materials

Spent nuclear fuel oxidation under dry storage controlled conditions for studying its radial oxidation behaviour

Researchers at CIEMAT, Spain and JRC, Germany have recently published a study exploring the potential risks of storing highly-irradiated spent nuclear fuel when the fuel oxidises. A Linkam THMS600 stage was used to accurately control the temperature under a flow of dried air. Time-resolved Raman spectra were obtained from different locations on the uranium pellet, over the course of several days. Changes between different regions were proposed to be a result of higher local burn up of the oxidation products caused by increased fission. This work could help to reduce the dangers of storing spent nuclear fuels.

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High temperature anomalous Raman and photoluminescence response of molybdenum disulfide with sulfur vacancies

MoS2 is a two-dimensional crystal that belongs to the family of transition metal dichalcogenides (TMDCs), which are materials composed of a transition metal atom (such as Mo, W, Nb, etc.) and two chalcogen atoms (such as S, Se, Te, etc.). TMDCs have attracted a lot of attention in recent years because of their diverse and tunable properties, such as semiconductivity, metallicity, and magnetism. MoS2 is one of the most studied TMDCs because it has a direct bandgap in the monolayer limit, which makes it suitable for optoelectronic and photovoltaic applications. MoS2 also exhibits strong light-matter interactions, spin-orbit and Coulomb interactions, valley-selectivity, and superconductivity under certain conditions. The optical properties of MoS2 depend on various factors, such as the number of layers, the stacking order, the presence of defects, the choice of substrate, the temperature, the strain, the doping level, and the applied magnetic field. Raman and photoluminescence (PL) spectroscopy are powerful techniques to probe these optical properties and reveal the underlying physics and mechanisms of MoS2 and other TMDCs.

Using a Linkam HFS600E-PB4 to modulate the temperature, the researchers discovered an anomalous behaviour of the A1g mode in Raman spectra and an intensity enhancement in PL spectra of MoS2 with temperature, and explained them by considering sulfur vacancies and intervalley charge transfer.

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Crystallisation of Poly(lactic acid) under continuous shear conditions: Online X-ray analysis in isothermal conditions

A paper by Volpe and Pantani, published in Thermochimica Acta, reports on the use of the Linkam Shearing Cell CSS450 to investigate the effect of shear rate on the isothermal crystallisation of poly(lactic acid), ‘PLA’, a biodegradable aliphatic polyester produced from renewable resources. The CSS450 is a temperature-controlled stage that allows the application of a continuous shear flow to a sample while observing its microstructure evolution by hot stage microscopy or spectroscopy.

The researchers coupled the CSS450 with in situ X-ray diffraction measurements at a synchrotron source to study the crystallinity evolution of PLA during continuous shear at different shear rates. They found that increasing the shear rate induced a dramatic decrease of the half crystallisation times; more than one order of magnitude in the analysed range of shear rates. They also applied a model for the description of crystallinity evolution and found that the nucleation rate needed to describe the data is much larger than that measured in a previous work in the same range of shear rates. This study demonstrates the potential of the CSS450 for studying the flow-induced crystallisation of polymers and other materials under realistic processing conditions.

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Brillouin Light Scattering Characterisation of Grey Tone 3D Printed Isotropic Materials

3D direct laser writing technology is capable of producing polymer microstructures in a range of sizes, from nanometres to millimetres, with adjustable optical and elastic properties through grey-tone lithography. Researchers have characterized the temperature-dependent elastic constant of various reticulated isotropic polymers using Brillouin light scattering in a Linkam Stage.

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In situ study of the morphological changes on the surface of a duplex stainless steel by means of high temperature laser scanning confocal microscopy

Using the Linkam TS1500, researchers observe how duplex stainless steel undergoes morphological changes with temperatures close to its melting point. They heated samples up to 1500°C and captured images of the changing material using a confocal microscope. This research is essential work to help understand how heat treatments affect steel, in order to avoid inadequate heat treatment which leads to intergranular corrosion.

Read the full article here (access required).

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Investigation of the influence of pretreatment parameters on the surface characteristics of amorphous metal for use in power industry

Researchers use Linkam TS1500 to investigate the properties of “metallic glasses”, or amorphous metals, as they undergo annealing at high temperature. These materials are potentially useful for the production of high efficiency energy devices.

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Heterogeneous oxidation of amorphous organic aerosol surrogates by O3, NO3, and OH at typical tropospheric temperatures

Researchers use Linkam’s BCS196 Cryobiology stage with optical microscopy to observe and measuree reactive uptake coefficients (γ ) of O3, NO3, and OH for several systems of oxidant and organic aerosol surrogate combinations.

In situ study of sigma phase formation in Cr–Co–Ni ternary alloys at 800C using the long duration experiment facility at Diamond Light Source

See how a unique setup using Linkam’s TS1500 allows researchers to perform beamline XRD analysis at high temperature at Diamond Light Source. Here, they use the new long-duration experimental beamline I11 to study phase formation kinetics of metal alloys, demonstrating a new technique for metallurgical studies.

An Experimental Study of the Formation of Talc through CaMg(CO3)2–SiO2–H2O Interaction at 100–200∘C and Vapor-Saturation Pressures

Researchers use the Linkam CAP500 with fused silica capillaries to study the formation of talc, observing the process using techniques such as Raman spectroscopy and X-ray diffraction.

Access the PDF version here.

Full Open Access article available via CC BY 3.0.

Wan, Ye, et al. "An Experimental Study of the Formation of Talc through CaMg (CO3) 2–SiO2–H2O Interaction at 100–200 C and Vapor-Saturation Pressures." Geofluids 2017 (2017).

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