Instrument for determining coincidence and elapse time between independent sources of random sequential events

An instrument that receives pulses from a primary external source and one or more secondary external sources and determines when there is coincidence between the primary and one of the secondary sources is described. The instrument generates a finite time window (coincidence aperture) during which coincidence is defined to have occurred. The time intervals between coincidence apertures in which coincidences occur are measured

Thermal control of space vehicles Patent

Passive thermal control coating on aluminum foil laminate for inflatable spacecraft surface

The Growing Allocative Inefficiency of the U.S. Higher Education Sector

This paper presents new evidence on research and teaching productivity in universities using a panel of 102 top U.S. schools during 1981-1999. Faculty employment grows at 0.6 percent per year, compared with growth of 4.9 percent in industrial researchers. Productivity growth per researcher is 1.4-6.7 percent and is higher in private universities. Productivity growth per teacher is 0.8-1.1 percent and is higher in public universities. Growth in research productivity within universities exceeds overall growth, because the research share grows in universities where productivity growth is less. This finding suggests that allocative efficiency of U.S. higher education declined during the late 20th century. R&D stock, endowment, and post-docs increase research productivity in universities, the effect of nonfederal R&D is less, and the returns to research are diminishing. Since the nonfederal R&D share grows and is higher in public schools, this may explain the rising inefficiency. Decreasing returns in research but not teaching suggest that most differences in university size are due to teaching.

A computer program to generate equations of motion matrices, L217 (EOM). Volume 1: Engineering and usage

The equations of motion program L217 formulates the matrix coefficients for a set of second order linear differential equations that describe the motion of an airplane relative to its level equilibrium flight condition. Aerodynamic data from FLEXSTAB or Doublet Lattice (L216) programs can be used to derive the equations for quasi-steady or full unsteady aerodynamics. The data manipulation and the matrix coefficient formulation are described

The Growing Allocative Inefficiency of the U.S. Higher Education Sector

This paper presents new evidence on research and teaching productivity in universities. The findings are based on a panel that covers 1981-1999 and includes 102 top U.S. universities. Faculty size grows at 0.6 percent per year, compared with growth of 4.9 percent in the industrial science and engineering workforce. Measured by papers and citations per researcher, productivity grows at 1.4-6.7 percent per year and productivity and its rate of growth are higher in private than public universities. Measured by baccalaureate and graduate degrees per teacher, teaching productivity grows at 0.8-1.1 percent per year and growth is faster in public than private universities. A decomposition analysis shows that growth in research productivity within universities exceeds overall growth. This is because research shares grow more rapidly in universities whose productivity grows less rapidly. Likewise the research share of public universities increases even though productivity grows less rapidly in public universities. Together these findings suggest that allocative efficiency of U.S. higher education declined during the late 20th century. Regression analysis of individual universities finds that R&D stock, endowment, and postdoctoral students increase research productivity, that the effect of nonfederal R&D stock is less, and that research is subject to decreasing returns. Since the nonfederal R&D share grows and is much higher in public universities, this could account for some of the rising allocative inefficiency. The evidence for decreasing returns in research, which are greater than in teaching, suggests limits on the ability of more efficient institutions to expand and implies that differences in the scale of the teaching function are the primary reason for differences in university size. Besides all this the data strongly hint at growing financial pressures on U.S. public universities.

Science and Industry: Tracing the Flow of Basic Research through Manufacturing and Trade

This paper describes flows of basic research through the U.S. economy and explores their implications for scientific output at the industry and field level. The time period is the late 20th century. This paper differs from others in its use of measures of science rather than technology. Together its results provide a more complete picture of the structure of basic research flows than was previously available. Basic research flows are high within petrochemicals and drugs and within a second cluster composed of software and communications. Flows of chemistry, physics, and engineering are common throughout industry; biology and medicine are almost confined to petrochemicals and drugs, and computer science is nearly as limited to software and communications. In general, basic research flows are more concentrated within scientific fields than within industries. The paper also compares effects of different types of basic research on scientific output. The main finding is that the academic spillover effect significantly exceeds that of industrial spillovers or industry basic research. Finally, within field effects exceed between field effects, while the within- and between industry effects are equal. Therefore, scientific fields limit basic research flows more than industries.

Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors, part 8

An experimental investigation was conducted with an 0.8 hub/tip ratio, single-stage, axial flow compressor to determine the potential of tandem-airfoil blading for improving the efficiency and stable operating range of compressor stages. The investigation included testing of a baseline stage with single-airfoil blading and two tandem-blade stages. The overall performance of the baseline stage and the tandem-blade stage with a 20-80% loading split was considerably below the design prediction. The other tandem-blade stage, which had a rotor with a 50-50% loading split, came within 4.5% of the design pressure rise (delta P(bar)/P(bar) sub 1) and matched the design stage efficiency. The baseline stage with single-airfoil blading, which was designed to account for the actual rotor inlet velocity profile and the effects of axial velocity ratio and secondary flow, achieved the design predicted performance. The corresponding tandem-blade stage (50-50% loading split in both blade rows) slightly exceeded the design pressure rise but was 1.5 percentage points low in efficiency. The tandem rotors tested during both phases demonstrated higher pressure rise and efficiency than the corresponding single-airfoil rotor, with identical inlet and exit airfoil angles

A computer program to generate equations of motion matrices, L217 (EOM). Volume 2: Supplemental system design and maintenance document

The equations of motion program L217 (EOM) is described. The program formulates the matrix coefficients for a second order linear differential equation which describes the motion of an airplane relative to its level equilibrium flight condition. Aerodynamic data from FLEXSTAB or Doublet Lattice (L216) programs are used to derive the equations for quasi-steady or complete unsteady aerodynamics

Frequency domain laser velocimeter signal processor: A new signal processing scheme

A new scheme for processing signals from laser velocimeter systems is described. The technique utilizes the capabilities of advanced digital electronics to yield a smart instrument that is able to configure itself, based on the characteristics of the input signals, for optimum measurement accuracy. The signal processor is composed of a high-speed 2-bit transient recorder for signal capture and a combination of adaptive digital filters with energy and/or zero crossing detection signal processing. The system is designed to accept signals with frequencies up to 100 MHz with standard deviations up to 20 percent of the average signal frequency. Results from comparative simulation studies indicate measurement accuracies 2.5 times better than with a high-speed burst counter, from signals with as few as 150 photons per burst