Splashing of water drops on solid and wetted surfaces: hydrodynamics and charge separation

1971 ◽  
Vol 269 (1200) ◽  
pp. 555-585 ◽  
Keyword(s):  
Electric Field ◽  
Charge Separation ◽  
Applied Electric Field ◽  
Positive Charge ◽  
Ammonium Hydroxide ◽  
Impact Speed ◽  
Space Charges ◽  
Water Drops ◽  
The Impact

The charges separated by splashes on solid and wetted surfaces are shown to be carried on the liquid fragments ejected from the crown. Experimental observations on the nature of these splashes are presented and mechanisms for the formation and break-up of the crown are proposed. The surface on which a splash occurs is generally left with a positive charge, the magnitude of which decreases with increasing concentration of solute in the drop. This is explained by the disruption of the electrical double layer. When drops containing ammonium hydroxide in excess of 2.5 x 10-5 mol 1_1 splash on ice at — 1 °C the ice receives a positive charge. In this case, freezing potentials appear to play a role in the charging. In an applied electric field the charges separated by splashing increase as the field is increased, in agreement with an induction mechanism of charging. Also, in an applied electric field, the charges initially increase as the impact speed is increased but beyond a certain impact speed the charges decrease. This is explained in terms of the relative magnitudes of the time of contact of the ejected liquid fragments with the crown and the relaxation time of charge carriers in the liquid. The role of charge separation due to splashing in thunderstorm electrification and in the build-up of space charges during rainfall is discussed.

scholarly journals The Ionization of Liquid Argon by a-Particles

1958 ◽  
Vol 11 (2) ◽  
pp. 158 ◽  
Author(s):  
FD Stacey
Keyword(s):  
Electric Field ◽  
Charge Separation ◽  
Applied Electric Field ◽  
Positive Charge ◽  
Liquid Argon ◽  
Energetic Electrons

Calculations suggest that in liquid argon the column of ionization produced by :an a-particle consists of a core of positive charge 0�6?1 �5�10?5 cm in diameter concentric with a larger cloud of electrons extending to a diameter of 40�10?5 cm. This leads to a new description of charge separation in an applied electric field, in which the positive and negative charges are drawn apart slightly (polarized) and the more energetic electrons Bscape from the edge of the column.

scholarly journals A deep insight into the ion foreshock with the help of test particle two-dimensional simulations

2020 ◽  
Vol 38 (6) ◽  
pp. 1217-1235
Author(s):  
Philippe Savoini ◽  
Bertrand Lembège
Keyword(s):  
Electric Field ◽  
Shock Front ◽  
Test Particle ◽  
Field Component ◽  
Upstream Region ◽  
Mirror Reflection ◽  
Two Dimensional ◽  
Shock Profiles ◽  
The Impact

Abstract. Two-dimensional (2D) test particle simulations based on shock profiles issued from 2D full particle-in-cell (PIC) simulations are used in order to analyze the formation processes of ions back streaming within the upstream region after interacting with a quasi-perpendicular curved shock front. Two different types of simulations have been performed based on (i) a fully consistent expansion (FCE) model, which includes all self-consistent shock profiles at different times, and (ii) a homothetic expansion (HE) model in which shock profiles are fixed at certain times and artificially expanded in space. The comparison of both configurations allows one to analyze the impact of the front nonstationarity on the back-streaming population. Moreover, the role of the space charge electric field El is analyzed by either including or canceling the El component in the simulations. A detailed comparison of these last two different configurations allows one to show that this El component plays a key role in the ion reflection process within the whole quasi-perpendicular propagation range. Simulations provide evidence that the different field-aligned beam (FAB) and gyro-phase bunched (GPB) populations observed in situ are essentially formed by a Et×B drift in the velocity space involving the convective electric field Et. Simultaneously, the study emphasizes (i) the essential action of the magnetic field component on the GPB population (i.e., mirror reflection) and (ii) the leading role of the convective field Et in the FAB energy gain. In addition, the electrostatic field component El is essential for reflecting ions at high θBn angles and, in particular, at the edge of the ion foreshock around 70∘. Moreover, the HE model shows that the rate BI% of back-streaming ions is strongly dependent on the shock front profile, which varies because of the shock front nonstationarity. In particular, reflected ions appear to escape periodically from the shock front as bursts with an occurrence time period associated to the self-reformation of the shock front.

scholarly journals Measurement of Dust Electric Charges by the Ulysses and Galileo Dust Detectors

1996 ◽  
Vol 150 ◽  
pp. 481-484 ◽  
Author(s):  
J. Svestka ◽  
S. Auer ◽  
M. Baguhl ◽  
E. Grün
Keyword(s):  
Electric Field ◽  
Dust Particle ◽  
Time Of Flight ◽  
Opposite Polarity ◽  
Dust Particles ◽  
Impact Speed ◽  
The Impact

The Galileo and Ulysses dust detectors can detect electric charges of dust particles. Dust particles entering the sensor (see, e.g., Grün et al. 1992) may be detected by the charge Qp that they induce to the charge grid. All suitably massive dust particles - charged or uncharged - are then detected by the cloud of ions and electrons they produce during the impact on the hemispherical target after the time of flight between the charge grid and the target. After separation in the electric field, ions and electrons are collected by separate electrodes and produce two pulses of opposite polarity. From the two pulse heights and the rise times, the mass and impact speed of the dust particle are derived.

scholarly journals Role of hydrogen bond alternation and charge transfer states in photoactivation of the Orange Carotenoid Protein

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Igor A. Yaroshevich ◽  
Eugene G. Maksimov ◽  
Nikolai N. Sluchanko ◽  
Dmitry V. Zlenko ◽  
Alexey V. Stepanov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Electric Field ◽  
Quantum Chemical ◽  
Time Resolved ◽  
Bond Alternation ◽  
Orange Carotenoid Protein ◽  
The Impact

AbstractHere, we propose a possible photoactivation mechanism of a 35-kDa blue light-triggered photoreceptor, the Orange Carotenoid Protein (OCP), suggesting that the reaction involves the transient formation of a protonated ketocarotenoid (oxocarbenium cation) state. Taking advantage of engineering an OCP variant carrying the Y201W mutation, which shows superior spectroscopic and structural properties, it is shown that the presence of Trp201 augments the impact of one critical H-bond between the ketocarotenoid and the protein. This confers an unprecedented homogeneity of the dark-adapted OCP state and substantially increases the yield of the excited photoproduct S*, which is important for the productive photocycle to proceed. A 1.37 Å crystal structure of OCP Y201W combined with femtosecond time-resolved absorption spectroscopy, kinetic analysis, and deconvolution of the spectral intermediates, as well as extensive quantum chemical calculations incorporating the effect of the local electric field, highlighted the role of charge-transfer states during OCP photoconversion.

scholarly journals A deep insight into the Ion Foreshock with the help of Test-particles Two-dimensional simulations

2020 ◽  
Author(s):  
Philippe Savoini ◽  
Bertrand Lembege
Keyword(s):  
Electric Field ◽  
Shock Front ◽  
Field Component ◽  
Upstream Region ◽  
Two Dimensional ◽  
Test Particles ◽  
Shock Profiles ◽  
Expansion Model ◽  
The Impact

Abstract. Two dimensional test-particles simulations based on shock profiles issued from 2D full PIC simulations are used in order to analyze the formation processes of ions backstreaming within the upstream region after these interact with a quasi-perpendicular curved shock front. Two different types of simulations have been performed based on (i) a FCE (Full Consistent Expansion) model which includes all self-consistent shock profiles at different times, and (ii) a HE (Homothetic Expansion) model where shock profiles are fixed at certain times and artificially expanded in space. The comparison of both configurations allows to analyze the impact of the front non stationarity on the backstreaming population. Moreover, the role of the space charge electric field is analyzed by switching it in/off in the simulations. A detailled comparison of these two last different configurations allows to show that the electric field component plays a key role in the ion reflection process within the whole quasi-perpendicular propagation range. Simulations evidence that the different populations observed in-situ namely the FAB (Field-Aligned Beam) and GBP (Gyro-Phase Bunch) populations are essentially formed by a E→t × B→ drift involving the convective electric field E→t. Simultaneously, the study emphasizes the leading role of the electrostatic (longitudinal) field E→l built up within the shock front in the acceleration process in addition to the magnetic mirror reflection (Fast Fermi). This electrostatic field component appears as essential to form backstreaming ions at high θBn angles and in particular at the edge of the ion foreshock around 70°. Moreover, the HE model shows that the rate BI% of reflected ions is strongly dependent on the shock front profile which varies because of the shock front non stationarity. In particular, reflected ions appear to escape periodically from the shock front as bursts  with an occurrence time period associated to the self-reformation of the shock front.

The role of an applied electric field in protein crystallization at low temperature

2019 ◽  
Vol 58 (11) ◽  
pp. 110903
Author(s):  
Makoto Ogata ◽  
Daichi Aoki ◽  
Moeka Suzuki ◽  
Daisuke Tanaka ◽  
Takashi Wakamatsu
Keyword(s):  
Low Temperature ◽  
Electric Field ◽  
Applied Electric Field ◽  
Protein Crystallization

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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