Chernobyl’s ruins grow restless, and entangling macroscopic objects

Science ◽  
2021 ◽  
Author(s):  
Sarah Crespi
Keyword(s):  
Macroscopic Objects

Quantum fluctuations have been shown to affect macroscopic objects

Nature ◽  
2020 ◽  
Vol 583 (7814) ◽  
pp. 31-32
Author(s):  
Valeria Sequino ◽  
Mateusz Bawaj
Keyword(s):  
Quantum Fluctuations ◽  
Macroscopic Objects

scholarly journals Classical sub-subleading soft photon and soft graviton theorems in four spacetime dimensions

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Biswajit Sahoo
Keyword(s):  
Fourier Transformation ◽  
Soft Photon ◽  
Scattering Process ◽  
Retarded Time ◽  
Long Wavelength ◽  
Macroscopic Objects ◽  
Loop Amplitudes

Abstract Classical soft photon and soft graviton theorems determine long wavelength electromagnetic and gravitational waveforms for a general classical scattering process in terms of the electric charges and asymptotic momenta of the ingoing and outgoing macroscopic objects. Performing Fourier transformation of the electromagnetic and gravitational waveforms in the frequency variable one finds electromagnetic and gravitational waveforms at late and early retarded time. Here extending the formalism developed in [1], we derive sub-subleading electromagnetic and gravitational waveforms which behave like u−2(ln u) at early and late retarded time u in four spacetime dimensions. We also have derived the sub-subleading soft photon theorem analyzing two loop amplitudes in scalar QED. Finally, we conjectured the structure of leading non-analytic contribution to (sub)n-leading classical soft photon and graviton theorems which behave like u−n(ln u)n−1 for early and late retarded time u.

How Physical Interactions Shape Bacterial Biofilms

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Berenike Maier
Keyword(s):  
Extracellular Matrix ◽  
Environmental Changes ◽  
Bacterial Biofilms ◽  
Annual Review ◽  
Publication Date ◽  
Extracellular Matrix Components ◽  
Macroscopic Objects ◽  
Physical Interactions ◽  
Repulsive Forces ◽  
Biofilm Structure

Biofilms are structured communities formed by a single or multiple microbial species. Within biofilms, bacteria are embedded into extracellular matrix, allowing them to build macroscopic objects. Biofilm structure can respond to environmental changes such as the presence of antibiotics or predators. By adjusting expression levels of surface and extracellular matrix components, bacteria tune cell-to-cell interactions. One major challenge in the field is the fact that these components are very diverse among different species. Deciphering how physical interactions within biofilms are affected by changes in gene expression is a promising approach to obtaining a more unified picture of how bacteria modulate biofilms. This review focuses on recent advances in characterizing attractive and repulsive forces between bacteria in correlation with biofilm structure, dynamics, and spreading. How bacteria control physical interactions to maximize their fitness is an emerging theme. Expected final online publication date for the Annual Review of Biophysics, Volume 50 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Loose Ends

2019 ◽  
pp. 217-238
Author(s):  
Neil E. Williams
Keyword(s):  
Laws Of Nature ◽  
Macroscopic Objects ◽  
Primary Focus

The aim of this final chapter is to tie up some of the loose ends in the powers metaphysic. The first part of the chapter discusses what a powers theorist might say about the laws of nature. A hybrid powers-based account of the laws is offered that combines fundamental lawlessness with a best-systems account. Attention then shifts to macroscopic objects. The primary focus of the book has been on the fundamental powers; here the focus turns to the dispositions of middle-sized dry goods and the question of macroscopic persistence. In considering the former, something of a proto-analysis of macroscopic dispositionality is offered. The chapter ends with a discussion of systematic metaphysics.

scholarly journals Snow saltation threshold measurements in a drifting-snow wind tunnel

2006 ◽  
Vol 52 (179) ◽  
pp. 585-596 ◽  
Author(s):  
Andrew Clifton ◽  
Jean-Daniel Rüedi ◽  
Michael Lehning
Keyword(s):  
Particle Size ◽  
Wind Tunnel ◽  
Friction Velocity ◽  
Field Measurements ◽  
Drifting Snow ◽  
Velocity Relationship ◽  
Roughness Lengths ◽  
Surface Particle ◽  
Macroscopic Objects ◽  
Natural Snow

AbstractWind tunnel measurements of snowdrift in a turbulent, logarithmic velocity boundary layer have been made in Davos, Switzerland, using natural snow. Regression analysis gives the drift threshold friction velocity (u*t), assuming an exponential drift profile and a simple drift to friction velocity relationship. Measurements over 15 snow covers show that u*t is influenced more by snow density and particle size than by ambient temperature and humidity, and varies from 0.27 to 0.69 ms–1. Schmidt’s threshold algorithm and a modified version used in SNOWPACK (a snow-cover model) agree well with observations if small bond sizes are assumed. Using particle hydraulic diameters, obtained from image processing, Bagnold’s threshold parameter is 0.18. Roughness lengths (z0) vary between snow covers but are constant until the start of drift. Threshold roughness lengths are proportional to . The influence of macroscopic objects on the roughness length is shown by the lower values measured over the smooth and flat snow surface of the wind tunnel (0.04 ≤ z0 ≤ 0.13 mm), compared to field measurements. Mean drifting-snow grain sizes for mainly new and partly decomposed snow are 100–175 μm, and independent of surface particle size.

scholarly journals Low-Frequency Magnetic Scanning Device and Algorithm for Determining the Magnetic and Non-Magnetic Fractions of Moving Metallurgical Raw Materials

2019 ◽  
Vol 9 (10) ◽  
pp. 2001
Author(s):  
Vladimir Kochemirovsky ◽  
Svetlanav Kochemirovskaia ◽  
Michael Malygin ◽  
Alexey Kuzmin ◽  
Maxim Novomlinsky ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Raw Materials ◽  
Low Frequency ◽  
Raw Material ◽  
Magnetic Characteristics ◽  
Magnetic Fraction ◽  
Measuring Device ◽  
Mathematical Algorithm ◽  
Macroscopic Objects

The development of an algorithm to automate the process of measuring the magnetic properties of macroscopic objects in motion is an important problem in various industries, especially in ferrous metallurgy and at factories where ferrous scrap is a strategic raw material. The parameter that requires work control is the hidden mass fraction of a non-magnetic substance that is present in the ferromagnetic raw material. The solution to this problem has no prototypes. In our work, a simple measuring device and a mathematical algorithm for calculating the mass fraction of the non-magnetic fraction in a strongly magnetic matrix were developed. The device is an inductance coil, in which the angle of the electromagnet losses is related to the mass of the magnetic material moving the coil. The magnitude of the instantaneous values of the lost angle integral was compared with the result of weighing the object on scales. This allowed us to calculate the proportion of the magnetic and non-magnetic fractions. The use of this prototype is herein illustrated. The experimental results of the determination of the magnetic-fractional composition depending on the mass of scrap metal and its bulk and the magnetic characteristics are presented.

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