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A carbon, nitrogen, and multi-isotope study of basalt glasses near 14°N on the Mid-Atlantic Ridge. Part B: Mantle source heterogeneities
No full textGeochemical variations along mid-ocean ridges reveal the heterogeneous nature of the convecting upper mantle and geodynamic evolution of our planet (e.g., Hofmann, 2007; Parai et al., 2012). Although the occurrence of incompatible element and isotopically enriched mid-ocean ridge basalts (E-MORB) commonly arises from interaction with nearby mantle plumes, the source of E-MORBs far from known hotspots is debated. A well-known example of an enigmatic geochemical enrichment is found at 14°N on the Mid-Atlantic ridge (MAR). This is also one of the few locations worldwide where volatile-saturated E-MORBs, often referred to as “popping rocks” (PR), have been recovered. Although the mechanism(s) involved in popping rock generation remain elusive, compressional regimes associated with the exhumation and formation of oceanic core complexes (OCC) may be required to produce popping rocks via protracted volatile accumulation. However, the geochemical signature of OCC samples and their potential relationship to local geochemical enrichments associated with popping rock-affiliated MORBs remain unknown. Here, we present a comprehensive volatile characterization of popping rocks and associated MORBs (n = 19) sampled at 14°N on the MAR, including (n = 2) normal MORBs (N-MORB) from an oceanic core complex (OCC) and (n = 17) E-MORBs (Bekaert et al., Part A). We use isotopic and abundance data for volatile (carbon, nitrogen, noble gases) and radiogenic (Pb, Sr, Nd) elements, as well as the abundances of major and trace elements, to elucidate on the source(s) of E-MORBs at 14°N and discuss the potential origin(s) of geochemical heterogeneities within the upper mantle. We observe co-variations of helium and radiogenic element isotopes, suggesting potential contributions from a young HIMU-type (high μ = time-integrated 238U/204Pb) component in the OCC mantle source. The mantle source of the OCC samples is clearly distinct from that of PR-affiliated samples, suggesting no genetic relationship between OCC samples and E-MORBs. In addition, elevated Dy/Yb in OCC samples likely point to the incorporation of a subducted crustal component that is not observed in the mantle source of other MORB samples analyzed in this study. We report mantle source 40Ar/36Ar variations at 14°N, which, in line with previous studies, are interpreted as primarily reflecting variations in the amounts of recycled atmospheric Ar. Despite extensive evidence for drastic geochemical heterogeneities at 14°N on the MAR, we observe no significant δ15N variation (average δ15N = -4.49 ± 1.40 ‰) across N-MORB and E-MORB samples. This is a fundamental constraint, as the absence of significant N isotope variations across the upper mantle may imply that sedimentary N (with a typical δ15N ∼ +6‰) is not extensively introduced within this reservoir during subduction. We investigate several scenarios that could explain this observation, including a significant contribution of altered oceanic crust to the overall budget of subducting slabs, quantitative return of subducting sedimentary N to the Earth\u27s surface by arc volcanism, and/or preferential transport/preservation of sedimentary N in the lower mantle source of oceanic island basalts
Hashi
No full textMontero and Takamatsu, both graduate students in Music, perform the program Hashi (Bridge in Japanese) which bridges cultures and combines traditional and contemporary composers from Japan and Latin America. The concert includes both solo and chamber music for classical guitar and piano which reflect cultural similarities and differences. With this duo project, Montero and Takamatsu aim to share their unique cultures through music and to reach out to a wide range of audiences from around the world. They believe it is a powerful way to connect with people from different backgrounds and bring them together through music. In the long run, this duo project will lay out the groundwork for further deepening the understanding of their cultures, explore them through music, and share their rich aspects
Momentum: Research & Innovation for Spring 2023
Get PDFThe Spring 2023 issue of Research & Innovation, a periodical focused on research at the University of Rhode Island
Making pictures: Disabled nonbinary praxis in Leslie Feinberg’s screened-in photography series
No full textThis paper expands historical and theoretical engagements with Leslie Feinberg’s life by analyzing the nonbinary and disability politics of hir screened-in photography series. Through a consent-based method called “making” photographs, Feinberg challenged the conventions of photographic representation of disabled and transgender people. The screened-in series provides a nonbinary political/relational model of gender, sexuality, race, and disability
Queer Mapping as Decolonial Praxis
No full textReview of Erotic Cartographies: Decolonization and the Queer Caribbean Imagination. Krystal Nandini Ghisyawan. New Brunswick, NJ : Rutgers University Press, 2022. ix + 247 pp
Crutch Design
Get PDFCrutches are commonly used across the world to provide assistance in mobility for people that have suffered leg injuries. Athletes are a great portion of the population that use crutches. In order for a leg injury to heal properly over time, there should not be any pressure going into the leg that has the injury. The process behind using crutches involves lacing your armpit on the top of the crutch and grabbing the handle that is connected across each upright. To walk, the user lifts the injured leg and applies pressure to the top of the crutch and grip handle. Then the user lifts the crutches and plants them out in front of their body, and takes a step through with the other non-injured leg. The pressure applied from the ground travels through the crutches and into the user’s armpits, wrists, and forearms. The objective for the project is to redesign the crutch to relieve the pressure that is exerted from the crutch into the user’s joints, and ultimately create a more comfortable crutch for people who have suffered from leg injuries. A prototype and final design report were created to further understand the task at hand and analyze the steps to be taken to achieve this goal of redesigning the modern crutch. This goal was achieved by adding large amounts of padding in the armpit support and handle to relieve pressure in the user’s armpit, wrists, and forearms, and also by replacing the bottom tip of the crutch with an attachable prosthetic blade that will act as a spring to alleviate pressure on the joints
Film Cut Down Device
Get PDFTeam 23, sponsored by TORAY, Innovation by Chemistry, is asked to find a solution to their scrap film roll problem. The problem is that at TORAY, there are times where a film roll doesn’t meet the expectations of their clients. This can happen for many reasons, such as unevenly applied film that bunches up in certain areas or quality not being up to par. Their current solution for this problem is to have someone utilize a box cutter, and work by hand on cutting the roll until all 10.8 meters of roll have been taken off the roll core. This process creates many problems for the company, such as safety risks and wasting man hours. Toray is looking for a solution that will drastically lessen the time it takes to cut the film down, with safety being paramount. Team 23, which includes John Halloran, Stephen Herchen, Josh Taylor, Yorke Pretorius and Will Sheldon, have successfully created certain parameters for this design to fit into. This required extensive research and dedication. The team has generated a wide range of possible solutions and narrowed down the most efficient design. With the design proving to work, the stages of a prototype are looking promising
MagSeal Design and Build of Seal Testing Device
Get PDFTeam 22, nicknamed The Fantastic Four, has been tasked with developing a tribology testing device for Magseal seals with a diameter of 1.5 . This project is being done in collaboration with Team 21, who is responsible for designing the seal that will be tested using Team 22\u27s device. The first step in this project was to gain an understanding of magnetic seals and tribology testing, which was achieved through literary and patent searches, as well as reviewing the work done by last year\u27s team, Team 18, known as The Challengers. The team was also given the opportunity to tour the Magseal facility and meet with their sponsors to gain a better understanding of their current testing machine and how the device they were creating should differ. Armed with this information, each team member generated 30 design concepts, resulting in a total of 150 designs. Using Pugh and QFD analysis, the team selected the top designs that focused on the design specifications given to them by Magseal.
These specifications included reaching a rotational speed of 7500 rpm, being able to apply 15 psi of pressure onto the seal, having a standardized seal mount that could exchange seal mounts easily, being lightweight and portable, and being able to generate 300°F of heat. Additionally, the device was required to have live data acquisition using a data logger.
During the first semester, Team 22 designed the skeleton of the device using paper and Fusion 360 software. They repurposed most of the previous year\u27s device, but scrapped a majority of it. The working prototype was made entirely of aluminum, with plans to partially redo it in steel to ensure a long-lasting machine. However, the device was unable to generate heat at this point, as it had not yet been integrated into the machine. While the motor could reach the required rpm, it generated a lot of vibration that would need to be addressed in the future. Despite these small issues, the prototype was deemed a success, providing a solid foundation for the team to build upon while staying within their budget.
Continuing into the second semester, Team 22 worked diligently to meet all the design specifications set by both the team and Magseal. After much deliberation and trial and error, the team was able to minimize vibration, which had been the main issue during the first semester. The device now met all the required specifications, including the desired rpm, a standardized seal mount, portability, longevity, at least 15 psi, and heat applied to the seal. The only outstanding issues were that the heating element had not been installed onto the device yet, and the weight of the device slightly exceeded the desired weight. However, given the recent changes and modifications, the weight was necessary and unavoidable.
Finally, live data acquisition was a challenge during the first semester, but the team worked tirelessly to develop adequate code for data collection and interpretation. After presenting the device in the Design Build Test Redesign Presentation to the class and showcasing it to peers, professors, and visitors, the device was deemed a success and approved by Magseal, including the company\u27s president