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- 2019
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Tidskriftsartikel (refereegranskat)
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- Casolino, M., et al.
(författare)
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Cosmic-ray observations of the heliosphere with the PAMELA experiment
- 2006
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Ingår i: Astrophysics. - : Elsevier BV. ; , s. 1848-1852
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Konferensbidrag (refereegranskat)abstract
- The PAMELA experiment is a multi-purpose apparatus built around a permanent magnet spectrometer, with the main goal of studying in detail the antiparticle component of cosmic rays. The apparatus will be carried in space by means of a Russian satellite, due to launch in 2005, for a three year-long mission. The characteristics of the detectors composing the instrument, alongside the long lifetime of the mission and the orbital characteristics of the satellite, will allow to address several items of cosmic-ray physics. In this paper, we will focus on the solar and heliospheric observation capabilities of PAMELA.
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| 3. |
- Stozhkov, Y. I., et al.
(författare)
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About Separation of Hadron and Electromagnetic Cascades in the Pamela Calorimeter
- 2005
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Ingår i: International Journal of Modern Physics A. - 0217-751X .- 1793-656X. ; 20:29, s. 6745-6748
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Tidskriftsartikel (refereegranskat)abstract
- Results of calibration of the PAMELA instrument at the CERN facilities are discussed. In September, 2003, the calibration of the Neutron Detector together with the Calorimeter was performed with the CERN beams of electrons and protons with energies of 20-180 GeV. The implementation of the Neutron Detector increases a rejection factor of hadrons from electrons about ten times. The results of calibration are in agreement with calculations.
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| 5. |
- Carlson, Rolf, et al.
(författare)
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Identification of important experimental variables in organic synthetic procedures by near-orthogonal experiments
- 2012
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Ingår i: Organic Process Research & Development. - : American Chemical Society (ACS). - 1083-6160 .- 1520-586X. ; 16:8, s. 1371-1377
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Tidskriftsartikel (refereegranskat)abstract
- A new strategy is presented for the design of screening experiments in synthetic chemistry when the objective is to identify the important experimental variables from a limited number of experimental runs. The methodology is based on Taylor expansion (response surface) models The experimental design is constructed in such a way that the vector of the variables in the Taylor model in each run are near-orthogonal to each other. This is achieved by laying out a grid of possible experiments in the experimental space, expanding this candidate experimental design matrix to the corresponding model matrix, i.e. the matrix containing columns for all variables in the Taylor expansion. This model matrix is then factorised by singular value decomposition, SVD. The row in the model matrix that is most parallel to the first singular vectors is selected as the first experiment. .The variation displaced by this first experiment is removed from the elements of the model matrix by projections. The resulting matrix is the orthogonal complement to the first selected row. The procedure is repeated until all dimensions of the model space have been spanned by the selected experiments The singular vectors are mutually orthogonal, and selected experiments will be nearly orthogonal and span the dimensions of the model space. The experiments can be run in sequence and thus allow for a systematic search, one experiment at a time. It is shown that subset selections from such designs in combination with PLS modelling can be used to identify the important variables. The principles are illustrated with two examples: (a) a dibromination of an acetyl with four experimental variables and (b) a synthesis of an enamine by condensing a ketone and morpholine in the presence of molecular sieves in which seven experimental variables are involved. In the acetal bromination, it was found that 5 experiments out of 12 were sufficient for identifying the most important variables. In the enamine example, 8 experiments out of 30 were sufficient.
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- Carlson, Rolf, et al.
(författare)
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Orthogonal experiments in the development of organic synthetic processes
- 2009
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Ingår i: Organic Process Research & Development. - : American Chemical Society (ACS). - 1083-6160 .- 1520-586X. ; 13:4, s. 798-803
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Tidskriftsartikel (refereegranskat)abstract
- A new strategy is presented for the design of explorative experiments in synthetic chemistry when the objective is to identify the important experimental variables. The methodology is based on Taylor expansion (response surface) models, and the principles are: A grid of possible settings of the experimental variables is laid out in the experimental domain. These experiments define a candidate design matrix, DC. From DC, a candidate model matrix, XC is defined by appending columns for each variable in the Taylor model XC is then factored by singular value decomposition (SVD), and XC = USVT. The rows in XC that are most parallel to the singular column vectors in V are selected, and the corresponding experiments in DC are identified. This gives the experimental design. The selected experiments are nearly orthogonal, and they span the dimensions of the model space. The experiments can be run in sequence, and thus, they allow for a systematic search, one experiment at a time. The design principles are illustrated by an example of the dibromination of an acetal. Four variables were studied, and from 12 experiments, all the main effects and all two-factor interaction effects were estimated. From the response surface model, conditions for quantitative yield were predicted, and a mol-scale synthesis carried out under these conditions afforded 98% yield of the isolated pure, >97% product.
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