Grafting maleic anhydride onto polypropylene in the presence of nanoclay-supported peroxide mechanism (Muñoz et al., 2021).
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•Macroradical recombination at high temperatures leads an ...almost negligible chain-scission rate after 3 minutes of reaction.•During grafting, MA homopolymerization takes place and is enhanced by the presence of o-MMT through chemical adsorption.•The via-radical reaction can be suppressed by using free radicals, enabling the collection of data on the reaction kinetics.•The kinetic data demonstrated the need to account for the effects of MA homopolymerization and PP macroradical recombination.
The kinetics of grafting and chain scission reactions during maleic anhydride (MA) grafting onto polypropylene (PP) using nanoclay-supported peroxide (o-MMT/DCP) in the molten state were evaluated through the development of a new methodology. A combination of characterization techniques and mathematical data manipulation was employed for this assessment. To inhibit radical propagation and recombination, tetramethylpiperidine-1-oxyl (TEMPO) was used as a free radical scavenger. Rheological stability tests demonstrated that TEMPO was more effective as a reaction inhibitor. The kinetics dataindicated that the use of o-MMT/DCP resulted in products with higher MA grafted levels and molecular weight (MW) compared to grafting performed in the absence of o-MMT. Additionally, some changes in molecular architecture were observed. The chain scission distribution function (CSDF) revealed that during the MA grafting process, the molecular weight of PP was reduced through chain scission, with a preference for longer chains. Furthermore, the presence of o-MMT was found to restrain the level of PP chain scission, likely due to recombination on the clay surface.
Background
The present study aimed to evaluate hard and soft tissue parameters around implants placed in augmented posterior mandible, comparing Ti‐reinforced d‐PTFE membranes with Ti‐meshes covered ...with collagen membranes, after 3 years of follow‐up.
Materials and Methods
Forty eligible patients were randomly assigned to group A (Ti‐reinforced d‐PTFE membrane) or group B (mesh covered with collagen membrane) for vertical ridge augmentation (VRA) and simultaneous implants. Implants were evaluated using specific peri‐implant parameters for bone and soft tissues: probing pocket depth (PPD), modified plaque index (mPI), bleeding on probing (BoP), modified gingival index (mGI), thickness of keratinized tissue (tKT), width of keratinized tissue (wKT), fornix depth (FD), peri‐implant bone level (PBL), interproximal bone peaks (IBP), marginal bone loss (MBL), interproximal bone loss (IBL).
Results
A total of 28 patients with 79 implants were evaluated after 3 years of follow‐up. The mean value of MBL was 0.70 mm (group A = 0.73 mm; group B = 0.71 mm), while mean IBL was 0.54 mm (group A = 0.64 mm; group B = 0.40 mm). The treatment with meshes resulted not inferior to PTFE and their clinical results appeared similar. A strong correlation between PBL and IBP was confirmed. Both study groups showed an increase of tKT and wKT values.
Conclusion
In the posterior mandible, VRA using both techniques provides stable PBLs up to 3 years. A correct soft tissue management and a strict professional oral hygiene protocol play a crucial role on peri‐implant health over time.
As dangerous climate change becomes more and more likely, a consensus has been reached on the importance of addressing Loss and Damage (L&D) residual to mitigation (i.e., preventing climate change) ...and adaptation (i.e., adjusting in order to avert adverse impacts). In spite of sharp divisions in terms of how to understand and operationalize L&D, most approaches draw on classic environmental governance, with discrete analogic interventions implemented by States and international actors. L&D is mainly envisioned as an “international court of climate justice” that identifies the culprits (emitters), quantifies harm, and compensates victims. While digital technologies and algorithmic governance have colonized many germane policy fields and virtually all economic sectors, in the L&D field a substantive discussion on the use of information and communication technologies, algorithms, and user‐generated data has been conspicuously absent. By taking the prospect of a “digitalization” of L&D seriously, this advanced review identifies the seeds of emerging digitalized approaches to L&D through an overview of literature. We focus on examples in three key domains associated with L&D—insurance, disaster responses and risk management, and human displacement. These empirical cases are used to investigate the modes of governance that accompany the digital tools through which L&D could be implemented, and the profound changes in climate politics and justice that would accompany a digitalization/algorithmization of L&D.
This article is categorized under:
Social Status of Climate Change Knowledge > Climate Science and Decision Making
How could digital technologies reshape “Loss and Damage” from climate change? Overview of empirical cases (“seeds”) and future outlooks.
Geothermal areas are typically characterised by the presence of gases and odours in the background atmosphere, stemming from natural emissions and possible mining exploitation of the area. This study ...presents the first olfactometric investigation of endogenous gas emissions from natural and archaeo-industrial vents in a geothermal area. Mt. Amiata is known for its complex geology and historical cinnabar mining. This study offers an inventory of spot gas emissions, not only in terms of odour and chemical concentration but also including flux data, a ground-breaking achievement in this field. The primary challenge of this investigation was estimating the emitted flow from ground holes or mine entrances, posing the risk of hazardous anoxic conditions. To address this challenge, an innovative and adaptive approach was adopted. The main breakthrough method involved the adaptation of a balometer, typically employed for indoor ventilation systems, to measure the flow of endogenous gases. Field surveys revealed odour concentrations that can exceed 106 of ouE/m3, surpassing industrial emission level considerably. Chemical concentrations, primarily consisted of CO2 (80/90 %v/v) and CH4 (∼10%v/v), providing critical insights into the global warming potential (GWP) associated with natural emissions. Moreover, these spots, often located at ground level and lacking a substantial atmospheric dilution, pose potential risks to nearby individuals, with concentrations of gases such as H2S surpassing safety thresholds. Total emissive flux of the investigated spot vents in the Mt. Amiata area, showed that the emission rate of H2S is notably substantial (55 kg/h), roughly equivalent to emissions from approximately four 20 MW geothermal plants, as along with odour emission rates in the order of 107 ouE/s. Considering the GWP derived from emitted gases, the total inventory assessment of the spot vents resulted in 36 t/h or 23 t/h CO2eq, depending on the time horizon considered (GWP20 or GWP100 respectively).
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•Mt. Amiata district is an important geothermal area, rich in gas spot vents.•The main components of vent emissions were CO2, CH4 and H2S.•Odour concentrations measured at these emissions were very high (106 ouE/m3).•Different hood strategies have been used for the measurement of gaseous flowrate.•Total measured spot vent fluxes were 55 kg/h of H2S, 16 t/h of CO2, 280 kg/h of CH4.
The interest of the aerospace industries in structural health and usage monitoring systems is continuously increasing. Among the techniques available in literature those based on Fibre Bragg Grating ...sensors are much promising thanks to their peculiarities. Different Chirped Bragg Grating sensor configurations have been investigated in this paper. Starting from a numerical model capable of simulating the spectral response of a grating subjected to a generic strain profile (direct problem), a new code has been developed, allowing strain reconstruction from the experimental validation of the program, carried out through different loading cases applied on a chirped grating. The wavelength of the reflection spectrum for a chirped FBG has a one-to-one correspondence to the position along the gauge section, thus allowing strain reconstruction over the entire sensor length. Tests conducted on chirped FBGs also evidenced their potential for SHM applications, if coupled with appropriate numerical strain reconstructions tools. Finally, a new class of sensors-Draw Tower Grating arrays-has been studied. These sensors are applicable to distributed sensing and load reconstruction over large structures, thanks to their greater length. Three configurations have been evaluated, having different spatial and spectral characteristics, in order to explore possible applications of such sensors to SHM systems.
DeXAR Arrotta, Luca; Civitarese, Gabriele; Bettini, Claudio
Proceedings of ACM on interactive, mobile, wearable and ubiquitous technologies,
03/2022, Letnik:
6, Številka:
1
Journal Article
Recenzirano
The sensor-based recognition of Activities of Daily Living (ADLs) in smart-home environments is an active research area, with relevant applications in healthcare and ambient assisted living. The ...application of Explainable Artificial Intelligence (XAI) to ADLs recognition has the potential of making this process trusted, transparent and understandable. The few works that investigated this problem considered only interpretable machine learning models. In this work, we propose DeXAR, a novel methodology to transform sensor data into semantic images to take advantage of XAI methods based on Convolutional Neural Networks (CNN). We apply different XAI approaches for deep learning and, from the resulting heat maps, we generate explanations in natural language. In order to identify the most effective XAI method, we performed extensive experiments on two different datasets, with both a common-knowledge and a user-based evaluation. The results of a user study show that the white-box XAI method based on prototypes is the most effective.
Climate-induced migration, and particularly the issue of climate refugees, is subject to growing attention in global climate governance. The debate on the topic sees the convergence of conflicting ...discourses (ranging from those of conservative European governments to southern NGOs) onto apocalyptic narratives that forecast massive, abrupt and unavoidable flows of climate refugees. Such dystopian narratives, either framed within humanitarian or anational securitya agendas, relegate the concerned populations to the status of victims (either to protect or to fear). This article, applying elements of poststructuralist discourse theory, analyzes the narratives via a set of influential reports on climate-induced migration and argues that apocalyptic narratives on climate refugees, although not totalizing or uncontested, represent a case of the depoliticization of global climate governance. The convergence into such narratives favors the drive towards a post-political discursive configuration, which, by supplanting politics with governance, leaves underlying power relations untouched and (re)produces present forms of representational and material marginalization. It therefore argues that such narratives, although often employed with the aim of attracting attention to a pressing issue, are detrimental for an emancipatory approach to climate change.
Abstract
In this paper we present a method to compute spatial and time evolution of electromagnetic forces in magnetic confinement fusion devices based on a combination of signal analysis of magnetic ...measurements with a simple electromagnetic modelling. The method allows analyzing the whole plasma discharge including fast transient phenomena such as fast terminations or disruptions. It has been tested and verified on RFX-mod, an experiment equipped with a non-continuous toroidal passive stabilizing shell, but it can be applied to cases with continuous wall such as tokamak devices, as well. An experimental plasma discharge, with a fast termination phenomenon at the end of the flat-top phase, has been analyzed and the related forces have been computed by using two different sets of data: synthetic magnetic field measurements provided by ANSYS simulation and real experimental ones. The results are in good agreement in all the phases of the plasma discharge. Moreover, because of the very low-computational requirements, it is shown that the presented method can be used as a tool for real-time monitoring of the electromagnetic forces on the shell to be integrated in the protection system of the future RFX-mod2 experiment.
Emotions play an important role in the work of teachers serving students with emotional and behavioral disabilities (EBD), yet little is known about teachers’ momentary affective experiences. In this ...study, we collected 710 surveys regarding momentary affect from 14 teachers of students with EBD. We used descriptive analysis and variance decomposition to examine the frequency, intensity, and variability of these experiences. We then tested a series of models to explore how specific professional activities relate to teachers’ momentary affect. We found that teachers experienced positive affect more frequently and intensely than negative affect and that large proportions of the variation in positive and negative affect can be attributed to variation within individual teachers across time points. For these teachers, engaging in discipline was significantly associated with a higher negative affect, whereas engaging in instructional activities was associated with a higher positive affect. We discuss implications for researchers and practitioners.
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