80,772 research outputs found
Spiking Chemical Sensor (SCS): A new platform for neuro-chemical sensing
No full textPublished versio
Towards a Reconfigurable Sense-and-Stimulate Neural Interface Generating Biphasic Interleaved Stimulus
No full textPublished versio
Non-destructive evaluation of cement-based materials from pressure-stimulated electrical emission - Preliminary results
No full textThis is the post-print version of the final paper published in Construction and Building Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.This paper introduces the possibility of in situ assessment of loading and remaining strength in concrete structures by means of measuring discharge of electric current from loaded specimens.
The paper demonstrates that the techniques have been applied to other rock-like materials, but that for the first time they are applied to cement-based materials and a theoretical model is proposed in relation to the appearance of electrical signals during sample loading and up to fracture.
A series of laboratory experiments on cement mortar specimens in simple uniaxial compression, and subsequently in bending – hence displaying both tension and compression – are described and show clear correlations between resulting strains and currents measured. Under uniaxial loading there is a well-defined relationship between the pressure-stimulated current (PSC) as a result of a monotonic mechanical loading regime. Similar results are observed in the three-point bending tests where a range of loading regimes is studied, including stepped changes in loading.
While currents can be measured at low strains, best results seem to be obtained when strains approach and exceed yield stress values.
This technique clearly has immense potential for structural health monitoring of cement-based structures. Both intermittent and continuous monitoring becomes possible, and given an ongoing campaign of monitoring, remaining strength can be estimated
Results of the Heart Protection Study: Can we still assume a class effect?
No full textStatins share several common features including the mechanism of action, i.e. inhibition of HMG-CoA reductase, as well as LDL-cholesterol (LDL-C) and triglyceride lowering properties. However, statins show minor differences in chemical structure, lipophilicity that could translate into a different pharmacological properties. For example, simvastatin exerted a more favorable effect on HDL-C levels than did atorvastatin when higher doses of the two drugs were compared. Finally, the major considerations to chose between statins for CVD patient therapy include clinical benefits and safety (i.e. evidence-based medicine). Primary prevention trials with pravastatins and lovastatin and secondary prevention trials with pravastatin, fluvastatin and simvastatin have established the clinical benefits of statins. In addition, HPS study was designed to investigate the benefits of simvastatin 40 mg in a broad range of patients at high risk for heart disease including women, the elderly and those with a history of hearth attacks, diabetes, hypertension or vascular disease. The results show the ability of simvastatin to reduce all causes of mortality, vascular death and cardiovascular morbidity. The trial also confirms the safety of simvastatin 40 mg although 60% of patients were receiving additional pharmacological treatment. In summary, it appears that statins are not the same and the choice of the more appropriate statin in high-risk patients should be driven by the evidence-based medicine both in terms of safety and efficacy
A Relational Unsupervised Approach to Author Identification
No full textIn the last decades speaking and writing habits have changed.
Many works faced the author identification task by exploiting frequencybased
approaches, numeric techniques or writing style analysis. Following
the last approach we propose a technique for author identification
based on First-Order Logic. Specifically, we translate the complex data
represented by natural language text to complex (relational) patterns
that represent the writing style of an author. Then, we model an author
as the result of clustering the relational descriptions associated to the
sentences. The underlying idea is that such a model can express the typical
way in which an author composes the sentences in his writings. So,
if we can map such writing habits from the unknown-author model to
the known-author model, we can conclude that the author is the same.
Preliminary results are promising and the approach seems viable in real
contexts since it does not need a training phase and performs well also
with short texts
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Numerical predictions of the fatigue life of aluminium welded joints
No full textThe fatigue life of arc welded joints made of aluminium alloy has been investigated by means of the implicit gradient method. This approach is suitable for estimating the fatigue life of welded joints characterised by different opening angles of the fillet weld and different thicknesses. The main fatigue data are related to cruciform joints, rectangular hollow section T-joints and bead removed joints. Using the principal stress as the local equivalent stress and a notch tip of the weld toe radius equal to zero, the paper analyses about two hundred experimental data taken from the literature and proposes a universal scatter band in the range of 104 to 5·106 cycles. This scatter band has an inverse slope around 4 and, at high cycle fatigue, the strength is about half that of steel joints. However, the scatter band is similar to welded joints made of steel previously analyse
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
Detection of weak stochastic forces in a parametrically stabilized micro-optomechanical system
No full textMeasuring a weak force is an important task for micromechanical systems, both when using devices as sensitive detectors and, particularly, in experiments of quantum mechanics. The optimal strategy for resolving a weak stochastic signal force on a huge background (typically given by thermal noise) is a crucial and debated topic, and the stability of the mechanical resonance is a further, related critical issue. We introduce and analyze the parametric control of the optical spring, which allows us to stabilize the resonance and provides a phase reference for the oscillator motion, yet conserving a free evolution in one quadrature of the phase space. We also study quantitatively the characteristics of our micro-optomechanical system as detector of stochastic force for short measurement times (for quick, high-resolution monitoring) as well as for the longer-term observations that optimize the sensitivity. We compare a simple strategy based on the evaluation of the variance of the displacement which is a widely used technique) with an optimal Wiener-Kolmogorov data analysis. We show that, due to the parametric stabilization of the effective susceptibility, we can more efficiently implement Wiener filtering, and we investigate how this strategy improves the performance of our system. We finally demonstrate the possibility to resolve stochastic force variations well below 1% of the thermal noise.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
- …
