Curtin University

About: Curtin University is a education organization based out in Perth, Western Australia, Australia. It is known for research contribution in the topics: Population & Zircon. The organization has 14257 authors who have published 48997 publications receiving 1336531 citations. The organization is also known as: WAIT & Western Australian Institute of Technology.

Recent advances and prospective in ruthenium-based materials for electrochemical water splitting

Abstract: As a highly appealing technology for hydrogen generation, water electrolysis including oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode largely depends on the availability of efficient electrocatalysts. Accordingly, over the past years, much effort has been made to develop various electrocatalysts with superior performance and reduced cost. Among them, ruthenium (Ru)-based materials for OER and HER are very promising because of their prominent catalytic activity, pH-universal application, the cheapest price among the precious metal family, and so on. Herein, recent advances in this hot research field are comprehensively reviewed. A general description about water splitting is presented to understand the reaction mechanism and proposed scaling relations toward activities, and key stability issues for Ru-based materials are further given. Subsequently, various Ru-involving electrocatalysts are introduced and classified into different groups for improving or optimizing electrocatalytic properties, with a special focus on several significant bifunctional electrocatalysts along with a simulated water electrolyzer. Finally, a perspective on the existing challenges and future progress of Ru-based catalysts toward OER and HER is provided. The main aim here is to shed some light on the design and construction of emerging catalysts for energy storage and conversion technologies.

Activated carbon supported cobalt catalysts for advanced oxidation of organic contaminants in aqueous solution

Abstract: A heterogeneous cobalt catalyst was prepared by impregnation of cobalt ion on an activated carbon (AC) and used to activate peroxymonosulphate (PMS) for advanced oxidation of phenol in aqueous solution. The Co/AC catalyst was characterised by several techniques such as XRD, EDS, SEM, and TGA. It was found that Co2O3 was the major form of Co species and was homogeneously distributed on the activated carbon surface. Co/AC exhibited high activity in oxidation of phenol with sulphate radicals and 100% decomposition and 80% TOC removal could be achieved in 60 min at the conditions of 500 ml phenol solution of 25 ppm, 0.1 g catalyst and 1 g peroxymonosulphate. The catalyst also exhibited stable performance after several rounds of regeneration. Several operational parameters such as catalyst and oxidant amount, temperature on the rate of oxidation were found to influence the phenol oxidation.

Ti-in-zircon thermometry: applications and limitations

Abstract: The titanium concentrations of 484 zircons with U-Pb ages of ∼1 Ma to 4.4 Ga were measured by ion microprobe. Samples come from 45 different igneous rocks (365 zircons), as well as zircon megacrysts (84) from kimberlite, Early Archean detrital zircons (32), and zircon reference materials (3). Samples were chosen to represent a large range of igneous rock compositions. Most of the zircons contain less than 20 ppm Ti. Apparent temperatures for zircon crystallization were calculated using the Ti-in-zircon thermometer (Watson et al. 2006, Contrib Mineral Petrol 151:413–433) without making corrections for reduced oxide activities (e.g., TiO2 or SiO2), or variable pressure. Average apparent Ti-in-zircon temperatures range from 500° to 850°C, and are lower than either zircon saturation temperatures (for granitic rocks) or predicted crystallization temperatures of evolved melts (∼15% melt residue for mafic rocks). Temperatures average: 653 ± 124°C (2 standard deviations, 60 zircons) for felsic to intermediate igneous rocks, 758 ± 111°C (261 zircons) for mafic rocks, and 758 ± 98°C (84 zircons) for mantle megacrysts from kimberlite. Individually, the effects of reduced \( a_{{\rm TiO}_{2}}\) or \( a_{{\rm SiO}_{2}}\), variable pressure, deviations from Henry’s Law, and subsolidus Ti exchange are insufficient to explain the seemingly low temperatures for zircon crystallization in igneous rocks. MELTs calculations show that mafic magmas can evolve to hydrous melts with significantly lower crystallization temperature for the last 10–15% melt residue than that of the main rock. While some magmatic zircons surely form in such late hydrous melts, low apparent temperatures are found in zircons that are included within phenocrysts or glass showing that those zircons are not from evolved residue melts. Intracrystalline variability in Ti concentration, in excess of analytical precision, is observed for nearly all zircons that were analyzed more than once. However, there is no systematic change in Ti content from core to rim, or correlation with zoning, age, U content, Th/U ratio, or concordance in U-Pb age. Thus, it is likely that other variables, in addition to temperature and \( a_{{\rm TiO}_{2}}\), are important in controlling the Ti content of zircon. The Ti contents of igneous zircons from different rock types worldwide overlap significantly. However, on a more restricted regional scale, apparent Ti-in-zircon temperatures correlate with whole-rock SiO2 and HfO2 for plutonic rocks of the Sierra Nevada batholith, averaging 750°C at 50 wt.% SiO2 and 600°C at 75 wt.%. Among felsic plutons in the Sierra, peraluminous granites average 610 ± 88°C, while metaluminous rocks average 694 ± 94°C. Detrital zircons from the Jack Hills, Western Australia with ages from 4.4 to 4.0 Ga have apparent temperatures of 717 ± 108°C, which are intermediate between values for felsic rocks and those for mafic rocks. Although some mafic zircons have higher Ti content, values for Early Archean detrital zircons from a proposed granitic provenance are similar to zircons from many mafic rocks, including anorthosites from the Adirondack Mts (709 ± 76°C). Furthermore, the Jack Hills zircon apparent Ti-temperatures are significantly higher than measured values for peraluminous granites (610 ± 88°C). Thus the Ti concentration in detrital zircons and apparent Ti-in-zircon temperatures are not sufficient to independently identify parent melt composition.

A Unified Framework for Optimizing Linear Nonregenerative Multicarrier MIMO Relay Communication Systems

Abstract: In this paper, we develop a unified framework for linear nonregenerative multicarrier multiple-input multiple-output (MIMO) relay communications in the absence of the direct source-destination link. This unified framework classifies most commonly used design objectives such as the minimal mean-square error and the maximal mutual information into two categories: Schur-concave and Schur-convex functions. We prove that for Schur-concave objective functions, the optimal source precoding matrix and relay amplifying matrix jointly diagonalize the source-relay-destination channel matrix and convert the multicarrier MIMO relay channel into parallel single-input single-output (SISO) relay channels. While for Schur-convex objectives, such joint diagonalization occurs after a specific rotation of the source precoding matrix. After the optimal structure of the source and relay matrices is determined, the linear nonregenerative relay design problem boils down to the issue of power loading among the resulting SISO relay channels. We show that this power loading problem can be efficiently solved by an alternating technique. Numerical examples demonstrate the effectiveness of the proposed framework.