Doppleritization of xylitic coal in the light of petrographic and chemical investigations     

Marian Wagner 《International Journal of Coal Geology》1982,2(2):181-194

The paper presents the results of petrographic and chemical investigations of xylitic coal, xylite and their ash. As is known, a xylitic coal has the function of a lithotype whereas xylites are inclusions brown coals only. All these xylites were arranged according to the increasing degree of doppleritization of xylem in the sequence: common xylite, poorly, moderately and intensely doppleritized varieties, dopplerite coal. The distinctive criteria were their differentiated physical properties, which are also reflected in the variable petrographic and chemical compositions. The petrographic differences result from the replacement of textinite by ulminite and gelinite, while the differentiation of the chemical constitution is due to the increasing carbon content and the increasing number of functional groups that determine the aromatic nature of the internal structure of the coal. Infrared absorption spectroscopy, Raman spectroscopy and chemical analysis of ash have shown that the aromatization of coal and the resulting increase in the degree of order of the structural unit are due to the formation of organomineral compounds in the course of doppleritization. It appears from the investigations that the doppleritization of vegetable matter gives rise to gels that are a mixture of organo-mineral humic compounds. The process of humification leads to the formation of gel made up of humins. It follows then that there are two ways of initial coalification of plant material, both referred to as biochemical gelification.  相似文献   

The 1 October 2001 Eruptive Prominence: Observed and Modeled Structures     

Karlický  Marian  Kotrč  Pavel  Kupryakov  Yurij A. 《Solar physics》2002,211(1-2):231-240

Using TRACE 171 Å image observations and H spectra and images observed at the Ondejov Observatory, the October 1, 2001, eruptive prominence is studied. The evolution of this prominence is described and velocities of specific parts of the prominence are determined. It was found that, after the rising phase of the cold loop-like prominence, its upper part expanded and below this expanding part, around one of its legs a `ring' structure, visible in the TRACE images, was formed. Then, at the same place, a tearing of the prominence leg was recognized. Simultaneous spectral observations of this structure reveal a very broad H line, which indicates strong turbulent motion at these positions. These processes were accompanied by an expanding H envelope. Due to the similarity of the observed `ring' and tearing structures with those modeled by Lau and Finn (1996), the prominence leg tearing is interpreted as a reconnection process between two parallel magnetic ropes having parallel electric currents, but anti-parallel axial magnetic fields.  相似文献   

KOMATIITE WITS-1, LOW CONCENTRATION NOBLE METAL STANDARD FOR THE ANALYSIS OF NON-MINERALIZED SAMPLES     

Marian TREDOUX  Iain MCDONALD 《Geostandards and Geoanalytical Research》1996,20(2):267-276

WITS-1 is a sample of silicified komatiite collected from close to the Komati River type section, near Barberton in South Africa. Two thousand kg of this komatiite was crushed and prepared for standardization. Noble metal analysis of WITS-1 has been carried out by six laboratories using four different analytical methods. The data obtained from these sources were subjected to statistical analysis (F ratio and Student t test) and a suite of "preferred" values for the noble metal concentrations are reported.  相似文献   

The role of moisture fluctuations in unsaturated transport     

Ching-Min Chang  Marian W. Kemblowski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(2):129-143

Within the framework of stochastic theory and the spectral perturbation techniques, three-dimensional dispersion in partially saturated soils with a finite correlation scale of log-hydraulic conductivity is analyzed. The effects of spatial variability of the moisture distribution parameter on the asymptotic spreading behavior of a unsaturated solute plume are assessed. This is accomplished by comparing two asymptotic macrodispersivities and two variance of solute concentration, obtained for a constant moisture content and spatially varied moisture, respectively.  相似文献   

DTSGUI: A Python Program to Process and Visualize Fiber-Optic Distributed Temperature Sensing Data     

Marian Domanski  Daven Quinn  Frederick D. Day-Lewis  Martin A. Briggs  Dale Werkema  John W. Lane Jr. 《Ground water》2020,58(5):799-804

Fiber-optic distributed temperature sensing (FO-DTS) has proven to be a transformative technology for the hydrologic sciences, with application to diverse problems including hyporheic exchange, groundwater/surface-water interaction, fractured-rock characterization, and cold regions hydrology. FO-DTS produces large, complex, and information-rich datasets. Despite the potential of FO-DTS, adoption of the technology has been impeded by lack of tools for data processing, analysis, and visualization. New tools are needed to efficiently and fully capitalize on the information content of FO-DTS datasets. To this end, we present DTSGUI, a public-domain Python-based software package for editing, parsing, processing, statistical analysis, georeferencing, and visualization of FO-DTS data.  相似文献   

A new search for features in the primordial power spectrum     

Domenico Tocchini-Valentini  Marian Douspis †  Joseph Silk 《Monthly notices of the Royal Astronomical Society》2005,359(1):31-35

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Attenuation of P and pP waves in Vrancea area – Romania     

Marian Ivan 《Journal of Seismology》2007,11(1):73-85

The seismic attenuation in the Vrancea region (Romania) is investigated from teleseismic recordings of P and pP waves during the four major, intermediate-depth Romanian events that occurred since the onset of digital instrumentation. Most stations are located in Canada and in the United States, being equipped with a variety of sensors, especially short-period ones. The amplitude spectral ratio method is used, assuming no frequency dependence of the Q _P factor in the range 0.2–2 Hz. No apparent correlation between the derived attenuation value and the type of recording sensor is observed. Lateral variations of the attenuation are obtained, with a very low Q _P area (values down to 33) located in the northwestern part of the Vrancea seismogenic volume. For the stations with different azimuth angles in relation to the epicentral area, Q _P values routinely exceed 200. Most likely, the low attenuation values are related to an upwelling mantle material located immediately beneath the crust, but limited in depth to at least 100 km.  相似文献   

Quantitative Analysis for the Cleanup of Hydrocarbon-Contaminated Soils by In-Situ Soil Venting   总被引：5，自引：0，他引：5  

Paul C. Johnson  Marian W. Kemblowski  James D. Colthart 《Ground water》1990,28(3):413-429

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Locations of Footpoints of Transequatorial Interconnecting Loops     

Fárník  František  Karlický  Marian  Švestka  Zdeněk 《Solar physics》2001,202(1):81-98

We discuss footpoints of loops seen by Yohkoh in soft X-rays that connect active regions across the equator (transequatorial interconnecting loops – TILs). While most TILs are rooted in moderately strong fields at peripheries of active regions, there are also cases when these loops are anchored in very weak or very strong fields, ranging from < 30 G to several hundred gauss. Some have their footpoints near sunspot penumbrae, creating `X-ray fountains' in a combination with active region loops. But TILs are never rooted in sunspots. The most likely explanation is that magnetic field lines leave spots almost vertically so that TILs rooted in them extend high into the corona and density in them is below the limit of visibility in X-rays. The fact that in force-free modeling some TILs are rooted in sunspots is most probably due to the difference between field-line connections in `vacuum' and in the highly conductive plasma on the Sun. Some TILs end before they reach active regions which sometimes may indicate the real situation, but mostly this `gap' is probably due to a temperature decrease near the loop footpoints which makes them invisible in X-rays. In that case the fact that these cool lowest parts of TILs are never found in TRACE or SOHO EIT images indicates that plasma density in TILs must be very low. Still, the total absence of any counterparts of X-ray TILs in TRACE and EIT images is puzzling and, therefore, other possible interpretations of the `gap' origin are also briefly mentioned.  相似文献   

Ring Current Formed During the Bombardment of a Rotating Gas Torus by Neutral Beams     

Marian Karlický 《Astrophysics and Space Science》1997,257(2):249-257

A new mechanism for the generation of the electric ring current is presented. During the radial bombardment of a rotating gas torus by a neutral beam, electrons and protons are dragged by rotating gas. Due to collisions electrons obtain the torus velocity faster than protons, therefore in some layer there is a difference in electron and proton beam toroidal velocities; the electric current is thus generated. This current is discussed as the seed magnetic field in early stages of evolving galaxies, which is then amplified by the dynamo process to present values of the magnetic field. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献