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pacome delva

Girls Get Math: It's Culture That's Skewed - 2 views

www.livescience.com/...090601-gender-math.html

sociology math

shared by pacome delva on 19 Apr 10 - Cached
  • "There's a gender stereotype that boys are better at math than girls are, and stereotypes die very hard," Hyde told LiveScience. "Teachers and parents still believe that boys are better at math than girls are." The researchers provide several possible cultural factors keeping females from excelling in math, including classroom dynamics in which teachers pay more attention to boys, while even mathematically gifted girls are not nurtured. In addition, stereotypes may drive guidance counselors and others to discourage girls from taking engineering courses.
  • Nina Nadine Ridder on 26 Apr 10
     
    The guidance counselor at my high school discouraged me to study physics but was very excited when I was contemplating to become a teacher. Maybe I should send her this article...
  • Luzi Bergamin on 26 Apr 10
     
    Oh yeah, real new!! And in the 90s it was obvious that girls are smarter but discriminated, today its obvious that the poor boys are neglected; some years ago female teachers were proven to discriminate even stronger against girls than male teachers and today politicians demand more male teachers... because they would pay more attention to the neglected boys! Great, that's what I like about sociological research, every couple of years one can sell the same old story again and again and again... sorry, I'm in a real bullshitter mood today!
  • Nicholas Lan on 27 Apr 10
     
    gotta agree with luzi here. girls at secondary school in the UK have been outperforming boys for years now after numerous government programmes. As to guidance counsellors - if they were any good at guidance wouldn't they have better jobs?
Giusi Schiavone

coming back to the Moon - 2 views

www.googlelunarxprize.org/...about-the-prize

shared by Giusi Schiavone on 28 Feb 11 - Cached
  • Giusi Schiavone on 28 Feb 11
     
    The $30 million Google Lunar X PRIZE will be awarded to the first privately funded teams to build robots that successfully land on the lunar surface, explore the Moon by moving at least 500 meters (~1/3 of a mile), and return high definition video and imagery. The Google Lunar X PRIZE expires whenever all prizes are claimed, or at the end of 2015. As of midnight on December 31st, 2010, the team registration for the Google Lunar X PRIZE is closed. No additional applicants will be accepted to join the competition. ...too late
  • LeopoldS on 02 Mar 11
     
    please see the act report on this from a few years ago - its on the wiki - should we maybe make an update analysis? any volunteers? Giusi?
  • Giusi Schiavone on 02 Mar 11
     
    I'll have a look
Luís F. Simões

Shell energy scenarios to 2050 - 6 views

www.shell.com/...shell_energy_scenarios_2050

energy future forecast politics economy climate_change

shared by Luís F. Simões on 09 Mar 11 - No Cached
  • Luís F. Simões on 09 Mar 11
     
    just in case you were feeling happy and optimistic
  • ...7 more comments...
  • Francesco Biscani on 09 Mar 11
     
    An energy scenario published by an oil company? Allow me to be sceptical...
  • Joris _ on 10 Mar 11
     
    Indeed, Shell is an energy company, not just oil, for some time now ... The two scenarii are, in their approach, dependant of economic and political situation, which is right now impossible to forecast. Reference to Kyoto is surprising, almost out-dated! But overall, I find it rather optimistic at some stages, and probably the timeline (p37-39) is unlikely with recent events.
  • Luís F. Simões on 10 Mar 11
     
    the report was published in 2008, which explains the reference to Kyoto, as the follow-up to it was much more uncertain at that point. The Blueprint scenario is indeed optimistic, but also quite unlikely I'd say. I don't see humanity suddenly becoming so wise and coordinated. Sadly, I see something closer to the Scramble scenario as much more likely to occur.
  • LeopoldS on 12 Mar 11
     
    not an oil company??? please have a look at the percentage of their revenues coming from oil and gas and then compare this with all their other energy activities together and you will see very quickly that it is only window dressing ... they are an oil and gas company ... and nothing more
  • Joris _ on 14 Mar 11
     
    not JUST oil. From a description: "Shell is a global group of energy and petrochemical companies." Of course revenues coming from oil are the biggest, the investment turnover on other energy sources is small for now. Knowing that most of their revenues is from an expendable source, to guarantee their future, they invest elsewhere. They have invested >1b$ in renewable energy, including biofuels. They had the largest wind power business among so-called "oil" companies. Oil only defines what they do "best". As a comparison, some time ago, Apple were selling only computers and now they sell phones. But I would not say Apple is just a phone company.
  • LeopoldS on 14 Mar 11
     
    window dressing only ... e.g. Net cash from operating activities (pre-tax) in 2008: 70 Billion$ net income in 2008: 26 Billion revenues in 2008: 88 Billion Their investments and revenues in renewables don't even show up in their annual financial reports since probably they are under the heading of "marketing" which is already 1.7 Billion $ ... this is what they report on their investments: Capital investment, portfolio actions and business development Capital investment in 2009 was $24 billion. This represents a 26% decrease from 2008, which included over $8 billion in acquisitions, primarily relating to Duvernay Oil Corp. Capital investment included exploration expenditure of $4.5 billion (2008: $11.0 billion). In Abu Dhabi, Shell signed an agreement with Abu Dhabi National Oil Company to extend the GASCO joint venture for a further 20 years. In Australia, Shell and its partners took the final investment decision (FID) for the Gorgon LNG project (Shell share 25%). Gorgon will supply global gas markets to at least 2050, with a capacity of 15 million tonnes (100% basis) of LNG per year and a major carbon capture and storage scheme. Shell has announced a front-end engineering and design study for a floating LNG (FLNG) project, with the potential to deploy these facilities at the Prelude offshore gas discovery in Australia (Shell share 100%). In Australia, Shell confirmed that it has accepted Woodside Petroleum Ltd.'s entitlement offer of new shares at a total cost of $0.8 billion, maintaining its 34.27% share in the company; $0.4 billion was paid in 2009 with the remainder paid in 2010. In Bolivia and Brazil, Shell sold its share in a gas pipeline and in a thermoelectric power plant and its related assets for a total of around $100 million. In Canada, the Government of Alberta and the national government jointly announced their intent to contribute $0.8 billion of funding towards the Quest carbon capture and sequestration project. Quest, which is at the f
  • Joris _ on 14 Mar 11
     
    thanks for the info :) They still have their 50% share in the wind farm in Noordzee (you can see it from ESTEC on a clear day). Look for Shell International Renewables, other subsidiaries and joint-ventures. I guess, the report is about the oil branch. http://sustainabilityreport.shell.com/2009/servicepages/downloads/files/all_shell_sr09.pdf http://www.noordzeewind.nl/
  • LeopoldS on 16 Mar 11
     
    no - its about Shell globally - all Shell .. these participations are just peanuts please read the intro of the CEO in the pdf you linked to: he does not even mention renewables! their entire sustainability strategy is about oil and gas - just making it (look) nicer and environmentally friendlier
  • Joris _ on 16 Mar 11
     
    Fair enough, for me even peanuts are worthy and I am not able to judge. Not all big-profit companies, like Shell, are evil :( Look in the pdf what is in the upstream and downstream you mentionned above. Non-shell sources for examples and more objectivity: http://www.nuon.com/company/Innovative-projects/noordzeewind.jsp http://www.e-energymarket.com/news/single-news/article/ferrari-tops-bahrain-gp-using-shell-biofuel.html thanks.
LeopoldS

SBIR/STTR Additional Phase 2 Selection Announcement - 0 views

sbir.gsfc.nasa.gov/...firm.html

technology innovation NASA high-tech

shared by LeopoldS on 28 Aug 09 - Cached
  • LeopoldS on 28 Aug 09
     
    intersting list of new NASA ITI like technology developments ...
Juxi Leitner

A More Affordable, High G force Magnetic Space Launcher Proposal - 0 views

nextbigfuture.com/...ble-high-g-force-magnetic.html

magnetic launcher

shared by Juxi Leitner on 17 Sep 09 - No Cached
  • The launcher operates 350 days and launches 100 kg payload every 30 min (This means about 5000kg/day and 1750 tons/year). Then additional cost from installation is $2.86/kg then total cost is $6/kg
  • The railgun does not have this limit, but produces some engineering problems such as the required short (pulsed) gigantic surge of electric power, sliding contacts for some millions of amperes current, storage of energy, etc.
  • A short rail way (412 m) would launch 7500 Gs into orbit.
  • Juxi Leitner on 17 Sep 09
     
    another rail-gun try
Paul N

Rocks Made of Plastic Found on Hawaiian Beach - 1 views

news.sciencemag.org/...e-plastic-found-hawaiian-beach

science

shared by Paul N on 08 Sep 14 - No Cached
  • Paul N on 08 Sep 14
     
    Plastic may be with us a lot longer than we thought. In addition to clogging up landfills and becoming trapped in Arctic ice, some of it is turning into stone. Scientists say a new type of rock cobbled together from plastic, volcanic rock, beach sand, seashells, and corals has begun forming on the shores of Hawaii. The Anthropocene might just be on its way
Thijs Versloot

Relativistic rocket: Dream and reality - 3 views

www.sciencedirect.com/...S009457651400040X

propulsion antimatter relativistic

shared by Thijs Versloot on 27 Mar 14 - No Cached
  • Thijs Versloot on 27 Mar 14
     
    An exhaustive overview of all possible advanced rocket concepts, eg.. "As an example, consider a photon rocket with its launching mass, say, 1000 ton moving with a constant acceleration a =0.1 g=0.98 m/s2. The flux of photons with E γ=0.5 MeV needed to produce this acceleration is ~1027/s, which corresponds to the efflux power of 1014 W and the rate of annihilation events N'a~5×1026 s−1 [47]. This annihilation rate in ambiplasma l -l ann corresponds to the value of current ~108 A and linear density N ~2×1018 m−1 thus any hope for non-relativistic relative velocity of electrons and positrons in ambiplasma is groundless." And also, even if it would work, then one of the major issues is going to be heat dispersal: "For example, if the temperature of radiator is chosen T=1500 K, the emitting area should be not less than 1000 m2 for Pb=1 GW, not less than 1 km2 for Pb=1 TW, and ~100 km2 for Pb=100 TW, assuming ε=0.5 and δ=0.2. Lower temperature would require even larger radiator area to maintain the outer temperature of the engine section stable for a given thermal power of the reactor."
  • ...2 more comments...
  • johannessimon81 on 27 Mar 14
     
    We were also discussing a while ago a propulsion system using the relativistic fragments from nuclear fission. That would also produce an extremely high ISP (>100000) with a fairly high thrust. Never really got any traction though.
  • dejanpetkow on 29 Mar 14
     
    I absolutely do not see the point in a photon rocket. Certainly, the high energy releasing nulcear processes (annihilation, fusion, ...) should rather be used to heat up some fluid to plasma state and accelerate it via magnetic nozzle. This would surely work as door-opener to our solar system...and by the way minimize the heat disposal problem if regenerative cooling is used.
  • Thijs Versloot on 31 Mar 14
     
    The problem is not achieving a high energy density, that we can already do with nuclear fission, the question however is how to confine or harness this power with relatively high efficiency, low waste heat and at not too crazy specific mass. I see magnetic confinement as a possibility, yet still decades away and also an all-or-nothing method as we cannot easily scale this up from a test experiment to a full-scale system. It might be possible to extract power from such a plasma, but definitely well below breakeven so an additional power supply is needed. The fission fragments circumvent these issues by a more brute force approach, thereby wasting a lot of energy for sure but at the end probably providing more ISP and thrust.
  • dejanpetkow on 03 Apr 14
     
    Sure. However, the annihilation based photon rocket concept unifies almost all relevant drawbacks if we speak about solar system scales, making itself obsolete...it is just an academic testcase.
darioizzo2

Volumetric additive manufacturing of silica glass with microscale computed axial lithog... - 2 views

www.science.org/...science.abm6459

shared by darioizzo2 on 20 Apr 22 - No Cached
jcunha liked it
  • darioizzo2 on 20 Apr 22
     
    The technology that Derek is "following"
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