Programs at Wright-patterson Air Force Base

The Lubrication Branch has two active programs that are developing gas turbine engine mainshaft air/oil seals. Both of these programs, one of which is with General Electric Aircraft Engines and the other with Pratt & Whitney Aircraft, are addressing counter-rotating intershaft applications which involve very high rubbing velocities. The objectives and requirements of these efforts are briefly addressed

Computer program for the design of toroidal transformers

Program relieves designer of most of the computational details, while he maintains control over most engineering decisions. Number of specifications that must be supplied by user allows for considerable flexibility and for exercise of engineering judgment. Speed of program makes it possible to run many cases, economically determining effect of various parameter changes

SUBSET: Best Subsets using Information Criteria

SUBSET, written in the matrix language Gauss, is a program that identifies optimal subsets of means or proportions based on independent groups. All possible configurations of ordered subsets of groups are identified and the best model is selected using either the AIC or BIC information criterion. For means, both homogeneous and heterogeneous variance cases are considered. SUBSET offers an alternative approach to traditional post-hoc multiple-comparison procedures such as the Tukey test for pairwise comparisons. Major advantages of SUBSET over traditional pairwise comparison procedures include the fact that intransitive decisions are avoided and that issues related to type I error control, sample size and heterogeneity of variance do not arise.

Design of a multistage depressed collector for the F-16 radar dual mode transmitter tube

The design of a multistage depressed collector (MDC) for use with the F-16 radar dual mode transmitter tube is described. The methods employed and the rationale on which the design is based are presented

System efficiency of a microwave power tube with a multistage depressed collector

The efficiencies of a microwave power tube with a multistage depressed collector and of the power supply driving the tube are computed. An analytical expression for the collector efficiency, which includes the effect of secondary emission and the radial component of velocity, is derived for a hypothetical current probability distribution function. In addition, collector efficiency is calculated with the aid of a digital computer for a specific current distribution. The efficiency of the power supply required to operate the tube in a space environment is estimated by using a simple parallel inverter system

Toroidal transformer design program with application to inverter circuitry

Estimates of temperature, weight, efficiency, regulation, and final dimensions are included in the output of the computer program for the design of transformers for use in the basic parallel inverter. The program, written in FORTRAN 4, selects a tape wound toroidal magnetic core and, taking temperature, materials, core geometry, skin depth, and ohmic losses into account, chooses the appropriate wire sizes and number of turns for the center tapped primary and single secondary coils. Using the program, 2- and 4-kilovolt-ampere transformers are designed for frequencies from 200 to 3200 Hz and the efficiency of a basic transistor inverter is estimated

Conservation Reserve Program Participation and Acreage Enrollment of Working Farms

Among Conservation Reserve Program (CRP) participants, there is a distinction between farm households using the program to ease out of farming and those using the program to augment production receipts. We find evidence that factors other than farm profitability and environmental factors may influence program participation of farmers who continue agricultural production. Program payments and farm size positively correlate with the amount of land enrolled in the CRP, and characteristics of participants in land retirement and working-lands CRP components are similar.Environmental Economics and Policy,

Observational and modeling studies of heat, moisture, precipitation, and global-scale circulation patterns

The research sponsored by this grant is a continuation and an extension of the work conducted under a previous contract, 'South Pacific Convergence Zone and Global-Scale Circulations'. In the prior work, we conducted a detailed investigation of the South Pacific convergence zone (SPCZ), and documented many of its significant features and characteristics. We also conducted studies of its interaction with global-scale circulation features through the use of both observational and modeling studies. The latter was accomplished toward the end of the contract when Dr. James Hurrell, then a Ph.D. candidate, successfully ported the NASA GLA general circulation model (GCM) to Purdue University. In our present grant, we have expanded our previous research to include studies of other convectively-driven circulation systems in the tropics besides the SPCZ. Furthermore, we have continued to examine the relationship between these convective systems and global-scale circulation patterns. Our recent research efforts have focused on three objectives: (1) determining the periodicity of large-scale bands of organized convection in the tropics, primarily synoptic to intraseasonal time scales in the Southern Hemisphere; (2) examining the relative importance of tropical versus mid-latitude forcing for Southern Hemisphere summertime subtropical jets, particularly over the Pacific Ocean; and (3) estimating tropical precipitation, especially over oceans, using observational and budget methods. A summary list of our most significant accomplishments in the past year is given

Short-run Birth and Death of U.S. Manufacturing Firms: 2000 - 2005

Attracting manufacturing investment remains a viable regional development policy. Previous research in the location literature has informed policymakers which factors are most important for attracting new firm investment. Far less is known about the dynamics of firm death and the possible interaction with firm birth. A conceptual model of county-level investment in the U.S. manufacturing sector is developed from location theory and subsequent literature. Specifically, we test the relative importance of location factors influencing firm investment, and if these factors influence firm birth and death differently. Local factors include labor quality, availability, and cost, market conditions, agglomeration due to localization and urbanization economies, infrastructure, and fiscal policy. This study covers the time period 2000 to 2004 for U.S. counties in the lower 48 states. Firm data are from the U.S. Census Bureau’s Dynamic Firm Data Series, which links establishments across space and time. Regional adjustment models are used to show how ceteris paribus changes in location factors affect the birth and death rates in a county.location factors, manufacturing, creative destruction, Community/Rural/Urban Development, L60, R11, R12,