Solution of a System of Generalized Abel Integral Equations Using Fractional Calculus

A method is presented for obtaining useful closed form solution of a system of generalized Abel integral equations by using the ideas of fractional integral operators and their applications. This system appears in solving certain mixed boundary value problems arising in the classical theory of elasticity.

Improved assessment of aerosol absorption using OMI-MODIS joint retrieval

The Ozone Monitoring Instrument (OMI) aboard EOS-Aura and the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard EOS-Aqua fly in formation as part of the A-train. Though OMI retrieves aerosol optical depth (AOD) and aerosol absorption, it must assume aerosol layer height. The MODIS cannot retrieve aerosol absorption, but MODIS aerosol retrieval is not sensitive to aerosol layer height and with its smaller pixel size is less affected by subpixel clouds. Here we demonstrate an approach that uses MODIS-retrieved AOD to constrain the OMI retrieval, freeing OMI from making an a priori estimate of aerosol height and allowing a more direct retrieval of aerosol absorption. To predict near-UV optical depths using MODIS data we rely on the spectral curvature of the MODIS-retrieved visible and near-IR spectral AODs. Application of an OMI-MODIS joint retrieval over the north tropical Atlantic shows good agreement between OMI and MODIS-predicted AODs in the UV, which implies that the aerosol height assumed in the OMI-standard algorithm is probably correct. In contrast, over the Arabian Sea, MODIS-predicted AOD deviated from the OMI-standard retrieval, but combined OMI-MODIS retrievals substantially improved information on aerosol layer height (on the basis of validation against airborne lidar measurements). This implies an improvement in the aerosol absorption retrieval, but lack of UV absorption measurements prevents a true validation. Our study demonstrates the potential of multisatellite analysis of A-train data to improve the accuracy of retrieved aerosol products and suggests that a combined OMI-MODIS-CALIPSO retrieval has large potential to further improve assessments of aerosol absorption.

Simple Method of Preparing Graphene Flakes by an Arc-Discharge Method

Arc discharge between graphite electrodes under a relatively high pressure of hydrogen yields graphene flakes generally containing 2-4 layers in the inner wall region of the arc chamber. The graphene flakes so obtained have been characterized by X-ray diffraction, atomic force microscopy, transmission electron microscopy, and Raman spectroscopy. The method is eminently suited to dope graphene with boron and nitrogen by carrying out arc discharge in the presence of diborane and pyridine respectively.

CMC simulations of lifted turbulent jet flame in a vitiated coflow

Lifted turbulent jet diffusion flame is simulated using Conditional Moment Closure (CMC). Specifically, the burner configuration of Cabra et al. [R. Cabra, T. Myhrvold, J.Y. Chen. R.W. Dibble, A.N. Karpetis, R.S. Barlow, Proc. Combust. Inst. 29 (2002) 1881-1887] is chosen to investigate H-2/N-2 jet flame supported by a vitiated coflow of products of lean H-2/air combustion. A 2D, axisymmetric flow-model fully coupled with the scalar fields, is employed. A detailed chemical kinetic scheme is included, and first order CIVIC is applied. Simulations are carried out for different jet velocities and coflow temperatures (T-c) The predicted liftoff generally agrees with experimental data, as well as joint-PDF results. Profiles of mean scalar fluxes in the mixture fraction space, for T-c = 1025 and 1080 K reveal that (1) Inside the flame zone, the chemical term balances the molecular diffusion term, and hence the Structure is of a diffusion flamelet for both cases. (2) In the pre-flame zone, the structure depends on the coflow temperature: for the 1025 K case, the chemical term being small, the advective term balances the axial turbulent diffusion term. However, for the 1080 K case. the chemical term is large and balances the advective term, the axial turbulent diffusion term being small. It is concluded that, lift-off is controlled (a) by turbulent premixed flame propagation for low coflow temperature while (b) by autoignition for high coflow temperature. (C) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Influence of Martensite Content and Morphology on Tensile and Impact Properties of High-Martensite Dual-Phase Steels

A series of dual-phase (DP) steels containing finely dispersed martensite with different volume fractions of martensite (V-m) were produced by intermediate quenching of a boron- and vanadium-containing microalloyed steel. The volume fraction of martensite was varied from 0.3 to 0.8 by changing the intercritical annealing temperature. The tensile and impact properties of these steels were studied and compared to those of step-quenched steels, which showed banded microstructures. The experimental results show that DP steels with finely dispersed microstructures have excellent mechanical properties, including high impact toughness values, with an optimum in properties obtained at similar to 0.55 V-m. A further increase in V-m was found to decrease the yield and tensile strengths as well as the impact properties. It was shown that models developed on the basis of a rule of mixtures are inadequate in capturing the tensile properties of DP steels with V-m > 0.55. Jaoul-Crussard analyses of the work-hardening behavior of the high-martensite volume fraction DP steels show three distinct stages of plastic deformation.

Subsurface deformation in dry sliding of hypo-eutectic Al-Si alloys

The subsurface deformation during dry sliding of Al-Si alloys is studied by fragmentation of silicon particles. The size of the fragmented particles does not vary with load. The depth of deformation is found to increase with increase in normal load. This experimental observation agrees with load-deformation depth characteristics obtained by a slip line field model.

Using lead sulphate instead of lead oxide in flux growth of yttrium iron garnet(YIG) crystals

Crystal growth of YIG from fluxes containing lead sulphate in place of lead oxide in the usual lead oxide-lead fluoride-boron oxide flux system has been tried. Lead sulphate decomposes during crystal growth giving lead oxide and sulphur trioxide. Due to the influence of sulphur trioxide in the system the yield of crystals almost doubles. There is no change either in the morphology of the crystals or their lattice parameter. It is possible that solubility of YIG is different in the new flux and the changed solubility causes the increase in yield of crystals.

“Success in (Surviving) Bioscience and Pharmacology” – an eBook to improve the retention of diploma nurses transitioning to a Bachelor of Nursing course

Diploma students transitioning into the NS40 BNursing (BN) course at QUT withdraw from the bioscience and pharmacology units, and leave the university at higher rates than traditional students. The diploma students, entering in second year, have missed out on 2 units of bioscience taught to the traditional students in their first year, and miss out on a 3rd unit of bioscience taught to the traditional students in their 2nd year. Instead the diploma students receive one specialized unit in bioscience only i.e. a bridging unit. As a consequence, the diploma students may not have the depth of bioscience knowledge to be able to successfully study the bridging unit (LSB111) or the pharmacology unit (LSB384). Our plan was to write an eBook which refreshed and reinforced diploma students’ knowledge of bioscience aiming to prepare them with the concepts and terminology, and to build a level of confidence to support their transition to the BN. We have previously developed an intervention associated with reduced attrition of diploma nursing students, and this was our starting point. The study skills part of the initial intervention was addressed in the eBook, by links to the specialist services and resources available from our liaison librarian and academic skills adviser. The introductory bioscience/pharmacology information provided by the previous intervention involved material from standard textbooks. However, we considered this material too difficult for diploma students. Thus, we created simplified diagrams to go with text as part of our eBook. The outcome is an eBook, created and made available to the diploma students via the Community Website: “Surviving Bioscience and Pharmacology”. Using simplified diagrams to illustrate the concise text, definition to explain the concepts, the focus has been on encouraging self-awareness and help-seeking strategies and building students who take responsibility for their learning. All the nursing students in the second semester LSB384 Pharmacology Unit have been surveyed face-to-face to get feedback on their engagement with the eBook resource. The data has not been analysed to date. An important consideration is that the website be evaluated by the diploma students as they come into bioscience in first semester (LSB111), the student population for whom the eBook is primarily intended. To get a good response rate we need to do a face-to-face survey. However, we have not been able to do this, as the co-ordinator of the unit has changed since we started the project, and the present co-ordinator will not allow us access to these students.

Low temperature fluorination of sulphur compounds with elemental fluorine

Low temperature fluorination technique is adopted for fluorination of the following sulphur compounds in freon-11 medium (1) Sulphur dioxide (2) Thionyl chloride (3) Sulphuryl chloride (4) Tetrasulphur tetra nitride and (5) Sulphur bromide. All the compounds undergo oxidative fluorination to give rise to sulphur-fluorine compounds except sulphuryl chloride which resists fluorination. Sulphuryl chloride thus behaves as a good solvent medium for fluorination of other reactive compounds like elemental sulphur. Details of the experimental procedures adopted and the identification of the products will be presented.

Characterization of dry sliding wear of Al---Si alloys

Controversy exists in the published literature as to the effect of silicon content and pressure on the dry sliding wear of Al---Si alloys. The present paper attempts to clarify the question by reporting a statistical analysis of data obtained from factorially designed experiments conducted on a pinon-disc machine in the pressure range 0.105–1.733 MPa and speed range 0.19–0.94 m s−1. Under these conditions it was found that, in the range 4–24 wt.% Si, wear of binary unmodified alloys does not significantly differ between the alloys. However, it is significantly less than that corresponding to an alloy containing no silicon. The effect of pressure on wear rate was found to be linear and monotonie and, over the narrow range of speeds used, the wear rate was found to be unaffected by speed. The coefficient of friction was found to be insensitive to variations in silicon content, pressure and speed.

Reactivity of Cationic Terminal Borylene Complexes: Novel Mechanisms for Insertion and Metathesis Chemistry Involving Strongly Lewis Acidic Ligand Systems

The reactions of terminal borylene complexes of the type [CpFe(CO)(2)(BNR2)](+) (R = `Pr, Cy) with heteroallenes have been investigated by quantum-chemical methods, in an attempt to explain the experimentally observed product distributions. Reaction with dicyclohexylcarbodiimide (CyNCNCy) gives a bis-insertion product, in which 1 equiv of carbodiimide is assimilated into each of the Fe=B and B=N double bonds to form a spirocyclic boronium system. In contrast, isocyanates (R'NCO, R' = Ph, 2,6-wXy1, CY; XYl = C6H3Me2) react to give isonitrile complexes of the type [CpFe(CO)(2)(CNR')]+, via a net oxygen abstraction (or formal metathesis) process. Both carbodiimide and socyanate substrates are shown to prefer initial attack at the Fe=B bond rather than the B=N bond of the borylene complex. Further mechanistic studies reveal that the carbodiimide reaction ultimately leads to the bis-insertion compounds [CpFe(CO)(2)C(NCy)(2)B(NCY)(2)CNR2](+), rather than to the isonitrile system [CpFe(CO)(2)(CNCy)](+), on the basis of both thermodynamic (product stability) and kinetic considerations (barrier heights). The mechanism of the initial carbodiimide insertion process is unusual in that it involves coordination of the substrate at the (borylene) ligand followed by migration of the metal fragment, rather than a more conventional process: i.e., coordination of the unsaturated substrate at the metal followed by ligand migration. In the case of isocyanate substrates, metathesis products are competitive with those from the insertion pathway. Direct, single-step metathesis reactivity to give products containing a coordinated isonitrile ligand (i.e. [CpFe(CO)(2)(CNR')](+)) is facile if initial coordination of the isocyanate at boron occurs via the oxygen donor (which is kinetically favored); insertion chemistry is feasible when the isocyanate attacks initially via the nitrogen atom. However, even in the latter case, further reaction of the monoinsertion product so formed with excess isocyanate offers a number of facile (low energetic barrier) routes which also generate ['CpFe(CO)(2)(CNR')](+), rather than the bis-insertion product [CpFe(CO)(2)C(NR')(O)B(NR')(O)CNR2](+) (i.e., the direct analogue of the observed products in the carbodiimide reaction).

Male nursing students in training: A comparative analysis of hidden advantage and discrimination

Aim The aim of this study was to examine the lived experience of men training to be registered nurses within a regional New Zealand context. Design This study draws upon the key principles of descriptive phenomenology. Sample Five male students enrolled from the 1st and 3rd year of the BN programme. Findings - A Career with Prospects - Gender inequality by superiors; - Developing professional boundaries with female colleagues; - Being unique has its advantages.

A new synthetic procedure for the preparation of pyridinium tetrafluoroborate and hexafluorosilicate

Pyridinium tetrafluoroborate (C5H5NHBF4) and pyridinium hexafluorosilicate [(C5H5NH)2SiF6] have been prepared in good yields and high purity by the reaction of pyridinium poly(hydrogen fluoride) with oxides and acids of boron and silicon respectively. The salts have been characterised by melting points, IR, 1H and 19F NMR spectroscopy and chemical analysis.

Between-tree variation in fruit quality and fruit mineral concentrations of Hass avocados

Inconsistent internal fruit quality in Hass avocados affects consumer confidence. To determine the influence of individual trees on fruit quality, Hass avocado fruit were harvested from adjacent trees of similar external appearance in 3 commercial orchards in 1998 and 1 orchard in 1999. The trees in each orchard were grown with similar commercial practices and in similar soil types. Within each location, there were significant (P<0.05) differences in the mean ripe fruit quality between trees with respect to fruit body rot severity (mainly anthracnose) with and without cold storage, internal disorders severity due to diffuse discolouration and vascular browning (after cold storage), days to ripen, percentage dry matter, and the percentage of the skin area with purple-black colour when ripe. These effects were also noted in the same orchard in 1999. There were significant (P<0.05) differences in fruit flesh calcium, magnesium, potassium, boron and zinc concentrations between trees. Significant (P<0.05) correlations were observed between average fruit mineral concentrations in each tree (particularly calcium, magnesium and potassium) and body rot severity, percentage dry matter and fruit mass. There was little conclusive evidence that characteristics such as the growth of the non-suberised roots or the degree of scion under- or overgrowth was involved in these tree effects; however, differences between trees with respect to other rootstock characteristics may be involved. The inconsistency of the correlations across sites and years suggested that other factors apart from tree influences could also affect the relationship between fruit minerals and fruit quality.

Impact of subsoil constraints on wheat yield and gross margin on fine-textured soils of the southern Victorian Mallee

The APSIM-Wheat module was used to investigate our present capacity to simulate wheat yields in a semi-arid region of eastern Australia (the Victorian Mallee), where hostile subsoils associated with salinity, sodicity, and boron toxicity are known to limit grain yield. In this study we tested whether the effects of subsoil constraints on wheat growth and production could be modelled with APSIM-Wheat by assuming that either: (a) root exploration within a particular soil layer was reduced by the presence of toxic concentrations of salts, or (b) soil water uptake from a particular soil layer was reduced by high concentration of salts through osmotic effects. After evaluating the improved predictive capacity of the model we applied it to study the interactions between subsoil constraints and seasonal conditions, and to estimate the economic effect that subsoil constraints have on wheat farming in the Victorian Mallee under different climatic scenarios. Although the soils had high levels of salinity, sodicity, and boron, the observed variability in root abundance at different soil layers was mainly related to soil salinity. We concluded that: (i) whether the effect of subsoil limitations on growth and yield of wheat in the Victorian Mallee is driven by toxic, osmotic, or both effects acting simultaneously still requires further research, (ii) at present, the performance of APSIM-Wheat in the region can be improved either by assuming increased values of lower limit for soil water extraction, or by modifying the pattern of root exploration in the soil pro. le, both as a function of soil salinity. The effect of subsoil constraints on wheat yield and gross margin can be expected to be higher during drier than wetter seasons. In this region the interaction between climate and soil properties makes rainfall information alone, of little use for risk management and farm planning when not integrated with cropping systems models.