… Scientific Illustration, by Asa Smith.
Last week I posted a story from kestrel about her rescue of a hummingbird. A few days later, this video crossed my desk, and it explains why the bird was likely so calm – torpor, which is a bit like going into a coma when you sleep. The video also covers a lot of general information about hummingbirds, focusing on their perfectly adapted and unique tongues. This channel is a bit irreverent, but their videos are humorous, engaging and well researched.
My goal in mcgyvering a vacuum pump was to remain under 100,-€ – which I did – and get better results than I have achieved with my shop-vac setup – which I did too. Still, I do not know whether to be disappointed or satisfied.
I wanted to utilize things that I already have, which includes several water pumps that are used to water bonsai trees and vegetable beds in summer and pumping water out of the cellar in the winter and some spare piping from house renovations. So I had to buy only the things for making the vacuum pump itself – in combination with a water pump, the best option seemed to be something based on the venturi principle.
So I went and bought these parts:
The parts were connected to each other more or less in the order as they are laid out on the picture. The black plastic hose connector was fitted into the brass one to lower its inner diameter. The brass hose connector right next to the right side of the chrome T junction is the inlet nozzle – I have glued an old tip from a silicone sealant tube (not depicted) in it to get the position and size of the nozzle correct. Into the upper brass hose connector was glued the white plastic 6 mm hose connector for the air suction.
So water comes in the T-junction from the right, gets squeezed through a nozzle which sprays into a slightly bigger opening in the outlet left, behind which is again a big pipe. The spray drags with it the air surrounding the nozzle and that way achieves suction through the top of the T-junction.
I am not able to write-up complete how-to, but this is the final product up and running in a vat of water.
The bubbles show it is working. When I connected the suction tube directly to a new vacuum manometer, I got a suction of whopping 0,6 bar, which did really impress me. Unfortunately, I do not get anywhere near that when I connect everything to the jar. After a few minutes, it stabilizes at this.
0.22-0.25 bar is still a bit more than what the shop-vac could achieve (which was 0.2). So it is usable and it is a definitive improvement because unlike the shop-vac it can run non-stop with zero risks of overheating anything, and it also makes nearly no noise, so a win there too. But when it achieves this, it still bubbles, so it still draws air. And when I close both ball-valves on the lid (one ball-valve is for pressure release, one for the suction), I start losing pressure in the jar really quickly. That tells me that the jar is not properly sealed and this here is not the maximum this setup can achieve, but an equilibrium between the pump and the improper sealing.
I had to make a new lid from five layers of plywood for this, with two ball-valves and the manometer, so there was a lot of potential for failure. But I did use water/airtight plastic sealant for everything and I went over all connections once more, yet I still cannot identify the leak(s). If it was a pressurized container, I might find the leaks with help of soapy water looking for bubbles, but I do not know how to check vacuum tightness.
So this is where I am now and this is where I leave this be for a few days at least. It has occupied me for three days already, time to go back to making knives.
When I was hardening the blades two days ago, I have tossed in there six cut-offs as well and I have used different methods to quench them. After that I had still one piece left so I have heated that up to the 1050 °C and let it cool in the forge. Then I performed some tests and the results are very interesting.
These are the samples and methods used (marked by the number of notches on the edge):
0 – left to cool in the forge
1 – untreated
2 – left to cool in the air
3 – quenched between Al plates only
4 – oil
5 – water
6 – AL plates + water + Freezer fro 2 hours
None of the samples were subsequently tempered, so they should be at peak hardness.
With the sample size just 1 piece per method I cannot of course perform too many tests. The idea was to polish the samples – which I did. And already during the polishing, I have noticed that all samples seem to be hardened, except #1.
The next step was supposed to be to etch the surface and look at the structure under a microscope. Well, that did not work at all, and the reasons are a mystery to me. Just as it happened with the knives last time, it happened again here – the electrochemical method worked on some samples perfectly, but completely failed on others. I was unable to solve the problem. Another thing was that my microscope apparently does not have big enough magnification to see a difference between the original steel and the quenched one. I could re-build it and improve it about ten times, but I am still not sure if that would be enough and I do not want to get sidetracked to that now, it would be probably more than one day of work and I have already spent two days having fun instead of working.
So I did what I could with samples of this geometry. First trying to scratch them with my hardness measuring gages .
sample # 1 could be scratched by the lowest 38 HRC gage, which was to be expected.
All samples except # 1 could not be scratched by the 62 HRC gage, so they are at hardness 62 HRC or more. Which is something I did not expect, especially not of # 0, which was left to cool in the forge – and that took definitively several hours. I was expecting this sample to be harder than the new steel, but not hard enough for a knife – but it evidently is more than enough hard for a knife, hardness 62 is in fact quite excessive.
Secondly, I have tried scratching the samples against each other, and the results became even more interesting. All samples could scratch # 1, as expected. But none could scratch #4 and #4 did scratch all, whilst the remaining five could not scratch each other, so they are all of the same hardness.
Thirdly I have put the sharpest angle of the triangle approx 10 mm into a vise and break it off. #1 has bent easily, as expected, all others have snapped off.
What can I deduce from this? Several things.
It would be interesting to see what is the exact influence on toughness/strength once tempered. I could not find it, so I will have to test it myself. But for that, I will need another sample geometry. So maybe next time.
All in all, the N690 seems to be pretty remarkable steel. It does not have the label (and price tag, otherwise I could not use it) of “super steel”, but it is no wimp either and apparently is not very fussy about the heat treatment, apart from the requirement to heat it above 1050°C.
My personal view of the coronavirus is that outside of China, the mortality rate might significantly rise above what it has now (which is already several times higher than influenza), just as it did with the swine flu pandemic in 2009 (which my sister barely survived, but luckily nobody else in the family got). My reasoning for this is – people in China were probably at least somewhat exposed to the said virus in its non-human-infectious form, or some of its less dangerous relatives, which would give them at least partial immunity. Once the virus spreads to populations that have no immunity to its or to viruses similar to it, it will become much worse.
Since it is a pulmonary disease, our whole family is especially susceptible and in danger, since all of us have asthma, my parents are elderly, my sister has already damaged lungs and my brother is a heavy smoker. I certainly hope not to encounter it, I already had viral bronchitis this year for two weeks and I did not enjoy it in the least.
I often listen to podcasts when I walk Jack, and I’ve found a new one that I think you’d really like, too. It’s called ‘Ologies’ and the host Ali Ward is an Emmy award-winning science journalist. She’s worked on such shows as ‘Brainchild’ (Netflix), ‘How to Build Everything’ (Science Channel) and ‘In The Wild’ with co-host Adam Savage of Mythbusters.
Alie Ward is a charming and humorous host, and every week, she interviews a scientist from a different ‘Ology’ or specialty area, and questions them on what their field is all about. She approaches each subject with a genuine sense of curiosity and wonder. What you hear as the end product is a bunch of scientists who are passionate about their work telling stories and talking about what they love. Each interview ends with a lightning round of questions sent in by her patrons. One of her mottos is, “Never be afraid to ask a smart person a stupid question.” Or a smart one, either – Alie, herself, has a science background and prepares well for each interview, so the conversations are compelling and intelligent with a pleasant touch of humour. As an interviewer, she allows each guest space and time to tell their best stories in that passionate way of nerds.
‘ Ologies’ is Alie’s own brainchild, something that she thought about doing for many years before finally putting it together. There are currently over a hundred ‘Ologies’ available and Alie intends to keep going. She also makes a donation on each show to the charity of the Ologists choice and then features the charity on her website. I’ve been binging on it for about 2 weeks, and I’m hooked. Give it a listen. This is the website for the show, and you should be able to find it via most podcast players.
There’s one more reason to love trees. A new study from The Crowther Lab, ETH Zurich, published in the Journal of Science, July 2019, says that targeted reforestation could isolate 2/3 of human-made carbon emissions and would be the best way to mitigate the effects of climate change.
The researchers calculated that under the current climate conditions, Earth’s land could support 4.4 billion hectares of continuous tree cover. That is 1.6 billion more than the currently existing 2.8 billion hectares. Of these 1.6 billion hectares, 0.9 billion hectares fulfill the criterion of not being used by hu-mans. This means that there is currently an area of the size of the US available for tree restoration. Once mature, these new forests could store 205 billion tonnes of carbon: about two thirds of the 300 billion tonnes of carbon that has been released into the atmosphere as a result of human activity since the Industrial Revolution.
Calculations were made based on current conditions and cities and agricultural areas were not included because those areas are necessary to support human life.
According to Prof. Thomas Crowther, co-author of the study and founder of the Crowther Lab at ETH Zurich: “We all knew that restoring forests could play a part in tackling climate change, but we didn’t really know how big the impact would be. Our study shows clearly that forest restoration is the best climate change solution available today. But we must act quickly, as new forests will take decades to mature and achieve their full potential as a source of natural carbon storage…. The study also shows which parts of the world are most suited to forest restoration. The greatest potential can be found in just six countries: Russia (151 million hectares); the US (103 million hectares); Canada (78.4 million hectares); Australia (58 million hectares); Brazil (49.7 million hectares); and China (40.2 million hectares).
I encourage you to check out the Crowther Website where you can read the report in full. The site also offers a tool that allows you to pinpoint any area on the globe to find out about its reforestation potential.
via: Science Daily
One of my favourite perspectives for photographing trees is looking up, way up, because a tall tree silhouetted against the sky is majestic. In winter their uppermost bare branches create beautiful patterns in the sky that look sculptural to me. Some trees, though, create sculptural bare spaces in the summer, too, through a phenomenon known as “crown shyness.”
If you look up toward certain types of towering trees—including eucalyptus, Sitka spruce, and Japanese larch—you may notice a unique phenomenon: the uppermost branches don’t touch. Known as “crown shyness,” this natural occurrence results in rupture-like patterns in the forest canopy that seem to perfectly outline the trees’ striking silhouettes.
Numerous scientists have been studying crown shyness since the 1920’s and several theories have been put forward, but no one knows for certain what causes it.
One possibility is that it occurs when the branches of trees (particularly those in areas with high winds) bump into each other. Another suggested explanation is that it enables the perennial plants to receive optimal light for photosynthesis. Perhaps the most prominent theory, however, is that the gaps prevent the proliferation of invasive insects.
My favourite theory is the one that postulates the trees are trying to avoid bumping into one another. It seems so polite and I can imagine woody conversations along the lines of “oops – so sorry old chap – didn’t mean to crowd you. I’ll just move over here.”
I think it’s stunning and hope I get a chance to see it someday. If you’re lucky enough see it, please take a photo and share.
Here’s one last photo from the story, but I encourage you to check out the full story and look at all the photos. The link is below.
The full story and more photos are at: My Modern Met
My thanks to rq for sending this story my way.