As it's almost the #Equinox, the #Sun is setting virtually due #West these days. This #sunset is a bit deceptive as it seems to show heavy #mist with the sun's disc very diffuse and almost invisible. Actually, the sky is relatively clear towards the #zenith. Still, I do like the layered progressive #haziness of the land.
This is the last week of #summer but today is hot and #sunny and so the #pollinators are out doing their thing before it gets to damp and dark and the #flowers wither away. In the front #garden, one of the #plants attracts a lot of #bees and #hoverflies. Here are some pictures I took with my #camera using a #MacroLens.
I'm not sure whether this is a #Bee or a #HoverFly.
You can see the #PollenSacs on this #Bee.
#MyWork #MyPhoto #CCBYSA #DSLR #Nikon #D7000 #Macro #Horticulture
As #summer is coming to and we're heading towards #autumn, the #garden is bearing some #fruit which add #colour to the surroundings.
This #squash is about 25 cm long and has turned a very nice #orange #hue.
These #green #grapes are nearly ripe and the #Vine #Leaves are also used in #cooking.
These #blackberries are at various stages of ripeness.
Here are some #cattle resting in the garden. Just kidding! That's from my recent trip to #Dartmoor and have nothing to do with me except that I photographed them.
As it's a #BankHoliday #weekend, we went on a hike on #Dartmoor. I planned it to be a visit to somewhere I hadn't been before but starting off from a familiar location. In total, the excursion was 18 km of walking and took the best part of 6 hours with all the stops and breaks. As anyone who has walked here before knows, it's not to be done without preparation and having a good #map and #compass with you is vital. Mobile phone reception is patchy at best and so I rely on a paper map and the tried-and-tested method of #DeadReckoning. Essentials include a pair of good quality #WalkingBoots, #WaterProof clothing available and you should always prepare to be colder than you would be in town. As the terrain is quite rough and the vegetation can be thorny along with the presence of insects, #Shorts are not recommended unless you're happy to have grazes and bites by the end of the trip. The elevation is between 400-500 m above sea level and it is one of the wettest places in #England. It is also exposed to high winds.
The start of the journey was easy enough, just a short climb up to a #Cairn.
Until you join a #path or #bridleway, you have to negotiate #gorse which, if you're not careful, could easily mean a twisted ankle. However, the wild #flowers are very colourful. You can also see part of #FernworthyForest in the background, which is where we were headed.
On the way to our first target, there were some #Neolithic artefacts such as these #StandingStones. There are some wild #DartmoorPonies in the background and I took a zoomed-in image of one of the ponies -- it's best not to get too close to them.
The first destination on the itinerary was #FernworthyReservoir. It has a #MasonryDam, which is not a common form of #Dam, most being concrete or earth (embankment) dams in the #UK. There is a another one in Dartmoor and so I'm guessing there was a trend to build such types at the beginning of the twentieth century, which is when I happen to know the other one was built. Neither the dam nor the #reservoir are very big but they do provide water for nearby populations.
The surface of the reservoir was quite choppy owing to the windy conditions. Also, the level was near the maximum and right up to spillway at the centre of the dam.
Fernworthy Forest is a #conifer forest, which I think is not natural, rather being there to provide timber. There are many track through it but none are marked and so the only way to find out which way you're going is to use a compass. I was uncertain of my precise location after a while but I knew that if we kept heading in a westerly direction, we'd eventually get to the other side.
Once out of the forest, it was a matter of heading south towards the main road. The weather forecast was spot on and it started to rain right on cue. Once over a rise, eventually we found a bridleway down.
Once we passed this #StoneCircle, I knew we were on the right track as it's marked on the #OSMap. The journey from there was quite straightforward, although still another 5-6 km to go.
The last leg of the journey was on a main road, without a separate footpath but just before getting onto that, I looked at the path we'd taken and also to the other side of Dartmoor.
#MyWork #MyPhoto #CCBYSA #DSLR #Nikon #D7000 #Summer #Countryside #Moorland
About one or two weeks ago I managed to perform some #Urbex nearby some universities. Both at complete night and at sunset. The place was ... Empty. But it has the vibe I like the most : Brutalist ruins reclaimed by nature. Not to mention there was a bonus place: A destroyed abandoned where the rooftop was torn apart.
I did not take pictures at night but let me tell you the view from the rooftop of the main building was beautiful.
#ccbysa #urbex #abandoned #ruins #decay #nancy #lorraine #photographies #pictures #nikon #artwork #freeart #artlibre #free #libre #art #diaspoart #darktable #diaspoart
It may be a bit soon but I've produced a #calendar for #2025. Unlike previous editions, which featured some of my photographs, this one contains #illustrations to do with #mathematics, #geometry, #physics and #engineering applications.
Yesterday, I posted an image of the #LorenzAttractor showing the evolution of three trajectories (shown in red, green and blue) starting close together. Here, I've made it into a little animation to show how the paths initially stay close to each other but after about a quarter of the duration plotted, they #diverge from each other irrevocably (i.e. become uncorrelated) but remain part of the #ChaoticAttractor.
#DynamicalSystems #ChaoticAttractors #StrangeAttractors #NumericalSolutions #Mathematics #AppliedMathematics #CCBYSA #FreeSoftware #WxMaxima
Just messing about a bit. Here is the famous #LorenzAttractor plotted using #WxMaxima. The three #trajectories, shown in red, green and blue are for three fairly nearby #InitialConditions.
#DynamicalSystems #ChaoticAttractors #StrangeAttractors #NumericalSolutions #Mathematics #AppliedMathematics #CCBYSA #FreeSoftware
This pair of #Swans and their juvenile #Cygnets have set up a resting spot on the banks of the #Canal and on the edge of the shared #Cyclepath and #Footpath. I'd passed them before but didn't have a camera with me at the time. As you can see, they have no concerns with people being quite close by but someone told me that they've been quite aggressive, no doubt if someone has been perceived to be a threat.
Yesterday, we went on a trip to #Penzance in #Cornwall. There is a direct #RailwayLine running from here to #London #Paddington. My local station is about half way along this 6-hour route and I've been on the London leg many time and so I thought it would be nice to go to the end of the line in the other direction. There are lots of #RailwayStations with strange names, like #Lostwithiel and #StErth and so it was nice to pass through them on our way.
Looking east along the beach, you can see #StMichaelsMount, which is built on a part-time island, in that it is an island when the tide is in but otherwise you can walk to it over a #causeway. We did that a decade ago. Here are a couple of views with a #ZoomLens (I didn't have space to pack my telephoto lens).
The #town of #Penzance can be seen in the opposite direction.
Parts of the #beach have #grey compacted sand. It's firm and yet soft and when wet it forms a shimmering mirror for the sky.
From the next #headland, you can get a really good view of St Michael's Mount. I think the light conditions here were better too in the early afternoon.
Off the shore, there were several #vessels including this #ship. I'm not sure what its function is but it's certainly for some special purpose.
The #sea appeared #blue or #green depending on the underlying geology.
Here. it even has patches of gold colour looking a bit like those pools into which people drop coins.
The boundary of #Devon and #Cornwall is marked in the south by the #RiverTamar. Across it, there is an old and historic #RailwayBridge called the #RoyalAlbertBridge, which was built in the mid 1800s by #Engineer #IsambardKingdomBrunel, Here, you can see it on the approach on the #train. This was taken using my #Android phone.
Right next to it is the much more modern #RoadBridge, which is a #SuspensionBridge.
Following on from yesterday's posting of flow around a #ZhukovskyAerofoil, I've added #equipotential lines (blue) in addition to #streamlines (black). The two families are #contours of the #real and #imaginary parts of an #AnalyticFunction and therefore have the property of intersecting #orthogonally. The plots aren't ideal as there is some anomalous features where the equipotential lines are very close to the #aerofoil but it's still not bad.
Here, each frame is a different #wing profile, obtained this time by keeping the imaginary eccentricity of the generating #circle constant and varying only the real part.
#MyWork #CCBYSA #AppliedMathematics #Aeronautics #Aerodynamics
The #Zhukovsky #Aerofoil (sometimes transliterated as #Joukowsky from #Russian), is a 2D model of #streamlined #Airflow past a #wing. It uses #ComplexVariable and is an #AnalyticFunction (i.e. #Differentiable everywhere, save at isolated #Singularities). Take a circle in the #ComplexPlane which is not quite centred at the #origin but passes through the #coordinate (1,0) or (z=1+0i). Using the mapping w -> z+1/z, you get something that looks remarkably like an #aerofoil.
It is a #ConformalMapping meaning that angles are preserved during the mapping. In this animation, I've varied the imaginary part of the the eccentricity, while keeping the real part the same. With a zero #AngleOfAttack, you can see the change in the airflow around the #wing as its shape changes.
#MyWork #CCBYSA #AppliedMathematics #WxMaxima #FreeSoftware #Aeronautics #Aerodynamics #LaminarFlow
J'ai un milliard de truc à vous montrer en retard ...
Pour commencer deux #illustrations à l'occasion de la sortie de #VenC 3.2.2 dont l'annonce a été mise en ligne sur LinuxFR. On se revoit vite pour la suite !
Bisous & data love
#linux #venc #web #python #sitestatique #logiciellibre #freesoftware #floss #art #freeart #artlibre #gimp #artwork #digitalpainting #ccbysa #creativecommons
I like the #flowers of this #plant but it is growing out of a gap in #concrete by the porch and garage. I think it must have propagated from a neighbour's #garden many years ago. I tried to take a cutting and plant it in some soil in the back garden but it withered away. Evidently, it only likes rocky conditions. Can anybody tell me the species?
One of the disadvantages of a fine day is that the #HighPressure keeps #dust and #pollution trapped at lower levels of the #atmosphere. This makes #visibility poor. Not far off sunset and you can see a layering effect in the mid and #background with the #horizon barely visible in the #haze.
A high-speed road or railway track that is poorly designed. The vehicle moves at constant speed from the straight segment of road or track directly onto a CircularArc and thereby encounters an instantaneous application of centripetal acceleration. This is neither good for the driver and passengers who will feel a sudden force outwards, nor for the vehicle which my skid and impose large stress changes in the axles and bearings.
This is why #Engineers use #TransitionCurves in the form of #CornuSpirals or #Clothoids to connect from the straight segment onto a circular arc. It has the property that it starts with zero #curvature at the beginning and then the curvature increases linearly with distance travelled along the curve. At the appropriate curvature, it is connected to a circular arc with the same curvature. The people in the vehicle and the vehicle itself are much less stressed by this solution.
#MyWork #WxMaxima #CivilEngineering #HighwayEngineering #CCBYSA
Forgive the recent apparent obsession (I'd call it a fascination) with the #cycloid but I've just discovered something I'd not heard of before. It is also called a #TautochroneCurve or #Isochrone curve, which means that a particle starting from any location on the curve will get to the #MinimumPoint at precisely the same time as a particle starting at any other point.
Here's an #animation I wrote today in #Maxima which illustrates the property.
#Dynamics #Kinematics #Mathematics #AppliedMathematics #Mechanics #ClassicalMecanics #WxMaxima #FreeSoftware #MyWork #CCBYSA
After lunch yesterday, we went to the #HistoryOfScienceMuseum in #Oxford. It's not very big but contains some really fascinating exhibits. It is right next to the #SheldonianTheatre and well worth a visit.
Here are wooden models of the #FivePlatonicSolids.
This is a beautiful example of #HandWriting in a book. #Writing like this is certainly a lost art these days.
Here I am explaining to my spouse the similarities and differences between #Octants, #Sextants and #Quadrants.
This wooden box contains some immaculate #brass #DrawingInstruments. Another rarity these days but I do remember learning how to use similar #instruments while studying at university.
A brass #sundial.
Without anything but manual #SurveyingEquipment, humans were able accurately to map out the entire globe. It's amazing what can be achieved when humanity works together. But also, this model is absolutely gorgeous.
Not to be outdone, the #astronomers mapped the #sky and here it appears on a companion globe.
No computers were around then but the ingenuity of humans to develop calculating instruments to allow them to crunch numbers meant the creation of some devices of stupendous cunning.
To this day, trainee pilots have to master the #CircularSlideRule in order to do calculations for various tasks. Before flying was ever developed, such #SlideRules were in common use.
This #camera is another fine example of hand-made instruments. The craft and skill of whoever made it is a marvel.
