My wife, Denian, died at home, on Sunday, 30 July 2023.

She was diagnosed with glioblastoma in March 2018.

The last five years have been fulfilling. She saw births of two more grandchildren. She attended wedding of our second son. She pointed to me pretty spots on our walks. Denian (庄得年) was born in Lanzhou, on 8 March 1962. Both of her parents graduated from college. She had two younger brothers.

This photo was taken in 1976, when the family lived in Jiayuguan.

#thermofact
What does the Boltzmann constant mean?

1/ Temperature has many units, among which are Kelvin and Joule. The two units covert as

1 Kelvin = 1.380649 × 10^−23 Joule

This conversion factor is called the Boltzmann constant, k.

It is analogous to

1 inch = 2.54 cm 2/ It looks silly to name an unsightly conversion factor after three great names: Joule, Kelvin, and Boltzmann.

All units are silly, but they are necessary evils.

Let's learn about the two units of temperature, Kelvin and Joule.

Kittel and Kroemer began with a 3.5 page Introduction.

“Our approach to thermal physics differs from the tradition followed in beginning physics courses. Therefore we provide this introduction to set out what we are going to do on the chapters that follow.” From Preface: “We develop methods (not original, but not easily accessible elsewhere)… We wrote the book in the first place because we were delighted by the clarity of the ‘new’ methods as compared to those we were taught when we were students ourselves.”

Lately we have heard numerous incidents that travelers are harassed by federal agents for hours at the U.S. border.

The horror stories make many of us feel so uncomfortable that we stop ALL international travels.

Stop border harassments!

The practice is too rampant.

UNCIVIL!

https://twitter.com/zhigangsuo/status/1484850804058214400

My last international travel was in January 2020, just before pandemic. I have not been subject to border harassment.

But a student in my group was interrogated about my research.

My group works on the mechanical behavior of polymers. Our work is remote from national security.

I have spent countless hours with this little book. It contains three pioneering papers in discovering thermodynamics:

Carnot (1824)
Clapeyron (1835)
Clausius (1850)

Seek enlightenment when i was young.
Relive in darkness as I get old. Carnot (1824) marks the beginning of the discovery of entropy.

Two hundred years of entropy will soon upon us.

When Carnot wrote his pamphlet, Europe was at the mighty height of the Industrial Revolution, powered by engine, steel, and coal.

He was 28.
en.wikipedia.org/wiki/Nicolas_L…

#thermofact
Thermodynamics of phase transition

1/10 This thread focuses on a simple case, which illustrates the thermodynamic method.

Make a system of one species of molecules.
Neglect change in volume.

Thus, the system has a single independent variable: energy. 2/10 Consider a system of H2O molecules and two phases, ice and water. Change in volume is small, and is neglected in this model.

Water is a phase, which can be in many states. The same is true for ice.

Water and ice can equilibrate in mixtures.

“Gelfand visited today,” Denian said, “and big professors all acted like students in front of him.”

It was in the late 1980s, when Denian worked as a secretary at Harvard Mathematics Department.

Much I know about linear algebra comes from this 185-page book.

A brilliant book. "Does the name Gelfand mean anything to you," I asked Denian today.

"He was a Russian Mathematician," she said.

"How do you know?"

"He visited Harvard Math Department."

"Do you remember anything about the visit?"

"No."

I read my tweet to her.

"That's accurate!" she said.

#threadsofpolymers
Entropy of mixing in condensed phases

1/5 When a pure substance of molecule A mixes with a pure substance of molecule B, the entropy of the mixture exceeds the sum of the entropies of the two pure substances.

The excess is called the entropy of mixing. 2/5 Molecules A and B can have different volumes. A molecule can jiggle into many shapes. For example, A can be a macromolecule, and B a solvent molecule.

Mixing is taken to change neither the volume of each molecule, not the number of shapes that each molecule can jiggle into.

I was in a subgroup meeting on zoom, and received a phone call from Gang Chen!

"I'm a free man now!" he said.

A page has just turned.

Unsure what's on the next page, but that will be for another day. With several friends we spent last few hours at Gang Chen’s home, masks on. Between answering phone calls and emails, he told us stories.

A lot to unpack.

We are back home now. I need to make dinner, and get ready for a research meeting on zoom this evening.

The Journal of Controversial Ideas has just posted its first issue. I have not read any articles in it, but have read the editorial.

The Internet has been with us for decades, but we are still learning to use it to discuss controversial ideas.
journalofcontroversialideas.org/download/artic… “freedom of thought and discussion in the universities is no longer a universally held value, even among academics.”

“why should academics be free to write and teach whatever they want, including what most people find tasteless, unnecessarily provocative, or even dangerous?”

Thank @MargaretKLewis for pointing to us the National Committee on US-China Relations. @NCUSCR

Yesterday I went online and took a look, just in time to watch the Webinar by @ryanl_hass on America’s China Strategy in an Era of Competitive Interdependence
ncuscr.org/event/adapting… It is refreshing to hear @ryanl_hass to present an American's China Strategy from confidence.

His new book, Stronger: Adapting America's China Strategy in an Age of Competitive Interdependence, is actively discussed.

Here is a YouTube video:

Thank you, @BobbyChesney, for pointing to this affidavit against Professor Gang Chen, of MIT, prepared by the Special Agent Matthew McCarthy, of the Department of Homeland Security.

wwlp.com/wp-content/upl…

In this thread, this document will be called

The McCarthy Document.

https://twitter.com/BobbyChesney/status/1350460207177084929

The McCarthy Document is the basis for the arrest of Professor Gang Chen.

This arrest is an act of a Government against an Individual.

The power asymmetry between a government and an individual is ENORMOUS.

We the people should do everything to ensure no abuse of power.

... Chen’s research at MIT has been funded by more than $19 million in grants awarded by various U.S. federal agencies.

... Chen allegedly received approximately $29 million of foreign funding...

How do academics raise money? What is the money used for?

justice.gov/usao-ma/pr/mit… "Defendant allegedly failed to disclose his work for the People’s Republic of China"

When an academic raises funding, the money goes through the university to fund research that will be published in the public domain.

It is misleading to say that he "worked" for the PRC.

Before I came to America, in August 1986, Denian and I went from Xian to Shanghai, and had our wedding in Shanghai.

Then I flew to America, and she went back to Xian.

She joined me in Boston in July 1987.

It was so long ago. It was like yesterday.

https://twitter.com/tongbingxue/status/1331488916256350208

My parents grew up in Shanghai and attended college there In the 1950s. Upon graduation, they were assigned to teach at Shanghai Jiaotong University. Around the time, the government decided to move the university and people to Xian.

Imagine moving MIT from Massachusetts to Ohio!

One hundred years of toughness

Griffith repays repeated study. Recently I noticed Section 11, in which he described an experiment on rupture of liquid.

Griffith 1921 the phenomena of rupture and flow in solids

⁦@Junsoo_twit⁩ ⁦@jasongsteck⁩ scholar.google.com/scholar?hl=en&… Here are the notes I wrote on the Griffith paper for my graduate course on fracture mechanics. The notes connect his experiments to current practice.

When writing these notes, I did not notice his experiments on rupture of liquid.

imechanica.org/node/7470