Sources and characteristics of interior noise in general aviation aircraft

A field study was conducted to examine the interior noise characteristics of a general aviation aircraft. The goals were to identify the major noise sources and their relative contribution and to establish the noise transmission paths and their relative importance. Tests were performed on an aircraft operating under stationary conditions on the ground. Results show that the interior noise level of light aircraft is dominated by broadband, low frequencies (below 1,000 Hz). Both the propeller and the engine are dominant sources, however, the contribution from the propeller is significantly more than the engine at its fundamental blade passage frequency. The data suggest that the airborne path is more dominant than the structure-borne path in the transmission of broadband, low frequency noise which apparently results from the exhaust

SOME IMPERATIVES OF THE GREEN REVOLUTION: TECHNICAL EFFICIENCY AND OWNERSHIP OF INPUTS IN INDIAN AGRICULTURE

This paper attempts to ascertain the requirements (in terms of ownership of factors of production) for successful adaptation to the Green Revolution in Indian agriculture. We estimate stochastic production frontiers for wheat in two Indian states: Haryana (which has been significantly affected by the Green Revolution) and Madhya Pradesh (where the Green Revolution has had much less effect). In Haryana, but not in Madhya Pradesh, larger farm size and ownership of land and machines positively influence technical efficiency. Thus, with the Green Revolution advancing, land consolidation and vesting of clear ownership rights of land and capital with farmers becomes important.Environmental Economics and Policy,

Testing the bus guardian unit of the FTMP

Fault-tolerant multiprocessor (FTMP) operation is discussed. Fault-modeling in the bus guardian units (BGUs) is covered. Testing the BGU is discussed. A testing algorithm is proposed

Optical Spectroscopy of Type Ia Supernovae

We present 432 low-dispersion optical spectra of 32 Type Ia supernovae (SNe Ia) that also have well-calibrated light curves. The coverage ranges from 6 epochs to 36 epochs of spectroscopy. Most of the data were obtained with the 1.5m Tillinghast telescope at the F. L. Whipple Observatory with typical wavelength coverage of 3700-7400A and a resolution of ~7A. The earliest spectra are thirteen days before B-band maximum; two-thirds of the SNe were observed before maximum brightness. Coverage for some SNe continues almost to the nebular phase. The consistency of the method of observation and the technique of reduction makes this an ideal data set for studying the spectroscopic diversity of SNe Ia.Comment: Accepted for publication in the Astronomical Journal, 109 pages (including data table), 44 figures, full resolution figures at http://www.noao.edu/noao/staff/matheson/Iaspec.ps.g

Tm3+/Ho3+ codoped tellurite fiber laser

Continuous-wave and Q-switched lasing from a Tm 3+ /Ho 3+ codoped tellurite fiber is reported. An Yb 3+ /Er 3+ -doped silica fiber laser operating at 1.6μm was used as an in-band pump source, exciting the Tm 3+ ions into the F 4 3 level. Energy is then nonradiatively transferred to the upper laser level, the I 7 5 state of Ho 3+ . The laser transition is from the I 7 5 level to the I 8 5 level, and the resulting emission is at 2.1μm . For continuous wave operation, the slope efficiency was 62% and the threshold 0.1W ; the maximum output demonstrated was 0.16W . Mechanical Q switching resulted in a pulse of 0.65μJ energy and 160ns duration at a repetition rate of 19.4kHz

Distributed Ada: Methodology, notation and tools

The task of creating software to run on a distributed system brings with it many problems not encountered in a uni-processor environment. The designer, in addition to creating a solution to meet the functional requirements of the applicaiton, must determine how to distribute that functionality in order to meet the nonfunctional requirements such as performance and fault tolerance. In the traditional approach to building distributed software systems, decisions of how to partition the software must be made early in the design process so that a separate program can be written for each of the processors in the system. This design paradigm is extremely vulnerable to changes in the target hardware environment, as well as being sensitive to poor initial guesses about what distribution of functionality will satisfy the nonfunctional requirements. The paradigm is also weak in that no compiler has a complete view of the system. Many of the advantages of using a powerful language system are lost in a one-program-per-processor environment. Another approach to the development of distributed software systems, Honeywell's Distributed Ada program, is presented

Redressing racial inequities through water law in South Africa: revisiting old contradictions? Draft

Water lawCatchment areasRiver basinsSocial aspectsPovertyInstitutional development

A target for production of radioxenons

A liquid cesium target has been developed which allows the production and separate identification of the neutron deficient isotopes of xenon. The present report describes irradiations utilizing 34 to 41 MeV protons to produce millicurie quantities of Xe-127 and Xe-129m. At higher energies, however, the target could be used without modification to produce xenon isotopes as light as 119