Controls on carbonate precipitation in subsurface environments using microfluidics

Research on carbonate resevior is critical for advancing both enhanced oil recovery (EOR) and geologic gas storage, offering significant benefits in energy security and environmental sustainability. Carbonate formations, such as limestone and dolomite, make up over half of the world's petroleum reserves. These formations, hoIver, present challenges due to their complex and heterogeneous structures, which include variations in porosity and permeability. Advances in EOR techniques, such as CO₂ injection and low-salinity water flooding, help to overcome these challenges through enhancing the mobility of oil within these rock structures. Moreover, carbonate reservoirs hold enormous capacity for CO₂ storage, but are encumbered by their reactivity with CO₂ which raises questions on the long-term security of injected CO₂. Research in this field allows for the development of optimized EOR strategies that improve oil extraction in challenging carbonate settings and enables safe, long-term CO₂ storage, contributing to a balanced pathway toward a low-carbon future. First, I use a micromodel with pore geometry and geochemistry representative of geologic media to promote deep microbially-induced carbonate precipitation (MICP) penetration into subsurface formations as a natural approach to secure the geologic storage of gases (e.g., CO₂, H₂, CH₄). Cracks in embrittled Illbore cement, for example, provide a pathway for atmospheric gas leakage, while permeability heterogeneities in the storage reservoir leads to fingering effects that diminish the storage capacity. The design of MICP processes, hoIver, remains a challenge due to limited understanding of the coupled nonlinear reaction kinetics and multiphase transport involved. Specifically, previous attempts at MICP through porous media have been encumbered by carbonate precipitation localized to the first 1-3 cm of the bulk injection surface. I use a micromodel to image direct pore- and pore-ensemble-level mineral, fluid, and microbial distributions. An approach to adsorb microbes uniformly across the micromodel, rather than local accumulation near the inlet, is developed that enables deep MICP penetration into the porous medium. A sensitivity analysis was performed to investigate the impact of injection conditions (e.g., rates, concentrations) required to maximize CaCO₃ precipitation away from the injection site. With multiple cycles of MICP, a 78% reduction in permeability was achieved with ~ 8% carbonate pore volume occupation. Second, I present a novel improved oil recovery approach whereby MICP reduces the local permeability of water-saturated preferential flow paths to improve the overall sIep of the reservoir. Mobility contrasts betIen oil and water, along with permeability heterogeneity, lead to fingering instabilities that impede the recovery of hydrocarbons from the subsurface. With MICP, local pore geometry in preferential pathways are altered to divert successive injection fluids to oil-saturated pores. I demonstrate the feasibility of the approach using a silicon microfluidic device with etched geometries representative of real rock pores, where a ~ 5 % reduction in the porosity of preferential flow paths increased overall oil recovery by ~ 28 % original oil in place (OOIP). I performed a sensitivity analysis on the injection conditions required to maximize oil recovery and bacterial growth. Overall, I show that calcium carbonate grains grown using MICP can provide a secure and stable method to control fluid flow in situ and recover additional hydrocarbons to provide an avenue for cost-effective and environmentally-benign hydrocarbon extraction. Third, I functionalized a micromodel with dolomite to study the confinement integrity of formation during carbon dioxide storage and sequestration. Calcite was selectively precipitated along the edges of silicon grains, and dolomitized hydrothermally using a magnesium-rich fluid. Mineral dissolution and re-precipitation Ire observed through the microfluidic platform, and mineral composition evolution was characterized by using X-ray crystallography (XRD) and energy-dispersive spectroscopy (EDS). After dolomitization, the carbonate volume decreased by 14.5%, sligh higher than the 11%-14% reduction reported in previous studies. Insights into the dissolution and precipitation of the dolomite rind enhance our understanding of the diagenetic history of carbonate reservoirs, influencing interpretations of hydrocarbon potential and informing reservoir management strategies.Petroleum and Geosystems Engineerin

Expansion of Armatimonadetes through marine sediment sequencing reveals three classes with unique ecological roles

Marine sediments comprise one of the largest environments on the planet, and their microbial inhabitants are significant players in global carbon and nutrient cycles. With the advent of improved sampling techniques, recent scientific studies have shown the complexity of these communities and identified novel microorganisms from the ocean floor. Here we add to our understanding of understudied microbes by obtaining 77 metagenome-assembled genomes from the bacterial phylum Armatimonadetes in the Guaymas Basin, Gulf of California, and the Bohai Sea, coastal China. Seven of these MAGs are not classified at the class level. Thus, we propose to name these organisms Zipacnadia. Searches of public databases revealed that the 77 Armatimonadetes described in this study (including Zipacnadia) are globally distributed in hypoxic and anoxic environments and are dominant members of deep-sea sediments (up to 1.95% of the GB metagenomic raw reads). The Armatimonadetes described here also have unique metabolic capabilities for this phylum. They have pathways to reduce CO₂ to acetate via the Wood-Ljungdahl pathway (WLP) and generate energy through the oxidative branch of the Embden-Meyerhof-Parnas pathway using CO2 as an electron sink, maintaining the redox balance via WLP. Some of these organisms may also have an autotrophic lifestyle not previously identified in Armatimonadetes. Furthermore, these Armatimonadetes may play a role in sulfur and nitrogen cycling, using the intermediate compounds hydroxylamine and sulfite. The description of the Armatimonadetes identified in this study enhances our understanding of the diversity and metabolic potential of anoxic habitats worldwide.Marine Scienc

The lettuce monster : a history of state violence, carceral geography and industrial agriculture in the Salinas Valley

This dissertation is a descriptive account of state violence in the Salinas Valley, a rural agricultural area on California’s Central Coast, from the 1930s to the 2010s. Chapter 1 recounts the 1934 Filipino lettuce strike and the 1936 Dust Bowl migrant strike to track how valley law enforcement departments expanded in man- and fire-power, and instituted surveillance tactics that were advanced for their time. It also examines how agribusiness leaders funded and directed strike suppression activities, and facilitated law enforcement’s acquisition of tear gas and long-range guns. These events contributed to making Salinas Valley law enforcement one of the most armed and organized forces in the nation by the end of the 1930s. Chapter 2 highlights valley law enforcement’s partnerships with federal and military agencies during World War II, as well as agribusiness’s use of Bracero and Prisoner of War labor. This chapter argues that the Salinas Valley developed a carceral geography that enabled high levels of agricultural production during the war. Chapter 3 follows the transformation of the carceral geography to include field and factory worksites, as undocumented immigrants were housed in labor camps resembling prison camps and were surveilled by growers’ private security guards, regional Border Patrol agents, and United Farm Workers strikers. Undocumented immigrants constituted a marginalized workforce that was exploited and faced dangerous work and living conditions into the 1980s. Formerly incarcerated people also form part of this workforce, and are subject to hyper-surveillance inside agricultural packing factories, and in public spaces subject to city ordinances and state probation laws. Chapter 4 examines Salinas Valley law enforcement’s increased militarization post-9/11, which was facilitated by the expansion of the Department of Defense’s 1033 Program and state and federal funding. A culture of impunity in the valley enabled law enforcement to engage in a series of unethical policing practices and financial scams, ultimately escalating to a spate of police shootings from 2014 to 2019. This dissertation ends considering how current pandemic-related measures affect policing and surveillance in the valley.American Studie

On the Doppelperfekt in German dialects

This paper examines the periphrastic tense formation known as Doppelperfekt (DPF), used in various non-standard German dialects. The DPF, also referred to as doppelte Perfektformen, gesteigertes Perfekt, Perfekt II, and Ultraperfekt, involves adding an additional Partizip II of the auxiliary verb to a Perfekt construction. Examples include "Ich habe dem Kunden den Brief geschickt gehabt!" and "Er ist mit dem Zug angekommen gewesen." Historically marginalized in grammar books, the DPF's usage has often been overlooked. This study emphasizes the importance of non-standard tenses like the DPF for understanding language history and usage evolution. It explores the DPF's attributes, usage, history, and theorized origins, aiming to position the DPF within the German tense system both historically and in contemporary language.Germanic Studie

Does Cobalt Hexamine induce DNA-DNA Attraction? Investigations to Understand Nucleic Acid Compaction in the Cell

Nucleic acid compaction is a fundamental process in all living systems, exemplified by the tight packaging of DNA into chromatin in eukaryotic nuclei, as well as nucleic acid compaction in the viral capsid. The strong negative charge on the DNA backbone must be mitigated by positively charged species, including polyvalent ions and proteins, to achieve the necessary close packing. To dissect the electrostatic interactions driving DNA compaction, the xHEED (X-linking of Helices to measure Electrostatic Effects at Distance) method, previously developed in the Russell Lab, was used to measure distant-dependent interhelical encounter frequencies, and the atomic forces that mitigate these mechanisms as previous poisson-boltzmann models did a poor job of it. Rate constants were measured that reflect the equilibrium constant for transient DNA-DNA encounters under varying ionic conditions. Using the xHEED method, DNA-DNA crosslinking interactions were compared to DNA-Aldrithiol, a neutral molecule, to understand the effect of positive ions mitigating negative charge repulsion from the DNA Backbones. Previous work indicated that the maximal DNA-Aldrithiol neutral rate constant was 1.3 x 104 M-1s-1. This work indicated that crosslinking at moderate millimolar concentrations of Co(NH₃)₆³⁺ not only fully screen interhelical repulsion but also induce net attractions at higher concentrations, eventually reaching a plateau at 3.5 x 104 M-1s-1, faster than the neutral reaction, where further increases in Co(NH₃)₆³⁺ concentration have no additional effect. However, new work conducted in the lab indicates that the neutral rate constant at lower concentrations of Co(NH₃)₆³⁺ is lower than the maximal rate constant, indicating that there is still net attraction induced by Co(NH₃)₆³⁺ at lower concentrations, removing support for the net-neutral screening regime. Future side-by-side comparisons between cross-linked DNA and aldrithiol-mediated reactions at the same concentration of Co(NH₃)₆³⁺ are needed to fully clarify the impact of Co(NH₃)₆³⁺ on electrostatic interactions and the potential existence of an attractive regime. Measuring DNA-DNA crosslinking and comparing it to DNA-Aldrithiol at lower concentrations of Co(NH₃)₆³⁺ will clarify if Co(NH₃)₆³⁺ can induce attraction at lower concentrations of trivalent ions. This will refine understanding of in vivo DNA Compaction and provide further understanding on the role of multivalent compounds that naturally exist in the nucleus, such as spermine and spermidine.Biochemistr

An observational study on fathers’ self-disclosure and vulnerability in conversations with their adolescent children

Self-disclosure and vulnerability are two constructs that play an important role in relational intimacy. To date, almost no research investigates if or how fathers engage in self-disclosure or express vulnerability with their adolescent children. This study addresses this gap by providing a qualitative, thematic account of paternal self-disclosure and vulnerability obtained through observations of fathers engaging in conversations with their adolescent children. Results from this study suggest that, in certain contexts, fathers do self-disclose and express vulnerability with their adolescent children. Additionally, results from this study provide four distinct dimensions of self-disclosure that can be used for further research investigating individuals’ self-disclosure tendencies. Finally, several themes engorged from the data that demonstrate possible methods fathers can use to engage in self-disclosure and vulnerability with their adolescent children.Educational Psycholog

Development of a new laser doppler vibrometer-based non-contact damage detection system for cracks in rail head

Rail defects are one of the dominant causes of train derailments and an essential factor affecting transportation safety. Among the rail defects, transverse defects (TDs), which are cracks located transversely in rail heads, are one of the main causes of derailments. When TDs are left undetected, their size expands, leading to rail breaks. Therefore, the railway transportation community is interested in the detection of such defects at speeds that do not obstruct the routine railroad operation. The goal of this research is to develop a novel LDV-based noncontact damage detection system for TDs. The tasks performed herein to achieve this goal (i.e., the objective of the study) were: (i) extensive literature review and in-situ testing to understand the vibrations resulting from the propagating waves in rail, (ii) numerical modeling of the damage detection system, (iii) rigorous laboratory and in-situ testing to understand the noise in LDV measurements as well as to evaluate the performance of the damage detection system, and (iv) analytical work to develop filters to minimize the noise in the LDV measurements. Accordingly, the configuration of the developed damage detection consists of two LDVs attached vertically in front of a rail car to measure guided waves in the rail head, which are induced by rail-wheel interaction. This system uses the LDV measurements to detect a change in the relative amplitudes of the recorded waves caused by a defect in the frequency range between 30 kHz to 100 kHz. The lower cut-off frequency was selected conservatively since it was shown in the literature that guided waves start to localize in the rail head after approximately 15 kHz. The higher cut-off frequency was selected since (i) the guided waves below 100 kHz can be used for transverse defect detection (as the frequency exceeds 100 kHz, waves are susceptible to surface defects), and (ii) the measurements collected from rail during the passage of operating trains showed that the power of the excitations induced by wheel-rail interactions is dominant up to approximately 100 kHz. The main challenge during the development of the system was speckle noise, which is inevitable due to the inherent nature of the measurements performed by LDVs placed on a moving platform. Consequently, the damage detection framework associated with the system operates as follows: 1) in the pre-processing stage, time-varying mean and impulsive noise in the recorded LDV signals are filtered and then the changes in the LDV signals in the frequency range of interest are quantified and monitored using moving standard deviation, 2) in the post-processing stage, two damage features, which are based on the relative change in the moving standard deviations and transfer functions between two measurement points are combined using multivariate statistical analysis to create a damage index that shows the location of rail segments which are affected by a defect. The goal of impulsive noise filtering and transfer functions in the framework is to minimize the speckle noise. The field tests demonstrated that rail segments consisting of a defect can be identified by the developed system.Civil, Architectural, and Environmental Engineerin

Under the aegis of the Archangel : fascism and divine kingship in interwar Romania

This report aims to take a decisive first step towards an analysis of fascism as a resuscitated form of that archaic political figuration known to religious studies scholars as divine kingship. I take this aspirational first step through a case study of The Legion of the Archangel Michael and Corneliu Zelea Codreanu, Romania’s interwar fascist movement and its founder. The report first situates itself within the ‘new consensus’ of fascist studies as represented by the theories of Roger Griffin and Emilio Gentile before delving into a history of the Legion of the Archangel Michael and C.Z. Codreanu. With this historical data in hand, I turn to an exegesis and application of some key theories on divine kingship from Ernst Kantorowicz’s The King’s Two Bodies (1957) and David Graeber & Marshall Sahlins’ On Kings (2017) to the Legion. What emerges is a distinct vision of the necessarily modern political phenomenon of fascism as in fact a kind of reboot of divine kingship for an era of mass, electoral politics.Religious Studie

Factors associated with food delivery app use in young adults

Food delivery apps are highly popular among young adults and are often used to purchase calorie-dense foods, which are associated with a variety of health issues such as increased risk for obesity. Limited research exists on the use of food delivery apps and the research that has been conducted, focused on adults, suggests that food delivery app use differs by sociodemographic factors. Thus, the purpose of this study is 1) to describe food delivery app use among young adults, and 2) to examine the association between young adult food delivery app use and factors including age, race, ethnicity, sex, SES, food insecurity, living arrangement, financial responsibility, and full-time student status. Data are from the Promoting Young Adult Health Survey, a cross-sectional online survey with 1,038 young adults online from the Qualtrics panel January-February 2022. Poisson regression was used to examine the relationship between food delivery app use and the sociodemographic variables. Our results suggest that participants who reported being non-Hispanic Black and Hispanic had greater food delivery app use frequency as compared to participants who reported being white. Having higher perceived subjective social status, being food insecure, being financially responsible, and being a full-time student were all significantly associated with greater food delivery app use frequency. Living with someone else was significantly associated with lower food delivery app use frequency. Age, sex, and ‘Other’ Race/ethnicity were not associated with food delivery app use frequency. Overall, young adults use food delivery apps approximately twice a week with vulnerable groups such as Black and Hispanic young adults and young adults reporting food insecurity having greater frequency of use. This study provides a first step in understanding the characteristics of young adults who use food delivery apps more frequently. Given that this new technology can both increase access to unhealthy food options as well as healthy food options, future research is needed to better understand the types of food purchased through food delivery apps and the differences by the sociodemographic factors explored in this study.Kinesiology and Health Educatio

Methods for matrix completion

In this paper, we are going to provide major results for two sorts of Matrix Completion problems. One involves the recovery of a low rank matrix and the other involves the recovery of an approximately low rank matrix based on a small number of observed entries. In the end of the paper, we are going to demonstrate the feasibility of the recovery methods discussed on randomly generated low rank and approximately low rank matrices.Computer Scienc