In June 2003 Hungary accepted the European Standard for Aggregates for Railway Ballast (MSZ EN 13450: 2003). The European norm, compared with the Hungarian Standard, also includes a new examination method called the micro-Deval method for railway ballast aggregates, which was previously not used in Hungary. This paper presents the test results of aggregates for railway ballast-producing quarries, according to newly accepted Standard. The test materials consist of andesite, basalt, dolomite and limestone. The results cover a significant range. The study was aimed at finding a relation between the testing methods, in order to reduce the testing procedure; however, no clear relationship was found.
This research was aimed
to investigate the role of clay on the combustion and kinetic behavior of
crude oils in limestone matrix. For this purpose, simultaneous TG (thermogravimetry)
and DTA (differential thermal analysis) experiments were performed at three
different heating rates as 10–15 and 20C min–1,
respectively. A uniform trend of decreasing activation energies was observed
with the addition of clay. It was concluded that clays surface area affects
the values of Arrhenius constant, while it is the catalytic properties of
clay, which lower the activation energies of all the reactions, involved in
the combustion process.
The Kőbánya district of Budapest is situated on the eastern margins of the Hungarian capital city. Beneath Kőbánya there is an extensive limestone layer, in which tunnels and passages have been made, some of which appear to date from the 13th century. In the 19th century, the limestone caverns of Budapest-Kőbánya were used for the refrigeration of perishable goods in large quantities. The caverns represent one of Budapest’s historical industrial landmarks, although their architectural history has not been documented in full. This article analyses the architectural development of these evidently low-tech facilities, while also exploring their significant role in the city’s urbanisation. The technical functions and structure of the system of caverns may be useful as a resource for society in the future when the supply of fossil fuels runs out. The effectiveness of the caverns as places for refrigeration can be demonstrated through climatic calculations. The cavern system has significant energy capabilities, given that there is aconstant air temperature throughout the year. The vast amount of geothermal energy could be used to cool heat pumps or heat exchangers. The results of measurements taken in preparation for this article are presented.
<a name="abs1"/>Abstract??The high temperature sulfation of CaO with SO2was investigated under vacuum by TG. Experimental data indicated that the sulfation process was a two-stage reaction, a very fast surface reaction in the beginning, and followed by a product-layer diffusion-controlled reaction. The initial period was about 7 s. This process of sulfation was affected by type of limestone, micro structure, particle size and temperature, but hardly affected by SO2concentration. A 59% CaO conversion can be achieved in 30 s at 1000?C and 1 mbar.
The massive red limestone of Tardos-Süttő popularly called red marble for its elegant looks both in the Middle Ages and today was revived as a representative building material (after the beginnings in the 12–13th centuries) by the lapidaries coming from Italy during King Matthias' reign. For the rebuilding of the Royal Palace in Buda in renaissance style, this material was used in large quantities for the moulded stone structures in addition to Buda marl (and to a far lesser extent freshwater limestone and rough stone). The 650 or so red marble carved fragments unearthed in Buda have been inventoried again in recent years within the Medium Regni program of the Széchenyi Plan. By examining each fragment in the lapidaria, we corrected and revised the manuscript formal-typological catalogue made by Emese Nagy in the 1990s. To introduce the work completed, we present a part of the catalogue and explicate a special question of reconstruction, the type of cross window with pilaster surrounds, shedding new light on certain assumptions maintained by the professional community.
Authors:Pauline Convert, Em? Márton, and János Haas
Eperkés Hill is a thoroughly studied classic exposure, yet its facies interpretation is still debated. The issue is whether Upper Triassic - lowermost Jurassic carbonates are regular beds or blocks embedded within the Kimmeridgian-Berriasian limestone. The answer to this question is important for the interpretation of the structural evolution and paleogeography of the Transdanubian Range area at the Jurassic-Cretaceous boundary; we decided therefore to contribute to the solution by applying paleomagnetism to the problem. We tested several regular beds and suspected olistoliths from two artificial exposures. In order to check the consistency of the paleomagnetic signal on site level, we drilled three or more cores from each, and subjected them to standard paleomagnetic laboratory processing and evaluation. We found that magnetic parameters were distinctly different for "regular" beds and for suspected olistoliths, but that the paleomagnetic signal was consistent within every site. However, between-site consistency was extremely high for regular beds, but was non-existent for the "megabreccia" horizon. Thus, our results confirm that older limestone was moved and re-deposited during the Late Jurassic-Early Cretaceous, indicating geodynamic conditions similar to those in the Northern Calcareous Alps.
This paper investigates the minimum oil content necessary for self-sustained combustion, which is introduced as a criterion
for the selection of suitable reservoirs for in-situ combustion processes. Differential scanning calorimetry was used to determine
the heat values of oil-limestone mixtures. The minimum temperature required for the total consumption of the fuel was obtained
by thermogravimetry (TG/DTG). The minimum amount of oil necessary to sustain combustion was calculated from these two parameters
and compared with the oil content of the reservoir. Reservoirs with an oil content greater than or equal to this minimum value
were considered feasible. It was seen that the fields examined are generally not suitable for in-situ combustion processes.
Authors:Y. Ishikawa, H. Murakami, T. Sekine, T. Saito, and K. Yoshihara
A convenient non-destructive method for the determination of low level210Pb and226Ra with an ordinary high-purity Ge-detector is presented. The ordinary Ge-detectors used in this work were available to measure 46.5 keV -rays of210Pb. These detectors were also useful for the non-destructive analysis of low-level226Ra in lime-stone and calcium chemicals when a stream of nitrogen gas was maintained around the detectors. By this method, measurements could be carried out not only for210Pb and226Ra but also for other -emitting radionuclides simultaneously, using the same detector. The detection limits of about 1 Bq per sample for210Pb and about 0.05 Bq per sample for226Ra, respectively, were estimated, when the samples were counted for 1–2 days.
The novel method of thermoluminescence (TL) dating of megalithic (cyclopean) limestone monuments and/or marble statues will be briefly reviewed. The problems and recent examples to be discussed include: (a) the determination of the accumulated archaeological dose, Dar, (b) the sample homogeneity, (c) the scattering in TL measurements, (d) the rate in solar bleaching of TL, and (e) dose-plateau inconsistencies. In retrospect, the solar bleaching of TL in some marbles refers to at least 30 mm depth, the scattering of TL measurements at best varies around ±10%, and the partial bleaching technique should be prudently applied for Dar determination. The extension of this method to date (by TL or OSL) for other rock types is discussed.
Authors:Bo-chao Xu, W. Burnett, Derek Lane-Smith, and Zhi-gang Yu
Measurements of 222Rn (“radon”) in the environment are important in the geosciences and radiation-protection fields. We demonstrate here a simple
laboratory-based calibration system to evaluate the efficiency of radon detectors with a reproducibility of about ±2%. The
system uses a closed-loop air circulation design with 226Ra adsorbed onto MnO2-impregnated fiber as a radon source. Two RAD7 radon detectors (Durridge Co., Inc.) that were precisely calibrated at Durridge’s
in-house calibration facility are used as secondary standards. By parallel analysis of the radon-enriched air within the closed
loop, the test RAD7s are assigned a calibration coefficient to be applied to future measurements. We also performed a side-by-side
intercomparison with two RAD7s in a high-radon natural environmental setting (limestone cave in Florida) that produced comparable