Manufacturing Bits: Dec. 3

Animal robots in London; fusion plasma reactors; 2D nanosheets.


Animal robots invade London

The London Science Museum will premiere U-CAT, an underwater robot turtle designed to penetrate shipwrecks. In the exhibit, the museum will also showcase several robots that resemble an eel, bat, cheetah cub, tumbleweed, tuna, salamander and other creatures.

Meanwhile, built by the Centre for Biorobotics at Tallinn University of Technology, U-CAT’s locomotion principle is similar to sea turtles. It has four flippers, enabling the system to swim forward and backward, up and down, and turn on a spot in all directions.

The robot carries an onboard camera. The video footage can be later used to reconstruct an underwater site. U-CAT is part of a European-funded research project called ARROWS. The project is developing low-cost autonomous underwater vehicle technologies to reduce the cost of archaeological operations.

U-CAT is an underwater robot turtle (Source: Tallinn University of Technology)

U-CAT is an underwater robot turtle (Source: Tallinn University of Technology)

These robots will be tested in the Mediterranean Sea and in the Baltic Sea. Today’s underwater robots are generally used in the oil and gas industry and in defense, but these systems are too big and expensive to be used for diving inside shipwrecks. Shipwrecks are currently explored by divers, but this is also expensive and dangerous.

U-CAT is designed with the purpose of offering an affordable alternative to human divers. “Conventional underwater robots use propellers for locomotion. Fin propulsors of U-CAT can drive the robot in all directions without disturbing water and beating up silt from the bottom, which would decrease visibility inside the shipwreck,” said Taavi Salumäe, the designer of the U-CAT concept and researcher at Tallinn University of Technology, on the university’s Web site.

Fusion plasma reactors

The Foundation for Fundamental Research on Matter (FOM) is investigating the formation of various new carbon nanostructures. Researchers are using extreme plasma fluxes up to four orders of magnitude larger than conventional plasma-enhanced chemical vapor deposition (PECVD) processing.

FOM is making use of a linear plasma generator. The generator, dubbed the Pilot-PSI, was constructed to study the production and transport of hydrogen plasma at flux densities that are required for the Magnum-PSI. Meanwhile, the Magnum-PSI itself is a facility capable of creating the plasma conditions near the wall of the future fusion reactor ITER. An international fusion project, ITER hopes to demonstrate the technical feasibility of fusion as a source of energy. The fusion reactor ITER is designed to generate 10 times as much power from fusion than the reactor itself.

Meanwhile, plasmas, or hot charged gases, are already used to produce nanostructures. FOM has found that nanostructures, such as graphene and carbon nanotubes, can be developed under more extreme conditions than previously thought. Such plasmas are 10,000 times more intense than normally used for the construction of nanomaterials.

Making carbon nanostructures via plasma (Source: K.Bystrov/DIFFER)

Making carbon nanostructures via plasma (Source: K.Bystrov/DIFFER)

Rearchers exposed various materials, such as tungsten, molybdenum and graphite, to a plasma with a carbon supply. In doing so, they discovered several exotic carbon nanostructures–multi-walled or extra long nanotubes; cauliflower structures; and layers of graphene. “It was most surprising that an enormous particle bombardment like that which occurs on the edge of a fusion reactor can yield such delicate structures,” said researcher Kirill Bystrov, on FOM’s Web site. “Our interest is in demonstrating that you can allow interesting processes to occur in environments 10,000 times more intense than you would expect.”

Greg De Temmerman at the FOM Institute DIFFER, added: “We set up these experiments to investigate what happens with the wall materials in future fusion reactors. This research demonstrates that the conditions in Pilot-PSI and its big brother Magnum-PSI are also interesting far outside the fusion community.”

2D nanosheets

The National Institute for Materials Science (NIMS) has developed a technology to enable the oriented growth of perovskite-oxide thin films. The technology enables two-dimensional nanosheets or “patterned wallpaper with a nano-level thickness,” according to researchers. Applications include MEMS, sensors and memories.

Chips and optoelectronic devices incorporated crystalline thin films based on various functional materials. Perovskite oxides, namely barium titanate, represents one such class of materials. They consist of various characteristics, such as ferroelectricity and piezoelectricity.

But control of the growth of the thin films is challenging. One method is epitaxy, which is limited and costly, according to researchers. To solve the problem, NIMS has devised a library of inorganic nanosheets, which are graphene-like substances.

From the library, the group selected three types of oxide nanosheets. Then, researchers assembled them on the surface of a glass or other substrate using a solution process. This, in turn, formed an ultra-thin seed layer with a thickness around 1nm. A thin layer of perovskite-type oxide was deposited on the seed layer by a vapor-phase process.

As a result, researchers succeeded in growing thin films. They were also able to control the orientations. And they also matched the two-dimensional lattice of the nanosheets.

How to make nanosheets (Source: NIMS)

How to make nanosheets (Source: NIMS)