scholarly journals Luminous vapours distilled from the arc, with applications to the study of spectum series and their origin.-I

1914 ◽  
Vol 90 (619) ◽  
pp. 364-372 ◽  
Keyword(s):  
Electric Field ◽  
Electric Discharge ◽  
Small Scale ◽  
Mercury Lamp ◽  
Long Distance ◽  
Electric Discharge In Gases

In a paper entitled "Duration of Luminosity of Electric Discharge in Gases and Vapours," reference was made to a known phenomenon shown by the mercury arc in vacuo : when mercury is allowed to distil away from a mercury lamp into a lateral tube sealed on to it, the rapidly moving vapour carries its luminosity for a long distance out of the electric field. It was shown how effects not essentially different might be obtained with mercury, and other metals also, using not the arc, but the leyden jar spark between poles of the metal; but this method, owing to the intermittence of the sparks and the small scale of the effects, is far less satisfactory than the use of the arc. At the time of writing the paper cited, I thought that it would be very difficult to extend the use of the arc to metals less volatile than mercury, but the problem has proved more tractable than was expected 2. Method of Experimenting-Apparatus used . The vessel in which the arc is confined will be called, for convenience, a lamp, though it is not used directly as a source of light.

scholarly journals Duration of luminosity of electric discharge in gases and vapours: further studies

1917 ◽  
Vol 94 (657) ◽  
pp. 88-99 ◽  
Keyword(s):  
Electric Field ◽  
Electric Current ◽  
External Force ◽  
Electric Discharge ◽  
Electrostatic Field ◽  
Transverse Electric ◽  
Arc Discharge ◽  
Transverse Electric Field ◽  
Low Pressures ◽  
Electric Discharge In Gases

In several previous papers, I have described experiments showing that the luminosity of the spark or arc discharge through gases and metallic vapours lasts for an appreciable length of time after the discharge has ceased to pass, and that the luminous vapour can be removed from the region where the electric current is passing, and still remain luminous, showing the same spectrum as before, though in certain cases some lines of this spectrum fade out sooner than others. The present paper is a continuation of these studies. 1. The Luminous Jet at Very Low Pressures. Effect of a Transverse Electric Field . The first experiments to be described were designed to observe the effects at very low gaseous pressures, and with small currents. The advantage of this is that the luminous particles in the jet are then comparatively free to move under the action of an external force, and their motion in an electrostatic field can be conveniently examined. Moreover, since the ions are few, they do not disturb the uniformity of the electric field applied for this purpose.

scholarly journals MMS Multipoint electric field observations of small-scale magnetic holes

2016 ◽  
Vol 43 (12) ◽  
pp. 5953-5959 ◽  
Author(s):  
Katherine A. Goodrich ◽  
Robert E. Ergun ◽  
Frederick D. Wilder ◽  
James Burch ◽  
Roy Torbert ◽  
...  
Keyword(s):  
Electric Field ◽  
Small Scale ◽  
Field Observations

scholarly journals What Determines the Parameters of a Propagating Streamer: A Comparison of Outputs of the Streamer Parameter Model and of Hydrodynamic Simulations

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1664
Author(s):  
Nikolai G. Lehtinen ◽  
Robert Marskar
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Electric Discharge ◽  
Propagation Velocity ◽  
The Novel ◽  
Hydrodynamic Simulation ◽  
Hydrodynamic Simulations ◽  
Important Stage ◽  
Streamer Discharges

Electric streamer discharges (streamers) in the air are a very important stage of lightning, taking place before formation of the leader discharge, and with which an electric discharge starts from conducting objects which enhance the background electric field, such as airplanes. Despite years of research, it is still not well understood what mechanism determines the values of a streamer’s parameters, such as its radius and propagation velocity. The novel Streamer Parameter Model (SPM) was made to explain this mechanism, and to provide a way to efficiently calculate streamer parameters. Previously, we demonstrated that SPM results compared well with a limited set of experimental data. In this article, we compare SPM predictions to the published hydrodynamic simulation (HDS) results.

scholarly journals Is a spatial investigation possible without long-distance refit/conjoin? Application to the MIS 11 lithic assemblage of levels E and J from La Cansaladeta site (Tarragona, Spain)

2021 ◽  
Vol 13 (9) ◽  
Author(s):  
Görkem Cenk Yeşilova ◽  
Andreu Ollé ◽  
Josep Maria Vergès
Keyword(s):  
Spatial Patterns ◽  
Spatial Information ◽  
Small Dimension ◽  
Middle Pleistocene ◽  
Small Scale ◽  
Spatial Pattern Analysis ◽  
Long Distance ◽  
Great Opportunity ◽  
Density Mapping ◽  
Study Materials

AbstractIn this manuscript, we present the first systematic refitting results of the small-scale Middle Pleistocene (MIS11) rock shelter site of La Cansaladeta. The lithic materials that have been recovered from the archaeological levels E and J were the main study materials. These levels were investigated regarding spatial pattern analysis and analyzed with auxiliary methods such as quantitative density mapping demonstration and technological analysis of the lithic clusters. Thus, the spatial patterns of the two levels were compared and discussed, in terms of connections, clusters, and movement of the lithic elements. Undoubtedly, the well preservation of the archaeological levels offered a great opportunity for the interpretation of the spatial patterns in a high-resolution perspective. La Cansaladeta has not been paid attention adequately so far may be due to the small dimension of the excavation surface or to the scarcity of faunal record. Our results show that small-scale sites without long-distance refit/conjoin connections can provide significant spatial information. Indeed, if the sites have very well-preserved archaeological levels, the absence of long connections can be supported by the auxiliary methods.

Free Vibration Response of FG Porous Sandwich Micro-Beam with Flexoelectric Face-Sheets Resting on Modified Silica Aerogel Foundation

2019 ◽  
Vol 11 (09) ◽  
pp. 1950087 ◽  
Author(s):  
Ali Ghorbanpour Arani ◽  
Hassan Baba Akbar Zarei ◽  
Pouya Pourmousa
Keyword(s):  
Free Vibration ◽  
Electric Field ◽  
External Electric Field ◽  
Silica Aerogel ◽  
Free Vibration Analysis ◽  
Strain Gradient Theory ◽  
Small Scale ◽  
Gradient Theory ◽  
Dimensionless Frequency ◽  
Modified Silica

The free vibration analysis of sandwich micro-beam (SMB) which is subjected to electrical field is investigated by adopting the Euler–Bernoulli beam theory (EBBT) and modified strain gradient theory (MSGT). SMB is made of three layers, including a functionally graded (FG) porous core and two flexoelectric face-sheets. The porosities are assumed to be distributed over the beam thickness based on the two distribution functions. Also, due to the electric properties of flexoelectric materials, face-sheets of SMB are subjected to the external electric field. The modified Silica Aerogel foundation model is employed to consider the effects of elastic foundation on SMB. The size-dependent governing equations of motion are derived using Hamilton’s principle and solved by Navier’s solution method for a case of simply supported SMB. The effects of various parameters, such as length to thickness ratio, porosity index, flexoelectric loadings (the load applied to the flexoelectric face-sheets caused by external electric field), small scale parameter and foundation parameters on dimensionless frequency of SMB, are assessed. The results of this work can be used for optimum design and control of micro-electro-mechanical devices.

scholarly journals Electrostatic forces alter particle size distributions in atmospheric dust

2020 ◽  
Vol 20 (5) ◽  
pp. 3181-3190 ◽  
Author(s):  
Joseph R. Toth III ◽  
Siddharth Rajupet ◽  
Henry Squire ◽  
Blaire Volbers ◽  
Jùn Zhou ◽  
...  
Keyword(s):  
Electric Field ◽  
Size Distribution ◽  
Long Range ◽  
Electric Fields ◽  
Electrostatic Force ◽  
Small Scale ◽  
Size Distributions ◽  
Electrostatic Forces ◽  
Atmospheric Dust ◽  
Airborne Dust

Abstract. Large amounts of dust are lofted into the atmosphere from arid regions of the world before being transported up to thousands of kilometers. This atmospheric dust interacts with solar radiation and causes changes in the climate, with larger-sized particles having a heating effect, and smaller-sized particles having a cooling effect. Previous studies on the long-range transport of dust have found larger particles than expected, without a model to explain their transport. Here, we investigate the effect of electric fields on lofted airborne dust by blowing sand through a vertically oriented electric field, and characterizing the size distribution as a function of height. We also model this system, considering the gravitational, drag, and electrostatic forces on particles, to understand the effects of the electric field. Our results indicate that electric fields keep particles suspended at higher elevations and enrich the concentration of larger particles at higher elevations. We extend our model from the small-scale system to long-range atmospheric dust transport to develop insights into the effects of electric fields on size distributions of lofted dust in the atmosphere. We show that the presence of electric fields and the resulting electrostatic force on charged particles can help explain the transport of unexpectedly large particles and cause the size distribution to become more uniform as a function of elevation. Thus, our experimental and modeling results indicate that electrostatic forces may in some cases be relevant regarding the effect of atmospheric dust on the climate.

scholarly journals ‘Disperse abroad in the land’: the role of wildlife in the dissemination of antimicrobial resistance

2016 ◽  
Vol 12 (8) ◽  
pp. 20160137 ◽  
Author(s):  
Kathryn E. Arnold ◽  
Nicola J. Williams ◽  
Malcolm Bennett
Keyword(s):  
Antimicrobial Resistance ◽  
Natural Environment ◽  
High Throughput Sequencing ◽  
Small Scale ◽  
Human Populations ◽  
Long Distance ◽  
Antimicrobial Drugs ◽  
Clinical Resistance ◽  
Wildlife Populations ◽  
The Impact

Antimicrobial resistance (AMR) has been detected in the microbiota of many wildlife species, including long-distance migrants. Inadequately treated wastes from humans and livestock dosed with antimicrobial drugs are often assumed to be the main sources of AMR to wildlife. While wildlife populations closely associated with human populations are more likely to harbour clinically important AMR related to that found in local humans and livestock, AMR is still common in remote wildlife populations with little direct human influence. Most reports of AMR in wildlife are survey based and/or small scale, so researchers can only speculate on possible sources and sinks of AMR or the impact of wildlife AMR on clinical resistance. This lack of quantitative data on the flow of AMR genes and AMR bacteria across the natural environment could reflect the numerous AMR sources and amplifiers in the populated world. Ecosystems with relatively simple and well-characterized potential inputs of AMR can provide tractable, but realistic, systems for studying AMR in the natural environment. New tools, such as animal tracking technologies and high-throughput sequencing of resistance genes and mobilomes, should be integrated with existing methodologies to understand how wildlife maintains and disperses AMR.

Roman Seas

2020 ◽  
Author(s):  
Justin Leidwanger
Keyword(s):  
Late Antiquity ◽  
Economic Life ◽  
Small Scale ◽  
Long Distance ◽  
New Approach ◽  
Landscape Studies ◽  
Single Well ◽  
Multiple Structures ◽  
Archaeological Analysis

This book offers an archaeological analysis of maritime economy and connectivity in the Roman east. That seafaring was fundamental to prosperity under Rome is beyond doubt, but a tendency to view the grandest long-distance movements among major cities against a background noise of small-scale, short-haul activity has tended to flatten the finer and varied contours of maritime interaction and coastal life into a featureless blue Mediterranean. Drawing together maritime landscape studies and network analysis, this work takes a bottom-up view of the diverse socioeconomic conditions and seafaring logistics that generated multiple structures and scales of interaction. The material record of shipwrecks and ports along a vital corridor from the southeast Aegean across the northeast Mediterranean provides a case study of regional exchange and communication based on routine sails between simple coastal facilities. Rather than a single well-integrated and persistent Mediterranean network, multiple discrete and evolving regional and interregional systems emerge. This analysis sheds light on the cadence of economic life along the coast, the development of market institutions, and the regional continuities that underpinned integration—despite certain interregional disintegration—into Late Antiquity. Through this model of seaborne interaction, the study advances a new approach to the synthesis of shipwreck and other maritime archaeological and historical economic data, as well as a path through the stark dichotomies that inform most paradigms of Roman connectivity and trade.

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