3,084 research outputs found
Mechanical properties of Rene-41 affected by rate of cooling after solution annealing
Investigation of Rene-41 cooling rate from 1975 to 1400 degrees F reveals that slow cooling improves high-temperature ductility and provides more uniform properties throughout a manifold. Ambient elongation and impact resistance are not significantly changed
Pre-weld heat treatment improves welds in Rene 41
Cooling of Rene 41 prior to welding reduces the incidence of cracking during post-weld heat treatment. The microstructure formed during the slow cooling rate favors elevated temperature ductility. Some vestiges of this microstructure are apparently retained during welding and thus enhance strain-age crack resistance in air
Heat treatment procedure to increase ductility of degraded nickel alloy
Tests demonstrate the room temperature ductility of degraded Rene 41 can be increased to acceptable values by solution heat treatment at a temperature of 2050 degrees to 2150 degrees F /1 to 2 hours/ and cooling through a controlled temperature range followed by normal aging in air /16 hours at 1400 degrees F/
Strain-age cracking in Rene 41 alloy
Weldability test determines the effects of material and process variables on the occurrence of strain-age cracking, and demonstrates effective and practical means for its reduction. Studies consist of tensile, impact, and stress-rupture tests
Considerations for insect and virus management in crops
Non-Peer ReviewedThe management of insect pests and viruses in crop fields can seem straightforward. In the most basic sense, a producer need only remove insects or virus vectors from their fields and the potentially costly problem is resolved. There are, however, many factors that might be can considered and which can influence the economics and efficacy of pest control choices. Examples of these include: the pest’s distribution, the available insecticidal materials, ecological factors such as the surrounding crops and weeds, and the crop itself. Greater understanding of these factors can lead to management tools and recommendations that result in yield protection but also reduced expenses on insecticides
Disseminating information or advocating peace? Journalists’ role perceptions in the face of conflict
Journalists play an important role in the formation of public opinion and can therefore be regarded as influential actors in conflict resolution. In Colombia, where the peace process remains a highly debated issue, the media are assumed to fuel polarization instead of dialogue. Indeed, deep societal divisions have been unveiled during last year’s plebiscite. In this environment, the concept of Peace Journalism has gained popularity among journalists, as it may promote a more nuanced debate. Against this backdrop, this study explores the role perceptions of Colombian journalists and their compatibility with the premises of Peace Journalism. To provide in-depth insights into journalists’ role conceptions, 16 semi-structured interviews with Colombian journalists were conducted. The results indicate that journalists hold a very active stance and want to influence and engage the public with their work, closely identifying with the role of the public mobilizer
A genetic and tissue-engineering approach to improving canine olfactory ensheathing cell transplant for spinal cord injury
Gravitational wave recoil in Robinson-Trautman spacetimes
We consider the gravitational recoil due to non-reflection-symmetric
gravitational wave emission in the context of axisymmetric Robinson-Trautman
spacetimes. We show that regular initial data evolve generically into a final
configuration corresponding to a Schwarzschild black-hole moving with constant
speed. For the case of (reflection-)symmetric initial configurations, the mass
of the remnant black-hole and the total energy radiated away are completely
determined by the initial data, allowing us to obtain analytical expressions
for some recent numerical results that have been appeared in the literature.
Moreover, by using the Galerkin spectral method to analyze the non-linear
regime of the Robinson-Trautman equations, we show that the recoil velocity can
be estimated with good accuracy from some asymmetry measures (namely the first
odd moments) of the initial data. The extension for the non-axisymmetric case
and the implications of our results for realistic situations involving head-on
collision of two black holes are also discussed.Comment: 9 pages, 6 figures, final version to appear in PR
Impact of UV wavelength and curing time on the properties of spin-coated low-k films
Advanced spin-on k 2.3 films with similar to 40% porosity were enabled by liquid phase self-assembly (LPSA) mechanism on Si substrates. UV-assisted thermal template removal is investigated as a faster alternative to the conventional thermal process. The as-deposited films were exposed to narrow-band UV light of 172 nm, 222 nm, 254 nm or 185/254 nm at 400 degrees C for different time. The optical, mechanical, chemical and electrical properties of the resulting films are discussed in this work. Photons with wavelength of about 172 nm from one side are detrimental to the electrical and chemical properties of the low-k films hut from the other side notably improve the porous low-k mechanical properties. Exposure to 222 nm light as short as 3 min, is more efficient in terms of template removal when compared to 2h thermal cure, while in both cases similar mechanical and electrical properties are reported. UV-cure using 254 nm or dual band 254/185 nm photons seem to have a minor contribution to the template removal efficiency for the applied doses. Higher doses are necessary in order to better understand the effective contribution of these photon energies. Finally, the HF etching mechanism is discussed
- …