Authors:A G Aronov, R R Seroglazov, T I Aronova, and O N Safronov
The paper deals with the earthquakes that took place in the Kaliningrad region (Russia) on 21 September 2004 and were felt in the territories of Poland, Lithuania, Latvia, Estonia, Belarus and Finland. Data on space and time co-ordinates and dynamic parameters of these earthquake foci available from international centers and various seismological groups are analyzed. A degree of reliability of the results obtained is discussed. The epicentral zone of the Kaliningrad earthquakes is found within the western part of the old East European Platform (EEP). The seismotectonic map presenting the territories of Belarus and the Baltic States was considered, and the Kaliningrad-Lithuanian potential seismogenic area was analyzed. Methods used to outline possible earthquake zones when seismic zoning of the Belarusian-Baltic region was carried out were verified in practice and, actually, made possible a long-term forecast of earthquake origination in Kaliningrad.
Authors:T. Kaljuvee, M. Toom, A. Trikkel, and R. Kuusik
The extensive use of fossil fuels in energy production causes serious
pollution of atmosphere with SO2, CO2,
NOx, etc. In Estonia the electricity production is
based mainly on the pulverized firing (PF) of low-grade local fuel –
Estonian oil shale (EOS) which is characterized by a low calorific value (~9
MJ kg–1) and a high content of mineral matter
(65–70%) from which approximately 50% are carbonates. Since 2004, also
two boilers based on circulating fluidized bed combustion (CFBC) of EOS are
The present study is focused on the comparative
investigation of the efficiency of different ashes collected from different
technological points of CFB and PF boilers as sorbents for SO2.
The influence of experimental temperature on the SO2-binding
characteristics of ashes as well as the possibilities of activation of ashes
(grinding, hydration) were investigated. It was shown that the SO2-binding
capacity of initial ashes at 700C and p(SO2)=190
mm Hg was for CFBC ashes 24–30 mg and for PF ashes 10–23 mg SO2
per 100 mg sample, the best binding capacities belonging to economizer ash
(ECOA) and electrostatic precipitator ash from the 1st field (PESPA1f), respectively.
However, during initial stage of binding the best results were obtained with
air pre-heater ash (PHAA) and ESPA1f (both CFBC ashes). Grinding improved
the SO2-binding ability, being the most effective in
the case of bottom ash (BA) from CFBC and cyclone ash (PCA) from PF –
increase in binding capacity 2 and 2.3 times, respectively. As compared to
initial CFBC ashes, the binding characteristics of PF ashes remained lower
even after grinding. Hydration and previous calcination improved the binding
characteristics only of PF ashes. Hereby, the SO2-binding
ability of CFBC ashes is better than of PF ashes and they are more promising
sorbents for acidic gases, for example, for sulphur dioxide.
proposal for Estonia. Europe and Estonian Health Insurance Fund, WHO, 2008.
Groene, O., Kristensen, S., Arah, O. A., et al.: Feasibility of
Approximately one million tons of semicoke (SC) is formed and stored in open air dumps every year in the production of shale
oil by processing Estonian oil shale (OS). The content of different harmful compounds as sulphides, PAH, phenols, etc. in
SC make these dumps one of the most serious sources of environmental contamination. The aim of this work was to study the
behaviour of sulphur compounds in OS and its SC, formation of SO2 and possibilities of binding it into the solid phase during thermooxidation of fuel blends based on SC. Blends modified with
SC ash addition were studied as well. It was determined that SO2 emission in thermooxidation of SC samples started at 280-300C and proceeded with a steady speed up to 580-600C and the
amount of sulphur evolved was 5-10% from the total content of sulphur in the sample. The amount of SO2 emitted decreased depending on the mass ratio of the composite fuels from 49-56 to 15-35% during thermooxidation of OS samples
studied or their blends with SC, respectively, from 43-80% for coal samples to 13-60% for their blends with SC and to 2-13%
during thermooxidation of these blends modified with SC ash addition. In the products of thermooxidation formed at 800-900C
the only sulphur containing phase was CaSO4, at 650C also traces of CaS and CaMg3(SO4)4 were fixed.
Authors:T. Kaljuvee, A. Trikkel, R. Kuusik, and V. Bender
Summary The results of investigation of MgO participation in the binding of SO2 with lime-containing materials as sorbents are presented. Experiments of SO2 binding into solid phase using model samples of reactive grade MgO and CaO varying the mole ratio of MgO/CaO from 9:1 to 1:9 were carried out. Besides, dolomite and limestone samples with different MgO/CaO mole ratio (from 1.24 to 0.13) and samples of ashes formed at combustion of Estonian oil shale (containing 35-40% of carbonates) and its semicoke were studied Initial samples, intermediate and final products were subjected to chemical, IR-spectroscopy, X-ray and BET specific surface area analyses. The results of the present study confirmed the active participation of MgO in the binding of SO2 into the solid phase. In addition to CaSO4 the formation of Ca,Mg-double sulphate CaMg3(SO4)4 and ß-MgSO4 was observed. The presence of CaMg3(SO4)4 was fixed in a large temperature range 400-900°C and that of ß-MgSO4 in between 500-700°C. The optimum temperature range for formation and durability of CaMg3(SO4)4 was 700-800°C.
Authors:I. Rudjak, T. Kaljuvee, A. Trikkel, and V. Mikli
The thermal behaviour of ammonium nitrate (AN) and its prills coated with limestone and dolomite powder was studied on the
basis of commercial fertilizer-grade AN and six Estonian limestone and dolomite samples. Coating of AN prills was carried
out on a plate granulator and a saturated solution of AN was used as a binding agent. The mass of AN prills and coating material
was calculated based on the mole ratio of AN/(CaO + MgO) = 2:1. Thermal behaviour of AN and its coated prills was studied
using combined TG-DTA-FTIR equipment. The experiments were carried out under dynamic heating conditions up to 900 °C at the
heating rate of 10 °C min−1 and for calculation of kinetic parameters, additionally, at 2, 5 and 20 °C min−1 in a stream of dry air. A model-free kinetic analysis approach based on the differential isoconversional method of Friedman
was used to calculate the kinetic parameters. The results of TG-DTA-FTIR analyses and the variation of the value of activation
energy E along the reaction progress α indicate the complex character of the decomposition of neat AN as well as of the interactions
occurring at thermal treatment of AN prills coated with limestone and dolomite powder.
Authors:K. Siimer, T. Kaljuvee, P. Christjanson, T. Pehk, and I. Saks
Thermal behaviour of cure-accelerated phenol-formaldehyde (PF) resins was studied using the addition of commercial mixture
of water soluble oil shale alkylresorcinols (AR) to PF resin, 5-MR being as model compound. The acceleration effect of AR
is based on the promotion of condensation of resin methylol groups and subsequent reaction of released formaldehyde with AR.
Commercial PF resins SFŽ-3013VL and SFŽ-3014 from the Estonian factory VKG Resins have been used. The chemical structure of
resins was characterised by 13C NMR spectroscopy. TG-DTA analysis was carried out using labsysTM instrument Setaram. By TG-DTA measurements, the shift of exothermic and endothermic peaks and the changes of mass loss rate
in the ranges of 1.5–10 g AR/100 g PF resin were studied. The effect of AR on the curing behaviour of PF resins was also followed
by gel time.
Testing of the plywood when using PF resin with 5 mass% of AR shows that the press time could be reduced by about 15%.
Authors:Ф. Савихин, A. Kasikov, and Е. Васильченко
In this paper, changes in the number of inhabitants in Estonia as well as the Russians in the villages on the western coast of Lake Chudskoe (Western Prichudye) in the period from the end of the 16th to the end of the 19th centuries have been traced. The data obtained from the inspections, lists of Lutheran parishes, the estimations, the analysis of toponymy of 16th century and dialect peculiarities of the Russians of Western Prichudye made it possible to conclude that the main body of Russian population of the coastal villages were the descendants of Russians that had lived in the Northern and Western Prichudye long before the split of the Orthodox Church in Russia took place. As it is read in the reports to the Governor General in the 19th century, the Old Belief without the priest spread over Prichudye due to vigorous activity of Feodosii Vasiliev adepts among local Russians, and not as a result of the resettlement of a considerable number of Old Believers from Russia as it was supposed earlier. The assumption is made that the origin of the word
used by western Finns to call the Russians is a derivative from the word
Ammonium nitrate (AN) is one of the main nitrogen fertilizers used in fertilization programs. However, AN has some serious
disadvantages — being well soluble in water hardly 50% of the N-species contained are assimilated by plants. The second disadvantage
of AN is associated with its explosive properties. The aim of this paper was to clarify the influence of different lime-containing
substances — mainly Estonian limestone and dolomite — as internal additives on thermal behaviour of AN.
Commercial fertilizer grade AN was under investigation. The amount of additives used was 5, 10 or 20 mass%, or calculated
on the mole ratio of AN/(CaO, MgO)=2:1 in the blends. Experiments were carried out under dynamic heating condition up to 900°C
(10°C min−1) in a stream of dry air or N2 by using Setaram Labsys 2000 equipment coupled to Fourier transform infrared spectrometer (FTIR).
The results of analyses of the gaseous compounds evolved at thermal treatment of neat AN indicated some differences in the
decomposition of AN in air or in N2. At the thermal treatment of AN’s blends with CaCO3, MgCO3, limestone and dolomite samples the decomposition of AN proceeds through a completely different mechanism — depending on
the origin and the content of additives, partially or completely, through the formation of Mg(NO3)2 and Ca(NO3)2.
Authors:Viive Herne, A. Nelovkov, M. Kütt, and M. Ivanova
Rapid and reliable identification of pathogens is very important in the management of septic patients. We retrospectively evaluated the diagnostic accuracy and clinical utility of a multiplex real-time polymerase chain reaction (PCR) assay (SeptiFast (SF)) in patients with suspected sepsis in a tertiary care hospital in Tallinn, Estonia. A total of 160 blood samples from 144 patients were included in the study. SF results were compared with corresponding blood culture (BC) results. The concordance between SF and BC was 78.8%. The rate of positive results was significantly higher in SF than in BC (33.7% vs. 21.2%, respectively; p < 0.001). A total of 27 samples were found positive by both SF and BC, 27 by SF only, and seven by BC only. Of a total of 83 microorganisms detected SF identified 71, and BC 42 (p < 0.001). SF detected markedly more patients with candidemia: 11 patients were detected by SF compared to four patients by BC. Antimicrobial treatment was changed in 21 (38.9%) of 54 SF positive cases. In conclusion, our results demonstrated the high diagnostic accuracy of SF in detection of sepsis pathogens. In conjunction with its impact on therapeutic decisions, SF proved to be a useful adjunct to conventional blood culture in the diagnosis of sepsis etiology.