1,722,019 research outputs found
Non-invasive sensing for food reassurance
No full textConsumers and governments are increasingly interested in the safety, authenticity and quality of food commodities. This has driven attention towards non-invasive sensing techniques used for rapid analyzing these commodities. This paper provides an overview of the state of the art in, and available alternatives for, food assurance based on non-invasive sensing techniques. The main food quality traits of interest using non-invasive sensing techniques are sensory characteristics, chemical composition, physicochemical properties, health-protecting properties, nutritional characteristics and safety. A wide range of non-invasive sensing techniques, from optical, acoustical, electrical, to nuclear magnetic, x-ray, biosensor, microwave and terahertz, are organized according to physical principle. Some of these techniques are now in a period of transition between experimental and applied utilization and several sensors and instruments are reviewed. With continued innovation and attention to key challenges, such non-invasive sensors and biosensors are expected to open up new exciting avenues in the field of portable and wearable wireless sensing devices and connecting with mobile networks, thus finding considerable use in a wide range of food assurance applications. The need for an appropriate regulatory framework is emphasized which acts to exclude unwanted components in foods and includes needed components, with sensors as part of a reassurance framework supporting regulation and food chain management. The integration of these sensor modalities into a single technological and commercial platform offers an opportunity for a paradigm shift in food reassurance
Analytical study of the bond behavior of fiber reinforced cementitious matrix (FRCM)-substrate joints based on a two-stage nonlinear cohesive material law
No full textExternally bonding fiber-reinforced cementitious matrix (FRCM) composite to the surface of concrete or masonry members is an effective technique to improve the performance of existing structures. In many cases, interfacial debonding between the FRCM fiber textile and embedding matrix governs the capacity of FRCM-strengthened structures. The interfacial debonding process can be studied analytically by assuming a cohesive material law (CML), which represents the relationship between interfacial shear stress and slip. In this study, a two-stage function with an exponential stage and a constant stage is proposed to describe the CML associated with the matrix-fiber interface. The latter stage is characterized by a constant shear stress to account for the friction/interlocking between the matrix and fiber observed in experimental tests. With the assumed CML, the full-range loading response was obtained. Additionally, the interfacial slip, fiber axial strain, and interfacial shear stress were analytically derived. The parameters of the two-stage CMLs for PBO, glass, and carbon FRCM were inversely determined by matching the analytical relationships of peak applied axial stresses associated with different bonded lengths with the experimental ones. Considering the inversely determined CMLs, the predicted load responses and strain profiles showed good agreement with the measurements of direct shear test specimens
Investigation of the bond behavior of the fiber reinforced composite-concrete interface using the finite difference method (FDM)
No full textFiber reinforced composite materials, including fiber reinforced polymer (FRP) and fiber reinforced cementitious matrix (FRCM), have been widely used to increase the load-carrying capacity and ductility of concrete structures. The bond-slip relationship of the composite-concrete interface is of pivotal significance to understand the behavior of the strengthened structure. This study presents a generic and versatile finite difference method (FDM) solution that can predict the full-range bond behavior of the composite-concrete interface adopting different (e.g., bilinear, trilinear, exponential, and their combinations) bond-slip relationships. The proposed FDM solution successfully captures the snap-back phenomenon using an arc-length method for iteration. Comparison between FDM and analytical results shows that (i) for some frequently adopted analytical solutions, the assumption of zero slip at the composite free end is not suitable for short bonded lengths and fails to capture the snap-back phenomenon and load descending stage for long bonded lengths; (ii) for bond-slip relationships with different shapes, the load responses are similar but the effective bond lengths can be different when the same fracture energy is enforced; and (iii) for composite-concrete joints with finite bonded length, the peak load may not be the same when adopting different bond-slip relationships with the same fracture energy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Application of a trilinear bond-slip model to FRCM-concrete joints
No full textThis study presents an analytical approach for predicting the load-slip response of fiber reinforced cementitious matrix (FRCM)-concrete joints. The FRCM-concrete interfacial behavior was described with a trilinear cohesive material law consisting of a linear stage, a softening stage, and a friction stage. Accordingly, provided that the bonded length is longer than the composite effective bond length, the full-range applied load-global slip response consists of five stages: an elastic stage, an elastic-softening stage, an elastic-softening-debonding stage, a softening-debonding stage, and finally a fully debonded stage. Closed-form solutions for the applied load-global slip, interfacial shear stress distribution, and longitudinal stress distribution along the composite bonded length were derived. Also, the debonding load, peak load, and the effective bond length were analytically obtained. Results of the analytical model were compared to experimental results of six single-lap shear specimens instrumented with strain gauges mounted to the longitudinal fibers along the composite bonded length
Will More Expressive Graph Neural Networks do Better on Generative Tasks?
No full textGraph generation poses a significant challenge as it involves predicting a complete graph with multiple nodes and edges based on simply a given label. This task also carries fundamental importance to numerous real-world applications, including de-novo drug and molecular design. In recent years, several successful methods have emerged in the field of graph generation. However, these approaches suffer from two significant shortcomings: (1) the underlying Graph Neural Network (GNN) architectures used in these methods are often underexplored; and (2) these methods are often evaluated on only a limited number of metrics. To fill this gap, we investigate the expressiveness of GNNs under the context of the molecular graph generation task, by replacing the underlying GNNs of graph generative models with more expressive GNNs. Specifically, we analyse the performance of six GNNs in two different generative frameworks—autoregressive generation models, such as GCPN and GraphAF, and one-shot generation models, such as GraphEBM—on six different molecular generative objectives on the ZINC-250k dataset. Through our extensive experiments, we demonstrate that advanced GNNs can indeed improve the performance of GCPN, GraphAF, and GraphEBM on molecular generation tasks, but GNN expressiveness is not a necessary condition for a good GNN-based generative model. Moreover, we show that GCPN and GraphAF with advanced GNNs can achieve state-of-the-art results across 17 other non-GNN-based graph generative approaches, such as variational autoencoders and Bayesian optimisation models, on the proposed molecular generative objectives (DRD2, Median1, Median2), which are important metrics for de-novo molecular design
Observing the effect of the athmospheric electric field inside thunderstroms on the EAS with the ARGO-YBJ experiment
No full textThe strong atmospheric electric fields inside thunderstorms can have a significant effect on the electromagnetic component of cosmic ray air showers. Detecting this effect is particularly important in understanding the relation between the showers and lightning. Some episodes in which intensely changed atmospheric electric field during thunderstorms affect the counting rate of single particle have been recorded by ARGO-YBJ experiment. One of the episodes is discussed carefully, which happened in the morning of July 20, 2009 (Beijing Time). A short duration (∼20 minutes) significant increase of the single particle counting rate with low energy occurs accompanied with strong atmospheric electric field, while a decrease happens in the counting of particles with higher energ
Nostalgia increases financial risk-taking
No full textWe examined, in five studies, the relation between nostalgia and financial risk taking. We hypothesized that nostalgia increases risk taking by fostering perceptions of social support. In Study 1, we established the basic effect of nostalgia and increased risk taking. In Study 2, we used a measurement-of-mediation approach to specify the underlying mechanism. Perceived support from family members, rather than from significant others or friends, mediated the relation between nostalgia and risk taking. In Studies 3-4, we further specified the mediating mechanism (i.e., family social support) and established direction of causality by using an experimental-causal-chain approach. Finally, in Study 5, we provided direct experimental evidence of the full mediation model. Taken together, nostalgia galvanizes perceived family support, which propels individuals toward financial risk
Nostalgia for host culture facilitates repatriation success: the role of self-continuity
No full textRepatriation (returning home after having lived abroad) can be psychologically distressing. We theorized and found evidence that feeling nostalgic about a host culture contributes to repatriation success. We tested a sample of over 700 international teachers who worked in the United States (host culture) and then returned to their home countries. As hypothesized, nostalgia for the host culture was positively associated with repatriates’ self-continuity (a sense of connection between one’s past and present selves). Self-continuity, in turn, mediated the positive relation between host-culture nostalgia and psychological adjustment (self-esteem, approach motivation, job satisfaction). The findings have implications for the literatures on (a) multicultural experience and repatriation, and (b) the emotion of nostalgia and its relation to psychological adjustment
- …
