scholarly journals Influence of Meteorological Parameters on the Variations of Atmospheric Radionuclides Concentration in Dar es Salaam, Tanzania

2020 ◽  
pp. 1-18
Author(s):  
Dorice Rashid Seif ◽  
Yusuf Ismail Koleleni
Keyword(s):  
Regression Analysis ◽  
Meteorological Parameters ◽  
Activity Concentration ◽  
Absolute Humidity ◽  
Dar Es Salaam ◽  
The Other ◽  
Atmospheric Conditions ◽  
Activity Concentrations ◽  
The Mean ◽  
Atmospheric Concentrations

Atmospheric concentrations of 7Be and 212Pb were measured for 11 years (2008 – 2018) in Dar es Salaam, Tanzania. The mean activity concentrations of 7Be and 212Pb were found to be within the range of 1.29 – 5.71 mBq/m3 and 10.85 – 50.06 mBq/m3, respectively. The annual mean activity concentrations of 7Be and 212Pb were 4.72 ± 1.18 mBq/m3 and 29.76 ± 13.63 mBq/m3, respectively. Distinct annual trends were depicted on 7Be and 212Pb, suggesting that the two radionuclides were affected differently with atmospheric conditions. Monthly atmospheric concentrations of 7Be showed a strong seasonal variation trend with the highest in January and February and lowest in April. 212Pb depicted the highest concentration during June and July and lowest in January and December. The regression analysis for 7Be and 212Pb activity concentrations together with number of meteorological parameters revealed that the relative humidity, rainfall, air temperature, absolute humidity and wind speed are the most significant parameters affecting radionuclides activity concentrations in the atmosphere. The sunspot numbers show 66.7% of its variability with 7Be activity concentration which further suggesting that other parameters may influence its variation. 212Pb, on the other hand, shows only 27.3% of its variability which clearly indicates that the existence of cosmic rays does not affect its activity concentration in the atmosphere.

scholarly journals 137Cs, 40K, and K in raw and stir-fried mushrooms from the Boletaceae family from the Midu region in Yunnan, Southwest China

2020 ◽  
Vol 27 (26) ◽  
pp. 32509-32517 ◽  
Author(s):  
Jerzy Falandysz ◽  
Ji Zhang ◽  
Michał Saniewski
Keyword(s):  
Southwest China ◽  
Activity Concentration ◽  
Geographical Origin ◽  
Weight Basis ◽  
Wild Mushrooms ◽  
Activity Concentrations ◽  
Wet Weight ◽  
The Mean ◽  
Loss Of Mass ◽  
Insight Into

Abstract The parallel batches of the same species and geographical origin mushrooms both raw and stir-fried were investigated to get an insight into the content and intake of 137Cs, 40K, and K from mushroom meals. The Boletaceae family species (Baorangia bicolor, Boletus bainiugan, Butyriboletus roseoflavus, Retiboletus griseus, Rugiboletus extremiorientalis, and Sutorius magnificus) were collected from the Midu County (Dali Bai Autonomous Prefecture) in 2018. The activity concentrations of 137Cs in the caps of dried raw mushrooms were in the range 14 ± 1 Bq kg−1 dry biomass (db) (R. griseus) to 34 ± 2 Bq kg−1 db (R. extremiorientalis), and in stems from 16 ± 1 Bq kg−1 db (B. bicolor and B. bainiugan) to 23 ± 1 Bq kg-1 db (R. extremiorientalis). The mean activity concentration in the whole fruiting bodies in all six species was 18 ± 4 Bq kg-1 db. The activity concentrations of 137Cs were roughly the same in both dehydrated materials, stir-fried, and raw mushrooms, while the contents of 40K and stable K were around 2- to 3-fold smaller in stir-fried than raw product. The raw and stir-fried mushrooms on a whole (wet) weight basis showed activity concentrations of 137Cs in the range from 1.2 to 3.2 Bq kg−1 ww (mean 1.9 ± 0.6 Bq kg−1 ww) and 6.0 to 9.4 Bq kg−1 ww (mean 7.0 ± 1.2 Bq kg−1 ww), respectively. Evidently, when expressed on a whole (wet) weight basis, the cooked mushrooms showed on average around 3.5-fold greater activity concentration of 137Cs when compared with raw mushrooms. The 137Cs, 40K, and total K enrichment in stir-frying (in a whole (wet) weight basis for the meal), confronted with the results for dehydrated raw and fried mushrooms, show the direct correlation with loss of mass (largely moisture) during the cooking procedure but not much of 137Cs and 40K. Edible wild mushrooms from Yunnan were little contaminated with radiocaesium. As assessed, the mean radioactivity dose from natural 40K in around 9.3-fold exceeded the dose obtained for artificial 137Cs from stir-fried mushroom meals, which both were very low doses.

Comparison of locations used in cotton-breeding trials

1992 ◽  
Vol 32 (6) ◽  
pp. 739 ◽  
Author(s):  
ER Williams ◽  
DJ Luckett ◽  
PE Reid ◽  
NJ Thomson
Keyword(s):  
Regression Analysis ◽  
The Other ◽  
Cultivar Differences ◽  
Yield Data ◽  
Cotton Breeding ◽  
Eastern Australia ◽  
Discrimination Criterion ◽  
The Mean ◽  
Joint Regression Analysis ◽  
The Stability

Cotton-breeding trials are conducted annually throughout the commercial growing regions of eastern Australia. Accumulated yield data for the period 1974-85 were assembled into an incomplete cultivar x location x year table. This table was then analysed in order to compare test locations. The method involved analysing cultivar x location tables separately for each year, using symmetric joint regression analysis. Results were then collected into location x year tables and further analysed. Four criteria for comparing test locations were developed. The discrimination criterion is important when locations are evaluated in terms of their ability to display cultivar differences. The representation criterion measures the ability of a location to mirror the relative performance of cultivars over all locations. The other 2 criteria are concerned with the mean yield at test locations and the stability of location yields over years. Based on the 4 criteria, preferred test locations are recommended.

scholarly journals Short-term <sup>222</sup>Rn activity concentration changes in underground spaces with limited air exchange with the atmosphere

2011 ◽  
Vol 11 (4) ◽  
pp. 1179-1188 ◽  
Author(s):  
L. Fijałkowska-Lichwa ◽  
T. A. Przylibski
Keyword(s):  
Mechanical Ventilation ◽  
Radiation Protection ◽  
Activity Concentration ◽  
Residential Buildings ◽  
Ventilation System ◽  
The Other ◽  
Uranium Mine ◽  
Activity Concentrations ◽  
Concentration Changes ◽  
Air Exchange

Abstract. The authors investigated short-time changes in 222Rn activity concentration occurring yearly in two underground tourist facilities with limited air exchange with the atmosphere. One of them is Niedźwiedzia (Bear) Cave in Kletno, Poland – a natural space equipped with locks ensuring isolation from the atmosphere. The other site is Fluorite Adit in Kletno, a section of a disused uranium mine. This adit is equipped with a mechanical ventilation system, operated periodically outside the opening times (at night). Both sites are situated within the same metamorphic rock complex, at similar altitudes, about 2 km apart. The measurements conducted revealed spring and autumn occurrence of convective air movements. In Bear Cave, this process causes a reduction in 222Rn activity concentration in the daytime, i.e. when tourists, guides and other staff are present in the cave. From the point of view of radiation protection, this is the best situation. For the rest of the year, daily concentrations of 222Rn activity in the cave are very stable. In Fluorite Adit, on the other hand, significant variations in daily 222Rn activity concentrations are recorded almost all year round. These changes are determined by the periods of activity and inactivity of mechanical ventilation. Unfortunately this is inactive in the daytime, which results in the highest values of 222Rn activity concentration at the times when tourists and staff are present in the adit. Slightly lower concentrations of radon in Fluorite Adit are recorded in the winter season, when convective air movements carry a substantial amount of radon out into the atmosphere. The incorrect usage of mechanical ventilation in Fluorite Adit results in the most unfavourable conditions in terms of radiation protection. The staff working in that facility are exposed practically throughout the year to the highest 222Rn activity concentrations, both at work (in the adit) and at home (outside their working hours). Therefore, not very well considered solution for the ventilation system not only does not prevent radioactive exposure of the staff, but can even increase it. The authors have also observed comparable characteristics of the annual patterns of 222Rn activity concentration changes in underground spaces and residential buildings situated in the same or similar climatic zones.

scholarly journals Development of Predictive Model for Radon-222 Estimation in the Atmosphere using Stepwise Regression and Grid Search Based-Random Forest Regression

2021 ◽  
pp. 132-139
Author(s):  
Omodele Olubi ◽  
Ebeneze Oniya ◽  
Taoreed Owolabi
Keyword(s):  
Random Forest ◽  
Stepwise Regression ◽  
Meteorological Parameters ◽  
Activity Concentration ◽  
Absolute Humidity ◽  
Grid Search ◽  
Random Forest Regression ◽  
Significant Interest ◽  
Polar Research Institute ◽  
Field Measuring

This work develops predictive models for estimating radon (222Rn) activity concentration in the atmosphere using novel grid search based random forest regression (GS-RFR) and stepwise regression (SWR). The developed models employ meteorological parameters which include the temperature, pressure, relative and absolute humidity, wind speed and wind direction as descriptors.  Experimental data of radon concentration and meteorological parameters from two observatories of the Korea Polar Research Institute in Antarctica (King Sejong and Jang Bogo) have been employed in this work.  The performance of the developed models was assessed using three different performance measuring parameters. On the basis of root mean square error (RMSE), the GS-RFR shows better performance over the SWR. An improvement of 64.09 % and 15.19 % was obtained on the training and test datasets, respectively at King Sejong station. At the Jang Bogo station, an improvement of 75.04 % and 28.04 % was obtained on the training and test datasets, respectively. The precision and robustness of the developed models would be of significant interest in determining the concentration of radon (222Rn) activity concentration in the atmosphere for various physical applications especially in regions where field measuring equipment for radon is not available or measurements have been interrupted.

scholarly journals The transfer of 137Cs through the soil-plant-sheep food chain in different pasture ecosystems

1996 ◽  
Vol 5 (6) ◽  
pp. 577-591
Author(s):  
Arja Paasikallio ◽  
Riitta Sormunen-Cristian
Keyword(s):  
Seasonal Variation ◽  
Food Chain ◽  
Activity Concentration ◽  
Clay Soil ◽  
The Other ◽  
Chernobyl Fallout ◽  
Transfer Factors ◽  
Natural Pasture ◽  
Plant Transfer ◽  
The Mean

A grazing experiment with sheep was carried out in 1990-1993 on natural, semi-natural and cultivated pasture on clay soil. The pastures were located in Southern Finland and were moderately contaminated with 137 Cs by Chernobyl fallout. Natural pasture refers to forest pasture and serai-natural pasture to set-aside field pasture, the latter having been under cultivation about 15 years ago. The transfer of 137Cs to sheep was clearly higher from forest pasture than from the other two pastures and it was lowest from cultivated pasture. The transfer was higher to muscle and kidney than to liver and heart. The transfer of 137Cs to plants and to meat varied with years. Seasonal variation in the plant 137 Cs was followed-up on forest and set-aside field pasture; the activity concentration of plants reached a maximum in June, a lesser increase occurred later in the autumn. In 1993, which was considered an average year with respect to 137Cs transfer to plants, the mean soil-plant transfer factors of 137Cs for forest, set-aside field and cultivated pastures were 1.78, 0.36 and 0.09, and soil-meat aggregated transfer factors 11.0, 0.28 and 0.03, respectively.

scholarly journals Adaptation to a marginal intake of energy in young children

1990 ◽  
Vol 63 (2) ◽  
pp. 145-154 ◽  
Author(s):  
N. Kennedy ◽  
A. V. Badaloo ◽  
A. A. Jackson
Keyword(s):  
Weight Loss ◽  
Regression Analysis ◽  
Marked Reduction ◽  
Linear Regression Analysis ◽  
Stool Frequency ◽  
Metabolizable Energy ◽  
The Other ◽  
N Retention ◽  
The Mean ◽  
Metabolizable Energy Intake

Six male children, aged 8–28 months, were studied for three consecutive periods of 1 week each. They were given diets that provided 1.7 g protein/kg per d and supplements of minerals and vitamins, with a metabolizable energy intake during the 1st, 2nd and 3rd week of 419, 293 and 335 kJ (100, 70 and 80 kcal)/kg per d, diets 1, 2 and 3 respectively. All the food offered was consumed. Each child was weighed at the same time each day on an electronic balance. On the 6th and 7th day of each study period urine and stool were collected for 24 h to assess nitrogen balance. Using linear regression analysis it was shown that all children gained weight on diet 1, 2.3 (sd 1.3) g/kg per d, and five of six children gained weight on diet 3, the mean for the whole group being 2.7 (sd 2.3) g/kg per d, not significantly different. On diet 2 all children lost weight, -5.4 (sd 1.3) g/kg per d, highly significantly different from each of the other dietary periods. Using asymptotic regression analysis it could be shown that the rate of weight loss during the first part of the week on diet 2, - 11 g/kg per d, was greater than at the end of the week, - 2 g/kg per d, with a tendency towards a steady weight by day 7. Apparent N retention (mg/kg per d) was positive at the end of each of the three dietary periods: diet 1, 112 (sd 25); diet 2, 54 (sd 34); diet 3, 82 (sd 20). In five of the six children there was a marked reduction in stool frequency on diet 2 compared with diet 1, that was maintained to the period on diet 3. The findings suggest that during the period on diet 2 there was a saving of energy of the order of 105 kJ (25 kcal)/kg per d, which lasted through into the period on diet 3.

Effect of Turbulence on Orifice Meter Performance

1994 ◽  
Vol 116 (2) ◽  
pp. 77-85 ◽  
Author(s):  
U. Karnik ◽  
W. M. Jungowski ◽  
K. K. Botros
Keyword(s):  
Discharge Coefficient ◽  
Tube Bundle ◽  
Orifice Plate ◽  
The Other ◽  
Turbulent Velocity ◽  
Atmospheric Conditions ◽  
Flow Conditions ◽  
The Mean ◽  
Turbulent Velocity Field ◽  
Good Flow

Mean and turbulent velocity profiles downstream of a 19-tube bundle are presented. Experiments have been carried out in 101.6-mm-dia piping configuration at prevalent atmospheric conditions with air as the fluid. The two cases considered are: one with the tube bundle placed in good flow conditions and the other with the tube bundle used as a sliding vane downstream of a single 90-deg elbow. In both cases, for various positions of the tube bundle with respect to an orifice plate, the discharge coefficient for the orifice plate has been compared to a baseline value. The results indicate that it is possible to correlate the deviations in the discharge coefficient to the mean and turbulent velocity field upstream of the orifice.

scholarly journals Evaluation of the Performance of some Evapotranspiration Models at a Tropical Location in Ile – Ife, Nigeria

2020 ◽  
Vol 8 (6) ◽  
Author(s):  
Adekunle B. Toyeje ◽  
Lukman A. Sunmonu ◽  
Ayodele P. Olufemi ◽  
Oladimeji A. Babatunde ◽  
Olawale E. Abiye ◽  
...  
Keyword(s):  
Meteorological Parameters ◽  
Soil Heat Flux ◽  
Meteorological Station ◽  
The Other ◽  
Coefficient Of Determination ◽  
Net Radiation ◽  
Climatic Region ◽  
The Mean ◽  
Reference Et ◽  
Tropical Location

This study evaluates the performance of some evapotranspiration models at Ile – Ife (7o 33’ N, 4o 33’ E) Nigeria. This was to identify suitable evapotranspiration (ET) models at the study site and to provide useful information for standardizing evapotranspiration estimations at a tropical location. Meteorological parameters (wind speed, relative humidity, temperature, solar radiation, soil heat flux, and net radiation) were routinely measured at the Obafemi Awolowo University (OAU) Meteorological Station located within the Teaching and Research Farm of the campus for a period of a month (1st – 29th July 2014). Nine standardized models for the estimation of ET; Penman-Monteith (FAO-56 PM), Priestly-Taylor (PT), Makkink (MAKK), Jensen-Haise (JH), Hargreaves-Samani (HS), Ivanov (IVA), Modified Romanenko (MROM), FAO-24 Radiation (FAO-24 RAD) and Turc (TURC) models were employed. The ET values obtained from these models were then compared to the estimated values obtained from the FAO-56 PM equation recommended as the international standard method for determining reference ET. The estimation of the ET obtained from FAO – 56 PM model ranged between 0.426 – 2.239 mm/day, MAKK, JH, and HS gave estimation closest to this, ranging from 0.544 – 2.272 mm/day. The estimation of ET from other models revealed that PT has the highest value ranging between 1.323 – 6.936 mm/day, followed closely was FAO – 24 RAD with values ranging between 1.197 – 6.500 mm/day, values of IVA model ranged from 0.620 – 1.829 mm/day, MROM value ranged from 1.240 – 3.659 mm/day, TURC has the least value ranging from 0.190 – 0.584 mm/day. Using the result of the mean biased error and regression analysis, JH model compared best with the FAO – 56 PM with coefficient of determination (R2) = 0.927; slope (b) = 0.957; mean biased error (MBE) = 0.133, this was followed closely by HS with value R2 = 0.929; b = 1.199; MBE = - 0.075 and MAKK with the value R2 = 0.931; b = 1.198; MBE = - 0.052. However, the other models showed significant over or underestimation of the ET benchmark values. The performance of the other models showed no improvement after they were recalibrated by adjusting their original coefficients. Thus, six out of the ET models employed in this study [the Priestly-Taylor (PT), Makkink (MAKK), Jensen-Haise (JH), Hargreaves-Samani (HS), FAO-24 Radiation (FAO-24 RAD) and Turc (TURC)] were found suitable for the climatic region of Ile – Ife after the adjustment of their coefficients.

scholarly journals Natural radioactivity in the soil of Thoulakhom district in Vientiane province, Laos

2019 ◽  
Vol 2 (4) ◽  
pp. 119-125
Author(s):  
Sonexay Xayheungsy ◽  
Khiem Hong Le
Keyword(s):  
Activity Concentration ◽  
Democratic Republic ◽  
Surface Soil ◽  
Natural Radionuclides ◽  
Soil Samples ◽  
Radiation Hazard ◽  
Gamma Spectrometer ◽  
Mean Values ◽  
Activity Concentrations ◽  
The Mean

Results of the first investigation of the activity concentration of the surface soil samples collected at various locations of Thoulakhom district of Vientiane province of Laos People's Democratic Republic (PDR) are presented in this work. The activity concentration of the natural radionuclides 226Ra, 232Th and 40K in the soil samples were determined by gamma spectrometer using a highenergy resolution semiconductor detector HPGe. The activity concentrations of the natural radionuclides were in the range from 11.28 to 31.46 with the mean of 21.76 Bq.kg-1 for 226Ra, from 7.13 to 44.47 with the mean of 21.85 Bq.kg-1 for 232Th and from 8.96 to 581.52 with the mean of 112.89 Bq.kg-1 for 40K. These mean values of the activity concentration were lower than the average worldwide ones, which were 33, 45 and 420 Bq.kg-1 for 226Ra, 232Th, and 40K, respectively. The results indicate dthat the radiation hazard from natural 226Ra, 232Th, and 40K radionuclides in all investigated soil samples taken from area under investigation in this work was not significant.

The influence of cation properties on the shape of silicate chains

1981 ◽  
Vol 155 (1-2) ◽  
Author(s):  
Friedrich Liebau ◽  
Ilse Pallas
Keyword(s):  
Regression Analysis ◽  
Repeat Unit ◽  
The Other ◽  
Crystal Chemical ◽  
Strongly Correlated ◽  
Single Chain ◽  
The Mean ◽  
General Relations ◽  
Periodic Chain ◽  
Silicate Chain

AbstractThe shape of silicate single chains is described by their periodicity (number of tetrahedra in the repeat unit of the chain) and the degree of shrinkage compared with a maximum stretched chain.From a regression analysis of 54 single chain silicates it is concluded that such silicates can be divided into two groups: (1) Silicates with odd-periodic chains (pyroxenoids and pyroxenes) and (2) silicates with even-periodic chains.Although the results of the analysis are not accurate enough to make reliable quantitative predictions about the shape of a silicate chain merely from the chemical composition of the silicate, some general relations could be found. So it turned out that even-periodic chains become less stretched with higher mean electronegativity and higher mean valence of their cations. In contrast, for odd-periodic chain silicates the degree of chain shrinkage is strongly correlated with the mean electronegativity and less so with the mean radius of the cations. On the other hand, the periodicity of the silicate chains is directly correlated with their degree of shrinkage. These results of the regression analysis are explained in terms of simple crystal chemical considerations.

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