scholarly journals Ion Transport and Precipitation Kinetics as Key Aspects of Stress Generation on Pore Walls Induced by Salt Crystallization

2018 ◽  
Vol 120 (3) ◽  
Author(s):  
A. Naillon ◽  
P. Joseph ◽  
M. Prat
Soft Matter ◽  
2019 ◽  
Vol 15 (22) ◽  
pp. 4562-4569 ◽  
Author(s):  
Antoine Naillon ◽  
Pierre Joseph ◽  
Marc Prat

In contrast with the classical picture where the generation of stress on pore walls due to salt crystallisation is analysed by a compressive stress using the concept of crystallization pressure, we report a mechanism leading to the generation of a local tensile stress.


2017 ◽  
Vol 2 ◽  
pp. 108-118 ◽  
Author(s):  
Robert Flatt ◽  
Nevin Aly Mohamed ◽  
Francesco Caruso ◽  
Hannelore Derluyn ◽  
Julie Desarnaud ◽  
...  

Salt crystallization is accepted to represent one of the major causes for the degradation of building and ornamental stone. As such, it has attracted the attention of researchers, who over the years have progressively unraveled most mechanisms involved in salt damage. Despite this, many questions subsist about how to quantitatively predict damage or its progression, and in particular how to relate performance on site to that in laboratory tests. In this context, a new RILEM TC has been started with the objective of defining laboratory tests that deliver more reliable predictions of field behavior. One deliverable of this TC, is to provide a theoretical insight into this question based on recent progress on the understanding of salt damage. This paper presents a summary of this work, highlighting key aspects relating to crystallization pressure, chemo-mechanics and transport. Implications are more specifically discussed in relation to existing accelerated tests in an attempt to better define the type of field exposure that they may best represent. A simple conceptual model for the development of salt damage is introduced. During an initial “induction” phase, transport of ions and accumulation of salt in the porous materials occurs without causing detectable damage until a critical point, termed “damage onset” is reached. Beyond this point, during the “propagation phase”, the material degrades increasingly. The implications of these two phases are discussed in relation to the selection of appropriate salt weathering tests and conservation interventions.


Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4434 ◽  
Author(s):  
Felix Grases ◽  
Antonia Costa-Bauza

Phytate (myo-inositol hexaphosphate, InsP6) is an important component of seeds, legumes, nuts, and whole cereals. Although this molecule was discovered in 1855, its biological effects as an antinutrient was first described in 1940. The antinutrient effect of phytate results because it can decrease the bioavailability of important minerals under certain circumstances. However, during the past 30 years, researchers have identified many important health benefits of phytate. Thus, 150 years have elapsed since the discovery of phytate to the first descriptions of its beneficial effects. This long delay may be due to the difficulty in determining phytate in biological media, and because phytate dephosphorylation generates many derivatives (InsPs) that also have important biological functions. This paper describes the role of InsP6 in blocking the development of pathological calcifications. Thus, in vitro studies have shown that InsP6 and its hydrolysates (InsPs), as well as pyrophosphate, bisphosphonates, and other polyphosphates, have high capacity to inhibit calcium salt crystallization. Oral or topical administration of phytate in vivo significantly decreases the development of pathological calcifications, although the details of the underlying mechanism are uncertain. Moreover, oral or topical administration of InsP6 also leads to increased urinary excretion of mixtures of different InsPs; in the absence of InsP6 administration, only InsP2 occurs at detectable levels in urine.


2001 ◽  
Vol 120 (5) ◽  
pp. A532-A532
Author(s):  
R LARSEN ◽  
M HANSEN ◽  
N BINSLEV ◽  
A MERTZNIELSEN
Keyword(s):  

Author(s):  
Tatsuhiko Sato ◽  
Koji Niita ◽  
Norihiro Matsuda ◽  
Shintaro Hashimoto ◽  
Yosuke Iwamoto ◽  
...  

Pneumologie ◽  
2016 ◽  
Vol 70 (07) ◽  
Author(s):  
JJ Salomon ◽  
T Albrecht ◽  
H Scheuermann ◽  
I Baumann ◽  
MA Mall

2017 ◽  
pp. 79-112
Author(s):  
Paola Ramassa ◽  
Costanza Di Fabio

This paper aims at contributing to financial reporting literature by proposing a conceptual interpretative model to analyse the corporate use of social media for financial communication purposes. In this perspective, the FIRE model provides a framework to study social media shifting the focus on the distinctive features that might enhance web investor relations. The model highlights these features through four building blocks: (i) firm identity (F); (ii) information posting (I); (iii) reputation (R); and (iv) exchange and diffusion (E). They represent key aspects to explore corporate communication activities and might offer a framework to interpret to what degree corporate web financial reporting exploits the potential of social media. Accordingly, the paper proposes metrics based on this model aimed at capturing the interactivity of corporate communications via social media, with a particular focus on web financial reporting. It tries to show the potential of this model by illustrating an exploratory empirical analysis investigating to what extent companies use social media for financial reporting purposes and whether firms are taking advantage of Twitter distinctive features of interaction and diffusion.


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