kumarski

5 ms·

31.
The Role of Social Media in Cartel Recruitment(csis.org)
4 points by kumarski 1y ago|0 comments
32.
Mysterious Case $15B Startup and Its Anonymous Multi-Billion Dollar Investor(forbes.com)
5 points by kumarski 1y ago|0 comments
33.
by kumarski 1y ago
Don't have time to reply to everyone. Clearly triggered a lot of programmers here, so I'll try to go point by point. Electric motors are ~3× more efficient, but the crushing 18:1 energy density disadvantage (170-180 Wh/kg usa
34.
by kumarski 1y ago
Full lifecycle comparison included both systems https://www.journals.elsevier.com/journal-of-transport-econo...
35.
by kumarski 1y ago
System-level efficiency negates motor advantage https://www.sae.org/publications/technical-papers/content/20...
36.
by kumarski 1y ago
Hydrogen buses limp at an EROI of 0.5 to 1.5. Losses via Gibbs free energy (237 kJ/mol to split H2O) and compression (20% of H2’s 120 MJ/kg.) Barely cash in on the H2-O2 reaction (ΔH = -285.8 kJ/mol). Battery buses, powered b
37.
by kumarski 1y ago
I directly compared them in visualization 6 ($75-110/kWh conventional vs. $245-380/kWh lithium, all externalities included). Electric ekranoplans would be badass, and sealed motors solve one problem, but battery chemistry is the r
38.
by kumarski 1y ago
<2.5% of US vehicles are electric. I bought $AMR, $FCG, $UAN, and $POWL. I bought $TSLA and sold almost at the top as well, but for different reasons than fundamentals. (Greenback boomerang CCP dollars etc...) Chemistry doesn't lie
39.
by kumarski 1y ago
Factor in complete system requirements—cooling, casings, and safety systems—that 270 Wh/kg battery delivers only 170-180 Wh/kg of usable energy. Jet fuel still maintains an 18-19× energy density advantage (3.2 kWh/kg vs. 0.17
40.
by kumarski 1y ago
former engineer, but w/e.
41.
by kumarski 1y ago
HSR infrastructure costs $50-80 million per kilometer in developed countries. :(
42.
by kumarski 1y ago
At 10-15% conversion efficiency, you're burning 85-90% of your energy just making the damn fuel, requiring 6-7× more renewable infrastructure than direct electrification. Current production costs are $15-25/gallon (not the fairy t
43.
by kumarski 1y ago
Density is a must have in our civilizations....
44.
by kumarski 1y ago
fair point, but most people don't open up chemistry books.
45.
by kumarski 1y ago
impractical, the number of ships to install these things is already constrained, not to mention the dispatch, repair, and transmission costs.
46.
by kumarski 1y ago
The energy required to extract, process and manufacture lithium batteries (70% of total lifecycle energy occurs before the vehicle moves) Grid transmission losses (5-8% average, up to 15% in extreme conditions) Battery charging/dischar
47.
by kumarski 1y ago
Sulfur Hexafluoride and Nitrogen Trifluoride proliferate under a CO2 minimization regime. Nobody is arguing with Arrhenius proofs. Nitrogen trifluoride (NF3) is a potent greenhouse gas with a global warming potential (GWP) of 17,200 over a
48.
by kumarski 1y ago
Yes.
49.
by kumarski 1y ago
Fair point, check the post again, I've posted on twitter about the benchmark for productively profitable venture and PE dollars. It's our taxpayer dollars at work. As a public market pegged to the same grid constraints, I prefer $
50.
Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably(kumarletter.com)
64 points by kumarski 1y ago|202 comments
51.
License to Kill(calmatters.org)
7 points by kumarski 1y ago|1 comments
52.
by kumarski 2y ago
https://www.slideshare.net/slideshow/the-hydrogen-myth-prese...
53.
by kumarski 2y ago
A new synthesis pathway.... Once in a blue moon or every decade....these folks wrangle differently...finding the bleeding edge that everyone overlooks.
54.
Stereoretentive Cross-Coupling [pdf](chemrxiv.org)
2 points by kumarski 2y ago|1 comments
55.
Timing and Periodicity of Influenza Epidemics(pmc.ncbi.nlm.nih.gov)
2 points by kumarski 2y ago|0 comments
56.
Chat GPT in Seconds Shreds Years of Minnesota State Pension Fee Disclosures(pensionwarriorsdwardsiedle.substack.com)
2 points by kumarski 2y ago|0 comments
57.
Repairing California Without Fixing the Ballot Process Is Impossible(kumarletter.com)
2 points by kumarski 2y ago|0 comments
58.
India's Internet Capacity to Increase 4x by 2025 with These Three Cable Projects(swarajyamag.com)
1 points by kumarski 2y ago|0 comments
59.
Fiber optics to keep elephants and trains safe across Indian Railways East Coast(news.railbusinessdaily.com)
19 points by kumarski 2y ago|0 comments
60.
by kumarski 2y ago
I think it's irrelevant if the cost of solar panels goes to zero, the reality is that the farm to fork cost/kwh is still quite high because dispatch and transmission are never cheap. Furthermore, for every 1 pound of polysilicon p

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