2011年10月31日星期一

Felled coconut tree cuts power in South

A felled coconut tree caused a five-hour power outage in General Santos City and Sarangani province on Sunday, an official of the National Grid Corporation of the Philippines said yesterday.

Milfrance Q. Capulong, NGCP Mindanao regional corporate communications officer, said the power outage started at 3 p.m. with the tripping of the Matanao-GenSan 138-kilovolt line.

“A coconut tree fell in between tower numbers 38-39... Clearing works were completed and power restored at 8:20 p.m.,” she said in a text message.

The affected line is in Barangay San Pedro, Kiblawan town in Davao del Sur. Ms. Capulong did not say why the tree fell on the transmission line.

At the weekend, Davao Light and Power Co. also explained an electrocuted bird broke the line suspension insulator that resulted in an outage in a major section of Davao City’s downtown on Friday.

“Customers connected to its Gaisano substation had experienced an unscheduled power interruption , which occurred between 7:34 a.m. to 9:06 a.m.,” a company statement said, referring to DLPC.

Customers include businesses covering at least one square kilometer at the city’s central business district.

Meanwhile, Cynthia Perez-Alabanza, NGCP spokesperson, explained late last week that the recent “red alerts” in the Mindanao grid were due to a generation deficiency caused by the scheduled maintenance of some power plants, and the unexpected shutdown or reduced capacity of others.

During periods of generation deficiency, NGCP implements Mindanao grid-wide power load curtailment to maintain the power grid’s security and reliability.

“It is NGCP’s obligation under the law and its franchise to ensure that the grid operates at an optimum level with due consideration for safety, security and reliability,” Ms. Alabanza said.

Based on NGCP’s power outlook as of yesterday, the system capacity of the Mindanao grid stood at 1,276 megawatts (MW), with a peak load of 1,067 MW, or a reserve of 209 MW equivalent to roughly 20% of the island’s expected demand during the day.

2011年10月30日星期日

Graphene-based transistors may be on the horizon

Graphene is today's miracle material. It is strong, it is flexible, and it conducts electricity. It possibly also wears its underpants on the outside of its tights and rescues kids from burning buildings.

The conductivity part is perhaps the most exciting. Graphene allows electrons to move ballistically, meaning they don't face any resistance, but require an external voltage in order to move. That's actually a blessing and a curse. Modern electonics relies on materials that can be switched from being good conductors to poor conductors by a control voltage. If graphene naturally conducts and that can't be changed, it might not be all that useful for electronics. A couple of papers in Nature Physics report that all is not lost and, with the right structuring, three layers of graphene allows it to be turned from insulator to conductor via a control voltage.

All of this comes about because graphene is not a metal-like conductor. In metals, there are lots of free electrons floating around occupying a continuum of states. These reach right down into the energy regions where one would expect electrons to stay bound to individual atoms. Graphene, on the other hand, is more like a semiconductor—its conducting electrons fall into a discrete range of states, and the lowest energy of these just happens to coincide with that of the highest energy of a bound electron.

Because these two energy states are just barely touching, there is always the hope that you can manipulate the graphene to shift them apart. This shift would create a bandgap, an energy gap between electrons bound to atoms and those that are free to move around. If you can do that shifting on demand, then you have created a graphene switch and the road is open for graphene based electronics and companies like Samsung  could make their shareholders very happy. But how to do it?

It turns out that, although a single layer of graphene has no bandgap, two layers do. Unfortunately, it can't be switched on and off. Researchers were disappointed that three layers of graphene didn't improve the situation.

The natural stacking of graphene provides a mirror symmetry. When you lay the first layer of hexagons down, the second layer will be offset somewhat from the first layer. The third layer, however, directly overlays the first layer. If you then apply a voltage across the layers, whatever effect the first layer has on the inner layer is exactly countered by the top layer. The result is that, yes you have a bandgap, but you can't control it.

Now, a large number of researchers from six or seven institutions have published two papers demonstrating that, if you change the way the graphene stacks, you obtain a voltage-controlled bandgap. In this work, the third layer of graphene does not overlap the original layer, but is offset even further. This breaks the mirror symmetry so that a voltage applied across the sheets will alter their conductivity.

The two groups of researchers showed this in slightly different ways. One group observed the photoconductivity of their graphene sheets as a function of wavelength and applied voltage. They showed that the oddly stacked three layer graphene sheets would generate a larger current for particular colors. That is, the light was exciting electrons out of bound states and into conducting states, indicating the presence of a bandgap. Furthermore, this color changed depending on the applied voltage, indicating that the bandgap was changing with the voltage.

The second group used a more traditional approach, where they measured the conductivity of the graphene sheets as a function of voltage across the sheet. This involved making graphene transistors and lifting the graphene away from the substrate, so, technically, it was a more challenging experiment. However, it is also an experiment immune from claims that the bandgap dependence comes from interactions between the graphene and its substrate. They also went further and looked at how the current depends on temperature and applied magnetic field.

Between these two papers, a fairly complete understanding of the bandgap behavior in three layer graphene has been obtained, leaving only the challenge of making the stuff. Graphene is fairly easy to make, and making structures out of graphene is also fairly easy. But making graphene layers with specific properties is proving to be quite a challenge, so I suspect that this is where the research must be focused before graphene electronics will leave the lab.

2011年10月27日星期四

‘See the district be more proactive'

Jeff Long thinks Huron Valley gets the short end of the stick in funding. Despite that, Huron Valley has success educating its students.

The White Lake man, one of nine candidates seeking one of two seats on the Huron Valley Schools Board of Education in the Nov. 8 election, said addressing the funding inequity among school districts in Michigan would go a long way in ending Huron Valley's financial struggles.

“We need to try to influence legislators to reform funding for all districts, said Long, 47. “Huron Valley is on the low end statewide. We do perform well. We could perform even better if we had the average funding as far as districts get in funding.”

Seeing the direction the state Legislature is taking toward education prompted Long to seek office. Using money from the school aid fund for community colleges and charter schools, he said, compounds funding issues districts have already faced. “If you can correct the funding inequalities, that's short-term and long-term fixes,” he added.

Building improvements are another way to save money down the road. A member of the middle school committee last winter, he learned more about the efficiencies of various buildings. Making buildings more energy-efficient will drop utility costs and lessen the financial constraints the district is facing.

Many buildings are designed in an inefficient way, he said. Using Lakeland as an example, the new front entrance has a vaulted glass front stretching close to 50 feet high. Country Oaks is another example with large outside glass walls.

“Inherently, glass, while beautiful, is not a good insulator,” said Long. “It transfers heat through it easily.”

Alternative energy sources are another option to consider, whether solar, wind or geothermal. Greywater systems can recycle water and reduce costs from pumping even more fresh water or sending it to a wastewater treatment plant. An added bonus can be “to incorporate those systems into education with advanced technologies,” said Long.

There's a number of state and federal grants available, according to Long, to improve energy efficiency.

“We need to take advantage of them before they disappear,” he said. “It helps long-term. That's more money we can spend on education.”

Such improvements would come at a cost, Long noted, but the up-front costs would be worth it.

“With the increased costs of utilities, I'd like to see the district be more proactive. There's no question there's an expense involved,” he said. “It's a long-term, open-ended investment. Most all building improvement is done through bonds and millages. Citizens have been very accommodating in this district when they see the spending is responsible.

“The district does not have the money in its general fund. It we can show the benefits to the public ... I think they may be welcome to it.”

Long, who was endorsed by the Huron Valley Education Association, the district's teachers union, said he pursued that endorsement because he is member of the local electrical union, and he opposes privatization. In the long run, he said, privatization does not save money, and many of the current district employees live in the community.

“Any time a company takes a dollar of profit, that's a dollar not being spent in education,” said Long.

Long said he doesn't think the community is divided. While there's a vocal number of parents expressing their concern, he said he doesn't see it. There is, however, always a rivalry between the Milford-Lakeland set. “I think that's a good rivalry,” he said. “It's good for our district.”

2011年10月26日星期三

Spray Foam Manufacturer Oversees Home Weatherization

Home Weatherization is a household name in the insulation business these days. People have never cared more for the environment as they do today. Energy efficiency is at the top of political debate lists. Government rewards programs, in turn, are handing out rebates right and left for homeowners that perform energy improvements.

Fomo Products, Inc. took advantage of the market opportunity and was at the front line to oversee a home weatherization using their product. “We want to be sure that our product is applied correctly and properly serves its purpose as a quality insulator,” said Tim Shoemaker.

Shoemaker is a Technical Support Field Manager for Fomo Products, Inc., as well as a BPI Certified Building Analyst. Basically, he is a hands-on guy. Shoemaker travels around the world, supporting Fomo Products within the distribution network and participating in particular jobs to oversee the process and assure proper usage of Fomo products.

This particular job was on a 1,475 sq. ft. colonial home in Cuyahoga Falls, Ohio. The house, built in 1912, had an existing insulation system consisting of corrugated cardboard and fiberglass batt insulation in the attic. “It was just a big, leaky, box,” said Shoemaker.

First, Shoemaker and other BPI Certified Building Analysts conducted a blower test, revealing an hourly air exchange of 13.7 ACH50. A smoke pencil and infrared camera were used to locate specific points of air infiltration. Shoemaker cited rim joists as a major “bottom-up” point of entry into the house.

Next, Fomo Products’ Handi-Foam® Spray Foam was applied to the attic floor, in the rim joists and under the bay window to stop air infiltration. R-42 loose cellulose was also added over the top of the spray foam in the attic.

The end result? A 22 percent reduction in hourly air exchanges, leaving the home with a rate of 10.6 ACH50.

Shoemaker said that home weatherization is an important part of the Fomo Products, Inc. industry focus. “Once you have control of the building envelope, every other aspect of insulation will fall into place with more ease,” he said.

2011年10月25日星期二

Digital isolation rivals optocouplers in terms of power, size and performance

For years, designers of industrial, medical and other isolated systems had limited options when implementing safety isolation: the only reasonable choice was the optocoupler. Today, digital isolators offer advantages in performance, size, cost, power efficiency and integration.

Understanding the nature and interdependence of the three key elements of a digital isolator is important in choosing the right digital isolator. These elements are: the insulation material: the structure: and the data transfer method.

Designers incorporate isolation either because of safety regulations or to reduce noise from such features as ground loops. Galvanic isolation ensures data transfer without an electrical connection or leakage path that might create a safety hazard. Yet isolation imposes a number of constraints, such as delays, power consumption, cost and size. A digital isolator's goal is, therefore, to meet safety requirements while minimising incurred penalties.

Optocouplers, a traditional isolation approach, incur the greatest number of penalties, consuming high levels of power and limiting data rates to less than 1Mbit/s. While more power efficient and higher speed optocouplers are available, these impose a higher cost penalty.

Digital isolators were introduced more than a decade ago to reduce penalties associated with optocouplers. These use cmos based circuitry and offer significant cost and power savings, while improving data rates significantly. They are defined by the elements noted above: insulating material determines inherent isolation capability and is selected to ensure compliance to safety standards; structure and data transfer method are chosen to overcome the cited penalties. All three elements must work together to balance design targets, but the one target that cannot be compromised and 'balanced' is the ability to meet safety regulations.

Digital isolators use foundry cmos processes and are limited to materials commonly used in foundries. Non standard materials complicate production, resulting in poor manufacturability and higher costs. Common insulating materials include polymers such as polyimide (PI), which can be spun on as a thin film, and silicon dioxide (SiO2). Both have well known insulating properties and have been used in standard semiconductor processing for years. Polymers have been the basis for many optocouplers, giving them an established history as a high voltage insulator.

Safety standards typically specify a one minute voltage withstand rating (typically 2.5kV rms to 5kV rms) and working voltage (typically 125V rms to 400V rms). Some standards also specify shorter duration, higher voltage (for example, 10kV peak for 50µs) as part of certification for reinforced insulation. Polymer/polyimide-based isolators yield the best isolation properties.

Polyimide based digital isolators are similar to optocouplers and exceed lifetime at typical working voltages. SiO2 based isolators, however, provide weaker protection against surges, preventing their use in medical and other applications.

The inherent stress of each film is also different. Polyimide has lower stress than SiO2 and can be increased in thickness as needed. The thickness of SiO2 and, therefore its isolation capability, is limited; stress beyond 15 µm may result in cracked wafers during processing or delamination over the life of the isolator. Polyimide based digital isolators, however, use isolation layers as thick as 26µm

2011年10月24日星期一

Laser Makes Memory Mechanical

Engineers at Yale University say they’ve invented a new type of mechanical memory device that is read from and written to by light. According to its creators, this development could lead to better sensors and new techniques in optical telecommunications.

The device is essentially a tiny piece of silicon that can be bent up or down by the light propagating inside a photonic circuit. Once the light is switched off, the piece remains in one of those states, representing the 1s and 0s of digital coding. The engineers from Yale who developed the device, which is called a "nanomechanical resonator," described it yesterday in the journal Nature Nanotechnology.

"We really can achieve control of the nanodevice at very high amplitude and repeatability," says Hong X. Tang, an associate professor of electrical engineering, who led the work.

To make the resonator, Tang and his colleagues started with a commercially available silicon-on-insulator wafer and created an oval-shaped waveguide on the wafer to act as an optical cavity. They etched away a bit of the wafer below the waveguide to create a strip of silicon 10 micrometers by 500 nanometers by 110 nm, so they ended up with a membrane of material across part of the waveguide, attached at both ends but free to fluctuate up and down in the middle. Because of stress put on the wafer during the initial process of attaching the silicon to the insulator, this strip naturally buckled a bit. So with no force applied, it would be stable when bent either upward or downward.

When the researchers fired laser light into the optical cavity at a frequency that was slightly higher than the resonant frequency of the cavity, the resonator started oscillating, bending up and down in rapid succession. "If you put extra energy into the cavity, the mechanical resonator will gain energy from the laser field," Tang explains. When the laser was turned off, the oscillation stopped, leaving the resonator in either the up or the down state—a 1 or a 0.

But to make the device effective as memory, the group wanted to be able to control whether the strip came to rest bent up or down, so they turned to laser cooling, the same technique used to slow atoms to a near motionless state. Injecting laser light with a lower frequency than the device’s resonant frequency damped the oscillations. Selecting one damping frequency made it more likely that the strip would settle into the buckle-up state; a different damping frequency made it probable it would stop at buckle-down.

"The two states [up and down] are separated by a huge energy barrier," Tang says. That means with the laser turned off, they stay put, making the memory nonvolatile. The device is also much less sensitive to stray radiation and heat effects that can sometimes switch a bit in electrical or magnetic memory, he says.

To read the memory, the researchers simply use a laser with an energy too low to flip the bits. The position of the resonator changes the refractive index of the optical cavity, so it’s easy to know whether it’s up or down by how the laser light bends.

The optical technique "may enable ultrahigh-speed manipulation" of a mechanical bit, says Pritiraj Mohanty, professor of physics at Boston University, who was not involved in the research.

It takes a relatively large amount of energy—a microjoule—to switch a bit, so Tang says the device as it stands is impractical for large-scale storage. But he says it could be useful for something like an optical router, which doesn’t have to switch too often. It might also be valuable in control circuitry; for example, it could provide timing on a computer chip. And it could make sensors for acceleration or trace gases more sensitive. In fact, the research was funded under a Defense Advanced Research Projects Agency grant for using optical control to improve sensors.

2011年10月23日星期日

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2011年10月20日星期四

Improved oxygen sensor from Broadley-James

The OxyProbe II dissolved oxygen sensor from Broadley-James has a new improved membrane design modelled on the 25 mm membrane cartridge. Suitable for biotechnology applications, it has an expandable inner silicone bladder that holds the electrolyte within a 316L stainless steel cage. During SIP processes or autoclaving the electrolyte turns to steam but does not distend the measurement membrane because the internal bladder expands first. This takes pressure off the sensitive measurement area and keeps the risk of damage to a minimum.

It comes with either a waterproof VarioPin connector or a D9 connector. The standard D9 connector has hermetically sealed gold plated contacts in a glass insulator, giving excellent signal isolation and transmission. The T-pull connector version allows easy removal from a fermenter and reduces strain on the cable.

The sensor can be autoclaved and steam sterilised and features accurate measurement and fast response. It is long lasting and easy to maintain, with FDA approved materials of construction and a hygienically polished N5 surface finish . The wetted O-rings comply with FDA and USP Class VI standards.

The membrane body and inner body can be changed quickly, saving time on maintenance. Because of the modular design, different sensors have the same spare parts so that inventory can be kept to a minimum. Existing 12 mm OxyProbe sensors can be updated to the OxyProbe II design during the rebuilding process.

2011年10月19日星期三

How Can I Avoid Static Electricity Shocks in Cold, Dry Weather?

Without going too deeply into an electrostatics lesson, it's important to know what causes those static shocks so you can start avoiding them. Static electricity "refers to the build-up of electric charge on the surface of objects"—essentially, when electrons move from one surface to another through contact. If the surfaces are both insulators, they'll build up an electrical charge. One object will have a positive charge (because it lost electrons) and one will have a negative charge (because it gained electrons). If one of the charged objects then touches a conductor, like a piece of metal, the charge will neutralize itself, causing a static shock.

What does this mean for you? Well, you have a lot of insulators in your home, like the rubber soles of your shoes and that wool carpet in the living room. When you walk on that wool carpet, your body then builds up a charge it can't get rid of through the insulating soles of your shoes. Then, when you touch that metal doorknob... you know what happens. Dry air is also an insulator, so static electricity is even more common during the dry winter months.

One of the easiest ways to avoid static shock is to pay attention to what you're wearing and what kind of fabrics make up the furniture in your house. For example, Electrostatics.net notes that rubber-soled shoes are great insulators, and will build up a lot of static in your body when combined with a wool or nylon carpet. Instead, try walking around in leather soled shoes, or cotton socks instead of wool socks. Leather soled shoes are also great for grocery shopping, since shopping carts can often cause lots of static electricity.

Similarly, wool sweaters are common offenders, especially in the dry winter (when you usually wear them). If you sit in a chair made out of the right fabric, you'll build up quite a bit of static. Again, cotton is going to be much more friendly, so try wearing cotton clothes when you want to avoid nasty shocks. Certain furniture covers or antistatic sprays can help alleviate this problem, too.

You may have also noticed that often, when you get out of your car, you get a shock when you touch the door. You might have even heard that touching the door frame as you get out of the car can help, and that's true. Make sure you start holding the metal frame before you get out of the car, and you keep touching it until you're out of the seat completely. If you forget to do this, you can also touch the car door with your keys. Since the electricity will discharge through them, you won't feel a shock.

2011年10月18日星期二

Candlelight tour brings past residents to life

The men and women of the township’s past came back to life on two crisp fall nights on Oct. 22 and 23, sharing their tales with visitors as part of the East Brunswick Museum’s annual candlelight tour of the historic Chestnut Hill cemetery.

Several re-enactors, as well as Ken “the singing psychic,” helped to bring the historic residents back to life on a tour that Mark Nonestied, a past president of the East Brunswick Museum who organizes the event, said provides a unique and fun way to teach people about local history.

To uncover the stories behind the names on the cemetery’s tombstones, Nonesteid mines troves of different information, including census records, newspaper archives and other documents to help craft a script about their life and times, a process that takes months. Re-enactors then take the script and dressed in the clothes from the era, present these people to tour-goers, each with their own personality and way of interpreting the person they are playing

“It’s fun,” Nonesteid said. “I think people really enjoy it.”

The portrayals change each year and have included some of the more famous people laid to rest in the cemetery that houses graves dating back to the 1830s — including the 19th-century landscape artist James Crawford Thom and children’s book writer Henrietta Christian Wright — and everyday people as well.

“It’s just a story of the common person from the time period, and that’s a story that’s worth telling,” Nonesteid said.

With 2011 marking the 150th anniversary of the Civil War, this year’s tour worked to tell the stories of historic residents like Catherine Appleby, who lived through or was affected by the War Between the States.

Martha Austin Appleby, born in 1849, was married to Civil War veteran William Appleby, a member of the 28th Regiment of New Jersey Volunteers. William was injured in battle and discharged during the war, reenlisting later in the Navy and serving aboard the USS Nantucket.

Appleby, portrayed by East Brunswick Museum President Kathie Waite, showed 21st-century visitors a letter her husband received from a fellow soldier after the war that stated, “Well Appleby, we did not think then that we were making so much history. The Volunteers took it all as a matter of course.”

The Rev. John D. Killian, a Pennsylvania native who moved to East Brunswick to become the pastor of the Old Bridge Baptist Church, explained his church’s battle over the use of music in the liturgy and the repositioning of the church to face Kossman Street to minimize the appearance of a pigpen outside the church.

“You can’t make up this stuff,” Killian, played by Joe Ungrady of Old Bridge, joked.

But not all actors on tour were from the past. Ken “The Broadway Medium” Roginski, channeled the spirit of Frank Treat and told his tale through Broadway show tunes. Treat’s family owned a hotel on corner Kossman Street and the Old Bridge Turnpike in the early 1900s and served as an important destination, as Old Bridge Turnpike was the major highway to New Brunswick at the time.

“It served the best beer in town,” Roginiski, a Freehold resident, sang. “Friends would often stay here, kids would also play here, I wish that we all were still around.”

Later, Treat worked for the Brookfield Glass Insulator in Sayreville, creating glass insulators for telephone poles and served an important role as the gas lamp lighter for the East Brunswick Historic Village.

“So you know, I lived in the village below,” Roginski sang to the melody of George Gershwin’s “Summertime.” “And we had gas lights on the street that provided the glow. My responsibility was to light the lamps each evening. I was the old lamp lighter of long, long ago.”

Roginski, a historic preservationist who has appeared on TLC’s show “Dead Tenants,” said he has been doing the tour for many years and enjoys the reaction he gets from people during his presentation.

He said that the tour is a great way to teach people about history at a venue, the cemetery, that is perfect for the season and he finds fascinating.

2011年10月17日星期一

Research aims to replace silicon with graphene

A team of researchers from the University of Manchester demonstrate how graphene could be encapsulated, sandwiching two sheets of graphene with another two-dimensional material, boron nitride. The four-layered structure aims to replace the silicon chip in computers.

Because there are two layers of graphene completely surrounded by the boron nitride, this has allowed the researchers for the first time to observe how graphene behaves when unaffected by the environment. Leonid Ponomarenko, the leading author on the paper, said, "Creating the multi-layer structure has allowed us to isolate graphene from negative influence of the environment and control graphene's electronic properties in a way it was impossible before."

"So far people have never seen graphene as an insulator unless it has been purposefully damaged, but here high-quality graphene becomes an insulator for the first time." The two layers of boron nitrate are used not only to separate two graphene layers but also to see how graphene reacts when it is completely encapsulated by another material.

"Leaving the new physics we report aside, technologically important is our demonstration that graphene encapsulated within boron nitride offers the best and most advanced platform for future graphene electronics. It solves several nasty issues about graphene's stability and quality that were hanging for long time as dark clouds over the future road for graphene electronics. "We did this on a small scale but the experience shows that everything with graphene can be scaled up." "It could be only a matter of several months before we have encapsulated graphene transistors with characteristics better than previously demonstrated."

2011年10月16日星期日

3M, IBM team to develop 3D IC adhesive

IBM Corp. and 3M Corp. partner to develop the first adhesives to pack semiconductors into densely stacked silicon "towers". The key remaining obstacle to 3D ICs, according to IBM, is an under fill material that can do double duty as an electrical insulator and a thermal conductor. IBM aims to use the material in conjunction with microfluidic channels containing refrigerants on 3D structures.

IBM + 3M = 3D ICs is actually a catchy formula. "Somewhere in the middle of those initials, 3M has the technology platforms to make 3D work," said Bernard Meyerson, VP of research at IBM.

"3M has the skills to meet the really disparate requirements for a 3D IC adhesive," said Meyerson. "You want infinite thermal conductivity in the adhesive, but you also want the electrical conductivity to be zero."

The worst constraint, according to Meyerson, is that the coefficient of thermal expansion for the adhesive must match that of the metal used for the interconnect; otherwise, the adhesive will break the metallisation when it heats up.

"Thermal conductivity, electrical conductivity and thermal expansion are all related, not to mention brittleness. It's what we call an over constrained system."

Ming Cheng, technical director of 3M's electronics markets materials division, said 3M "is essentially a materials company with the capability to tune the properties of adhesives and polymers to meet even these conflicting specifications. Our adhesive will be a combination of different types of polymers, oligomers and monomers, along with the necessary feelers and adhesion promoters that meet IBM's specifications."

According to 3M, it has not yet been decided whether the jointly developed 3D IC adhesive will be sold to other chip makers. But in the past IBM has made a practice of licensing its key patents even to competitors.

3M also has experience with the fluids that are used today to cool hot spots in rack-mounted computers, and those fluids could soon flow through microfluidic channels cut into 3D ICs. "Even if you have the perfect adhesive, it may be necessary to remove heat from the internal layers of a tall stack," said Meyerson. "A micro channel-cooled radiator halfway through the stack could take out a bunch of heat from the middle of a silicon brick."

Cheng added, "Our Fluorinert electronic liquids are currently used to help cool equipment in data centres—mostly servers and hard drives—but with IBM we will also be exploring the liquids' use to help cool 3D ICs."

Beyond perfecting the processing technologies to interconnect stacked dice and keep them cool, designers must consider the tide of data that will be streaming out of 3D ICs, according to IBM. Photonics will become an integral part of 3D ICs to handle the voluminous I/O.

"Electronic data transmission today can consume up to 50 per cent of a chip's power. Photonics is vastly more efficient in watts per bit and, for that reason, will be essential for 3D ICs," said Meyerson. "We'll need lasers, modulators and detectors right in the 3D IC stack."

The work with IBM was announced just recently, but 3M has been working on 3D solutions for some time. Earlier this year, in fact, 3M announced a technology for handling wafers destined for 3D stacks. The company's wafer-supporting-system (WSS) simplifies the handling of wafers that have been thinned for stacking.

WSS "first bonds the thin wafer to glass with a temporary adhesive so that the glass can support the wafer during bonding," said Cheng. "After the two wafers are stacked, debonding allows the glass [carrier] to be removed."

By 2013, 3M and IBM promise an end-to-end process ready for widespread high-volume commercialisation of heterogeneous stacks of processor, memory, mixed-signal, networking and I/O chips formed into silicon skyscrapers as high as 100 chips per stack.

2011年10月13日星期四

Caring for your engine’s alternator

We barely give a thought to the spark plug. All it does is supply a gap over which a spark jumps. But when you consider its working environment, the plug certainly deserves respect. The nose of the insulator surrounding the central electrode must operate between 350 and 700 degrees C. Too low a temperature will result in carbon build-up and, as carbon is a good conductor, it is not wanted there.

Conversely, if the temperature is too high, pre-ignition is likely. We can get an idea how a plug is running by examining it immediately after a full power run. If the insulator nose is clean and white, it is running too hot and, if black, too cool. The ideal colour is light brown. Use only the plugs recommended for your vehicle.

Charging systems have changed. At one time we had a magneto and dynamo. But, as electrical demands grew, the system was inadequate. The battery handles starting, lights, signals and ignition, and eventually it all became too much for the battery/dynamo setup and alternators appeared.

Unlike the dynamo, even at idle the alternator is charging the battery which is certainly a boon when stuck in traffic for any length of time. The electronic regulator plays a part too because it controls output better than the dynamo and allows the use of maintenance-free batteries. The alternator is not as heavy as a dynamo, has a longer service life and requires less maintenance.

Alternators require an occasional check for dirt on the slip rings and brush wear. When a fault appears, examine cables for splits and breakage and all connections. Check drive belt for signs of slippage. Check the charge warning lamp; if this blows the alternator may not start charging. With battery on charge, look for excessively gassing cells or terminal corrosion.

For basic testing you will need a moving-coil voltmeter. Add a hydrometer, plus a high and low-range ohmmeter and a DC moving-coil ammeter .

Beware; a thermostatically controlled fan can start spinning even though the ignition is off. Before connecting/disconnecting main alternator leads disconnect the battery earth cable - and remember to switch the ignition off before connecting/disconnecting any vehicle cable.

Connect a 0-20V voltmeter across the battery terminals then switch on all loads except the windscreen wipers because wipers may scratch a dry screen. Run the engine at 3000rpm for three minutes. Provided the battery is OK, it should show 13.5V after a minute or two. If it doesn’t, suspect the alternator.

Rotor slip ring brushes can stick in their holders, so clean them and ensure free movement. Minimum brush length varies from system to system, so check the handbook. Corroded or loose battery connections or a poor earth can cause diode failure, as can even momentary connection of the battery the wrong way round. Note that disconnecting the alternator or battery while the engine is running will also cause failure.

The parts which may fail in an alternator are the power and field diode pack, rotor and stator windings, brushes and bearings. When an alternator is more than a few years old, I believe, rather than messing around with individual parts, it is better and to get a reconditioned unit with a guarantee.

2011年10月12日星期三

Graphene's Big Mac creates next generation of chips

The world's thinnest, strongest and most conductive material, discovered in 2004 at the University of Manchester by Professor Andre Geim and Professor Kostya Novoselov, has the potential to revolutionize material science.

Demonstrating the remarkable properties of graphene won the two scientists the Nobel Prize for Physics last year and Chancellor of the Exchequer George Osborne has just announced plans for a £50m graphene research hub to be set up.

Now, writing in the journal Nature Physics, the University of Manchester team have for the first time demonstrated how graphene inside electronic circuits will probably look like in the future.

By sandwiching two sheets of graphene with another two-dimensional material, boron nitride, the team created the graphene 'Big Mac' - a four-layered structure which could be the key to replacing the silicon chip in computers.

Because there are two layers of graphene completed surrounded by the boron nitride, this has allowed the researchers for the first time to observe how graphene behaves when unaffected by the environment.

Dr Leonid Ponomarenko, the leading author on the paper, said: "Creating the multilayer structure has allowed us to isolate graphene from negative influence of the environment and control graphene's electronic properties in a way it was impossible before.

"So far people have never seen graphene as an insulator unless it has been purposefully damaged, but here high-quality graphene becomes an insulator for the first time."

The two layers of boron nitrate are used not only to separate two graphene layers but also to see how graphene reacts when it is completely encapsulated by another material.

Professor Geim said: "We are constantly looking at new ways of demonstrating and improving the remarkable properties of graphene."

"Leaving the new physics we report aside, technologically important is our demonstration that graphene encapsulated within boron nitride offers the best and most advanced platform for future graphene electronics. It solves several nasty issues about graphene's stability and quality that were hanging for long time as dark clouds over the future road for graphene electronics.

"We did this on a small scale but the experience shows that everything with graphene can be scaled up."

"It could be only a matter of several months before we have encapsulated graphene transistors with characteristics better than previously demonstrated."~

Graphene is a novel two-dimensional material which can be seen as a monolayer of carbon atoms arranged in a hexagonal lattice.

Its remarkable properties could lead to bendy, touch screen phones and computers, lighter aircraft, wallpaper-thin HD TV sets and superfast internet connections, to name but a few.

2011年10月11日星期二

EP Student Tests Cool Idea

An Eden Prairie middle school student had a cool idea. She wanted to know if bubbles could keep your bath water warm. So, she tested it. It became her science fair project and it took her to the national stage. She was one of 30 finalists in a huge national science competition!

Her name is Carolyn Jons. She's a student at Central Middle School. She came up with a way to test bubbles floating in a bathtub or whirlpool to see if they have the ability to keep that water warm. She looked at different size bubbles and developed an experiment to test which size acted as a better insulator.    

Jons showed off her project at the Twin Cities Regional Science Fair where she won honors with her science project and research paper at the University of Minnesota in February. The following month, she won additional awards at the Minnesota Academy of Science Minnesota State Science and Engineering Fair in Bloomington.

6,000 middle school students were nominated from regional and state science fairs across the nation to compete nationally. From there, 300 students were selected as Semi-finalists. 30 were chosen as finalists. Jons made it the entire way.

The national competition was in Washington D.C. from September 30 - October 4, 2011.

First place was worth $25,000 and went to a student in California. Second place was worth $10,000 and went to a student in Pennsylvania. And third place, worth $5,000, went to a student in Texas.

Although Jons didn't place at the national level, she did confirm that bubbles do in fact prevent heat loss. She did not find a significant difference in the insulating ability of small versus large bubbles.

Jons hopes to one day enter the field of Neurology. She says she's drawn to neurology because of the many fascinating medical conditions neurologists treat.

2011年10月10日星期一

Electron superhighways could hold key to quantum computing

A group of researchers has claimed the world is another step closer to building a working quantum computer.

They reckon they might have cracked one of the main components of a working quantum processor, a tiny device which functions as a ‘superhighway’ for electrons.

The team at Rice University developed a quantum spin Hall topological insulator that will be able to control and create qubits as part of a quantum processor, and store them as data.

One of the problems that all scientists are trying to overcome in creating qubits is making certain that that the information isn’t lost due to quantum fluctuations, known as fault tolerance.

Although it would only take a quantum processor with 30 qubits to perform around the same amount of calculations as a 1 billion transistor microchip, this is something that scientists have found difficult.

Using topological insulators as the basis of a quantum circuit is expected to help increase fault tolerance - due to each qubit being made from a pair of quantum particles that have a shared identity.

Topological insulators can block electrons from flowing through them, though they can flow around the narrow outer edges.  When attached to a superconductor, this can produce stable pairs of quantum particles called Majorana fermions where the two materials meet, meaning there is the potential to generate qubits.

The problem is that these Majorana fermion stable particles have yet to be observed by physicists, so quantum computers are not exactly within reach just yet.

But the team say that they are “well positioned” for more tests, and hope to find out whether the discovery of Majorana fermions will produce stable qubits.

2011年10月9日星期日

Graphene's 'Big Mac' creates next generation of chips

The world's thinnest, strongest and most conductive material, discovered in 2004 at the University of Manchester by Professor Andre Geim and Professor Kostya Novoselov, has the potential to revolutionize material science.

Demonstrating the remarkable properties of graphene won the two scientists the Nobel Prize for Physics last year and Chancellor of the Exchequer George Osborne has just announced plans for a £50m graphene research hub to be set up.

Now, writing in the journal Nature Physics, the University of Manchester team have for the first time demonstrated how graphene inside electronic circuits will probably look like in the future.

By sandwiching two sheets of graphene with another two-dimensional material, boron nitrate, the team created the graphene 'Big Mac' – a four-layered structure which could be the key to replacing the silicon chip in computers.

Because there are two layers of graphene completed surrounded by the boron nitrate, this has allowed the researchers for the first time to observe how graphene behaves when unaffected by the environment.

Dr Leonid Ponomarenko, the leading author on the paper, said: "Creating the multilayer structure has allowed us to isolate graphene from negative influence of the environment and control graphene's electronic properties in a way it was impossible before.

"So far people have never seen graphene as an insulator unless it has been purposefully damaged, but here high-quality graphene becomes an insulator for the first time."

The two layers of boron nitrate are used not only to separate two graphene layers but also to see how graphene reacts when it is completely encapsulated by another material.

Professor Geim said: "We are constantly looking at new ways of demonstrating and improving the remarkable properties of graphene."

"Leaving the new physics we report aside, technologically important is our demonstration that graphene encapsulated within boron nitride offers the best and most advanced platform for future graphene electronics. It solves several nasty issues about graphene's stability and quality that were hanging for long time as dark clouds over the future road for graphene electronics.

We did this on a small scale but the experience shows that everything with graphene can be scaled up."

"It could be only a matter of several months before we have encapsulated graphene transistors with characteristics better than previously demonstrated."

Graphene is a novel two-dimensional material which can be seen as a monolayer of carbon atoms arranged in a hexagonal lattice.

Its remarkable properties could lead to bendy, touch screen phones and computers, lighter aircraft, wallpaper-thin HD TV sets and superfast internet connections, to name but a few.

The £50m Graphene Global Research and Technology Hub will be set up by the Government to commercialise graphene. Institutions will be able to bid for the money via the Engineering and Physical Sciences Research Council (EPSRC) – who funded work leading to the award of the Nobel prize long before the applications were realised.

2011年10月8日星期六

India has strong technical engineering potential: ABB Group

In developed world, there is a lot of turmoil and uncertainty right now. The euro crisis or the debt crisis in Greek and Europe is causing tremendous uncertainty in the marketplace. The debt issue in the United States is also casting some uncertainty in the marketplace as well in the sense of how the US will get its debt under control.

So, it’s a very uncertain environment. I’m optimistic that the governments will find a politically right way to do things and many economies will move forward. I am very optimistic on India and China. They continue to grow anywhere between 7% and 10%. A lot of our growth will come from the emerging markets in the next three to four years.

We took about USD 3 billion of cost out of this business between 2008 and 2010. We increased our R&D spend by 10-15% year over those years. We also increased our sales spend.

So, it was a conscious decision taken by ABB's management to truly invest in the future. I don't know if all companies have done that way. For example, our R&D to sales ratio or revenue ratio in 2011 will be 4%, up from 3% in 2008. So, we have enjoyed good growth in that side of the marketplace and it has allowed us to invest more than some of our competitors that were more entrenched in the developed world.

There are two parts of it; one is infrastructure build out like the creating power here. We were appointed a job in North-East Agra that we will bring power from different parts of India, hydropower about 2000 kilometers down to the metropolitan areas where it’s needed.

These are huge projects transferring almost 8 Giga watts of energy that will be like 8 nuclear power plants. Those kinds of infrastructure projects are very big. We had a very strong automation business. So, whether it is novelty products or intelligent products like deriver and motors attached to those drives, productivity that really helps to drive industry overall ABB, has a good firm position here.

There is a regulatory concern when you do large infrastructure projects. It is about how long it takes for those approvals to go through because sometimes there are different dimensions of that particular decision done across states. Also the private and public pieces are other dimensions that are there, which are healthy. They help you to have the private investment side with the public investment side. So, you get a better optimisation of resources in a different look of how that’s done. So, it is positive.

If there are certain land restrictions, then we have to develop a technology to allow footprints to be smaller and more compact. So, if you look at air-insulated switchgears, they can take about 10 times the space of what gas insulator switchgear does. That technology development, which we are developing here in India, also helps to address those kinds of needs.

Secondly from a renewable power standpoint in India, it’s a very difficult situation that demands for power in India is incredible. When you look at this 12th Five Year Plan, there is almost 20 gigawatts of solar power alone that’s part of that plan. It’s a huge amount of solar power. So, a real challenge from an overall geographic and logistic standpoint will be to make that happen.

However, the Indian government seems to be dedicated to make that happen. The industry has to come together. Companies like ABB will help to offer technology. We talked about renewable energies, but if you look at Co2 reduction, it’s the ultimate alternative fuel. So, whether it’s our drive systems, transmission systems, a lot of these are dedicated to how you really save power. If you can save power and you don’t have to generate it again, then ultimately, that’s the best way to address Billy Noble’s question here.

From an ABB standpoint, almost everything that was sold in China was produced by us. In fact, we have been capacity-constrained in China since 2009. Since we look at China as an export hub, from a strategic standpoint, we have been focused on much more than ever in the last 18 months. So, when it comes to qualifications of our products from China into India or from China into United States or China into Europe, we really have a rapid program to make that happen. So, I am very confident that we can be competitive on a global scale.

2011年10月7日星期五

Eight workers sent to hospital in Regina refinery explosion

Shaken by an explosion that some described as a massive fireball, workers huddled Thursday in groups in the fields surrounding the Consumers' Co-operative Refineries Ltd. in north Regina.

Ten construction workers were injured in the explosion. Eight were taken to hospital to be treated for burns, two were treated at the site. The explosion and fire broke out shortly after 2 p.m., said Gilbert Le Dressay, the refinery's manager of safety, environment and training and the incident commander.

"The situation is under control and there is no immediate danger to the people on site and/or the community, but unfortunately when the incident happened, we did have 10 injuries that we've accounted for right now," he told reporters.

At mid-afternoon, he didn't know the severity of the injuries. A foreman for Chemco electrical contractors, who declined to give his name, described the massive explosion.

"The explosion went up about 250 feet in the air - it was a huge fireball," he said. "I was about 300 feet away . . . I'm composing myself now. You can still see the marks on the red crane where the fireball hit."

He said Chemco had 250 employees on site.

"I notified everybody by radio that there was a big explosion on the unit and everybody got out," he said. "Your biggest fear is that you get everybody out safely."

Between 400 and 450 refinery employees and close to 1,000 contractors were working in the area.

Large clouds of black smoke poured from the refinery and spread for kilometres until the fire was under control by 2: 50 p.m.

A leak in a unit that produces diesel caused the release of diesel fuel and hydrogen gas, which ignited.

Cameron Keller, an insulator with Fulleraustin, a subcontractor for CCRL, was working a couple of units away from the site of the explosion when he heard popping sounds.

"It sounded like a cap popping off a beer bottle and then all of a sudden there was tons of black smoke and big waves of fire going straight up," said Keller, dressed in blue coveralls with fluorescent yellow tape and a hardhat while sitting in a field across from the refinery.

"The alarms went off and we all ran out. We were two plants away and we didn't feel the heat, but we had some guys in Unit 11 and they felt the heat right above them."

The explosion occurred in an older area of the refinery, which is being revamped.

"This is an area where we're replacing equipment, but this equipment is still monitored and repaired as normal - it's inspected and maintained, so we don't know the cause of the leak," Le Dressay said.

The unit will be closed until the cause is determined.

Vic Huard, vice-president of corporate affairs at Federated Co-operatives Ltd., said there was no danger to the public and no residential areas had to be evacuated.

"At ground level, there is no toxic cloud involved; there's no toxin danger to the public downwind - we can state that without fear of contradiction," Huard said.