Reconstruction of fission events in heavy ion reactions with the compact spectrometer for heavy ion experiment

We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-area parallel-plate avalanche counters, which can deliver the position and arrival timing information of the fragments. The start timing information is provided by the radio frequency of the cyclotron. Fission events were reconstructed using the velocities of the two FFs. The broadening of both the velocity distribution and azimuthal difference of the FFs decreases with the folding angle, in accordance with the picture that fast fission occurs. The anisotropic angular distribution of the fission axis also consistently reveals the dynamic features of fission events.

Assessing discharge periodicity in mountain catchments using classified environmental conditions(Tatra Mountains, Poland)

The periodicity of a river expressed in cycles of various lengths(monthly, seasonal,multiannual) is a result of climatic factors and overlapping environmental conditions within its catchment. In uncontrolled or poorly surveyed catchments, it is very difficult to determine the duration of a stream’s hydrological activity. This is especially relevant for catchments with complicated water circulation in karstic rocks. The present study concerns the small catchment of the Str??yski Potok river located in the area of the Tatra National Park, in the Western Tatras. The observation period covered the 2015 hydrological year, which differed hydrologically from average conditions. This study aims to develop a simple method to explain the processes shaping the mountain stream discharge periodicity. The research employed periodic field observations linked with climatic and non-climatic factors. Environmental conditions were assessed as four classes reflecting their influence on appearance or disappearance of mountain stream water. Class boundaries were the values of quartiles. The degree of correspondence between environmental factors and stream field observations was described via the Index DC(Degree Correspondence Index) approach.Complete correspondence(Index DC =0) was found in 23% catchments, a weak relationship between conditions favouring discharge and actual condition(Index DC=-1, +1) was noted within 11 catchments,while in 9 catchments, no such relationship was found(Index DC =-2, +2). The obtained results indicate a correspondence or lack thereof between the environmental potential of the catchment and its discharge periodicity. The discrepancies between the assessment of the influence of climatic and nonclimatic factors and the data collected during field observations provide a basis for more detailed studies.Continuation of these studies based on the proposed classifications will allow for a more complete explanation of water disappearance in river channels and the determination of their short-and long-term discharge periodicity.

Analysis of Internal Factors of the Swing States in the International Climate Change Negotiations: A Case Study of Poland in COP24

The objective of this paper is to generate insights into the role of states in the international climate change negotiations and implementation of climatic agreements by considering their internal factors based on recent climate change conferences. In this paper, the notion of swing states and recognition are used to determine influential drivers in Poland as it played out a different role over climate change agreements recently. The case study of Poland demonstrates how international obligations, domestic factors, and formation of policy can change the function of a state at international negotiations such as Katowice Conference of Parties—COP24—in December 2018. This research through reference to qualitative indices elaborates how the position of Poland in the recent international climate change negotiations—Cop24—has been shaped? In the conference of parties 24, Poland approached other developed countries that shared its tendency for cutting emission, delivered signals of political attention and solidarity in finding a common landing ground. In sum, the framework of analysis and our results revealed the importance of economic interest, domestic political interests, and passive public awareness to set up to the task in the international agreements such as Katowice negotiation by Poland. To be clearer, the most influential factor of Poland in affecting its role in international climatic negotiations is internal political and economic interests.

Preparation,Characterization and Catalytic Activity of Palladium Nanoparticles Embedded in the Mesoporous Silica Matrices

Novel in-situ reduction approach was applied for the synthesis of palladium nanoparticles in the pores of mesoporous silica materials with grafted siliconhydride groups. Matrices possessing different structural properties (MCM-41, SBA-15 and Silochrom) were used. Samples were studied by nitrogen adsorption-desorption method, low-angle X-ray diffraction, transmission electron microscopy (TEM) and FT-IR/PAS spectroscopy. The temperature-programmed oxidation (TPO) and reduction (TPR) methods were applied to examine reducibility of palladium species. Palladium containing catalysts were tested in methane oxidation reaction. It was demonstrated that relatively large pores in SBA-15 type silica facilitated formation of well-dispersed palladium nanoparticles confined in the pores channels. In the case of MCM-41 support, metallic palladium nanoparticles were formed on the external surface. The obtained materials showed high catalytic activity. Lower activity of the samples containing small crystallites located in the pore volume at high temperatures was related to worse accessibility of active sites to the reation mixture.

Microplastics in the atmosphere of Ahvaz City, Iran

Airborne particulate matter(PM) with an aerodynamic size cutoff of 10 μm(PM_(10)) has been collected using a high volume air sampler at two locations(urban and residential) in the city of Ahvaz, Iran, for sixteen 24-hour periods over four months(late summer to early winter).Microplastics(MPs) in the PM were isolated after sample digestion and were subsequently characterised by established techniques. All MPs sampled(n = 322) were of a fibrous nature,with polyethylene terephthalate, nylon and polypropylene being the dominant polymers and consistent with textiles and fabrics as the principal source. Despite a distinct seasonality(temperature and wind) over the study period, the abundance, size and colour of the fibres exhibited no clear temporal trend, and no clear differences were observed between the two sites. Concentrations of MPs ranged from none detected to about 0.017/m^(3)(median = 0.0065/m^(3)) and are at the low end of ranges reported in the recent literature for various urban and remote locations. While some MPs may have a local origin, the weathering of other MPs and their acquisition of extraneous geosolids and salts suggests that long-range transport is also important. Back-trajectory calculations indicate that regional sources are mainly to the north and west of Ahvaz, but a southerly, maritime source is also possible in late autumn. Although concentrations of MPs in the atmosphere are well below those encountered in indoor air, further studies are required to elucidate their potential ecological impacts.

Trace elements and stable sulfur isotopes in plants of acid mine drainage area:Implications for revegetation of degraded land

The abundances of trace elements,a low pH of water and soil in areas impacted by the acid mine drainage(AMD)may cause an excessive uptake of potentially toxic elements and nutritional imbalances in plants.Metal-tolerant,native plants are used for revegetation of degraded mining areas.We established levels of selected trace elements and stable sulfur isotopes in the above-ground plant biomass collected in a mining area in south-central Poland.In 2016,20 samples of the most common species were collected from sites with a different influence of acid mine drainage and analyzed for trace elements by the inductively coupled plasma mass spectrometry technique.On the basis of the results obtained in 2016,the most contaminated site was selected for a more detailed study,in which sulfur contents and stable sulfur isotope ratios were determined together with trace elements in 17 samples.The results confirmed that the plants native to the AMD area efficiently accumulated trace elements,especially As and rare earth elements.Mosses showed the highest content of trace elements,but exhibited the lowest concentrations of sulfur accompanied by the highestδ34S values.It has been shown for the first time that stable sulfur isotope composition of AMD plants in south-central Poland is significantly depleted in the 34S isotope showing an averageδ34 S value of–10.5‰in comparison with positiveδ34S values in local vegetation growing outside the AMD area and in local precipitation.