1,720,998 research outputs found
The effect of recycled plastic aggregate on chemico-physical and functional properties of composite mortars
No full textIn this paper the interaction mechanism between recycled plastic aggregates and lime matrix in composite mortars was investigated by means of thermal, morphological and FTIR analyses. In order to assess the fire behavior of the composite mortars, a cone calorimeter method was adopted. The plastic aggregate, mainly made of polyolefin and polyethylene terephthalate, is obtained from an industrial waste, through a process that provides a plasticization and densification by extrusion of plastic waste. Several composite mortars were prepared by replacing silica powder with 10, 15 and 20 % of recycled aggregate. Experimental results attest that, even if the filler was not chemically modified, there is a good chemical interaction between the plastic aggregate and mortar, involving a reduction of the negative effects on physical and functional properties of the mortar composites, such as thermal degradation and fire resistance. In fact all the specimens showed a scarce sensitivity to flashover, and can be classified as low risk materials
Mechanical and chemical properties of composite materials made of dredged sediments in a fly-ash based geopolymer
No full textDredging activity in harbours and channels produces huge quantities of sediments, generally considered as waste soil (WS) to be disposed: the management of such sediments is a great environmental problem for many countries worldwide. Among the recycling possibilities, the use of dredged sediments for the manufacture of geopolymer-based materials seems to be an interesting alternative to disposal, due to their low cost and easy availability. In order to analyse the possibility to use these geopolymer materials as building materials - for instance as precast construction elements in maritime projects - a multi-disciplinary research activity has been developed at the Federico II University of Napoli (Italy). Some experimental tests have been carried out on different geopolymeric specimens made by mixing sediments from Napoli 'harbour and industrial fly ashes produced by a power plant in the South of Italy. A siliceous sand was used for comparison as an inert reference material. Chemical, morphological and mechanical properties of different specimens have been studied by X-ray diffraction, Scanning Electron Microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and finally unconfined compression tests. The experimental results highlight that the use of dredged sediments in combination with fly ash can lead to geopolymeric matrices with interesting mechanical performances. Some differences in the microstructure of the geocomposite built with the siliceous sand or the dredged materials were found. In terms of environmental impacts, on the basis of standard leaching tests and according to Italian thresholds, the adopted dredged mixtures satisfy the prescribed limit for inert or non hazardous waste
Strategies for the valorization of soil waste by geopolymer production: An overview
No full textThe management of huge amounts of waste deriving from several anthropogenic activities, such as manufacturing, construction, mining and quarrying, dredging, represents a great contemporary environmental challenge for many countries worldwide. Among the different recycling possibilities, the use of the excavated soils, obtained from operations such as tunneling, excavations, mining, dredging etc., which are generally considered as soil waste, in the production of innovative eco-sustainable building materials represents an interesting alternative to their disposal. In fact, considering especially their chemical composition, low cost and easy availability, soil wastes seem to be the ideal candidates to be used as secondary raw materials for the manufacture of geopolymer-based materials. The paper intends to present a review of the recent scientific literature regarding the use of different types of soil waste to produce geopolymeric binders. Particular attention is focused on mining waste (deriving from various types of mining industries) and dredged sediments coming from marine harbors and natural and artificial water reservoirs, in order to understand and critically discuss the limits of their disposal approach and, at the same time, show perspectives and challenges for possible future research activities in this field. The production of geopolymer-based building components, starting from mining waste and reservoir sediments, is widely discussed thanks to the numerous scientific findings, while the recycling of marine dredged sediments through geopolymerization represents a completely new and innovative trend in research activity, in fact only few related papers were found in literature. It can be strongly stated that geopolymerization can significantly contribute to a sustainable improvement of soil waste management systems
Weathering Tests on Raw and Consolidated Vicenza Stone
Full text linkThe preservation of cultural heritage, particularly historical stone structures, represents a very challenging matter due to several environmental and anthropogenic factors. Vicenza stone, a calcareous rock known for its historical significance and widespread use in architectural masterpieces, requires significant attention for conservation. In fact, as the demand for sustainable and effective preservation methods intensifies, the exploration of innovative consolidation strategies becomes essential. To this end, inorganic consolidants, based on alkaline silicate formulations and nano-silica, were explored for their promising performance in enhancing the surface properties and chemical stability of Vicenza stone. In particular, the durability of treated and untreated Vicenza stone samples was evaluated by means of accelerated weathering tests such as freeze–thaw cycles, salt crystallization and simulation of acid rain. The experimental results revealed that Vicenza stone is very resistant to the effects of freeze–thaw cycles and acid rain; both the accelerated weathering tests did not show significant differences between treated and untreated VS samples. A different behavior was detected for the test for resistance to salt crystallization, whose findings led us to deduce that, for this kind of degradation, it is possible to observe a more beneficial effect of the consolidation treatments on the stone durability
New therapeutic targets for endometrial cancer: a glimpse into the preclinical sphere
No full textIntroductionEndometrial cancer (EC) is the only gynecologic malignancy showing increasing trends in incidence and mortality. While standard treatment has been effective primarily for early-stage EC, precision medicine with tailored therapy has revolutionized the management of this disease. Genome sequencing analyses have identified four sub-types of EC. Treatments for primary and metastatic disease can now be tailored more accurately to achieve better oncologic results.Areas coveredThis review provides an overview of the most relevant and updated evidence in the literature regarding EC molecular analysis and its role in risk classification, prognostication, and guidance for tailored and target therapies in early and advanced/metastatic stages. In addition, it provides updated information on optimal surgical management based on molecular classification and highlights key advances and future strategies.Expert opinionEC molecular analysis yields the potential of tailoring adjuvant treatment by escalating or deescalating therapy, as shown for POLE-mutated and p53-mutated tumors. Moreover, the expression of specific molecular signatures offers the possibility to employ novel target therapies, such as immune-checkpoint inhibitors that have demonstrated a significant benefit on prognosis. New treatment guidelines are still being established, and ongoing studies are exploring the potential prognostic role of further sub-stratifications of the four molecular classes and treatment options.Endometrial cancer (EC) is the only female cancer that is increasing among women. While the usual treatments work best when the disease is caught early, new advances in genetic studies have greatly improved the management of the disease. Four sub-types of EC have been identified. They are called: POLE-mutated, MMR-deficient, p53-abnormal, and no specific molecular profile. Treatments for EC can now be tailored more accurately to achieve better results. This review gives an overview of the most new and important evidence in the scientific literature about the molecular analysis of EC and how it can be used to help tailor the best treatments and surgeries for women with EC
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
Manufacturing and mechanical performance of lightened gypsum reinforced by hemp/epoxy composites
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