Wyniki wyszukiwania - BazTech

1

Radon and remediation measures near Băiţa-Ştei old uranium mine (Romania)

Cosma C., Cucoş A., Papp B., Begy R., Dicu T., Moldovan M., Truţă L., Niţă D., Burghele B., Suciu L., Sainz C.

Acta Geophysica

|

2013

|

Vol. 61, no. 4

859--875

EN

Băiţa-Ştei mine is an open pit mine in NW Romania (West Carpathian Mountains). It was the largest surface uranium deposit in the world. Two means of uranium transport and dissemination were used over time. The first was the natural way, represented by transportation of geological sediments by Crişul-Băiţa River that crosses the Băiţa surface deposit. These sediments were used as building materials (stone, gravel, sand). The second way was related to the people living in this valley, who used also the uranium waste as building material. The preliminary indoor radon concentrations measured in the buildings ranged from 40 to 4000 Bq m−3 with a mean value of 241 Bq m−3. A focused radon survey facilitated the selection of 20 houses with the highest indoor radon that were therefore proposed for remediation. To find the radon sources of these houses, systematic investigations on radon were performed. The remedial measures for these 20 houses were tested on a chosen pilot house.

2

A sedimentation study of St. Ana Lake (Romania) applying the 210 Pb and 137 Cs dating methods.

Begy R. C., Timar-Gabor A., Somlai J., Cosma C.

Geochronometria

|

2011

|

Vol. 38, no. 2

93-100

EN

The biggest problem with most lakes that have no contact with other water sources and are being charged by precipitation is the massive eutrophication. The aim of this work was to determine the sedimentation rate in order to evaluate the progress of eutrophication for St. Ana Lake (Ciomad Mountain near the Băile Tuşnad in Harghita County (Romania)). The concentration of 210 Pb was determined by means of high resolution gamma spectrometry as well as derived from 210 Po activity which was measured through alpha spectrometry; values obtained are in good agreement. For the excess 210 Pb activity values between 4.0š0.5 Bq/kg and 218š20 Bq/kg have been found. As an alternative method, the 137 Cs dating method was applied as well. Calculated mass sedimentation rates are in the range of 0.06š0.01 to 0.32š0.05 g/cm 2 year with a mean of value of 0.15š0.02 g/cm 2 year. Linear sedimentation rates yielded much higher sedimentation values (between 0.5š0.1 and 7.9š0.7 cm/year with a mean of 2.4š0.6 cm/year), due to the predominant organic matter composition and the long suspension time of the sediment. This is an indication for the process of eutrophication which will probably lead to the transformation of the lake into a peat bog.

3

A high resolution optical dating study of the Mostiştea loess-palaeosol sequence (SE Romania) using sand-sized quartz

Vasiliniuc S., Timar-Gabor A., Vandenberghe D. A. G., Panaiotu C. G., Begy R. CS., Cosma C.

Geochronometria

|

2011

|

Vol. 38, no. 1

34-41

EN

We report on SAR-OSL dating of closely-spaced samples from the loess-palaeosol sequence near Mostiştea lake (Danube Plain, SE Romania). We used sand-sized quartz and a SAR protocol that involved a preheat of 10s at 220°C and a test dose cutheat to 180°C. It is shown that these thermal pretreatments isolate a quartz OSL signal that is dominated by the fast component. The behavior of this signal in the SAR protocol is then documented. The ratio of the measured to given dose tends to lie slightly but systematically above unity (~5% on average) and the recycling ratio below unity (~6% on average); for all samples, the recuperated signal is negligible. Within analytical uncertainty, the nineteen optical ages are internally consistent and agree with the predictions from a palaeomagnetic age-depth model. Although it may be possible to optimize the SAR measurement procedure, the optical ages already confirm the chronostratigraphic position of the uppermost welldeveloped palaeosol in that it formed during MIS 5.The established chronology allows correlating the sequence near Mostiştea lake with that near Mircea Vodă that we investigated earlier.

4

Measurement of radon potential from soil using a special method of sampling

Cosma C., Papp B., Moldovan M., Cosma V., Cindea C., Cindea C., Suciu L., Apostu A.

Acta Geophysica

|

2010

|

Vol. 58, no. 5

947-956

EN

Soil radon gas and/or its exhalation rate are used as indicators for some applications, such as uranium exploration, indoor radon concentration, seismic activity, location of subsurface faults, etc., and also in the studies where the main interest is the field verification of radon transport models. This work proposes a versatile method for the soil radon sampling using a special manner of pumping. The soil gas is passed through a columnof charcoal by using passive pumping. A plastic bottle filled with water is coupled to an activated charcoal column and the flow of water through an adjustable hole made at the bottom of bottle assures a controlled gas flow from the soil. The results obtained for the activity of activated charcoal are in the range of 20-40 kBq/m3, for a depth of approximately 0.8 m. The results obtained by this method were confirmed by simultaneous measurements using LUK 3C device for soil radon measurements. Possible applications for the estimation of radon soil potential are discussed.

5

Genotoxic effects of 60Co gamma-rays on Chinese hamster ovary (CHO) cells

Dicu T., Brie I., Virag P., Fischer E., Perde M., Foriş V., Cernea V., Cosma C.

Nukleonika

|

2008

|

Vol. 53, No. 4

161-165

EN

The aim of the present study was to evaluate the cellular radiosensitivity and radiation-induced DNA damage and repair in Chinese hamster ovary (CHO) cells. Cell survival after irradiation was assessed using the clonogenic assay. The initial, radio-induced and residual DNA damage in Chinese hamster ovary (CHO) cells exposed to 60Co gamma-rays were determined using the alkaline comet assay. A linear-quadratic (LQ) survival curve was observed in CHO line. Data obtained by comet assay demonstrated a linear dose-response correlation in the range of tested doses (0.3-4 Gy). The process of DNA repair was modeled by exponential equation. In addition, we found a good correlation (R2 = 0.995) between clonogenic cell survival and radio-induced DNA damage.

6

Luminescence dating of neolithic ceramics from Lumea Nouă, Romania

Benea V., Vanderberghe D., Timar A., Van den Haute P., Cosma C., Gligor M., Florescu C.

Geochronometria

|

2007

|

Vol. 28

9-16

EN

Luminescence dating was applied to four Neolithic pottery fragments excavated at Lumea Nouă (Alba Iulia, Romania), with the purpose of improving the chronology for the archaeological finds, and hence, the occupational history of the site. The single-aliquot regenerative-dose (SAR) protocol was applied to both blue and infrared stimulated luminescence signals from coarse quartz and polymineral fine grains, respectively. A more conventional approach which uses a multiple-aliquot additive-dose protocol and thermoluminescence signals from polymineral fine grains was applied as well. The characteristics of the OSL and IRSL signals were investigated in terms of behaviour in the SAR protocol, dose response and dose recovery. Additionally, anomalous fading measurements of the 410 nm IRSL emission and of the blue TL emission from polymineral fine-grains were performed. Both signals were observed to be affected by anomalous fading. OSL dating of quartz using the SAR protocol is considered to be the technique of choice; it yields an average age of 6.0±0.4 ka (n = 4), which is in agreement with archaeological expectations. The dating results allow refining the typological interpretation of the objects and improve the chronological framework for the site.

7

Greases for food processing

Ortansa F., Cosma C., Constantinescu A. G.

Problemy Eksploatacji

|

1998

|

nr 3

101-111

PL

W przemyśle spożywczym używa się smarów do smarowania maszyn i urządzeń służących bezpośrednio do produkcji żywności, jak również opakowań. Smary muszą spełniać normy toksykologiczne wymagane przez międzynarodowe przepisy dotyczące przetwórstwa żywności. Zgodnie z tymi normami smary oznaczone kodem H1 używane są w przetwarzaniu żywności tam, gdzie istnieje możliwość przypadkowego kontaktu z żywnością, a smary H2 to te, które nie mają możliwości takiego bezpośredniego kontaktu. Składniki używane w tworzeniu obydwu kategorii smarów, takie jak oleje, zagęszczacze i dodatki muszą być substancjami nietoksycznymi. Jednocześnie smary używane w przemyśle spożywczym muszą spełniać wymagania techniczne i ekologiczne. Najbardziej odpowiednie są kompleksowe smary aluminiowe, dlatego są szeroko stosowane.

EN

Food industries require lubricating greases for equipment and machinery, which produce directly food as well as can-making equipment. Greases must fulfill the toxicological restrictions claimed by the international regulations concerning food processing. According to the restrictions, the greases identified as Code H1 are used in the food industry where there is a possibility of incidental food contact, and H2 greases are those where there is no possibility of contact. The components used in greases formulation of both categories such as oils, thickening agents, and additives, must be nontoxic substances. Simultaneously, the lubricants used in the food industry must satisfy the technical and ecological requirements. The Aluminium Complex Greases are the most suitable; therefore they are widely used.