Investigation into the effect of Y, Yb doping in Ba2In2O5: determination of the solid solution range and co-doping with phosphate

In this paper we examine the effect of Y, Yb doping in Ba2In2O5, examining the solid solution range and effect on the conductivity and CO2 stability. The results showed that up to 35% Y, Yb can be introduced, and this doping leads to an introduction of disorder on the oxygen sublattice, and a corresponding increase in conductivity. Further increases in Y, Yb content could be achieved through co-doping with phosphate. While this co-doping strategy led to a reduction in the conductivity, it did have a beneficial effect on the CO2 stability, and further improvements in the CO2 stability could be achieved through La and P co-doping

A strategic support tool for the incorporation of societal benefits into toy design

This thesis reports on the research undertaken to embed positive social factors into strategic decision making of toy design and manufacturing. This is achieved by two objectives, the first and main objective of this research is to develop a framework which assess the societal benefits of products and enable the comparison of products based on their functionalities. The secondary objective is to develop a toolkit that incorporates the framework with existing sustainable assessment and product management strategies

Synthesis and characterization of oxyanion (phosphate, sulfate) doped Ba2_2Sc2_2−_-y_yGay_yO5_5

In this paper we examine the effect of partial substitution of Ga for Sc in the oxyanion (phosphate, sulfate) containing perovskites, Ba2Sc$_2$$_-$$_x$P$_x$O$_5$$_+$$_x$ and Ba$_2$S$_c$$_2$$_-$$_x$S$_x$O$_5$$_+$3$_x$$_/$$_2$ with the samples analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. The results demonstrate that in both cases, Ga can be incorporated in place of Sc up to 40%. In order to accommodate the increasing Ga content, a reduction in the oxyanion content is required. Thus for the highest Ga content sample achieved, only 10% oxyanion incorporation was achieved giving endmember compositions of Ba$_2$S$_c$Ga$_0$$_.$$_8$P$_0$$_.$$_2$O$_5$$_.$$_2$ and Ba$_2$S$_c$Ga$_0$$_.$$_8$S$_0$$_.$$_2$O$_5$$_.$$_3$ for phosphate and sulfate doping respectively. While the Ga doping was shown to significantly improve the stability of the systems towards CO$_2$ containing atmospheres, conductivity measurements showed a reduction in the conductivity with increasing Ga content

An integrated tool to support sustainable toy design and manufacture

Whilst the importance of considering the positive societal benefits of a product, in addition to other social, economic and environmental factors, has received wider recognition, its definition, concept, and integration into product design are not so well developed and studied. A literature review on sustainable design identified the potential of Social Life-Cycle Assessment as a tool to measure societal benefits of products; however further analysis of sustainable assessment methods highlighted the lack of a coherent definition and method for achieving this. This paper presents a framework for including societal benefits within a product portfolio management process and a prototype tool which aims to support the implementation of the framework within the toy industry, specifically on the societal benefit assessment of the products during the first stage. Finally a simulated case study of three toys is used to exemplify the intended application of this tool and to support the concluding discussions

Societal benefit assessment: an integrated tool to support sustainable toy design and manufacture

A framework and methodology for assessing the societal benefits of a product was developed based on the assertion that, in order to access future diminishing resources, manufacturers will need to demonstrate both the social and environmental benefits of their products. This paper follows on from this published research and presents an integrated tool to support the implementation of this framework and methodology within the toy industry during the design and development phase. A simulated case study is used to exemplify the application of this tool and to support the concluding discussions

New electrolyte materials for solid oxide fuel cells

Two general systems, brownmillerite-type Ba$_2$In$_2$O$_5$ and apatite-type silicates have been investigated for potential solid oxide fuel cell electrolyte applications. The combination of powder diffraction, NMR, TGA, Raman and AC impedance spectroscopy indicated the successful incorporation of phosphate, sulphate and silicate into the Ba$_2$In$_2$O$_5$ structure leading to a transition from an ordered brownmillerite-type structure to a disordered perovskite-type, which led to the conductivity enhancement below 800 °C, along with a significant protonic contribution in wet atmospheres. The CO$_2$ stability was also shown to be improved on doping. This oxyanion doping strategy has been extended to the analogous system, Ba$_2$Sc$_2$O$_5$, which resulted in samples with high conductivity and good stability towards CO$_2$. Neutron diffraction studies on La$_9$$_.$$_6$Si$_6$O$_2$$_6$$_.$$_4$ indicated that the interstitial oxide ion is located near the channel centre. Further interstitial anions could be accommodated through hydration, which led to displacement of the interstitial site away from the channel centre, with an accompanying swelling of the channel. Although long term annealing of these apatite silicates showed no apparent significant structural change, a reduction in the bulk conductivity was observed, while the grain boundary conductivity was improved, thus resulting in a small enhancement in the total conductivity below 400 °C

Synthesis and characterization of proton conducting oxyanion doped Ba2Sc2O5

In this paper we report the successful synthesis of the cubic oxyanion containing perovskites, Ba2Sc2-xPxO5+x (x=0.4, 0.5), with the samples analysed through a combination of X-ray diffraction, NMR, TGA, Raman spectroscopy and conductivity measurements. Conductivity measurements indicate a p-type contribution to the conductivity in oxidizing conditions at elevated temperatures, with evidence for proton conduction in wet atmospheres. For the latter bulk conductivities of 5.9 x 10-3 and 1.3 x 10-3 Scm-1 at 500○C were obtained for x=0.4 and 0.5 respectively, comparable to other perovskite proton conductors, while the stability towards CO2 containing atmospheres was improved compared to BaCeO3 based systems.\ud Related Si doped systems have also been prepared, although in this case small Ba2SiO4 impurities are observed. We also provide evidence to suggest that “undoped” Ba2Sc2O5 contains carbonate groups, which accounts for its thermal instability

Expanding the scope of LCA to include 'societal value': A framework and methodology for assessing positive product impacts

As resources become scarcer, efficiency improvements alone will not bridge the widening gap between supply and demand, resulting in the need for additional non-financial mechanisms to ensure the fairer allocation of resources. This paper asserts that, in the future, companies will need to demonstrate their products' positive contribution to society as well as minimising their negative environmental/soci al impacts. A review and analysis of existing tools and assessment methodologies identifies current capabilities and highlights the need for 'Societal Value' assessment that considers both quantitative and qualitative factors .This paper concludes by proposing a systematic framework for addressing the 'Societal Value' of products as part of an integrate sustainability assessment and allows the evaluation and comparison beyond products' shared functionality

X-ray Diagnostics of Giant Molecular Clouds in the Galactic Center Region and Past Activity of Sgr A*

Strong iron fluorescence at 6.4 keV and hard-X-ray emissions from giant molecular clouds in the Galactic center region have been interpreted as reflections of a past outburst of the Sgr A* supermassive black hole. Careful treatment of multiple interactions of photons in a complicated geometry is essential to modeling the reprocessed emissions from the dense clouds. We develop a new calculation framework of X-ray reflection from molecular clouds based on Monte Carlo simulations for accurate interpretation of high-quality observational data. By utilizing this simulation framework, we present the first calculations of morphologies and spectra of the reflected X-ray emission for several realistic models of Sgr B2, which is the most massive molecular cloud in our Galaxy. The morphology of scattered hard X-rays above 20 keV is significantly different from that of iron fluorescence due to their large penetrating power into dense regions of the cloud, probing the structure of the cloud. High-resolution spectra provide quantitative evaluation of the iron line including its Compton shoulder to constrain the mass and the chemical composition of the cloud as well as the luminosity of the illuminating source. These predictions can be checked in the near future with future X-ray missions such as NuStar (hard X-rays) and ASTRO-H (both iron lines and hard X-rays).Comment: 28 pages, 15 figures, accepted for publications in Ap

Multiplexed broadband beam steering system utilizing high speed MEMS mirrors

We present a beam steering system based on micro-electromechanical systems technology that features high speed steering of multiple laser beams over a broad wavelength range. By utilizing high speed micromirrors with a broadband metallic coating, our system has the flexibility to simultaneously incorporate a wide range of wavelengths and multiple beams. We demonstrate reconfiguration of two independent beams at different wavelengths (780 and 635 nm) across a common 5x5 array with 4 us settling time. Full simulation of the optical system provides insights on the scalability of the system. Such a system can provide a versatile tool for applications where fast laser multiplexing is necessary.Comment: 11 pages, 6 figures, submitte