Acoustic measurement refers to the process of quantifying various sound-related parameters in a given environment. These measurements are critical in various fields, including engineering, environmental science, music, architecture, and health. The following are common aspects of acoustic measurement: 1. **Sound Pressure Level (SPL)**: Measured in decibels (dB), this quantifies the pressure of sound waves in the air relative to a reference level.
A-weighting is a frequency weighting used in sound measurements to reflect the relative loudness perceived by the human ear. The human auditory system does not respond equally across all frequencies; it is more sensitive to mid-frequency sounds (typically around 1 kHz to 4 kHz) and less sensitive to very low and very high frequencies.
Acoustic radiation force is a phenomenon that occurs when an acoustic wave, such as ultrasound, interacts with an object or a medium. It results from the pressure variations produced by the sound waves as they propagate and can lead to a net force acting on small particles, bubbles, or biological tissues within the medium. ### Key Aspects of Acoustic Radiation Force: 1. **Mechanism**: When an ultrasound wave passes through a medium, it generates regions of high and low pressure.
Bought December 2023 for 300 pounds, so 15 pounds / TB. Needs power supply unfrotunately besides USB, the largest one without needing power supply was only 5 TB at the time so not worth it, given that my P14s alreay carriers 2 TB. 10x is a must for the external crap.
www.westerndigital.com/en-gb/products/external-drives/wd-elements-desktop-usb-3-0-hdd?sku=WDBWLG0030HBK-EESN (archive)
Noise: it has a constant pleasant hum, with a not so nice click every 5 seconds or so. Reasonable, but not amazingly incredible.
The size is reasonable, not megaportable, but definitely reasonable.
The natural sciences are not just a tool to predict the future.
They are a reminder that the lives that we live daily are mere illusions, religious concepts such as Maya and Samsara come to mind.
We as individuals perceive nothing about the materials that we touch every day really work, nor more importantly how our brain and cell work.
Everything is magic out of our control.
The natural sciences allow us peek, with huge concentrated effort, into tiny little bits a little of those unknowns, and blow our minds as we notice that we don't know anything.
For all practical purposes in life, there is a huge macro micro gap. We are only able to directly perceive and influence the macro events. And through those we try to affect micro events. Because for good or bad, micro events reflect in the macro world.
It is as if we live in a different plane of existence above molecules, and below galaxies. The hierarchy of Figure "xkcd 435: Fields arranged by purity" puts that nicely into perspective, shame it only starts at the economical level, not going up to astronomy.
The great beauty of science is that it allows us to puncture through some of the layers of reality, either up or down, away from our daily experience.
And the great beauty of artificial intelligence research is that it allows to peer deeper into exactly our layer of existence.
Every one or two weeks Ciro Santilli remembers that he and everything he touches are just a bunch of atoms, and that is an amazing feeling. This is Ciro's preferred source of Great doubt. Another concept that comes to mind is when you see it, you'll shit bricks.
Perhaps, the feeling of physics and the illusion of life reaches its peak in molecular biology.
Just look at your fucking hand right now.
Do you have any idea of each of the cells in it work? Isn't is at least 100 times more complex than the materials of the table you hand is currently resting on?
This is the non-science fiction version of the lotus-Eater Machine.
Alan Watts's "Philosopher" talk mentions related ideas:
The origin of a person who is defined as a philosopher, is one who finds that existence itself is exceedingly odd.
The toddler of a friend of Ciro Santilli's wife asked her mum:Our perception of the macroscopic world is so magic that children have to learn the difference between living and non-living things.
James Somers put it very well as well in his article I should have loved biology by James Somers, this quote was brought to Ciro's attention by Bert Hubert's website[ref].The same applies to other natural sciences.
I should have loved biology but I found it to be a lifeless recitation of names: the Golgi apparatus and the Krebs cycle; mitosis, meiosis; DNA, RNA, mRNA, tRNA.In the textbooks, astonishing facts were presented without astonishment. Someone probably told me that every cell in my body has the same DNA. But no one shook me by the shoulders, saying how crazy that was. I needed Lewis Thomas, who wrote in The Medusa and the Snail:For the real amazement, if you wish to be amazed, is this process. You start out as a single cell derived from the coupling of a sperm and an egg; this divides in two, then four, then eight, and so on, and at a certain stage there emerges a single cell which has as all its progeny the human brain. The mere existence of such a cell should be one of the great astonishments of the earth. People ought to be walking around all day, all through their waking hours calling to each other in endless wonderment, talking of nothing except that cell.
Alan Watts' "Philosopher" talk (1973)
Source. Lecture given at UCLA on 1973-02-21. Some key quotes from the talk:The origin of a person who is defined as a philosopher, is one who finds that existence itself is exceedingly odd.
Here is a vendor showcasing their device. They claim in that video that a single photon is produced and detected:
Concrete device described at: Video "How to use an SiPM - Experiment Video by SensLTech (2018)".
There is also a time-energy uncertainty principle, because those two operators are also complementary.
Introduction to Spintronics by Aurélien Manchon (2020)
Source. The Spin on Electronics by Stuart Parkin
. Source. 2013. Student Friendly Quantum Field Theory by Robert D Klauber (2013) by 
Ciro Santilli 40 Updated 2025-07-16
Ciro Santilli 40 Updated 2025-07-16This didn't really deliver. It does start from the basics, but it is often hard to link those basics to more interesting or deeper points. Also like many other Quantum field theory book, it does not seem to contain a single comparison between a theoretical result and an experiment.
Quantum field theory lecture by Tobias Osborne (2017) mentions that quantization is a guess.
Conditioned play audiometry (CPA) is a behavioral testing method used to assess hearing in young children, typically aged 2 to 5 years, who may not be able to respond to traditional audiometric testing methods like pure-tone audiometry. In CPA, the child is conditioned to respond to sounds by engaging in a play activity that requires them to indicate they have heard a sound.
The term "hypersonic effect" typically refers to the phenomena associated with objects traveling at hypersonic speeds, which are defined as speeds greater than Mach 5 (five times the speed of sound in air). When an object moves at hypersonic speeds, it experiences a range of physical effects due to the extreme velocities involved, including: 1. **Shock Waves**: At hypersonic speeds, the flow of air around the object generates powerful shock waves.
The Institute of Acoustics (IOA) is a professional body in the United Kingdom dedicated to the advancement of the study and practice of acoustics. Founded in 1974, the IOA promotes the interests of those involved in acoustics, noise, and vibration control, providing a platform for professionals across various sectors, including engineering, environmental science, architecture, and audio technology.
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 3. Visual Studio Code extension installation.
Figure 4. Visual Studio Code extension tree navigation.
Figure 5. Web editor. You can also edit articles on the Web editor without installing anything locally.Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.Video 4. OurBigBook Visual Studio Code extension editing and navigation demo. Source. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact