Applied Physics

Researchers have developed what they are billing as the world’s lightest material. With a density of 0.9 mg/cc, it is about one hundred times lighter than Styrofoam™.  The new material redefines the limits of lightweight materials because of its unique “micro-lattice” cellular architecture, they say - consists of 99.99 percent air by designing the 0.01 percent solid at the nanometer, micron and millimeter scales.  The material’s architecture allows unprecedented mechanical behavior for a metal, including complete recovery from compression exceeding 50 percent strain and…

Loudspeakers have improved a lot in the last 50 years but one pesky issue has remained; dead spots.    Modern oudspeakers can be designed to deliver the full frequency range of audible sound but it is difficult to achieve a smooth frequency output in all directions. Dead spots are caused by deconstructive interference as a result of radiating sound waves overlapping and cancellng each other out. This often happens when the sound is radiating from two or more sources, like in the mid-frequency ranges where both the 'woofer' and 'tweeter' loudspeaker cones are both active. This…

Electrocrystallization, electric-field-induced phase transformation, predicts that under the influence of sufficiently high electric fields, liquid droplets of certain materials will undergo solidification, forming crystallites at temperature and pressure conditions that correspond to liquid droplets at field-free conditions. A study in the Journal of Physical Chemistry C says they have done it. The researchers set out first to explore a phenomenon described by Sir Geoffrey Ingram Taylor in 1964 in the course of his study of the effect of lightning on raindrops, expressed as changes…

Efforts have long been underway to make the Système Internationale d'unités (SI Units) more accurate. If you know your science history, SI units were devised during the French Revolution as an alternative to the British System.   And so the French Academy of Sciences was tasked with the new system and promptly got the whole thing wrong. But SI units caught on and so efforts have been ongoing to make them more accurate.  Scientists like the idea to relate all of the unit definitions to fundamental constants of nature, making them stable and universal and giving them closer links to…

We like to think some things are constant, like temperature, and they are as long as everyone agrees.  That does not mean they are accurate.  The metric system is a famous example of a flawed measurement that nonetheless became popular. Temperature is based on a chemico-physical material property, not on an unchangeable fundamental constant. Some physicists would like to change that.  They call themselves  metrologists - measurement artists who want to be as precise and change the field of worldwide temperature measurement. Today's 'kelvin' temperature definition is…

The ring-shaped stains of tiny dissolved particles, like a coffee stains from the bottom of a cup,  that develop after a liquid has evaporated hold a physics mystery - while the particles on the outside of the ring are neatly organized, chaos reigns on the inside of the ring where the particles seem to have collected in a great hurry.  The familiar dark ring that remains after a drop of coffee has evaporated develops because the particles in the liquid move towards the outer edge of the drop as the liquid evaporates. This 'coffee stain effect' is also seen in other solutions in…

In microfluidic devices, small separated droplets flow in a stream of carrier liquid. Occasionally, selected droplets have to be merged to carry out a chemical reaction, which can be greatly facilitated with the use of electric field through a process of electrocoalescence. Researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences have recently found what governs the process and how to maximize the efficiency of merging.  Small droplets in emulsions can merge much faster in the presence of an alternating electric field.  Electrocoalescence is of…

Micro-manufacturing even the "Sons of Anarchy could love - a new type of ultra-thin, self-adhesive electronic 'tattoo' that can effectively measure data about the human heart, brain waves and muscle activity.  No bulky equipment, conductive fluids or glues needed. The researchers have created what looks like a cool tattoo, but in reality it is an epidermal electronic system (EES). They have incorporated miniature sensors, light-emitting diodes, tiny transmitters and receivers and networks of carefully crafted wire filaments into their initial designs. While existing technologies…

Science 2.0 is all about making a difference in a positive way, bringing lots of people in the world together to talk with each other about science.    We're the only open science site of decent size, meaning you don't have to be famous or bring a large audience to get invited, you just sign up and write science, so participation and communication are key to the Science 2.0 concept. Some people, though, don't want to discuss science as much as advocate logical quirkiness and mathematical trickery of their own, a kind of vanity science.  So conservation of energy, the First Law…

The most prestigious journal in the field of microscopy published an article by us this year and the work also already spawned a book chapter. Apart from the work not being critical of anything and having many cute pictures, the reason for it making it into a respectable journal may be partially due to it actually being interesting: It is a computer program, but my brain’s visual center does the main work! Now you could think that such must be very inaccurate. However, I managed to prove the accuracy of the method quantitatively, so now we have a precise analysis method that uses the computer…