8,276 research outputs found
Solenoid valve performance characteristics studied
Current and voltage waveforms of a solenoid coil are recorded as the valve opens and closes. Analysis of the waveforms with respect to time and the phase of the valve cycle accurately describes valve performance
Stress corrosion cracking of titanium alloys: SCC velocity: concentration of TiCl3
Stress corrosion cracking of titanium alloys, velocity of cracking in aqueous and methanol solutions and halogenated organic solvents, concentration of TiCl3 in crack
The Effect of NAG–thiazoline on Morphology and Surface Hydrophobicity of Escherichia Coli
The β-hexosaminidase inhibitor and structural analog of the putative oxazolium reaction intermediate of lytic transglycosylases, N-acetylglucosamine thiazoline (NAG–thiazoline), was synthesized in 46% overall yield and tested as an inhibitor of Escherichia coli growth. NAG–thiazoline, at concentrations up to 1 mg/ml, was not found to affect the viability of E. coli DH5α
Stress corrosion cracking of titanium alloys: Studies of cracks in thin specimens; SCC of Ti-6Al-4V in chloride, iodide and fluoride solutions; stress corrosion cracking in molten salts; electrochemistry of freshly generated titanium surfaces
Electrochemistry of freshly generated titanium surfaces and stress corrosion cracking in aqueous solutions and in molten salt
Fundamental investigation of stress corrosion cracking
Two principle areas studied were stress corrosion crack growth rates of a titanium alloy in liquid environments containing halide ions and pitting corrosion of titanium in bromide solutions. Two initial assumptions were made, that the rate of propagation was controlled by a macroscopic solution parameter and that this parameter was viscosity. A series of solutions were prepared using lithium chloride as the solute and water, methanol, glycerin, formic acid, acetone, dimethyl sulphoxide, etc. As solvents, these solutions were prepared with a 5:1 solvent-solute ratio. Viscosity was varied by changing the temperature and it was found: (1) In all solvents the velocity of cracking was proportional to the reciprocal of the viscosity. (2) Each solvent gave a separate relationship, (3) The temperature dependence and numerical values for the apparent activation energy of cracking and viscosity were the same
Stress Corrosion Cracking of titanium alloys - SCC of aluminum alloys, polarization of titanium alloys in hydrogen chloride and correlation of titanium and aluminum SCC behavior Quarterly progress report, 1 Oct. 1968 - 31 Mar. 1969
Stress corrosion cracking of titanium alloys and aluminum alloy
Observations of large raptors in northeast Sudan
During a targeted shorebird survey of wetlands along Sudan’s Red Sea Coast in January 2010 we took the opportunity to gather limited baseline information on large raptors within an understudied region. One 430 km transect was completed while driving from Atbara to Port Sudan on 19 January. Thirty Egyptian Vultures Neophron percnopterus were recorded at a mean of 7 birds per 100 km over 6.15 hours, and eight unidentified large vultures were seen. From subsequent ad hoc records gathered during 20 additional vehicle hours covering 450 km of coastline, we identified populations of Lappet-faced Vulture Torgos tracheliotos and Hooded Vulture Necrosyrtes monachus and migrant Steppe Eagle Aquila nipalensis
Stress corrosion cracking of titanium alloys - Electrochemical mass transport kinetic model, metallurgical and mechanical effects, and proposed relation of electrochemical, metallurgical and mechanical effects Quarterly progress report, 1 Apr. - 30 J
Electrochemical mass transport kinetic model used to study metallurgical and mechanical effects of titanium alloy stress corrosion crackin
A classical statistical model for distributions of escape events in swept-bias Josephson junctions
We have developed a model for experiments in which the bias current applied
to a Josephson junction is slowly increased from zero until the junction
switches from its superconducting zero-voltage state, and the bias value at
which this occurs is recorded. Repetition of such measurements yields
experimentally determined probability distributions for the bias current at the
moment of escape. Our model provides an explanation for available data on the
temperature dependence of these escape peaks. When applied microwaves are
included we observe an additional peak in the escape distributions and
demonstrate that this peak matches experimental observations. The results
suggest that experimentally observed switching distributions, with and without
applied microwaves, can be understood within classical mechanics and may not
exhibit phenomena that demand an exclusively quantum mechanical interpretation.Comment: Eight pages, eight figure
The relationship between propagule pressure and establishment success in alien bird populations: a re-analysis of Moulton & Cropper (2019)
A recent analysis by Moulton & Cropper (2019) of a global dataset on alien bird population introductions claims to find no evidence that establishment success is a function of the size of the founding population. Here, we re-analyse Moulton & Cropper’s data and show that this conclusion is based on flawed statistical methods—their data in fact confirm a strong positive relationship between founding population size and establishment success. We also refute several non-statistical arguments against the likelihood of such an effect presented by Moulton & Cropper. We conclude that a core tenet of population biology—that small populations are more prone to extinction—applies to alien populations beyond their native geographic range limits as much as to native populations within them
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