Experimental study aimed at highlighting warnings for proper design, construction and control of geocomposite-reinforced asphalt pavements

The proper use of interlayers in asphalt pavements can be an effective and economic option to enhance their service life. However, the presence of a foreign element at the interface should be properly taken into account during design, construction and control of reinforced pavements. Given this background, the present laboratory study investigated stiffness and interface bonding properties of reinforced asphalt systems in order to achieve fundamental information for a correct design as well as proper construction and control of reinforced pavements. To accomplish this objective, different composite reinforcements (grids/fabrics embedded in bituminous membranes) were studied as interlayers of double-layered systems prepared with both traditional and polymer-modified asphalt concretes. Dynamic flexural tests and static interface shear tests were carried out. Unreinforced reference systems was also studied for comparison purposes. Results confirmed the abovementioned warnings that will allow delineating some preliminary guidelines related to the use of reinforcements in pavements

Aesthetic and Mechanical Suitability of a Clear Synthetic Resin as a Unconventional Binder for Road Pavements

Current environmental awareness interests several aspects of civil engineering, including road construction. Indeed, new challenges related to environmental pollution and landscape preservation must be faced. In this sense, clear road pavement surfaces represent an effective technology aimed at guaranteeing environmental-friendly aesthetic pavements. The use of clear synthetic resin as a binder involves several benefits for the mitigation of in-service reached temperatures and the heat distribution within pavements (with appreciable effects on pavement mechanical performance too). The present paper illustrates an experimental study aimed at analysing the chromatic and mechanical properties of a clear synthetic resin and thus its suitability as a binder for road pavement mixes. Chromatic characteristics were assessed through digital image analysis at different aging conditions. A dynamic shear rheometer was used to evaluate the linear viscoelastic properties as well as fatigue and rutting potential of the binder in a wide range of temperatures and frequencies. A conventional 35/50 penetration grade bitumen was also investigated for comparison purposes. The clear resin exhibited limited changes in colour (darkening effects), mainly in the case of short-term aging. On the other hand, a low temperature-dependency of such a binder was observed up to 58\ub0C. Slightly increased aptitude to rutting at the higher temperatures was detected, even if it is worth noting that clear in-service mixtures would achieve lower temperatures than traditional "black" materials at a given environmental condition (air temperature, solar radiation, etc.). The resin also exhibited a softer behaviour, along with an enhanced fatigue resistance. Overall, the studied innovative binder showed promising results in view of its effective use in road paving

Steel slag as valuable aggregate in eco\u2013friendly mixtures for asphalt pavements

Research and application concerning the use of environmentally friendly materials and technologies in road pavements have reached high relevance mainly due to the increasing public consciousness addressed to environmental protection and preservation. In this sense, the possible use of steel slags for construction applications (including road pavements) has a strategic importance to convert a waste into a valuable resource, taking also into account that ferrous slag may have a lower potential to negatively impact the environment. The environmental sustainability of asphalt mixtures prepared with steel slags can be further enhanced adopting the so-called Warm Mix Asphalt (WMA) technology. In fact, WMA is an asphalt concrete modified with additives that can be produced and applied at lower temperatures than the traditional Hot Mix Asphalt (HMA), thus reducing energy consumption, gas and fume emissions. Given this background, the paper illustrates a part of a wide research study aimed at verifying the utilization feasibility of steel slags in warm asphalt concretes. In particular, midrange and high-service temperature properties as well as water susceptibility of warm mixtures containing steel slags were assessed in the laboratory. The warm modification was performed using a chemical tensoactive additive, whereas slags were taken from a metallurgical plant equipped with an electric arc furnace (EAF). A WMA prepared with only natural aggregates was also studied for comparison purpose. The performance characterization was carried out through both static and cyclic laboratory tests. The results mainly showed that asphalt mixtures prepared combining chemical warm technology and EAF steel slag aggregates demonstrate promising field applicability

Two-steps versus one-step solidification pathways of binary metallic nanodroplet

The solidification of AgCo, AgNi, and AgCu nanodroplets is studied by molecular dynamics simulations in the size range of 2-8 nm. All these systems tend to phase separate in the bulk solid with surface segregation of Ag. Despite these similarities, the simulations reveal clear differences in the solidification pathways. AgCo and AgNi already separate in the liquid phase, and they solidify in configurations close to equilibrium. They can show a two-step solidification process in which Co-/Ni-rich parts solidify at higher temperatures than the Ag-rich part. AgCu does not separate in the liquid and solidifies in one step, thereby remaining in a kinetically trapped state down to room temperature. The solidification mechanisms and the size dependence of the solidification temperatures are analyzed, finding qualitatively different behaviors in AgCo/AgNi compared to AgCu. These differences are rationalized by an analytical model

Trichobezoars in children: therapeutic complications

Trichobezoars are concretions formed by the accumulation of hair or fibers in the gastrointestinal tract, usually associated with underlying psychiatric disorders in females between 13 and 20 years old. Endoscopy, the gold standard for diagnosis, brings some additional advantages: sample taking, size reducing and, rarely, mass removal. This study shows that endoscopy can cause severe complications resulting in a surgical emergency

Trichobezoars in children: therapeutic complications

Trichobezoars are concretions formed by the accumulation of hair or fibers in the gastrointestinal tract, usually associated with underlying psychiatric disorders in females between 13 and 20 years old. Endoscopy, the gold standard for diagnosis, brings some additional advantages: sample taking, size reducing and, rarely, mass removal. This study shows that endoscopy can cause severe complications resulting in a surgical emergency

Use of adipose derived stem cells in Treacher Collins syndrome

Objective: Treacher Collins syndrome (TCS) is a rare congenital disorder of craniofacial development. TCS occurs with an incidence of 1:50,000, and more than 60% of TCS cases have no previous family history and arise as the result of de novo mutations. The high rate of de novo mutations, together with the extreme variability in the degree to which individuals can be affected, makes the provision of genetic counseling extremely complicated. Consequently, every case of TCS is unique and needs to be assessed individually. Patients with TCS frequently undergo multiple reconstructive surgeries from birth through adulthood, which rarely are fully corrective in the long-term. The nascent field of regenerative medicine offers the promise to improve some of these treatments. In particular, structural fat grafting (SFG) seems to be a good strategy not only to restore the normal volume and contour of the face, but also to provide a source of adipose-derived stem cells (ADSCs) with a multilineage differentiation potential. In this work, we present genetical analyses of ADSC affected by TCS. Materials and methods: ADSCs from were analyzed for their stemness properties and shared many characteristics with those of a healthy subject. Screening of the genome of the TCS patient using array-Comparative Genomic Hybridization allowed us to identify some chromosomal imbalances that are probably associated with TCS. Results: We found that some alterations, involving the TIMELESS gene, were usually associated with embryonic stem cells. Conclusions: With the aim to improve the final results, we need to consider combining knowledge of genetic alterations and expression profiles as a fundamental step before starting with surgical procedures

Le NbS-Nature-based Solutions per l’architettura e la città. L’approccio prestazionale alle tecnologie vegetate. Atti della conferenza 2023

La pubblicazione raccoglie gli atti della conferenza “Le NbS-Nature-based Solutions per l’architettura e la città. L’approccio prestazionale alle tecnologie vegetate”, organizzata il 13 ottobre 2023 presso l’Università Iuav di Venezia. Da anni la CE-Commissione europea investe risorse economiche crescenti nella ricerca e nelle politiche per le NbS essendo stati dimostrati innumerevoli vantaggi ambientali derivanti dal loro utilizzo, fra cui il contributo all’adattamento ai cambiamenti climatici. La stessa CE, però, rileva un importante ostacolo alla loro diffusione: “Le NbS hanno il potenziale per stimolare le economie locali e creare opportunità di business. Tuttavia, molte autorità pubbliche segnalano una gamma di difficoltà nell’utilizzo degli appalti pubblici per attuare progetti NbS. Sono necessarie maggiore coerenza politica e trasversalità nella definizione delle priorità a livello dell’Unione europea, così come una maggiore progettualità” (Castellari et al., 2021). Il focus dell’evento ha riguardato gli aspetti funzionali e prestazionali della vegetazione e dei sistemi tecnologici vegetati, con prevalente riferimento alle coperture a verde e alle facciate vegetate, nonché ai sistemi vegetati e drenanti impiegabili al suolo. Gli obiettivi della conferenza sono stati: diffondere la conoscenza scientifica e la cultura tecnica delle NbS e riunire in dibattito le competenze interdisciplinari che si interfacciano nelle attività di ricerca sulle NbS

In vitro comparative study on the mechanical behavior of Zirconia and Polyetheretherketone in applied dental sciences

OBJECTIVE: Recently, Zirconia and polyaryletherketone (PEEK) have attracted increasing interest as reliable and safe materials in dental applications, mainly because of their good biomechanical characteristics. The aim of this study was to investigate the response to different loads by prosthetic frameworks for supported fixed partial dentures (FPDs), thus simulating osseointegrated implants. MATERIALS AND METHODS: The specimens were divided into two groups (n= 5 each). Group A: FDPs in zirconia-ceramic; Group B: FDPs in PEEK-composite. These 2 groups were subjected to vertical loads so to evaluate structural deformation; then, they have been analyzed by scanning electron microscopy (SEM) at different magnifications. RESULTS: In tested samples, different types of mechanical failures have been observed. In Zirconia-specimens, chipping is the main failure noticed in this study, mostly in distal margins of the structure. Also, peek-specimens show failure and fracture. CONCLUSIONS: Zirconia and PEEK could be considered both good materials, but several investigations are needed to use these materials as an alternative to metals for fixed partial dentures