440 research outputs found

    Fostering Thinking Skills Through Creative Drama with Primary School Children with Learning Difficulties (LD) in Saudi Arabia

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    This study aimed to understand how the thinking skills of children with learning difficulties (LD) can be fostered by using ‘creative drama’ in the context of two primary schools for girls in Saudi Arabia. The educational vision of Saudi Arabia Vision 2030 emphasises the importance of the development of skills, such as thinking skills, in addition to knowledge to prepare children for a modern, 21st-century world. Within the Saudi educational system, relatively little attention has been paid to learners with LD, especially with thinking skills as a focus. The study utilised a design-based research approach involving multiple iterations of creative drama sessions incorporating different thinking skills, designed and co-led by the researcher and the teachers. The participants were 14 children with LD (ages 7 to 12) and two teachers with backgrounds in special educational needs. The study was designed in two phases. Phase One was carried out in School A to test and then revise the initial design principles empirically. The findings of this phase were an advanced version of the design principles, which then guided Phase Two in School B. The main findings of this intervention were introducing the elements of the dynamic and collaborative culture established through the use of creative drama for fostering thinking skills. The findings contribute to the empirical and theoretical field of fostering thinking skills using tested design principles for utilising ‘creative drama’ as a medium for teaching. The data were collected by multiple methods: teacher conversations, participant observations, focus groups, and a research journal. The findings suggest that using creative drama as a medium of learning might foster thinking skills by creating a dynamic and inclusive environment. Moreover, promoting the thinking skills of children with LD requires a balance between the facilitator’s role and the learners’ agency. It also requires a collaborative learning culture that supports the children emotionally and provides a safe atmosphere. This DBR concluded that the implementation of creative drama fostered the thinking skills of children with LD and allowed them to practise a variety of thinking skills in a safe, supportive environment and a collaborative culture. By considering the context of the Saudi educational system, this study suggests that there is a need to further investigate a thinking skills approach that supports learners with LD, and suggests the importance of investigating multi-modality and embodied cognition in special education, especially at the primary school level

    New inorganic nanomaterials for low-voltage transistor applications

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    This research aims to synthesise and characterise solution-processable high-k dielectric nanorods, which are potentially suitable for use as the dielectric layer in low-voltage Organic Field-Effect Transistor (OFET) applications. Oleic acid-stabilised titanium dioxide nanorods (TiO₂-OA), metal-doped anatase titanium oxide (TiO₂-OA-M; M=Nb, In, or Nb/In) nanorods, rutile titanium oxide nanorods (TiO₂) and barium titanium oxide nanorods (BaTiO₃) have been prepared and investigated.Solution processable oleic acid-stabilised titanium dioxide nanorods (TiO₂-OA) have been prepared by hydrolysis of titanium (IV) tetraisopropoxide (TTIP) with oleic acid (OA) as surfactant in the presence of trimethylamine N-oxide (TMAO). Furthermore, a series of ligand exchange reactions were carried out to replace the oleic acid bonded on the surface of TiO₂-OA with diethyl 2-phenylethyl phosphonate (DEPPNA), octadecylphosphonic acid (ODPA) or octylphosphonic acid (OPA). The ligand exchange rate was characterised by a combination of 31P liquid NMR, ICP, CHN, and FT-IR. The solubility of the ligand-exchanged products in chlorobenzene was also investigated.A novel method based on the co-hydrolysis of titanium (IV) tetraisopropoxide (TTIP) and niobium or/and indium isopropoxide or ethoxide has been investigated to prepare solution-processable, oleic acid- stabilised, niobium- and indium-doped, anatase TiO₂ nanorods (TiO₂-OA-M; M = Nb, In or Nb/In). The effect of niobium and indium precursors, the molar ratio of Nb or In precursors/TTIP and reaction time on the composition, structure and morphology of the Nb or In doped TiO₂ products have been investigated by a combination of XPS, XRD, ICP, CHN, FT-IR and TEM. Furthermore, a series of ligand exchange reactions were carried out to replace the oleic acid, which is bonded on the surface of TiO₂-OA-M, with diethyl 2-phenylethyl phosphonate (DEPPNA) or octadecylphosphonic acid (ODPA). The solubility of the products in chlorobenzene was also investigated.Rutile titanium dioxide nanorods with different sizes were prepared by three different approaches. In the first approach,hair-like rutile nanorods TiO₂ were prepared by simple hydrolysis of a TiOCl₂ solution at low temperature (50, 70 and 90 °C). In the second approach, rutile nanorods TiO₂ with a length of 150-200 nm and a width of 25-40 nm were prepared by using a hydrothermal treatment of TiOCl₂ at 220 °C. In the third approach, rutile nanorods TiO₂ with length of 80 nm and diameter of 20 nm were prepared by using an hydrothermal reaction of TiOCl₂ in the presence of 3-hydroxytyramine hydrogen chloride, [(HO)₂C₆H₃CH₂CH₂NH₂·HCl] at 150°C. In order to improve the solubility of the obtained rutile titanium dioxide nanorods in organic solvents, different surface-modification methods have been investigated to coat the surface of the rutile titanium dioxide nanorods with various organic ligands. In the first method, a modification of the TiO₂ nanorods with oleic acid (OA) in chlorobenzene was investigated. In the second method, a two-stage treatment of TiO₂ nanorods in an acidic medium was studied, using a selection of oleic acid (OA), diethyl 2-phenylethyl phosphonate (DEPPNA), octylphosphonic acid (OPA) and decylphosphonic acid (ODPA) as ligands. In the third method, wet TiO₂ nanorods before dry was directly modified with a range of oleic acid and amines, e.g., octylamine, dodecylamine and hexadecylamine, as ligands. All the products were characterized by a combination of XRD, ICP, CHN, FT-IR and TEM.The preparation of barium titanium oxide nanorods (BaTiO₃) has been investigated by different approaches. In the first approach, a hydrothermal reaction was carried out to convert the titanium dioxide nanorods prepared in the first and third parts in this research into BaTiO₃ nanorods. The effect of the molar ratio of Ba/Ti, the reaction pH, reaction time and temperature on the composition, structure and morphology of the products were fully investigated. In the second approach, a hydrothermal reaction using a single source Ba/Ti precursor, i.e., barium titanium ethylhexano-isoproxide BaTi(O₂CC₇H₁₅)(OC₃H₇)₅, was carried out to prepare barium titanium oxide nanorods. In the third approach, barium titanium oxide nanorods were prepared by using a hydrothermal reaction between barium chloride (BaCl₂) and titanium oxy chloride (TiOCl₂) in the presence of ethylene glycol as surfactant. All the products have been characterised by a combination of XRD, ICP, CHN, FT-IR and TEM

    DYNAMICS AND CONTROL OF REACTIVE DISTILLATION PROCESS FOR MONOMER SYNTHESIS OF POLYCARBONATE PLANTS

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    Polycarbonate (PC) is an important engineering thermoplastic that is currently produced in large industrial scale using bisphenol A and monomers such as phosgene. Since phosgene is highly toxic, a non-phosgene approach using diphenyl carbonate (DPC) as an alternative monomer, as developed by Asahi Corporation of Japan, is a significantly more environmentally friendly alternative. Other advantages include the use of CO2 instead of CO as raw material and the elimination of major waste water production. However, for the production of DPC to be economically viable, reactive-distillation units are needed to obtain the necessary yields by shifting the reaction-equilibrium to the desired products and separating the products at the point where the equilibrium reaction occurs. In the field of chemical reaction engineering, there are many reactions that are suffering from the low equilibrium constant. The main goal of this research is to determine the optimal process needed to shift the reactions by using appropriate control strategies of the reactive distillation system. An extensive dynamic mathematical model has been developed to help us investigate different control and processing strategies of the reactive distillation units to increase the production of DPC. The high-fidelity dynamic models include extensive thermodynamic and reaction-kinetics models while incorporating the necessary mass and energy balance of the various stages of the reactive distillation units. The study presented in this document shows the possibility of producing DPC via one reactive distillation instead of the conventional two-column, with a production rate of 16.75 tons/h corresponding to start reactants materials of 74.69 tons/h of Phenol and 35.75 tons/h of Dimethyl Carbonate. This represents a threefold increase over the projected production rate given in the literature based on a two-column configuration. In addition, the purity of the DPC produced could reach levels as high as 99.5% with the effective use of controls. These studies are based on simulation done using high-fidelity dynamic models

    The Need of an Optimal QoS Repository and Assessment Framework in Forming a Trusted Relationship in Cloud: A Systematic Review

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    © 2017 IEEE. Due to the cost-effectiveness and scalable features of the cloud the demand of its services is increasing every next day. Quality of Service (QOS) is one of the crucial factor in forming a viable Service Level Agreement (SLA) between a consumer and the provider that enable them to establish and maintain a trusted relationship with each other. SLA identifies and depicts the service requirements of the user and the level of service promised by provider. Availability of enormous service solutions is troublesome for cloud users in selecting the right service provider both in terms of price and the degree of promised services. On the other end a service provider need a centralized and reliable QoS repository and assessment framework that help them in offering an optimal amount of marginal resources to requested consumer. Although there are number of existing literatures that assist the interaction parties to achieve their desired goal in some way, however, there are still many gaps that need to be filled for establishing and maintaining a trusted relationship between them. In this paper we tried to identify all those gaps that is necessary for a trusted relationship between a service provider and service consumer. The aim of this research is to present an overview of the existing literature and compare them based on different criteria such as QoS integration, QoS repository, QoS filtering, trusted relationship and an SLA

    Requirements engineering aspects for sustainable eLearning systems

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    Sustainability in software engineering is about (1) continued functionality and maintainability in changing circumstances, and (2) functionality's effect on the surrounded environment, economic and people. Frequent changes of software requirements negatively affect sustainability of software systems. To reduce the number of requirements' changes and improve sustainability, sustainability requirements have to be considered from the beginning of the requirements engineering stage of software development. Sustainability in requirements engineering has five dimensions including individual, social, technical, economic and environmental dimensions. Most of the existing work analysed only one or two dimensions and ignore the interrelated effects among other dimensions. To address this issue, we selected eLearning systems because they provide comprehensive example to study. This thesis focuses on analysing sustainability requirements of eLearning systems with regard to the five sustainability dimensions. The following studies were performed: (1) identifying theoretically the sustainability requirements of eLearning systems, (2) investigating empirically the sustainability of eLearning systems, (3) constructing a methodology for the analysis and evaluation of sustainability requirements on eLearning systems, and (4) evaluating the constructed methodology. To the best of our knowledge, this is the first research conducted to investigate sustainability requirements of eLearning systems covering the five sustainability dimensions. Our findings highlighted that (1) technical, economic and environmental sustainability requirements are similar to other software domains, where individual and social sustainability requirements are specific for the domain of eLearning systems, (2) individual and social sustainability requirements need to be carefully considered and analysed together because of the strong correlation, and (3) culture and gender diversity play an important role for sustainability requirements. On this basis, we developed a framework for analysing sustainability requirements of software systems as well as a web-based tool SuSoftPro (the name stands from Software Sustainability Profiling) that allows requirements engineers to: investigate sustainability of software systems based on the systems' requirements, analyse the sustainability dimensions of software systems, measure the sustainability of each individual requirement, visualise analysis results to support decision making towards high-quality software, involve stakeholders to rate their requirements for one or more of the five sustainability dimensions, and manage requirement and stakeholder details easily. We evaluated the SuSoftPro framework through case studies, comparative evaluation and a quantitative questionnaire. Our framework successfully provides a comprehensive view of analysing sustainability requirements to improve the attention to sustainability and allow practitioners to develop sustainable software

    Iron ochre: a pre-catalyst for the cracking of methane

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    Background: Iron ochres are gelatinous sludges which can cause problems in terms of water management. In this manuscript, the application of iron ochre obtained from a river has been applied to catalytically crack methane – another potential waste product - into two useful products, hydrogen and a magnetic carbon containing composite.<p></p> Results: The powder XRD pattern of the iron ochre was found to be consistent with the expected 2-line ferrihydrite and EDX analysis showed Fe to be a major component although some Si was present. The sample was observed to contain a fraction with a tubular morphology consistent with the presence of extra-cellular biogenic iron oxide formed by leptothrix. Upon exposure to methane at elevated temperatures, the material was found to transform into an active catalyst for hydrogen production yielding a magnetic carbon containing composite material comprising filamentous carbon and encapsulating graphite.<p></p> Conclusion: The application of two waste products – iron ochre and methane – to generate two useful products – hydrogen and a magnetic carbon containing composite- has been demonstrated. Furthermore, the ochre has been shown to comprise tubular morphology extra-cellular biogenic iron oxide which may be of interest in terms of other applications.<p></p&gt

    Circular polarization switching and bistability in an optically injected 1300 nm spin-vertical cavity surface emitting laser

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    We report the experimental observation of circular polarization switching (PS) and polarization bistability (PB) in a 1300 nm dilute nitride spin-vertical cavity surface emitting laser (VCSEL). We demonstrate that the circularly polarized optical signal at 1300 nm can gradually or abruptly switch the polarization ellipticity of the spin-VCSEL from right-to-left circular polarization and vice versa. Moreover, different forms of PS and PB between right- and left-circular polarizations are observed by controlling the injection strength and the initial wavelength detuning. These results obtained at the telecom wavelength of 1300 nm open the door for novel uses of spin-VCSELs in polarization sensitive applications in future optical systems
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