Smaller and Less Energy Intensive Infrared Cameras


Thermogram (infrared image) of a small dog, with Fahrenheit temperature scale. Approximate Celsius scale was added later by Wikipedia. (Photo credit: Wikipedia)

Thermogram (infrared image) of a small dog, with Fahrenheit temperature scale. Approximate Celsius scale was added later by Wikipedia. (Photo credit: Wikipedia)

Infrared sensors can be employed in a wide range of applications, such as driver assistance systems for vehicles or thermography for buildings.

A new camera is providing a test bed for development of new products that use these detectors.

We want it cozy and warm in our homes when the thermometer outside gets down into the minus area. Especially with older buildings, however, the money we pay for heat ends up out the window. The fault lies hidden in incorrect insulation, or at spots around windows or ceiling joints that are not sealed. These weak points cannot be perceived from outside – unless you are viewing the building though the lens of an infrared camera. This type of camera is equipped with specialized sensors that distinguish the temperature differences of the building. Thermal bridges, where the heat penetrates faster to the outside, become immediately visible in these thermo- graphic images of buildings. The only catch: you need detectors that are highly sensitive in the far-infrared region to detect very small temperature differences. However, these detectors  need to be permanently cooled to a frosty -310 degrees Fahrenheit (-190° C). The cameras are very large, heavy, and consume a lot of energy as a result of this additional cooling.

Instant images on the PC

Scientists of the Fraunhofer Institute for Microelectronic Circuits and Systems IMS are developing infrared sensors for the far-infrared region that also operate at room temperature. A prototype camera at the Institute in Duisburg, Germany, will likely simplify product development based on these room-termperature detectors in future. “It is very time-consuming and expensive to create an image from a new detector. The sensor must first be adapted to the given camera model. We want to reduce this effort by offering a suitable camera as a testing platform for our detectors that generates images on a PC immediately,” explains Dr. Dirk Weiler from the Fraunhofer IMS.

The EVAL-IRFA camera doesn’t just prepare the infrared photo material faster. While commercially available infrared cameras have integreated image processing that typcially sharpens temperature edges or smoothes surfaces, the model from the Duisburg researchers presents a true image of every pixel. While it makes sense to enhance the images during regular operations later on, doing so during the R&D phase is counter- productive. The performance and operation can only be evaluated and adapted to a given application with the help of the raw detector data. “Since our customers come from very different application areas, they often times have very specific requirements for the sensor – in relation to the optical or temperature resolutions, for example,” explains Weiler. “If we tweek one or the other adjustment during the development phase here, the customer can immediate check the result in the actual image using our camera.”

The researchers in Duisburg are looking forward to presenting their camera during Sensor & Test in Nuremberg, from 3-5 June this year. The goal is to introduce room-temperature IR detectors into applications faster. Weiler is certain the demand is there: “Our technology opens up innovations especially for mobile applications, since it leads to smaller, lighter, and more energy-efficient camera systems.” This is of interest not just in themography for buildings. IR cameras installed as part of driver assistance systems could improve road safety, since people and animals on unlighted roadways can be detected at large distances – without high beams blinding oncoming traffic. Infrared cameras could also be valuable in building surveillance or monitoring production machinery.

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Highly Efficient Broadband Terahertz Radiation from Metamaterials


A team led by Ames Laboratory physicists demonstrated broadband, gapless terahertz emission (red line) from split-ring resonator metamaterials (background) in the telecomm wavelength. The THz emission spectra exhibit significant enhancement at magnetic-dipole resonance of the metamaterials emitter (shown in inset image). This approach has potential to generate gapless spectrum covering the entire THz band, which is key to developing practical THz technologies and to exploring fundamental understanding of optics.

The THz generation can be tailored simply by tuning the size of the meta-atoms in the metamaterial

Scientists at the U.S. Department of Energy’s Ames Laboratory have demonstrated broadband terahertz (THz) wave generation using metamaterials. The discovery may help develop noninvasive imaging and sensing, and make possible THz-speed information communication, processing and storage. The results appeared in the Jan. 8 issue of Nature Communications.

Terahertz electromagnetic waves occupy a middle ground between electronics waves, like microwave and radio waves, and photonics waves, such as infrared and UV waves. Potentially, THz waves may accelerate telecom technologies and break new ground in understanding the fundamental properties of photonics. Challenges related to efficiently generating and detecting THz waves has primarily limited their use.

Traditional methods seek to either compress oscillating waves from the electronic range or stretch waves from the optical range. But when compressing waves, the THz frequency becomes too high to be generated and detected by conventional electronic devices. So, this approach normally requires either a large-scale electron accelerator facility or highly electrically-biased photoconductive antennas that produce only a narrow range of waves.

To stretch optical waves, most techniques include mixing two laser frequencies inside an inorganic or organic crystal. However, the natural properties of these crystals result in low efficiency.

So, to address these challenges, the Ames Laboratory team looked outside natural materials for a possible solution. They used man-made materials called metamaterials, which exhibit optical and magnetic properties not found in nature.

Costas Soukoulis, an Ames Laboratory physicist and expert in designing metamaterials, along with collaborators at Karlsruhe Institute of Technology in Germany, created a metamaterial made up of a special type of meta-atom called split-ring resonators. Split-ring resonators, because of their u-shaped design, display a strong magnetic response to any desired frequency waves in the THz to infrared spectrum.

Ames Laboratory physicist Jigang Wang, who specializes in ultra-fast laser spectroscopy, designed the femto-second laser experiment to demonstrate THz emission from the metamaterial of a single nanometer thickness.

“The combination of ultra-short laser pulses with the unique and unusual  properties of the metamaterial generates efficient and broadband THz waves from emitters of significantly reduced thickness,” says Wang, who is also an associate professor of Physics and Astronomy at Iowa State University.

The team demonstrated their technique using the wavelength used by telecommunications (1.5 microns), but Wang says that the THz generation can be tailored simply by tuning the size of the meta-atoms in the metamaterial.

“In principle, we can expand this technique to cover the entire THz range,” said Soukoulis, who is also a Distinguished Professor of physics and astronomy at Iowa State University.

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New Bosch system stops the engine when the vehicle is traveling at speed, helping cut fuel consumption by 10 percent


Combustion engines runs needlessly about 30 percent of the time

With its new start-stop coasting function, Bosch enables drivers of vehicles with combustion engines to travel in zero-emission, noise-free, and low-resistance mode over large parts of their journey. This innovative technology stops the engine when the vehicle is in motion, so that it does not consume any fuel. Whenever the vehicle can maintain its speed simply by rolling – for instance on a gentle incline – the engine is stopped. As soon as the driver touches the gas or brake pedal, the engine starts up again.

Tests carried out by Bosch have shown that the combustion engines runs needlessly about 30 percent of the time, meaning that the vehicle could simply coast for about a third of every journey. Although these phases are not taken into account in the New European Driving Cycle (NEDC), under real traffic conditions the function will give drivers a roughly 10 percent fuel saving. “The start-stop coasting function is affordable, can be combined with any type of combustion engine, and substantially reduces fuel consumption,” says Dr. Rolf Bulander, member of the board of management of Robert Bosch GmbH.

Much of what makes the system innovative is its enhanced software and the use this makes of existing sensor data. Furthermore, the start-stop starter has been configured to cope with greater loads and to deliver faster restarts. In other respects, the system requires few additional components and can be integrated in just about any vehicle in the world. Whether they drive diesel-powered cars in Europe, gasoline models in North America, or CNG-powered vehicles in Asia, drivers everywhere stand to benefit from the new technology – as does the environment. After all, reduced fuel consumption also means lower CO2 emissions. In Germany, some three million new vehicles were sold in 2012. According to statistics, the annual average distance driven is around 11,500 kilometers. If every new car were equipped with the coasting system and emitted just ten grams less CO2 per kilometer as a result, the theoretical annual reduction in CO2 would amount to over 30,000 metric tons.

Soon everybody will be coasting

Today, thanks to double-clutch transmissions, some vehicles already have a “light” version of the coasting system on board. As soon as the drivers take their foot off the gas pedal, the system switches the engine to idle. While this means the vehicle is doing no more than rolling, it is still consuming fuel in order to keep the engine ticking over. Bosch start-stop systems, which have enjoyed success all over the world, stop the vehicle’s engine altogether. The first generation of the system stops the engine only when the vehicle is completely stationary, while the enhanced start-stop system cuts the engine as soon as the vehicle is coasting to a halt – for instance at a red light. In contrast, as soon as the driver’s foot is off both the gas and the brake pedal, vehicles equipped with the new start-stop coasting function stop the engine while the vehicle is in motion. That saves even more fuel. And because the engine is disengaged, the vehicle can coast for longer than it could with an overrun fuel cutoff system, for example.

“Bosch is confident that start-stop coasting will soon become an everyday feature in cars – just like air conditioning,” says Bulander. Bosch is embedding fuel-saving functionality in many of its innovative products. One example is eClutch, which makes it easy to offer the coasting function even in vehicles with manual transmissions. As soon as a coasting phase is possible, eClutch decouples automatically and the engine is stopped. The coasting function is also available as an add-on for the Bosch entry-level hybrid, the boost recuperation system, to help it save even more fuel. Equipped with a more powerful generator and a compact lithium-ion battery, the 48-volt hybrid saves around 15 percent of fuel through electrification alone. In real traffic conditions, and fitted with the coasting function that shuts down the engine, the hybrid can achieve fuel savings of an additional ten percent – or 25 percent overall. The newly developed, economical Bosch start-stop coasting function can operate with any combustion or hybrid engine and thus has a wide range of applications. That is one reason why it was voted “Most Innovative Technology” in the “Green” category at the Dinner for Winners event hosted by German auto industry journal Automobil Produktion.



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World E-Waste Map Reveals National Volumes, International Flows


Duma (Photo credit: celesteh)

By 2017, all of that year’s end-of-life refrigerators, televisions, mobile phones, computers, and other electrical and electronic products could fill a line of 40-ton trucks around three quarters of the equator. This represents a global jump of 33% in just 5 years.

The startling forecast is based on data compiled in the new online E-Waste World Map, produced by the Solving the E-Waste Problem (StEP) Initiative. This unique interactive map presents annual data from 184 countries, showing the estimated amount of electrical and electronic equipment put on the market and how much resulting e-waste is generated.

The initiative will help governments and companies plan e-waste management. Reflecting on the launch of the map, Prof. Kazuhiko Takeuchi (Director, UNU-ISP) said that “E-waste is a pressing global problem and UNU is committed through its research, and also through coordinating the StEP Initiative, to provide science-based but applied recommendations to policymakers in governments and industry. And knowing and understanding the magnitude of the issue is key.

The map shows, for example, that almost 48.9 million metric tons of used electrical and electronic products was produced last year—an average of 7 kg for each of the world’s 7 billion people. And the flood of e-waste is growing. Based on current trends, StEP experts predict that by 2017 the total annual volume will have risen by a third, to 65.4 million tons—a weight equivalent to almost 200 Empire State Buildings or 11 Great Pyramids of Giza.

“The lack of comprehensive data has made it hard to grasp the full magnitude of the problem,” said Dr. Ruediger Kuehr of UNU-ISP’s Operating Unit in Germany,SCYCLE, which leads the StEP Initiative. “This constantly updated, map-linked database showing e-waste volume by country together with legal texts will help lead to better awareness and policymaking at the public and private levels.”

The StEP E-Waste World Map database shows that in 2012, China and the United States topped the world’s totals in market volume of EEE and e-waste. China put the highest volume of EEE on the market in 2012 – 11.1 million tons, followed by the US at 10 million tons. However, the world’s two biggest economies were far apart in terms of annual e-waste per person, with each American responsible for an average 29.8 kg of hi-tech trash—almost six times higher than China’s per capita figure of 5.4 kg. For Japan the figure was 21.5 kg.

The map also provides information on e-waste rules, regulations, policies and guidance, obtained, highlighting the huge variety of requirements and lack of consistency in tackling the e-waste issue throughout the world.

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Thermoelectric materials nearing production scale

rn12_2013_Thema 4_g

The individual components of thermoelectric modules are only a few millimeters in size. They are cut from specific alloys – such as half-Heusler compounds.

More than two-thirds of the energy from primary sources like oil and gas utilized worldwide today is lost through waste heat.

Half-Heusler compounds are especially suited for manufacturing thermoelectric modules. Waste heat can be converted to electricity with them. Researchers have manufactured the alloys for the first time in kilogram quantities.

More than two-thirds of the energy from primary sources like oil and gas utilized worldwide today is lost through waste heat. Thermoelectric modules in power plants, industrial or heating systems, as well as in automobiles can make use of part of this. Thermoelectric devices harvest electrical power from temperature differences. For example, if inte- grated in the exhaust system of an auto, such a module could use the waste heat for electrical power generation and take some of the load off the alternator. “In view of the continually stricter environmental regulations of the EU, this can also be of interest to the automobile manufacturers,” according to Dr. Kilian Bartholomé from the Fraunhofer Institute for Physical Measurement Techniques IPM in Freiburg, Germany.

Even though the fundamental principles have been known for almost 200 years, most of the technology is still at an elementary stage. Efficient manufacturing processes and suitable materials are still needed. IPM has succeeded in making a big jump in development. The researchers have shown that half-Heusler compounds – which are highly suitable ma- terials for thermoelectric processes – can be produced significantly more efficiently and cost-effectively than has been previously possible. They are collaborating with Robert Bosch GmbH, the Institut für Anorganische Chemie und Analytische Chemie (Institute for Inorganic and Analytical Chemistry) at Johannes-Gutenberg-Universität Mainz, Vacuum- schmelze GmbH (vacuum smelter works) in Hanau and Isabellenhütte Heusler GmbH (smelting and foundry works) in Dillenburg on the “thermoHEUSLER” Project, supported by the German Federal Ministry of Economics and Technology (BMWi).

“Half-Heusler compounds are highly suitable for thermoelectric applications. They fulfill – almost – all of the necessary criteria,” explains Project Director Dr. Benjamin Balke, an expert in materials development at University Mainz. “The alloys consist of a wide range of materials, nickel being one, and are much more environmentally friendly than previous materials, possess good thermoelectric properties, and withstand high temperatures.”

Efficient material produced in kilogram quantities

Engineers characterize thermoelectric suitability by the “ZT value”. Industry requires ZT values greater than one. The partners in the thermoHEUSLER Project have now achieved a value of 1.2. “That corresponds to the best published values for half-Heusler compounds thus far,” says Bartholomé. It is crucial for industrial applications to attain the efficiency values during mass production that were obtained in the lab. During the thermoHEUSLER Project, Vacuumschmelze and Isabellenhütte have successfully manufactured this very ef- ficient half-Heusler material in kilogram quantities for the first time. The alloys synthesized by them result from a long tradition: the German mining engineer, chemist, and namesake of the compound, Friedrich Heusler, was head of Isabellenhütte Heusler GmbH at one time.

Thermoelectric modules are assembled from blocks a few millimeters each in size. These consist of two different types of thermoelectric materials, N-type and P-type. A critical aspect for the efficiency of the modules is the design of their electrical contacts. These need to withstand large temperature differences, yet at the same time keep the electrical resist- ance as small as possible. This is exactly what the scientists have accomplished in the thermoHEUSLER Project by using a specially developed soldering system.

Various international consortia have shown that thermoelectric modules can contribute to energy efficiency in automobiles. Prototypes have already created up to 600 watts of elec- trical power from the waste heat in the exhaust system of an auto. “There were almost 60 million motor vehicles registered in Germany at the beginning of the year. If all of these were equipped with small thermoelectric power plants in the exhaust systems, energy on the order of the amount produced annually by a nuclear power plant could theoretically be saved today,” according to Bartholomé. “That corresponds to a savings of several million tons of C02.”

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