182 research outputs found
Thrust performance of isolated plug nozzles with two types of 40-spoke noise suppressor at Mach numbers from 0 to 0.45
Plug nozzles with two types of 40-spoke noise suppressor were tested at free-stream Mach numbers from 0 to 0.45 and over a range of nozzle pressure ratios from 1.5 to 4.0. In additon, an unsuppressed plug nozzle and a Supersonic Tunnel Association nozzle were also tested to provide baseline levels of thrust performance. The unsuppressed plug nozzle had an efficiency of 98 percent at an assumed takeoff pressure ratio of 3.0 and at Mach 0.36. At the same condition the suppressor nozzles had efficiencies of approximately 83.5 percent
Thrust performance of isolated 36-chute suppressor plug nozzles with and without ejectors at Mach numbers from 0 to 0.45
Plug nozzles with chute-type noise suppressors were tested with and without ejector shrouds at free-stream Mach numbers from 0 to 0.45 and over a range of nozzle pressure ratios from 2 to 4. A 36-chute suppressor nozzle with an ejector had an efficiency of 94.6 percent at an assumed takeoff pressure ratio of 3.0 and a Mach number of 0.36. This represents only a 3.4 percent performance penalty when compared with the 98 percent efficiency obtained with a previously tested unsuppressed plug nozzle
Thrust performance of isolated, two-dimensional suppressed plug nozzles with and without ejectors at Mach numbers from 0 to 0.45
A series of two-dimensional plug nozzles was tested with and without ejector shrouds at free stream Mach numbers from 0 to 0.45 and over a range of nozzle pressure ratios from 2 to 4. These nozzles were also tested with and without chute noise suppressors. A two-dimensional plug nozzle has an efficiency of 96.1 percent at an assumed takeoff pressure ratio of 3.0 and Mach 0.36. A 12-chute suppressed nozzle with sidewalls has an efficiency of 81.0 percent (15.1 percent below the unsuppressed nozzle)
Development and Validation of a New Hierarchical Composite End Point for Clinical Trials of Kidney Disease Progression
BACKGROUND: The established composite kidney end point in clinical trials combines clinical events with sustained large changes in GFR. However, the statistical method does not weigh the relative clinical importance of the end point components. A HCE accounts for the clinical importance of the end point components and enables combining dichotomous outcomes with continuous measures. METHODS: We developed and validated a new HCE for kidney disease progression, performing post hoc analyses of seven major Phase 3 placebo-controlled trials that assessed the effects of canagliflozin, dapagliflozin, finerenone, atrasentan, losartan, irbesartan, and aliskiren in patients with CKD. We calculated the win odds (WOs) for treatment effects on a kidney HCE, defined as a hierarchical composite of all-cause mortality; kidney failure; sustained 57%, 50%, and 40% GFR declines from baseline; and GFR slope. The WO describes the odds of a more favorable outcome for receiving the active compared with the control. We compared the WO with the hazard ratio (HR) of the primary kidney outcome of the original trials. RESULTS: In all trials, treatment effects calculated with the WO reflected a similar direction and magnitude of the treatment effect compared with the HR. Clinical trials incorporating the HCE would achieve increased statistical power compared with the established composite end point at equivalent sample sizes. CONCLUSIONS: In seven major kidney clinical trials, the WO and HR provided similar direction of treatment effect estimates with smaller HRs associated with larger WOs. The prioritization of clinical outcomes and inclusion of broader composite end points makes the HCE an attractive alternative to the established kidney end point
CsIâAntisolvent Adduct Formation in AllâInorganic Metal Halide Perovskites
The excellent optoelectronic properties demonstrated by hybrid organic/inorganic metal halide perovskites are all predicated on precisely controlling the exact nucleation and crystallization dynamics that occur during film formation. In general, highâperformance thin films are obtained by a method commonly called solvent engineering (or antisolvent quench) processing. The solvent engineering method removes excess solvent, but importantly leaves behind solvent that forms chemical adducts with the leadâhalide precursor salts. These adductâbased precursor phases control nucleation and the growth of the polycrystalline domains. There has not yet been a comprehensive study comparing the various antisolvents used in different perovskite compositions containing cesium. In addition, there have been no reports of solvent engineering for high efficiency in allâinorganic perovskites such as CsPbI3. In this work, inorganic perovskite composition CsPbI3 is specifically targeted and unique adducts formed between CsI and precursor solvents and antisolvents are found that have not been observed for other Aâsite cation salts. These CsI adducts control nucleation more so than the PbI2âdimethyl sulfoxide (DMSO) adduct and demonstrate how the Aâsite plays a significant role in crystallization. The use of methyl acetate (MeOAc) in this solvent engineering approach dictates crystallization through the formation of a CsIâMeOAc adduct and results in solar cells with a power conversion efficiency of 14.4%.It is found that unique adducts form between CsI and dimethyl sulfoxide (DMSO) and certain antisolvents, such as methyl acetate, during film formation of the allâinorganic perovskite CsPbI3. These adducts significantly influence crystallization and the power conversion efficiency of the resulting solar cells.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154525/1/aenm201903365-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154525/2/aenm201903365.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154525/3/aenm201903365_am.pd
CsIâAntisolvent Adduct Formation in AllâInorganic Metal Halide Perovskites
The excellent optoelectronic properties demonstrated by hybrid organic/inorganic metal halide perovskites are all predicated on precisely controlling the exact nucleation and crystallization dynamics that occur during film formation. In general, highâperformance thin films are obtained by a method commonly called solvent engineering (or antisolvent quench) processing. The solvent engineering method removes excess solvent, but importantly leaves behind solvent that forms chemical adducts with the leadâhalide precursor salts. These adductâbased precursor phases control nucleation and the growth of the polycrystalline domains. There has not yet been a comprehensive study comparing the various antisolvents used in different perovskite compositions containing cesium. In addition, there have been no reports of solvent engineering for high efficiency in allâinorganic perovskites such as CsPbI3. In this work, inorganic perovskite composition CsPbI3 is specifically targeted and unique adducts formed between CsI and precursor solvents and antisolvents are found that have not been observed for other Aâsite cation salts. These CsI adducts control nucleation more so than the PbI2âdimethyl sulfoxide (DMSO) adduct and demonstrate how the Aâsite plays a significant role in crystallization. The use of methyl acetate (MeOAc) in this solvent engineering approach dictates crystallization through the formation of a CsIâMeOAc adduct and results in solar cells with a power conversion efficiency of 14.4%.It is found that unique adducts form between CsI and dimethyl sulfoxide (DMSO) and certain antisolvents, such as methyl acetate, during film formation of the allâinorganic perovskite CsPbI3. These adducts significantly influence crystallization and the power conversion efficiency of the resulting solar cells.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154525/1/aenm201903365-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154525/2/aenm201903365.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154525/3/aenm201903365_am.pd
Controls on zooplankton methane production in the central Baltic Sea
Several methanogenic
pathways in oxic surface waters were recently discovered, but their relevance
in the natural environment is still unknown. Our study examines distinct
methane (CH4) enrichments that repeatedly occur below the thermocline during the
summer months in the central Baltic Sea. In agreement with previous studies
in this region, we discovered differences in the methane distributions
between the western and eastern Gotland Basin, pointing to in situ methane
production below the thermocline in the latter (concentration of CH4â
14.1±6.1 nM, ÎŽ13C CH4 â62.9 â°). Through
the use of a high-resolution hydrographic model of the Baltic Sea, we showed
that methane below the thermocline can be transported by upwelling events
towards the sea surface, thus contributing to the methane flux at the
seaâair interface. To quantify zooplankton-associated methane production
rates, we developed a sea-going methane stripping-oxidation line to determine
methane release rates from copepods grazing on 14C-labelled
phytoplankton. We found that (1)Â methane production increased with the number
of copepods, (2)Â higher methane production rates were measured in incubations
with Temora longicornis (125±49 fmol methane copepodâ1 dâ1) than in incubations with
Acartia spp. (84±19 fmol CH4 copepodâ1 dâ1) dominated zooplankton
communities, and (3)Â methane was only produced on a Rhodomonas sp.
diet, and not on a cyanobacteria diet. Furthermore, copepod-specific methane
production rates increased with incubation time. The latter finding suggests
that methanogenic substrates for water-dwelling microbes are released by cell
disruption during feeding, defecation, or diffusion from fecal pellets. In
the field, particularly high methane concentrations coincided with stations
showing a high abundance of DMSP/DMSO-rich Dinophyceae. Lipid biomarkers extracted
from phytoplankton- and copepod-rich samples revealed that Dinophyceae are a
major food source of the T. longicornis dominated zooplankton
community, supporting the proposed link between copepod grazing, DMSP/DMSO
release, and the build-up of subthermocline methane enrichments in the
central Baltic Sea.</p
The Role of Neighborhood Characteristics in Mortgage Default Risk: Evidence from New York City
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