Lifeboat Foundation

Scientists have recently explored the unique properties of nonlinear waves to facilitate a wide range of applications including impact mitigation, asymmetric transmission, switching and focusing. In a new study now published on Science Advances, Bolei Deng and a team of research scientists at Harvard, CNRS and the Wyss Institute for Biologically Inspired Engineering in the U.S. and France harnessed the propagation of nonlinear waves to make flexible structures crawl. They combined bioinspired experimental and theoretical methods to show how such pulse-driven locomotion could reach a maximum efficiency when the initiated pulses were solitons (solitary wave). The simple machine developed in the work could move across a wide range of surfaces and steer onward. The study expanded the variety of possible applications with nonlinear waves to offer a new platform for flexible machines.

Flexible structures that are capable of large deformation are attracting interest in bioengineering due to their intriguing static response and their ability to support elastic waves of large amplitude. By carefully controlling their geometry, the elastic energy landscape of highly deformable systems can be engineered to propagate a variety of nonlinear waves including vector solitons, transition waves and rarefaction pulses. The dynamic behavior of such structures demonstrate a very rich physics, while offering new opportunities to manipulate the propagation of mechanical signals. Such mechanisms can allow unidirectional propagation, wave guiding, mechanical logic and mitigation, among other applications.

In this work, Deng et al. were inspired by the biological retrograde peristaltic wave motion in earthworms and the ability of linear elastic waves to generate motion in ultrasonic motors. The team showed the propagation of nonlinear elastic waves in flexible structures to provide opportunities for locomotion. As proof of concept, they focused on a Slinky – and used it to create a pulse-driven robot capable of propelling itself. They built the simple machine by connecting the Slinky to a pneumatic actuator. The team used an electromagnet and a plate embedded between the loops to initiate nonlinear pulses to propagate along the device from the front to the back, allowing the pulse directionality to dictate the simple robot to move forward. The results indicated the efficiency of such pulse-driven locomotion to be optimal with solitons – large amplitude nonlinear pulses with a constant velocity and stable shape along propagation.

Also could do a magnonic fusion reactor.

Magnetic Islands

But there may be a way to force the plasma into doing what we want more predictably and efficiently, as detailed in a new theoretical paper published in the journal Physics of Plasmas.

Continue reading “Physicists Discover New Trick to Stabilize Fusion Reactors” »

Circa 2019

Special Relativity. It’s been the bane of space explorers, futurists and science fiction authors since Albert Einstein first proposed it in 1905. For those of us who dream of humans one-day becoming an interstellar species, this scientific fact is like a wet blanket.

Continue reading “You Could Travel Through a Wormhole, But It’s Slower Than Space, Say Scientists” »

The iconoclastic researcher and entrepreneur wants more attention for his big ideas. But so far researchers are less than receptive.

Metamaterials, which are engineered to have properties not found in nature, have long been developed and studied because of their unique features and exciting applications. However, the physics behind their thermal emission properties have remained unclear to researchers—until now.

In a paper published in Physical Review Letters, Sheng Shen, an associate professor in Carnegie Mellon’s department of mechanical engineering, and his student Jiayu Li, a Ph.D. candidate, have created a new scale law to describe the thermal emission from metasurfaces and metamaterials.

“With this new scale law uncovering the underlying physics behind the collective thermal emission behavior of metamaterials, researchers could easily utilize existing design and optimization tools to achieve desired thermal emission properties from metamaterials, instead of blindly searching for the best solution through mapping the entire design space,” Li said.

In the summer of 2010, I had the opportunity to be part of the team that designed and built the first passive freezer that we’d ever heard of. The idea was simple, we create a well-insulated room and stack several thousand 2-liter bottles full of salt water along the walls. In the winter, we open hatches in the ceiling and everything freezes. At the end of the winter, we close the hatches and it stays at about 25°F for the whole year.

The team of students, led by physics teacher Tom Tailer ran some calculations to make sure the physics added up and calculated that we needed about 3000 bottles and about 18 inches of foam insulation on the walls and ceiling for good performance. We built the structure and insulated it using waste styrofoam, ground-up using a modified leaf shredder.

Zeno’s paradox stumped philosophers, mathematicians, and intellectuals for millennia. It took physics to finally solve it.

O,.o circa 2012.

An apparatus or structure is proposed for generating high-frequency gravitational waves (HFGWs) between pairs of force–producing elements by means of the simultaneous production of a third time derivative of mass motion of the pair of force–producing elements. The elements are configured as a cylindrical array in the proposed structure and are activated by a radiation wavefront moving along the axis of symmetry of the array. The force-producing elements can be micro-electromechanical systems or MEMS resonators such as film-bulk acoustic resonators or FBARs. A preferred cylindrical array is in the form of a double helix and the activating radiation can be electromagnetic as generated by microwave transmitters such as Magnetrons. As the activating radiation wavefront moves along the axis of the structure it simultaneously activates force elements on opposite sides of the structure and thereby generates a gravitational wave between the pair of force elements. It is also indicated that the Earth is completely transparent to the HFGWs. Thus a sensitive HFGW detector, such as the Li-Baker under development by the Chinese, can sense the generated HFGW at an Earth-diameter distance and could, in theory, be a means for implementing transglobal HFGW communications.

The Newtonian laws of physics explain the behavior of objects in the everyday physical world, such as an apple falling from a tree. For hundreds of years Newton provided a complete answer until the work of Einstein introduced the concept of relativity. The discovery of relativity did not suddenly prove Newton wrong, relativistic corrections are only required at speeds above about 67 million mph. Instead, improving technology allowed both more detailed observations and techniques for analysis that then required explanation. While most of the consequences of a Newtonian model are intuitive, much of relativity is not and is only approachable though complex equations, modeling, and highly simplified examples.

In this issue, Korman et al.¹ provide data from a model of the second gas effect on arterial partial pressures of volatile anesthetic agents. Most readers might wonder what this information adds, some will struggle to remember what the second gas effect is, and others will query the value of modeling rather than “real data.” This editorial attempts to address these questions.

The second gas effect² is a consequence of the concentration effect³ where a “first gas” that is soluble in plasma, such as nitrous oxide, moves rapidly from the lungs to plasma. This increases the alveolar concentration and hence rate of uptake into plasma of the “second gas.” The second gas is typically a volatile anesthetic, but oxygen also behaves as a second gas.⁴ Although we frequently talk of inhalational kinetics as a single process, there are multiple steps between dialing up a concentration and the consequent change in effect. The key steps are transfer from the breathing circuit to alveolar gas, from the alveoli to plasma, and then from plasma to the “effect-site.” Separating the two steps between breathing circuit and plasma helps us understand both the second gas effect and the message underlying the paper by Korman et al.¹