Tag Archives: outer space

Aliens wreak havoc on our personal electronics

The aliens in question are subatomic particles and the havoc they wreak is low-grade according to the scientist who was presenting on the topic at the AAAS (American Association for the Advancement of Science) 2017 Annual Meeting (Feb. 16 – 20, 2017) in Boston, Massachusetts. From a Feb. 17, 2017 news item on ScienceDaily,

You may not realize it but alien subatomic particles raining down from outer space are wreaking low-grade havoc on your smartphones, computers and other personal electronic devices.

When your computer crashes and you get the dreaded blue screen or your smartphone freezes and you have to go through the time-consuming process of a reset, most likely you blame the manufacturer: Microsoft or Apple or Samsung. In many instances, however, these operational failures may be caused by the impact of electrically charged particles generated by cosmic rays that originate outside the solar system.

“This is a really big problem, but it is mostly invisible to the public,” said Bharat Bhuva, professor of electrical engineering at Vanderbilt University, in a presentation on Friday, Feb. 17 at a session titled “Cloudy with a Chance of Solar Flares: Quantifying the Risk of Space Weather” at the annual meeting of the American Association for the Advancement of Science in Boston.

A Feb. 17, 2017 Vanderbilt University news release (also on EurekAlert), which originated the news item, expands on  the theme,

When cosmic rays traveling at fractions of the speed of light strike the Earth’s atmosphere they create cascades of secondary particles including energetic neutrons, muons, pions and alpha particles. Millions of these particles strike your body each second. Despite their numbers, this subatomic torrent is imperceptible and has no known harmful effects on living organisms. However, a fraction of these particles carry enough energy to interfere with the operation of microelectronic circuitry. When they interact with integrated circuits, they may alter individual bits of data stored in memory. This is called a single-event upset or SEU.

Since it is difficult to know when and where these particles will strike and they do not do any physical damage, the malfunctions they cause are very difficult to characterize. As a result, determining the prevalence of SEUs is not easy or straightforward. “When you have a single bit flip, it could have any number of causes. It could be a software bug or a hardware flaw, for example. The only way you can determine that it is a single-event upset is by eliminating all the other possible causes,” Bhuva explained.

There have been a number of incidents that illustrate how serious the problem can be, Bhuva reported. For example, in 2003 in the town of Schaerbeek, Belgium a bit flip in an electronic voting machine added 4,096 extra votes to one candidate. The error was only detected because it gave the candidate more votes than were possible and it was traced to a single bit flip in the machine’s register. In 2008, the avionics system of a Qantus passenger jet flying from Singapore to Perth appeared to suffer from a single-event upset that caused the autopilot to disengage. As a result, the aircraft dove 690 feet in only 23 seconds, injuring about a third of the passengers seriously enough to cause the aircraft to divert to the nearest airstrip. In addition, there have been a number of unexplained glitches in airline computers – some of which experts feel must have been caused by SEUs – that have resulted in cancellation of hundreds of flights resulting in significant economic losses.

An analysis of SEU failure rates for consumer electronic devices performed by Ritesh Mastipuram and Edwin Wee at Cypress Semiconductor on a previous generation of technology shows how prevalent the problem may be. Their results were published in 2004 in Electronic Design News and provided the following estimates:

  • A simple cell phone with 500 kilobytes of memory should only have one potential error every 28 years.
  • A router farm like those used by Internet providers with only 25 gigabytes of memory may experience one potential networking error that interrupts their operation every 17 hours.
  • A person flying in an airplane at 35,000 feet (where radiation levels are considerably higher than they are at sea level) who is working on a laptop with 500 kilobytes of memory may experience one potential error every five hours.

Bhuva is a member of Vanderbilt’s Radiation Effects Research Group, which was established in 1987 and is the largest academic program in the United States that studies the effects of radiation on electronic systems. The group’s primary focus was on military and space applications. Since 2001, the group has also been analyzing radiation effects on consumer electronics in the terrestrial environment. They have studied this phenomenon in the last eight generations of computer chip technology, including the current generation that uses 3D transistors (known as FinFET) that are only 16 nanometers in size. The 16-nanometer study was funded by a group of top microelectronics companies, including Altera, ARM, AMD, Broadcom, Cisco Systems, Marvell, MediaTek, Renesas, Qualcomm, Synopsys, and TSMC

“The semiconductor manufacturers are very concerned about this problem because it is getting more serious as the size of the transistors in computer chips shrink and the power and capacity of our digital systems increase,” Bhuva said. “In addition, microelectronic circuits are everywhere and our society is becoming increasingly dependent on them.”

To determine the rate of SEUs in 16-nanometer chips, the Vanderbilt researchers took samples of the integrated circuits to the Irradiation of Chips and Electronics (ICE) House at Los Alamos National Laboratory. There they exposed them to a neutron beam and analyzed how many SEUs the chips experienced. Experts measure the failure rate of microelectronic circuits in a unit called a FIT, which stands for failure in time. One FIT is one failure per transistor in one billion hours of operation. That may seem infinitesimal but it adds up extremely quickly with billions of transistors in many of our devices and billions of electronic systems in use today (the number of smartphones alone is in the billions). Most electronic components have failure rates measured in 100’s and 1,000’s of FITs.

chart

Trends in single event upset failure rates at the individual transistor, integrated circuit and system or device level for the three most recent manufacturing technologies. (Bharat Bhuva, Radiation Effects Research Group, Vanderbilt University)

“Our study confirms that this is a serious and growing problem,” said Bhuva.“This did not come as a surprise. Through our research on radiation effects on electronic circuits developed for military and space applications, we have been anticipating such effects on electronic systems operating in the terrestrial environment.”

Although the details of the Vanderbilt studies are proprietary, Bhuva described the general trend that they have found in the last three generations of integrated circuit technology: 28-nanometer, 20-nanometer and 16-nanometer.

As transistor sizes have shrunk, they have required less and less electrical charge to represent a logical bit. So the likelihood that one bit will “flip” from 0 to 1 (or 1 to 0) when struck by an energetic particle has been increasing. This has been partially offset by the fact that as the transistors have gotten smaller they have become smaller targets so the rate at which they are struck has decreased.

More significantly, the current generation of 16-nanometer circuits have a 3D architecture that replaced the previous 2D architecture and has proven to be significantly less susceptible to SEUs. Although this improvement has been offset by the increase in the number of transistors in each chip, the failure rate at the chip level has also dropped slightly. However, the increase in the total number of transistors being used in new electronic systems has meant that the SEU failure rate at the device level has continued to rise.

Unfortunately, it is not practical to simply shield microelectronics from these energetic particles. For example, it would take more than 10 feet of concrete to keep a circuit from being zapped by energetic neutrons. However, there are ways to design computer chips to dramatically reduce their vulnerability.

For cases where reliability is absolutely critical, you can simply design the processors in triplicate and have them vote. Bhuva pointed out: “The probability that SEUs will occur in two of the circuits at the same time is vanishingly small. So if two circuits produce the same result it should be correct.” This is the approach that NASA used to maximize the reliability of spacecraft computer systems.

The good news, Bhuva said, is that the aviation, medical equipment, IT, transportation, communications, financial and power industries are all aware of the problem and are taking steps to address it. “It is only the consumer electronics sector that has been lagging behind in addressing this problem.”

The engineer’s bottom line: “This is a major problem for industry and engineers, but it isn’t something that members of the general public need to worry much about.”

That’s fascinating and I hope the consumer electronics industry catches up with this ‘alien invasion’ issue. Finally, the ‘bit flips’ made me think of the 1956 movie ‘Invasion of the Body Snatchers‘.

Bringing home the chilling effects of outer space

They’ve invented a new type of cooling structure at Stanford University (California) which reflects sunlight back into outer space. From the Apr. 16, 2013 news item on Azonano,

A team of researchers at Stanford has designed an entirely new form of cooling structure that cools even when the sun is shining. Such a structure could vastly improve the daylight cooling of buildings, cars and other structures by reflecting sunlight back into the chilly vacuum of space.

The Apr. 15, 2013 Stanford Report by Andrew Myers, which originated the news item, describes the problem the engineers were solving,

The trick, from an engineering standpoint, is twofold. First, the reflector has to reflect as much of the sunlight as possible. Poor reflectors absorb too much sunlight, heating up in the process and defeating the goal of cooling.

The second challenge is that the structure must efficiently radiate heat (from a building, for example) back into space. Thus, the structure must emit thermal radiation very efficiently within a specific wavelength range in which the atmosphere is nearly transparent. Outside this range, the thermal radiation interacts with Earth’s atmosphere. Most people are familiar with this phenomenon. It’s better known as the greenhouse effect – the cause of global climate change.

Here’s the approach they used,

Radiative cooling at nighttime has been studied extensively as a mitigation strategy for climate change, yet peak demand for cooling occurs in the daytime.

“No one had yet been able to surmount the challenges of daytime radiative cooling –of cooling when the sun is shining,” said Eden Rephaeli, a doctoral candidate in Fan’s [Shanhui Fan, a professor of electrical engineering and the paper’s senior author] lab and a co-first-author of the paper. “It’s a big hurdle.”

The Stanford team has succeeded where others have come up short by turning to nanostructured photonic materials. These materials can be engineered to enhance or suppress light reflection in certain wavelengths.

“We’ve taken a very different approach compared to previous efforts in this field,” said Aaswath Raman, a doctoral candidate in Fan’s lab and a co-first-author of the paper. “We combine the thermal emitter and solar reflector into one device, making it both higher performance and much more robust and practically relevant. In particular, we’re very excited because this design makes viable both industrial-scale and off-grid applications.”

Using engineered nanophotonic materials, the team was able to strongly suppress how much heat-inducing sunlight the panel absorbs, while it radiates heat very efficiently in the key frequency range necessary to escape Earth’s atmosphere. The material is made of quartz and silicon carbide, both very weak absorbers of sunlight.

This new approach offers both economic and social benefits,

The new device is capable of achieving a net cooling power in excess of 100 watts per square meter. By comparison, today’s standard 10-percent-efficient solar panels generate about the same amount of power. That means Fan’s radiative cooling panels could theoretically be substituted on rooftops where existing solar panels feed electricity to air conditioning systems needed to cool the building.

To put it a different way, a typical one-story, single-family house with just 10 percent of its roof covered by radiative cooling panels could offset 35 percent its entire air conditioning needs during the hottest hours of the summer.

Radiative cooling has another profound advantage over other cooling equipment, such as air conditioners. It is a passive technology. It requires no energy. It has no moving parts. It is easy to maintain. You put it on the roof or the sides of buildings and it starts working immediately.

Beyond the commercial implications, Fan and his collaborators foresee a broad potential social impact. Much of the human population on Earth lives in sun-drenched regions huddled around the equator. Electrical demand to drive air conditioners is skyrocketing in these places, presenting an economic and environmental challenge. These areas tend to be poor and the power necessary to drive cooling usually means fossil-fuel power plants that compound the greenhouse gas problem.

“In addition to these regions, we can foresee applications for radiative cooling in off-the-grid areas of the developing world where air conditioning is not even possible at this time. There are large numbers of people who could benefit from such systems,” Fan said.

Here’s a citation and a link for the paper,

Ultrabroadband Photonic Structures To Achieve High-Performance Daytime Radiative Cooling by Eden Rephaeli, Aaswath Raman, and Shanhui Fan.  Nano Lett. [American Chemical Society Nano Letters], 2013, 13 (4), pp 1457–1461
DOI: 10.1021/nl4004283 Publication Date (Web): March 5, 2013
Copyright © 2013 American Chemical Society

The article is behind a paywall.

For anyone who might be interested in what constitutes hot temperatures, here’s a sampling from the Wikipedia List of weather records (Note: I have removed links and included only countries which experienced temperatures of 43.9 °C or 111 °F or more; I made one exception: Antarctica),

Temperature

Location

Date

North America / On Earth

56.7 °C (134 °F) Furnace Creek Ranch (formerly Greenland Ranch), in Death Valley, California, United States 1913-07-10

Canada

45.0 °C (113 °F) Midale, Yellow Grass, Saskatchewan 1937-07-05

Mexico

52 °C (125.6 °F) San Luis Rio Colorado, Sonora

Africa

55.0 °C (131 °F) Kebili, Tunisia 1931-07-07

Algeria

50.6 °C (123.1 °F) In Salah, Tamanrasset Province 2002-07-12

Benin

44.5 °C (112 °F) Kandi  ?

Burkina Faso

47.2 °C (117 °F) Dori  ?

Cameroon

47.7 °C (117.9 °F) Kousseri  ?

Central African Republic

45 °C (113 °F) Birao  ?

Chad

47.6 °C (117.7 °F) Faya-Largeau 2010-06-22

Djibouti

49.5 °C (121 °F) Tadjourah  ?

Egypt

50.3 °C (122.6 °F) Kharga  ?

Eritrea

48 °C (118.4 °F) Massawa  ?

Ethiopia

48.9 °C (120 °F) Dallol  ?

The Gambia

45.5 °C (114 °F) Basse Santa Su 2008-?-?

Ghana

43.9 °C (111 °F) Navrongo  ?

Libya

50.2 °C (122.4 °F) Zuara 1995-06

Malawi

45 °C (113 °F) Ngabu, Chikwana  ?

Mali

48.2 °C (118 °F) Gao  ?

Mauritania

50.0 °C (122 °F) Akujit  ?

Morocco

49.6 °C (121.3 °F) Marrakech 2012-07-17

Mozambique

47.3 °C (117.2 °F) Chibuto 2009-02-03

Namibia

47.8 °C (118 °F) Noordoewer 2009-02-06

Niger

48.2 °C (118.8 °F) Bilma 2010-06-23

Nigeria

46.4 °C (115.5 °F) Yola 2010-04-03

Somalia

47.8 °C (118 °F) Berbera  ?

South Africa

50.0 °C (122 °F) Dunbrody, Eastern Cape 1918

Sudan

49.7 °C (121.5 °F) Dongola 2010-06-25

Swaziland

46.1 °C (115 °F) Sidvokodvo  ?

Zimbabwe

45.6 °C (114 °F) Beitbridge,  ?

Asia

53.6 °C (128.5 °F) Sulaibya, Kuwait 2012-07-31

Bangladesh

45.1 °C (113.2 °F) Rajshahi 1972-04-30

China

49.7 °C (118 °F) Ading Lake, Turpan, Xinjiang, China 2008-08-03

India

50 °C (122 °F) Sri, Ganganagar, Rajasthan Dholpur, Rajasthan  ?

Iraq

52.0 °C (125.7 °F) Basra, Ali Air Base, Nasiriyah 2010-06-14
2011-08-02

Israel

53 °C (127.4 °F) Tirat Zvi, Israel 1942-06-21

Myanmar

47.0 °C (116.6 °F) Myinmu 2010-05-12

Pakistan

53.5 °C (128.3 °F) Mohenjo-daro, Sindh 2010-05-26

Qatar

50.4 °C (122.7 °F) Doha 2010-07-14

Saudi Arabia

52.0 °C (125.6 °F) Jeddah 2010-06-22

Thailand

44.5 °C (112.1 °F) Uttaradit 1960-04-27

Turkey

48.8 °C (119.8 °F) Mardin 1993-08-14

Oceania

50.7 °C (123.3 °F) Oodnadatta, South Australia, Australia 1960-01-02

South America

49.1 °C (120.4 °F) Villa de María, Argentina 1920-01-02

Paraguay

45 °C (113 °F) Pratts Gill, Boquerón Department 2009-11-14

Uruguay

44 °C (111.2 °F) Paysandú, Paysandú Department 1943-01-20

Central America and Caribbean Islands

45 °C (113 °F) Estanzuela, Zacapa Guatemala  ?

Europe

48.0 °C or 48.5 °C (118.4 °F or 119.3 °F) Athens, Greece or Catenuova, Italy (Catenanuova’s record is disputed) 1977-07-10 or 1999-08-10;

Bosnia and Herzegovina

46.2 °C (115.16 °F) Mosta (Herzegovina, Federation of Bosnia and Herzegovina) 1900-07-31

Cyprus

46.6 °C (115.9 °F) Letkoniko, Cyprus 2010-08-01

Italy

47 °C or 48.5 °C (116.6 or 119.3 °F) Foggia, Apulia or Catenuuova, Sicily (Catenanuova’s record is disputed) 2007-06-25 and 1999-08-10

Macedonia

45.7 °C(114.26 °F) Demir Kapija, Demir Kapija Municipality 2007-07-24

Portugal

47.4 °C (117.3 °F) Amarelja, Beja 2003-08-01

Serbia

44.9 °C (112.8 °F) Smederevska Palanka, Podunavlie Distrrict, 2007-07-24

Spain

47.2 °C (116.9 °F) Murcia 1994-07-04

Antarctica

14.6 °C (59 °F) Vanda Station, Scott Coast 1974-01-05

It seems a disproportionate number of these hot temperatures have been recorded since 2000, eh?