Fuel injector characterization studies

The atomization of several general aviation piston engine manifold port fuel injectors was investigated. The injectors were installed in a test rig and operated under simulated conditions. Laser interferometric techniques were used to optically probe the spray droplet fields for droplet size and velocity at numerous spatial locations throughout the field

Space shuttle: Static stability characteristics and control surface effectiveness of the Boeing .00435 scale model space shuttle booster H-32

Experimental aerodynamic investigations were made in the Grumman 36-inch hypersonic wind tunnel on a .00435 scale model of the H-32 reusable space shuttle booster. The objectives of the test were to determine the static stability characteristics and control surface effectiveness at hypersonic speeds. Data were taken at M = 8.12 over a range of angles of attack between -5 and 85 deg at beta = 0 deg and over a range of side slip angles between -10 and 10 deg at alpha = 0 and 70 deg. Six component balance data and base-cavity pressure data were recorded

Analysis and testing of a new method for drop size measurement using laser scatter interferometry

Research was conducted on a laser light scatter detection method for measuring the size and velocity of spherical particles. The method is based upon the measurement of the interference fringe pattern produced by spheres passing through the intersection of two laser beams. A theoretical analysis of the method was carried out using the geometrical optics theory. Experimental verification of the theory was obtained by using monodisperse droplet streams. Several optical configurations were tested to identify all of the parametric effects upon the size measurements. Both off-axis forward and backscatter light detection were utilized. Simulated spray environments and fuel spray nozzles were used in the evaluation of the method. The measurements of the monodisperse drops showed complete agreement with the theoretical predictions. The method was demonstrated to be independent of the beam intensity and extinction resulting from the surrounding drops. Signal processing concepts were considered and a method was selected for development

Taxes and the poor: A microsimulation study of implicit and explicit taxes

The authors measure the cumulative burden on low-income households resulting from explicit taxes (state and federal income, and payroll taxes) and implicit taxes (reductions of program benefits as earnings rise). With monthly data from the 1990 Survey of Income and Program Participation, a simulation model calculates the benefits and taxes households receive and pay in 1990. A household's marginal tax rate is established by simulating the benefits and taxes the household would receive and pay if each member aged 15 or more received additional earnings of $10 per month. The changes in income that would result if all household members age 15 or older took a half-time, minimum-wage job are also calculated. Typical cumulative marginal tax rates on poor households are found to be about 27 percent, but this masks considerable variation across states as a result of differences in program eligibility rules, state income taxes, and state AFDC policies. The tax burdens resulting from taking a half-time minimum-wage job also vary greatly across states, and participants in AFDC and food stamps face median marginal tax rates significantly above the rates for all poor households. A consistent result, however, is that typical tax rates on the poor rarely exceed 60 percent when income changes resulting from incremental changes in monthly earnings are calculated. The authors conclude that for most poor households, tax rates are not so high as to diminish the possible effectiveness of such policies as the Earned Income Tax Credit, which try to make work more attractive than welfare.

Space shuttle: Verification of transition reentry corridor at high angles of attack and determination of transition aerodynamic characteristics and subsonic aerodynamic characteristics at low angles of attack for the Boeing H-32 booster

Experimental aerodynamic investigations were made in a transonic wind tunnel on a 1/150-scale model of the Boeing H-32 space shuttle booster configuration. The purpose of the test was: (1) to verify the transonic reentry corridor at high angles of attack; (2) to determine the transonic aerodynamic characteristics; and (3) to determine the subsonic aerodynamic characteristics at low angles of attack. Test variables included configuration buildup, horizontal stabilizer settings of 0 and -20 deg, elevator deflections of 0 and -30 deg, and wing spoiler settings of 60 deg

Development and testing of a greenhouse assay for screening potato germplasm for susceptibility to Spongospora subterranea f. sp. subterranea (powdery scab)

2008 Summer.Covers not scanned.Includes bibliographical references.Potato resistance to powdery scab, caused by the protist Spongospora subterranea f. sp. subterranea (S.s.s.), has become extremely important in recent years due to the increased damage caused by this disease. Variable field conditions and the environmental sensitivity of the S.s.s. infection process in naturally infested fields have created difficulties in consistently evaluating potato germplasm resistance. A greenhouse assay for evaluating potato germplasm resistance which is consistent and compatible with field results was developed. Two soil types, three inoculum levels, two inoculum sources and two soil moisture regimes were evaluated in a greenhouse for powdery scab severity using four potato cultivars. Soil temperature was maintained at an ideal range for powdery scab development as reported in current literature. Greenhouse results were then compared with three years of fi eld data collected from field trials conducted in the San Luis Valley (SLV). Cultivars were evaluated for root galling, tuber lesion incidence, and severity. Soil with 50% sand, an inoculum level of one sporeball per gram of soil , and relatively high soil moisture (0-10 chars) had the most consistent symptom expression when compared with field results . This combination of factors was then tested m a greenhouse using fourteen potato cultivars which varied in levels of powdery scab susceptibility. A relative ranking system was also developed to compare greenhouse results with known SLY field results. Results demonstrated that a greenhouse assay can be used successfully for screening advanced potato germplasm for susceptibility to powdery scab