Abstract
The exploring of galactic chemical composition across the the Milky Way, and specifically across the solar neighborhood, provides insights into the chemical evolution of the universe. Since ...the formation of the first stars some hundred million years after the big bang (BB), heavier elements are synthesized in different stellar production processes at the expense of lighter elements. When the relative abundances of the life-forming elements evaluated for the Last Universal Common Ancestor (LUCA) are compared with the solar neighborhood stellar abundances, a striking similarity occurs. In this study, we tested the hypothesis that in some particular regions and at some particular time, the abundance curve of the first living matter and the universe coincided. Indeed, the best agreement between the two curves was obtained for (4 ± 1)× 10
9
yr after the BB, indicating the time of the origin of life. All organisms evolved on the Earth independently of place and time are leading to the LUCA and involve chiral molecules such as L amino acids and D sugars in fundamental life processes. The growing evidence from carbonaceous meteorites analysis shows an excess of L-type amino acids and D-type sugars, suggesting that the increase in L-type or D-type molecular chirality is the process that takes place in planetary and stellar forming systems, thus the life emerging from interstellar molecular clouds (IMCs) had to be chiral. Here we propose the spin-polarized proton–proton scattering as a potential physical process that takes place in IMCs environments and could lead to enrichment of L-type amino acids and D-type sugars.
Purpose
The International Maritime Organization’s (IMO) International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) was entered into force in ...September 2017. It deals with one of the greatest threats to coastal and marine environments around the world: aquatic invasive alien species (IAS) and harmful aquatic organisms and pathogens (HAOP). Although the control of IAS and HAOP through treatment of ballast water (BW) is appropriately dealt with in the Convention and its implementation, the problems generated by sediments are not treated in such a manner.
Materials and methods
There are many published technical and scientific papers, discussions and commentaries proposing the remediation of the present situation. They are discussed, and recommendations are summarized. Besides, several systems for the treatment of BW use a combination of two or three techniques, with filtration usually being the first and/or the last step. Presence of sediments in BW results in the reduced applicability of such an approach.
Results and discussion
The requirements for sediment management procedures are discussed along with a proposal for their implementation. In the first step, the ballast tank sediments should be freed of active biological agents for the elimination of IAS and HAOP. Instead of biological agents, we advocate the use of radiation treatment by using an electron accelerator, preferably in an on-shore installation or as a mobile, additive, sea container size units with integral power, separated for water and sediment treatment. In the second step, the concentrations of heavy metals should be determined. We recommend the use of EDXRF as an analytical method. After the determination of sediment class, the recommended disposal procedures should be followed.
Conclusions
Sediment management procedures should specify the disposal requirements: (i) free of active biological agents, IAS and HAOP; (ii) chemical composition, no chemical elements in a toxic range (≤ Class 3); and (iii) displacement/storage requirements, displacing sediments characterized as harmful in appropriate sediment reception facilities/landfills.
Purpose
The objective of this study was to provide insights into the most recent responses of sediments to climate change and their capability to sequester atmospheric carbon (C).
Methods
Three ...sediment cores were collected, one from the western Black Sea, and two from the southern Adriatic Sea. Cores were extruded and sectioned into 1 cm or 0.5 cm intervals. Sections were frozen, weighed, freeze-dried, and then weighed again to obtain dry weights. Freeze-dried samples were dated by using lead 210 (
210
Pb) and cesium 137/ americium 241 (
137
Cs/
241
Am). Organic and inorganic C were determined by combustion. Particle size distribution was determined using a Beckman Coulter particle size analyzer (LS 13,320; Beckman Coulter Inc.). Mineralogical analyses were carried out by a Philips X’Pert powder diffractometer.
Results
Sedimentation and organic and inorganic C accumulation rates increased with time in both the Black Sea and the Adriatic Sea. The increase in accumulation rates continued after the global introduction in the early 1970s of controls on the release of phosphorus (P) into the environment and despite the reduced sediment yield of major rivers (Po and Danube). Therefore, the increased accumulation of organic and inorganic C in the sediments cannot be assigned only to nutrient availability. Instead, we suggest that the increase in organic C is the consequence of the increase in atmospheric C, which has made more carbon dioxide (CO
2
) available to phytoplankton, thus enabling more efficient photosynthesis. This process known as CO
2
fertilization may increase the organic C accumulation in sediments. Simultaneously, the increase of sea temperatures decreases the calcite solubility resulting in increases of the inorganic C accumulation.
Conclusion
Our results suggest that long-term, general increases in accumulation rates of organic and inorganic C in sediments are the consequence of increases in atmospheric C. This shows that coastal sediments play an important role in C uptake and thus in regulating the Earth’s climate.
The application of global open data remote sensing satellite missions in land monitoring and conservation studies is in the state of rapid growth, ensuring an observation with high spatial and ...spectral resolution over large areas. The purpose of this study was to provide a review of the most important global open data remote sensing satellite missions, current state-of-the-art processing methods and applications in land monitoring and conservation studies. Multispectral (Landsat, Sentinel-2, and MODIS), radar (Sentinel-1), and digital elevation model missions (SRTM, ASTER) were analyzed, as the most often used global open data satellite missions, according to the number of scientific research articles published in Web of Science database. Processing methods of these missions’ data consisting of image preprocessing, spectral indices, image classification methods, and modelling of terrain topographic parameters were analyzed and demonstrated. Possibilities of their application in land cover, land suitability, vegetation monitoring, and natural disaster management were evaluated, having high potential in broad use worldwide. Availability of free and complementary satellite missions, as well as the open-source software, ensures the basis of effective and sustainable land use management, with the prerequisite of the more extensive knowledge and expertise gathering at a global scale.
A multi-sensor system was evaluated for the determination of barrel content with regard to eventual pollution hazards. The proposed system is able to investigate (in situ) the interior of a barrel ...filled with various unknown substances ranging from chemical and radioactive waste, raw sewage sludge, municipal incinerator ashes to common household trash. The crucial part of the system is a neutron sensor, which enables the identification of substance content without actually opening the barrel at all. A comparative laboratory test with the 3″×3″ and 5″×5″×10″ NaI(Tl) gamma ray detectors was made after which 3″×3″ detector was selected and incorporated in the submarine called “Surveyor”. A field test was made in the Croatian Adriatic coast on the island Lošinj. Field tests show that the commercial system utilizing the described method could be constructed for barrel inspection regardless of the measurement environment (underwater, on land, dumping site, isolated location, etc.).
► A 14MeV neutron beam was used for the identification of waste in the barrel. ► The waste was composed of paint or benzene and cellulose lacquer wastes. ► Detection time depends on the carbon content. ► The carbon content of the barrel can be estimated by rotation of the neutron generator.
The prospecting activities for finding new rare earth elements (REE) sources have increased greatly in recent years. One of the main discoveries was announced in 2011 by Japanese researchers who ...found large quantities of REE on the ocean seafloor at the sea depths greater than 4,000 m. The classic approach to investigate REE in deep sea sediments is to obtain sediment samples by drilling that is followed by laborious laboratory analysis. This is very expensive, time consuming and not appropriate for exploring vast areas. In order to efficiently explore the ocean floor for REE deposits, the further development of affordable sensors is needed. Here, we propose two nuclear techniques for exploring REE in surface deep sea sediments: i) Passive measurement of lutetium-176 radioactivity, appropriate if long-term in-situ measurements are possible, and ii) The use of the neutron sensor attached to a remotely operated vehicle for rapid in-situ measurement of gadolinium by thermal neutron-capture. Since concentrations of lutetium and gadolinium show strong linear correlation to the total REE concentrations in deep sea sediments, it is possible to deduce the total REE content by measuring Lu or Gd concentrations only.
Purpose: Measurement of carbon in cores of undisturbed sediments may provide valuable information on historical trends in sea primary production and carbonate precipitation which can be related to ...climate changes. Since core sediments are usually subjected to a different analysis, it is important to preserve the sample. A non-destructive technique for carbon measurement in sediments based on fast neutron activation analysis (FNAA) has been developed, which might replace the loss-on-ignition (LOI) as a conventional method for carbon analysis.
Materials and methods: The method was tested on sediment samples collected from the Western Black Sea at depths up to 22 m. A surface sample and a core cut in centimeter intervals were freeze-dried. Samples weighing between 60 and 300 g were irradiated with the portable neutron generator. Gamma rays from
12
C(n,n'γ)
12
C nuclear reaction were counted between 2000 and 4000 s by LaBr
3
:Ce detector. Standards for direct comparison and construction of the calibration line were prepared as mixtures of different amounts of quartz sand and graphite powder. The FNAA results for total carbon (TC) were verified by LOI at 1000 °C. LOI at 450 °C and treatment with 1 M HCl were used to separate inorganic carbon (IC) and organic carbon (OC), respectively, followed by the FNAA measurements.
Results and discussion: Climate effects on physical and biological marine processes are evident as historical changes in carbon flux to sediments. Carbon in sediments is found in the form of the OC produced by photosynthetic organisms and as IC produced by calcifying organisms and precipitated as calcite. The FNAA is usually applied to samples weighing more than 1 kg. The method was optimized to reduce the minimum weight of the sample to 60 g, after subsequent adaptation of the setup geometry. Carbon content measured in cores and surface sediment was between 2.8 and 6.1 wt%. OC constituted up to 84% of TC measured in the core. The FNAA measurements were in good agreement with LOI analysis.
Conclusions: The results have shown that FNAA can be used for the non-destructive determination of carbon in sediments in samples weighing ≥ 60 g. FNAA is non-destructive, robust, and fast in comparison to conventional methods for carbon determination such as LOI. The disadvantage is a relatively high MDL of 1%.
•A proof of principle measurement system for on-line monitoring of chlorine impurity in crude oil was developed.•14MeV neutrons have been used for analyzing chlorine content in fuel oil ...samples.•Simulation models were implemented using MCNP6 and CEARCPG for design optimization of the measurement set-up.•The chlorine impurity detection limit achieved in this research was 71mg/L.
An important challenge in the petroleum industry is to reduce the salt content to acceptable levels in crude oil. Continuous monitoring of crude oil salinity is thus an important aspect. However, development of safe and reliable on-line and non-intrusive monitoring systems is still a challenging task. In this work, a method for non-intrusive, on-line monitoring of the chlorine impurity in crude oil based on prompt gamma-ray neutron activation analysis (PGNAA) in conjunction with a portable pulsed neutron generator producing 14MeV neutrons in deuterium-tritium (DT) nuclear reactions is proposed and tested. Simulations with Monte Carlo N-Particle version 6 (MCNP6) transport code combined with Center for Engineering Applications of Radioisotopes Detector Response Function (CEARDRF) and a specific purpose Monte Carlo code called Center for Engineering Applications of Radioisotopes Coincidence Prompt Gamma-Ray (CEARCPG) were used for the design optimization of the experiments. Preliminary results indicate that a minimum detection limit for chlorine impurity of about 71mg/L is achievable for an integration time of 30min.
For investigation of the basic characteristics of 14.1 MeV neutron induced nuclear reactions on a number of important isotopes for nuclear science and engineering, a new experimental setup TANGRA has ...been constructed at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research in Dubna. For testing its performance, the angular distribution of γ-rays (and neutrons) from the inelastic scattering of 14.1 MeV neutrons on high-purity carbon was measured and the angular anisotropy of γ-rays from the reaction 12C(n, n′γ)12C was determined. This reaction is important from fundamental (differential cross-sections) and practical (non-destructive elemental analysis of materials containing carbon) point of view. The preliminary results for the anisotropy of the γ-ray emission from the inelastic scattering of 14.1- MeV neutrons on carbon are compared with already published literature data. A detailed data analysis for determining the correlations between inelastic scattered neutron and γ-ray emission will be published elsewhere.
Ecological viticulture represent an upward trend in many countries. Unlike conventional viticulture, it avoids the use of chemical fertilizers and other additives, minimizing the impact of chemicals ...on the environment and human health. The aim of this study was to investigate the influence of nanofiltration (NF) process on volatiles and chemical composition of conventional and ecological Cabernet Sauvignon red wine. The NF process was conducted on laboratory Alfa Laval LabUnit M20 (De Danske Sukkerfabrikker, Nakskov, Denmark) equipped with six NF M20 membranes in a plate module, at two temperature regimes, with and without cooling and four pressures (2.5, 3.5, 4.5 and 5.5 MPa). Different processing parameters significantly influenced the permeate flux which increased when higher pressure was applied. In initial wines and obtained retentates, volatile compounds, chemical composition and elements concentration were determined. The results showed that the higher pressure and retentate cooling was more favourable for total volatiles retention than lower pressure and higher temperature. Individual compound retention depended on its chemical properties, applied processing parameters and wine composition. Nanofiltration process resulted in lower concentrations of ethanol, acetic acid (>50%), 4-ethylphenol and 4-ethylguaiacol (>90%). Different composition of initial feed (conventional and ecological wine) had an important impact on retention of elements.
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