Search results for " magnesium"
showing 10 items of 60 documents
Nuclear Charge Radii ofMg21−32
2012
Charge radii of all magnesium isotopes in the sd shell have been measured, revealing evolution of the nuclear shape throughout two prominent regions of assumed deformation centered on (24)Mg and (32)Mg. A striking correspondence is found between the nuclear charge radius and the neutron shell structure. The importance of cluster configurations towards N=8 and collectivity near N=20 is discussed in the framework of the fermionic molecular dynamics model. These essential results have been made possible by the first application of laser-induced nuclear orientation for isotope shift measurements.
Emergent Soft Monopole Modes in Weakly-Bound Deformed Nuclei
2014
Based on the Hartree-Fock-Bogoliubov solutions in large deformed coordinate spaces, the finite amplitude method for quasiparticle random phase approximation (FAM-QRPA) has been implemented, providing a suitable approach to probe collective excitations of weakly-bound nuclei embedded in the continuum. The monopole excitation modes in Magnesium isotopes up to the neutron drip line have been studied with the FAM-QRPA framework on both the coordinate-space and harmonic oscillator basis methods. Enhanced soft monopole strengths and collectivity as a result of weak-binding effects have been unambiguously demonstrated.
Nuclear ground-state spins and magnetic moments ofMg27,Mg29, andMg31
2008
The ground-state spins and magnetic moments of neutron-rich {sup 27}Mg, {sup 29}Mg, and {sup 31}Mg were measured for the first time with laser and {beta}-NMR spectroscopy at ISOLDE/CERN. The hyperfine structure of {sup 27}Mg--observed in fluorescence--confirms previous assignments of the spin I=1/2 and reveals the magnetic moment {mu}{sub I}({sup 27}Mg)=-0.4107(15){mu}{sub N}. The hyperfine structure and nuclear magnetic resonance of optically polarized {sup 29}Mg--observed in the asymmetry of its {beta} decay after implantation in a cubic crystal--give I=3/2 and {mu}{sub I}({sup 29}Mg)=+0.9780(6){mu}{sub N}. For {sup 31}Mg they yield together I=1/2 and {mu}{sub I}({sup 31}Mg)=-0.88355(15){…
Collectivity of neutron-rich magnesium isotopes investigated by projected shell model calculations
2013
The abnormally large collectivity of neutron-rich magnesium isotopes in the “island of inversion” has not been well understood. It has been commented that the unexpectedly large deformations observed in the magnesium isotopes are attributed to the neutron f7/2 intruder orbits involved remarkably even in the ground states, which points to nuclear force directly. Recently, a new isospin-dependent Nilsson potential was suggested to improve the calculations of the ground states of magnesium isotopes. With the improved Nilsson potential, in the present work we investigate the collectivity of excited states by using the projected shell model. To avoid the collapse of the BCS pairing, which occurs…
Integrated production of fresh water, sea salt and magnesium from sea water
2012
Seawater desalination is becoming an important source of fresh water in several countries all around the world. One of the main drawbacks of desalination processes, however, is related to the disposal of large quantities of concentrated brine, which is an always-present by-product of the process. An integrated production of fresh water and salts may be achieved using the discharge brine from a desalination plant as a feed for conventional salt ponds, with the advantages of using brine more concentrated than sea water and, in the case of thermal desalination plants, warmer than sea water. By doing so, the process is faster as a consequence of the enhancement of evaporation rate on the surfac…
Influence of Operational Strategies for the Recovery of Magnesium Hydroxide from Brines at a Pilot Scale
2022
The continuous depletion of minerals caused by land mining and the increase in their demand have pushed the development of novel sustainable technological processes for mineral recovery from unconventional sources. In this context, magnesium (Mg) has gained considerable attention for its peculiar properties and high relevance of its compounds, such as magnesium hydroxide, Mg(OH)2. In the present work, the influence of several operating conditions on the Mg(OH)2 precipitation process was thoroughly investigated by adopting a novel multiple feed-plug flow reactor. The influence of (i) initial Mg2+ concentrations in the feed stream; (ii) brine and alkaline flow rates; and (iii) the product rec…
Techno-economic analysis of a novel hybrid system for the valorisation of SWRO brines in a minor Sicilian island
2021
In small remote islands, freshwater scarcity is an issue to which several viable solutions have already been found employing constantly evolving desalination technologies. The several RO plants in the Canary and minor Sicilian Islands are just an example . However, the beneficial application of seawater desalination is accompanied by a problematic matter: the production of high salinity brines. Not only do they compromise the aquatic ecosystem but their treatment in order to respect environmental regulations is costly too. Worth noting how these so-called “wastewater streams” present a high concentration of valuable raw materials, such as magnesium and calcium or sodium chloride, that are e…
Development of a pilot plant for the recovery of magnesium hydroxide from waste brines
Waste brines from various industrial processes, mainly from saltworks, are an important source of minerals, such as magnesium, table salt and potable water.
Reactive crystallisation process for magnesium recovery from concentrated brines
2014
Seawater brines, generated either by natural or anthropic processes, often cause significant environmental issues related to their disposal. A clear example is the case of brines from desalination plants, which can have severe environmental impacts on the receiving water body. On the other side, brines can represent a rich and appealing source of raw materials, especially when they are very concentrated, as it happens with bitterns (i.e. exhausted brines) produced in saltworks. In particular, magnesium concentration can reach values up to 30-40 kg/m3 of brine, which is 20-30 times that of typical seawater. An experimental campaign has been carried out in the present work for assessing the p…