Search results for "Hard"

Cellular basis of abnormal tissue hardening in lung fibrosis examined with atomic force microscopy

2010

Electrokinetic Properties which Control the Coagulation of Silicate Cement Suspensions during Early Age Hydration

1998

The coagulation of cement particles during early age hydration has been previously identified as the first step of the setting and hardening of cement pastes. By hydrating Ca3SiO5and a silicate-rich clinker under controlled conditions, a correlation between the coagulation of the suspensions and the electrokinetic properties of particles is established. The zeta potential, and hence the surface charge, of particles in suspension depends on the calcium content of the medium. At low concentrations of Ca2+, the zeta potential of Ca3SiO5particles, calcium silicate hydrate (C–S–H), and clinker is negative (<−30 mV) and the suspensions are well dispersed. A strong coagulation occurs at intermedia…

Evaluation of the effect of home bleaching agents on surface microhardness of different glass-ionomer cements containing hydroxyapatite

2017

Background Home bleaching agents may exert some negative effects on surface hardness of restorative materials such as glass-ionomer cements (GICs). Since some studies have shown that some components such as hydroxyapatite (HA), as a bioactive glass, can improve the mechanical properties of dental materials, the effect of bleaching agents on surface hardness of GICs containing hydroxyapatite is questionable. This study was designed to evaluate the effect of home bleaching agents on the surface hardness of two different commercially available GICs containing hydroxyapatite. Material and methods 80 disk-shaped specimens were made from two different GICs, including resin modified glass-ionomer …

Formation of the C−S−H Layer during Early Hydration of Tricalcium Silicate Grains with Different Sizes

2005

Portland cement is a mixture of solid phases which all react with water. Tricalcium silicate (Ca3SiO5) is its main component and is often used in model systems to study cement hydration. It is generally recognized that setting and hardening of cement are due to the formation, by a dissolution-precipitation process, of a calcium silicate hydrate (C-S-H) on anhydrous grains during Ca3SiO5 hydration. The purpose of this paper is to study the effect of Ca3SiO5 particle size on the nucleation-growth process of C-S-H. An experimental study of the rate of hydration by using different grain sizes under controlled conditions has been performed. The experimental data have been compared with results o…

Influenza della natura dei nutrienti azotati sull’attività di due ceppi di lievito nella vinificazione di uve bianche prodotte in Sicilia

2008

Check in–check out intervention for supporting pupils’ behaviour: effectiveness and feasibility in Finnish schools

2018

Check In–Check Out (CICO) is a support programme for students with externalising problem behaviours. This study implemented in Finland is one of the first reports on the application of CICO in the European context. An experimental, multiple-baseline, single-case design is used to examine the effects of the CICO intervention on the problem behaviour and appropriate behaviour of three general education primary school pupils. The similarity of the observation data and the information provided in daily report card (DRC) are investigated to gauge the validity of the DRC assessments. The fidelity and social validity of the intervention are also analysed. CICO reduced problem behaviour in all pupi…

Exploiting seeding of random number generators for efficient domain decomposition parallelization of dissipative particle dynamics

2013

Abstract Dissipative particle dynamics (DPD) is a new promising method commonly used in coarse-grained simulations of soft matter and biomolecular systems at constant temperature. The DPD thermostat involves the evaluation of stochastic or random forces between pairs of neighboring particles in every time step. In a parallel computing environment, the transfer of these forces from node to node can be very time consuming. In this paper we describe the implementation of a seeded random number generator with three input seeds at each step which enables the complete generation of the pairwise stochastic forces in parallel DPD simulations with minimal communication between nodes.

A Comparative Analysis of the Electrophilicity of Organic Molecules between the Computed IPs and EAs and the HOMO and LUMO energies

2007

[EN] The electrophilicity index, omega, of a series of substituted ethylenes used in some relevant organic reactions has been evaluated from the ionization potential JP) and the electron affinity (EA) computed by vertical ionization at the B3LYP/aug-cc-PVTZ level. The corresponding electrophilicity values are well correlated with those obtained from the HOMO and LUMO energies of the neutral molecules. The good linear correlation found between omega(I,A) and omega(H,L)(LBS), and between omega(H,L)(LBS) and omega(H,L)(SBS) allows to confirm the use of the easily available B3LYP/6-31G(*) HOMO and LUMO energies to obtain reasonable values of the global electrophilicity index of organic molecule…

Solution Processed Micro- and Nano-Bioarrays for Multiplexed Biosensing

2012

This Feature article reports on solution dispensing methodologies which enable the realization of multiplexed arrays at the micro- and nanoscale for relevant biosensing applications such as drug screening or cellular chips.

Dynamics of Colloidal Hard Spheres in Thin Aqueous Suspension Layers—Particle Tracking by Digital Image Processing and Brownian Dynamics Computer Sim…

1993

Abstract A new experimentally simple technique is introduced for studying dynamical properties of hard sphere colloids in thin aqueous suspension layers by light-microscopy observation supported by computer-aided digital image processing. The thickness of the layers of the colloidal samples confined between two smooth glass plates is accurately adjusted by monodisperse "spacer" spheres which are larger than the diffusing spheres. Tracking of single particles in concentrated phases is accomplished using fluorescence light microscopy where a few dyed particles are mixed with the undyed colloidal spheres of the same size. First results are presented for the self-diffusion coefficient—(i) in ve…