Management and environmental risk study of the physicochemical parameters of ballast water

Shipping is a vital industry for the global economy. Stability of ships, provided by ballast water, is a crucial factor for cargo loading and unloading processes. Ballast water treatment has practical significance in terms of environmental issues, ecosystem, and human health, because ships discharge this water into the environment before loading their cargos. This study reviews the common methods for ballast water management – exchange, heating, filtration, ultrasonic treatment, ultraviolet irradiation, chemicals, and gas supersaturation – to select the best one. This study compares water temperature, salinity, dissolved oxygen, polycyclic aromatic hydrocarbons (PAHs), and heavy metals (Co, Cr, Ni, Pb) for ballast tanks of selected ships with the recipient port environment in the Persian Gulf as a case study. The exchange of ballast water in the ocean and/or its treatment on board to prevent inadvertent effects on the environment's physicochemical conditions is related to vessel characteristics, legislation, and the environmental condition. Ecological risk study showed that the salt content in ballast water is close to that of seawater, but the values of Cr (2.1 mg/l) and Ni (0.029 mg/l) in ballast water are higher than those in seawater (1 and 0.004 mg/l, respectively).     

Do mowing regimes affect plant and soil biological activity in the mountain meadows of Southern Poland?

The soil biological activity of mountain meadows is a significant factor that determines the health and utility of these regions. The climax stage of this area is forest, but to maintain semi-natural grassland, which is characterised by high biodiversity,low-intensity land use(mowing or grazing) is necessarily required. To understand the effect of various mowing regimes on the soil biological activity and plants, the soil microbial activity(microbial biomass carbon, dehydrogenase activity and number of the cultivable fraction of soil microbial community),annelids community(density and species composition earthworms and enchytraeids) and plant species composition were investigated. The study area was located in the Pieniny National Park in the Carpathian Mountains, in a meadow belonging to the association Dactylis glomerata-Poa trivialis. The investigated variants were divided according to mowing regime:traditional scything – hand mowing(HM), mechanical mowing(MM), or the abandonment of mowing – nonmowing(NM). The microbial activities(expressed by,e.g. microbial biomass carbon and the number of phosphorus bacteria) were affected by the mowing regime. The density of earthworms was higher in the HM and MM than in the NM variants. The largest changes in plant species composition were caused by the abandonment of mowing(NM). The mean number of plant species was positively correlated with soil moisture, earthworm density, and microbial activity(expressed indirectly by dehydrogenases activity). The soil microbial community, such as vegetative bacteria forms and ammonifying bacteria,were positively associated with pH value, and the microbial and total organic carbon content. The results presented here indicate that there is no single form of optimal management for all living organisms.Decisions about mowing regimes, or abandonment of use, should be preceded by multi-aspect studies,including plants and soil biota.     

High-Reflectivity Coatings for a Vacuum Ultraviolet Spectropolarimeter

Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-\(\upalpha \) (Ly\(\upalpha \); 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Ly\(\upalpha \) optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Ly\(\upalpha \), whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (\(\sim 5~\%\) on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Ly\(\upalpha \) line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.     

Estimation of crack opening from a two‐dimensional continuum‐based finite element computation

Damage models are capable of representing crack initiation and mimicking crack propagation within a continuum framework. Thus, in principle, they do not describe crack openings. In durability analyses of concrete structures however, transfer properties are a key issue controlled by crack propagation and crack opening. We extend here a one‐dimensional approach for estimating a crack opening from a continuum‐based finite element calculation to two‐dimensional cases. The technique operates in the case of mode I cracking described in a continuum setting by a nonlocal isotropic damage model. We used the global tracking method to compute the idealized crack location as a post‐treatment procedure. The original one‐dimensional problem devised in Dufour et al. [4] is recovered as profiles of deformation orthogonal to the idealized crack direction are computed. An estimate of the crack opening and an error indicator are computed by comparing finite element deformation profiles and theoretical profiles corresponding to a displacement discontinuity. Two estimates have been considered: In the strong approach, the maxima of the profiles are assumed to be equal; in the weak approach, the integrals of each profile are set equal. Two‐dimensional numerical calculations show that the weak estimates perform better than do the strong ones. Error indicators, defined as the distance between the numerical and theoretical profiles, are less than a few percentages. In the case of a three‐point bending, test results are in good agreement with experimental data, with an error lower than 10% for widely opened crack (> 40µm). Copyright © 2011 John Wiley & Sons, Ltd.     

叶缘—年均温中国模型在定量重建中国新生代植物群古年均温中的应用

叶缘分析法是一种利用现代植被木本双子叶植物全缘叶物种百分比与年均温的函数关系,定量重建化石植物群古年均温的方法。该方法在新生代植物群的古年均温定量重建研究中得到了广泛的应用。目前基于世界不同地区现代植被的研究表明,尽管全缘叶物种百分比与年均温存在很好的相关性,但其相关性具有地区差异性。本文旨在总结叶缘分析法的研究进展,并介绍基于中国植被建立的叶缘—年均温中国模型;同时,采用该模型重建了中国新生代不同时期植物群的古年均温,且与前人采用其它模型得到的年均温重建值相比较。结果表明,叶缘—年均温中国模型能够有效地重建中国新生代植物群的古年均温值。     

A Time-Evolving 3D Method Dedicated to the Reconstruction of Solar Plumes and Results Using Extreme Ultraviolet Data

An important issue in the tomographic reconstruction of the solar poles is the relatively rapid evolution of the polar plumes. We demonstrate that it is possible to take into account this temporal evolution in the reconstruction. The difficulty of this problem comes from the fact that we want a four-dimensional reconstruction (three spatial dimensions plus time) whereas we only have three-dimensional data (two-dimensional images plus time). To overcome this difficulty, we introduce a model that describes polar plumes as stationary objects whose intensity varies homogeneously with time. This assumption can be physically justified if one accepts the stability of the magnetic structure. This model leads to a bilinear inverse problem. We describe how to extend linear inversion methods to these kinds of problems. Studies of simulations show the reliability of our method. Results for SOHO/EIT data show that we can estimate the temporal evolution of polar plumes to improve the reconstruction of the solar poles from only one point of view. We expect further improvements from STEREO/EUVI data when the two probes will be separated by about 60°.     

Geochemical characterization of moldavites from a new locality,the Cheb Basin,Czech Republic

Abstract— Twenty‐three moldavites from a new locality, the Cheb Basin in Western Bohemia, were analyzed by instrumental neutron activation analysis for 45 major and trace elements. Detailed comparison of the Cheb Basin moldavites with moldavites from other substrewn fields in both major and trace element composition shows that the Cheb Basin is a separate substrewn field. The geochemical data obtained are discussed with respect to the source materials and processes leading to formation of moldavites. The data show that three groups of Cheb Basin moldavites exist. Ten samples of group 1 are characterized by the lowest content of Al, Fe, Na, and other elements representing phyllosilicate minerals, and by high Ca + Mg contents related probably to carbonates. They resemble the “poisonous green” moldavites, a subgroup of the Southern Bohemian moldavites. Seven samples of group 2 and 6 samples of group 3 are similar to typical moldavites of the Southern Bohemian substrewn field. These two groups differ from each other mainly in Al contents; with higher contents of Al and the elements associated with phyllosilicate minerals (namely Ba and Sr), group 3 also resembles the Moravian moldavites. Significant positive correlations between K, Ca, Mg, and Mn found in group 2 of the Cheb Basin moldavites and the enrichment in these elements observed generally in all moldavites, as well as other facts, e.g., high K/Na and K/Rb ratios and the reduced conditions during formation of moldavites, have been attributed to possible contribution to the moldavite source materials of the ash produced by burning of vegetation and soil organic matter present at the pre‐impact area.     

Evaporation in Mediterranean conditions: Estimations based on isotopic approaches at the watershed scale

In Mediterranean regions, the marked climatic seasonality and uneven precipitation distribution complicate the application of isotope mass balances to obtain meaningful basin-wide annual average evaporation rates. In the present study, a mass balance approach carried out on the Tavignanu River watershed in Corsica (France), showed unrealistic evaporation rate estimates: 10% for 2017–2018 and 1% for 2018–2019. This suggests that not only does evaporation alter the seasonal isotopic composition in the river, but that there is complex variability of the dominant water reservoirs contributing to the streamflow. Therefore, we propose a modified mass balance approach, including monthly quantifications of different water sources contributing to the river discharge. This allows the discrimination of isotopic variation occurring by evaporation from that originating by mixing processes. By applying this modified approach, we estimated evaporation rates on the Tavignanu River watershed that were in good agreement with results obtained by hydrological modelling: 40% for 2017–2018 and 46% for 2018–2019, respectively. An uncertainty analysis showed that evaporation rates obtained with the modified isotopic approach are close to those obtained with the non-modified approach. Therefore, we recommend using this modified isotope mass balance approach to estimate evaporation rates in such regions as the Mediterranean with high seasonality in hydrological processes.