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Running an LED in Reverse Could Cool Future Computers

  • Magazine Article
  • TBMG-34635
Published 2019-06-01 by Tech Briefs Media Group in United States

Researchers devised a method in which running a light emitting diode (LED) with electrodes reversed was able to cool another device nanometers away. They harnessed the chemical potential of thermal radiation — a concept more commonly used to explain how a battery works.


Lighting the Gas Monkey Garage

  • Magazine Article
  • TBMG-34423
Published 2019-05-01 by Tech Briefs Media Group in United States

Gas Monkey Garage (GMG) is arguably America's most recognized hot rod shop. Founded in 2004 by charismatic serial entrepreneur Richard Rawlings, the Dallas, Texas garage is a state-of-the-art restoration and fabrication operation, well-known for turning out stunningly restored, show-stopping rare cars and hot rod creations, all under the watchful eye of millions of TV viewers each week.


LED Lighting Improves Efficiency and Imaging

  • Magazine Article
  • TBMG-34397
Published 2019-05-01 by Tech Briefs Media Group in United States

Rocket engine testing requires a lot of light since all tests are filmed with high-speed cameras to monitor performance; however, those cameras have to adjust to the bright plume from a firing engine, which would black out the rest of the image. Traditionally, that light has been provided by metal halide bulbs.


A Development of the Holographic Lighting

Hyundai Motor Company-Byoungsuk Ahn, Jinho Na, Kihong Lee
SL Corporation-Jinho Jo
Published 2019-04-02 by SAE International in United States
A signal lamp performs a function to inform the position and behavior of the vehicle. And it represents a specific design identity of the vehicle or brand identity. Recently it implements the unique three-dimensional effect while using a LED. However, a number of LEDs and complex form of the lens shape have to be applied, so results in the size, weight, cost increase. In this study, the hologram technology that is an exemplary technique for implementing the described three-dimensional image is applied. With a hologram, it is possible to reproduce a complex shape three-dimensional image by using a hologram film. Therefore the number of parts can be reduced. And it is possible to copy the film has a mass production benefits.
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Evaluation of After-Market Light Emitting Diode Headlight Bulbs

Rensselaer Polytechnic Institute-Yi-wei Liu, John Bullough
Published 2019-04-02 by SAE International in United States
Taking advantage of growing consumer interest in light emitting diode (LED) headlights, an increasing number of after-market LED replacement bulbs is available on the market. They are designed to have similar socket shapes and sizes as halogen bulbs, in order to fit into existing headlight housings. Although none of these LED replacement bulbs conform to present federal headlighting regulations, and some are labeled for "off road use" only, others claim to meet current regulations. Regardless, many different LED bulbs can be easily purchased and installed by vehicle owners, who may or may not be aware of their regulatory status. Several different LED replacement bulb kits, each designed to replace a conventional 55-W H11 halogen bulb, were purchased and tested in three different low-beam headlight units. Photometric measurements at several critical test points for headlight performance revealed that none of the resulting distributions met all of the test point photometric requirements. Some intensity values were lower than allowed minima while others exceeded allowed maxima. Photographs of the resulting beam patterns for each combination of LED bulb…
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Functional Application, Regulatory Requirements and Their Future Opportunities for Lighting of Automated Driving Systems

Lumileds-Helmut Tiesler-Wittig
Published 2019-04-02 by SAE International in United States
Automated Driving Systems (ADS) are now at start to initiate a change of the human mobility and usage of vehicles.The safe and non-disruptive integration of automated vehicles into “normal” traffic will ask for a new way of communication between the vehicles and their environment. Similar to the existing signal lights, dedicated ADS signals can play a major role in this communication, in a passive way e.g. as tail light (to be seen) or in an active mode beyond turn indicators or stop lights.Recent publications show high attention on the automation of vehicles - traffic density as well customer comfort is driving the development towards more autonomy and intense usage of human-machine interfaces to increase effectiveness of transportation. Vehicle lighting in this field will take a natural functionality - both to see and to be seen needs to be updated to the future needs of the application. Especially during the decade of a mixed traffic situation, lighting needs to take more communication functionality than before. As most of human sensing is based on visual recognition, lighting…
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A Study of ECN ‘Spray B’ in a Light-Duty Optically Accessible Diesel Engine Based on High-Speed Imaging with LED Retro-Reflection

University of Duisburg-Essen-Ming Zhao, Sebastian Kaiser
Published 2019-04-02 by SAE International in United States
The Diesel-type three-hole Spray B (injector 211201) of the Engine Combustion Network (ECN) was used in a single-cylinder light-duty optically-accessible Diesel engine. A simple optical method was developed to quasi-simultaneously image both liquid and gas phase of the fuel spray as well as combustion at kHz rates by retro-reflection of pulsed LED light from the fire deck. From the images, liquid penetration length, fuel vapor penetration, spray dispersion angle, ignition delay, flame luminosity, and ignition location were determined. Wide-field imaging allowed for studying the nozzle hole-to-hole variation. In addition to a variation of ambient temperature and density to achieve the standard ECN condition, a variation of fuel rail pressure and swirl ratio was also investigated, under both non-reacting and reacting conditions. The results show physically reasonable variations with different operating conditions. At the same bulk temperature but a higher swirl ratio, the liquid length behaves slightly differently for different jets near the standard ECN condition; ignition occurs slightly later and temporally - but not spatially - more scattered and farther downwind in the swirl direction.…
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Influence of LED Spectral Characteristics on Glare Recovery

Rensselaer Polytechnic Institute-Nicholas Skinner, John Bullough
Published 2019-04-02 by SAE International in United States
Headlight glare is a major concern of the driving public. In the past couple of years there have been concerns expressed about the use of light emitting diode (LED) lighting technologies and possible impacts LEDs may have on people, including circadian disruption, retinal hazards, and glare. Under typical use cases, vehicle headlight exposures are insufficient to cause circadian disruption or retinal damage, but can result in disability and discomfort glare, as well as glare recovery. In general, white LEDs used for illumination have greater short-wavelength content than halogen lamps used in many headlights, and short wavelengths have been implicated in visual discomfort from bright lights at night. Previous literature is inconsistent regarding whether the spectral (color) content of a glare source affects the amount of recovery time needed to see objects, following exposure to a bright light such as a vehicle headlight. Warm and cool white LEDs were used as glare sources in the present study. They were energized and exposed to study participants at one of two illuminances (low, high) for either 3 or…
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Impacts of Flashing Emergency Lights and Vehicle-Mounted Illumination on Driver Visibility and Glare

Rensselaer Polytechnic Institute-John Bullough, Nicholas Skinner, Mark Rea
Published 2019-04-02 by SAE International in United States
Flashing emergency lights on police cars, fire trucks, and ambulances need to be bright enough to alert otherwise unaware drivers about their presence on and near the roadway. Anecdotal evidence suggests that public safety agencies select emergency lighting systems with red or blue flashing lights based on their apparent brightness, with brighter lights judged as "better." With the advent of light emitting diodes (LEDs), emergency flashing lights are brighter and produce more highly saturated colors, thereby causing greater discomfort and disability glare. As a result, first response workers are at higher risk for being injured or killed in vehicle crashes because approaching drivers cannot see them. In the present study, participants viewed red and blue flashing lights on a scale model police vehicle, conforming to present recommended practices for emergency lights. Lights varied in intensity and optical power (intensity × duration). Participants were asked to view the scale model police vehicle and identify whether a police officer figure was standing beside the vehicle. In some trials, white LED sources were energized, providing low-level illumination on…
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Automotive Engineering: April 2019

  • Magazine Article
  • 19AUTP04_18
Published 2019-04-01 by SAE International in United States

Volvo Cars has set one of the industry's most ambitious engineering goals: to have zero traffic fatalities in any of its new models beginning in 2020. It also aims to have one-third of its new-vehicle range be capable of SAE Level 4 autonomous operation by 2025. First to arrive with Level 4 capability will be the next-generation XC90 due in 2021.

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