Profile of Hired Farmworkers, 1996 Annual Averages

Examines demographic and employment characteristics of the 906,000 persons 15 years of age and older who did hired farmwork in 1996. Approximately 906,000 persons 15 years of age and older were employed as hired farmworkers each week in 1996. An additional 72,000 persons were hired as farmworkers each week as a secondary job. Hired farmworkers were more likely than all U.S. wage and salary workers to be male, Hispanic, younger, less educated, never married, and non-U.S. citizens.hired farmworkers, annual averages, demographic characteristics, hourse worked, median weekly hours, Labor and Human Capital,

A study of the absorption coefficient of silicon in the wave length region between .5 and 1.1 microns Final report

Solar cell performance prediction from absorption coefficients of silicon in wavelengths from 0.5 to 1 micron as functions of doping levels and crystal damag

Lifting surface theory for a helicopter rotor in forward flight

A lifting surface theory was developed for a helicopter rotor in forward flight for compressible and incompressible flow. The method utilizes the concept of the linearized acceleration potential and makes use of the vortex lattice procedure. Calculations demonstrating the application of the method are given in terms of the lift distribution on a single rotor, a two-bladed rotor, and a rotor with swept-forward and swept-back tips. In addition, the lift on a rotor which is vibrating in a pitching mode at 4/rev is given. Compressibility effects and interference effects for a two-bladed rotor are discussed

Lifting surface theory for a helicopter rotor in forward flight

A lifting surface theory has been developed for a helicopter rotor in forward flight for incompressible flow. The method utilized the concept of the linearized acceleration potential and make use of the vortex lattice procedures. Results in terms of lift coefficient slope for several forward flight conditions are given

Wind tunnel test results of a new leading edge flap design for highly swept wings, a vortex flap

A leading edge flap design for highly swept wings, called a vortex flap, was tested on an arrow wing model in a low speed wind tunnel. A vortex flap differs from a conventional plain flap in that it has a leading edge tab which is counterdeflected from the main portion of the flap. This results in intentional separation at the flap leading edge, causing a vortex to form and lie on the flap. By trapping this vortex, the vortex flap can result in significantly improved wing flow characteristics relative to conventional flaps at moderate to high angles of attack, as demonstrated by the flow visualization results of this tests

Moving Upstream to Prevent Child Maltreatment

Invited Commentary on Child Maltreatment Prevention - Finding Common Ground with Unintentional Injury Prevention

A Relationship of Trust: Are State ?School Trust Lands? Being Prudently Managed for the Beneficiary?

Every state entering the Union in the United States since 1803 received land grants from the federal government for the support of their public schools. Inherent in this federal grant is the fiduciary duty to prudently and effectively manage trust assets for the beneficiary, their school systems. This paper addresses the question of whether managers of trust lands are meeting their fiduciary responsibilities of ??maximum economic benefit?? for their beneficiaries. Realized market value-based economic returns from grazing lease revenues and capital appreciation for all twenty-three counties in Wyoming are compared with returns that may have been generated from alternative investment policy alternatives. Market values and capital appreciation for school trust lands in Wyoming are estimated from hedonic models formulated from ranch sales data and grazing revenue data.

Lewis icing research tunnel test of the aerodynamic effects of aircraft ground deicing/anti-icing fluids

A wind tunnel investigation of the effect of aircraft ground deicing/anti-icing fluids on the aerodynamic characteristics of a Boeing 737-200ADV airplane was conducted. The test was carried out in the NASA Lewis Icing Research Tunnel. Fluids tested include a Newtonian deicing fluid, three non-Newtonian anti-icing fluids commercially available during or before 1988, and eight new experimental non-Newtonian fluids developed by four fluid manufacturers. The results show that fluids remain on the wind after liftoff and cause a measurable lift loss and drag increase. These effects are dependent on the high-lift configuration and on the temperature. For a configuration with a high-lift leading-edge device, the fluid effect is largest at the maximum lift condition. The fluid aerodynamic effects are related to the magnitude of the fluid surface roughness, particularly in the first 30 percent chord. The experimental fluids show a significant reduction in aerodynamic effects

F-111 natural laminar flow glove flight test data analysis and boundary layer stability analysis

An analysis of 34 selected flight test data cases from a NASA flight program incorporating a natural laminar flow airfoil into partial wing gloves on the F-111 TACT airplane is given. This analysis determined the measured location of transition from laminar to turbulent flow. The report also contains the results of a boundary layer stability analysis of 25 of the selected cases in which the crossflow (C-F) and Tollmien-Schlichting (T-S) disturbance amplification factors are correlated with the measured transition location. The chord Reynolds numbers for these cases ranges from about 23 million to 29 million, the Mach numbers ranged from 0.80 to 0.85, and the glove leading-edge sweep angles ranged from 9 deg to 25 deg. Results indicate that the maximum extent of laminar flow varies from 56% chord to 9-deg sweep on the upper surface, and from 51% chord at 16-deg sweep to 6% chord at 25-deg sweep on the lower. The results of the boundary layer stability analysis indicate that when both C-F and T-S disturbances are amplified, an interaction takes place which reduces the maximum amplification factor of either type of disturbance that can be tolerated without causing transition

FOOD DISTRIBUTION RESEARCH PRIORITIES TO ALLOW MAJOR IMPROVEMENTS IN TOTAL SYSTEMS PRODUCTIVITY BY 1985: FOOD WHOLESALING

Agricultural and Food Policy,