scholarly journals Contributions by RG Giovanelli to the Study of Magnetic Field Structures

1985 ◽  
Vol 38 (6) ◽  
pp. 775
Author(s):  
W Livingston
Keyword(s):  
Magnetic Field ◽  
Image Analysis ◽  
Solar Surface ◽  
Solar Physics ◽  
Processing System ◽  
National Observatory ◽  
Picture Processing ◽  
Surface Features ◽  
Effective Use ◽  
First Time

R. G. Giovanelli was appointed as a Visiting Scientist at Kitt Peak National Observatory for six months in both 1975 and 1979, and then for an entire year in 1981. These times proved fruitful to him as well as to the Observatory. The Vacuum Telescope and its 512-channel magnetograph had been completed and were operational. Complementing this was a new powerful 2D image analysis machine called the Interactive Picture Processing System (IPPS). For the first time, solar surface features could be quantitatively observed, usually to a seeing limited resolution composed of arcsec pixels, and then readily analysed as pictures. As is often the case, those who built the instruments remained preoccupied with their perfection, and it fell to Giovanelli to put these new tools to effective use. He did this in a series of research efforts reviewed in the present paper. Happily, he drew many of us in Tucson into his projects, injecting us with enthusiasm and enlarging our knowledge of solar physics in the process.

scholarly journals Preliminary design of the INPE's Solar Vector Magnetograph

2014 ◽  
Vol 10 (S305) ◽  
pp. 195-199 ◽  
Author(s):  
L. E. A. Vieira ◽  
A. L. Clúa de Gonzalez ◽  
A. Dal Lago ◽  
C. Wrasse ◽  
E. Echer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Visible Light ◽  
Solar Surface ◽  
Solar Physics ◽  
Solar Photosphere ◽  
Preliminary Design ◽  
Nearby Star ◽  
Surface Magnetic Field ◽  
Starting Point ◽  
The Magnetic Field

AbstractWe describe the preliminary design of a magnetograph and visible-light imager instrument to study the solar dynamo processes through observations of the solar surface magnetic field distribution. The instrument will provide measurements of the vector magnetic field and of the line-of-sight velocity in the solar photosphere. As the magnetic field anchored at the solar surface produces most of the structures and energetic events in the upper solar atmosphere and significantly influences the heliosphere, the development of this instrument plays an important role in reaching the scientific goals of The Atmospheric and Space Science Coordination (CEA) at the Brazilian National Institute for Space Research (INPE). In particular, the CEA's space weather program will benefit most from the development of this technology. We expect that this project will be the starting point to establish a strong research program on Solar Physics in Brazil. Our main aim is acquiring progressively the know-how to build state-of-the-art solar vector magnetograph and visible-light imagers for space-based platforms to contribute to the efforts of the solar-terrestrial physics community to address the main unanswered questions on how our nearby Star works.

scholarly journals A new look at sunspot formation using theory and observations

2016 ◽  
Vol 12 (S327) ◽  
pp. 46-59
Author(s):  
I. R. Losada ◽  
J. Warnecke ◽  
K. Glogowski ◽  
M. Roth ◽  
A. Brandenburg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Solar Surface ◽  
Deep Structure ◽  
Numerical Models ◽  
Solar Physics ◽  
Stratified Turbulence ◽  
Flux Tubes ◽  
Large Scale Magnetic Field ◽  
Long Time

AbstractSunspots are of basic interest in the study of the Sun. Their relevance ranges from them being an activity indicator of magnetic fields to being the place where coronal mass ejections and flares erupt. They are therefore also an important ingredient of space weather. Their formation, however, is still an unresolved problem in solar physics. Observations utilize just 2D surface information near the spot, but it is debatable how to infer deep structures and properties from local helioseismology. For a long time, it was believed that flux tubes rising from the bottom of the convection zone are the origin of the bipolar sunspot structure seen on the solar surface. However, this theory has been challenged, in particular recently by new surface observation, helioseismic inversions, and numerical models of convective dynamos. In this article we discuss another theoretical approach to the formation of sunspots: the negative effective magnetic pressure instability. This is a large-scale instability, in which the total (kinetic plus magnetic) turbulent pressure can be suppressed in the presence of a weak large-scale magnetic field, leading to a converging downflow, which eventually concentrates the magnetic field within it. Numerical simulations of forced stratified turbulence have been able to produce strong super-equipartition flux concentrations, similar to sunspots at the solar surface. In this framework, sunspots would only form close to the surface due to the instability constraints on stratification and rotation. Additionally, we present some ideas from local helioseismology, where we plan to use the Hankel analysis to study the pre-emergence phase of a sunspot and to constrain its deep structure and formation mechanism.

scholarly journals The on-axis magnetic well and Mercier's criterion for arbitrary stellarator geometries

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
P. Kim ◽  
R. Jorge ◽  
W. Dorland
Keyword(s):  
Magnetic Field ◽  
Original Work ◽  
Three Dimensional ◽  
Radial Distance ◽  
Analytical Form ◽  
One Dimensional ◽  
Modern Notation ◽  
Magnetic Well ◽  
First Time ◽  
Dimensional Integral

A simplified analytical form of the on-axis magnetic well and Mercier's criterion for interchange instabilities for arbitrary three-dimensional magnetic field geometries is derived. For this purpose, a near-axis expansion based on a direct coordinate approach is used by expressing the toroidal magnetic flux in terms of powers of the radial distance to the magnetic axis. For the first time, the magnetic well and Mercier's criterion are then written as a one-dimensional integral with respect to the axis arclength. When compared with the original work of Mercier, the derivation here is presented using modern notation and in a more streamlined manner that highlights essential steps. Finally, these expressions are verified numerically using several quasisymmetric and non-quasisymmetric stellarator configurations including Wendelstein 7-X.

scholarly journals Doppler Tomography in 2D and 3D of the X-ray Binary Cyg X-1 for June 2007

2011 ◽  
Vol 7 (S282) ◽  
pp. 201-202 ◽  
Author(s):  
O. I. Sharova ◽  
M. I. Agafonov ◽  
E. A. Karitskaya ◽  
N. G. Bochkarev ◽  
S. V. Zharikov ◽  
...  
Keyword(s):  
Binary System ◽  
Spectral Data ◽  
Inclination Angle ◽  
Tomographic Reconstruction ◽  
Orbital Plane ◽  
National Observatory ◽  
Doppler Tomography ◽  
X Ray ◽  
2D And 3D ◽  
First Time

AbstractThe 2D and 3D Doppler tomograms of X-ray binary system Cyg X-1 (V1357 Cyg) were reconstructed from spectral data for the line HeII 4686Å obtained with 2-m telescope of the Peak Terskol Observatory (Russia) and 2.1-m telescope of the Mexican National Observatory in June, 2007. Information about gas motions outside the orbital plane, using all of the three velocity components Vx, Vy, Vz, was obtained for the first time. The tomographic reconstruction was carried out for the system inclination angle of 45°. The equal resolution (50 × 50 × 50 km/s) is realized in this case, in the orbital plane (Vx, Vy) and also in the perpendicular direction Vz. The checkout tomograms were realized also for the inclination angle of 40° because of the angle uncertainty. Two versions of the result showed no qualitative discrepancy. Details of the structures revealed by the 3D Doppler tomogram were analyzed.

Micromachined Methanol Steam Reforming System Integrated With Catalytic Combustor Using Carbon Nanotubes as Catalyst Supports

2006 ◽  
Author(s):  
Dae-Eun Park ◽  
Tae-Kyu Kim ◽  
Sejin Kwon ◽  
Choong-Ki Kim ◽  
Euisik Yoon
Keyword(s):  
Carbon Nanotubes ◽  
Processing System ◽  
Pt Catalyst ◽  
Catalyst Supports ◽  
Fuel Processing ◽  
Reforming Catalyst ◽  
Coating Method ◽  
Catalytic Hydrogen ◽  
Catalytic Combustor ◽  
First Time

In this paper we have successfully demonstrated a new micromachined fuel processing system including vaporizer, catalytic combustor and methanol steam reformer. This fuel processing system utilizes the thermal energy generated from the catalytic hydrogen combustion to heat up the entire system. For the first time, we have used carbon nanotubes as a supporting structure of Pt catalyst for combustion. The catalytic combustor could supply the energy to heat the reformer and maintain its working temperature. We have also developed a new coating method of reforming catalyst (Cu/ZnO/Al2O3) and observed that adequate amount of hydrogen can be generated for PEMFC. We have successfully reported the feasibility of the proposed fuel processing system in each assembled component.

Contact resistance, coupling and hysteresis loss measurements of ITER Poloidal Field joint in parallel applied magnetic field

2021 ◽  
Author(s):  
Jianfeng Huang ◽  
Y. Ilyin ◽  
W.A.J. Wessel ◽  
Ruben Lubkemann ◽  
Erik Krooshoop ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Contact Resistance ◽  
Applied Magnetic Field ◽  
Applied Field ◽  
Simulated Data ◽  
Hysteresis Loss ◽  
Ac Loss ◽  
Field Conditions ◽  
Ac Losses ◽  
First Time

Abstract The inter-strand contact resistance and AC losses were measured on an ITER PF Coil joint in a parallel applied AC magnetic field. In addition, the hysteresis loss was measured as a function of the angle with the applied magnetic field on a NbTi strand of the same type as in the joint with a Vibrating Sample Magnetometer (VSM). The AC loss measurements were performed at four applied field conditions for combinations of 0 or 1 T offset field and 0.2 or 0.4 T sinusoidal amplitude. The hysteresis loss of the joint was compared with the measured AC loss density of the NbTi strand for the same field conditions as the joint AC loss measurement but with varying the angle of the applied field. The subsequent cable twist angles affect the hysteresis loss since the critical current and penetration field depend on the angle of the applied field. It is found that 15.5° is an effective angle for the calculation of the hysteresis loss of joint when compared to the single strand measurement. The inter-strand contact resistance measurements cover all the typical strand combinations from the five cabling stages of the individual conductors, as well as the strand combinations across the two conductors to characterize the inter-strand including the copper sole resistivity. It’s the first time to measure the contact resistances and AC losses of the full-size ITER PF joint. By comparing the measured and simulated data in the JackPot-ACDC model, it’s also the first time to obtain the accurate inter-strand, inter-petal and strand to copper sole contact resistivities, which are the main input parameters for the further quantitative numerical analysis of the PF joints, in any current and magnetic field conditions.

Use of Image Analysis for Non-Destructive Testing of Thermoformed Food Packages

2021 ◽  
Vol 36 (5) ◽  
pp. 596-607
Author(s):  
O. Ekşi
Keyword(s):  
Image Analysis ◽  
Food Packaging ◽  
Thickness Distribution ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Food Packages ◽  
Food Package ◽  
Thickness Measurements ◽  
First Time ◽  
Non Destructive

Abstract The aim of this study is to determine the thickness distribution of a food package using a non-destructive method. Initially, thickness measurements were carried out using an experimental procedure for thermoformed samples that were used for food packaging. Additionally, in this study, image analysis was used for the first time to determine the thickness distribution of the thermoformed products non-destructively. Image analysis software was employed for the estimation of thickness distribution. Measured thickness results were compared to those estimated using image analysis. Based on the results of the current study, image analysis may be an alternative method for non-destructive testing of thermoformed food packages even in a mass production line. Image analysis can be used to determine not only thickness distribution but also the weakest regions in a food package.

SMART SENSOR: AN ON-BOARD IMAGE PROCESSING SYSTEM FOR REAL-TIME REMOTE SENSING

2002 ◽  
Vol 02 (03) ◽  
pp. 481-499
Author(s):  
JANE YOU ◽  
DAVID ZHANG
Keyword(s):  
Remote Sensing ◽  
Image Analysis ◽  
Image Compression ◽  
Real Time ◽  
Processing System ◽  
Smart Sensor ◽  
Pipeline Architecture ◽  
New Approach ◽  
Hardware Processing ◽  
Sensor System Design

This paper presents a new approach to smart sensor system design for real-time remote sensing. A combination of techniques for image analysis and image compression is investigated. The proposed algorithms include: (1) a fractional discrimination function for image analysis, (2) a comparison of effective algorithms for image compression, (3) a pipeline architecture for parallel image classification and compression on-board satellites, and (4) a task control strategy for mapping image computing models to hardware processing elements. The efficiency and accuracy of the proposed techniques are demonstrated throughout system simulation.

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