Here’s a look at some of the latest developments in the tech world that you might have missed.
1. Water cloaking system could reduce drag
Researchers from Duke University in North Carolina have developed a water cloaking solution that could eliminate an object’s wake, reducing its drag while helping it avoid detection.
The concept is based on electromagnetic forces, and works by matching the acceleration of the surrounding water to an object’s movement. Doing this makes it theoretically possible to greatly increase the propulsion efficiency of the object, while leaving the surrounding sea undisturbed.
The use of magnetohydrodynamic forces works because when a charged particle travels through an electromagnetic field, the field creates a force on the particle. By controlling the velocity and direction of the water surrounding a moving object, the simulations show such a system can match the water’s movement within the cloak to that of the surrounding sea.
2. Soft robots with strong muscles
Researchers from Harvard University and MIT are creating soft robots that can lift objects up to 1000 times their own weight using only air or water pressure. While soft robotics has seen major research development and breakthroughs over the last decade, increased flexibility and dexterity has usually meant the use of softer materials, which in turn meant a trade-off of reduced strength and resilience.
The researchers have created origami-inspired artificial ‘muscles’ that add strength to soft robots. Each artificial muscle consists of an inner ‘skeleton’ of metal coil or folded plastic sheets. This structure is surrounded by air or fluid and sealed inside a plastic or textile bag.
The muscle moves thanks to a vacuum that is applied to the inside of the bag. This causes the bag to collapse onto the skeleton, creating tension that drives the motion. The muscle’s movement is directed entirely by the shape and composition of the skeleton, with no other power source or human input required. The engineers point out that the muscles are ‘programmable’ – designing how the skeleton folds defines the movement of the whole structure.
3. Power source inspired by the electric eel
An international team has developed a power source inspired by the electric eel, allowing the generation of 110 V just from salt and water. The research team from the University of Fribourg, University of Michigan, and University of California San Diego, focused on the electrophorus electricus, which can generate up to 600 V and 100 W to stun prey or defend itself.
The researchers reverse-engineered the animal’s electric organ, and designed a power source inspired by it, generating electricity based on the salinity difference between fresh water and salt water.
When a permeable compartment of salt water is put in contact with a similar compartment of fresh water, the salt has a natural tendency to migrate into the fresh compartment. If, however, a membrane that is more permeable to positive ions than to negative ones is placed between these two compartments, then the positive ions rush into the low salt compartment, leaving behind a negatively charged high salt compartment.
The researchers then implemented a second membrane that is more permeable to negatively charged ions. Arranging these compartments and membranes in a repeat sequence thousands of times making it possible to generate
110 V purely from salt and water.
4. Pump up the quantum dots
By electrically stimulating quantum dots, an American team has shown it is possible to amplify light from these materials opening up a new range of possible technologies such as micro-lasers.
The researchers from the Los Alamos National Laboratory (LANL) in New Mexico demonstrated that using their ‘designer’ quantum dots, they could achieve light amplification in a nanocrystal solid with direct-current electrical pumping.
The key property of the novel quantum dots is a carefully engineered particle interior in which the material’s composition is continuously varied along a radial direction.
This approach eliminates sharp steps in the atomic composition which would normally trigger Auger recombination. As a result, the engineered quantum dots feature nearly complete suppression of Auger effect’s heat loss, and this allows for redirecting the energy released by the electrical current into the light-emission channel instead of wasteful heat.
In these proof-of-principle experiments, the quantum dots were stimulated with very short (femtosecond) laser pulses used to outcompete optical gain decay caused by the Auger process. Short optical gain lifetimes create an especially serious problem in the case of electrical pumping, which is an inherently slow process as electrons and holes are injected into the quantum dot one-by-one.
These prospective devices can enable a variety of applications, from RGB laser modules for displays and projectors, to multi-wavelength micro-lasers for biological and chemical diagnostics.