60419 research outputs found
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Cyclic stress–strain rate-dependent response of rubberised concrete
No full textThis paper presents an experimental investigation into the constitutive response of rubberised concrete materials under monotonic and cyclic compression. After describing the test specimens and experimental arrangement, a detailed account of the stress–strain response of rubberised concrete materials, as well as their reference high strength conventional concrete, is given. The volumetric rubber content is varied between 0 and 40% of both fine and coarse aggregates. Both monotonic and cyclic loading conditions are considered for comparison, and three strain rate levels, simulating static, moderate and severe seismic action, are examined. The increase in rubber content is shown to have a detrimental effect on the stiffness and strength, as expected. However, with the increase in rubber content, rubberised concrete materials are shown to exhibit improved compressive recovery under cyclic loading, coupled with a higher energy accumulation rate, enhanced inter-cycle stability and lower inter-cycle degradation. It is also shown that the increase in strain rate, from static to severe seismic, leads to a notable increase in the stiffness and strength, with these enhancements becoming less significant with the increase in rubber content. Based on the results and observations, expressions for determining the unloading stiffness and residual strain, as a function of rubber content and strain rate, are proposed within the ranges considered. The suggested relationships enable the characterisation of rubberised concrete materials within widely used cyclic constitutive models
Students’ views about the purpose of higher education: a comparative analysis of six European countries
No full textAcross Europe, assumptions are often made within the academic literature and by some social commentators that students have come to understand the purpose of higher education (HE) in increasingly instrumental terms. This is often linked to processes of marketisation and neo-liberalisation across the Global North, in which the value of HE has come to be associated with economic reward and labour market participation and measured through a relatively narrow range of metrics. It is also associated with the establishment, in 2010, of the European Higher Education Area, which is argued to have brought about the refiguration of European universities around an Anglo-American model. Scholars have contended that students have become consumer-like in their behaviour and preoccupied by labour market outcomes rather than processes of learning and knowledge generation. Often, however, such claims are made on the basis of limited empirical evidence, or a focus on policies and structures rather than the perspectives of students themselves. In contrast, this paper draws on a series of 54 focus groups with 295 students conducted in six European countries (Denmark, England, Germany, Ireland, Poland and Spain). It shows how understandings of the purpose of HE are more nuanced than much of the extant literature suggests and vary, at least to some extent, by both nation-state and higher education institution. Alongside viewing the purpose of HE as preparing them for the labour market, students emphasised the importance of tertiary-level study for personal growth and enrichment, and societal development and progress. These findings have implications for policy and practice. In particular, the broader purposes of HE, as articulated by the students in this study, should be given greater recognition by policymakers, those teaching in HE, and the wider public instead of, as is often the case, positioning students as consumers, interested in only economic gain
An adaptive reference vector guided evolutionary algorithm using growing neural gas for many-objective optimization of irregular problems
No full textMost reference vector based decomposition algorithms
for solving multi-objective optimization problems may not
be well suited for solving problems with irregular Pareto fronts
because the distribution of predefined reference vectors may not
match well with the distribution of the Pareto optimal solutions.
Thus, adaptation of the reference vectors is an intuitive way for
decomposition based algorithms to deal with irregular Pareto
fronts. However, most existing methods frequently change the
reference vectors based on the activeness of the reference vectors
within specific generations, slowing down the convergence of the
search process. To address this issue, we propose a new method to
learn the distribution of the reference vectors using the growing
neural gas network to achieve automatic yet stable adaptation. To
this end, an improved growing neural gas is designed for learning
the topology of the Pareto fronts with the solutions generated
during a period of the search process as the training data. We
use the individuals in the current population as well as those in
previous generations to train the growing neural gas to strike
a balance between exploration and exploitation. Comparative
studies conducted on popular benchmark problems and a realworld
hybrid vehicle controller design problem with complex and
irregular Pareto fronts show that the proposed method is very
competitive
Audiences’ Communicative Agency in a Datafied Age: Interpretative, Relational and Increasingly Prospective
No full textThis article develops a conceptualization of audience agency in the face of datafication. We consider how people, as audiences and users of media and technologies, face transforming communicative conditions, and how these conditions challenge the power potentials of audiences in processes of communication—that is, their communicative agency. To develop our conceptualization, we unpack the concept of audiences’ communicative agency by examining its foundations in communication scholarship, in reception theory and sociology, arguing that agency is understood as interpretative and relational, and applied to make important normative assessments. We further draw on emerging scholarship on encounters with data in the everyday to discuss how audience agency is now challenged by datafication, arguing that communicative agency is increasingly prospective in a datafied age. Thereby, we provide a theoretical conceptualization for further analysis of audiences in transforming communicative conditions
Influence of the Active Phase (Fe, Ni, and Ni–Fe) of Mixed Oxides in CWAO of Crystal Violet
No full textThe catalytic oxidation of aqueous crystal violet (CV) solutions was investigated using Ni and Fe catalysts supported over Mg–Al oxides synthesized by the autocombustion method. The influence of temperature, loading, and selectivity were studied in the catalytic wet air oxidation (CWAO) of CV. The kind of metal had an important contribution in the redox process as significant differences were observed between Fe, Ni, and their mixtures. The catalysts with only Fe as active phase were more efficient for the oxidation of CV under normal conditions (T = 25 °C and atmospheric pressure) compared to those containing Ni, revealing the influence of the transition metal on catalytic properties. It was found that iron-containing materials displayed enhanced textural properties. The synthesis of Fe/MgAl catalysts by the autocombustion method led to solids with excellent catalytic behavior, 100% CV degradation in eight hours of reaction, 68% selectivity to CO₂, and significant reduction of chemical oxygen demand (COD)
Slipping Through the Cracks in e-Lexicography
No full textDespite the remarkable advances made in recent years to facilitate the lexicographer’s work of interpreting and synthesizing the complexity of language uncovered by corpora, an uncritical use of cutting-edge corpus tools and resources can instill a false sense of assurance. In this paper, authentic examples pertaining to wordlist use, collocation research and example selection that arose when compiling a real-world lexical database are discussed through the lens of problems that can easily slip through the cracks in e-lexicography. In doing so, we emphasize the importance of solid training and sound lexicographic judgment when using corpora, corpus tools and corpus-derived resources, and provide an opportunity to reflect on how e-lexicography can be further refined in the future
Multiple hazard fragility analysis for granular highway embankments: moisture ingress and scour
No full textFragility functions express the probability that an asset exceeds some serviceability or limit state for a given level of environmental perturbation or other loadings, to which the asset is subjected. They are important components in the quantitative risk analysis of infrastructure exposed to natural hazards and they have typically been derived for structural assets. It is relatively difficult to derive fragility functions for geotechnical assets, such as highway or railway slopes and embankments, due to their inherent heterogeneity. In this paper, a generic granular highway embankment is modelled using the finite element method, considering various groundwater profiles and scour depths at the toe to quantify the deformation of the road surface. A probabilistic assessment of the magnitude of deformation and the groundwater level and scour depth is undertaken to derive fragility functions for the prediction of damage to assets exposed to these multiple hazards. The process of fragility function derivation is explained, uncertainty values are derived, and various regression methods are undertaken. This study is a first attempt to provide a basis for the prediction of slope deformation, and hence of damage, due to moisture ingress and scour, which can be aggravated by climate change. This can be used for the assessment of existing assets, and the design of new ones in the pursuit of more resilient transport networks, as well as for other assets such as levees, dams and other similar earthworks, with some limitations
Developing a LTE Localization Framework using Real Network Data towards RAN Optimization through Context Knowledge
No full textThe exponential growth of the network elements and
data traffic exchange in the last few years elevated the need
of network providers for optimized and cost-efficient solutions
regarding network management and monitorization. Solutions
such as drive-tests (DTs) are becoming extremely expensive with
the vast extension and complexity of nowadays mobile networks.
Therefore, this paper provides a solution for optimized networkcontext
knowledge acquisition, towards the self-organizing networks
(SONs) concept. The presented framework incorporates
an entire scheme for network Traces processing and positioning,
based on network measurements and fingerprinting techniques.
This framework enables a series of different use cases for network
management and optimization, with real-time data processing
capabilities within the network Traces collection interval (15
minutes), and achieving a median positioning error of 90 m
The effect of thermal treatment on the properties of expanded polystyrene
No full textExpanded polystyrene (EPS) is a commonly used polymer in the packaging industry and for the thermal insulation of buildings. It has poor mechanical properties which limit its application in some areas. A heat treatment was carried out on a sample of EPS, in order to improve its mechanical properties. The treatment consists of operations that combine the heating and cooling of the material. It is executed to improve the characteristics of the treated polymer and make it more favourable for use in new applications. In the case of EPS, this process changes the behaviour of the polymer in a beneficial manner and maximizes its density and hardness. Indeed, the treated version shows interesting mechanical, tribological and hygroscopic properties. This improvement was obtained mainly due to the morphological modification of the structure of EPS. Indeed, heat treatment leads to the creation of a polystyrene crust which covers every EPS bead. This crust protects the cell structure of each bead against stretching and supports most of the load applied to the treated version of EPS. Thus, the treated EPS can be used not only for packaging and thermal insulation but also for more structural applications
Toward a nuanced and targeted forest and peat fires prevention policy: Insight from psychology
No full textIndonesian forest and peat fires have become global concern. Not only the fires have caused regional environmental and humanitarian crises, they also have exacerbated global climate change. Radical and rapid land use change couple with irresponsible practice of clearing land through burning are key contributing factors. In response, the Indonesian government issued a strict ban on the practice. While this policy outcome continues to shortfall, it implicates traditional farmers whose subsistence depends on such a practice. This reality necessitates effort to develop a more nuanced and targeted intervention. Thus, this study examines individual's intention to clear land using fire. We surveyed 151 Indonesian traditional farmers based on the Theory of Planned Behavior (TPB), the Norm Activation Model (NAM) and past behavior. We identified the TPB, which is augmented by the past behavior and awareness of consequences, as the optimal model for explaining variance in the intention. Implications for developing more effective educational campaigns are discussed
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