Spatial characteristics of electric current and field in large direct-current coronas

1993 ◽  
Vol 441 (1911) ◽  
pp. 125-146 ◽  
Keyword(s):  
Space Charge ◽  
Direct Current ◽  
Current Density ◽  
Applied Field ◽  
Current Flow ◽  
Reasonable Accuracy ◽  
The Past ◽  
Field Distributions ◽  
Relationship Of ◽  
Very High

The distribution of corona currents arising at the plane of a rod/plane gap has been studied for the past 90 years by using small gaps ranging from 25 to 200 mm but it has not been known until recently whether this distribution changes markedly when the gap is increased to several metres, the sort of gap which is encountered in buildings where very high direct voltages are generated or distributed. The flow of corona creates a space-charge which, in turn, modifies the electric gradient across the gap; such gradients have not previously been measured in large gaps. The present paper reports the current density and field distributions over the plane of rod/plane gaps up to 3 m. The time taken for the space-charge to drift across the gap and the length of the trajectory have been deduced so that a general model of the current flow has been constructed with reasonable accuracy. The inter-relationship of the modification by space-charge of the original applied field and the current density has been established experimentally and theoretically. The phenomena have been studied for corona of both polarities.

Electrochemical Synthesis of Conducting Polypyrrole Film on Tin Substrate: Structural, Chemical and Field Emission Investigations

2015 ◽  
Vol 36 ◽  
pp. 44-50 ◽  
Author(s):  
Pankaj M. Koinkar ◽  
Sandip S. Patil ◽  
Toshihiro Moriga ◽  
Mahendra A. More
Keyword(s):  
Field Emission ◽  
Current Density ◽  
Electrochemical Synthesis ◽  
Applied Field ◽  
Emission Current Density ◽  
Emission Current ◽  
Threshold Field ◽  
Potential Candidate ◽  
High Emission ◽  
Very High

Electrochemical synthesis of Polypyrrole (PPy) thin films on Sn substrates has been carried out under cyclic voltammetry (CV) mode. The structural, morphological and chemical properties of the as-synthesized PPy films were investigated using various characterization techniques like SEM, UV-Visible and FTIR. Furthermore, field emission (FE) behaviour of the PPy thin film emitter were carried out at base pressure of ~ 1×10-8 mbar and found to be interesting. The threshold field, required to draw emission current density of 1 μA/cm2, is observed to be 0.90 V/μm and very high emission current density of 12.87 mA/cm2 has been drawn at applied field of ~ 2.8 V/μm. The emission current stability investigated at preset values of 1, 10 and 100 μA/cm2 is observed to be fairly good over duration of more than three hours. The simplicity of the synthesis route coupled with the capability to deliver very high emission current density at relatively lower applied field make the PPy thin field emitter as a potential candidate for practical applications in field emission based devices

Microstructure Development in a High Current Density NbTi Superconducting Composite

1985 ◽  
Vol 43 ◽  
pp. 186-189
Author(s):  
P. J. Lee ◽  
D. C. Larbalestier
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cold Drawing ◽  
Heat Treatments ◽  
Grain Structure ◽  
Fine Grain ◽  
Boundary Film ◽  
Quantitative Basis ◽  
Cold Worked ◽  
Very High

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.

Editor's Note

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Emily Kaliel
Keyword(s):  
Civil War ◽  
Public Memory ◽  
Historical Memory ◽  
Historical Analysis ◽  
Red River ◽  
Cultural Institutions ◽  
Economic Rights ◽  
The Past ◽  
Relationship Of

The articles published in our Fall 2016 edition are connected loosely under the themes of public memory and the uses of identity in the past. We are thrilled to present to you three excellent articles in our Fall 2016 edition: The article "Dentro de la Revolución: Mobilizing the Artist in Alfredo Sosa Bravo's Libertad, Cultura, Igualdad (1961)" analyzes Cuban artwork as multi-layered work of propaganda whose conditions of creation, content, and exhibition reinforce a relationship of collaboration between artists and the state-run cultural institutions of post-revolutionary Cuba; moving through fifty years of history “’I Shall Never Forget’: The Civil War in American Historical Memory, 1863-1915" provides a captivating look at the role of reconciliationist and emancipationist intellectuals, politicians, and organizations as they contested and shaped the enduring memory of the Civil War; and finally, the article “Politics as Metis Ethnogenesis in Red River: Instrumental Ethnogenesis in the 1830s and 1840s in Red River” takes the reader through a historical analysis of the development of the Metis identity as a means to further their economic rights. We wholly hope you enjoy our Fall 2016 edition as much as our staff has enjoyed curating it. Editors  Jean Middleton and Emily Kaliel Assistant Editors Magie Aiken and Hannah Rudderham Senior Reviewers Emily Tran Connor Thompson Callum McDonald James Matiko Bronte Wells

IV.—The Geological Development, Descent and Distribution of the Mammalia

1893 ◽  
Vol 10 (9) ◽  
pp. 401-412 ◽  
Author(s):  
Karl A. von Zittel
Keyword(s):  
South America ◽  
The Past ◽  
Limited Experience ◽  
The World ◽  
Relationship Of ◽  
North And South America ◽  
The Relationship ◽  
North And South ◽  
Animal World

In a spirited treatise on the ‘Origin of our Animal World’ Prof. L. Rütimeyer, in the year 1867, described the geological development and distribution of the mammalia, and the relationship of the different faunas of the past with each other and with that now existing. Although, since the appearance of that masterly sketch the palæontological material has been, at least, doubled through new discoveries in Europe and more especially in North and South America, this unexpected increase has in most instances only served as a confirmation of the views which Rutimeyer advanced on more limited experience. At present, Africa forms the only great gap in our knowledge of the fossil mammalia; all the remaining parts of the world can show materials more or less abundantly, from which the course followed by the mammalia in their geological development can be traced with approximate certainty.

scholarly journals A review on the production, structure, bioactivities and applications of Tremella polysaccharides

2021 ◽  
Vol 35 ◽  
pp. 205873842110005
Author(s):  
Xia Ma ◽  
Meng Yang ◽  
Yan He ◽  
Chuntao Zhai ◽  
Chengliang Li
Keyword(s):  
Biologically Active ◽  
Research Progress ◽  
Research Trend ◽  
Production Structure ◽  
Health States ◽  
Preparation Methods ◽  
The Past ◽  
Structure Activity ◽  
Relationship Of ◽  
Active Natural

Tremella polysaccharide is known to be structurally unique and biologically active natural products, abundant and versatile in activities and applications in food industry, daily chemical industry and medicine industry. In order to improve the industrialisation of Tremella polysaccharide, the limitations of preparation and structure-activity relationship of Tremella polysaccharide were reviewed in this paper. The research progress of Tremella polysaccharide in the past 20 years was summarized from the sources, preparation methods, molecular structure, activity and application, and the research trend in the future was also prospected. The application prospect of Tremella polysaccharide in against multiple sub-health states was worth expecting.

scholarly journals Cardiorespiratory Functioning in Youth with Persistent Post-Concussion Symptoms: A Pilot Study

2021 ◽  
Vol 10 (4) ◽  
pp. 561
Author(s):  
Aliyah Snyder ◽  
Christopher Sheridan ◽  
Alexandra Tanner ◽  
Kevin Bickart ◽  
Molly Sullan ◽  
...  
Keyword(s):  
Processing Speed ◽  
Mean Value ◽  
Exhaled Breath ◽  
Post Injury ◽  
The Past ◽  
Neurobehavioral Outcomes ◽  
End Tidal ◽  
Relationship Of ◽  
The Relationship ◽  
End Tidal Co2

Dysregulation of the autonomic nervous system (ANS) may play an important role in the development and maintenance of persistent post-concussive symptoms (PPCS). Post-injury breathing dysfunction, which is influenced by the ANS, has not been well-studied in youth. This study evaluated cardiorespiratory functioning at baseline in youth patients with PPCS and examined the relationship of cardiorespiratory variables with neurobehavioral outcomes. Participants were between the ages of 13–25 in two groups: (1) Patients with PPCS (concussion within the past 2–16 months; n = 13) and (2) non-injured controls (n = 12). Capnometry was used to obtain end-tidal CO2 (EtCO2), oxygen saturation (SaO2), respiration rate (RR), and pulse rate (PR) at seated rest. PPCS participants exhibited a reduced mean value of EtCO2 in exhaled breath (M = 36.3 mmHg, SD = 2.86 mmHg) and an altered inter-correlation between EtCO2 and RR compared to controls. Neurobehavioral outcomes including depression, severity of self-reported concussion symptoms, cognitive catastrophizing, and psychomotor processing speed were correlated with cardiorespiratory variables when the groups were combined. Overall, results from this study suggest that breathing dynamics may be altered in youth with PPCS and that cardiorespiratory outcomes could be related to a dimension of neurobehavioral outcomes associated with poorer recovery from concussion.

scholarly journals Truck Appointment System for Cooperation between the Transport Companies and the Terminal Operator at Container Terminals

2020 ◽  
Vol 11 (1) ◽  
pp. 168
Author(s):  
Hyeonu Im ◽  
Jiwon Yu ◽  
Chulung Lee
Keyword(s):  
Large Scale ◽  
Container Terminal ◽  
Container Terminals ◽  
The Past ◽  
Cooperation Model ◽  
Appointment System ◽  
New Form ◽  
Truck Appointment System ◽  
Import Container ◽  
Very High

Despite the number of sailings canceled in the past few months, as demand has increased, the utilization of ships has become very high, resulting in sudden peaks of activity at the import container terminals. Ship-to-ship operations and yard activity at the container terminals are at their peak and starting to affect land operations on truck arrivals and departures. In response, a Truck Appointment System (TAS) has been developed to mitigate truck congestion that occurs between the gate and the yard of the container terminal. The vehicle booking system is developed and operated in-house at large-scale container terminals, but efficiency is low due to frequent truck schedule changes by the transport companies (forwarders). In this paper, we propose a new form of TAS in which the transport companies and the terminal operator cooperate. Numerical experiments show that the efficiency of the cooperation model is better by comparing the case where the transport company (forwarder) and the terminal operator make their own decision and the case where they cooperate. The cooperation model shows higher efficiency as there are more competing transport companies (forwarders) and more segmented tasks a truck can reserve.

Space‐charge‐limited current flow in a spherical double sheath

1986 ◽  
Vol 60 (7) ◽  
pp. 2280-2284 ◽  
Author(s):  
Ronghua Wei ◽  
Paul J. Wilbur
Keyword(s):  
Space Charge ◽  
Current Flow ◽  
Space Charge Limited Current ◽  
Limited Current ◽  
Space Charge Limited

Septic Shock

1992 ◽  
Vol 7 (2) ◽  
pp. 90-100 ◽  
Author(s):  
Margaret M. Parker ◽  
Mitchell P. Fink
Keyword(s):  
Septic Shock ◽  
Supportive Care ◽  
Antimicrobial Therapy ◽  
Clinical Manifestations ◽  
Sepsis Syndrome ◽  
Adjunctive Treatment ◽  
Cardiovascular Changes ◽  
The Past ◽  
Sepsis And Septic Shock ◽  
Very High

The incidence of sepsis and septic shock has been increasing dramatically over the past 10 years. Despite advances in antimicrobial therapy, the mortality of septic shock remains very high. We review the clinical manifestations of sepsis and septic shock and describe the cardiovascular manifestations. Pathophysiology of the cardiovascular changes is discussed, and mediators believed to be involved in the pathogenesis are reviewed. Management of septic shock is also discussed, including antimicrobial therapy, supportive care, and adjunctive treatment aimed at affecting the mediators involved in producing the sepsis syndrome.

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