30 research outputs found
Thermodynamics of pyrope-majorite, Mg3Al2Si3O12-Mg4Si4O12, solid solution from atomistic model calculations
Static lattice energy calculations, based on empirical pair potentials have been performed for a large set of different structures with compositions between pyrope and majorite, and with different states of order of octahedral cations. The energies have been cluster expanded using pair and quaternary terms. The derived ordering constants have been used to constrain Monte Carlo simulations of temperature-dependent properties in the ranges of 1073 3673K and 0 20 GPa. The free energies of mixing have been calculated using the method of thermodynamic integration. At zero pressure the cubic/tetragonal transition is predicted for pure majorite at 3300 K. The transition temperature decreases with the increase of the pyrope mole fraction. A miscibility gap associated with the transition starts to develop at about 2000K and xmaj 0.8, and widens with the decrease in temperature and the increase in pressure. Activity composition relations in the range of 0 20 GPa and 1073 2673K are described with the help of a high-order Redlich Kister polynomial
Sustainable mining in tropical, biodiverse landscapes: Environmental challenges and opportunities in the archipelagic Philippines
The rising demand for critical metals presents a major economic opportunity for mineral-rich countries. For a sustainable transition to a low-carbon future, it is essential to minimise impacts of mineral resource development to the environment, ecosystems, and societies of these nations. Although there has been considerable progress in the social aspects of the mining sector, environmental metrics are not showing comparable improvement. The Philippines exemplifies this challenge as a country that aims to conserve its exceptional biodiversity to maximise ecosystem services while expanding mining activities for economic growth, in a geographical setting with high mineral potential and vulnerability to natural hazards and climate change. Similar to many mining areas, environmental baselines are mostly non-existent, compounded by a legacy of mining impacts despite an established policy framework. We review issues associated with large- and small-scale mining and identify underlying research challenges and opportunities in the Philippines. Potential environmental research pathways include (i) innovative approaches for catchment scale characterisation and identification of contaminant sources; (ii) quantifying and predicting contaminant transport; (iii) deployment of flexible monitoring devices for larger-scale water quality monitoring programmes; (iv) tailings dam monitoring and management; and (v) resource assessment and metal recovery in ores and tailings. By integrating geomorphological tools with geochemical data, as well as 2D/3D numerical modelling techniques, it becomes possible to predict and understand the behaviour and fate of contaminants across different spatial and temporal scales. The development of cost-effective water quality assessment devices and protocols can help overcome logistical challenges in monitoring a wider range of hydrological conditions. Advanced applications of remote sensing, combined with machine learning, and geophysical monitoring systems provide new opportunities to detect mining footprints and observe change in tailings dams more effectively. Potential impacts of mine wastes can be further minimised by exploring innovative technologies such as the use of metal-accumulating native plant species and environmentally safe solvents to reprocess modern and legacy tailings. Insights from these pathways will enable the realisation of a more sustainable mining future, through the incorporation of findings into existing and future governmental and small- and large-scale mining policy and practice. This will lead to sustainable development for society, particularly in nations that are well positioned to benefit from sustainable mineral resource development
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Optimization strategies in credit portfolio management
This paper focuses on the application of an original global optimization algorithm, based on the hybridization between a genetic algorithm and a semi-deterministic algorithm, for the resolution of various constrained optimization problems for realistic credit portfolios. Results are analyzed from a financial point of view in order to confirm their relevance