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Archive for the ‘PHYSICS’ Category

Modeling Transport of SARS-CoV-2 Inside a Charlotte Area Transit System (CATS) Bus

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Gregory McGowan, Jeffrey Feaster, Andy Jones, Lucas Agricola, Matthew Goodson, William Timms, Mesbah Uddin
We present in this paper a model of the transport of human respiratory particles on a Charlotte Area Transit System (CATS) bus to examine the efficacy of interventions to limit exposure to SARS-CoV-2, the virus that causes COVID-19. The methods discussed here utilize a commercial Navier-Stokes flow solver, RavenCFD, run using a massively parallel supercomputer to model the flow of air through the bus under varying conditions, such as windows being open or the HVAC flow settings. Lagrangian particles are injected into the RavenCFD predicted flow fields to simulate the respiratory droplets from speaking, coughing, or sneezing. These particles are then traced over time and space until they interact with a surface or are removed via the HVAC system. Finally, a volumetric Viral Mean Exposure Time (VMET) is computed to quantify the risk of exposure to the SARS-CoV-2 under various environmental and occupancy scenarios. Comparing the VMET under varying conditions should help identify viable methods to reduce the risk of viral exposure of CATS bus passengers during the COVID-19 pandemic.

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Written by physicsgg

August 4, 2021 at 7:40 am

Posted in PHYSICS

Applying physics to mathematics

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by Tadashi Tokieda

abstract : Humans tend to be better at physics than at mathematics. When an apple falls from a tree, there are more people who can catch it—we know physically how the apple moves—than people who can compute its trajectory from a differential equation. Applying physical ideas to discover and establish mathematical results is therefore natural, even if it has seldom been tried in the history of science. (The exceptions include Archimedes, some old Russian sources, a recent book by Mark Levi, as well as my articles and lectures.) This TMC Distinguished Lecture presents a diversity of examples, and tries to make them easy for imaginative beginners and difficult for seasoned researchers.

Written by physicsgg

July 8, 2021 at 7:54 pm

Posted in MATHEMATICS, PHYSICS

Chirality Through Classical Physics

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Chris L. Lin
Chirality, or handedness, is a topic that is common in biology and chemistry, yet is rarely discussed in physics courses. We provide a way of introducing the topic in classical physics, and demonstrate the merits of its inclusion – such as a simple way to visually introduce the concept of symmetries in physical law – along with giving some simple proofs using only basic matrix operations, thereby avoiding the full formalism of the three-dimensional point group.
Read also https://arxiv.org/pdf/2004.08236.pdf

Click to access 2004.08236.pdf

Written by physicsgg

April 20, 2020 at 8:03 am

Posted in PHYSICS

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Memory and entropy

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Carlo Rovelli
I study the physical nature of traces (or memories). Surprisingly, (i) systems separation with (ii) temperature differences and (iii) long thermalization times, are sufficient conditions to produce macroscopic traces. Traces of the past are ubiquitous because these conditions are largely satisfied in our universe. I quantify these thermodynamical conditions for memory and derive an expression for the maximum amount of information stored in such memories, as a function of the relevant thermodynamical parameters. This mechanism transforms low entropy into available information.

Read more at https://arxiv.org/pdf/2003.06687.pdf

Written by physicsgg

March 17, 2020 at 7:51 am

10 amazing science experiments

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Written by physicsgg

March 2, 2019 at 9:35 am

Posted in PHYSICS

Graphic Talk about the Universe: Clifford V. Johnson

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In his public lecture webcast at Perimeter on February 7, Clifford V. Johnson discussed the process of turning complex scientific topics into compelling visual narratives.

Written by physicsgg

February 12, 2019 at 12:49 pm

Posted in PHYSICS

Effects of exoplanetary gravity on human locomotor ability

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Nikola Poljak, Dora Klindzic, Mateo Kruljac
At some point in the future, if mankind hopes to settle planets outside the Solar System, it will be crucial to determine the range of planetary conditions under which human beings could survive and function. In this article, we apply physical considerations to future exoplanetary biology to determine the limitations which gravity imposes on several systems governing the human body. Initially, we examine the ultimate limits at which the human skeleton breaks and muscles become unable to lift the body from the ground. We also produce a new model for the energetic expenditure of walking, by modelling the leg as an inverted pendulum. Both approaches conclude that, with rigorous training, humans could perform normal locomotion at gravity no higher than 4 gEarth.
Read more at https://arxiv.org/pdf/1808.07417.pdf

Written by physicsgg

August 23, 2018 at 5:36 pm

Posted in BIOLOGY, PHYSICS

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Emmy Noether changed the face of physics

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Written by physicsgg

June 13, 2018 at 5:36 am

Posted in PHYSICS, Uncategorized

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