Natural Resources Engineering - Master's Theses

Permanent URI for this collectionhttps://laurentian.scholaris.ca/handle/10219/2102

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The impact of temperature and pH on lipid production of seasonally bioprospected microalgae
(2024-04-29) McGrath, Samantha Jade
Microalgae produce economically valuable metabolites that can be used in the renewable energy and biopharmaceutical industries. In particular, microalgae have been identified as promising lipid producers, where total quantities and profiles can be enhanced by subjecting microalgal cells to stress conditions such as temperature and pH. However, while cultivation conditions can influence the feasibility of mass production of microalgae, harvesting them from their growth medium remains a significant economic hurdle. Therefore, this thesis initially presents a literature review of available harvesting methods and their associated costs. The review is followed by a study on bioprospected microalgae from various industrially impacted aquatic environments. The thesis also examines factors impacting lipid production on microalgae bioprospected over a year and investigates the effect of exposure to variations in temperature and pH culture conditions. The impacts on growth rate, total lipid accumulation and lipid profiles were determined. It was found that changes in temperature affected microalgal biomass and lipid production more than changes in pH. However, the samples' lipid profiles varied significantly as a function of both temperature and pH. Therefore, the economical production of biofuels using microalgae requires a careful selection of strains to match growth conditions to enhance productivity.
Genetic algorithm framework for stochastic open pit mining optimization problems
(2022-09-22) Amponsah, Shadrach Yaw
Genetic algorithm (GA) is a metaheuristic evolution algorithm that has been applied in the area of combinatorial optimization problems. One of these areas of optimization is mine production scheduling. Mine production scheduling is the process of determining the sequence of block extractions over a period of time that will yield the maximum net present value (NPV) for the mining operation subject to a set of constraints. The block extraction sequence needs to occur under certain resource constraints, which presents an NP-hard problem. NP-hard problems are computationally intractable and complex to solve for large- scale problems using exact mathematical models such as Mixed Integer Linear Programming (MILP) and Stochastic Mixed Integer Linear Programming (SMILP). In the mining production scheduling problem, the conventional approach is to use a single interpolated orebody model as the basis for production scheduling. This approach, however, does not consider grade uncertainties. These uncertainties have a significant impact on the NPV and can only be accounted for when modelled as part of the optimization problem. However, modeling these as part of the optimization problem increases the complexities associated with the production scheduling. In this research, a metaheuristic optimization framework based on GA was designed and implemented to solve the NP-hard large-scale open pit production scheduling (OPPS) problem. The problem definition and the resource constraints were formulated and optimized using a specially designed mining-specific GA. A multiple chromosome encoding technique was used in the GA to handle partial block processing to obtain a near-optimal solution. Two case studies from an oil sands dataset were presented in this research. A stochastic formulation (SGA) of the OPPS problem to incorporate grade uncertainty based on equally probable orebody realizations was considered and optimized with the GA framework. A deterministic approach (DGA) to the OPPS problem that did not consider grade variability was also presented. The NPV and computational time from the DGA scenario were compared to a MILP model solved with CPLEX and the SGA scenario was compared to a SMILP model solved with CPLEX as a means to validate and analyze the GA results. There was a 53.6% improvement in the computational time for the DGA compared to the MILP model with CPLEX in Case Study 1. However, the NPV was within 5.1% of the MILP model with CPLEX. The SGA model for Case Study 1 generated an NPV within 5.3% of the NPV of the SMILP model with CPLEX. Conversely, the result of the SGA model was generated in a computational time that was 75.2% better than the SMILP model with CPLEX. For Case Study 2, whereas the MILP model generated NPV of $10,175 M at a gap of 10% after 226 hours, the DGA model generated NPV of $9,142 M at 12.9% gap after 1.3 hours. Additionally, while the SMILP model was at a gap of 101% after 28 days, the SGA model generated NPV of $10,045 M at 10.6% gap after 1.5 hours.
Energy consumption and GHG emissions at metal mines in Canada and the implications of Canadian climate change polices
(2023-03-08) Smith, Connie
The objectives of this research are to complete a review of energy consumption and greenhouse gas (GHG) emissions at metal mines in Canada, to understand the implication of Canadian climate change legislation for operations at these mines, and to assess practical actions mines can take to reduce their GHG emissions. The mining industry is an energy intensive but profitable industry that plays a critical role in the Canadian economy and the switch to a “green” economy. However, the reliance of the mining industry upon carbon rich fuels, the large and long term land use changes associated with mines sites, and the long life span of mining operations mean that the industry is an important contributor to climate change.
Evolution of seismic response and seismic hazard at Goldex Mine’s D1-zone
(2022-10-24) Stratton, Ray
This thesis observes both the evolution of the seismic response and associated seismic hazard at Goldex Mine’s D1-zone over the time period including August 2018 until December 2020. A variety of evaluation methods have been used to discuss the changes in seismic response, the source mechanisms, and the associated hazards. Data visualization and analysis were performed using mXrap software (Australian Centre for Geomechanics). Ultimately, the hazards of the change in seismic response are associated with significant or large seismic events occurring at times well outside of the normal blasting times. Understanding the role that both mining sequence and production constraints plays in the seismic response is key to understanding relative hazards. The change over time as the extraction ratio of the orebody increases is also considered.
Modelling of an industrial Nickel powder decomposer
(2021-09-21) Raufu, Jelil
The nickel carbonyl, primarily known as Nickel tetracarbonyl gas, is decomposed when it is subjected to high temperature at an elevated pressure to produce nickel powder and carbon monoxide. The nickel powder thermal decomposer process has been used in the industry for nickel purification for over a hundred years. However, theoretical dynamic modelling on this process is limited and the few ones are primarily based on empirical models. In this work, a theoretical and empirical dynamic modelling of nickel carbonyl thermal decomposer is presented. Theoretical modelling was carried out on the nickel thermal decomposer process based on mass and energy conservations, and both steady state and dynamic models were developed for the process. A steady-state model was proposed to describe the relationship between gas temperature and nickel carbonyl (Ni(CO)4) decomposition percentage along the reactor. A partial differential equation (PDE) model was developed to describe the dynamic profiles of the process variables. Simulations were performed to explore the dynamic effects of process variables. The results indicate that feed flowrate affects the gas temperature and the dynamics of temperature gets slower from sections(1-4). The simulated results also show that one zone wall temperature mainly affects the internal temperature at the same zone with the impact also seen spread across to other sections. The obtained theoretical models help to enhance our understanding of the process, provide the needed information for process design, optimization and improved process control. The model also gave background information about the important variables for empirical modelling. Based on the industrial test data, empirical models were proposed for the nickel thermal decomposer process for the purposes of enhancing process control . The sections(1-4) internal temperature profiles of the decomposer were modelled as a function of 4 wall temperature input and input feed flowrate into the decomposer process. The obtained empirical models describe the dynamics of the internal temperature profile. The models show that the feed flowrate has effect on the internal temperature of the Nickel powder thermal decomposer and its effect increases as the gas mixture flows through from section 1 to section 4 of the decomposer. The input feed gas flowrate has negative gains on the internal temperatures of 4 sections. The wall temperature input has positive gains on the internal temperature of the same section but its impact spreads across other sections. The obtained empirical models were evaluated by comparing the model predicted data with industrial measured data and model residuals were also calculated. The results indicate that the obtained models match the industrial data reasonably well. The obtained models provide a necessary basis for applying advanced process control and thereby improving process quality and production efficiency
The distance analysis of a mine scale event
(2022-02-25) Ollila, Benjamin
Mining induced seismic events greater then Nuttli Magnitude 3.0 are difficult to understand, have high potential consequences and are becoming increasingly common in Canada. The term mine scale event (MSE) is used to describe a seismic event in which the mechanisms and processes involved take place on a scale similar to that of the mine. A MSE from Nickel Rim South Mine was investigated using seismic data to explain its time, location and large magnitude. A novel tool, Time Distance Analysis was developed to identify spatial-temporal trends in seismicity around the MSE. Guidelines were developed to account for the unknown spatial and temporal extent of the processes that led to and were affected by the MSE. The results showed that preceding seismicity tended to coalesce around the eventual hypocenter of the MSE while subsequent seismicity migrated away. The coalescence was interpreted to represent the deterioration of a fault asperity, leading to an eventual rupture. After the MSE occurred, the dispersion of seismicity was interpreted to represent an unloading of the source region.
Incorporating grade uncertainty in oil sands mine planning and waste management using stochastic programming
(2020-02-12) Mbadozie, Obinna
The primary purpose of oil sands mine planning and waste management is to provide ore from the mine pit to the processing plant while containing the tailings in an efficient manner in-pit. Incorporating waste management in the mine plan is essential in maximizing the economic potential of the mineral resource and minimizing waste management costs. However, spatial variability such as grade uncertainty results in ore tonnage variations, which leads to fluctuations in the quantity of ore to be processed and waste to be managed. If grade uncertainty is not incorporated in oil sands mine planning, it may lead to under- or over-design of the waste management system required to support the mining operation, resulting in lost opportunities. Grade uncertainties have profound impact on the Net Present Value (NPV) of the mining project as it may induce large differences between the actual and expected production targets. Thus, the primary research objectives are to develop, implement and verify an integrated oil sands mine planning optimization framework using Stochastic Mixed Integer Linear Programming (SMILP) to integrate the related domains of bitumen grade uncertainty and waste management. The SMILP model determines the order and time of extraction of ore, dyke material and waste that maximizes the Net Present Value (NPV), minimizes waste management cost, and minimizes the geological risk cost of the mining operation. Sequential Gaussian Simulation (SGS) is employed to quantitatively model the spatial variability of bitumen grade in the oil sands deposit. Multiple simulated orebody models are used as inputs for the SMILP model to generate optimal mine plans in the presence of grade uncertainty. MATLAB programming platform was chosen for the SMILP framework implementation. A large-scale optimization solver, IBM CPLEX, is used for this research. To validate the SMILP model, an oil sands case study was implemented based on SGS realizations block models to generate a stochastic integrated production schedule (SMILP schedule), and the results compared with a conventional production scheduling approach based on Ordinary Kriging block model (OK schedule) and E-type block model (E-type schedule). The E-type block model is the average block model of the SGS realizations. In comparison, the SMILP schedule which was based on the developed SMILP framework generated an uncertainty-based integrated production schedule and waste management plan with better financial profitability compared to the OK and E-type schedules. Additional numerical experiments and analysis was done by applying the three schedule results to each of three randomly selected realizations. The corresponding SMILP schedules generated from the realizations were consistently uniform and smooth compared to similar OK and E-type realization schedules. The SMILP framework accounts for geological risk by placing higher penalties for ore grade and ore tonnage deviations from production targets in the early years of mine life to defer production deviations to later years when more geological information becomes available to update the block model and mine plan. By deferring geological risk to later years, the risk of not reaching production targets in the earlier years is minimized, thus creating a smoother and stable production schedule. The results demonstrate that the SMILP schedule generates 14% and 17% improvements in NPV compared to the E-type and OK schedules respectively. These results prove that the SMILP model is a useful tool for optimizing stochastic integrated oil sands production schedules whilst taking into account grade uncertainty.
Electrolytic destruction of cyanide on bare and MNO2 coated 304 stainless steel electrodes
(2021-09-15) Schmidt, Jacob
MnO2 coated lead and ANSI-304 stainless steel anodes were evaluated for use in electrolytic cyanide waste effluent treatment. Cyclic voltametry experiments revealed that MnO2 on lead was too resistive to be a feasible substrate. Cyclic voltammetry on bare and MnO2 coated steel shows evidence of cyanide destruction just prior to the onset of massive oxygen evolution, suggesting a reaction mechanism in which cyanide is oxidized via reaction with hydroxide radical species on the electrode surface. Galvanostatic experiments showed little difference in cyanide oxidation performance behaviour between bare steel and the MnO2 coating. However, copper ion were found to catalyse cyanide oxidation for bare steel, but had no observed effect for MnO2 coated steel. A cost analysis was done comparing electrolytic cyanide destruction using bare steel anodes to the INCO SO2/Air process. Electrolytic cyanide oxidation was concluded to have significantly lower operating costs, but is infeasible due to prohibitive capital costs.
An investigation into the feasibility of improving the sustainability of a biogas fueled electricity generator by capturing CO2 exhaust emissions using photosynthetic green microalgae
(2020-10-28) Kennedy, Merritt
Municipal solid waste landfills release a methane rich biogas, which can be combusted in standalone electricity generators. This work, which measured the exhausted off-gas from a biogas fed generator, which at an average of 526˚C was 5,556 Nm3 /hour and contained 11% CO2. It is hypothesized that this off-gas could be captured and used as a year-round carbon source for photosynthetic microalgae. A pilot plant concept is modeled to be built at later date for a feasibility CO2 capture study. The proposed pilot plant consists of ten 1 m3 tanks (1 seed tank, 3 sets of biological triplicates) and would take 0.34% of the total off-gas. The model produced indicated that it could be operated above 15˚C and 30˚C year-round and has the potential to produce 2.7 kg dry weight microalgae m-3 day-1 of lipid-rich microalgae for research and market analysis purposes.
Monte Carlo simulations and experiments of Bessel beams and tissue-like phantoms interaction
(2017-02-23) Yang, Jianing
In this thesis, the propagation of Bessel beam in tissue and its potential advantages were explored numerically and experimentally. In the numerical simulations, the Monte Carlo method is used to simulate the propagation of Gaussian and Bessel beams in tissue. By convolving the impulse profile generated by a pencil beam’s propagation with either beam intensity profile, the response of the propagation of the said beam can be approximated. This process was done by modifying and using MCML and CONV software which are available from the literature. Experimentally, the Bessel beams were generated by a laser and axicons, and made to propagate through optical phantoms formed with variable density intralipid solutions. The intensity distribution of the transmitted Bessel beam at the exit of the scattering media was measured and compared with transmittance results from simulation. At last, a separate experiment was designed to investigate the reconstruction of a Bessel beam after it passes the optical phantom.
The role of cancellous bone architecture in misalignment and side effect errors
(2019-12-11) Bennison, Matthew B. L.
Cancellous bone is often found at the ends of long bones and similar load-bearing surfaces. Its complex architecture allows high stiffness and strength, while also minimizing the mass and metabolic needs of the bone. This architecture confounds attempts to measure cancellous bone’s mechanical properties to produce a model for predicting its response to various loading scenarios (e.g., falls). Two of these experimental challenges, specimen misalignment and “side effects”, are known to be significant; however, the role of architecture on the magnitude of these artefacts is unknown. The current study used finite element method (FEM) modelling of bovine cancellous bone to examine this issue in more detail. Misalignment is strongly dependent on bone volume fraction (BV/TV) and degree of anisotropy (DA). Side-effects are affected by trabecular spacing (Tb.Sp), as well as BV/TV and DA. These findings will result in more accurate testing, and hence more accurate modeling, of cancellous bone behaviour.
Lattice boltzmann models for heat transfer and anisotropic flows
(2019-10-16) Wang, Zimeng
Fluid flows and associated heat and mass transfer problems are governed by several nonlinear second-order partial differential equations for which the analytical solutions are hard to obtain. Therefore, the numerical simulations are very useful in the research of the flow and heat transfer problems. In the last decade of the 20th century, a relatively new computational fluid dynamic (CFD) method, so called the lattice Boltzmann method (LBM) was proposed. The method is coding and meshing friendly and is rapidly developing in recent years. In this thesis, three new methods for the flow and heat transfer based on the LBM are presented. First, we give a counter-extrapolation approach to calculate the heat and mass transfer problems between conjugate interfaces with the interfacial discontinuity. By applying the finite difference approximation and extrapolation, the conjugate interface problem can be separated into two individual heat and mass transfer problems with Dirichlet boundaries, and the Dirichlet boundary problems can be solved by applying the LBM (or other CFD methods). Secondly, we consider the inlet and outlet treatment of periodic thermal flow. The periodic features of fully developed periodic incompressible thermal flows will be carefully examined by applying the LBM. The distribution modification (DM) approach and the source term (ST) approach are proposed, which can be both used for periodic thermal flows with constant wall temperature (CWT) and surface heat flux boundary conditions. The last method is a rectangular lattice Boltzmann model for anisotropic flows based on coordinate and velocity transformation. Unlike the other existing rectangular models which tuned the lattice Boltzmann algorithm to fit the rectangular or cuboid lattice grids, this method applies the general lattice Boltzmann method to solve the transformed system over regular square lattice grids. All these methods have been carefully examined in several simulations by comparing the LBM results to those of analytical solutions and previous publications using different numerical techniques. The results of the first and second methods are satisfactory. However, the result of the last method for the rectangular lattice Boltzmann model suffers numerical instability and inaccuracy. The reason has been analyzed, and a possible reform has also been suggested. The future research topics for each method have been proposed as well.
Temperature modeling and control of the sulfuric acid plant in an industrial smelter
(2019-06-25) Caron, Sarah
Roasting, smelting and converting are pyrometallurgical techniques used to eliminate gangue rock from sulfide ores and produce a saleable metal product. Due to the large amount of sulfur present in sulfide ores, the off-gas produced from pyrometallurgical processing is laden with sulfur dioxide (SO2). Production of sulfuric acid (H2SO4), from off-gas laden with SO2 is one of the methods used at smelters to reduce the amount of SO2 being released into the atmosphere. The acid plant consists mainly of a catalytic converter, absorption towers and a network of heat exchangers. SO2 is converted to sulfur trioxide (SO3) which is absorbed to produce a sulfuric acid product. Efficient oxidation of SO2 occurs within a tight temperature range so heat exchangers equipped with bypass valves are used to regulate the temperature throughout the acid plant. In this dissertation, a steady-state model is developed from fundamental steady-state mass and energy balances. The steady-state model provides a relation between the process variables and the temperature of the outlet streams of the heat exchangers. Unknown variables are estimated using industrial operating data. The steady-state model is used to investigate the effect of process variables on the controlled variables. The disturbance variables that have the largest effect on the process are the feed gas flow rate and the SO2 concentration. The results provide useful information since with recent process modifications that are part of the Clean AER project, variations in the feed gas flow rate and SO2 concentration will increase. The effects of the manipulated variables were also investigated which provides a foundation of understanding for process control. The results of the investigation of the effect of process variables on the controlled variables were quantified by calculating the steady-state gains. The dynamics of the process were investigated through analyzing the industrial operating data. The output variables do not vary simultaneously with changes in the input variables. The correlation coefficients were determined for the variables. The correlation coefficient between variables provides an estimate of how much influence the input variables have on the output variables. Delayed correlation analysis was performed to explore the process dynamics. Dynamic models were identified using industrial operating data with and without prior information supplied using the System Identification toolbox in Matlab. Providing the steadystate gains and an estimate of the process time constants to the System Identification toolbox greatly improved the identified model. The dynamic model was validated by comparing the model-estimated output and the output from industrial operating data. Temperature control within the acid plant is a multiple-input-multiple-output control problem. Bristol’s Relative Gain Array and Singular Value Analysis are used to determine the most effective pairing of variables. A feedforward-feedback control scheme for temperature regulation is explored. Simulations for major disturbances, such as flow rate and SO2 concentration of the feed gas, are carried out using two alternative controller pairings. The results of the simulations are reviewed and the advantages of each controller pairing are discussed.
Semi-automation of a rockbreaker system: dynamic modeling and optimal collision-free trajectory planning
(2018-06-28) Tremblay, Louis-Francis
In light of technological advancements, the mining industry is seeing an increase in equipment automation. A hydraulic rockbreaker is a machine that would bene t from automation. The goal of this research is to develop some of the necessary algorithms to render a rockbreaker semi-autonomous. Semi-automation of such systems would allow for improved ease of use, increased productivity and e ciency of rock breaking operations, reduced maintenance costs while also removing the operator from harm's way. Several components are necessary to make semi-automation feasible, including a dynamic model as well as trajectory planning algorithms which generate collision-free trajectories to be used by a controller. The development of a complete dynamic model for such a system would allow for better control when using model-based controllers. However, such a model is di cult to develop in practice, has added complexity and may be computationally expensive. In this work, simpli ed dynamic models are developed and compared with respect to a complete dynamic model of the rockbreaker. One of the resulting simpli ed dynamic models, which only considers the inertial and gravitational e ects of the rockbreaker's mechanical links as well as the gravitational e ects of its hydraulic actuators, is shown to provide adequate representation of the system so as to be used in a model-based controller. The work also develops a set of o ine trajectory planning algorithms that generate time-optimal trajectories which ensure smooth motions and hydraulic valve actuation while satisfying the system's ow rate constraints. With the addition of a collision avoidance strategy and collision detection algorithm, the generated trajectories within the system's work environment can be expected to be collision-free.
Interpretation of rock mass yield using apparent stress of microseismic events – examples from Glencore’s Nickel Rim South Mine, Sudbury, Ontario
(2018-05-11) Carusone, Oliver Thomas Sousa
Seismic events are manifestations of sudden, inelastic deformations in a rock mass. The characteristics of these deformations are reflected in quantitative descriptors of seismic events, known as seismic source parameters. The seismic source parameter apparent stress (σa) is a relative estimate of co-seismic stress change. This parameter has been used by other authors to infer local stress conditions in a rock mass and how they vary in space and time. This thesis investigates short term space-time variations in apparent stress in spatially-isolated volumes of a rock mass following open stope blasts. The results are used to infer how the new excavation affects the nearby rock mass. These excavations are expected to cause local stress increases as stress redistributes around the void, and stress decreases as rock mass near the excavation yields and sheds stress. Data for this research is taken from Glencore’s Nickel Rim South Mine (NRSM) in Sudbury, Ontario. This modern operation has a state-of-the-art microseismic monitoring array that consistently locates events with less than 5 m of residual error and provides accurate source parameter estimates for large and small events. NRSM uses a bulk open stoping mining method, which creates large excavations on the order of several thousand tonnes in a matter of a few seconds. The large stress changes and loss of confinement produced by these blasts can generate large seismic responses which provide an abundance of information about rock mass behaviour. Analysis of apparent stress over time is performed spatially isolating a group of events and tracking apparent stress variation in a moving window. This analysis shows that apparent stress: • Rapidly increases for a matter of minutes immediately following the blast. • Gradually decreases for a matter of hours to a lower level than before the blast. • Slowly increases over a matter of days to weeks. Based on the mechanics of rock masses near excavations and use of apparent stress to infer local stress conditions, these variations are interpreted to correspond with: • Mining-induced stress increasing with the creation of a new excavation. • Stress decreasing as the rock mass near the stope yields and/or enters its post-peak strength. • Stress increasing farther from the stope as a result of the more damaged rock mass closer to the stope shedding stress onto less damaged regions. Variations in event-stope distances are also analysed to re-enforce the inferences made based on the variations in apparent stress over time. The analysis of event-stope distances shows that events: • With high apparent stress tend to locate farther from the stopes than events with low apparent stress. • Initially move away from the stopes for a matter of hours after the blast. • Gradually move back towards the stopes for a matter of hours to days. • Gradually move away from the stopes again for a matter of days to weeks. The inferred rock mass behaviour based on these variations are: • Higher stress conditions in more confined and less damaged regions of the rock mass. • Stress redistributing around the new excavation and creating a new zone of active rock mass yield. • Yield occurring in a more consistent region of the rock mass as redistribution of stress outside the more damaged regions slows. • Growth of damaged zones as rock mass yield progresses over time These observed variations and inferred behaviour are used to propose a conceptual model for rock mass yield which describes the formation of an excavation damage zone following a blast. Further study based on this research may use more detailed aspects of the variations to calibrate constitutive behaviour of rock masses (making it a useful tool for numerical model calibration), or relate variations in apparent stress to the occurrence of large events (making it a useful tool for seismic hazard forecasting).
Computer-based application to assess gross motor skills using Microsoft Kinect sensor
(2018-03-07) Bragança Moraes, Arina
The performance of a fundamental motor skill in early childhood can be investigated using diverse assessment tools. Although the classical tests are reliable and useful for motor skills assessment, they have some limitations. The launch of the Microsoft Kinect marked a revolutionary advancement for developers thanks to the depth camera and its affordable price. This work aims to develop a reliable computer-based application using the Microsoft Kinect sensor to implement the third version of the Test of Gross Motor Development (TGMD-3). The assessment consists of customized algorithms that verify if the 3D position of the most relevant joints for each subtest varies along time according to the respective performance criteria. The proposed system returns an immediate feedback to the participant, indicating if s/he passes or fails the selected subtest. The results revealed the computer-based application for assessing gross motor skills is accurate, although it is limited by the space requirements.
Evaluation of the thermal impact from battery packs from electrical vehicles in underground mining environment
(2019-01-10) de Almeida, Daniel Marques
One of the main aspects which governs the size of ventilation facilities in underground mines is the amount of heat load generated in the underground environment. This heat load comes from many different sources, one of which is the heat contributed by underground diesel machinery operation. One strategy to mitigate the heat and other emissions from such equipment is to substitute these units to similar performance, but more thermally efficient, electric machinery. This study presents a heat load evaluation of the Lithium-iron Phosphate battery system used in a prototype electric mining vehicle. The set of equations which governs the heat generation from these devices have been developed by previous researchers and is used in this thesis to calculate the heat generation and loss. However, in the mining industry, the current methodology for heat load calculation from electric vehicles (EVs) is usually based on the rated power or on a simple power loss equation. This strategy might lead to incorrect estimations of the heat load from this type of machinery. Experimental and simulation work has been conducted as a means to evaluate the heat flux from the Lithium-iron Phosphate battery system. The battery was tested through charging and discharging it under different levels of current within the 10% to 90% range of its maximum capacity. The test was performed firstly with a single cell and then with a module. Furthermore, the battery system was set in operation under different environment temperature settings. These current and temperature levels represent the range of possible conditions in which the prototype will face in service. Through the estimation of the heat released from the other main electrical components in the vehicle, it was possible to calculate the heat impact of these units in the surrounding environment.
Utilizing the mechanical redundancy of parallel systems for condition monitoring hydraulic pumps in variable operation
(2018-10-02) Rose, Alexander M.
This work investigates and develops an approach to resolve some of the unique challenges associated with condition monitoring variable duty equipment. The proposed solution utilizes the mechanical redundancy of parallel systems to create dynamic criterion for detecting incipient faults. In this context, parallel systems are those which contain multiple subsystems (with similar construction) having synchronized operating conditions. This work evaluates the proposed methodology through its application on parallel hydraulic gear pumps. By comparing the dynamic pressure and vibration signal features, it was found that this approach is capable of distinguishing various incipient failures while the pumps were in both stationary and non-stationary operation.
Nanocomposites of carbon nanosphere and graphene oxide with iron oxide as high-performance adsorbents for arsenic removal
(2016-11-17) Su, Hui
Arsenic is a widely distributed element in the Earth’s crust with an average terrestrial concentration of about 5 g ton-1 . Arsenic is a persistent, bio-accumulative, toxic element. The United States Environmental Protection Agency (EPA) has implemented the discharge criterion of 10 µg L -1 for arsenic as the maximum acceptable level for ground water. During the past decades, several techniques have been developed for the removal of arsenic from the wastewater, including chemical precipitation, adsorption and ion exchange, membrane and biological removal processes, and so on. Because of the good arsenic removal efficiency and the low cost, adsorption is a more popular method. In this thesis research, two ranges of iron oxide nanocomposite adsorbents have been developed and studied for their performance properties towards arsenic removal. Novel iron oxide encapsulated carbon nanospheres (FeOx-CNS) with excellent arsenic adsorption performance has been successfully synthesized. CO2 activated carbon nanospheres material (A-CNS) with high surface area (2271 m²g -1 ) and high pore volume (5.18 cm³g -1 ) was selected as the porous matrix. After surface oxidation by ammonium persulfate (APS), iron oxide was loaded into the carbon nanospheres as the effective arsenic adsorbent. Transmission electron microscopy (TEM) and Braunauer–Emmett– Teller (BET) results indicate that iron oxide nanoparticles (7-60 wt%) are well-dispersed within the mesopores. In particular, FeOx-CNS-13 composite shows most optimum performance properties, with high arsenic adsorption capacities achieved for both As(III) (416 mg g−1 ) and As(V) (201 mg g−1 ). Another range of amorphous iron oxide-graphene oxide (FeOx-GO) nanocomposites having different graphene oxide (GO) content (36-80 wt%) was prepared by coprecipitation of ferrous sulfate heptahydrate and ferric sulfate hydrate on GO sheets. The composites have been thoroughly characterized and investigated for their performance towards arsenic removal. The optimum composite, FeOx-GO-80 having the highest iron oxide content of 80 wt% shows excellent arsenic adsorption capacities for both As(III) (147 mg g−1 ) and As(V) (113 mg g−1 ), which are highest among iron oxideGO composites reported to date for arsenic removal. The high performance along with low cost and convenience in synthesis makes this range of amorphous iron oxide-GO nanocomposites promising for applications.
Numerical investigation of anisotropic and time-dependent behaviours of foliated rock mass
(2018-09-07) Yadav, Pranay
Squeezing ground conditions have become a major challenge faced by underground hard rock mines exploiting reserves at greater depth and in a high-stress environment. This thesis investigates the influence of various parameters on the severity of squeezing ground conditions in foliated rock mass utilizing continuum numerical modelling in FLAC3D finite difference code. A series of numerical simulations were carried out for selected cases of two mines subject to squeezing ground conditions to investigate the rock mass failure mechanisms, the influence of various geological, mining and stress parameters, time dependence and the role of rock reinforcements. The numerical models were calibrated using field data and underground observations. The numerical models were successful in capturing the observed failure mechanisms at the two mines. The calibrated numerical models were used to investigate the influence of varying interception angle, excavation shape, excavation over-break, mining depth and parallel excavations on the severity of squeezing ground conditions utilizing ubiquitous joint model. The time dependence in the numerical models was simulated by using the power ubiquitous model and the role of various rock reinforcement elements was simulated by using structural elements. The results of the numerical simulations were found to be in good agreement with the underground convergence data and observations. The modelling methodology used in the thesis can be used to improve the understanding of the anisotropic and time-dependent behaviour of the foliated rock mass to various mining conditions. The methodology can also be used to evaluate performance of various rock reinforcement strategies and elements that are used in squeezing ground conditions.

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