Wyniki wyszukiwania - BazTech

1

Prof. Alicja Dorabialska 1897-1975. „Pozostawię Wam w testamencie płomień mojego optymizmu”...

Bem H.

Eliksir

|

2015

|

nr 2

5--8

2

Zespół Radiochemii: powstawanie zespołu

Reimschussel W., Bem H.

Zeszyty Historyczne Politechniki Łódzkiej

|

2013

|

Z. 14

57--70

3

Osłony elastomerowe redukujące dawki promieniowania X w technikach tomografii komputerowe

Kusiak E., Zaborski M., Staniszewska A., Bem H., Szajerski P., Baryń W.

Polimery

|

2013

|

T. 58, nr 7-8

519--523

PL

Opracowano bezołowiowe osłony redukujące dawki promieniowania w diagnostyce technikami tomografii komputerowej. Podstawę stanowiła matryca z kauczuku naturalnego napełnionego tlenkami: bizmutu, wolframu lub gadolinu. Ze względu na generowanie przez bizmut wtórnego promieniowania fluorescencyjnego rozszerzono pierwotne składy kompozytów. Stwierdzono, że otrzymane kompozyty kauczuku naturalnego zawierające kombinacje tlenków metali charakteryzowały się dużymi wartościami masowych współczynników pochłaniania, wpływały na redukcję natężenia promieniowania padającego o energii: Eg = 60 keV o ok. 50 % a o energii Eg = 122 keV o ok. 20 %. Jednocześnie prawie wszystkie próbki wulkanizatów wykazywały korzystne właściwości wytrzymałościowe.

EN

We have developed lead-free shields reducing the radiation doses in the diagnostic computed tomography techniques. They are based on natural rubber matrix with oxides of bismuth, tungsten and gadolinium as fillers. Due to the generation of secondary fluorescence radiation by bismuth, the study was extended to other compositions. The obtained natural rubber composites containing the combinations of metal oxides were characterized by high values of the mass absorption coefficient, which effected in the reduction in the intensity of incident radiation with an energy Eg = 60 keV by about 50 % and for Eg = 122 keV by about 20 %. It should be noted that virtually all vulcanizates showed good strength properties.

4

Elastomery zawierające związki bizmutu chroniące przed promieniowaniem X

Kusiak E., Zaborski M., Bem H., Baryń W.

Przemysł Chemiczny

|

2010

|

T. 89, nr 4

454-456

5

A comparison of selected natural radionuclide concentrations in the thermal groundwater of Mszczonów and Cieplice with deep well water from Łódź city, Poland

Grabowski P., Długosz M., Szajerski P., Bem H.

Nukleonika

|

2010

|

Vol. 55, No. 2

181-185

EN

A simple procedure using α and γ spectrometry for the determination of natural radionuclides in two Polish geothermal water samples from Mszczonów and Cieplice, as well as in deep well groundwater from the city of Łódź, was described. The 222Rn radionuclide was directly extracted from 10 cm3 water samples to a scintillator solution placed in scintillation vials and determined by an liquid scintillation (LSC) technique with α/β separation. The activity concentrations of three radium nuclides: 228Ra(228Ac), 226Ra(222Rn), 224Ra, as well as 210Pb and 228Th were measured by γ spectrometry with an HPGe detector after their preconcentration on hydrated MnO2. 210Po was deposited on a silver disc from dissolved MnO2 precipitate after γ-spectrometry analysis and measured by α spectrometry. The concentration of 210Pb in the examined samples was below the detection limit of the method (< 6.2 mBq/dm3), whereas activity of its decay product 210Po was in the range 0.35–1.4 mBq/dm3. Higher activities of 228Ra (46.7 mBq/dm3), 226Ra (67.8 mBq/dm3) and 224Ra (22.4 mBq/dm3) were observed for the deep well water in Łódź in comparison to those for geothermal water samples from Cieplice and Mszczonów. However, concentrations of all the measured radionuclides were below World Health Organization (WHO) reference activities (0.1 Bq/dm3 for 228Ra and 1 Bq/dm3 for 226Ra and 226Ra).

6

Technologically enhanced naturally occurring radioactive materials in the oil industry (TENORM).

Bou-Rabee F., Al-Zamel A. Z., Al-Fares R. A., Bem H.

Nukleonika

|

2009

|

Vol. 54, No. 1

3-9

EN

A large amount of naturally occurring radioactive materials in the form of by-products or waste is produced annually by the growing activity of the oil and gas industry. Solid scale, sludge and produced water are typical residues contaminated with natural radionuclides from the uranium and thorium series, particularly 226Ra and 228Ra. The observed specific activities of these radionuclides are in the ranges up to 3700 kBq/kg and up to 168 kBq/kg for solid scale and sludge, respectively. The average activities of both radionuclides exceed the exemption level of 10,000 Bq/kg recommended by IAEA safety standards. This means that TENORM wastes from the oil industry may generate radiation exposure levels which require attention and continuous monitoring during some routine operations in this industry. This exposure is mostly caused by external gamma radiation coming from the 226Ra radionuclide and its progenies.

7

Naturalne radionuklidy w surowcach, półproduktach i płytkach ceramicznych

Długosz M., Bem H.

Materiały Ceramiczne

|

2008

|

T. 60, nr 4

164-167

PL

W pracy przedstawiono wyniki analizy naturalnej promieniotwórczości surowców, półproduktów i gotowych produktów ceramicznych wyrabianych na terenie Polski. Surowce stosowane w przemyśle ceramicznym zawierają naturalne radionuklidy, których aktywność niekiedy przekracza średnie ich poziomy w glebie [1]. Zgodnie z Rozporządzeniem Rady Ministrów z dnia 2 stycznia 2007 [2] do oceny przydatności materiałów budowlanych wykorzystuje się tzw. współczynniki f1 i f2. Do analizy wykorzystano nie niszczącą metodę spektrometrii gamma (z detektorem HPGe). Najwyższe stężenia naturalnych radionuklidów zaobserwowano dla skalenia i glin (najniższe zaś dla piasku kwarcowego). Gotowe do zastosowania produkty z większym udziałem skalenia i glin wykazują wyższe wartości zarówno współczynnika f1 jak i f2. Otrzymane wartości współczynnika f1 od 0,06 do 1,36 natomiast dla f2 od 8,6 do 379,3 Bq/kg. Dla porównania załączono wyniki analiz płytki importowanej, w której zaobserwowano znacznie wyższe wartości współczynników f1 i f2. Analizy płytek krajowych potwierdzają, możliwość stosowania ich jako materiały wykończeniowe na zewnątrz i wewnątrz budynków.

EN

The natural radionuclides originated from uranium and thorium series as well potassium isotope 40K occur in raw materials used for production of different ceramic items. According to the Polish law the radioactivity of all building materials should comply with limits for the total activity determined by so called coefficient f1, as well as of 226Ra should be below the value 200 Bq/kg (so called f2-coefficant). In practice, some mineral components used in ceramic industry may contain the nature activities remarkably higher than those observed in surface soil. In this work, an analysis of natural radionuclides in some raw materials is presented by-products and commercially available products in Poland. Concentration of the most important radionuclides: 40K, 228Th, 226Ra and 210Pb was detected by gamma-ray spectrometry method and HPGe detector. The observed values of f1, coefficient ranged from 0.06 to 1.36 and from 8.6 to 379,3 Bq/kg for f2. The highest activity concentrations have been observed for the feldspar and some clay samples, while the Iowest values were typical for the quartz sand samples.

8

Determination of the sediment deposition rates in the Kuwait Bay using 137Cs and 210Pb

Al-Zamel A., Bou-Rabee F., Al-Sarawi M., Olszewski M., Bem H.

Nukleonika

|

2006

|

Vol. 51,suppl.2

39-44

EN

Five bottom sediment cores from the Kuwait Bay were dated using 210Pb and 137Cs radionuclides. For evaluating the sedimentation rate two methods were applied: geochronology with the constant rate of supply unsupported 210Pb (CRS model) and the Weibull distribution of anthropogenic 137Cs. The sedimentation rates in this region, calculated by the first method ranged from 0.24 to 0.39 cm/year, while the same rates obtained from 137Cs distribution were slightly lower: from 0.1 to 0.25 cm/year. These relatively small differences can be explained by additional input of the Chernobyl accident to the 137Cs inventory in the bottoms sediments of the Northern Hemisphere.

9

Determination of radium 226Ra nuclide in ground-level air

Bem H., Olszewski M.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

|

2004

|

nr 1

95-96

10

A protocol for determination of natural radionuclides in the geothermal water

Bem H., Olszewski M., Kaczmarek A.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

|

2004

|

nr 1

94-95

11

Evaluation of the coal combustion input to the 226Ra ground-level air concentration in the Lodz city, Poland

Bem H., Olszewski M., Bysiek M., Gluba T.

Nukleonika

|

2004

|

Vol. 49, nr 4

167-171

EN

The network of high volume aerosol samplers type ASS-500 in Poland, established mainly for monitoring radionuclides of artificial origin, offers also a unique opportunity for measuring natural radionuclide concentrations in ground-level air. Recounting of the closed (sealed) filters after a one month period, necessary for establishing radioactive equilibrium between 226Ra and 222Rn, as well as its short-lived decay products, remarkably improves the accuracy of 226Ra determination. The Currie's average detection and determination limits (with 10% relative accuracy) calculated for 226Ra for 160,000 s counting time and combined with the average filtered air volume of 60,000 m3 were 0.3 and 1.2 mi Bq/m3, respectively. The observed 226Ra concentrations in air in Lodz during the half year collection period, including parts of winter and summer seasons, were always above the detection limit and ranged from 0.76 to 2.75 mi Bq/m3. 226Ra, present in the ground level air mainly as a result of resuspension from the top layer of soil and fly ash emissions from coal burning, was used for rough estimation of the contribution of the coal combustion to the total suspended particulate matter. On the basis of available data for 226Ra content in the soil and fly ashes for the Lodz region of Poland, the calculated coal combustion input to the total air suspended particulate matter ranged from 8 to 39%.

12

Concentration of selected natural radionuclides in the thermal groundwater of Uniejów, Poland

Bem H., Olszewski M., Kaczmarek A.

Nukleonika

|

2004

|

Vol. 49, nr 1

1-5

EN

Activities of the main radionuclides from the 238U and 232Th series in the Uniejów geothermal water were determined by combining liquid scintillation counting with a/b separation and g-spectrometry methods. The 222Rn and 226Ra activities were measured after extraction of radon from 10 ml water samples to 10 ml of an Ultima Gold F scintillation cocktail directly in 22 ml scintillation vials. The samples were counted in a new generation portable liquid scintillation counter, Betascout, without separation of the phases over the period of 30 days after extraction. The average values of the specific activities were equal to 2.95 and 0.64 Bq/dm3 for 222Rn and 226Ra, respectively. The 210Po radionuclide before counting was preconcentrated from 1 dm3 water samples on hydrated manganese oxide and deposited on silver discs. The discs were immersed in 10 ml of the scintillator and their activity was measured also by the same method. The average 210Po concentration was 0.052 Bq/dm3. Activity of the remaining radionuclides was determined by g-spectrometry after their preconcentration on hydrated manganese oxides from 10 dm3 samples. The activities of two radium radionuclides, 224Ra and 226Ra, can be calculated from their basic gamma-lines, whereas 228Ra can be determined from its decay product - 228Ac, and were equal to 0.40, 0.65 and 0.58 Bq/dm3, respectively. The activities of 210Pb and 238U (234Th) were below the detection limit of the method equal to 0.03 Bq/dm3. Based upon the obtained results, it can be concluded that there are not any radiological restrictions for using this water as a heat source or for balneological purposes. However, it cannot be used as drinking water, because the calculated committed effective dose from its one year consumption exceeds the WHO recommended value of 0.1 mSv.

13

Determination of radioactivity in air filters by alpha and gamma spectrometry

Bem H., Bem E. M., Krzemińska M., Ostrowska M.

Nukleonika

|

2002

|

Vol. 47, nr 2

87-91

EN

Combination of alpha and gamma spectrometry for air filters measurement allows a simple determination of all short-lived 222Rn and 220Rn daughters as well as cosmogenic 7Be and anthropogenic 137Cs in the air. Solid radionuclides in the atmosphere, attached to aerosol particles, were collected on filters of High Volume Air Sampler. After the desired collection period, the activity of deposited radionuclides was measured by ă-spectrometry for 7Be, 212Pb, 212Bi, 214Pb, 214Bi and by á-spectrometry for 212Po, 214Po and 218Po. Spectrometric methods do not require additional sample preparation and allow one to find aerosol activity by a simple filter measurement. A special measurement and calculation procedure was applied in the case of radionuclides from the uranium and thorium series. A technique of liquid scintillation counting (LSC) was used to determine the activity of the long-lived radon daughters 210Pb, 210Bi, 210Po after leaching into HCl solution and a two-step pre-concentration. Simultaneous determination of 210Pb and 210Bi enables one to find aerosol residence times.

14

Comparison of two methods for (sup 226)Ra determination in mineral water

Bem H., Bem E. M., Majchrzak I.

Nukleonika

|

1998

|

Vol. 43, nr 4

459-468

EN

(sup 226) Ra concentration in bottled mineral water has been determined by a liquid scintillation technique (LSC) with the separation of α from β pulses. Extraction of radon from 0.5 dm3 of water samples to 20 ml of a xylene based scintillation cocktail is sufficient for the determination of (sup 226)Ra concentrations above12 mBq/dm3 (with ±10% error). A lower (sup 226)Ra concentration (from 2.2 mBq/dm3) can be measured after preliminary co-precipitation of (sup 226)Ra with calcium phosphate at pH = 10 from 1.5 dm3 water samples. The obtained precipitates were dissolved with HCL solution directly in the scintillation vials and then the xylene based scintillation cocktail was added. The activity was measured after reaching a (sup 226)Ra - (sup 222)Rn equilibrium and the removal of water. Where as the (sup 226)Ra determination limit for the simple extraction method is not sufficient for some mineral water samples, the second more laborious method can be applied for (sup 226)Ra determination even in tap waters. From the examined mineral water available on the local market only in one case did the (sup 226)Ra activity exceed the limit of 100 mBq/dm3 for the total α activity in the bottled mineral waters.

PL

Stężenie (sup 226)Ra w butelkowanych wodach mineralnych oznaczano techniką ciekłej scyntylacji z separacją impulsów α od β. Prosta ekstrakcja równowagowego (sup 222)Rn z próbek wody o objętości 0.5 dm3 do 20 mi scyntylatora ksylenowego pozwala na oznaczanie poziomów (sup 226)Ra wyższych od 12 mBq/dm3 (z błędem ±10%). Niższe stężenia (>2.2 mBq/dm3) można mierzyć po wstępnym zatężeniu (sup 226Ra) przez współstrącanie z fosforanem wapnia z próbki wody o objętości 1.5 dm3 przy pH = 10. Otrzymany osad rozpuszczano w stężonym HCI bezpośrednio w naczynkach scyntylacyjnych. Następnie dodawano do nich 10 mi scyntylatora ksylenowego. Aktywność (sup 222)Rn i produktów jego rozpadu mierzono po ustaleniu się równowagi (sup 226)Ra - (sup 222)Rn i usunięciu warstwy wodnej. Metoda ta pozwala oznaczyć zawartość 226Ra również w wodach otwartych oraz w wodzie wodociągowej. Tylko w jednej wodzie mineralnej stwierdzono przekroczenie dopuszczalnego limitu całkowitej aktywności a wynoszącego 100 mBq/dm3.