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Comment Re:There must be a very good reason... (Score 5, Informative) 579

Because it is exceedingly expensive to do so.

The issue is that of voltage tolerance. The grid is designed to supply power form central to peripheral. The central voltage is held higher than peripheral, so that the expected voltage drop through supply impedance will result in a voltage at the customer premises which is within tolerance.

If current flow is reversed through the high impedance "last mile", then you can get severe voltage elevation at the point of connection of the generation. This can result in equipment damage (usually the customers) and legal problems for the electricity network operator.

The only way to deal with this problem is to increase the "prospective fault current" of the customer circuit by reducing the system impedance. This isn't something simple like replacing transformers, it is extremely expensive and requires repalcement of cabling with heavier gauge wire, upgrade of safety equipment to withstand the higher fault currents, and may require uprating of transformers and switchgear to handle the magnetic and thermal forces of a fault on the now upgraded circuit.

There are other issues too. Grid transformers are often not designed to operate in reverse power - the tappings are designed for voltage drop in the direction of HV to LV. Under reverse power, there may be insufficient tap range to get satisfactory voltages. Only way around this is to replace the transformer.

Finally, there are second order effects, such as reduced efficiency of transformers when operated in reverse power, due to higher levels of flux leakage from the secondary (primary windings usually go nearest the core, so that stray flux cuts through the secondary and transfers power).

Comment Re:Or, maybe (Score 1) 151

Actually, as cereals/grains make up a large part of the modern diet, the fact that they are poor sources of certain vitamins becomes relevant. For example, breakfast cereal commonly has folic acid added, not because it was lost during process (although some is), but because it is an important public health measure. Same for flour for bread making.

Additionally, some nutrients will be lost from processing - usually cooking, as most breakfast cereals are baked. Many vitamins are heat unstable and are therefore added back by the manufacturers.

Comment Re:Ethanol is a crock nobody wants (Score 4, Informative) 330

Ethanol can be a big problem with certain modern cars.

Toyota and its luxury devision, Lexus, have this problem with models up to 2008. For example, the 2008 Lexus IS (built during calendar year 2007) is not E10 compatible. In areas where E10 fuel was legally mandated, lexus noticed a high rate of warranty replacements of the fuel injection pump and fuel injector failure, as well as fuel leaks from the fuel injection manifold. This was found to be ethanol induced corrosion of the metal alloys used in the injection pump and manifolds. Oxidation and debris from the corrosion would also clog injectors or cause them to leak.

These cars were recalled in the US, but were not recalled outside of the US. Customers with these cars who are now out of warranty are potentially SOL, if they live in an area where E10 is expected to be mandated shortly.

It's not just recent Japanese cars that have problems with E10. Recent european cars also have major problems with E10. Mercedes-Benz vehicles built between 2002 and 2005 are not E10 compatible, as are numerous post 2000 Fiat vehicles, Audi/Volkswagen/Seat/Skoda vehicles with direct injection systems built before 2006, etc. The list of non-compatible cars is very long.

Comment Re:How many people will die because of this? (Score 1) 372

I sense some exaggeration here. In the US CFLs never got that cheap in any size that I've ever seen, even at the mass discount stores. That must have been some massive government subsidy.

Not an exaggeration. Many stores would sell subsidised CFLs for about that price. Same with other energy saving products (I'd seen rolls of thermal insulation material - 10 yards, 6" thick on the shelves at hardware stores for about $2-3 each; but there were big warnings on the shelves which read something similar to the followion - warning! for personal domestic use only. Commercial use of this product is illegal. By purchasing this product, you certify that it will not be resold, used in the course of business or in the construction of a new building)

In fact, the energy suppliers had "energy reduction" targets to meet, and huge fines were levied if they didn't spend $x per year on assisting customers to use less energy. A common way for the energy companies to do this, was to buy massively cheap CFLs from China, claim the cost as a "green expense" and then just mail out unsolicited boxes full of CFLs to every customer. That really did happen, and the bulbs were the lowest possible grade available. The best bit, was that the energy companies could claim the cost of the CFLs as a "green expense", and the government would fund them. Where did the govt get the money from, it came from a surcharge on energy bills. It was even better for the energy company, if they could get a kick-back from the CFL vendor as part of a big order at list-price.

The cost of these "green projects" added to domestic energy bills comes to about $250 per household per year, accounting for about 15% of the total cost.

Comment Re:Cue the Unintended Consequences (Score 1) 372

I've had the same LED light interference problem. At work, at the exit to the car park, they have flashing warning lights. They recently switched from incandescent to LED. Now when you drive past, you lose FM reception when the lights are in the on phase.

Maybe it's a bad batch of lights, but the flashing isn't synchronised between all the bulbs, and you can hear different interference sounds on the radio and work out which bulb they relate to.

I've also had CFLs do the same thing, but those were super cheap junk ones.

That said, incandescents can also produce RF interference that in certain instances can be troublesome. I've certainly seen an incandescent bulb with a failing filament produce enough RF to render an MRI scanner unusable (this is actually a common fault found on MRI scanners with an "excessive image noise" service call). The mechanism is that a tiny develops at a weak point in the filament, but strikes an arc between filament ends. It is the arc (disturbed by vibrations in the filament, convection currents, etc.) that modulates the current in the MHz range.

Comment Re:MRI (Score 5, Interesting) 57

Probably a lot less susceptible.

The main concern with MRI and pacemakers is not so much the magnetic field but the RF field. The magnetic field is not without problems as most pacemakers contain a reed switch which is used to activate "safe mode", where the pacemaker enters a special diagnostic mode. This is largely for historical purposes, as early pacemakers used this for battery level testing. The doctor would hold a magnet to the patient's chest. The pacemaker would enter diagnostic mode and would stimulate the heart to beat a rate dependent on battery voltage. The doc would feel the patient's pulse and could look up the estimated battery level in a table.

Modern pacemakers contain rather more sophisticated NFC capability, so much more useful readouts are available with a proper scan tool (battery voltage, stimulation mode, inputs from various sensors, lead impedances, stimulation voltages and currents, etc.) as well the ability to reconfigure various modes (e.g. vibration response - where the pacemaker increases rate in response to exercise induced vibration), whether the pacemaker can sense other heart parameters (so that different chambers of the heart contract synchronously), etc. In general, however, a magnet will switch the pacemaker into a basic mode of operation. (Defibrillators are different, as basic stimulation can be very dangerous in people with severe heart disease, as it can trigger ventricular fibrillation; therefore magnet mode in implantable defibrillators usually only just tweaks some parameters, rather than anything more dramatic).

The major issue with MRI is the RF field. MRI requires a very powerful RF pulse. A typical MRI power amplifier will take up 6U of rack space, and about 5 gallons per minute of cooling water and need a 3phase 480V power supply, while providing a peak RF power output of 35-70 kW.

A modern pacemaker will typically sense the ECG as well as stimulating. It will include a watchdog timer, and if a beat is not detected before the timer expires, it will trigger a stimulation pulse. One risk with the MRI environment is that the capability of the pacemaker to sense the 1 mV ECG signal may be degraded by the pulsed transmission from the 70 kW RF transmitter 6 inches away.

There are other issues with conventional pacemakers. Being implanted near the shoulder, the pacemaker connects to the heart muscle via leads approx 8-12 inches long. These typically form an arc in shape due to the anatomy. It just so happens that this wire loop forms quite a nice 1/4 wave loop antenna tuned to the scanner's RF frequency; it can absorb the RF energy and channel RF into the tissues around the pacemaker "box" and at the electrode tips. In minor cases, the RF pulses can act as pacemaker pulses on the cardiac muscle. Fine at 1 Hz scan rate. Not so good at 5 Hz scan rate. In extreme cases, the voltage build up across the pacemaker leads can cause RF burns to the cardiac muscle or damage the pacemaker circuitry. (There are MRI compatible pacemakers around which use various tricks - upgrading from normal coax cables to coax with heavy copper screens so rigid that they actually have to be articulated in order to bend + a liberal helping of ferrite beads; or dividing the leads up into 1" segments interconnected by small ferrite transformers)

The nanostim device doesn't have any exposed leads, so it is likely to be much less susceptible to RF problems. Due to size and location, it's also likely that it doesn't feature a conventional magnet mode, relying instead completely on NFC for control and communication. It also has the option of being completely removable. Conventional pacemakers often aren't, as the leads are generally not retrievable from where they screw into the heart muscle. Because it is RF pick-up in the leads that is the No 1 hazard with MRI, simply removing the pacemaker device, but leaving the leads isn't a safe option (it may actually make it worse, as the pacemaker itself often contains clamping and termination circuits to protect itself from EMI, and this serves to absorb some of the RF pick-up from the leads).

So this looks like a very interesting device. However, by the looks of things it can only offer single "lead" functions (i.e. sense the presence or absence of a beat, and stimulate when a timer expires). This type of pacing is "asynchronous" as it is not synchornized with the top of the heart. In normal cardiac operation, the top (atria) of the heart beat first, pumping blood at low pressure to the bottom (ventricles) of the heart, where the pressure is boosted. In asynchronous pacing, cardiac function is reduced as the top and bottom stages of the heart are desynchronised. The preference with conventional pacemakers is synchronised pacing, where an atrial electrode senses the atrial ECG, and when a beat is detected, it triggers a ventricle stimulation after a physiological delay.

Comment Re:Not News: They put it into brake service mode. (Score 4, Informative) 390

Correct. On this type of hybrid vehicle, there is a regenerative braking system.

Under normal driving conditions, while the vehicle is in motion, the motor/generator will be used to retard the vehicle. The brake pedal is connected to a electronic pressure sensor, and also mechanically to a hydraulic master cylinder.

Unlike on conventional vehicles, there is no vacuum powered booster, instead the master cylinder hydraulics are used to operate an electro-hydraulic servo, with electronic override. This way, under emergency braking, you get full hydraulic force applied to the wheel cylinders with minimal pedal effort. The electronic hydraulic control will also apply hydraulic pressure when the vehicle is stationary and the brake pedal depressed, and also periodically applies hydraulic pressure when the vehicle is stopped and the transmission in P (for self-test purposes) and when the vehicle is powered on.

The hydraulic servo mechanism can be disabled in order to permit brake maintenance (this releases hydraulic pressure in the booster and prevents automatic application of pressure to the wheel cylinders), permitting access to maintain the friction surfaces. It appears that this hack, merely consisted of transmitting the CAN bus command to put the hydraulic servo system into maintenance mode.

At low speeds, when the electrical regen isn't operative, this will result in the brake pedal travelling further than expected and loss of power assistance. However, with sufficient pedal pressure, it should be possible to slow the car using unboosted pressure.

Comment Re:How does... (Score 1) 186

There is commercial software available and certified by the government for destruction of sensitive data and "confidential" classified data.

The use of free software is not an approved method of data destruction for bulk personal data in the UK, and its use could technically lead to legal problems. In practice, if it was used correctly, then no one would ever know.

The problem is that the legal onus is on the person in possession of the data to provide documentary proof that the data has been destroyed in an approved manner. If you can't provide proof of the use of an authorized method and validation of success, then you could be prosecuted. For this reason, normal practice is to hire an independent contractor who will provide a certificate stating the method used.

Comment Re: How does... (Score 1) 186

In a previous case where a certifed contractor was hired to destroy the data, but sold theequipment on ebay, the NHS hospital was fined, not the contractor. The reason given by the information commissioner's office, was that the NHS staff should have supervised the contractor and independently verified the destruction.

It was left for the NHS hospital to sue the contractor for breach of contract.

Comment Re:It could work securely (Score 4, Informative) 192

This type of scanning key cutting machine has been around for ages - the storing of the key bitting is new.

In general, this type of machine designed for public use, is only loaded with blanks for "unrestricted" keys.

"Do not duplicate" keys are not protected by just being labelled, they are physically a different shape (often with patented curves and bends), and genuine blanks can only be bought by registered locksmiths who have signed an agreement with the manufacturer not to duplicate keys without proof that the customer is authorised to duplicate that key.

Manufacturers do cut off supply to locksmiths that engage in unauthorized duplication (if they find out). Similarly, the manufacturers will use patent laws to block sale of 3rd party key blanks.

You can still get unauthorized copies made, but it's more difficult. The higher end manufacturers part-key the key blanks to a locksmith's unique code (using difficult to copy modifications - e.g. holes drilled to a specific depth along the length of the key, or curves engraved on the side of the key); a locksmith can only obtain blanks to duplicate keys that he himself sold, making it much easier to trace unauthorized duplication.

Comment Re:Patch cycles (Score 2) 40

The problem with implantable devices is that they are severely power constrained, as typically a battery life of less than 5 years is considered unacceptable, with 10 years wanted for something like a cardiac pacemaker.

This leaves very little power for CPU/communications/encryption functions. Any kind of crypto hardware, or any kind of unnecessary complexity in the firmware (e.g. duplicated bound checking, etc.) is likely to increase energy consumption and shorten battery life.

This is becoming less of a problem with modern silicon which is more power efficient, and the use of NFC and induction coils can support the energy required for communication; so there is less excuse for including some form of well designed security on the device.

I have managed to reboot an implanted nerve stimulator once, by scanning the patient it was implanted in, in a top-end 3 Tesla MRI scanner. Interestingly, everything other than program code, was stored in RAM, rather than flash (including stuff like serial numbers, electronically readable model number!!, as well as treatment parameters). After the device rebooted all these settings were lost. The manufacturer had anticipated this, and the MRI instructions for the device, specifically said that these must be read-out of the device and a hard copy made, with instructions to how reprogram the device if it did reboot.

There are different constrants with non-implanted devices (e.g. laboratory equipment, scanners, servers, etc.) Traditionally, all the specifications for these devices were made at the time when they would be connected a clean, isolated network. As a result, security has been a very, very late arrival to these specifications. TLS support was ratified into the DICOM specification a few years ago (storage and transmission of X-ray/CT/MRI,etc) - but I've never come across a DICOM TLS installation in the field. So little installed software supports it, and the replacement cycle is so long (many hospitals are signing 10 year contracts for a particular version of the software) that it is, at present, completely useless. Even basic level network security is made difficult by certain aspects of the protocol - e.g. DICOM network connections cannot traverse NAT (due to a classic-FTP-like protocol for initiating file transfers, and due to the fact that both client and server nodes must be on pre-configured static IPs) and has enough tricks up its sleeve that it will catch out unwary net admins when they try and configure firewall permissions, or unwary sysadmins who try and set up clustered servers

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