Here are a couple of neat papers that I came across in the last week.  (Planning to write something about multiferroics as well, once I have a bit of time.) The idea of directly extracting useful energy from the rotation of the earth sounds like something out of an H. G. Wells novel.  At a rough estimate (and it's impressive to me that AI tools are now able to provide a convincing step-by-step calculation of this; I tried w/ gemini.google.com) the rotational kinetic energy of the earth is about \(2.6 \times 10^{29}\) J.  The tricky bit is, how do you get at it?  You might imagine constructing some kind of big space-based pick-up coil and getting some inductive voltage generation as the earth rotates its magnetic field past the coil.  Intuitively, though, it seems like while sitting on the (rotating) earth, you should in some sense be comoving with respect to the local magnetic field, so it shouldn't be possible to do anything clever that way.  It turns out, though, that Lorentz forces still apply when moving a wire through the axially symmetric parts of the earth's field.  This has some conceptual contact with Faraday's dc electric generator.   With the right choice of geometry and materials, it is possible to use such an approach to extract some (tiny at the moment) power.  For the theory proposal, see here.  For an experimental demonstration, using thermoelectric effects as a way to measure this (and confirm that the orientation of the cylindrical shell has the expected effect), see here.  I need to read this more closely to decide if I really understand the nuances of how it works. On a completely different note, this paper came out on Friday.  (Full disclosure:  The PI is my former postdoc and the second author was one of my students.)  It's an impressive technical achievement.  We are used to the fact that usually macroscopic objects don't show signatures of quantum interference.  Inelastic interactions of the object with its environment effectively suppress quantum interference effects on some time scale (and therefore some distance scale).  Small molecules are expected to still show electronic quantum effects at room temperature, since they are tiny and their electronic levels are widely spaced, and here is a review of what this could do in electronic measurements.  Quantum interference effects should also be possible in molecular vibrations at room temperature, and they could manifest themselves through the vibrational thermal conduction through single molecules, as considered theoretically here.  This experimental paper does a bridge measurement to compare the thermal transport between a single-molecule-containing junction between a tip and a surface, and an empty (farther spaced) twin tip-surface geometry.  They argue that they see differences between two kinds of molecules that originate from such quantum interference effects. As for more global issues about the US research climate, there will be more announcements soon about reductions in force and the forthcoming presidential budget request.  (Here is an online petition regarding the plan to shutter the NIST atomic spectroscopy group.)  Please pay attention to these issues, and if you're a US citizen, I urge you to contact your legislators and make your voice heard.

Several people have asked me whether writing a popular-science book has fed back into my research. Nature Physics published my favorite illustration of the answer this January. Here’s the story behind the paper. In late 2020, I was sitting by … Continue reading →

This is an interesting concept, with an interesting history, and I have heard it quoted many times recently – “we get the politicians (or government) we deserve.” It is often invoked to imply that voters are responsible for the malfeasance or general failings of their elected officials. First let’s explore if this is true or […] The post The Politicians We Deserve first appeared on NeuroLogica Blog.

Pregnancy can be painful and, for some women, impossible. New technology may allow more women to have children and save the lives of prematurely born infants.

hot combs—they all obviously benefited from the jolt of electrification. But the eraser? What was so problematic about the humble eraser that it needed electrifying? 1935 patent application for an apparatus for erasing, “Hand held rubbers are clumsy and cover a greater area than may be required.” Aye, there’s the rub, as it were. Lukowski’s cone-tipped electric eraser, he argued, could better handle the fine detail. Consider the careful technique Roscoe C. Sloane and John M. Montz suggest in their 1930 book Elements of Topographic Drawing. To make a correction to a map, these civil engineering professors at Ohio State University recommend the following steps: With a smooth, sharp knife pick the ink from the paper. This can be done without marring the surface. Place a hard, smooth surface, such as a [drafting] triangle, under the erasure before rubbing starts. When practically all the ink has been removed with the knife, rub with a pencil eraser. Erasing was not for the faint of heart! A Brief History of the Eraser Where did the eraser get its start? The British scientist Joseph Priestley is celebrated for his discovery of oxygen and not at all celebrated for his discovery of the eraser. Around 1766, while working on The History and Present State of Electricity, he found himself having to draw his own illustrations. First, though, he had to learn to draw, and because any new artist naturally makes mistakes, he also needed to erase. In 1766 or thereabouts, Joseph Priestley discovered the erasing properties of natural rubber.Alamy Alas, there weren’t a lot of great options for erasing at the time. For items drawn in ink, he could use a knife to scrape away errors; pumice or other rough stones could also be used to abrade the page and remove the ink. To erase pencil, the customary approach was to use a piece of bread or bread crumbs to gently grind the graphite off the page. All of the methods were problematic. Without extreme care, it was easy to damage the paper. Using bread was also messy, and as the writer and artist John Ruskin allegedly said, a waste of perfectly good bread. Priestley may have discovered this attribute of rubber, but Edward Nairne, an inventor, optician, and scientific-instrument maker, marketed it for sale. For three shillings (about one day’s wages for a skilled tradesman), you could purchase a half-inch (1.27-cm) cube of the material. Priestley acknowledged Nairne in the preface of his 1770 tutorial on how to draw, A Familiar Introduction to the Theory and Practice of Perspective, noting that caoutchouc was “excellently adapted to the purpose of wiping from paper the marks of a black-lead-pencil.” By the late 1770s, cubes of caoutchouc were generally known as rubbers or lead-eaters. What was so problematic about the humble eraser that it needed electrifying? Luckily, there were lots of other people looking for ways to improve natural rubber, and in 1839 Charles Goodyear developed the vulcanization process. By adding sulfur to natural rubber and then heating it, Goodyear discovered how to stabilize rubber in a firm state, what we would call today the thermosetting of polymers. In 1844 Goodyear patented a process to create rubber fabric. He went on to make rubber shoes and other products. (The tire company that bears his name was founded by the brothers Charles and Frank Seiberling several decades later.) Goodyear unfortunately died penniless, but we did get a better eraser out of his discovery. Who Really Invented the Electric Eraser? Albert Dremel, who opened his eponymous company in 1932, often gets credit for the invention of the electric eraser, but if that’s true, I can find no definitive proof. Out of more than 50 U.S. patents held by Dremel, none are for an electric eraser. In fact, other inventors may have a better claim, such as Homer G. Coy, who filed a patent for an electrified automatic eraser in 1927, or Ola S. Pugerud, who filed a patent for a rotatable electric eraser in 1906. The Dremel Moto-Tool, introduced in 1935, came with an array of swappable bits. One version could be used as an electric eraser.Dremel In 1935 Dremel did come out with the Moto-Tool, the world’s first handheld, high-speed rotary tool that had interchangeable bits for sanding, engraving, burnishing, and sharpening. One version of the Moto-Tool was sold as an electric eraser, although it was held more like a hammer than a pencil. Introduction to Cataloging and the Classification of Books. She described a flat, round rubber eraser mounted on a motor-driven instrument similar to a dentist’s drill. The eraser could remove typewriting and print from catalog cards without leaving a rough appearance. By 1937, discussions of electric erasers were part of the library science curriculum at Columbia University. Electric erasers had gone mainstream. To erase pencil, the customary approach was to use a piece of bread to gently grind the graphite off the page. In 1930, the Charles Bruning Co.’s general catalog had six pages of erasers and accessories, with two pages devoted to the company’s electric erasing machine. Bruning, which specialized in engineering, drafting, and surveying supplies, also offered a variety of nonelectrified eraser products, including steel erasers (also known as desk knives), eraser shields (used to isolate the area to be erased), and a chisel-shaped eraser to put on the end of a pencil. Loren Specialty Manufacturing Co. arrived late to the electric eraser game, introducing its first such product in 1953. Held in the hand like a pen or pencil, the Presto electric eraser would vibrate to abrade a small area in need of correction. The company spun off the Presto brand in 1962, about the time the Presto Model 80 [shown at top] was produced. This particular unit was used by officer workers at the New York Life Insurance Co. and is now housed at the Smithsonian’s Cooper Hewitt. The Creativity of the Eraser When I was growing up, my dad kept an electric eraser next to his drafting table. I loved playing with it, but it wasn’t until I began researching this article that I realized I had been using it all wrong. The pros know you’re supposed to shape the cylindrical rubber into a point in order to erase fine lines. Darrel Tank, who specializes in pencil drawings. I watched several of his surprisingly fascinating videos comparing various models of electric erasers. Seeing Tank use his favorite electric eraser to create texture on clothing or movement in hair made me realize that drawing is not just an additive process. Sometimes it is what’s removed that makes the difference. - YouTube Susan Piedmont-Palladino, an architect and professor at Virginia Tech’s Washington-Alexandria Architecture Center, has also thought a lot about erasing. She curated the exhibit “Tools of the Imagination: Drawing Tools and Technologies from the Eighteenth Century to the Present” at the National Building Museum in 2005 and authored the companion book of the same title. Piedmont-Palladino describes architectural design as a long process of doing, undoing, and redoing, deciding which ideas can stay and which must go. Of course, the pencil, the eraser (electric or not), and the computer are all just tools for transmitting and visualizing ideas. The tools of any age reflect society in ways that aren’t always clear until new tools come to replace them. Both the pencil and the eraser had to be invented, and it is up to historians to make sure they aren’t forgotten. Part of a continuing series looking at historical artifacts that embrace the boundless potential of technology. An abridged version of this article appears in the April 2025 print issue as “When Electrification Came for the Eraser.” References The electric eraser, more than any object I have researched for Past Forward, has the most incorrect information about its history on the Internet—wrong names, bad dates, inaccurate assertions—which get repeated over and over again as fact. It’s a great reminder of the need to go back to original sources. As always, I enjoyed digging through patents to trace the history of invention and innovation in electric erasers. Other primary sources I consulted include Margaret Mann’s Introduction to Cataloging and the Classification of Books, a syllabus to Columbia University’s 1937 course on Library Service 201, and the Charles Bruning Co.’s 1930 catalog. Although Henry Petroski’s The Pencil: A History of Design and Circumstance only has a little bit of information on the history of erasers, it’s a great read about the implement that does the writing that needs to be erased.