On choosing a reference redox system for electrochemical measurements: A cautionary tale

The potential of a quasi-reference electrode can be determined by introducing an internal reference redox system (IRRS) which comprises either the oxidizable or reducible form of a reversible (and, ideally, outer-sphere) redox couple and then observing the cyclic voltammetric responses. The objective is to choose the IRRS so that the cyclic voltammetric response for the simultaneously present electroactive analyte system (ANS) can be observed independently of the IRRS response. We identify three fundamental paradigms describing the relative positioning of the IRRS and ANS on the potential scale, the operative redox components for the IRRS and ANS, and the starting potential (E start), reversing potential (E rev), and ending potential (E end) for the cyclic voltammetric scan as follows: paradigm A, an optimal paradigm which can produce completely independent cyclic voltammetric responses for the IRRS or for ANS; paradigm B, a less-than-optimal paradigm which can produce an independent cyclic voltammetry (CV) response for the ANS or a mixed response for the IRRS with that response on top of the ANS response; paradigm C, a problematic paradigm that can produce an independent CV response for the IRRS or a mixed response for the ANS with that response on top of the IRRS response; and any mixed response produces a thermodynamically favored redox cross-reaction which couples the IRRS and ANS systems and which can complicate the analysis of the ANS and IRRS responses. The conclusion is that paradigm C is to be avoided.

Ionic liquid effects on the redox potential of ferrocene

The ionic liquid, IL, dependence of the mid-point potential of the ferrocene|ferrocenium, Fc^0/+, couple versus the decamethylferrocene|decamethylferrocenium, DmFc^0/+, couple was studied in eleven ILs and in dichloromethane with added IL as the supporting electrolyte. The difference in mid-point potential between Fc and DmFc indicates that Fc^0/+ couple is clearly dependent on the IL structure. A variation of about 0.100 V over the range of ILs studied under neat conditions and by ca. 0.050 V when studied in dichloromethane is reported. Meanwhile, a variable potential shift ranging from 0.014 to 0.082 V was observed when data was compared in these two systems (ILs vs. dichloromethane). The effect of water and lithium ion on the Fc^0/+ and DmFc^0/+ redox potential was also evaluated and found to be minimal.

Paintings 2002

This exhibition followed an artist in residency at Marsden College, Wellington. During this residency, she engaged in a project of creating paintings from memories and imagination rather than plein-air or other reference material. The paintings and drawings became layered images from different sources culminating in essence images about her identity and experience with the Place that is Wellington.

X-ray diffraction line broadening from gold and platinum thin films

X-ray diffraction line profile analysis has been used to study the microstructure of (Ill) oriented gold and platinum thin films deposited by thermal evaporation and DC magnetron sputtering. In addition to crystallite size broadening, the profiles from these films displayed broadening arising from dislocations. A parallel investigation, using transmission electron microscopy (TEM) was undertaken to study the nature of dislocations formed, and to provide information on the dimensions of the crystallite columns in the films. X-ray data were collected at room temperature to determine the anisotropy of the broadening with (hkl), using a Siemens D5000 powder diffractometer (CuKa radiation) and two high-resolution synchrotron instruments (BM 16 at the ESRF [A=0.35A] and station 2.3 at the Daresbury laboratory. Two approaches to instrument deconvolution were investigated; Fourier deconvolution and fundamental parameters profile fitting, using Lab6 as a reference material to determine the instrument profile function. After removal of the crystallite size broadening contribution from the measured integral breadths, the residual microstrain broadening was modelled assuming dislocations based on a FCC a/2<110>{ Ill} slip system. The results of the X-ray analysis agreed with dark field TEM micrographs, which showed that many of the crystallites contained dislocations of mixed character (screw- edge).

Characterization of decamethylferrocene and ferrocene in ionic liquids : Argon and vacuum effect on their electrochemical propertiesce

The electrochemistry of decamethylferrocene (DmFc) has been studied in organic solvent systems and proven to be a superior internal reference redox standard to ferrocene (Fc). However, the electrochemical information on this redox couple in ionic liquids is still limited. Therefore, the voltammetric and amperometric behaviour of DmFc was investigated under argon and vacuum conditions in six different ionic liquids and compared to that of Fc under the same experimental conditions. Consequently, the concentration, the heterogeneous electron-transfer rate constant (k0), volatility, and diffusion coefficients (D) of Fc and Fc+, as well as the solubility, k 0, and D values for DmFc and DmFc+ were determined under argon and vacuum conditions by fitting the experimental chronoamperometric and voltammetric data with numerical and digital simulations. The rate of mass transport of ferrocene and decamethylferrocene was observed to decreases between 6-37% by changing the working atmosphere from argon to vacuum. The D Fc/DFc+ ratios are in the range 1.31-2.01 in the different ILs. Importantly, the DDmFc/DDmFc+ ratio is ≈ 1 in 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)amide, 1-methyl-1-butylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, and 1-methyl-3-ethylimidazolium tris(pentafluoroethyl)trifluorophosphate. The experimental mid-point potential and half-wave potential of Fc0/+ vs. DmFc0/+, as well as the formal potential obtained after correction for inequality in the respective diffusion coefficients of both redox processes are presented. Even though DmFc is not freely soluble in the different ILs, the results presented in this work suggest that the DmFc0/+ redox process is less dependent than Fc on the IL nature. This is a very relevant finding for the application of this transition-metal sandwich complex as an internal reference redox system in IL solutions. © 2014 Elsevier Ltd.

Investigation of effective material properties in composites with internal defect or reinforcement particles

This paper is concerned with the investigation of the effective material properties of internally defective or particle-reinforced composites. An analysis was carried out with a novel method using the two-dimensional special finite element method mixing the concept of equivalent homogeneous materials. A formulation has been developed for a series of special finite elements containing an internal defect or reinforcement in order to assure the high accuracy especially in the vicinity of defects or reinforcements. The adoption of the special finite element can greatly simplify numerical modeling of particle-composites. The numerical result provides the effective material properties of particle-reinforced composite and explains that the size of particles has great influence on the material properties. Numerical examples also demonstrate the validity and versatility of the proposed method by comparing with existing results from literatures.

Internal structure and paleoecology of the lower Permian Uzunbulak reef complex of the Tarim Basin, Northwest China

The internal construction and biotic communities of the Uzunbulak reef of the northwestern Tarim Basin are studied for the first time. The reef was built during the Sakmarian, while the reef substrate and capping beds are of latest Asselian and earliest Artinskian ages, respectively. The reef substrate beds are composed of skeletal and oncoid grainstone. Those fusulinid-dominated skeletal shoals and oncoid banks indicate a high-energy environment and produced local topographic highs on which the reef grew. Reef framework consists mainly of calcisponge bafflestone, calcisponge-Thartharella framestone, and Tubiphytes, Archaeolithoporella and Girvanella boundstones. Calcisponges were the primary frameconstructors that baffled high-energy currents. Archaeolithoporella, Tubiphytes, Girvanella and possibly microbes acted as the primary binders for the boundstone framework. Fusulinids and brachiopods were common reef dwellers. The interreef facies sediments are composed of skeletal-crinoid wackestone-packstone. Most of bioclasts have thick, micritized envelopes. The back-reef facies deposits consist of alternating skeletal packstone to wackestone and black shale. Sea-level fluctuations were probably accountable for the reef growth and demise.

Of the reefal dwellers, brachiopods are extraordinarily abundant in Uzunbulak. They are assignable to five distinctive associations, one each from the reef substrate, framework and inter-reef facies, respectively, and two from the reef capping facies. The brachiopods in the substrate beds were mostly attached to hard substrates by a pedicle, while a few species rested on soft substrates by support of halteroid spines. Cementation of the ventral valve on hard substrates characterizes attachment of the reef framework brachiopods. All inter-reef species were anchored into the substratum comprising hard material by a strong pedicle. Back-reef brachiopods dominantly rested on the soft substrates by support of halteroid spines. the framework brachiopods had the strongest wave-resistant capability;those from both substrate and inter-reef facies were moderately capable of withstanding agitation; and the backreef species preferred to live in calmwater, organic-rich muddy environments.

Importance of the contribution of Australians to the penetration of China by the China Inland Mission in the period 1888-1953, with particular reference to the work of Australian women missionaries

Australians, in the main, are unaware of the role which Australia played in the evangelization of China in the late nineteenth and the first half of the twentieth century. Most would never have heard of the China Inland Mission (CIM), the largest of the Protestant bodies which penetrated the Middle Kingdom, and few would know of the contribution that its Australian contingent, which consistently comprised about a tenth of the CIM's numbers, made towards the Christianization of that vast country. This thesis aims to raise the level of awareness in this area. Academic researchers have not totally neglected to examine the proselytization of China, and historians of the stature of Latourette have not let it escape their attention. However, most of the studies which have not merely fleetingly focused on the subject while viewing a larger canvas, have been North American, singling out the efforts of United States and Canadian bodies in introducing Christianity to the Chinese. Here, authors like Amerding, Bacon, Creighton, Gates, Hawkes, Ho, Ko, Mensendiek, Michell and Quale have left their mark. In the case of the present thesis, the outlook from which events played out in China are viewed is firmly based in Australia rather than North America. Earlier Australian research has been scarce, and is dominated by Loane and Dixon. Loane, evidently primarily working from Australasian Council minutes, mainly concentrates on the efforts of the CIM's Home Council, examining its endeavours decade by decade against a backdrop of contemporaneous events in China, and briefly referring to aspects of the lives of a cross-section of Australasian missionaries, without providing much idea about what they actually did in the field or what they achieved there. Because of its preoccupation with the Home Council, which never admitted women into its ranks, Loane's treatise is systemically biased towards men, though the more prominent of the women, like Mary Reed and Susie Garland, are given due recognition. The current thesis looks in detail at what Australians did in the field, the level of success they achieved, and at the particular contribution of Australian women towards the evangelization of China. Dixon took upon herself the formidable task of examining the endeavours of all missions in China which contained Australian missionaries. Because of the magnitude of her task, she could not focus to any great extent on particular missions, nor pursue in any detail the work of individual Australian missionaries. Like Loane, she was unable to explore what they actually did in the field or what they achieved there. Neither could she delve to any depth into the work of Australian women missionaries, though on the basis of the information she had accumulated, she drew the conclusion that Australian women had largely only brought about some unintended feminist consequences amongst Chinese women. This sweeping generalization failed to take into account the other very real social changes for Chinese women the Australian female missionaries quite purposely helped to bring about, and this thesis makes good that omission. This thesis studies aspects of the Australian missionary endeavour which both Loane and Dixon have neglected, thereby breaking new ground, and sets out to correct erroneous impressions which Dixon's dissertation has left on the historical record. One of these impressions concerned the longevity of the effect of the Australian effort in China. She had the View, writing in 1978, that the Chinese Church was moribund (a view shared by Varg and Lacy) , and that therefore the effects attributable to the endeavours of any nationality had proved fruitless, whereas the author is able to show, using modern-day sources, that the church has burgeoned in recent years thanks to earlier missionary endeavours and later neo-evangelistic efforts like Gospel radio, and now has a complement of perhaps 50 million adherents, making it second only to the United States in the size of its Protestant evangelical population. Another impression she left was that the Australian input into the evangelization of China can be largely dismissed because no totally Australian organization emerged, leaving the direction of Australia's effort in other hands. Contrary to that impression, the author shows that the Australian impact in China was significant and that Australians enjoyed more power than Dixon ever imagined. The author also shows that Australians were accepted as the equal of other nationalities in the CIM once they had acquired the necessary field expertise, a factor which doubtless also applied in respect of other missions with Australian components in China. Marchant has suggested that it is a fiction perpetuated by mission periodicals that Christianity spread and progressed in a determined manner in China. This thesis establishes that within the CIM's bailiwick, though there was some patchiness, Christianity progressed steadily and inexorably. One mission alone, the CIM, is concentrated upon, firstly in order to render the data manageable, secondly because it was the largest mission in China and had a sizeable Australian (including female) contingent, and thirdly because it exemplified many of the problems which would have been faced by missions in that country and their Australian components. The methodology employed is multifaceted. The written testimony of the missionaries themselves, contained in CIM periodicals, Field Bulletins, Monthly Notes, Annual Reports, autobiographies, personal files, diaries and letters is used to illustrate various aspects of the CIM's work in which Australians were engaged. This approach is augmented by other sources such as China and Australasian Home Council Minutes, missionary conference reports, Candidates' Books, biographies, and other selected material from archival holdings in Australia, Singapore, the United Kingdom, America and Canada. Statistics, especially ratio analyses and growth rate comparisons are used to demonstrate the relative success of different missions, missionaries and genders. Also employed are reminiscences of missionaries and descendants obtained by personal interview, and these are aggregated to provide some general conclusions. Data from these various sources have been synthesized to serve the central objective of demonstrating the importance of the contribution of Australians to the penetration of China by the CIM in the period 1888-1953 with particular reference to the work of Australian women missionaries.

Evaluation of effective material properties of composite materials using special FEM

In the present paper, a novel method using the special 2D finite element method (FEM) and the concept of equivalent homogeneous materials has been employed to evaluate the effective material properties of composites. Special 2D finite elements containing an internal defect or reinforcement have been well developed in order to greatly simplify the numerical modeling of composites. It can assure the high precision especially in the vicinity of defects or reinforcements in composite materials. Some numerical examples will be provided to demonstrate the validity and versatility of the proposed method by comparing the existing results from other literatures.

Tailoring enzymes for biofuel production with reference to Australian biomass

Manufacture of biofuels from existing biomass may provide a sustainable alternative to the extensive utilization of fossil fuels. Biomass offers environmental advantage over fossil fuels as it is a renewable energy source with low sulphur and nitrogen content and is carbon neutral over its production and utilization. Ranges of biomass are reported worldwide to be suitable raw material for bioethanol production. These can be generally classified into three groups; sucrose based (sugar cane), starch based (corn, wheat and barley) and lignocellulosic (which is mostly comprised of lignin, cellulose and hemicelluloses in grasses, wood and straw) materials. However, the limited supply of two biomass groups (sucrose and starch) will not satisfy society’s growing energy demands; thus biofuel technology based on lignocelluloses is under intense investigation. The main bottleneck in lignocellulosic biomass conversion for biofuel production is the enzymatic depolymerisation of cell wall polysaccharides into fermentable sugars. Protein engineering has recently been used to improve the performance of lignocelluloses degrading enzymes, as well as proteins involved in biofuel synthesis pathways. We have produced a recombinant enzyme that has the ability to produce monomeric sugars from a complex substrate. This presentation will summarize current efforts to develop an enzymatic treatment which would facilitate the economical processing of biomass available in Australia for bioenergy generation.