Can bioleaching of NIB magnets be an answer to the criticality of rare earths? An ex-ante Life Cycle Assessment and Material Flow Cost Accounting

The instability of rare earth elements (REEs) supply chains due to, among others, geopolitical factors brought alternative sources of REEs under the spotlight. Waste from electrical and electronic equipment (WEEE) is considered one of such sources. WEEE recycling is seen as a way not only to mitigate the aforementioned REEs supply risk but also to benefit the environment and society caught currently in a precarious position. Within this context, bioleaching for REEs recovery is gaining attraction, considering that, so far, this process has mainly been used to recover other elements (e.g., Cu, Ni, Zn, Al, Au, Ag). Hitherto, a few lab-scale studies on Nd, Dy, and Pr bioleaching from NIB magnets were identified in the open literature, whereas only one study attempted to perform a simplified LCA analysis of the process. Ergo, this study aims at filling this knowledge gap. For this purpose, the Life Cycle Assessment (LCA) and Material Flow Cost Accounting (MFCA) were performed to assess the process' environmental and economic feasibility after scaling it up from a lab to a pilot scale. Moreover, a break-even analysis was performed to assess the competitiveness of the technology. As the bioleaching of NIB magnets is an emerging concept, this study aimed to identify future process optimisation and development directions. The process was divided into six stages (i.e., demagnetising, shredding, bacteria cultivation, bioleaching, REEs extraction, and oxidation), analysed individually and collectively. Electricity and oxalic acid consumption, together with investment costs, were identified as the main hotspots for future improvement

The S2N2 metallicity calibrator and the abundance gradient of M 33

We introduce the log(Ha/[SII]6717+6731) vs. log(Ha/[NII]6583) (S2N2) diagnostic diagram as metallicity and ionisation parameter indicator for HII regions in external galaxies. The location of HII regions in the S2N2 diagram was studied both empirically and theoretically. We found that, for a wide range of metallicities, the S2N2 diagram gives single valued results in the metallicity-ionisation parameter plane. We demonstrate that the S2N2 diagram is a powerful tool to estimate metallicities of high-redshift (z ~ 2) HII galaxies. Finally, we derive the metallicity for 76 HII regions in M33 from the S2N2 diagram and calculate an O/H abundance gradient for this galaxy of -0.05 (+-0.01) dex kpc^-1.Comment: 10 pages, 3 figures and 2 tables. Accepted for publication in MNRA

Atomic and Molecular Data for Optical Stellar Spectroscopy

High-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics. Examples include studying the chemical structure and evolution of the Milky Way galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. These instruments are located at ground-based 2- to 10-m class telescopes around the world, in addition to the spectrographs with unique capabilities available at the Hubble Space Telescope. The interpretation of these spectra requires high-quality transition data for numerous species, in particular neutral and singly ionized atoms, and di- or triatomic molecules. We rely heavily on the continuous efforts of laboratory astrophysics groups that produce and improve the relevant experimental and theoretical atomic and molecular data. The compilation of the best available data is facilitated by databases and electronic infrastructures such as the NIST Atomic Spectra Database, the VALD database, or the Virtual Atomic and Molecular Data Centre (VAMDC). We illustrate the current status of atomic data for optical stellar spectra with the example of the Gaia-ESO Public Spectroscopic Survey. Data sources for 35 chemical elements were reviewed in an effort to construct a line list for a homogeneous abundance analysis of up to 100000 stars.Comment: Published 30 April 2015 in Physica Script

Biological and molecular structure analyses of the controls on soil organic matter dynamics

Includes bibliographical references (page 170).The dynamics of soil organic carbon (SOC) are controlled by the interaction of biological, physical, and chemical parameters. These are best measured by a combination of techniques such as long-term field sites with a C3↔C4 plant switch. Acid hydrolysis and 14C- dating measure the mean residence time (MRT) of the resistant fraction. Long-term incubation allows the in situ biota to identify and decompose the labile SOC components. Statistical analysis (curve fitting) of the CO2 release curves, determines the pool size and of the two labile fractions (1). The effect of chemical structure is measured with pyrolysismolecular beam mass spectrometry (py-MBMS). The dynamics of charcoal, clay and silt are measured with both 13C and 14C

Indurimento superficiale di leghe di alluminio mediante diffusione di rame

Lo scopo di questo lavoro è quello di sviluppare un processo per incrementare la durezza superficialedelle leghe di alluminio 2024 e 7075 mediante trattamenti di diffusione di rame, depositato elettroliticamentesulla superficie. I trattamenti diffusivi sono stati effettuati in forno in atmosfera inerte a temperaturecomprese nell’intervallo 470-500 °C per un tempo massimo di 24 h, seguiti da trattamenti di solubilizzazionee invecchiamento. I campioni sono stati caratterizzati mediante analisi al microscopio ottico (OM),microscopia elettronica a scansione (SEM), diffrazione a raggi X (XRD) e misure di microdurezza Vickers.La lega 2024, in seguito ai trattamenti di diffusione del rame condotti a temperature prossime ai 495 °C,raggiunge una durezza superficiale di 500 HV0,1, contro 80 HV0,1 del cuore del campione.Ciò è dovuto alla formazione dell’intermetallico Al2Cu. Il trattamento di invecchiamento non influenzalo spessore di diffusione che rimane di circa 50 ?m, bensì modifica la durezza in maniera diversa a secondache l’invecchiamento sia naturale o artificiale. I trattamenti di diffusione condotti sulla lega 7075 atemperature prossime a 500 °C provocano la diffusione del rame fino ad una profondità di 600 ?m e causanouna parziale fusione degli intermetallici superficiali, non permettendo di ottenere un aumento significativodella durezza superficiale. Abbassando la temperatura del trattamento diffusivo (470 °C), la zona interessatadalla diffusione del rame è di circa 100 ?m con una durezza di 860 HV0,1, dovuta alla formazione diintermetallici Al-Cu e Zn-Cu. Anche in questo caso, il successivo invecchiamento artificiale non varia lospessore di diffusione, ma porta ad una diminuzione della durezza superficiale a valori attorno a 500 HV0,1

Disparities in Regional Productivity, Capital Accumulation, and Efficiency across Indonesia: A Convergence Clubs Approach

This paper studies the evolution of regional disparities in labor productivity, capital accumulation, and efficiency across Indonesian provinces over the 1990-2010 period. Through the lens of a non-linear dynamic factor model, we first test the hypothesis that all provinces would eventually converge to a common steady-state path. We reject this hypothesis and find that the provincial dynamics of labor productivity are characterized by two convergence clubs. We next evaluate the dynamics of the proximate determinants of labor productivity and find some mixed results. On the one hand, physical and human capital accumulation are characterized by four and two convergence clubs, respectively. On the other hand, efficiency is characterized by a unique convergence club. The paper concludes suggesting that based on the provincial composition of each club and the common low level of efficiency across Indonesia, considerable improvements in both capital accumulation and efficiency are still needed to reduce regional disparities and accelerate productivity growth

Cool gas and dust in M33: Results from the Herschel M33 extended survey (HERM33ES)

We present an analysis of the first space-based far-IR-submm observations of M 33, which measure the emission from the cool dust and resolve the giant molecular cloud complexes. With roughly half-solar abundances, M33 is a first step towards young low-metallicity galaxies where the submm may be able to provide an alternative to CO mapping to measure their H$_2$ content. In this Letter, we measure the dust emission cross-section $\sigma$ using SPIRE and recent CO and \HI\ observations; a variation in $\sigma$ is present from a near-solar neighborhood cross-section to about half-solar with the maximum being south of the nucleus. Calculating the total H column density from the measured dust temperature and cross-section, and then subtracting the \HI\ column, yields a morphology similar to that observed in CO. The H$_2$/\HI\ mass ratio decreases from about unity to well below 10% and is about 15% averaged over the optical disk. The single most important observation to reduce the potentially large systematic errors is to complete the CO mapping of M 33.Comment: 5 pages, 5 figures Accepted for publication in Astronomy and Astrophysic