For all your statistics needs. The "Plastic Debris in the World's Oceans Report - UNEP" www.unep.org/regionalseas/marinelitter/.../docs/plastic_ocean_report.pdf
"Densities of plastic debris (Moore et al. 2001). Using nets to collect debris, the abundance of floating plastic averaged 334,271 pieces/km2"
More worrying maybe is (http://www.ncbi.nlm.nih.gov/pubmed/22610295)
"Our oceans eventually serve as a sink for these small plastic particles ("UV degraded surface plastic") and in one estimate, it is thought that 200,000 microplastics per km(2) of the ocean's surface commonly exist."
I wonder how much energy you can extract from the ocean in a responsible way... Mixing up different thermal layers would probably a quite an influence on ecology.
The last available assessment report on the ecological impact seems to date from 1981 which would need to be brought up to current standards. On the other hand, this system could have a positive influence on fish population as deep cold water brings nutrients to the surface. The cold water could also be used to lower sea surface temperatures and affect hurricane genesis!
In 2002, the European Space Agency began a program called Don Quijote to find out how best to perform such a deflection.
Now, Stephen Wolters at the Open University in the UK and a few friends have published a new analysis of the mission saying that measuring the change in orbit is not enough. Instead, the spacecraft needs to characterise the impact in detail, determining the density of the material near the asteroid's surface, the size of the surface grains as well as the mass and speed distribution of the impact ejecta.
Ref: arxiv.org/abs/1107.4229: Measurement Requirements For A Near-Earth Asteroid Impact Mitigation Demonstration Mission
Dynamics of dissipation local vibrations to the surrounding substrate is a key issue in friction between sliding surfaces as well as in boundary lubrication.
also interesting (for the Earth Science girls): Nilton Renno of the University of Michigan, who studies how rocket plumes from Mars landers affect the Martian surface.
Some locations on Mars are known to have water ice just below the surface, but how much has remained unclear. Dundas et al. used data from two orbiting spacecraft to examine eight locations where erosion has occurred. This revealed cliffs composed mostly of water ice, which is slowly sublimating as it is exposed to the atmosphere. The ice sheets extend from just below the surface to a depth of 100 meters or more and appear to contain distinct layers, which could preserve a record of Mars' past climate. They might even be a useful source of water for future human exploration of the red planet.
Prince Rupert's drops (PRDs), also known as Batavian tears, have been in existence since the early 17th century. They are made of a silicate glass of a high thermal expansion coefficient and have the shape of a tadpole. Typically, the diameter of the head of a PRD is in the range of 5-15 mm and that of the tail is 0.5 to 3.0 mm. PRDs have exceptional strength properties: the head of a PRD can withstand impact with a small hammer, or compression between tungsten carbide platens to high loads of ∼15 000 N, but the tail can be broken with just finger pressure leading to catastrophic disintegration of the PRD. We show here that the high strength of a PRD comes from large surface compressive stresses in the range of 400-700 MPa, determined using techniques of integrated photoelasticity. The surface compressive stresses can suppress Hertzian cone cracking during impact with a small hammer or compression between platens. Finally, it is argued that when the compressive force on a PRD is very high, plasticity in the PRD occurs, which leads to its eventual destruction with increasing load.
By focusing our defense resources into a space-superiority platform and weapon system such as a Death Star, the government can spur job creation in the fields of construction, engineering, space exploration, and more, and strengthen our national defense.
I want to sign, it is totally a meaningful idea .... ! Just remember not to put the nuclear energy source at the end of a tunnel which has an opening on the surface :)
I thought you were supposed to do this with petrol... |:-[
It's by the way cool to see how the milk seems to flow very differently from what one might expect from water: it seems to flow in a few thick streams instead of wetting the whole person... Since the surface tension of milk seems to be lower than that of water (http://journals.cambridge.org/action/displayAbstract;jsessionid=908B02C3825E97162B9D60DA615EAC96.journals?fromPage=online&aid=5146540)
this is surprising. It might very well be an effect of the colloidal nature of milk as it is water in which semi-solid fat particles are suspended. So like the cornstarch mix that we have seen in the office there might be some dynamic jamming going on leading to a higher viscosity (at high shear rates).
After all they might be doing science...
nice comment Johannes ... if you add a bit of Kleopatre, e.g. why bathing in milk helped her fool Marcus Antonius, your comment would be fully interdisciplinary :-)
you mean it would include History or Psychology? I would understand why Marcus Antonius might get fooled by a bathing beauty - but milk? DONKEY MILK?!? That's just wrong... :-[
"chances are that if 700 passengers are flown annually, up to 10 of them might not survive the flight in the first years of the operations."
most remarkable also the question who is to blame if a dead and burned space tourist corps comes crashing down from the sky into your car.
How sure is the information that a human body would not completely burn / ablate during atmospheric re-entry? I am not aware of any material ground tests in a plasma wind tunnel confirming that human tissue would survive re-entry from LEO.
Since a steak would not even be cooked by dropping it from very high altitudes (http://what-if.xkcd.com/28/) I would doubt that a space tourists body would desintegrate by atmospheric re-entry.
Funny link, however, some things are not clear enough:
1. Ablation rate is unknown
2. What are the entry conditions? The link suggests that the steak is just dropped (no initial velocity).
3. What about the ballistic coefficient?
4. How would the entry body orientation? It would be a quite non-steady state configuration I guess with heavy accelerations.
5. How would vacuum exposure impact on the water in the body/steak and what would be the consequence for ablation behaviour?
6. Does surface chemistry play a role (not ablation, but catalysis)?
My conclusion: the example with the steak is a funny and not so bad exercise, not more.
Abstract: The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields ($B\approx 10^{13}$ G), radiation from these sources is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission.
A new blob-like robot described in the journal Advanced Robotics uses springs, feet, "protoplasm" and a distributed nervous system to move in a manner inspired by the slime mold Physarum polycepharum. Watch it ooze across a flat surface, The Blob style: Skip to 1:00 if you just want to be creeped out by its life-like quivering.
"The latest idea comes from engineers at Glasgow's University of Strathclyde who suggest that a swarm of laser-wielding satellites could nudge Earth-bound asteroids off their collision course.... One proposed deflection technique involves using lasers to pulverize the surface of the asteroid, ejecting tiny bits of rock that would act as a propellant and push it onto a different course."
Researchers in the US have unveiled a new technique to repair nanometre-sized defects using oil-based microcapsules filled with a nanoparticle solution.
Just over six years ago, we reported that Nissan had developed a "Scratch Guard Coat" paint designed to repair scratches on not only cars, but on painted surfaces in general.
...
The Scratch Shield paint is made from polyrotaxane, which has a chemical structure that is able to react and change back to its original shape and fill the gap that results from a fine scratch.