Search

This study investigated the effect of mechanical stirring time on liquid gallium (Ga)-oxide amalgams using linear and nonlinear viscoelastic properties in dynamic oscillatory shear. The liquid Ga-oxide amalgams with different stirring times were prepared by exposing liquid Ga to the atmosphere under continuous stirring. Linear viscoelasticity of all amalgams exhibited an elastic-dominant behavior. When plotted versus stirring time, elastic modulus increased gradually, which was described successfully by a power-law-type equation for a percolation behavior. The nonlinear viscoelasticity of the amalgams was analyzed using the conventional strain-sweep data and the sequence of physical processes (SPP) method. The critical strain amplitudes determined from the strain-sweep data showed that the yielding of the amalgams occurred earlier and more gradually with increasing stirring time. The SPP analysis using transient Cole–Cole plots revealed that all amalgams experienced intracycle nonlinear behavior consisting of three physical processes (recovery, elastic softening, and yielding) within an oscillation cycle. Intriguingly, the structure recovery rate evaluated by the maximum intracycle elasticity exhibited a nonmonotonic behavior, where the maximum recovery rate was achieved at the stirring time of 5 min. Finally, taking both linear and nonlinear properties, we suggested a material–property co-plot for the printability evaluation of liquid Ga-oxide amalgams. [ABSTRACT FROM AUTHOR]

It remains a big challenge to synthesize two-dimensional (2D) GaN material for applications in power nanodevices. Traditional synthetic methods require complex equipment and processes and time consuming. Here, we reported a two-step route to prepare polycrystalline 2D GaN film. The amorphous ultrathin Ga2O3 film was first exfoliated from the surface of liquid gallium. In a vapor phase reaction, 2D Ga2O3 film was then converted into 2D GaN film while maintaining the 2D morphology. Raman and high-resolution transmission electron microscope (HRTEM) analysis implies the successful synthesis of wurtzite-type GaN ultrathin film. This simple strategy proposed in this work will provide more opportunities for applications of GaN ultrathin film in many devices. [ABSTRACT FROM AUTHOR]

Ga2O3 is a promising material in the optoelectronics and semiconductor industry. In this work, gallium oxide thin films were deposited via radio frequency (RF) sputtering, using a liquid Ga target. The reactive sputtering was carried out using different oxygen flow rates and DC target potentials induced via the RF power. The thickness of the samples varied between 160 nm and 460 nm, depending on the preparation conditions. The composition and the refractive index of the layers were investigated via energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry, respectively. It was found that, through the use of a lower DC target potential, a better film quality and higher oxygen content can be achieved. The reactive sputtering was modeled based on the Berg model, with the aim of determining the sputtering yields and the sticking coefficient. It was shown that an increase in DC target potential leads to the preferential sputtering of gallium. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) generation via metal hydrolysis is a promising eco-friendly technique that has been widely accepted by the industrial sector. This work mainly focuses on stable H 2 production through a simple surface-etching process by hydrofluoric acid (HF) to expel the passive aluminum oxide (Al 2 O 3) layer. The HF-treated aluminum (Al) metal is allowed to react with liquid gallium (Ga) adopting Al–Ga hydrolysis in three different electrolytic solutions of hydrochloric acid (HCl), sodium hydroxide (NaOH), and neutral sodium chloride (NaCl) solutions (named Ga-Al-water reaction). Significantly, the high H 2 productivity of 95.9% achieved in 0.4 M NaCl solution at various temperatures (35–65 °C), further maintained the long-term stability of 92.3% for about 25 h at 35 °C. Density functional theory (DFT) calculations confirm the spontaneity of the initial Al oxidation by the Ga liquid metal, leading to spontaneous water-splitting reactions. Furthermore, the Ga catalyst was recovered even after five reusability cycles without productivity decay. This method yields aluminum hydroxide (Al(OH) 3) as reaction byproducts which could enable resource circulation in pharmaceutical, textile dyeing, and various chemical industries. This study demonstrates the feasibility of the new Ga-Al-water system with an enhanced Ga–Al contact for large-scale H 2 production from seawater and portable fuel cell devices. [Display omitted] • Ga–Al oxidation facilitated production of H 2. • Ga–Al reaction in neutral solution reduced the risk of thermal explosion. • DFT calculations explore the spontaneity of Al oxidation. • Recycling of Aluminum hydroxide has merits to reduce the cost. • Hydrogen production from Ga-Al-water reaction is economically affordable. [ABSTRACT FROM AUTHOR]

In order to design a more compact small nuclear reactor, liquid metal gallium can be selected as the reactor coolant. Gallium is rarely used in reactor as liquid metal coolant, however, due to its excellent thermal conductivity and low melting point, research on the flow and heat transfer characteristics of liquid metal gallium in channels can provide a theory basis for nuclear reactor design optimization and relax reactor safety limits. The flow heat transfer characteristics of liquid gallium are obtained by calculating the surface heat transfer coefficient of liquid gallium in various thermal and structural parameters. The calculation results show that the heat transfer between liquid gallium and the pipe wall can be enhanced by the increase of the inlet flow velocity, the increase of the wall heat flux density, or the reduction of the pipe size. When the hydraulic diameter of each pipe is the same, the heat exchange effect of liquid gallium flow in tubes is: triangle tube>square tube>round tube. The flow heat exchange effect of liquid gallium is better than that of lead-bismuth fluid.

Silver (Ag) nanoalloys play significant roles in several industrial applications. While still many sustainable frameworks can be explored for the synthesis and functional incorporations, the control of phase and structure at the nanoscale still is a major challenge for their practical implementation. In this study, liquid-phase gallium (Ga(L)) nano-/microspheres were utilized for this purpose, investigating their function as reaction media and metallic alloying elements for the development of one-dimensional (1D) Ag–Ga nanoalloys from a silver fluoride precursor. Ultrasonic input at near room temperature was selected for the green synthesis method. The mechanisms for the nucleation, anisotropic growth, and morphological development under ultrasonic oscillations were comprehensively analyzed. The experimental outcomes revealed that the development of 1D Ag–Ga nanoalloys was in correlation with the ultrasonic exposure time, influencing the inter-/intraparticle interactions, modulating the Ga(L) nano-/microsphere dimensional and structural properties, and establishing Ag–Ga bimetallic core–shell microsystems accordingly. The subsequent self-assembly mechanisms were observed to have been primarily driven by Ga(L) surface tension and intermolecular forces promoting spontaneous Ag–Ga liquid–solid interfacial wetting and intermetallic diffusion. The nucleation and crystallization of the 1D nanoalloys developed following two possible pathways for the differentiation of morphologies in the form of either nanoneedles or nanorods identified as the Ag2Ga crystal phase. We observed that the key advantage of Ga(L) nano-/microspheres as the reaction media is the direct control of the phase and morphological development of the 1D Ag–Ga batch structures, demonstrating a straightforward route for the green synthesis of engineered nanoalloys for catalytic applications. [ABSTRACT FROM AUTHOR]

Fine-grained 7034 aluminium alloys were soldered with Zn–5Al filler metals, using liquid Ga as protective coatings to remove oxide films of the base and filler metals and prevent secondary oxidation. Holding times and coating modes were adjusted by experiments. Applying the Ga coating on both the base and filler metals caused the Ga enrichment in the α-Al particles and the formation of Mg2Ga5 intermetallic compound at the bonding interface, deteriorating joint mechanical performance. Ga enrichment was prevented by applying the coating on the filler metal alone, which avoided the early contact of Ga with Al substrate and reduced the mass of Ga in the joint. The tensile strength increased significantly to 159∼185 MPa with a sufficient holding time. [ABSTRACT FROM AUTHOR]

Gallium nanoparticles (Ga NPs) are attracting increasing attention because of their appealing physical‐chemical properties. In particular, their mechanical properties play a key role in the implementation of these core‐shell structures on certain applications, such as soft and stretchable electronics. Thus, efforts are being addressed to modulate them mainly by chemical means. In contrast, this study investigates how the mechanical properties of the outer gallium thin oxide shell change when its thickness is increased through a thermal oxidation strategy. Specifically, as‐deposited Ga NPs, as well as those subjected to thermal oxidation at 300 °C for three different times, are studied by performing single‐particle indentations by atomic force microscopy over a wide range of NP radius. This analysis helps to confirm that the Reissner's thin‐shell model for small deformations within the elastic regime is obeyed. From these data, the dependence of the shell stiffness and the Young's modulus of the gallium oxide on the thermal treatment is obtained. It is found that the shell stiffness increases with the annealing time, even by a factor of 50 under prolonged thermal oxidation, while the gallium oxide Young's modulus, close to 30 GPa, does not change significantly. [ABSTRACT FROM AUTHOR]

Gallium (Ga) is highly valuable as an "active" plasmon in nanooptics due to its low melting point. We numerically investigate the surface plasmon difference between liquid and solid states for spherical and cylindrical Ga nanostructures. In the deep UV–visible region, it is found that the liquid Ga nanostructures can exhibit more pronounced plasmon than the solid, and very high liquid-solid optical contrast is achieved in cylindrical Ga nanostructures. However, for spherical Ga particles in vacuum, the liquid-solid optical contrast is very low, and only extremely small Ga spheres have high liquid-solid optical contrast. In order to achieve high liquid-solid optical contrast, an appropriately large aspect ratio or small size of Ga nanostructures is required.The research will promote the fundamental understanding of the surface plasmon of liquid and solid Ga, and be important for optical sensing, phase-change optical storage and high-contrast optical switches. • Gallium (Ga) is highly valuable as an "active" plasmon in nanooptics due to its low melting point. The liquid Ga nanostructures can exhibit more pronounced plasmon than the solid. • Very high liquid-solid optical contrast is achieved in cylindrical Ga nanostructures. • However, for spherical Ga particles in vacuum, the liquid-solid optical contrast is very low, and only extremely small Ga spheres have high liquid-solid optical contrast. • In order to achieve high liquid-solid optical contrast, an appropriately large aspect ratio or small size of Ga nanostructures is required. [ABSTRACT FROM AUTHOR]

Carbon materials have great potential for applications in energy, biology, and environment due to their excellent chemical and physical properties. Their preparation by carbonization methods encounters limitations and the carbon loss during pyrolysis in the form of gaseous molecules results in low yield of carbon materials. Herein a low-energy (600 °C) and high-yield (82 wt.%) carbonization strategy is developed using liquid gallium-assisted pyrolysis of metal-organic frameworks (MOFs) affording the N-doped carbon nanotube (CNT) non-hollow frameworks encapsulating Co nanoparticles. The liquid gallium layer offers protection against air, promotes heat transfer, and limits the escape of small carbonaceous gaseous molecules, which greatly improve the yields of the pyrolysis reaction. Experimental and theoretical results reveal that the synergistic interaction between CNTs and N/O-containing groups gives a non-hollow framework composed of N/O-enriched and open CNTs (NOCNTF-15, 15 denotes the 15 mm thickness of the liquid gallium layer during the pyrolysis) with high specific capacity (185 mAh g -1 at 10 A g -1 ) and ultra-stable cyclability (stable operation at 10 A g -1 and 50 °C for 20 000 cycles). This study provides a unique approach to carbonization that facilitates the practical application of low-cost CNTs and other MOFs-derived carbon materials in high-performance sodium-ion batteries (SIBs)., (© 2024 Wiley‐VCH GmbH.)

The atomic mobility in liquid pure gallium and a gallium-nickel alloy with 2 at% of nickel is studied experimentally by incoherent quasielastic neutron scattering. The integral diffusion coefficients for all-atom diffusion are derived from the experimental data at different temperatures. DFT-based ab-initio molecular dynamics (MD) is used to find numerically the diffusion coefficient of liquid gallium at different temperatures, and numerical theory results well agree with the experimental findings at temperatures below 500 K. Machine learning force fields derived from ab-initio molecular dynamics (AIMD) overestimate within a small 6% error the diffusion coefficient of pure gallium within the genuine AIMD. However, they better agree with experiment for pure gallium and enable the numerical finding of the diffusion coefficient of nickel in the considered melted alloy along with the diffusion coefficient of gallium and integral diffusion coefficient, that agrees with the corresponding experimental values within the error bars. The temperature dependence of the gallium diffusion coefficientDGa(T)follows the Arrhenius law experimentally for all studied temperatures and below 500 K also in the numerical simulations. However,DGa(T)can be well described alternatively by an Einstein-Stokes dependence with the metallic liquid viscosity following the Arrhenius law, especially for the MD simulation results at all studied temperatures. Moreover, a novel variant of the excess entropy scaling theory rationalized our findings for gallium diffusion. Obtained values of the Arrhenius activation energies are profoundly different in the competing theoretical descriptions, which is explained by different temperature-dependent prefactors in the corresponding theories. The diffusion coefficient of gallium is significantly reduced (at the same temperature) in a melted alloy with natural nickel, even at a tiny 2 at% concentration of nickel, as compared with its pure gallium value. This highly surprising behavior contradicts the existing excess entropy scaling theories and opens a venue for further research., (Creative Commons Attribution license.)

Freestanding membrane built from interwoven carbon fibers with encapsulated liquid gallium (Ga) nanodroplets has been demonstrated via the ultrasonic cell disrupting and electrospinning approaches along with a subsequent annealing process. Employing this membrane as a freestanding anode for lithium storage, the severe volume changes of Ga can be effectively accommodated due to the unique encapsulated 3D network structure. As a result, the membrane exhibits superior electrochemical performance, including high reversible capacity (450 mAh g −1 ), enhanced cycling stability (247 mAh g −1 at 0.65 A g −1 over 250 cycles), as well as good rate performance (200 mAh g −1 at 2 A g −1 ). [ABSTRACT FROM AUTHOR]

A new method for flux-free diffusion joining of aluminum matrix composites reinforced with SiC particles (SiCp/Al MMCs) in atmosphere environment has been developed. Liquid gallium and nano-copper particles were employed as filler metal under joining temperatures ranging between 400 °C to 480 °C, with a holding time of 2 h and pressure of 3 MPa. The results showed that 65 vol.% SiCp/6063 Al MMCs were successfully joined together. X-ray diffraction (XRD) analysis confirmed the presence of Ga2O3 at the fracture. Meanwhile, neither copper oxide nor aluminum oxide was detected. The formation of Ga2O3 can protect nano-copper particles and SiCp/6063 Al MMCs from oxidation. The width of weld seam tended to be narrowed from 40 μm to 14 μm gradually with increasing temperature from 400 °C to 480 °C. The maximum shear strength level of 41.2 MPa was achieved with a bonding temperature of 450 °C. The change of the strength was due to the adequate elements’ mutual diffusion and solution, as well as the change of the quantity and morphology of intermetallic compounds in the weld seam, such as Al2Cu and Cu3Ga. When the diffusion joining temperature reached 440 °C or above, the leak rate of the specimen remained under 10−10 Pa·m3/s.

Traveling magnetic field is one of effective tools for controlling phase change processes in metals. A better understanding of electromagnetic impact in such applications can help to improve and simplify technological processes. In this paper, numerical and experimental study of the electromagnetic force generated by traveling magnetic field and its ability to control liquid gallium flow and, consequently, affect the characteristics of solidification and melting processes are evaluated. Three-dimensional numerical model for calculating the magnetic field distribution and electromagnetic force acting on liquid gallium in a laboratory-size rectangular cavity was analyzed. Specific values of the TMF impact were chosen for the cases of interest in order to use such impact in our further work with horizontal gallium solidification process. The traveling magnetic field inductor was designed and built for making appropriate measurements and validating calculations. The analysis was focused on the electromagnetic force and the obtained velocity field. The experimental setup included an ultrasonic Doppler velocimeter for noninvasive measurements of the velocities of liquid metal flow. The comparison of computations with the experiments has shown a good agreement. [ABSTRACT FROM AUTHOR]

Temperature-dependent atomistic structure evolution of liquid gallium (Ga) has been investigated by using in situ high energy X-ray diffraction experiment and ab initio molecular dynamics simulation. Both experimental and theoretical results reveal the existence of a liquid structural change around 1000 K in liquid Ga. Below and above this temperature the liquid exhibits differences in activation energy for self-diffusion, temperature-dependent heat capacity, coordination numbers, density, viscosity, electric resistivity and thermoelectric power, which are reflected from structural changes of the bond-orientational order parameter Q 6 , fraction of covalent dimers, averaged string length and local atomic packing. This finding will trigger more studies on the liquid-to-liquid crossover in metallic melts. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulation has been employed to study the wetting transitions of liquid gallium droplet on the graphene surfaces, which are decorated with three types of carbon nanopillars, and to explore the effect of the surface roughness and morphology on the wettability of liquid Ga. The simulation results showed that, at the beginning, the Ga film looks like an upside-down dish on the rough surface, different from that on the smooth graphene surface, and its size is crucial to the final state of liquid. Ga droplets exhibit a Cassie–Baxter (CB) state, a Wenzel state, a Mixed Wetting state, and a dewetting state on the patterned surfaces by changing distribution and the morphology of nanopillars. Top morphology of nanopillars has a direct impact on the wetting transition of liquid Ga. There are three transition states for the two types of carbon nanotube (CNT) substrates and two for the carbon nanocone (CNC) one. Furthermore, we have found that the substrates show high or low adhesion to the Ga droplet with the variation of their roughness and top morphology. With the roughness decreasing, the adhesion energy of the substrate decreases. With the same roughness, the CNC/graphene surface has the lowest adhesion energy, followed by CNT/graphene and capped CNT/graphene surfaces. Our findings provide not only valid support to previous works but also reveal new theories on the wetting model of the metal droplet on the rough substrates.

Ruoff and co-workers recently demonstrated low-temperature (1193 K) homoepitaxial diamond growth from liquid gallium solvent. To develop an atomistic mechanism for diamond growth underlying this remarkable demonstration, we carried out density functional theory-based molecular dynamics (DFT-MD) simulations to examine the mechanism of single-crystal diamond growth on various low-index crystallographic diamond surfaces (100), (110), and (111) in liquid Ga with CH 4 . We find that carbon linear chains form in liquid Ga and then react with the growing diamond surface, leading first to the formation of carbon rings on the surface and then initiation of diamond growth. Our simulations find faster growth on the (110) surface than on the (100) or (111) surfaces, suggesting the (110) surface as a plausible growth surface in liquid Ga. For (110) surface growth, we predict the optimum growth temperature to be ∼1300 K, arising from a balance between the kinetics of forming carbon chains dissolved in Ga and the stability of carbon rings on the growing surface. We find that the rate-determining step for diamond growth is dehydrogenation of the growing hydrogenated (110) surface of diamond. Inspired by the recent experimental studies by Ruoff and co-workers demonstrating that Si accelerates diamond growth in Ga, we show that addition of Si into liquid Ga significantly increases the rate of dehydrogenating the growing surface. Extrapolating from the DFT-MD predicted rates at 2800 to 3500 K, we predict the growth rate at the experimental growth temperature of 1193 K, leading to rates in reasonable agreement with the experiment. These fundamental mechanisms should provide guidance in optimizing low-temperature diamond growth.

Employing a gallium-based passive decay heat removal system (PDHRS), which enables the use of water as an ultimate heat sink, was proposed for the UCFR-100. The gallium-based PDHRS has replaced the previous sodium-based PDHRS. To evaluate the safety and thermal performance of the gallium-based PDHRS, safety analysis and heat exchanger tests were performed. The safety analysis, using both deterministic and probabilistic analyses methods, confirmed the unique safety feature of the UCFR-100. The transient analysis for design basis accidents showed the rapid cooling characteristic of the gallium-based PDHRS of the UCFR-100. In addition, compared with the sodium-based PDHRS, the probabilistic safety analysis, using the level-1 Probabilistic Safety Assessments method, showed the significant decrease of the minimal cut sets and the significant reduction of the failure probability of the gallium-based PDHRS of the UCFR-100. Finally, compared with the sodium-to-air feature in the sodium-based PDHRS, the gallium-to-water heat exchanger in the gallium-based PDHRS enhanced the heat transfer performance and facilitated economic advantages to the entire system. In conclusion, the gallium-water PDHRS represented risk reduction of the entire reactor system with the effective thermal performance. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Liquid Ga could be used as a flexible heat-transfer medium or contact medium in the synchrotron-radiation-based instruments. The chemical stability of liquid Ga on other metal surface determines the serviceability of liquid Ga. In this paper, the oxidation evolutions of liquid Ga on Ni and Cu substrates have been investigated by in-situ grazing incidence small angle X-ray scattering (GISAXS) as a function of substrate temperature. The liquid Ga on Ni and Cu substrates shows different oxidation behaviors. A successive and slower oxidation from oxide clusters to oxide layer takes place with temperature increasing from 25 to 190 °C on the surface of the Ga/Ni/Si specimen, but a quick oxidation occurs on the entire surface of the Ga/Cu/Si specimen at the initial 25 °C. The subsequent heating increases the surface roughness of both liquid Ga, but increases simultaneously the surface curvature of the Ga/Cu/Si specimen. The understanding of the substrate-dependent oxidation behavior of liquid Ga is beneficial to its application as a heat-transfer medium. [ABSTRACT FROM AUTHOR]

[Display omitted] Gallium traditionally comprises a difficult object for theoretical description due to its complex short-range order structure. In this paper, deep learning potential for liquid gallium was developed, which allowed to significantly increase spatiotemporal scale of molecular dynamics (MD) simulation with preserving ab initio accuracy. Such increasing of performance of MD simulations allowed to calculate temperature dependence of viscosity value for liquid Ga, for which there is a considerable ambiguity in the available literature data, especially in low temperature range. Since direct ab initio viscosity calculations are not possible, as they do not allow enough statistical data to be collected, we combine several theoretical approaches: ab initio MD, for the implementation of which we used the VASP program code; the method of artificial neural networks (ANN) to obtain an effective interatomic interaction potential (ANN potential) using the DeePMD program; a classical MD method (LAMMPS program code); and the recently proposed viscosity calculation approach – time-decomposition method, which uses averaging over a large number of trajectories obtained by the MD. Ab initio MD calculations for liquid gallium were conducted in a temperature range from 303 to 1400 K (500 atoms were used in a supercell and 10,000 of 1 fs steps were performed for each temperature). The obtained data for the surface of potential energy and forces acting on atoms were used as a training set for constructing the ANN potential, whose high quality is confirmed by its almost ideal reproduction of ab initio structure at the level of pair correlations. In turn, the ab initio radial distribution functions are close to the results of other works. Self-diffusion coefficient, calculated via MD with developed deep learning potential, coincides well with the theoretical and experimental results of other authors. Temperature dependence of the viscosity was also computed via MD with developed potential using 10 independent trajectories (4000 atoms and 200,000 fs each) for every temperature point. Calculated viscosity data is in a good agreement with literature data at high temperatures, however at low temperatures some literature data agrees with our computational result, while the others – not. To check the results of our simulation, we experimentally measured viscosity from the melting point to 1270 K using an original setup based on oscillating cup method. Obtained experimental results are in excellent agreement with the results of our simulations. Thus, since both methods (experimental and computational) are modern and independent, presented at this work temperature dependence of viscosity is probably the most reliable at this moment. [ABSTRACT FROM AUTHOR]

Laboratory experiments using liquid metals and nonmetallic liquids reveal a rich set of dynamical processes active in Earth's core and in the cores of other terrestrial planets. These processes include thermochemical convection and a variety of instabilities driven by irregularities in rotation, such as precession, libration, and tides. The spectrum of fluid motions in these experiments ranges from turbulence and inertial wave motions at high frequencies to global-scale zonal flows at low frequencies, and they result from the interplay between buoyant forces, rotational effects, melting and solidification, magnetic fields, and the spherical geometry of the core. This review summarizes strengths and limitations of laboratory fluid experiments for modeling core dynamics, identifies the key physical parameters, and highlights recent advances in understanding the complex flows that control the evolution of the core. Special emphasis is given to ongoing efforts to develop self-sustaining fluid dynamos. [ABSTRACT FROM AUTHOR]

Abstract: With increasing demand for higher computational speed and emerging microsystems, efficient thermal management is need of the hour. Microchannels using liquid coolant are apt solution to this problem. Their efficiency depends greatly upon channel''s cross-section and liquid media. In this study the performance of trapezoidal (with two configurations A and V-type) and rectangular microchannels are analyzed and compared for two different coolants, liquid gallium and water. Performance is compared on the basis of maximum temperature at heated surface. For water as coolant the performance of rectangular type is found to be superior in terms of both flow rate and pump power. For liquid gallium as a coolant, microchannels having A-type cross-section is found to be performing better followed by V-type then rectangular type at same flow rate. However on comparison on basis of pump power the rectangular type of geometry is found to be more suitable. [Copyright &y& Elsevier]

Abstract: Many innovative laboratory experiments have been used to investigate the fluid dynamics of the Earth’s core. Experiments with liquid metals and non-metals range from turbulence and waves in the outer core to creeping flow in the inner core, and include the effects of rotation (steady and variable), thermal and chemical convection, spherical geometry, magnetic fields, melting and solidification. In this review, the strengths and limitations of laboratory fluid experiments are analyzed by comparing their dynamical similarity with the corresponding geophysical processes in the core. Recent advances in several areas are highlighted, including variable rotation dynamics, convection in liquid metals, the effects of magnetic fields on fluid motions, experimental dynamos, flow in the solid inner core, and metal–silicate interactions during core formation. [Copyright &y& Elsevier]

To better understand the heat-transfer character and flow of liquid gallium, a natural convection flow of liquid gallium was numerically simulated by using single phase method on the heat transfer of liquid gallium in a two dimensional enclosure. The effects of boundary condition and Grashof number on the flow and the convective heat transfer behavior are investigated. The numerical results which include temperature and velocity graph are compared with the experimental data and reasonable agreement is achieved. In a case that thermal conductivity takes a leading part, when Grashof number goes up, convection will gradually play a more important role. [ABSTRACT FROM AUTHOR]

Abstract: Ga–pWSe2 Schottky diodes have been fabricated by making contact of liquid gallium on pWSe2 surfaces. The stability and phase transition of the diodes were investigated in terms of barrier height, ideality factor and series resistance using thermionic emission model by current–voltage method. The anomalous behaviour of these parameters during the initial hours of fabrication is interpreted in terms of the phase related transition of gallium from liquid to solid. Beyond this time period, diodes show stable nature in its parameters. [Copyright &y& Elsevier]