1,720,979 research outputs found
Reuse and recycling in construction: novel photocatalytic nano-mortars from valorised industrial wastes
Full text linkProduction of novel eco-composite nano-mortars for architectural finishing, designed to combat environmental pollution affecting building shells, is reported. Specimens consist of a natural hydraulic lime mortar matrix doped with various kinds of nanophotocatalysts, produced from valorized industrial wastes: TiO2-hexaferrite from Fe3O2, and Ti(SO4)2-hydroxyapatite from Atlantic codfish bones. Samples were characterized and their photocatalytic activity was evaluated. Analysis showed that industrial wastes may be usefully reused to produce a new generation of sustainable, cheap and multifunctional novel building materials
Riuso e riciclo nell’industria delle costruzioni: nano-malte fotocatalitiche innovative da scarti industriali valorizzati
No full textQuesto lavoro discute della produzione di nanomalte innovative eco-composite per intonaco, progettate per combattere l’inquinamento impattante sull’involucro edilizio. I campioni sono costituiti da calce idraulica naturale funzionalizzata da vari tipi di fotocatalizzatori, prodotti a partire da scarti di industrie siderurgiche ed alimentari. Sono state condotte indagini chimico-fisiche ed, in particolare, è stata valutata l’attività fotocatalitica. Le analisi hanno dimostrato che i predetti scarti possono essere utilmente riciclati per produrre una nuova generazione di materiali da costruzione innovativi, sostenibili, economici e multifunzionali
The coffee-house: Upcycling spent coffee grounds for the production of green geopolymeric architectural energy-saving products
No full textThis study investigates a possible alternative reuse of spent coffee grounds (SCG), the major residue of the brewing process, to manufacture green geopolymeric materials for innovative building applications in energy-saving construction, in line with the European Green Deal towards zero-energy building. Specimens were prepared by a combination of biomass fly ash from the Kraft paper-pulp process, as
raw material (70 wt%), and SCG (up to 17.5 %), as filler. The high amount of reused bio-wastes makes the material fit the requirements for the Minimum Environmental Criteria (MEC) certification, in light of the Circular Economy (CE) approach. Sustainability is also boosted by the manufacturing process that completely occurred at ambient conditions (20 C, 65 % RH). Materials engineering performance is evaluated to predict possible applications in construction and promote an integrated architectural design process to propose a ‘‘coffee-house” equipped with an innovative energy structure and envelope. For the scope, different technological solutions are designed and virtual energy modelling is implemented to simulate the performance of a building model in different climatic conditions and estimate the possible real efficacy of the proposed solutions in relation to building efficiency and cost management, as envisaged by the EU 2018/844 on the buildings’ energy performance. The major result is that the developed material represents an optimum candidate to substitute traditional construction and building materials with a great manufacturing financial saving, up to 37 % for the 17.5 % SCG, and an energy improvement up to about 19 % per year, leading further saving in the yearly building management
Development of energy-saving innovative hydraulic mortars reusing spent coffee ground for applications in construction
No full textThis paper reports the development of green bio-composite mortars, obtained reusing spent coffee ground (SCG), an agri-food residue, in the light of the Circular Economy approach. This process can boost the sustainability in Construction and proposes an alternative to SCG disposal in landfill, potentially dangerous to humans and the environment. For the first time, specimens were produced and compared using different blends of conventional hydraulic binders (ordinary Portland cement and natural hydraulic lime); SCG partially substituted sand (up to 15 wt.%, with a 2.5% increment) for the aggregate mix. The manufacturing process was performed at ambient conditions (20°C, 65% RH) resulting highly sustainable, and consisted of simple operative steps reproducible in a real building site. The prepared mixes were fully characterised to assess their technological potentials in construction. Morphology analysis, performed by Scanning Electron Microscopy (SEM), showed SCG addition led to a more compact structure. Considering the functional properties, results widely range on binder blend base, offering various concrete applications; it was observed that with SCG addition, despite a decrease in the bulk density (up to 26%), the mechanical performance still remained suitable for proper masonry applications, according to the relevant standards (class of resistance M2.5-M10). A light water imbibition increase was registered (about 5%) while a significant decrease of the capillarity index was seen. Moreover, a robust thermal conductivity reduction was observed (up to 72%), making the mortars highly suitable for energy-saving uses in building. Finally, a reduction in the manufacturing cost (up to 8%) was calculated, granting significant financial saving in light of the industrial symbiosis. These encouraging results showed that reusing SCG not only provides numerous benefits to the overall building performance and management but it is also a valid alternative to usual SCG disposal. The high amount of reused bio-waste significantly widens the knowledge of greener and more efficient building sector, making the prepared mortars promising candidates for the Minimum Environmental Criteria certification, in light of the recent EU regulations, and in line with the principles of the Circular Economy
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
Photocatalytic nano-composite architectural lime mortar for degradation of urban pollutants under solar and visible (interior) light
No full textRecent advances in nano-technology and nano-additives can give enhanced properties to natural hydraulic lime (NHL), creating a multifunctional material. We have prepared a novel nanocomposite, made of a commercial mortar with 1 wt% and 5 wt% added titania nanoparticles (NPs). These TiO2 NPs are themselves doped with 1 mol% silver, to give the material enhanced photocatalytic and antimicrobial properties. The Ag-doped TiO2 NPs were made from a simple, costs effective, aqueous green nanosynthesis process, and the end material only contains 0.01–0.05% Ag. As this mortar is intended to both combat atmospheric pollution, and create more durable/lower maintenance building façades (plastering and finishing) by limiting attack from microorganisms and pollutants, its photocatalytic anti-pollution activity under solar and visible (no UV) light for nitrous oxide (NOx) and volatile organic compound (VOC) removal was studied. The addition of dopants did not significantly alter the physical properties or curing of the mortar, while it showed excellent photocatalytic activity under sunlight, The mortars with only 1 and 5 wt% additives degraded 10.6% and 21% NOx after 45 mins, respectively, comparing well to a value of 50% for a pure TiO2/Ag+ sample. They also degraded VOCs under visible light, of the kind used for lighting inside buildings, with no UV component. As the NPs are contained in the whole of the mortar layer, not just as a coating, if the surface is chipped or damaged this mortar will not loose its photocatalytic capabilities
Mineralogical and Optical Characterization of SiO2-, N-, and SiO2/N-Co-Doped Titania Nanopowders
No full textSilica, nitrogen, and nitrogen-plus-silica co-doped titania powders were synthesized via sol–gel method. The products of the synthesis were thermally treated in air and under ammonia flow. The determination of Si and/or N into the TiO2 lattice, and the doped samples' crystal structure, was made by means of X-ray powder diffraction, whilst the occurrence of amorphous phase was obtained using the combined Rietveld-RIR method. The optical properties of the powders were obtained by diffuse reflectance spectroscopy and their energy band gaps were calculated using the differential reflectance method. The photocatalytic activity of the doped samples was assessed in gas phase under UV-light and visible-light irradiation, monitoring the degradation of an organic compound. In addition, the morphology of the samples was further on characterized by means of HRTEM. Nitrogen, silica, and co-doping shifted the anatase-to-rutile (A [RIGHTWARDS ARROW] R) phase transition toward higher temperatures. Silica was found to enter the anatase lattice, and nitrogen was presumed to enter the titania crystal structure as well. Nitrogen doping and SiO2/N-co-doping shifted the light absorption toward the visible region
Variations on the Author
Full text link“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
Architectural technologies for life environment: Spent coffee ground reuse in lime-based mortars. A preliminary assessment for innovative green thermo-plasters
No full textSpent coffee ground, the residue obtained from the brewing process, is the primary unavoidable (inedible) waste from the coffee consumption. As coffee production and beverage consumption are increasing worldwide, a more sustainable waste management is required since the usual disposal in landfill is a liability to both humans and the environment. This paper is aimed at showing a possible alternative reuse of coffee ground wastes in novel green building materials intended for thermo-plastering applications in construction, in a circular economy context. Coffee waste was used in various percentages (up to 17.5%) to assess the engineering performance of the pro- duced bio-composite mortars. The main results showed that just a little amount of coffee waste determines a bulk density decrease up to 15.4% (making the products comparable to a structural lightweight conglomerate or a light plastering mortar), an extensive drop in mechanical performance (still maintaining acceptable values for the considered plastering application) and in thermal conductivity (up to 47%). Moreover, a multi-criteria analysis, not only able to consider the materials performance, but also aspects related to the environmental impact and the economic drawback, has been implemented resulting that the preferable mix would contain 10% waste. Finally, preparatory virtual energy simulations were implemented to analyse the performance of that mix in a simplified architectural model, revealing a sufficient energy improvement and a more efficacy in cold cli- mates. All considering, coffee waste can be effectively reused to manufacture green bio-composite thermo- plasters with adequate energy performance considering the main requirements of a building application
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