Measurements of X- and Gamma Radiation at Ground Level and their Correlation with Atmospheric Electric Discharges and Rainfall in São José dos Campos, SP, Brazil

Mineral mining and milling can be a source of national economic and technological development. However, mining of minerals has been confirmed to disturb the natural distribution of radioisotopes in the soil, air and water bodies in the biota. In an attempt to evaluate the radiological burden resulting from tin mining activities at Rayfield-Du area of Jos, the background gamma-radiation level in the mine was measured via a well calibratedhand-held dosimeter placed at 1 m above ground level. The mean absorbed dose rate, annual effective dose rate and excess lifetime cancer risk for the mine was 0.83 μSvh-1; 1.44 mSv-1 and 0.005 respectively. Generally, dose rates were higher in the mine pits and processing areas as compared to administrative areas of the mine. The mean measured dose rate and calculated dose parameters for the mine were all high when compared to the regulatory limit for public exposure. The potential of developing radiation-induced health defects as a result of high radiation absorbed dose rate by the miners and dwellers around the mine is highly probable. Keywords: Gamma-radiation; mine; absorbed dose rate; radiation exposure.

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Intensity variation of gamma radiation on ground level interface in São Jose Dos Campos, SP, Brazil

Latin American Journal of Development ◽

10.46814/lajdv3n2-029 ◽

2021 ◽

Vol 3 (2) ◽

pp. 853-858

Author(s):

Inacio M. Martin ◽

Marcelo P. Gomes

Keyword(s):

Relative Humidity ◽

Gamma Radiation ◽

Gas Dynamics ◽

Intensity Variation ◽

Ground Level ◽

Rain Intensity ◽

Daily Fluctuation ◽

Relative Humidity Range ◽

Humidity Range ◽

Measurement Period

In the period June 22 to September 24, 2012 São José dos Campos region experienced dry climate with low relative humidity. The net rain intensity measured in this period was 60 mm/h and the relative humidity range between 30% to 40% on most days. The intensity of gamma radiation from 0.03 to 10.0 MeV, in the measurement period presents a daily fluctuation well clearly, and some small increases when there is rainfall. These measures were realized at ITA's campus with a scintillator of NaI(Tl), photomultiplier and associated electronics laptop to a Dell 630 PC. A data acquisition interface purchased from (Aware Eletronics, USA) provides a file with measurements versus time, in the range from minute to minute recorded in txt. It was observed that the variation of gamma radiation in the interface soil/air at the region is originating from the local radon gas dynamics and of the presence of wind shear near the ground level.

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III. Investigations on lighting discharges and on the electric field of thunderstorms

Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character ◽

10.1098/rsta.1921.0003 ◽

1921 ◽

Vol 221 (582-593) ◽

pp. 73-115 ◽

Cited By ~ 275

Keyword(s):

Electric Field ◽

Potential Gradient ◽

Ground Level ◽

Electric Discharges ◽

Test Plate ◽

Before And After ◽

Flat Portion ◽

The Difference ◽

Zero Potential ◽

Absolute Measurements

The method and apparatus used in the measurements are substantially those described in a paper "On Some Determinations of the Sign and Magnitude of Electric Discharges in Lightning Flashes." The induced charge on an exposed earthed conductor (test-plate or sphere) is used as a measure of the electric field. The testplate virtually forms part of a flat portion of the earth’s surface, and the vertical electric force or potential gradient at ground level is equal (in electrostatic measure) to 4 π Q/A, where Q is the charge on its exposed surface and A is its area. The charge Q on the earth-connected sphere of radius R, when exposed at a height h , great compared with R, is a measure of the potential at that height; the zero potential of the sphere being the resultant of the undisturbed atmospheric potential V at the height h and of the potential Q/R due to the charge on the sphere, so that Q/R = - V. The earthed conductors can be shielded from the earth’s field: the test-plate by means of an earth-connected cover, the sphere by lowering it into a conducting case resting on the ground. The quantity of electricity which flows to earth through the connecting wire on exposing or shielding the test-plate or sphere, is measured by a special type of capillary electrometer in which the readings indicate the total quantity of electricity which has traversed the instrument ; the sign and magnitude of the charge on the exposed conductor, and thus of the potential gradient, at the beginning and end of an exposure are thus determined. The sign and magnitude of sudden changes of potential gradient which occur while the conductor is exposed are indicated by the direction and magnitude of the resulting displacements of the electrometer meniscus. The total flow of electricity between the atmosphere and the test-plate or sphere during an exposure is also measured —being given by the difference between the electrometer readings before and after the exposure. The principal improvement introduced has been the provision of apparatus for giving a photographic trace of the electrometer readings; rapid changes in the field occupying less than one-tenth of a second are in this way recorded. In the observations described in the previous paper the sphere was supported in a manner which did not admit of absolute measurements being made, as the charge measured included that on the upper part of the support as well as that on the sphere itself; in these earlier measurements therefore the sphere was standardised by comparison with the test-plate. The method of supporting the sphere is now such that the charge on the sphere alone is measured, while the disturbing effect of the earthed supporting rod is small, and thus the potential at the level of the earthconnected sphere can be calculated from the charge upon it. The new method of mounting the sphere is shown in fig. 1.

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Intensity variation of gamma radiation on ground level interface in São Jose dos Campos, SP, Brazil

Latin American Journal of Development ◽

10.46814/lajdv3n4-065 ◽

2021 ◽

Vol 3 (4) ◽

pp. 2615-2621

Author(s):

Alexandre Santos De Souza ◽

Cleber Souza Correa ◽

Inacio Malmonge Martin

Keyword(s):

Relative Humidity ◽

Gamma Radiation ◽

Gas Dynamics ◽

Intensity Variation ◽

Ground Level ◽

Rain Intensity ◽

Daily Fluctuation ◽

Relative Humidity Range ◽

Humidity Range ◽

Measurement Period

In the period June 22 to September 24, 2012 São José dos Campos region experienced dry climate with low relative humidity. The net rain intensity measured in this period was 60 mm/h and the relative humidity range between 30% to 40% on most days. The intensity of gamma radiation from 0.03 to 10.0 MeV, in the measurement period presents a daily fluctuation well clearly, and some small increases when there is rainfall. These measures were realized at ITA's campus with a scintillator of NaI(Tl), photomultiplier and associated electronics laptop to a Dell 630 PC. A data acquisition interface purchased from (Aware Eletronics, USA) provides a file with measurements versus time, in the range from minute to minute recorded in txt. It was observed that the variation of gamma radiation in the interface soil/air at the region is originating from the local radon gas dynamics and of the presence of wind shear near the ground level. No período de 22 de junho a 24 de setembro de 2012, a região de São José dos Campos experimentou um clima seco com baixa umidade relativa. A intensidade líquida de chuva medida neste período foi de 60 mm/h e a umidade relativa varia entre 30% a 40% na maioria dos dias. A intensidade de radiação gama de 0,03 a 10,0 MeV, no período de medição apresenta uma flutuação diária bem clara, e alguns pequenos aumentos quando há chuva. Estas medidas foram realizadas no campus da ITA com um cintilador de NaI(Tl), fotomultiplicador e laptop eletrônico associado a um PC Dell 630. Uma interface de aquisição de dados adquirida da (Aware Eletronics, EUA) fornece um arquivo com medidas versus tempo, na faixa de minutos a minutos gravados em txt. Foi observado que a variação da radiação gama na interface solo/ar na região é originada pela dinâmica local do gás radônio e da presença de cisalhamento do vento próximo ao nível do solo.

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Ground to Cloud Lightning Flash Currents and Electric Fields: Interaction with Aircraft and Production of Ionosphere Sprites

Journal of Computational Engineering ◽

10.1155/2014/869452 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

P. R. P. Hoole ◽

S. Thirukumaran ◽

Harikrishnan Ramiah ◽

Jeevan Kanesan ◽

S. R. H. Hoole

Keyword(s):

Frequency Spectrum ◽

Electric Fields ◽

Electric Circuit ◽

Ground Level ◽

Transverse Magnetic ◽

Lightning Flash ◽

Electric Discharges ◽

Electric Currents ◽

Safety Testing ◽

Cloud To Ground Lightning

This paper presents for the first time a case for the importance of ground to cloud (upward leader) lightning flash parameters for safety testing of direct aircraft-lightning interaction and protection of wind turbines, as well as the importance of radiated electric fields for indirect lightning-aircraft interaction and generation of electric discharges called sprites and halos in the ionosphere. By using an electric circuit model of the transverse magnetic waves along the return stroke channel, electric currents at ground level as well as cloud level are determined for both the cloud to ground lightning flash and the ground to cloud lightning flash. We show that when an aircraft triggers lightning, the electric currents will be much more severe in current magnitude, rate of rise of currents, and frequency spectrum than otherwise and are more severe than the parameters observed for the usual and well monitored (and measured) cloud to ground (downward leader) flashes. The rate of rise of currents and the frequency spectrum of the ground to cloud lightning flash are also given here. The electric fields radiated by the lightning flashes that would appear in the ionosphere are presented for both the earth flash and the ground to cloud flash.

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INVESTIGATION OF EQUIVALENT DOSE RATE VARIATION IN THE GROUND‐LEVEL AIR BY LITHUANIAN HIGHWAYS

Journal of Environmental Engineering and Landscape Management ◽

10.3846/16486897.2006.9636872 ◽

2006 ◽

Vol 14 (1) ◽

pp. 3-9

Author(s):

Donatas Butkus ◽

Kristina Živilė Gaponovienė

Keyword(s):

Gamma Radiation ◽

Dose Rate ◽

Absorbed Dose ◽

Ground Level ◽

Weighting Factor ◽

Equivalent Dose ◽

Rate Variation ◽

Soil Composition ◽

Equivalent Dose Rate ◽

Ground Level Air

This investigation deals with equivalent dose rate (EDR) of the ground‐level air caused by gamma radiation. Weighting factor for gamma radiation is equal to one, therefore, EDR of the ground‐level air should be similar to the absorbed dose from the ionic radiation dose. In this paper the main parameters which determine the level of equivalent dose rate in the ground‐level air by the Lithuanian highways are defined and analysed. EDR in the ground‐level air by Lithuanian highways was measured and compared to similar average regional values with reference to modeling results evaluating value variation reasons. In the investigation of EDR the ground‐level air was measured in winter and summer. Samples of soil and asphalt were examined with a gamma spectrometer. It was determined that dependence of EDR values in the ground‐level air correlated and depended upon the soil composition, floral or snow cover and distance from an asphalt cover. Cosmic radiation impact on EDR formation is equal at all the locations. Gamma radiation of natural‐origin radionuclides in the soil have the greatest influence on EDR formation in the ground‐level air. The modeling program VISIPLAN was used to define impact of radionuclide radiation from an asphalt cover on EDR formation in a roadside zone. The modeling program InterRAS was used to define EDR formation in the ground‐level air due to gamma radiation of the soil radionuclides.

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Effects of Vibration on the Preparation of Ultrathin Sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007223x ◽

1973 ◽

Vol 31 ◽

pp. 358-359

Author(s):

Joseph M. Blum ◽

Edward P. Gargiulo ◽

J. R. Sawers

Keyword(s):

Cutting Speed ◽

Ground Level ◽

Environmental Vibration ◽

Block Face ◽

Ultrathin Sections ◽

Embedding Medium ◽

Thickness Variations ◽

Building Walls ◽

Cutting Direction ◽

Diamond Knife

It is now well-known that chatter (Figure 1) is caused by vibration between the microtome arm and the diamond knife. It is usually observed as a cyclical variation in “optical” density of an electron micrograph due to sample thickness variations perpendicular to the cutting direction. This vibration might be induced by using too large a block face, too large a clearance angle, excessive cutting speed, non-uniform embedding medium or microtome vibration. Another prominent cause is environmental vibration caused by inadequate building construction. Microtomes should be installed on firm, solid floors. The best floors are thick, ground-level concrete pads poured over a sand bed and isolated from the building walls. Even when these precautions are followed, we recommend an additional isolation pad placed on the top of a sturdy table.

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Effects of sterilization modes on the mechanical strengths of plaster of paris implants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156432 ◽

1989 ◽

Vol 47 ◽

pp. 890-891

Author(s):

K. Cowden ◽

B. Giammara ◽

T. Devine ◽

J. Hanker

Keyword(s):

Gamma Radiation ◽

Calcium Sulfate ◽

Significant Loss ◽

Potassium Sulfate ◽

Limiting Factors ◽

Radiation Sterilization ◽

Plaster Of Paris ◽

Hardness Tester ◽

Dry Heat ◽

Calcium Sulfate Hemihydrate

Plaster of Paris (calcium sulfate hemihydrate, CaSO4. ½ H2O) has been used as a biomedical implant material since 1892. One of the primary limiting factors of these implants is their mechanical properties. These materials have low compressive and tensile strengths when compared to normal bone. These are important limiting factors where large biomechanical forces exist. Previous work has suggested that sterilization techniques could affect the implant’s strength. A study of plaster of Paris implant mechanical and physical properties to find optimum sterilization techniques therefore, could lead to a significant increase in their application and promise for future use as hard tissue prosthetic materials.USG Medical Grade Calcium Sulfate Hemihydrate Types A, A-1 and B, were sterilized by dry heat and by gamma radiation. Types A and B were additionally sterilized with and without the setting agent potassium sulfate (K2SO4). The plaster mixtures were then moistened with a minimum amount of water and formed into disks (.339 in. diameter x .053 in. deep) in polyethylene molds with a microspatula. After drying, the disks were fractured with a Stokes Hardness Tester. The compressive strengths of the disks were obtained directly from the hardness tester. Values for the maximum tensile strengths σo were then calculated: where (P = applied compression, D = disk diameter, and t = disk thickness). Plaster disks (types A and B) that contained no setting agent showed a significant loss in strength with either dry heat or gamma radiation sterilization. Those that contained potassium sulfate (K2SO4) did not show a significant loss in strength with either sterilization technique. In all comparisons (with and without K2SO4 and with either dry heat or gamma radiation sterilization) the type B plaster had higher compressive and tensile strengths than that of the type A plaster. The type A-1 plaster however, which is specially modified for accelerated setting, was comparable to that of type B with K2SO4 in both compressive and tensile strength (Table 1).

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