France’s transport minister said Wednesday that so-called “flying taxis”—large futuristic drones capable of transporting several people—would be authorized for use on an experimental basis during the Paris Olympics.

“We are going to experiment with this world-first during the Olympic Games. It’s a technological advance that could be of use,” Patrice Vergriete told Le Parisien newspaper.

But he also dashed hopes of sports fans hoping to buzz over the City of Light to reach their destinations in July and August, saying that the terms of the authorization would be limited and not include use by the general public.

“I’m not a fan of the name ‘flying taxi’ as it’s been called,” he added before explaining the possible roles for the 18-rotor vehicles which resemble small helicopters.

He said they “could be useful as a future ambulance, so let’s be pragmatic. Let’s analyze the impact and do a cost-benefit analysis.

“There’ll be some test flights during the Games. If we see that they’re not effective and that they make too much noise, then we’ll draw conclusions,” Vergriete added.

“Flying taxis” were once a staple of science-fiction movies but are now a reality—in theory.

Manufacturers have run into regulatory and safety barriers around the world that have prevented their roll-out.

‘Greenwashing’?

Germany manufacturer Volocopter has been conducting test flights in the Paris region for several years of its two-seater VoloCity and has lobbied hard for authorization from European authorities in time for the Olympics.

The company has partnered with French airport operator ADP, the capital’s metro and bus operator RATP, and the Paris regional government.

Four landing and take-off zones have been built around the capital, including at the Charles de Gaulle airport and the smaller Le Bourget airfield, in addition to a new floating platform on the river Seine in western Paris.

In addition to regulatory hurdles, it is yet to convince French authorities of its environmental credentials or utility as a battery-powered low-carbon transport solution.

Local councilors in Paris have voted unanimously against the concept.

“It’s greenwashing in its purest form, a mode of transport created for the ultra-rich in a hurry because there’s only one space for a passenger,” deputy mayor of Paris, Dan Lert, from the French Greens party told AFP.

A petition demanding a ban has garnered around 15,000 signatures and a collective named “Flying Taxis, No Thanks” has called for a demonstration on June 21.

Volocopter says it has invested around 600 million euros ($650 million) and the group came close to bankruptcy earlier this year.

It is aiming for certification from the European Union Aviation Safety Agency (EASA) “in the autumn”, the company said last month.

With a maximum airspeed of 110 kilometers (68 miles) per hour, the VoloCity has room for a pilot and a passenger.

The Paris Olympics run from July 26-August 11, followed by the Paralympics from August 28-September 8.

© 2024 AFP

The transition from traditional 2D to 3D microfluidic structures is a significant advancement in microfluidics, offering benefits in scientific and industrial applications. These 3D systems improve throughput through parallel operation, and soft elastomeric networks, when filled with conductive materials like liquid metal, allowing for the integration of microfluidics and electronics.

However, traditional methods such as soft lithography fabrication which requires cleanroom facilities have limitations in achieving fully automated 3D interconnected microchannels. The manual procedures involved in these methods, including polydimethylsiloxane (PDMS) molding and layer-to-layer alignment, hinder the automation potential of microfluidic device production.

3D printing is a promising alternative to traditional microfluidic fabrication methods. Photopolymerization techniques like stereolithography apparatus (SLA) and digital light processing (DLP) enable the creation of complex microchannels.

While photopolymerization allows for flexible devices, challenges remain in integrating external components such as electronic elements during light-based printing.

Extrusion-based methods like fused deposition modeling (FDM) and direct ink writing (DIW) offer automated fabrication but face difficulties in printing elastomeric hollow structures. The key challenge is finding an ink that balances softness for component embedding and robustness for structural integrity to achieve fully printed, interconnected microfluidic devices with embedded functionality.

As of now, existing 3D printing technologies have not simultaneously realized 1) direct printing of interconnected multilayered microchannels without supporting materials or post-processing and 2) integration of electronic elements during the printing process.

Researchers from the Singapore University of Technology and Design’s (SUTD) Soft Fluidics Lab addressed these two significant challenges in a study appearing in Advanced Functional Materials:

1. Direct printing of interconnected multilayered microchannels

The settings for DIW 3D printing were optimized to create support-free hollow structures for silicone sealant, ensuring that the extruded structure did not collapse. The research team further expanded this demonstration to fabricate interconnected multilayered microchannels with through-holes between layers; such geometries of microchannels (and electric wires) are often required for electronic devices such as antennas for wireless communication.

2. Integration of electronic components

Another challenge is the integration of electronic components into the microchannels during the 3D printing process. This is difficult to achieve with resins that cure immediately.

The research team took advantage of gradually curing resins to embed and immobilize the small electronic elements (such as RFID tags and LED chips). The self-alignment of those elements with microchannels allowed the self-assembly of the components with the electric wirings when liquid metal was perfused through the channel.

Why is this technology important?

While many electronic devices necessitate a 3D configuration of conductive wires, such as a jumper wire in a coil, this is challenging to achieve through conventional 3D printing methods.

The SUTD research team proposed a straightforward solution for realizing devices with such intricate configurations. By injecting liquid metal into a 3D multilayered microchannel containing embedded electronic components, self-assembly of conductive wires with these components is facilitated, enabling the streamlined fabrication of flexible and stretchable liquid metal coils.

To exemplify the practical advantages of this technology, the team created a skin-attachable radio-frequency identification (RFID) tag using a commercially available skin-adhesive plaster as a substrate and a free-standing flexible wireless light-emitting device with a compact footprint (21.4 mm × 15 mm).

The first demonstration underscores this solution’s ability to automate the production of stretchable printed circuits on a widely accepted, medically approved platform. The fabricated RFID tag demonstrated a high Q factor (~70) even after 1,000 cycles of tensile stress (50% strain), showcasing stability in the face of repeated deformations and adherence to the skin. Alternatively, the research team envisions employing small, flexible wireless optoelectronics for photodynamic therapy as medical implants on biological surfaces and lumens.

“Our technology will offer a new capability to realize the automated fabrication of stretchable printed circuits with 3D configuration of electrical circuits consisting of liquid metals,” says lead author of the paper, Dr. Kento Yamagishi, SUTD.

“The DIW 3D printing of elastomeric multilayered microchannels will enable the automated fabrication of fluidic devices with 3D arrangement of channels, including multifunctional sensors, multi-material mixers, and 3D tissue engineering scaffolds,” says Associate Professor Michinao Hashimoto, SUTD principal investigator.