On the theory of bubble coarsening in metals Ovcharenko, Alexey M.; Chernov, Ivan I.
Journal of nuclear materials,
January 2020, 2020-01-00, 20200101, Volume:
528
Journal Article
Peer reviewed
A comprehensive analysis of simulation results obtained recently by the authors in modeling of gas bubble evolution driven by the Ostwald ripening process in irradiated metals has been carried out. ...Relevant experimental data characterized by a relatively small mean bubble radius measured in a range of about 1–5 nm in stainless steel specimens containing 100 appm He and annealed at 1023 K have also been used in this study. A comparison of both the experimental and simulation data with analytical estimations predicted by the original theory at the late stage of bubble coarsening was considered unsatisfactory. To overcome this inconsistency, a new approach has been applied assuming that bubbles evolve at significantly different rates at either earlier or later stages of the process. Despite the difference of the rates in these cases, a complete similarity of corresponding asymptotic bubble size distributions has been detected. Experimentally observable time dependences of bubble density and mean bubble radius agree well with the recent modeling and our present analysis results. This indicates that Ostwald ripening provides a reasonable explanation for bubble evolution during annealing. Unlike the conventional interpretation of bubble coarsening, growing bubbles attain chemical equilibrium with interstitial gas emitted by shrinking bubbles. It is this assumption which allows for getting the asymptotic bubble size distribution function similar to that given by the classical theory of Ostwald ripening.
Existing data on Myxozoa parasites infecting mullets were reviewed. The validity of nine species names was updated. Sixteen species were registered during analysis of original material collected in ...the Mediterranean, Black, Azov, and Japan Seas in 2004–2005. A new bivalvulid myxozoan parasite, Myxobolus adeli n. sp., was described from the inner organs of the golden grey mullet Liza aurata (Risso, 1810) collected in the Mediterranean (Ebro Delta, Spain), Black Sea (Kerch Strait, Ukraine), and Azov Sea (Genichesk, Ukraine) coastal waters. It is characterized by the presence of elongated, spindle-like cysts 0.5–1.3 mm in size, filled with wide transverse-oval spores about 6.2 × 7.2 × 4.6 μm in size, with two equal polar capsules measuring about 3.0 × 1.8 μm and short polar filament, turned into four coils. The obtained data show that this species differs from all previously described Myxobolus spp. with equal polar capsules. Comparative study of Myxobolus spp. recorded in worldwide mullets indicates a close relationship with M. adeli n. sp. and Myxobolus improvisus Isjumova, 1964 registered in mullets. Probably, the last species includes representatives of some different species, infecting freshwater and marine hosts.
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•Dispersal of alien species is a global problem threatening native biodiversity.•The microsymbiotic community was rich in native amphipods and poor in invasive hosts.•Host species and ...locality are key drivers shaping the structure of microsymbionts.•Habitat condition was a stronger determinant of richness than geographic distance.•Random distribution of microsymbiotic species richness was common in gammarids.
Dispersal of alien species is a global problem threatening native biodiversity. Co-introduction of non-native parasites and pathogens adds to the severity of this threat, but this indirect impact has received less attention. To shed light on the key factors determining the richness of microorganisms in native and invasive host species, we compared symbiotic (parasitic and epibiotic) communities of gammarids across different habitats and localities along the Baltic coast of Poland. Seven gammarid species, two native and five invasive, were sampled from 16 freshwater and brackish localities. Sixty symbiotic species of microorganisms of nine phyla were identified. This taxonomically diverse species assemblage of symbionts allowed us to assess the effect of host translocation and regional ecological determinants driving assembly richness in the gammarid hosts. Our results revealed that (i) the current assemblages of symbionts of gammarid hosts in the Baltic region are formed by native and co-introduced species; (ii) species richness of the symbiotic community was higher in the native Gammarus pulex than in the invasive hosts, probably reflecting a process of species loss by invasive gammarids in the new area and the distinct habitat conditions occupied by G. pulex and invasive hosts; (iii) both host species and locality were key drivers shaping assembly composition of symbionts, whereas habitat condition (freshwater versus brackish) was a stronger determinant of communities than geographic distance; (iv) the dispersion patterns of the individual species richness of symbiotic communities were best described by Poisson distributions; in the case of an invasive host, the dispersion of the rich species diversity may switch to a right-skewed negative binomial distribution, suggesting a host-mediated regulation process. We believe this is the first analysis of the symbiotic species richness in native and invasive gammarid hosts in European waters based on original field data and a broad range of taxonomic groups including Microsporidia, Choanozoa, Ciliophora, Apicomplexa, Platyhelminthes, Nematoda, Nematomorha, Acanthocephala and Rotifera, to document the patterns of species composition and distribution.
Relevance. The ability to provide more accurate and efficient assessment and management of hydrocarbon production using software products for integrated field modeling. However, this approach ...requires an analysis of the source data quality, as well as the selection of the correct approach to creating models. Consistent and systematic work makes it possible to reproduce the actual situation with high accuracy in order to use the results obtained in further work. The integrated field model is a completely new approach to field development, when current work is based not on existing solutions, but on potential. Forecasting the behavior of the reservoir, wells and infrastructure, the collection system and the system for maintaining reservoir pressure allows for a comprehensive assessment of the possibilities of obtaining maximum oil and gas production while minimizing possible losses. Aim. Formation and analysis of an approach to setting up PVT-models of fluids, models of injection well stock, collection and transport systems and reservoir pressure maintenance systems by adapting parameters to actual data. Methods. Setting up and adapting injection well models; setting up and adapting collection system and pipeline models; approach to work with the reservoir pressure maintenance system. Results. The results obtained make it possible to adapt the components of the integrated model with an accuracy of over 95 %, which makes it possible to simulate the operating conditions of the field. Because of the analysis, tuning criteria were identified, and the minimum required set of parameters for high-quality adaptation of models was presented. Efficiency and accuracy of predictive calculations on adapted models has also been proven by comparing actual performance data with synthetic data. Based on the work done, we can conclude that the use of an integrated model shows us a high convergence with real data, which allows us to optimally approach the field development regime.
Relevance. Current situation, when an increasing number of subsoil users are moving towards the correct choice of a development system. Therefore, the applicability of integrated asset models is ...growing exponentially every year. One of the integrated approaches in the field of reservoir–well–ground infrastructure modeling is the use of Petroleum Experts software. This solution has successfully established itself in the international market due to the presence of a large number of various correlations suitable for certain geological conditions, as well as a complex methodology for calculating the tasks. Thanks to the above product, the tasks of calculating the inflow from a reservoir, well flow rate and infrastructure throughput analysis formed a single integrated solution for high-quality modeling of fields/groups of fields. In its turn, the Petroleum Experts Prosper software allows you to evaluate the efficiency of a well, as well as to obtain additional production through optimization calculations on a well model tuned to actual parameters. Aim. To form and analyze the approach to setting up component models (wells) by adapting parameters to actual data in order to obtain additional oil production. Methods. Setting up and adaptation of well models equipped with installations of electrical center pumps, setting up and adaptation of fountain wells, approach to working with a periodical fund, assessment of the effectiveness of the use of Prosper in terms of additional oil production. Results. The results obtained allow us to adapt well models with an accuracy of more than 95%, which simulates the operating mode of the mechanized and fountain mining fund in order to optimize and increase oil production. As a result of the analysis, the criteria for tuning wells were identified, and the minimum necessary set of parameters for high-quality adaptation of models was presented. The effectiveness and accuracy of the method by comparing the actual data on the regimes of the wells with synthetic are also proved. Based on the work done, we can conclude that the use of an integrated model shows us a high convergence with real data, which allows you to conduct optimization calculations with high accuracy with obtaining a result that provides the greatest effect.
Extensive connective tissue lysis is a common outcome of haplosporidian infection. Although such infections in marine invertebrates are well documented, they are relatively rarely observed in ...freshwater invertebrates. Herein, we report a field study using a comprehensive series of methodologies (histology, dissection, electron microscopy, gene sequence analysis, and molecular phylogenetics) to investigate the morphology, taxonomy, systematics, geographical distribution, pathogenicity, and seasonal and annual prevalence of a haplosporidian observed in zebra mussels, Dreissena polymorpha. Based on its genetic sequence, morphology, and host, we describe Haplosporidium raabei n. sp. from D. polymorpha – the first haplosporidian species from a freshwater bivalve. Haplosporidium raabei is rare as we observed it in histological sections in only 0·7% of the zebra mussels collected from 43 water bodies across 11 European countries and in none that were collected from 10 water bodies in the United States. In contrast to its low prevalences, disease intensities were quite high with 79·5% of infections advanced to sporogenesis.
Dikerogammarus villosus is an invasive amphipod that recently colonized the main rivers of Central and Western Europe. Two frequent microsporidian parasites were previously detected in this species, ...but their taxonomic status was unclear. Here we present ultrastructural and molecular data indicating that these two parasites are in fact a single microsporidian species. This parasite shares numerous characteristics of Nosema spp. It forms elongate spores (cucumiform), developing in direct contact with host cell cytoplasm; all developmental stages are diplokaryotic and the life cycle is monomorphic with disporoblastic sporogony. Initially this parasite was described as Nosema dikerogammari Ovcharenko and Kurandina 1987. However, phylogenetic analysis based on the complete sequence of SSU rDNA places the parasite outside the genus Nosema and it is therefore ascribed to a new genus Cucumispora. The key features characteristic to this genus are: presence of a very well-developed, umbrella-shape anchoring disk covering the anterior part of polaroplast; arrangement of isofilar polar filament into 6-8 coils convoluted with different angles, voluminous diplokaryon, thin spore wall and relatively small posterior vacuole containing posterosome. The parasite infects most host tissues but mainly muscles. It showed high rates of horizontal trophic transmission and lower rates of vertical transmission.
The diversity and taxonomy of metacercariae infecting freshwater amphipods of Poland are predominantly poorly known. During parasitological surveys of Gammarus pulex (Crustacea: Amphipoda) in the ...Pomeranian region of Poland in 2020 and 2021, some specimens of crustaceans were found to harbour metacercariae. Out of seven observed localities, metacercariae were found in the stream close to Krępa Słupska and the Lupawa River close to Smoldzino. They were morphologically studied and sequenced using universal eukaryotic primers that amplify V4–V5 regions of 18S rRNA. The BLAST analysis and phylogenetic reconstructions aid to define the affiliation of the revealed metacercariae within the Omphalometridae Looss, 1899. The further differential analysis based on morphologic information led to the conclusion that the metacercarial form studied herein represents Neoplagioglyphe megastomus (Baer, 1943). The degree of morphometric variations of taxonomic important features in populations from different geographic regions was followed up. The reported here form was characterized by a larger body size that was affected by the processing methods used in the present and previous studies. To our knowledge, this is the first report of Neoplagioglyphe megastomus in Poland and is the first molecular characterization of the worm
The article summarizes and analyzes the main impacts of various xenobiotics or their groups on the human body and the consequences of such exposure. The study suggests the refinements to the ...generally accepted classification of xenobiotics’ origins. The paper also describes the molecular mechanism of foreign substances biotransformation in a human body. The metabolism of xenobiotics differs due to their forms and types’ varieties. The factors of influence on chemicals’ metabolism are also of great importance. Individual features of the metabolism may be associated with genetic differences in the activity of metabolic enzymes. The research results further the comprehension of the exposure pathways and health impacts of the xenobiotics and their metabolites.
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