Retarding cement hydration by increasing temperature

Trabajo presentado a la 12th International Conference on Superplasticizers and Other Chemical Admixtures in Concrete, celebrada en Bejing (China) del 28 al 31 de octubre de 2018.Specific polymer structures at particular dosages have been identified to be able to delay cement hydration as temperature increases. The aim of the present work is to understand the underlying mechanisms involved behind this unexpected phenomenon. In particular, hydration kinetics of chemically admixed cement pastes at different temperatures have been related to the mineralogical changes in pastes, chemical composition of the pore solution and rheological properties. Results have demonstrated a dramatic increase in the low- concentration elements (Si, Al, Mg and Fe) in the pore solution of admixed samples hydrated at room temperature. At this temperature, nano-particles (polymer aggregates involving complexes and/or organoaluminates) have been detected. In contrast, nano-particles are not present at higher temperatures, when the delay of hydration is observed. This could lead to a higher amount of free polymer in the pore solution leading to a greater delay of silicates hydration.This research has been funded by the SP-SC 01-14 and SCCER-SoE projects

A multi-element psychosocial intervention for early psychosis (GET UP PIANO TRIAL) conducted in a catchment area of 10 million inhabitants: study protocol for a pragmatic cluster randomized controlled trial

Multi-element interventions for first-episode psychosis (FEP) are promising, but have mostly been conducted in non-epidemiologically representative samples, thereby raising the risk of underestimating the complexities involved in treating FEP in 'real-world' services

CUBETUG: A TETHERED SPACE TUG CONCEPT DEMONSTRATION FOR ACTIVE DEBRIS REMOVAL MISSIONS

In the last decade the collaboration between European industries, research institutions and space agencies led to the development of concepts and technologies to enable Active Debris Removal missions. Among all the proposed deorbiting strategies, harpoons and space nets are currently under extensive development; both employs medium-stiffness connection between a servicing vehicle and the debris, to tow the latter in the Earth atmosphere exploiting the propulsion system of the tug satellite. Much work has been done to date to develop and simulate the dynamics of tethered space tug manoeuvres, but despite the robust scientific background, only few experiments have been carried out on ground and in relevant environment, and none in full space environment. In this context, we propose a low-cost CubeSat mission that aims at demonstrating the feasibility of tethered space tug manoeuvres and validating all key technologies, such as tether deployer, tether dynamic instabilities countermeasures, chaser ACDS subsystem, and propulsion system for the re-entry manoeuvre. Moreover, the dynamics of both chaser and target will be closely monitored throughout the mission to assess the system dynamical stability

Unveiling Harriet Backer: ICP–OES study for the characterisation of the colour tubes from her original paint box

Abstract Micro-samples from 57 original paint tubes used between 1904 and 1909 by the Norwegian painter, Harriet Backer were studied with inductively coupled plasma–optical emission spectroscopy (ICP–OES). This accurate elemental characterisation of Backer’s original materials aims to fill several gaps in conservation science, painting conservation, and art technology. Firstly, it provides a novel and validated analytical method that can be applied to other painting materials. Secondly, ICP–OES offers scientific information about different oil colours from the late 19th to the early 20th century by Dr. Schoenfeld & Co., Düsseldorf, currently known as Lukas–Nerchau, whose archives were depleted during the Second World War. This work also lends new insights into the paintings of a renowned female Norwegian artist, whose painting materials have been little studied to date. ICP–OES results, coupled with a comprehensive, illustrated catalogue of paint tubes, will be instrumental for ongoing scientific investigations of this painter’s body of work

CONJUGATING EDUCATIONAL ACTIVITIES AND TECHNOLOGY DEVELOPMENT: THE EXAMPLE OF TED PROJECT

TED (Tethered Electromagnetic Docking) is a system proposed by a group of researchers and students of the University of Padova for close rendezvous and docking between spacecraft. It consists in a small tethered probe ejected by the chaser, reaching the proximity of the target with a controlled deployment, and then magnetically guided by a receiving electromagnet mounted on it. Because of the generated magnetic field, alignment and mating are possible; then, as the tether is rewound, the chaser is able to dock with the target. To perform a preliminary verification of TED, three groups of students have been involved in the project and contributed to the evaluation of its critical technologies in reduced gravity: in the framework of ESA “Drop your Thesis!” 2014 and 2016 campaigns the experiments FELDs and STAR focused on the test of the tether deployment and control, while PACMAN, in the framework of ESA “Fly Your Thesis! 2017” parabolic flights campaign, tested proximity operations by means of electromagnetic interactions. In this paper, a description of TED concept and its development roadmap is presented, introducing the critical technologies tested by FELDs, STAR and PACMAN experiments. The second part of the paper focuses on the educational outcomes of the three experiments, introducing statistics on (1) students participation, (2) scientific publication production, and (3) influence of the educational programs on the students’ career

AUTOPORT SYSTEM: A SUITE OF SENSORS AND MECHANISMS FOR MARS UAVS

In the last decades, Mars exploration has been carried out using orbiters, landers and rovers. In the future, these vehicles could be integrated with Unmanned Aerial Vehicles (UAV). Autoport is a student project of the University of Padua whose goal is to design, build and test a suite of sensors and mechanisms for autonomous Mars UAVs using COTS hardware. The features investigated are a battery recharge system, a docking mechanism and a navigation system. This paper describes the systems integrated by the Autoport Project and presents the preliminary test results conducted to validate the proposed architecture