984 resultados para CURRENT TRANSIENT SPECTROSCOPY


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Marble from the Chillagoe deposits was extensively used in the construction of Australia’s parliament house. Near infrared (NIR) spectroscopy has been applied to study the quality of marble from the Chillagoe marble deposits and to distinguish between different types of marble in the Chillagoe deposits. A comparison of the NIR spectra of marble with dolomite and monohydrocalcite is made. The spectrum of the marble closely resembles that of monohydrocalcite and is different from that of dolomite. The infrared spectra of the minerals are characterised by OH and water stretching vibrations. Both the first and second fundamental overtones of these bands are observed in the NIR spectra. Marble is characterised by NIR bands at 4005, 4268 and 4340 cm–1, attributed to carbonate combination bands and overtones. Marble also shows NIR bands at 5005, 5106, 5234 and 5334 cm–1 assigned to water combination bands. Finally the NIR spectrum of the marble displays broad low-intensity features centred upon 6905 cm–1 attributed to the water first overtones. It appears feasible to identify marble through the use of NIR spectroscopy.

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The mineral tilleyite-Y, a carbonate-silicate of calcium, has been studied by scanning electron microscopy with chemical analysis using energy dispersive spectroscopy (EDX) and Raman and infrared spectroscopy. Multiple carbonate stretching modes are observed and support the concept of non-equivalent carbonate units in the tilleyite structure. Multiple Raman and infrared bands in the OH stretching region are observed, proving the existence of water in different molecular environments in the structure of tilleyite. Vibrational spectroscopy offers new information on the mineral tilleyite.

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The approach to remove greenhouse gases by pumping liquid CO2 several kilometres below the ground implies that many carbonate containing minerals will be formed. Among these minerals, the formation of hydromagnesite, dypingite and nesquehonite are possible, thus necessitating a study of such minerals. These minerals with a hydrotalcite-related formulae have been characterised by a combination of infrared and near infrared spectroscopy. Layered double hydroxides (also known as anionic clays or hydrotalcites) are a group of layered clay minerals described by the general formula: [M1–x2+Mx3+(OH)2]x+[An–]x/n∙mH2O. The infrared spectra of the minerals are characterised by OH and water stretching vibrations. Both the first and second fundamental overtones of these bands are observed in the NIR spectra in the 7030–7235 cm–1 and 10,490–10,570 cm–1 spectral ranges. Intense (CO3)2– symmetrical and anti-symmetrical stretching vibrations confirm the distortion of the carbonate anion. The position of the water bending vibration indicates water is strongly hydrogen-bonded to the carbonate anion in the mineral structure. NIR spectroscopy offers a method for quickly analysing such materials.

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This case study investigated EFL assessment practices at one public and one private university to explore the support of assessment for English language learning (ELL) within the Vietnamese sociocultural context. Findings demonstrated the potential of assessment to engage students in learning; enhance their understanding of the learning objectives; and facilitate their learning reflection. Findings also identified strong influences of contextual factors such as teachers' language assessment literacy, high-stakes testing and institutional administrative policies on the practices of assessment for ELL. This study contributes to research on Assessment for Learning and EFL education at tertiary level in Vietnam and other similar sociocultural contexts.

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This thesis provides a review of 199 papers published on Green IT/IS between 2007−2014, in order to present taxonomy of segments in Green IT/IS publications, where the segments are later used for multiple analyses to facilitate future research and to provide a retrospective analysis of existing knowledge and gaps thereof. This research also attempts to make a unique contribution to our understanding of Green IT/IS, by consolidating papers it observes current patterns of literature through approach analysis and segmentation, as well as allocating studies to the technology, process, or outcome (TPO) stage. Highlighting the necessity of a consolidated approach, these classification systems have been combined into a TPO matrix so that the studies could be arranged according to which stage of the Green IT/IS cycle they were focused on. We believe that these analyses will provide a solid platform from which future Green IT/IS research can be launched.

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BACKGROUND Ongoing shortages of blood products may be addressed through additional donations. However, donation frequency rates are typically lower than medically possible. This preliminary study aims to determine voluntary nonremunerated whole blood (WB) and plasmapheresis donors' willingness, and subsequent facilitators and barriers, to make additional donations of a different type. STUDY DESIGN AND METHODS Forty individual telephone interviews were conducted posing two additional donation pattern scenarios: first, making a single and, second, making multiple plasmapheresis donations between WB donations. Stratified purposive sampling was conducted for four samples varying in donation experience: no-plasma, new-to-both-WB-and-plasma, new-to-plasma, and plasma donors. Interviews were analyzed yielding excellent (κ values > 0.81) inter-rater reliability. RESULTS Facilitators were more endorsed than barriers for a single but not multiple plasmapheresis donation. More new-to-both donors (n = 5) were willing to make multiple plasma donations between WB donations than others (n = 1 each) and identified fewer barriers (n = 3) than those more experienced in donation (n = 8 no plasma, n = 10 new to both, n = 11 plasma). Donors in the plasma sample were concerned about the subsequent reduced time between plasma donations by adding WB donations (n = 3). The no-plasma and new-to-plasma donors were concerned about the time commitment required (n = 3). CONCLUSION Current donors are willing to add different product donations but donation history influences their willingness to change. Early introduction of multiple donation types, variation in inventory levels, and addressing barriers will provide blood collection agencies with a novel and cost-effective inventory management strategy.

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Erythropoietin (EPO), a glycoprotein hormone of ∼34 kDa, is an important hematopoietic growth factor, mainly produced in the kidney and controls the number of red blood cells circulating in the blood stream. Sensitive and rapid recombinant human EPO (rHuEPO) detection tools that improve on the current laborious EPO detection techniques are in high demand for both clinical and sports industry. A sensitive aptamer-functionalized biosensor (aptasensor) has been developed by controlled growth of gold nanostructures (AuNS) over a gold substrate (pAu/AuNS). The aptasensor selectively binds to rHuEPO and, therefore, was used to extract and detect the drug from horse plasma by surface enhanced Raman spectroscopy (SERS). Due to the nanogap separation between the nanostructures, the high population and distribution of hot spots on the pAu/AuNS substrate surface, strong signal enhancement was acquired. By using wide area illumination (WAI) setting for the Raman detection, a low RSD of 4.92% over 150 SERS measurements was achieved. The significant reproducibility of the new biosensor addresses the serious problem of SERS signal inconsistency that hampers the use of the technique in the field. The WAI setting is compatible with handheld Raman devices. Therefore, the new aptasensor can be used for the selective extraction of rHuEPO from biological fluids and subsequently screened with handheld Raman spectrometer for SERS based in-field protein detection.

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Increasing worldwide terrorist attacks involving explosives presents a growing need for a rapid and ranged explosive detection method that can safely be deployed in the field. Stand-off Raman spectroscopy shows great promise; however, the radiant exposures of lasers required for adequate signal generation are often much greater than what is safe for the eye or the skin, restricting use of the technique to un-populated areas. Here, by determining the safe exposure levels for lasers typically used in Raman spectroscopy, optimal parameter values are identified, which produce the largest possible detection range using power densities that do not exceed the eye-safe limit. It is shown that safe ultraviolet pulse energies can be more than three orders of magnitude greater than equivalent safe visible pulse energies. Coupling this to the 16-fold increase in Raman signal obtained in the ultraviolet at 266 nm over that at 532 nm results in a 131 times larger detection range for the eye-safe 266-nm system over an equivalent eye-safe 532-nm laser system. For the Raman system described here, this translates to a maximum range of 42 m for detecting Teflon with a 266-nm laser emitting a 100-mm diameter beam of 23.5-mJ nanosecond pulses.

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We report a new organic photovoltaics (OPV) design, a wrapped OPV, which can circumvent both challenges of short exciton diffusion length [1], and low charge carrier mobility [2] of organic semiconductors by orienting the OPV vertically, to capture; manage; guide and use all incident photons and therefore, generate higher current. Resonant light, on being transmitted into a wrapped OPV, makes multiple passes through the photoactive layer and is absorbed completely, thus achieving benefits of thick photoactive layer while maintaining its ultra-thin thickness requirement. The current density generated from a wrapped OPV is twice than that generated by a similar OPV with flat orientation.

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An improved understanding of the characteristics of the pre-discharge current pulses in GIS will lead to improved analyses of the results from the UHF partial discharge detection method. This paper presents the characteristics of the first pre-discharge current pulses from a point-to-plain geometry at 1 bar absolute under both polarities of a 1.1/80 us lightning impulse. The analysis has shown that the pre-discharge current wave shape, peak current magnitude and charge is effected by the instantaneous voltage at which the pre- discharge took place as well as the polarity of the active electrode. The measured results show that protrusions on the electrodes have slower wave shape parameters than those reported for free conducting particles.

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Encroaching built environment with increased fault current levels is demanding a robust design approach and prolonged improved performance of the earth grid. With this in mind, the aim of the project was to perform a sensitivity analysis of the earth grid and an earthing performance evaluation with graphene coated conductors. Subsequent to these, a conceptual design to continuously monitor the performance of the earth grid was developed. In this study, earth grid design standards were compared to evaluate their appropriate use in determining the safety condition. A process to grow a thin film of graphene on the surface of cylindrical copper rods was developed to evaluate earthing performance in terms of conductivity and corrosion susceptibility.

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Diketopyrrolopyrole-naphthalene polymer (PDPP-TNT), a donor-acceptor co-polymer, has shown versatile behavior demonstrating high performances in organic field-effect transistors (OFETs) and organic photovoltaic (OPV) devices. In this paper we report investigation of charge carrier dynamics in PDPP-TNT, and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) bulk-heterojunction based inverted OPV devices using current density-voltage (J-V) characteristics, space charge limited current (SCLC) measurements, capacitance-voltage (C-V) characteristics, and impedance spectroscopy (IS). OPV devices in inverted architecture, ITO/ZnO/PDPP-TNT:PC71BM/MoO3/Ag, are processed and characterized at room conditions. The power conversion efficiency (PCE) of these devices are measured ∼3.8%, with reasonably good fill-factor 54.6%. The analysis of impedance spectra exhibits electron’s mobility ∼2 × 10−3 cm2V−1s−1, and lifetime in the range of 0.03-0.23 ms. SCLC measurements give hole mobility of 1.12 × 10−5 cm2V−1s−1, and electron mobility of 8.7 × 10−4 cm2V−1s−1.

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Aim To document current practice by dietitians in Australia and Canada in the nutrition management of Parkinson's disease. This will help identify priority areas for review and development of practice guidelines and direct future research. Methods Current practice in the phases of the Nutrition Care Plan was captured using an online survey distributed to Dietitians Association of Australia members and Practice-Based Evidence in Nutrition subscribers through their email newsletters. The results of the diagnosis, intervention and monitoring phases are presented here. Results Eighty-four dietitians responded. There was consistency in practice for nutrition issues that are encountered in other populations, such as malnutrition and constipation. There was more variation in practice in the nutrition issues that are more specific to Parkinson's disease, such as nutrition and meal interactions with medication. A lack of awareness of emerging treatments, such as deep brain stimulation surgery, appears to exist in the responding dietitians. Conclusions The variation in practice that was present for the nutrition issues specific to Parkinson's disease may reflect the lack of quality evidence and subsequently evidence-based guidelines in these areas. Work to provide background information about treatment options and to translate current evidence for the nutrition issues that are specific to Parkinson's disease into practice recommendations should be completed.

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Workshops and seminars are widely-used forms of doctoral training. However, research with a particular focus on these forms of doctoral training is sporadic in the literature. There is no, if any, such research concerning the international context and participants’ own voices. Mindful of these lacunae in the literature, we write the current paper as a group of participants in one of a series of doctoral forums co-organised annually by Beijing Normal University, China and Queensland University of Technology, Australia. The paper voices our own experiences of participation in the doctoral forum. Data were drawn from reflections, journals, and group discussions of all 12 student and academic participants. These qualitative data were organised and analysed through Bourdieu’s notions of capital and field. Findings indicate that the doctoral forum created enabling and challenging social fields where participants accrued and exchanged various forms of capital and negotiated transient and complex power relations. In this respect, the sociological framework used provides a distinctive theoretical tool to conceptualise and analyse the benefits and tensions of participation in the doctoral forum. Knowledge built and lessons learned through our paper will provide implications and recommendations for future planning of, and participation in, the doctoral forum series and similar activities elsewhere.

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The influence of fluid flow, surface roughness and immersion time on the electrochemical behaviour of carbon steel in coal seam gas produced water under static and hydrodynamic conditions has been studied. The disc electrode surface morphology before and after the corrosion test was characterized using scanning electron microscopy (SEM). The corrosion product was examined using X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD).The results show that the anodic current density increased with increasing surface roughness and consequently a decrease in corrosion surface resistance. Under dynamic flow conditions, the corrosion rate increased with increasing rotating speed due to the high mass transfer coefficient and formation of non-protective akaganeite β- FeO(OH) and goethite α- FeO(OH) corrosion scale at the electrode surface.The corrosion rate was lowest at 0 rpm.The corrosion rate decreased in both static and dynamic conditions with increasing immersion time. The decrease in corrosion rate is attributed to the deposition of corrosion products on the electrode surface. SEM results revealed that the rougher surface exhibited a great tendency toward pitting corrosion.