Experimental investigation and analysis of two sources of nozzle-thrust misalignment

Asymmetry of nozzle's throat produces oscillatory type net side-force axial profile. Using mean values of localized static pressure and Mach number, scaling laws for flat-plate supersonic flow over protrusion are applied to nozzle expansion cone irregularities to give approximate indication of perturbed-pressure profiles and induced side forces

Cold-flow experimental investigation and analysis of two sources of nozzle thrust misalignment

Cold flow investigation and analysis of two nozzle thrust misalignmen

Solid propellant rocket motor

The characteristics of a solid propellant rocket engine with a controlled rate of thrust buildup to a desired thrust level are discussed. The engine uses a regressive burning controlled flow solid propellant igniter and a progressive burning main solid propellant charge. The igniter is capable of operating in a vacuum and sustains the burning of the propellant below its normal combustion limit until the burning propellant surface and combustion chamber pressure have increased sufficiently to provide a stable chamber pressure

Pulsed Generic Advertising: The Case of Common Property

Regulation of fisheries production together with public promotion of fisheries products offer a potentially profitable environment for fishermen. Yet production restrictions are usually insufficient to prevent entry, causing depletion of the resource base and dissipation of long-run profits from promotion. Shorter run gains may be possible, providing producer response to advertising is not instantaneous. Lagged biological and economic responses appear to provide a rationale for pulsed advertising. Moreover, a pulsed advertising policy is shown to mitigate the adverse effects on the resource base which would normally accompany expansion of consumption without direct production control.generic promotion, oysters, common property, pulsed advertising, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Differences in Iowa farms and their significance in the planning of agricultural programs

This bulletin reports the results of a study designed to measure the variations in cropping and livestock systems within the type·of-farming areas of Iowa. The national agricultural adjustment programs of recent years have recognized the variations between types of farming in different regions. The differences between farming systems within regions have received only limited recognition. Some of the shortcomings of the current agricultural programs have been attributed to their failure to make adequate allowance for individual farm variations

Changes in Student Behaviors and Policy Opinion Regarding E-Cigarettes at a Kentucky University from 2014 to 2018

The behaviors and opinions regarding e-cigarette use and campus policies prohibiting vaping vary greatly among college students nationally. Kentucky is one of the four U.S. states with the highest tobacco use prevalence, and characterizing e-cigarette use, trends and policy opinions among Kentucky undergraduates may inform interventions. To characterize population-level differences in e-cigarette-related behaviors and policy opinions among undergraduates from 2014 to 2018, results from two cross-sectional surveys (2014 and 2018) from a public regional university in south-central Kentucky were analyzed. Students from randomly selected undergraduate general studies courses completed a 5-minute in-class survey. Data were obtained from 514 and 519 respondents in 2014 and 2018, respectively. Mean age did not differ (19.9 and 20.1 years; p = 0.41) nor did class rank (p = 0.30) by survey year. Chi-square analysis indicated previous 30-day e-cigarette use was higher in 2018 than 2014 (28% vs. 18%; p \u3c 0.001), and current cigarette use was lower in 2018 than 2014 (13% vs. 25%; p \u3c 0.001). When current smoking and recent e-cigarette use were combined as a use variable, there was no significant difference between 2018 (29%) and 2014 (30%). Fraternity/sorority affiliation, being under 22 years old, male gender, out-of-state residency, and having a smoking parent were associated with recent e-cigarette use in multivariable logit models. Support for the on-campus vaping prohibition was lower among 2018 respondents (68% approval) compared to 2014 respondents (74% approval), respectively (p = 0.022). Overall, these findings may inform policy, population-specific health communications, and future research

Role of Perturbing Ocean Initial Condition in Simulated Regional Sea Level Change

Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm for the first 15 years of the 21st century. Regionally the sea level rise is not uniform due in large part to internal climate variability. To better serve the community, the uncertainties of predicting/projecting regional sea level changes associated with internal climate variability need to be quantified. Previous research on this topic has used single-model large ensembles with perturbed atmospheric initial conditions (ICs). Here we compare uncertainties associated with perturbing ICs in just the atmosphere and just the ocean using a state-of-the-art coupled climate model. We find that by perturbing the oceanic ICs, the uncertainties in regional sea level changes increase compared to those with perturbed atmospheric ICs. Thus, in order for us to better assess the full spectrum of the impacts of such internal climate variability on regional and global sea level rise, approaches that involve perturbing both atmospheric and oceanic initial conditions are necessary