Effects of Vacancies near Substitutional Implants on Trapping and Desorption of Helium - A Simulation

Trapping of He by vacancies and drainage of He from substitutional implants (Ag and Kr in W) to nearby vacancies are investigated using static lattice calculations. The calculations indicate that drainage of He will occur to vacancies within a radius of 2.5 lattice units from the implant. Furthermore the trapping probability of substitutional and interstitial random walkers on a bcc lattice by substitutional traps or vacancies is calculated. When implantation-produced vacancies are present in the vicinity of the observed trap a shielding effect occurs. Trapping constants are calculated with two random walk models for both the unshielded and the shielded defect. For the latter several configurations were taken. The results show that shielding of a defect by one vacancy at a distance of three lattice units leads already to a reduction of He trapping by that defect of 30% to 40%.

Light levitated geostationary cylindrical orbits are feasible

This paper discusses a new family of non-Keplerian orbits for solar sail spacecraft displaced above or below the Earth's equatorial plane. The work aims to prove the assertion in the literature that displaced geostationary orbits exist, possibly to increase the number of available slots for geostationary communications satellites. The existence of displaced non-Keplerian periodic orbits is ¯rst shown analytically by linearization of the solar sail dynamics around a geostationary point. The full displaced periodic solution of the non-linear equations of motion is then obtained using a Hermite-Simpson collocation method with inequality path constraints. The initial guess to the collocation method is given by the linearized solution and the inequality path constraints are enforced as a box around the linearized solution. The linear and nonlinear displaced periodic orbits are also obtained for the worst-case Sun-sail orientation at the solstices. Near-term and high-performance sails can be displaced between 10 km and 25 km above the Earth's equatorial plane during the summer solstice, while a perforated sail can be displaced above the usual station-keeping box (75 £ 75 km) of nominal geostationary satellites. Light-levitated orbit applications to Space Solar Power are also considered

Consultancy haalbaarheid Klimrekscherm

Deze haalbaarheidstudie heeft als doel de mogelijkheden van het klimrek systeem in de glastuinbouw in kaart te brengen in een semi-gesloten teelt concept teneinde te komen tot energiebesparing, productieverhoging, betere kwaliteit, betere CO2 benutting en minder uitval ten gevolge van vochtproblemen door een te hoge RV

What determines success in Initial Coin Offerings?

In this paper, we analyse the determinants of success for 630 ICOs performed between August 2015 and December 2017. We find evidence that ICOs are more successful in raisi

What determines success in initial coin offerings?

We analyse the determinants of success for 630 ICOs undertaken from August 2015 up until the end of December 2017, a period in which the market for ICOs grew to an unprecented level. We find evidence that ICOs are more successful in raising funding when they disclose more information to investors (i.e. have a higher profile rating), have a higher quality rating by cryptocurrency experts, have a pre-ICO GitHub repository, organise a presale, refrain from offering bonus schemes, have shorter planned token sale durations and have a larger project team. ICOs that disclose more information to investors and that have a higher quality rating at the time of the campaign show stronger ex-post performance. Longer-term project success is positively impacted by having a pre-ICO GitHub repository, a shorter planned token sale duration and having a larger project team at the time of the ICO, although these results depend on the ex-post success measure used. We conclude that for entrepreneurs it is important to make an ICO as transparent as possible and that profile and expert ratings are a valuable means to overcome the information asymmetry problems associated with token sales

The hidden cost of disturbance: Eurasian Oystercatchers (Haematopus ostralegus) avoid a disturbed roost site during the tourist season

Disturbance may impact individual birds and ultimately bird populations. If animals avoid disturbed sites this may prevent them from being disturbed directly but may also negatively impact their movement patterns and energy budgets. Avoidance is, however, challenging to study, because it requires following individuals over large spatial scales in order to compare their movement rates between sites in relation to spatiotemporal variation in disturbance intensity. We studied how 48 GPS-tracked non-breeding Eurasian Oystercatchers Haematopus ostralegus used two neighbouring roost sites in the Wadden Sea. One roost site is highly influenced by seasonal recreational disturbance whereas the other is an undisturbed sandbar. We analysed roost choice and the probability of moving away from the disturbed roost site with regard to a seasonal recreation activity index, weekends and night-time. Oystercatchers often chose to roost on the undisturbed site, even if they were foraging closer to the disturbed roost. The probability that Oystercatchers chose to roost on the disturbed site was negatively correlated with the recreation activity index and was lowest in the tourist season (summer and early autumn), indicating that birds used the site less often when recreation levels were high. Furthermore, the probability that birds moved away from the disturbed site during high tide was positively correlated with the recreation activity index. The choice to roost on the undisturbed site implies that birds must fly an additional 8 km during one high-tide period, which equates to 3.4% of daily energy expenditure of an average Oystercatcher. Our study tentatively suggests that the costs of avoidance may outweigh the energetic cost of direct flight responses and hence that avoidance of disturbed sites requires more attention in future disturbance impact studies. Nature managers should evaluate whether high-quality undisturbed roosting sites are available near foraging sites, and in our case closing of a section of the disturbed site during high tides in the tourist season may mitigate much disturbance impact

Diverging business strategies towards climate change : a USA-Europe comparison for four sectors of industry

The research project has investigated what strategies specific sectors of industry develop to limit greenhouse gas emissions. In an USA-Europe co-operation, researchers have analysed emerging climate strategies in the oil industry, the automobile industry, the chemical industry and the bank and insurance sector. These sectors are the most important players in the climate policy debate. Special attention has been paid to the questions whether strategies of EU based corporations differ systematically from USA based corporations. Results show rather sectorial specific developments. In most sectors, i.e. oil, automobile and banks, European corporations generally tend to have more advanced policies than their USA counterparts, but this does not apply to chemical companies. Corporate strategies appear to be highly determined by a combination of market situation in the home country and of access to alternative technologies. Objective of the study was to provide information of relevance to the COP (Sixth Session of the UNFCCC Conference of the Parties) 2000 conference, November 2000 in The Hague

Spatiotemporal variation in disturbance impacts derived from simultaneous tracking of aircraft and shorebirds

Assessing the impacts of disturbance over large areas and long time periods is crucial for nature management, but also challenging since impacts depend on both wildlife responses to disturbance and on the spatiotemporal distribution of disturbance sources. Combined tracking of animals and disturbance sources enables quantification of wildlife responses as a function of the distance to a disturbance source. We provide a framework to derive such distance–response curves and combine those with disturbance source presence data to quantify energetic costs of disturbance at a landscape scale. We tracked 90 Eurasian Oystercatchers Haematopus ostralegus and all aircraft in a military training area in the Dutch Wadden Sea. We quantified distance–response curves estimating flight probability and additional displacement for five types of aircraft activities, by comparing bird movement prior to aircraft presence with movement during aircraft presence. We then used the distance–response curves to map mean and variation in additional daily energy expenditure due to cumulative aircraft disturbance across the landscape for a 700-day period. Flight probability and displacement responses differed strongly among aircraft activities and decreased from transport aeroplanes, through bombing jets, helicopters, jets to small civil aeroplanes. Since the most disturbing aircraft activities were also the rarest ones, mean additional daily energy expenditure did not exceed 0.25%. However, days with substantial (>1%) additional expenditure occurred between 0.1% and 3.7% of all days across high-tide roosts in the tidal basin. Notably, expenditure particularly spiked on days with transport aeroplane activity (up to 8.5%). Synthesis and applications. We quantified cumulative energetic flight costs due to aircraft disturbance and found that these were low and unlikely to impact survival of oystercatchers in our study area. Our results provide evidence that the legal minimum flight height of 450 m for small civil aeroplanes effectively limits the disturbance of oystercatchers. Mitigation should focus on limiting the number of days when disturbance has a high impact by reducing rare but highly disturbing activities, especially transport aeroplanes. Our approach can be applied to other species and disturbance sources that are automatically tracked, for example boats and walkers, ultimately to quantify the entire anthropogenic disturbance landscape