scholarly journals Seleno-aluminium bridges

1908 ◽  
Vol 81 (544) ◽  
pp. 9-21
Keyword(s):  
Thin Layer ◽  
Thin Plate ◽  
Plane Surface ◽  
Narrow Layer ◽  
Circular Form ◽  
The Face ◽  
Narrow Space ◽  
A Current

A seleno-aluminium bridge consists of a very thin and narrow layer of conducting selenium connecting two surfaces of aluminium which are separated by an insulator, such as glass or mica. The bridge may have a linear or a circular form. If the first, it is made thus: let P and Q be two strips of aluminium separated by a very thin plate of mica SS; the hole, as we look at the figure, forms a perfectly plane surface. If the plates P, Q are connected with a galvano­meter G and a battery B of a few cells, no current passes because of the insulation of the mica; but if we smear a thin layer of melted selenium over the surfaces of the plates, and, of course, over the mica, and then heat this layer in the well-known way until the selenium assumes the brownish grey modification which conducts a current, the narrow space of mica insulation is bridged over by a conductor, and the current of the battery passes. This bridge will have a certain conductivity in the dark, and that conductivity, as we shall see, will depend on the voltage of the battery. If light—even the feeble light of a distant candle—is allowed to fall on the face of the bridge, the conductivity is very much increased, and the galvanometer will show a much increased current.

Facial Surface Anthropometric Features and Measurements With an Emphasis on Rhinoplasty

2021 ◽  
Author(s):  
M Mazhar Celikoyar ◽  
Michael F Perez ◽  
M Ilhan Akbas ◽  
Oguzhan Topsakal
Keyword(s):  
Surgical Planning ◽  
Medical Literature ◽  
Facial Features ◽  
Post Surgery ◽  
Anthropometric Features ◽  
The Face ◽  
Narrative Literature ◽  
Narrative Literature Review ◽  
Objective Outcomes ◽  
A Current

Abstract Background Facial features and measurements are utilized to analyze patients’ faces for various reasons, including surgical planning, scientific communications, patient-surgeon communications, and post-surgery evaluations. Objectives There are numerous descriptions regarding these features and measurements scattered throughout the literature and we did not encounter a current compilation of these parameters in the medical literature. Methods A narrative literature review of the published medical literature for facial measurements used for facial analysis in rhinoplasty was done through the electronic databases MEDLINE/PubMed and Google Scholar, along with a citation search. Results A total of 61 facial features were identified. 45 points (25 bilateral, 20 unilateral), five lines (three bilateral, two unilateral), eight planes, and three areas. A total of 122 measurements were identified: 48 distances (6 bilateral, 42 unilateral), 57 angles (13 bilateral, 44 unilateral), and 17 ratios. Supplemental Figures were created to depict all features and measurements using either a frontal, lateral or basal view of the face. Conclusions This paper provides the most comprehensive and current compilation of facial measurements to date. We believe this compilation will guide further developments (methodologies and software tools) for analyzing nasal structures and assessing the objective outcomes of facial surgeries, in particular rhinoplasty. Moreover, it will improve the communication as a reference for facial measurements of facial surface anthropometry, in particular rhinoplasty.

Immigrant Neurologists in the United States: The Path of Most Resistance

Neurology ◽  
2020 ◽  
pp. 10.1212/WNL.0000000000011196
Author(s):  
Abhimanyu Mahajan ◽  
Zachary London ◽  
Andrew M. Southerland ◽  
Jaffar Khan ◽  
Erica Schuyler
Keyword(s):  
United States ◽  
Private Practice ◽  
The United States ◽  
Vital Role ◽  
International Medical Graduates ◽  
Medical Graduates ◽  
The Face ◽  
Healthcare Crisis ◽  
A Current ◽  
The U.S

International Medical Graduates (IMGs), individuals who graduated from medical school outside of the United States or Canada, constitute 31.3% of active neurologists and one-third of current neurology trainees. While three-fourths of IMG neurology trainees are not U.S. citizens, they are an integral part of our trainee and practice workforce. IMGs play a vital role in providing greater access to healthcare for millions of patients, particularly in traditionally underserved regions and in the face of a current global healthcare crisis.With this article, we outline some of the unique challenges faced by immigrant, U.S.-trained neurologists as they seek to provide neurological care across the country, including preparing and applying for residency, securing authorization to remain in the U.S. to practice, and positioning themselves for successful careers in academic and private practice. We also call for advocacy and legislation to help reduce these barriers as a means to address the increasing physician workforce gap.

Direct Measurement of Hot-spot Temperature in Flip-chip Solder Joints With Cu Columns Under Current Stressing using Infrared Microscopy

2010 ◽  
Vol 1249 ◽  
Author(s):  
Chih Chen ◽  
Yu Chun Liang ◽  
D. J. Yao
Keyword(s):  
Thin Layer ◽  
Flip Chip ◽  
Solder Bump ◽  
Hot Spot ◽  
Infrared Microscopy ◽  
Column Temperature ◽  
Current Stressing ◽  
Large Current ◽  
Spot Temperature ◽  
A Current

AbstractIn this study, the temperature map distribution in the Sn3.0Ag0.5Cu solder bump with Cu column under current stressing is directly examined using infrared microscopy. It is the radiance changes between the different materials of the surface that cause the unreasonable temperature map distribution. By coating a thin layer of black optical paint which is in order to eliminate the radiance changes, we got the corrected temperature map distribution. Under a current stress of 1.15 × 104 A/cm2 at 100℃C, the hot-spot temperature is 132.2℃ which surpasses the average Cu column temperature of 129.7℃C and the average solder bump temperature of 127.4 ℃. Thermomigration in solder may still occur under a large current stressing.

scholarly journals VI. On the capillary phenomena of jets

1879 ◽  
Vol 29 (196-199) ◽  
pp. 71-97 ◽  
Keyword(s):  
High Pressure ◽  
Thin Plate ◽  
Capillary Phenomena ◽  
Circular Form ◽  
Circular Orifice ◽  
Water Issues

When water issues under high pressure from a circular orifice in a thin plate, a jet is formed whose section, though diminished in area, retains the circular form. But if the orifice be not circular, the section of the jet undergoes remarkable transformations, which were elaborately investigated by Bidone, many years ago.

Effects of Cathode-Mandrel Surface Irregularities on the Mechanical Properties and Structure of Electroformed Iron Foil

1980 ◽  
Vol 22 (2) ◽  
pp. 49-54 ◽  
Author(s):  
W. A. Crichton ◽  
J. A. McGeough ◽  
J. R. Thomson
Keyword(s):  
Surface Roughness ◽  
Current Density ◽  
Cathode Surface ◽  
Foil Thickness ◽  
Iron Foil ◽  
Surface Irregularities ◽  
The Face ◽  
The Relationship ◽  
A Current ◽  
Cathodic Surface

Iron foil, of thicknesses between 003 and 0.15 mm has been electroformed at a current density of 30 A/dm2 and an electrolyte temperature of 100°C upon cathodes of surface roughness ranging from 0.04 to 4.4 μm Ra. The surface roughnesses of the face of the foil formed adjacent to the cathode, and of that electrode, are similar. The roughness of the reverse anodic face increases with increasing foil thickness, due to the increase in size of the crystal growth sites. The hardness of the cathodic face of the foil is unaffected by either cathode surface roughness or foil thickness. The hardness of the anodic face increases with both increasing cathode surface roughness and decreasing foil thickness, due to corresponding changes in grain size. A slight net decrease in tensile properties with increasing cathode surface roughness is attributed to the greater amount of stress concentration borne by the rougher foils. Young's modulus for the foil is not affected by cathode surface roughness. The electroforming of foil upon a mandrel surface carrying an isolated V-shaped scratch, 0.14 mm deep and 0.28 mm wide, has also been studied by numerical and experimental methods. The cathodic surface of foil is found to adopt the shape of the scratch whilst its upper side becomes level. The effect upon the geometric configuration of the foil depends upon the relationship between current efficiency and current density for the electrolyte, and on the polarisation (overpotential) characteristics at the mandrel surface.

As Vantagens da Biorremediação na Qualidade Ambiental

2019 ◽  
Vol 23 (1) ◽  
pp. 12
Author(s):  
Viviane Mallmann ◽  
Lucas Wagner Ribeiro Aragão ◽  
Shaline Séfara Lopes Fernandes ◽  
Tauane Catilza Lopes Fernandes ◽  
Roberta Fernanda Ribeiro Aragão ◽  
...  
Keyword(s):  
Natural Resources ◽  
Environmental Impacts ◽  
Low Cost ◽  
Sustainable Production ◽  
The Face ◽  
A Current

Perante o uso desmedido dos recursos naturais surge uma corrida em busca de encontrar alternativas possíveis de recuperação desses ecossistemas. E este artigo traz uma revisão bibliográfica com o intuito de apontar alguns aspectos, que vêm sendo discutidos por pesquisadores no campo da biorremediação como técnica de reversão de contaminantes, bem como de apontamentos de ações futuras que podem vir a ser realizadas para minimizar os impactos ambientais. Entre os apontamentos realizados pelos diferentes autores consultados para este manuscrito, fica evidenciado que as técnicas de descontaminação são onerosas e algumas ainda apresentam subprodutos tóxicos em seus processos. Em alternativa a esta realidade se buscou, ao longo dos anos, meios para solucionar estes problemas, e a biorremediação ganhou espaço em detrimento de suas vantagens. De acordo com os autores das bibliografias consultadas, a biorremediação, além de utilizar seres vivos na tentativa de recuperar estes ambientes degradados apresenta custo baixo e vem ganhando, atualmente, difusão no Brasil. Todavia, alguns pesquisadores apontam, em seus estudos, que não basta haver uma corrente em busca de alternativas com estas características para remediar os ambientes impactados, é necessário haver consciência e políticas mais severas que se atentem para vir a garantir uma produção mais sustentável sem degradar o ambiente. Palavras-chave: Recursos Naturais. Políticas. Produção Sustentável. Ambientes impactados. Descontaminação AbstractIn the face of the excessive use of natural resources, a race is underway to find possible alternatives for the recovery of such  ecosystems. And this article brings a bibliographical review with the intention of pointing out some aspects that  have been discussed by researchers in the field of bioremediation as a technique for reversing contaminants as well as notes of future actions that can be carried out to minimize the environmental impacts. Among the notes made by the different authors consulted for this manuscript, it is evidenced that the decontamination techniques are costly and some still have toxic byproducts in their processes. As an alternative to this reality, over the years efforts have been made to solve these problems, and bioremediation has gained space to the detriment of its advantages. According to the authors of the consulted bibliographies, bioremediation, in addition to using living beings in an attempt to recover these degraded environments present a low cost and has been gaining, currently, diffusion in Brazil. However, some researchers point out in their studies that it is not enough to have a current in search of alternatives with these characteristics to remedy impacted environments, it is necessary to have awareness and more severe policies that are taken care to ensure a more sustainable production without degrading the environment. Keywords: Natural Resources. Policies. Sustainable Production. Impacted Environments. Decontamination.

The Formative Phase of a Low Pressure, High Voltage Z Pinch

1972 ◽  
Vol 50 (20) ◽  
pp. 2475-2481 ◽  
Author(s):  
C. S. Maclatchy ◽  
A. J. Barnard
Keyword(s):  
Spatial Distribution ◽  
Energy Spectrum ◽  
Current Layer ◽  
Exact Nature ◽  
Axial Region ◽  
Total Discharge Current ◽  
The Face ◽  
Z Pinch ◽  
Total Discharge ◽  
A Current

The formative phase of a 40 kV Z pinch has been investigated for pressures from 10 to 80 mTorr in H2. The energy spectrum of the electrons on the axis of the vessel, the spatial distribution of the current at the face of the anode, and the total discharge current were monitored. At the initiation of the discharge, a current of electrons with energies in excess of 20 keV is observed on the axis. This observation is in contrast to the normally accepted mode of ionization in which ionization initiates at the wall. The current is observed to switch from the axial region to the wall where it forms a current layer which collapses in accordance with the snow-plough model. The exact nature of the switching mechanism is not understood. The formative phase of the pinch typically takes a few hundred nanoseconds. The observations indicate that the detailed process of current sheet collapse may be affected by the formative phase.

Development of charge-transport and thermoelectric simulation methodology based on density functional theory and application to organic materials

Impact ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 32-34
Author(s):  
Hiroyuki Ishii
Keyword(s):  
Organic Semiconductors ◽  
Carbon Nanostructures ◽  
Density Functional ◽  
Applied Physics ◽  
Free Electrons ◽  
Functional Theory ◽  
Simulation Methodology ◽  
The Face ◽  
A Current ◽  
Observable Phenomenon

Physics is constantly evolving. It is a field that attempts to create calculations and theories capable of completely describing an observable phenomenon. The ability of various materials to conduct heat and electricity can vary wildly. Insulators can be 20 orders of magnitude less conductive than the best conductors, with everything in between also possible. Conductivity is related to the creation of a material capable of providing free electrons for the transfer of a current through the material. However, the current theories for the calculation of these conductive capacity have proved insufficient in the face of novel compounds such as carbon nanostructures and organic semiconductors. Professor Hiroyuki Ishii of Faculty of Pure and Applied Physics, University of Tsukuba, Japan, is attempting to address this disparity with the support of a team of physicists based at the Faculty of Pure and Applied Physics, University of Tsukuba.

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