33,126 research outputs found

    The economic value of remote sensing of earth resources from space: An ERTS overview and the value of continuity of service. Volume 4: Forestry, wildlife and rangeland

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    The economic value of ERS information in the resource management area of extensive use of living resources, forestry, wildlife, and rangeland, is determined. Timber and forage resources are quantitatively evaluated. It is shown that these resources have economic value in the tens of billions of dollars, but the economic benefits of improved management of the forests and rangelands are not limited to efficiency in the production of these commercial resources. Multiple-use values including watershed, wildlife, and recreation are also involved

    Inverter ratio failure detector

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    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship

    Effects of an on line bypass oil recycler on emissions with oil age for a bus using in service testing

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    A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infra red heater. Two bypass filter sizes of 6 and 1 micron were investigated, both filter sizes were effective but the one micron filter had the greatest benefit. This was tested on two nominally identical EURO 2 emissions compliance single decker buses, fitted with Cummins 6 cylinder 8.3 litre turbocharged intercooled engines and coded as Bus 4063 and 4070. These vehicles had emissions characteristics that were significantly different, in spite of their similar age and total mileage. Bus 4063 showed an apparent deterioration on emissions with time while Bus 4070 showed a stabilised trend on emissions with time for their baseline tests without the recycler fitted. Comparison was made with the emissions on the same vehicles and engines with and without the on-line bypass oil recycler. Engine exhaust emissions were measured about every 2000 miles. All tests started with an oil drain and fresh lubricating oil. The two buses were tested in a different sequence, Bus 4063 with the recycler fitted and then removed later in the test after an oil change and Bus 4070 with no recycler fitted at first and then fitted after 29,000 miles with no oil change. The Bus 4070 was also the one with the finer bypass filter. The test mileage was 45,000 miles for Bus 4063 and 48,000 miles for Bus 4070. The air/fuel ratio was worked out by the exhaust gas analysis. The correlation between air/fuel ratio and emission parameters was determined. The results showed that the on line oil recycler cleaning system reduced the rate of increase of the NOx from 5% to 1.6% for Bus 4063 and from 4.1% to 0% for Bus 4070 per 10,000 miles. Hydrocarbon emissions increased 30 ppm per 10,000 miles with the recycler removed compared to a stabilised level with the recycler fitted for Bus 4063. There was a small decrease in hydrocarbon emissions after fitting the recycler for Bus 4070. The particulate emissions were reduced by 35% for Bus 4063 and 24% for Bus 4070 on average. The reductions on total particulate mass were due to reductions on particulate carbon and lube oil VOF emissions. The black smoke was reduced by 56% for Bus 4063 in terms of rate of increase and 40% for Bus 4070 in terms of average value

    The influence of an oil recycler on emissions with oil age for a refuse truck using in service testing

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    A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infra red heater. Two bypass filter sizes of 6 and 1 micron were investigated, both filter sizes were effective but the one micron filter had the greatest benefit. This was tested on two nominally identical EURO 1 emissions compliance refuse trucks, fitted with Perkins Phazer 210Ti 6 litre turbocharged intercooled engines and coded as RT320 and RT321. These vehicles had emissions characteristics that were significantly different, in spite of their similar age and total mileage. RT321 showed an apparent heavier black smoke than RT320. Comparison was made with the emissions on the same vehicles and engines with and without the on-line bypass oil recycler. Engine exhaust emissions were measured about every 400 miles. Both vehicles started the test with an oil drain and fresh lubricating oil. The two refuse trucks were tested in a different sequence, the RT320 without the recycler fitted and then fitted later and the RT321 with the recycler fitted and then removed later in the test and both without any oil change. The RT320 was also the one with the finer bypass filter. The test mileage was nearly 8,000 miles both trucks. The air/fuel ratio was worked out by the exhaust gas analysis. The correlation between air/fuel ratio and emission parameters was determined and appropriate corrections were made in the case of that the air/fuel ratio had an effect on emissions. The results showed that the on line oil recycler cleaning system can reduce the rate of increase of the NOx with oil age. There appeared little influence of the oil recycler on carbon monoxide and hydrocarbon emissions. The rate of increase in particulate emissions was reduced by 50% for RT320 and an immediate decrease in particulate emissions was seen on RT320 test after fitting the recycler. The black smoke was reduced by 30% for RT320 in terms average value and an immediate decrease in smoke after fitting the recycler on RT320 test and an immediate increase in smoke after the removal of the recycler on RT321 test were shown

    Fermionic characters for graded parafermions

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    Fermionic-type character formulae are presented for charged irreduciblemodules of the graded parafermionic conformal field theory associated to the coset osp(1,2)k/u(1)osp(1,2)_k/u(1). This is obtained by counting the weakly ordered `partitions' subject to the graded ZkZ_k exclusion principle. The bosonic form of the characters is also presented.Comment: 24 p. This corrects typos (present even in the published version) in eqs (4.4), (5.23), (5.24) and (C.4

    The Dust Properties of Eight Debris Disk Candidates as Determined by Submillimeter Photometry

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    The nature of far-infrared dust emission toward main sequence stars, whether interstellar or circumstellar, can be deduced from submillimeter photometry. We present JCMT/SCUBA flux measurements at 850 microns toward 8 stars with large photospheric excesses at 60-100 microns. 5 sources were detected at 3-sigma or greater significance and one was marginally detected at 2.5-sigma. The inferred dust masses and temperatures range from 0.033 to 0.24 Earth masses and 43-65 K respectively. The frequency behavior of the opacity, tau_nu ~ nu^beta, is relatively shallow, beta < 1. These dust properties are characteristic of circumstellar material, most likely the debris from planetesimal collisions. The 2 non-detections have lower temperatures, 35-38 K and steeper opacity indices, beta > 1.5, that are more typical of interstellar cirrus. The confirmed disks all have inferred diameters > 2'', most lie near the upper envelope of the debris disk mass distribution, and 4 are bright enough to be feasible for high resolution imaging.Comment: accepted by Ap
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