Experimental measurement of the dynamic pressure distribution in a squeeze film bearing damper executing circular centered orbits

A review of previous experimental measurements of squeeze film damper (SFD) forces is given. Measurements by the authors of SFD pressure fields and force coefficients, for circular centered orbits with epsilon = 0.5, are described and compared with computer predictions. For Reynolds numbers over the range 2-6, the effect of fluid inertia on the pressure fields and forces is found to be significant

Effects of fluid inertia and turbulence on force coefficients for squeeze film dampers

The effects of fluid inertia and turbulence on the force coefficients of squeeze film dampers are investigated analytically. Both the convective and the temporal terms are included in the analysis of inertia effects. The analysis of turbulence is based on friction coefficients currently found in the literature for Poiseuille flow. The effect of fluid inertia on the magnitude of the radial direct inertia coefficient (i.e., to produce an apparent added mass at small eccentricity ratios, due to the temporal terms) is found to be completely reversed at large eccentricity ratios. The reversal is due entirely to the inclusion of the convective inertia terms in the analysis. Turbulence is found to produce a large effect on the direct damping coefficient at high eccentricity ratios. For the long or sealed squeeze film damper at high eccentricity ratios, the damping prediction with turbulence included is an order of magnitude higher than the laminar solution

A study examining the effectiveness of teaching reading using a literature-based approach vs. a basal approach

The purpose of this study was to determine if first grade students who were instructed following a literature based program would demonstrate a better understanding of reading. A comparison was made between the test scores and attitudes of those first grade students using a literature based reading program and those first grade students using a basal program. The design for this study was a pretest posttest design with one treatment group and one control group, both having 24 students. Both groups were pretested and posttested using the Scott, Foresman Celebrate Reading (1993), Anthology Assessment. This test was selected to measure student performance in the areas of phonics, word recognition, and comprehension in reading. The Paul Campbell Reading Attitude Inventory was also administered to see if there were any differences in the area of attitude. Data was statistically analyzed to determine if a significant difference was present. The study concluded that there was a significant difference in scores between the two groups, in terms of growth, on the Scott, Foresman Anthology Assessment as the literature based group performed significantly better; therefore, Hypothesis 1 was rejected. On the Paul Campbell Reading Inventory, there was no significant difference in scores leading to the acceptance of Hypothesis 2

Natural Infrastructure Alternatives Mitigate Hurricane-Driven Flood Vulnerability: Application to Tyndall Air Force Base

Hurricane frequency and magnitude intensification are expected over the remainder of the twenty-first century. Uncertainty in future projections requires that coastal communities approach adaptation decisions with caution. Traditional approaches are costly and inflexible. Soft policy adaptations are largely unenforceable. Hard, natural adaptations have emerged as an opportunity to partially mitigate the growing risk of extreme flooding, without the large investments required for traditional approaches, where natural infrastructure already exists. Existing literature for natural adaptations has not leveraged intensification expectations for hurricane events. This research uses multihazard damage evaluation software and spatial analysis to investigate placement of dredged sediment as a barrier island maintenance technique to determine economic viability, as compared to no-action alternatives. The efficacy of this strategy is tested against 18 threat and time calibrated scenarios, applied to existing barrier islands at Tyndall AFB. The results illustrate that protection of 7 square miles of existing barrier islands could help avert facility and infrastructure damage from high-intensity hurricane surge events predicted at 2100 by up to 3 orders of magnitude compared to a status quo scenario. The broader implications suggest that planners should look to preserve natural infrastructure that provides surge protection based on the ability to mitigate damages from intensified climate factors

Using Poultry Litter Ash as a Fertilizer Source for Bermudagrass (Cynodon dactylon) Establishment and Loblolly Pine (Pinus taeda) Plantation

Lower solubility of P in poultry litter ash (PLA) than conventional phosphorus (P) fertilizers such as triple superphosphate (TSP) may reduce P losses in drainage and runoff; however, lower P solubility may reduce its efficacy as a P source. A laboratory experiment was conducted to examine the effect of acidity on P release and the effect of different combustion temperatures on P solubility as a prerequisite to the following studies. The first research objective was to determine the effect of soil pH on the efficiency of PLA relative to TSP for establishment of common bermudagrass (Cynodon dactylon L.) and P loss on representative coastal plain soil and. In the study, yields and tissue concentrations were greater where fertilized. Yields were minimally greater with TSP but there were no consistent differences in tissue concentrations between PLA and TSP. Leaching of P was negligible regardless of P fertilizer solubility, however, P runoff losses significantly decreased TSP\u3ePLA\u3econtrol. The second research objective was to evaluate PLA compared to triple superphosphate in ratios of PLA:TSP of 0:100, 25:75; 50:50; 75:100 as a pre-plant fertilizer incorporated into a 90:10 (v/v) sand and peat mixture seeded with bermudagrass. Compared to TSP, PLA reduced P, K, Ca, and Mg leaching losses during the first two weeks after planting. As the percentage of PLA increased relative to TSP, nutrient leaching decreased incrementally. The objective of the third study was to determine whether P supplied as PLA produced an effect equal to that of TSP on loblolly pine (Pinus taeda L.) growth and nutrient uptake at mid-rotation of two genotypes (eastern and western) on a coastal plain soil. Effects on soil parameters and runoff P were also examined. Through 2+ years, P fertilization and source had no effect on tree growth, but foliar P concentrations were greatest with TSP, and short-term increase in stem diameter was greater for the eastern genotype. There was numerically less P in runoff with PLA than TSP, however, variability among replicates precluded significance. Based on the data from these studies, PLA has the potential to reduce P loss and serve as an alternative to conventional P fertilizers

Discussant\u27s response to setting standards for statistical sampling in auditing

https://egrove.olemiss.edu/dl_proceedings/1070/thumbnail.jp

BIOMASS FOR ELECTRICITY AND PROCESS HEAT AT ETHANOL PLANTS

Published in: Applied Engineering in Agriculture, Vol. 22(5): 723-728Biomass, Process heat, Ethanol production, Electricity, Combined heat and power, Resource /Energy Economics and Policy,

Implicit Bayesian Inference Using Option Prices

A Bayesian approach to option pricing is presented, in which posterior inference about the underlying returns process is conducted implicitly via observed option prices. A range of models allowing for conditional leptokurtosis, skewness and time-varying volatility in returns are considered, with posterior parameter distributions and model probabilities backed out from the option prices. Models are ranked according to several criteria, including out-of-sample fit, predictive and hedging performance. The methodology accommodates heteroscedasticity and autocorrelation in the option pricing errors, as well as regime shifts across contract groups. The method is applied to intraday option price data on the S&P500 stock index for 1995. Whilst the results provide support for models which accommodate leptokurtosis, no one model dominates according to all criteria considered.Bayesian Option Pricing; Leptokurtosis; Skewness; GARCH Option Pricing; Option Price Prediction; Hedging Errors.