| 1. |
- Ade, Peter, et al.
(författare)
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The Simons Observatory : science goals and forecasts
- 2019
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :2
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Tidskriftsartikel (refereegranskat)abstract
- The Simons Observatory (SO) is a new cosmic microwave background experiment being built on Cerro Toco in Chile, due to begin observations in the early 2020s. We describe the scientific goals of the experiment, motivate the design, and forecast its performance. SO will measure the temperature and polarization anisotropy of the cosmic microwave background in six frequency bands centered at: 27, 39, 93, 145, 225 and 280 GHz. The initial con figuration of SO will have three small-aperture 0.5-m telescopes and one large-aperture 6-m telescope, with a total of 60,000 cryogenic bolometers. Our key science goals are to characterize the primordial perturbations, measure the number of relativistic species and the mass of neutrinos, test for deviations from a cosmological constant, improve our understanding of galaxy evolution, and constrain the duration of reionization. The small aperture telescopes will target the largest angular scales observable from Chile, mapping approximate to 10% of the sky to a white noise level of 2 mu K-arcmin in combined 93 and 145 GHz bands, to measure the primordial tensor-to-scalar ratio, r, at a target level of sigma(r) = 0.003. The large aperture telescope will map approximate to 40% of the sky at arcminute angular resolution to an expected white noise level of 6 mu K-arcmin in combined 93 and 145 GHz bands, overlapping with the majority of the Large Synoptic Survey Telescope sky region and partially with the Dark Energy Spectroscopic Instrument. With up to an order of magnitude lower polarization noise than maps from the Planck satellite, the high-resolution sky maps will constrain cosmological parameters derived from the damping tail, gravitational lensing of the microwave background, the primordial bispectrum, and the thermal and kinematic Sunyaev-Zel'dovich effects, and will aid in delensing the large-angle polarization signal to measure the tensor-to-scalar ratio. The survey will also provide a legacy catalog of 16,000 galaxy clusters and more than 20,000 extragalactic sources.
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| 2. |
- Zago, G. P., et al.
(författare)
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Product characteristics in simultaneous crystallization of NaCl and CaSO4 from aqueous solution under different evaporation rates
- 2019
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Ingår i: Desalination. - : ELSEVIER SCIENCE BV. - 0011-9164 .- 1873-4464. ; 457, s. 85-95
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about simultaneous crystallization in evaporative processes for water reuse is important for the promotion of particles with desirable characteristics. In this work, simultaneous crystallization of sodium chloride and calcium sulfate hemihydrate (HH) from aqueous solutions in unseeded batch mode is addressed. Both the crystallization mechanisms and the resulting particle morphological features have been identified. NaCl particles are generated by heterogeneous primary nucleation in solution, followed by growth and NaCl agglomeration. Calcium sulfate hemihydrate (HH) particles are also formed by heterogeneous primary nucleation in solution followed by crystal growth. HH crystals agglomerate with NaCl in all particle size ranges. Product particles are thus agglomerates with multimodal population densities in submillimetric size ranges, with HH widely dispersed throughout the size span of the particulate product. In comparison with NaCl binary solutions, simultaneous crystallization promotes the formation of larger, less polydisperse NaCl particles, Low super saturations (low evaporation rates) inhibit HH agglomeration with NaCl. The submillimetric sized particles formed during simultaneous crystallization of NaCl and HI-I indicate ease in solid-liquid downstream separation.
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| 3. |
- Penha, Frederico Marques, et al.
(författare)
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Simultaneous Crystallization of NaCl and KCl from Aqueous Solution : Elementary Phenomena and Product Characterization
- 2018
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Ingår i: Crystal Growth & Design. - : AMER CHEMICAL SOC. - 1528-7483 .- 1528-7505. ; 18:3, s. 1645-1656
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Tidskriftsartikel (refereegranskat)abstract
- The main elementary processes were identified during simultaneous crystallization of NaCl and KCl from aqueous solutions by the batchwise evaporative method using NaCl seeds. In the early stages of the batch operation, when only NaCl crystallizes, the main elementary processes are molecular crystal growth, agglomeration, and secondary nucleation. When the eutonic condition is exceeded, a KCl primary nucleation event takes place in solution. Subsequently, part of the resulting KCl particles agglomerate with the NaCl particles. Besides, epitaxial growth of KCI upon NaCl crystals takes place. Consequently, the product is comprised of mixed composition polycrystalline particles and single crystals of each salt. The elementary phenomena just described were sensitive to crystallization conditions such as evaporation rate, seed size, and seed content, suggesting the possibility of controlling the morphological features of the particulate product as well as the chemical composition of its size fractions. Such knowledge is important in the context of wastewater treatment, where the particulate product should be suitable either for disposal as a residue or for further processing in easily separable size fractions for exploitation of valuable components.
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| 4. |
- Penha, Frederico Marques, et al.
(författare)
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Strategies To Control Product Characteristics in Simultaneous Crystallization of NaCl and KCl from Aqueous Solution : Seeding with KCl
- 2019
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Ingår i: Crystal Growth & Design. - : AMER CHEMICAL SOC. - 1528-7483 .- 1528-7505. ; 19:2, s. 1257-1267
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Tidskriftsartikel (refereegranskat)abstract
- To meet contemporary industry needs, saline wastewater treatment with zero liquid discharge goals is gaining increasing attention. In this context, evaporative crystallization has been applied to simultaneously remove all dissolved compounds as a solid residue. By conducting simultaneous crystallization in a way that the components crystallize as single particles, their downstream separation as products is made simple, so that no solid waste is generated. We have recently identified the main phenomena that control particle morphology for batchwise simultaneous crystallization in the NaCl-KCl-H2O model system seeded with NaCl. In this work, a process strategy is proposed, wherein crystallization elementary phenomena are tuned by seeding with KCl particles. Formation of multicomponent particles was inhibited with a small seed surface area, because the epitaxial growth of NaCl upon the KCl seeds was hampered. By a proper choice of seeding policy, the product may be classified into large particles rich in KCl (purity higher than 90 wt %) and smaller particles rich in NaCl (similar to 75 wt %). Secondary nucleation and epitaxial growth of NaCl on KCl were the main hindrances to the formation of pure populations of each compound.
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