SHAREOK Repository
Not a member yet
49261 research outputs found
Sort by
Integrated protonic ceramic electrochemical cell for sustainable energy economy using water-energy nexus framework
Get PDFReliance on fossil fuels will continue for the next decades even though there are global pushes away from it to mitigate the overarching climate challenge, most especially by its highest consumers and availability. While there is a hastening global shift away from fossil fuel, integrating its assets into this technology helps limit the risk and future losses of stranded assets and reduce the cost of investment in the new technologies. Moreover, the generation of electricity from intermittent renewable sources like solar and wind has witnessed a significant surge in recent years, leading to a pressing demand for practical energy storage systems. Electrical energy storage is anticipated to play a pivotal role in the future global energy system, facilitating load-leveling operations to support the greater integration of renewable and distributed generation. Reversible electrochemical cells (RECs) offer a promising option for addressing the fossil fuel assets integration and energy storage challenges through the interconversion between electrical and chemical energy and concurrent utilizing carbon emission. In their electrolysis mode, the RECs convert electricity into durable, storable, and portable valuable chemical fuels such as syngas and methane. Conversely, the produced chemical fuels can be used as reactants in the fuel cell mode to generate electricity on demand with minimal (hydrocarbons) or zero when H2 or NH3 is used emissions. However, a challenging goal for this type of technology remains to achieve optimal operation and high roundtrip efficiencies, which has hindered the deployment of previous electrochemical cells. This dissertation demonstrates how reversible protonic ceramic electrochemical cells (RePCECs) can be integrated with fossil fuel power plants and renewable energy sources as a potential energy storage system. In this work, integrated RePCEC systems are designed and examined using computational modeling at scales to determine appropriate system configurations and operating conditions that achieve high roundtrip efficiencies. Cell level design of the PCEC is the first approach, several cells are assembled for the stack level model that is integrated into combined cycle powerplant and solar photovoltaic for the system level model. After critical literature review, this answered the operational and integration research questions proposed to address these challenges. The designed systems perform two functions, utilizing captured CO2 and storing renewable energy through co-electrolysis of steam and CO2.
The co-electrolysis reaction involves endothermic water electrolysis and exothermic methanation reaction. To enhance high roundtrip efficiency, there is a need for thermal balance and management in the electrolysis mode. This involves operating the RePCEC stack under conditions that favor methane production to balance out heat needed by water electrolysis, it crucial for the RePCEC system operation. Methanation is enhanced by low temperatures. Leveraging on fabricated BCZYYb-electrolyte RePCEC, the cell model designed revealed that the optimum temperature for methane production is 450℃ at atmospheric pressure. Thus, to achieve optimum system performance, operating in the temperature range 450-525℃ is recommended at the given configuration, combining between the optimum temperature for methane production and temperature for the optimum stack roundtrip efficiency. Configuration with carbon capture system and purge stream is the optimum configuration from the seven conceptualized and evaluated.
The modeling outcomes include a thermodynamic examination of integrated RePCEC systems, calibration of cell and stack level models, and steady-state simulation and integration into a 600MW combined cycle power plant retrofitted with two two-stage membrane-based carbon capture system and a wastewater treatment and recovery unit. At 100% powerplant loading, the stack and system roundtrip efficiencies are 72% and 51.37% respectively. Adding a purge stream for produced hydrogen at the system downstream improves the efficiencies to 74 and 55.48% respectively. At atmospheric pressure and 525℃, the system model suggests that a stack roundtrip of 82% is achievable, and overall system efficiency increases by reducing the energy consumption by the balance of plant components for steam generation and storage. Economic analysis of the process gives levelized cost of methane as 3.46/MMBtu and $9.85/MMBtu. The lifecycle analysis shows that the global warming potential for the production of methane and hydrogen from the RePCEC system is 3.83 kg CO2 eq which is lower than 9.35 kg CO2 eq emission during steam methane reforming for hydrogen production. This answered both the environmental and economic concerns in the raised research question.
The proposed RePCEC configuration and analysis carried out in this dissertation to address the surge in renewable energy and challenges with PCEC technology hold significant potential in achieving large-scale energy storage while simultaneously reducing carbon emissions. These advancements, coupled with suitable governmental policies and incentive programs, have the potential to economically disrupt the natural gas industries by using RePCEC systems for methane production, thereby making them more favorable for eventual implementation and commercialization
Advances in understanding polymer chemical recycling reactions
No full textPlastics revolutionized the world since the beginning of their mass production in the 1950’s. Packaging, construction, and many other industries successfully substituted materials for plastics, or found in these novel materials a new business application. Plastic production – as well as demand – has continuously grown in the past decades. Consequently, the amount of waste generated has also increased. Without an effective way to give new life to plastic waste, discarded plastic has accumulated in earth and marine environments. Accumulation of such waste is detrimental to many forms of life, and a better way to address waste is necessary.
Mechanical recycling efforts began in the 1970’s, consisting of sorting, washing, grinding, melting, and reshaping waste plastic. Although a good alternative for well-sorted polymer waste, it is not applicable to materials such as multilayer films or thermoset polymers. As such, mechanical recycling currently corresponds to less than 10% of the total plastic production. On top of that, this thermal process lowers the quality of the final products in such a way that products can only be recycled a limited number of times before their properties do not meet minimum standards, which inevitably leads to waste. Therefore, it has become clear that mechanical recycling alone is not able to tackle the challenge of waste plastics.
In order to complement mechanical recycling technologies, a new approach called chemical recycling is currently being developed. This process consists in selectively cleaving polymer molecules back into their building blocks, which are called monomers, that can then be manufactured into pristine plastic. There are many advantages involving the use of chemical recycling routes, such as that they yield products with identical performance to polymers manufactured from traditional feedstocks. There is even more potential to be unraveled as chemical upcycling routes are also being investigated. As opposed to converting polymers back to monomers, this process consists in decomposing polymer molecules into products which are more valuable than monomers, such as gasoline, diesel or alkyl-aromatics. Still, there are many challenges to be overcome, such as the fact that performance additives are often present in plastics, augmenting the recycling complexity.
These depolymerization reactions may be carried out in the absence or presence of catalysts. However, it is important to highlight that most catalyst technologies available today were originally designed to convert molecules which are orders of magnitude lower in molecular weight than plastic waste feedstock. Hence, there is a need to understand how this new feedstock will interact with traditional catalysts, and to design new catalysts to optimize polymer conversion.
This work is dedicated to improving understanding of these novel chemical recycling and upcycling reactions. Here, we discuss the impact that common polymer additives may have when they are present in a polyolefin melt undergoing pyrolysis or catalytic decomposition. This is fundamental to grasp how real-world polymer products will behave when subject to these processes, since all commercial plastic products inherently contain additives. Next, we unveil how a common additive may deposit and alter the activity of different pore-sized catalysts. Additionally, we investigate the role that polymer structures may play in the decomposition of polymers over porous heterogeneous catalysts. Finally, new catalyst design approaches are discussed to improve polymer-catalyst interaction in order to increase perceived rates of reaction. Insights from this work may help inform the industry and be one more step towards the development of optimized chemical recycling processes, which will allow for a more circular plastics economy
Scale-dependent Inflation for Multiscale Ensemble based Data Assimilation
Get PDFThe degree of the background ensemble deficiency, often manifested as ensemble underdispersion, can vary at different scales in the ensemble-based data assimilation. This study develops the new scale-dependent inflation (SDI) methods based on two scale-unaware inflation approaches, RTPS (Relaxation To Prior Spread) and SE (observation-dependent Sampling Error inflation). In the new scale-dependent RTPS inflation (RTPS-SDI), the posterior ensemble spread is relaxed toward the prior ensemble spread at each scale separately. In the Scale-dependent SE inflation (SE-SDI), mathematical derivation is performed so that posterior ensemble variance is individually adjusted toward the mean square error of ensemble analysis mean at each scale. The impact of RTPS-SDI and SE-SDI are examined and evaluated by implementing both approaches within the Multiscale Local Gain Form Ensemble Transform Kalman Filter (MLGETKF).
Four continuously cycled MLGETKF experiments are performed with the four inflation methods using a two-layer surface quasi-geostrophic turbulence model. During the DA cycling, RTPS-SDI and SE-SDI outperform RTPS and SE, respectively, in the reduction of analysis errors and the enhancement of ensemble spread nearly at all scales and all cycles. In addition, the improvements in RTPS-SDI over RTPS are greater than those of SE-SDI over SE. These improvements in both SDI methods are associated with their larger inflation at all scales, especially at larger scales, compared to their scale-unaware counterparts. In the subsequent forecast, both SDI methods show statistically significantly better forecast performance than their scale-unaware inflation experiments. RTPS-SDI is more accurate than RTPS for all scales in 1-4 days lead time. SE-SDI is more accurate than SE at all scales for 3-6 days lead time during the early cycles and shows a smaller forecast error with significance for 2-3 days
Bridging Micro- and Macro- Evolution In Tropical Fishes
Get PDFIn marine environments, barriers to dispersal can be challenging to identify because they are often cryptic. Unlike terrestrial environments, where a mountain chain that is visible can physically separate two populations of animals, vast masses of water in the ocean make it challenging to pinpoint these barriers. Therefore, the impact of these barriers on the formation of new species in the ocean is still not well understood. While most marine populations have long been considered to be well connected via long-distance dispersal, molecular ecology studies are increasingly unveiling inconspicuous barriers that promote population divergence and ultimately speciation. The advent of genomic techniques that allow the generation of data for thousands of genes has provided an unprecedented opportunity to uncover marine barriers that were previously invisible using more rudimentary tools. This, in turn, has opened new avenues for understanding of how barriers to dispersal affect population connectivity in the marine environment. The overarching goal of my dissertation is to use genome-wide data to look for genetic patterns that correspond to such barriers, and to test for their effect at short-, intermediate- and long-term evolutionary scales, going through a continuum from micro- to macro-evolution, in a time span from thousands to millions of years.
At the short-scale, I examined two controversial cases of species delimitation. Species delimitation is a major question in biology and is essential for adequate management of organismal diversity. The first challenging case involves the red snappers in the Western Atlantic. Red snappers have been traditionally recognized as two separate species based on morphology: Lutjanus campechanus (northern red snapper) and L. purpureus (southern red snapper). However, recent genetic studies using few molecular markers failed to delineate these nominal species, lumping the northern and southern populations into a single species (L. campechanus). To evaluate if the populations of these fish represent one or two species, my project applied ca. 40,000 genome-wide markers of 178 individuals collected throughout the range of the two species and population and species delimitation analyses. Overall, my results supported the isolation and differentiation of these species, a result that confirmed the morphology-based delimitation scenario, highlighting the benefits of using genome-wide data in complex cases of species delimitation (Chapter I, published in Proc. Roy. Soc. B in 2019).
The second study case involves a species complex of silverside fishes (Chirostoma humboltianum group: Atherinidae) in the Central Mexico plateau. The humboltianum group represents a taxonomically-controversial species complex where previous morphological and molecular studies based on a few genes produced conflicting species delineation scenarios. I applied an integrative approach that considered multiple lines of evidence to investigate the species numbers and boundaries comprising this contentious group. I used ca. 33,000 molecular markers for 77 individuals representing the nine nominal species in the group, spanning their distribution range in the central Mexico plateau, in combination with morphologic and ecologic information. My findings are inconsistent with the morphospecies and ecological delimitation scenarios, identifying three to four species. This study provides an atypical example in which genome-wide analyses delineate fewer species than previously recognized on the basis of morphological data alone. It also highlights the influence of geologic history as a main driver of speciation in the group (Chapter II, published in BMC Eco. Evol. B in 2022).
At the intermediate- scale, I evaluated the influence of historical (e.g., geophysical events) and contemporary barriers (e.g., habitat gaps) hindering genetic flow among populations by studying the spatio-temporal phylogenetic concordance of co-distributed lineages. For this study, I investigated the comparative phylogeography of labrisomid blennies in the genus Malacoctenus. I generated data for ca. 28K genome-wide markers that were sequenced from over 500 individuals collected from 38 locations, representing 23 (out of 25) species of Malacoctenus. With this dataset, I assessed the effect of recognized historical (e.g., the rising of the Isthmus of Panama) and contemporary barriers (e.g., sandy gaps) in the Tropical Eastern Pacific (TEP) and the Tropical Atlantic (TA) biogeographic realms. These blennies represent an ideal system to test the effect of such barriers as they are strongly associated with rocky habitats and coral reefs. Therefore, subtle habitat disruptions may lead to genetic isolation. At the micro-evolutionary scale, the observed population structure patterns identified the Sinaloan and Central American breaks as the major breaks in the TEP; and the Bahamas and Eastern Caribbean breaks as key barriers disrupting connectivity in the TA. All in all, the effect of these breaks varies across species, suggesting that species-specific traits (e.g., habitat preference), also greatly influence their dispersal capabilities. My study identified five instances where marine barriers promoted the diversification of independent evolutionary lineages that could potentially represent species complexes. Some of them supported by evidence of population differentiation from previous morphological analyses as well as by my geometric morphometric analyses. Major environmental variables driving population differentiation in the TEP are depth, temperature, chlorophyll altogether with spatial components, while in the TA suspended particle matter also influences diversification.
At the long-term scale, my results suggest that depth is a primary driver of speciation in the TEP, leading to niche divergence between tide pool- and reef-associated clades. In contrast, in the TA, patterns of environmental association appeared more intricate, where depth, temperature, chlorophyll and physical features significantly contributing to speciation in this region. Finally, our time-calibrated analyses at macroevolutionary scales elucidated an Eastern Atlantic origin of the clade followed by an east-to-west dispersal. Although the historical break attributed to the rise of the Isthmus of Panama had a substantial influence on the evolutionary history of the genus, our analyses demonstrate that it did not triggered synchronous cladogenetic events. In summary, by using a combination of population genomics, comparative phylogeography, phylogenomics, seascape genomics, and geometric morphometric approaches, this study highlights major contemporary and historical barriers hindering population connectivity in the TEP and TA biogeographic regions, enhancing our understanding of the forces and processes generating new species in marine systems (Chapter III, to be submitted for publication).
All in all, my thesis highlights that the use of genome-wide data provides unprecedented resolution to unveil patterns of genetic structure, commonly unraveling cryptic diversity, and the opportunity to address species delimitation problems. By uncovering the spatio-temporal genetic patterns of fishes along the evolutionary continuum, my dissertation provides novel insights into the evolutionary and biogeographic history of marine and freshwater Neotropical fishes. Overall, my dissertation not only helps to understand the evolutionary history of the species under study, but more generally, elucidate factors driving evolutionary process in the marine realm, ranging from population-level scales, to speciation, to higher level relationships among groups
Hybrid Decision making model using linear programming and analytical hierarchical process for comparison of manufacturing choices (additive and traditional) ( a pilot study)
Get PDFThis research is built upon existing knowledge of additive manufacturing and traditional manufacturing to gain insights into the cost differences associated with different manufacturing processes as a pilot study. The researcher proposed a novel mathematical framework comprising a hybrid decision-making model comprising a linear optimization part entailed by the two distinct manufacturing procedures and an Analytical Hierarchical Process (AHP) part for choosing the best technology based on a set of qualitative factors. The model integrates diverse cost components, including but not limited to labor, materials, and equipment costs. Through a hybrid
decision-making model, the research study analyzes additive manufacturing and traditional manufacturing in light of quantitative factors (cost) and qualitative factors (quality, speed of production, sustainability, and flexibility). By using a pilot case study, the results suggest that AM provides a reduction in cost due to optimization in various cost components but also
considers TM as a preferable alternative over AM using the integrated qualitative criteria
Internal Needs Assessments: A worthwhile endeavor?
Get PDFIn 2020, the Oral Roberts University Library Needs Assessment Committee conducted six months of investigation, including an internal examination of the Library and an external study of Library resources, services, and staff. This Needs Assessment was unique in that a team of Library faculty and staff conducted it. Internal members of an organization rarely perform needs assessments for many reasons, including inherent bias and the potential distrust of those not on the assessment team. This process was complicated due to the COVID-19 pandemic during the period of data collection. The presenters will discuss the process, the benefits and some of the downsides of an Internal Needs Assessment. They will also describe how they navigated the tensions inherent in an internal assessment. Finally, they will present some of the recommendations that the Library has implemented. They will also explore some long-term benefits from a perspective three years later, and will discuss future plans.Ye
Receiver function imaging of deep and shallow subsurface structures of Oklahoma
Get PDFThe advancement of seismic imaging methodologies is driven by the requirement to attain a more comprehensive and accurate understanding of the subsurface, which holds significant importance for natural resource exploration, geohazard mitigation, and the interest of humanity about the geological history of the Earth and its prospective evolution. While active seismic imaging is dominantly applied in the exploration industry, passive seismic imaging methods which extract the subsurface information from natural sources (e.g., earthquakes, ambient noise, microseismism) offer nondestructive, economical access to the subsurface structures. Receiver function (RF) is an established passive seismic imaging method which traditionally reveals the deep-earth structure from teleseismic recordings. The abundance of earthquake sources around the world and established processing workflow makes the RF a promising method in investigating the upper mantle and crustal structure.
Oklahoma, situated geologically in the middle of the North American plate, has garnered significant attention from both the general public and the geoscience community due to the notable increase in intraplate seismicity over the past decade. However, our understanding of the deep structure of the Oklahoma crust and mantle remains limited, despite having approximate crust thickness estimates from seismic investigations on a continental scale. I address the crustal and mantle structure of the Oklahoma lithosphere by conducting teleseismic RF analysis in central Oklahoma, utilizing data from 169 broadband and short-period seismometers deployed by various monitoring networks. By converting the stacked RFs into the depth domain, this study provides the first detailed Moho map of central Oklahoma. The results indicate an eastward shallowing Moho, transitioning from over 50 km in the northwest to approximately 40 km in the east. Additionally, the RF depth cross-section reveals a mid-lithosphere discontinuity at a depth of 60-80 km within the upper mantle. Regarding the ongoing debate regarding the validation of midcontinent rift extension in Oklahoma over the gravity-anomalous zone, the RF analysis does not exhibit similar characteristics of crustal structure that are observed in the northern part of MCR, suggesting limited impact from the rifting processing within Oklahoma crust. However, the presence of intracrustal discontinuities observed in the RFs suggests the potential existence of rift-filling magmatism.
RFs derived from teleseismic events have limited capability in resolving shallow structures with high-resolution, primarily due to the absence of high-frequency components in teleseismic waveforms. Furthermore, deconvolution involving high-frequency component introduces instabilities to the inversion process and consequently less reliable RFs. To obtain high-resolution imaging of the shallow structures in the fault zone that ruptured the 2016 Mw 5.0 Cushing earthquake, I derived the RFs using local and regional earthquake data recorded by a nodal array comprising 130 portable seismic recording stations. A multichannel blind deconvolution approach is adopted to establish an inversion routine for retrieving high-resolution RF from local and regional earthquake data at a densely spaced array. The RFs clearly illustrate the primary conversion from the basement top interface, which cannot be observed from teleseismic RFs. The depth of this converted interface is approximately 1.15 km, which agrees well with an existing basement depth map.
Distributed Acoustic Sensing (DAS) from dark fiber introduces a new kind of data to the seismological community and holds great potential for earthquake detection applications. However, the earthquake wave responses of different DAS arrays may exhibit notable variations in signal to noise ratio and spectral sensitivity. These variations can be attributed to factors such as deployment conditions, surrounding noise levels, and fiber geometry. I present a comparative analysis of the waveforms of 2016 Mw 8.2 Alaska Peninsula earthquake from three DAS arrays (Enid, Ridgecrest, FORESEE-urban in State College). For comparison, waveform from nearby broadband stations is reviewed along with the converted particle velocity waveform from DAS strain and strain rate data. The three DAS arrays present the capability in capturing low-frequency signals while the variations of SNR exhibit between DAS arrays and internal sections, respectively. RF obtained from the combined Enid DAS array and conventional seismic receiver array show comparable conversion phases to those obtained from a broadband station
Everyone Belongs Here: Creating an Inclusive Public Library Local History and Genealogy Collection
No full textThe Chickasha Public Library maintains a local history and genealogy print collection that is currently being cataloged and organized. This presentation will give an overview of the process involved in creating original records with accurate and inclusive metadata and descriptions that reflect the history, perspective, and experiences of diverse groups so that all people can see both themselves and others accurately reflected in the collection
Flexible and optimal carbon dioxide capture system design for fossil-fueled power plants
Get PDFFossil fuel consumption remains a significant contributor to global greenhouse gas emissions, accounting for approximately 90% of the overall emissions, with fossil fuel power generation systems identified as a major source of CO2 emissions. Given the ongoing industrial activities and increasing energy demand, completely discontinuing the use of nonrenewable resources for power production is not feasible in the near future. CO2 capture and storage (CCS) technologies offer a promising option for continuing to utilize fossil fuels in a cleaner and more sustainable manner. The wide deployment of carbon capture technologies alone has the potential to decrease power plant emissions by as much as 90%. However, the current CCS technologies face several challenges for broad implementation, specifically significant energy requirements, high capital cost, and flexible operation. The current CCS technologies lead to a decrease in the net power output of the plant by approximately 25-40% and result in a substantial increase in power generation costs, potentially up to 70%. Another challenge is the requirement for flexible operation of CCS, as with the increasing penetration of renewable energy sources in the power grid, fossil fuel-fired power plants need to operate in a load-following manner to ease the integration of intermittent renewable sources. Consequently, significant fluctuations in the power plant flue gas necessitate flexible operation of the downstream carbon capture system to adapt to these changes.
The above challenges necessitate implementing innovative solutions in the operation and design of carbon capture systems to reduce the energy penalty and cost of CO2 capturing and improve the flexible operation of CCS to accommodate both base-load and load-following operating of the power plants. Membrane systems offer promising advantages for separating CO2 from other components of power plant flue gas, although the process encounters several technical and economic challenges. These challenges must be addressed to optimize their design and integration with fossil-fueled power plants and enhance the feasibility of this environmentally-friendly technology for extensive adoption.
This dissertation is focused on the development of flexible and efficient membrane-based carbon capture technologies for large-scale implementation and integration with both base-load and load-following fossil-fueled power plants under high renewable energy integration. This dissertation aims to address and provide insights into the current challenges by employing advanced modeling, simulation, and optimization techniques. An efficient and flexible multi-stage membrane-based CCS process is developed and optimized to address the challenge of energy requirements and cost penalties of the system. In this context, a comprehensive techno-economic model for the possible designs and operating strategies of the membrane separation process is developed in order to investigate the potential and viability of the membrane-based CCS system. Furthermore, the optimal process design and the possible trade-offs between performance indicators of the membrane-based CCS are presented with the aim of reducing energy and cost penalties. Finally, the transient behavior of the membrane-based process is further investigated at different disturbances and variations in the power plant operation imposed by the plant load-following behavior to address the required flexibility of the carbon capture system. The results substantiate that the proposed system could be an optimal and flexible option for the decarbonization of power plants operating in a load-following manner. The best possible trade-offs between objective functions show that the CO2 capture cost and energy penalty of the process could be as low as 13.1 /MWh and 101.66 $/tonneCO2, among the other CCS-equipped power plant.
The proposed designs and system investigation conducted in this dissertation and for addressing the technology challenges of the CO2 capture process hold considerable promise in facilitating the ideal reduction of carbon emissions from fossil-fueled power plants and promoting sustainability within the power sector. These advancements and developments, along with appropriate governmental policies and incentive programs, can potentially enhance the economic viability and desirability of CO2 capture systems, making them increasingly favorable for widespread implementation
Flute Choir as a Pedagogical Workshop: Case Studies in Youth, Collegiate, Community, and Advanced Adult Settings
Get PDFAcross the United States there are many flute ensembles that perform and rehearse with varying levels of experience. The purpose of this document is to argue the ultimate purpose of flute choir: to create a space for the development of flute musicianship and technique regardless of setting. The document provides flute pedagogy suggestions to aid in ensemble and individual member improvement utilized in ensembles across the settings and highlights transferable teaching points for flute choir directors, middle and high school band and orchestra teachers, composers of flute music, and to college music programs.
This resource provides a compilation of specific teaching ideas regarding ensemble and flute fundamental strategies gathered from seven reputable flute choir directors across the United States. Through interviews, these experienced directors described their groups, the goals they set, and the pedagogical strategies implemented to accomplish them. This compilation of pedagogical suggestions is organized by director and corresponding category of ensemble (youth, collegiate, community, and advanced adult). This resource will help flute choir directors of various settings establish their own workshops of flute pedagogy using suggestions that suit their style of ensemble to assist in achieving their goals effectively