Abstract:In the present work we determined the chromatic coordinates (L*,a*,b*) and ultrasound propagation speeds on the three spatial planes (V x ,V y ,V z ) of three ornamental granites (Aqueduct of Segovia, Spain) before, during, and after being subjected to 70 cycles of two types of accelerated ageing (typical of cold regions): a) freezing/thawing and cooling/heating (T1), and b) freezing/thawing and cooling/heating + salt crystallization (T2). A multivariate technique (Canonical Biplot) was applied to the data obt… Show more
“…The stone was cut into cubic samples (6 cm × 6 cm × 6 cm) and was subjected to the following accelerated aging treatments under controlled conditions: T1: Cycles of freezing/thawing and cooling/heating (–20°C to 110°C) in a simulation chamberT2: A combined freezing/thawing and cooling/heating + phosphate crystallization.…”
Section: Methodsmentioning
confidence: 99%
“…There is no specific guideline in T2, the samples were immersed in a 1% solution of hydrated sodium phosphate (Na 3 PO 4 ⋅10H 2 O) instead of distilled water …”
Section: Methodsmentioning
confidence: 99%
“…One of the aesthetic parameters of a building stone is its color, which strongly contributes to its ornamental value. Similar to other properties, monitoring of color is important for assessing the effectiveness of a treatment and to judge the changes that occur when using artificial aging tests . To predict the expected decaying processes that occur in stone materials, it is very necessary to anticipate problems that may arise from accelerated aging.…”
Section: Introductionmentioning
confidence: 99%
“…Similar to other properties, monitoring of color is important for assessing the effectiveness of a treatment and to judge the changes that occur when using artificial aging tests. [1][2][3][4][5][6][7] To predict the expected decaying processes that occur in stone materials, it is very necessary to anticipate problems that may arise from accelerated aging. To address this, currently climatic chambers are being used for carrying out aging experiments under controlled conditions.…”
A new methodology has been applied to the experimental data obtained about a white siliceous conglomerate from Zamora (Spain), which was subjected to 25 cycles of 2 types of aging [freezing/thawing with cooling/heating (T1) and freezing/thawing with cooling/heating + phosphate crystallization (T2)]. Our model (multivariate Gaussian subspatial regression) allows the behavior and prediction of the chromatic coordinates (L*,a*,b*), including more than 25 cycles, to be analyzed. This model is much more flexible than classical models as it allows multiple variable combinations to be predicted in a dynamic way. The final result showed that the conglomerate experiences darkening, yellowing, and reddening, as the number of cycles increase and that the darkening is much less pronounced in T2 due to phosphate crystallization.
“…The stone was cut into cubic samples (6 cm × 6 cm × 6 cm) and was subjected to the following accelerated aging treatments under controlled conditions: T1: Cycles of freezing/thawing and cooling/heating (–20°C to 110°C) in a simulation chamberT2: A combined freezing/thawing and cooling/heating + phosphate crystallization.…”
Section: Methodsmentioning
confidence: 99%
“…There is no specific guideline in T2, the samples were immersed in a 1% solution of hydrated sodium phosphate (Na 3 PO 4 ⋅10H 2 O) instead of distilled water …”
Section: Methodsmentioning
confidence: 99%
“…One of the aesthetic parameters of a building stone is its color, which strongly contributes to its ornamental value. Similar to other properties, monitoring of color is important for assessing the effectiveness of a treatment and to judge the changes that occur when using artificial aging tests . To predict the expected decaying processes that occur in stone materials, it is very necessary to anticipate problems that may arise from accelerated aging.…”
Section: Introductionmentioning
confidence: 99%
“…Similar to other properties, monitoring of color is important for assessing the effectiveness of a treatment and to judge the changes that occur when using artificial aging tests. [1][2][3][4][5][6][7] To predict the expected decaying processes that occur in stone materials, it is very necessary to anticipate problems that may arise from accelerated aging. To address this, currently climatic chambers are being used for carrying out aging experiments under controlled conditions.…”
A new methodology has been applied to the experimental data obtained about a white siliceous conglomerate from Zamora (Spain), which was subjected to 25 cycles of 2 types of aging [freezing/thawing with cooling/heating (T1) and freezing/thawing with cooling/heating + phosphate crystallization (T2)]. Our model (multivariate Gaussian subspatial regression) allows the behavior and prediction of the chromatic coordinates (L*,a*,b*), including more than 25 cycles, to be analyzed. This model is much more flexible than classical models as it allows multiple variable combinations to be predicted in a dynamic way. The final result showed that the conglomerate experiences darkening, yellowing, and reddening, as the number of cycles increase and that the darkening is much less pronounced in T2 due to phosphate crystallization.
“…The Canonical biplot method has been used in the conservation of historical buildings and monuments (Varas et al, 2005), in civil engineering (Iñigo et al, 2005;Iñigo et al, 2013) and, in the case of foods, in the study of margarines (Rui Alves and Beatriz Oliveira, 2003), but no reference has been found regarding its application to the characterization of cheeses using volatile compounds as variables.…”
SUMMARY:The canonical biplot method (CB) is used to determine the discriminatory power of volatile chemical compounds in cheese. These volatile compounds were used as variables in order to differentiate among 6 groups or populations of cheeses (combinations of two seasons (winter and summer) with 3 types of cheese (cow, sheep and goat's milk). We analyzed a total of 17 volatile compounds by means of gas chromatography coupled with mass detection. The compounds included aldehydes and methyl-aldehydes, alcohols (primary, secondary and branched chain), ketones, methyl-ketones and esters in winter (WC) and summer (SC) cow's cheeses, winter (WSh) and summer (SSh) sheep's cheeses and in winter (WG) and summer (SG) goat's cheeses. The CB method allows differences to be found as a function of the elaboration of the cheeses, the seasonality of the milk, and the separation of the six groups of cheeses, characterizing the specific volatile chemical compounds responsible for such differences.KEYWORDS: Canonical biplot; Cheeses; Seasonality; Type of milk (cow, sheep, goat); Volatiles RESUMEN: Papel del método biplot canónico en el estudio de compuestos volátiles en quesos de composición variable. El método biplot canónico (CB) se utiliza para determinar el poder discriminatorio de compuestos químicos volátiles en queso. Los compuestos volátiles se utilizan como variables con el fin de diferenciar entre los 6 grupos o poblaciones de quesos (combinaciones de dos temporadas (invierno y verano) con 3 tipos de queso (vaca, oveja y cabra). Se analizan un total de 17 compuestos volátiles por medio de cromatografía de gases acoplada con detección de masas. Los compuestos incluyen aldehídos y metil-aldehídos, alcoholes (primarios de cadena, secundaria y ramificada), cetonas, metil-cetonas y ésteres. Los seis grupos de quesos son, quesos de vaca de invierno (WC) y verano (SC); quesos de oveja de invierno (WSh) y verano (SSh) y quesos de cabra de invierno (WG) y verano (SG). El método CB permite la separación de los seis grupos de quesos y encontrar las diferencias en función del tipo y estacionalidad de la leche, caracterizando los compuestos químicos volátiles específicos responsables de tales diferencias.
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