Far-Field Species Distribution Measurements on the BHT-600 Hall Thruster Cluster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76148/1/AIAA-2007-5304-543.pd

Top hat electrostatic analyzer for far-field electric propulsion plume diagnostics

The design, development, and testing of the top hat electric propulsion plume analyzer (TOPAZ) are presented for far-field electric propulsion plume diagnostics. The trend towards high-power thruster development will require plume diagnostic techniques capable of measuring high-energy particles as well as low-energy ions produced from charge-exchange collisions due to elevated facility background pressures. TOPAZ incorporates a “top hat” design with a geometrical analyzer constant of 100 resulting in a wide energy range and a high-energy resolution. SIMION, an ion trajectory analysis program, was used to predict characteristics of the analyzer. An ion beam accelerator system confirms the computational results. TOPAZ provides an energy resolution of 2.7%, field of view of 112°×26°112°×26° (azimuthal by elevation) with an angular resolution in each direction of 2°, and a demonstrated energy-per-charge acceptance range of 5–15 keV5–15keV. An energy profile measurement of the NASA-173Mv1 Hall thruster demonstrates instrument operation in a Hall thruster plume.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87897/2/013505_1.pd

Octogenarians with blunt splenic injury: not all geriatrics are the same.

Geriatric trauma patients (GTP) (age ≥ 65 years) with blunt splenic injury (BSI) have up to a 6% failure rate of non-operative management (NOM). GTPs failing NOM have a similar mortality rate compared to GTPs managed successfully with NOM. However, it is unclear if this remains true in octogenarians (aged 80-89 years). We hypothesized that the failure rate for NOM in octogenarians would be similar to their younger geriatric cohort, patients aged 65-79 years; however risk of mortality in octogenarians who fail NOM would be higher than that of octogenarians managed successfully with NOM. The Trauma Quality Improvement Program (2010-2016) was queried for patients with BSI. Those undergoing splenectomy within 6 h were excluded to select for patients undergoing NOM. Patients aged 65-79 years (young GTPs) were compared to octogenarians. A multivariable logistic regression model was used to determine the risk for failed NOM and mortality. From 43,041 BSI patients undergoing NOM, 3660 (8.5%) were aged 65-79 years and 1236 (2.9%) were octogenarians. Both groups had a similar median Injury Severity Score (ISS) (p = 0.10) and failure rate of NOM (6.6% young GTPs vs. 6.8% octogenarians p = 0.82). From those failing NOM, octogenarians had similar units of blood products transfused (p > 0.05) and a higher mortality rate (40.5% vs. 18.2%, p < 0.001), compared to young GTPs. Independent risk factors for failing NOM in octogenarians included ≥ 1 unit of packed red blood cells (PRBC) (p = 0.039) within 24 h of admission. Octogenarians who failed NOM had a higher mortality rate compared to octogenarians managed successfully with NOM (40.5% vs 23.6% p = 0.001), which persisted in a multivariable logistic regression analysis (OR 2.25, CI 1.37-3.70, p < 0.001). Late failure of NOM ≥ 24 h (vs. early failure) was not associated with increased risk of mortality (p = 0.88), but ≥ 1 unit of PRBC transfused had higher risk (OR 1.88, CI 1.20-2.95, p = 0.006). Compared to young GTPs with BSI, octogenarians have a similar rate of failed NOM. Octogenarians with BSI who fail NOM have over a twofold higher risk of mortality compared to those managed successfully with NOM. PRBC transfusion increases risk for mortality. Therefore, clinicians should consider failure of NOM earlier in the octogenarian population to mitigate the risk of increased mortality

The Top Hat Electric Propulsion Plume Analyzer (TOPAZ): Preliminary Data on the BHT600 Cluster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76496/1/AIAA-2005-3870-173.pd

Development of the Top Hat Electric Propulsion Plume Analyzer (TOPAZ)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77063/1/AIAA-2004-4099-811.pd

Effect of Backpressure on Ion Current Density Measurements in Hall Thruster Plumes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76301/1/AIAA-7713-781.pd

Protective Places: the Relationship between Neighborhood Quality and Preterm Births to Black Women in Oakland, California (2007–2011)

Black women have the highest incidence of preterm birth (PTB). Upstream factors, including neighborhood context, may be key drivers of this increased risk. This study assessed the relationship between neighborhood quality, defined by the Healthy Places Index, and PTB among Black women who lived in Oakland, California, and gave birth between 2007 and 2011 (N = 5418 women, N = 107 census tracts). We found that, compared with those living in lower quality neighborhoods, women living in higher quality neighborhoods had 20–38% lower risk of PTB, independent of confounders. Findings have implications for place-based research and interventions to address racial inequities in PTB

Analytical modeling for the heat transfer in sheared flows of nanofluids

We developed a model for the enhancement of the heat flux by spherical and elongated nano- particles in sheared laminar flows of nano-fluids. Besides the heat flux carried by the nanoparticles the model accounts for the contribution of their rotation to the heat flux inside and outside the particles. The rotation of the nanoparticles has a twofold effect, it induces a fluid advection around the particle and it strongly influences the statistical distribution of particle orientations. These dynamical effects, which were not included in existing thermal models, are responsible for changing the thermal properties of flowing fluids as compared to quiescent fluids. The proposed model is strongly supported by extensive numerical simulations, demonstrating a potential increase of the heat flux far beyond the Maxwell-Garnet limit for the spherical nanoparticles. The road ahead which should lead towards robust predictive models of heat flux enhancement is discussed.Comment: 14 pages, 10 figures, submitted to PR

Ion-Energy Plume Diagnostics on the BHT-600 Hall Thruster Cluster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76547/1/AIAA-20514-735.pd