Browsing by Author "Azam, Shahid"

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Open Access
Adaptive Neuro-Fuzzy Inference Systems (ANFIS) - Based Model Predictive Control (MPC) for Carbon Dioxide Reforming of Methane (CDRM) in a Plug Flow Tubular Reactor for Hydrogen Production
(Faculty of Graduate Studies and Research, University of Regina, 2013-01) Essien, Ememobong Ita; Ibrahim, Hussameldin; Mehrandezh, Mehran; Idem, Raphael; Shirif, Ezeddin; deMontigny, David; Azam, Shahid
The current sources of our energy supply are plagued with many problems, and the impact on the climate is of grave concern. To preserve and sustain our environment, a non-polluting and renewable energy source is required. Hydrogen (H2), when extracted from one of its many sources during carbon dioxide (CO2) capture, is considered a non-polluting, efficient and environmentally sustainable energy source. In this research work, the control of a pilot-scale reformer for the production of hydrogen was studied. Hydrogen was produced through the carbon dioxide reforming of methane (CDRM). This process was used to convert methane (CH4) and carbon dioxide into hydrogen. A high methane conversion was maintained by controlling the temperature in the reformer at the thermodynamically desired level. The control strategy applied to this process was the model predictive control (MPC) based on an adaptive neuro-fuzzy inference system (ANFIS) model. MPC has, among other advantages, the ability to predict the response of the system over a given prediction horizon. Experimental results showed that the ANFIS model was able to accurately replicate the response of the process to changes in temperature. Based on the ANFIS model, an MPC strategy was formulated for the process.
Open Access
Characterization and Behaviour of Clayey Slurries
(Faculty of Graduate Studies and Research, University of Regina, 2016-12) Ito, Maki; Azam, Shahid; Hussein, Esam; Chi, Guoxiang; Veawab, Amornvadee; Bussiere, Bruno
The purpose of this research is to develop a fundamental understanding of the characteristics and behaviour of clayey slurries. A comprehensive research methodology consisting of laboratory investigations and computational analyses was adopted. A clayey slurry (uranium leach residue) was selected from the extraction process to capture the distinct slurry features at the onset of deposition. The practical impact of this research is that the investigated slurry (new waste stream) exhibited various components of settling that are important for developing depositional plans and determining storage capacity of the containment facility. Likewise, the scientific contribution is the understanding that solid-liquid composition influences settling of clayey slurries such that the effects are dominant during sedimentation and the initial phase of consolidation. More importantly, the conceptual model of flow through settling clayey slurries confirms that Poiseuille’s law of water flow through porous media is applicable to this class of materials in the transition zone between sedimentation and consolidation. The slurry (containing 28% clay size) comprised both non-clay minerals (46% muscovite and 30% quartz) and clay minerals (8% illite, 5% chlorite and 2% kaolinite) and acidic pore water with large amounts of SO42- (22600 mg/L) and Mg2+ (1340 mg/L). Settling occurred through sedimentation (25% to 35% initial solids) and consolidation (40% to 50% initial solids). The average hydraulic conductivity during sedimentation reduced from 3.0 x 10-6 m/s to 5.3 x 10-8 m/s along with a void ratio reduction from 7.4 to 2.6. Likewise, volume compressibility during consolidation showed apparent pre-consolidation at low effective stress (0.3 kPa to 2 kPa) with a reduction in void ratio from 2.6 to 2.5. The hydraulic conductivity during consolidation decreased from 2.6 x 10-9 m/s (at e = 2.6) to 2.0 x 10-10 m/s (at e = 2.1). An image analysis method was developed to identify and quantify slurry constituents and to determine and validate index properties and hydraulic conductivity. It was found that the investigated clayey slurry comprised of free water, hydrated grains, and solids. The proposed solids ratio successfully separated the hydrated solids into water and solids thereby allowing an accurate and precise determination of index properties through image analysis (R2 ≥ 0.90). Likewise, the modified definition of hydraulic radius (average pore throat area divided by average perimeter of pore) adequately described the water flow mechanism through clayey slurries because pore area outside of the pore throat does not contribute to water migration. Furthermore, the proposed RH definition is independent of spatial distribution of pores and, as such, precludes the use of tortuosity in determining hydraulic conductivity.
Open Access
Characterization and Centrifuge Dewatering of Oil Sands Fine Tailings
(Faculty of Graduate Studies and Research, University of Regina, 2013-08) Rima, Umme Salma; Azam, Shahid; Henni, Amr; Ng, Kelvin Tsun Wai; Cheema, Tariq
Oil sands mining operations in northern Alberta, Canada generates an ever growing volume of fine tailings that are disposed off hydraulically in the tailings ponds. The caustic extraction process results in dispersed tailings that do not dewater under conventional gravity settling. Centrifugation along with polymer addition has recently demonstrated promising results for these tailings at the pilot-scale level. The complex colloid-water-polymer interactions govern the dewatering behaviour of the tailings during this process. The main objective of this research was to characterize and improve the dewatering properties of oil sands fine tailings using centrifuge technology in conjunction with polymer amendment. MFT was found to be a fine grained material with clay size fraction of 53% and possessing a moderate water adsorption capacity (wl = 55% and wp = 25%). The solids comprised of 55% quartz and 40% clay minerals (kaolinite and illite) and showed a specific surface area of 43 m2/g and a cation exchange capacity of 29 cmol(+)/kg. Likewise, the pore water was dominated by Na+ (776 mg/L) and HCO3 - (679 mg/L), related to the extraction process and by Cl- (518 mg/L) and SO4 2- (377 mg/L), related to ore geology. A basic pH (8.15), a high EC (3280 μS/cm), and a high ZP (-46 mV) indicated a dispersed MFT microstructure. Centrifugation improved MFT dewatering through the physical mechanisms of particle segregation, assemblage formation, and flow channeling. For the investigated g-factor of up to 2550 g, the released water increased by 4.7%, the entrapped water decreased by 30% and the sediment solids content increased by 7%. The corresponding decrease in pH was from 8.15 to 7.2, EC from 3295 μS/cm to 2530 μS/cm, and ZP from -40 mV to -28.7 mV. These data confirmed aggregate formation and an effective capture of clay particles mainly in the intermediate suspension zone. Centrifugation along with polymer amendment was found to improve MFT dewatering up to 630 g (because of assemblage formation due to increased particle collisions and polymer adsorption) beyond which dewatering declined (owing to floc breakage due to excess centrifugation and surface saturation). For 10 mg/L polymer, the released water increased by 17%, the entrapped water decreased by 58% and the sediment solids content increased by 13%. The corresponding values at 20 mg/L were found to be 34%, 82%, and 18%, respectively. The physicochemical parameters were found to correlate well with tailings dewatering. The decrease in pH, EC, and ZP up to 630 g is due to water dilution, charge neutralization, and shear plane displacement, beyond which opposite phenomena occurred. At the optimum and 10 mg/L polymer, the pH value decreased to 7.5, EC decreased to 2615 μs/cm, and ZP decreased to -26 mV. The corresponding values at 20 mg/L were found to be 7.5, 2234 μs/cm, and -21 mV, respectively.
Open Access
Chloride Salts Removal by non Planted Constructed Wetlands Receiving Synthetic Brines from Belle Plaine Potash Mining
(Faculty of Graduate Studies and Research, University of Regina, 2015-03) Chairawiwut, Warawut; McMartin, Dena; Azam, Shahid; Ng, Kelvin Tsun Wai; An, Chunjiang; Gilles, Jon
Four pilot-scale constructed wetlands (CWs) were employed to study the fate and transport of the two dominant chloride salts (NaCl and KCl) receiving the synthetic brine. The characteristics of the brine solution are made up with a 10:1 concentration ratio between NaCl and KCl based on data obtained from Belle Plaine potash mine site. The multi-layer soils were designed to function as a main salt filtering component comprising of Regina Clay (grain size <0.002 mm), Brick Sand (grain size <4.75 mm) and sharp gravels (grain size between 6.3-19.1 mm) despite the clay layers contained a poor compact condition (Db =1.4, <1.6 g/cm3). The volume of void space in the compacted clay was reduced to approximately half the natural state following application of pressure (4,505 cm3 to 2,743 cm3). The CW systems were operated by the 16-day format (batch 1-3) and the 4-day format (batch 4). During the 16-day format experiments, the best K+ removal rate was recorded on Cell2 as 92.1±63.4% (4.6±5.3mg/l) while Cell 4 contributed the maximum removal of Na+ and Cl- as 44.8±76.7% (53.2±92.4mg/l) and 50.5±109.6% (85.3±184.3.4mg/l). In the 4-day format operation, the chloride breakthrough curve was discovered in all treatment CW cells, excluding the control. Moreover, the curve stated at less than 6 hours (C/C0 > 0.05) and approximately reached the break point (C/C0 > 0.95) after passing 48 hours. Then the clay media was exhausted and lost its ability to remove Cl-. However, the study was not able to determine the breakthrough curves in neither Na+ nor K+ cases during batch experiment 4 due to unidentified ending points on both cations.
Open Access
Controlled photogrammetry system for determination of volume and surface features in soils
(Elsevier, 2021-04-28) Suchan, Jared; Azam, Shahid
Quantitative and qualitative determination of total volume and surface features of a soil specimen is important in geotechnical engineering. Available methods suffer from a variety of shortcomings such as sample disturbance, equipment calibration, and lack of precision. The Controlled Photogrammetry System (CPS) is based on Structure-from-Motion (SfM) to capture a series of photographs and transform the images into a referenced three-dimensional model.
Open Access
Corrosion Evaluation for Absorption - Based CO2 Capture Process Using Single and Blended Amines
(Faculty of Graduate Studies and Research, University of Regina, 2012-09) Gunasekaran, Prakashpathi; Veawab, Amornvadee; Azam, Shahid; Aroonwilas, Adisorn; Torabi, Farshid
One of the major problems associated with the amine-based carbon dioxide (CO2) capture process is corrosion of process components, which results in unexpected downtime, production loss, and even major fatalities. Most of the published corrosion literature is on conventional monoethanolamine (MEA) solvent, and there have been very few corrosion studies conducted on other single amines like methyldiethanolamine (MDEA), diethanolamine (DEA), 2-amino-2-methyl-1-propanol (AMP), and some blended amines. Although there has been extensive research conducted on the kinetics of concentrated piperazine (PZ) as an attractive solvent for the CO2 absorption process, no corrosion studies have been conducted for this solvent. This work investigated the corrosion of construction materials including carbon steel (CS1018) and stainless steels (SS304 and SS316) in the CO2 capture process, using various types of CO2 absorption solvents. The tested solvents included MEA, DEA, MDEA, AMP, PZ, and their blends. A series of laboratory corrosion tests was carried out using electrochemical techniques (DC-cyclic potentiodynamic polarization and ACimpedance measurement) and weight loss technique to establish an engineering corrosion database for the CO2 capture process. Experimental conditions were chosen to be CO2 saturation and 80°C for most experiments. The electrochemical results show that the corrosivity order of CS1018 for the single amine systems was MEA > AMP > DEA > PZ > MDEA. The corrosion rates in MEA and AMP systems were almost double those of the PZ and MDEA systems. The passivation of carbon steel in the DEA system was more compact and less porous than those in the MDEA, PZ, MEA, and AMP systems. The corrosive effects of process contaminants, i.e., thiosulfate, oxalate, sulfite, and chloride, on corrosion rate were observed in all amine systems. The presence of thiosulfate reduced the corrosion rate of carbon steel in the MEA system, whereas the presence of oxalate increased the corrosion rate in all tested single amines. Two corrosivity behaviours were found in the presence of sulfite and chloride. In the presence of sulfite, the corrosion rate of carbon steel was increased in the MEA, DEA, MDEA, and PZ systems, but decreased in the AMP system. In the presence of chloride, the corrosion rate increased only in the MDEA system, but decreased in the MEA, DEA, AMP, and PZ systems. In addition to single amines, five different blended amines were also tested for their corrosiveness. The results show that the corrosivity trend of CS1018 in blended amine systems was MEA-PZ ≥ MEA-AMP ≥ MEA-MDEA > MDEA-PZ > AMP-PZ. The stainless steel materials (SS316 and/or SS304) offered great resistance to corrosion in all amine systems. For example, the corrosion rates were very low, in the range of 0.006 - 0.036 mmpy, which is well below the standard acceptable corrosion rate (0.07 mmpy). Conductivity of the solution was found to correlate well with corrosion rate in both single and blended amine systems. The weight loss results show that after 28 days, the corrosivity order of CS1018 in single amine systems was MEA > DEA > PZ > AMP ≈ MDEA. The corrosion products deposited over carbon steel were found to be iron carbonate (FeCO3) and iron oxide (Fe3O4).
Open Access
Datasets for the Determination of Evaporative Flux from Distilled Water and Saturated Brine Using Bench-Scale Atmospheric Simulators
(Multidisciplinary Digital Publishing Institute, 2021-12-22) Suchan, Jared; Azam, Shahid
Evaporation from fresh water and saline water is critical for the estimation of water budget in the Canadian Prairies. Predictive models using empirical field-based data are subject to significant errors and uncertainty. Therefore, highly controlled test conditions and accurately measured experimental data are required to understand the relationship between atmospheric variables at water surfaces. This paper provides a comprehensive dataset generated for the determination of evaporative flux from distilled water and saturated brine using the bench-scale atmospheric simulator (BAS) and the subsequently improved design (BAS2). Analyses of the weather scenarios from atmospheric parameters and evaporative flux from the experimental data are provided.
Open Access
Depositional and Dewatering Behaviour of Uranium Mill Tailings
(Faculty of Graduate Studies and Research, University of Regina, 2014-08) Bhuiyan, Md. Imteaz Ferdoush; Azam, Shahid; Ng, Tsun Wai Kelvin; Shirif, Ezeddin; Ibrahim, Hussameldin
The Key Lake operation in Saskatchewan, Canada, is the largest uranium mill in the world. This mill process generates tailings that are deposited into an onsite storage area called the Deilmann Tailings Management Facility (DTMF). An effective tailings management scheme requires a clear understanding of slurry behaviour throughout the life-cycle, starting from production thorough the deposition to dewatering in the storage facility. The main objective of this research was to investigate the depositional and dewatering behaviour of uranium mill tailings (4%, 5%, and 6% mill tailings) from the Key Lake operation under laboratory and field conditions. All of the samples exhibited the same trend for yield strength development during the tests for rheological properties. A negligible strength (0.4 kPa) was found to have at 60% solids content (s) followed by a rapid increase thereafter. The settling and segregation tests were performed under different initial solids contents (si). The 4% mill tailings exhibited a lower rate and total amount of settlement than 5% and 6% mill tailings in the settling tests. The initial hydraulic conductivity (ki) decreased by two orders of magnitude (10-2 m/s to 10-4 m/s) with a decrease in initial void ratio (ei) from 16 to 4 (15% < si < 40%) and a decrease in final void ratio (ef) from 8 to 4 (30% < si < 45%) such that 4% mill tailings showed one order of magnitude lower values than the 5% and 6% mill tailings. The corresponding settling potential (SP) decreased ten times (50% to 5%) for 4% mill tailings and four times (60% to 15%) for 5% and 6% mill tailings. The effective stress (σ') increased from 80 Pa to 260 Pa in the settling tests. The average solids content after settling was 35% (20% < s < 42%) for 4% mill tailings, 40% (15% < s < 60%) for 5% mill tailings, and 39% (18% < s < 54%) for 6% mill tailings with a corresponding normalized solids content deviation of ±3%, ±8%, ±6%, respectively. The 4% tailings were less prone to segregation when compared with 5% and 6% tailings. Nevertheless, all materials were essentially non-segregating at 40% initial solids content. The large strain consolidation tests were conducted by using a customized and fabricated consolidation test system. During the tests, the total strains were 31% to 42% for all investigated mill tailings in an effective stress range of 0.3 kPa to 8 kPa. The change in void ratio was higher for 4% mill tailings (Δe = 2.5) than 5% and 6% mill tailings (Δe = 1.3 to 1.7). The lowest measurable effective stress was 0.3 kPa for all investigated mill tailings. The void ratios were found to be 3.8, 3.1, and 3.4 at σ' of 1 kPa and further reduced to 3.3, 2.8, and 3.1 at σ' of 8 kPa for 4%, 5%, and 6% mill tailings. The k values showed an initial scatter before attaining a steady value and were found to range from 10-7 m/s to 10-8 m/s. The test results provided the volume compressibility and hydraulic conductivity relationships for current (4%) and future (5% and 6%) mill tailings. The large strain consolidation behaviour in the DTMF was investigated by analyzing survey data from 1996 to 2008, laboratory testing of the current (4%) mill tailings, and history matching of the deposited tailings using numerical modeling. The numerical modeling results closely approximated the consolidated tailings elevations and effective profiles in the DTMF over the period of 1996 to 2008. The field effective stress values correlated quite well with the modeling results thereby validating the predictions. Overall, the results indicate that the effective stress increased from 0 kPa at the surface to the following values at the DTMF bottom: 200 kPa in 1999, 530 kPa in 2005, and 680 kPa in 2008.
Open Access
Design of an Over-Coupled Coaxial Resonator for Determing the Electrical Properties of Materials
(Faculty of Graduate Studies and Research, University of Regina, 2017-09) Suleman, Muhammed Bashiru; Laforge, Paul; Al-Anbagi, Irfan; Azam, Shahid; Gelowitz, Crag
knowledge so that different materials can be adapted for varying purposes. For example, materials used in engineering design and processes. With unique properties of every material, there is need to determine the properties and characterise materials based on their properties, where their electrical properties is dependent on the dielectric properties of the materials. In this thesis, a method used in determining the electrical properties of materials using the group delay information is investigated. A gap-coupled coaxial resonator that operates in an over-coupled state is designed and used in obtaining the dielectric properties of sample materials. Electromagnetic and circuit simulation tools (HFSS and ADS) are used to better understand and develop the concepts used in this study. Simple lumped elements and distributed elements are used in ADS to model coupled resonators so as to arrive at a set of equations to characterise the coupled resonator when it is empty and filled with a dielectric sample. With HFSS, a model of gap-coupled coaxial resonator is designed and analysed. Where the gap provides the capacitance required for coupling electromagnetic field into the resonator. Different known values of dielectric constant are tested and evaluated using the set of equations obtained. The results from the simulations are used to arrive at certain design parameters for fabricating the resonator. With the physical resonator, Teflon is tested to determine its electrical properties. The results from both the simulation and the fabricated resonator show dielectric constant and loss tangent values obtained to be within the known limits of Teflon.
Open Access
Determination of evaporative flux from water and soil surfaces
(Faculty of Graduate Studies and Research, University of Regina, 2023-02) Suchan, Jared Joseph; Azam, Shahid; Xue, Jinkai; Azadbakht, Saman; Chi, Guoxiang; Gurrapu, Sunil
The Canadian Prairies has the highest water demand-to-availability ratio in Canada. The region is characterized by a scarcity of water resources because evaporation generally exceed precipitation. Evaporation is a complex phenomenon based on interactions between meteorological and physiological factors. The purpose of this research was to accurately determine evaporative flux from water and soil surfaces. The main research contributions of this research are summarized as follows: (i) a Bench-scale Atmospheric Simulator (BAS/BAS2) was developed to control artificially generated parameters for short time periods; (ii) a Controlled Photogrammetry System (CPS) using Structure-from-Motion (SfM) technology was developed for accurate and non-destructive measurement of dimensional changes during evaporation; (iii) high-quality evaporation datasets were developed for calibration of devices, validation of prediction equations and evaluation of theoretical frameworks; (iv) predictive models for evaporation from water were evaluated to select appropriate empirical equations for predicting potential evaporative flux from water; and (v) a theoretical framework for evaporation from soils was developed to correlate with soil behavior (water retention and soil shrinkage) for both fresh water and saline water. The findings of this research are useful for developing methods to minimize evaporation and for helping with devising water use policy.
Open Access
Determination of Evaporative Fluxes Using a Bench-Scale Atmosphere Simulator
(Multidisciplinary Digital Publishing Institute, 2021-01-01) Suchan, Jared; Azam, Shahid
An accurate determination of evaporative fluxes is critical for efficient water management in semi-arid climates such as in the Canadian Prairies. The main achievements of this research are the design and operation of a bench-scale atmosphere simulator, performance evaluation using selected weather scenarios pertaining to regional atmospheric conditions, validation using established empirical correlations, and estimation of evaporation rates and the amount for a typical local water body. Results indicate that the measured data achieved the target values for the various parameters and the data were found to be stable during the 3-h test duration. The vapour flux was found to have large variation during summer (0.120 g∙s−1∙m−2 during the day and 0.047 g∙s−1∙m−2 at night), low variation during spring (0.116 g∙s−1∙m−2 during the day and 0.062 g∙s−1∙m−2 at night), and negligible change during fall (0.100 g∙s−1∙m−2 during the day and 0.076 g∙s−1∙m−2 at night). The measured vapour flux was generally within one standard deviation of the equality line when compared with that predicted by both the mass-transfer equations and the combination equations. The average evaporation ranged from 4 mm∙d−1 to 8 mm∙d−1 during the day and decreased to 1 mm∙d−1 to 3 mm∙d−1 at night. The 24-h evaporation was found to be 8 ± 1 mm∙d−1 from late April through late October. Likewise, the cumulative annual evaporation was found to be 1781 mm, of which 82% occurs during the day and 18% at night.
Open Access
Development of BAS2 for determination of evaporative fluxes
(Elsevier, 2021-06-24) Suchan, Jared; Azam, Shahid
Accurate determination of evaporative flux from water surfaces and liquid containing porous media is critical for geotechnical and geoenvironmental applications. Laboratory simulations can isolate the various parameters influencing evaporative fluxes. However, most simulators capture selected surface and atmospheric conditions, and published literature generally provide limited information on the development and operation of the instruments. The new simulator adequately captures a wide range of relevant field parameters, maintains controlled conditions over the required testing time, utilizes readily available components for modular fabrication, and facilitates operational efficiency between individual modules.
Open Access
Development of Fractional Programming Methods for Environmental Management Under Uncertainty
(Faculty of Graduate Studies and Research, University of Regina, 2016-09) Wang, Shudong; Huang, Guo (Gordon); Azam, Shahid; An, Chunjiang
Rapid economic development and population growth has accelerated environmental degradation and resource scarcity. There is growing recognition of the importance of environmental conservation and sustainable development. Sustainable environmental management may benefit from integrating a variety of factors into decision-making processes, such as economic, environmental, social, technical, legislative, and political considerations. Moreover, environmental systems are often involved in a multitude of uncertainties, which significantly intensifies the complexity of systems analysis. In this thesis, a set of fractional programming methods are developed to solve multiobjective environmental management problems under uncertainties. Factorial analysis is introduced to explore the interactions of uncertain system parameters and quantify their interactive effects on system performance. The proposed methods include (1) an inexact fractional credibility-constrained programming method for sustainable municipal solid waste management, (2) a generalized fuzzy fractional programming method for air quality management, and (3) an inexact mixed-integer sequential factorial fractional programming method for sustainable municipal solid waste management in the City of Regina, Canada. The models can reflect the multi-objective characteristic of environmental management and address the conflicts between economic and environmental objectives without weighing them. The proposed models are able to maximize environmental benefits and obtain maximum system efficiency with minimal system costs. The objective is to optimize the ratio of environmental benefits to system costs rather than considering them separately, which provides a practical way to solve efficiency issues in environmental management. Moreover, the interactions obtained with factorial analysis may reveal implicit interrelationships between uncertain parameters and help decision makers gain insight into a complex environmental system.
Open Access
Development of GHG-Mitigation Oriented Models for the Planning of Integrated Energy-Environment Systems (IEES) Under Uncertainties
(Faculty of Graduate Studies and Research, University of Regina, 2013-08) Li, Gongchen; Huang, Guo H.; Azam, Shahid; Zeng, Fanhua (Bill); Yang, Boting; Wu, Wanli
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 dual-interval multi-stage stochastic programming model (DMSP-IEES), (e) a fuzzy dual-interval multi-stage stochastic programming model (FDMSP-IEES), (f) a joint-probabilistic left-hand-side chance-constrained programming model (ILJCP-IEES), (g) an interval joint-probabilistic two-side chance-constrained programming model (IJTCP-IEES), and (h) an interval fuzzy two-side chance-constrained programming model (IFTCP-IEES) for energy systems planning and GHG-emission mitigation in Alberta. The main contribution of this research is the development of a series of innovative approaches for supporting robust planning of regional energy systems and scientific reduction of GHG emissions under uncertainties. The IMSP-IEES and IFMP-IEES improved upon the previous inexact optimization methods by allowing the stochastic uncertainties and dynamics within a multi-layer scenario tree to be incorporated within the planning systems. The integration of fuzzy programming further enhanced the robustness of IEES optimization through addressing the ambiguous system information. The DMLP-IEES, DMSP-IEES and FDMSP-IEES introduced the concept of dual interval into IEES planning to address dual uncertainties without distribution information but rough estimation of lower and upper bounds. The proposed methods have advantages in integrating inherent system uncertainties expressed not only as discrete intervals and dual intervals but also as possibility and probability distributions into solution procedures. The ILJCP-IEES, IJTCP-IEES and IFTCP-IEES enhanced the capabilities of previous inexact stochastic optimization approaches in dealing with left/two-side multi-randomness issues, especially when a joint-probabilistic requirement is imposed on multiple constraints. Through integrating interval and fuzzy programming, the three universal types of inexact information could be addressed and thus further enhance the robustness of the IFTCP-IEES. The IFTCP-IEES was then applied to GHG-emission reduction and energy system planning in Alberta. Results indicated that interactions among various system components would be sufficiently reflected in a mixed multi-uncertain environment.
Open Access
Dewatering Behavior of Centrifuged Oil Sand Fine Tailings for Surface Deposition
(Faculty of Graduate Studies and Research, University of Regina, 2013-12) Owolagba, John Oladele; Azam, Shahid; Jin, Yee-Chung; Shirif, Ezeddin; Ibrahim, Hussameldin
Tailings footprint reduction efforts have led to the investigation of several treatment technologies (natural, physical, chemical and physicochemical processes) to improve tailings dewatering. Most of these methods develop slurries with solids content ranging between 50% and 60% (Devenny, 2010). However, this solids content is not enough because the material cannot be readily reclaimed as a soil. The required improvement is achieved through subsequent dewatering in the disposal facility by evaporation that, in turn, is governed by the prevalent climate. Centrifuge technology is being adapted as part of long time management of oil sand fine tailings. The main objective of this research was to investigate the dewatering behavior of centrifuged oil sand fine tailings for surface deposition using laboratory investigation program and numerical modeling. A material with 60% solids (e = 1.5) was obtained using a bench-scale centrifuge. The fine grained material (52% clay fraction) with a moderate water adsorption capacity (wl = 40% and wp = 20%) indicated an air entry value of 1000 kPa and a residual suction of 30000 kPa. The correct way of representing the soil water characteristic curve for tailings was found to be the one based on degree of saturation along with simultaneous volume change measurements. The tailings mainly dewatered during normal shrinkage while remaining saturated whereas volume reduction was negligible beyond the shrinkage limit. Likewise, dewatering under an effective stresses of 160 kPa was found to be 67% along with a compression index of 0.36. The saturated hydraulic conductivity measured 3 x 10-10 m/sec that decreased marginally during consolidation and rapidly (10- 10 m/sec to 10-18 m/sec) due to suction. The unsaturated soil properties and the atmospheric parameters were fully coupled using one-dimensional seepage model. Volume decrease due to desiccation was also investigated by correlating laboratory measured shrinkage with model results. The model predicted results were found to largely depend on how the material properties were quantified, site condition and the applied atmospheric forcing parameter. Cyclic variations in the degree of saturation under different climatic scenario decreased over the summer months. The driest condition showed degree of saturation of 50% corresponding to a suction 5000 kPa and solids content of 78%. Whereas the mean condition showed a degree of saturation of 70% corresponding to a suction of 2500 kPa and a solids content of 72%. While wettest condition showed a degree of saturation of 89% corresponding to 700 kPa matric suction and a solids content of 67%. These results were significantly impacted with increasing depth. Most predicted variations narrowed down such that the curves converge at 6 m depth. The top 4 m was found to be the active zone of soilatmosphere interactions therefore, a 4 m annual surface deposition will be most appropriate for this class of material. A minimum settling potential of 8% was observed. The one dimensional nonlinear finite strain consolidation model successfully captures the self-weight dewatering behavior of centrifuged oil sand fine tailings due to homogenous nature. The consolidation process was highly influenced by the initial tailings treatment resulting in high solids content. This initial condition (s = 60%) makes these tailings behave more like a soft soil. Pore water pressure dissipation was so small in one year that no significant compression occurred resulting in relatively small gain in effective stress. Similarly, volume compressibility and initial solids was found to be responsible for the amount of consolidation resulting in negligible reduction in void ratio and relatively small increases in solids content.
Open Access
Dewatering Behaviour of Clay Slurries
(Faculty of Graduate Studies and Research, University of Regina, 2017-01) Khan, Faseel Suleman; Azam, Shahid; deMontigny, David; Velez, Maria; Huang, Gordon
The main objective of this research was to develop a fundamental understanding of the dewatering behaviour of clay slurries. A comprehensive research methodology was developed to understand the natural dewatering processes of consolidation, desiccation and consolidation-desiccation. Laboratory investigation methods were improved, data analysis techniques were enhanced, and numerical methods were customized. An active clay slurry was prepared at different initial conditions (3 LL to 1 LL) to mimic field conditions ranging from a thin slurry to a paste-like consistency. Thin samples were used in a conventional oedometer test and in the evaporation test. A correlation was developed between the oedometer test and the bench-top centrifuge test to describe slurry consolidation. Likewise, the instantaneous profile method was applied to thin samples resulting in avoiding the need of instrumentation in evaporation tests. The small-strain consolidation theory was customized to predict large-strain consolidation deformations and diffusion equation was used to simulate desiccation. The use of effective stress and soil suction as state variables was found suitable for clay slurries. A consolidation-desiccation framework was developed to identify the governing dewatering processes operative within a slurry deposit. This research produced useful laboratory test methods, which can be implemented at on-site laboratories for determining the consolidation and desiccation properties of clay slurries. Similarly, the improved understanding of the significance of initial conditions (suspension to a paste-like consistency) on slurry dewatering is important to develop material-specific tailings deposition schemes. Finally, an understanding of the governing dewatering processes is useful to develop site-specific tailings management strategies.
Open Access
Dielectric characterization of materials and lossy filter design using reflected group delay
(Faculty of Graduate Studies and Research, University of Regina, 2024-12) Walia, Gaurav; Laforge, Paul; Wang, Zhanle (Gerald); Azam, Shahid; Teymurazyan, Aram; Zarifi, Mohammad Hossein
Filters play a significant role in different types of communication systems such as radars, cellular mobile and satellite communication. They are helpful in improving the performance of a communication system by restricting the transmission to the intended frequency band and rejecting the interfering signals from outside. Filters are expected to provide distortion free transmission to the signals in the passband and thus require flat in-band response and an adequate amount of out-of-band rejection. Filter technologies employing coaxial, waveguide and dielectric resonators can meet these requirements but at the cost of large size. Low loss in these filter technologies can be identified by their high quality factor (Q-factor). Higher insertion loss (lower Q-factor) in the filter response is acceptable based on the communication system using that filter and its position in that system. Filter design must deal with the electrical and physical specifications based on the required filter response. The concept of lossy filter is based on the fact that loss in a filter is distributed among the various resonators in a way that helps to achieve flat in-band response. This is achieved at the cost of degraded insertion loss. In this way, lossy filters provide an effective solution to the applications that can afford low Q-factor and higher insertion loss. Resonator is a building block in a filter network and a good understanding of resonators is quite useful in developing an insight of a filter network. Resonators also have a good deal of applications in methods used to perform dielectric characterization of materials. Keeping this connection of resonators and filter in view, the initial research presented in this thesis is focused on lossy resonators. This was helpful in developing some methods for dielectric characterization of materials. In addition to that, the research carried out using lossy resonators has also been helpful in understanding the behavior of resonators in a filter network with the change in amount of loss. The thesis provides a detailed discussion on methods developed to determine the dielectric properties of materials using the reflected group delay of lossy resonators. Methods of dielectric characterization proposed in the thesis can be categorized as methods using an overcoupled coaxial resonator for testing the materials filled inside it and methods using a capacitively coupled microstrip circuit for testing the microstrip substrates. Mathematical models for these methods are based on the reflected group delay of an overcoupled lossy resonator and can be applied in a procedural manner to extract the dielectric constant and loss tangent of the material under test. The errors in extracting dielectric constant and loss tangent are 2%-5% and 30%-100% respectively and depend on the resonator type, material under test, and test setup parameters. The methods are validated through the characterization of various materials using both the coaxial and microstrip resonators. A method of lossy filter design using reflected group delay is also proposed in this thesis. The research presented in this part of thesis describes the effect of decrease in Q-factor on the in-band response in terms of insertion loss and return loss. It also explains the effect of loss on the group delay of a filter network and introduces the use of negative group delay in lossy filter design. The proposed method tends to recover the loss of in-band flatness due to decrease in Q-factor through resistive cross coupling. A circuit model for microstrip coupled line bandpass filter with different specifications are derived using the proposed method to study the improvement in the in-band flatness. The method of group delay is then integrated with Implicit Space Mapping (ISM) technique to derive EM models for the corresponding circuit models. The quantitative analysis of the simulated scenarios using the proposed method shows a significant improvement of 0.5-2.0 dB in the in-band flatness of the filter response. Finally, a microstrip filter is fabricated and tested to validate the method proposed for lossy filter design.
Open Access
Effect of Salinity on Evaporation from Water Surface in Bench-Scale Testing
(Multidisciplinary Digital Publishing Institute, 2021-07-29) Suchan, Jared; Azam, Shahid
Freshwater and hypersaline lakes in arid and semi-arid environments are crucial from agri- cultural, industrial, and ecological perspectives. The purpose of this paper was to investigate the effect of salinity on evaporation from water surfaces. The main achievement of this research is the successful capture of simulated climate–surface interactions prevalent in the Canadian Prairies using a custom-built bench-scale atmospheric simulator. Test results indicated that the evaporative flux has a large variation during spring (water/brine: 1452/764 10−4 g·s−1·m−2 and 613/230 × 10−4 g·s−1·m−2 night) and summer (1856/1187 × 10−4 g·s−1·m−2 day and 1059/394 × 10−4g·s−1·m−2 night), and small variation in the fall (1591/915 × 10−4 g·s−1·m−2 and 1790/1048 × 10−4 g·s−1·m−2 night). The primary theoretical contribution of this research is that the evaporation rate from distilled water is twice that of saturated brine. The measured data for water correlated well with mathematical estimates; data scatter was evenly distributed and within one standard deviation of the equality line, whereas the brine data mostly plotted above the equality line. The newly developed 2:1 water–brine correlation for evaporation was found to follow the combination equations with the Monteith model best matching the measurements.
Open Access
Engineering Properties of Badlands in Semi-Arid Regions
(Faculty of Graduate Studies and Research, University of Regina, 2012-11-28) Khan, Fawad Muhammad; Azam, Shahid; Ng, Tsun Wai Kelvin; Coulson, Ian M.; Panesar, Harpreet S.
Geology and seasonal weather variations govern the engineering properties of Avonlea badlands in Saskatchewan, Canada. Three surface sediments exhibiting distinct lithologic variations were found: a steep and fissured sandstone; a mildly-sloped and popcorntextured mudrock; and a flat and eroded pediment. The variation in material composition and the water availability conditions increase the saturation-desaturation cycle that ultimately affect material behavior. The fines content increased from dry to wet state with 17% to 33% for sandstone, 4% to 98% for mudrock, and 21% to 42% for pediment. The water adsorption capacity was found to be highest for mudrock (wl = 96% and wp = 47%) followed by sandstone (wl = 39% and wp = 31%) and then by pediment (wl = 31% and wp= 23%). The SWCC of sandstone and mudrock showed bimodal distributions with a low AEV (6 kPa and 9 kPa) pertaining to drainage through cracks and a high AEV (160 kPa and 92 kPa) associated with flow through the soil matrix. The pediment followed a unimodal SWCC with a single matrix AEV of 4 kPa. The saturated hydraulic conductivity for sandstone, mudrock and pediment measured 8.5 x 10-6 m/sec, 4.0 x 10-8 m/sec, and 1.8 x 10-5 m/sec respectively. XRD analyses indicated that the major clay minerals present were 14% illite (micaceous clay) in sandstone, 2.3% smectite, 7% kaolinite and 3.1% illite in mudrock while 3.8% illite in pediment. Mudrock was identified as the severe swelling potential badland sediment if desiccated. Overall, the swelling potential observed for sandstone, mudrock and pediment was approximately 19%, 102%, and 2% respectively.
Open Access
Factorial Probabilistic Methodologies for Water Resources and Hydrologic Systems Analysis Under Interactive Uncertainties
(Faculty of Graduate Studies and Research, University of Regina, 2015-04) Wang, Shuo; Huang, Guo (Gordon); Azam, Shahid; Young, Stephanie; Henni, Amr; Yao, Jingtao; Valeo, Caterina
Water resources issues have become increasingly prominent worldwide. Optimization and simulation techniques are recognized as powerful tools to deal with water resources issues in an effective and efficient way. Nevertheless, various uncertainties and complexities exist in water resources and hydrologic systems, posing significant challenges to water resources planning and hydrologic predictions. Advanced optimization and simulation methodologies are thus desired to address the challenges involved in solving complex water resources problems. In this dissertation research, a set of factorial probabilistic methods have been developed, which mainly deal with two types of problems: one is the inexact optimization for water resources planning and management, and the other is the uncertainty quantification for hydrologic simulations. The proposed methodologies include: (a) an inexact two-stage mixed-integer programming model with random coefficients (ITMP-RC); (b) an inexact probabilistic-possibilistic programming model with fuzzy random coefficients (IPP-FRC); (c) a risk-based factorial probabilistic inference (RFPI) method; (d) a multi-level Taguchi-factorial two-stage stochastic programming (MTTSP) method; (e) a risk-based mixed-level factorial-stochastic programming (RMFP) method; (f) a multi-level factorial-vertex fuzzy-stochastic programming (MFFP) method; (g) a factorial probabilistic collocation (FPC) method; and (h) a factorial possibilistic-probabilistic inference (FPI) method. ITMP-RC and IPP-FRC methods improve upon existing inexact optimization methods by addressing randomness and fuzziness in the coefficients of the objective function. RFPI, MTTSP, RMFP, and MFFP methods that combine the strengths of optimization techniques and statistical experimental designs are capable of exploring parametric interactions as well as revealing their effects on system performance, facilitating informed decision making. FPC and FPI are factorial probabilistic simulation methods, which have been applied to the Xiangxi River watershed in China to enhance our understanding of hydrologic processes. FPC improves upon the well-known polynomial chaos expansion technique by facilitating the propagation of parameter uncertainties in a reduced dimensional space, which is useful for representing high-dimensional and complex stochastic systems. FPI is able to simultaneously take into account probabilistic inference and human reasoning in the model calibration process, achieving realistic simulations of catchment behaviors. The proposed methods are useful for optimization of water resources systems and for simulation of hydrologic systems under interactive uncertainties.