281 resultados para Dimension quantique


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Effective flocculation and dewatering of mineral processing streams containing clays are microstructure dependent in clay-water systems. Initial clay flocculation is crucial in the design and for the development of a new methodology of gas exploitation. Microstructural engineering of clay aggregates using covalent cations and Keggin macromolecules have been monitored using the new state of the art Transmission X-ray Microscope (TXM) with 60 nm tomography resolution installed in a Taiwanese synchrotron. The 3-D reconstructions from TXM images show complex aggregation structures in montmorillonite aqueous suspensions after treatment with Na+, Ca2+ and Al13 Keggin macromolecules. Na-montmorillonite displays elongated, parallel, well-orientated and closed-void cellular networks, 0.5–3 μm in diameter. After treatment by covalent cations, the coagulated structure displays much smaller, randomly orientated and openly connected cells, 300–600 nm in diameter. The average distances measured between montmorillonite sheets was around 450 nm, which is less than half of the cell dimension measured in Na-montmorillonite. The most dramatic structural changes were observed after treatment by Al13 Keggin; aggregates then became arranged in compacted domains of a 300 nm average diameter composed of thick face-to-face oriented sheets, which forms porous aggregates with larger intra-aggregate open and connected voids.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Goethite and Al-substituted goethite were synthesized from the reaction between ferric nitrate and/or aluminum nitrate and potassium hydroxide. XRF, XRD, TEM with EDS were used to characterize the chemical composition, phase and lattice parameters, and morphology of the synthesized products. The results show that d(020) decreases from 4.953 to 4.949 Å and the b dimension decreases from 9.951 Å to 9.906 Å when the aging time increases from 6 days to 42 days for 9.09 mol% Al-substituted goethite. A sample with 9.09 mol% Al substitution in Al-substituted goethite was prepared by a rapid co-precipitation method. In the sample, 13.45 mol%, 12.31 mol% and 5.85 mol% Al substitution with a crystal size of 163, 131, and 45 nm are observed as shown in the TEM images and EDS. The crystal size of goethite is positively related to the degree of Al substitution according to the TEM images and EDS results. Thus, this methodology is proved to be effective to distinguish the morphology of goethite and Al substituted goethite.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The status of entertainment as both a dimension of human culture, and a booming global industry is increasing. Given more recent consumer-centric definitions of entertainment, the entertainment consumer has grown in prominence and is now coming under closer scrutiny. However viewing entertainment consumers as always behaving in a similar fashion towards entertainment as to other products may be selling them short. For a start, entertainment consumers can exhibit a strong loyalty towards their favourite entertainment products that is the envy of the marketing world. Academic researchers and marketers who are keen to investigate entertainment consumers would benefit from a theoretical base from which to commence. This essay therefore, takes a consumer-oriented focus in defining entertainment and conceptualises a model of entertainment consumption. In approaching the study of entertainment one axiomatic question remains: how should we define it? Richard Dyer notes that, considering that the category of entertainment can include – by its own definition in the song ‘That’s entertainment!’ – everything from Hamlet and Oedipus Rex to ‘the clown with his pants falling down’ and ‘the lights on the lady in tights’, it doesn’t make much sense to try to define entertainment as being marked by particular textual features (as is done, for example, by Avrich, 2002). Dyer’s position is rather that ‘entertainment is not so much a category of things as an attitude towards things’ (Dyer, 1973: 9). He traces the modern conception of entertainment back to the writings of Molière. This writer defended the purpose of his plays against attacks from the church that they were not sufficiently edifying by insisting that, as entertainments he had no interest in edifying audiences – his ‘real purpose …was to provide people pleasure – and the definition of that was to be decided by “the people”’(Dyer, 1973: 9). In my own discipline of Marketing this approach has been embraced – Kaser and Oelkers, for example, define entertainment as ‘whatever people are willing to spend their money and spare time viewing’ (2008, 18). That is the approach taken in this paper, where I see entertainment as ‘consumer-driven culture’ (McKee and Collis, 2009) – a definition that is closely aligned with the marketing concept. Within a marketing framework I explore what the consumption of entertainment can tell us about the relationships between consumers and culture more generally. For entertainment offers an intriguing case study, and is often consumed in ways that challenge many of our assumptions about marketing and consumer behaviour.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This work investigates the accuracy and efficiency tradeoffs between centralized and collective (distributed) algorithms for (i) sampling, and (ii) n-way data analysis techniques in multidimensional stream data, such as Internet chatroom communications. Its contributions are threefold. First, we use the Kolmogorov-Smirnov goodness-of-fit test to show that statistical differences between real data obtained by collective sampling in time dimension from multiple servers and that of obtained from a single server are insignificant. Second, we show using the real data that collective data analysis of 3-way data arrays (users x keywords x time) known as high order tensors is more efficient than centralized algorithms with respect to both space and computational cost. Furthermore, we show that this gain is obtained without loss of accuracy. Third, we examine the sensitivity of collective constructions and analysis of high order data tensors to the choice of server selection and sampling window size. We construct 4-way tensors (users x keywords x time x servers) and analyze them to show the impact of server and window size selections on the results.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Food in schools is typically understood from a biomedical perspective. At practical, ideational and material levels, whether addressed pedagogically or bureaucratically, food in schools is generally considered from a natural sciences perspective. This perspective manifests as the bioenergetic principle of energy in versus energy out and appears in policy focused on issues such as obesity and physical activity. Despite the considerable literature on the sociology of food and eating, little is understood about food in schools from a sociological perspective. This oversight of one of the most fundamental requirements of the human condition--namely, food--should be of concern for educators. Investigating food through a political economy lens means understanding food in schools as part of broader economic, political, social and cultural conditions. Hence, a political economy of food and schooling is concerned with the formation of ideas about food relative to political, economic, and cultural ideologies in social practice. From a critical sociology study of food messages students receive in the primary school curriculum, this paper reports on some of the official food messages of an Australian state's education policy, as a case to highlight the current political economy of food in Australia. It examines the role of the corporate food industry in the formation of Australian food policy and how that policy created artefacts infused with competing messages. The paper highlights how food and nutrition policy moved from solely a health concern to incorporate an economic dimension and links that shift with the quality of food available in Queensland schools.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Graphene has promised many novel applications in nanoscale electronics and sustainable energy due to its novel electronic properties. Computational exploration of electronic functionality and how it varies with architecture and doping presently runs ahead of experimental synthesis yet provides insights into types of structures that may prove profitable for targeted experimental synthesis and characterization. We present here a summary of our understanding on the important aspects of dimension, band gap, defect, and interfacial engineering of graphene based on state-of-the-art ab initio approaches. Some most recent experimental achievements relevant for future theoretical exploration are also covered.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose: The measurement of broadband ultrasonic attenuation (BUA) in cancellous bone for the assessment of osteoporosis follows a parabolic-type dependence with bone volume fraction; having minima values corresponding to both entire bone and entire marrow. Langton has recently proposed that the primary BUA mechanism may be significant phase interference due to variations in propagation transit time through the test sample as detected over the phase-sensitive surface of the receive ultrasound transducer. This fundamentally simple concept assumes that the propagation of ultrasound through a complex solid : liquid composite sample such as cancellous bone may be considered by an array of parallel ‘sonic rays’. The transit time of each ray is defined by the proportion of bone and marrow propagated, being a minimum (tmin) solely through bone and a maximum (tmax) solely through marrow. A Transit Time Spectrum (TTS), ranging from tmin to tmax, may be defined describing the proportion of sonic rays having a particular transit time, effectively describing lateral inhomogeneity of transit time over the surface of the receive ultrasound transducer. Phase interference may result from interaction of ‘sonic rays’ of differing transit times. The aim of this study was to test the hypothesis that there is a dependence of phase interference upon the lateral inhomogenity of transit time by comparing experimental measurements and computer simulation predictions of ultrasound propagation through a range of relatively simplistic solid:liquid models exhibiting a range of lateral inhomogeneities. Methods: A range of test models was manufactured using acrylic and water as surrogates for bone and marrow respectively. The models varied in thickness in one dimension normal to the direction of propagation, hence exhibiting a range of transit time lateral inhomogeneities, ranging from minimal (single transit time) to maximal (wedge; ultimately the limiting case where each sonic ray has a unique transit time). For the experimental component of the study, two unfocused 1 MHz ¾” broadband diameter transducers were utilized in transmission mode; ultrasound signals were recorded for each of the models. The computer simulation was performed with Matlab, where the transit time and relative amplitude of each sonic ray was calculated. The transit time for each sonic ray was defined as the sum of transit times through acrylic and water components. The relative amplitude considered the reception area for each sonic ray along with absorption in the acrylic. To replicate phase-sensitive detection, all sonic rays were summed and the output signal plotted in comparison with the experimentally derived output signal. Results: From qualtitative and quantitative comparison of the experimental and computer simulation results, there is an extremely high degree of agreement of 94.2% to 99.0% between the two approaches, supporting the concept that propagation of an ultrasound wave, for the models considered, may be approximated by a parallel sonic ray model where the transit time of each ray is defined by the proportion of ‘bone’ and ‘marrow’. Conclusions: This combined experimental and computer simulation study has successfully demonstrated that lateral inhomogeneity of transit time has significant potential for phase interference to occur if a phase-sensitive ultrasound receive transducer is implemented as in most commercial ultrasound bone analysis devices.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The framework by which organizations are governed has been changed. A reason for this change is related with the force of stakeholders that compel the political power and the business society to review the ways in which companies are governed. Stakeholder thinking has gradually put this change at the center of research into business and society relations. Based on the stakeholder thinking, the corporate regulation framework has extended a new dimension in the business and society interface. This article assesses these issues.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The emerging ‘responsibility to protect’ (R2P) principle presents a significant challenge to the BRICS (Brazil, Russia, India, China and South Africa) states’ traditional emphasis on a strict Westphalian understanding of state sovereignty and non-interference in domestic affairs. Despite formally endorsing R2P at the 2005 World Summit, each of the BRICS has, to varying degrees, retained misgivings about coercive measures under the doctrine’s third pillar. This paper examines how these rising powers engaged with R2P during the 2011–2012 Libyan and Syrian civilian protection crises. The central finding is that although all five states expressed similar concerns over NATO’s military campaign in Libya, they have been unable to maintain a common BRICS position on R2P in Syria. Instead, the BRICS have splintered into two sub-groups. The first, consisting of Russia and China, remains steadfastly opposed to any coercive measures against Syria. The second, comprising the democratic IBSA states (India, Brazil and South Africa) has displayed softer, more flexible stances towards proposed civilian protection measures in Syria, although these three states also remain cautious about the implementation of R2P’s coercive dimension. This paper identifies a number of factors which help to explain this split, arguing that the failure to maintain a cohesive BRICS position on R2P is unsurprising given the many internal differences and diverging national interests between the BRICS members. Overall, the BRICS’ ongoing resistance to intervention is unlikely to disappear quickly, indicating that further attempts to operationalize R2P’s third pillar may prove difficult.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Monitoring foodservice satisfaction is a risk management strategy for malnutrition in the acute care sector, as low satisfaction may be associated with poor intake. This study aimed to investigate the relationship between age and foodservice satisfaction in the private acute care setting. Patient satisfaction was assessed using a validated tool, the Acute Care Hospital Foodservice Patient Satisfaction Questionnaire for data collected 2008–2010 (n = 779) at a private hospital, Brisbane. Age was grouped into three categories; <50 years, 51–70 years and >70 years. Fisher’s exact test assessed independence of categorical responses and age group; ANOVA or Kruskal–Wallis test was used for continuous variables. Dichotomised responses were analysed using logistic regression and odds ratios (95% confidence interval, p < 0.05). Overall foodservice satisfaction (5 point scale) was high (≥4 out of 5) and was independent of age group (p = 0.377). There was an increasing trend with age in mean satisfaction scores for individual dimensions of foodservice; food quality (p < 0.001), meal service quality (p < 0.001), staff service issues (p < 0.001) and physical environment (p < 0.001). A preference for being able to choose different sized meals (59.8% > 70 years vs 40.6% ≤50 years; p < 0.001) and response to ‘the foods are just the right temperature’ (55.3% >70 years vs 35.9% ≤50 years; p < 0.001) was dependent on age. For the food quality dimension, based on dichotomised responses (satisfied or not), the odds of satisfaction was higher for >70 years (OR = 5.0, 95% CI: 1.8–13.8; <50 years referent). These results suggest that dimensions of foodservice satisfaction are associated with age and can assist foodservices to meet varying generational expectations of clients.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In a recent paper, Gordon, Muratov, and Shvartsman studied a partial differential equation (PDE) model describing radially symmetric diffusion and degradation in two and three dimensions. They paid particular attention to the local accumulation time (LAT), also known in the literature as the mean action time, which is a spatially dependent timescale that can be used to provide an estimate of the time required for the transient solution to effectively reach steady state. They presented exact results for three-dimensional applications and gave approximate results for the two-dimensional analogue. Here we make two generalizations of Gordon, Muratov, and Shvartsman’s work: (i) we present an exact expression for the LAT in any dimension and (ii) we present an exact expression for the variance of the distribution. The variance provides useful information regarding the spread about the mean that is not captured by the LAT. We conclude by describing further extensions of the model that were not considered by Gordon,Muratov, and Shvartsman. We have found that exact expressions for the LAT can also be derived for these important extensions...

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Literacy studies have begun to examine the spatial dimension of literacy practices in a way that foregrounds space, and that considers space as constitutive to human relations and practices. This chapter provides an introduction to spatial literacy research, providing a guide to key theorists, themes, and studies that have shaped historical and new developments in spatial approaches to literacy practice and pedagogy. It begins by reconceptualising socio-spatial approaches to literacy research and defines terms. Intersections with related social theories are examined, with an emphasis on critical approaches and the politics of space. It clarifies the relationship between socio-spatial and socio-cultural paradigms, revisiting the spatial in seminal socio-cultural research. It covers new ground,including networks, flows, and deterritorialisation of literacy practice. The chapter concludes with challenges and recommendations for future language research and educational practice.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Process-aware information systems (PAISs) can be configured using a reference process model, which is typically obtained via expert interviews. Over time, however, contextual factors and system requirements may cause the operational process to start deviating from this reference model. While a reference model should ideally be updated to remain aligned with such changes, this is a costly and often neglected activity. We present a new process mining technique that automatically improves the reference model on the basis of the observed behavior as recorded in the event logs of a PAIS. We discuss how to balance the four basic quality dimensions for process mining (fitness, precision, simplicity and generalization) and a new dimension, namely the structural similarity between the reference model and the discovered model. We demonstrate the applicability of this technique using a real-life scenario from a Dutch municipality.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The nature and characteristics of how learners learn today are changing. As technology use in learning and teaching continues to grow, its integration to facilitate deep learning and critical thinking becomes a primary consideration. The implications for learner use, implementation strategies, design of integration frameworks and evaluation of their effectiveness in learning environments cannot be overlooked. This study specifically looked at the impact that technology-enhanced learning environments have on different learners’ critical thinking in relation to eductive ability, technological self-efficacy, and approaches to learning and motivation in collaborative groups. These were explored within an instructional design framework called CoLeCTTE (collaborative learning and critical thinking in technology-enhanced environments) which was proposed, revised and used across three cases. The field of investigation was restricted to three key questions: 1) Do learner skill bases (learning approach and eductive ability) influence critical thinking within the proposed CoLeCTTE framework? If so, how?; 2) Do learning technologies influence the facilitation of deep learning and critical thinking within the proposed CoLeCTTE framework? If so, how?; and 3) How might learning be designed to facilitate the acquisition of deep learning and critical thinking within a technology-enabled collaborative environment? The rationale, assumptions and method of research for using a mixed method and naturalistic case study approach are discussed; and three cases are explored and analysed. The study was conducted at the tertiary level (undergraduate and postgraduate) where participants were engaged in critical technical discourse within their own disciplines. Group behaviour was observed and coded, attributes or skill bases were measured, and participants interviewed to acquire deeper insights into their experiences. A progressive case study approach was used, allowing case investigation to be implemented in a "ladder-like" manner. Cases 1 and 2 used the proposed CoLeCTTE framework with more in-depth analysis conducted for Case 2 resulting in a revision of the CoLeCTTE framework. Case 3 used the revised CoLeCTTE framework and in-depth analysis was conducted. The findings led to the final version of the framework. In Cases 1, 2 and 3, content analysis of group work was conducted to determine critical thinking performance. Thus, the researcher used three small groups where learner skill bases of eductive ability, technological self-efficacy, and approaches to learning and motivation were measured. Cases 2 and 3 participants were interviewed and observations provided more in-depth analysis. The main outcome of this study is analysis of the nature of critical thinking within collaborative groups and technology-enhanced environments positioned in a theoretical instructional design framework called CoLeCTTE. The findings of the study revealed the importance of the Achieving Motive dimension of a student’s learning approach and how direct intervention and strategies can positively influence critical thinking performance. The findings also identified factors that can adversely affect critical thinking performance and include poor learning skills, frustration, stress and poor self-confidence, prioritisations over learning; and inadequate appropriation of group role and tasks. These findings are set out as instructional design guidelines for the judicious integration of learning technologies into learning and teaching practice for higher education that will support deep learning and critical thinking in collaborative groups. These guidelines are presented in two key areas: technology and tools; and activity design, monitoring, control and feedback.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The semantic of the terms “sustainable development” and “corporate social responsibility” have changed over time to a point where these concepts have become two interrelated processes for ensuring the far-reaching development of society. Their convergence has given dimension to the environmental and corporate regulation mechanisms in strong economies. This article deals with the question of how the ethos of this convergence could be incorporated into the self-regulation of businesses in weak economies where nonlegal drivers are either inadequate or inefficient. It proposes that the policies for this incorporation should be based on the precepts of meta-regulation that have the potential to hold force majeure, economic incentives, and assistance-related strategies to reach an objective from the perspective of weak economies.