Broadcast Engineer at BellMedia, Computer history buff, compulsive deprecated, disparate hardware hoarder, R/C, robots, arduino, RF, and everything in between.
3362 stories
·
3 followers

Cheap Torque Sensor Goes Back to Basics on Strain Gauges

1 Share

Sooner or later, we’ve all got to deal with torque measurement. Most of us will never need to go beyond the satisfying click of a micrometer-style torque wrench or the grating buzz of a cordless drill-driver as the clutch releases. But at some point you may actually need to measure torque, in which case this guide to torque sensors might be just the thing.

[Taylor Schweizer]’s four-part series on torque is pretty comprehensive. The link above is to the actual build of his DIY torque transducer, but the preceding three installments are well worth the read too. [Taylor] describes himself as an e-waste connoisseur and tantalizes us with the possibility that his build will be with salvaged parts, but in the end a $20 bag of strain gauges and an LM358 were the quickest way to his proof of concept. The strain gauges were super-glued to a socket extension, hot glue was liberally applied for insulation and strain relief, and the whole thing wired up to a Teensy for data capture. A quick script and dump of the data to Excel and you’ve got a way to visualize torque.

An LCD display for real-time measurements is in the works, as are improvements to the instrumentation amp – for which [Taylor] might want to refer to [Bil Herd]’s or [Brandon Dunson]’s recent posts on the subject.

[via r/arduino]


Filed under: tool hacks
Read the whole story
tekvax
7 days ago
reply
Burlington, Ontario
Share this story
Delete

How Lasers Actually Work

1 Share

Lasers are optical amplifiers, optical oscillators, and in a way, the most sophisticated light source ever invented. Not only are lasers extremely useful, but they are also champions of magnitude: While different laser types cover the electromagnetic spectrum from radiation (<10 nm) over the visible spectrum to far infrared light (699 μm), their individual output band can be as narrow as a few µHz. Their high temporal and spatial coherence lets them cover hundreds of meters in a tight beam of lowest divergence as a perfectly sinusoidal, electromagnetic wave. Some lasers reach peak power outputs of several exawatts, while their beams can be focused down to the smallest spot sizes in the hundreds and even tens of nanometers. Laser is the acronym for Light Amplification by Stimulated Emission Of Radiation, which suggests that it makes use of a phenomenon called stimulated emission, but well, how exactly do they do that? It’s time to look the laser in the eye (Disclaimer: don’t!).

The Optical Amplifier

When we talk about the amplification of electrical signals, we are typically not too concerned about whether or not the amplified signal is actually the original signal – just amplified. The minuscule flow of electrons in a bus line may transport a signal, but this signal is not bound to that exact representation. We can send it through a transformer, optocoupler or piezo-transducer and, if we do it right, it just won’t matter. We are really ok if an amplified signal is a good, enlarged copy, as long as the copy retains the subset of properties of the original signal we are interested in.

Light is however indeed bound to its inherent representation as an electromagnetic wave. To understand how light is amplified – or copied – we need to look at the different properties of light both as a wave and as a particle. As a wave, it’s really not much more than synchronized oscillations of electric and magnetic fields propagating through space. To amplify it, we would want to somehow increase the amplitude of this oscillation while leaving its temporal course, such as its phase and frequency, intact. As a particle, however, a photon of a certain wavelength, direction, and polarization – all we can do is add more. So, if take this photon and we add another photon with this very same properties – a copy so to speak – we will see that the amplitude of our electromagnetic wave also doubles. It is amplified.

Since all we can do to amplify light, an optical amplifier must contain some kind of photon xerox — only this one really needs to leave the numbers intact. In lasers, this task of copying photons is done by special atoms (or molecules) inside the optical amplifier. They are called the active laser medium, and in a Helium-Neon laser, for example, it’s the Neon gas. All it needs is a container, an energy source, and some kind of windows for light to enter and exit. This contraption is the key element of every laser, from laser diodes over CO2 laser tubes to fiber lasers.

How To Make A Photon

Most photons we see in everyday life originate from a process called spontaneous emission. Atoms and molecules can be stimulated to transition to higher energy states than their ground state, in which the outer electrons leave their regular orbits and transition into more energetic states. If this state of excitation is long-lived (metastable), they may stay in this state for quite a while, but always keep a certain tendency to translate back to a lower energy state. Sooner or later, they will do so – spontaneously – while emitting a photon of a certain frequency in a random direction and with a random phase. This is called spontaneous emission, and the frequency of the emitted photon depends on the energy differential between the high (E2) and low energy state (E1). Compact fluorescent lamps, as well as incandescent lamps with a halogen filling, make use of this phenomenon.

ucapw_lasers-02

How To Copy A Photon

Now, if a photon of this exact frequency f21, collides with such an excited atom, it can stimulate the atom to transition back to the low energy state right away, before it has time to do so spontaneously. The electromagnetic field of this original photon causes the atom to turn into an electrical dipole and oscillate with the external field. This deep interaction causes the emitted, new photon to take on the same phase and direction as the original one, which makes it practically a copy. Regarding most of the special properties of lasers, such as high monochromaticity, coherence and diffraction limited divergence angle, this quantum mechanical interaction is pretty much the bottom of the barrel.

However, inversely to stimulated emission, incoming photons can also run into atoms of the laser medium that are in the low-energy ground state. These photons will be absorbed, exciting the atom to the corresponding high-energy state. Unless another photon collides with the same atom soon enough to cause a stimulated emission, this atom is likely to spontaneously fall back to its ground state. It will still release a photon, but the photon released in a spontaneous emission can have any direction or phase and won’t align with the absorbed photon’s direction or phase, which results in an attenuation of incoming light.

Population Inversion

With a large number of atoms of the gain medium, the actual amplification process becomes a statistical sum of collisions. If there is a higher concentration of atoms in a low energy state than in the high energy state, we will experience a net loss of photons and thus, an attenuation of light. If the number of excited atoms is larger than the number of low energy atoms, we will experience a net gain. This overbalance of excited atoms is called the population inversion, and it is a basic requirement for optical amplification.

However, with an overbalance of excited atoms, such a two level system becomes highly unstable – it’s practically impossible to maintain. To achieve a population inversion in a stable system, optical amplifiers and lasers make use of more than two excitation levels of the involved atoms. For example, by exciting atoms from the ground state E1 to an excitation state E3, a population inversion between E3 and an intermediate energy state E2 can occur even if more low energy atoms are present in the ground state E1. As long as atoms transition from E2 to E1– for example by a secondary spontaneous emission – at the same rate as atoms are lifted up from E1 to E3, the light amplification process at f32 can happen.

Pump it

To achieve the primary excitation of the laser medium to just the right high energy state, we need a mechanism to lift its atoms up there. This action is called pumping. Different types of lasers use different pumping methods, but besides keeping it going in an efficient and feasible way, it has little effect on the stimulated emission process itself. In some cases, the pumping itself is done by secondary light sources, such as discharge tubes or light emitting diodes. In other cases, the pumping is a well-designed bucket-chain of electrons and atoms or molecules passing on energy from a high voltage source to the atoms of the laser medium.

Energy levels of the Helium-Neon laser by Dr. Bob CC BY-SA 3.0 (edited, image source) Energy levels of the Nd:YAG laser by Sawims (edited, image source) Energy levels of the CO2 laser by Wisem (edited, image source) Energy levels of the ruby laser by Markus Köhler CC BY-SA 2.5 (edited, image source)

The first laser ever built, the ruby laser, uses photons emitted from a Xenon flash tube to excite chromium ions suspended in a synthetic sapphire. Other crystal lasers, such as Nd:YAG lasers, can be pumped by either arc lamps (or flashes), typically Xenon or Krypton, or more efficiently by light emitting diodes. Generally, diode pumped solid state lasers (DPSSL) use photons emitted from semiconductor diode junctions to pump various laser media.

Helium-Neon laser by Tommy Markstein CC BY-SA-3.0 (image source) Nd:YAG laser by Kkmurray CC BY 3.0 (image source) Powerful CO2 laser igniting target (image source) Components of the first ruby laser by Guy Immega CC0 (image source)

CO2 lasers use electron collisions to induce a molecular oscillation in N2 molecules, which then pass on their energy and excite the CO2 laser medium. Helium-Neon lasers utilize electron collision to excite Helium atoms, which then collide with and excite the laser medium Neon. Except for CO2 lasers, which are still commonly used in laser cutters, the intricate pumping mechanisms that involve special gas mixtures and high voltages are more and more replaced by diode-based solid state alternatives.

The Optical Oscillator

While the optical amplifier may already be called a laser in a way, most optical amplifiers will not lase on their own. Any amount of photons that is going to be amplified while passing through the amplifier is bound to leave the amplifier very quickly — with light speed — and gone they are. On their way, they will not necessarily experience enough collisions with the atoms of the laser medium to achieve any reasonable lasing action. To make things worse, the optical amplifier amplifies light in all directions, which makes it a CFL tube at best. There are a few tricks to overcome this: One is, to give the optical amplifier a very, very long and narrow shape so that the only photons passing along this long axis of the amplifier will be amplified. Another way can be to increase the density of the gain medium. And eventually, mirrors can be installed on both ends of the optical amplifier to conveniently increase the effective length of the amplifier.

ucapw_lasers-08

Because high-density gain mediums come with other challenges, such as high breakdown voltages for gaseous mediums, mirrors (and oftentimes long tubes) are the way to go here. Using mirrors, you can also create what is called an optical oscillator. Similar to a mass on a spring, an elastic string, or an LC-oscillator, they oscillate in resonance with a certain frequency. An optical oscillator is even easier to set up, since the main material you need is a chunk of space, with two mirrors on each end to prevent the light from exiting and getting absorbed. In this optical cavity, photons, light or electromagnetic waves (depending on how you look at it) can bounce back and forth between the two mirrors, superimposing to a standing wave.

ucapw_lasers-10

You may have seen this before, it looks like a standing wave on a string. An optical oscillator behaves very similarly: The modes of this optical cavity are solely dependent on the propagation speed of the wave, in this case lightspeed, and the length of the cavity L. The modes — or resonance frequencies — that fit into our cavity depend mostly on the length of the cavity. If we choose the cavity to be long in comparison to the wavelengths we are interested in, in the hundreds of nanometers for visible light, the frequency response of this cavity shows many tightly and evenly spaced modes. If we choose the length of the cavity to be shorter, the spacing fs between the modes increases. This spacing is an important factor for the power output of industrial multimode lasers, which therefore typically have much longer cavities than for instance diode lasers in optical drives that rely on single frequency operation.

ucapw_lasers-11

However, all oscillators are subject to losses, and we need to overcome them to keep any oscillation going. In lasers, this is done by — you may have guessed it — the optical amplifier. The optical amplifier goes right in between the mirrors, and if it’s strong enough to overcome the losses of your system, mostly the small amount of absorption in the mirrors, this system will oscillate.

This oscillation is called lasing, and it is really nothing more than electromagnetic waves bouncing back and forth between the mirrors, experiencing resonance from the cavity and recovering their losses when they pass through the amplifier. To make use of them, usually only one of the mirrors is highly reflective, typically 99.9 % or more. The other mirror, the output coupler, is partly transmissive and allows for a small amount, about 1%, of radiation to exit the cavity. Of course, the amplifier also has to compensate for this amount.

How The Laser Starts Lasing

Once we’ve put everything together, our optical cavity with the output coupler and the optical amplifier, we will want to turn it on. The pump medium will start elevating the laser medium to its high energy level, but there is no light inside the cavity to be amplified yet. Still, even with no incoming radiation, some of the excited atoms in the laser medium will randomly translate to a lower energy state, emitting a photon of just the right wavelength, but with random phase and into a random direction. We need only a few of them with the right phase to be directed along the axis of the optical cavity to get the avalanche going. These initial photons will bounce back and forth between the mirrors of the cavity, getting amplified each time, and the laser starts lasing.

Multimode Lasers

Optical cavities support all modes that fit in between the reflectors, so the exact number of wavelengths of light a laser produces depends mostly on the bandwidth of the optical amplifier. If its bandwidth is narrow, it may cover only a single mode of the optical cavity. If its bandwidth is large, multiple modes of the cavity can be amplified, and because this usually allows for a higher utilization of the pump mechanism, it naturally comes with a higher efficiency. Most industrial high power lasers actually don’t emit only a single frequency, but many. This is possible even though the gain medium operates at a very specific frequency defined by its excitation states, and comes by certain side effects depending on other characteristics of the gain medium. In gas mediums, the collisions of photons with atoms or molecules can shorten the decay time, which — following the statistics of these collisions — shapes the bandwidth of the amplifier to a bell curve. Also, Doppler effects due to the fast movement of gas atoms can further broaden the gain curve. There are many secondary imperfections in the various processes of pumping and stimulated emission that are used productively in multimode lasers.

Pulsed lasers

By pulsing a laser, a larger peak power output can be achieved than what continuous operation would make possible. This can, for example, be done electronically, or through a spark gap circuit, and with shorter pulses, higher peak power output values can be obtained. However, limitations in power output and pulse widths limit the usefulness of this approach.

Multimode lasers offer the possibility of achieving extremely short pulses at a very high momentary power output simply by combining the phase-locked modes of the optical cavity. By combining a series of equally spaced modes in the frequency domain, the interference of the modes causes the output to become a series of pulses in the time domain.

ucapw_lasers-12

The phenomenon of beat, an acoustic interference of sound, where two tones of slightly off frequency create a perceived pulsation of the volume, is very similar. The more modes are superimposed, the shorter and more intense the pulse becomes, and in multimode lasers, they can be as short as a few femtoseconds (10-15 s) while producing several exawatts (1018 W) of peak power.

ucapw_lasers-13

To achieve this, the modes of the optical cavity need to be tight enough spaced to fit as many as possible into the bandwidth of the optical amplifier. Also, the optical amplifier should have a large enough bandwidth to amplify more than a single frequency.

A Primer On Laser Optics

We still left out a few interesting features hidden in the internal optics of lasers, which are mostly the reflectors. First, the reflectors don’t need to be external, they can be evaporation deposited directly onto the polished windows of the optical cavity. Still, to make the output frequency of the laser tunable – which can be easily achieved by slightly changing the length of the cavity – it is practical to adjustably mount at least one of the mirrors externally. If one or both mirrors are mounted externally, some lasers will be equipped with Brewster windows, which is really just a window with its surface cut to a special angle.

ucapw_lasers-14

This angle – the Brewster angle – is an angle where only light of a certain, linear polarization experiences can losslessly pass without reflections while all other polarizations are reflected away from the cavity and filtered from the beam. This minimizes reflections and polarizes the laser beam.

Also, the reflectors must not be plain. In some applications, it is advantageous to use concave or a mix of concave and plain or even convex reflectors. Now the beam exiting the output coupler is not parallel anymore, but can be converted into a parallel beam of any diameter by using simple optics.

I hope you enjoyed this very close look at the inner workings of lasers and optical amplifiers. There’s still a lot of engineering to get from here to just throwing a piece of plywood into a laser cutter, writing data in an optical drive, or exposing a photomask for silicon wafer production. Nevertheless, we have even seen impressive DIY builds of ruby lasers, CO2 lasers, and TEA lasers. DIY or industrial grade, they all share the same core principle, a quantum mechanical avalanche of cloned photons.


Filed under: Engineering, Featured, laser hacks, Original Art , slider
Read the whole story
tekvax
7 days ago
reply
Burlington, Ontario
Share this story
Delete

Gawking Text Files

1 Share

Some tools in a toolbox are versatile. You can use a screwdriver as a pry bar to open a paint can, for example. I’ve even hammered a tack in with a screwdriver handle even though you probably shouldn’t. But a chainsaw isn’t that versatile. It only cuts. But man does it cut!

aukAWK is a chainsaw for processing text files line-by-line (and the GNU version is known as GAWK). That’s a pretty common case. It is even more common if you produce a text file from a spreadsheet or work with other kinds of text files. AWK has some serious limitations, but so do chainsaws. They are still super useful. Although AWK sounds like a penguin-like bird (see right), that’s an auk. Sounds the same, but spelled differently. AWK is actually an acronym of the original author’s names.

If you know C and you grok regular expressions, then you can learn AWK in about 5 minutes. If you only know C, go read up on regular expressions and come back. Five minutes later you will know AWK. If you are running Linux, you probably already have GAWK installed and can run it using the alias awk. If you are running Windows, you might consider installing Cygwin, although there are pure Windows versions available. If you just want to play in a browser, try webawk.

AWK Processing Loop

Every AWK program has an invisible main() built into it. In quasi-C code it looks like this:

int main(int argc, char *argv[]) {
   process(BEGIN);
   for (i=1;i<argc;i++) {
      FILENAME=argv[i];
      for each line in FILENAME {
         process(line);
      }
   }
   process(END);
}

In other words, AWK reads each file on its command line and processes each line it reads from them. A line is a bunch of characters that ends with whatever is in the RS variable (usually a newline; RS=Record Separator). Before it starts and after it is done it does processing for BEGIN and END (not exactly lines as you’ll see in a second).

Line Processing

Big deal, right? The trick is in the line processing. Here’s what AWK does:

  • It puts the whole line in a special variable called $0
  • It splits the line into fields $1, $2, $3, etc.
  • Variable FS sets the regular expression to use for splitting. The default is any whitespace, but you can set it to be commas, commas and spaces, or even blank lines.
  • Variable NF gets the number of fields in the current line.
  • The line number for this file is in FNR and the line number overall is in NR.

Now the AWK script is what handles the processing. Comments start with the # character, so ignore those. They go to the end of the line. Anything in column 1 (except a brace) is a match. Think of it as an implied if statement. If the expression is true, the code associated with it executes. The BEGIN expression is true when the processing hasn’t started yet and END is for the processing after everything else is done. If there is no condition, the code always executes.
Example:

BEGIN { # brace has to be on this line!
   count=0
}
    { 
    count++
    }
END {
    print count “ “ NR
    }

You can put semicolons like you do in C if it makes you feel better. You can use parenthesis too (like print(…)). What does the example mean? Well, at the start set count=0 (variables are made up as you need them and start out empty which means we don’t really need this since an empty variable will be zero if it is used like a number). There are no types. Everything is a string but can be a number when needed.
The brace set in the middle matches every line no matter what. It increases the count by 1. Then at the end, we print the count variable and NR which should match. When you write two strings (or string variables) next to each other in AWK they become one string. So that is really just printing one string made up of count, a space, and NR.

Something Practical

Here’s something more interesting:

BEGIN { # brace has to be on this line!
  count=0
  }
count==10 {
   print “The first word on line 10 is “ $1
}

This prints the first word ($1) of the 10th line of input. If you don’t give any arguments to print, it prints $0, by the way. Overall, this still isn’t too exciting. Maybe it would be more exciting to use $1==”Title:” or something as a condition. But the real power is that you can use regular expressions as a condition. For example:

/[tT]itle:/ {

This line would match any input line that had title: or Title: in it.

/^[ \t]*[tT]itle:/ {

This would match the same but only at the start of a line with 0 or more blanks ahead of it.
You can match fields too:

$2 ~ /[mM]icrosoft/ # match Microsoft
$2 !~ /Linux[0-9]/ # must NOT match Linux0 Linux1 Linux2 etc.

Functions

AWK has functions for regular expressions in the code too such as sub, match, and gsub (see the manual). You can also define your own functions. So:

/dog/ {
   gsub(/dog/,”cat”) # works on $0 by default
   print # print $0 by default
   next
}
{
   print
}

This transforms lines that have dog in them to read cat (including converting dogma to catma). The next keyword makes AWK stop processing the line and go to the next line of the input file. You could make this script shorter by omitting both the first print and the next. Then the last print will do all the printing.

Associative Arrays

The other thing that is super useful about AWK is that it has a little database built into it hiding as an array. These are associative arrays and they are just like C arrays with string indexes. Here’s a script to count the number of times a word appears in a text:

  {
  for (i=1;i<=NF;i++) {
    gsub(/[-,.;:!@#$%^&*()+=]/,"",$i) # get rid of most punctuation
    word[$i]=word[$i]+1
     }
   }

END {
   for (w in word) {
     print w "-" word[w]
    }
}

Don’t forget you can use numbers too so foo[4] is also an array. However, you can also mix and match even though you probably shouldn’t. That is foo[4]=10 and foo[“Hello”]=9 are both legal and now the array has two elements, 4 and “Hello”!

Another note: $i and i are two different things! In the first pass of the above for loop, i is equal to 1 and $i is the content for the first field (because i is 1). You often see $NF used, for example. This is not the number of fields. It is the contents of the last field. NF is the number of fields.
You can run this script with:

awk –f word.awk

Or, if you are on a Unix-like system, you could start the file with “#!/bin/awk –f” instead and make it executable.

Hacker Use

There are lots of other things you can do with AWK. You can read lines from a file, read command line variables, use shell programs to filter input and output, change output formats, and more. Most C functions will work (even printf). You can read the entire manual online and you’ll find examples everywhere.

You might wonder why hardware hackers need AWK. Next time, I’ll show you some practical uses that range from processing logged data, reading Intel hex files, and even compiling languages. Meanwhile, maybe you’d like to use crosswords to learn regular expressions.

Photo credit: [Michael Haferkamp] CC BY-SA 3.0


Filed under: Hackaday Columns, linux hacks, Skills
Read the whole story
tekvax
7 days ago
reply
Burlington, Ontario
Share this story
Delete

World's largest telescope in jeopardy

1 Comment and 5 Shares

606px-Arecibo_Observatory_Aerial_View

Puerto Rico's Arecibo Observatory is the world's largest radio telescope. Arecibo is an icon of science. It's where scientists proved the existence of neutron stars was proven, discovered the first binary pulsar, made pulsar was discovered, the first direct image of an asteroid, made asteroid was achieved, the first discovery was made of extrasolar planets, and of course transmitted the technology used to transmit the Arecibo Message, an attempt to communicate with extraterrestrial intelligence. And right now, the Arecibo Observatory is facing demolition due to budget cuts. it's facing demolition. Nadia Drake attended meetings this month in Puerto Rico to where scientists, staff, students, and the National Science Foundation discussed discuss the telescope's fate and why it needs to how it could be saved. From Natalie's wondrous "No Place Like Home" blog at National Geographic:

Science isn’t the only concern at Arecibo. In fact, the majority of people at the meetings discussed the role the observatory plays in inspiring and training Puerto Rican students, some 20,000 of whom visit the site every year.

Though it’s hard to quantify, the value of inspiration and education is not insignificant, especially considering how underrepresented Hispanic students are in the sciences.

As evidence, several students involved in the Arecibo Observatory Space Academy spoke about how important their time at the observatory was, and how this pre-college program gave them hands-on research experience that continues to affect their lives.

“I can say that AOSA has had a great impact on my life,” said Adriana Lopez, a 14-year-old space academy alum. “Always, in my life, I’ve been fascinated with space, and it has led me to join several camps, but none of them have affected me like AOSA. This academy provided me with skills not even my own academic institution did."

Luisa Zambrano, a graduate student who’s not only using Arecibo data in her dissertation but is involved in running the space academy, said that 100 percent of academy students that have graduated from high school are now in college. Further, she said, among the more than 150 students that have come through the program, “we’ve been able to maintain almost even male:female ratios—which is very unusual for science. Especially among Hispanics.”

That’s not all.

“Over the last five years, we have had 24 Hispanic students or teachers,” said Robert Minchin, Arecibo’s radioastronomy lead and summer internship supervisor. That might not sound like a lot, he said, but it’s more than the typical graduating class at a U.S university.

“It’s not possible to give someone a research experience if you’re not doing research,” Minchin said.

"With Earth’s Largest Telescope Threatened, Its Homeland Rallies"

Read the whole story
tekvax
7 days ago
reply
Burlington, Ontario
Share this story
Delete
1 public comment
kazriko
8 days ago
reply
Crowd Funding? Donations from the international scientific community? It does make me wonder how they spend 12 million a year there. The 8 million from the NSF might be able to be replaced with the 100,000 tourists. That's still a bit prohibitively expensive for a lot of people if you charged $80/person for tickets. You'd probably have far fewer visitors if you did charge that steep of price. Maybe a mix of funding sources?
Colorado Plateau
superiphi
6 days ago
is that all it costs? I mean, start ups that allow you to share cat pictures waste more than than in a year...
kazriko
6 days ago
The article says that their current government funding is $12 million, 8 from NSF and 4 from NASA.

Have your body turned into effluent and just poured down the drain when you die

1 Share

54556160_resomation_shell-1

A funeral home in Ottawa, Canada, is using a new body eco-friendly disposal technique called Alkaline Hydrolysis, which leaves only a coffee-like slurry that can be simply poured down the drain.

Aquagreen Dispositions began operating in a rental unit within the former Rideau Regional Centre in Smiths Falls in May 2015 after receiving a licence from the Ontario government. Hilton's Unforgettable Tails, a parallel business handling the remains of pets, had been using the same process for a couple of years prior to Aquagreen Dispositions, but it took longer to get a licence to handle human remains.

The owner, Dale Hilton, who is from a family of funeral home operators in Smiths Falls, said he watched as the "green wave" swept through the funeral industry, bringing biodegradable caskets and urns.

We've covered the technique before here and here, where John Brownlee pointed out that a straightforward chemical disposal process is, if nothing else, more dignified than the disgusting bilking-of-the-bereaved that oftentimes goes on at funeral parlors.

Nevertheless, "we keep an eye on these things," a local water quality official, Ted Joynt, told CBC News.

Cremations take hours to complete and release carbon dioxide; the alkaline disposal system uses potash, salt and water to "break down a human body in a heated, pressurized vessel" that allows implants and artificial joints to be recovered and reused.

In wide use for animal disposal, similar equipment can be seen at Pri-Bio's Thermal Tissue Digester product page.

Here is a deleted scene from Dune where a body is broken down to water and the remains given to the dead man's killer, who must safeguard it for the tribe. This is probably just like the funerals going on in Ottawa nowadays.

https://www.youtube.com/watch?v=KSoxsH37yxw

Read the whole story
tekvax
7 days ago
reply
Burlington, Ontario
Share this story
Delete

Intel x86s hide another CPU that can take over your machine (you can't audit it)

1 Comment and 2 Shares

PIC12C508-HD

The Intel Management Engine (ME) is a subsystem composed of a special 32-bit ARC microprocessor that's physically located inside the chipset. It is an extra general purpose computer running a firmware blob that is sold as a management system for big enterprise deployments.

When you purchase your system with a mainboard and Intel x86 CPU, you are also buying this hardware add-on: an extra computer that controls the main CPU. This extra computer runs completely out-of-band with the main x86 CPU meaning that it can function totally independently even when your main CPU is in a low power state like S3 (suspend).

On some chipsets, the firmware running on the ME implements a system called Intel's Active Management Technology (AMT). This is entirely transparent to the operating system, which means that this extra computer can do its job regardless of which operating system is installed and running on the main CPU.

The purpose of AMT is to provide a way to manage computers remotely (this is similar to an older system called "Intelligent Platform Management Interface" or IPMI, but more powerful). To achieve this task, the ME is capable of accessing any memory region without the main x86 CPU knowing about the existence of these accesses. It also runs a TCP/IP server on your network interface and packets entering and leaving your machine on certain ports bypass any firewall running on your system.

While AMT can be a great value-add, it has several troubling disadvantages. ME is classified by security researchers as "Ring -3". Rings of security can be defined as layers of security that affect particular parts of a system, with a smaller ring number corresponding to an area closer to the hardware. For example, Ring 3 threats are defined as security threats that manifest in “userspace” mode. Ring 0 threats occur in “kernel” level, Ring -1 threats occur in a “hypervisor” level, one level lower than the kernel, while Ring -2 threats occur in a special CPU mode called “SMM” mode. SMM stands for System-Management-Mode, a special mode that Intel CPUs can be put into that runs a separately defined chunk of code. If attackers can modify the SMM code and trigger the mode, they can get arbitrary execution of code on a CPU.

Although the ME firmware is cryptographically protected with RSA 2048, researchers have been able to exploit weaknesses in the ME firmware and take partial control of the ME on early models. This makes ME a huge security loophole, and it has been called a very powerful rootkit mechanism. Once a system is compromised by a rootkit, attackers can gain administration access and undetectably attack the computer.

(more…)

PIC12C508-HD

(more…)
Read the whole story
tekvax
13 days ago
reply
Burlington, Ontario
Share this story
Delete
1 public comment
zippy72
12 days ago
reply
OK, really good reason never to buy Intel processors right there...
FourSquare, qv
kazriko
12 days ago
Certainly an argument against a single vendor monoculture.
Next Page of Stories