scholarly journals The polarity of thunderclouds

1932 ◽  
Vol 138 (834) ◽  
pp. 205-229 ◽  
Keyword(s):  
South Africa ◽  
Negative Charge ◽  
Upper Atmosphere ◽  
Positive Polarity ◽  
The Earth ◽  
Positively Charged

The mechanism of the maintenance of the negative charge upon the surface of the earth has long been sought. C. T. R. Wilson has made the suggestion that the activity of thunderstorms of positive polarity—positively charged above and negatively charged below—will serve to separate positive and negative charges, by carrying negative charges to the earth and positive charges to the upper atmosphere. Experiments carried out by him during and subse­quent to 1916 indicated the presence of clouds predominantly of positive polarity, and similar experiments carried out by Schonland and Craib, in South Africa, gave similar conclusions. Appleton, Watt and Herd made observations on the form of atmospherics, and came to the conclusion that the thunderclouds which were the seat of the disturbances producing atmospherics were of positive polarity.

scholarly journals The electric fields of South African thunderstorms

1927 ◽  
Vol 114 (767) ◽  
pp. 229-243 ◽  
Keyword(s):  
South African ◽  
Electric Fields ◽  
Negative Charge ◽  
Reverse Current ◽  
Positive Polarity ◽  
The Earth ◽  
Fine Weather ◽  
Lightning Discharges ◽  
Positively Charged ◽  
Made In

The quantitative study of the electrical changes taking place in thunderstorms was initiated and has been developed by Prof. C. T. R. Wilson in two important papers. Measurements of the electric fields due to charged clouds and of the field changes associated with lightning discharges have led him to put forward certain views according to which the thunderstorm is an important factor in the production and maintenance of several electro-meteorological phenomena with which it has not previously been considered connected. Chief amongst these is the negative charge on the surface of the earth, for the replenishment of which the views of Wilson require a certain preponderance of thunderclouds of positive polarity, i.e ., positively charged above and negatively charged below, over clouds of negative polarity, the ionisation currents between the bases of the clouds of the former type and the ground serving to maintain the earth’s charge at a steady value in spite of the reverse current flowing in regions of fine weather. It is necessary, in order to test this theory, that observations be made in different parts of the world to examine whether the required preponderance of clouds of positive polarity exist. For this purpose South Africa, which contributes largely to the world’s supply of thunderstorms, is very suitable.

scholarly journals Explicitly Simulated Electrification and Lightning within a Tropical Cyclone Based on the Environment of Hurricane Isaac (2012)

2015 ◽  
Vol 72 (11) ◽  
pp. 4167-4193 ◽  
Author(s):  
Alexandre O. Fierro ◽  
Edward R. Mansell ◽  
Conrad L. Ziegler ◽  
Donald R. MacGorman
Keyword(s):  
Tropical Cyclone ◽  
Negative Charge ◽  
Lightning Activity ◽  
Ice Crystals ◽  
Weather Research And Forecasting ◽  
The Earth ◽  
Ice Water Path ◽  
Total Lightning ◽  
Ice Water ◽  
Positively Charged

Abstract This work analyzes a high-resolution 350-m simulation of the electrification processes within a hurricane in conjunction with available total lightning observations to augment the general understanding of some of the key cloud-scale electrification processes within these systems. The general environment and trends of Hurricane Isaac (2012), whose lightning activity was observed by the Earth Networks Total Lightning Network, were utilized to produce a reasonable tropical cyclone simulation. The numerical model in this work employs explicit electrification and lightning parameterizations within the Weather Research and Forecasting Model. Overall, simulated storm-total flash origin density rates remain comparable to the observations. Because simulated reflectivities were larger and echo tops were higher in the eyewall than observed, the model consistently overestimated lightning rates there. The gross vertical charge structure in the eyewall resembled a normal tripole or a positive dipole, depending on the location. The negative charge at middle levels and positive at upper levels arose primarily from noninductive charging between graupel and ice crystals/snow. As some graupel melted into rain, the main midlevel negative charge region extended down to the surface in some places. The large volume of positively charged snow aloft caused a radially extensive negative screening layer to form on the lighter ice crystals above it. Akin to continental storms and tropical convection, lightning activity in the eyewall was well correlated with the ice water path (r > 0.7) followed by the graupel + hail path (r ≈ 0.7) and composite reflectivity at temperatures less than −10°C and the snow + ice path (r ≈ 0.5). Relative maxima in updraft volume, graupel volume, and total lightning rates in the eyewall all were coincident with the end of an intensification phase.

scholarly journals Calibration of Radiocarbon Dates for the Late Pleistocene Using U/Th Dates on Stalagmites

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-32 ◽  
Author(s):  
John C. Vogel ◽  
Joel Kronfeld
Keyword(s):  
South Africa ◽  
Magnetic Dipole ◽  
Satisfactory Agreement ◽  
Late Pleistocene ◽  
Calibration Curve ◽  
Dipole Field ◽  
Radiocarbon Dates ◽  
The Past ◽  
The Earth ◽  
Magnetic Dipole Field

Twenty paired 14C and U/Th dates covering most of the past 50,000 yr have been obtained on a stalagmite from the Cango Caves in South Africa as well as some additional age-pairs on two stalagmites from Tasmania that partially fill a gap between 7 ka and 17 ka ago. After allowance is made for the initial apparent 14C ages, the age-pairs between 7 ka and 20 ka show satisfactory agreement with the coral data of Bard et al. (1990, 1993). The results for the Cango stalagmite between 25 ka and 50 ka show the 14C dates to be substantially younger than the U/Th dates except at 49 ka and 29 ka, where near correspondence occurs. The discrepancies may be explained by variations in 14C production caused by changes in the magnetic dipole field of the Earth. A tentative calibration curve for this period is offered.

First Principles Investigation of the Stability and the Chemical Behavior of Hydrogen in ThCoH4

2011 ◽  
Vol 66 (3) ◽  
pp. 269-274
Author(s):  
Samir F. Matar
Keyword(s):  
Negative Charge ◽  
Geometry Optimization ◽  
Full Geometry Optimization ◽  
Intermetallic Matrix ◽  
Charge Analysis ◽  
The Stability ◽  
The One ◽  
Site Selective ◽  
Bader Charge Analysis ◽  
Positively Charged

We address the changes in the electronic structure brought by the insertion of hydrogen into ThCo leading to the experimentally observed ThCoH4. Full geometry optimization positions the hydrogen in three sites stabilized in the expanded intermetallic matrix. From a Bader charge analysis, hydrogen is found to be in a narrow iono-covalent (~−0.6) to covalent (~−0.3) bonding which should enable site-selective desorption. The overall chemical picture shows a positively charged Thδ+ with the negative charge redistributed over a complex anion {CoH4}δ− with δ~1.8. Nevertheless this charge transfer remains far from the one in the more ionic hydridocobaltate anion CoH54− in Mg2CoH5, due to the largely electropositive character of Mg.

The solar energetic flux and its impact on the Earth upper atmosphere

2002 ◽  
Vol 12 (10) ◽  
pp. 253-280 ◽  
Author(s):  
J. Lilensten ◽  
M. Kretzschmar
Keyword(s):  
Upper Atmosphere ◽  
The Earth

Aerosol in the Upper Atmosphere of the Earth Study

2021 ◽  
Author(s):  
Petro Nevodovskyi ◽  
Anatoliy Vid'machenko ◽  
Orest Ivakhiv ◽  
Olexsandr Zbrutskyi ◽  
Mykhaylo Geraimchuk ◽  
...  
Keyword(s):  
Upper Atmosphere ◽  
The Earth

A rare free silica-bearing micrometeorite

2021 ◽  
Author(s):  
Dafilgo Fernandes
Keyword(s):  
Mineral Assemblage ◽  
Frictional Heating ◽  
Upper Atmosphere ◽  
Carbonaceous Chondrites ◽  
Mineral Phase ◽  
Unique Type ◽  
Free Silica ◽  
System A ◽  
The Earth ◽  
Cosmic Spherules

<p>Extraterrestrial dust that reaches the Earth’s surface has shown to represent the diverse types of samples from different precursors, namely, asteroid complexes and cometary bodies from the solar system. A substantial amount of this dust that strikes the upper atmosphere is believed to have been lost due to frictional heating with air molecules. Cosmic spherules that are melted particles are some of the widely recognized micrometeorites that survived this catastrophic entry process; however, their primordial characteristics are altered from their precursors making it difficult to identify the precursors. An individual peculiar spherule MS-I35-P204 recovered from the Antarctica blue ice has been identified. The spherule has been segregated using magnetic separation method, mounted in epoxy, and examined using SEM, subsequently analysed under electron microprobe. It is surrounded by a thin magnetite rim, and also holds a single kamacite bead that protrudes out at its top. The interior mineralogy mostly constitutes of a bulk pyroxene normative glass (MnO>2wt%) with several vesicles. The rare mineral phase is a skeletal aggregate of free silica, bearing Fe nuggets embedded in a glass. An isolated narrow lath of forsterite appears to be chondritic and is observed as relict grain that is associated with an anomalous low Ca pyroxene (MnO ~1.3 wt%, FeO~13 wt%). Earlier, free silica has been reported in some chondritic meteorites particularly the Enstatite and Ordinary group, and also in some carbonaceous chondrites such as CM, CR, CH, and K. It profoundly forms a pod that encloses the ferromagnesian silicate in silica-bearing chondrules. The unusual mineral assemblage seen in this spherule thereby appears to constrain probably the unique type of its contributor which need to be studied.</p>

THE EFFECT OF PROCOAGULANT PHOSPHOLIPID VESICLES WITH NET POSITIVE CHARGE ON THE ACTIVITY OF PROTHROMBINASE

1987 ◽  
Author(s):  
J Rosing ◽  
H Speijer ◽  
J W P Govers-Riemslag ◽  
R F A Zwaal
Keyword(s):  
Vitamin K ◽  
Negative Charge ◽  
Positive Charge ◽  
Coagulation Factor ◽  
Phospholipid Vesicles ◽  
Electrostatic Model ◽  
Acidic Phospholipid ◽  
Positively Charged ◽  
Net Positive Charge ◽  
Prothrombin Activation

It is generally thought that procoagulant phospholipid surfaces that promote the activation of vitamin K-dependent coagulation factors should have a net negative charge in order to promote calcium-dependent binding of the enzymes (FVIIa, FIXa and FXa) and substrates (prothrombin and FX) of the coagulation factor-activating complexes. Two models have been proposed to explain calcium-mediated association of vitamin K-dependent proteins with phospholipid: a) an electrostatic model, in which a positively-charged protein-calcium complex is attracted by a negatively-charged phospholipid surface and b) a chelation model in which a coordination complex is formed between calcium ions, γ-carboxyglutamic acids of the proteins and negatively-charged membrane phospholipids. To study the effect of the electrostatic potential of phospholipid vesicles on their activity in the pro-thrombinase complex the net charge of vesicles was varied by introduction of varying amounts of positively-charged stearylamine in the membrane surface. Introduction of 0-15 mole% stearylamine in phospholipid vesicles that contained 5 mole% phosphatidylseri-ne (PS) hardly affected their activity in prothrombin activation. Electrophoretic analysis showed that vesicles with > 5 mole% stearylamine had a net positive charge. The procoagulant activity of vesicles that contained phosphatidic acid, phosphatidylglyce-rol, phosphatidylinositol or phosphatidyl-glactate (PLac) as acidic phospholipid was much more effected by incorporation of stearylamine. Amounts of stearylamine that compensated the negative charge of acidic phospholipid caused considerable inhibition of the activity of the latter vesicles in prothrombin activation. The comparison of vesicles containing PS and PLac as acidic phospholipid is of special interest. PS and PLac only differ by the presence of NH+ 3-group in the serine moiety of PS. Thus, in spite of the fact that vesicles with PLac are more negatively charged than vesicles with PS, they are less procoagulant. Our results show that a) although procoagulant membranes have to contain acidic phospholipids there is no requirement for a net negative charge, b) the amino group of phosphatidylserine has an important function in the interaction of procoagulant membranes with vitamin K-dependent proteins and c) the chelation model can satisfactorily explain calcium-mediated lipid-protein association.

scholarly journals The Position of Solid Carbon Dioxide in the Triboelectric Series

2019 ◽  
Vol 72 (8) ◽  
pp. 633 ◽  
Author(s):  
Jinyang Zhang ◽  
Simone Ciampi
Keyword(s):  
Carbon Dioxide ◽  
Negative Charge ◽  
Plastic Material ◽  
Indirect Evidence ◽  
Liquid Carbon ◽  
Solid Carbon Dioxide ◽  
Dry Ice ◽  
First Time ◽  
Charge Sign ◽  
Positively Charged

The process of releasing liquid carbon dioxide from a fire extinguisher is accompanied by a strong static charging of the plastic material making up the extinguisher discharge horn. Firefighters often report an electric shock when operating CO2 extinguishers, but the origin of this electrostatic hazard is largely unknown. Here, we begin to investigate this phenomenon, and test the hypothesis of plastic samples being tribocharged on contact with rapidly flowing solid CO2. Using Faraday pail measurements, we show that non-conductive polymers gain a net static charge when brought in and out of contact with dry ice (solid CO2). These measurements of charge sign and magnitude give indirect evidence helping to place solid CO2 for the first time on the triboelectric series. Polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), and polyvinyl chloride (PVC) samples acquire a negative charge when rubbed against dry ice, whereas poly(methyl methacrylate) (PMMA), glass, and nylon surfaces become positively charged. Therefore, we suggest the position of dry ice in the triboelectric series to be close to that of materials with stable cations and unstable anions, possibly locating it between PMMA and PVC.

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