scholarly journals Shock Waves and Plasma Ejection: Corpuscular and Interplanetary Evidence

1974 ◽  
Vol 57 ◽  
pp. 361-363
Author(s):  
A. J. Hundhausen
Keyword(s):  
Shock Waves ◽  
Solar Flares ◽  
Interplanetary Space ◽  
Space Exploration ◽  
Cosmic Ray ◽  
Geomagnetic Disturbances ◽  
The Past ◽  
Solar Material

The ejection of rapidly-moving solar material into interplanetary space in association with solar flares has been discussed since 1859, when geomagnetic disturbances and auroral displays followed shortly after the first observation of a flare by Carrington and Hodgson. Until the advent of in situ interplanetary observations in the early 1960's, such discussions were based upon the indirect information regarding interplanetary space that could be inferred from geomagnetic or cosmic ray data. The past decade of space exploration has provided a great deal of direct information regarding the interplanetary effects of solar flares and some quantitative implications regarding the nature of transient coronal disturbances.

Magnetic Reconnection in the Earth's Magnetotail

1985 ◽  
Vol 38 (6) ◽  
pp. 981 ◽  
Author(s):  
Edward W Hones Jr
Keyword(s):  
Solar Wind ◽  
Magnetic Reconnection ◽  
Plasma Sheet ◽  
Solar Flares ◽  
Reasonable Doubt ◽  
Physical Processes ◽  
Geomagnetic Disturbances ◽  
Magnetospheric Substorms ◽  
The Past ◽  
Fundamental Physical

Over the past few years satellite observations of the plasma sheet in the Earth's magnetotail during magnetospheric substorms have established beyond reasonable doubt that magnetic reconnection occurs in the magnetotail and that it plays a central role in the substorm process. The features seen at Earth by which substorms were originally identified (e.g. the auroras and geomagnetic disturbances) are simply superficial manifestations of a more fundamental physical process-the magnetosphere divesting itself of stored energy and plasma that was acquired earlier from the solar wind. It does so by shedding a part of its plasma sheet. This is accomplished by magnetic reconnection near the Earth that severs the plasma sheet, forming a plasmoid that flows out of the tail and that is lost to the solar wind. Recognition of the existence of plasmoids and our developing understanding of them have been important elements in confirming the occurrence of reconnection in the magnetosphere. In an analogous way, the best evidence for the occurrence of reconnection on the Sun has come from observations of closed magnetic configurations (plasmoids) in the solar wind and in the corona. But while magnetic reconnection is certainly the key ingredient in solar flares and substorms, analogies between them should not be carried too far, because there are basic differences in the environments in which they prevail and in the physical procesSes that lead to their occurrence.

scholarly journals Theoretical and Experimental Aspects of Solar Flares Manifestation in Radiocarbon Abundance in Tree Rings

Radiocarbon ◽  
1992 ◽  
Vol 34 (2) ◽  
pp. 247-253 ◽  
Author(s):  
A. N. Kostantinov ◽  
V. A. Levchenko ◽  
G. E. Kocharov ◽  
I. B. Mikheeva ◽  
Stefano Cecchini ◽  
...  
Keyword(s):  
Tree Rings ◽  
Solar Flares ◽  
High Probability ◽  
Cosmic Ray ◽  
Cosmogenic Isotopes ◽  
The Past ◽  
Cosmic Ray Flux ◽  
Several Intervals

We describe our method of determining solar cosmic-ray flux and spectrum in the past, based on the comparison of different cosmogenic isotopes. For the period, AD 1781–1950, we have detected several intervals with a high probability of powerful solar flares.

Solar Flare Increase of Cosmic Ray Intensity on November 22, 1977

1978 ◽  
Vol 3 (3) ◽  
pp. 238-241 ◽  
Author(s):  
A. G. Fenton ◽  
K. B. Fenton ◽  
J. E. Humble
Keyword(s):  
Solar Flares ◽  
Average Rate ◽  
Sunspot Cycle ◽  
Cosmic Ray ◽  
Ground Level ◽  
Solar Cycles ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
The Past ◽  
The World

Solar flares for which protons of relativistic energies reach Earth are rare events compared with the number in which non-relativistic protons are produced. For instance, Shea and Smart (1978) have listed 139 proton events for the interval 1955-69 of which 17 were GLE’s (i.e. “ground level events” detected by the world network of cosmic ray neutron monitors). We have tentatively identified a further 11 GLE’s in the interval 1970-1977, of which 3 were in 1977 in the sunspot cycle which commenced about mid-1976 (cycle 21). Thus the average rate over the past two solar cycles has been a little over one per year.

CRITERIA FOR THE ASSOCIATION OF SOLAR FLARES WITH GEOMAGNETIC DISTURBANCES

1963 ◽  
Vol 41 (7) ◽  
pp. 1056-1075 ◽  
Author(s):  
R. W. Jenkins ◽  
Irvine Paghis
Keyword(s):  
Solar Flares ◽  
Maximum Concentration ◽  
Cosmic Ray ◽  
Ground Level ◽  
Detailed Examination ◽  
Sudden Commencement ◽  
Strong Positive Correlation ◽  
Geomagnetic Disturbances ◽  
Wide Range ◽  
East West

The statistical relation between solar flares of importance [Formula: see text] and the onset of geomagnetic disturbances was studied for 1949–61. Disturbances were defined as an increase in ap[Formula: see text], occurring within 12 hours or less, and these disturbances include both gradual and sudden commencement events. Associated radio noise bursts at frequencies below 300 Mc were used to select 240 major-burst flares, and the effects of flare importance, time of solar epoch, and associated polar-cap-absorption (PCA) events were considered in turn. A detailed examination was made of the effect of flare heliographic location. There is a strong positive correlation between the occurrence of major-burst flares and geomagnetic disturbances 1 to 3 days afterwards. The degree of correlation is approximately doubled when the major-burst flare is associated with a PCA event. The most probable time delay between flares and disturbances is 1.5 to 2.0 days, and this timing is relatively constant over a wide range of conditions.The dominance of northern storm-flares (Bell 1961) was confirmed for 1949–61. Detailed analysis shows that the effect is strongest for heliographic latitudes above 15 °N. In addition to this effect, there was a consistent western bias of the storm-flares in both the northern and southern hemispheres, for flares associated with either gradual or sudden commencement (SC) events, with maximum concentration occurring at 10 °W. to 15 °W. Major-burst flares associated with PCA events also show this western bias; the data suggest that there is a systematic increase in east–west asymmetry in going from major-burst storm-flares to major-burst PCA flares to PCA flares accompanied by ground-level cosmic-ray increases. The corresponding longitudes of maximum concentration of the associated flares are about 10 °– 15 °W., 45 °W., and 75 °W.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

In situ microprobe quantitation of inorganic particle burden in paraffin sections of lung tissue

1988 ◽  
Vol 46 ◽  
pp. 990-991
Author(s):  
Jerrold L. Abraham
Keyword(s):  
Lung Tissue ◽  
Quantitative Information ◽  
Particulate Material ◽  
Paraffin Sections ◽  
Tissue Samples ◽  
Qualitative And Quantitative ◽  
The Past ◽  
Quantitative Analyses ◽  
Data Result

Inorganic particulate material of diverse types is present in the ambient and occupational environment, and exposure to such materials is a well recognized cause of some lung disease. To investigate the interaction of inhaled inorganic particulates with the lung it is necessary to obtain quantitative information on the particulate burden of lung tissue in a wide variety of situations. The vast majority of diagnostic and experimental tissue samples (biopsies and autopsies) are fixed with formaldehyde solutions, dehydrated with organic solvents and embedded in paraffin wax. Over the past 16 years, I have attempted to obtain maximal analytical use of such tissue with minimal preparative steps. Unique diagnostic and research data result from both qualitative and quantitative analyses of sections. Most of the data has been related to inhaled inorganic particulates in lungs, but the basic methods are applicable to any tissues. The preparations are primarily designed for SEM use, but they are stable for storage and transport to other laboratories and several other instruments (e.g., for SIMS techniques).

An atomic-resolution microscope study of Al contracts on GaAs

1986 ◽  
Vol 44 ◽  
pp. 726-727
Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn
Keyword(s):  
High Speed ◽  
Schottky Contacts ◽  
Detailed Knowledge ◽  
The Past ◽  
Semiconductor Interfaces ◽  
Deposited Metal ◽  
Microwave Applications ◽  
Free Interfaces ◽  
Potential Use

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions

The concept of the flat earth in the holy scripture

2020 ◽  
Vol 1 (100) ◽  
pp. 77-82
Author(s):  
V.P. Kultenko ◽  
◽  
K.M. Mamchur ◽  
Keyword(s):  
Old Testament ◽  
Space Exploration ◽  
Practical Experience ◽  
Modern World ◽  
Cultural Experience ◽  
Religious Texts ◽  
Sacred Texts ◽  
The Past

The article deals with the concept of flat Earth. There has a adherents and defenders in the modern world, despite the solid age of heliocentric teaching. Flat Earth apologists point out, that the evidence in favor of the scientific heliocentric theory is held on confidence. People should trust the testimony of astronauts, space exploration data, and more. However, the vast majority of people cannot verify this data from their own practical experience. If science is a criterion for truth, then the heliocentric concepts and flat Earth are far removed from this criterion. Moreover, in the cultural experience of the past we can find arguments in favor of the concept of a flat Earth. These testimonies are contained, in particular, in the Old Testament Bible, the sacred texts of Christianity and Judaism. The mythological and religious texts of other nations and cultures also refer to the idea of a flat Earth.

scholarly journals 3D-Bioprinting Strategies Based on In Situ Bone-Healing Mechanism for Vascularized Bone Tissue Engineering

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 287
Author(s):  
Ye Lin Park ◽  
Kiwon Park ◽  
Jae Min Cha
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Bone Healing ◽  
Critical Size ◽  
Current Knowledge ◽  
3D Bioprinting ◽  
The Past ◽  
Regeneration Processes

Over the past decades, a number of bone tissue engineering (BTE) approaches have been developed to address substantial challenges in the management of critical size bone defects. Although the majority of BTE strategies developed in the laboratory have been limited due to lack of clinical relevance in translation, primary prerequisites for the construction of vascularized functional bone grafts have gained confidence owing to the accumulated knowledge of the osteogenic, osteoinductive, and osteoconductive properties of mesenchymal stem cells and bone-relevant biomaterials that reflect bone-healing mechanisms. In this review, we summarize the current knowledge of bone-healing mechanisms focusing on the details that should be embodied in the development of vascularized BTE, and discuss promising strategies based on 3D-bioprinting technologies that efficiently coalesce the abovementioned main features in bone-healing systems, which comprehensively interact during the bone regeneration processes.

scholarly journals Cosmic-Ray Driven Outflows to Mpc Scales from L* Galaxies

2020 ◽  
Author(s):  
Philip F Hopkins ◽  
T K Chan ◽  
Suoqing Ji ◽  
Cameron B Hummels ◽  
Dušan Kereš ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Plane Layer ◽  
Equilibrium Density ◽  
Pressure Gradients ◽  
Low Velocity ◽  
Star Forming ◽  
Stellar Feedback ◽  
Massive Halos ◽  
Halo Masses

Abstract We study the effects of cosmic rays (CRs) on outflows from star-forming galaxies in the circum and inter-galactic medium (CGM/IGM), in high-resolution, fully-cosmological FIRE-2 simulations (accounting for mechanical and radiative stellar feedback, magnetic fields, anisotropic conduction/viscosity/CR diffusion and streaming, and CR losses). We showed previously that massive (Mhalo ≳ 1011 M⊙), low-redshift (z ≲ 1 − 2) halos can have CR pressure dominate over thermal CGM pressure and balance gravity, giving rise to a cooler CGM with an equilibrium density profile. This dramatically alters outflows. Absent CRs, high gas thermal pressure in massive halos “traps” galactic outflows near the disk, so they recycle. With CRs injected in supernovae as modeled here, the low-pressure halo allows “escape” and CR pressure gradients continuously accelerate this material well into the IGM in “fast” outflows, while lower-density gas at large radii is accelerated in-situ into “slow” outflows that extend to >Mpc scales. CGM/IGM outflow morphologies are radically altered: they become mostly volume-filling (with inflow in a thin mid-plane layer) and coherently biconical from the disk to >Mpc. The CR-driven outflows are primarily cool (T ∼ 105 K) and low-velocity. All of these effects weaken and eventually vanish at lower halo masses (≲ 1011 M⊙) or higher redshifts (z ≳ 1 − 2), reflecting the ratio of CR to thermal+gravitational pressure in the outer halo. We present a simple analytic model which explains all of the above phenomena. We caution that these predictions may depend on uncertain CR transport physics.

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