The detection threshold of poly(allyl dyglycol carbonate), PADC, for C ions is determined as 55 eV/nm in stopping power, which is significantly higher than that for proton and He ions. The stopping ...power is not a universal parameter for expressing the detection threshold of PADC. A new physical parameter of Radial Electron Fluence around Ion Tracks, REFIT, is proposed to describe the detection threshold of PADC. It is defined as the number density of electrons passing through the surface of a cylinder of a certain radius that is co-axial with the trajectory. Furthermore, preliminary calculations are presently being performed using the Monte Carlo simulation code of Geant4-DNA. The values of the REFIT at the detection thresholds for each ion are of the same order. Several issues affecting implementation of the REFIT paramter are discussed. These include the effects of impact parameter relating to the initial locations of secondary electrons, the effects of electron attachment below the cut off energy of 7.4 eV and the necessity of a more physically realistic medium than water for Monte Carlo simultaions.
•Radial Electron Fluence around Ion Tracks, REFIT, is proposed as a new physical parameter for the detection threshold of PADC.•First calculation is made using Geant4-DNA toolkit.•Several future issues are discussed to improve the REFIT.
European harbours are known to contribute to air quality degradation. While most of the literature focuses on emissions from stacks or logistics operations, ship refit and repair activities are also ...relevant aerosol sources in EU harbour areas. Main activities include abrasive removal of filler and spray painting with antifouling coatings/primers/topcoats. This work aimed to assess ultrafine particle (UFP) emissions from ship maintenance activities and their links with exposure, toxicity and health risks for humans and the aquatic environment. Aerosol emissions were monitored during mechanical abrasion of surface coatings under real-world operating conditions in two scenarios in the Mallorca harbour (Spain). Different types of UFPs were observed: (1) highly regular (triangular, hexagonal) engineered nanoparticles (Ti-, Zr-, Fe-based), embedded as nano-additives in the coatings, and (2) irregular, incidental particles emitted directly or formed during abrasion. Particle number concentrations monitored were in the range of industrial activities such as drilling or welding (up to 5 ∗ 105/cm3, mean diameters <30 nm). The chemical composition of PM4 aerosols was dominated by metallic tracers in the coatings (Ti, Al, Ba, Zn). In vitro toxicity of PM2 aerosols evidenced reduced cell viability and a moderate potential for cytotoxic effects. While best practices (exhaust ventilation, personal protective equipment, dust removal) were in place, it is unlikely that exposures and environmental release can be fully avoided at all times. Thus, it is advisable that health and safety protocols should be comprehensive to minimise exposures in all types of locations (near- and far-field) and periods (activity and non-activity). Potential release to coastal surface waters of metallic engineered and incidental nanomaterials, as well as fine and coarse particles (in the case of settled dust), should be assessed and avoided.
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•Ship refit activities emit ultrafine and engineered nanoparticles in harbour areas.•Ultrafine and engineered nanoparticles impact human exposure.•In vitro assays evidenced moderate particle toxicity.•There is high potential for impacts to the aquatic coastal environment.•Improvements to safety protocols may minimise exposure and environmental release.
Archaeological recovery of chimpanzee Panda oleosa nut cracking tools at the Panda 100 (P100) and Noulo sites in the Taï Forest, Côte d'Ivoire, showed that this behavior is over 4000 years old, ...making it the oldest known evidence of non-human tool use. In 2002, the first report on the lithic material from P100 was directly compared to early hominin stone tools, highlighting their similarities and proposing the name ‘Pandan’ for the chimpanzee material. Here we present an expanded and comprehensive technological, microscopic, and refit analysis of the late twentieth century lithic assemblage from P100. Our re-analysis provides new data and perspectives on the applicability of chimpanzee nut cracking tools to our understanding of the percussive behaviors of early hominins. We identify several new refit sets, including the longest (>17 m) hammerstone transport seen in the chimpanzee archaeological record. We provide detailed evidence of the fragmentation sequences of Panda nut hammerstones, and characterize the percussive damage on fragmented material from P100. Finally, we emphasize that the chimpanzee lithic archaeological record is dynamic, with the preservation of actual hammerstones being rare, and the preservation of small broken pieces more common. P100 – the first archaeological chimpanzee nut cracking lithic assemblage – provides a valuable comparative sample by which to identify past chimpanzee behavior elsewhere, as well as similar hominin percussive behavior in the Early Stone Age.
In this study, we represent the track response data of poly (allyl diglycol carbonate) (PADC) using the number of interactions with the stopping medium induced by secondary electrons. The Number of ...Interactions induced by Secondary Electrons (NISE) is calculated using a Monte Carlo simulation code in Geant4-DNA. The description of the track response data given by NISE is improved compared with those proposed previously based on the stopping power and Radial Electron Fluence around Ion Tracks (REFIT). We also simulate the removal cross sections of the carbonate ester bond in PADC irradiated with protons and heavy ions (He, C, and Fe) based on the NISE. A radiation-oxidation kinetics model is combined with the estimation obtained in the present study. Discrepancies are found between the experimental results and our present simulation even after applying the radiation-oxidation kinetics model in the low stopping power region (<10 eV). Our results demonstrate that the interactions among electrons lying within the low-energy region (<7.4 eV) and the energy dependence of the yields due to bond breaks are crucial for obtaining more accurate estimation.
•Number of interactions induced by secondary electrons (NISE) calculated.•Track response data for protons, and He and C ions expressed by NISE.•Track core size also estimated using NISE.
This paper expands upon the preliminary refit analysis of the NW area of unit TD10.1 at Gran Dolina (Sierra de Atapuerca, Burgos, Spain) (López-Ortega et al., 2011). The refit study described here ...has been conducted on the quartz and quartzite assemblage recovered from unit TD10.1, consisting of a total of 4302 artefacts (709 quartz and 3593 quartzite pieces). Following the previously established methodological protocol, we found additional elements associated with already known connections as well as new refits in quartz and quartzite. The association between refits and raw material units (RMUs) has allowed us to distinguish specific concentrations and spatial clusters that could correspond to singular knapping events, and to identify the movements of pieces within the same raw material unit outside of their clusters, which could point to the use of these artefacts.
These results, together with the presence of artefacts of every phase of the chaîne opératoire, point to developed knapping activities carried in the settlement and the areas where they took place. A new interdisciplinary study will identify the role played by intentionally moved pieces.
•Detection thresholds of PET for B, C, N and O ions are determined using Radial Electron Fluence around Ion Tracks (REFIT).•Track response curve expressed by REFIT is compared to other physical ...parameters such as the stopping power, Zeff/β and REL.•Advantage for the use of REFIT is indicated.
We try to establish a universal description for the response curve (i.e., relation between the track registration sensitivity and a physical parameters) of polyethylene terephthalate (PET) as a polymeric nuclear track detector. To do so, we adopt a newly developed physical concept Radial Electron Fluence around Ion Tracks (REFIT) using a Monte Carlo simulation in Geant4-DNA, which has been defined as the number of secondary electrons passing through a cylindrical surface that is co-axial to the ion path. We find 11% disagreement for the description of the detection thresholds, from which etch pits start their evolutions when the value of REFIT at a radius of 4.0 nm is used. However, compared to other physical parameters, the REFIT offers improved parameters for the detection thresholds of PET, such as the stopping power, Zeff/β and RELω0=1000 eV. Finally, we discuss future issues affecting implementation of REFIT.
REFIT of the SEA Directive Čavoški, Aleksandra
Environmental law review,
06/2020, Volume:
22, Issue:
2
Journal Article
Open access
The REFIT evaluation concluded that the SEA Directive still remains fit for purpose. It is successfully applied in different social, economic and administrative settings and it acts as a flexible ...procedural tool in pursuit of important environmental objectives. Although there are inevitable differences between member states in implementing the Directive, the evaluation exposed some of the common challenges facing all member states in implementing different aspects of the Directive in practice. They include difficulties resulting from the lack of clarity of the Directive’s scope, the timing of the SEA, the preparation of environmental reports and a lack of better public engagement.
Contemporaneity of spatially distinct activity areas at prehistoric sites is often inferred based on lithic refit connections alone. These connections are, in addition, only rarely discussed in ...detail, nor are they explicitly subjected to any form of critical assessment. In this paper, we present a combined use of Bayesian modeling of
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C-dates, raw material characterizations and lithic refitting to investigate the occurrence of interconnected artefact clusters at the Belgian Mesolithic site of Kerkhove. Besides this, a set of parameters is presented that is employed to control the reliability of the refit connections. The three proxies applied in this paper suggest that the Early Mesolithic occupation of the site was organized as two diachronic and more or less parallel alignments of artefact clusters. Based on the lithic refitting results, two scenarios can be considered to explain the formation histories of these linear arrangements. The individual artefact clusters incorporated within them were either occupied in a strictly contemporaneous manner or in a (partly) sequential manner.
Wind energy is present in many countries throughout the world. The main types of wind sales in electricity markets are via regulated tariffs or pool-based markets. Production companies choose ...cost-effective options for selling wind energy, and some markets, like the Irish electricity market, use regulated tariffs to remunerate wind production. This paper aims to provide some answers to explain what effect wind offers may have in an electricity market if wind power producers participated in the day-ahead market without receiving any premium or aid. A price-maker optimization model is used to detect its effect on prices. The model encompasses energy offers by other technologies using residual demand curves and detailed modeling of wind imbalances. It is observed that wind acting as price-maker reduces electricity prices and the imbalance penalties help the system operator to reduce imbalances. A realistic case study using data from the Irish electricity market illustrates the methodology used comparing the effect of imbalance penalties in the models in terms of profit and total imbalance of the system.
Rapid global growth in consumption of limited fossil fuels parallel to global population growth and environmental concerns on sustainability of the current energy resources, led engineers and ...scientists into the search for alternative resources of energy. The goal of this search is to meet human energy needs, while mitigate the potential drastic effects of fossil fuels consumption. Tidal energy, due to its high level of consistency and predictability, is one of the feasible and promising type of renewable energy for future development and investment. The goal of this study is to present a comprehensive insight into development of tidal stream energy farms in Iran. In the current work based on numerical simulations three potential tidal sites have been identified in Persian Gulf and Oman Sea: Khowran Strait, Hengam Island and Greater-Tunb Island. Then, according to thirteen specified attributes, technical evaluation of three above mentioned sites has been performed. According to these evaluations Hengam and Greater-Tunb Islands showed more potentials for implementation of a commercial scale tidal turbine farm. Further analyses proved that Levelized Cost Of Energy (LCOE) for Hengam and Greater-Tunb Islands is 182.25 and 221.51 GBP/MWh respectively. With these LCOE values and current Renewable Energy Feed in Tariff (REFiT) rate in Iran, it is expected that the return of investment period in Hengam and Greater-Tunb Islands to be 18.77 and 23.79 years respectively. These values dictate that current REFiT rates have to be increased to attract private sector for investment in this field and to make tidal current energy more competitive among other types of energies.
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