Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
PLoS One ; 18(6): e0287057, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37310969

RESUMO

Cognitive styles are commonly studied constructs in cognitive psychology. The theory of field dependence-independence was one of the most important cognitive styles. Yet in the past, its measurement had significant shortcomings in validity and reliability. The theory of analytic and holistic cognitive styles attempted to extend this theory and overcome its shortcomings. Unfortunately, the psychometric properties of its measurement methods were not properly verified. Furthermore, new statistical approaches, such as analysis of reaction times, have been overlooked by current research. The aim of this pre-registered study was to verify the psychometric properties (i.e., factor structure, split-half reliability, test-retest reliability, discriminant validity with intelligence and personality, and divergent, concurrent and predictive validity) of several methods routinely applied in the field. We developed/adapted six methods based on self-report questionnaires, rod-and-frame principles, embedded figures, and hierarchical figures. The analysis was conducted on 392 Czech participants, with two data collection waves. The results indicate that the use of methods based on the rod-and-frame principle may be unreliable, demonstrating no absence of association with intelligence. The use of embedded and hierarchical figures is recommended. The self-report questionnaire used in this study showed an unsatisfactory factor structure and also cannot be recommended without futher validation on independent samples. The findings also did not correspond with the original two-dimensional theory.


Assuntos
Personalidade , Pensamento , Humanos , Reprodutibilidade dos Testes , Inteligência , Cognição
2.
Am J Occup Ther ; 77(3)2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37326571

RESUMO

IMPORTANCE: Approximately 7% to 30% of children contend with handwriting issues (HIs) in their school years. However, research studies to define and quantify HIs, as well as practical assessment tools, are lacking. OBJECTIVE: To confirm the validity and reliability of two screening scales for HIs: the Handwriting Legibility Scale (HLS) and the Concise Assessment Scale of Children's Handwriting (BHK). DESIGN: Structural equation modeling (SEM) and confirmatory factor analysis (CFA) of five different models were used to examine the construct and discriminant validity of both scales. Furthermore, internal consistency and interrater agreement were evaluated. The association among scales, grades, and children's self-evaluation was also explored. SETTING: Elementary schools and state counseling centers in the Czech Republic. PARTICIPANTS: On a voluntary basis, 161 children from elementary schools and state counseling centers in the Czech Republic were enrolled. The variable of children with typical handwriting development versus HIs was missing for 11 children. Thus, for discriminant validity analysis, 150 data records from children were used. OUTCOMES AND MEASURES: The HLS and BHK were used to evaluate the handwriting quality of the transcription task. The Handwriting Proficiency Screening Questionnaires for Children was used for children's self-evaluation. RESULTS: The study confirmed the validity and reliability of the shortened BHK and HLS. A strong relationship was found between the BHK and HLS, grades, and children's self-evaluation. CONCLUSIONS AND RELEVANCE: Both scales are recommended for occupational therapy practice worldwide. Further research should focus on developing standards and providing sensitivity studies. What This Article Adds: Both the HLS and the BHK are recommended for occupational therapy practice. Practitioners should also take the child's well-being into consideration in handwriting quality assessment.


Assuntos
Escrita Manual , Terapia Ocupacional , Criança , Humanos , Psicometria , Reprodutibilidade dos Testes , República Tcheca
3.
Materials (Basel) ; 15(2)2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35057355

RESUMO

Sixteen localities were involved in a broad study, resulting in the classification of the indoor corrosivity of metals considered in the ISO 11844 standard, especially lead. Recently, lead has been added to the standard as a metal specifically sensitive to volatile organic compounds such as acetic acid. Data on one-year exposure in museum depositories and exhibition spaces, archives, libraries, and churches show that the currently valid lead corrosivity categories are not correctly defined. The obtained data allowed for the proposal of new realistic ranges of indoor corrosivity categories for lead. The exposure program was also used to validate techniques for determining the corrosion degradation of metal coupons. Mass increase and mass loss techniques were supplemented with the galvanostatic reduction technique and the measurement of color changes. The study identified the limitations of the mass gain method. Not only is the galvanostatic reduction technique applicable for silver and copper coupons, but the build-up of reducible lead corrosion products depends on air corrosivity. CIELab color-change measurement has proven to be a simple and easy-to-apply method for monitoring the corrosivity of indoor atmospheres with regard to lead. A more reliable response is provided by the determination of color change after 3 months of exposure rather than after one year.

4.
Materials (Basel) ; 16(1)2022 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-36614565

RESUMO

Indoors, volatile organic acids can play an important role in the degradation process of many materials. Considering this fact, metal corrosion coupons of copper, silver, lead, and zinc were exposed to different climatic conditions of 18 locations for 3, 12, and 30 months, and their corrosion rates were evaluated based on mass loss, as recommended by the ISO 11844 standard. The corrosion rates were compared with in situ colorimetric measurements to validate the colorimetry as a simple tool for estimating the corrosivity of an environment. The results have shown good correlation between the methods for two metals: silver and lead, confirming the possibility of non-destructive monitoring of their corrosion by measurement of color changes.

5.
Materials (Basel) ; 13(24)2020 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-33322657

RESUMO

Restoration treatment, specimen preparation or mass loss measurements on coupons made of lead require a reliable process of dissolution of corrosion products. In this study, several types of model corrosion products with compositions representative of those found on real objects were prepared and characterized. Ten solutions were then thoroughly tested in interval cleaning experiments, regarding the efficiency of removal of the corrosion products, corrosivity towards bare lead, and remnants left on the surface. The solution recommended in the current version of the ISO 8470 standard was found to be improper for the cleaning of both historical artefacts and corrosion coupons due to its inability to remove sulfide corrosion products and the risk of surface contamination and staining. A solution of 20% hydrochloric acid is the best choice for the preparation of lead coupons before exposure or for evaluation of mass loss of exposed samples because its somewhat higher corrosivity towards metallic lead is tolerable for these applications. Rochelle salt solution was found to be optimal for the cleaning of historical artefacts free of sulfide corrosion products due to the lowest corrosivity. None of these alternative solutions leave remnants on the surface and they are efficient at laboratory temperature.

6.
Materials (Basel) ; 12(24)2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31817271

RESUMO

The phase composition and portion of individual phases in advanced high-strength steels (AHSS) CP1000 and DP1000 was studied by complementary microscopic and diffraction techniques. CP1000 and DP1000 steel grades have a high strength-to-density ratio and they are used in many applications in the automotive industry. The microstructure of the CP1000 "complex phase" steel consists of ferrite, bainite, martensite and a small amount of retained austenite. DP1000 is a dual phase steel, which has a structure of a ferritic matrix with islands of martensite and a minor amount of retained austenite. The influence of selected etchants (Nital, LePera, Beraha I, Nital followed by metabisulfite, Nital followed by LePera, and Nital followed by Beraha I) on the microstructure image is described. X-ray diffraction, neutron diffraction and light optical, scanning and transmission electron microscopy were used in this work for advanced characterization of the microstructure and phase composition. The information provided by each technique is critically compared.

7.
Mater Sci Eng C Mater Biol Appl ; 70(Pt 1): 112-120, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27770870

RESUMO

Flowered coatings composed by ZnO crystals were successfully electrodeposited on Zn-Mg alloys. The distinct coatings morphologies were found to be dependent upon the solid interfaces distribution, with the smaller number of bigger flowers (ø 46µm) obtained on Zn-Mg alloy containing 1wt.% Mg (Zn-1Mg) contrasting with the higher number of smaller flowers (ø 38µm) achieved on Zn-Mg alloy with 2wt.% Mg (Zn-2Mg). To assess the in vitro behaviour of these novel resorbable materials, a detailed evaluation of the degradation behaviour, in simulated physiological conditions, was performed by electrochemical impedance spectroscopy (EIS). The opposite behaviours observed in the corrosion resistances resulted in the build-up of distinct corrosion layers. The products forming these layers, preferentially detected at the flowers, were identified and their spatial distribution disclosed by EDS and Raman spectroscopy techniques. The presence of smithsonite, simonkolleite, hydrozincite, skorpionite and hydroxyapatite were assigned to both corrosion layers. However the distinct spatial distributions depicted may impact the biocompatibility of these resorbable materials, with the bone analogue compounds (hydroxyapatite and skorpionite) depicted in-between the ZnO crystals and on the top corrosion layer of Zn-1Mg flowers clearly contrasting with the hindered layer formed at the interface of the substrate with the flowers on Zn-2Mg.


Assuntos
Ligas/química , Materiais Revestidos Biocompatíveis/química , Magnésio/química , Óxido de Zinco/química , Zinco/química , Corrosão , Espectroscopia Dielétrica , Galvanoplastia , Espectrometria por Raios X , Análise Espectral Raman
8.
Faraday Discuss ; 180: 361-79, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25912828

RESUMO

In situ time-lapse optical microscopy was used to examine the microstructural corrosion mechanisms in three zinc-magnesium-aluminium (ZMA) alloy coated steels immersed in 1% NaCl pH 7. Preferential corrosion of MgZn(2) lamellae within the eutectic phases was observed in all the ZMA alloys followed by subsequent dissolution of Zn rich phases. The total extent and rate of corrosion, measured using time-lapse image analysis and scanning vibrating electrode technique (SVET) estimated mass loss, decreased as Mg and Al alloying additions were increased up to a level of 3 wt% Mg and 3.7 wt% Al. This was probably due to the increased presence of MgO and Al(2)O(3) at the alloy surface retarding the kinetics of cathodic oxygen reduction. The addition of 1 × 10(-2) mol dm(-3) Na(3)PO(4) to 1% NaCl pH 7 had a dramatic influence on the corrosion mechanism for a ZMA with passivation of anodic sites through phosphate precipitation observed using time-lapse image analysis. Intriguing rapid precipitation of filamentous phosphate was also observed and it is postulated that these filaments nucleate and grow due to super saturation effects. Polarisation experiments showed that the addition of 1 × 10(-2) mol dm(-3) Na(3)PO(4) to the 1% NaCl electrolyte promoted an anodic shift of 50 mV in open circuit potential for the ZMA alloy with a reduction in anodic current of 2.5 orders of magnitude suggesting that it was acting primarily as an anodic inhibitor supporting the inferences from the time-lapse investigations. These phosphate additions resulted in a 98% reduction in estimated mass loss as measured by SVET demonstrating the effectiveness of phosphate inhibitors for this alloy system.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...