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Novel materials for moist wound management: alginate-psyllium hybrid fibres
No full textObjective: To assess the feasibility of producing high absorbing, high gelling hybrid fibres made from alginate and psyllium. Method: Three methods of psyllium extraction were attempted: the hot, cold and hydrolysed method. The extracted psyllium was sieved before addition to the alginate dope. To assess feasibility, each dope was in turn extruded on a bench-top extruder and then on a pilot-size wet extruder. Calcium chloride solution was used as the coagulation medium for all the extrusions. The produced fibres were subsequently assessed for their linear density, tensile strength, absorption characteristics and swelling behaviour. Optical microscopy was also used to illustrate hybrid fibre swelling behaviour under different conditions Results: This feasibility study has shown that hybrid fibres can be produced when using different methods of psyllium extraction, proving the feasibility of the proposed methodology. However, based on physical and functional assessment of the fibres, it was found that the cold water extraction method leads to better hybrid fibres with superior tensile properties, liquid absorption and swelling, which would render them most suitable for heavily exudating wounds. Conclusion: The cold water route is found to be the most effective way of producing polysaccharide-based hybrid fibres. This method is also the least expensive, both in terms of room temperature preparations and functional effectiveness, using only 0.75% psyllium. This fibre is therefore recommended for wound dressing applications
The Bolton Review: Issue 1: Whiskey and donuts
No full textThe first issue of the Bolton Review was published online only in May 2014 by editors and creative writing students Bryony Harwood, Fozia Parveen and Rachel Bresnahan and executive editor and lecturer Dr Simon Holloway. The Bolton Review is a creative writing magazine, set up by members of the Creative Writing team of the University of Bolton to allow its students and staff to submit creative works of all types
Development of thin film photovoltaic cells based on low cost metal oxides
No full textThe major market barriers to the use of photovoltaic solar cells are high cost and long payback time of conventional technologies, based largely on the silicon material. In order to overcome the environmental problem resulting from the consumption of fossil fuels, all western countries are required to impose heavy subsidies to encourage the use of solar cells in the reduction of carbon consumption; thereby making them highly unsustainable.Therefore, it is necessary to develop solar cells based on low-cost metal oxides with large natural resources.The objective of this program is to investigate the effects of doping on the structural, optical and electrical properties of low-cost metal oxides, such as doped ZnO and copper oxides (CuO and Cu4O3). These are synthesised via sputter deposition and thermal oxidation method in air.Al doped ZnO is an n-type direct semiconductor with a band gap of around 3.5eV. Its crystalline structure is wurtzite, which is deposited widely by the RF reactive magnetron sputtering technology. In my work, the Al doped ZnO thin films were deposited by sputter with metal and ceramic targets. On the one hand, the influence of RF power on the structural, electrical and optical properties of Al doped ZnO thin films were investigated when they were deposited with metal targets. Conversely, the influence of O2 flow rate on the structural, electrical and optical properties of Al doped ZnO thin films was examined when they were deposited with ceramic targets.CuO is a p-type indirect semiconductor with a narrow band gap of 1.0-1.4eV.Its crystalline structure is monoclinic crystal system. CuO nanowires (NWs) were fabricated by the thermal oxidation method in air. It was found that CuO NWs not only grows on Cu sheets, but also on the Si, FTO, Al doped ZnO and glass substrates. For the growth of CuO NWs, the expanding parameters should meet the following requirements: growing temperature:>390°C and growing duration: ≥6hrs. The peeling-off of the CuO NWs on Cu sheets resulted from the formation of Cu8O and Cu64O between the Cu sheets and Cu2O layer.The electrical properties of a single CuO NW were measured using a nano probe station. The contact behaviour between a CuO NW and metal electrodes (Au and W) was schottky. The electrical resistivity of a CuO NW depended on the diameter of the NW. The contact behaviour between CuO NWs on Cu sheets with silver paste top electrodes was schottky as well. A simple PV cell based on CuO NWs-PCBM p-n heterojunction was fabricated, and the short circuit current, open voltage and fill factor of the PV cell was also measured. It indicated that CuO NWs can be utilized to fabricate diodes and PV cells.Copper oxides thin films were deposited by RF reactive magnetron sputtering technology. The phase structure of copper oxides thin films depended on the sputtering parameters. When the thin film was deposited without a bias power, only CuO was detected in the copper oxide thin films.The electrical properties of CuO thin films depended on the O2 fraction during the sputter process. The current-voltage (I-V) characteristics of CuO thin films with Cu electrodes demonstrated that it was influenced by the O2 fraction during the sputter process.Moreover, Cu4O3 is a p-type indirect semiconductor with narrow band gap of 1.0-1.4eV and its crystalline structure is tetragonal crystal system. When the copper oxide thin films were deposited with a bias power, only Cu4O3 phase was detected. Its structural, optical and electrical properties were studied.The optical band gap of Cu4O3 thin film was 1.37eV. Hall properties of Cu4O3 thin films were 1020cm-3, 10-2cm2·V-1·s-1 and 10-1Ω·cm. The Cu4O3-Al Abstract III doped ZnO p-n heterojunction demonstrated excellent rectifying performance, indicating that Cu4O3 is a good candidate for fabricating diodes and PV cells. In addition, Cu4O3 thin films were annealed at different temperatures in air. Furthermore, I studied the influence of annealing temperature on the structural, optical and electrical properties of Cu4O3 thin films
Interplay between sugar and hormone signaling pathways modulate floral signal transduction
No full textThe juvenile-to-adult and vegetative-to-reproductive phase transitions are major determinants of plant reproductive success and adaptation to the local environment. Understanding the intricate molecular genetic and physiological machinery by which environment regulates juvenility and floral signal transduction has significant scientific and economic implications. Sugars are recognized as important regulatory molecules that regulate cellular activity at multiple levels, from transcription and translation to protein stability and activity. Molecular genetic and physiological approaches have demonstrated different aspects of carbohydrate involvement and its interactions with other signal transduction pathways in regulation of the juvenile-to-adult and vegetative-to-reproductive phase transitions. Sugars regulate juvenility and floral signal transduction through their function as energy sources, osmotic regulators and signaling molecules. Interestingly, sugar signaling has been shown to involve extensive connections with phytohormone signaling. This includes interactions with phytohormones that are also important for the orchestration of developmental phase transitions, including gibberellins, abscisic acid, ethylene, and brassinosteroids. This article highlights the potential roles of sugar-hormone interactions in regulation of floral signal transduction, with particular emphasis on Arabidopsis thaliana mutant phenotypes, and suggests possible directions for future research
Comparative study on microfluidic performance of ZnO surface acoustic wave devices on various substrates
No full textZnO thin film-based surface acoustic wave (SAW) devices were fabricated on Si, glass and polyimide (PI) substrates, and their microfluidic performances were compared. The Rayleigh and Sezawa mode waves were observed from the ZnO/Si devices, the Rayleigh and Lamb modes from the ZnO/PI, and only the Rayleigh mode from the ZnO/glass devices. The ZnO/Si devices have the best performance with the highest acoustic streaming velocity of about 10 cm/s and the shortest particle concentration time of less than 10 sec. The ZnO/glass SAW devices deliver comparable performances to that on Si substrate, while the ZnO/PI devices perform not as good as the devices on other two types of substrates due to the large acoustic attenuation, but still can deliver a streaming velocity up to 1.0 cm/s and reasonable particle concentration function with a particle concentration time of ∼70 sec. Owing to its low cost, easy fabrication and compatible with traditional glass-based biochemical analysis systems, ZnO/glass SAW device is believed to have better potential for lab-on-a-chip application
Ply level failure prediction of carbon fibre reinforced laminated composite panels subjected to low velocity drop-weight impact using adaptive meshing techniques
No full textThis work is concerned with physical testing and numerical simulations of flat and round nose drop-weight impact of carbon fibre-reinforced laminate composite panels to predict ply level failure. Majority of the existing studies on impact of composites by spherical nose impactors are experimental, computational models are simplified, and based on classical laminated plate theories where contributions of through-thickness stresses are neglected. Present work considers flat nose impact and contributions from through-thickness stresses and is mainly simulation based. A computational model was developed in ABAQUS (TM) software using adaptive meshing techniques. Simulation produced (2D model) stresses were numerically integrated using MATALB (TM) code to predict through-thickness (3D) stresses. Through-the-thickness stresses were then utilised in advanced failure criteria coded in MATLAB (TM) software to predict ply level failures. Simulation produced results demonstrate that the computational model can efficiently and effectively predict ply-by-ply failure status of relatively thick laminates. (C) 2014 Published by Elsevier Ltd. on behalf of IAA
A Coming or Going of Age? Children's Literature at the Turn of the Twenty-First Century
No full textChildren’s literature, as a discrete entity, is commonly traced back to the eighteenth century in England, to a time when the new middle classes began to carve out a protected space for their progeny. Distinct commodities were developed, including games, furniture and clothing — and, of course, books, seen as perfect vehicles to instruct and entertain the future citizenry. The Romantics rounded out and mythologised this new being, the child, as innocent, pure and, therefore, unsullied by adult society. By the end of the Victorian period, the ‘cult of the child’, as it became known, was at its height, with the desirability of remaining a child, a Peter Pan, in the cultural ascendant. However, a century on from the fin de siècle, at the fin de millennium, this image had been severely questioned. The ‘century of the child’, as Ellen Kay (1900/1909) then termed it, had ended, and with it, a growing number of voices proclaimed a new century that foresaw the child’s disappearance, or death, even (Winn 1984; Postman 1994; Buckingham 2000). This chapter explores how this crisis over the child manifests itself in the era of Thatcher’s grandchildren. On the one hand, there are writers who celebrate a new freedom to discuss issues more candidly with children — whether about war, the Holocaust, homelessness, the family, racism, abuse, drugs, ecology, or sex and sexuality — whereas others fear that this very openness is destroying childhood, formerly defined in terms of protection, of relative innocence
Bendable ZnO thin film surface acoustic wave devices on polyethylene terephthalate substrate
No full textBendable surface acoustic wave (SAW) devices were fabricated using high quality c-axis orientation ZnO films deposited on flexible polyethylene terephthalate (PET) substrates at a low temperature of 120 ℃. Dual resonance modes, namely, the zero order pseudo asymmetric (A0) and symmetric (S0) Lamb wave modes, have been obtained from the SAW devices. The SAW devices are very flexible and durable, and perform well even after being bent with a large strain of 2500 με up to 100 times, demonstrated its suitability for the application in flexible electronics. The SAW devices were also found highly sensitive to compressive and tensile forces, exhibiting excellent anti-strain deterioration property, thus they are particularly suitable for the application in sensing large strains