Tag Archives: #ADB

Optical Scanner Design for Adaptive Driving Beam Systems Can Lead to Safer Night Driving (Engineering)

Scientists couple adaptive driving beam technology with an electronically controllable optical scanner, enabling better road safety for drivers and pedestrians.

Car accidents are responsible for approximately a million deaths each year globally. Among the many causes, driving at night, when vision is most limited, leads to accidents with higher mortality rates than accidents during the day. Therefore, improving visibility during night driving is critical for reducing the number of fatal car accidents.

An adaptive driving beam (ADB) can help to some extent. This advanced drive-assist technology for vehicle headlights can automatically adjust the driver’s visibility based on the car speed and traffic environment. ADB systems that exist commercially are a marked improvement over manually controlled headlights, but they suffer from limited controllability. Whereas spatial light modulators, like liquid crystal pixels or digital micromirrors, can alleviate this problem, they are often expensive to implement and lead to heat loss from unutilized light power.

In a recent study published in the Journal of Optical Microsystems, researchers from Japan have come up with an alternative to conventional ADB systems: a microelectromechanical systems (MEMS) optical scanner that relies on the piezoelectric effect of electrically induced mechanical vibrations. This design consists of a thin film of lead-zirconate-titanate oxide (or PZT), which induces mechanical vibrations in the scanner in synchronization with a laser diode. The optical scanner spatially steers the laser beam to form structured light on the phosphor plate, where it is converted into bright white light. The light intensity is, in turn, modulated by the ADB controller based on the traffic, steering wheel angle, and vehicle cruising speed. University of Tokyo researcher Hiroshi Toshiyoshi, one of the authors on the paper, explains, “What is unique about this setup is that the laser beam is converted into white light at high efficiency, which reduces heating of the ADB system.”

The researchers designed the optical scanner on a single chip consisting of a bonded silicon-on-insulator wafer with the PZT layer grown on it and laminated with metal to form piezoelectric actuators. They arranged the actuators as suspensions to allow for large-angle horizontal and vertical deflections of the scanner. This, in turn, enabled two-dimensional scanning of the headlight beam. Further, they designed the modes so that they don’t react to low-frequency noise, such as from other vehicles. Their ADB system also accounts for temperature variations. Finally, they mounted the module on a vehicle and evaluated its performance for actual driving.

The researchers found that the ADB with a MEMS scanner provided the driver with better visibility, especially when it comes to seeing pedestrians. It could also reduce the glare from oncoming vehicles and reconfigure the illumination area depending on the cruising speed of the vehicle.

While this technology certainly advances drive-assist technology, it also has other potential applications in light detection and range finding, as well as inter-vehicle optical communication links, which means that the system could find use in self-driving technology of intelligent traffic systems in the future, taking us another step toward risk-free driving.

Read the original Gold Open Access article: T. Asari et al., “Adaptive driving beam system with MEMS optical scanner for reconfigurable vehicle headlight,” J. Opt. Microsys. 1(1), 014501 (2021), doi: 10.1117/1.JOM.1.1.014501

Featured image: Headlights Infographic: ADB with MEMS 2D optical scanner, based on the piezoelectric effect. © SPIE

Reference: Tomotaka Asari, Mamoru Miyachi, Yutaro Oda, Takaaki Koyama, Hiroaki Kurosu, Makoto Sakurai, Masanao Tani, Yoshiaki Yasuda, Hiroshi Toshiyoshi, “Adaptive driving beam system with MEMS optical scanner for reconfigurable vehicle headlight”, J. of Optical Microsystems, 1(1), 014501 (2021). https://www.spiedigitallibrary.org/journals/journal-of-optical-microsystems/volume-1/issue-01/014501/Adaptive-driving-beam-system-with-MEMS-optical-scanner-for-reconfigurable/10.1117/1.JOM.1.1.014501.full?SSO=1 https://doi.org/10.1117/1.JOM.1.1.014501

Provided by SPIE

Chemical Clues In Leaves Can Reveal Ash Tree Resistance to Deadly Disease (Agriculture / Botany)

Naturally occurring compounds in ash leaves could be linked to susceptibility or resistance of individual trees to the fungal disease ash dieback (ADB).

* Naturally occurring compounds in ash leaves could be linked to susceptibility or resistance of individual trees to the fungal disease ash dieback (ADB).
* Scientists at the University of Warwick and University of Exeter have identified a group of chemicals present in ash leaves which could be used as biomarkers to look for susceptibility or resistance to ADB.
* Identifying resistant trees and breeding from them could help populate the UK with ADB resistant ash.
* But, the same chemicals are used by trees to deter herbivorous insects, so selective breeding for ADB resistance could have the unintended consequence of leaving the UK ash population open to attack by invading pests.

Ash trees with ash die back. ©University of Warwick

Naturally occurring compounds in ash leaves could be linked to susceptibility of individual trees to the fungal disease ash dieback (ADB). But selecting trees with lower levels of these compounds and breeding for resistance could leave the UK ash tree population open to attack from invading insect pests in the future, according to scientists at the University of Warwick.

Secoiridoid glycosides are naturally occurring compounds found in plant leaves. Researchers from Warwick’s School of Life Sciences and Department of Chemistry and the School of Biosciences at the University of Exeter looked at the abundance and diversity of secoiridoid glycosides in the leaves of a panel of ash trees known to be resistant and samples from trees known to be susceptible to ADB from both Denmark and the UK.

Previous research had identified five compounds in the secoiridoid glycoside family that were enriched in susceptible Danish trees, but results published today in Nature Scientific Reports, show UK ash tree leaves produced 27 different individually identifiable chemicals in the group. In the paper entitled Diversity of secoiridoid glycosides in leaves of UK and Danish ash provide new insight for ash dieback management, researchers have identified particular secoiridoid glycoside compounds that could potentially be used as biomarkers for tolerance or susceptibly to ADB.

Lead author, Dr John Sidda, from the School of Life Sciences at Warwick, said: “Ash dieback is an enormous problem for the UK, as ash makes up 5.5% of British woodlands. It is the third most abundant tree species in the UK with numbers exceeding 100 million trees. Ash dieback could be devastating to the British landscape and it is estimated it could cost the UK economy up to £15 billion. Currently there is no treatment for the disease so it is vital we understand all the possible pathways to developing resistance.

“Our work shows that the small molecules in leaves could give a pretty reliable indication of a tree’s resistance as well as new insight into possible resistance mechanisms. Work is already underway to validate our results on a much larger panel of UK trees, and to identify other compounds that contribute to ash dieback resistance.”

Young ash trees suffering from ash die back. ©University of Warwick

If potential ADB tolerant ash could be identified via a rapid test, they could be selected for breeding to begin repopulating the UK countryside. However, there may be another enemy on the horizon.

The Emerald Ash Borer (EAB) beetle is an insect pest of ash which has devastated the ash tree population in North America. The pest is moving towards Europe and has already been identified in Russia and Ukraine. At the current rate of spread it will reach central Europe in 15-20 years.

Dr Sidda said: “We know that secoiridoid glycosides play a number of roles in plants, and some of these compounds act as a defence mechanism against herbivorous insect pests. In selecting trees with lower levels of these compounds in order to help protect the ash population against ADB, we may run the risk of reducing the UK’s ash trees’ natural defence against the EAB.

“However, our results indicate that there may be higher concentrations of secoiridoid glycosides in UK ash compared to Danish ash, so UK trees might be better protected against future herbivore threats such as EAB. There is also much more structural diversity of secoiridoid glycosides in the UK and Danish trees than we first thought.

“Researching and understanding these chemical compounds further will help us plan for protecting the UK ash population over the next few decades.”

Professor Murray Grant, Elizabeth Creak Chair in Food Security at the University of Warwick and report co-author said: “These results are exciting as they reveal an unexpected diversity in this class of chemical compounds between ADB susceptible and tolerant UK trees, and also between Danish and UK ash. These may act as a potential reservoir of protective compounds that contribute to tree health.

“Our ongoing research is focussed on better understanding the biology of these compounds. We are grateful to funding from UKRI that allows us to expand this study to identify other chemical markers that discriminate tolerant and susceptible trees with the goal of developing a screen for ADB tolerant ash.”

References: Murray Grant, Sidda et al., “Diversity of secoiridoid glycosides in leaves of UK and Danish ash provide new insight for ash dieback management”, Nature Scientific Reports, 2020. DOI: 10.1038/s41598-020-76140-z Link: https://doi.org/10.1038/s41598-020-76140-z

Provided by University of Warwick