Μm Yr Research Articles

A method for dating early books and prints using image analysis

Many books and works of art printed over the centuries by hand-operated presses are undated or poorly dated. The use of classical methods of dating, such as matching watermarks in paper, has had limited success. Here, evidence is presented that the woodblocks and metal plates used in printing deteriorated at a constant rate, useful for time estimation. This change was measured in 2674 Renaissance prints. In successive editions, woodblock prints increased in the number of line breaks, whereas copperplate prints became paler. In both cases, the change was time dependent, not print dependent. For woodblocks, this can be explained by the aging of the wood, creating breaks in lines. For copperplates, image fading is a result of line thinning caused by surface erosion of the plate, not from compression by the printing press. The time dependency in copperplates is best explained by corrosion during plate storage, which was removed before each printing by polishing (erosion). The average rate of copperplate deterioration, 1–2 μm yr −1 , was estimated from the thinning rates of lines in two Italian prints and agrees with typical rates of atmospheric corrosion of copper. The print clock, if it applies generally, offers a relatively simple means of dating early books and prints.

PODZOLIZATION IN AEOLIAN SANDS, UNDERLAIN BY GLEYSOL FORMATION, DURING NINE MILLENNIA IN SOUTHWESTERN ESTONIA

An outcrop of Carbic Podzol on aeolian sand, underlain by Molli-Histic Gleysol on calcareous till of the last glaciation, was studied on the bank of the Lemmejogi River, SW Estonia. Molli-Histic Gleysol at depths of 342-380 cm formed as a result of pedogenesis within the Younger Dryas-Pre-Boreal during about 1500-3200 years at an average accumulation rate of organic carbon of 5.3-2.5 g m -2 yr -1 . The histic horizon formed during about 1000 years at a rate of 12-13 g m -2 yr -1 of organic carbon. Gleying of underlying till has led to slight textural changes but to some essential changes in mineral and chemical status. Gleysol was buried under the sediments of the Ancylus transgression about 9200-9000 years ago. Within the uppermost stratum, stratified sands have been reshaped by coastal winds after the retreat of the shoreline. Simultaneously with the development of the forest vegetation, pedogenesis started a little later than 9000 BP, and a unitary Carbic Podzol with the A-E-Bhs-Bs-BC-C sequence was formed. Organic C has accumulated at an average rate of 8.1 mg m -2 yr -1 cm -1 in the A-E-Bhs sequence, while the A- and Bhs-horizons were humus-accumulative and humus-illuvial in origin, respectively. Under the influence of R 2O3- and/or Ca-fulvic humus, total cheluviation and formation of the albic horizon has proceeded at a rate of 55 µm yr -1 . The solum of 180 cm, formed during about 9000 years, represents the result of the weathering and podzolization of the initial sand column of 171 cm, while the upward expansion in the uppermost 75 cm progressed at a rate of 6-7 µm m -2 yr -1 . As a consequence of interfraction changes, 5.6 g m -2 yr -1 of fine particles and 2.9 g m -2 yr -1 of chemical constituents have accumulated in the solum, although the A-E sequence is eluvial. Quartz and feldspars have mostly concentrated in fine sand. The increase in ore minerals and/or their eluvio-illuvial distribution has been induced by the weathering of pyroxenes and amphiboles. Against the background of total accumulativeness, the relationships of nonsiliceous substances are characterized by podzolic distribution. Due to human and some evident natural agents, a decrease in acidity and an increase in base exchange capacity and base saturation have taken place in the A-E-Bhs sequence of Carbic Podzol.

Corrosion behaviour of four high temperature engineering materials exposed to landfill gas engine flue gas

Four engineering materials commonly used in high-temperature applications were exposed to landfill gas engine flue gas for 25 days at 411°C. The flue gas was composed mostly of nitrogen and oxygen, although some carbon monoxide and hydrocarbons were detected together with low concentrations of hydrogen chloride gas and sulphur oxides. Hydrogen fluoride was not analysed, but, due to the nature of the fuel, may have been present at low levels. The materials tested were a carbon steel, a low alloy steel, a 12%Cr stainless steel and an austenitic stainless steel. Thin, protective films were formed on the 12%Cr and austenitic stainless steels, however, the corrosion products formed on carbon and low-alloy steels consisted of several layers, the outermost of which were extremely friable and non-adherent, especially on cooling from the flue gas working temperature. The maximum corrosion rate obtained was 70 μm yr–1 for carbon steel, which may be acceptable for a number of flue gas applications. The exposed coupons were examined using conventional techniques such as X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). The predominant scale formation mechanism controlling the corrosion appeared to be simple oxidation type reactions, however, the influence of HCl, as evidenced by the presence of akaganeite (β-FeO(OH)), was hypothesised. A model describing the corrosion mechanism is proposed in order to provide an improved life prediction capability for such flue gas environments.

Electrodeposition of PbO2 and Bi–PbO2 on Ebonex

Electrodeposition of PbO2 and Bi–PbO2 on Ebonex was carried out under various conditions, and the surfaces and coating/substrate interfaces examined by SEM, XPS and SIMS. Excellent adhesion to Ebonex was obtained with both crystalline and amorphous surfaces. Low plating temperatures resulted in dark grey, bright PbO2 and black, mirror-like Bi–PbO2 surfaces. Extrapolation of electrode lifetime test data indicated corrosion rates of 716 μm yr−1 for PbO2 and 158 μm yr−1 for Bi–PbO2.

Corrosion behaviour of four high temperature engineering materials exposed to landfill gas engine flue gas

Four engineering materials commonly used in high-temperature applications were exposed to landfill gas engine flue gas for 25 days at 411°C. The flue gas was composed mostly of nitrogen and oxygen, although some carbon monoxide and hydrocarbons were detected together with low concentrations of hydrogen chloride gas and sulphur oxides. Hydrogen fluoride was not analysed, but, due to the nature of the fuel, may have been present at low levels. The materials tested were a carbon steel, a low alloy steel, a 12%Cr stainless steel and an austenitic stainless steel. Thin, protective films were formed on the 12%Cr and austenitic stainless steels, however, the corrosion products formed on carbon and low-alloy steels consisted of several layers, the outermost of which were extremely friable and non-adherent, especially on cooling from the flue gas working temperature. The maximum corrosion rate obtained was 70 μm yr–1 for carbon steel, which may be acceptable for a number of flue gas applications. The exposed coupons were examined using conventional techniques such as X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). The predominant scale formation mechanism controlling the corrosion appeared to be simple oxidation type reactions, however, the influence of HCl, as evidenced by the presence of akaganeite (β-FeO(OH)), was hypothesised. A model describing the corrosion mechanism is proposed in order to provide an improved life prediction capability for such flue gas environments.

Dissolution of Mg-based Mg–Ni–Nd amorphous alloys in 3% NaCl solution

The hydrogen evolution testing method was used to determine the dissolution rates of melt-spun ribbons of seven fully amorphous Mg-based Mg–Ni–Nd alloys containing up to 15 at.% Nd and 20 at.%Ni in 3% NaCl solution saturated with Mg(OH)2. The results show that dissolution rates of these samples decrease with time of immersion to value as low as 38 μm yr−1 for Mg65Ni15Nd20. The surface of the corroded samples was found to be covered with Mg(OH)2 mainly. The results are compared with other Ni or Nd containing amorphous and microcrystalline Mg-based alloys and the effect of Ni and Nd on the dissolution rates of these amorphous alloys is discussed.

The influence of combustion-derived pollutants on limestone deterioration: 2. The wet deposition of pollutant species

The wet deposition of combustion-derived atmospheric pollutant species, on to freshly cut or diesel-smoked Portland and Monks Park limestone and marble samples, was carried out in a laboratory ‘wetting and drying’ salt spray chamber for 84 days. Along with the effect of CO 2-equilibrated de-ionized water at pH 5.5, for clean-rain base-line data, the relative effects of the Cl −, SO 4 2− and NO 3 − components (5.2, 8.6 and 3.0 mg l −1, respectively) of an artificial acid-rain solution were studied. Using spray run-off solution rates of 0.2 ml cm −2 day −1, and pH values of 5.5 and 3.8, the work was intended to determine the relative significance of water, anions and hydrogen ions. The effects of exposure were followed by analysis for calcium and anions in the run-off solutions, and by analysis for anions in the stone samples after exposure, weighing and crushing. From the total calcium reacted i.e. released from limestone to reaction ions and products, a theoretical limestone surface chemical recession rate was calculated. It was found that, at pH 5.5, water and solutions of individual anions gave similar recession rates within the range of 7.8 ± 1.8 and 11.5 ± 2.3 μm yr −1 for Portland and Monks Park limestones, respectively. At pH 3.8 the individual anion recession rates were increased to 11.1 ± 0.5 and 13.9 ± 0.5 μm yr −1, respectively, similar to the rates of 12.5 ± 1.6 and 13.8 ± 2.2 μm yr −1 for the mixed anion artificial acid rain solution on Portland and Monks Park limestones, respectively. Thus the water and hydrogen ion loading effects are significant, as well as the limestone type, but the nature of the anion is not, under the given wetting and drying regime. Further work showed that the increased resistance of marble over that of limestone, to calcium loss, is probably due to its much lower porosity. The results of smoke-coated samples suggested that any surface masking action depends upon particle size distribution.

Effects of acidic deposition on the erosion of carbonate stone — experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30° to horizontal at the five NAPAP materials exposure sites range from ∼ 15 to ∼ 30 μm yr −1 for marble, and from ∼ 25 to ∼ 45 μm yr −1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ∼ 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ∼ 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide (“clean rain”). These results are for marble and limestone slabs exposed at an angle of 30° from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60° or 85°. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at Washington, DC, and Steubenville, OH.

Studies on the effects of air pollution on limestone degradation in Great Britain

The CEGB and the Cathedrals Advisory Commission for England formed a Joint Working Party in 1985 to promote a research programme aimed at improving the understanding of the relationships between stone decay, atmospheric pollution and other factors. The programme has included exposure of limestone samples at York Minster and eight other sites in England and Scotland selected to give a mix of urban, marine and rural locations. All of the sites have comprehensive air pollution and meteorological monitoring and measurement of rainfall chemistry. At two sites samples have been fumigated with controlled levels of sulphur dioxide. Over all sites, there was a significant trend to increased weight loss with increase in average sulphur dioxide concentration, but a negative trend with total nitrogen oxides and with nitrogen dioxide. For sample exposures longer than 200 days, the sulphur dioxide dependence at the inland Liphook fumigation site was about half that found near the coast at Littlehampton. There was no significant trend to increase weight loss with total rainfall amount for the complete data set, but the analysis was dominated by the very wet Scottish site, which experienced the lowest average concentrations of air pollutants. A theoretical model for the chemical dissolution of rainwashed limestone has been derived from consideration of the ion and mass balances between the incident rain water and run-off water. The model has been fitted to the measured loss rates from the stonework field trials. With the exception of the very wet Scottish site, the difference between the stone loss rate, calculated from the model, and the mean measured loss rate for any particular exposure was generally smaller than the variation between the triplicate samples. Variation in the dry deposition velocity between sites and exposure periods does not appear to have been a very significant factor, and no residual effect due to the concentrations of nitrogen oxides was found. The natural solubility of limestone in water was the dominant term in describing the stone loss, and neutralization of the rainfall acidity the least significant. The volume of the intercepted rainfall and the variation in the pH of the run-off water with rainfall intensity have been identified as the two most significant terms which require more precise quantification. The data from the inland fumigation site used in the model predict a stone loss due to sulphur dioxide in the air of less than 1 μm yr −1 surface recession per ppb SO 2.

Corrosion of construction metals under simulated acid rain/fog conditions with high salinity

Corrosion of 1,312 specimens of five common construction metals were examined in a salt-spray chamber under simulated conditions of acid rain/fog with high salinity. When specimens were exposed to a condition simulating the acid rain/fog during summer in Hong Kong, i.e. pH 3.5, 1% of salt and 35 °C, the average corrosion rates were 735, 330, 2, 97 and 9 µm yr−1, respectively, for mild steel, galvanized steel, stainless steel 304, red brass and aluminum. Relative effects of pH, salt concentration and temperature on the corrosion of these five metals were analyzed based on tests conducted at nine designed conditions. For the first four metals, the corrosion rate appears to increase linearly with the increase of ‘acidity’, salinity and temperature, according to regression analysis. Corrosion rate of SS 304 is almost independent of salinity and temperature, but is slightly affected by pH. Red brass is more susceptible than SS 304, but its susceptibilities to pH and salinity are one order of magnitude lower than those of mild steel and galvanized steel. Mild steel is about five times more susceptible to pH than galvanized steel; whereas the latter is about three times more susceptible to salinity than the former. Aluminum's corrosion rate increases as pH decreases; however, the effects of salinity and temperature are inconclusive.

Corrosion of austenitic and martensitic stainless steels in flowing 17Li-83Pb alloy

With regard to the behaviour of 316 L stainless steel at 400°C in flowing anisothermal 17Li-83Pb the mass transfer suffered by this steel appears to be quite important without noticeable influence of constant or cyclic stress. Evaluation made from solution-annealed specimens leads to a corrosion rate of approximately 30 μm yr−1 at steady state to which a depth of 25 μm has to be added to take into account the initial period phenomena. On the other hand, with semi-stagnant 17Li-83Pb at 400° C, the mass transfer of 316 L steel appears to be lower and more acceptable after a 3000-h exposure; but long-time kinetics data have to be achieved in order to see if that better behaviour is persistent and does not correspond to a longer incubation period. As for the martensitic steels their corrosion rate at 450°C in the thermal convection loop TULIP is constant up to 3000 h and five times lower than that observed for 316 L steel in the same conditions.