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Nanoscale power plants |
Huge research efforts go into the development of nanoscale sensing devices for applications ranging from medical and biosensing to environmental monitoring to military use. In comparison, innovations for delivering nanoscale energy sources to power these devices are almost non-existent. The energy to be fed into a nano... |
"We have developed a direct-current nanogenerator that is driven by ultrasonic waves" Dr. Zhong Lin Wang explains to Nanowerk. "The basic principle is to use piezoelectric and semiconducting coupled nanowires, such as zinc oxide, to convert mechanical energy into electricity. This nanogenerator has the potential to dir... |
Wang, Regents' Professor, COE Distinguished Professor, and Director, Center for Nanostructure Characterization, at Georgia Tech, and his group have previously demonstrated the concept of a nanogenerator by deflecting aligned nanowires using a conductive atomic force microscopy (AFM) tip, and the output signal came from... |
"In order for this nanogenerator to have practical uses in real life applications, however, we had to come up with an innovative design to drastically improve its performance with regard to the following aspects" says Wang: "First, we must eliminate the use of an AFM for making the mechanical deformation of the nanowir... |
Wang's group has solved these problems using an innovative approach published in a recent issue of Science ("Direct-Current Nanogenerator Driven by Ultrasonic Waves"). |
Schematic of nanogenerator |
Schematic shows the direct current nanogenerator built using aligned ZnO nanowire arrays with a zigzag top electrode. The nanogenerator is driven by an external ultrasonic wave or mechanical vibration and the output current is continuous. (Image: Georgia Tech) |
In the most recent development, the Georgia Tech scientists now have made their nanogenerator work in biofluid and the performance has improved 30-fold compared to what they reported in the paper mentioned above. By generating electricity in liquid, this new report ("Integrated Nanogenerators in Biofluid") sets a platf... |
The ultrasonic wave transported through the fluid and triggered the vibration of the electrode and nanowires to generate electricity. The size of the nanogenerators used in these studies was about 2 mm2. There are more than one million nanowires in each of these generators. Wang and his team kept the ultrasonic wave on... |
The nanogenerators in this study also show the possibility of integrating multiple nanogenerators in biofluid for receiving high power output. This is a key step towards self-powering biosensing and medical applications. |
Going forward, Wang and the team will try to optimize the growth of the nanowire arrays in size and height uniformity and their distribution on substrate as well as the design of the top electrode, so that most of the nanowires will generate electricity. The second goal will be to raise the output voltage to more than ... |
Maybe it's time to read Isaac Asimov's Fantastic Voyage again... |
These articles might interest you as well: |
A Bilston Enamel Motto Box, Circa 1780-1810, the motto "Fear God Honor The King, Kiss a Pretty Girl, That's no Sin" a pale blue ribbed base, the mirror is original. |
Sunday, February 17, 2008 |
Analyzing the Juno-106 DCO circuit |
In the previous posting, we discussed how the core of a typical VCO works, and the main sources of drift and instability in a VCO core circuit. The Digitally Controlled Oscillator (DCO) is a 1980s technology designed to eliminate most or all of these sources of inaccuracy, while still operating as basically an analog V... |
The Roland Juno-106 is a well known synth that uses DCO circuits. Like the conventional VCO core discussed in the February 8 post, the Juno-106 DCO is a sawtooth-core oscillator, and it produces the sawtooth waveform by charging a capacitor at a constant rate. However, unlike the VCO, the discharge of the capacitor is ... |
This setup uncouples the capacitor charging rate from the desired output frequency; the integrating capacitor discharge is controlled by the timer and is independent of how charged the capacitor is. The 106's module board CPU figures out what starting value to set the timer to using the number of the note played (anot... |
However, it is still necessary to charge the cap at a rate that is proportional to the frequency; otherwise, the sawtooth will not maintain a constant amplitude as the frequency changes. (Consider the extreme case of a charging rate that does not vary at all with frequency. At low frequencies, the cap will have a long ... |
(A note here: My previous post on this topic to VSE was in error in stating that the Juno-106 DCO circuit uses a constant current circuit to charge the integrating capacitor. A closer examination of the schematic shows that it does not. Which leads us to our next topic...) |
When I examined the whole DCO control logic, I found something surprising. When the CPU is computing the digital count value to be loaded into the timer, and fed to the D/A converter to produce the control voltage, it takes into account the things you'd expect -- the note that was played, pitch bend, LFO, and portamen... |
• 4' range: 4 MHz |
• 8' range: 2 MHz |
• 16' range: 1 MHz |
The timers do not know what range is selected; rather, changing the range changes the speed at which the timers are clocked, to produce the various frequency ranges. The cap charging control voltage is compensated by selecting one of three current-limiting resistors according to the range setting. I did some math and... |
Operational characteristics of this circuit: The synth has a master tune knob on the back, and although it's fairly stable, it does need tuning now and then. What can drift to cause the need for a tuning knob? The only thing that can is the master clock. It's an uncompensated crystal oscillator, which can drift with... |
One other thing I note about the 106 DCO circuit is the difference in response to a rapidly varying control voltage. In an all-analog VCO circuit, when the control voltage changes, the circuit will "notice" immediately; the constant-current source will respond by changing the capacitor charging rate whenever the contro... |
The 106 provides three waveforms from the DCO: sawtooth, pulse, and a suboctave square wave. The sawtooth that you hear is the direct output from the DCO core. The pulse wave is derived from the sawtooth via a wave-shaping circuit. An interesting detail of this is that when the pulse is de-selected, there isn't a sw... |
RevoJak said... |
Wow this is great!!! Flip at world conspiracy let me borrow his juno 106 when I was 16..I'm 28 now.. I am actually looking for a new analog synth with juno or sh101 characteristics.. Currently I only have a future retro revolution that is the only true analog piece I have... Your dont have anything for sale do you? Gre... |
RevoJak said... |
please email me I live in |
Qwave said... |
Again a good and easy to understand text. Thanks ! |
But I found a little error: the schematics shown says: A/D converter left of the current limiting resistor. |
Benjamin Budts said... |
great somebody analyzes this and explain it. |
I wonder how the chorus works on these synths, that's what makes them popular nowadays, the fat sound (Never played one though). |
Wallstreet said... |
Nice post! Found this searching google. I think my crystal is producing an out of tune C these days... |
I had noticed the change in the DCO frequency with rapid CVs. You can tell it's a cycling when you hit the keys fast. Interesting to read about why that is happening. I thought I had yet another problem with my Juno. |
Prince.Cobra said... |
i hated the sound of my 106 in unison mode, and i wanted to do something about it. So i looked through the schematic and found that all the vca/vcf chips get routed to one op-amp. before the op-amp they use a simple mixer (a resistor of, if i recall it was 3megs for each output of the 6 voices) to combine the 6 voices ... |
So i de-soldered 5 of the resistors, and routed them to 5 switches out the back. So now the voices go out form the original simple mixer to switches then back through the resistor value then into the op-amp. |
Now when i play in unison mode i can choose how man voices i want on against the un-effected one.... any way it works great the other voices go to ground when switched off and now i have a bad ass Juno 106 mono synth. |
Redistricting in Need of Reform |
California Gov. Arnold Schwarzenegger used his recent State of the State address to criticize current redistricting practices and to recommend reform of the way congressional and state legislative districts are drawn following each census. |
Schwarzenegger's diagnosis of the problem is accurate even if his reform prescription is imperfect. |
The word election implies choice, competition and the possibility of both success and failure. Today, American representative government clearly suffers from the handicap of a serious lack of competition and meaningful choice. Those who hold political office enjoy tremendous, largely self-bestowed, advantages in electo... |
Unlike most democracies, we place the power to shape political districts in the hands of politicians rather than an independent commission. Redistricting has evolved into the electoral instrument that best serves to protect and strengthen incumbency advantage (search). Redistricting creates winners and losers and, in t... |
Schwarzenegger rightly bemoans the fact that last November not one of the 53 seats in California's congressional delegation, and not one of the state's 100 legislative seats, switched from Republican to Democrat or vice-versa. Nationally, the lack of electoral competition is staggering. |
In 2004, only 13 of 435 congressional seats changed from one party to another. The reelection rate for House incumbents was over 98 percent. Nine in 10 Americans live in districts where the outcome is so certain that their votes are irrelevant. Hence, Schwarzenegger's stinging retort, "What kind of a democracy is that?... |
This is not the outcome our constitutional framers intended. Article I outlines how the House is designed to be the legislative body most responsive to public opinion. According to The Federalist Papers (search), the House was viewed as a "numerous and changeable body" reflecting the shifting popular will. The decline ... |
There are no easy solutions to the redistricting mess. Nevertheless, removing politicians' control over redistricting can help to lessen the problem. Schwarzenegger's remedy takes away the power to draw state and congressional boundaries from politicians and gives it to an independent panel of retired judges. |
Placing judges rather than politicians in charge may improve the redistricting outcome but does not guarantee more elections that are competitive. Judges are inherently unpredictable creatures. Individually or collectively, they may tend to favor Republicans or Democrats, or neither party at all. |
Nevertheless, California's recent experience with judge-based redistricting was fairly positive. In 1991, following a political impasse, the judiciary was forced to redraw the state's legislative districts and generally produced more competitive districts than existed previously or since. |
There are other reform instruments that could also inject a modicum of competition into the body politic. For example, in Iowa, state law prioritizes competitiveness in redistricting and assigns redistricting to a nonpartisan professional body. |
Four out of Iowa's five congressional districts were potentially competitive in 2002, the first election after redistricting, a far higher degree of competition than existed in other states. This professionalized approach may demonstrate that politics can be largely, if not entirely, removed from the redistricting proc... |
From coast to coast, most politicians are unwilling to contemplate such reform. California State Senate leader Don Perata, D-Oakland, says redistricting reform is unnecessary in California, as bipartisan legislative support exists for the status quo. Given that the status quo guarantees a favorable electoral outcome fo... |
The most viable reform path may be via the initiative process. In recent years, public concern over increasingly uncompetitive elections led Arizonans to approve the creation of an independent redistricting commission. Last week, Schwarzenegger challenged the state legislature to act swiftly on his recommendation or he... |
Historically, redistricting reform has not been a California ballot winner. Most voters are cautious and vote no on such questions. However, Schwarzenegger's demonstrated influence in initiative races may make the difference next time. |
Today, redistricting reform is essential. Over two centuries ago, James Madison warned that no democratic institution should decide the rules of its own membership. It used to be that, in an election, the voters chose the politicians. Now, the politicians choose the voters. There will not be an improvement in political... |
New Zealand Teacher Tries To Ban Gay. |
A primary school teacher from New Zealand has asked his pupil’s not to use the word ‘GAY’ |
Warren Bowers who did his masters degree on homosexuality in education made the statement that from research it appears New Zealand children and teenagers seemed to use "gay" as a negative colloquial, dismissive and disrespectful, or lame term perhaps a lot more than school children in other countries. |
"Quite often teachers just ignore it. Teachers will pull kids up on using sexist language, they’ll pull kids up on using racist language but if kids use that word ‘gay’ quite often, they’ll just let it slide." He said. H wanted to research the subject after an eight-year-old girl in one of his classes, with lesbian par... |
"It does need to be explained that homophobic language is not OK, it’s kind of a last bastion of accepted prejudice." Many teachers were probably unaware of the impact of the word, he said. Although most people used it without intending it to be offensive, "it is offensive and it does hurt people’s feelings" |
It can be very offensive to people, especially the young, saying this is that is gay, meaning they are lame, bad, not working, isn’t very positive, isn’t well lets not put it lightly, is harsh and hateful. |
It is a matter of education, the pupils and the bullies that use the word in that context need to be told that it is hurtful, harmful and homophobic. Kevin Duindam, 17, Monique Hodgkinson, 17, and Helen Ker, 16, are clear indications of the need of such education, because they, as sample school pupils don’t see any... |
Helen said it would be difficult to ban the word without also banning others such as "lame" or "retarded". |
2 responses |
1. i love them large 😉 |
2. well ban me as i love it from behind and underneath !!! |
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Friday, September 16, 2011 |
Creature Feature Friday: Zombies |
I let everyone else go first because my favorite paranormals aren't going anywhere. Today it's my turn and I'm talking about the the undead. No, not the swoon-worthy kind. The risen from the grave, shambling, hungry for your innards, flesh-sloughing kind... |
What are zombies? |
They are the undead! And they are hungry for braaaains! (Okay, you knew all that.) |
How a person becomes a zombie is up for debate. A zombie sinks his teeth into you, and you turn. You get some inexplicably mutated virus, and you die and don't stay dead. You could be raised by a reanimator or a necromancer looking for information or an undead army. Or, if you believe everything you see on television, ... |
What do you love about zombies? |
I'm not sure I can say I love zombies. Intrigued might be a better word. I don't actively seek out undead media, but when it finds me I seem to have trouble turning it away. I suppose it's because zombies are unpredictable. They can be laughable or gruesome or scary. They might even try to find a way to express everyth... |
Yes, they are super-fun in action movies. There's no shame in blowing a zombie to high heaven right? Everybody loves to see the hero take down a zombie hoard with heavy artillery. Admit it. Ving Rhames in Dawn of the Dead. Woody Harrelson in Zombieland. Etcetera, etcetera. You've watched someone blow a hoard of zombies... |
But why are zombies frightening? Is it the threat of rotting grey flesh and a new taste for raw meat? Or is it the existential consequences of becoming undead? One little nip from a hungry straggler and, once the agonizing illness is over and the death tremors have subsided, the victim is entirely stripped of their hum... |
Favorite zombie in fiction: |
R from Warm Bodies by Isaac Marion. Who says zombies can't be gentlemen? |
Favorite zombie in pop culture: |
It's not real a favorite zombie so much as a particular incarnation of zombie. In the TV show The Walking Dead the zombies aren't the slow-moving, mockable things they've been portrayed as for so many years. They are frighteningly twisted mutation of humanity that can do some serious damage. |
If you like zombies, you should read... |
You'll also need this shirt from Shirt Woot. Trust me. It's proof that brains are an acquired taste. |
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