The thermoelectric properties of polycrystalline samples of Sr1-xLa0.67xTiO3-δ and Sr0.20La0.53Ti1−yNbyO3-δ have been investigated. The first series has a gradually increasing amount of A-site vacancies, and charge carriers linked to the oxygen deficiency. The second series has a fixed amount of A-site vacancies (27%) and variation of the Nb content was used to optimise the electrical properties. Maximum power factors of 0.6 mW m-1 K-2 for x = 0.4 and 0.4 mW m-1 K-2 for y = 0.05 were observed at 700 K. Combining these values with thermal conductivity data obtained previously, suggests that maximum figures of merit zT = 0.16 for x = 0.4 and zT = 0.2 for y = 0.05 are possible at 1000 K. This study contributes new insight on the interplay between A-site vacancies and thermoelectric performance in SrTiO3.

Over the last decade, the explosion in research and Development associated with nanoscalar materials has continued apace. In parallel with this has been the rapid rise of both sustainable materials and, as a consequence, Natural, Cellular and Responsive material systems. Many of these originate from inorganic, inorganic-organic hybrid composites and polymeric and bio-nano polymeric systems which exhibit intrinsic physico-chemical properties that can be classed as ‘soft’. That is flexible, malleable, lightweight, transparent or semi-transparent and stretchable in character and which can also offer both biocompatible and bioresorbable characteristics essential to useable and sustainable material systems.

This paper describes some of the ways in which we are beginning to understand, explain and exploit ‘soft’ technology. In particular the interactive role of creative design and innovative material science linked through new fabrication methodologies that have, as their common purpose, a focus on compelling Human centred needs. Examples are health, wellness, ambient assistance and urgent improvements in cleanliness, hygiene and nutrition.

A trend in the operation of nuclear power reactors is the increase in discharge burnup of the fuel. Intrusion of groundwater in a failed canister of a future deep repository is expected to occur in the presence of hydrogen, produced by the anoxic corrosion of iron and by radiolysis of water. Compelling evidence now exists that hydrogen inhibits oxidative dissolution of irradiated nuclear fuel or alpha doped UO2, however the number of studies involving high burnup fuel are limited. In the experiment PWR UO2 fuel with a burnup of ∼75 MWd/kgU was leached in simulated groundwater (10 mM NaCl, 2 mM NaHCO3) at room temperature under 5 MPa of hydrogen. Since the main objective was to investigate the fuel matrix dissolution, a fuel fraction that had previously been leached for over one year was reused. The U-238 and Tc-99 concentration was found to vary in the samples taken over 1100 days of leaching, depending on the degree of centrifugation. The erratic behavior of this autoclave experiment is tentatively attributed to a high surface area, with sub-micrometer sized fuel particles adhering to larger fuel fragments (evidenced by electron microscopy), caused by the fuel milling at the start of the experiment. This likely promoted an increased amount of pre-oxidation of the fuel as well as the potential for reductive precipitation and subsequent release of colloids from the autoclave. As a comparison, initial results from an ongoing autoclave experiment with coarser fuel fragments are also given.

The Polymer Electrolyte Membrane Fuel Cells (PEMFCs) platinum catalyst’s susceptibility to poisoning by carbon monoxide (CO) reduces its output power. In an effort to diminish poisoning, gold and platinum nanoparticles were incorporated onto partially reduced graphene oxide (Au/Pt-prGO) sheets to reduce both nanoparticle aggregation and the amount of precious metal needed. Applying this material onto the electrodes and Nafion membrane of a PEMFC was hypothesized to increase CO tolerance as well as power output.

Aliquots of graphene oxide (GO) were functionalized with platinum and/or gold nanoparticles using a simple desktop synthesis at room temperature. Partial reduction with NaBH4 maintained hydrophilic solubility. Test solutions applied to electrodes and to electrodes + Nafion membrane were first tested in a PEM fuel cell with a pure H2 gas feed and then repeated with a H2 gas feed containing 1000 ppm of CO. Test arrangements averaged doubling the output power of the poisoned control, with the most effective yielding an output power ∼250% that of the poisoned control. Additionally, each system’s poisoned output power (PP) was compared to its highest possible output power (PM), with the most effective setup showing no reduction in output power, even with a H2 gas feed containing 1000 ppm of CO. Thus, this offers promise of a simple, cost-effective method of both improving PEMFC power output while reducing or even eliminating CO poisoning at room temperature.

EURO-GANEX aims to recycle both major and minor actinides. As the final waste composition is free from actinides, adapted immobilization matrices should be developed. Synroc is a potential wasteform that has proven itself to be efficient in immobilizing high-level wastes (HLW). In this study, a new composition of Synroc, Synroc-Z, is designed and characterized. The key modification is in decreasing the amount of zirconolite phase, which is the main host phase for actinides and increasing the amount of other phases (hollandite and perovskite). As designed the obtained amount of zirconolite is lower than in Synroc-C compositions. Synroc-Z samples were synthesized with a waste loading of 20 wt.% at various temperatures and pressures via hot-pressing to determine the optimum process parameters, which were determined to be 1150-1200°C and 20 MPa, respectively.

Given their low toxicity and natural presence in the human diet, selenium nanoparticles have been established as potential candidates for the treatment of numerous cancers. In this study, red-allotrope selenium nanoparticles (rSeNPs) were synthesized and characterized. Head and neck squamous cell carcinoma (HNSCC) and human dermal fibroblast (HDF) cell lines were cultured and exposed to rSeNPs at concentrations ranging from 0.01 to 100μg rSeNP/mL media for one to three days. The cytotoxicity of rSeNP towards HNSCC and HDF was analyzed. Results indicated that the particles were approximately four times as cytotoxic toward HNSCC compared to HDF, with their respective IC50 values at 19.22 and 59.61μg rSeNP/mL media. Using statistical analysis, an effective dosage range for killing HNSCC cells while simultaneously minimizing damage to HDF over a three-day incubation was established as 20 to 55μg rSeNP/mL media. Such results indicate that rSeNPs are a potential option for treating HNSCC. Due to its ability to minimize nanoparticle agglomeration, making a it a candidate with which to functionalize selenium, similar assays were performed using poly(ethylene glycol) with a molecular weight of 200g/mol (PEG200), with results indicating that only a slight cytotoxic effect exists for HNSCC and almost no effect for HDF.

We studied TAGzT theoretically using density functional perturbation theory within the plane-wave-pseudo-potential formalism and experimentally by Raman and IR spectroscopy at ambient and high pressure. The modeled spectra predict reasonably well the experimental spectra at ambient pressure and the Raman vibrational modes at pressures up to 25 GPa. We report the effects of pressure on volume, Raman and IR vibrational modes, and charge distribution of TAGzT.

The structural and electronic properties of lead chalcogenides PbX (X=S, Se, and Te) are investigated by first-principles calculations based on the range-separated hybrid functionals and semilocal generalized gradient approximation. It is found that an accurate band structure description requires the hybrid functional with the spin-orbit coupling included. Using this approach, the band structure of lead telluride and doped lead selenide are calculated, and its influences on the transport properties are discussed.

Macroscopic and microscopic photovoltage characteristics of detonation nanodiamonds (DNDs) with distinct surface terminations are presented. Organic photodiodes are fabricated based on P3HT+DNDs mixture (50 wt%). We compare effect of hydrogen and oxygen termination of DNDs. Compared to photodiodes without DNDs the current-voltage characteristics of photodiodes with O-DNDs in dark and under AM 1.5 illumination show reduced dark current, and higher photocurrent and open circuit voltage. H-DNDs shunt the photodiodes, which is attributed to their surface conductivity. Kelvin probe force microscopy detects a reproducible photovoltage of around 5 mV generated by a green laser (532 nm) on both types of pristine DNDs. Thus although conductivity of H-DNDs may represent a problem for photodiodes, both types of DNDs alone can function as miniature energy conversion devices.

Mg, the only effective p-type dopant for nitrides, iswell-studied in thin films due to the important role the impurity plays in lightemitting diodes and high power electronics. However, there are few reports of Mgin thick free-standing GaN substrates. Here we evaluate the material quality andpoint defects in GaN grown by hydride vapor phase epitaxy (HVPE) using metallicMg as the doping source. The crystal quality is typical of commercially grownHVPE substrates, and the photoluminescence measurements reveal distinctivelysharp excitonic and shallow-donor shallow-acceptor features. Secondary ion massspectroscopy indicates total Mg concentrations between 7x1016 and6x1018 cm-3 in the four separate samples studied but,more significantly, photoluminescence and electron paramagnetic resonancespectroscopy show that the Mg is incorporated as a shallow acceptor.

One important approach to increasing High magnetic fields (HMF) beyond what is now possible is to improve the properties of various composite materials used as both conductors and structural support. Typical conductors for high field magnets are Cu-based metal-metal composites. To achieve high mechanical strength, these composites are fabricated by cold deformation, which introduces high densities of interfaces along with lattice distortions. During the operation of a magnet, mechanical load, high magnetic field, extreme temperatures and other stressors are imposed on the materials, causing them to be further “processed”. The composite conductors in a magnet, for example, may undergo high temperatures, which reduce lattice distortions or soften the material. At the same time, HMF may increase lattice distortion, leading to a complex change in interface characteristics. Both the mechanical properties of the conductors, like the tensile and yield strength, and the electric conductivity of the composites are closely connected to changes in lattice distortion and interface density. Understanding these changes helps us to assure that materials can operate in optimized conditions during most of magnets’ service life. Maximizing service life is critical, given the high cost of building and operating high field magnets. The goal of this paper is to 1) show our understanding of changes that occur in the properties of selected materials during the fabrication and under HMF and 2) to discuss how those changes relate to the microstructure of these materials and consequently to the service life of high field magnets.