In the current work, we evaluate the influence of the processing parameters on the electrical properties of aluminium zinc oxide (AZO) thin films produced by airbrush spray-pyrolysis deposition technique. Spray-deposited AZO thin-films were produced with Al:Zn molar ratios varying from 0 % (pure ZnO) up to 30 %, using aluminium acetate and zinc acetate as organic precursors and water as solvent. Thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR-ATR) were used to monitor the metal-oxide formation from the organic precursors as a function of the temperature. The results show that a temperature of 400 °C is necessary to completely degrade the organic phase and to obtain the desired inorganic metal-oxides films. The electrical properties of the TMOs were evaluated by d.c. current-voltage (I-V) analysis using planar thermally evaporated Al electrodes on top of the TMO layer, with different aspect ratios (1/18, 2/9, 5/13, 5/9 and 8/9). The lowest sheet resistance was obtained for AZO films at a molar Al concentration of 5 %. We also observed that, after carrying out a post-annealing treatment (30 mbar, 150 °C) the samples presented a decrease on the sheet resistance superior to 60 %, in comparison to the samples before the treatment.

Here we report the use of luminescence thermometry to measure the temperature decay from single gold structure into the substrate of AlGaN:Er3+ film. We looked at Er3+ ion photoluminescence upon illumination by modulated 532 nm laser and recorded time-resolved luminescence of 2H11/2 → 4I15/2 and the 4S3/2 → 4I15/2 energy transitions. We calculated the heat generated from gold microdisk and observed the rate of heat dissipation to the environment. We directly calculated the absolute thermal conductivity of 1.7 W/mK for AlGaN: Er3+ film which was in agreement with the literature.

For the UK geological disposal facility (GDF) concept in a high strength crystalline rock, Nirex Reference Vault Backfill (NRVB) has been considered to use as a cementitious backfill material. The lifetime performance of this high pH material is required to be extremely long, and as a consequence of the interaction with the geological environment (e.g. groundwater), the backfill material will evolve and age with time. In this paper, we present the results of a leaching experiment, where NRVB is placed in contact with three different groundwater compositions representative of granitic, clay and saline groundwater for 35 days. Some differences were observed related with the mineralogy. X-ray Diffraction results showed the formation of more ettringite, mainly in the NRVB samples leached in clay and saline groundwater. An increase of the pH was also observed in the NRVB samples leached with the three different ground waters, being these results in accordance with the reactive transport modelling performed.

Three dimensional X-ray diffraction (3DXRD) microscopy is a powerful technique that provides crystallographic and spatial information of a large number, of the order of thousands, of crystalline grains in a sample simultaneously. A key component of every 3DXRD microscopy experiment is the near field detector that provides high resolution spatial information of the grains. In this work we present a novel design for a semi-transparent, 16 megapixel near field detector. As opposed to a typical single scintillator phosphor detector, this design, we call the Quad Near Field Detector, uses four quadrants. It has a total field of view is 5.3 mm x 5.3 mm with an effective pixel size of 1.3 µm x 1.3 µm. The detector’s relatively large field of view can be used to obtain higher order diffraction spots which we anticipate will lead to improved spatial resolution in grain reconstructions. The large field of view can also enable the detector to be positioned further from the sample, in this way increasing the working distance and enabling larger environmental cells for in-situ studies. Many alignment parameters can be resolved by careful mechanical design. For this reason a novel translation stage for focusing the microscopes was developed, tested, and implemented. The near field detector was calibrated and characterized at the Cornell High Energy Synchrotron Source. The operational feasibility of such a multi-plate detector demonstrated in this work paves the way for new technologies in instrumentation of 3DXRD microscopy.

The synthesis of Platinum (Pt) nanoparticles by gamma irradiation is presented. The 0.1 M Pt solution of different concentration was prepared from K2PtCl4. The platinum aqueous solutions were irradiated by gamma radiation at a dose of 70, 90 and 120 kGy. The findings show the effect of irradiation on PtII solutions with different concentrations. The big black particles that are fairly agglomerated when the concentration was above 0.0050 M were observed. The UV-Vis spectrum of Pt of different concentrations shows a strong absorption peak at the wavelength 261 nm after irradiation, which indicates the presence of platinum nanoparticles. Furthermore, FTIR, XRD and HRTEM images also confirmed the presence of the nanoparticles produced by Radiolysis. The size of the Pt nanoparticles was found to be 7.39 nm.

For many years, comprehensive data demonstrate a persistent lack of interest in the field of science, technology, engineering and mathematics (STEM) among students in European and North American countries. This lack of interest is regarded as one reason causing underrepresentation of diversity, especially that of female students within the field of STEM. Obviously, students—although possibly highly talented—refrain from choosing STEM careers only because their attention is not sufficiently attracted to STEM at the right time at the right place. In particular, this fact significantly affects the field of material research and, therefore, identifying opportunities for sparking students’ interest in materials is a crucial challenge in the framework of a modern STEM education. Here, we present the outline of the novel project “Metal Matters”, which aims at establishing an interdisciplinary approach to foster the field of materials in education. In essence, our research focusses on the omnipresence of metal as material. By exploring the K-16 continuum, we aim to identify windows of opportunities for raising awareness of the relevance of materials. Our approach is to stimulate interest in the relevance of materials by explicitly promoting metal as a topic across the curriculum. Our project is deliberately not restricted to STEM, but also covers history, society, economy, health, sports, literature, and language. Here, we present one part of the project contrasting the scientific relevance of metal with the students’ ideas about metal. For the present exploration and data collection, we employed a mixed-method design consisting of linguistic frequency analysis of scientific publications as well as the qualitative analysis of students’ written responses and drawings.

Hydroxyapatite (HA)/nanotubular titanium dioxide (TiO2) composite coatings loaded with antibiotics were developed to combine biocompatibility and antibacterial property. TiO2 nanotubes were first fabricated on Ti plates using anodization techniques. Then HA nanocrystals were synthesized on the TiO2 nanotubes by electrochemical deposition, followed by loading of a model drug compound, streptomycin. The streptomycin release profile of the composite coating was investigated. Bacterial tests demonstrate that the streptomycin-loaded composite coatings were highly effective in inhibiting bacterial growth. Simulated body fluid (SBF) experiments indicated that the composite coatings possessed good osseointegration capability.

Cr-doped higher manganese silicides (HMSs) (Mn1-xCrx)Si1.75 (x = 0–0.35) have been prepared by repeated sintering from raw elemental powder using spark plasma sintering. The a- and cMn-axis length increases with increasing Cr content x. The results of powder X-ray diffraction and microstructural observation suggest that impurity phases, e.g. (Mn, Cr)Si and CrSi2, exist in the samples with x = 0.20 or above. The electrical resistivities and Seebeck coefficient decrease with increasing Cr content x. The Cr content x of 0.10 indicated the largest power factor at 850 K (1.39×10-3W/mK), followed in order by x of 0.25, 0, 0.05, 0.15, 0.20. To confirm the effect of Cr-doping on outputs of modules, two paired p-n modules consisting of n-type purchased Mg2Si and p-type Cr-doped HMS with x = 0, 0.05, 0.10, and 0.20 elements were prepared. The module consisting of (Mn0.9Cr0.1)Si1.75 showed the highest output, that is, 845 mW at 873 K on the hot side. There was approximately 8% improvement compared with that of the module consisting of Cr-free elements.

Demand for newer, stronger, stiffer, yet lighter-weight and environmental friendly (biodegradable) materials in the fields such as automobile for non-structural applications are ever increasing. The principal reasons for using natural (cellulosic) fibers is they possess several attractive properties such their economic feasibility, enhanced sustainability, good specific mechanical properties, and desirable aspect ratio for good performance after melt-processing. Natural fiber composite materials are now being rapidly utilized in automobile industries, and they have become the forefront of research and development activity. An interesting alternative for reinforcing soft polymeric matrices with short fibers is the use of cellulose fibers which show remarkable reinforcing effects in thermoplastics such as polypropylene. The current study made an attempt to investigate the suitability of sisal fibers for automobile industry for non-structural and low-strength interior applications. In this work native sisal fibers were extracted and the effect of alkali treatment on their morphological, tensile, moisture absorption and thermal properties were studied. Scanning electron micrographs indicated roughening of the surface of the fiber strands due to the removal of the hemicellulose layer on alkali treatment. The maximum weight-gain for the composite prepared from treated fibers was 2.12 %, while that for the composite prepared from untreated fiber was 4.33 %. From the thermograms, the results indicate initial degradation for the treated fiber to have improved from 174 °C to 230 °C (56 °C shift) when compared to the untreated fiber. This fiber has competitive advantages when evaluated with other natural fibers. A polymer composite was processed from the chemically modified fiber, profiled against equivalent material systems in Ashby material property charts exhibited its suitability for light, low strength and low flexure material applications which can use a potential replacement of fibres being used currently.

We report on the exploration of perpendicular exchange bias in iron platinum/nickel oxide (FePt/NiO) bilayer thin films grown using pulsed laser deposition (PLD) on MgO (100) substrates. Exchange bias is an important property for giant magnetoresistance, and, as such has promise for applications in spin valves, magnetic sensors and magnetic random access memory. The magnetic L10 phase of FePt is known for having high perpendicular magnetic anisotropy, tunable coercivity/grain size and large magnetic storage density. The FePt layer was first deposited directly on MgO, followed by the deposition of the NiO layer on top of the FePt layer. The coercivity of the L10 FePt layer was tuned during growth to form a hard or soft magnetic layer. The FePt/NiO thin films grown for this study exhibit perpendicular exchange bias at 5K, as quantified using our SQUID measurements. XRD confirms parallel plane ordering between the MgO (200), FePt (002) and NiO (111) atomic planes while cross sectional TEM confirms the epitaxial growth of L10-FePt(001)<100>//MgO(100)<001> and the preferential growth of NiO on top of the FePt. Films of only FePt were grown to examine the surface architecture of the ferromagnetic layer and thus the interface of the FePt/NiO bilayer. The results from our XRD, TEM and magnetometry characterization of the FePt films and FePt/NiO bilayer thin films will be discussed.

The formation mechanism and chemical form of insoluble C-14 found in PWR need to be examined in order to predict its environmental behavior after disposal. This study investigates the alteration of ion-exchange resin by heating and irradiation, because past studies indicated the ion-exchange resin may be the origin of insoluble C-14.

Resin was heated at 300 °C in solution with low oxygen content to simulate the environment of PWR coolant. The sulfo group was found to detach within 8 h, and structures similar to polystyrene were remained. This is followed by detachment of H from the alkyl group, condensation reaction, and the formation of amorphous carbon-like structure. After heating for 24 and 96 h, the resin was irradiated by 60Co γ-rays in the solution. The FT-IR and TG measurements after irradiation suggested that OH and COOH groups were formed on the surface of the resin. These functional groups may be involved in reactions that finally form the amorphous carbon.

In addition, the characteristics of heated and irradiated resin were compared to real insoluble-C (CRUD) sample in PWR (in Appendix).

We developed a new type of polymer descriptor based on Extended Connectivity Fingerprints. The number densities, that are substructure numbers divided by the number of atoms in a polymer model, were employed. We found that this approach is superior in accurately predicting linear polymer properties, compared to the conventional approach, where just the substructure numbers are used as descriptors. In addition, dimension reduction and multiple replication of repeat unit were found to improve prediction accuracy. As a result, the novel descriptor based on the Extended Connectivity Fingerprints with machine learning approaches was found to achieve accurate prediction of the refractive indices of linear polymers, which is comparable to that by ab initio density functional theory. Although process-dependent properties such as mechanical properties were difficult to predict, the present approach was found to be applicable to prediction of substructure-dependent properties, for example, optical properties, thermal stabilities.

In recent years, the graphene/metal nanoparticles (NPs) hybrids have sparked burgeoning interest in varied application fields due to its unique physicochemical properties. In this paper, we present an overview of preparation methods of the graphene/metal NPs hybrids, which includes some common routes as well as other particular strategies. In addition, we introduce a novel physical route to decorate metal NPs upon graphene sheets. Our expectation is that this review will provide references for the exploitation of emerging preparation technologies, and expand application fields for graphene/metal NPs hybrids in the future.

Simple and efficient approach for artificial photosynthesis of CO2 reduction into ethanol with flexible functional multi-layered membrane catalysts is suggested. The g-C3N4 and BiVO4 particle were synthesized by self-condensation and hydrothermal method. g-C3N4 membrane catalyst and g-C3N4/BiVO4 layered membrane catalyst were fabricated by casting and shaping of Nafion polymer mixture. XRD, FT-IR and XPS analyses proved that the intrinsic properties of g-C3N4 and BiVO4 were maintained after fabricating flexible functional multi-layered membrane catalyst. The interfacial contact between g-C3N4 and BiVO4 particles in flexible membrane catalyst for efficient transport of photogenerated electron was revealed by TEM and photoelectrochemical analysis. Finally, photochemical CO2 reduction reaction was performed with flexible functional multi-layered membrane catalysts. The g-C3N4 membrane catalysts produced 147 μM of ethanol during 12 hrs of CO2 reduction reaction while the g-C3N4/BiVO4 layered membrane catalysts produced 256 μM of ethanol during 12 hrs of CO2 reduction reaction. This is due to the higher solar light harvesting and efficient hole-charge separation from functional multi-layered BiVO4 membrane catalyst leading to the higher electron transport rate to g-C3N4 membrane catalysts, promoting the CO2 reduction reaction on the surface of g-C3N4 membrane catalyst.

Point-of-care systems require highly sensitive, quantitative and selective detection platforms for the real-time multiplexed monitoring of target analytes. To ensure facile development of a sensor, it is preferable for the detection assay to have minimal chemical complexity, contain no wash steps and provide a wide and easily adaptable detection range for multiple targets. Current studies involve label-free detection strategy for relevant clinical molecules such as heme using G-quadruplex based self-assembly. We have explored the measurement of binding and kinetic parameters of various G-quadruplex/heme complexes which are able to self-associate to form a DNAzyme with peroxidase mimicking capabilities and are critical to nucleic acid research. The detection strategy includes immobilizing the G-quadruplex sequences within a polymer matrix to provide a self-assembly based detection approach for heme that could be translated towards other clinically relevant targets.

Lithium ion batteries with high-rate performance have been demanded since electric and hybrid vehicles are released. It is known that high interfacial resistance between electrode and electrolyte prevents intercalation of lithium ions. We investigated high-rate capability of typical LiCoO2 cathode with various surface morphologies using epitaxial thin films prepared by pulsed laser deposition. As a result, high-rate performance in (104)LiCoO2 thin films was enhanced by an increase of (110)LiCoO2 facet density because diffusion coefficient of (110)LiCoO2 was larger than that of (104)LiCoO2. Therefore, a control of crystal plane at the surface is a key point for high-rate performance.