“Most of direct processes were found to have an overall cost far larger than the CO 2 removal tax, because of incomplete carbonation and insufficient properties of the reaction products. …”

.

“The accelerated weathering of olivine is the only method we are aware of to remove CO2 from the atmosphere that is viable with today’s technology, can be done at a reasonable price, and that is scalable to the gigaton level.”

.

]]>Not to clutter your list i’ll just say for completeness, https://arxiv.org/abs/1210.2390 describes the ‘Vaxjo interpretation’ .

(I think its closer to E Nelson’s Stochastic Dynamics or Bohm’s ‘quantum potential,and ‘stochastic electrodynamics’ (largely discredited, but even people at MIT still study some aspects of that..)

(There are many other papers by same author –some possibly closer to philosophy than physics, and i can’t really tell if they make sense– he has some things in ‘conference proceedings’ which also had papers by Louis Kauffmann (‘knots and physics’–which if i recall even discusses a bit of biology) and G t’Hooft’ (‘quantum cellular automata’, and ‘standard model’

T’Hooft was advised to go into physics by N G Van Kampen—a relative–famous in statistical mechanics , and one of few people i thought i could understand .)

.

Category theory came up recently in an ‘ecology’ list I’m on and it mentioned your page and its references—but the people on that list were mostly interested in applications to programming (eg Haskell–i’m not a programmer). .

Most pop science books i have seen recently seem to mostly rewrite things that have been written in pop books many times before. (Penrose is an exception.) (My favorite pop math book was by Tobias Dantzig –‘number: the language of science’ –my father got that in a used book store for 50 cents. His son is known for linear programming, and i see that as related to ‘potential theory’, calculus of variations, multiobjective optimization and even diffusion and ricci flow.)

(Last paper i read by L Smolin was on ‘gauge theory of economics’ (on arxiv) —it seemed to be either correct or on the right track (and seemed to rephrase the SMD theorem of economics in physics terms–S is Sonnenchein who became president of U Chicago; M is Mantel and D is Debreu. )

.

]]>**Evidence of a Decline in Electricity Use by U.S. Households**

Abstract

*This paper shows that U.S. households use less electricity than they did ﬁve years ago. The decrease has been experienced broadly, in virtually all U.S. states and across all seasons of the year. This pattern stands in sharp contrast to steady increases throughout previous decades and has signiﬁcant implications for household budgets, energy markets, and the environment. I discuss some of the implications of the decline and then take preliminary steps toward identifying potential explanations. While multiple factors have contributed, I argue that the rapid emergence of LEDs and other energy eﬃcient lighting has played a particularly important role.*

http://e2e.haas.berkeley.edu/pdf/workingpapers/WP030.pdf?mod=article_inline

Via the Wall Street Journal

**Americans Are No Longer Gluttons for Electricity—Thank the LED Bulb**

After increasing 10-fold between 1950 and 2010, average residential consumption dipped

*“Is this a small pause?” he asked. “Or will we all buy electric vehicles?”*

*That would reduce vehicle emissions by half. But, Dr. Davis said, it would accelerate household electricity use by 20% overnight.*

Penrose’s *Road to Reality* would have been absolutely wonderful to read when I was student. It would have saved me years of work, because he explains a lot of mathematics and physics in a detailed yet friendly way. As you suggest, it’s not popularization so much as clear explanation.

I wonder if you have come across the ‘Vaxjo interpretation of quantum mechanics’ from Sweden.

Smolin had some interesting popular books—i can’t say i understand this—along with Julian Barbour, C Rovelli, etc. (I’m more interested in Ricci flow and its connection to classical diffusion problems– or even the ‘classic paper’ by Marc Kac ‘can you hear the shape of a drum?”.

I also ‘wonder why i wonder why i wonder.. ‘ about any of this. i guess it passes the time.

]]>**The Return of Nature**

How Technology Liberates the Environment

https://thebreakthrough.org/journal/issue-5/the-return-of-nature

*Agriculture has always been the greatest destroyer of nature, stripping and despoiling it, and reducing acreage left. Then, in about 1940, acreage and yield decoupled in the United States. Since then American farmers have quintupled corn while using the same or even less land.*

[ … ]

*Crucially, rising yields have not required more tons of fertilizer or other inputs. The inputs to agriculture have plateaued and then fallen — not just cropland but nitrogen, phosphates, potash, and even water. A recent meta-analysis by Wilhelm Klümper and Matin Qaim of 147 original studies of recent trends in high-yield farming for soy, maize, and cotton, funded by the German government and the European Union, found a 37 percent decline in chemical pesticide use while crop yields rose 22 percent. This is the story of precision agriculture, in which we use more bits, not more kilowatts or gallons. *

[ … ]

*In addition to peak farmland and peak timber, America may also be experiencing peak use of many other resources. Back in the 1970s, it was thought that America’s growing appetite might exhaust Earth’s crust of just about every metal and mineral. But a surprising thing happened: even as our population kept growing, the intensity of use of the resources began to fall. For each new dollar in the economy, we used less copper and steel than we had used before — not just the relative but also the absolute use of nine basic commodities, flat or falling for about 20 years. By about 1990, Americans even began to use less plastic. America has started to dematerialize. *

[ … ]

*But even Californians economizing on water in the midst of a drought may be surprised at what has happened to water withdrawals in America since 1970. Expert projections made in the 1970s showed rising water use to the year 2000, but what actually happened was a leveling off. While America added 80 million people –– the population of Turkey –– American water use stayed flat. In fact, US Geological Survey data through 2010 shows that water use has now declined below the level of 1970, while production of corn, for example, has tripled (Figure 11). More efficient water use in farming and power generation contribute the most to the reduction.*

Interesting stuff. Much more at the link.

]]>Is there a reason we can’t do a similar “downset” construction directly on the monoidal category? (I think it would give a distributive monoidal category or something similar.) Quantales have a cool name, but in general it’s better to use categories than posets whenever possible.

I replied:

]]>Downsets are to posets as

presheavesare to categories!A poset is a Bool-enriched category and a downset is a Bool-functor just as a presheaf on a category is a functor

To see this, notice that given a poset a Bool-functor is a map from to truth values such that if true and q ≤ p then true. So, the subset of where equals true is a downset… and conversely, any downset gives a Bool-functor

So, when we form the poset of all downsets in , it’s the Bool-enriched version of forming the category of all presheaves on a category . Both are examples of a general ‘cocompletion’ process.

The category of presheaves on a category is the free cocomplete category on . The poset of downsets of (ordered by inclusion) is the free cocomplete poset on

A cocomplete poset is one that has all colimits. But this just says every subset has a least upper bound, also known as its

join. A cocomplete poset is also called asuplattice.There’s a category SupLat of suplattices, where morphisms are order-preserving maps that preserve least upper bounds (= colimits = joins):

Taking the poset of all downsets is the left adjoint of the forgetful functor SupLat Poset.

There’s a tensor product of suplattices, and a quantale is just a monoid object in (SupLat, ⊗).

There’s a tensor product of cocomplete categories, and a pseudomonoid in (complete categories, ⊗) is what I call a

2-rig. A 2-rig is a monoidal category with colimits, where tensoring with any object (on either the left or right) preserves colimits.So yeah, we don’t have to descend to the world of posets. Any Petri net gives a commutative monoidal category, and the category of presheaves on that is a commutative 2-rig!

If I hadn’t made that edit, you probably wouldn’t have caught that typo! Thanks—I’ll fix it now!

]]>possible typo: “then x is also in the set” -> “then y is also in the set”

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