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

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

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.

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

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.

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

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.

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

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.