Spin injection from EuS/Co multilayers into GaAs detected by polarized electroluminescence

We report on the successful spin injection from EuS/Co multilayers into (100) GaAs at low temperatures. The spin injection was verified by means of polarized electroluminescence (EL) emitted from AlGaAs/GaAs-based spin-light-emitting diodes in zero external magnetic field. Spin-polarized electrons were injected from prototype EuS/Co spin injector multilayers. The use of semiconducting and ferromagnetic EuS circumvents the impedance mismatch. The EL was measured in side emission with and without an external magnetic field. A circular polarization of 5% at 8 K and 0 T was observed. In view of the rather rough interface between the GaAs substrate and first EuS layer, improvement of the interface quality is expected to considerably enhance the injected electron spin polarization

A Comparison of Methods for Determining the Molecular Content of Model Galaxies

Recent observations indicate that star formation occurs only in the molecular phase of a galaxy's interstellar medium. A realistic treatment of star formation in simulations and analytic models of galaxies therefore requires that one determine where the transition from the atomic to molecular gas occurs. In this paper we compare two methods for making this determination in cosmological simulations where the internal structures of molecular clouds are unresolved: a complex time-dependent chemistry network coupled to a radiative transfer calculation of the dissociating ultraviolet (UV) radiation field, and a simple time-independent analytic approximation. We show that these two methods produce excellent agreement at all metallicities >~10^-2 of the Milky Way value across a very wide range of UV fields. At lower metallicities the agreement is worse, likely because time-dependent effects become important; however, there are no observational calibrations of molecular gas content at such low metallicities, so it is unclear if either method is accurate. The comparison suggests that, in many but not all applications, the analytic approximation provides a viable and nearly cost-free alternative to full time-dependent chemistry and radiative transfer.Comment: 8 pages, 7 figures, accepted to ApJ, emulateapj format. This version contains typo corrections and changes to figure presentation, but is otherwise the same as the previous versio

Effects of the mean particle size in the deflagration index estimation for cornstarch dust

The National Fire Protection Association (NFPA) defines the dust explosions as a “credible risk”. Hence, to meet the challenge to prevent and protect from the catastrophic effects of these phenomena, it is fundamental to know what are the characteristics and the burning conditions regarding the combustible dusts that could have an effect on the explosion violence. The KSt, also known as deflagration index, is one of the relevant parameters in dust explosions, together with the maximum explosion overpressure generated in the test chamber, the minimumignition energy and so on. In particular, the deflagration index measures the relative explosion severity and it is used in the design of the dust venting protection equipment. However, one of the criticalities of such a parameter is that is strongly affected by the particle mean diameter. Hence, in the following, it will be preliminary presented the validation of a single particle spherical model able to predict the variation of the deflagration index with the increasing mean particle size knowing just one experimental KSt value

Possibility to realize spin-orbit-induced correlated physics in iridium fluorides

Recent theoretical predictions of "unprecedented proximity" of the electronic ground state of iridium fluorides to the SU(2) symmetric $j_{\mathrm{eff}}=1/2$ limit, relevant for superconductivity in iridates, motivated us to investigate their crystal and electronic structure. To this aim, we performed high-resolution x-ray powder diffraction, Ir L$_3$-edge resonant inelastic x-ray scattering, and quantum chemical calculations on Rb$_2$[IrF$_6$] and other iridium fluorides. Our results are consistent with the Mott insulating scenario predicted by Birol and Haule [Phys. Rev. Lett. 114, 096403 (2015)], but we observe a sizable deviation of the $j_{\mathrm{eff}}=1/2$ state from the SU(2) symmetric limit. Interactions beyond the first coordination shell of iridium are negligible, hence the iridium fluorides do not show any magnetic ordering down to at least 20 K. A larger spin-orbit coupling in iridium fluorides compared to oxides is ascribed to a reduction of the degree of covalency, with consequences on the possibility to realize spin-orbit-induced strongly correlated physics in iridium fluorides

Development of an LCA-based tool to assess the environmental sustainability level of cosmetics products

The depletion of natural resources and the downgrading of the environment, driven by globalization and consumerism phenomena, are worldwide pushing the interest in sustainable manufacturing paradigm and environment preservation. It is moreover clear to academia and practitioners that the cosmetics industry needs to update its current operations to face new sustainable requirements and norms due to its ever-growing size and massive consumption of natural resources. Different methodologies, metrics, and indicators have been and are being proposed for solving the complex issues of environmental sustainability evaluation of cosmetics processes and products.MethodsAmong these approaches and methods, product-related assessment tools (e.g., life cycle assessment) are usually more focused on the environmental dimension of sustainability, and they are always based on the life cycle of the product. The core of this paper is on the development of a novel tool to classify cosmetics products based on the results of LCA: the eco-friendliness assessment tool (EFAT). The methodology of the work is structured into 5 main phases: definition of the scientific background of the work, definition of the tool requirements, tool development, testing of the tool, analysis of the results. The eco-friendliness assessment tool proposed is structured into two main parts: (i) process flow 1: environmental impact score and (ii) process flow 2: supplier environmental sustainability assessment.ResultsThe tool has been tested on a cosmetics product manufactured in a cosmetics company located in Italy. The acquisition of raw material process and primary packaging process are the two most critical processes resulting from the impact analysis of LCA methodology. The application of the EFAT tool shows the two possible most sustainable improved scenarios are as follows: (i) exploiting transportation of the primary packaging by sea and (ii) adopting the European location of the primary packaging supplier. The results coming from the tool application allowed the definition of the company product eco-friendliness. The eco-friendliness is symbolized by an alphabetical letter and a color.ConclusionsThe paper proposes a practical tool to assess the environmental sustainability level of cosmetics products, with the intention to overcome two of the main literature gaps found in the state of the art: (i) absence of LCA methodology implementation in the cosmetics industry on makeup products, (ii) absence of tools that rely on the results of the LCA analysis of a cosmetic product for understanding its sustainability level of sustainability

Enhancing the cosmetics industry sustainability through a renewed sustainable supplier selection model

The cosmetics industry requires a long-term sustainable strategy to balance its continuously growing trend worldwide and its resources consumption. In this view, the suppliers' selection process is gaining more attention affecting products' overall sustainability. The objective of this contribution is hence to develop and validate the Cosmetics Sustainable Supplier Selection (C-SSS) model allowing the selection of sustainable suppliers for the cosmetic industry, evaluating them in an objective and balanced manner. The model was built relying on both scientific and grey literature, by incorporating the characteristics of existing SSS models usually used separately. The C-SSS enabled to integrate the EMM approach (to reduce the subjectivity), the ANP approach (to evaluate criteria interconnections), and the TOPSIS and ELECTRE models (to create a hybrid compensation model) to support managers in objectively selecting the most sustainable suppliers. The C-SSS model was applied and validated through an industrial use case in a cosmetics Italian company

An Exploratory Study of Users’ Preference for Different Planting Combinations along Rural Greenways

The literature highlights the importance of vegetation to enhance the ecological and visual qualities of streets and paths; however, when studies specifically focus on rural greenways they do not consider users' assessments of the planting design. This exploratory study aims to contribute to this issue. It is hypothesized that planting combinations characterized by greater variety and aesthetic flow may be more preferred and restorative. To this end, four virtual scenarios simulating bikers moving along a greenway at 25 km/h were created to find out the following: first, what kind of planting combination is the most preferred, and second, which planting combination is perceived as the most restorative by bicycle riders. To assess the experience, subjects were administered a questionnaire made up of: (i) the Perceived Restorativeness Scale-11 with additional items to assess compatibility, familiarity, and preference; (ii) a list of physical and aesthetic attributes; and (iii) information on bicycle use. The results show that participants' preferences were a ffected by the perception of the scenario's restorative value, which was not given exclusively by the degree of naturalness, but by the opportunity the greenway o ffered to engage in social/physical activities. This study shows that preference and restorativeness are not a "simple" matter of quantity of vegetation, but of quality instead, i.e., planting variety. Designers have to consider that the restorative value of greenways is related to the opportunities they offer to engage in physical/social activities

Theoretical predictions for IMF diagnostics in UV spectroscopy of star clusters

We explore the possibility of using UV spectroscopy in combination with broad-band photometry as diagnostic tools for understanding the shape of the initial mass function (IMF) in unresolved stellar populations. Building on our previous work, we extend the Stochastically Lighting Up Galaxies (SLUG) code to include a high-resolution UV spectral synthesizer and equivalent width calculation capabilities. We first gain a qualitative understanding of how UV spectral features behave as the parameters that define a star cluster in SLUG (mass, age, extinction, and IMF slope α3) are changed. We then exploit Bayesian inference techniques to recover the α3 values for clusters simulated with SLUG, using mock observations of these clusters comprised of broad-band photometry and equivalent width measurements of a selection of UV spectral features. We find some improvement when compared to attempts using broad-band photometry alone (with the interquartile range of the α3 posterior PDF shrinking by 32%), although we still do not yet fully break the known degeneracy between the cluster mass and α3. Finally, we make predictions about how effective real observations will be by quantifying our ability to constrain α3 as a function of limiting equivalent width. We find that observations sensitive to a modest equivalent width of 9 ˚ A are sufficient to improve the recovery of the IMF slope parameter by 32% (interquartile range of posterior PDF median residuals), moving to 39% when we include all the significant spectral features in the wavelength range 900 − 3000 ˚ A