974 resultados para reflection process
Resumo:
For the past decades reflection has been the buzzword of adult and higher education. Reflection is facilitated in many practices and there is abundant research on the issue. Despite the popularity of the concept, the reasons why bringing about reflection in educational practices is difficult remain unclear. The prevailing theories inform of the process in its ideal form. However, to a great extent, they fail to offer conceptual tools for understanding and working with the actualities of reflection. The aim of the doctoral thesis was to explore the challenges and prerequisites of reflection in order to theorize the nature of reflection. By the term reflection it is here referred to becoming aware of and questioning the assumptions that orient our thinking, feelings and actions. The doctoral thesis consists of five studies that approach these questions from different viewpoints and within different contexts. The methods involve both a philosophical and an empirical approach. This multifaceted approach embodies the aim of both gaining a more thorough grasp of the phenomenon and to develop the methodology of researching reflection. The theory building is based on conceptual analysis and rational reconstruction (see Davia 1998; Habermas 1979; Rorty1984) of Mezirow s (1981; 1991; 2000; 2009) theory of transformative learning. In order to explore the aspects which, based on the analysis, appeared insufficiently considered within Mezirow s theory, Damasio s (1994; 1999; 2003; 2010) theory on emotions and consciousness as well as Clausewitz s (1985) view on friction are used as complementary theories. Empirical analyses are used in dialogue with the theoretical, in order to challenge and refine the emerging theorization. Reflection is examined in three different contexts; regarding university teachers pedagogical growth, involuntarily childless women recovering from a life-event crisis, and soldiers preparing to act in chaotic situations of the battlefield as well as recovering from it. The choice of these contexts is based on Mezirow s notion of disorienting dilemma as a trigger for reflection. This notion indicates that reflection may more naturally emerge in association to life-event crises or other cumulative sets of instances, which bring our worldview and beliefs under question. Nevertheless, reflection is often being promoted in educational contexts in which the trigger conditions may not readily prevail. These contextual issues as well as the differences between the facilitated and non-facilitated contexts have not, however, been considered in detail within the research on reflection (or transformative learning). The doctoral thesis offers a new perspective into reflection which, as a further development on Mezirow s transformative learning theory, theorizes the nature of reflection. The developed theory explicates the prerequisites and challenges to reflection. The theory suggests that the challenges of reflection are fundamentally connected to the way the biological life-support system affects our thinking through emotions. While depicting the mechanisms that function as a counterforce to reflection, the developed theory also opens a perspective for considering possibilities for carrying out reflection, and suggests ways to locate and deal with the assumptions to be reflected on. The basic dynamic of the challenges to reflection was explicated by conceptually bridging the gap between Mezirow s and Damasio s theories, through exploring the connections between the meaning perspective and the biological functions of emotions. The concepts of comfort zone and edge-emotions were formed so as to depict the emotional orientation of our thinking, as part of the explanation of the nature of reflection.
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Resonant sound absorbers are used widely as anechoic coatings in underwater applications. In this paper a finite element scheme based on the Galerkin technique is used to analyze the reflection characteristics of the resonant absorber when insonified by a normal incidence plane wave. A waveguide theory coupled with an impedance matching condition in the fluid is used to model the problem. It is shown in this paper that the fluid medium encompassing the absorber can be modeled as an elastic medium with equivalent Lamé constants. Quarter symmetry conditions within the periodic unit cell are exploited. The finite element results are compared with analytical results, and with results published elsewhere in the literature. It is shown in the process that meshing of the fluid domain can be obviated if the transmission coefficients or reflection coefficients only are desired as is often the case. Finally, some design curves for thin resonant absorbers with water closure are presented in this paper.
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In this paper the Deflagration to Detonation Transition (DDT) process of gaseous H-2-O-2 mixture and Mach reflection of gaseous detonation wave on a wedge have been conducted experimentally. The cellular pattern of DDT process and Mach reflection were obtained from experiments with wedge angle theta = 10(0) similar to 40(0) and initial pressure of gaseous mixture 16kPa similar to 26.7kPa. The 2-D numerical simulations of DDT process and Mach reflection of detonation wave were performed by using the simplified ZND model and improved space-time conservation element and solution element (CE/SE) method. The numerical cellular structures were compared with the cellular patterns of soot track. Compared results were shown that it is satisfactory. The characteristic comparisons on Mach reflection of air shock wave and detonation wave were carried also out and their differences were given.
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Seismic reflection methods have been extensively used to probe the Earth's crust and suggest the nature of its formative processes. The analysis of multi-offset seismic reflection data extends the technique from a reconnaissance method to a powerful scientific tool that can be applied to test specific hypotheses. The treatment of reflections at multiple offsets becomes tractable if the assumptions of high-frequency rays are valid for the problem being considered. Their validity can be tested by applying the methods of analysis to full wave synthetics.
Three studies illustrate the application of these principles to investigations of the nature of the crust in southern California. A survey shot by the COCORP consortium in 1977 across the San Andreas fault near Parkfield revealed events in the record sections whose arrival time decreased with offset. The reflectors generating these events are imaged using a multi-offset three-dimensional Kirchhoff migration. Migrations of full wave acoustic synthetics having the same limitations in geometric coverage as the field survey demonstrate the utility of this back projection process for imaging. The migrated depth sections show the locations of the major physical boundaries of the San Andreas fault zone. The zone is bounded on the southwest by a near-vertical fault juxtaposing a Tertiary sedimentary section against uplifted crystalline rocks of the fault zone block. On the northeast, the fault zone is bounded by a fault dipping into the San Andreas, which includes slices of serpentinized ultramafics, intersecting it at 3 km depth. These interpretations can be made despite complications introduced by lateral heterogeneities.
In 1985 the Calcrust consortium designed a survey in the eastern Mojave desert to image structures in both the shallow and the deep crust. Preliminary field experiments showed that the major geophysical acquisition problem to be solved was the poor penetration of seismic energy through a low-velocity surface layer. Its effects could be mitigated through special acquisition and processing techniques. Data obtained from industry showed that quality data could be obtained from areas having a deeper, older sedimentary cover, causing a re-definition of the geologic objectives. Long offset stationary arrays were designed to provide reversed, wider angle coverage of the deep crust over parts of the survey. The preliminary field tests and constant monitoring of data quality and parameter adjustment allowed 108 km of excellent crustal data to be obtained.
This dataset, along with two others from the central and western Mojave, was used to constrain rock properties and the physical condition of the crust. The multi-offset analysis proceeded in two steps. First, an increase in reflection peak frequency with offset is indicative of a thinly layered reflector. The thickness and velocity contrast of the layering can be calculated from the spectral dispersion, to discriminate between structures resulting from broad scale or local effects. Second, the amplitude effects at different offsets of P-P scattering from weak elastic heterogeneities indicate whether the signs of the changes in density, rigidity, and Lame's parameter at the reflector agree or are opposed. The effects of reflection generation and propagation in a heterogeneous, anisotropic crust were contained by the design of the experiment and the simplicity of the observed amplitude and frequency trends. Multi-offset spectra and amplitude trend stacks of the three Mojave Desert datasets suggest that the most reflective structures in the middle crust are strong Poisson's ratio (σ) contrasts. Porous zones or the juxtaposition of units of mutually distant origin are indicated. Heterogeneities in σ increase towards the top of a basal crustal zone at ~22 km depth. The transition to the basal zone and to the mantle include increases in σ. The Moho itself includes ~400 m layering having a velocity higher than that of the uppermost mantle. The Moho maintains the same configuration across the Mojave despite 5 km of crustal thinning near the Colorado River. This indicates that Miocene extension there either thinned just the basal zone, or that the basal zone developed regionally after the extensional event.
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The high reflection (HR) mirror composed of dielectric stacks with excellent spectrum characteristics and high damage resistant ability is critical for fabricating multilayer dielectric (MLD) grating for pulse compressor. The selection of the SiO2 material as the top layer of the HR mirror for grating fabrication is beneficial for improving the laser-induced damage threshold of MLD grating as well as minimizing the standing-wave effect in the photoresist during the exposure process. Based on an (HLL) H-9 design comprising quarter-waves of HfO2 ( H) and half-waves of SiO2 ( L), we obtain an optimal design of the HR mirror for MLD grating, the SiO2 top layer of which is optimized with a merit function including both the diffraction efficiency of the MLD grating and the electric field enhancement in the grating. Dependence of the performance of the MLD grating on the fabrication error of the dielectric mirror is analysed in detail. The HR mirror is also fabricated by E-beam evaporation, which shows good spectral characteristics at the exposure wavelength of 413 nm and at the operation wavelength of 1053 nm and an average damage threshold of 10 J cm(-2) for a 12 ns pulse.
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An accurate description of atomic interactions, such as that provided by first principles quantum mechanics, is fundamental to realistic prediction of the properties that govern plasticity, fracture or crack propagation in metals. However, the computational complexity associated with modern schemes explicitly based on quantum mechanics limits their applications to systems of a few hundreds of atoms at most. This thesis investigates the application of the Gaussian Approximation Potential (GAP) scheme to atomistic modelling of tungsten - a bcc transition metal which exhibits a brittle-to-ductile transition and whose plasticity behaviour is controlled by the properties of $\frac{1}{2} \langle 111 \rangle$ screw dislocations. We apply Gaussian process regression to interpolate the quantum-mechanical (QM) potential energy surface from a set of points in atomic configuration space. Our training data is based on QM information that is computed directly using density functional theory (DFT). To perform the fitting, we represent atomic environments using a set of rotationally, permutationally and reflection invariant parameters which act as the independent variables in our equations of non-parametric, non-linear regression. We develop a protocol for generating GAP models capable of describing lattice defects in metals by building a series of interatomic potentials for tungsten. We then demonstrate that a GAP potential based on a Smooth Overlap of Atomic Positions (SOAP) covariance function provides a description of the $\frac{1}{2} \langle 111 \rangle$ screw dislocation that is in agreement with the DFT model. We use this potential to simulate the mobility of $\frac{1}{2} \langle 111 \rangle$ screw dislocations by computing the Peierls barrier and model dislocation-vacancy interactions to QM accuracy in a system containing more than 100,000 atoms.
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The evolution of carbonization process on Si as a function of ion dose has been carried out by mass-selected ion-beam deposition technique. 3C-SiC layer has been obtained at low ion dose, which has been observed by reflection high energy electron diffraction and X-ray photoelectron spectroscopy (XPS). The chemical states of Si and carbon have also been examined as a function of ion dose by XPS. Carbon enrichment was found regardless of the used ion dose here, which may be due to the high deposition rate. The formation mechanism of SiC has also been discussed based on the subplantation process. The work will also provide further understanding of the ion-bombardment effect. (C) 2001 Published by Elsevier Science B.V.
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Zeolite Y has been used as the host to generate CdS nanoclusters. The location of CdS nanoclusters inside zeolite hosts was confirmed by the blue-shifted reflection absorption spectra with respect to that of bulk CdS materials. But which kind of cage inside zeolite Y, sodalite cage or supercage, was preferred for the CdS clusters remained unclear. In this paper, we conducted positron annihilation spectroscopy (PAS) measurements for the first time on a series of CdS/Y zeolite samples and concluded that CdS clusters were not located in supercages but in smaller sodalite cages. The stability of CdS clusters inside the sodalite units was due to the coordination of Cd atoms with the framework oxygen atoms of the double six-ring windows. Moreover, PAS revealed some important information of surface states existing on the interfacial layers between CdS clusters and zeolite Y. (C) 2001 Elsevier Science B,V, All rights reserved.
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A novel inorganic-organic hybrid hydrophobic anti-reflection silica film used for laser crystal was obtained by sol-gel process. The film consisted of silica sols mixed with a small amount of polymethyl methacrylate (PMMA) or polystyrene (PS). The optical transparency, hydrophobic property and surface morphology of the film were characterized by UV-VIS-NIR spectrophotometer; contact angle instrument and Scanning Electron Microscopy (SEM), respectively. The results showed that the anti-reflection coating had good hydrophobility and optical transparency from 400 nm to 1200 nm. The contact angle reached to 130-140 degrees. SEM images indicated the hydrophobic films modified with PMMA or PS had compact structure compared to the pure silica sol film. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
The final structure of molten syndiotactic polypropylene (sPP) sheared under different conditions was investigated by synchrotron small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (WAXD) techniques to elucidate the shear effects on sPP crystalline structure. The results obtained from the WAXD show that there is no variation on crystalline form but a little difference on the orientation of the 200 reflection. The SAXS data indicate that the lamellar thickness and long period have not been affected by shear but the lamellar orientation is dependent on shear. The experimental data of sPP crystallization from sheared melt may indicate a mesophase structure that is crucial to the shear effects on the final polymer multiscale crystalline structures.
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This article contributes to the debate on what form of preparation and support can enhance the intercultural student experience during the Year Abroad. It presents a credit-bearing and multi-modal module at a UK university designed to both prepare students prior to departure through a series of workshops and activities on an e-portfolio and help them engage in meta-reflection on intercultural issues during their stay. The presentation of the curricular components of the course and instances extracted from student blogs are contextualised within theoretical considerations on intercultural education and a holistic approach to student development. The longitudinal evolution of the module is presented in the context of an iterative approach leading to a cycle of revisions and amendments. With its pragmatic stance this article aims to address one of the concerns recently expressed about intercultural education, namely that although intercultural theories are suitably incorporated in the latest thinking on communicative competence, there is a lack of evidence-based practice.
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Providing a method of transparent communication and interoperation between distributed software is a requirement for many organisations and several standard and non-standard infrastructures exist for this purpose. Component models do more than just provide a plumbing mechanism for distributed applications, they provide a more controlled interoperation between components. There are very few component models however that have support for advanced dynamic reconfigurability. This paper describes a component model which provides controlled and constrained transparent communication and inter-operation between components in the form of a hierarchical component model. At the same time, the model contains support for advanced run-time reconfigurability of components. The process and benefits of designing a system using the presented model are discussed. A way in which reflective techniques and component frameworks can work together to produce dynamic adaptable systems is explained.
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This paper examines the DC power requirements of PIN diodes which, with suitable applied DC bias, have the potential to reflect or to permit transmission of millimetre wave energy through them by the process of inducing a semiconductor plasma layer in the i-region. The study is conducted using device level simulation of SOI and bulk PIN diodes and reflection modelling based on the Drude conduction model. We examined five diode lengths (60–140 µm) and seven diode thicknesses (4–100 µm). Simulation output for the diodes of varying thicknesses was subsequently used in reflection modelling to assess their performance for 100 GHz operation. It is shown that substantially high DC input power is required in order to induce near total reflection in SOI PIN diodes at 100 GHz. Thinner devices consume less DC power, but reflect less incident radiation for given input power. SOI diodes are shown to have improved carrier confinement compared with bulk diodes.
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Within the ever-changing arenas of architectural design and education, the core element of architectural education remains: that of the design process. The consideration of how to design in addition to what to design presents architectural educators with that most constant and demanding challenge of how do we best teach the design process?
This challenge is arguably most acute at a student's early stages of their architectural education. In their first years in architecture, students will commonly concentrate on the end product rather than the process. This is, in many ways, understandable. A great deal of time, money and effort go into their final presentations. They believe that it is what is on the wall that is going to be assessed. Armed with new computer skills, they want to produce eye-catching graphics that are often no more than a celebration of a CAD package. In an era of increasing speed, immediacy of information and powerful advertising it is unsurprising that students want to race quickly to presenting an end-product.
Recognising that trend, new teaching methods and models were introduced into the second year undergraduate studio over the past two years at Queen's University Belfast, aimed at promoting student self-reflection and making the design process more relevant to the students. This paper will first generate a critical discussion on the difficulties associated with the design process before outlining some of the methods employed to help promote the following; an understanding of concept, personalisation of the design process for the individual student; adding realism and value to the design process and finally, getting he students to play to their strengths in illustrating their design process like an element of product. Frameworks, examples, outcomes and student feedback will all be presented to help illustrate the effectiveness of the new strategies employed in making the design process firstly, more relevant and therefore secondly, of greater value, to the architecture student.
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Over the last 5–10 years, marine spatial planning (MSP) has emerged as a new management regime for national and international waters and has already attracted a substantial body of multi-disciplinary research on its goals and policy processes. This paper argues that this literature has generally lacked deeper reflexive engagement with the emerging system of governance for our seas that has meant that many of MSP’s core concepts, assumptions and institutional arrangements have not been subject rigorous intellectual debate. In an attempt to initiate such an approach, this article explores the relationship between MSP and its land-based cousin, terrestrial spatial planning (TSP). While it is recognized that there are inherent limitations to a comparison of these two systems, it is argued that the tradition of social science debate over the purpose and processes of TSP can be used as a useful stimulus for a more rigorous reflection of such issues as they relate to MSP. The article therefore explores some of the parallels between MSP and TSP and then discusses some of the key intellectual traditions that have shaped TSP and the implications these may have for future marine planning practice. The article concludes with a number of potentially useful new avenues that may form the basis of a critical research agenda for MSP.