213 research outputs found
Pieter de Loose and Michiel Verbiest gilded table with marquetry table top: conservation treatment and research.
No full textThe article will examine the conservation treatment on one of the Peeter de Loose and Michel Verbiest masterpieces: the gilded table with marquetry table top from 1689, that is part of the Rijksmuseum collection. The intervention was performed due to an accident that has caused structural and superficial damages on the gilded base. The treatment mainly focused on one of the cherub figures. Preliminary non-invasive analyses where conduct in order to properly evaluate the state of conservation. Important informations were discovered thanks to the x-ray imaging, such as the construction of the figure and the presence of previous restorations. Due to the condition of the gilding and the wooden support, a preliminary consolidation and adhesion of the fragments was required. The structural damages, mainly located on the left leg, were fixed with animal glue. The losses and cracks were filled with gesso and retouched with gouache colors. The conservation treatment was part of the internship that Corinne Suraci has done at the Furniture conservation studio of the Rijksmuseum. The proposal was discussed with the Head of the Studio Paul van Duin and with the Junior Furniture Conservator Jan Dorshied. The treatment was a perfect occasion to deepen the study on the gilding, starting with the comparison between the collected data from the analyses and the cleaning test. The gilding is covered by various overpainting which give to the base a patchy appearance. Chemical cleaning test was performed with mixture of solvent and aqueous solution. The test has led to bibliographic research on the methods currently in use to remove bronze paints on top of a water sensitive surface such as a water gilding. As a result of the studies a proper methodology is proposed in this article. The complete treatment is expected to take six months
Analysis on the impact of additives on space charge behavior of thermally aged XLPE plaques
No full textThis article investigates the space charge properties of XLPE-based materials characterized by different concentration and types of additives and fillers inside the polymeric compound. Materials were aged under three different temperatures (87 °C, 110 °C and 130 °C) for 24, 18 and 12 months, respectively. Space charge profiles of both unaged and aged materials were obtained through the Pulsed Electro Acoustic (PEA) method. Additives and fillers are proven to significantly impact the space charge behavior of the insulating material both in the unaged and aged states. The impact of antioxidants, together with their kinetics under thermal aging conditions, is analyzed and claims an effective containment of the degradation kinetics, keeping the accumulated space charge to low values
About electrical and mechanical behaviour of low-voltage I&C cables used in nuclear power plants
No full textThis paper focuses on the electrical and mechanical properties of irradiated and thermally-stressed NPP cables used for instrumentation and control (I&C). These cables show some noteworthy changes after few years of uncontrolled environment conditions due to a phenomenon called post-irradiation effect. Strong post-irradiation effects, e.g. reduction of mechanical properties, raise of crosslinking and oxidation grade, were found on XLPE cable insulation years after irradiation. These degradation mechanisms can be correlated with electrical measurements in which imaginary permittivity values raise, in particular at low-frequencies where interfacial phenomena take place. This behavior can be linked to the increase of interfacial area between amorphous and crystalline region of polymer, supporting the evidence that post-irradiation effects can lead to polymer crosslinking during a storage period even at room temperature
After the earthquake. Design processes for intervention on vernacular heritage in Central Italy
No full text[EN] Every day, in Italy, an average of 45 seismic events is recorded (INGV 2020 data) and their impact on the built environment is intense and continuous. The most notable cases are only the tip of a widespread and systematic iceberg, especially in the Central Apennines Mountain range. The opportunity to operate on ancient and disrupted buildings, to observe materially mural stratigraphies, to interpret disconnected or hinted geometries represents the field of action of know-how that fluctuates between technological specialism and the transmission of ancient tacit knowledge, which is more evident in the vernacular heritage. Concepts like conservation, restoration and reconstruction have become crucial in the deep debate and rule formulation, in the context of the “Extraordinary Commissariat for Earthquake Reconstruction 2016”. The contribution intends to investigate and describe the main features of these design procedures, focusing on the results, the perspective, dynamics, and objectives through which the reconstruction is taking place. More in detail, the paper suggests two case studies to examine the application of these ongoing procedures in relation to the enhancement and conservation of vernacular heritage in the Marche region. The two case studies are the village of Gabbiano (a small rural fabric close to Pieve Torina, Macerata) and the Shrine of Macereto (a monumental, isolated complex in Visso, Macerata). The differences in size, type and original use between the case studies offers the opportunity to compare two different interventions for either a complete reconstruction or a conservative restoration. The scope of the study is to explore the “rules of reconstruction” - applied to vernacular heritage sites - by observing how the projects and the proposed techniques represent an interpretation of the national legal framework built around the post-earthquake territories. Loffredo, G.; Recla, F.; Suraci, N.; Tosco, C. (2022). After the earthquake. Design processes for intervention on vernacular heritage in Central Italy. En Proceedings HERITAGE 2022 - International Conference on Vernacular Heritage: Culture, People and Sustainability. Editorial Universitat Politècnica de València. 871-878. https://doi.org/10.4995/HERITAGE2022.2022.15152OCS87187
Il contenuto di vitamina C nei pomodori in relazione alle modalità ed al grado di maturazione
No full text
Dielectric Spectroscopy as a Condition Monitoring Technique for Low-Voltage Cables: Onsite Aging Assessment and Sensitivity Analyses
No full textThis work presents the development, validation, and sensitivity analyses of a portable device capable of performing high-frequency dielectric spectroscopy tests on site. After a brief introduction on the operation principle and the description of the impact of frequency on dielectric spectroscopy, the article presents the results of tests on reference samples confirming good agreement with expected values. The frequency region in which the device operates, 1–200 kHz, was chosen because of its correlation with oxidative species of polymeric compound. The sensitivity analyses were performed measuring the dielectric response of low voltage cables with different aged lengths. The outcome of these tests is twofold. On the one hand, they confirm the suitability of the technique for aging evaluation, and, on the other hand, they allow the assessment of the minimum aged length (damage ratio) which causes appreciable variations on the obtained dielectric spectrum. This quantity was found to be ~35% of the total cable length
Broadband dielectric spectroscopy: A viable technique for aging assessment of low-voltage cable insulation used in nuclear power plants
No full textThis paper deals with the study of a non-destructive technique to detect the aging state of cable insulation used in a nuclear environment subjected to radiation and temperature aging. Cable samples were aged under dose rates ranging from 0.42 and 1.06 kGy/h at 55 and 85 °C. The imaginary part of the permittivity at 100 kHz is found to correlate well with mechanical properties, such as elongation at break, which is typically used to diagnose cable insulation, but it is a destructive property and cannot be used on field. It has been demonstrated also that a postirradiation effect occurs even years after aging is stopped, increasing the imaginary permittivity and worsening mechanical properties due to the slow conversion of radicals into oxidized species. The main consequence is that when cable insulation is subjected to a nuclear accident, releasing a huge amount of radiation, the health of cable insulation must be followed also for a long time after the accident occurred, since aging due to oxidation progresses even when the radiation source is switched off
Personalizable Service Discovery in Pervasive Systems
No full textToday, telecom providers are facing changing challenges.
To stay ahead in the competition and provide market
leading offerings, carriers need to enable a global ecosystem of
third party independent application developers to deliver converged
services. This is the aim of leveraging a open standardsbased
service delivery platform. To identify and to cope with
those challenges is the main target of the EU funded project
IST DAIDALOS II. And a central point to satisfy the changing
user needs is the provision of a well working, user friendly and
personalized service discovery. This paper describes our work
in the project on a middleware in a framework for pervasive
service usage. We have designed an architecture for it, that
enables full transparency to the user, grants high compatibility
and extendability by a modular and pluggable conception and
allows for interoperability with most known service discovery
protocols. Our Multi-Protocol Service Discovery and the Four
Phases Service Filtering concept enabling personalization should
allow for the best possible results in service discovery
Effects of Graphene Coatings on hindering Space Charge injection in Epoxy Resin
No full textThe reliability of epoxy resins (and dielectrics in general) employed for HVDC applications is significantly affected by space charge accumulation in the insulating material. Several methods have been tested to limit the injection and accumulation of space charge. In this work, planar specimens featuring graphene coatings were tested. Measurements of space charge accumulation, conductivity and permittivity at different temperatures (from 30°C to 60°C) and fields (from 30 kV/mm to 50 kV/mm) were carried out on epoxy specimens with and without coatings. Results show accumulation of space charge for low fields and temperatures in the reference specimens, while a reduction can be noticed with a layer of graphene coating. On the other hand, at higher fields or temperatures, the effect is reversed
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