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Daniel Hennes

V3Solar puts a new spin on PV efficiency - 1 views

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    "V3Solar has developed a cone-shaped solar energy harvester that is claimed to generate over 20 times more electricity than a flat panel thanks to a combination of concentrating lenses, dynamic spin, conical shape, and advanced electronics."
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    Hmm.. that seems counter intuitive... how would it ever be that much better than a flat panel? Rotating the PV will only make sure only parts are illuminated. Operating temperature is a better argument, but that comes at the cost of exposure. Came across this little gem of a webpage, maybe we should outsource our impossibility EM drive work next time? :) https://www.metabunk.org/debunked-v3solars-spinning-solar-panel-cone-spin-cell-coolspin.t1166/
LeopoldS

Decreasing cost of PV solar panels change the use of CSP in Blythe Project - 0 views

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    interesting move ...
LeopoldS

Sphelar Power Corporation - 0 views

shared by LeopoldS on 14 Dec 12 - No Cached
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    Commercial project for wearable solar cells by 2015 ...
Lionel Jacques

Artificial energy harvesting tree - 1 views

shared by Lionel Jacques on 11 Jan 12 - Cached
LeopoldS liked it
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    The idea has been around for already some time (2008) but I like it despite the challenges/trade-off: visible vs IR photovoltaics, black leaves would be better... Piezo + classical PV would already be great... Optimizing the leave shape & distribution for both wind and sun energy harvesting could be interesting...
Thijs Versloot

Black metals - 3 views

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    Using random nanostructuring highly absorptive materials were made which are of interest for photovoltaic or thermovoltaic applications
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    Yes, Black Metal is very good - pure hate! \m/
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    Yes! Black Metal... definitely something the ACT should look into
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    Black Metal...sounds like something for the ACT Magic Cards. But apart from that - is it possible to shift the PV type of absorption into gamma ray spectrum?
johannessimon81

High efficiency solid state heat engine - 0 views

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    We discussed this today during coffee. The inventor claims that he claims that a pressure differential can push hydrogen through a proton conductive membrane (thereby stripping off the electrons) which flow through an electric circuit and provide electric power. The type of membrane is fairly similar to that found in a hydrogen fuel cell. If the pressure differential is cause by selective heating this is in essence a heat engine that directly produces electricity. The inventor claims that this could be a high efficiency alternative to thermoelectric devices and could even outperform PV and Sterling engines with an efficiency close to that of fuel cells (e.g., ~60% @ dT=600K). I could not find any scientific publications as the inventor is not affiliated to any University - he has however an impressive number of patents from a very wide field (e.g., the "Super Soaker" squirt gun) and has worked on several NASA and US military projects. His current research seams to be funded by the latter as well. Here are some more links that I found: http://www.theatlantic.com/magazine/archive/2010/11/shooting-for-the-sun/308268/ http://www.johnsonems.com/?q=node/13 http://scholar.google.nl/scholar?q=%22lonnie+g+johnson%22+&btnG=&hl=nl&as_sdt=0%2C5
annaheffernan

Solar panels perform better when listening to music - 2 views

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    Turn on Metal and they will boost their efficiency by 666%!
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    the title is at best misleading ... they add piezoelectrics into PV cells ... "manufacturing a piezoelectric material, zinc oxide nanorods, into the solar cells increased their efficiency when sound waves were played"
LeopoldS

Solar Flower high concentration PV - 3 views

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    interesting collaboration ... unfortunately no prices yet available
Dario Izzo

Optimal Control Probem in the CR3BP solved!!! - 7 views

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    This guy solved a problem many people are trying to solve!!! The optimal control problem for the three body problem (restricted, circular) can be solved using continuation of the secondary gravity parameter and some clever adaptation of the boundary conditions!! His presentation was an eye opener ... making the work of many pretty useless now :)
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    Riemann hypothesis should be next... Which paper on the linked website is this exactly?
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    hmmm, last year at the AIAA conference in Toronto I presented a continuation approach to design a DRO (three-body problem). Nothing new here unfortunately. I know the work of Caillau, although interesting what is presented was solved 10 years ago by others. The interest of his work is not in the applications (CR3BP), but in the research of particular regularity conditions that unfortunately make the problem limited practically. Look also at the work of Mingotti, Russel, Topputo and other for the (C)RTBP. Smart-One inspired a bunch of researchers :)
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    Topputo and some of the others 'inspired' researchers you mention are actually here at the conference and they are all quite depressed :) Caillau really solves the problem: as a one single phase transfer, no tricks, no misconvergence, in general and using none of the usual cheats. What was produced so far by other were only local solutions valid for the particular case considered. In any case I will give him your paper, so that he knows he is working on already solved stuff :)
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    Answer to Marek: the paper you may look at is: Discrete and differential homotopy in circular restricted three-body control
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    Ah! with one single phase and a first order method then it is amazing (but it is still just the very particular CRTBP case). The trick is however the homotopy map he selected! Why this one? Any conjugate point? Did I misunderstood the title ? I solved in one phase with second order methods for the less restrictive problem RTBP or simply 3-body... but as a strict answer to your title the problem has been solved before. Nota: In "Russell, R. P., "Primer Vector Theory Applied to Global Low-Thrust Trade Studies," JGCD, Vol. 30, No. 2", he does solve the RTBP with a first order method in one phase.
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    I think what is interesting is not what he solved, but how he solved the problem. But, are means more important than end ... I dunno
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    I also loved his method, and it looked to me that is far more general than the CRTBP. As for the title of this post, OK maybe it is an exageration as it suggests that no solution was ever given before, on the other end, as Marek would say "come on guys!!!!!"
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    The generality has to be checked. Don't you think his choice of mapping is too specific? he doesn't really demonstrate it works better than other. In addition, the minimum time choice make the problem very regular (i guess you've experienced that solving min time is much easier than mass max, optimality-wise). There is still a long way before maximum mass+RTBP, Topputo et al should be re-assured :p Did you give him my paper, he may find it interesting since I mention the homotopy on mu but for max mass:)
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    Joris, that is the point I was excited abut, at the conference HE DID present solutions to the maximum mass problem!! One phase, from LEO to an orbit around the moon .. amazing :) You will find his presentation on line.... (according to the organizers) I gave him the reference to you paper anyway, but no pdf though as you did not upload it on our web pages and I could not find it in the web. So I gave him some bibliography I had with be from the russians, and from Russell, Petropoulos and Howell, As far as I know these are the only ones that can hope to compete with this guy!!
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    for info only, my phd, in one phase: http://pdf.aiaa.org/preview/CDReadyMAST08_1856/PV2008_7363.pdf I prefered Mars than the dead rock Moon though!
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    If you send me the pdf I can give it to the guy .. the link you gave contains only the first page ... (I have no access till monday to the AIAA thingy)
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    this is why I like this Diigo thingy so much more than delicious ...
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    What do you mean by this comment, Leopold? ;-) Jokes apart: I am following the Diigo thingy with Google Reader (rss). Obviously, I am getting the new postings. But if someone later on adds a comment to a post, then I can miss it, because the rss doesn't get updated. Not that it's a big problem, but do you guys have a better solution for this? How are you following these comments? (I know that if you have commented an entry, then you get the later updates in email.) (For example, in google reader I can see only the first 5 comments in this entry.)
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    I like when there are discussions evolving around entries
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    and on your problem with the RSS Tamas: its the same for me, you get the comments only for entries that you have posted or that you have commented on ...
LeopoldS

Interesting New Products and Inventions: Liquid Solar Array Power Generator - 0 views

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    nice concept - still have to look closer into it ...
ESA ACT

Japanese consortium disguises solar cells as leaves - Engadget - 0 views

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    remember that I wanted to do this at a University lab course! ...LS
ESA ACT

ScienceDirect - Advances in Colloid and Interface Science : nanoparticle polymer PV cells - 0 views

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    of interest? -LS
annaheffernan

Plasmons excite hot carriers - 1 views

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    The first complete theory of how plasmons produce "hot carriers" has been developed by researchers in the US. The new model could help make this process of producing carriers more efficient, which would be good news for enhancing solar-energy conversion in photovoltaic devices.
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    I did not read the paper but what is further down written in the article, does not give much hope that this actually gives much more insight than what we had nor that it could be used in any way to improve current PV cells soon: e.g. "To fully exploit these carriers for such applications, researchers need to understand the physical processes behind plasmon-induced hot-carrier generation. Nordlander's team has now developed a simple model that describes how plasmons produce hot carriers in spherical silver nanoparticles and nanoshells. The model describes the conduction electrons in the metal as free particles and then analyses how plasmons excite hot carriers using Fermi's golden rule - a way to calculate how a quantum system transitions from one state into another following a perturbation. The model allows the researchers to calculate how many hot carriers are produced as a function of the light frequency used to excite the metal, as well as the rate at which they are produced. The spectral profile obtained is, to all intents and purposes, the "plasmonic spectrum" of the material. Particle size and hot-carrier lifetimes "Our analyses reveal that particle size and hot-carrier lifetimes are central for determining both the production rate and the energies of the hot carriers," says Nordlander. "Larger particles and shorter lifetimes produce more carriers with lower energies and smaller particles produce fewer carriers, but with higher energies."
LeopoldS

Light-induced reversal of ion segregation in mixed-halide perovskites | Nature Materials - 0 views

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    Light-induced reversal of ion segregation in mixed-halide perovskites
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