Seasonal variation of 7Be deposition in Japan

Seasonal variations of ⁷Be deposition in regions throughout Japan (26°18'N-43°05'N, 127°54'E-141°27'E) were observed during the period of 1989-1995. The observation indicated that ⁷Be deposition peaked in spring all over Japan except in the inland central basin. However, spring peak was not always the annual maximum. Along the coastal side of the Japan Sea, especially around Hokuriku region, ⁷Be deposition was at its maximum in winter. In addition, September peak also was observed in some regions, which was presumably caused by high precipitation or blowing in of northern air stream. Variations were classified into 4 types according to meteorological factors and local geographical conditions: winter peak, double peaks (spring and September peaks), spring peak and non-peak. A correlation between ⁷Be deposition and precipitation was observed in winter.     

Multi-experimental characterization of selected medical plants growing in the Czech Republic

Complex analysis of the impact of post-production conditions on antioxidant status, content of selected polyphenols, color, and concentration of selected metals was evaluated in the group of ten most popular medical plants conventionally produced in the Czech Republic. Ultraviolet visible near infrared spectroscopy (UV–VIS–NIR), electron paramagnetic resonance (EPR), high-performance liquid chromatography (HPLC), and inductively coupled plasma optical emission spectrometry (ICP-OES) were employed for these purposes. The entire data set of the obtained experimental characteristics was processed by multivariate statistical methods to assess the influence of the way of processing on sample properties. On the basis of 11 characteristics identified by the analysis of variance (ANOVA) as the most significantly different, successful differentiation of medical plant samples was achieved according to post-harvest treatment, families, and individual medical plant species by means of canonical discrimination method, reaching 100, 89.5, and 100% correctness, respectively. The importance of the sample processing on their properties and on the concentration of target naturally containing compounds with health-promoting and antioxidant properties was thus proved unambiguously.     

Comparison of activity measurements in nuclear medicine services in the Czech Republic

Radionuclide calibrator used in nuclear medicine is the radiation detection equipment for measuring radiopharmaceutical activity. This instrument consists of an ionization chamber with an electrometer. This paper examines the variation in the amounts of radioactivity that is associated with dose calibration. The amount of radioactivity in each sample was measured by CMI and compared with values obtained from radionuclide calibrators over a year period. Measurements of serum bottles were within 10 % for ¹⁸F and ⁹⁰Y, 10–15 % for ¹³¹I and ⁵¹Cr, 10–20 % for ^99mTc, 15–20 % for ⁶⁷Ga, 10–25 % for ¹¹¹In, 15–30 % for ²⁰¹Tl and 15–45 % for ¹²³I.     

Thermal parameters of roofing slates from Czech Republic

Thermal performance of building materials is an important parameter from the point of view of energy consumption for heating buildings, which is obviously related to environmental protection standards. Thermal parameters of roofing slates were measured for samples from two different formations in the Czech Republic. These were rocks of lower Carboniferous Culm facies of Moravice Formation and Silesian Unit of Flysch Moravian-Silesian Carpathians. Thermal conductivity and thermal effusivity measurements were performed with use of TCi analyser. Thermal parameters were obtained in parallel and perpendicular direction to the bedding in rocks. Thermal conductivity of the Moravian slates in the direction perpendicular to the bedding ranges from 1.43 to 1.79 W m^?1 K^?1, while for samples from Carpathian region this parameter ranges from 1.99 to 3.15 W m^?1 K^?1. High values of thermal conductivity correlate to higher quartz content in the rocks. The measured thermal parameters (conductivity, effusivity, diffusivity) are strongly depending on the direction of measurement. Thermal conductivity of analysed rocks increases along with increase in temperature. The increase in thermal conductivity value is more significant in case of Moravian slates. In practice, the obtained results indicate that the traditional building material, such as roofing slates, shows better insulation properties at lower temperatures, while in conditions of strong sunlight the temperature conductivity increases. In case of roofing slates, which tend to be highly anisotropic, the essential information is the direction of thermal parameters measurement. Slates, due to their specific texture, are characterized by a very high thermal anisotropy coefficient.

     

Natural science university education in Czech Republic and in Russia

In this article the author’s experience of university studies in the field of natural science in Russia and Czech Republic is summarized and analyzed.     

Determination of low-level tritium concentrations in surface water and precipitation in the Czech Republic

Past tests of nuclear weapons in the atmosphere, nuclear energy facilities and tritium of natural origin are main sources of tritium in the environment. Thanks to its presence in environment and its favourable properties, tritium is used as a radiotracer. Since stopping of atmospheric nuclear tests, tritium in precipitation has been decreasing towards natural levels below 1 Bq l^?1 and precise analyses of low level tritium activities are necessary. This paper focuses on tritium development at sites not influenced by any technogenic release of tritium in Elbe River basin (Bohemia) in the Czech Republic using liquid scintillation measurement with electrolytic enrichment.     

Investigation of7Be in the Bratislava atmosphere

Near-surface air concentrations of⁷Be and its deposition rates were measured in the atmosphere in Bratislava from 1977 to 1994. Late spring and summer maxima were observed in the near-surface air concentrations on an annual basis. Using measured deposition rates and the calculated average tropospheric content of⁷Be atoms, their mean tropospheric residence time (27–48 days) was determined. An anticorrelation between the measured⁷Be concentration and the sunspot number with correlation factor of 0.55 was observed.     

Total deposition velocities and scavenging ratios of 7Be and 210Pb at Rokkasho, Japan

The atmospheric concentrations and deposition fluxes of ⁷Be and ²¹⁰Pb were observed biweekly in Rokkasho, Japan on the Pacific Ocean coast at the northern end of Honshu Island, from March 2000 to March 2006, to clarify their regional features. Seasonal variation pattern of atmospheric ⁷Be concentrations had double peaks, and that of ²¹⁰Pb had a single peak. Deposition fluxes of ⁷Be and ²¹⁰Pb showed the same patterns. The total deposition pattern of ⁷Be was similar to that commonly seen on the Pacific Ocean side of northern Honshu Island, while the pattern of ²¹⁰Pb was similar to that commonly seen on the Japan Sea side. The lack of high spine mountains windward in Rokkasho may be the cause of this ambiguity in the winter monsoon season. Total deposition velocities and scavenging ratios of ²¹⁰Pb were similar to those of ⁷Be from spring to fall, and showed that both nuclides had a similar removal process from the atmosphere. However, the scavenging ratios of ²¹⁰Pb were slightly larger than those of ⁷Be in winter, indicating different behaviors for both nuclides in the scavenging process. The scavenging ratios of both nuclides inversely correlated with precipitation rate, and the ratios in winter were larger than in the other seasons.     

Seasonal variations of atmospheric210Pb and7Be concentrations at Kumamoto, Japan and their removal from the atmosphere as wet and dry depositions</p> </p>

Summary A relatively simple chemical separation procedure has been developed for the simultaneous determination of⁸⁹Sr and ⁹ 0Sractivities in water samples and on aerosol-filters of the Nuclear Power Plant (NPP) Paks origin. The procedure combines the cation-exchange chromatographic (Dowex 50 WX 8 resin) and solid phase extraction (EIChroM Sr.Spec?, DC18C6 crown ether) steps. The beta-radiation of radionuclides can be measured directly after the chemical separation by LSC. The activities of⁸⁹Sr,⁹⁰Sr and⁹⁰Y are calculated from an over determined set of equations using a method of constrained optimization technique. The equations are based on LSC measurements performed in three counting windows plus the⁹⁰Sr-⁹⁰Y decay law. The chemical yield of strontium is determined by ICP-AES. The lowest limits of detectable activity, for the measurement time of 600 minutes, are 30 mBq/sample and 18 mBq/sample for⁸⁹Sr and⁹⁰Sr, respectively.     

Atmospheric deposition of 7Be, 210Pb in Xining,a typical city on the Qinghai-Tibet Plateau,China

Journal of Radioanalytical and Nuclear Chemistry - First continuous observations of 7Be and 210Pb monthly total depositional fluxes were performed from December 2014 to November 2017 in Xining, a...     

Fallout of7Be in Damascus City

Atmospheric fallout of⁷Be was measured over a 2 year period (January 1995–January 1997) at Damascus city (33 N^o, 727 m above sea level). The annual total deposition of⁷Be was found to be 420 and 634 Bq·m⁻² for 1995 and 1996, respectively, reflecting a Mediterranean climate where two well recognized periods are dominant (wet and dry). The depositions in the wet periods were 303 Bq·m⁻² and 517 Bq·m⁻² for 1995 and 1996, respectively, while unexpected equal deposition rates in the two dry periods were found to be about 117 Bq·m⁻². In addition, monthly deposition rate of⁷Be showed a maxima in February in 1995 and January for 1996. Moreover, a comparison has been set for our measurements and other data obtained at different locations in the world.     

Determination of total nitrogen in atmospheric wet and dry deposition samples

A microwave-assisted persulfate oxidation method followed by ion chromatographic determination of nitrate was developed for total nitrogen determination in atmospheric wet and dry deposition samples. Various operating parameters such as oxidation reagent concentrations, microwave power, and extraction time were optimized to maximize the conversion of total nitrogen to nitrate for subsequent chemical analysis. Under optimized conditions, 0.012 M K₂S₂O₈ and 0.024 M NaOH were found to be necessary for complete digestion of wet and dry deposition samples at 400 W for 7 min using microwave. The optimized extraction method was then validated by testing different forms of organic nitrogen loaded to pre-baked filter substrates and NIST SRM 1648 (urban particulate matter), and satisfactory results were obtained. In the case of wet deposition samples, standard addition experiments were performed. The suitability of the method for real-world application was assessed by analyzing a number of wet and dry deposition samples collected in Singapore during the period of March-April 2007. The organic nitrogen content was 15% (wet) and 30% (dry) of the total nitrogen. During the study period, the estimated wet fluxes for nitrate (NO₃⁻), ammonium (NH₄⁺), organic nitrogen (ON), and total nitrogen (TN) were 16.1 ± 6.5 kg ha⁻¹ year⁻¹, 11.5 ± 5.7 kg ha⁻¹ year⁻¹, 3.8 ± 1.5 kg ha⁻¹ year⁻¹and 31.5 ± 13.2 kg ha⁻¹ year⁻¹, respectively, while the dry fluxes were 2.5 ± 0.8 kg ha⁻¹ year⁻¹, 1.4 ± 0.9 kg ha⁻¹ year⁻¹, 2.3 ± 1.4 kg ha⁻¹ year⁻¹ and 7.5 ± 2.6 kg ha⁻¹ year⁻¹, respectively.     

Improvement, quality assurance and analytical results on the river Elbe contamination in the Czech Republic

Environmental analysis at trace levels is a new field of research in the Czech Republic since about ten years. New methods have to be adapted, pollution sources have to be investigated and quality assurance has to be established. The improvement in the detemination of trace substances in the Elbe river, mainly that of organic pollutants, is shown. A first insight on an international level is given into the origin of pollution in the Czech part of the Elbe river and the analytical work provided by the Czech water research institute and one of the most important monitoring laboratories.     

Mechanism of 7Be scavenging from the atmosphere through precipitation in relation to seasonal variations in Rokkasho Village, Aomori Prefecture, Japan

⁷Be deposition fluxes and atmospheric concentrations were measured at Rokkasho Village, Aomori Prefecture, Japan, from 2000 to 2005. It was confirmed that the ⁷Be deposition fluxes were minimum in summer, and the fallout maximizes in winter. The atmospheric concentration of ⁷Be was especially low in summer, and high in the other three seasons. A positive correlation was observed between the amount of precipitation and ⁷Be deposition. Clear seasonal differences were evident among the ratios of ⁷Be deposition flux to precipitation amounts in the four seasons. The ratios were especially high in winter, higher than those in the other three seasons. ⁷Be deposition flux was estimated by a simple simulation model using atmospheric ⁷Be concentrations and local meteorological data. As a result, the estimated deposition value was relatively lower than the measured value in winter.     

Environmental analysis in the Czech Republic: organisation of proficiency testing and its use in laboratory assessment

The history, origin, and development of a system for monitoring and assessing water and other environmental laboratories in the Czech Republic is described. The system started in 1991 and has matured to its present complexity with similarities to the accreditation systems found in other countries. Differences from internationally recognized procedures are being corrected step by step. During the first year of its existence ASLAB, as part of its brief, organised proficiency testing (PT) programs for fifty laboratories. Today the total number of regularly participating laboratories exceeds 700 from the Czech Republic, the Slovak Republic, and Germany. This paper describes the ASLAB PT system, discusses some experiences with its use, and describes the use of PT results in assessment of the competence of laboratories. Received: 12 October 2000 Accepted: 7 January 2001