scholarly journals Colour Stabilisation of Surface of Four Thermally Modified Woods with Saturated Water Vapour by Finishes

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3373
Author(s):  
Zuzana Vidholdová ◽  
Gabriela Slabejová
Keyword(s):  
Water Vapour ◽  
Wood Species ◽  
Treated Wood ◽  
European Beech ◽  
Yellowness Index ◽  
Saturated Water ◽  
Surface Finishes ◽  
Acrylic Polyurethane ◽  
Saturated Water Vapour ◽  
Thermally Treated

This paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native wood, and thermally treated wood, with saturated water vapour. In the experiment, alder, European beech, Paper birch, and Norway maple wood were thermally treated at a temperature of 135 °C under saturated water vapour for six hours. Three various types of surface finishes (acrylic-polyurethane, polyacrylic and aldehyde resin, and alkyd resin) were applied onto the wood surfaces. The colours of the surfaces in the system, CIE L*a*b* (lightness, coordinates a* and b*, chroma and hue angle), were measured during finishing and natural ageing behind glass windows in an interior, over a period of 60 days. The results show that the changes in the yellowness index, and the total colour differences after the application of individual surface finishes to wood species, changed because of sunlight exposure. Moreover, it is clear that different wood finishes behaved differently on all of the wood species. An analysis is presented in this paper.

Synthetic Preparation and Properties of Ettringite

2018 ◽  
Vol 760 ◽  
pp. 49-54
Author(s):  
Marcela Fridrichová ◽  
Dominik Gazdič ◽  
Jana Mokrá ◽  
Karel Dvořák
Keyword(s):  
Thermal Analysis ◽  
Water Vapour ◽  
Molecular Water ◽  
Free Calcium ◽  
X Ray Diffraction ◽  
Laboratory Environment ◽  
X Ray ◽  
Subsequent Transformation ◽  
Saturated Water ◽  
Saturated Water Vapour

This paper deals with the verification of the possibility of preparing synthetic ettringite in a way of direct addition of aluminum sulfate and calcium hydroxide as an alternative to the hydration of yeelimite. The stability of the resulting system was studied using the X-ray diffraction (XRD) and differential thermal analysis (DTA) in two different environments, namely in a laboratory environment and the environment of saturated water vapour. The evaluations of X-ray diffraction analysis and thermal analysis show that in the ettringite sample stored in the laboratory environment, evaporation of molecular water and subsequent transformation of ettringite into metaettringite or monosulfate can occur over time. Conversely, exposition of saturated water vapour environment can lead to saturation of the system by free calcium ions due to the slow dissociation of calcium carbonate, and thereby increase the amount of ettringite at the expense of gypsum and aluminum amorphous phase. To verify the above, it is recommended long-term monitoring of samples exposed in monitored environments.

scholarly journals An Evaluation of Fourteen Oxygen Analysers for Use in Patient Breathing Circuits

1986 ◽  
Vol 14 (4) ◽  
pp. 431-436 ◽  
Author(s):  
A. H. Ilsley ◽  
W. B. Runciman
Keyword(s):  
Nitrous Oxide ◽  
Water Vapour ◽  
Response Times ◽  
Sudden Change ◽  
Adequate Response ◽  
Saturated Water ◽  
Cause Of Error ◽  
Line Oxygen ◽  
Oxygen Analyser ◽  
Saturated Water Vapour

Fourteen in-line oxygen monitors designed for use in patient breathing circuits were assessed to determine the lifespans of their sensors when exposed to oxygen, their response times to a sudden change in oxygen concentration from 30% to 0%, the effects of exposure to nitrous oxide, and the effects of some agents and conditions commonly encountered in anaesthetic breathing systems by exposing the sensors repeatedly for three two-hour periods to 1% halo thane, 2% enflurane, saturated water vapour at 37 °C, 5 % carbon dioxide, or a continuous pressure of 40 mmHg. Under the conditions of this study all sensors but one exceeded the manufacturers’ claimed lifespans, and all had clinically adequate response times to sudden hypoxic changes. None had significantly altered responses when repeatedly exposed to nitrous oxide. Water vapour was the most common cause of error for both polarographic and galvanic cell sensors, although some errors occurred with each of the test conditions; errors from all causes occurred evenly throughout the lifespans of both types of sensor. The incidence of over-read errors was approximately equal to that of under-read errors. However, clinically potentially dangerous over-read errors of greater than 6% oxygen did not occur in any of the sensors, with the exception, on some occasions, of the Datex Oxygen Analyser when exposed to saturated water vapour at 37°C.

Comparison of Beam Damage of Hydrated Biological Specimens in High-Pressure Scanning Electron Microscopy and Low-Temperature Scanning Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 386-387
Author(s):  
A.N. Farley ◽  
A. Beckett ◽  
J.S. Shah
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Pressure ◽  
Low Temperature ◽  
Water Vapour ◽  
Beam Voltage ◽  
Saturated Water ◽  
Temperature Scanning ◽  
Scanning Electron ◽  
Saturated Water Vapour

High Pressure Scanning Electron Microscopy (HPSEM) is a technique in which biological materials are viewed close to their natural state in a saturated water vapour environment and at ambient temperatures. The absence of chemical or cryogenic fixation in this technique can offer considerable advantages in the reduction of preparative artifacts in labile specimens but it is also necessary to consider the effects of the electron beam interaction with the specimen. A comparative study has been undertaken with low temperature scanning electron microscopy (LTSEM) to evaluate the relative damage rates in the labile specimen Narcissus sp. . The results are compared with those expected from theoretical models of the beam-specimen interaction developed by other workers. Full details of the theory and practice of HPSEM have been presented elsewhere.Fresh, untreated perianth segments of Narcissus sp. were excised and examined in HPSEM at a saturated water vapour pressure of 1716 Pa, with a beam voltage of 10 kV and beam current of approximately 100 pA. The beam dose rate was therefore approximately 15 MJ.Kg−1s−1 over the scanned area. Fully frozen hydrated specimens were prepared for LTSEM and examined in an uncoated condition at a beam voltage of 3kV to reduce charging artifacts. No metal films were applied to the LTSEM specimens since this would artificially increase the thermal conductivity of the surface.

scholarly journals Long-term Observation of Yeelimite Clinker Hydration in Environment of Saturated Water Vapour

2016 ◽  
Vol 151 ◽  
pp. 94-99 ◽  
Author(s):  
Jana Mokrá ◽  
Karel Kulísek ◽  
Dominik Gazdič ◽  
Marcela Fridrichová
Keyword(s):  
Water Vapour ◽  
Saturated Water ◽  
Long Term Observation ◽  
Saturated Water Vapour

scholarly journals Thermodynamic Stability of Ettringite Formed by Hydration of Ye’elimite Clinker

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Marcela Fridrichová ◽  
Karel Dvořák ◽  
Dominik Gazdič ◽  
Jana Mokrá ◽  
Karel Kulísek
Keyword(s):  
Water Vapour ◽  
Mineralogical Composition ◽  
Fluidized Bed Combustion ◽  
X Ray Diffraction ◽  
Ambient Temperatures ◽  
Saturated Water ◽  
Complex Process ◽  
The Stability ◽  
Saturated Water Vapour

In order to save limited natural resources by utilising industrial by-products, this paper focuses on an entirely new application of fluidized bed combustion fly ash (FBCFA) into Portland composite cements. It is not currently used because undesirable ettringite, 3CaO·Al2O3·3CaSO4·32H2O, is formed during the hydration of FBCFA. Although the stability of ettringite has been the subject of much research, the solution is not yet fully clear. Ettringite is generally considered to be stable up to a temperature of 110°C; however, some investigators claimed that ettringite may already decompose at even ambient temperatures. To prove these statements, ettringite was prepared by the hydration of ye’elimite, 3CaO·3Al2O3·CaSO4, and the system stored at laboratory temperature in two environments: in laboratory settings and in an environment of saturated water vapour. The mineralogical composition of ettringite was long term (up to 160 days of hydration) and was analysed by X-ray diffraction (XRD) and differential thermal analysis (DTA). The hydration of ye’elimite is a relatively complex process. Only approximately 30% of ettringite was formed under laboratory conditions that appeared to gradually convert into metaettringite. Within an environment of saturated water vapour, we observed the conversion of ettringite into monosulfate. Original ye’elimite was indicated as the dominant phase of both storages.

scholarly journals Potential use of nir and visible spectroscopy to analyze chemical properties of thermally treated wood

2018 ◽  
pp. 0-0 ◽  
Author(s):  
Elaine Cristina Lengowski ◽  
Graciela Inês Bolzon de Muñiz ◽  
Umberto Klock ◽  
Silvana Nisgoski
Keyword(s):  
Chemical Properties ◽  
Treated Wood ◽  
Visible Spectroscopy ◽  
Potential Use ◽  
Thermally Treated

Innovative Alkyd Emulsion Composition Enhanced With Nanosize Iron Oxides for the Protection of Thermally Treated Wood in Outdoor Conditions

2021 ◽  
Author(s):  
◽  
Errj Sansonetti
Keyword(s):  
Iron Oxide ◽  
Surface Energy ◽  
Wood Surface ◽  
Treated Wood ◽  
Thermal Modification ◽  
Alkyd Emulsion ◽  
Water Based ◽  
Outdoor Weathering ◽  
Iron Oxide Pigments ◽  
Thermally Treated

Wood has great potential for uses in outdoor conditions, but it can be easily degraded due to the action of environmental factors (solar radiation, moisture, fungi, insects, etc.). The protection of wood is therefore a very actual research topic, and it is also the object of this work. The main goal of this Doctoral Thesis is to obtain a water-based alkyd paint formulation in the form of emulsion and to optimize its composition with necessary additives, in particular, with nanosized red iron oxide pigments which can protect the decorative qualities of thermally treated wood (TTW) during outdoor exposure. In the literature review, the main factors responsible for the degradation of wood and their effect on the structure and properties of wood are summarized. The chemistry of coatings for the protection of wood and the challenges that are faced in reformulation of paints, due to more stringent regulations which limit the use of organic solvents and promote greener alternatives, like water-based paint formulations, are considered. In Europe, this is stated by the Directive 2004/42/EC of the European Parliament on the limitation of emissions of volatile organic compounds (VOC) from decorative paints and varnishes. In the first part of the experimental section, the optimal composition of the alkyd emulsion and the effects of additives on the film properties have been investigated. The different chemo-physical properties of thermally treated wood compared with those of untreated wood have been also evaluated. After thermal modification, wood becomes more hydrophobic and this has been confirmed from the changes of the surface energy of thermally treated wood: the polar component of the surface energy decreases with increasing temperature of thermal modification. In the second part of the experimental section, artificial and outdoor weathering tests have been done to determine the suitable concentration of red iron oxide nanoparticles which can give better protection against photodegradation. Results show that red iron oxide pigments at a concentration of 8 % in alkyd emulsion are efficient to protect the wood surface against discoloration. During the outdoor weathering test, the performance of alkyd emulsion has been compared with that of the solvent-based formulation. Results confirm that the water-based alkyd emulsion gives better protection of the thermally treated wood surface than the solvent-based formulation, thus confirming that the replacement of organic solvent with water gives a product with equivalent or better properties for the protection of thermally treated wood in outdoor conditions.

scholarly journals Combined bound water and water vapour diffusion of Norway spruce and European beech in and between the principal anatomical directions

Holzforschung ◽  
2011 ◽  
Vol 65 (6) ◽  
pp. 819-828 ◽  
Author(s):  
Walter Sonderegger ◽  
Manuele Vecellio ◽  
Pascal Zwicker ◽  
Peter Niemz
Keyword(s):  
Diffusion Coefficient ◽  
Steady State ◽  
Water Vapour ◽  
Diffusion Coefficients ◽  
Bound Water ◽  
European Beech ◽  
Unsteady State ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion ◽  
Water Vapour Resistance

Abstract The combined bound water and water vapour diffusion of wood is of great interest in the field of building physics. Due to swelling stresses, the steady-state-determined diffusion coefficient clearly differs from the unsteady-state-determined diffusion coefficient. In this study, both diffusion coefficients and the water vapour resistance factor of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) were investigated for the principal anatomical directions (radial, tangential and longitudinal) and in 15° steps between these directions. The values were determined with the cup method as the basic principle. The unsteady-state-determined diffusion coefficient is, independent of the direction, about half that of the steady-state-determined diffusion coefficient. Both diffusion coefficients are about two to three times higher for spruce than for beech. They are up to 12 times higher in the longitudinal direction than perpendicular to the grain for spruce, and up to 15 times higher for beech. With increasing moisture content, the diffusion coefficients exponentially increase. The water vapour resistance factor shows converse values to the diffusion coefficients.

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