Discover Top Posts Tagged with #supercritical fluids

When the Meniscus Disappears

When we first learn about states of matter, we're taught about three: solid, liquid, and gas. In a solid, atoms are held close to one another--typically, but not always, in an orderly lattice structure. In liquids and gases, atoms are free to slip, slide, bounce, and move. So what really separates a liquid from a gas? (Video and image credit: S. Mould)

#fluid dynamics #physics #science #states of matter #supercritical fluids #thermodynamics

Extraction of precious metals from electronic waste by using supercritical fluid technology

The modern world relies on a small number of precious and rare metals that are vital for the components of our electronic devices. These elements are critical to the functioning of everything from mobile phones and tablet computers to the circuitry that underpins medical scanners and military installations. The design of current technology means they cannot be substituted with another metal, each component relies on the very specific electronic properties of each in the components from which it is built.

Unfortunately, access to sources of these elements is not only limited by geology and politics, but the rarest of the metals, which are often the ones on which we rely the most are present on earth in only limited quantities. As such, every electronic device that is discarded or abandoned represents metals wasted. If there were a simple and environmentally viable means to extract those metals so that they could be reused in the next tranche of devices, then at least some of the issues of accessibility and waste might be addressed.

At this point we must turn to the pre-electronic age and the discovery of a scientific phenomenon that could come to our rescue in the modern age—supercriticality. Supercriticality is a physical characteristic of substances that are heated while being compressed and give rise to properties in the substance that are very different from the substance under normal conditions. For instance, if we heat liquid water above its boiling point the liquid is converted into gas, steam, and this evaporates into the atmosphere.

The Story of Aerogels: The Power of Porosity

The story and science behind a unique class of porous materials. What are aerogels? How are they made? And why does their unique structure give them their remarkable properties?

#Materials Science #Science #Aerogel #Porosity #Silica #Video #The Mat Sci Guy #Materials processing #Capillary action #Fluid dynamics #Supercritical fluids #Thermal conductivity

How insights into 'supercritical fluids' could help us understand the interior of the giant gas planets

The temperature and pressure inside Jupiter range from about -100°C near the edge to about 15,000°C and 50m times the Earth's atmospheric pressure in the middle. Saturn, Uranus and Neptune are similar pressure cookers. As we descend into Jupiter, we may see matter in the gas state, in the liquid state and in another, less well-known state, called the "supercritical fluid" state.

Understanding supercritical fluids is not only important for planetary scientists, it is also used in industrial processes such as power generation and food processing.

When we boil water on Earth, it changes "phase" going from a liquid to a gas state. This is due to a sudden dramatic change in the density and other properties called a "phase transition". However, if you squeezed water to 1,000 times atmospheric pressure and then heated it while keeping the pressure on, you would no longer observe boiling as such. The water molecules would whizz around with more energy, and the density would gradually go down, but there would be no sudden boiling (phase transition). This is what constitutes the supercritical fluid state – it's neither a liquid nor a gas.

Exactly how liquids and supercritical fluids behave has caused scientists to scratch their heads for decades. But new research has shed light on this problem, raising hopes that we can soon gain a much better understanding of what goes on deep inside the giant gas planets.

great news, im officially known as the weird kid who hates supercritical fluids and also protons in chemistry. life is good

#in my defense they are very hateable #chemistry #school #supercritical fluids #protons

i hate you, supercritical fluids.

#science #supercritical fluids #chemistry

Supercritical fluids are neither a gas nor a liquid. The video above shows a tube of pressurized xenon, initially below its boiling point of approximately ~16 deg C. As the temperature is raised, you see the meniscus that marks the liquid xenon disappear. At this point, the xenon has transitioned into the supercritical state. It takes up the entire tube -- like a gas -- but it is still capable of dissolving materials -- like a liquid. At the same time, though, the xenon has no surface tension because there’s no liquid/vapor interface. Toward the end of the video, the temperature gets reduced and the xenon condenses back into a liquid state. Supercritical fluids can be used in a wide variety of industrial applications, including in decaffeination, dry cleaning, and refrigeration. (Video credit: wwwperiodictableru)

#fluid dynamics #science #physics #thermodynamics #supercritical fluids