A study of mechanical properties of papers exposed to various methods of accelerated ageing. Part I. The effect of heat and humidity on original wood-pulp papers

The damage to historical documents and books caused by the acidic character of paper is often manifested as a complete loss of their mechanical properties. Deacidification and restoration of archived paper objects require knowledge of the long-term behaviour of paper before and after repair actions. Our study was focused on the investigation of mechanical properties (tensile strength, stretch, tensile index, zero-span tensile strength, folding endurance) of original papers (one alkaline and three different acidic samples) exposed to five methods of dry-heat and moist-heat accelerated ageing. The degree of paper deterioration upon ageing was significantly influenced by the temperature and relative humidity, along with the intrinsic chemistry of the individual paper samples. The correlation matrix evaluated at a 95% confidence level for tensile strength, stretch, tensile index and zero-span showed linear correlations between these mechanical properties for all the paper samples. However, a linear dependence of folding endurance on zero-span tensile strength was found only for alkaline paper, which revealed the highest resistance to the accelerated ageing tests. In addition, the concentration of paramagnetic semiquinone species in the acidic lignin-containing paper samples was monitored by Electron paramagnetic resonance spectroscopy.     

Effective biocide to prevent microbiological contamination during PEG impregnation of wet archaeological iron-wood artefacts

A new conservation process was developed for archaeological iron-wood artefacts. Metal part protection was achieved by adding a corrosion inhibitor (Hostacor IT^®) in the polyethylene glycol (PEG) soaking solutions. Nevertheless, a significant microbiological growth was observed in the baths and around the objects. From the different soaking solutions, 23 bacterial strains and 12 strains of filamentous fungi were isolated. Adding compatible biocide has been absolutely essential to allow the PEG and Hostacor IT^® to be effective. Among biocides tested, Dowicide^®A that contains sodium o-phenylphenate is the most efficient. As shown by electrochemical measurements (corrosion potential, intensity and polarization resistance), this biocide does not destabilize the formation of protective film created by Hostacor IT^®. There is no competition of adsorption between Hostacor IT^® and Dowicide^®. In the presence of Dowicide^®, Hostacor IT^® acts more quickly and in a significant way.At the concentration of 3000 ppm, Dowicide^® is effective to protect the aqueous solutions of PEG 400+ Hostacor IT^® from the development of the selected microorganisms. Adding the biocide at the beginning of the object impregnation was the most effective way to prevent bacterial and fungal growth. Tests in real conditions showed that after two months of impregnation, solutions reminded clear and no biofilm was observed around artefacts.     

Preservation of aged paper using borax in alcohols and the supercritical carbon dioxide system

Selecting an appropriate paper deacidification agent is very important for the deacidification of paper. The use of three deacidification agents (i.e., iso-butylamine, calcium propionate, and borax) is studied for the deacidification of paper using the immersion treatment by investigating the paper surface pH, alkaline residue, paper whiteness, strength, and other performance indicators. Results show the deacidification by borax solution not only results in the promotion of a proper pH range, high level of alkali reserves, and ignorable influence to paper appearance, but also to the enhancement of the mechanical intensities of paper even after artificial aging. Supercritical carbon dioxide (CO₂SCF), as a solvent system, is used in the deacidification of acidic papers using the borax solution of water and alcohol. CO₂SCF improved the deacidification process by significantly improving the pH value and the base residual value. The borax in supercritical fluids can be better combined with cellulose hydroxyl to improve the mechanical properties of paper substantially. The treatment of borax in CO₂SCF could be an alternative for acidic papers. Aside from improving the pH and depositing a sufficient alkaline residual, CO₂SCF also strengthens the mechanical properties of treated papers.     

Titanium dioxide thin film: Environmental control for preservation of paper-art-works

Due to sensitivity of historic papers and their conservation importance, it is necessary to produce appropriate environment condition for preservation purposes. TiO₂ nanoparticles have been evaluated for multiple applications in the conservation of paper because of TiO₂ nanoparticles special characteristics for UV filtration, decomposing of air pollutants and their antifungal and antibacterial properties. Firstly, TiO₂ nanoparticles synthesized in sol-gel process, and then have been coated on glass surface with spray-pyrolysis method. Then, coated glass used for preparing display box for protecting paper-art-works. Also, non-coated glass was used as a blank sample and assessments have been done on the filter paper (Whatman^®) as a standard for paper-art-works. Temperature, humidity and light accelerated aging were done on samples in both coated and uncoated boxes. Results showed more tension strength and lower oxidation of paper and also, lower growth of fungi and bacteria in coated glassy box. Furthermore, madder dyed papers into coated box showed lower fading after UV exposure.     

Deacidification of paper using dispersions of Ca(OH)2 nanoparticles in isopropanol. Study of efficiency

The efficiency of a recently described non-aqueous method for paper deacidification using Ca(OH)₂ nanoparticles in isopropanol was evaluated by pH and colorimetric measurements and by the analysis of the degree of polymerization (DP). Samples of plain paper and paper with iron gall ink were tested. The results were compared with non treated samples and samples submitted to the traditional treatment with saturated aqueous Ca(OH)₂ solution. By comparing the two conservation methods, the aqueous one shows higher neutralization reaction kinetics than the non-aqueous one. The iron gall ink samples maintain their coloration closer to the original after the non-aqueous Ca(OH)₂ nanoparticles treatment, in contrary to the aqueous treatment that changes the ink aesthetics considerably. Artificial aging tests revealed a general increase in the aging stability of deacidified paper samples. The Ca(OH)₂ nanoparticles treatment can be an alternative for papers who can not be treated by the classical aqueous treatment, e.g. papers with water soluble components.     

Early detection of fungal biomass on library materials

Library materials are susceptible to fungal deterioration. The paper constituents of archival materials are subjected to harmful physical and chemical processes as they are slowly consumed by fungi. Remediation of fungal contamination can be costly and risk further damage to fragile or previously degraded materials. Early detection of fungal growth would permit the use of relatively noninvasive treatments to remediate fungal contamination of artifacts before visible or lasting damage has occurred. Current methods used for the detection of microbial biomass, such as colony counts, microscopic biovolume estimation, and ergosterol analysis are expensive, time consuming, or are inappropriate for use with fungi. Beta-N-acetylhexosaminidase (EC 3.2.1.52) activity provides a rapid and reliable means of fungal detection on a variety of cultural heritage materials. Adapted for use on archival materials, fluorogenic 4-Methylumbelliferyl (MUF) labeled substrate N-acetyl-Beta-D-glucosamine (NAG) was used to detect fungal beta-N-acetylhexosaminidase activity. The fluorescence generated by minute quantities of fungi was quickly detected at an early stage of growth. The sensitivity of the assay was comparable to other biochemical techniques. The fluorometric assay was well-suited for early detection of fungal biomass on paper and assessment of the effectiveness of common remediation practices.     

New cellulosic titanium dioxide nanocomposite as a protective coating for preserving paper-art-works

We investigate the TiO₂ role in the inherent protection of paper works of art to protect them against damaging effect of ultraviolet radiation, pollutant gasses, mold and bacteria. In this study a cellulosic nanocomposite of TiO₂ were used as protective coating on the surface of paper fibers. This layered nanocomposite can act as a consolidate materials too. Furthermore, to determine how well paper works screen objects from the damaging effects, two accelerated aging mechanisms due to light and heat are discussed. Results show good stability of papers with nanocomposite coating. Also, a good light stability was shown in the colored paper that treated with this nanocomposite. Furthermore, to demonstrate the degree of antifungal properties of coated papers, papers were treated with two common molds and the good preventive effect of coated paper against molds is described.     

Use of ZnO nanoparticles for protecting oil paintings on paper support against dirt,fungal attack,and UV aging

Zinc oxide nanoparticles were prepared and used for surface treatment of oil paintings painted on paper supports. The prepared coating mixture containing 2% of ZnO nanoparticles showed excellent transparency. The effect of coating on protecting the paper support and paintings against microbial attack by Trichoderma reesei and Aspergillus niger, dirt accumulation, and UV aging was studied. Coatings containing ZnO nanoparticles enhanced the durability of linseed oil-based paintings toward UV aging regarding the change in color. Coatings containing ZnO nanoparticles improved resistance to microbial attack when subjected to inoculums containing T. reesei or A. niger fungi. In addition, coatings containing ZnO nanoparticles reduced accumulation of dirt on oil paintings when left in open air for 6 months; cleaning of paintings was quite easy compared to the non-coated paintings or those coated with the varnish without ZnO nanoparticles.     

<Emphasis Type="Italic">Minerva</Emphasis> and the Development of Science (Policy) Studies

This article analyzes the transformation of Minerva from an intellectual towards a scholarly journal by making use of bibliometric methods. The aim is to provide some empirical insights that help to understand what properties of the journal changed in the course of this transformation process. Minerva was one of the first journals that reflected on science and its role in society and science policy in particular. Analyzing the development of the journal sheds light on the emergence of science (policy) studies and on Minerva’s role as a forerunner in this field. In a first step, the methods will be described. The second section provides some empirical results of the publication output of Minerva and its relations to other journals in the field. The empirical findings are put into a broader perspective in the concluding third section.     

Consolidation and protection by nanolime: Recent advances for the conservation of the graffiti,Carceri dello Steri Palermo and of the 18th century lunettes,SS. Giuda e Simone Cloister,Corniola (Empoli)

Nanolime dispersed in 2-propanol was extensively used for the consolidation of wall paintings. The knowledge of the advances of this methodology dealing with all the possible effects associated with the nanolime new material in conservation is fundamental to assess and improve the technique. In this paper, four different dispersions of Ca(OH)₂ nanoparticles were characterised by Small Angle X-rays Scattering technique (SAXS) and Transmission Electron Microscopy (TEM) in order to achieve information on size, shape, polydispersity, agglomeration, and crystal structure (by SAED patterns) of the particles. Once characterised, the dispersions were tested in two different case studies, the Carceri dello Steri in Palermo with their graffiti and the 18th century lunettes at the SS. Giuda e Simone Cloister, Corniola (Empoli) with their lime-based mural paintings. The treated samples were characterised in relationship to either their morphology and surface chemical composition by Scanning Electron Microscopy coupled with Energy Dispersive X-rays spectroscopy (SEM-EDX), or their water absorption and mechanical properties (resistance to material abrasion). The results obtained showed that all the dispersions were nanometrically structured and their application succeeded in recovering the mechanical properties of the painting or graffito layers, not altering their permeability to water and keeping perfectly the wall transpiration. However, the dispersions constituted of the nanoparticles obtained via a synthesis able to control size and shape of the Ca(OH)₂ particles resulted in a better performance in situ, even if the differences found by SAXS and TEM were slight.     

A note on Chinese Bamboo paper: The impact of modern manufacturing processes on its photostability

Papermaking has a special place in the cultural heritage of China. Papers made from different types of plant fibers were, and are still used for particular applications. Bamboo paper is a handmade paper that has been traditionally used for book printing and restoration of ancient paper objects since antiquity in China, whereas Xuan paper, the subject of recent previous study, is used for traditional Chinese calligraphy and painting. Following our previous approach on Xuan paper, four modern Bamboo papers manufactured using traditional or chemically-facilitated techniques were artificially aged by UVA radiation and changes to their optical properties were evaluated by reflectance and 3D-fluorescence spectroscopies. Paper samples produced by different methods displayed different fluorescence spectra and UVA photolysis of paper resulted in decreases in the fluorescence intensities and reflectance values, manifested as differing photoyellowing of the papers. Assays of reactive oxygen species, ROS, revealed that papers made by chemically-assisted pulping methods generally produce more hydrogen peroxide or superoxide radicals than those made by traditional methods, which correlates with their relative yellowing rates. Different spatial distributions of calcium and chlorine were also observed by SEM/EDS analysis in the chemically-manufactured papers, probably arising from the specific pulping and/or bleaching chemicals used in their manufacture.     

Estimating the real growth effects of blockbuster art exhibits: A time series approach

This paper addresses the evaluation of real growth forecasts made by impact studies. Intervention analysis is used to estimate the ex post impact of blockbuster exhibits on economic growth in Jackson, Mississippi (chosen because state and local governments provide regular subsidies to finance the exhibitions). Non-farm employment measures real economic growth and dummy variables capture the occurrence of the exhibitions. Univariate time series techniques identify and estimate a stationary process after filtering the data for seasonal and cyclical effects. The analysis estimates the short run impact on Jackson’s filtered employment series due to the blockbuster exhibitions as approximately 700 jobs.     

Effect of novel consolidants on mechanical and absorption properties of deteriorated wood by insect attack

The influence of chemical treatments based on novel organic products on the consolidation of deteriorated wood by insect attack was evaluated on two hardwoods and one softwood: fir (Abies alba), beech (Fagus sylvatica) and deciduous oak (Quercus sp.). Degraded and intact specimens of the three wood species were impregnated with two different chemical treatments aimed to verify the potential synergic action of the novel products on wood. Then, the specimens were subjected to bending, compression parallel to the grain, impact, hardness and water absorption tests. Untreated specimens of the same botanical species, both degraded and non-degraded, were examined for comparison purposes. The experimental results showed a different effectiveness of the proposed chemical treatments to improve the mechanical and absorption properties of degraded wood. The most effective treatment was the one assuming the concurrent use of the studied novel consolidants. The species more susceptible of the enhancement in mechanical properties were fir and beech. The observed differentiations were most likely caused by the different structure of the botanical species considered, leading to a consequent different product penetration in the wood structure. The dimensional stability in terms of water repellent and antiswelling efficiency, after a three-month immersion in deionized water, was found to improve in all the treated wood specimens. Overall, experimental results showed that the impact of the chemical treatments was higher on degraded samples than on intact ones.     

White America's Construction of Black Bodies: The Case of Ron Artest as a Model of Covert Racial Ideology in the NBA's Discourse

Abstract

Hybridization scholars have shown that the implosion of culture in response to globalization has led nations to feel threatened and thus reclaim their cultural differences. Nouvelle Star, the French version of American Idol, is a powerful representation of this process. The global format which emphasized popularity and emotions was rejected to showcase traits considered to be distinctly French: intellectualism and musical taste. By exploring the franchise's history and analyzing Nouvelle Star's episodes and audience responses, this paper describes how global similarities and national differences were produced in a movement of cultural hybridization.     

Identification of a fungal community on gilded wood carved heritage

During restoration activities, a fungal reddish area was noted on a gilded wood carved ceiling decoration from a sacristy of a church in Aveiro, Portugal. The protocols used to identify the fungal community present in this wooden material included the classical culturing methods and a molecular biology protocol based on the ability of denaturing high performance liquid chromatography (DHPLC) to separate fungal DNA from several species. This last method complemented the results obtained with the traditional culturing method approach and the overall study revealed three fungal species: Serpula lacrymans (Wulfen) P. Karsten, Paecilomyces lilacinus (Thom) Samson and Penicillium chrysogenum Thom. This is, to the author's knowledge, the first documented case of S. lacrymans in Portuguese built cultural heritage. Despite the antifungal solution applied and the dryer environment recommended, the water activity (Aw) levels recorded on location are still dangerously high and may allow fungal regrowth. Periodic inspections were advised.     

Enzymatic decolorization of bacterial pigments from culturally significant marble

Marble monuments and facades are susceptible to microbial colonization. Microbial growth on a marble surface can develop into unsightly red stains whose removal has proven problematic. The purpose of this study was to determine if the red-brown stains on Isamu Noguchi's marble sculpture Slide Mantra (1991) could be caused by pigment-producing microorganisms and to assess the potential of enzymatic stain remediation. Traditional cell culture methods were used to isolate a pigmented bacterium from a stained area of the sculpture. Sequencing and analysis of the 16S rRNA gene identified the organism as a strain of Serratia marcescens, and FT-IR spectroscopy demonstrated that the pigment produced by the bacteria was most likely a prodigiosin. Decolorization of the pigment in solution demonstrated that the enzyme laccase from the fungus Trametes versicolor has potential as a decolorizing agent. This study suggests that enzymatic decolorization may be applicable to stains on culturally significant marble caused by microbial colonization.     

The exhausted futures of neoliberalism: from promissory legitimacy to social anomy

ABSTRACT

The distinction between input-oriented legitimacy and output-oriented legitimacy (Scharpf, Fritz W, 1997. Economic Integration, Democracy and the Welfare State. Journal of European Public Policy, 4, 18–36) has been one of the most influential distinctions in political science. In this article I introduce a third arrangement supporting the legitimacy of political processes which I call promise-oriented legitimacy or, simply, promissory legitimacy. This term refers to the support political authority can gain from the credibility of promises political leaders make regarding future states of the world when justifying decisions and persuading others to follow them in their proposed course of action. Decisions gain support through claims about future development. Legitimacy crises arise if promises that were found credible become discredited and fail to motivate. I develop the concept of promissory legitimacy based on a discussion of what can be considered the most far-reaching political promissory regime of the last forty years: neoliberalism.     

A Bacillus subtilis cell fraction (BCF) inducing calcium carbonate precipitation: Biotechnological perspectives for monumental stone reinforcement

Monumental stone decay is a consequence of the weathering action of physical, chemical and biological factors, which induce a progressive increase in porosity. To cope this degradation, bacterial calcium carbonate mineralization has been proposed as a tool for the conservation of monumental calcareous stones. The advantage of this kind of treatment is to obtain a mineral product similar to the stone substrate, mimicking the natural process responsible for stone formation. In this work, the possibility to induce CaCO₃ mineralization by a bacteria-mediated system in absence of viable cells was investigated and tested on stone. Our results showed that Bacillus subtilis dead cells as wells as its bacterial cell wall fraction (BCF) can act as calcite crystallization nuclei in solution. BCF consolidating capability was further tested in laboratory on slab stones, and in situ on the Angera Church, a valuable 6th century monumental site. New crystals formation was observed inside pores and significant decrease in water absorption (up to 16.7%) in BCF treated samples. A little cohesion increase was observed in the treated area of the Angera Church, showing the potential of this application, even though further improvements are needed.