135 resultados para SUPPORTED COBALT CATALYSTS


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Synthesis of imines from amines and aliphatic alcohols (C1–C6) in the presence of base on supported palladium nanoparticles has been achieved for the first time. The catalytic system shows high activity and selectivity in open air at room temperature. As an example of the isostructural Ln3Sb3Co2O14 (Ln: La, Pr, Nd, Sm—Ho) series with an ordered pyrochlore structure, the La variant is prepared by a citrate complex method employing stoichiometric amounts of La(NO3)3, Co(NO3)2, and Sb tartrate together with citric acid with a metal/citrate molar ratio of 1:2

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Isolated and purified organosolv eucalyptus wood lignin was depolymerized at different temperatures with and without mesostructured silica catalysts (i.e., SBA-15, MCM-41, ZrO2-SBA-15 and ZrO2-MCM-41). It was found that at 300 oC for 1 h with a solid/liquid ratio of 0.0175/1 (w/v), the SBA-15 catalyst with high acidity gave the highest syringol yield of 23.0% in a methanol/water mixture (50/50, wt/wt). Doping with ZrO2 over these catalysts did not increase syringol yield, but increased the total amount of solid residue. Gas chromatography-mass spectrometry (GC-MS) also identified other main phenolic compounds such as 1-(4-hydroxy-3,5-dimethoxyphenyl)-ethanone, 1,2-benzenediol, and 4-hydroxy-3,5-dimethoxy-benzaldehyde. Analysis of the lignin residues with Fourier transform-Infrared spectroscopy (FT-IR) indicated decreases in the absorption bands intensities of OH group, C-O stretching of syringyl ring and aromatic C-H deformation of syringol unit, and an increase in band intensities associated with the guaiacyl ring, confirming the type of products formed.

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This paper presents a feasibility study on structural damage alarming and localization of long-span cable-supported bridges using multi-novelty indices formulated by monitoring-derived modal parameters. The proposed method which requires neither structural model nor damage model is applicable to structures of arbitrary complexity. With the intention to enhance the tolerance to measurement noise/uncertainty and the sensitivity to structural damage, an improved novelty index is formulated in terms of auto-associative neural networks (ANNs) where the output vector is designated to differ from the input vector while the training of the ANNs needs only the measured modal properties of the intact structure under in-service conditions. After validating the enhanced capability of the improved novelty index for structural damage alarming over the commonly configured novelty index, the performance of the improved novelty index for damage occurrence detection of large-scale bridges is examined through numerical simulation studies of the suspension Tsing Ma Bridge (TMB) and the cable-stayed Ting Kau Bridge (TKB) incurred with different types of structural damage. Then the improved novelty index is extended to formulate multi-novelty indices in terms of the measured modal frequencies and incomplete modeshape components for damage region identification. The capability of the formulated multi-novelty indices for damage region identification is also examined through numerical simulations of the TMB and TKB.

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Science, Art and Science Art collaborations are generally presented and understood in terms of their products. We argue that the process of Science art can be a significant, even principal benefit of these collaborations, even though it may be largely invisible to anyone other than the collaborators. Hosting the Centenary of Canberra Science Art Commission at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has shown us that while Science and Art pursue orthogonal dimensions of creativity and innovation, collaborators can combine these directions to access new areas of imagination and ideas.

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Osteoblast lineage cells are direct effectors of osteogenesis and are, therefore, commonly used to evaluate the in vitro osteogenic capacity of bone substitute materials. This method has served its purposes when testing novel bone biomaterials; however, inconsistent results between in vitro and in vivo studies suggest the mechanisms that govern a material's capacity to mediate osteogenesis are not well understood. The emerging field of osteoimmunology and immunomodulation has informed a paradigm shift in our view of bone biomaterials–from one of an inert to an osteoimmunomodulatory material–highlighting the importance of immune cells in materials-mediated osteogenesis. Neglecting the importance of the immune response during this process is a major shortcoming of the current evaluation protocol. In this study we evaluated a potential angiogenic bone substitute material cobalt incorporated with β-tricalcium phosphate (CCP), comparing the traditional “one cell type” approach with a “multiple cell types” approach to assess osteogenesis, the latter including the use of immune cells. We found that CCP extract by itself was sufficient to enhance osteogenic differentiation of bone marrow stem cells (BMSCs), whereas this effect was cancelled out when macrophages were involved. In response to CCP, the macrophage phenotype switched to the M1 extreme, releasing pro-inflammatory cytokines and bone catabolic factors. When the CCP materials were implanted into a rat femur condyle defect model, there was a significant increase of inflammatory markers and bone destruction, coupled with fibrous encapsulation rather than new bone formation. These findings demonstrated that the inclusion of immune cells (macrophages) in the in vitro assessment matched the in vivo tissue response, and that this method provides a more accurate indication of the essential role of immune cells when assessing materials-stimulated osteogenesis in vitro.

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I must admit that I approached the European Union-supported educational research 1995-2003: Briefing papers for policy makers with a sense of trepidation. As a researcher who defines himself as socially critical, I wondered about the dynamics of a policy document that was published by the bureaucracy that has, in some form, a vested interest in the structure and operation of education in its various guises. In turning my attention to this review, I decided to focus my attention on the third guiding question that argues education and training "are strongly interconnected with concerns that include citizenship and democratic participation, inequalities and social justice, cultural diversity and quality of life" (Millei, 2005). The Briefing Papers include recommendations on democracy and citizenship, social exclusion and equality, gender and dealing with mental illness in schools...

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This work reports the effect of seed nanoparticle size and concentration effects on heterogeneous crystal nucleation and growth in colloidal suspensions. We examined these effects in the Au nanoparticle-seeded growth of Au-ZnO hetero-nanocrystals under synthesis conditions that generate hexagonal, cone-shaped ZnO nanocrystals. It was observed that small (~ 4 nm) Au seed nanoparticles form one-to-one Au-ZnO hetero dimers and that Au nanoparticle seeds of this size can also act as crystallization ‘catalysts’ that readily promote the nucleation and growth of ZnO nanocrystals. Larger seed nanoparticles (~9 nm, ~ 11 nm) provided multiple, stable ZnO-nucleation sites, generating multi-crystalline hetero trimers, tetramers and oligomers.

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This work aims to understand the influence of TiO2 surface structure in Au/TiO2 catalysts on CO oxidation. Au nanoparticles (3 wt%) in the range of 4 to 8 nm were loaded onto four kinds of TiO2 surfaces, which had different surface structures and were synthesized by calcining hydrogen titanate nanotubes at various temperatures and in different atmospheres. The Au catalyst supported on anatase nanorods exhibited the highest activity in CO oxidation at 30 °C among all the five Au/TiO2 catalysts including the reference catalyst of Au/TiO2-P25. X-ray photoelectron spectroscopy (XPS) and infrared emission spectra (IES) results indicate that the anatase nanorods have the most active surface on which water molecules can be strongly adsorbed and OH groups can be formed readily. Theoretical calculation indicates that the surface OH can facilitate the O2 adsorption on the anatase surface. Such active surface features are conducive to the O2 activation and CO oxidation

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Supported nanoparticles (NPs) of nonplasmonic transition metals (Pd, Pt, Rh, and Ir) are widely used as thermally activated catalysts for the synthesis of important organic compounds, but little is known about their photocatalytic capabilities. We discovered that irradiation with light can significantly enhance the intrinsic catalytic performance of these metal NPs at ambient temperatures for several types of reactions. These metal NPs strongly absorb the light mainly through interband electronic transitions. The excited electrons interact with the reactant molecules on the particles to accelerate these reactions. The rate of the catalyzed reaction depends on the concentration and energy of the excited electrons, which can be increased by increasing the light intensity or by reducing the irradiation wavelength. The metal NPs can also effectively couple thermal and light energy sources to more efficiently drive chemical transformations.

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Overview This review of research conducted with supported playgroups was prepared for the Queensland Department of Education, Training and Employment (DETE). The report provides a synthesis of the research on the effectiveness of supported playgroups to improve child, parent, and community outcomes and to identify key features of supported playgroups that support effective outcomes. Supported playgroups are community-based services that provide a low intensity parenting intervention, through regular group sessions for parent-child dyads. Supported playgroups target vulnerable families who may benefit from parenting support. Supported playgroups have common goals to enhance children’s early learning and parental wellbeing. Method A search strategy was devised to identify research studies, nationally and internationally, that involved parent-child group programs for families with young children, delivered under the leadership of an employed facilitator. Academic databases and other data sources were explored for studies conducted in the period from 2004 to 2014. Summary descriptions of the research studies were developed; assessment of research methodologies was made; research evidence on the effectiveness of supported playgroups to improve child, parent, and community outcomes was identified; and comparative analyses of the implementation features of supported playgroups were completed. Findings The search strategy identified 34 research publications, reporting on 29 different programs. Twenty-six of the studies report on research conducted in Australia and eight reported on research conducted in other countries, including the United Kingdom, Canada, and the United States. Three clusters of playgroups were identified: Category 1 - Standard supported playgroups; Category 2 - Mobile playgroups; Category 3 – Supported playgroups with specific interventions. The research studies identified encompassed experimental and non-experimental research designs. The studies of standard supported playgroups and mobile playgroups were most often qualitative studies and modest in scale, in terms of the number of research participants. Experimental and quasi-experimental research designs characterised the studies identified in the category of supported playgroups with specific interventions. Overall, the research studies that were categorised as supported playgroups with specific interventions provided stronger evidence for effectiveness to improve parental behaviour in ways that are known to support children’s early developmental competence. Qualitative studies, including case studies and ethnographic research, documented important features of program delivery, such as the importance of facilitators’ interpersonal skills to positive experiences for families in the playgroups; as well as the important opportunities that the playgroups afforded to vulnerable families to reduce social isolation. Conclusions The potential for supported playgroups to improve a broad range of learning and psychosocial outcomes for children and parents was suggested by many of the research studies. However, the nature of the research designs employed means that it is not possible to conclude that there is strong evidence of the impact of supported playgroups on child, parent, and community outcomes. The qualitative studies did provide rich descriptions about the implementation processes of playgroups and also captured the variability in the delivery of the playgroups in terms of who participated, local contextual factors that impacted on the playgroup experiences, and the nature of the experiences of parents within the playgroups. Research methodologies need to be employed that address the limitations of the studies to date. This would provide more defensible evidence that supported playgroups have an impact over time on outcomes for children, families, and communities. Overall, this area of research remains relatively under-evaluated in terms of rigorous research designs. The identified research studies point to some promising research directions but do not yet enable strong claims to be made about the effectiveness of the standard playgroup or mobile playgroup models to impact on parenting outcomes. Data collected from interview and survey methodologies clearly identifies that supported playgroups are highly acceptable to families. Given the popularity of supported playgroups to engage families across diverse communities, and the reported high levels of satisfaction and benefits identified within many of the research studies, it is clear that the provision of supported playgroups is fulfilling an important community need by providing support to parents with young children. However, there is a need to strengthen the evidence base that supported playgroups are an effective early parenting intervention that improves outcomes for children, parents, and communities.

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Plasmonics is a recently emerged technology that enables the compression of electromagnetic waves into miniscule metallic structures, thus enabling the focusing and routing of light on the nanoscale. Plasmonic waveguides can be used to miniaturise the size of integrated chip circuits while increasing the data transmission speed. Plasmonic waveguides are used to route the plasmons around a circuit and are a major focus of this thesis. Also, plasmons are highly sensitive to the surrounding dielectric environment. Using this property we have experimentally realised a refractive index sensor to detect refractive index change in solutions.

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A stable Y-doped BaZrO3 electrolyte film, which showed a good performance in proton-conducting SOFCs, was successfully fabricated using a novel ionic diffusion strategy.

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The difficult sintering of BaZr0.8Y0.2O 3-δ (BZY20) powders makes the fabrication of anode-supported BZY20 electrolyte films complex. Dense BZY20 membranes were successfully fabricated on anode substrates made of sinteractive NiO-BZY20 powders, prepared by a combustion method. With respect to traditional anode substrates made of powders prepared by mechanical mixing, the anode substrates made of the wet-chemically synthesized composite NiO-BZY20 powders significantly promoted the densification of BZY20 membranes: dense BZY20 films were obtained after co-pressing and co-firing at 1300 °C, a much lower temperature than those usually needed for densifying BZY20 membranes. Improved electrochemical performance was also observed: the supported BZY20 films maintained a high proton conductivity, up to 5.4 × 10-3 S cm-1 at 700 °C. Moreover, an anode-supported fuel cell with a 30 m thick BZY20 electrolyte film fabricated at 1400 °C on the anode made of the wet-chemically synthesized NiO-BZY20 powder showed a peak power density of 172 mW cm-2 at 700 °C, using La0.6Sr0.4Co 0.2Fe0.8O3-δ-BaZr0.7Y 0.2Pr0.1O3-δ as the cathode material, with a remarkable performance for proton-conducting solid oxide fuel cell (SOFC) applications.