interface flows. As a Lagrangian method, MPS with a weakly-compressible technique, Weakly-Compressible Moving Particle Semi-implicit method (WC-MPS), has been widely applied into handling free-surface flows in hydraulic engineering. WC-MPS has been reported to perform well in reproducing the flow structures and velocity distributions in many free-surface flows. One aspect of this study is to apply WC-MPS to simulate fishway flows … Lire la suite
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2019 — Lower Bounds and Algorithms for Searching NetworksRésumé
Research on graph searching has recently gained interest in computer science, mathematics, and physics. This thesis provides new results on two graph search models, namely fast searching and the zero-visibility cops and robber model. Given a graph that contains an invisible fugitive, the fast searching problem is to find the fast search number, i.e., the minimum number of searchers to capture the fugitive in the fast search model. This model was first introduced by Dyer, Yang and Ya¸sar in 2008. Although the literature provides a number of results on fast searching, many properties of the fast search number have not … Lire la suite
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2021 — Psychological Warfare in Vietnam: A Critical Evaluation of the U.S. Chieu Hoi Program, 1963-1971Résumé
During the Vietnam War, the United States launched a psychological warfare campaign that was unprecedented in size and scope for US military forces. Numerous programs were launched by the US in conjunction with the South Vietnamese government, with the goal of weakening North Vietnamese Army (NVA) and Viet Cong (VC) forces, by either lowering soldier morale, or inducing defections. The most prominent psychological program launched was the Chiêu Hồi program, which helped foster the defection of over 194,000 North Vietnamese forces. Despite this notable reduction of forces over the life of the program, from 1963 to 1971, it has been … Lire la suite