Repulsion and attraction caused by radiometric forces

2012 ◽  
Author(s):  
Austin Ventura ◽  
Andrew Ketsdever ◽  
Rebecca Webb ◽  
Alina Alexeenko ◽  
Natalia Gimelshein ◽  
...  
Keyword(s):  
Repulsion And Attraction ◽  
Radiometric Forces

3. Forms of matter

2019 ◽  
pp. 19-38
Author(s):  
Geoff Cottrell
Keyword(s):  
Thermal Motion ◽  
Chemical Bonds ◽  
Intermediate States ◽  
State Of Matter ◽  
Volume Forms ◽  
Repulsion And Attraction

Solids, liquids, and gases are the great states of matter; a solid has a shape and a volume, a liquid has a volume but no shape, and a gas has neither shape nor volume. ‘Forms of matter’ explains how these different states arise from a competition between opposites: thermal motion driving particles apart and the attractive forces between atoms pulling them together, repulsion and attraction. The ‘glue’ that holds electrons to atoms, brings atoms together to form molecules, and draws molecules together to make solids and liquids, is electricity. Chemical bonds, crystals, intermediate states, and plasma—the fourth state of matter—are discussed.

Localisation, Ghanaian Pentecostalism and the Stranger's Beauty in Botswana

Africa ◽  
2003 ◽  
Vol 73 (4) ◽  
pp. 560-583 ◽  
Author(s):  
Rijk van Dijk
Keyword(s):  
Identity Politics ◽  
Common Ground ◽  
Host Society ◽  
Current Position ◽  
Migrant Community ◽  
Pentecostal Churches ◽  
The One ◽  
The City ◽  
Repulsion And Attraction ◽  
The Way

AbstractThis contribution considers the current position of the Ghanaian migrant community in Botswana's capital, Gaborone, at a time of rising xenophobic sentiments and increasing ethnic tensions among the general public. The article examines anthropological understandings of such sentiments by placing them in the context of the study of nationalisms in processes of state formation in Africa and the way in which these ideologies reflect the position and recognition of minorities. In Botswana, identity politics indulge in a liberalist democratic rhetoric in which an undifferentiated citizenship is promoted by the state, concealing on the one hand inequalities between the various groups in the country, but on the other hand defending the exclusive interests of all ‘Batswana’ against foreign influence through the enactment of what has become known as a ‘localisation policy'. Like many other nationalities, Ghanaian expatriate labour has increasingly become the object of localisation policies. However in their case xenophobic sentiments have taken on unexpected dimensions. By focusing on the general public's fascination with Ghanaian fashion and styles of beautification, the numerous hair salons and clothing boutiques Ghanaians operate, in addition to the newly emerging Ghanaian-led Pentecostal churches in the city, the ambiguous but ubiquitous play of repulsion and attraction can be demonstrated in the way in which localisation is perceived and experienced by the migrant as well as by the dominant groups in society. The article concludes by placing entrepreneurialism at the nexus of where this play of attraction and repulsion creates a common ground of understanding between Ghanaians and their host society, despite the government's hardening localisation policies.

EFFECT OF TEMPERATURE ON INTRINSIC LOCALIZED MODES IN ANHARMONIC LATTICES

2000 ◽  
Vol 14 (27n28) ◽  
pp. 1001-1007 ◽  
Author(s):  
J. N. TEIXEIRA RABELO ◽  
E. S. CARDOSO ◽  
V. I. ZUBOV
Keyword(s):  
Linear Chain ◽  
Effect Of Temperature ◽  
Localized Modes ◽  
Jones Potential ◽  
Intrinsic Localized Modes ◽  
Lennard Jones ◽  
Self Consistent Field ◽  
Special Case ◽  
Repulsion And Attraction ◽  
Parity Mode

We study the effect of temperature on Intrinsic Localized Modes (ILM) in anharmonic lattices. An approach is proposed based on the Method of the Unsymmetrized Self-Consistent Field (USF). The special case of an odd-parity mode in an anharmonic linear chain with Mie–Lennard–Jones potential is investigated in more detail. We find that in the weak anharmonic approximation, an increasing of temperature does not change the pattern of the mode, leading to a very small decreasing of the displacement amplitudes and a decreasing of the mode frequency. The frequency of the mode increases with increasing of both the repulsion and attraction indexes. This effect is more sensitive to the repulsion index.

Origins of radiometric forces on a circular vane with a temperature gradient

2009 ◽  
Vol 634 ◽  
pp. 419 ◽  
Author(s):  
NATHANIEL SELDEN ◽  
CEDRICK NGALANDE ◽  
NATALIA GIMELSHEIN ◽  
SERGEY GIMELSHEIN ◽  
ANDREW KETSDEVER
Keyword(s):  
Temperature Gradient ◽  
Radiometric Forces

scholarly journals Orientation repulsion and attraction in alignment perception

2007 ◽  
Vol 47 (12) ◽  
pp. 1693-1704 ◽  
Author(s):  
Tzvetomir Tzvetanov ◽  
Andrea Wirmer ◽  
Kristian Folta
Keyword(s):  
Repulsion And Attraction

Effect of vane thickness on radiometric force

2013 ◽  
Vol 735 ◽  
pp. 684-704 ◽  
Author(s):  
Austin Ventura ◽  
Natalia Gimelshein ◽  
Sergey Gimelshein ◽  
Andrew Ketsdever
Keyword(s):  
Experimental Study ◽  
Pressure Difference ◽  
Shear Force ◽  
Vortex Flow ◽  
Lateral Side ◽  
Height Ratio ◽  
Flow Through ◽  
Cold Chamber ◽  
Different Thickness ◽  
Radiometric Forces

AbstractA numerical and experimental study of radiometric forces on vanes of different thickness is presented for the flow regime where the radiometric force is near its maximum. For single- and multi-vane geometries, it is shown that radiometric force decreases by only ∼10–15 % when the vane thickness-to-height ratio increases fourfold from 0.5 to 2. For a single-vane geometry, the shear force on the lateral side of the vane is attributed to a vortex flow generated by the interaction of cold chamber walls and heated walls of the vane. In that case, it always acts to reduce the total radiometric force governed by the pressure difference between the hot and the cold sides of the vane. For a multi-vane geometry, represented by a perforated vane, the shear force becomes positive for larger thickness-to-height ratios and lower pressures, primarily due to strong vane-driven transpiration flow through the gaps.

scholarly journals Axon Guidance: Repulsion and Attraction in Roundabout Ways

2010 ◽  
Vol 20 (9) ◽  
pp. R400-R402 ◽  
Author(s):  
Kartik S. Pappu ◽  
S. Lawrence Zipursky
Keyword(s):  
Axon Guidance ◽  
Repulsion And Attraction
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