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Calcareous Nannofossils and their Relationship with Climate Variability
No full textCalcareous nannofossils are what remains of calcareous phytoplankton after they die and find their way to the ocean floor. While these organisms are alive, they record changes in surface temperature of the ocean. For instance, Gephyrocapsa oceanica is strongly linked to warm ocean waters, whereas cooler waters are favorable for Gephyrocapsa muellerae. Calcareous nannofossils can also provide information about the availability of nutrients in surface waters. For example, Gephyrocapsa spp. (430 ka in age. Sea-surface temperatures were generally warm through this time interaval as the nannofossil assemblages are dominated by warm-water taxa such as Gephyrocapsa oceanica, Rhabdosphaera spp. and Helicosphaera spp. Cold-water species such as Coccolithus pelagicus and Gephyrocapsa muellerae appear for brief time periods throughout the studied interval. Surface water stratification increased through time, especially in the interval younger than 290 ka, based on high abundances of Florisphaera profunda and low N ratio values. These results suggest warmer and more oligotrophic waters dominated in the region over the last ~200 kyr
The Water-Energy-Carbon Nexus in Natural Gas Processing: Studying Interdependencies for Developing Waste Management Strategies
Get PDFNatural gas has proven to be a valuable energy source, enabling the transition to sustainable energy sources while gradually divesting from coal and oil. However, natural gas processing produces and utilizes significant amounts of energy, water, and carbon dioxide���all requiring judicious waste management for disposal or reuse. The quantities and characteristics of these resources are interdependent, and their presence is observable throughout the span of natural gas processing. For this reason, using a nexus approach to manage these resources represents an auspicious strategy for waste optimization.
In this work, several models are developed to quantify the interdependence between water, carbon dioxide, and energy in natural gas processing. The first model allows for the evaluation of CO��� fixation potential of carbon capture and utilization technologies using the limited information available at the early stages of technology development resulting in the development of the CO2Fix metric. This metric also provides a quantitative estimate for the energy required to fix CO��� through a CCU technology. The CO2Fix is coupled with a metric for evaluating the economic potential of chemical reaction processes, thereby constructing a model for commercial evaluation of carbon capture and utilization while considering carbon pricing and storage costs (Greenhouse gases Abatement, Sustainability, and Economics Framework [GASEF]). The last model presented in this research allows for the prediction of shale gas wastewater characteristics using spatiotemporal information on the production wells. The model was developed using a data analytics approach and covers specific plays/regions in Texas and Pennsylvania. Water treatment technologies are influenced by water quality, and predicting water quality with limited input information will facilitate the optimization of treatment strategies, thereby reducing energy consumption and CO��� emissions. The demonstration of CO2Fix and GASEF models has been carried out using sophisticated experimental campaigns to link the microscale kinetics and catalysis experimental studies with the macroscale model of novel and conventional technologies for CO��� utilization
Public and Stakeholder Engagement Summary: City of Jefferson, Texas December 2022
No full textThis public engagement report, a collaboration between Texas A&M University graduate students, Texas Target Communities, and the City of Jefferson, outlines the purpose, process, and findings of the public and stakeholder engagement process in Jefferson.
The Jefferson Economic Development Corporation (JEDCO) and the Jefferson City Council reached out to Texas Target Communities (TxTC) to conduct community engagement via public and stakeholder activities to hear directly from community members regarding the strengths, weaknesses, opportunities, and challenges in Jefferson. Community engagement was conducted via four activities ��� a public meeting, pop-up events, an online engagement website, and stakeholder interviews ��� designed to reach a diverse group to ensure an accurate representation of Jefferson���s population. The findings of this engagement effort seek to capture the current thoughts and opinions of the community and serve to set priorities for future growth. Public engagement and stakeholder interviews were conducted in October 2022
Exploration of Short-Term Variability of Sea States
No full textThis research utilizes an extensive dataset of over 40,000 sea state records along the UK coast to analyze the univariate and joint distributions of wave heights and periods, and recent theories on rogue waves. In the case of wave height distributions, the results reveal that the relative wave height HS/D can serve as a key indicator in model selection in a certain sea state. Naes model is found to be the most accurate in describing the tail of the wave height distribution for sea states with low relative wave heights (Hs/D 0.4). In between these sea states, a transition in the performance of the deep-water and the depth-dependent models is visible. When details of the spectrum are not available, the Weibull distribution is the most accurate amongst applicable models, despite considerable variability in its parameter values. Compared to wave height distributions, the joint distribution of wave heights and periods as well as period distributions, have received much less attention. The performance of widely used wave height-period joint distribution models are assessed using a dataset of the present scale for the first time. The objections raised by some researchers about previous studies with respect to the lack of sufficient resolution, stationarity and homogeneity in the data are addressed by employing a clustering approach. The results evidence the superiority of the model proposed by Zhang and Guedes Soares which improves upon the widely used Longuet-Higgins distribution. However, the marginal distributions of wave periods are found to deviate from the data. Empirical wave period relationships commonly employed in engineering design are evaluated and improved formulas incorporating spectral width are proposed. Turning to the study on rogue waves, wavelet analysis of surface elevation records shows that dispersive focusing is not exclusive to rogue wave occurrence. However, a correlation between the presence of increased energy in the vicinity of rogue waves and the abnormality index of the sea state is observed. Investigation of a probabilistic approach to predicting rogue wave risk suggests that relative depth KPD in the preceding 30 minutes can serve as a useful indicator
