Screencasting with Macs and PCs

The videos below were made a few years ago to support a Science Communication and Group Project module at the School of Physics Astronomy and Mathematics at the University of Hertfordshire. The work was supported by the Institute of Physics and the HE STEM programme. I also got support from the Institute of Mathematics and its Applications. The tools are probably a bit dated now, but I hope the principles still help some students trying to get their work seen.

Students were asked to prepare a short video to present the results of their project and share it with the world. To support them, the videos below were prepared.

Students were also encouraged to prepare technical documentation and the videos for using LaTeX and structuring their documents with LaTeX were very useful.

Screencasting with a Mac

In this video we will see some tools to capture video from your screen using a Mac. The tools are Quicktime Player, MPEG Streamclip and iMovie.

Screencasting with a PC

In this video we will see some tools to capture video from your screen using a PC. The tools are CamStudio and Freemake Video Converter.

Uploading a Video to Vimeo

In this tutorial we will see how to set up an account in Vimeo and how to upload your screencast. Also you will be able to send a link to your video to you friends and other people.

Structured Documents in LaTeX

This is a video I made a few years ago to encourage my students to use better tools to write dissertations, thesis and reports that include the use of mathematics. The principles stand, although the tools may have moved on since then. I am reposting them as requested by a colleague of mine, Dr Catarina Carvalho, who I hope will still find this useful.

In this video we continue explaining how to use LaTeX. Here we will see how to use a master document in order to build a thesis or dissertation.
We assume that you have already had a look at the tutorial entitled: LaTeX for writing mathematics – An introduction

Structured Documents in LaTeX

LaTeX for writing mathematics – An introduction

This is a video I made a few years ago to encourage my students to use better tools to write dissertations, thesis and reports that include the use of mathematics. The principles stand, although the tools may have moved on since then. I am reposting them as requested by a colleague of mine, Dr Catarina Carvalho, who I hope will still find this useful.

In this video we explore the LaTeX document preparation system. We start with a explaining an example document. We have made use of TeXmaker as an editor given its flexibility and the fact that it is available for different platforms.

LaTeX for writing mathematics – An introduction

2019 Nobel Prize in Chemistry

From left: John Goodenough, M. Stanley Whittingham, and Akira Yoshino. Credits: University of Texas at Austin; Binghamton University; the Japan Prize Foundation

Originally published in Physics Today by Alex Lopatka

John Goodenough, M. Stanley Whittingham, and Akira Yoshino will receive the 2019 Nobel Prize in Chemistry for developing lithium-ion batteries, the Royal Swedish Academy of Sciences announced on Wednesday. Goodenough (University of Texas at Austin), Whittingham (Binghamton University in New York), and Yoshino (Asahi Kasei Corp and Meijo University in Japan) will each receive one-third of the 9 million Swedish krona (roughly $900 000) prize. Their research not only allowed for the commercial-scale manufacture of lithium-ion batteries, but it also has supercharged research into all sorts of new technology, including wind and solar power.

At the heart of any battery is a redox reaction. During the discharge phase, the oxidation reaction at the anode frees ions to travel through a liquid electrolyte solution to the cathode, which is undergoing a reduction reaction. Meanwhile, electrons hum through a circuit to power a connected electronic device. For the recharge phase, the redox processes reverse, and the ions go back to the anode so that it’s ready for another discharge cycle.

The now ubiquitous lithium-ion battery that powers smartphones, electric vehicles, and more got its start shortly before the 1973 oil crisis. The American Energy Commission asked Goodenough, who was then at MIT’s Lincoln Laboratory, to evaluate a project by battery scientists at the Ford Motor Company. They were looking into the feasibility of molten-salt batteries, which used sodium and sulfur, to replace the standard but outdated lead–acid batteries developed about a century earlier. But by the late 1960s, it became clear that high operating temperatures and corrosion problems made those batteries impractical (see the article by Matthew Eisler, Physics Today, September 2016, page 30).

Whittingham, then a research scientist at Exxon, instead considered low-temperature, high-energy batteries that could not only power electric vehicles but also store solar energy during off-peak hours. To that end he developed a battery in 1976 with a titanium disulfide cathode paired with a lithium metal anode. Lithium’s low standard reduction potential of −3.05 V makes it especially attractive for high-density and high-voltage battery cells. Critically, Whittingham’s design employed lithium ions that were intercalated—that is, inserted between layers of the TiS2 structure—and provided a means to reversibly store the lithium during the redox reactions.

Illustration of Whittingham's battery.
The lithium-ion battery designed by M. Stanley Whittingham had a titanium disulfide cathode and a lithium metal anode, as illustrated here. John Goodenough and Akira Yoshino improved on the technology by replacing the cathode and anode with lithium cobalt oxide and graphite, respectively. Credit: Johan Jarnestad/The Royal Swedish Academy of Sciences

Lithium’s high reactivity, however, means that it must be isolated from air and water to avoid dangerous reactions. Whittingham solved that problem by using nonaqueous electrolyte solutions that had been carefully designed and tested by other researchers in lithium electrochemistry experiments conducted a few years earlier. The proof of concept was a substantial improvement: Whittingham’s lithium-ion battery had a higher cell potential than the lead–acid battery’s—2.5 V compared with 2 V.

Whittingham’s lithium-ion battery, though, wasn’t particularly stable. After repeated discharging and recharging, whisker-like crystals of lithium would grow on the anode. Eventually the wispy threads would grow large enough to breach the barrier separating the anode from the cathode, and the battery would short-circuit or even explode.

In 1980 Goodenough didn’t solve that problem, but he did come up with a much better material for the cathode. Along with Koichi Mizushima and colleagues at Oxford University, he found that lithium cobalt oxide could be used for the cathode. As with the TiS2, the cobalt oxide structure was tightly intercalated with lithium and could thus provide the cathode with sufficient energy density. Goodenough’s insight into the relationship between the cobalt oxide structure and voltage potential resulted in better battery performance; the voltage increased from 2.5 V to 4 V. Although the new battery was an improvement over Whittingham’s design, the system still used highly reactive lithium metal as the anode, so companies couldn’t safely manufacture the batteries on a commercial scale.

The final piece of the puzzle fell into place in 1985 when Yoshino, working at the Asahi Kasei Corp, replaced the anode material with graphite. It was stable in the required electrochemical conditions and accommodated many lithium ions in graphite’s crystal structure. With Goodenough’s lithium cobalt oxide cathode and the graphite anode, Yoshino, “came up with two materials you could put together without a glove box” in a chemistry laboratory, says Clare Grey, a chemist at the University of Cambridge. Importantly, the graphite anode is lightweight and capable of being recharged hundreds of times before its performance deteriorates. Soon after, Sony teamed up with Asahi Kasei and replaced all the nickel–cadmium batteries in its consumer electronics with lithium-ion ones.

“The story of the lithium-ion battery, like so many stories about innovation, is about contributions from many sources over many years, conditioned by changing economic and social circumstances,” says Matthew Eisler, a historian of science at the University of Strathclyde in Glasgow, UK. When the 1979 oil crisis ended, the automotive industry’s interest in batteries drained, but in 1991 they were commercialized for use in cameras, laptops, smartphones, and other handheld electronics enabled by advancements in microprocessor technology.

To develop transportation that doesn’t rely on fossil fuels, the US Department of Energy in 2013 set an ambitious goal for its Joint Center for Energy Storage Research: Make a battery for electric vehicles that has five times the energy density and is one-fifth the cost of currently available batteries. DOE’s goal hasn’t been reached yet, but the program was renewed in September 2018, with dedicated funding of $120 million over the next five years. In a story on the center, Goodenough told Physics Today (June 2013, page 26), “People are working hard, and I believe the problem is solvable, but to get to the next stage, it’s going to take a little luck and some cleverness.”

Editor’s note: This post was updated at 7:15pm EDT from an earlier summary.

Orion at the Institute of Physics

via Instagram

It was great to have been able to attend a lecture at the new home of the Institute of Physics. I have been a member for almost two decades and I have even served as an officer for one of the interest groups, the Computational Physics Group is you must know.

The event was a talk by Stephen Hilton from the School of Pharmacy, UCL 3D Printing and its Application in Chemistry and Pharmacy. It was a very useful talk covering applications ranging from teaching, cost saving in chemistry labs, personalised medicine and chemistry itself.

As for the building, it was nice to finally see the end result, with a hint of brutalist architecture and some nice details such as the electromagnetic wave diagram in some of the windows, and Orion in the cealing!

The Year in Math and Computer Science

A reblog from Quanta Magazine:

Several mathematicians under the age of 30, and amateur problem-solvers of all ages, made significant contributions to some of the most difficult questions in math and theoretical computer science.

Youth ruled the year in mathematics. The Fields Medals — awarded every four years to the top mathematicians no older than 40 — went out to four individuals who have left their marks all over the mathematical landscape. This year one of the awards went to Peter Scholze, who at 30 became one of the youngest ever to win. But at times in 2018, even 30 could feel old.

Two students, one in graduate school and the other just 18, in two separate discoveries, remapped the borders that separate quantum computers from ordinary classical computation. Another graduate student proved a decades-old conjecture about elliptic curves, a type of object that has fascinated mathematicians for centuries. And amateur mathematicians of all ages rose up to make significant contributions to long-dormant problems.

But perhaps the most significant sign of youth’s rise was when Scholze, not a month after the Fields Medal ceremony, made public (along with a collaborator) his map pointing to a hole in a purported proof of the famous abc conjecture. The proof, put forward six years ago by a mathematical luminary, has baffled most mathematicians ever since.

A new Bose-Einstein condensate

Originally published here.

A new Bose-Einstein condensate


Although Bose-Einstein condensation has been observed in several systems, the limits of the phenomenon need to be pushed further: to faster timescales, higher temperatures, and smaller sizes. The easier creating these condensates gets, the more exciting routes open for new technological applications. New light sources, for example, could be extremely small in size and allow fast information processing.

In experiments by Aalto researchers, the condensed particles were mixtures of light and electrons in motion in gold nanorods arranged into a periodic array. Unlike most previous Bose-Einstein condensates created experimentally, the new condensate does not need to be cooled down to temperatures near absolute zero. Because the particles are mostly light, the condensation could be induced in room temperature.

‘The gold nanoparticle array is easy to create with modern nanofabrication methods. Near the nanorods, light can be focused into tiny volumes, even below the wavelength of light in vacuum. These features offer interesting prospects for fundamental studies and applications of the new condensate,’ says Academy Professor Päivi Törmä.

The main hurdle in acquiring proof of the new kind of condensate is that it comes into being extremely quickly.’According to our theoretical calculations, the condensate forms in only a picosecond,’ says doctoral student Antti Moilanen. ‘How could we ever verify the existence of something that only lasts one trillionth of a second?’

Turning distance into time

A key idea was to initiate the condensation process with a kick so that the particles forming the condensate would start to move.

‘As the condensate takes form, it will emit light throughout the gold nanorod array. By observing the light, we can monitor how the condensation proceeds in time. This is how we can turn distance into time,’ explains staff scientist Tommi Hakala.

The light that the condensate emits is similar to laser light. ‘We can alter the distance between each nanorod to control whether Bose-Einstein condensation or the formation of ordinary laser light occurs. The two are closely related phenomena, and being able to distinguish between them is crucial for fundamental research. They also promise different kinds of technological applications,’ explains Professor Törmä.

Both lasing and Bose-Einstein condensation provide bright beams, but the coherences of the light they offer have different properties. These, in turn, affect the ways the light can be tuned to meet the requirements of a specific application. The new condensate can produce light pulses that are extremely short and may offer faster speeds for information processing and imaging applications. Academy Professor Törmä has already obtained a Proof of Concept grant from the European Research Council to explore such prospects.

Materials provided by Aalto University. Note: Content may be edited for style and length.

Journal Reference:

1 Tommi K. Hakala, Antti J. Moilanen, Aaro I. Väkeväinen, Rui Guo, Jani-Petri Martikainen, Konstantinos S. Daskalakis, Heikki T. Rekola, Aleksi Julku, Päivi Törmä. Bose–Einstein condensation in a plasmonic lattice. Nature Physics, 2018; DOI: 10.1038/s41567-018-0109-9