In exchange

This thesis parses the dynamics of emotional labor in personal relationships. By bringing softness, connection and exposure to the viewer’s body in the form of tactile experience and wearable sculpture, this book and the installation that it accompanies provide a physical lens through which to consider the challenges of reciprocity and the emotional experiences at that are at stake in a struggle for balance and mutuality in relationships

Depositional characteristics of \u3csup\u3e7\u3c/sup\u3eBe and \u3csup\u3e210\u3c/sup\u3ePb in southeastern Michigan

The depositional fluxes in the bulk and dry fallout as well as the concentrations of 7Be and 210Pb in aerosols were measured for a period of 17 months at Detroit, Michigan. The bulk depositional fluxes of 7Be and 210Pb varied between 3.11 and 63.0 dpm cm−2 yr−1 (mean of 11.4 dpm cm−2 yr−1) and 0.35 and 10.3 dpm cm−2 yr−1 (mean of 1.41 dpm cm−2 yr−1), respectively, and this variability in the depositional fluxes is attributed to the frequency and amount of precipitation and seasonal variations in the depositional fluxes. The dry depositional fluxes of 7Be and 210Pb contributed 2.1–19.8% and 3.6–48.6% of the bulk depositional fluxes, respectively. The higher precipitation-normalized enrichment factor for 7Be during spring is attributed to the stratosphere-troposphere exchange of air masses during spring and large-scale atmospheric mixing during summer. We report that snow is more efficient than rain in removing 210Pb from the atmosphere, and this is likely due to higher surface area of snow flurries compared to the rain droplets. The volume-weighted concentrations of 7Be and 210Pb are the highest reported in literature so far. The concentration of 7Be in the air showed a seasonal increase during the spring and summer months, and no seasonal variation was observed for 210Pb. The mean deposition velocities of aerosols calculated using concentrations of 7Be and 210Pb in air and precipitation are 1.6 and 1.1 cm s−1, respectively, and the corresponding washout ratios are 948 and 637. There is no significant correlation between the aerosol mass and depositional velocities of 7Be and 210Pb in the air masses. We propose that a relatively minor portion of the aerosols actively participate in the removal of these nuclides from the air masses

Residence times and temporal variations of \u3csup\u3e210\u3c/sup\u3ePo in aerosols and precipitation from southeastern Michigan, United States

Daughter products of 222Rn (such as 210Pb, half-life = 22.1 years, and 210Po, half-life = 138 days) have been widely used as tracers to determine the removal rates of aerosols as well to obtain analog information on the behavior of other chemical species in the lower atmosphere. To establish the first data set on the depositional fluxes of 210Po in bulk precipitation and concentrations in air samples from the midwestern United States, we measured the depositional fluxes of 210Pb and 210Po in the bulk (wet plus dry) and dry fallout by deploying a rain collector (dry and bulk) for a period of 17 months. We also collected 30 aerosol samples during this period to assess the temporal variations of these nuclides in the surface air in Detroit, Michigan. The activity of 210Po in the surface air ranged from below detection limit to 0.118 mBq m−3 (mean of 0.072 mBq m−3). The specific activities of 210Po and 210Pb in aerosols ranged between 0.28 and 4.48 Bq g−1 (mean of 0.87 Bq g−1) and 2.7 and 30 Bq g−1 (mean of 13.6 Bq g−1), respectively; these values are about 1–2 orders of magnitude higher than the surface soil. The mean activity ratios of 210Po/210Pb in the bulk precipitation and dry fallout were found to be 0.049 (n = 27) and 0.25 (n = 8), corresponding to residence times of 15 and 75 days, respectively. Higher values in the dry fallout are attributed to resuspension of very fine older material from the ground. The 210Po/210Pb activity ratios in the aerosols varied between 0 and 0.210 (mean of 0.075), with corresponding residence times of 0–61 days (mean of 22 days). The mean deposition velocity and bulk washout ratio obtained using 210Po is compared with those obtained for 210Pb. From the measured aerosol mass concentrations and calculated values of the depositional velocity, the calculated depositional fluxes of aerosols are reported

The Effect of Using Virtual Manipulatives on Students’ Ability to Mentally Compare Proper Fractions

This study proposes a method to analyze the effects of the use of virtual fraction models (circle/bar/number line) on students’ ability to mentally compare proper fractions. Since developing a sense of magnitude with both whole numbers and rational numbers is highly correlated with improved performance on standardized assessments and improved performance in later algebra classes, special attention is directed to the bar and number line as they are linear representations. The study used an experimental pretest/posttest group design by randomly assigning subjects within class sections to a control group (physical fraction circles) and treatment groups with seven different methods of comparing fractions (virtual fraction circle, virtual bar model, virtual number line, and all combinations). The pretest and posttest instruments identifying student reasoning in fraction comparison used in the study were developed by the Education Development Center’s Eliciting Mathematics Misconceptions Project. The instruments were designed to gauge students’ dependence on whole number reasoning, the unit fraction, and gap reasoning (the difference between the numerator and denominator) The use of the virtual fraction circle should determine whether a technology bias is inherent in the study, while the bar model and the number line model show a more linear view of the fractions. A t-test showed significant improvement in the overall sample, but analysis of variance by manipulative on the differences between pretest and posttest scores and the differences between a pre/post classification on a scale of student comparison method showed no significant differences between the manipulatives

Atomic Layer Deposition for Fabrication of Advanced Polymer Electrolyte Membrane Fuel Cell Catalysts

Polymer electrolyte membrane fuel cells (PEMFCs) are highly-efficient devices that convert the chemical energy stored in hydrogen and oxygen into electricity. The commercialization of this technology is hindered by the use of platinum metal to catalyze the oxygen reduction reaction (ORR) on the cathode. In this work, atomic layer deposition (ALD) was applied to the fabrication of PEMFC catalysts in order to improve the utilization of Pt in the ORR as well as the stability of the catalytic Pt nanoparticles over voltage cycling. Nanostructures of TiO2 were added via ALD to carbon-supported Pt catalysts (Pt/C) in order to investigate their stability effects. The durability of the catalysts was enhanced by the addition of TiO2, with up to 70% retention in mass activity recorded over voltage cycling of the coated materials. A high-temperature treatment was found to produce Pt-Ti nanoparticles with high initial activity, but very poor durability. Atomic layer deposition was also used to add WN nanostructures to the catalysts. After a high-temperature treatment, highly stable W2N blocking structures were formed around the Pt nanoparticles, which produced a catalyst with high activity and durability. Additional testing of these materials in a PEMFC showed that the addition of ALD nanostructures had significant effects on catalyst layer hydrophobicity, which has implications for water management during fuel cell operations. In order to improve the utilization of Pt in the ORR, extended thin film electrocatalyst structures (ETFECS) were designed through the application of Pt ALD to a Ni nanowire (NiNW) substrate. Following a thermal annealing process to compress the lattice of the deposited Pt, the ETFECS were found to be 4 times more active than nanoparticle Pt catalysts. Upon further testing in a PEMFC, the performance of these ALD materials surpassed that of previously-reported ETFECS as well as the DOE 2020 target for fuel cells. Additional research was conducted to develop a bimetallic Pt-Ni ALD process for ETFECS. It was observed that the quantity of deposited metal can be finely tuned by adjusting the ALD parameters, but further work will be required to improve the final performance of the materials produced through this method.</p

Sources of land-derived runoff to a coral reef-fringed embayment identified using geochemical tracers in nearshore sediment traps

This paper is not subject to U.S. copyright. The definitive version was published in Estuarine, Coastal and Shelf Science 85 (2009): 459-471, doi:10.1016/j.ecss.2009.09.014.Geochemical tracers, including Ba, Co, Th, 7Be, 137Cs and 210Pb, and magnetic properties were used to characterize terrestrial runoff collected in nearshore time-series sediment traps in Hanalei Bay, Kauai, during flood and dry conditions in summer 2006, and to fingerprint possible runoff sources in the lower watershed. In combination, the tracers indicate that runoff during a flood in August could have come from cultivated taro fields bordering the lower reach of the river. Land-based runoff associated with summer floods may have a greater impact on coral reef communities in Hanalei Bay than in winter because sediment persists for several months. During dry periods, sediment carried by the Hanalei River appears to have been mobilized primarily by undercutting of low 7Be, low 137Cs riverbanks composed of soil weathered from tholeiitic basalt with low Ba and Co concentrations. Following a moderate rainfall event in September, high 7Be sediment carried by the Hanalei River was probably mobilized by overland flow in the upper watershed. Ba-desorption in low-salinity coastal water limited its use to a qualitative runoff tracer in nearshore sediment. 210Pb had limited usefulness as a terrestrial tracer in the nearshore due to a large dissolved oceanic source and scavenging onto resuspended bottom sediment. 210Pb-scavenging does, however, illustrate the role resuspension could play in the accumulation of particle-reactive contaminants in nearshore sediment. Co and 137Cs were not affected by desorption or geochemical scavenging and showed the greatest potential as quantitative sediment provenance indicators in material collected in nearshore sediment traps

Performative Identity in Djuna Barnes\u27 The Ladies Almanack and Nightwood

This thesis discusses performative identity in Djuna Barnes\u27 The Ladies Almanack and Nightwood. Barnes\u27 characters create and perform their identities as an attempt to escape or subvert patriarchal norms and societal prejudices. In analyzing the marginalized performative identity categories (race, class, gender, sexuality), one can glean an understanding of the complex social tensions present during Barnes\u27 era, and understand the socially constructed, confining nature of identity itself