mreiner
Paraphrased:
- push-pull ventilation is easy to install and comparatively cheap
- it's prone to hygiene issues like blowing dirt out of the filters back into the air and providing a moist environment for microorganisms in some operational conditions
- it's prone to windy conditions
- the numbers stated by commercial vendors seem to have no basis in reality, there seems to be no vendor providing data based on the relevant testing standard for these systems. OPenERV states they want to get it tested by Passivehause institute but also say no lab data measured yet.
Might be just my counter-factual gut-feeling, maybe a mechanical window opener based on EspHome for short pulsed passive ventilation intervals is actually more efficient, easier to implement and need less maintenance? Not aware of any comparisons though and last time I checked I could only find some finicky 3d printed actors that might not survive a guest opening the window.
There are many factors driving weigth loss or gain, the macronutrients per se seem to be irrelevant in the long term though: https://pubmed.ncbi.nlm.nih.gov/19246357/
There are health risks involved in low/no carb diets and the article mentions none of those.
Consider you need to create a fair pressure gradient between the two sides of the filter and it needs to be higher the more the filter clogs up. AFAIK radial fans are more efficient for that purpose. Downside is the noise.
If you are running the ceiling fan anyway just for the turbulence it creates on a hot day, it's probably fine even if just a small percentage of the airflow is pulled through the filters, your data certainly looks promising.
A test has a specific sensitivity and a rate of false positives. So for screening (CT in this case) you would want a high sensitivity and low cost, while the false positives would not be your priority. The positives should go through a confirming test (biopsy in this case) with a high specificity. Here cost and sensitivity are usually secondary.
Now insurers look at the screening tests rate of false positives. If they deem it too high, they don't want doctors to do those tests on a population with a low probability of having the condition you are screening for (low base rate). If the patient belongs to a subgroup shown to have a high enough base rate of a condition, then it makes sense to do the screening.
Then you have different patients, some want to get one MRI each year, some only want to run diagnostic after they experience symptoms. I believe most doctors respect that individual risk tolerance within the given framework.
Now the thresholds obviously should be revised regularly as cost, test properties and even base rates of diseases change, but I don't see a systemic defect here, my blind spot?
IMHO he shrugs of the main issues without discussing in on the technical level you would expect for the risks involved here. He basically argues politics should trump engineering realities to cut corners. While this is usually fine in a startup environment, it's a bad idea for environments like space, healthcare, aviation or nuclear. We all know how it worked out for Boeing recently.
I would really like to see the numbers if you remove some of the heavy industry we don't need to keep running in Europe. This load removed, how much of the remaining base load throughout the hole year is really provided by gas, as this is the true load that could possibly be replaced by nuclear, from 2023 onwards if I may believe other comments.
I'm curious, but I find it hard to believe this would do anything for our friends in Ukraine NOW, so if this is our concern we should probably talk about other levers instead of recycling the nuclear debate.