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NNadir

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Chemical Principles of Topological Semimetals

In the midst of the White House generated horror of the last days, I had the guilty pleasure of attending my favorite kind of lecture: A lecture that was not only on a subject about which I know nothing, but on a subject about which I never even heard, topological semimetals.

One of my goals in life is to feel as often as is possible like I'm the dumbest person in the room, and I definitely succeeded in this case.

The lecture was given by Dr. Leslie M. Schoop, the newest faculty member of the Princeton University Department of Chemistry.



I immediately went home after the lecture and began to look into the topic and was pleased to see that I recently downloaded (but clearly didn't read) a review article written by Dr. Schoop and her colleagues.

The article, from which the total of this post is taken is here: Chemical Principles of Topological Semimetals (Leslie M. Schoop,*,† Florian Pielnhofer,‡ and Bettina V. Lotsch, Chem. Mater., 2018, 30 (10), pp 3155–3176)

It's a relatively new, if rapidly expanding field, so I guess I can be excused for knowing nothing at all about it, but it apparently involves some novel particle physics apparently predicted by the mathematical physicist Hermann Weyl during the scientifically transcendent 20th century.

Since it involves the structure of matter, I plan to share this with my son when he returns from Europe, I believe he'll find it cool.

Much of the topic remains over my head, but I thought it might be interesting to post brief excerpts of the paper along with some of the beautiful graphics from it.

The practical application, should it ever develop, would be computers so fast as to revolutionize computation as much as the original digital computer did in the 20th century, the elusive quantum computer: At least this is what Dr. Shoop claimed.

The recent rapid development in the field of topological materials (see Figure 1) raises expectations that these materials might allow solving a large variety of current challenges in condensed matter science, ranging from applications in quantum computing, to infrared sensors or heterogeneous catalysis.(1−8) In addition, exciting predictions of completely new physical phenomena that could arise in topological materials drive the interest in these compounds.(9,10) For example, charge carriers might behave completely different from what we expect from the current laws of physics if they travel through topologically non-trivial systems.(11,12) This happens because charge carriers in topological materials can be different from the normal type of Fermions we know, which in turn affects the transport properties of the material. It has also been proposed that we could even find “new Fermions”, i.e., Fermions that are different from the types we currently know in condensed matter systems as well as in particle physics.(10) Such proposals connect the fields of high-energy or particle physics, whose goal it is to understand the universe and all the particles of which it is composed, with condensed matter physics, where the same type, or even additional types, of particles can be found as so-called quasi-particles, meaning that the charge carriers behave in a similar way as it would be expected from a certain particle existing in free space...




The caption:

Figure 1. Timeline of recent developments in the field of topologically non-trivial materials.


The intro continues:

...
he field of topology evolved from the idea that there can be insulators whose band structure is fundamentally different (i.e., has a different topology) from that of the common insulators we know. If two insulators with different topologies are brought into contact, electrons that have no mass and cannot be back scattered are supposed to appear at the interface. These edge states also appear if a topological insulator (TI) is in contact with air, a trivial insulator. 2D TIs have conducting edge states, whereas 3D TIs, which were discovered later, have conducting surface states. TIs have already been reviewed multiple times,(13−16) which is why we focus here on the newer kind of topological materials, namely topological semimetals (TSMs)...


The review then discusses the remarkable properties of graphene which Dr. Schoop remarked with some amusement can be made by peeling a single layer of carbon atoms off of graphite with masking tape.

...But let us first take a step back to look with a chemist’s eyes at graphene and try to understand why it is so special. As chemists we would think of graphene as an sp2-hybridized network of carbon atoms. Thus, three out of C’s four electrons are used to form the σ-bonds of the in-plane sp2-hybridized carbon backbone (Figure 2a). The remaining electron will occupy the pz-orbital, and since all C–C bonds in graphene have the same length, we know that these electrons are delocalized over the complete graphene sheet. Since graphene is an extended crystalline solid, the pz-orbitals are better described as a pz-band (Figure 2b). Since there is one electron per C available, this pz-band is exactly half-filled (Figure 2c).




The caption:

Figure 2. Intuitive approach for describing the electronic structure of graphene. (a) Real-space structure of graphene, highlighting the delocalized π-system. (b) Orbital structure and band filling in graphene. (c) Corresponding electronic structure in k-space; only one atom per unit cell is considered. (d) Unit cell of graphene, containing two atoms. (e) Brillouin zone of graphene. (f) Folded band structure of panel (c), in accordance with the doubling of the unit cell. (g) Hypothetical version of distorted bands with localized double bonds. This type of distorted honeycomb can be found in oxide materials such as Na3Cu2SbO6.(58)


Some remarks on graphene as a prototype of the "Dirac Semimetal"

Most TSMs have in common that their unusual band topology arises from a band inversion. Unlike TIs, they do not have a band gap in their electronic structure. There are several classes of TSMs: Dirac semimetals (DSMs), Weyl semimetals (WSMs), and nodal line semimetals (NLSMs). All these kinds exist as “conventional” types; i.e., they are based on a band inversion. In addition, they can also be protected by non-symmorphic symmetry. The latter ones have to be viewed differently, and we will discuss them after introducing the conventional ones.

Dirac Semimetals

The prototype of a DSM is graphene. The “perfect” DSM has the same electronic structure of graphene; i.e., it should consist of two sets of linearly dispersed bands that cross each other at a single point. Ideally, no other states should interfere at the Fermi level. Note that in a DSM, the bands that cross are spin degenerate, meaning that we would call them two-fold degenerate, and thus the Dirac point is four-fold degenerate. When discussing degeneracies within this Review, we will always refer to spin orbitals. In any crystal that is inversion symmetric and non-magnetic (i.e., time reversal symmetry is present), all bands will always be two-fold degenerate. Time reversal symmetry (T-symmetry) means that a system’s properties do not change if a clock runs backward. A requirement for T-symmetry is that electrons at momentum points k and −k have opposite spin, which means that the spin has to rotate with k around the Fermi surface since backscattering between k and −k is forbidden. Introducing a perturbation, e.g., an external magnetic field, lifts the spin degeneracy and violates T-symmetry.




The caption:

Figure 3. Explanation of band inversions. (a) Rough density of states (DOS) of transition metals. Band inversions are possible between the different orbitals within one shell, but the material is likely to be metallic. (b) Band inversion between an s-band and a p-band. (c) Molecular orbital diagram of water. (d) Bands that cross and have the same irreducible representation (irrep) gap. (e) If the irreducible representations are different, the crossing is protected, but SOC might still create a gap.


"SOC" is spin orbit coupling.

Weyl Semimetals:

Weyl Semimetals

The difference between a DSM and a WSM is that, in the latter, the crossing point is only two-fold degenerate.(28,93,94) This is because in WSMs the bands are spin split; thus each band is only singly degenerate. If a spin-up band and a spin-down band cross, this results in a Weyl monopole, meaning that there is a chirality assigned to this crossing. Since there cannot be a net chirality in the crystals, Weyl cones always come in pairs. The resulting Weyl Fermions are chiral in nature and thus will behave physically different from “regular” Fermions. One example of this manifestation is the chiral anomaly, which we will discuss in the Properties and Applications of TSMs section below. Here, we will focus on the requirements necessary to realize a WSM.
In order to have spin split bands, we cannot have inversion (I) and time-reversal (T) symmetry at the same time, since the combination of these two symmetries will always force all bands to be doubly degenerate. In I asymmetric, i.e., non-centrosymmetric crystals, this degeneracy can be lifted with the help of SOC; this is the so-called Dresselhaus effect.(95)




The caption:

Figure 4. Different ways to achieve a Weyl semimetal. (a) Effect of T- and I-symmetry breaking on a single band. (b) The same scenario for a Dirac crossing. In the case of T breaking, two Weyl crossings will appear on the high-symmetry line at different energies. In the case of I breaking, they will appear away from the high-symmetry line. (c) Schematic drawing of a type I (left) and a type II (right) WSM.


Figures for a 3D Dirac Semimetal, trisodium bismuthide, a Zintl salt (at least I knew about Zintl salts for the lecture):



The caption:

Figure 7. (a) Crystal structure of Na3Bi. (b) First Brillouin zone with high-symmetry points and highlighted Dirac points. (c) Bulk band structure. (d) 3D intensity plot of the ARPES spectra at the Dirac point. Panels b and d reprinted with permission from ref (143). Copyright 2014 The American Association for the Advancement of Science. Panel c reprinted with permission from ref (168). Copyright 2017 Springer Nature.


A Weyl Semimetal:



The caption:

Figure 8. (a) Crystal structure of TaAs. (b) Brillouin zone. (c) Band structure without and (d) with SOC. (e) Photoemission spectrum with overlaid calculated band structure. (f) Calculated and measured Fermi surface, displaying the Fermi arcs, which are the signature to identify WSMs. Panels b–d reprinted with permission from ref (149). Copyright 2015 Springer Nature. Panels e and f reprinted with permission from ref (91). Copyright 2015 Springer Nature.


A "Non-symmorphic Topological Semimetal: "



The caption:

Figure 9. (a) Crystal structure of ZrSiS. (b) Brillouin zone in space group 129, with highlighted degeneracy enforced by non-symmorphic symmetry. (c) Bulk band structure of ZrSiS. The two degeneracies enforced by non-symmorphic symmetry at the X point are highlighted in blue (above EF) and orange (below EF). (d) Effect of the c/a ratio of isostructural and isoelectronic analogues of ZrSiS on the non-symmorphically induced degeneracies at X. While most compounds exhibit these crossings below and above the Fermi level, there are two exceptions: HfSiTe and ZrSiTe. (e) ARPES spectrum of ZrSiS near X along Γ-X. Two bands cross at X due to the non-symmorphic symmetry. Above the crossing, a very intensive surface state(205) is visible. Panel b reprinted with permission from ref (207). Copyright 2017 Elsevier. Panel c adapted and panel e reprinted with permission from ref (24). Copyright 2016 Springer Nature. Panel d reprinted with permission from ref (132). Copyright 2016 IOP Publishing.


And now, to generate some interest in saving the world after Elon Musk is done saving the world, a possible application, the ever popular solar hydrogen:



Figure 11. Schematic diagram of a topological Weyl semimetal for catalyzing the dye-sensitized hydrogen evolution. Reprinted with permission from ref (7). Copyright 2017 John Wiley and Sons.


Well, at least the degeneracy here doesn't involve that awful excuse for a human being in the White House.

A little interesting if still obscure, at least to me, science is a great way to escape. It's a pleasure to be the dumbest guy in the room, really a pleasure.

I wish you a pleasant day tomorrow.

The greatest car ever, the car that saved all life on earth, spontaneously ignites.

Tesla spontaneously catches fire with no crash



It's green. It's solar. It's wind turbiney. It's the savior of the common man. We need this car more than life itself. The entire US budget should be devoted to its worship.

People Get Ready.

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2017 Establishes a New Record for Coal and For So Called "Renewables."

The data comes from the BP Statistical Report, which is generally more current than the WEO (published each November) but perhaps not as accurate.

I've downloaded all the data from the BP Report nonetheless, and am going through it. It's an interesting read, showing that things are every bit as bad as I've come to believe, maybe even worse, particularly since energy and environmental issues are filled with so much wishful thinking, outright delusion, and denial on both ends of the political spectrum, this in a world where the center is disappearing.

Other big "winners," besides so called "renewables" and coal were oil and gas, and oh, yes, carbon dioxide emissions.

Carbon Brief: BP Global Data Shows Record Highs for Coal Power

There's a certain amount of "percent talk" here about so called "renewable energy," which is tightly linked to the use of dangerous fossil fuels.

The so called "renewable energy" industry remains what it has always been, trivial, outside of "percent talk" compared to dangerous fossil fuels, and is clearly incompetent to stop their growth.

Oh my God! I was there last evening. This is terrible at a beautiful community event.

My son had a painting on display there.

This is horrible, particularly because "Mothers against gun" had a display there.

Screw the NRA.

Kinetic Modeling of the Sulfur Iodine Process for Thermochemical Water Splitting to Produce Hydrogen

The paper from the primary scientific literature in this post is this one: Building and Verifying a Model for Mass Transfer and Reaction Kinetics of the Bunsen Reaction in the Iodine–Sulfur Process (Zhang et al Ind. Eng. Chem. Res., 2018, 57 (23), pp 7771–7782).

The "Sulfur Iodine Process" sometimes called the "Sulfur Iodine Cycle" or "SI cycle" or (herein) the "IS process" is a process for splitting water using heat, and thus is vastly thermodynamically more efficient than electrolysis and almost infinitely cleaner, depending on the source of heat, the primary energy, than the process by which 99% of the hydrogen on this planet is produced today, the steam reforming of dangerous natural gas or dangerous coal.

There are many thermochemical water splitting processes by the way, and over the years I've familiarized myself with many of them.

The paper is product of scientists at Institute of Nuclear and New Energy Technology, Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Beijing, 100084, China. For those who don't know, in international rankings, Tsinghua is known to be one of the greatest universities on this planet, and is sometimes ranked in international rankings higher than MIT, depending on the ranking criteria. The people who do research there are smarter than I am, and, I'm sure in many cases among readers, smarter than you are.

Nevertheless, I still feel free to disagree with the last sentence in their opening paragraph:

Hydrogen has received increasing attention in recent years as a potential fuel for fuel cell vehicles (FCV), and the demand for hydrogen will dramatically increase with the maturity of the FCV technology.1 However, most of the currently used hydrogen is produced from fossil fuels by reforming accompanied by emission of large amounts of CO2, which is assumed to be responsible for global warming. Hydrogen can be produced in an efficient, CO2 free, and large-scale manner through a thermochemical water-splitting process using nuclear energy, specifically, using the process heat of a high temperature gas-cooled nuclear reactor (HTGR).2,3 The iodine−sulfur (IS) process is considered the most promising thermochemical technique for nuclear hydrogen production.4


I personally believe other thermochemical cycles may be more promising, including some involving boiling metals or nanoceramics in flow cells, but that's just my opinion, and again, I'm not that smart.

In any case a 10MW high temperature gas cooled nuclear reactor has operated at Tsinghua University since the year 2000. It's a "pebble bed" type reactor modeled on German technology developed before Germany went "Energy Stupid." It's not my favorite kind of nuclear reactor, but it works.

The Chinese are smarter than we are because they built the reactor in the first place, and it was a new reactor in this century.

I had heard that Chinese scientists were going to fit this reactor to demonstrate the "SI cycle," but haven't kept up with progress in that area, but apparently the process is still getting significant consideration there, as demonstrated in this very recent paper.

The authors describe the "IS process" thusly:



The IS process consists of the following three chemical reactions: (5)

Bunsen reaction: I2 + SO2 + 2H2O = H2SO4 + 2HI

HI decomposition: 2HI = H2 + I2

Sulfuric acid decomposition: H2SO4 = SO2 + 1/2O2 + H2O

The net reaction of the above-mentioned chemical reactions is water decomposition (H2O = H2 + 1/2O2).


Actually in many accounts, what is called the Bunsen reaction above can be actually divided into two separate reactions with the intermediate being sulfuryl iodide, SO2I2, not to be confused with thionyl iodide, a sulfur species in a lower oxidation state. In theory and perhaps in practice, this intermediate could be isolated. I believe that like its chlorine analog, it's a distillable liquid.

An putative advantage of the SI cycle is that most of the materials in it are either liquids or gases, with the possible exception of iodine, although if you have ever worked with free iodine, you have noted that it appreciably sublimes, a gas phase is always above the solid phase, a situation that is also observed with liquid elemental bromine. (There are many variants of bromine based thermochemical cycles by the way.)

The authors discuss these properties, the phase related systems in their text considering how these phase relations affect kinetics that is, the speed at which the process can operate, which is the focus of their beautiful paper. They write, describing the focus of their work:

In the IS process, H2SO4 and HI are produced by the Bunsen reaction among SO2, I2, and H2O, thereby inducing the decomposition reactions of H2SO4 and HI acids. The decomposition products of HI and H2SO4 (i.e., SO2, I2, and H2O) are recycled for the Bunsen reaction. At the initial stage of the IS process, the Bunsen reaction is a three-phase heterogeneous reaction; that is, the gaseous SO2 reacts with solid I2 and liquid H2O. The Bunsen reaction becomes a gas− liquid slurry reaction, in which the recycled gases react with I2 in the HI solution when the IS process is continuously operated under cycling conditions. Most studies on the Bunsen reaction have focused on thermodynamics, including phase separation characteristics, side reactions, and optimization of operational parameters.11−14 The results guarantee that the Bunsen reaction favors thermodynamic conditions and spontaneous product separation. Kinetics data are crucial to reactor design and nonsteady-state operation. However, few studies involved the kinetics of the Bunsen reaction.


A graphic from the paper touches on some issues with phase behavior that they examine:



The caption:

Figure 1. Gas−liquid Bunsen reaction.


In phase interfaces in chemical processes surface area plays a huge role, and hence the discussion of thin films.

The authors construct models for various aspects involved in the kinetics of this system and produce some graphics involved in considerations of various reaction conditions comparing the model with experimental conditions obtained.

For example:



The caption:

Figure 3. Comparison between the model results using eq 42 and the experimental results: (a) 161 kPa, [I2] = 0.6521 mol/L, 40 °C; (b) 163 kPa, [I2] = 0.4933 mol/L, 40 °C.


...and...




The caption:

Figure 4. Comparison between model results based on the average parameter and experimental results


Then there are some Henry's law graphics about mass transfer:



The caption:

Figure 7. Comparison of the mass-transfer coefficients between the model and the experimental results under different initial SO2 pressures and I2 concentrations.Figure 7. Comparison of the mass-transfer coefficients between the model and the experimental results under different initial SO2 pressures and I2
concentrations.


More mass transfer:



The caption:


Figure 8. Comparison between the model and the experimental results under different initial pressures and I2 concentrations.
Figure


If you are a scientist you already know this, but if you aren't, and find this topic interesting, this might be helpful.

Anything that is flammable is thermodynamically unstable. Wood, for example, in an oxygen atmosphere would rather be carbon dioxide and water, but is stuck being wood because of kinetics, and kinetics in turn is determined by activation energy required to start it. When you burn wood, you provide this activation by using a match, and the match in turn, is ignited by the energy input from friction when you strike it. Because some thermodynamically favorable reactions require energy inputs to get them started, they are able to persist for long periods of time, we say they are "metastable." You by the way, are metastable. So are diamonds at ordinary temperatures and pressures; diamonds are not forever.

One of the first Nobel Laureates, Svante Arrhenius, found a way to determine the activation energy to make thermodynamically favorable reactions like the combustion of wood happen. It is called the Arrhenius equation, after its discoverer and it remains more than a century after its discovery one of the most important equations there is. It is exponential in format, but is often treated as its natural logarithm which makes it essentially linear:



The authors construct Arrhenius plots for the Bunsen reaction:



The caption:

Figure 11. Arrhenius plot for eq 42.


And they find the rate equation for the reaction:



The authors conclude:

An integral multiphase Bunsen reaction model is built on the basis of double-film theory and experimental results. A Bunsen reaction mechanism is proposed, and different reaction rate equation models are deduced on the basis of different rate determining steps. The parameters in the reaction and mass transfer models were regressed, and the models were verified on the basis of the experimental results and differential equation parameter regression approaches. The empirical relation equation of the mass-transfer coefficient of liquid phase with SO2 pressure and iodine concentration is established. All model results agree well with the experimental results, thereby indicating an error of lower than 1%. This result reflects that the established model can simulate and predict the experimental process accurately. The proposed reaction mechanism and deduced reaction rate equations are reliable.


Whether you believe it or not - despite whatever horseshit you've heard - the conversion of nuclear energy into chemical energy without the intermediate use of electricity is one of the key technologies for the creation of a sustainable and just world, which is, regrettably, not even close to the world in which we live.

These Chinese scientists irrespective of who pays them or the government under which they live are working in service of humanity, even as the world lives increasingly under a dictatorship of self serving mindless fools.

I am thankful this work is being done.

I am having the best Father's day in my life as a father, since both my sons are doing very well at the things they love, which is all for which a father can hope. If you are a father, I wish you the same.








Large-Scale Uranium Contamination of Groundwater Resources in India.

The paper to which I will refer has the same title as this post, and is published in the current issue of rapid communications environmental journal published by the American Chemical Society. It is this one: Large-Scale Uranium Contamination of Groundwater Resources in India (Vengosh et al Environ. Sci. Technol. Lett., 2018, 5 (6), pp 341–347.

Some text from the introduction to the paper:

India, the world’s second most populous country, extracts more than a third of worldwide groundwater resources, more than 90% of which is used for irrigation.1 Intense abstraction has led to severe groundwater table declines in many parts of the country, especially in the northwestern Indian states of Punjab, Haryana, and Rajasthan.2−5 In 2013, the Indian Central Groundwater Board estimated that groundwater in the majority (66−70%) of blocks (Indian administrative division above village) in these three states was either critically exploited or overexploited.5 At the same time, parts of northwestern India that import surface water through canals are dealing with water logging issues, even in arid, previously groundwater-deficient areas.2,4−6 Overexploitation of groundwater and the use of imported surface water, combined with reported changes in precipitation patterns induced by climate change, have raised concerns about future water sustainability in India,2−4 yet water quality issues are perhaps even more pressing. High concentrations of salinity, fluoride, and nitrate are widespread in groundwater resources throughout the country.6−8 Groundwater arsenic problems have been reported in the delta aquifers of West Bengal and Bangladesh, as well as along the Indo- Gangetic Basin aquifer in Pakistan.2,9 There are also reports of high levels of uranium in groundwater, particularly in northwestern India, which is the focus of this study.

Uranium’s threat to human health comes from its chemical rather than it's radiological properties. Epidemiological and toxicological studies have examined the link between the prevalence of uranium in water and chronic kidney disease (CKD) and demonstrated that exposure to uranium through drinking water is associated with nephrotoxic effects.10-12


The authors produce a map as a graphic to show where the problem is worst:



The caption:

Figure 1. (A) Distribution of major geological formations in India that compose local aquifers, combined with identified districts in India where uranium in groundwater has been reported to exceed (red zone) or not to exceed (blue zone) the World Health Organization provisional drinking water guideline value of 30 μg/L. (B) Distribution of uranium concentrations in groundwater collected in this study, together with the major geological formations and identified districts in Rajasthan and Gujarat, where uranium content in groundwater has been reported to exceed (red zone) or not to exceed (blue zone) 30 μg/L.


30 μg/L is the cutoff in the World Health Organization's provisional guideline for uranium concentrations in drinking water which is or was the equivalent standard at the EPA, at least before it was taken over a corrupt politician who hates science, scientists and the environment and is treating that organization as a personal bank for corrupt politicians who hate science, scientists and the environment.

Note that the authors attach this situation to geological formations, and that this situation is not involved with uranium mining but with the apparent occurrence of uranium ores through which the drinking water percolates.

This does not, however, imply that human activities have no connection to this situation, which the authors note.

The ocean contains about 5 billion tons of uranium, albeit in considerably lower concentrations than is found in the water supplies studied here. If we take the density of seawater to be 1030 kg/m^3, the figures given in this paper, which I pulled up more or less at random from such papers in my files Chemical Geology Volume 190, Issues 1–4, 30 October 2002, Pages 45-67, we can calculate that the concentration of uranium in seawater is about an order of magnitude lower, 3.4 μg/L. Many scientific publications give a figure close to this, with minor fluctuations owing to fluctuations in the density of seawater, which is not constant in all places.

Despite all of the talk from people who hate nuclear energy because they know nothing at all about the subject, who have appealed to "peak uranium" to claim that nuclear energy is not sustainable, uranium is not exhaustible, and no human technology can ever consume it.

It is easy to show that if world per capita average power consumption doubled to around 5000W, (which is still half of the average power consumption of an "average" American), that a person living for 100 years would consume about 100 grams of uranium (converted to plutonium) in their entire lifetime. An appreciation of how much uranium has already been mined shows that the quantity is sufficient to supply 100% of humanity's energy consumption for several centuries, even without the greater quantities of thorium that have been mined and dumped as a side product of the lanthanide industry that supports our stupid, environmentally unacceptable and useless wind industry, among other industries.

The recovery of oceanic uranium for use in nuclear reactors has been under study for more than half a century and the technology is well understood. Because uranium is so cheap from terrestrial ores (and would be even cheaper were we to do away with the stupid practice of dumping so called "depleted uranium" ) the cost of recovering uranium from seawater is not justified as of yet, but since in terms of cost per unit of energy provided, the cost of uranium is trivial with respect to the cost of nuclear energy. Like the cost of the useless and failed solar energy industry, the cost of fuel doesn't matter all that much; it's the device that counts.

If at some point stupid people stop ruling the world, and thus the world energy supply goes nuclear, several hundred years from now, people might be inclined to obtain their uranium from seawater, which is possible because of the extremely high energy density of uranium. (Since it is this factor, the energy to mass ratio, is the most important in determining the environmental impact of a form of energy and its economic viability and sustainability, it follows that nuclear fission is the cleanest form of energy possible, unless of course, as had yet to happen, a viable fusion energy device is made to work.) But one might argue that doing this, obtaining uranium from seawater, one could drain the seas of its uranium.

This however is not possible, because the uranium in seawater is actually a tiny fraction of the uranium on the planet as a whole and in fact represents a small part of a natural uranium cycle.

This brings me back to India.

Most people who have studied nuclear issues and nuclear policy - this excludes 99% of nuclear energy opponents, the overwhelming majority of whom argue from ignorance - will understand that the Indian nuclear energy program is geared to utilizing India's large thorium reserves, primarily because India has very few reserves of terrestrial ores of uranium that can be recovered at current low prices. For this reason the majority of nuclear reactors in India are heavy water reactors, which are suitable for breeding U-233 from thorium. However the solubility of thorium is rather low in most aqueous systems (although this is not the case for its radioactive decay daughters). This means that if one considers eternity a thorium/uranium cycle is not sustainable but a uranium/plutonium cycle is.

Since uranium is not present in Indian ores, they have actually built a pilot plant to extract uranium from seawater. Here's a picture of it:



(Source: Linfeng Rao, LBNL Paper LBNL-4034E (2010))

In a blog post elsewhere, I examined the uranium cycle in some detail and using one of the references I supplied therein, among many others, U-Th-Ra Fractionation During Weathering and River Transport (Chabuax et al, Reviews in Mineralogy and Geochemistry (2003) 52 (1): 533-576) A nice table in the paper gives the quantities of uranium transported by rivers to the sea from the weathering of rocks. Three of the top five are major rivers in India: They are the Indus, the Ganges, and the Brahmaputra rivers, with the other two in the top five being the Mississippi and the Yangtze.

Sustaining the Wind, Part 3, Is Uranium Exhaustible?

Now let's return to the paper cited in the beginning of this post.

The authors note that the mobilization of uranium into the ground water is only possible if two conditions are met. One is the presence of carbonate, because in the ocean and in any other aqueous system this solubility is tied to the carbonate complex. The other is the presence of an oxidizing agent, since the carbonate complex of uranium (VI) is soluble, and the same complex of uranium (IV), the other common oxidation state in terrestrial uranium ores is not.

They write:

Controls on the Occurrence of Uranium. Bicarbonate complexation and oxidizing conditions are two of the most important chemical factors controlling uranium concentrations in groundwater20,25,26,32−34 and appear to be the key factors for the alluvial aquifers in northwestern India. The accumulation of bicarbonate in groundwater enhances the formation of highly soluble uranyl carbonate complexes, which results in elevated uranium concentrations in groundwater. This process is evidenced by the correlation between bicarbonate and uranium in groundwater from most of the aquifers in Rajasthan and Gujarat (Figure 2B and Table S6). This is consistent with speciation modeling conducted with PHREEQC, which predicted that uranyl carbonate species, especially ternary complexes with Ca, are the predominant uranium complexes in groundwater from the alluvium aquifers (Table S7).

Additionally, previous studies have observed massive groundwater table declines in many areas in the unconfined alluvial aquifers of northwestern India.5 This hydrogeological condition likely promotes oxic conditions, which favor the occurrence of uranium as a soluble complex and migration into deeper parts of the aquifer. Although neither oxidation−reduction potential nor dissolved oxygen concentration was directly measured, relatively low concentrations of both iron and manganese and high nitrate concentrations further support our hypothesis of oxidizing conditions in the shallow U-rich groundwater (Table S2).


They note that the conditions under which the uranium is mobilized are obtained by the percolation of water through agricultural fields, particularly because of the accumulation of nitrate, as well as the effect of cycling water through the air, which is increasingly concentrated with the dangerous fossil fuel waste carbon dioxide while we all wait, like Godot, for the grand so called "renewable energy" fantasy to become reality.

They have a nice graphic discussing carbonate and uranium fluxes in drinking and agricultural water:



The caption:

Figure 2. (A) Box plots of uranium concentrations of groundwater from different aquifers in Rajasthan and Gujarat investigated in this study. Red lines represent the WHO’s provisional guideline values for uranium in drinking water. For statistical analysis of the differences in U distribution by aquifer, see Table S4. (B) Uranium vs bicarbonate concentrations in groundwater sorted by aquifer lithology. See Table S6 for Spearman correlations sorted by aquifer.


That the source of the uranium derives from naturally occurring rocks and not from human industrial nuclear practice is indicated by the U234/U238 ratio since U234, always in equilibrium with U238 is mobilized by the recoil of alpha decay. A graphic on that point:



The caption:

Figure 3. 234U/238U activity ratios vs uranium concentration in groundwater from the alluvial aquifers in Rajasthan and Gujarat. The blue line represents secular equilibrium in which the 234U/238U activity ratio is ∼1. 234U/238U activity ratios of >1 observed in most of the investigated groundwater indicate selective 234U chemical mobilization and/or physical recoil from the aquifer rocks.


I believe that the value of "1" here refers to the normal secular equilibrium conditions, and not the actual ratio between U234 and U238.



I have written here that the extraction of uranium from seawater is not economically justifiable, and I certainly consider that the nuclear enterprise in a rational world as opposed to the one in we actually live would be powered essentially by so called "depleted uranium" with a little thorium thrown in to keep up supplies of neptunium to void nuclear weapons proliferation issues.

But the question is whether there is a moral and health reason to do it beyond the cost of ores.

Suppose the Indian government decided to purify the groundwater to remove the uranium it extracts from geological formations. Perhaps some of the cost might well be defrayed by selling or utilizing the uranium so recovered. There is no good reason that any of the many systems known to extract uranium from dilute solutions could not be used to remove uranium from drinking and agricultural water instead of seawater. And indeed, the higher concentrations in this water when compared to seawater would make the economics less onerous.

It's worth a shot.

Later, maybe this weekend, I hope to write a post, in response to an excellent question in one of my earlier posts here, to cover the "external costs" of dangerous natural gas, which will show despite common parlance, including much of it by idiotic anti-nukes who claim as evidence of their stupidity that "nuclear energy is not competitive," that natural gas is not cheap since it incurs a health and environmental cost that will fall mostly on future generations, who will have derived none of the benefits of the "cheap" natural gas now being burned in a sybaritic fashion by people with no concern whatsoever about the future.

The authors of the paper from which this post takes its title specifically mention climate change as a factor in the situation with respect to uranium in Indian drinking water. Of course, I assume that every time the words "uranium contamination" appear, the usual anti-nukes perk up their selectively attentive ears to find another insipid "argument" to criticize the nuclear industry. But to whom does the "external cost" of the uranium in Indian water actually accrue? Could it be that some of the moral responsibility lies with those who either deny climate change or propose silly failed schemes to address it?

I pose this question as I finish up by wishing you a very pleasant weekend, a pleasant "Father's Day," if you are involved in some way with a father.






Bats in the Anthropocene.

Many years ago, when my two sons were small, our neighbor used to invite us over to his house on summer evenings for drinks and conversation. Our kids kind of grew up to be different kinds of men, and we got busy and we sort of fell out of touch not because we didn't like each other - we still greet each other very warmly when we do see each other, but because...well, you know, "responsibilities..."

One such summer, a colony of bats moved into the rafters of his house, and at the crepuscule, the bats would come out, swarming and eating mosquitoes. Of course I couldn't tell much about the bats, they were shadows against the colored dying light on the horizon, but I remember how beautiful they were, God they were beautiful.

Some time back, in this space, I referred to a book I had just added to my collection called "Why Birds Matter," which was a book which I claimed justified the existence of birds on economic grounds.

We are so pathetic...

A Minor Problem For Sound Science of the Effect of Offshore Windfarms on Seabirds: There Isn't Any.

The wind industry is a trivial industry that is material intensive, unreliable, ineffective, expensive and dependent on the continuous manufacture of transient junk that last just a short time before becoming landfill, the ultimate consumerist bourgeois exercise in planned obsolescence that is designed to "make jobs" that are not only unproductive, but are actually destructive.

Despite half a century of cheering, and the expenditure of trillion dollar quantities of resources, climate change is worse than ever and we are using more dangerous fossil fuels than we have ever used.

Despite the obvious failure of this awful experiment there are still people who believe that every bit of open space should be turned into industrial parks for producing electricity in a way requiring redundancy and, as I will point out by reference to my latest edition to my collection of books on wildlife, destructive to an important element of the worldwide ecosystem, the creatures I evoked at the beginning, bats.

Before pointing to the book, let me point to a relatively recent paper from the primary scientific literature that states the problem quite clearly and well:

Behavior of bats at wind turbines (Cryan et al PNAS October 21, 2014. 111 (42) 15126-15131). This paper seems to be open sourced, but I'll excerpt it anyway:

Bats are dying in unprecedented numbers at wind turbines, but causes of their susceptibility are unknown. Fatalities peak during low-wind conditions in late summer and autumn and primarily involve species that evolved to roost in trees. Common behaviors of “tree bats” might put them at risk, yet the difficulty of observing high-flying nocturnal animals has limited our understanding of their behaviors around tall structures. We used thermal surveillance cameras for, to our knowledge, the first time to observe behaviors of bats at experimentally manipulated wind turbines over several months. We discovered previously undescribed patterns in the ways bats approach and interact with turbines, suggesting behaviors that evolved at tall trees might be the reason why many bats die at wind turbines...

...Bats are long-lived mammals with low reproductive potential and require high adult survivorship to maintain populations (1, 2). The recent phenomenon of widespread fatalities of bats at utility scale wind turbines represents a new hazard with the potential to detrimentally affect entire populations (3, 4). Bat fatalities have been found at wind turbines on several continents (3⇓⇓–6), with hypothesized estimates of fatalities in some regions ranging into the tens to hundreds of thousands of bats per year (4, 6). Before recent observations of dead bats beneath wind turbines, fatal collisions of bats with tall structures had been rarely recorded (7). Most fatalities reported from turbines in the United States, Canada, and Europe are of species that evolved to roost primarily in trees during much of the year (“tree bats”), some of which migrate long distances in spring and late summer to autumn (8). In North America, tree bats compose more than three-quarters of the reported bat fatalities found at wind-energy sites (6, 9), although there is a paucity of information from the southwestern United States and Mexico. Similar patterns occur in Europe (4). Another prominent pattern in bat fatality data from northern temperate zones is that most fatalities are found during late summer and autumn, sometimes with a much smaller peak of fatality in spring (4, 6). Concurrent involvement of species with shared behaviors suggests that behavior plays a key role in the susceptibility of bats to wind turbines, and that tree bats might somehow be attracted to wind turbines (8).


Don't worry, be happy. Wind turbines are "green" even if they have done absolutely nothing at all, zilch, zip, zero to arrest climate change, which is now taking place, after half a century of cheering for wind, at the fastest rate ever observed.

It's not results that count; it's "good" intentions.

The book I just downloaded is this one: Bats in the Anthropocene: Conservation of Bats in a Changing World

Apparently you can download this book for free. God bless Springer publishing, I love them.

An excerpt:

...This brings up an important question: Do nocturnal animals benefit less from legal protection than diurnal animals? Are we more concerned about animals that we see and interact with during daytime? Do human societies perceive and evaluate, for example, fatalities of birds of prey at wind turbines in a different way than bat fatalities when both ought to benefit from the same level of protection? Do we consider recommendations to reduce light pollution for the sake of nocturnal animals such as bats, or does the expansion of the human temporal niche into the night come at high costs for all nocturnal animals? In summary, we speculate that bats as nocturnal animals might be particularly exposed to human-induced ecological perturbations because we are driven by our visual system and therefore tend to neglect the dark side of conservation, i.e., the protection of nocturnal animals.


The authors then ask the question, "Why should we care about bats."

There's some nice and gracious lip service to the beauty of bats before we hear about the only thing we care about, money.


Recent attempts to critically review the ecosystem services provided by bats have revealed that many species offer unique and large-scale monetary benefits to agricultural industry (Kunz et al. 2011; Ghanem and Voigt 2012; Maas et al. 2015). For example, flowers of the Durian tree are only effectively pollinated by the Dawn bat, Eonycteris spelaea, in Southeast Asia (Bumrungsri et al. 2009). Durian is a highly valued fruit in Asia with Thailand producing a market value of durians of almost 600 million US$ annually (Ghanem and Voigt 2012). Other bats consume large amounts of pest insects, thereby offering services that could save millions of US$ for national industries (Boyles et al. 2011; Wanger et al. 2014). However, the monetary approach for protecting bat species is a double edged sword, since bat species without apparent use for human economy may not benefit from protection compared to those that provide some ecosystem services.


We are so pathetic...

Chapter 11 of this book is all about the high number of bat deaths at wind turbines, which is entirely OK because we need to grow the wind industry by zillions of percent because, who gives a shit about bats when we can all be "green" and drive swell electric cars made by the ever popular Elon Musk?

In this book, wind power is discussed as one of "the fastest growing sources of energy" even though it, um, isn't, and grew at 1/10th the rate of coal in the 21st century.

IEA 2017 World Energy Outlook, Table 2.2 page 79

But even if its useless, it's pretty good at killing bats.

However returning to accurate statements about their area of expertise, bats, even if they apparently don't know very much about energy they write:

Wind energy development is not environmentally neutral, and impacts to wildlife and their habitats have been documented and are of increasing concern. Wind energy development affects wildlife through direct mortality and indirectly through impacts on habitat structure and function (Arnett et al. 2007; Arnett 2012; NRC 2007; Strickland et al. 2011). Bats are killed by blunt force trauma or barotrauma and may also suffer from inner ear damage and other injuries not readily noticed by examining carcasses in the field (Baerwald et al. 2008; Grodsky et al. 2011; Rollins et al. 2012; Fig. 11.2). Kunz et al (2007a) proposed several hypotheses that may explain why bats are killed and some of these ideas have subsequently been discussed by others (e.g., Cryan and Barclay 2009; Rydell et al 2010a). Collisions at turbines do not appear to be chance events, and bats probably are attracted to turbines either directly, as turbines may resemble roosts (Cryan 2008), or indirectly, because turbines attract insects on which the bats feed (Rydell et al. 2010b). Horn et al. (2008) and Cryan et al. (2014) provide video evidence of possible attraction of bats to wind turbines.

Regardless of causal mechanisms, bat fatalities raise serious concerns about population-level impacts because bats are long-lived and have exceptionally low reproductive rates, and their population growth is relatively slow, which limits their ability to recover from declines and maintain sustainable populations (Barclay and Harder 2003). Additionally, other sources of mortality cumulatively threaten many populations. For example, white-nosed syndrome causes devastating declines in bat populations in the USA and Canada (e.g., Frick et al. 2010), and national programs for improving insulation of buildings, particularly in Northern Europe, cause losses of roosting opportunities for bats such as the common pipistrelle (Pipistrellus pipistrellus; Voigt et al. 2016). Thus, high wind turbine mortality poses a serious threat to bats unless solutions are developed and implemented...


There's plenty more where that comes from.

You know, when I was a kid, I was a member of the Sierra Club, which I then took - it may have been true then - to be an organization dedicated to saving the open spaces, habitat and ecosystems. And of course, I did that thing that clueless bourgeois types like me do, which was to dutifully drive to a shopping mall every Christmas season to get that de rigeur Sierra club calendar with all the rock formations, stream and forest pictures, all printed on recycled paper.

Eventually whether you like it or not, most boys grow up to be men.

That's not what the Sierra Club is today. Recently I attended the New Jersey "March for Science" which turned out to be, to my disgust, a "March for Renewable Energy" where I had to listen to the drivel of the asshole who heads that organization whose "environmental program" calls for destroying the offshore Benthic zone of New Jersey by turning it into an industrial park for wind turbines.

This so called "environmental" organization actually has photographs of a wind industrial park on its web page, at crepuscule no less, the perfect time to kill New Jersey bats.

To the modern New Jersey Sierra club, birds don't matter, nothing matters other than producing electricity some of the time using inefficient material intensive and most importantly useless.

The pathetic asshole who apparently hates bats is in the picture wearing a blue tie. He is, if you must know, one of the most ignorant people you can ever meet, that is if you, unlike him, actually know something about the environment.

Glenn Seaborg, winner of the Nobel Prize, adviser to every President from Harry Truman to Bill Clinton, former chancellor of the University of California, President of the American Chemical Society, discoverer of the final shape of the periodic table, discoverer of more than 10 elements in the periodic table, and Chairman of the Atomic Energy Commission during the most productive period of nuclear reactor building in world history, lead by the United States, was a member of the Sierra Club.

I can't speak for the great man, but I wouldn't be surprised if he would be as disgusted as I am by what that club has become.

I wish you a pleasant Tuesday.




All the World's Coal Plants, Mapped.

All the World's Coal Plants Mapped

This is an interactive map, and when it comes up, it will show 2017 on the slider bar.

You may have heard somewhere coal is dead. Maybe you believed it, or at least wanted to believe it.

Expand to Europe, push the slider bar to "Future" from 2017.

Take a look at China and India.

The US, a country of myopic provincials, is closing coal plants because in the US dangerous natural gas is believed to be "cheap." It isn't. It only appears so because the external costs of gas will fall on future generations who will conversely reap none, absolutely none of the benefits.

I wish you a pleasant work week.

Ameliorating the Fire Risk of Energy Storage Devices.

The paper I will discuss in this link from the primary scientific literature is this one:

Promising and Reversible Electrolyte with Thermal Switching Behavior for Safer Electrochemical Storage Devices (Xu et al, ACS Appl. Mater. Interfaces, 2018, 10 (8), pp 7171–7179)

As I frequently point out energy storage wastes energy, a consequence of the inviolable second law of thermodynamics, a law of physical science that all the wishful thinking in the world cannot repeal.

Nevertheless, like so called "renewable energy" itself, the idea of energy storage is inexplicably popular, perhaps because even the most enthusiastic and delusional partisans of so called "renewable energy" recognize, at least in the back of their minds if not consciously, that there are times when the wind does not blow at night. Since they are under the erroneous opinion that so called "renewable energy" is "green" and sustainable, they like to pretend that there is a simple solution in energy storage, and do all kinds of cheering for absurd stuff like Elon Musk's crappy car for billionaires and millionaires.

So called "renewable energy" has not worked; it is not working and it will not work to address climate change or reduce the use of dangerous fossil fuels.

On the other hand, energy storage devices are in fact commercial and work quite well, and are utilized on a grand scale in all sorts of devices, the overwhelming majority of them being portable devices even though, again, they waste energy. The idea of making portable devices however into utility scale devices, while already in some marginal practice to support the marginal and insignificant so called "renewable energy" devices is dubious, especially when one considers that large scale devices, since they waste energy, they can and sometimes do, exhibit heat exchange problems that can become uncontrolled and lead to fires and even explosions.

News item: Lithium-Ion Battery on Delta Air Lines Flight Explodes, Catches Fire

The ignition of batteries brought down UPS Flight 6 in Dubai, killing both pilots, one by asphyxiation, the other being killed when he couldn't land the plane because of smoke. It was covered in the wonderful if scary Smithsonian Channel Show Air Disasters.

News Item: Why the Fire that Incinerated a Tesla Was Such a Nightmare to Put Out

Reducing this risk is the topic of the paper cited at the beginning of this post.

Some commentary from the introduction to the paper:

Advanced electrochemical devices, such as supercapacitors, lithium-ion batteries, and nickel−metal hydride batteries, have been large-scale applied in energy storage because of their properties such as high power and energy densities,1,2 stable cycling performance, and long cycle life.3−8 Delivering energy at high rates, however, could cause security issues with respect to considerable amounts of gases and heat generated by ultrafast charging and discharging processes, especially in some extreme conditions such as short circuiting and overcharging, thus resulting in catastrophic burning or explosion.9,10 With the increasing oil crisis and continuous development of new energy vehicles, safety problems of large battery packs with high specific energy density are in urgent need of technical breakthroughs.

A series of exothermic reactions leading to a rapid rise in temperature and to thermal runaway can be initiated in addition to the charge/discharge cycle, including the thermal pyrolysis of electrodes and evolution of oxygen and hydrogen between the electrode/electrolyte interface, which in turn increases the internal cell temperature and pressure.11 Accordingly, effective suppression of thermal runaway is the premise of achieving safety application and plays a very important role in the research studies of high-energy storage devices.12


You hear people talking as if battery storage and so called "renewable energy" are already mainstream. They are not. They are trivial and if one believes these scientists - contempt for scientists and engineers is very popular on both political extremes - there are serious technical "breakthroughs" required.

The question that should arise in people's minds is therefore a question of time. It's 2018. We're at close to 412 ppm for the concentration of the dangerous fossil fuel waste carbon dioxide in the planetary atmosphere. We cannot continue - if, in spite of all evidence, we want to have any hope of elevating our ghastly impoverished moral standing - to bet the future on hopes for "breakthroughs." We're out of time to wait for them.

Nevertheless, the authors are doing what good scientists do, they are working to solve the problem that the existing problem represents. Their work involves "thermoresponsive polymers." The idea is to shut down the device before it gets too hot and catches fire or explodes. (It's better to have your swell Tesla car stall and be even more useless than it is to have it catch fire and kill people.)

They describe the current state of affairs:

Recently, researchers proposed to develop smart reversible electrolytes based on thermoresponsive polymers, which have unique lower-critical solution temperature (LCST), to cope with the issue of thermal runaway. The migrations of conductive ions in the reversible electrolytes exhibit temperature dependence due to the phase separation of LCST polymers, thus providing or inhibiting conductive paths to achieve the thermoreversible protection. To date most of the research studies have focused on poly(N-isopropylacrylamide)-based copolymers because of its extensive mature application in biomedicine.23,24 However, their actual applications in electrochemical energy storage are restricted by the low LCST at around 32−34 °C and complicated synthesis with low productivity. Although commercial thermoplastic elastomer Pluronic [poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide)] have been dissolved in the electrolyte to shutdown the electrochemical devices upon heating, the high concentration up to 30 wt % influences the electrochemical properties at room temperature and increases the cost.25


Then they discuss their approach:

Here, methyl cellulose (MC) is used as a stimuli-responsive material in the smart electrolyte because of its thermoreversible gelation property in aqueous solution at elevated temperatures. MC, a type of modified cellulose with a portion of hydroxyl groups substituted by hydrophobic groups, has been increasingly investigated as separators or binder materials instead of synthetic polymers for electrochemical devices owing to its characteristics such as abundance, regeneration, and low cost.26−31 In this study, MC molecules exist as randomly isolated chains in the electrolyte below the LCST when ions can move in the interspaces freely, enabling a high ionic conductivity, which is not possible with conventional flameretardant additives. When temperature increases, the electrolyte undergoes a thermally activated sol−gel transition, which results in a decreased ion concentration and broken circuit because the hydrophobic segment in MC molecular chains is tangled to inhibit the motion of ions. This process is reversible and returns to high conductivity after cooling, as shown in Figure 1. We chose MC as the stimuli-responsive material in reversible electrolytes based on the following considerations: (1) MC solution exhibits relatively proper transition temperatures, so that system can be shutdown before or at the early stage of thermal runaway; (2) it is sensitive to temperature change in abnormal conditions and low concentration (∼2 wt %), making it a cost-effective system; (3) it is inert and stable within the electrochemical environment, having little impact on the electrochemical performance.


Methyl cellulose can be obtained of course from wood and other biological materials and to the extent biological sources are used, this material might represent economically viable sequestration of atmospheric carbon, probably in amounts that would be trivial compared to our 35 billion ton dumping practices in use today, but perhaps meaningful in a world where carbon dumping was arrested by the expanded development and embrace of nuclear energy.

They then produce a graphic showing how their system is designed to work:



The caption:

Figure 1. (a) Schematic illustration of the smart electrolyte with reversible thermoresponsive gelation properties for electrochemical energy storage devices. The system works normally at room temperature because of the free migration of ions in the interspaces. On heating, the hydrophobic crosslinked network leads to the sol−gel transition and absence of moving ions from solution, thus effectively shutting down the device above the LCST. Upon cooling, the electrolyte reversibly transforms to solution and recovers its ion motion. (b) Structures of MC, showing hydrophilic and hydrophobic groups. (c) Digital photograph of a MC solution below and above the LCST. (d) FTIR of pure MC and the mixture solution of MC and 1 M H2SO4-based electrolyte before and after 10 CV cycles, respectively.


Here are the cyclic voltammetry (CV) curves showing the reversibility of charge and discharge, a property essential to make a viable battery:



The caption:


Figure 2. Electrochemical properties of AC electrodes in 2 wt % MC-based electrolyte (1 M H2SO4). The CV curves were performed at scan rates of 10, 50, and 100 mV/s on AC electrodes at (a) 25 and (b) 70 °C. The charge/discharge characteristics in reversible electrolyte using a current density of 3 A g−1 at (c) RT, 25 °C and (d) HT, 70 °C.


They test the shutdown of current in terms of heat responsiveness:



The caption:

Figure 4. (a)Temperature-dependent CV tests of the system based on electrolyte with 1 wt % MC solution. (b) Storage modulus G′ (black) and loss modulus G″ (red) as a function of temperature in heating processes for a 1 wt % MC solution. (c) Illustrative DSC trace for 1 wt % MC solution on heating. (d) The temperature-dependent G′ value curves for MC with different concentrations.


The DSC curve, curve C, is a differential scanning calorimetry curve, which shows the transition temperature at which the electrolyte converts from a liquid into a gel. This temperature is comfortably low.

And finally, a nice picture of stuff in their lab by which they do the testing:



The caption:

Figure 6. (a) Illustration of thermal switching behavior of the coin cell supercapacitor using 1 wt % MC solution-based electrolyte: digital photographs show the decreased light intensity of the LED while heating to 70 °C. (b) The reversible specific capacitance summary of thermal-responsive supercapacitor cycling between 25 °C and shutdown. (c) Ionic conductivity response to temperature of 1 wt % MC solution-based electrolyte.


Interesting work, I think. If we must waste energy by storing it, let's try to do it safely at least.

Now of course, I fully recognize that our concept of "safety" is a function of selective attention. I recall a mindless fool here, for example - whose happily made it to my "ignore" list - who focused on the "major news" that a tunnel at the Hanford Nuclear Weapons site collapsed, which in his tiny brain "proved" that nuclear energy was "unsafe," while so called "renewable energy" was without risk.

And of course, people couldn't care less if Tesla cars for billionaires and millionaires catch fire, or if computer batteries bring down planes.

I submit that this kind of thinking is the reason we are at 412 ppm and out of time. It didn't have to be this way, but it is.

All this said, I applaud the fact that these Chinese scientists, if not the general public here in the United States and indeed around the world, are paying attention to risks that are real as opposed to those that are inflated.


Have a pleasant Sunday afternoon.


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