Group items tagged

Sante, Andreas, Luzi, Pacome ... we need you: "But recently White calculated what would happen if the shape of the ring encircling the spacecraft was adjusted into more of a rounded donut, as opposed to a flat ring. He found in that case, the warp drive could be powered by a mass about the size of a spacecraft like the Voyager 1 probe NASA launched in 1977.

Furthermore, if the intensity of the space warps can be oscillated over time, the energy required is reduced even more, White found.

"The findings I presented today change it from impractical to plausible and worth further investigation," White told SPACE.com. "The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab.""

To me, this looks a little bit like the claim "infinity minus one is a little bit less than infinity"...

Luzi I miss you ...

nice indeed! " Triggered by commonly available ambient mechanical energy such as human footfalls, a NG with size smaller than a human palm can generate maximum short-circuit current of 2 mA, delivering instantaneous power output of 1.2 W to external load. The power output corresponds to an area power density of 313 W/m2 and a volume power density of 54 268 W/m3 at an open-circuit voltage of 1200 V. An energy conversion efficiency of 14.9% has been achieved. The power was capable of instantaneously lighting up as many as 600 multicolor commercial LED bulbs. The record high power output for the NG is attributed to optimized structure, proper materials selection and nanoscale surface modification. This work demonstrated the practicability of using NG to harvest large-scale mechanical energy, such as footsteps, rolling wheels, wind power, and ocean waves."

You should be able to put it also in your shoes such that you may be able to power some gadgets. Thinking about it, I have seen many kids already running around with brightly lit sneakers!

tesla announcing home batteries at 350$/kW

Let's do some simple maths... Here in UK, example "economy 7" tarif yields night kWh approx. 12 pence cheaper than during day. Let's say the goal is to store energy equivalent to running a 2kW storage heater for 6 hours during the day. We need 12 kWh, so 12 times $350 this means need to spend approx. 1920 pounds for batteries. Time to break even at ROI: 1920 / 0.12 ~ 7.3 years... And this is assuming using the heater 365 days a year, and quite an expensive tariff (prepaid). SIWB :-)

Also need to take into account that battery capacity tends to go down with time and usage

The principle behind that is Nantenna.

this is fantastic!!!! waiting of somebody to make this happen since years The size of the gap is critical because it creates an ultra-fast tunnel junction between the rectenna's two electrodes, allowing a maximum transfer of electricity. The nanosized gap gives energized electrons on the rectenna just enough time to tunnel to the opposite electrode before their electrical current reverses and they try to go back. The triangular tip of the rectenna makes it hard for the electrons to reverse direction, thus capturing the energy and rectifying it to a unidirectional current. Impressively, the rectennas, because of their extremely small and fast tunnel diodes, are capable of converting solar radiation in the infrared region through the extremely fast and short wavelengths of visible light - something that has never been accomplished before. Silicon solar panels, by comparison, have a single band gap which, loosely speaking, allows the panel to convert electromagnetic radiation efficiently at only one small portion of the solar spectrum. The rectenna devices don't rely on a band gap and may be tuned to harvest light over the whole solar spectrum, creating maximum efficiency. Through atomic layer deposition, Willis has shown he is able to precisely coat the tip of the rectenna with layers of individual copper atoms until a gap of about 1.5 nanometers is achieved. The process is self-limiting and stops at 1.5 nanometer separation The size of the gap is critical because it creates an ultra-fast tunnel junction between the rectenna's two electrodes, allowing a maximum transfer of electricity. The nanosized gap gives energized electrons on the rectenna just enough time to tunnel to the opposite electrode before their electrical current reverses and they try to go back. The triangular tip of the rectenna makes it hard for the electrons to reverse direction, thus capturing the energy and rectifying it to a unidirectional current. Impressively, the rectennas, because of th

just another fuel cell?the vid is interesting

sorry, geek central. in case anyone is interested in some new energy efficient pc components. they do energy use/time measurements under load. Unfortunately they don't seem to take idle consumption into account

The measured energy imbalance of Earth

Self-organizing equipment could cut energy bills.

interesting new agency for renewable energy .... (view from Eurosolar)

energy consumption meter that integrates with google powermeter. bottom-up smart grid?

Mitsubishi Heavy Industries said Friday that it has succeeded in transmitting 10 kW of power through 500 m. An announcement that comes just after JAXA scientists reported one more breakthrough in the quest for Space Solar Power Systems (http://phys.org/news/2015-03-japan-space-scientists-wireless-energy.html). One step closer to Power Generation from Space/

from the press release (https://www.mhi-global.com/news/story/1503121879.html) "10 kilowatts (kW) of power was sent from a transmitting unit by microwave. The reception of power was confirmed at a receiver unit located at a distance of 500 meters (m) away by the illumination of LED lights, using part of power transmitted". So 10kW of transmission to light a few efficient LED lights??? In a 2011 report (https://www.mhi-global.com/company/technology/review/pdf/e484/e484017.pdf), MHI estimated this would generate the same electricity output as a 400-megawatt thermal plant - or enough to serve more than 150,000 homes during peak hours. The price? The same as publicly supplied power, according to its calculations. There are no results to boost these claims however. The main work they do now is focused on beam steering control. I guess the real application in mind is more targeted to terrestrial applications, eg wireless highway charging (http://www.bbc.com/future/story/20120312-wireless-highway-to-charge-cars). With the distances so much shorter, leading to much smaller antenna's and rectenna's this makes much more sense to me to develop.

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.

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."

Plants have many valuable functions: They provide food and fuel, release the oxygen that we breathe, and add beauty to our surroundings. Now, researchers wants to make plants even more useful by augmenting them with nanomaterials that could enhance their energy production and give them completely new functions, such as monitoring environmental pollutants.

Despite 50 years of research on high-power microwaves, the us military has yet to produce a usable weapon.

looks like some backwind for all the cold fusion believers ...

I just answered something very similar to Franco, except the conclusions: I don't think that there is a good reason for us or anybody else in ESA to get involved at this stage.

I agree - if this device would work it there would be other interest groups (like the energy sector) with a much more concrete stake in the technology.

"Her goal was to design and synthesise a super capacitor with increased energy density while maintaining power density and long cycle life. She designed, synthesised and characterised a novel core-shell nanorod electrode with hydrogemated TiO2(H-TiO2) core and polyaniline shell. H-TiO2 acts as the double layer electrostatic core. Good conductivity of H-TiO2 combined with the high pseudo capacitance of polyaniline results in significantly higher overall capacitance and energy density while retaining good power density and cycle life. This new electrode was fabricated into a flexible solid-state device to light an LED to test it in a practical application. Khare then evaluated the structural and electrochemical properties of the new electrode. It demonstrated high capacitance of 203.3 mF/cm2 (238.5 F/g) compared to the next best alternative super capacitor in previous research of 80 F/g, due to the design of the core-shell structure. This resulted in excellent energy density of 20.1 Wh/kg, comparable to batteries, while maintaining a high power density of 20540 W/kg. It also demonstrated a much higher cycle life compared to batteries, with a low 32.5% capacitance loss over 10,000 cycles at a high scan rate of 200 mV/s."

Comprehensive report on beamed energy propulsion

whatever you want to know about bep you will find it somewhere at these 650 pages.

A simple cube open at the top can increase the annual energy density generation by a factor (depending on the latitude) of 2 - 3.8 compared to a flat horizontal panel, versus an increase by a factor of 1.3 - 1.8 achieved from a flat panel using dual-axis tracking. Genetic algorithm are used to optimize the energy production in a day for arbitrarily shaped 3D solar cells confined to a given area footprint and total volume doi:10.1063/1.3308490 could be interesting to investigate