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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Conducting Sensitive Research In The Present And Past Tense: Recounting The Stories Of Current And Former Child Domestic Workers, Natascha Klocker
Conducting Sensitive Research In The Present And Past Tense: Recounting The Stories Of Current And Former Child Domestic Workers, Natascha Klocker
Faculty of Science - Papers (Archive)
In recent years, scholarship on children's work has increasingly incorporated the perspectives of working children. Although laudable, this shift toward children's inclusion in research has concentrated on those employed at the time of data collection. Former child workers have largely been overlooked as a source of information. This paper reflects on research conducted with current and former child domestic workers in Tanzania. The child domestic working experiences reported by those two groups diverged markedly: those who had already ceased employment reported far higher rates of dissatisfaction with child domestic work, and far more experiences of exploitation and abuse, than those …
Conducting Composite Materials From The Biopolymer Kappa-Carrageenan And Carbon Nanotubes, Ali Aldalbahi, Jin Chu, Peter Feng, Marc In Het Panhuis
Conducting Composite Materials From The Biopolymer Kappa-Carrageenan And Carbon Nanotubes, Ali Aldalbahi, Jin Chu, Peter Feng, Marc In Het Panhuis
Faculty of Science - Papers (Archive)
Conducting composite films containing carbon nanotubes (CNTs) were prepared by using the biopolymer kappa-carrageenan (KC) as a dispersant. Rheological studies indicated that 0.5% w/v was the appropriate KC concentration for dispersing CNTs. Our results showed that multiwalled nanotubes (MWNTs) required less sonic energy than single-walled nanotubes (SWNTs) for the dispersion process to be complete. Films prepared by vacuum filtration exhibited higher conductivity and improved mechanical characteristics compared to those prepared by evaporative casting. All composite films displayed sensitivity to water vapour, but MWNT films were more sensitive than SWNT films.
Inkjet And Extrusion Printing Of Conducting Poly(3,4-Ethylenedioxythiophene) Tracks On And Embedded In Biopolymer Materials, Charles A. Mire, Animesh Agrawal, Gordon G. Wallace, Paul Calvert, Marc In Het Panhuis
Inkjet And Extrusion Printing Of Conducting Poly(3,4-Ethylenedioxythiophene) Tracks On And Embedded In Biopolymer Materials, Charles A. Mire, Animesh Agrawal, Gordon G. Wallace, Paul Calvert, Marc In Het Panhuis
Faculty of Science - Papers (Archive)
Two printing methods, extrusion and inkjet, are used to deposit tracks of PEDOT/PSS conducting polymer onto biopolymer films with a view to prepare implantable tissue mimics containing electronic devices. Extruded tracks offer lower printing resolution, but better electrical characteristics compared to inkjet printed tracks. The biopolymer–ink interaction results in narrower printed tracks compared to those on glass. This affects the final conductivity, which is lower for printed tracks on biopolymer than for lines printed on glass, due to the part of the track lying below the surface. Extrusion printing is used to embed tracks into a biopolymer matrix, resulting in …
Preparation And Characterisation Of Conducting Biopolymer-Carbon Nanotube Composite Materials, Ali Aldalbahi, Marc In Het Panhuis
Preparation And Characterisation Of Conducting Biopolymer-Carbon Nanotube Composite Materials, Ali Aldalbahi, Marc In Het Panhuis
Faculty of Science - Papers (Archive)
In this work, kappa-carrageenan (KC) is used to prepare composite dispersions consisting of single-walled (SWNTs) and multi-walled (MWNTs) carbon nanotubes. Free-standing composite films were prepared by evaporative casting and vacuum filtration of these dispersions.
Indanedione-Substituted Poly(Terthiophene)S: Processable Conducting Polymers With Intramolecular Charge Transfer Interactions, Klaudia K. Wagner, Loretta L. Crowe, Pawel W. Wagner, Sanjeev Gambhir, Ashton Partridge, John C. Earles, Tracey M. Clarke, Keith Gordon, David L. Officer
Indanedione-Substituted Poly(Terthiophene)S: Processable Conducting Polymers With Intramolecular Charge Transfer Interactions, Klaudia K. Wagner, Loretta L. Crowe, Pawel W. Wagner, Sanjeev Gambhir, Ashton Partridge, John C. Earles, Tracey M. Clarke, Keith Gordon, David L. Officer
Faculty of Science - Papers (Archive)
The electrochemical and chemical syntheses of poly(terthiophene)s bearing an indanedione pendant group and displaying intramolecular charge transfer interactions have been achieved. The nature of the charge transfer interaction is characterized through DFT calculations and experimental studies, including resonance Raman spectroscopy and absorption and emission data through a Lippert-Mataga analysis. It is found that the low-energy transition present in the indanedione-bearing monomer species has considerable charge transfer character with a dipole change of II D. Decomposition of the indanedione group occurred during hydrazine reduction after chemical polymerization. A soluble, low molecular weight indanedione-substituted polymer (weight average 4500 Da) was nonetheless obtained …
Inkjet Printed Conducting Gel-Carbon Nanotube Materials, A Aldalbahi, Marc In Het Panhuis
Inkjet Printed Conducting Gel-Carbon Nanotube Materials, A Aldalbahi, Marc In Het Panhuis
Faculty of Science - Papers (Archive)
The inkjet printing of CNTbiopolymer composite inks onto solid and gel substrates was investigated. Changing the substrate from glass to gel resulted in an increase in the resistance of printed materials from 9.85 kΩ/cm to 39.42 kΩ/cm.
Extrusion Printing Conducting Gel-Carbon Nanotube Structures Upon Flexible Substrates, Geoffrey Pidcock, Marc In Het Panhuis
Extrusion Printing Conducting Gel-Carbon Nanotube Structures Upon Flexible Substrates, Geoffrey Pidcock, Marc In Het Panhuis
Faculty of Science - Papers (Archive)
Extrusion printing was investigatedas a wet-processing method forfabrication of robust, flexible conductingstructures. Layer resistance values of 7 -8 kO/cm were obtained for one printedlayer on flexible substrates. Increasingthe number of extrusion printed layer significantlyimproved resistance.
6 Ghz Microstrip Patch Antennas With Pedot And Polypyrrole Conducting Polymers, Akhilesh Verma, Bo Weng, Roderick L. Shepherd, Christophe Fumeaux, Van Tan Truong, Gordon G. Wallace, Bevan D. Bates
6 Ghz Microstrip Patch Antennas With Pedot And Polypyrrole Conducting Polymers, Akhilesh Verma, Bo Weng, Roderick L. Shepherd, Christophe Fumeaux, Van Tan Truong, Gordon G. Wallace, Bevan D. Bates
Faculty of Science - Papers (Archive)
Two 6 GHz microstrip patch antennas made from conducting polymers with relatively low DC conductivity such as PEDOT (10000 S/m) and PPy (2000 S/m) are presented. The performance of these patch antennas is compared with a similar copper patch antenna. The results indicate that it is possible to obtain reasonable performance albeit with modest radiation efficiencies. The PEDOT antenna achieved a maximum gain of 2.2 dB, while the PPy antenna reached a gain of 3.8 dB, as against 6.0 dB for a corresponding Cu patch antenna The results confirm the potential of polymer materials for microwave antennas and suggest that …
Normal Stiffness Calibration Of Microfabricated Tri-Layer Conducting Polymer Actuators, Michael J. Higgins, Gursel Alici
Normal Stiffness Calibration Of Microfabricated Tri-Layer Conducting Polymer Actuators, Michael J. Higgins, Gursel Alici
Faculty of Science - Papers (Archive)
This paper reports on the stiffness characterization of microfabricated tri-layer conducting polymer (PPy) actuators. The rectangular, polypyrrole microactuators, which could operate both in aqueous and non-aqueous media, were fabricated using an excimer laser ablation technique that provided high throughput production and did not require cleanroom facilities. The microactuators were fixed at one end with electrical contacts and the other was end free to act as an electroactive microcantilever beam. An atomic force microscope (AFM) was used to measure the microactuator deflection under a range of normal forces applied by the AFM cantilever. A modified reference spring constant calibration method was …
Conducting Polymers With Fibrillar Morphology Synthesized In A Biphasic Ionic Liquid/Water System, J.M. Pringle, Orawan Ngamna, Carol M. Lynam, Gordon G. Wallace, Maria Forsyth, Douglas Macfarlane
Conducting Polymers With Fibrillar Morphology Synthesized In A Biphasic Ionic Liquid/Water System, J.M. Pringle, Orawan Ngamna, Carol M. Lynam, Gordon G. Wallace, Maria Forsyth, Douglas Macfarlane
Faculty of Science - Papers (Archive)
The synthesis of poly(pyrrole), poly(terthiophene), and poly(3,4-ethylenedioxythiophene) with unusual fibrillar morphologies has been achieved by chemical polymerization in a biphasic ionic liquid/water system. Use of aqueous gold chloride as the oxidant, with the monomers dissolved in a hydrophobic ionic liquid, allows the polymerization to occur at the ionic liquid/water interface. The resultant conducting polymer fibrils are, on average, 50−100 nm wide and can be thousands of nanometers long. The polymers produced in this ionic liquid system are compared to those synthesized in a biphasic chloroform/water system.
Synthesis, Modeling, And Characterization Of Conducting Polymers, Geoffrey M. Spinks, Lianbin Zhao, Weihua Li, Yanzhe Wu, Dezhi Zhou, Gordon G. Wallace
Synthesis, Modeling, And Characterization Of Conducting Polymers, Geoffrey M. Spinks, Lianbin Zhao, Weihua Li, Yanzhe Wu, Dezhi Zhou, Gordon G. Wallace
Faculty of Science - Papers (Archive)
This paper presents synthesis and characterization of polypyrrole based conducting polymers in terms of electronic and mechanical disciplines. Using the electrochemical polymerization approach, conducting polymer samples with different dimensions (length, width, and thickness) was fabricated. For each sample, both sinusoidal and step excitations were used to study its mechanical and electrical properties. An equivalent electric circuit based on constant phase element (CPE) is proposed to model such responses. Electrochemical impedance spectroscopy (EIS) method was used to identify the relationship between the dimensions of conducting polymers and model elements parameters.
Photoelectrochemical Cells Based On Inherently Conducting Polymers, Gordon G. Wallace, Chee O. Too, David L. Officer, Paul C Dastoor
Photoelectrochemical Cells Based On Inherently Conducting Polymers, Gordon G. Wallace, Chee O. Too, David L. Officer, Paul C Dastoor
Faculty of Science - Papers (Archive)
This review of photoelectrochemical cells (PECs) based on inherently conducting polymers (ICPs) deals with the mechanisms of operation and the various factors that influence the overall efficiency of PECs. The factors addressed include ICP composition and oxidation state, the use of nanostructured surfaces and interfaces, and the PEC electrolyte and redox mediator.