3,819 research outputs found
Photoelectrocatalytic performances of nanostructured/decorated TiO 2 electrodes: Effect of wavelength and cell configuration
The behaviour of TiO2 based electrodes was investigated during the photoelectrocatalytic water splitting process. TiO2 nanotubes and compact oxide structures were obtained by electrochemical oxidation of Ti foils. A subsequent hydrothermal process carried out at both the nanotubular and compact oxide structures allowed decorating the structure by TiO2 nanoparticles. The synthesized TiO2 samples worked as photoanodes both in a bulk three electrode cell and in a thin gap cell. The results from measurements of the photocurrent and from electrochemical impedance spectroscopy were used to highlight a combined effect of the wavelength of the incident light and the kind of cell configuration, on the global performance of the systems. The results indicate that the decoration process does not result only in a simple increase of the specific surface, but it also determines a different concentration of the bulk and superficial sites in the electrode. The different response of the sites at different wavelengths, along with the accessibility of the electrolyte to the porous structure are evocated to justify the experimental behaviour observed
The Neutral Hydrogen Distribution in Merging Galaxies: Differences between Stellar and Gaseous Tidal Morphologies
We have mapped the neutral atomic gas (HI) in the three disk-disk merger
systems NGC 520, Arp 220, and Arp 299. These systems differ from the majority
of the mergers mapped in HI, in that their stellar and gaseous tidal features
do not coincide. In particular, they exhibit large stellar tidal features with
little if any accompanying neutral gas and large gas-rich tidal features with
little if any accompanying starlight. On smaller scales, there are striking
anti-correlations where the gaseous and stellar tidal features appear to cross.
We explore several possible causes for these differences, including dust
obscuration, ram pressure stripping, and ionization effects. No single
explanation can account for all of the observed differences. The fact that each
of these systems shows evidence for a starburst driven superwind expanding in
the direction of the most striking anti-correlations leads us to suggest that
the superwind is primarily responsible for the observed differences, either by
sweeping the features clear of gas via ram pressure, or by excavating a clear
sightline towards the starburst and allowing UV photons to ionize regions of
the tails.Comment: 16 pages, 5 figures, uses emulateapj.sty. To appear in the March 2000
issue of AJ. Version with full resolution figures is available via
http://www.cv.nrao.edu/~jhibbard/HIdisp/HIdisp.htm
Inspire
In lieu of an abstract, below is the essay\u27s first paragraph.
Writing about inspiration is a daunting task, not the least because the word itself has been overused to the point of oblivion. The temptation to include wonderful anecdotes of kind acts is great, but seems somehow to just borrow othersâ inspiration. Works of art, music and literature are described as âinspired,â as are our responses to them. Clothiers, the auto industry, even furnishing gurus claim inspiration as their productsâ genesis. Even broadcast news is compelled to include inspiring moments for their viewers by highlighting members of the community (or the nation or globe) who have done more, shared more, given more of themselves in an uncommon manner or for an unusual cause. These can bring a tear or a smile, but rarely do they truly inspire, in the sense of prompting similar action or commitment. Is this the true significance of the word, or has that been thoroughly obfuscated by its easy application to those caught in the midst of any emotional situation
Teacher Malpractice
Over the years, many classroom teachers in public schools have assumed\u27that as employees of local school boards, they were not subject to tort liability for injuries suffered by their students. Only those teachers who have found themselves a party to litigation involving an injured student ever fully recognized just how legally vulnerable teachers are to such actions
NLO Corrections to the kernel of the BKP-equations
We present results for the NLO kernel of the BKP equations for composite
states of three reggeized gluons in the Odderon channel, both in QCD and in N=4
SYM. The NLO kernel consists of the NLO BFKL kernel in the color octet
representation and the connected kernel, computed in the tree
approximation.Comment: 28 pages, 7 figure
Recommended from our members
The Wolf-Rayet population of Westerlund 1
New NTT/SOFI near-IR narrow-band imaging and spectroscopy reveals an additional four Wolf-Rayet (WR) stars in the massive cluster Westerlund 1, bringing the total WR population to 24. Sixteen of the WR stars in Wd1 have been classified WN5â11, while eight are WC8â9. An observed WR to RSG/YHG ratio of âŒ3 suggests an age of 4.5â5.0 Myr, with WR stars descended from 40â55MSolar progenitors. On the basis of dust and hard X-ray emission, we estimate that 40â65% are probable members of massive star binary systems
- âŠ