439 research outputs found
Composition and structure of an 18-year-old 5M KOH-activated ground granulated blast-furnace slag paste
The main hydration products were C-A-S-H(I), present in both inner (Ip) and outer product (Op), and a Mg-Al layered double hydroxide (LDH), present only in the Ip. The composition of C-A-S-H(I) was the same in Op and Ip. Reduced scatter in the data with age suggests a tendency towards compositional homogeneity. The mean length of the aluminosilicate anions in the C-A-S-H(I) increased with age. The layer spacings of the C-A-S-H(I) and Mg-Al LDH had not changed significantly with age. The Mg/Al ratio of the LDH was about 2.6 and had not changed between 1 and 18 years
HERWIG 6.5 Release Note
A new release of the Monte Carlo program HERWIG (version 6.5) is now
available. The main new features are: support for the Les Houches interface to
matrix element generators; additional SM and MSSM Higgs processes in lepton
collisions; additional matrix elements for the spin correlation algorithm; a
new version of the ISAWIG interface; interface to the MC@NLO program for heavy
quark, Higgs and vector boson production in hadron collisions. boson pair
production in hadron collisions. This is planned to be the last major release
of Fortran HERWIG. Future developments will be implemented in a new C++ event
generator, HERWIG++
The mechanism of supplementary cementitious materials enhancing the water resistance of magnesium oxychloride cement (MOC): A comparison between pulverized fuel ash and incinerated sewage sludge ash
Magnesium oxychloride cement (MOC) pastes incorporating supplementary cementitious materials (SCMs) including pulverized fuel ash (PFA) and incinerated sewage sludge ash (ISSA) were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with energy dispersive X-ray spectrometry (EDX). The result showed that the mechanism of PFA and ISSA in improving the water resistance of MOC paste is similar, even though the molar ratios of the hydration product in the ISSA-incorporated paste and the PFA-incorporated paste were different. The active phases in PFA or ISSA could react with MgO and produce an amorphous phase (amorphous magnesium aluminosilicate gel), which was interspersed with Phase 5 and changed the morphology of Phase 5 to fibroid or lath-like phases. These fibroid or lath-like phases interlocked with each other and also connected with the amorphous phase in the matrix to form a stable compact structure. Therefore, the water resistance of MOC was improved. The ISSA-blended MOC paste had higher water resistance compared to the PFA-blended MOC, which may be due to the different chemical composition of amorphous phase and the dissolved phosphorus from ISSA
Quantitative study of hydration of C3S and C2S by thermal analysis. Evolution and composition of C-S-H gels formed
This research is part of a European project (namely, CODICE project), main objective of which is modelling, at a multi-scale, the evolution of the mechanical performance of non-degraded and degraded cementitious matrices. For that, a series of experiments were planned with pure synthetic tri-calcium silicate (C3S) and bi-calcium silicate (C2S) (main components of the Portland cement clinker) to obtain different calcium–silicate–hydrate (C–S–H) gel structures during their hydration. The characterization of those C–S–H gels and matrices will provide experimental parameters for the validation of the multi-scale modelling scheme proposed. In this article, a quantitative method, based on thermal analyses, has been used for the determination of the chemical composition of the C–S–H gel together with the degree of hydration and quantitative evolution of all the components of the pastes. Besides, the microstructure and type of silicate tetrahedron and mean chain length (MCL) were studied by scanning electron microscopy (SEM) and 29Si magic-angle-spinning (MAS) NMR, respectively. The main results showed that the chemical compositions for the C–S–H gels have a CaO/SiO2 M ratio almost constant of 1.7 for both C3S and C2S compounds. Small differences were found in the gel water content: the H2O/SiO2 M ratio ranged from 2.9 ± 0.2 to 2.6 ± 0.2 for the C3S (decrease) and from 2.4 ± 0.2 to 3.2 ± 0.2 for the C2S (increase). The MCL values of the C–S–H gels, determined from 29Si MAS NMR, were 3.5 and 4 silicate tetrahedron, for the hydrated C3S and C2S, respectively, remaining almost constant at all hydration periods
Psychometric analysis of the scale for the predisposition to the occurrence of adverse events in nursing care provided in ICUS
OBJECTIVE: to present the result of the validity and reliability studies concerning the Scale for the Predisposition to the Occurrence of Adverse Events (EPEA).
METHOD: construct validity was based on Principal Components Analysis.
RESULTS: reliability verified through Cronbach's alpha indicated good reliability (structure α=0.80; process α=0.92).
CONCLUSION: based on its psychometric indicators, the EPEA can be considered a valid measure to assess the attitudes of nurses in relation to factors that potentially lead to the occurrence of adverse events in ICUs
Tips for Teachers of Evidence-based Medicine: Clinical Prediction Rules (CPRs) and Estimating Pretest Probability
Reliability and validity of the Japanese version of the Resilience Scale and its short version
<p>Abstract</p> <p>Background</p> <p>The clinical relevance of resilience has received considerable attention in recent years. The aim of this study is to demonstrate the reliability and validity of the Japanese version of the Resilience Scale (RS) and short version of the RS (RS-14).</p> <p>Findings</p> <p>The original English version of RS was translated to Japanese and the Japanese version was confirmed by back-translation. Participants were 430 nursing and university psychology students. The RS, Center for Epidemiologic Studies Depression Scale (CES-D), Rosenberg Self-Esteem Scale (RSES), Social Support Questionnaire (SSQ), Perceived Stress Scale (PSS), and Sheehan Disability Scale (SDS) were administered. Internal consistency, convergent validity and factor loadings were assessed at initial assessment. Test-retest reliability was assessed using data collected from 107 students at 3 months after baseline. Mean score on the RS was 111.19. Cronbach's alpha coefficients for the RS and RS-14 were 0.90 and 0.88, respectively. The test-retest correlation coefficients for the RS and RS-14 were 0.83 and 0.84, respectively. Both the RS and RS-14 were negatively correlated with the CES-D and SDS, and positively correlated with the RSES, SSQ and PSS (all p < 0.05), although the correlation between the RS and CES-D was somewhat lower than that in previous studies. Factor analyses indicated a one-factor solution for RS-14, but as for RS, the result was not consistent with previous studies.</p> <p>Conclusions</p> <p>This study demonstrates that the Japanese version of RS has psychometric properties with high degrees of internal consistency, high test-retest reliability, and relatively low concurrent validity. RS-14 was equivalent to the RS in internal consistency, test-retest reliability, and concurrent validity. Low scores on the RS, a positive correlation between the RS and perceived stress, and a relatively low correlation between the RS and depressive symptoms in this study suggest that validity of the Japanese version of the RS might be relatively low compared with the original English version.</p
A method for predicting the alkali concentrations in pore solution of hydrated slag cement paste
Evidence for local particle acceleration in the first recurrent galactic cosmic ray depression observed by Solar Orbiter. The ion event on 19 June 2020
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