Cross sections for the excitation of isovector charge-exchange resonances in 208Tl

The Glauber approximation for the treatment of heavy-ion scattering, has already been shown to give reliable predictions for the reaction cross section in the particular case of intermediate energy charge-exchange processes. In the present work, we couple a Glauber-type model to microscopic Random Phase Approximation calculations of the charge-exchange excitations of $^{208}$Pb. The aim is to solve the longstanding question whether the very elusive charge-exchange isovector monopole has been really identified in the past experiments, or other multipoles were prevalent in the observed spectra.Comment: text + 4 figures; accepted for publication in Phys. Rev.

Climate Information for Improved Planning and Management of Mega Cities (Needs Perspective)

The majority of the population of the planet (6.6 billion) now live in urban areas, which have distinct impacts upon climate at scales from the local to the global. This urban effect is due to the physical form of the city (its three-dimensional geometry and material composition) and its functions (the day-to-day activity patterns that generate emissions of waste heat and materials into the overlying air). While a substantial body of knowledge on the science of urban climates has been developed over the past fifty years, there is little evidence that this knowledge is incorporated into urban planning and design practice. This paper focuses on this gap by examining the nature of urban climate expertise and the needs of those that make decisions about urban areas. In conclusion it makes recommendations to maintain and enhance urban observations and data; to improve understanding of local, regional and global climate linkages; to develop tools for practical planning; and to disseminate urban climate knowledge and its relevance to urban planning to both practicing meteorologists and urban decision makers

Splitting of the Dipole and Spin-Dipole Resonances

Cross sections for the 90,92,94Zr(p,n) reactions were measured at energies of 79.2 and 119.4 MeV. A phenomenological model was developed to describe the variation with bombarding energy of the position of the L=1 peak observed in these and other (p,n) reactions. The model yields the splitting between the giant dipole and giant spin dipole resonances. Values of these splittings are obtained for isotopes of Zr and Sn and for 208Pb.Comment: 14 pages, 4 figure

Complete Set of Polarization Transfer Observables for the 12C(p,n)^{12}{\rm C}(p,n) Reaction at 296 MeV and 0∘^{\circ}

A complete set of polarization transfer observables has been measured for the $^{12}{\rm C}(p,n)$ reaction at $T_p=296 {\rm MeV}$ and $\theta_{\rm lab}=0^{\circ}$. The total spin transfer $\Sigma(0^{\circ})$ and the observable $f_1$ deduced from the measured polarization transfer observables indicate that the spin--dipole resonance at $E_x \simeq 7 {\rm MeV}$ has greater $2^-$ strength than $1^-$ strength, which is consistent with recent experimental and theoretical studies. The results also indicate a predominance of the spin-flip and unnatural-parity transition strength in the continuum. The exchange tensor interaction at a large momentum transfer of $Q \simeq 3.6 {\rm fm}^{-1}$ is discussed.Comment: 4 pages, 4 figure

Schwarz type preconditioners for the neutron diffusion equation

[EN] Domain decomposition is a mature methodology that has been used to accelerate the convergence of partial differential equations. Even if it was devised as a solver by itself, it is usually employed together with Krylov iterative methods improving its rate of convergence, and providing scalability with respect to the size of the problem. In this work, a high order finite element discretization of the neutron diffusion equation is considered. In this problem the preconditioning of large and sparse linear systems arising from a source driven formulation becomes necessary due to the complexity of the problem. On the other hand, preconditioners based on an incomplete factorization are very expensive from the point of view of memory requirements. The acceleration of the neutron diffusion equation is thus studied here by using alternative preconditioners based on domain decomposition techniques inside Schur complement methodology. The study considers substructuring preconditioners, which do not involve overlapping, and additive Schwarz preconditioners, where some overlapping between the subdomains is taken into account. The performance of the different approaches is studied numerically using two-dimensional and three-dimensional problems. It is shown that some of the proposed methodologies outperform incomplete LU factorization for preconditioning as long as the linear system to be solved is large enough, as it occurs for three-dimensional problems. They also outperform classical diagonal Jacobi preconditioners, as long as the number of systems to be solved is large enough in such a way that the overhead of building the pre-conditioner is less than the improvement in the convergence rate. (C) 2016 Elsevier B.V. All rights reserved.The work has been partially supported by the spanish Ministerio de Economía y Competitividad under projects ENE 2014-59442-P and MTM2014-58159-P, the Generalitat Valenciana under the project PROMETEO II/2014/008 and the Universitat Politècnica de València under the project FPI-2013. The work has also been supported partially by the Swedish Research Council (VR-Vetenskapsrådet) within a framework grant called DREAM4SAFER, research contract C0467701.Vidal-Ferràndiz, A.; González Pintor, S.; Ginestar Peiro, D.; Verdú Martín, GJ.; Demazière, C. (2017). Schwarz type preconditioners for the neutron diffusion equation. Journal of Computational and Applied Mathematics. 309:563-574. https://doi.org/10.1016/j.cam.2016.02.056S56357430

Bioclimatic Architecture and Urban Morphology. Studies on Intermediate Urban Open Spaces

This paper deals with the interactions between biophysical and microclimatic factors on the one hand with, on the other, the urban morphology of intermediate urban open spaces, the relationship between environmental and bioclimatic thermal comfort, and the implementation of innovative materials and the use of greenery, aimed at the users’ well-being. In particular, the thermal comfort of the open spaces of the consolidated fabrics of the city of Rome is studied, by carrying out simulations of cooling strategies relating to two scenarios applied to Piazza Bainsizza. The first scenario involves the use of cool materials for roofs, cladding surfaces, and pavement, while the second scenario, in addition to the cool materials employed in the first scenario, also includes the use of greenery and permeable green surfaces. The research was performed using summer and winter microclimatic simulations of the CFD (ENVI-met v. 3.1) type, in order to determine the dierent influences of the materials with cold colors, trees, and vegetated surfaces on the thermal comfort of the urban morphology itself. Meanwhile, the comfort assessment was determined through the physiological equivalent temperature (PET) calculated with the RayMan program. The first scenario, with the use of cool materials, improves summer conditions and reduces the urban heat island eect but does not eliminate thermal discomfort due to the lack of shaded surfaces and vegetation. The second scenario, where material renovations is matched with vegetation improvements, has a slightly bad eect on winter conditions but drastically ameliorates the summer situation, both for direct users and, thanks to the strong reduction of the urban heat island eect, to urban inhabitants as a whole

Influence of ground surface characteristics on the mean radiant temperature in urban areas

The effect of variations in land cover on mean radiant surface temperature (Tmrt) is explored through a simple scheme developed within the radiation model SOLWEIG. Outgoing longwave radiation is parameterised using surface temperature observations on a grass and an asphalt surface, whereas outgoing shortwave radiation is modelled through variations in albedo for the different surfaces. The influence of surface materials on Tmrt is small compared to the effects of shadowing. Nevertheless, altering ground surface materials could contribute to a reduction on Tmrt to reduce the radiant load during heat-wave episodes in locations where shadowing is not an option. Evaluation of the new scheme suggests that despite its simplicity it can simulate the outgoing fluxes well, especially during sunny conditions. However, it underestimates at night and in shadowed locations. One grass surface used to develop the parameterisation, with very different characteristics compared to an evaluation grass site, caused Tmrt to be underestimated. The implications of using high resolution (e.g. 15 minutes) temporal forcing data under partly cloudy conditions are demonstrated even for fairly proximal sites

Estudo de conforto em espaços abertos em região de clima temperado: o caso de Glasgow, Reino Unido

O estudo da sensação de conforto térmico em espaços abertos deve ser entendido como primordial para o planejamento climaticamente adequado de áreas urbanas. Através do aumento da atratividade das àreas abertas e do incentivo às atividades ao ar livre, o planejamento urbano norteado do pelas preferências térmicas da população torna-se um agente facilitador do uso desses espaços. O presente trabalho analisa a sensação térmica de moradores de Glasgow, Reino Unido, localizada em região temperada, comparando respostas obtidas por meio de entrevistas estruturadas a índices utilizados pela meteorologia (Wind Chill e THSW) e em estudos de conforto (PET e PMV). Os dados foram coletados em 19 campanhas de monitoramento, no período do inverno ao verão de 2011. Para a coleta de dados, foi utilizada uma estação Davis Vantage Pro2, contendo sensores de temperatura e umidade relativa, anemômetro e piranômetro. Foi confeccionado um termômetro de globo, utilizado para obtenção da temperatura radiante média (TRM), equipado com um data logger (Tinytag-TGP-4500). Os resultados indicam que os índices THSW e PET foram os que mais se aproximaram da resposta térmica dos entrevistados, podendo ser aplicados no entendimento das condições do clima na cidade e entorno de Glasgow

U.K. climate projections: Summer daytime and nighttime urban heat island changes in England’s major cities

In the United Kingdom, where 90% of residents are projected to live in urban areas by 2050, projecting changes in urban heat islands (UHIs) is essential to municipal adaptation. Increased summer temperatures are linked to increased mortality. Using the new regional U.K. Climate Projections, UKCP18-regional, we estimate the 1981–2079 trends in summer urban and rural near-surface air temperatures and in UHI intensities during day and at night in the 10 most populous built-up areas in England. Summer temperatures increase by 0.45°–0.81°C per decade under RCP8.5, depending on the time of day and location. Nighttime temperatures increase more in urban than rural areas, enhancing the nighttime UHI by 0.01°–0.05°C per decade in all cities. When these upward UHI signals emerge from 2008–18 variability, positive summer nighttime UHI intensities of up to 1.8°C are projected in most cities. However, we can prevent most of these upward nighttime UHI signals from emerging by stabilizing climate to the Paris Agreement target of 2°C above preindustrial levels. In contrast, daytime UHI intensities decrease in nine cities, at rates between −0.004° and −0.05°C per decade, indicating a trend toward a reduced daytime UHI effect. These changes reflect different feedbacks over urban and rural areas and are specific to UKCP18-regional. Future research is important to better understand the drivers of these UHI intensity changes