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Search Results: 1 - 10 of 5845 matches for " gamma radiation "
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Evaluation of NORM and Dose Assessment in an Aluminium Industry in Nigeria  [PDF]
Janet Ayobami Ademola, Michael Adekunle Olatunji
World Journal of Nuclear Science and Technology (WJNST) , 2013, DOI: 10.4236/wjnst.2013.34025
Abstract:

The activity concentrations of natural radionuclides 226Ra, 232Th and 40K in bauxite ore, alumina, dross tailing, aluminium scraps and soil samples collected from an aluminium industry in Nigeria were determined by gamma ray spectroscopy method. The mean values of 226Ra, 232Th and 40K content of the samples ranged from 16 ± 6 (alumina) to 31 ± 10 (scrap), 41 ± 0.12 (scrap) to 134 ± 21(bauxite) and 47 ± 14 (bauxite) to 354 ± 8 (scrap) Bq·kg-1, respectively. The mean activity concentrations of 226Ra and 40K in all the samples are lower than the world average for soil while 232Th is higher with the exception of alumina and scrap. As a measure of radiation hazard to the occupational workers and the members of the public, the radium equivalent activities and external gamma dose rates due to the radionuclides at 1 m above ground surface were calculated. The radium equivalent activities which varied between 88 ± 10 (alumina) and 222 ± 34 (bauxite) Bq·kg-1 are within the safety recommended limit of 370 Bq·kg-1. The mean annual effective doses calculated from the absorbed dose

Effect of the radiolitic sterilization in polyethylene/starch blends
Ferreira, Flávia Gon?alves Domingues;Lima, Maria Alice Gomes de Andrade;Almeida, Yêda Medeiros Bastos de;Vinhas, Glória Maria;
Química Nova , 2008, DOI: 10.1590/S0100-40422008000500018
Abstract: samples of ldpe/modified starch blends 80/20 m/m before and after exposure to gamma rays were examined by scanning electron microscopy (sem), fourier transform infrared spectroscopy (ftir) and x-ray diffraction. the effect of gamma radiation is clearly seen in the samples irradiated at a dose of 25 kgy. the main alteration in the polymeric material after exposure at the radiation range was a decrease in the mechanical properties, alterations in the chemical structure of the blend with an increase in the carbonyl and vinyl indices and the appearance of new crystalline symmetry generating a crystalline domain not existing before in the blend.
Fermentation of irradiated sugarcane must
Alcarde, André Ricardo;Walder, Júlio Marcos Melges;Horii, Jorge;
Scientia Agricola , 2003, DOI: 10.1590/S0103-90162003000400011
Abstract: bacillus and lactobacillus are bacteria that usually contaminate the ethanolic fermentation by yeasts and may influence yeast viability. as microorganisms can be killed by ionizing radiation, the efficacy of gamma radiation in reducing the population of certain contaminating bacteria from sugarcane must was examined and, as a consequence, the beneficial effect of lethal doses of radiation on some parameters of yeast-based ethanolic fermentation was verified. must from sugarcane juice was inoculated with bacteria of the genera bacillus and lactobacillus. the contaminated must was irradiated with 2.0, 4.0, 6.0, 8.0 and 10.0 kgy of gamma radiation. after ethanolic fermentation by the yeast (saccharomyces cerevisiae) the total and volatile acidity produced during the process were evaluated; yeast viability and ethanol yield were also recorded. treatments of gamma radiation reduced the population of the contaminating bacteria in the sugarcane must. the acidity produced during the fermentation decreased as the dose rate of radiation increased. conversely, the yeast viability increased as the dose rate of radiation increased. gamma irradiation was an efficient treatment to decontaminate the must and improved its parameters related to ethanolic fermentation, including ethanol yield, which increased 1.9%.
Fermentation of irradiated sugarcane must
Alcarde André Ricardo,Walder Júlio Marcos Melges,Horii Jorge
Scientia Agricola , 2003,
Abstract: Bacillus and Lactobacillus are bacteria that usually contaminate the ethanolic fermentation by yeasts and may influence yeast viability. As microorganisms can be killed by ionizing radiation, the efficacy of gamma radiation in reducing the population of certain contaminating bacteria from sugarcane must was examined and, as a consequence, the beneficial effect of lethal doses of radiation on some parameters of yeast-based ethanolic fermentation was verified. Must from sugarcane juice was inoculated with bacteria of the genera Bacillus and Lactobacillus. The contaminated must was irradiated with 2.0, 4.0, 6.0, 8.0 and 10.0 kGy of gamma radiation. After ethanolic fermentation by the yeast (Saccharomyces cerevisiae) the total and volatile acidity produced during the process were evaluated; yeast viability and ethanol yield were also recorded. Treatments of gamma radiation reduced the population of the contaminating bacteria in the sugarcane must. The acidity produced during the fermentation decreased as the dose rate of radiation increased. Conversely, the yeast viability increased as the dose rate of radiation increased. Gamma irradiation was an efficient treatment to decontaminate the must and improved its parameters related to ethanolic fermentation, including ethanol yield, which increased 1.9%.
Assessment of environmental gamma dose in northern Rechna Doab in Pakistan
Jabbar Abdul,Bhatti Arshad S.,Ahmad Syed S.,Arshed Waheed
Nuclear Technology and Radiation Protection , 2009, DOI: 10.2298/ntrp0901056j
Abstract: Environmental gamma radiation levels in northern Rechna Doab, Pakistan, were measured as a part of systematic study aimed at the establishment of the background data base of radiation and radioactivity levels. The measurements reported in this paper were made with portable radiation monitor which employed GM tube and was calibrated against secondary standard dosimetry system. The average absorbed dose rate in air was determined to vary from 86.0 nGy/h to 139.1 nGy/h with the mean value of 109.1 nGy/h. The annual effective dose remained within the range of 105.47 mSv to 170.54 mSv with its average value of 133.73 mSv. These environmental radiation doses in the area were comparable with those reported for other countries. It was concluded that the prevalent radiation levels did not pose any significant radiological health hazard to the population.
In Vitro Evaluation of Gamma Irradiation on a Gel Formulation of Cratylia Mollis: Rheological Proporties and Microbiological Control  [PDF]
Maria Helena Madruga Lima-Ribeiro, Ralph Santos-Oliveira, Mauricélia Firmino de Santana, Terezinha de Jesus Andreoli Pinto, Irene Satiko Kikuchi, Cheila Gon?alves Mothé, Luana Cassandra Breitenbach Barroso Coelho, Maria Tereza dos Santos Correia, Ana Maria dos Anjos Carneiro-Le?o
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2012, DOI: 10.4236/jcdsa.2012.22011
Abstract: Lectin Cramoll-1,4, obtained from Cratylia mollis seeds (beans camaratu) was structurally characterized, biologically and pharmacologically, but its use as a biopharmaceutical is not well documented. The objective of this study is to propose a biopharmaceutical formulation lectin Cramoll-1,4, test their hemagglutinating properties in vitro as well as the use of gamma radiation as a continuous process of decontamination formulation. It was made of the extraction and purification Cramoll-1,4, was developed a gel formulation using Carbopol? as a vehicle, at concentrations of 50, 100, 200, 300 and 600 μg was irradiated with 60Co gamma rays in a dose of 7.549 kGy·h–1. The proposed formulation at a concentration of 300 μg produced an increase in the hemagglutinating units Cramoll-1,4 due to the synergistic effect caused by gamma radiation. Considering the diverse use of lectins, specific molecular and structural factors, as well as changes resulting from its formulation, concentration, irradiation and route of administration is of utmost importance to continue the studies in vitro, for subsequent application in vivo to characterize the physiological and molecular processes involved in the response and cellular effects.
Gamma-ray beam attenuation as an auxiliary technique for the evaluation of the soil water retention curve
BACCHI, O.O.S.;REICHARDT, K.;OLIVEIRA, J.C.M.;NIELSEN, D.R.;
Scientia Agricola , 1998, DOI: 10.1590/S0103-90161998000300019
Abstract: the soil water retention curve is fundamental for the hydraulic characterization of a soil and has many applications in agricultural research as well as in practical agriculture. a new procedure for soil moisture and soil bulk density evaluation inside closed pressure chambers through gamma-ray beam attenuation is presented. the proposed procedure presents several advantages in relation to the traditional process: avoids the need of continuous sample manipulation; minimizes the problem of hysteresis; allows a more precise evaluation of soil moisture by taking into account changes of soil bulk density due to swelling or shrinking on addition or removal of water; allows frequent evaluation of soil moisture without the need of opening the pressure chamber; allows a more precise judgement of equilibrium; reduces drastically the time of the determination of the retention curve and allows easy automation of data acquisition by a computer.
Gamma-ray beam attenuation as an auxiliary technique for the evaluation of the soil water retention curve
BACCHI O.O.S.,REICHARDT K.,OLIVEIRA J.C.M.,NIELSEN D.R.
Scientia Agricola , 1998,
Abstract: The soil water retention curve is fundamental for the hydraulic characterization of a soil and has many applications in agricultural research as well as in practical agriculture. A new procedure for soil moisture and soil bulk density evaluation inside closed pressure chambers through gamma-ray beam attenuation is presented. The proposed procedure presents several advantages in relation to the traditional process: avoids the need of continuous sample manipulation; minimizes the problem of hysteresis; allows a more precise evaluation of soil moisture by taking into account changes of soil bulk density due to swelling or shrinking on addition or removal of water; allows frequent evaluation of soil moisture without the need of opening the pressure chamber; allows a more precise judgement of equilibrium; reduces drastically the time of the determination of the retention curve and allows easy automation of data acquisition by a computer.
Radionuclide Contents and Physicochemical Water Quality Indicators in Stream, Well and Borehole Water Sources in High Radiation Area of Abeokuta, Southwestern Nigeria  [PDF]
Nnamdi Norbert Jibiri, Chijioke Micheal Amakom, George Olufemi Adewuyi
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.24033
Abstract: Water samples from streams, hand-dug wells and boreholes in high background radiation areas in Abeokuta, Nigeria have been collected in order to determine the activity concentrations of 40K, 226Ra and 232Th in the samples as well as their physicochemical characteristics. These parameters were evaluated in order to deter-mine the quality of these water sources to the local population, who use these water resources for drinking and domestic activities. Measurements of radioactivity in the water samples were carried out using γ-ray spectroscopy, while standard chemistry methods were used for the physicochemical determinations of these quality parameters. A total of fourteen representative water samples from streams (7), boreholes (4), and hand dug wells (3) were collected for study. The determined activity concentrations of the radionuclides in these samples were used to calculate the effective dose to the population from due to ingestion of and drink-ing the locally available water. The total annual ingestion effective doses were found to vary between 115.00 ± 1.15μSv and 1362.30 ± 438.02 μSv. The physicochemical parameters where found to be lower than the prescribed standard safe limits in the water sources except for the nitrate and phosphate levels which were particularly high in the water samples from boreholes and hand-dug wells. The radiation effective ingestion dose due to ingestion of water from dug wells and streams was found to be higher than the dose due to inges-tion of water from borehole sources in the studied areas. The results obtained in this study, have been taken as a baselines for physicochemical parameters and activity concentrations of natural radionuclides in water samples within Odeda and Obafemi-owode parts of Abeokuta, Nigeria.
Natural background radiation dose rate levels and incidences of reproductive abnormalities in high radiation area in Abeokuta, Southwestern Nigeria  [PDF]
Nnamdi Norbert Jibiri, John Bamidele Famodimu
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.511141
Abstract:

A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation exposure on reproductive abnormalities in the city. From the delivery record of 11,923 births in the period under study, a total number of 485 incidences of reproductive abnormalities were recoded. These incidences comprise 228 multiple births, 190 still births and, 67 premature births. Using the available terrestrial gamma radiation exposure data for the city and different reproductive abnormalities, regression assessment was carried out using the Pearson Product Moment (PPM) correlation statistics. The correlation showed that the incidences of reproductive abnormalities and the radiation dose levels were negatively correlated and correlation coefficient values were very low for each of the reproductive abnormalities considered. Factors such as socio-economic potentials of patients, dietary and other environmental factors may have substantial influence on the reproductive defects in the area other than radiation. However, the present study has added to the radiometric information needed in understanding the relationship between natural outdoor radiation exposure and occurrences of reproductive abnormalities in areas of high radiation in the country.

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