Hydrogeological, hydrochemical, and natural isotopes evaluation of groundwater and surface water interactions in the alluvial plain, tropical region of southeastern Brazil

Groundwater-Surface water interactions in alluvial plains facing morphological features are the subject of the study. Considered transitions zones, alluvial plains have different morphological features interfering with groundwater flow and hydrochemistry. The alluvial plain of Mogi Guaçu river (southeastern Brazil) presented topography-controlled groundwater flow, nevertheless, natural levees, wet fields, oxbow lakes, and abandoned meanders can control local flow and interfere in discharges points of the main river. Two sampling water campaigns were done in the dry and wet season for physicochemical and natural isotopes analysis, collecting in total 44 groundwaters samples from monitoring wells and eight water samples from the river, creek, and lake. The groundwaters in wet fields and terraces, and surface waters from creek and lake presented low mineralization (EC from 8 to 37 μS.cm), pH acidic (4.98 to 5.8), and essentially Ca and Na-HCO composition. River waters samples presented pH between 5.92 e 7.69 (acidic in the rainy season and basic in the dry season), and EC from 24.2 and 181.1 μS/cm (lower values in the wet season), Na-HCO and Na-HCO-SO (dry season) and Ca-HCO and Na-HCO (rainy season) compositions. In dry season groundwaters composition showed evolution from sodium mixed (SO – HCO) to bicarbonate waters and higher mineralization; in wet season waters varied from Ca to Na-HCO composition and low mineralization, denoting dilution due to rainwater infiltration. Closer to the river margins, in abandoned meanders and oxbows, the groundwaters have increased values of EC and major ions indicating GW-SW mixtures, and effluent-influent changes (descendent and ascendent flux) in wet and dry seasons, respectively. Natural isotopes in groundwaters imply meteoric origin, without evaporation during recharge and high d-excess can be influenced by continental air masses and Amazonia Basin low-level jet. Shallow water table, permeable silty-sand material of vadose zone, flat terrain, and pristine conditions can contribute to direct infiltration of rainwaters, recharging the shallow aquifer.

CALCULATION OF STAGES OF THE TECHNOLOGICAL PROCESS OF MANUFACTURE OF PPD DETECTORS USING COMPUTER MATHEMATICAL MODELING AND PRODUCTION OF ALPHA RADIOMETER ON THEIR BASIS

The article describes the developed radiometer for Express measurement of alpha radiation of radioactive elements based on a large-diameter silicon detector. The main element of the PPD detector is made using computer mathematical modeling of all stages of the technological process of manufacturing detectors, taking into account at each stage the degree of influence of the properties of the initial silicon on the electrophysical and radiometric characteristics of the detector. Detectors are manufactured for certain types of devices. The developed radiometer is designed to measure alpha radiation of natural isotopes (238U, 234U, 232Th, 226Ra, 222Rn, 218Po, 214Bi, etc.) in various environments. It also shows the principle of operation of the device, provides a block diagram of the measuring complex, describes the electronic components of the radiometer, as well as the block diagram. Signal transformations (spectrum transfer, filtering, accumulation) are implemented programmatically on the basis of a digital processing module. The device can detect the presence of specific elements in various environments, as well as protect people from the harmful effects of adverse radiation and can be used both in the field and stationary.

NEW OPPORTUNITIES OF NUCLEAR PHYSICS RESEARCH OF THE OBJECTS OF ENVIRONMENT IN THE COURT EXPERTISE ACTIVITY

In this paper are studied the possibility of using nuclear techniques, in particular, low-background measurements of the radionuclide content of natural (isotopes of natural series U / Th, 40K) and man-made origin for the identification of natural objects as non-nuclear materials. In particular, this can be the samples of soil, river sludge or rock, presented as evidential objects for court expertise. Тhe proposed technique explores new data on the nature of the nucleosynthesis of the Earth’s crust, the distribution and conditions of radioactive equilibrium of the daughter’s isotopes of the U / Th series. Recent studies show the ability to use lowbackground research data to establish standards for the content / ratio of the clarks of chemical elements U / Th / K, which may be sufficient identification signs of a given territory like fingerprints for a person. This is especially relating to such objects of the environment as samples of soils, rocks, etc. that are genetically related to a given territory. Considering these environmental objects as a subject of court examination, we can talk about their important role as an evidence-based argument, which in many cases allows us to identify the origin of the “criminal element”. Therefore, the methods of identification of environmental objects and their binding to a certain territory are very important. The paper presents the first examples of such studies on samples of soil, river sludge and rock, taken from protected areas of Transcarpathia, the influence of manmade factors on which is minimal. It justifies the choice of the minimum number of radionuclide tags of a given territory, the method of sampling to obtain the radiation characteristics of a given area, and the statistical stability of the obtained data on the content of the studied radionuclides for different series of obtained samples is investigated. Systematic studies of this kind make it possible to carry out radiation mapping of territories as the development of the ideas of Vernadsky about the importance of taking into account ground-based radiation and to get a more accurate binding of the objects under study to a specific region. The possibility of using the nuclear dating technique in forensic analysis according to low-background measurements about the content of natural U / Th series in environmental objects is shown. The results of nuclear dating of samples of the Carpathian rocks using the uranium method are presented. Summing up, it can be said that nuclear techniques can be used not only to analyze radioactive materials, but also to complement effectively traditional physicochemical studies of the non-nuclear materials as forensic objects.

Synthesis and Characterization of New Lithium and Boron Based Metal Organic Frameworks with NLO Properties for Application in Neutron Capture Therapy

In this work, we synthetized and characterized new crystalline materials with theranostic properties, i.e., they can be used both as bio-sensors and for “drug delivery”. The two solid crystalline compounds studied are Metal Organic Frameworks and have formulas Li[(C6H12O6)2B]·2H2O and Li[(C4H2O6)2B]·5.5H2O. They can be synthetized both with natural isotopes of Li and B or with 6Li and 10B isotopes, that can be explored for Neutron Capture Therapy (NCT) for anti-cancer treatment. The presence of chiral organic molecules, such as mannitol and tartaric acid, provides the NLO property to the crystals and thus their capability to generate the Second Harmonic, which is useful for applications as bio-sensors. The two compounds were characterized with X-ray Diffraction and the Second Harmonic Generation (SHG) responses were estimated by theoretical calculations, and the results were compared with experimental measurements of powdered samples. In order to test the behavior of such compounds under thermal neutron irradiation, we preliminary exposed one of the two compounds in the e_LiBANS facility at the Torino Physics Department. Preliminary results are reported.

Validity of natural isotope abundance correction for metabolic flux analysis

A pervasive issue in stable isotope tracing and metabolic flux analysis is the presence of naturally occurring isotopes such as 13C. For mass isotopomer distributions (MIDs) measured by mass spectrometry, it is common practice to correct for natural isotopes within metabolites of interest using a particular linear transform based on binomial distributions. However, the origin and mathematical derivation of this transform is rather obscure, and it may be difficult for nonexperts to understand precisely how to interpret the resulting corrected MIDs. Moreover, corrected MIDs are often used to fit metabolic network models and infer metabolic fluxes, which implicitly assumes that corrected MIDs will yield the same flux solution as the actual observed MIDs. Yet, there seems to be no published proof of this important property. Here, we provide a detailed derivation of the MID-correcting linear transform, reflecting its historical development, and describe some interesting properties. We also provide a proof that for metabolic flux analysis on noise-free MID data at steady state, observed and corrected MIDs indeed yield the same flux solution. On the other hand, for noisy MID data, the flux solution will generally differ between the two representations.

Application of complex statistical distributions and natural isotopes of hydrogen and oxygen for assessment of water origin in Sar Mountains aquatorium

This study considers the possibility of applying natural isotopes of water, tritium, and oxygen 18O, to analyze the connection between groundwater, surface, and precipitation waters. This analysis also enables the determination of the age of groundwater, separated from the cycle of water circulation in nature. Based on these methods, it is possible to reliably determine, by chronologically accurate method, the possibility of industrial application and application for human needs of the waters of this aquatorium.