What is the $/kWh of industrial supercaps right now? The article you linked above had some projected numbers from startup companies, one of which seems to have gone under and the other of which is still in startup mode. I just helped put together an experimental off-grid PV system with 3kWh lead acid capacity at somewhere from $200-$250/kWh storage cost.
Is there anywhere a hobbyist or researcher could buy a few kWh of indsutrial supercaps?
Umm, this is how government funded R&D is supposed to work. The government spends money on projects that are too risky or too long-term for private companies to easily justify funding on internal dollars. Then when a higher level of technical maturity is reached private companies can take the body of knowledge, develop their own products for the government and private users, and start selling products to the government (and other customers) for less money than the government would have spent to build to develop and build it themselves (or pay a contractor to do for them). It's a win win win: the company wins, the government wins, and non-government customers win because they can now buy tech that up until then was controlled by the government.
It has happened in all sorts of fields including space. Government science and R&D funding has helped advance a huge number of fields.
But the government and many of the external researchers it funds are not in the business of making and selling products, so the plan for "technology transfer" and "transition" (to industry, whether real industry or the "prime" contractor industry) can be an important consideration in receiving govt dollars for a project depending on the work and technical readiness.
The world of manufacturing is faster and more flexible than ever because of cheap human labor in Chinese factory.
Need to have your factory assemble a new phone? You can train human employees in a day.
Maybe your supplier ran out of LCD screens, so you buy an order from another supplier but it comes loaded differently into a differently size box, or maybe it has a different connector. Time to call in your robot consultant to reprogram the purpose-built industrial bot so it can handle this new form factor. Oh wait, you have human labor? Just show him how to do it slightly differently and away you go.
If you had read the articles you would see that this robot is designed to be quickly configured to perform new tasks with a minimum of technical skills required. There will obviously still be a role for purpose-built bots that have better economy of scale, as that will be cheaper for extremely high quantity long production runs. A lot of manufacturing is meant to be fast and flexible with production or assembly lines being set up in days rather than weeks/months, maybe to handle the initial burst of demand as a new product is launched, then set up to produce a new product a month later. This robot is designed to enable US labor to compete with cheap Chinese labor in the world of fast and flexible manufacturing with less of a cost bump for the US product.
Even though oil does seep into the ocean naturally in some locations, human-caused oil spills are still bad news. Life will find a way, eventually, but in the meantime there is significant damage to the local ecosystem which was caused by humans, and resulting damage to human livelihoods. Even if you don't care about the ecological damage for its own sake do you not sympathize with the damage to human livelihoods?
To compare it to another scenario: floods sometimes happen naturally, but are sometimes caused by dams bursting, maybe due to human negligence. Does the fact that it can happen naturally make it okay if a burst dam destroys a town?
Is it actually common for TA's to deliver lectures? At my school professors are not allowed to require their TAs to lecture - any professor who made a habit of it would find themselves in hot water from the labor union. Maybe it's different at other schools.
Sometimes grad students can teach courses as a lecturer but it's difficult to get approval for this, and it is a higher pay grade than TA because it's more work and skill. Introductory language courses are often taught by grad students, usually with one professor creating the lesson plan, teaching one class, and supervising a number of grad student instructors who teach the remaining classes in a given semester.
53?!? And 6-8 weeks of PTO? WOW. Talk to any IT Developer, 50-100 hours per week. Average, easily 60. I was in Accounting & Auditing and averaged 55 hours (60+ for month, quarter, & annual closes). In IT, averaged 55; 100+ for deadlines. As an IT PM, 50-70 hours. 15-20 days PTO + 10 holidays.
And no, that does not count the hours spent on further education, certifications, and air travel for clients. And in the consulting world, not seeing home Monday to Thursday. Yes, our salaries are higher, 50k starting and growing to 80k+ over 5+ years, but considering the hours, I think comparable to teachers.
Just because you personally and possibly your industry are overworked doesn't mean you should belittle how hard teachers work. Why are you putting in so many hours anyway? In a school the (good) teachers put in extra time out of the love of teaching and their desire to see their students succeed and the teachers are overworked because there's not enough money to hire extra teachers.
Is IT really an important enough job to be putting in 100 hours per week? That's 14 hours/day 7 days/week during crunch time!! Are you at least getting OT or ST for those extra hours? You might be doing it out of love for your job but your manager and company are doing it because they love you putting in ~1.5 people's worth of work for 1 person's pay.
Minewolf machines do support remote control operation, which is clearly stated on the Minewolf website. The operator cabs are also armored and physically removed from the tiller where mines will generally explode and they are specified up to a particular blast size.
You want a nurse doing it, not a doctor. Doctors are usually too busy to do most of the injections they prescribe, and they're not the ones in clinics around flu season. For the best injection you want somebody who has experience, that's generally the nurse. A good one is so fast, precise, and good at distracting you that you might not even realize when they did it.
With an experienced administrator injections are not too bad, just a very brief very small prick, though they injection site can ache a bit for several hours sometimes.
Anyway, you have probably worked up this fear of injections over and over in your head to the point that you remember it as worse than it is. I'm also a bit nervous about getting injections, but I always go anyway and it's never as bad as I think it's going to be. Try getting one around flu season just to see what all of the fuss is about. When you make the appointment or show up at the clinic let them know that you're uncomfortable about injections and ask for the best person they have to do it - unless they're in a bad mood or super busy they'll help you out. And remember to relax, tense muscles will make it hurt more.
Range is a problem with THz partly because of the atmospheric loss but also in large part because the achievable transmit powers are so low. The benefit of THz is that it can penetrate things like dust, good for radar imaging in the desert, and it can also penetrate clothing, good for imaging you in the airport;)
What DARPA is building now is not going to be a field-ready unit, it will be a demonstration piece that pushes the state of the art forward to inform future work in the area.
The purpose of the DARPA program is to build a SAR, this LNA will likely be the frontend. There already exist diode mixers which can coherently downconvert 850GHz but the noise figure is bad. With this LNA at the frontend they should be able to mix it down with existing diode mixers or with fancier mixers without too much trouble.
I'm wondering of course how they'll be getting their transmit power - power at 850GHz does not come cheaply.
Nope, DARPA press release clearly states "gain at 0.85THz". The purpose of this program is to push ahead the maximum frequency to enable terahertz radar, so they're shooting for frequency more than GBP.
Anyway, GBP's of over 1THz have already been achieved in the fiber optic communication arena but at frequencies up to ~50GHz, not 850GHz.
You're incorrect sir. The Slashdot summary misquotes the linked DARPA press release which clearly states "gain at 0.85THz".
Gain-bandwidth product is mostly used for opamps because a given opamp could be put into an amplifier circuit with negative feedback which is either low gain and high bandwidth, or high gain and low bandwidth, and each circuit would have the same gain bandwidth product. For microwave/mm-wave amplifiers where 10dB of gain might be a luxury and most circuits don't make use of negative feedback it doesn't make nearly as much sense to discuss GBP.
The exciting part of this circuit is that it works at all at 0.85THz. The gain is probably very low which is why they went with a huge 10-stage LNA. Transistor current gain cutoff frequencies are probably in the 1-2THz range so gain per stage is very small and throwing gain away with negative feedback would not make sense here.
The summary and linked press releases are light on details so here is what I gleaned from the photograph of the chip based on some experience in the area of microwave/mm-wave device and circuit work. There will probably be much more technical information in upcoming papers in the research literature.
Based on the photo of the chip on the linked DARPA page this is not a receiver, but a low-noise amplifier (LNA) which would be used as the front-end for an imaging sensor or communications/radar receiver. It would be straightforward to turn this into an imaging detector at this point by adding a detector after the LNA though I don't think this has one. For a synthetic aperture radar more circuits will be required, especially a mixer to downconvert the frequency.
The slashdot summary misquotes the article saying that the circuit has "gain of 0.85 THz" but should say "gain at 0.85 THz". The LNA appears to have 10 amplifications stages which is very large for a LNA, which suggests that the gain per stage is still quite low at 0.85THz. This is to be expected as the best per-transistor gain cutoff frequencies are not too far 1THz that I'm aware of. The circuit also appears to be built in coplanar waveguide (a metallized signal strip in the middle surrounded by two ground strips) which is easy to fabricate and good for a research environment but it has a higher loss than microstrip (a signal line above a ground plane).
It's a SiC MESFET with graphene gate. It's interesting in that the SiC is the source of C for the graphene, and they use two different growth methods to form a schottky barrier contact for the gate and an ohmic contact for the source and drain. But that's all the graphene is doing is making contacts. Maybe these are really good contacts, but it will still be limited in performance in terms of the gate length and SiC channel material parameters, which are actually pretty good but it's not a graphene transistor at all.
These hype articles about Graphene fail to mention that conventional highly scaled CMOS processes have cutoff frequencies in the 100's of GHz already, but that's not a metric that relates well to the clock speed of a large digital chip, although it helps. Other very important factors include how tightly you can pack things, getting low-resistance low-capacitance interconnet, and managing FET to FET variability over millions/billions of transistors. These latter factors have a bigger impact on clock speed than the transistors themselves.
I haven't read much of the latest on graphene transistors but the last ones I saw didn't come close to state of the art silicon, and their off-state current is very high because of the bandgap issue. You can make a bandgap in various ways such as sandwiching the graphene in various materials or making it into small strips but these tend to reduce the high mobility that made graphene so fascinating. I'm sure we'll see some interesting stuff come out of it but most of the press on graphene is the hype that researchers have to do to get funding.
Resonance isn't necessarily involved and certainly isn't required. Given that they will want a brief but high energy electrical pulse they much more likely are using a Marx Generator than any type of resonant transformer (e.g. Tesla Coil). This is supported by the fact that Marx Generators are one of Applied Energetics specialties. Otherwise it may simply be a single pulse cap possible with PFN or pulse transformer.
If you've got steel studs or steel nails you can just use a small neodymium magnet from your fridge. Run it along the wall until you feel the pull, if the walls are sufficiently thin then it will even stick directly to the studs. Heck, you can even just knock on the wall to feel and listen for where the studs are. It's harder than with a nice stud finder obviously but for the occasional hanging it's fine. If you really want a stud finder you could also ask around your friends to borrow one, ask your neighbors, your apartment manager, or make a post on Craigslist or Freecycle.
Sure a rental service for such things would be nice (assuming it's even profitable at a price people are willing to pay), but it's lazy on your part to not explore your many and varied legitimate options.
Commercial versus non-commercial is about a company building a standard product which the government utilizes through firm fixed price contracts. SpaceX has a published price for a launch, and that's exactly what they charge. In contrast the traditional NASA approach has been to award cost plus contracts to major contractors and an army of subcontractors and NASA is more of a partner than a customer, building a one-off custom design. In this type of system cost overruns often get billed to the customer (NASA), but with firm fixed price the work is expected to be completed for the agreed upon price and SpaceX has stated that any cost overruns on their NASA programs above the fixed price launch costs will be covered by SpaceX, not NASA.
Contract vehicles notwithstanding, it also appears that even in NASA's opinion SpaceX is simply more efficient at getting things done than the usual NASA & defense contractor method probably due to reduced management and organizational overhead: http://www.nasa.gov/pdf/586023main_8-3-11_NAFCOM.pdf
A big part of SpaceX's efficiency is that they are vertically integrated, doing most of the work themselves. With the non-commercial cost-plus model Congress had the ability to split up subcontracts for the shuttle development and manufacturing across the entire nation, with drastic hits to efficiency.
Although it may not seem like a totally commercial enterprise with NASA as the major source of SpaceX's revenue (for now), but there are important changes taking place in how NASA is acquiring launch capacity which seem like they have the capability to reduce costs over the past model
Field emission is indeed a tunneling process. Old vacuum tubes used thermionic emission - as the cathode is heated some of the electrons have enough energy/speed to escape the potential barrier that ordinarily exists between the cathode and the vacuum. At room temperature essentially none of the electrons have enough energy to be above that potential energy barrier. When the bias voltage is applied it must decrease the potential energy past the barrier which will make the barrier thinner. With enough voltage the barrier is thin enough to tunnel through.
To use a gravity and beach ball analogy: Think of the electrons as beach balls confined to a canyon, they are bouncing around a bit because they're not at absolute zero temperature, but they're not going anywhere. With thermionic emission, heating it up is like blowing a big fan at them which gets them bouncing around at much higher speed - so much so that some of them bounce right out over the top of the canyon. For field emission, with an applied electric field you are decreasing potential energy on the other side of the canyon wall. Since I'm using a gravity analogy, that's like digging out the other side of the canyon past the canyon wall, which thins the canyon wall until some of the beach balls can break right through it. In either case in this analogy, once they're out of the canyon the electric field is like a downward slope, and they just roll down the hill to the anode.
Seems a bit redundant really, I mean everything is moving over the next two decades to electric anyway.
Until we see new power plants being built I am not so sure we will have a large scale transition to electrically powered vehicles. Various parts of our electrical grid are already pretty stressed out and seeing periodic brown outs and black outs. This could put a damper on large scale adoption of electric vehicles.
Very doom and gloom! Converting all vehicles (not just cars) to full electric will require about a 50% increase in electricity generation, on average. This will be spread over several decades because the gasoline and diesel engines are hardly going to disappear overnight, so the rate of upgrade is well within our capabilities.
The bigger challenge is dealing with the load transients of fast charging stations. The ideal way to charge vehicles in terms of battery lifetime and grid impact is overnight, which will make use of cheap base load energy, and slower charging is better for the battery. But there will be a need for fast charging during the day, and some upgrades to the grid will be required as it becomes more common. Charging stations may need to make use of local energy storage to supply the transient demand for high charging powers without overstressing their grid connections. As charging becomes more common, charging stations will be equipped with beefier connections to mitigate the need for local energy storage, and smart load management can even out the grid demand at a single charging station, and even across multiple charging stations in a regional area to ensure that the grid capacity is not overloaded.
So on short, yes the electrical infrastructure will require upgrades. But supply follows demand, and as demand for electricity rises so will the supply. Some areas that have overstressed grids will not be able to add many fast-charge stations, or they might have time of day restrictions or higher prices for their electricity. But there's plenty of capacity at night, and people can easily charge their cars then.
Slew is somewhat correct. The nonpolar/semipolar substrates are currently very expensive and small (1 sq. inch at best, compared to 12sq. inches for sapphire substrates that all commercial LED's, except Soraa's, are currently grown on)..
I thought commercial LEDs had moved on to SiC substrates for the higher thermal conductivity, even though they're more expensive than sapphire. Most commercial GaN RF circuits and transistors (including Cree) moved on from sapphire a while ago are fabricated on SiC substrates, and a couple companies are doing GaN circuits on silicon substrates. I thought that Cree for sure would be growing their LED's on SiC given that they're the world's main source of SiC substrates, and based on their webpage that seems to be the case.
Go read your source a little more carefully, including the linked interview with the original reporter. When Bill Nye criticized literal interpretation of the Bible, there were a few people who left upset, but it was apparently very low key, no booing, no "bastion" of people storming out or making a scene, and Bill Nye's lecture was uninterrupted and Bill may not have even realized the reaction of these few people.
Sure I'd like to live in a world where all religious people accept that the Bible should not be taken literally, but you (like many according to the followups in your source) appear to have greatly overstated the negative reaction at Bill Nye's lecture by repeating the inflammatory punch line without reading any deeper.
Either someone is intentionally lying here (remember, these people are psychologists and know how to do it)
Are you serious? Your sophisticated analysis is based on the assumption that psychologists are manipulative liars? Is there anything you feel you need to have a basis for stating, or do you just fabricate (or repeat) propaganda and string it together as needed?
It's based on the fact that many researchers, or at least people reporting research to the media, will play games with statistics to make new research seem more effective or revolutionary than they already are. The concern that GP brings up is not trivial - it is a serious flaw not to have stated that in the relative completion rates of the two treatment methods in the article because this is a very easy way to mislead readers about the results. The researchers did address this is their paper, but as usual the article in the Slashdot summary was poorly written.
Even if you use a power buffer like a huge capacitor bank to store the amount of energy needed to recharge a vehicle like a Tesla Roadster (which has roughly the quoted 500 mile range suggested in the original article) in a short period of time, that capacitor bank will need to be recharged in roughly a similar amount of time... with a power load for a heavily used recharging station to be roughly equivalent to this device I was using in San Francisco. I could easily see such a filling station be in the MegaWatt range for power consumption. In other words the overall electrical transmission infrastructure to get a whole series of stations like this built would require a substantial construction effort just to get those power transmission lines put to all of those station.
Large discontinuous loads can be difficult for utilities to supply, but if charging stations charge up capacitors or some other local energy storage to be used to supply to high peak load of fast battery charging then the utility can easily supply the load, because utilities like steady loads. There will be an increase in average power delivered, and the load may have a somewhat higher peak to average ratio, but let's look at the increase in average power: Total vehicular energy usage from petroleum (including boats, planes, shipping, etc.) is on the order of 25% of US energy consumption, electricity accounts for about 40% of energy usage (source LLNL 2010 based on EIA data). If we convert all cars to electricity that's maybe a 50% total increase in electricity usage. Big, but not game changing. And the increase will be gradual, not instant.
Smart grid concepts are another option to present a more continuous load to a grid circuit by ensuring that the number of cars charging on a given circuit is relatively constant, and this can be spread out over many charging stations across a city. Those who are in a hurry can pay a slight premium to charge immediately, and those in no rush can take advantage of cheaper rates. It's much like discounts currently available for those who use less power at peak times.
So do you like a future with high voltage power lines being built in your backyard? That is the future you are asking for here, where those become a much more common sight in almost everybody's neighborhood. The grid impact of these stations is going to be enormous with any kind of electric vehicle future.
That's hilarious, your dystopian future is one where we have a few more power lines! As I said we're looking at order of 50% increase in electricity usage to accommodate electric vehicles. They're not going to have to run HV transmission lines in people's backyards to make this work, they'll take the existing power infrastructure and upgrade it - increase voltage, add more circuits in parallel. Even if they build dedicated circuits to every fast-charge station you won't see much of it because it's going to be focused in commercial areas and near highways where gas stations are. Who cares if there's a new power line next to the highway? Actually, who cares if there's a new one in your backyard? There's a power line I can see from my backyard and I don't care.
The fossil fuel gravy train is leaving the station, and sooner or later you'll need to get on board with the alternatives, even if it means *shudder* more electrical power lines.
Slashdot Mirror
What is the $/kWh of industrial supercaps right now? The article you linked above had some projected numbers from startup companies, one of which seems to have gone under and the other of which is still in startup mode. I just helped put together an experimental off-grid PV system with 3kWh lead acid capacity at somewhere from $200-$250/kWh storage cost.
Is there anywhere a hobbyist or researcher could buy a few kWh of indsutrial supercaps?
Umm, this is how government funded R&D is supposed to work. The government spends money on projects that are too risky or too long-term for private companies to easily justify funding on internal dollars. Then when a higher level of technical maturity is reached private companies can take the body of knowledge, develop their own products for the government and private users, and start selling products to the government (and other customers) for less money than the government would have spent to build to develop and build it themselves (or pay a contractor to do for them). It's a win win win: the company wins, the government wins, and non-government customers win because they can now buy tech that up until then was controlled by the government.
It has happened in all sorts of fields including space. Government science and R&D funding has helped advance a huge number of fields.
But the government and many of the external researchers it funds are not in the business of making and selling products, so the plan for "technology transfer" and "transition" (to industry, whether real industry or the "prime" contractor industry) can be an important consideration in receiving govt dollars for a project depending on the work and technical readiness.
The world of manufacturing is faster and more flexible than ever because of cheap human labor in Chinese factory.
Need to have your factory assemble a new phone? You can train human employees in a day.
Maybe your supplier ran out of LCD screens, so you buy an order from another supplier but it comes loaded differently into a differently size box, or maybe it has a different connector. Time to call in your robot consultant to reprogram the purpose-built industrial bot so it can handle this new form factor. Oh wait, you have human labor? Just show him how to do it slightly differently and away you go.
If you had read the articles you would see that this robot is designed to be quickly configured to perform new tasks with a minimum of technical skills required. There will obviously still be a role for purpose-built bots that have better economy of scale, as that will be cheaper for extremely high quantity long production runs. A lot of manufacturing is meant to be fast and flexible with production or assembly lines being set up in days rather than weeks/months, maybe to handle the initial burst of demand as a new product is launched, then set up to produce a new product a month later. This robot is designed to enable US labor to compete with cheap Chinese labor in the world of fast and flexible manufacturing with less of a cost bump for the US product.
Even though oil does seep into the ocean naturally in some locations, human-caused oil spills are still bad news. Life will find a way, eventually, but in the meantime there is significant damage to the local ecosystem which was caused by humans, and resulting damage to human livelihoods. Even if you don't care about the ecological damage for its own sake do you not sympathize with the damage to human livelihoods?
To compare it to another scenario: floods sometimes happen naturally, but are sometimes caused by dams bursting, maybe due to human negligence. Does the fact that it can happen naturally make it okay if a burst dam destroys a town?
Is it actually common for TA's to deliver lectures? At my school professors are not allowed to require their TAs to lecture - any professor who made a habit of it would find themselves in hot water from the labor union. Maybe it's different at other schools.
Sometimes grad students can teach courses as a lecturer but it's difficult to get approval for this, and it is a higher pay grade than TA because it's more work and skill. Introductory language courses are often taught by grad students, usually with one professor creating the lesson plan, teaching one class, and supervising a number of grad student instructors who teach the remaining classes in a given semester.
Longest hours? Google: http://www.washingtonpost.com/blogs/answer-sheet/post/survey-teachers-work-53-hours-per-week-on-average/2012/03/16/gIQAqGxYGS_blog.html
53?!? And 6-8 weeks of PTO? WOW. Talk to any IT Developer, 50-100 hours per week. Average, easily 60. I was in Accounting & Auditing and averaged 55 hours (60+ for month, quarter, & annual closes). In IT, averaged 55; 100+ for deadlines. As an IT PM, 50-70 hours. 15-20 days PTO + 10 holidays.
And no, that does not count the hours spent on further education, certifications, and air travel for clients. And in the consulting world, not seeing home Monday to Thursday. Yes, our salaries are higher, 50k starting and growing to 80k+ over 5+ years, but considering the hours, I think comparable to teachers.
Just because you personally and possibly your industry are overworked doesn't mean you should belittle how hard teachers work. Why are you putting in so many hours anyway? In a school the (good) teachers put in extra time out of the love of teaching and their desire to see their students succeed and the teachers are overworked because there's not enough money to hire extra teachers.
Is IT really an important enough job to be putting in 100 hours per week? That's 14 hours/day 7 days/week during crunch time!! Are you at least getting OT or ST for those extra hours? You might be doing it out of love for your job but your manager and company are doing it because they love you putting in ~1.5 people's worth of work for 1 person's pay.
Minewolf machines do support remote control operation, which is clearly stated on the Minewolf website. The operator cabs are also armored and physically removed from the tiller where mines will generally explode and they are specified up to a particular blast size.
You want a nurse doing it, not a doctor. Doctors are usually too busy to do most of the injections they prescribe, and they're not the ones in clinics around flu season. For the best injection you want somebody who has experience, that's generally the nurse. A good one is so fast, precise, and good at distracting you that you might not even realize when they did it.
With an experienced administrator injections are not too bad, just a very brief very small prick, though they injection site can ache a bit for several hours sometimes.
Anyway, you have probably worked up this fear of injections over and over in your head to the point that you remember it as worse than it is. I'm also a bit nervous about getting injections, but I always go anyway and it's never as bad as I think it's going to be. Try getting one around flu season just to see what all of the fuss is about. When you make the appointment or show up at the clinic let them know that you're uncomfortable about injections and ask for the best person they have to do it - unless they're in a bad mood or super busy they'll help you out. And remember to relax, tense muscles will make it hurt more.
Range is a problem with THz partly because of the atmospheric loss but also in large part because the achievable transmit powers are so low. The benefit of THz is that it can penetrate things like dust, good for radar imaging in the desert, and it can also penetrate clothing, good for imaging you in the airport ;)
What DARPA is building now is not going to be a field-ready unit, it will be a demonstration piece that pushes the state of the art forward to inform future work in the area.
The purpose of the DARPA program is to build a SAR, this LNA will likely be the frontend. There already exist diode mixers which can coherently downconvert 850GHz but the noise figure is bad. With this LNA at the frontend they should be able to mix it down with existing diode mixers or with fancier mixers without too much trouble.
I'm wondering of course how they'll be getting their transmit power - power at 850GHz does not come cheaply.
Nope, DARPA press release clearly states "gain at 0.85THz". The purpose of this program is to push ahead the maximum frequency to enable terahertz radar, so they're shooting for frequency more than GBP.
Anyway, GBP's of over 1THz have already been achieved in the fiber optic communication arena but at frequencies up to ~50GHz, not 850GHz.
You're incorrect sir. The Slashdot summary misquotes the linked DARPA press release which clearly states "gain at 0.85THz".
Gain-bandwidth product is mostly used for opamps because a given opamp could be put into an amplifier circuit with negative feedback which is either low gain and high bandwidth, or high gain and low bandwidth, and each circuit would have the same gain bandwidth product. For microwave/mm-wave amplifiers where 10dB of gain might be a luxury and most circuits don't make use of negative feedback it doesn't make nearly as much sense to discuss GBP.
The exciting part of this circuit is that it works at all at 0.85THz. The gain is probably very low which is why they went with a huge 10-stage LNA. Transistor current gain cutoff frequencies are probably in the 1-2THz range so gain per stage is very small and throwing gain away with negative feedback would not make sense here.
The summary and linked press releases are light on details so here is what I gleaned from the photograph of the chip based on some experience in the area of microwave/mm-wave device and circuit work. There will probably be much more technical information in upcoming papers in the research literature.
Based on the photo of the chip on the linked DARPA page this is not a receiver, but a low-noise amplifier (LNA) which would be used as the front-end for an imaging sensor or communications/radar receiver. It would be straightforward to turn this into an imaging detector at this point by adding a detector after the LNA though I don't think this has one. For a synthetic aperture radar more circuits will be required, especially a mixer to downconvert the frequency.
The slashdot summary misquotes the article saying that the circuit has "gain of 0.85 THz" but should say "gain at 0.85 THz". The LNA appears to have 10 amplifications stages which is very large for a LNA, which suggests that the gain per stage is still quite low at 0.85THz. This is to be expected as the best per-transistor gain cutoff frequencies are not too far 1THz that I'm aware of. The circuit also appears to be built in coplanar waveguide (a metallized signal strip in the middle surrounded by two ground strips) which is easy to fabricate and good for a research environment but it has a higher loss than microstrip (a signal line above a ground plane).
Anyway that's my 2 cents.
It's a SiC MESFET with graphene gate. It's interesting in that the SiC is the source of C for the graphene, and they use two different growth methods to form a schottky barrier contact for the gate and an ohmic contact for the source and drain. But that's all the graphene is doing is making contacts. Maybe these are really good contacts, but it will still be limited in performance in terms of the gate length and SiC channel material parameters, which are actually pretty good but it's not a graphene transistor at all.
These hype articles about Graphene fail to mention that conventional highly scaled CMOS processes have cutoff frequencies in the 100's of GHz already, but that's not a metric that relates well to the clock speed of a large digital chip, although it helps. Other very important factors include how tightly you can pack things, getting low-resistance low-capacitance interconnet, and managing FET to FET variability over millions/billions of transistors. These latter factors have a bigger impact on clock speed than the transistors themselves.
I haven't read much of the latest on graphene transistors but the last ones I saw didn't come close to state of the art silicon, and their off-state current is very high because of the bandgap issue. You can make a bandgap in various ways such as sandwiching the graphene in various materials or making it into small strips but these tend to reduce the high mobility that made graphene so fascinating. I'm sure we'll see some interesting stuff come out of it but most of the press on graphene is the hype that researchers have to do to get funding.
Resonance isn't necessarily involved and certainly isn't required. Given that they will want a brief but high energy electrical pulse they much more likely are using a Marx Generator than any type of resonant transformer (e.g. Tesla Coil). This is supported by the fact that Marx Generators are one of Applied Energetics specialties. Otherwise it may simply be a single pulse cap possible with PFN or pulse transformer.
If you've got steel studs or steel nails you can just use a small neodymium magnet from your fridge. Run it along the wall until you feel the pull, if the walls are sufficiently thin then it will even stick directly to the studs. Heck, you can even just knock on the wall to feel and listen for where the studs are. It's harder than with a nice stud finder obviously but for the occasional hanging it's fine. If you really want a stud finder you could also ask around your friends to borrow one, ask your neighbors, your apartment manager, or make a post on Craigslist or Freecycle.
Sure a rental service for such things would be nice (assuming it's even profitable at a price people are willing to pay), but it's lazy on your part to not explore your many and varied legitimate options.
Do you think spammers scraping the web for email addresses respect robots.txt?
Commercial versus non-commercial is about a company building a standard product which the government utilizes through firm fixed price contracts. SpaceX has a published price for a launch, and that's exactly what they charge. In contrast the traditional NASA approach has been to award cost plus contracts to major contractors and an army of subcontractors and NASA is more of a partner than a customer, building a one-off custom design. In this type of system cost overruns often get billed to the customer (NASA), but with firm fixed price the work is expected to be completed for the agreed upon price and SpaceX has stated that any cost overruns on their NASA programs above the fixed price launch costs will be covered by SpaceX, not NASA.
Contract vehicles notwithstanding, it also appears that even in NASA's opinion SpaceX is simply more efficient at getting things done than the usual NASA & defense contractor method probably due to reduced management and organizational overhead: http://www.nasa.gov/pdf/586023main_8-3-11_NAFCOM.pdf
A big part of SpaceX's efficiency is that they are vertically integrated, doing most of the work themselves. With the non-commercial cost-plus model Congress had the ability to split up subcontracts for the shuttle development and manufacturing across the entire nation, with drastic hits to efficiency.
Although it may not seem like a totally commercial enterprise with NASA as the major source of SpaceX's revenue (for now), but there are important changes taking place in how NASA is acquiring launch capacity which seem like they have the capability to reduce costs over the past model
Field emission is indeed a tunneling process. Old vacuum tubes used thermionic emission - as the cathode is heated some of the electrons have enough energy/speed to escape the potential barrier that ordinarily exists between the cathode and the vacuum. At room temperature essentially none of the electrons have enough energy to be above that potential energy barrier. When the bias voltage is applied it must decrease the potential energy past the barrier which will make the barrier thinner. With enough voltage the barrier is thin enough to tunnel through.
To use a gravity and beach ball analogy: Think of the electrons as beach balls confined to a canyon, they are bouncing around a bit because they're not at absolute zero temperature, but they're not going anywhere. With thermionic emission, heating it up is like blowing a big fan at them which gets them bouncing around at much higher speed - so much so that some of them bounce right out over the top of the canyon. For field emission, with an applied electric field you are decreasing potential energy on the other side of the canyon wall. Since I'm using a gravity analogy, that's like digging out the other side of the canyon past the canyon wall, which thins the canyon wall until some of the beach balls can break right through it. In either case in this analogy, once they're out of the canyon the electric field is like a downward slope, and they just roll down the hill to the anode.
Seems a bit redundant really, I mean everything is moving over the next two decades to electric anyway.
Until we see new power plants being built I am not so sure we will have a large scale transition to electrically powered vehicles. Various parts of our electrical grid are already pretty stressed out and seeing periodic brown outs and black outs. This could put a damper on large scale adoption of electric vehicles.
Very doom and gloom! Converting all vehicles (not just cars) to full electric will require about a 50% increase in electricity generation, on average. This will be spread over several decades because the gasoline and diesel engines are hardly going to disappear overnight, so the rate of upgrade is well within our capabilities.
The bigger challenge is dealing with the load transients of fast charging stations. The ideal way to charge vehicles in terms of battery lifetime and grid impact is overnight, which will make use of cheap base load energy, and slower charging is better for the battery. But there will be a need for fast charging during the day, and some upgrades to the grid will be required as it becomes more common. Charging stations may need to make use of local energy storage to supply the transient demand for high charging powers without overstressing their grid connections. As charging becomes more common, charging stations will be equipped with beefier connections to mitigate the need for local energy storage, and smart load management can even out the grid demand at a single charging station, and even across multiple charging stations in a regional area to ensure that the grid capacity is not overloaded.
So on short, yes the electrical infrastructure will require upgrades. But supply follows demand, and as demand for electricity rises so will the supply. Some areas that have overstressed grids will not be able to add many fast-charge stations, or they might have time of day restrictions or higher prices for their electricity. But there's plenty of capacity at night, and people can easily charge their cars then.
Slew is somewhat correct. The nonpolar/semipolar substrates are currently very expensive and small (1 sq. inch at best, compared to 12sq. inches for sapphire substrates that all commercial LED's, except Soraa's, are currently grown on). .
I thought commercial LEDs had moved on to SiC substrates for the higher thermal conductivity, even though they're more expensive than sapphire. Most commercial GaN RF circuits and transistors (including Cree) moved on from sapphire a while ago are fabricated on SiC substrates, and a couple companies are doing GaN circuits on silicon substrates. I thought that Cree for sure would be growing their LED's on SiC given that they're the world's main source of SiC substrates, and based on their webpage that seems to be the case.
Go read your source a little more carefully, including the linked interview with the original reporter. When Bill Nye criticized literal interpretation of the Bible, there were a few people who left upset, but it was apparently very low key, no booing, no "bastion" of people storming out or making a scene, and Bill Nye's lecture was uninterrupted and Bill may not have even realized the reaction of these few people.
Sure I'd like to live in a world where all religious people accept that the Bible should not be taken literally, but you (like many according to the followups in your source) appear to have greatly overstated the negative reaction at Bill Nye's lecture by repeating the inflammatory punch line without reading any deeper.
Either someone is intentionally lying here (remember, these people are psychologists and know how to do it)
Are you serious? Your sophisticated analysis is based on the assumption that psychologists are manipulative liars? Is there anything you feel you need to have a basis for stating, or do you just fabricate (or repeat) propaganda and string it together as needed?
It's based on the fact that many researchers, or at least people reporting research to the media, will play games with statistics to make new research seem more effective or revolutionary than they already are. The concern that GP brings up is not trivial - it is a serious flaw not to have stated that in the relative completion rates of the two treatment methods in the article because this is a very easy way to mislead readers about the results. The researchers did address this is their paper, but as usual the article in the Slashdot summary was poorly written.
Large discontinuous loads can be difficult for utilities to supply, but if charging stations charge up capacitors or some other local energy storage to be used to supply to high peak load of fast battery charging then the utility can easily supply the load, because utilities like steady loads. There will be an increase in average power delivered, and the load may have a somewhat higher peak to average ratio, but let's look at the increase in average power: Total vehicular energy usage from petroleum (including boats, planes, shipping, etc.) is on the order of 25% of US energy consumption, electricity accounts for about 40% of energy usage (source LLNL 2010 based on EIA data). If we convert all cars to electricity that's maybe a 50% total increase in electricity usage. Big, but not game changing. And the increase will be gradual, not instant.
Smart grid concepts are another option to present a more continuous load to a grid circuit by ensuring that the number of cars charging on a given circuit is relatively constant, and this can be spread out over many charging stations across a city. Those who are in a hurry can pay a slight premium to charge immediately, and those in no rush can take advantage of cheaper rates. It's much like discounts currently available for those who use less power at peak times.
That's hilarious, your dystopian future is one where we have a few more power lines! As I said we're looking at order of 50% increase in electricity usage to accommodate electric vehicles. They're not going to have to run HV transmission lines in people's backyards to make this work, they'll take the existing power infrastructure and upgrade it - increase voltage, add more circuits in parallel. Even if they build dedicated circuits to every fast-charge station you won't see much of it because it's going to be focused in commercial areas and near highways where gas stations are. Who cares if there's a new power line next to the highway? Actually, who cares if there's a new one in your backyard? There's a power line I can see from my backyard and I don't care.
The fossil fuel gravy train is leaving the station, and sooner or later you'll need to get on board with the alternatives, even if it means *shudder* more electrical power lines.