Search results for "Solid"

Water Dynamics at the Solid-Liquid Interface to Unveil the Textural Features of Synthetic Nanosponges.

2020

A Fast-Field-Cycling NMR investigation was carried out on a set of polyurethane cyclodextrin nanosponges, in order to gain information on their textural properties, which have been proven to be quite difficult to assess by means of ordinary porosimetric techniques. Experiments were performed on both dry and wet samples, in order to evaluate the behavior of the “non-exchangeable” C-bound 1H nuclei, as well as the one of the mobile protons belonging to the skeletal hydroxyl groups and the water molecules. The results acquired for the wet samples accounted for the molecular mobility of water molecules within the channels of the nanosponge network, leading back to the possible pore size distrib…

Comparison between mercury intrusion porosimetry and nuclear magnetic resonance relaxometry to study the pore size distribution of limestones treated…

2019

Abstract Pore-space properties, such as pore-size distribution and connected porosity, are relevant factors in the evaluation of the performance of a consolidation treatment. In this study, two different techniques – Mercury Intrusion Porosimetry (MIP) and Nuclear Magnetic Resonance Relaxometry (NMRR) – were adopted to study the compatibility and the efficacy of a new consolidation product for limestones. This work aims at comparing and combining data obtained by MIP and NMRR; to confirm the relationship between the quantitative results of MIP and the qualitative ones of NMRR, a calibration which leads to correlate T2 distribution and pore size distribution has been applied. Experimental re…

Pore structure and water transfer in Pietra d’Aspra limestone: A neutronographic study

2020

Neutron radiography (NR) was here applied to study the effects of two different commercially available consolidants on the water absorption properties in a particular type of limestone (biocalcarenite), known as Pietra d’Aspra stone, which is one of the most extensively used lithotypes in Sicilian Baroque buildings. Our attention was mainly focused on the evaluation, using a fast and nondestructive visualization of water motion through capillarity, of the effectiveness of such layers as consolidating agents in view of preserving and maintaining both old and modern structures. The biocalcarenite was treated with nanosilica (Nano Estel®) and nanolime (CaLoSil®) by brushing it until full satur…

International student mobility in Southern-Latin Europe: beyond the EU logics, towards a new space

2018

This paper discusses international student mobility (ISM) in Southern-Latin Europe, specifically Italy, Portugal, and Spain, analysing the inflow of international students as reflected in the UNESCO, OECD and European Commission databases. Only recently Italy, Portugal and Spain, as latecomers, have become more actively involved in ISM dynamics. This trend has been a response to EU pressures to internationalization, instrumented through the consolidation of the Bologna process and the need to build a common space of higher education. The analysis shows that at the intra-European level Italy, Portugal and Spain share similar ISM patterns; however, in the global context other logics shape ISM…

Nuestros prejuicios, señor Krauze

2006

Quantum chemical modelling of point defects in KNbO3 perovskite crystals

2000

Abstract We present results of semi-empirical quantum chemical calculations for several perovskite KNb x Ta 1−x O 3 (KTN) solid solutions, as well as point intrinsic defects – F centers and hole polarons bound to K vacancy – in KNbO 3 . Method of the intermediate neglect of the differential overlap (INDO) was combined with typically 320-atom supercells and atomic geometry optimization. Analysis of the optimized atomic and electronic structure has clearly demonstrated that several nearest Nb atoms substituting for Ta in KTaO 3 – unlike Ta impurities in KNbO 3 – reveal the self-ordering effect, which probably triggers the ferroelectricity observed in KTN. We predict co-existence of one-site (…

Mechanical pre-treatment for separation of bio-waste from municipal solid waste: case study of district in Latvia

2019

Characterization of refuse derived fuel production from municipal solid waste: the case studies in Latvia and Lithuania

2020

Abstract The authors determined the morphological composition of refuse derived fuel (RDF) produced in Latvia and Lithuania by manually sorting. The parameters of RDF (moisture, net calorific value, ash content, carbon, nitrogen, hydrogen, sulphur, chlorine, metals) was determined using the EN standards. Comparing obtained results with data from literature, authors have found that the content of plastic is higher but paper and cardboard is lower than typical values. Results also show that the mean parameters for RDF can be classified with the class codes: Net heating value (3); chlorine (3); mercury (1), and responds to limits stated for 3rd class of solid recovered fuel. It is recommended …

Education, Work and Life

2018

In this chapter, I will study the relationship between education and working life from a few viewpoints. First, I will examine how everyday working life has changed and how education has to change. Second, I will depict how the practices of both education and the working world can and should be researched in terms of the theory of practice architectures. Third, I will come back to reflect on the relationships between work, education and life. The work that people do has increasingly been immaterialized. Working life has been detached from material production which is more and more automated and robotically driven. According to a Swiss professor Schwab (2015, 2016), we have already moved int…

Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems

2011

The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Rea…