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Recovering Rare Earth Elements And Phosphates From Alternative Sources Using Novel Sorption Techniques
No full textRare earth elements (REEs) and phosphates are crucial non-renewable resources that have significant impacts on the economy due to their applications in critical areas such as technological advancements and the production of agricultural fertilizers. Recent geopolitical tensions have disrupted the global supply chain of REEs, leading to a shortage. Additionally, research studies have indicated that the phosphate reserves may become restricted to only a few countries in the near future, raising concerns about phosphate supply risk in the future. Thus, there is an urgent need to develop technologies that can recover REEs and phosphates from alternative domestic sources. Phosphate fertilizers are a main source of REE enrichment in agricultural fields, and recovering REEs from these fertilizers can help reduce REE contamination in the agricultural fields while providing an alternative source for REE recovery. In this dissertation, the following were addressed: (1) developing an efficient way to extract REEs from phosphate fertilizers, (2) developing a novel adsorption media to recover REEs from acidic leachate solutions, and (3) developing a sorption media for recovering phosphate from industrial and agricultural runoff. The thesis showed that phosphate fertilizers can contain up to 1100 mg kg-1 of REEs, and more than 85% of REEs can be extracted with 1.5M HCl within 20 minutes. Separation using the novel N,N,N′,N′‐Tetraoctyl Diglycolamide (TODGA) based solid-liquid adsorption media has increased the REE concentration in the final separated solution up to 10%. Furthermore, phosphates can be successfully recovered by the novel iron-coated bioadsorbents and can be used as fertilizers post-phosphate recovery
Computational Analysis Of Finite Size Air Filaments In Static Liquid
No full textThis study undertakes a numerical investigation of the dynamics of a finite-size air filament surrounded by a denser fluid medium with a range of viscosity. The two edges of the filament retract due to surface tension effects. It is shown that if the aspect ratio is small the filament recoil in a single bubble while for large aspect ratios the filament ruptures at its two ends. Between these two limits the filament can escape from pinch-off through the reopening of the neck and/or breakup in the middle region. The air filament pinch-off is accompanied by the formation of a thin air thread which subsequently breaks up into microbubbles. Viscous effects of the external fluid do not show a significant impact on the fate of large or small aspect ratio filaments but instead control the shape of the bulge and the neck region close to breakup. Before breakup, the bulge adopts a prolate shape for Ohnesorge numbers smaller than 0.01, while an oblate shape is obtained for Ohnesorge numbers larger than 1. A spherical shape is obtained between these two limits. For small Ohnesorge numbers the neck region exhibits a reflection symmetry perpendicular to the filament axis while for large Ohnesorge numbers a thread of air forms and connects the bulge to the filament. The radius of the neck is shown to decrease as a power-law function of the time before breakup with the exponent of 0.5 for small Ohnesorge numbers and 1 for large Ohnesorge numbers
Rational Design Of Novel Therapeutics Targeting Sars-Cov-2 Papain-Like Protease
No full textSARS-CoV-2, the virus responsible for COVID-19, poses an ongoing global health threat. Despite concerted efforts, containment remains elusive. To address this challenge, there is a pressing demand for drugs that utilize diverse mechanisms of action. In human coronaviruses (HCoV), the papain-like protease (PLpro) domain of Nsp3 is necessary for viral replication. Moreover, by interfering with host immunological responses by cleaving ubiquitin (Ub) and interferon-stimulated gene 15 protein (ISG-15) from host proteins, PLpro contributes to the cytokine storm linked to COVID-19. As a result, PLpro is a promising target for structure-based drug design. In this study, we have refined noncovalent and covalent inhibitors of SARS-CoV-2 PLpro from the primary literature, resulting in lead inhibitors with improved cytotoxicity and specificity while improving antiviral efficacy. We observe tight binding and engagement of the BL2 loop, BL2 groove, and Alpha cleft of PLpro, effectively obstructing the active site from natural substrates like ISG-15 and Ub. Studies on selectivity reveal very little off-target activity against the closest human structural homologs of PLpro. While there is high activity towards PLpro from SARS-CoV and SARS-CoV-2, it does not extend to MERS-CoV PLpro. These findings underscore the importance of investigating structurally diverse starting scaffolds for developing broad-spectrum HCoV PLpro inhibitors. These findings also expedite the structure-based design endeavors aimed at targeting PLpro to identify highly selective inhibitors with clinical significance
Case Study: Culturally Responsive School Leadership Employed During A Massive School – Merger/consolidation In A Large Southeastern Michigan Urban School District During Austere Times
No full textIn 2009, a major metropolitan urban school district in Southeastern Michigan, under state emergency management, implemented a massive school restructuring plan affecting 100+ elementary, middle, and high schools. The consequences of the plan included a high turnover rate of staff and students, violence at local school campuses, low morale among teachers and principals, and forced early retirement for many. The consolidation/merger process presented challenges for principals of merging schools who needed to adopt new leadership behaviors to manage their new school communities. This study aimed to identify Culturally Responsive School Leadership behaviors employed by three urban school principals and its impact on curricular decisions, students, parents, and community engagement levels. These principals created positive schooling experiences, increasing African American and Hispanic students, parents, and community engagement amidst challenges and while leading under state emergency management. The research focused on three principals’ implementation of Culturally Responsive School Leadership behaviors that contributed to positive educational experiences and increased engagement levels. The research revealed that: 1) participants showed various critical self-reflections on leadership and decision-making, 2) participants recognized the significance of integrating students\u27 indigenous social-cultural capital and community epistemologies, 3) participants were aware of the socio-economic status of their students and community, understood they could not continue with the limited historical role of schools, had to change the narrative by involving their school, creating overlapping spaces between the school and the community while using school spaces for students, parents, and community needs, 4) participants were aware of the historical marginalization and understood their communities’ lived experiences by employing their activism and advocacy to help their students and communities with social justice issues they were experiencing, 5) participants\u27 leadership background, personal experiences, and identities impacted their leadership behaviors, and 6) participants exhibited courageous leadership during uncertain times, fierce charter school competition, accountability, job insecurity, and neoliberal policies. The results of this study suggest Culturally Responsive School Leadership, specifically tailored and in harmony with the needs of African American students, parents, and communities, creates positive educational experiences and increased engagement
Topological Robustness Revealed By Real-Time Longitudinal And Transverse Studies
Get PDFFor a long time, phases of matter were interpreted through order parameters based on specific symmetries, with phase transitions involving symmetry breaking. However, the discovery of Integer Quantum Hall Effect (IQHE) with the Hall quantized resistances h/(ne^2) (n is a filling factor) has reshaped our understanding of phases and transitions. The effectis characterized by dissipationless edge states and insulating bulk states. These exotic properties are determined by a nontrivial topological invariant rather than an order parameter, and unchanged in the presence of perturbations. However, when measuring IQHE, there are two variations that require explanation. First, it is precision level of Hall quantized values. Second, the external factors, needed to break the quantum states, varies considerably and is sample-dependent. It tells us that robustness of quantum states is very different. To understand breakdown mechanism, the most way one focus on in recent years is edge studies, in which they explore any backscattering events that could affect the edge states. On the other hand, there are studies about bulk states, but they don’t include edge states. However, these two methods are separate, even though they investigate the same phenomenon. Therefore, they can’t explain the above variations. Motivated by this lack, this study investigates dynamics of topological breakdown including both bulk and edge states, simultaneously. An IQHE hosted in GaAs/AlGaAs heterostructure samples with Corbino geometry is deployed and brought to the breakdown by applying an in-plane electric field between inner and outer edges. A measurement technique is developed to probe the breakdown in both longitudinal and transverse directions at the same time. The results show that there is one-to-one bulk-edge correspondence participating in the breakdown. A global bulk-edge reconstruction model is proposed to explain the variations in robustness in terms of disorder and long-range screening effect due to electron-electron interaction. It turns out that the topological breakdown mechanism is the backscattering between reconstructed dissipationless currents of opposite chirality on opposite edges due to resonant tunneling effect through incompressible sites distributed randomly in the bulk when edge” states expand into the bulk under voltage bias