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2024 — Incorporating game theory with soft sets for better decision makingRésumé
Solving uncertainty is a challenge for decision-making. Soft set theory aims to aid complex decision-making when multiple uncertainty variables are involved. To solve classification problems with the existence of uncertainty, we adopted three-way classification instead of binary classification. It introduces a boundary region to handle scenarios in which a number of objects cannot be categorized as either positive or negative with a high degree of certainty. The three-way classification problem involves multiple experts. Each expert may produce a different three-way classification outcome based on their available information and expertise. We introduced a gametheoretic soft set model to address the fusion … Lire la suite
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2023 — Design optimization of sloshing tank using weakly compressible mesh free modelRésumé
In this study, the sloshing of the middle-baffled tank and non-baffled water tank under different external excitation frequencies and amplitudes. It was simulated and analyzed using the Weakly Compressible Moving Particle Explicit (WCMPE) method under condition of high-precision simulation data. Through the conversion of simulated data and images, the effects of baffle configuration, external excitation frequency and excitation amplitude, the effects of liquid sloshing were analyzed. The results showed that half-proportional baffles caused more complex liquid sloshing, which resulted in the dampening of the liquid slosh. On the other hand, it has been observed that the sloshing of the water … Lire la suite
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2013 — Development of GHG-Mitigation Oriented Models for the Planning of Integrated Energy-Environment Systems (IEES) Under UncertaintiesRésumé
Energy-related activities are a major contributor of anthropogenic greenhouse gas (GHG) emissions. The mitigation of GHG emissions should thus be incorporated within the framework of integrated energy-environment systems (IEES) planning. However, various uncertainties and dynamics of the systems pose difficulties for IEES planning. As well, variations associated with random weather/climatic conditions aggravate planning challenges. This dissertation aims to address such complexities through developing a series of inexact optimization models. The associated models include: (a) an interval multi-stage stochastic programming model (IMSP-IEES), (b) an interval fuzzy multi-stage stochastic programming model (IFMP-IEES), (c) a dual-interval mixed-integer linear programming model (DMLP-IEES), (d) a … Lire la suite
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2019 — A Numerical and Experimental Investigation of Wave Generated by Submerged LandslidesRésumé
The Weakly-Compressible Moving Particle Semi-implicit (WC-MPS) approach is applied to investigate the wave propagation and the flow fields from sliding blocks. Two bed inclined slope angles at 40° and 50° are used to obtain the experimental results. Existing studies have focused on an inclination slope of 45°. The characteristics of the free surface at the two specific angles of 40° and 50° have yet to be examined in detail, where 50° is the maximum angle in the experimentation. Sliding blocks are released under water and the top edges are parallel to the water surface. The simulation results are compared to … Lire la suite
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2013 — Phase Behaviour and Mass Transfer of Solvent(s)-CO2-Heavy Oil Systems Under Reservoir ConditionsRésumé
CO2 has been found to be an efficient agent for recovering heavy oil resources worldwide through an immiscible displacement process. One major disadvantage of CO2 immiscible process is the limited solubility of CO2 in heavy oil, resulting in limited enhanced oil recovery. Addition of light alkane solvents to CO2 stream may provide a better recovery efficiency of heavy oil, though it is not well understood how addition of solvents will affect the phase behaviour and mass transfer of CO2-heavy oil systems. Therefore, it is of fundamental and practical importance to study phase behaviour and mass transfer of the solvent(s)-CO2-heavy oil … Lire la suite
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2016 — Transient Pressure Modeling for CO2 Miscible Flooding ProcessesRésumé
Since CO2 flooding has been one of the most successful techniques for enhancing oil recovery, analyzing the pressure responses of CO2 injector is very important to understand the CO2 flooding performance and optimize the design and operation. The existing well test models of CO2 flooding have seen their limitation in accurately characterizing a miscible zone, e.g., negligence or over-simplification of the transient viscosity in the miscible zone. This study aims at establishing a comprehensive well testing model for a CO2 flooding process by incorporating a convection–diffusion mass transfer model with a transient pressure model. This thesis first compares four existing … Lire la suite
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2015 — Integrating PVT Properties for the Description of Well Responses in Gas Condensate ReservoirsRésumé
A gas condensate reservoir exhibits complex behaviors when the bottomhole pressure falls below the dew point pressure at a given reservoir temperature. When the condensate oil begins to drop out from the gas, a two-phase fluid system develops and a bank of condensate oil builds up, inducing severe productivity losses. While the production rate is constant, different mobility zones are formed around the wellbore corresponding respectively to the original-gas-in-place (OGIP) away from the well, the condensate bank with only gas flow, and two-phase gas and oil flow near the wellbore. Thus, the behaviors of gas condensate systems are complex and … Lire la suite
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2022 — Statistical-Based Hydrological Simulation and InferenceRésumé
Hydrological models have been used as essential tools for water resources planning and understanding the mechanisms in the water cycle. The rapid advance in information science and computational power in recent decades has encouraged hydrologists to solve water problems through data-driven approaches. To date, various statistical methods have been developed for hydrological simulation and inference (i.e., explain reasonings behind model response). However, many challenges arise from enormous uncertainties and complexities in the hydrological systems that greatly limit the usefulness of statistical models in terms of simulation accuracy and inference. Thus, there is a global need for advanced statistical models for … Lire la suite
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2015 — A Market-Based Arid-Region Water Resources Planning Model: Application to the Guhai Water Distribution System, ChinaRésumé
The arid regions in China, which own a pivotal position in national agriculture production, have confronted water supplying crisis triggered by the rapid growth of local economy. The Arid Zone of Ningxia Hui Autonomous Region (AZN) is one of the arid regions that severely suffer from water shortage. Since 1970s, local people has been relying on the water delivered from the Yellow River by water distribution systems, among which Guhai Water Distribution System (GWDS) is the largest and earliest one. Due to the limited capacity of GWDS and the decreasing precipitation caused by changing climate, the water availability in AZN … Lire la suite
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2015 — Targeted knockout of PpORS encoding an ancient type III polyketide synthase in the moss Physcomitrella patensRésumé
The ubiquitous presence of type III polyketide synthases (PKS) in the plant kingdom suggests their important roles in plant evolution. Among plant type III PKSs, PpORS from the model moss, Physcomitrella patens, has previously been suggested to closely resemble the most recent common ancestor of plant type III PKSs. In vitro analysis of PpORS revealed its function as a 2'-oxoalkylresorcinol synthase. PpORS is highly expressed in gametophores, but not in protonema. This, together with previous phytochemical analysis, suggested that in planta PpORS products may be incorporated into the moss cuticular structure to confer protection from environmental stresses. In this study, … Lire la suite
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2025 — Exploring Chinese EFL teachers’ use of translanguaging in the classroom: an ethnographic case studyRésumé
Translanguaging as a sociolinguistic theory and a pedagogy has captured the attention of language instructors in recent years, especially those working with culturally and linguistically diverse students. Most research on using translanguaging in teaching English has primarily been conducted in English as an Additional Language (EAL) context, particularly in the United States (see studies by Canagarajah, 2012; Carbonara & Scibetta, 2022; Creese & Blackledge, 2010; García & Kano, 2014). However, as a theory and pedagogy highly valued by language educators, its application should be extended to a broader context, reaching more diverse language learners. The literature suggests that translanguaging remains … Lire la suite
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2024 — Progressive partition-based granular computing and complexity measuresRésumé
Granular computing has received much interest over the past few decades due to its effectiveness and practicality in managing complexity. While it is intuitively believed that complexities in granular computing are linked to granularities, there do not exist any studies to show they have a direct connection. This suggests the need to investigate complexity from a different perspective. Simon’s concept of nearly decomposable systems, which describes complexity from a hierarchical perspective, aligns closely with the hierarchical nature of granular structures. Thus, granular structures can provide a foundation for exploring complexities in granular computing. This study investigates the complexity of the … Lire la suite
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2014 — Bivariate Log Location-Scale Model For Interval-Censored DataRésumé
Censored data is very common in survival analyses and experimental observations. In this thesis, I consider a selected bivariate model concerning censored data. I rst review three basic univariate models, leading to corresponding bivariate models, in more complicated forms. Also I will discuss the properties of an actual, selected bi- variate model with interval-censored data. Then, I would like to derive the likelihood form for bivariate data, and give the maximum-likelihood estimation of the parame- ters. At last, the results of some simulation work, using R, will be showed to verify whether my estimation method is good. Lire la suite
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2023 — Numerical simulation and optimization of cyclic and continuous fluid injection for geothermal energy recoveryRésumé
Geothermal energy is a viable solution for reducing greenhouse gas emissions and mitigating climate change. It has a wide geographic distribution, requires little exploration and operation costs, and has virtually no carbon emissions. This renewable energy source can generate electricity, provide direct heating and cooling, and even be utilized for agricultural and industrial processes. It can be harnessed at any scale, from individual buildings to large-scale power plants, and is available in many parts of the world. In addition, the operation and maintenance costs of geothermal energy resources are relatively low, making it a cost-effective alternative to other energy production … Lire la suite
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2015 — A Post-Fabrication Tuning Method for a Varactor-Tuned Microstrip Filter using the Space Mapping TechniqueRésumé
The RF (radio frequency) and microwave filter is of great importance in the most of the microwave applications which are widely used in broadcasting radios, televisions, radar techniques, telecommunications and satellite applications. Most of the microwave devices contain microwave filter blocks for transmitting and receiving Megahertz to Terahertz frequency band signals. The technologies in the fields of materials, fabrication, design method and electromagnetic analysis are developing quickly in recent years for RF applications. This thesis focuses on an important topic in microwave filter applications, post-fabrication filter tuning. Post-fabrication tuning processes become more and more important with the development of microwave … Lire la suite
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2021 — Tuning Techniques for Microwave Devices Based on Space Mapping and Surrogate ModelingRésumé
In a modern wireless communication system, with the development of various applications, microwave filters with stringent specifications and tunability start to receive more attention. Advances in novel materials, fabrication techniques, filter structures, tuning techniques, full-wave electromagnetic analysis methods, and computer-aided (CAD) design tools are proposed and delivered in the past 20 years. A designer can accurately model, simulate and optimize a filter structure with the use of different commercial software. Nevertheless, the experimental results from a fabricated filter usually give different performance compared to theoretical models and electromagnetic (EM) simulations due to many kinds of variations like fabrication process variation, … Lire la suite
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2020 — A Comparison Study of Carbon Dioxide Absorption Performance in MEA and Blended Amine Solvents for Post-combustion Process: Experiment, Modeling and SimulationRésumé
In recent years, industrialization causes excess carbon dioxide emissions. Carbon dioxide (CO2) is one of the main greenhouse gases due to human activities. However, high costs remain the main challenge to control the carbon dioxide from industry. Due to this issue, the carbon capture technique is developing slowly in most developing countries. This work is going to compare and explore a more effective blended amine solvent comparing with current common single amine solvents for the CO2 chemical absorption process for improving absorption performance and reducing the investment and operating costs. In this research, the CO2 absorption performance of aqueous MDEA/PZ … Lire la suite
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2024 — Promote the development of novel post-combustion CO2 capture technology towards practical and feasible: Design and assessment of solvents and process configurationsRésumé
This thesis focuses on developing novel CO2 capture processes that encompasses both CO2 absorption and solvent regeneration process. The work adhered to the guiding principle “Simplify complex system engineering towards practicality and feasibility”. This research aims not only to explore the enhancement of the state of art technologies in the CO2 capture industry but also to improve the potential for practical operations in pilot and industrial scale, ensuring it meets the general level of practical industrial application. Several experimental and simulation tasks have been accomplished in labs, including solvent screening tests, process configuration design, simulation studies, and bench-scale pilot plant … Lire la suite
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2017 — Exclusive Backward-Angle Omega Meson ElectroproductionRésumé
Exclusive meson electroproduction at different squared four-momenta of the exchanged virtual photon, Q^2 , and at different four-momentum transfers, t and u, can be used to probe QCD’s transition from hadronic degrees of freedom at the long distance scale to quark-gluon degrees of freedom at the short distance scale. Backward-angle meson electroproduction was previously ignored, but is anticipated to offer complimentary information to conventional forward-angle meson electroproduction studies on nucleon structure. This work is a pioneering study of backward-angle omega cross sections through the exclusive 1H(e, e′ p)omega reaction using the missing mass reconstruction technique. The extracted cross sections are … Lire la suite
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2012 — Heavy Gas Cherenkov Detector Construction for Hall C at Thomas Jefferson National Accelerator FacilityRésumé
The Thomas Jefferson National Accelerator Facility (JLab) has undertaken the 12 GeV Upgrade to double the accelerating energy of its electron beam. This attracts many interesting proposals to probe the quark-gluon nature of nuclear matter at higher energy, therefore a new set of equipment is required. Experimental Hall C of JLab has planned to construct a new Super High Momentum Spectrometer (SHMS) to replace the existing Short Orbit Spectrometer (SOS). The University of Regina is assigned to construct the Heavy Gas Cˇ erenkov (HGC) Detector as part of the SHMS focal plane detectors. This detector will be used as critical … Lire la suite
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2015 — Phase Behaviour of Alkane Solvent(s)-CO2- Water-Heavy Oil Systems at High Pressures and Elevated TemperaturesRésumé
As for enhanced oil recovery (EOR) methods in heavy oil reservoirs where the existing techniques find their limits, the solvent-based techniques have attracted extensive attentions recently. CO2 is found to be a prevailing solvent due to its superiority of diluting heavy oil as well as its potential of mitigating greenhouse gas emissions, though its solubility is limited in heavy oil. The addition of light hydrocarbon solvent(s) (e.g., C3H8 and n-C4H10) in CO2 stream facilitates its dissolution in heavy oil, resulting in an enhanced viscosity reduction and swelling effect. Furthermore, water exists in the reservoir not only as the formation water … Lire la suite
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2022 — Generalized fiducial inference on the means of zero-inflated Binomial and Binomial hurdle modelsRésumé
The zero-inflated binomial and binomial hurdle models are two models to address the problem of excess zeros for proportional data. Both model structures are similar, which are composed of two distributions. A degenerate process is responsible for producing zeros, which are called structural zeros. The other distribution could be a binomial or zero truncated binomial distribution which depends on the type of model in this study. Zero-inflated binomial (ZIB) model involves the sampling zeros. On the other hand, binomial hurdle(BH) model address the structure zeros only in the zero-inflated part, which is a difference between the two models. Generalized fiducial … Lire la suite
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2017 — Pretreatment of Oilfield Produced Water using Ionic Liquids for Dissolved Air FloatationRésumé
Energy consumption is rising due to population increase and industry development. There will be an increase of nearly 66% of energy consumption related to fossil fuel such as oil and gas between 2003 and 2030 from 7.6*1013 to 12.6*1013 kilowatt-hours worldwide. With the increase in the production of oil and gas, a larger amount of produced water (PW) will be generated. Produced water poses a risk to the environment, because it contains persistent toxic and carcinogenic constituents. The dissolved air floatation (DAF) process is the most widely used technique in the world for produced water treatment. In order to reach … Lire la suite
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2024 — Investigating the role of water and nanoparticles in the performance of CO2 and ethane-based cyclic solvent injection process for heavy oil recoveryRésumé
Cyclic solvent injection (CSI) process is a promising method for enhancing heavy oil recovery in thin or deep heavy oil reservoirs. Foamy oil flow is a major phenomenon of the CSI process, but the impact of foam stabilizers like nanoparticle and water on its performance has not been well understood. Therefore, an in-depth understanding of waterflooding and nanoparticle affecting CSI performance is a crucial step toward further enhancing oil recovery. In addition, most studies only focus on one method. In fact, in order to develop an oil reservoir cost-effectively and efficiently, a variety of methods have to be applied in … Lire la suite