The Effect of Synthesis Pressure on Properties of Eu-Doped ZnO Nanopowders Prepared by Microwave Hydrothermal Method

In the current research, europium doped ZnO nanopowders prepared by a microwave hydrothermal method are investigated. The effects of synthesis pressure on the morphologies, crystal structures, and optical properties of Eu-doped ZnO were analyzed by scanning electron microscopy, X-ray diffraction, cathodo- and photoluminescence. From our investigations it can be concluded that the synthesis pressure strongly influences the surface morphology. With the increase of the synthesis pressure from 2 MPa to 10 MPa significant changes can be observed. An increase of the mean crystallites sizes and change of the intensity ratio between the near band edge and defect related deep level emission band of ZnO were observed

Solution heat treatment of aluminium 7075 by induction heating

Niniejszy artykuł dotyczy badań przesycania stopu aluminium 7075 metodą indukcyjną. Badania prowadzono w specjalnie zaprojektowanej komorze wypełnionej argonem. W pierwszej kolejności zbadano wpływ mocy i czasu na głębokość przesycania warstwy wierzchniej. Następnie przeprowadzono zgniot i próbki poddano starzeniu. Zbadano gradient twardości warstwy wierzchniej oraz przeanalizowano morfologie próbek.The major objective of this study is to solid solution treatment of 7075 aluminium alloy by induction heating. This study was carried out in an argonium atmosphere chamber. The first step was to analyze the influence of generator power and time on the thickness of solid solution layer. The second step involved cold work of the sample and artificial ageing treatment. Additionally, the morphology and hardness profile was measured

High Pressure Synthesis versus Calcination – Different Approaches to Crystallization of Zirconium Dioxide

Calcination and microwave-assisted hydrothermal processing of precipitated zirconium dioxide are compared. Characterization of synthesized products of these two technologies is presented. The infiuence of thermal treatment up to 1200oC on the structural and spectroscopic properties of the so-obtained zirconium dioxide is examined. It was found that initial crystallization of material inhibits the crystal growth up to the 800oC (by means of XRD and TEM techniques), while the material crystallized from amorphous hydroxide precursor at 400oC, exhibits 26 nm sized crystallites already. It was found using the TG technique that the temperature range 100–200oC during the calcination process is equivalent to a microwave hydrothermal process by means of water content. Mass loss is estimated to be about 18%. Based on X-ray investigations it was found that the initial hydroxide precursor is amorphous, however, its luminescence activity suggests the close range ordering in a material

Magnetic study of Fe2O3/ZnO nanocomposites

Fine particles of Fe2O3/ZnO were synthesized by wet chemical method. The morphological and structural properties of the mixed system were investigated by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The major phase was determined to be the cubic spinel phase of γ-Fe2O3 maghemite with mean crystalline size of about 20 nm together with small amounts of hexagonal ZnO and ZnFe2O4. The magnetic properties of the material were investigated by ferromagnetic resonance (FMR) in the temperature range from liquid helium to room temperature. An asymmetric and very intense FMR signal was recorded exhibiting strong shift to low magnetic fields with decrease in temperature. Analysis of the FMR spectra in terms of two separate line components indicates the presence of strongly anisotropic interactions. © 2010 Elsevier B.V. All rights reserved

Stakeholder engagement and asset management: a case study of the Gold Coast airport, Queensland

One of the fastest growing industries – aviation – faces serious and compounding challenges in maintaining healthy relationships with community stakeholders. One area in aviation creating community conflict is noise pollution. However, current understandings of the factors that affect noise annoyance of the community are poorly conceptualized. More importantly, the way community needs and expectations could be incorporated in airport governance has been inadequately framed to address the issue of aircraft noise. This paper proposes the util-ity of adopting an integrated strategic asset management (ISAM) framework [1] to explore the dynamic nature of relationships between and airport and its surrounding area. The case of the Gold Coast Airport (OOL) operator and community stakeholders is used. This paper begins with an overview of the ISAM framework in the context of airport governance and sustainable development – as a way to find a balance between economic opportunities and societal concerns through stakeholder engagement. Next, an exploratory case study is adopted as a method to explore the noise-related complaints, complainants, and possible causes. Fol-lowing this, the paper reviews three approaches to community stakeholder engagement in Australia, Japan, and UK and discusses their implications in the con-text of OOL. The paper concludes with a contention that airport governance is likely to be much more effective with the adoption of ISAM framework than without it