A low-NO x aircraft gas turbine engine combustion concept was developed and tested. The concept is a second generation swirl-venturi lean direct injection (SV-LDI) concept. LDI is a lean-burn combustion concept in which the fuel is injected directly into the flame zone. Three second generation SV-LDI configurations were developed. All three were based on the baseline 9-point SV-LDI configuration reported previously. 1 These second generation configurations had better low power operability than the baseline 9-point configuration. Two of these second generation configurations were tested in a NASA Glenn Research Center flametube; these two configurations are called the flat dome and 5-recess configurations. Results show that the 5-recess configuration generally had lower NO x emissions than the flat dome configuration. Correlation equations were developed for the flat dome configuration so that the landing-takeoff NO x emissions could be estimated. The flat dome landing-takeoff NO x is estimated to be 87-88% below the CAEP/6 standards, exceeding the ERA project goal of 75% reduction.

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PurposeTo estimate annual health care and productivity loss costs attributable to overweight or obesity in working asthmatic patients.Materials and MethodsThis study was conducted using the 2003–2013 Medical Expenditure Panel Survey (MEPS) in the United States. Patients aged 18 to 64 years with asthma were identified via self-reported diagnosis, a Clinical Classification Code of 128, or a ICD-9-CM code of 493.xx. All-cause health care costs were estimated using a generalized linear model with a log function and a gamma distribution. Productivity loss costs were estimated in relation to hourly wages and missed work days, and a two-part model was used to adjust for patients with zero costs. To estimate the costs attributable to overweight or obesity in asthma patients, costs were estimated by the recycled prediction method.ResultsAmong 11670 working patients with a diagnosis of asthma, 4428 (35.2%) were obese and 3761 (33.0%) were overweight. The health care costs attributable to obesity and overweight in working asthma patients were estimated to be $878 [95% confidence interval (CI): $861–$895] and $257 (95% CI: $251–$262) per person per year, respectively, from 2003 to 2013. The productivity loss costs attributable to obesity and overweight among working asthma patients were $256 (95% CI: $253–$260) and $26 (95% CI: $26–$27) per person per year, respectively.ConclusionHealth care and productivity loss costs attributable to overweight and obesity in asthma patients are substantial. This study's results highlight the importance of effective public health and educational initiatives targeted at reducing overweight and obesity among patients with asthma, which may help lower the economic burden of asthma.