Using radial basis artificial neural networks to predict radiation hazard indices in geological materials.

The estimation of exposures to humans from the various sources of radiation is important. Radiation hazard indices are computed using procedures described in the literature for evaluating the combined effects of the activity concentrations of primordial radionuclides, namely, 238U, 232Th, and 40 K. The computed indices are then compared to the allowed limits defined by International Radiation Protection Organizations to determine any radiation hazard associated with the geological materials. In this paper, four distinct radial basis function artificial neural network (RBF-ANN) models were developed to predict radiation hazard indices, namely, external gamma dose rates, annual effective dose, radium equivalent activity, and external hazard index. To make RBF-ANN models, 348 different geological materials' gamma spectrometry data were acquired from the literature. Radiation hazards indices predicted from each RBF-ANN model were compared to the radiation hazards calculated using gamma spectrum analysis. The predicted hazard indices values of each RBF-ANN model were found to precisely align with the calculated values. To validate the accuracy and the adaptability of each RBF-ANN model, statistical tests (determination coefficient (R2), relative absolute error (RAE), root mean square error (RMSE), Nash-Sutcliffe Efficiency (NSE)), and significance tests (F-test and Student's t-test) were performed to analyze the relationship between calculated and predicted hazard indices. Low RAE and RMSE values as well as high R2, NSE, and p-values greater than 0.95, 0.71, and 0.05, respectively, were found for RBF-ANN models. The statistical tests' results show that all RBF-ANN models created exhibit precise performance, indicating their applicability and efficiency in forecasting the radiation hazard indices of geological materials. All the RBF-ANN models can be used to predict radiation hazard indices of geological materials quite efficiently, according to the performance level attained.

Metal toxin threat in wildland fires determined by geology and fire severity.

Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust. Underrecognized, however, are the health threats arising from fire-altered toxic metals natural to soils and plants. Here, we demonstrate that high temperatures during California wildfires catalyzed widespread transformation of chromium to its carcinogenic form in soil and ash, as hexavalent chromium, particularly in areas with metal-rich geologies (e.g., serpentinite). In wildfire ash, we observed dangerous levels (327-13,100 µg kg-1) of reactive hexavalent chromium in wind-dispersible particulates. Relatively dry post-fire weather contributed to the persistence of elevated hexavalent chromium in surficial soil layers for up to ten months post-fire. The geographic distribution of metal-rich soils and fire incidents illustrate the broad global threat of wildfire smoke- and dust-born metals to populations. Our findings provide new insights into why wildfire smoke exposure appears to be more hazardous to humans than pollution from other sources.

Geological control of terrestrial background radiation in Garhwal Himalaya, India.

Activity concentrations of 226Ra, 232Th, and 40K were measured in soil samples from several areas of Garhwal Himalaya, Northern India, by gamma-ray spectrometry. In this region, which extends around the Himalayan Main Central Thrust, a tectonic line that separates several geological provinces, background levels of natural terrestrial radiation were assessed. The maximum levels of radium, 285 Bq/kg and 136 Bq/kg, respectively, were found in the Budhakedar and Uttarkashi regions, exceeding the world average value of 35 Bq/kg. The mean radiation levels were found to be different between the areas, which reflects the geological diversity in the region. The overall absorbed dose rate owing to radionuclide presence in the Uttarkashi area ranged from 79 to 188 nGyh-1, with an average of 118 nGyh-1. That is more than UNSCEAR's world-populated weighted average value of 59 nGyh-1. The present investigation indicated that the absorbed dose rates are greater in Uttarkashi and Budhakedar than in other places. The multiple comparison analysis between geology and absorbed dose rate shows that the geology of Uttarkashi and Budhakedar are statistically similar. According to several hazard indices, terrestrial background radiation is not of radiological concern in the investigated region.

Radiation protection for well logging operations in Saudi Arabia.

In well logging, sophisticated tools are inserted into a borehole to measure physical and geological properties of rocks surrounding the well. Some of these, known as nuclear logging tools, contain radioactive sources and are used to obtain useful information. When logging tools containing radioactive sources are inserted into the well, there is a risk that they may get stuck. If this occurs, a recovery operation, known as fishing, is used to attempt retrieval. If fishing fails to recover the radioactive sources, they are abandoned following an established protocol, which is in accordance with international, national and corporate standards, in addition to industry best practices. This paper provides an overview of radiation protection requirements for well logging operations in Saudi Arabia, to ensure the safety and security of radioactive sources, and the protection of workers and the public without impacting operational productivity.

Estimating geothermal and background radiation hotspots from primordial radionuclide concentrations in geology of South Africa.

Naturally occurring radionuclides are the main generator of geothermal energy in the Earth's crust and mantle. The generated energy is consequently directly proportional to the concentrations of the three main naturally occurring radionuclides (uranium, thorium and potassium), which are primordial in origin. Concentrations of these naturally occurring radionuclides were extracted for all the different geological rock units in South Africa. The radionuclide concentrations were then mapped and integrated by using QGIS. The results were used to estimate and map the geothermal energy production rates for the rock units. The radionuclide concentrations in the rock units were also used to identify regions with high radiation background. These radiation hotspots were plotted and investigated. The estimated geothermal energy and background radiation hotspots were compared to measurements and projections of other studies and good corelations were found.

Antropoceno, ciências humanas e historiografia / Anthropocene, human sciences and historiography

Resumo O artigo mostra, inicialmente, como as discussões sobre o Antropoceno têm se deslocado de maneira cada vez mais significativa para o campo das ciências humanas. Em seguida, tomando como ponto de partida a proposta de que as ciências humanas deveriam contribuir para a compreensão do "metanível consequencial" dos estudos sobre o Antropoceno, discute como alguns trabalhos produzidos nesse campo têm lidado com as relações entre causas, efeitos e consequências diante das condições do novo regime planetário, considerando de maneira especial as discussões sobre a "tecnosfera". Conclui indicando o potencial das novas perspectivas ontológicas das ciências humanas para a ampliação dos horizontes explicativos e comunicativos da historiografia.

Abstract The article initially presents an increasingly significant move of discussions about the Anthropocene towards humanities and social sciences. Then, taking as a starting point the proposal that these fields could contribute to the understanding of the "consequential meta-level" of studies on the Anthropocene, it discusses how some works produced in humanities and social sciences have dealt with the relationship between causes, effects and consequences regarding the new planetary regime, with a special focus on the debate about the "technosphere." It concludes by indicating the potential of the "ontological turn" to expand the explanatory and communicative horizons of historiography.

Shale gas geological "sweet spot" parameter prediction method and its application based on convolutional neural network.

Parameters such as gas content (GAS), porosity (PHI) and total organic carbon (TOC) are key parameters that reveal the shale gas geological "sweet spot" of reservoirs. However, the lack of a three-dimensional high-precision prediction method is not conducive to large-scale exploration of shale gas. Although the parameter prediction accuracy based on well logging data is relatively high, it is only a single point longitudinal feature. On the basis of prestack inversion of reservoir information such as P-wave velocity and density, high-precision and large-scale "sweet spot" spatial distribution predictions can be realized. Based on the fast growing and widely used deep learning methods, a one-dimensional convolutional neural network (1D-CNN) "sweet spot" parameter prediction method is proposed in this paper. First, intersection analysis is carried out for various well logging information to determine the sensitive parameters of geological "sweet spot". We propose a new standardized preprocessing method based on the characteristics of the well logging data. Then, a 1D-CNN framework is designed, which can meet the parameter prediction of both depth-domain well logging data and time-domain seismic data. Third, well logging data is used to train a high-precision and robust geological "sweet spot" prediction model. Finally, this method was applied to the WeiRong shale gas field in Sichuan Basin to achieve a high-precision prediction of geological "sweet spots" in the Wufeng-Longmaxi shale reservoir.

Evaluation of soil-gas radon concentrations from different geological units with varying strata in a crystalline basement complex of southwestern Nigeria.

The aim of this study is to determine the variation of soil-gas radon concentrations from different rock formations in Ogbomoso, southwestern Nigeria. The radon concentrations at different five geological domains in Ogbomoso are determined with respect to depth. The measurements varied from the surface (0 cm) to 100 cm depth, with an interval of 20 cm. At all the geological domains (Porphyroclastic, Granite, Quartzite, Migmatite and Banded gneiss), radon has its minimum emission over migmatite at 0 cm, while its maximum emissions occured over granite and banded gneiss at 80 cm. The overall soil-gas radon concentrations in Ogbomoso varied from 0.06 to 26.5 kBq/m3, which is within the natural limit of 0.4 to 40 kBq/m3 based on the International Commission on Radiological Protection's recommendation. An F-ratio of 6.989 and a p-value of 0.001 were obtained for the first inferential hypothesis, while an F-ratio of 2.489 and a p-value of 0.076 were obtained for the second inferential hypothesis using ANOVA test. The post hoc (using Tukey HSD and Duncan) tests revealed that at 60 + cm, depth controls the level of radon concentrations being emanated from the subsurface. The pollution index in Ogbomoso is of level 1 at 80 cm and level 0 (safe limit) at other depths. In conclusion, the soil-gas radon emission depends on the local geology and lithological sequences (depths). Cracks that could act as passage for indoor radon at the floors of the buildings around the polluted zones should be avoided in order to have a sustainable city.

The Radiation Environment of Ceres and Implications for Surface Sampling.

Ceres is a large water-rich dwarf planet located within the asteroid belt. Its surface displays evidence of material sourced from a deep subsurface liquid brine layer within recent geologic time, making it a candidate ocean world with possible present-day activity. However, Ceres lacks a substantial atmosphere and likely does not possess a global magnetic field. Therefore, any material emplaced or exposed on the surface will be subject to weathering by charged particles of solar and galactic origin. We have evaluated the effect of charged particle radiation on material within the near-surface of Ceres and find that the timescale for radiation-induced modification and destruction of organics and endogenic material is ∼100 Myr to 1 Gyr within the top 10-20 cm of the surface. Furthermore, we find that the timescale for sterilization of any putative living organisms contained within material at these depths is <500 kyr. Future missions to the surface may therefore consider targeting regions with geologic ages that fall between these two timescales to avoid the risk of backward contamination while ensuring that sampled material is not heavily radiation processed.

Long-Term In-Situ Monitoring and Analysis of Terrain in Gas Hydrate Trial Harvesting Area.

With the increase in global energy demand, the exploration and development of natural gas hydrate in sea has become a research hotspot in recent years. However, the environmental problems that may be brought about by large-scale harvesting are still concerns. The terrain monitoring of the trial harvesting area can effectively prevent the geological disasters that may be caused by the development of hydrates. Therefore, we have developed a new terrain monitoring device, which can work in the deep sea for a long time. Firstly, the structure of the sensor arrays and bus-type control system of the device are introduced. Secondly, an arc model with an interpolation method is used for reconstruction of the monitored terrain. Thirdly, after the accuracy of the sensing arrays are verified in laboratory, the device was placed in the Shenhu area of the South China Sea for more than 6 months of in-situ monitoring. Finally, we analyzed the data and concluded that the terrain of the monitored area was relatively flat, where the maximum subsidence was 12.3 cm and the maximum uplift was 2.75 cm.

Noble gas adsorption to tuff.

A method was developed to measure trace noble gas element adsorption to the surfaces of geologic materials in the presence of a background gas that could potentially compete for surface adsorption sites. Adsorption of four noble gas elements (Ne, Ar, Kr, and Xe) at a concentration of 100 ppm in helium and nitrogen were measured on a sample of crushed tuff at 0, 15, 30, and 45 °C. In addition, Ne, Ar, Kr, and Xe at 250 ppm and 500 ppm in nitrogen at 15 °C were measured. Noble gas adsorption was found to increase with increasing atomic mass and decreasing temperature. It was also observed that the relative increase in noble gas element adsorption with decreasing temperature tends to increase with increasing atomic mass. As the noble gas concentrations in nitrogen increased, adsorption increased in a slightly non-linear fashion which could be modeled using a Freundlich isotherm. For noble gas concentrations that were ≤100 ppm Henry's Law constant were calculated.

Biological, geological and chemical effects of oxygen injection in underground gas storage aquifers in the setting of biomethane deployment.

The last few years have seen the proliferation of anaerobic digestion plants to produce biomethane. Oxygen (O2) traces added to biogas during the desulfurization process are co-injected in the gas network and can be stored in Underground Gas Storage (UGS). However, there are no data available for the undesirable effects of O2 on these anoxic environments, especially on deep aquifers. In addition to mineral alteration, O2 can have an impact on the anaerobic autochthonous microbial life. In our study, the storage conditions of an UGS aquifer were reproduced in a high-pressure reactor and bio-geo-chemical interactions between the aqueous, gas and solid phases were studied. Sulfate was depleted from the liquid phase for three consecutive times during the first 130 days of incubation reproducing the storage conditions (36 °C, 60 bar, methane with 1% CO2). Sulfate-reducers, such as Desulfovibrionaceae, were identified from the high-pressure system. Simulations with PHREEQC were used to determine the thermodynamic equilibrium to confirm any gas consumption. CO2 quantities decreased in the gas phase, suggesting its use as carbon source by microbial life. Benzene and toluene, hydrocarbons found in traces and known to be biodegradable in storages, were monitored and a decrease of toluene was revealed and associated to the Peptococcaceae family. Afterwards, O2 was added as 1% of the gas phase, corresponding to the maximum quantity found in biomethane after desulfurization process. Re-oxidation of sulfide to sulfate was observed along with the end of sulfate reducing activity and toluene biodegradation and the disappearance of most of the community. H2 surprisingly appeared and accumulated as soon as hydrogenotrophic sulfate-reducers decreased. H2 would be produced via the necromass fermentation accomplished by microorganisms able to resist the oxic conditions of 4.42·10-4 mol.Kgw-1 of O2. The solid phase composed essentially of quartz, presented no remarkable changes.

Temporal variation of planetary iron as a driver of evolution.

Iron is an irreplaceable component of proteins and enzyme systems required for life. This need for iron is a well-characterized evolutionary mechanism for genetic selection. However, there is limited consideration of how iron bioavailability, initially determined by planetary accretion but fluctuating considerably at global scale over geological time frames, has shaped the biosphere. We describe influences of iron on planetary habitability from formation events >4 Gya and initiation of biochemistry from geochemistry through oxygenation of the atmosphere to current host-pathogen dynamics. By determining the iron and transition element distribution within the terrestrial planets, planetary core formation is a constraint on both the crustal composition and the longevity of surface water, hence a planet's habitability. As such, stellar compositions, combined with metallic core-mass fraction, may be an observable characteristic of exoplanets that relates to their ability to support life. On Earth, the stepwise rise of atmospheric oxygen effectively removed gigatons of soluble ferrous iron from habitats, generating evolutionary pressures. Phagocytic, infectious, and symbiotic behaviors, dating from around the Great Oxygenation Event, refocused iron acquisition onto biotic sources, while eukaryotic multicellularity allows iron recycling within an organism. These developments allow life to more efficiently utilize a scarce but vital nutrient. Initiation of terrestrial life benefitted from the biochemical properties of abundant mantle/crustal iron, but the subsequent loss of iron bioavailability may have been an equally important driver of compensatory diversity. This latter concept may have relevance for the predicted future increase in iron deficiency across the food chain caused by elevated atmospheric CO2.

O novo regime climático do Antropoceno e de Gaia / The new climatic regime of Anthropocene and Gaia / El nuevo régimen climático del Antropoceno y de Gaia

Resumo O artigo discute os conceitos de Antropoceno e de Gaia, apontados por Bruno Latour como categorias para entender o regime climático que estamos vivendo e servir de base teórica para buscar respostas apropriadas para a crise do clima. Os conceitos buscam superar dois pressupostos da racionalidade moderna: a oposição entre natureza e cultura - questionando o princípio de que os humanos são os únicos atores da realidade e introduzindo todos os seres vivos como agentes conformadores do ambiente - e a visão globalizante do planeta Terra, que impede de ver a terra como solo localizado onde acontecem os ciclos biogeoquímicos de transformação da energia que possibilitam a vida. Conclui-se que a reflexão de Latour fornece bases ontológicas para a discussão sobre a mudança climática e pressupostos para a bioética ambiental.

Abstract This article discusses the concepts of Anthropocene and Gaia, raised by Bruno Latour, as categories to understand the climate regime we are experiencing and serve as a theoretical basis to seek appropriate responses to the climate crisis. These concepts seek to overcome two assumptions of modern rationality: the opposition between nature and culture - questioning the principle that humans are the only actors in reality and introducing all living beings as agents shaping the environment - and the globalizing vision of planet Earth that prevents us from seeing it as localized soil where biogeochemical cycles of energy transformation that make life possible take place. It is concluded that Latour's reflection provides ontological bases for the discussion on climate change and assumptions for environmental bioethics.

Resumen Este artículo discute los conceptos de Antropoceno y Gaia, señalados por Bruno Latour como categorías para entender el régimen climático que estamos viviendo y para servir de base teórica para buscar respuestas adecuadas a la crisis climática. Los conceptos buscan superar dos supuestos de la racionalidad moderna: la oposición entre naturaleza y cultura -cuestionando el principio de que los humanos son los únicos actores de la realidad e introduciendo a todos los seres vivos como agentes conformadores del medio ambiente- y la visión globalizante del planeta Tierra, que impide ver la tierra como un suelo localizado en el que tienen lugar los ciclos biogeoquímicos de transformación de la energía que hacen posible la vida. Se concluye que la reflexión de Latour proporciona bases ontológicas para la discusión sobre el cambio climático y supuestos para la bioética ambiental.

The "Table of mineral classification" by Oscar Nerval de Gouvêa: mineralogy and medicine in Brazil / A "Tabela de classificação mineral", de Oscar Nerval de Gouvêa: mineralogia e medicina no Brasil

Abstract Oscar Nerval de Gouvêa was a scientist and teacher in Rio de Janeiro, Brazil, whose work spanned engineering, medicine, the social sciences, and law. This paper presents and discusses a manuscript entitled "Table of mineral classification," which he appended to his dissertation Da receptividade mórbida , presented to the Faculty of Medicine in 1889. The foundations and features of the table provide a focus for understanding nineteenth-century mineralogy and its connections in Brazil at that time through this scientist. This text was Gouvêa's contribution to the various mineral classification systems which have emerged from different parts of the world.

Resumo Oscar Nerval de Gouvêa foi um cientista e professor no Rio de Janeiro, Brasil, cuja obra abrange engenharia, medicina, ciências sociais e direito. Este artigo apresenta e discute o texto intitulado "Tabela de classificação mineral", que ele anexou a sua tese Da receptividade mórbida, apresentada na Escola Superior de Medicina, em 1889. Os fundamentos e características da tabela propiciam a compreensão da mineralogia do século XIX e suas conexões no Brasil à época por intermédio desse cientista. O texto foi a contribuição de Gouvêa aos diversos sistemas de classificação de minerais originados de diferentes partes do mundo.

Producción científica de la Facultad de Geología y Minas del Instituto Superior Minero Metalúrgico, Cuba, en el período 2003-2015 / Scientific production of the Geology and Mining Faculty of Higher Institute of Mining and Metallurgy, Cuba, in period 2003-2015

RESUMEN El objetivo de la investigación fue describir la producción científica de la Facultad de Geología y Minas del Instituto Superior Minero Metalúrgico de Moa (Cuba), en revistas científicas durante el período 2003-2015. El estudio se desarrolló a través de una estrategia de investigación que combina técnicas exploratorias de búsqueda de información y análisis cuantitativos, mediante el análisis documental y la estadística descriptiva. En este sentido, se analizó la producción científica por años, departamentos docentes, autores y en revistas. Se consultó un total de 224 publicaciones, de ellas 80 en revistas científicas, a partir de la identificación de los focos temáticos de investigación, la información contenida en los curriculum vitae y la consulta a las bases de datos. Los resultados muestran la evolución e impacto de la producción científica en los doce años del período en estudio. Se concluye que, a pesar de que el número de publicaciones registradas en revistas científicas es pequeño, existe una correspondencia entre la producción científica y las líneas de investigación establecidas por la institución. Estos resultados son un reflejo de los intereses y áreas activas de esta Facultad, por lo que los resultados pueden constituir un indicador de su evolución en la institución.

Abstract The purpose of the research was to describe the scientific production of the Geology and Mining School of the Higher Institute of Mining and Metallurgy of Moa (Cuba), in scientific journals during 2003-2015 period. The study is developed by means of a research strategy that combines exploratory techniques of information search and quantitative analyses, through the documentary analysis and descriptive statistics. In this sense analyzed the scientific production for years, teaching departments, authors, and journals. A total of 224 publications were surveyed, of those 80 in scientific journals, through of the identification of the thematic focuses of research, the information given in the curriculum vitae and the databases queries. The results show the evolution and impact of the scientific production in the twelve years of the period under study. It concluded that, despite the number of registered publications in scientific journals is small, there is a matching between the scientific production and the established lines of investigation by the institution. These results reflect the interests and active areas of this Faculty, so the results can be an indicator of his evolution in the institution.

Assessment of radiation hazards from phosphate rocks, Sibaiya area, central eastern desert, Egypt.

The present work used the integrated Carbone γ-ray spectrometric data and HPGe γ-ray spectrometer data to the prospect of radioactive zones at the Sibaiya area, Central Eastern Desert, Egypt. Carbone γ-ray spectrometric survey revealed ten uranium anomalies distributed along the car traverse from west to east direction have values of 240, 104, 44, 34, 150, 124, 232, 132, 60, and 90 ppm, respectively. These significant anomalies are associated mainly with phosphates mines characterized by a substantial increase of eU/eTh and eU/K ratios. Ten phosphate samples were collected from the determining anomalies. They were analyzed using the HPGe detector gamma-ray spectrometer. It was found that the results of radioelement concentrations by carborne survey agree well with that obtained by HPGe. The average activity concentration for the Sibaiya phosphate samples under study is 152.5, 947, and 33.2 Bq/kg against the worldwide accepted limit of 412, 33, and 45 Bq/kg for 40K, 238U, and 232Th, respectively. The radium equivalent ranges from 499 to 3484.9 Bq/kg, which is higher than the recommended value 370 Bq/kg. The external hazard's (Hex) calculated values range from 1.35 to 9.42 mGy/yr, and the internal hazard (Hin) ranges from 2.58 to 18.69. These indexes must be lower than unity to keep the radiation hazard insignificant. The value of the radioactivity level index (Iγ) is found to be more than unity, which varies between 1.68 and 11.63. The dose rate (DR) ranges from 149.5 to 970 nGy/h, higher than the international mean value of 55 nGy/h. The annual effective dose ranges from 0.18 to 1.19 mSv, which less than unity in almost all values. Meanwhile, the values of activity of 226Ra ranged from 454 to 3429 Bq/kg and the mean of mass radon exhalation rate (Jm) is 6615 mBq kg-1 h-1 which is lower than the worldwide average.

Plutonium in coral archives: A good primary marker for an Anthropocene type section.

While we officially live in the Holocene epoch, global warming and many other impacts of global change have led to the proposal and wide adoption of the Anthropocene to define the present geological epoch. The Anthropocene Working Group (AWG) established that it should be treated as a formal stratigraphic unit, demonstrated by a reference level commonly known as "golden spike", still under discussion. Here we show that the onset of bomb-derived plutonium recorded in two banded massive corals from the Caribbean Sea is consistent (1955-1956 CE), so sites far from nuclear testing grounds are potentially suitable to host a type section of the Anthropocene. Coastal coral demonstration sites are feasible, could foster economic development, and may serve as focal points for scientific dissemination and environmental education.

Interpretation of geophysical data for iron ore detailed survey in Laje, Bahia, Brazil.

The transition zone between the Archean blocks, Jequié and Itabuna-Salvador-Curaçá, in the county of Laje, Bahia, Brazil, is potentially important for iron ore deposits of economic interest. This research investigates one of the eighteen anomalies defined by a previous integrated interpretation of geological and airborne gamma ray spectrometry and magnetic data in this transition zone. Its choice resulted from being located in an area with intense transcurrent shear and from the occurrence of pebbles rich in magnetite. Because of paucity of surface geological information, a ground-based geophysical survey added valuable information for the definition of a drilling program in the area. The survey consisted of two parts and followed up the aforementioned previous integrated interpretation of the Valença sheet. The first part consisted of one gravity and magnetic profile, which indicated a favorable site for additional investigation. The second part consisted of a detailed survey in the selected area with gravity, magnetic, and VLF-EM. The interpretation of the data of the geophysical methods allowed to delineate two zones in the area, both located at magnetic anomalies, gravity highs and relatively conductive parts. The two zones have a high potential for iron ore, because they present significant and correlated anomalies.