http://www.mdpi.com/1996-1073/9/8/622/htm a 2016 #paper on #solar #energy payback times and EROEI (“EROI”) and life-cycle analysis (LCA) and net energy analysis (NEA). In particular fixed ground-mounted “multicrystalline” silicon #photovoltaic cells have EPBT of 0.9 to 2.1 years depending on irradiation (insolation), and an EROEI of 15 to 35. This is surprising because that’s pretty much what it was when NREL published an EPBT analysis around 2001 or so.
https://www.mdpi.com/1996-1073/2/1/1/htm “#Energy Inputs in #Food Crop Production in Developing and Developed Nations,” Pimentel’s #EROEI #paper where he found about four joules returned per joule spent on industrialized #agriculture, #CC-BY, Energies 2009, 2(1), 1-24; https://doi.org/10.3390/en20100001
https://www.mdpi.com/1424-8220/21/2/438 Elfring, Torta, and van de Molengraft’s more comprehensive #particle-filters #tutorial #paper (with #PDF) which supposedly has example code that I can’t find. This is recent (02021) and open-access (#CC BY, I think), and many pages long, and has an overview of a lot of the motivation, but in some sense not very approachable.
https://www.mdpi.com/2075-163X/12/2/220 #CC #paper describes various excavation methods (plasma, foam injection, etc.) including #expanding-grout, which it says works by hydrating lime under confinement and also producing ettringite, but lists four different types: type K (4CaO·3Al₂O₃·SO₃ + 8CaSO₄⋅H₂O + 6Ca(OH)₂ + 74H₂0 → 3(3CaO⋅Al₂O₃⋅3 CaSO₄⋅32H₂O, can be enhanced with silica fume and plasticizer), type M (CaO⋅Al₂O₃ + 3CaSO₄⋅H₂O + 2Ca(OH)₂ + 24H₂O → 3CaO⋅Al₂O₃⋅3CaSO₄⋅32H₂O), type S (3CaO⋅Al₂O₃ + 3CaSO₄⋅H₂O + 26H₂O → 3CaO⋅Al₂O₃⋅3CaSO₄⋅32H₂O), and class [sic] G (CaO + H₂O → Ca(OH)₂). Calls it “SCDA” and mentions ASTM C 845 “Standard Specification for Expansive Hydraulic Cement”. It says they work too slowly (12h) to replace explosives in the usual mining cycle, but I suspect that’s not true of class G, where the main problem is keeping it from reacting to completion before you can pour it into the hole.
i don't think mdpi is a scam publisher, but then, i don't read mdpi papers from following some kind of latest-mdpi-papers feed; i read them because other papers cite them, so i couldn't tell you if the utter-bullshit-paper percentage on mdpi is 1% or 99%
i just know i heave a sigh of relief when the paper i'm looking for turns out to be on mdpi, because i know that not only will i be able to read it without hassle, it will have a clearly marked creative-commons license that permits me to archive and redistribute the paper. same with hindawi actually, though i'm mmaybe a bit prejudiced against hindawi papers