Factorial experimentation on photodegradation of historical paper by polychromatic visible radiation

Quantification of the degradation behaviour of heritage objects is essential to manage the rate of degradation and hence optimise their lifetime. In this research, a 23 full factorial experiment was carried out to deepen the understanding of the photodegradation of historical rag paper induced by continuous polychromatic visible radiation. Oxygen concentration, relative humidity and illuminance were investigated as the three environmental factors of primary concern. The effects of these factors on the rate constant of change in diffuse reflectance and tristimulus discolouration were investigated by analysis of variance and multiple linear regression. The three main effects were found to contribute the most to the rate of photodegradation of historical paper, among which relative humidity played the most important role whereas illuminance played the least. This observation is likely to hold when extrapolating the experimental conditions to real conditions in collection storage and display.

eLaunceston Revisited – A Novel Regional Research Project from 1999

An historical paper from 1999 is republished because of its relevance to using digital communications to boost regional communities and their digital economies. Telstra Research Laboratories created a community website for Launceston Tasmania, with local stakeholder oversight, to test whether locally oriented information can increase the value of the Internet to existing users and make digital access more attractive to non-users.

Das historische Kartonmodell als Bildungsmedium

Paper models were a popular activity for children and at the same time a vehicle for educational content and political propaganda. Relevant historical paper models from the J. F. Schreiber publishing house were chosen to illustrate these purposes. The analysis of historico-cultural scenes, colonial paper models and kits from the era of the second world war show a clear picture of educational intentions. Through means of structured analysis of the paper models, possibilities for present didactics are illustrated.

Characterization of 17th Century Papers from Valvasor's Collection of the Zagreb Archdiocese

Valvasor's library is a unique example of a 17th-century personal library, which also includes over 7.300 prints. Today, it is part of the Metropolitan Library of the Archdiocese of Zagreb. In this study, the 17th-century papers in Valvasor's collection of unknown origin and composition were analysed. In order to determine the composition of these papers, a dual approach was used, by combining results obtained by non-destructive and destructive analyses from two sets of samples. On 144 paper sheets from Valvasor’s collection only non-destructive analyses were performed, whereas both, non-destructive and destructive analyses were performed on the second set of samples, 10 historical paper fragments, dating from 16th to 19th centuries. Among non-destructive analyses, surface imaging, measurements of thickness, surface pH and optical properties (brightness, yellowness, opacity, and gloss) of papers were carried out. Optical properties characterized the samples as yellowish, opaque papers without gloss. Destructive analyses performed on the historical paper fragments went deeper into their composition and properties. Initially, spot tests were performed to determine absorbency, an identify lignin and starch in paper samples. Of the elementary analyses, SEM-EDS and XRF analyses for the identification of inorganic elements and FTIR analysis to identify chemical bonds in fibers, fillers, and sizes were applied. Microscopic analyses were performed in two ways - the paper surface was imaged with a digital microscope and the morphological characteristics of the fibers were studied using an optical microscope. Different fibers and components were discovered in fragments of historical papers, thus confirming their presence in handmade paper over four centuries. The dominant fibers were flax and hemp, with a smaller proportion of cotton. Also, thick and thin light brown fibers resembling straw were observed. The presence of calcium containing components, probably calcium carbonate as filler, gelatin and alumn could be confirmed. Relating the composition of historical papers with surface pH and optical properties of papers enabled us to predict the composition of 17th-century papers in Valvasor's collection.

Can we expect an increased suicide rate due to Covid-19?

Human disasters come in all shapes and sizes including wars, terrorist violence, natural events, economic recessions and depressions as well as infection. As a species more fragile than we often allow, humans would be expected to adversely react to these types of disasters in terms of mental ill health and possibly suicidal behaviour leading to increased demands on the Mental Health services. This narrative historical paper examines relevant studies into how previous disasters affected mental health and suicidal behaviour. The characteristics of what is known of the current Covid-19 disease are analysed and compared to other types of disasters with a view to gaining some insight into what we might expect. Of all the types of disasters, economic recession appears most toxic. Mitigating the worst effects of recession appears to be protective. Particularly vulnerable groups are identified in whom we might expect an increase in suicidal behaviour.