Characterization of Nanoparticles in Ethanolic Suspension Using Single Particle Inductively Coupled Plasma Mass Spectrometry: Application for Cementitious Systems.

Single particle inductively coupled plasma mass spectrometry (spICP-MS) is a well-established technique to characterize the size, particle number concentration (PNC), and elemental composition of engineered nanoparticles (NPs) and colloids in aqueous suspensions. However, a method capable of directly analyzing water-sensitive or highly reactive NPs in alcoholic suspension has not been reported yet. Here, we present a novel spICP-MS method for characterizing the main cement hydration product, i.

The nucleation of C-S-H via prenucleation clusters.

The nucleation and growth of calcium-silicate-hydrate (C-S-H) is of fundamental importance for the strength development and durability of the concrete. However, the nucleation process of C-S-H is still not fully understood. The present work investigates how C-S-H nucleates by analyzing the aqueous phase of hydrating tricalcium silicate (CS) by applying inductively coupled plasma-optical emission spectroscopy as well as analytical ultracentrifugation.

Characterization data of reference materials used for phase II of the priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials".

A thorough characterization of base materials is the prerequisite for further research. In this paper, the characterization data of the reference materials (CEM I 42.5 R, limestone powder, calcined clay and a mixture of these three components) used in the second funding phase of the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented under the aspects of chemical and mineralogical composition as well as physical and chemical properties.

Charge regulated solid-liquid interfaces interacting on the nanoscale: Benchmarking of a generalized speciation code (SINFONIA).

Surface chemistry of mineral phases in aqueous environments generates the electrostatic forces involved in particle-particle interactions. However, few models directly take into account the influence of surface speciation and changes in solution speciation when the diffuse layer potential profiles of approaching particles overlap and affect each other. These electrostatic interactions can be quantified, ideally, through charge regulation, considering solution and surface speciation changes upon particle approach by coupling state-of-the-art surface complexation models for the two particle surfaces with a Poisson-Boltzmann type distribution of electrostatic potential and ions in the inter-particle space.

The Influences of Cement Hydration and Temperature on the Thixotropy of Cement Paste.

The rheological properties of fresh cement paste are highly influenced by a large number of parameters, among which the most important factors are the applied shear stress, and the shear history, the age of the sample and the temperature. The effects of these parameters on the yield stress (designated as structural limit stress in this work), the viscosity and the structural recovery rate (i.e.

Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials".

Two types of cements were selected as the reference cement in the priority program 2005 of the German Research Foundation (DFG SPP 2005). A thorough characterization of CEM I 42.5 R has been made in a recent publication [1].

Characterization data of reference cement CEM I 42.5 R used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials".

A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties.

A contribution to the characterization of the silicate-water interface - Part I: Implication of a new polished sample hydration technique.

The analysis of the atomic composition of the interface between tricalcium silicate (CS), the main compound of Ordinary Portland Cement, and surrounding solution is still a challenging task. At the same time, that knowledge is of profound importance for describing the basic processes during hydration. By means of Scanning Electron Microscopy (SEM) and Atom Probe Tomography (APT) we combine modern techniques in order to shed light on this topic in the present study.

A contribution to the characterization of the silicate-water interface - Part II: Atom Probe Tomography of tricalcium silicate.

This work explores the possibility to investigate the nanoscale cement-water interface by means of atom-probe tomography (APT). For this purpose, the main compound of Ordinary Portland Cement, tricalcium silicate, and its hydration product calcium-silicate-hydrate have been analyzed by APT. Of special interest was the surface of anhydrous and hydrated tricalcium silicate.

Substance P, bethanechol, 4-aminopyridine, and potassium antagonize the depressing effects of low-frequency stimulation, tetrodotoxin, procaine, and of magnesium on the field-stimulated guinea-pig vas deferens.

The twitch-response enhancing potencies of (the agonists) substance P, bethanechol, 4-aminopyridine and of potassium chloride were compared in the field-stimulated guinea-pig vas deferens. The agonists were tested after the twitching activity of the isolated organ had been reduced to an equal extent by (the antagonists) tetrodotoxin, procaine, magnesium chloride, and by decreased stimulation frequency. Further experiments were performed in the functionally denervated organ.