A total life prediction model for stress concentration sites

Fatigue crack growth tests were performed on center crack panels and radial crack hole samples. The data were reduced and correlated with the elastic parameter K taking into account finite width and corner crack corrections. The anomalous behavior normally associated with short cracks was not observed. Total life estimates for notches were made by coupling an initiation life estimate with a propagation life estimate

Wind tunnel tests of Space Shuttle external tank insulation material in the aerothermal tunnel at elevated (1440 deg F) total temperatures

Tests of the space shuttle external tank foam insulation were conducted in the von Karman Gas Dynamics Facility Tunnel C. For these tests, Tunnel C was run at Mach 4 with a total temperature of 1440 F and a total pressure which varied from 30-100 psia. Cold wall heating rates were changed by varying the test article support wedge angle and by adding and removing a shock generator or a cylindrical protuberance. Selected results are presented to illustrate the test techniques and typical data obtained

Study of 23 day periodicity of Blazar Mkn501 in 1997

We confirm a 23 day periodicity during a large flare in 1997 for X-ray data of X-ray satellite RXTE all sky monitor(ASM), 2 TeV gamma ray data from Utah Seven Telescope and HEGRA, with a Fourier analysis. We found the three results to be the same with a newly estimated error. We confirm the presence of a frequency dependent power (1/f noise) in a frequency-power diagram. Further, we calculated a chance probability of the occurrence of the 23 day periodicity by considering the 1/f noise and obtained a chance probability 4.88*10^-3 for the HEGRA data: this is more significant than previous result by an order. We also obtained an identical peridoicity with another kind of timing analysis-epoch folding method for the ASM data and HEGRA data. We strongly suggest an existence of the periodicity. We divided the HEGRA data into two data sets, analyzed them with a Fourier method, and found an unstableness of the periodicity with a 3.4 sigma significance. We also analyzed an energy spectra of the X-ray data of a RXTE proportional counter array and we found that a combination of three parameters-a magnetic field, a Lorentz factor, and a beaming factor-is related to the periodicity.Comment: 25 page, 27 figures, acceptted by astroparticle physic

A Plan of Farm Organization for Hill Land Farms in Southeastern Ohio

Exact date of bulletin unknown.PDF pages: 2

Why paper mills clean up : determinants of pollution abatement in four Asian countries

The authors find strong evidence that despite weak or nonexistent formal regulation and enforcement of environmental standards, many plants in South and Southeast Asia are clean. At the same time, many plants are among the world's worst polluters. To account for the extreme variation among plants, the authors review evidence from a survey of pollution abatement by 26 pulp and paper plants in four countries: Bangladesh, India, Indonesia, and Thailand. They incorporate 3 sets of factors affecting pollution intensity: plant characteristics, economic considerations, and external pressure from the government and private stakeholders. They find that the level of pollution abatement is positively associated with scale and competitiveness, negatively associated with public ownership, and unaffected by foreign links (in ownership or financing). Informal regulation, or community pressure on plants works to abate pollution, with high income being a powerful predictor of effectiveness. Privatization, to the extent that it increases plant efficiency, can significantly improve environmental performance. To prevent environmental injustice in poor or marginalized communities, the authors conclude, governments may want to consider strategies for improving their participation, and may want to target regulation to address pollution problems among them.Environmental Economics&Policies,Water and Industry,Water Conservation,Pollution Management&Control,Sanitation and Sewerage,Environmental Economics&Policies,Water and Industry,Pollution Management&Control,Sanitation and Sewerage,TF030632-DANISH CTF - FY05 (DAC PART COUNTRIES GNP PER CAPITA BELOW USD 2,500/AL

Rational approximation and arithmetic progressions

A reasonably complete theory of the approximation of an irrational by rational fractions whose numerators and denominators lie in prescribed arithmetic progressions is developed in this paper. Results are both, on the one hand, from a metrical and a non-metrical point of view and, on the other hand, from an asymptotic and also a uniform point of view. The principal novelty is a Khintchine type theorem for uniform approximation in this context. Some applications of this theory are also discussed