New Twist on Sofa Problem That Stumped Mathematicians and Furniture Movers

Hobby 3-D Printing Leads to New Insights into Moving Sofa Problem

By Becky Oskin

Most of us have struggled with the mathematical puzzle known as the “moving sofa problem.” It poses a deceptively simple question: What is the largest sofa that can pivot around an L-shaped hallway corner?

A mover will tell you to just stand the sofa on end. But imagine the sofa is impossible to lift, squish or tilt. Although it still seems easy to solve, the moving sofa problem has stymied math sleuths for more than 50 years. That’s because the challenge for mathematicians is both finding the largest sofa and proving it to be the largest. Without a proof, it’s always possible someone will come along with a better solution.

UC Davis Scientists Boost Production in Green Cell Factories

By Becky Oskin

Cyanobacteria, one of Earth’s oldest life forms, offer a promising new source of petroleum-free fuels and chemicals. However, economies of scale currently make it challenging for these tiny creatures to compete with fossil fuels. Now, scientists at UC Davis are closer to meeting these challenges with a new advance that improves the production and growth rate of cyanobacteria.

Cyanobacteria culture

UC Davis chemist Shota Atsumi is engineering these cyanobacteria to produce biofuels. (Photo by T.J. Ushing)

Visiting scholar Masahiro Kanno, graduate student Austin Carroll and chemistry professor Shota Atsumi introduced new genetic pathways into cyanobacteria that could help make microbe-based chemical production systems smaller and easier to operate.

New Types of Structures for Cage-Like Clathrates

Compounds Could Be Basis For Devices That Turn Waste Heat Into Electricity

Cage-like compounds called clathrates could be used for harvesting waste heat and turning it into electricity. UC Davis chemists just discovered a whole new class of clathrates, potentially opening new ways to make and apply these materials.

Journal cover image

UC Davis chemists discovered a new class of clathrates that break the four-bond rule. The discovery was featured on the cover of the journal Angewandte Chemie (Wiley)

SNO+ Neutrino Detector Gets Ready For Run


SNO+ neutrino detector being filled with ultrapure water. The detector will search for neutrinos from distant supernovae and nuclear reactors. Credit: SNO+ Collaboration


Not a still from a science fiction movie, but the SNO+ neutrino detector being filled with very pure water prior to starting operations. Located over a mile underground in a mine in Ontario, Canada, the SNO+ detector consists of an acrylic sphere 12 meters in diameter filled with 800 tonnes of scintillation fluid, floating in a bath of ultrapure water surrounded by 10,000 photomultiplier tubes that will detect flashes of light from passing neutrinos.

Three Minute Egghead: Finding the Furthest, Faintest Galaxy

In the latest episode of the Three Minute Egghead podcast, UC Davis astronomer Marusa Bradac explains why she’s looking towards the beginning of time to find the furthest, faintest object in the universe, and how a gigantic lens in the sky can help.

Read the news release about this story here.

For more Three Minute Egghead podcasts, see our Soundcloud playlist here.

Physics Nobel for topological phase transitions

The 2016 Nobel Prize for Physics will be shared by David Thouless, F. Duncan Haldane and J. Michael Kosterlitz for their work on peculiar states of matter under extreme conditions. The three used advanced mathematics — specifically topology, the study of shapes — to build theoretical models of matter. Their work has practical implications for understanding superconductors, superfluids and thin magnetic films, and ultimately for new types of devices and technologies.

“This year’s Laureates opened the door on an unknown world where matter can assume strange states,” according to the Nobel Prize citation.

Calculating just how fast Usain Bolt runs

With gold medals in three sprinting events at three Olympic Games, Usain Bolt has written himself into the record books as arguably the fastest human of all time. But just how fast is the Jamaican sprinter?

Three mathematicians, Sebastian Schreiber of UC Davis, Wayne Getz of UC Berkeley and Karl Smith of Santa Rosa Junior College, show how to calculate Bolt’s maximum velocity in the 100 meters at the 2008 Beijing Olympics in their 2014 textbook, “Calculus for the Life Sciences.”

This plot shows Usain Bolt's velocity measured at 10 meter intervals.

This plot shows Usain Bolt’s velocity measured at 10 meter intervals.

LUX Dark Matter Experiment Ends Run, Still No Dark Matter

UC Davis grad student in LUX chamber

UC Davis graduate student Jeremy Mock inspecting the LUX detector before the chamber was filled with water. Credit: Matt Kapust/Sanford Lab

The Large Underground Xenon (LUX) dark matter experiment, which operates beneath a mile of rock at the Sanford Underground Research Facility in the Black Hills of South Dakota, has completed its silent search for the missing matter of the universe.

The experiment did not find a dark matter particle, but it did eliminate a wide swath of mass ranges where a Weakly Interacting Massive Particle, or WIMP, the leading theoretical candidate for dark matter, might exist, team members said.

Grounds For Concern: Is Your Coffee Consistent?

UC Davis entomologist Christian Nansen trained some high-tech analysis on coffee beans, showing that brands were not consistent in content. Photo: Kathy Garvey

UC Davis entomologist Christian Nansen trained some high-tech analysis on coffee beans, showing that brands were not consistent in content. Photo: Kathy Garvey

By Kathy Keatley Garvey

If your particular brand of coffee doesn’t seem to taste the same from week to week or month to month, you may be  right. And it’s not you, it’s the coffee beans.

Agricultural entomologist Christian Nansen of the UC Davis Department of Entomology and Nematology and four colleagues analyzed 15 brands of roasted coffee beans, purchased at an area supermarket on two dates about six months apart, and using hyperspectral imaging technology, found “they were all over the board.”

Perovskite, Potential Solar Cell Material Unsuited for Real-World Use

By Becky Oskin

Solar cells made from perovskites have sparked great excitement in recent years because the crystalline compounds boast low production costs and high energy efficiencies. Now UC Davis scientists have found that some promising compounds — the hybrid lead halide perovskites — are chemically unstable and may be unsuited for solar cells.

“We have proven these materials are highly unlikely to function on your rooftop for years,” said Alexandra Navrotsky, interdisciplinary professor of ceramic, earth, and environmental materials chemistry at UC Davis and director of the Nanomaterials in the Environment, Agriculture, and Technology (NEAT) organized research unit.