| 1. |
- Persson, Bertil R, et al.
(författare)
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Radioactivity exploration from the Arctic to the Antarctic. Part 3. The SWEDARP expedition Oct 1988 – April 1989
- 2015
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2015:004, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Antarctic Research Expedition named “SWEDARP” was performed during October 1988 through April 1989. The aim of our project was to study the radioactivity in air and water from Gothenburg to the Antarctic. Between Gothenburg and the Equator, the average activity concentration of 7Be in air was 4.3 ± 0.7 mBq/m3. The activity concentration of 7Be in the South Atlantic down to Antarctica varied between 1.3 and 1.7 with an average of 1.5 ± 0.8 mBq/m3. The average activity concentration of 210Pb in air during autumn 1988 on the route Gothenburg- Montevideo was about 290±270 micro-Bq/m3 and on the return in spring 1989 it was about 230±140 micro-Bq/m3. At the Equator, the average activity concentration of 210Pb in November 1988 was about 630±170 and in April 1989 about 260±210 microBq/m3. In the South Atlantic down to Antarctica during February-March 1989, the activity concentration of 210Pb varied between 11 and 58 micro-Bq/m3. The average activity concentration of 210Po in air during the route Gothenburg- Montevideo in 1988 was about 63±58, and on the return, it was about 60±44 The Swedish Antarctic Research Expedition named “SWEDARP” was performed during October 1988 through April 1989. The aim of our project was to study the radioactivity in air and water from Gothenburg to the Antarctic. Between Gothenburg and the Equator, the average activity concentration of 7Be in air was 4.3 ± 0.7 mBq/m3. The activity concentration of 7Be in the South Atlantic down to Antarctica varied between 1.3 and 1.7 with an average of 1.5 ± 0.8 mBq/m3. The average activity concentration of 210Pb in air during autumn 1988 on the route Gothenburg- Montevideo was about 290±270 micro-Bq/m3 and on the return in spring 1989 it was about 230±140 micro-Bq/m3. At the Equator, the average activity concentration of 210Pb in November 1988 was about 630±170 and in April 1989 about 260±210 microBq/m3. In the South Atlantic down to Antarctica during February-March 1989, the activity concentration of 210Pb varied between 11 and 58 micro-Bq/m3. The average activity concentration of 210Po in air during the route Gothenburg- Montevideo in 1988 was about 63±58, and on the return, it was about 60±44 micro-Bq/m3. At the Equator, the average activity concentration in Nov 1988 was about 132±45, and in April 1989 about 70±60 micro-Bq/m3. The activity concentration of 210Po in the South Atlantic down to Antarctica during February-March 1989 varied between 6 and 14 micro-Bq/m3. The inventory (Bq.m-2) of various deposited ratio nuclides, measured in moss, lichen, soil and lake sediments was: 280 ±110 for 210Pb (excess); 155 ± 95 for 137Cs, 4.6 ± 2.6 for 239+240Pu, 1.6 ± 1.0 for 241Am and, 0.95± 0.5 for 238Pu. 137Cs activity concentration (Bq.m-3) in surface waters samples along the route of the SWEDARP expedition was about 3 Bq.m-3 above 20 °N , decreased to about 2 Bq.m-3 between 20 °N and 40 °S where it decrease to about 1 Bq.m-3 , and at 55 °S (e) there is a further decrease to about 0.3 Bq.m-3. Radio-Caesium, which originates from atmospheric nuclear weapons tests carried out in the late 1950's and the early 1960's shows a long residence time in surface waters of the North and South Atlantic Oceans with half-time, corrected for physical decay estimated to be more than bout 100 years. Concentration factor for 137Cs estimated to 15000 for fish in the Antarctic is much higher than the value of 500 given by The IAEA 1985. Concentration factors for MacroAlgea/Water, was found to be about 1800 in the Antarctic compared to 100 the Arctic. The 239+240Pu activity concentrations in the surface water was about 8 mBq.m-3 in the latitude band 5°-25 °N , about 3 mBq.m-3 in the latitude band 25-5 °N; and about 1,5 mBq.m-3 in the latitude band 0 °S-60 °S. Plutonlum-238 activity was measured in a few water samples from the southern hemisphere with activity ratio of 238Pu to 239+240Pu in the range of 0.14-0.22. Plutonium isotopes 239+240Pu from atmospheric nuclear weapons tests has a low half-life of 7-8 years due to the higher affinity to sinking particles for Pu than Cs. In the southern hemisphere, 238Pu was found as the result of the 1964 burn-up of a satellite in the atmosphere over the Mozambique Channel. The Average activity concentrations (Bq/kgdw,) of 137Cs are in flesh of seals 2.5, penguins 0.2 and, fish 2.5 in liver of seals 0.6 and penguins 0.7 and in kidneys of seals 0.5. The Average activity concentrations (Bq/kgdw) of 210Po are in flesh of seals 8, penguins 4 and, fish 7, in liver of seals 110 and penguins 43 and, fish 5, and in kidneys of seals 91 and of penguins 43. The Average activity concentrations (Bq/kgdw,) of 210Pb are in flesh of seals 0,3, penguins 0,2, and fish 0.6, in liver of seals 4 and penguins 1 and, fish 1, and in kidneys of seals 1 and of penguins 1. The Average activity concentration of 137Cs in samples of Krill is about 1.7 Bq/kgdw of 210Po and 210Pb are in samples of Amphipods, 87 and 1.4 Bq/kgdw respectively. Radio-Caesium, which originates from atmospheric nuclear weapons tests carried out in the late 1950's and the early 1960's shows a long residence time in surface waters of the North and South Atlantic Oceans with half-time, corrected for physical decay estimated to be more than bout 100 years. Plutonium isotopes 239+240Pu from atmospheric nuclear weapons tests has a low half-life of 7-8 years due to the higher affinity to sinking particles for Pu than Cs. In the southern hemisphere, 238Pu was found as the result of the 1964 burn-up of a satellite in the atmosphere over the Mozambique Channel.Bq/m3. At the Equator, the average activity concentration in Nov 1988 was about 132±45, and in April 1989 about 70±60 micro-Bq/m3. The activity concentration of 210Po in the South Atlantic down to Antarctica during February-March 1989 varied between 6 and 14 micro-Bq/m3. The inventory (Bq.m-2) of various deposited ratio nuclides, measured in moss, lichen, soil and lake sediments was: 280 ±110 for 210Pb (excess); 155 ± 95 for 137Cs, 4.6 ± 2.6 for 239+240Pu, 1.6 ± 1.0 for 241Am and, 0.95± 0.5 for 238Pu. 137Cs activity concentration (Bq.m-3) in surface waters samples along the route of the SWEDARP expedition was about 3 Bq.m-3 above 20 °N , decreased to about 2 Bq.m-3 between 20 °N and 40 °S where it decrease to about 1 Bq.m-3 , and at 55 °S (e) there is a further decrease to about 0.3 Bq.m-3. Radio-Caesium, which originates from atmospheric nuclear weapons tests carried out in the late 1950's and the early 1960's shows a long residence time in surface waters of the North and South Atlantic Oceans with half-time, corrected for physical decay estimated to be more than bout 100 years. Concentration factor for 137Cs estimated to 15000 for fish in the Antarctic is much higher than the value of 500 given by The IAEA 1985. Concentration factors for MacroAlgea/Water, was found to be about 1800 in the Antarctic compared to 100 the Arctic. The 239+240Pu activity concentrations in the surface water was about 8 mBq.m-3 in the latitude band 5°-25 °N , about 3 mBq.m-3 in the latitude band 25-5 °N; and about 1,5 mBq.m-3 in the latitude band 0 °S-60 °S. Plutonlum-238 activity was measured in a few water samples from the southern hemisphere with activity ratio of 238Pu to 239+240Pu in the range of 0.14-0.22. Plutonium isotopes 239+240Pu from atmospheric nuclear weapons tests has a low half-life of 7-8 years due to the higher affinity to sinking particles for Pu than Cs. In the southern hemisphere, 238Pu was found as the result of the 1964 burn-up of a satellite in the atmosphere over the Mozambique Channel. The Average activity concentrations (Bq/kgdw,) of 137Cs are in flesh of seals 2.5, penguins 0.2 and, fish 2.5 in liver of seals 0.6 and penguins 0.7 and in kidneys of seals 0.5. The Average activity concentrations (Bq/kgdw) of 210Po are in flesh of seals 8, penguins 4 and, fish 7, in liver of seals 110 and penguins 43 and, fish 5, and in kidneys of seals 91 and of penguins 43. The Average activity concentrations (Bq/kgdw,) of 210Pb are in flesh of seals 0,3, penguins 0,2, and fish 0.6, in liver of seals 4 and penguins 1 and, fish 1, and in kidneys of seals 1 and of penguins 1. The Average activity concentration of 137Cs in samples of Krill is about 1.7 Bq/kgdw of 210Po and 210Pb are in samples of Amphipods, 87 and 1.4 Bq/kgdw respectively. Radio-Caesium, which originates from atmospheric nuclear weapons tests carried out in the late 1950's and the early 1960's shows a long residence time in surface waters of the North and South Atlantic Oceans with half-time, corrected for physical decay estimated to be more than bout 100 years. Plutonium isotopes 239+240Pu from atmospheric nuclear weapons tests has a low half-life of 7-8 years due to the higher affinity to sinking particles for Pu than Cs. In the southern hemisphere, 238Pu was found as the result of the 1964 burn-up of a satellite in the atmosphere over the Mozambique Channel.
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| 2. |
- Anderson, Leif G., et al.
(författare)
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The effect of the Siberian tundra on the environment of the shelf seas and the Arctic Ocean
- 1999
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Ingår i: Ambio. - 0044-7447. ; 28:3, s. 270-280
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Tidskriftsartikel (refereegranskat)abstract
- The Tundra Ecology -94 expedition investigated inflow of inorganic and organic carbon to the shelf seas by river runoff, and its transformation by biochemical processes in seawater and sediment. In addition, anthropogenic radionuclides, 137Cs, 90Sr, and 239,240Pu, were studied in water and sediments. The distribution of dissolved inorganic carbon indicates that the majority of the Ob and Yenisey discharges flow into the Laptev Sea before entering the central Arctic Ocean. The sediment study shows that there is a marked difference in benthic oxygen uptake, efflux of dissolved inorganic carbon and nutrients between localities. 137Cs activity from the Chernobyl accident is 30% in the Barents, Kara, and Laptev Seas. 137Cs increased from 5-8 Bq m-3 in Barents Sea, 5-13 Bq m-3 in the Kara Sea to 8-15 Bq m-3 in the Laptev Sea, but with locally low concentrations at the river mouths. Corresponding values for 90Sr were 2.5, 3, and 4 Bq m-3, respectively.
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| 3. |
- Andersson, Anton, et al.
(författare)
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Ground granulated iron silicate slag as supplementary cementitious material: Effect of prolonged grinding and granulation temperature
- 2023
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Ingår i: Cleaner Materials. - : Elsevier. - 2772-3976. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The metallurgical and cement industries contribute significantly to anthropogenic carbon dioxide emissions. Utilizing oxidic by-products from the metallurgical industry as supplementary cementitious materials (SCMs) can improve resource efficiency and reduce emissions from cement production. Iron silicate copper slags have been studied as SCMs, but mainly in systems where Portland cement is used as an activator. There is limited research on the inherent reactivity of the slag under changing processing conditions. The present study offers insight into the effect of granulation temperature and grinding on the inherent reactivity of an industrially produced iron silicate copper slag. The results showed that granulation temperature had an insignificant effect on reactivity, while grinding generated substantial improvements. The latter effect was concluded to stem from the increased specific surface area, increased number of sites for nucleation and growth of hydrates, and changes in the inherent reactivity owing to structural changes induced by the grinding.
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| 4. |
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| 5. |
- Aquilante, Francesco, et al.
(författare)
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Cholesky decomposition-based multiconfiguration second-order perturbation theory (CD-CASPT2) : application to the spin-state energetics of Co-III(diiminato)(NPh).
- 2008
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Ingår i: Journal of Chemical Theory and Computation. - : American Chemical Society (ACS). - 1549-9618 .- 1549-9626. ; 4:5, s. 694-702
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure and low-lying electronic states of a Co-III(diiminato)(NPh) complex have been studied using mulficonfigurational wave function theory (CASSCF/CASPT2) The results have been compared to those obtained with density functional theory. The best agreement with ab initio results is obtained with a modified B3LYP functional containing a reduced amount (15%) of Hartree-Fock exchange. A relativistic basis set with 869 functions has been employed in the most extensive ab initio calculations, where a Cholesky decomposition technique was used to overcome problems arising from the large size of the two-electron integral matrix. It is shown that this approximation reproduces results obtained with the full integral set to a high accuracy, thus opening the possibility to use this approach to perform multiconfigurational wave-function-based quantum chemistry on much larger systems relative to what has been possible until now.
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| 6. |
- Aquilante, Francesco, et al.
(författare)
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Software news and update MOLCAS 7 : The Next Generation
- 2010
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Ingår i: Journal of Computational Chemistry. - : Wiley. - 0192-8651 .- 1096-987X. ; 31:1, s. 224-247
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Forskningsöversikt (refereegranskat)abstract
- Some of the new unique features of the MOLCAS quantum chemistry package version 7 are presented in this report. In particular, the Cholesky decomposition method applied to some quantum chemical methods is described. This approach is used both in the context of a straight forward approximation of the two-electron integrals and in the generation of so-called auxiliary basis sets. The article describes how the method is implemented for most known wave functions models: self-consistent field, density functional theory, 2nd order perturbation theory, complete-active space self-consistent field multiconfigurational reference 2nd order perturbation theory, and coupled-cluster methods. The report further elaborates on the implementation of a restricted-active space self-consistent field reference function in conjunction with 2nd order perturbation theory. The average atomic natural orbital basis for relativistic calculations, covering the whole periodic table, are described and associated unique properties are demonstrated. Furthermore, the use of the arbitrary order Douglas-Kroll-Hess transformation for one-component relativistic calculations and its implementation are discussed. This section especially focuses on the implementation of the so-called picture-change-free atomic orbital property integrals. Moreover, the ElectroStatic Potential Fitted scheme, a version of a quantum mechanics/molecular mechanics hybrid method implemented in MOLCAS, is described and discussed. Finally, the report discusses the use of the MOLCAS package for advanced studies of photo chemical phenomena and the usefulness of the algorithms for constrained geometry optimization in MOLCAS in association with such studies.
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| 7. |
- Gagliardi, L, et al.
(författare)
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Theoretical study of the lowest B-1(U) states of trans-stilbene
- 2002
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Ingår i: The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory. - : American Chemical Society (ACS). - 1520-5215. ; 106:32, s. 7355-7361
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Tidskriftsartikel (refereegranskat)abstract
- The results of a theoretical study of the ground state, 1(1)A(g), and of the lowest B-1(u) states of trans-stilbene are presented. The vertical and adiabatic excitation energies of the lowest B-1(u) states have been computed using multiconfigurational SCF theory, followed by second-order perturbation. theory. It is shown that the two lowest excited states are separated by a small energy gap in the Franck-Condon region. They are the 1(1)B(u), characterized by the HOMO-->LUMO single excitation substantially localized on the ethylenic moiety, and the 2(1)B(u), formed by a combination,of one electron excitations localized mainly on the benzene rings. The most intense transition is found to be the lowest in energy when the interaction between different states is included at the level of second-order perturbation theory. The vibronic structure of emission and absorption spectra of the two lowest B-1(u) states have been determined within the Franck-Condon approximation. The spectrum calculated for the 1(1)B(u) state agrees with the experimental spectrum, while the low intensity band computed for the 2(1)B(u) state has no experimental counterpart. It is concluded that this band is buried in the strong 1(1)B(u) absorption and therefore not observed.
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| 8. |
- Ghigo, Giovanni, et al.
(författare)
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A modified definition of the zeroth-order Hamiltonian in multiconfigurational perturbation theory (CASPT2)
- 2004
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 396:1-3, s. 142-149
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Tidskriftsartikel (refereegranskat)abstract
- A new shifted zeroth-order Hamiltonian is presented, which will be used in second-order multiconfigurational perturbation theory (CASPT2). The new approximation corrects for the systematic error of the original formulation, which led to an relative overestimate of the correlation energy for open shell system, resulting in too small dissociation and excitation energies. Errors in the D, values for 49 diatomic molecules have been reduced with more than 50%. Calculations on excited states of the N-2 and benzene molecules give a similar improvement. (C) 2004 Elsevier B.V. All rights reserved.
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| 9. |
- Guehne, Otfried, et al.
(författare)
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Compatibility and noncontextuality for sequential measurements
- 2010
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Ingår i: PHYSICAL REVIEW A. - 1050-2947. ; 81:2, s. 022121-
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Tidskriftsartikel (refereegranskat)abstract
- A basic assumption behind the inequalities used for testing noncontextual hidden variable models is that the observables measured on the same individual system are perfectly compatible. However, compatibility is not perfect in actual experiments using sequential measurements. We discuss the resulting "compatibility loophole" and present several methods to rule out certain hidden variable models that obey a kind of extended noncontextuality. Finally, we present a detailed analysis of experimental imperfections in a recent trapped-ion experiment and apply our analysis to that case.
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| 10. |
- Gusarov, Sergey, et al.
(författare)
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Correlation potentials for a multiconfigurational-based density functional theory with exact exchange
- 2004
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Ingår i: Theoretical Chemistry accounts. - : Springer Science and Business Media LLC. - 1432-881X .- 1432-2234. ; 112:2, s. 84-94
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Tidskriftsartikel (refereegranskat)abstract
- A density functional theory based on a complete active space self consistent field (CASSCF) reference function with exact exchange is discussed. It is first shown that such a theory may be formulated with a correlation potential dependent on the density function and on the active space used. Auxiliary functions, such as the on-top two-particle density, are used to define uniquely the potential for different active spaces. The paper also analyses the correlation functional for some atomic and molecular cases. Large ab initio calculations are performed to obtain accurate density functions. A correlation potential is then fitted such that the reference CASSCF function gives the same density. The correlation potential values are saved in a data base for future analysis.
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