45,383 research outputs found
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
Analysing International Sports Fan Motivations and Constraints: The Case of Japanese International Sports Fan Tourists and Rugby World Cup Fan Tourists
No full textThe scale of professional sports leagues and mega sports events has expanded recently. Many sports fans travel to foreign countries to watch international events featuring the world’s top athletes or players. The number of international sports fan tourists has increased, and understanding their behaviour is very important for stakeholders and those involved in marketing, such as sports organisations, travel companies, and government tourist organisations.
This study examines the motivations and constraints of Japanese international sports fan tourists and Japanese Rugby World Cup fan tourists. Sports fan tourists are tourists as well as sports fans. Many researchers have examined motivation either from a sports fan’s perspective or a tourist perspective. However, a motivation scale for international sports fan tourists (combining both sports fan and tourist motivations) has been not developed as there has been a lack of research into the behaviour of the international sports fan tourist.
The main research aim of this study is to analyse the motivation and constraint factors of both Japanese international sports fan tourists and Japanese Rugby World Cup tourists. The methodology aims to:
1.profile Japanese international sports fan tourists and Japanese Rugby World Cup tourists;
2.develop a motivational scale for actual sports fan tourists and a constraints scale for potential sports fan tourists (those who considered going but did not go);
3.analyse these factors according to demographics;
4.examine factors related to motivations and constraints on fans’ satisfaction, or their intention to attend future events.
A quantitative approach was employed. The main data collection methods were three email surveys:
1.Study 1 collected data about actual international sports fan tourists (N=338) and potential sports fan tourists (N=292).
2.Study 2 collected data about actual Rugby World Cup 1987-2007 tourists (N=101) and potential tourists (N=297).
3.Study 3 collected data about actual Rugby World Cup 2011 tourists (N=84) and potential tourists (N=115).
In previous studies, the sample was collected either from actual fans or potential fans separately; however, in this study, samples were collected not only from actual sports fan tourists but also from potential sports fan tourists from the same database.
The data analysis predominantly used explanatory factor analysis (EFA), confirmatory factor analysis (CFA), independent t-test, ANOVA, regression analysis, and structure equation modelling (SEM) including interaction effects analysis.
The results of this study were analysed using four steps:
1.Showing the demographic profiles and behavioural patterns of Japanese international sports fan tourists and Japanese Rugby World Cup fan tourists.
2.Developing motivation and constraints scales:
• an International Sports Fan Motivation Scale
• an International Sports Fan Tourist Motivation Scale
• an International Sports Fan Constraints Scale
• a Rugby World Cup Sports Fan Motivation Scale
• a Rugby World Cup Fan Tourist Motivation Scale
• a Rugby World Cup Fan Constraints Scale.
3.Comparing the mean scores of extracted factors by demographics such as gender, age, sports experiences etc.
4.Analysing the impact on satisfaction or future intention using interaction effect methods.
The results showed some interesting academic and practical implications. This study has thus made a significant and unique contribution to the knowledge of international sports fan behaviour by researching the combined sports fan motivation factors and tourist motivation factors of actual sports fans, and the constraints of potential sports fan tourists. The study has also provided an academic contribution to the sports and tourism fields, and has provided a practical contribution to the areas of sports fan behaviour, tourism, leisure constraints, and sports events management
Use of fan rig data for the understanding and prediction of fan broadband noise and noise changes due to a variable area nozzle
No full textThis thesis presents the results of the research component of this EngD, entitledUse of fan rig data for the understanding and prediction of fan broadband noise and noisechanges due to a variable area nozzleAs suggested by the title, fan rig noise measurements form an integral part of this thesis. Theanalysis of a database of rig noise measurements forms the first section of this thesis, in twoparts. The first part describes the analysis of a set of fan rig noise measurements, including thevariation of fan broadband and tone noise in forward and rearward arcs. The second partexamines a large database of fan rig noise measurements, and attempts to derive correlationsof fan broadband noise and fan performance parameters. Cluster Analysis, PrincipleComponent Analysis, and Regression Analysis are used to understand and describe theunderlying physics of broadband noise generation and the relationships between thesepredictors.The second section of this thesis uses a cascade broadband noise model to investigate rotorstatorbroadband noise. Predictions of the broadband noise from this noise model arecompared to rig measurements, showing good accuracy. The underlying physics of rotorstatorbroadband noise generation is investigated by performing two parametric studies usingthe broadband noise model. The first parametric study investigates the effect on broadbandnoise of simple flow and geometric parameters, namely number of vanes, vane chord, vanestagger angle, and rotor wake turbulence intensity, turbulent length scale, and flow Machnumber onto the cascade. These results are used to derive scaling power laws for theprediction of changes in broadband noise due to changes in these parameters. The secondparametric study expands upon this by investigating the effect on broadband noise of the fandesign parameters shaft speed, pressure ratio, and efficiency, at approach, cutback and cruiseconditions. The variation in broadband noise due to these design parameters is explained byconsidering the underlying flow and geometric parameters such as number of vanes and Machnumber, and the scaling power laws based on these simple parameters are used to predict thechange in broadband noise between different performance points.The final section of this thesis investigates the effect of varying exhaust nozzle area on totalengine noise. A new method is presented that allows the transfer of changes in fan rig noise toEugene P. Deane EngD Thesis September 2009 2engine noise predictions, to estimate the change in fan noise due to the pressure ratio changesbrought about by a variable area nozzle. Changes in engine noise are investigated forapproach, cutback, and sideline conditions, and the application of the new method assessed.As the research displayed in this thesis is closely linked to industry, the foundation of workpresented in several chapters is dependent on data or figures that are commercially sensitive.It has therefore been necessary to create a confidential appendix (Appendix X) to includethese commercially sensitive items. These additional results and figures in Appendix X aresupplementary in nature, and sufficient results are presented in the public thesis to illustratethe results of the various chapters. Where supplementary information and results are available,this is clearly indicated at the pertinent point in the published thesis, along with the section ofAppendix X where the information can be found
Experimental study of blade thickness effects on the global and local performances of a Controlled Vortex Designed axial-flow fan
No full textThe purpose of this work is to study the effects of blade thickness on the performances of an axial-flow fan. Two fans that differ only in the thickness of their blades were studied. The first fan was designed to be part of the cooling system of an automotive vehicle power unit and has very thin blades. The second fan has much thicker blades compatible with the rotomoulding conception process. The global performances of the fans were measured in a test bench designed according to the ISO-5801 standard. The curve of aerodynamics characteristics (pressure head versus ow-rate) is slightly steeper for the fan with thick blades, and the nominal point is shifted towards lower flow-rates. The efficiency of the thick blades fan is lower than the efficiency of the fan with thin blades but remains high on a wider flow-rate range. The mean velocity field downstream of the rotors are very similar at nominal points with less centrifugation for the thick blades fan. The thick blades fan moreover maintains an axial exit-flow on a wider range of flow-rates. The main dierences concern local properties of the flow: Phase-averaged velocities and wall pressure fluctuations strongly differ at the nominal flow-rates. The total level of fluctuations is lower for the thick blades fan that for the thin blades fan and the spectral decomposition of the wall fluctuations and velocity signals reveal more harmonics for the thick blades fan, with less correlation between the different signals. For this kind of turbomachinery, the use of thick blades could lead to a good compromise between aerodynamic and acoustic performances, on a wider operating range
Air and Water Flowrate Optimisation for a Fan Coil Unit in Heat Pump Systems
No full textThe degradation in efficiency of auxiliary components in heating/cooling systems when operating at part load is frequently reported. Through the use of variable speed components, the supplied capacity can be reduced to match the required load and hence reduce unnecessary energy consumption. However, for fan coil units, difficulties can arise when optimizing fan and pump speeds at part load. Practically locating optimal water and air flow rates from readily available information and for varying supplied capacities is necessary, in order to reduce the fan coil power consumption. This research attempts to identify whether optimal fan and pump speeds exist for a fan coil unit and how they can be implemented, in a practical manner, in a system control applications. Using an empirical fan coil and pump model, the total power consumption (fan and pump) for different combinations of fan and pump speeds over a range of capacities was calculated. It was observed that, for a given capacity, an optimal combination of fan and pump speeds exists and there was a significant change in power consumption for different combinations of fan and pump speeds supplying the same capacity. A control strategy is described that utilizes a simple fan coil capacity estimation model, coupled with air and water flow rates, along with nominal design data. The pump speed is optimized using PID control to maintain the space temperature at the chosen set-point, which matches the supplied capacity to the required capacity. At set-time intervals, the capacity estimation model is utilized to optimize the water and air flow rates for the required capacity. The control strategy is evaluated, using a full building simulation model for a daily load profile and is compared to two baseline conditions: for no control of the fancoils/pump combination and for PID circulation control of the pump only. The optimal fan and pump speed control resulted in a 43% and 24% decrease in power consumption with compared to the no control baseline and the PID controlled circulation pump strategy, respectively
Development of a Method for Enhanced Fan Representation in Gas Turbine Modeling
No full textA challenge in civil aviation future propulsion systems is expected to be the integration with the airframe, coming as a result of increasing bypass ratio or above wing installations for noise mitigation. The resulting highly distorted inlet flows to the engine, make a clear demand for advanced gas turbine performance prediction models. Since the dawn of jet engine several models have been proposed and the present work comes to add a model that combines two well established compressor performance methods in order to create a quasi three dimensional representation of the fan of a modern turbofan. A streamline curvature model is coupled to a parallel compressor method, covering radial and circumferential directions respectively. Model testing has shown a close agreement to experimental data, making it a good candidate for assessing the loss of surge margin on a high bypass ratio turbofan, semi-embedded on the upper surface of a broad wing airframe
FAN 2002: um modelo neuro-fuzzy para reconhecimento de padrões
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.Nesta tese é apresentado FAN 2002 - free associtive neurons - como uma abordagem neuro-fuzzy para reconhecimento supervisionado de padrões. Aspectos foram modificados desde a sua publicação inicial, em 1997: a criação de células para a combinação de características é substituida pela inclusão de uma característica extra que representa a combinação das demais; a forma de realizar a penalização em caso de erro é modificada; a inicialização dos neurônios é realizada com valores aleatórios; um hedge é usado no teste de um padrão. Os resultados em aplicações são mostrados: no problema de classificação de cromossomos, a comparação com os resultados o obtidos por outros métodos apresentados ilustra o desenvolvimento do modelo desde as suas primeiras implementações; A aplicação do modelo em jogos de empresas na construção de um agente; Os conceitos de FAN na construção dos Mapas FAN e a solução do problema do XOR. A apresentação de FAN 2002 visa proporcionar aos interessados na aplicação de soluções em reconhecimento de padrões uma ferramenta útil e de uso geral.A conclusão do trabalho mostra o resumo dos avanços obtidos no desenvolvimento de FAN e aponta para o futuro do método uma possibilidade interdisciplinar de subsidiar pesquisadores de outras áreas a resolverem os seus próprios problemas de classificação e reconhecimento
Different types of gravity-driven flow deposits and associated bedforms in the Upper Bengal Fan, offshore Myanmar
No full textThis study uses 3D reflection seismic data to investigate how sediment gravity flows contribute to the evolution of the lower continental slope of the Myanmar margin that is part of the Bengal Fan, the largest deep-water fan system in the world. Seafloor and subseafloor data show large sediment wave fields that developed on both flanks of an extensive submarine canyon. The sediment waves exhibit asymmetric stoss and lee sides, wave lengths and heights of 850–3000 m and 25–70 m, respectively, and an upslope direction of migration. Seismic data reveals the presence of multiple fields of vertically stacked sediment waves, interbedded with units characterised by a chaotic seismic facies that accumulate mainly in the troughs of the sediment waves and can be tracked laterally to the adjacent canyons. According to their seismic facies, geometry, and internal architecture these chaotic units are interpreted as debrites. Seismic attributes extracted from different horizons indicate that the sediment waves are dominated by fine-grained sediment, while the debrites are probably associated with coarser-grained deposits. The debrites fill the troughs of the sediment waves, as well as the downstream portions of canyon thalweg, thus flattening the paleo-seafloor. The sediment waves are interpreted as cyclic steps formed by low-density turbidity currents flowing across the slope down to the basin floor, where the change in gradient favours the formation of hydraulic jumps and the transition from supercritical to subcritical flow conditions. A conceptual model for the sediment wave evolution was proposed for the study area, in the transitional environment on the lower slope, with low-density gravity flow deposits and high-density debris flow deposits alternatively accumulating on the major gravity flow conduits
Spectrums of investment in Doctor Who fandom
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Drawing upon a significant weight of empirical data, collected in the field, this thesis proposes a set of four spectrums of investment engaged in by cult media fans: the spectrum of financial investment; the spectrum of what is here termed 'participatory investment'; the spectrum of investment in the idea of textual authenticity; and the spectrum of multiple investments. The spectrum model allows the individual members of the research sample to be located within specific regions of each spectrum and correlations to be drawn between the distinct spectrums, in order for any patterns which emerge to be examined. The thesis also reviews a number of relevant theoretical concerns such as fan studies, ethnography and social psychology
Fan-surface dynamics and biogenic calcrete development: Interactions during ultimate phases of fan evolution in the semiarid SE Spain (Murcia)
No full textPleistocene alluvial fan surfaces of the Campo de Cartagena–Mar Menor Basin (Murcia, SE Spain) are capped by thick mature calcretes. Calcrete profiles consist mainly of six different horizons: prismatic, chalky, nodular, massive, laminar and coated-gravels. Petrographic study of the calcretes has shown the occurrence of features such as alveolar septal structures, calcified filaments, coated grains, spherulites, calcified root cells and calcispheres that indicate the biogenic origin of the calcretes, mainly induced by plant root related microbial activity. The calcretes studied were formed initially in the soil and represented the K horizon. Development of the calcrete profiles took place in six main stages and was driven by multiple phases of soil formation, erosion and reworking. The relationships between these processes caused the formation of different calcrete profiles in proximal and distal fan areas. In the distal areas, which are controlled by limited distal fan aggradation, episodic sediment input, buried previously developed calcretes and generated new space for calcrete growth by plants growing in the overlying unconsolidated materials. This allowed the renewal of calcrete formation and it led to the development of complex composite profiles which are thicker than in proximal areas, where surface stabilisation and/or dissection enabled calcrete reworking and brecciation. These processes of erosion, sedimentation, reworking and renewed calcrete formation initiated by vegetation were repeated through time. They explain the complex macro- and microstructures of these calcretes and indicate that calcrete development, even reaching mature stages, can start before the fan surface is completely abandoned, but it requires episodic sedimentation. Eventually, distal fan aggradation and continuous calcrete development throughout the entire fan surface, led to the ultimate fan surface induration, controlling subsequent landscape evolution. So, fan surface calcretes cannot be envisaged as simple top-surface carbonate accumulations, but as complex feedback systems in which pedogenic, biogenic and sedimentary processes interact in response to the evolving fan-surface dynamics during the terminal phases of fan development in semiarid environments.Dirección General de Investigación Científica y Técnica (España)Depto. de Mineralogía y PetrologíaDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
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