An Optically Pumped Comagnetometer for High-sensitivity RF Detection without Magnetic Shielding

We develop an optically-pumped magnetometer (OPM) sensitive in the radiofrequency( RF) regime based on 85Rb in a natural abundance rubidium vapor cell to operate in dynamic geomagnetic field environments. Because high sensitivity operation of RF OPMs requires control of the magnetic field environment near DC, we develop an OPM comagnetometer that also utilizes the 87Rb present within the same vapor cell to implement a secondary OPM variometer that provides information on the field-environment near DC. This information is used to provide feedback via a set of tri-axial field control coils that counters the unwanted effects of external geomagnetic fields from DC to 60 Hz, which in turn allows RF OPM operation with an intrinsic sensitivity of around 9 fT/√Hz presence of external magnetic fields on the order of 10s of µT

The Role of Gender and Salient Social Identities in Producing Vulnerability and Maladptation to Flooding in Koraso, Berekum, Ghana

This paper highlights how social identities like polygamy, illiteracy, and ethnicity hinder rural women farmers in Ghana from adapting to climate change. It advocates for an intersectional approach to address these challenges, moving beyond simplistic gender binaries. Using qualitative interviews (n=49) in a flood-prone village in Berekum, Ghana, the study reveals how these identities intersect with gender roles and colonial legacies, exacerbating vulnerability. It bridges Black feminist thought with climate change, an underexplored area, offering insights into climate change and environmental studies, as well as Black feminist scholarship. This research urges a reevaluation of how we understand climate change in relation to race, gender, and other social identities

IMMUNE CELL BALANCE IN CHRONIC HYPOXIA INDUCED PULMONARY HYPERTENSION

Chronic hypoxia (CH), caused by sleep apnea, chronic obstructive pulmonary disease, or high-altitude exposure, leads to pulmonary hypertension (PH). The pathogenesis of CH-induced PH has a number of hallmarks, including phenotypic changes in the pulmonary smooth muscle cells, arterial wall thickening, enhanced vasoreactivity, and inflammation around the pulmonary arteries. Utilizing a T regulatory (Treg) cell lineage tracking mouse model, this dissertation sought to further establish the importance of Treg and T helper 17 (TH17) cell balance in CH-induced PH. We demonstrated that Treg number and suppressive capacity decrease, TH17 cells increase, and Treg-to-TH17 cell transition occurs following exposure to hypoxia. We also show evidence that inducing tolerance to collagen type V (col V), a known self-antigen, attenuates indices of CH-induced PH. Altogether, this work further elucidates the mechanisms of the inflammatory response and possible therapeutic targets for preventing and treating CH-induced PH

Fault Location in DC Microgrids using Traveling Waves

In DC power systems, rapid fault location is crucial for maintaining reliable operation, particularly with the prevalence of DC-DC converters. This study investigates fault location techniques in DC systems utilizing Traveling Waves (TWs). Following data normalization, multi-resolution analysis employs discrete wavelet transform to capture high-frequency patterns of TW\u27s wavelet coefficients. Parseval\u27s theorem is utilized to quantify the energy of these coefficients. First, a curve-fitting technique is employed to estimate fault locations in DC microgrids. Then, two transfer learning approaches are proposed: first approach integrates Parseval energy curves into a Gaussian process estimator, while second employs feedforward neural network for fault prediction. Hardware implementation of TW protection device is also explored, involving real-world testing and validation in the Emera Technologies Kirtland Airforce Base low-voltage DC microgrid. Through experimental validation and field tests, the effectiveness of the proposed methodologies in achieving fast and accurate fault location in DC power systems is demonstrated

IF THE SHREW FITS, SEQUENCE IT: THE HISTORICAL BIOGEOGRAPHY OF EURASIAN SHREWS

Eurasia\u27s ancient geology and extreme environments, combined with diverse topography and Quaternary climate oscillations, have significantly influenced the genetic structure of its fauna. Unlike Europe and North America, much of high latitude Asia remained ice-free during glaciation, allowing species to persist more widely. However, this region has received limited research attention. In my study, I examined shrews in the Sorex ‘caecutiens’ and ‘minutus’ groups to understand genetic relationships across Eurasia. Using mitochondrial cytochrome b gene data, I identified well-supported phylogenetic relationships and found that Pacific Coastal Archipelagos played a key role in shrew diversification. Additionally, a longitudinal gradient of genetic diversity was observed, reflecting east-west population expansions during the Late Pleistocene. This contrasts with the northward expansion seen in European and North American species. My findings provide new insights into the historical biogeography of a minimally studied region of Asia

Solderability of Additively Manufactured Metals and the Effect of Surface Modification

The enhanced geometrical design freedoms enabled by additive manufacturing (AM) are of particular interest in producing components for electrical and thermal applications. Copper (Cu) is an excellent conductor, but it is relatively unexplored in AM. For effective use in electrical and thermal assemblies, AM Cu requires further study. In the present work, the bulk and surface properties as well as the solderability of AM Cu produced by laser powder bed fusion (LPBF), directed energy deposition (DED), and bound powder extrusion (BPE) has been characterized. Additionally, the surface properties, effect of electroplating, and the solderability of AM 17-4 PH stainless steel are explored. LPBF Cu and nickel plated 17-4 PH wet very well with eutectic Tin-Lead (SnPb) solder, but BPE Cu was determined to have the best overall solderability. Surface modification by dry electropolishing is shown to decrease the surface roughness and improve solderability

Active Brazing of Single Crystal Al2O3 to Kovar Alloy with AgCuZr Filler Metal

Brazing provides high strength and hermetic joining between metal, ceramic, and composite materials. Origins of the brazing process trace back to 3000BC, yet the technique continues to maintain relevance and demand across aerospace, medical, electronic, optical, and mechanical engineering. Here, single crystal Al2O3 (sapphire) was joined to Kovar in a single step via an AgCuZr active braze filler metal. The microstructure of the completed joint was investigating using microscopy and spectroscopy techniques. A unique braze chamber, paired with an optically clear top substrate (sapphire), allowed further investigation into the dynamics of the active braze process via in situ video monitoring. The collected video data was used to select five quench points in the prescribed thermal cycle ramp. Each quenched sample underwent postmortem microscopy and spectroscopy analysis, making it possible to track microstructure evolution across the thermal cycle. In situ monitoring provided new insight into the reactions that occur in active braze joining, especially at the interface between the filler metal and Al2O3 substrate, and provides a method for real-time investigation of brazing parameters moving forward

TEACHER-IMPLEMENTED SCAFFOLDING

Teacher-implementing scaffolding is fundamental in teaching that was disrupted by the sudden move to emergency remote teaching during the pandemic.  A review of research found trends based on grade and subject and that teacher’s responsiveness was the main contingent processes reported.  Based on this a survey was developed and an exploratory factor analysis was completed.  An analysis of the survey results found differences in teacher agency, self-efficacy, and the supports used when comparing in-person and online teacher-implemented scaffolding.  Qualitative results further support findings and describe teachers’ perspective on the change to the environment, adaptations made, and hinderances noted while supporting student learning while online

2023/2024 UNMV Art Studio AA Assessment

https://digitalrepository.unm.edu/provost_assessment/4220/thumbnail.jp