5,238 research outputs found
Study of orifice fabrication technologies for the liquid droplet radiator
Eleven orifice fabrication technologies potentially applicable for a liquid droplet radiator are discussed. The evaluation is focused on technologies capable of yielding 25-150 microns diameter orifices with trajectory accuracies below 5 milliradians, ultimately in arrays of up to 4000 orifices. An initial analytical screening considering factors such as trajectory accuracy, manufacturability, and hydrodynamics of orifice flow is presented. Based on this screening, four technologies were selected for experimental evaluation. A jet straightness system used to test 50-orifice arrays made by electro-discharge machining (EDM), Fotoceram, and mechanical drilling is discussed. Measurements on orifice diameter control and jet trajectory accuracy are presented and discussed. Trajectory standard deviations are in the 4.6-10.0 milliradian range. Electroforming and EDM appear to have the greatest potential for Liquid Droplet Radiator applications. The direction of a future development effort is discussed
Financing Georgia's Future
This report explores how Georgia finances its expenditures through various revenue sources and compares Georgia's taxes across states and over time on multiple dimensions
Distal occurrence of mid-Holocene Whakatane Tephra on the Chatham Islands, New Zealand, and potential for cryptotephra studies
The Whakatane Tephra, a rhyolitic tephra erupted ca. 5500 cal. BP from Okataina Volcanic Centre, central North Island, has been identified on the Chatham Islands which lie Ë900 km east of Christchurch, New Zealand. The visible tephra layer, Ë5 mm in thickness and preserved within peat on Pitt Island, was identified using both radiocarbon dating and analysis of glass shards by electron microprobe. Whakatane Tephra is the first Holocene tephra to be identified on the Chatham Islands, and it is the most distal Holocene tephra yet recorded in the New Zealand region, being Ë850 km from source. The Pitt Island occurrence extends the tephra's dispersal area markedly, by an order of magnitude, possibly to Ë300,000 km2. An estimated dispersal index (D) of approximately 105 km2 indicates that the eruption generated a very high plinian column, possibly exceeding Ë30 km in height, with strong winds blowing the ash plume southeastwards. This new discovery of distal Whakatane Tephra as a thin but visible layer strongly implies that cryptotephras are likely to be preserved on the Chatham Islands and within adjacent ocean floor sediments. Therefore the potential exists to develop enhanced cryptotephrostratigraphic records from these distal areas, which in turn would help facilitate precise correlation via tephrochronology of palaeoenvironmental records (such as NZ-INTIMATE) from mainland New Zealand, the southwest Pacific Ocean, and the Chatham Islands
Excited state baryon spectroscopy from lattice QCD
We present a calculation of the Nucleon and Delta excited state spectrum on
dynamical anisotropic clover lattices. A method for operator construction is
introduced that allows for the reliable identification of the continuum spins
of baryon states, overcoming the reduced symmetry of the cubic lattice. Using
this method, we are able to determine a spectrum of single-particle states for
spins up to and including J = 7/2, of both parities, the first time this has
been achieved in a lattice calculation. We find a spectrum of states
identifiable as admixtures of SU(6) x O(3) representations and a counting of
levels that is consistent with the non-relativistic constituent quark
model. This dense spectrum is incompatible with quark-diquark model solutions
to the "missing resonance problem" and shows no signs of parity doubling of
states.Comment: 29 pages, 18 figure
Prevalence and predictors of postdischarge antibiotic use following mastectomy
OBJECTIVESurvey results suggest that prolonged administration of prophylactic antibiotics is common after mastectomy with reconstruction. We determined utilization, predictors, and outcomes of postdischarge prophylactic antibiotics after mastectomy with or without immediate breast reconstruction.DESIGNRetrospective cohort.PATIENTSCommercially insured women aged 18â64 years coded for mastectomy from January 2004 to December 2011 were included in the study. Women with a preexisting wound complication or septicemia were excluded.METHODSPredictors of prophylactic antibiotics within 5 days after discharge were identified in women with 1 year of prior insurance enrollment; relative risks (RR) were calculated using generalized estimating equations.RESULTSOverall, 12,501 mastectomy procedures were identified; immediate reconstruction was performed in 7,912 of these procedures (63.3%). Postdischarge prophylactic antibiotics were used in 4,439 procedures (56.1%) with immediate reconstruction and 1,053 procedures (22.9%) without immediate reconstruction (P<.001). The antibiotics most commonly prescribed were cephalosporins (75.1%) and fluoroquinolones (11.1%). Independent predictors of postdischarge antibiotics were implant reconstruction (RR, 2.41; 95% confidence interval [CI], 2.23â2.60), autologous reconstruction (RR, 2.17; 95% CI, 1.93â2.45), autologous reconstruction plus implant (RR, 2.11; 95% CI, 1.92â2.31), hypertension (RR, 1.05; 95% CI, 1.00â1.10), tobacco use (RR, 1.07; 95% CI, 1.01â1.14), surgery at an academic hospital (RR, 1.14; 95% CI, 1.07â1.21), and receipt of home health care (RR, 1.11; 95% CI, 1.04â1.18). Postdischarge prophylactic antibiotics were not associated with SSI after mastectomy with or without immediate reconstruction (bothP>.05).CONCLUSIONSProphylactic postdischarge antibiotics are commonly prescribed after mastectomy; immediate reconstruction is the strongest predictor. Stewardship efforts in this population to limit continuation of prophylactic antibiotics after discharge are needed to limit antimicrobial resistance.Infect Control Hosp Epidemiol2017;38:1048â1054</jats:sec
Visualising urban sustainability
Developing sustainable urban environments is complex and requires a number of factors â including social, economic and environmental sustainability - to be taken into account. This project is prototype software that produces a 3D virtual model of urban developments allowing viewers to see the short and long-term implications of courses of action
Financing an Increased State Role in Funding K-12 Education: An Analysis of Issues and Options
This report presents an analysis of replacing school property tax with alternative state revenue sources. FRC Report 11
Property Tax Assessment Quality: Willingness-to-Pay for Reduced Risk in a Lab Experiment*
We conduct a laboratory experiment to explore the willingness to pay to improve the accuracy of property assessment and issues regarding attitudes toward these assessments and taxes. We explore individual willingness to pay to improve property assessment accuracy; the extent to which the willingness to pay to improve the accuracy of property assessments depends on whether the risk for other property owners decreases; and fnally, we use the results to estimate demand for reduced risk and fnd that subjects were not willing to pay to reduce the assessment variance to a level consistent with best practices in property tax assessment
The Pacific Center of Action of the Northern Hemisphere Annular Mode: Real or Artifact?
The leading empirical orthogonal function (EOF) of the sea level pressure (SLP) field, referred to as the Arctic Oscillation (AO) or Northern Hemisphere annular mode (NAM), consists of a dipole between the polar cap region and the surrounding zonal ring centered along 458N. Embedded within the outer ring are centers of action over the Euro-Atlantic and Pacific sectors in which SLP fluctuates in phase. That the observed SLP fluctuations at these two centers of action are virtually uncorrelated raises the question of whether the Pacific center in the annular mode could be an artifact of EOF analysis. It is argued that sea level pressure fluctuations at the Pacific and Euro-Atlantic centers of action of the AO/ NAM would be more strongly correlated were it not for the fact that SLP variability over the North Pacific is dominated by a pattern in which fluctuations over the North Atlantic and North Pacific are inversely related. Evidence of the coexistence of such a pattern, which resembles an augmented version of the PacificâNorth American pattern, is presented
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