Thermopile vacuum gage tube simulator Patent

Simulating operation of thermopile vacuum gage tube at high and low pressure

Noise figure measurement concept for acoustic amplifiers

Optimum length buffer crystals are used with an amplification section for measuring the noise figure for acoustic amplifiers. Measuring the time required to saturate with noise a signal, which is reflected back and forth in the circuit, gives a direct measurement of the amplifiers noise figure

Aeroelastic considerations for torsionally soft rotors

A research study was initiated to systematically determine the impact of selected blade tip geometric parameters on conformable rotor performance and loads characteristics. The model articulated rotors included baseline and torsionally soft blades with interchangeable tips. Seven blade tip designs were evaluated on the baseline rotor and six tip designs were tested on the torsionally soft blades. The designs incorporated a systemmatic variation in geometric parameters including sweep, taper, and anhedral. The rotors were evaluated in the NASA Langley Transonic Dynamics Tunnel at several advance ratios, lift and propulsive force values, and tip Mach numbers. A track sensitivity study was also conducted at several advance ratios for both rotors. Based on the test results, tip parameter variations generated significant rotor performance and loads differences for both baseline and torsionally soft blades

Productivity Divergence across Kansas Farms

This study used 30 years of continuous data for 135 farms in Kansas to explore changes in productivity using Malmquist productivity indices (MPI). The indices were used to determine whether there was productivity convergence or divergence in Kansas farms. The results showed there was significant divergence among the farms. The average annual productivity growth was 0.50 percent; the top farms based on MPI were larger in terms of value of farm production, crop farm income, and livestock farm income and received a larger percentage of their income from oilseeds, feed grains, and swine than the other farms on average.convergence, divergence, productivity growth, Production Economics, Productivity Analysis,

Wind-tunnel investigation of the effects of blade tip geometry on the interaction of torsional loads and performance for an articulated helicopter rotor

The Langley transonic dynamics tunnel was used to determine the degree of correlation between rotor performance and the dynamic twist generated by changes in blade tip geometry using an articulated rotor with four different tip geometries at advance ratios of 0.20, 0.30 and 0.35. Based on the data obtained, it is concluded that: (1) there appears to be no strong correlation between blade torsion loads and rotor performance prediction; (2) for a given rotor task at each advance ratio investigated, both the azimuthal variation of torsional moment and the mean torsional moment at 81% radius are configuration dependent; (3) reducing the nose down twist on the advancing blade appears to be more important to forward flight performance than increasing the nose down twist on the retreating blade; (4) the rotor inflow model used was important in predicting the performance of the adaptive rotor; and (5) neither rigid blade solidity effects, inflow environment, nor blade torsion loads can be used alone to accurately predict active rotor performance

Productivity Divergence Across Kansas Farms

This study used 30 years of continuous data for 135 farms in Kansas to explore changes in productivity using Malmquist productivity indices. The indices were used to determine whether there was productivity convergence or divergence in Kansas farms. The results showed that there was significant divergence among the farms and not a tendency for farms to catch-up to the same levels of productivity as the top farms in the sample. The average annual productivity growth over the sample period, 1979-2008, was 0.50 percent. The top farms based on MPI were larger in terms of value of farm production, crop farm income and livestock farm income and received a larger percentage of their income from oilseeds, feed grains, and swine than the other farms on average and relatively less of their income from small grains.Farm Management, Production Economics, Productivity Analysis,

Fast scan control for deflection type mass spectrometers

A high speed scan device is reported that allows most any scanning sector mass spectrometer to measure preselected gases at a very high sampling rate. The device generates a rapidly changing staircase output which is applied to the accelerator of the spectrometer and it also generates defocusing pulses that are applied to one of the deflecting plates of the spectrometer which when shorted to ground deflects the ion beam away from the collector. A defocusing pulse occurs each time there is a change in the staircase output

Correlation of full-scale helicopter rotor performance in air with model-scale Freon data

An investigation was conducted in a transonic dynamics tunnel to measure the performance of a 1/5 scale model helicopter rotor in a Freon atmosphere. Comparisons were made between these data and full scale data obtained in air. Both the model and full scale tests were conducted at advance ratios between 0.30 and 0.40 and advancing tip Mach numbers between 0.79 and 0.95. Results show that correlation of model scale rotor performance data obtained in Freon with full scale rotor performance data in air is good with regard to data trends. Mach number effects were found to be essentially the same for the model rotor performance data obtained in Freon and the full scale rotor performance data obtained in air. It was determined that Reynolds number effects may be of the same magnitude or smaller than rotor solidity effects or blade elastic modeling in rotor aerodynamic performance testing

Parametric tip effects for conformable rotor applications

A research study was initiated to systematically determine the impact of selected blade tip geometric parameters on aeroelasticity conformable rotor performance and loads characteristics. The model articulated rotors included baseline and torsionally soft blades with interchangeable tips. Seven blade tip designs were evaluated on the baseline rotor and three tip designs were tested on the torsionally soft blades. The designs incorporated a systematic variation in three geometric parameters: sweep, taper, and anhedral. The rotors were evaluated in the NASA Langley Transonic Dynamics Tunnel at several advance ratios, lift and propulsive force values, and tip Mach numbers. Based on the test results, tip parameter variations generated significant rotor performance and loads difference for both baseline and torsionally soft blades. Azimuthal variation of elastic twist generated by the tip parameters strongly correlated with rotor performance and loads, but the magnitude of advancing blade elastic twist did not correlate

Scale economies and geographic diversification as forces driving community bank mergers

Mergers of community banks across economic market areas potentially reduce both idiosyncratic and local market risk. Idiosyncratic risk may be reduced because the larger post merger bank has a larger customer base. Negative credit and liquidity shocks from individual customers would have smaller effects on the portfolio of the merged entity than on the individual community banks involved in the merger. Geographic dispersion of banking activities across economic market areas may reduce local market risk because an adverse economic development that is unique to one market area will not affect a bank*s loans to customers in different market areas. This paper simulates the mergers of community banks both within and across economic market areas by combining their call report data. We find that the potential for idiosyncratic risk reduction dominates the marginal contribution to risk reduction by diversifying across local markets. In other words, a typical community bank can reduce its insolvency risk about as much by merging with a bank across the street as it can by merging with one located across the country. The bulk of the pure portfolio diversification effects for community banks, therefore, appears to be unrelated to diversification across market areas and instead is related to bank size. These findings may help explain why many community banks have not pursued geographic diversification more aggressively, but they beg the question as to why more small community banks do not pursue in-market mergers.Community banks ; Bank mergers