| 1. |
- Kalhori, S., et al.
(författare)
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Resonant ion-pair formation in electron collisions with rovibrationally cold H-3(+)
- 2004
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 69:2, s. 022713-
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical cross sections for the resonant ion-pair formation (RIP) in electron collisions with rovibrationally cold H-3(+) ions are presented. Absolute cross sections for the RIP process producing H- ions are measured for center-of-mass energies between 2-20 eV using the CRYRING, heavy-ion storage ring. Theoretical cross sections are obtained using wave-packet propagation on both one- and two-dimensional models of relevant diabatic-potential energy surfaces and couplings of H-3(+) and H-3.
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| 2. |
- Al-Khalili, A, et al.
(författare)
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Dissociative recombination cross section and branching ratios of protonated dimethyl disulfide and N-methylacetamide
- 2004
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 121:12, s. 5700-5708
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Tidskriftsartikel (refereegranskat)abstract
- Dimethyl disulfide (DMDS) and N-methylacetamide are two first choice model systems that represent the disulfide bridge bonding and the peptide bonding in proteins. These molecules are therefore suitable for investigation of the mechanisms involved when proteins fragment under electron capture dissociation (ECD). The dissociative recombination cross sections for both protonated DMDS and protonated N-methylacetamide were determined at electron energies ranging from 0.001 to 0.3 eV. Also, the branching ratios at 0 eV center-of-mass collision energy were determined. The present results give support for the indirect mechanism of ECD, where free hydrogen atoms produced in the initial fragmentation step induce further decomposition. We suggest that both indirect and direct dissociations play a role in ECD.
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| 3. |
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| 4. |
- Geppert, W. D., et al.
(författare)
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Dissociative recombination of N2H+ : Evidence for fracture of the N-N bond
- 2004
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 609:1, s. 459-464
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of N2H+ using the CRYRING ion storage ring. It has been found that the channel N2H+ + e(-) --> N-2 + H accounts for only 36% of the total reaction and that the branching into the other exoergic pathway, N2H+ + e(-) --> NH + N, consequently amounts to 64%. The cross section of the reaction could be fitted by the expression sigma = (2.4 +/- 0.4) x 10(-16) E-1.04 +/- 0.02 cm(2), which leads to a thermal reaction rate of k(T) = (1.0 +/- 0.2) x 10(-7)(T/300)(-0.51 +/- 0.02) cm(3) s(-1), in favorable agreement with previous flowing afterglow Langmuir probe measurements at room temperature, although our temperature dependence is very different. The implications of these measurements for the chemistry of interstellar clouds are discussed. A standard model calculation for a dark cloud predicts a slight increase of N2H+ in the dark clouds but a five- to sevenfold increase of the NH concentration as steady state is reached.
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| 5. |
- Pitz-Paal, R., et al.
(författare)
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Concentrating solar power in Europe, the Middle East and North Africa: Achieving its potential
- 2012
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Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 33
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Konferensbidrag (refereegranskat)abstract
- Concentrating solar power (CSP) is a commercially available renewable energy technology capable of harnessing the immense solar resource in Southern Europe, the Middle East and North Africa (the MENA region), and elsewhere. This paper summarises the findings of a study by the European Academies Science Advisory Council which has examined the current status and development challenges of CSP, and consequently has evaluated the potential contribution of CSP in Europe and the MENA region to 2050. It identifies the actions that will be required by scientists, engineers, policy makers, politicians, business and investors alike, to enable this vast solar resource to make a major contribution to establishing a sustainable energy system. The study concludes that cost reductions of 50-60% in CSP electricity may reasonably be expected in the next 10-15 years, enabling the technology to be cost competitive with fossil-fired power generation at some point between 2020 and 2030. Incorporation of storage delivers added value in enabling CSP to deliver dispatchable power. Incentive schemes will be needed in Europe and MENA countries to enable this point to be achieved. Such schemes should reflect the true value of electricity to the grid, effectively drive R&D, and ensure transparency of performance and cost data.
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| 6. |
- Geppert, W D, et al.
(författare)
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Extraordinary branching ratios in astrophysically important dissociative recombination reactions
- 2004
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Ingår i: Faraday discussions. - : Royal Society of Chemistry (RSC). - 1359-6640 .- 1364-5498. ; 127, s. 425-437
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Tidskriftsartikel (refereegranskat)abstract
- Branching ratios of the dissociative recombination reactions of the astrophysically relevant ions DCO+, N2H+ and DOCO+ ( as substitute for HOCO+) have been measured using the CRYRING storage ring at the Manne Siegbahn Laboratory at the University of Stockholm, Sweden. For DCO+, the channel leading to D and CO was by far the most important one ( branching ratio 0.88), only small contributions of the CD+O and OD+C product pathways ( branching ratios 0.06 each) were recorded. In the case of N2H+ the surprising result of a break-up of the N-N bond to N and NH ( branching ratio 0.64) was found with the branching ratio of the N-2+H product channel therefore displaying a branching ratio of only 0.36. In the case of DOCO+, the three-body break-up into D+O+CO dominated ( branching ratio 0.68), whereas the contribution of the CO2+H channel was only minute (0.05). The remaining share ( branching ratio 0.27) was taken by the pathway leading to OH+CO. For the dissociative recombination of N2H+ and DOCO+ also absolute reaction cross sections were obtained in the collisional energy range between 0 and 1 eV. From these cross sections it was possible to work out the thermal rate constants, which were found to be k(T) = 1.0 +/- 0.1 x 10(-7) (T/300 K)(-0.51 +/- 0.02) cm(3) s(-1) and k(T) = 1.2 +/- 0.1 x 10(-6) (T/300 K)(-0.64 +/- 0.02) cm(3) s(-1) for N2H+ and DOCO+, respectively.
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| 7. |
- Krokene, Paal, et al.
(författare)
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Pest risk categorization – New plant health regulations for Norway : Scientific Opinion of the Panel on Plant Health of the Norwegian Scientific Committee for Food and Environment
- 2021
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Rapport (refereegranskat)abstract
- In an ongoing effort to renew Norwegian regulations related to plants and measures against plant pests, the Norwegian Food Safety Authority asked The Norwegian Scientific Committee for Food and Environment (VKM) which of the currently regulated pests that should still be regulated (either as a quarantine pest (QP) or a regulated non-quarantine pest (RNQP) for Norway), and whether there are any species that should be deregulated. Following such a risk categorization process the Norwegian Food Safety Authority will determine if pest risk assessments (PRA’s) should be performed for quarantine pests. International trade regulations define quarantine pests (QPs) as pests of potential economic importance to an area that are not yet present, or are present but not widely distributed and are subject to official control. A regulated non-quarantine pest (RNQP) is a pest whose presence in plants for planting affects the intended use of those plants with an economically unacceptable impact and which is therefore subject to official control within the territory of the importing contracting party and regulated in international trade. In this report VKM presents an overview of the pest categorisation of some of the pests regulated in the current Norwegian regulation and concludes on whether each pest should be regulated as a potential QP, RNQP or none of these categories for Norway. The pest categorisation process – the process of determining whether a pest has or has not the characteristics of a QP or RNQP – has been done using the FinnPRIO model. The FinnPRIO model is a pest risk ranking tool that uses a hypervolume approach carry out quick, semiquantitative expert assessments and that allows a high number of pest risk categorizations to be done cost-effectively and in a short period of time. In total 33 pests were assessed as per request from the Norwegian Food Safety Authority. Of those 33 pests VKM suggests that the vast majority – 32 pests – are kept as a QPs for Norway. However, one pest, the cherry leafroll nepovirus (EPPO code CLRV00), fulfils the requirements for being a RNQP since it is most likely present in Norway already. Furthermore, one organism, the flatworm Arthurdendyus triangulates (ARDDTR), is suggested to not be regulated as QP or RNQP. This pest does not fulfil the requirements for being a QP since it would probably not cause direct damage to plants if it established in Norway. Also, it does not fulfill the requirements for being a regulated non-quarantine pest(RNQP) since its potential presence in plants for planting does not directly affect the intended use of those plants with an economically unacceptable impact.
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| 9. |
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| 10. |
- Stenberg, Johan A., et al.
(författare)
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Pest risk assessment of selected Epitrix species : Scientific Opinion of the Panel on Plant Health of the Norwegian Scientific Committee for Food and Environment
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Epitrix is a taxonomically complex genus, with 162 described species all over the world, and most likely many more undescribed species. Due to taxonomic difficulties identifying the species, there is considerable uncertainty regarding which species that feed on cultivated crops. At least 13 Epitrix species are known to damage the tubers of potato, which is the crop of concern in northern Europe. At least five of those Epitrix species (E. hirtipennis, E. fasciata, E.cucumeris, E. papa and E. pubescens) have established themselves outside their native range, spurring concerns that they may spread further and potentially cause damage in new areas where potato is cultivated. It is unknown how most of these species have moved from country to country, but there have been several interceptions of unknown Epitrix species in shipments of ware potatoes.
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