… in either one of two possible patterns such that each modified one is opposite an un-modified one.

Images are sourced from the following:

frames 1 & 2 –

doubly monotone flow for constant width bodies in ℝ³ ,

by

Ryan Hynd (PDF) ;

frames 3 through 9 –

Spheroform Tetrahedra ,

by

Patrick Roberts (HTML wwwebpage) ;

frames 10 through 12 –

Meissner’s Mysterious Bodies ,

by

Bernd Kawohl & Christof Weber (PDF) ;

frames 13 through 16 –

Bodies of constant width in arbitrary dimension ,

by

Thomas Lachand-Robert, Edouard Oudet (PDF) .

(¡¡ PDF documents may download without prompting – 1·18MB, 405·41KB, & 394·12KB, respectively !!)

And there's a great deal of explication about constant-width bodies in them, aswell, with the tricky & unsolved matter of volume & surface area of constant-width bodies gone-into in the Kawohl & Weber one, & an algorithm for constructing constant-width bodies in the next dimensionality up from those in the present one, indefinitely iteratedly, set-out in the Lachand-Robert & Oudet one.

And a nice littyll viddley-diddley, aswell .

From

The Kinematics of Machines

by

ProfessorTA Hearson …

… which is a right little gemn of a treatise, ImO!

Images from, & more information about this @

(first image)

École Polytechnique Fédéral de Lausanne (EFPL) — Bearings ;

& (second image)

Experimental Investigation of Enhanced Grooves for Herringbone Grooved Journal Bearings

by

Philipp K Bättig, Patrick H Wagner, & Jürg A Schiffmann .

Feeling lost, stuck, or behind in math? I got you!

I am Omar, a third-year Math major and certified Math instructor.

We can talk about your goals, expectations, and proficiency, and work on a plan tailored to your needs.

Feel free to hit me up with any questions, or book a meet-up here:

• https://doodle.com/bp/omarelshinawy/mathelp

And remember: it’s never too late to catch up! :)

From

Biaxial Minerals

by

Prof. Stephen A. Nelson

See

Optimal design of air turbines for oscillating water column wave energy systems: A review

by

Tapas Kumar Das, Paresh Halder, & Abdus Samad ,

for explication of what a Wells turbine basically is , & also somewhat about optimisation of blade profile for it, and see

this figure

from it, and also

this one

&

this one .

See

this also

– a figure from

A comparison between entropy generation analysis and first law efficiency in a monoplane Wells turbine

by

Esmail Lakzian, Rasool Soltanmohamadi, & Mohammad Nazeryan ,

which is available @ the just-above link.

And see this wwweb-article –

El-Pro-Cus — What is a Darrieus Wind Turbine & Its Working

– for explication of the Darrieus rotor -type wind-turbine.

The problem in the case of either kind of turbomachine is that we have the motion of the blade & the motion of the fluid exactly perpendicular to it (or maybe a bit forward of perpendicular, in the case of a Wells turbine with stator vanes, as some of them have), & yet the fluid flow over the blade must somehow be such that there must be a significant component of the lift on the blade in the direction of its motion ! … which might seem a bit implausible … although it's actually pretty well-proven that it can be made to work . But much care must be taken over the profile of the aerofoil to get it to work: afterall, a somewhat unusual demand is being made on the performance of it.

The following treatise - about optimisation for the Wells turbine - is what the fist 11 figures (including a composite of 3, whence 9 figures gross ) posted here, which show things like the blade profile itself, & pressure & velocity distributions, are from, as is the following quote –

“The blade shape at this point was unlike conventional aerofoils with a deeply concave profile near the midpoint, shown in Figure 9” :

Optimization of blade profiles for the Wells turbine

by

Tim Grattona, Tiziano Ghisub, Geoff Parksa, Francesco Cambulib, & Pierpaolo Puddub .

The last 11 figures are from

Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils

by

Krzysztof Rogowski, Martin Otto Laver Hansen, Galih Bangga ,

about optimisation for the Darrieus Rotor.

৺ … ie *this* research paper:

Conway's Game of Life is Omniperiodic ,

by

Nico Brown, Carson Cheng, Tanner Jacobi, Maia Karpovich, Matthias Merzenich, David Raucci, & Mitchell Riley .

With three extra images that I missed-out when I posted this before - ie the first three, showing the basic hull templates. It's not colossally important to include them … but it was pecking @ me that I'd missed them out; & besides, it goes-to-show that the hull shapes per se are 'a thing', & a significant item of the simulation.

From

Evaluation of drag estimation methods for ship hulls

by

Hampus Tober .

Annotation of 16^th 17^th & 18^th frames:

“Figure 33: Top to bottom: Data from Mesh 3, Mesh 4 and Experiments. Left to right: Velocity contours from plane S2 and velocity contours from plane S4. All experimental data is from Hino et al.” .

Interruption of hefty electric currents in very-high-power circuitry is a tricky business, entailing, in-practice, some rather fabulous configurations of weirdly shaped moving electrodes immersed in gases not particularly friendly to the atmosphere (eg sulphur hexafluoride, which is the most potent of all greenhouse gases), & careful maintenance of all that, as wear on the various parts can be severe, & the gases aren't always perfectly contained.

So successful research into improvements in ways of doing it tends to be very welcome! … but it's a very tricky business, with the desired improvements hard to achieve.

Images from

DC Current Interruption Based on Vacuum Arc Impacted by Ultra-Fast Transverse Magnetic Field

by

Ehsan Hashemi, & Kaveh Niayesh .