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Papers by Giovanna Di Pietro

Research paper thumbnail of The limited impact of acetic acid in archives and libraries

Heritage Science, 2018

For over two decades the exposure of paper heritage collections to outdoor and indoor generated g... more For over two decades the exposure of paper heritage collections to outdoor and indoor generated gaseous pollutants
has been perceived as an important threat to their preservation. Following explicit or implicit advise from conservation
science, many archives, libraries and museums have implemented special chemical filtration units to prevent possible
pollution induced damage. The most abundant, potentially harmful, indoor generated pollutant found in paper
loaded storage rooms is acetic acid. Acids are known to promote the chemical degradation of cellulose, the major
constituent of paper. These combined facts make clear why acetic acid has received much attention by conservation
science as a prime suspect pollutant causing paper degradation. However, new experimental evidence contradicts
the claim that acetic acid in typical storage situations causes significant damage to paper heritage. In this study a
mathematical model is presented that expresses our understanding of the causal chain of processes connecting
acetic acid exposure to paper damage. The model simply combines existing partial models describing (1) the transfer
of acetic acid through air, (2) the pH response of paper and (3) the kinetics of acid-catalyzed hydrolytic depolymerization.
The model makes apparent that the impact of acetic acid on archival and library

Research paper thumbnail of Towards a description of the degradation of archaeological birchbark

ICOM-CC 18th Triennial Conference 2017 Copenhagen, 2017

Archaeological birch-bark artefacts from ice patches are rare and little knowledge about their co... more Archaeological birch-bark artefacts from ice
patches are rare and little knowledge about
their conservation exists. The degradation
mechanisms are unknown and it is uncertain
how they affect the mechanical properties and
the cell structure. Due to this lack of knowledge,
the treatments for archaeological birch-bark artefacts
usually mimic those for waterlogged wood,
which are tuned to the preservation condition
of the object. This is assessed by measuring the
maximum water content and, in some cases, the
basic density and by microscopic examination of
microscopic examination. In this paper, it is explored
whether these parameters and techniques
can be used to characterise the degradation of
archaeological birch bark. Light microscopy examinations
showed that cell wall deformations
and fractures were present in both unaged reference
material and archaeological birch bark and
are not a distinct attribute of degradation. Cell
collapse was not detected in ice-logged samples,
while loss of birefringence is a potential tool to
characterise degradation. Birch bark cells cannot
be saturated with water, not even in the case
of waterlogged archaeological samples. The authors
conclude that maximum water content is
not a diagnostic tool to quantify degradation.

Research paper thumbnail of Chemical air filtration in archives and libraries reconsidered

Studies in Conservation, 2015

Research paper thumbnail of Ligterink 2007

Research paper thumbnail of Prediction of the relative humidity response of backboard-protected canvas paintings

Studies in Conservation, 1999

A simple mathematical model is presented that predicts the decay time of the internal relative hu... more A simple mathematical model is presented that predicts the decay time of the internal relative humidity (RH) of backboard-protected canvas paintings when subjected to external RH fluctuations. The model takes into account the permeance of the canvas and the ...

Research paper thumbnail of Silver-Mirroring Edge Patterns: Diffusion-Reaction Models for the Formation of Silver Mirroring on Silver Gelatin Glass Plates

Journal of the American Institute for Conservation, 2002

ABSTRACT

Research paper thumbnail of Silver-Mirroring Edge Patterns: Diffusion-Reaction Models for the Formation of Silver Mirroring on Silver Gelatin Glassplates

Journal of the American Institute for Conservation

ABSTRACT

Research paper thumbnail of Chapter 4 Examples of Using Advanced Analytical Techniques to Investigate the Degradation of Photographic Materials

Physical Techniques in the Study of Art, Archaeology and Cultural Heritage, 2007

Research paper thumbnail of A local microscopic model for the formation of silver mirroring on black and white photographs

Research paper thumbnail of Silver mirroring on silver gelatin glass negatives

Page 1. SILVER MIRRORING ON SILVER GELATIN GLASS NEGATIVES INAUGURAL DISSERTATION zur Erlangung d... more Page 1. SILVER MIRRORING ON SILVER GELATIN GLASS NEGATIVES INAUGURAL DISSERTATION zur Erlangung des Würde eines Doktor der Philosophie vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel von Giovanna Di Pietro ...

Research paper thumbnail of Micromorphological and chemical elucidation of the degradation mechanisms of birch bark archaeological artefacts

Research paper thumbnail of Looking at your monument from your office desk: a system to monitor on-line salt decay on walls

Research paper thumbnail of The Use of Lasers on Art Objects: An Investigation of the State of the Art

Research paper thumbnail of Depletion interaction and phase separation in mixtures of colloidal particles and nonionic micelles

Reversible flocculation is observed in aqueous suspensions of polymer colloids when a sufficient ... more Reversible flocculation is observed in aqueous suspensions of polymer colloids when a sufficient amount of nonionic amphiphile is added. The separation process is driven by depletion forces originated by the presence of the nonionic micelles. The minimum amphiphile concentration needed to induce flocculation, Φ Smin, decreases upon increasing the size of the colloidal particles. We also find that Φ Smin decreases as the temperature of the suspension approaches the cloud point temperature of the water — amphiphile system.

Research paper thumbnail of Phase Separation and Gel-like Structures in Mixtures of Colloids and Surfactant

Europhysics Letters (EPL), 1994

A colloidal suspension becomes unstable when a sufficient amount of non-ionic surfactant is added... more A colloidal suspension becomes unstable when a sufficient amount of non-ionic surfactant is added, undergoing a segregation process ascribable to depletion forces induced by the surfactant micelles. The concentrated phase which separates out is, however, less compact than theoretically expected and shows stable gel-like features. This anomaly can be imputed to a dynamic freezing of the segregation process due to

Research paper thumbnail of The limited impact of acetic acid in archives and libraries

Heritage Science, 2018

For over two decades the exposure of paper heritage collections to outdoor and indoor generated g... more For over two decades the exposure of paper heritage collections to outdoor and indoor generated gaseous pollutants
has been perceived as an important threat to their preservation. Following explicit or implicit advise from conservation
science, many archives, libraries and museums have implemented special chemical filtration units to prevent possible
pollution induced damage. The most abundant, potentially harmful, indoor generated pollutant found in paper
loaded storage rooms is acetic acid. Acids are known to promote the chemical degradation of cellulose, the major
constituent of paper. These combined facts make clear why acetic acid has received much attention by conservation
science as a prime suspect pollutant causing paper degradation. However, new experimental evidence contradicts
the claim that acetic acid in typical storage situations causes significant damage to paper heritage. In this study a
mathematical model is presented that expresses our understanding of the causal chain of processes connecting
acetic acid exposure to paper damage. The model simply combines existing partial models describing (1) the transfer
of acetic acid through air, (2) the pH response of paper and (3) the kinetics of acid-catalyzed hydrolytic depolymerization.
The model makes apparent that the impact of acetic acid on archival and library

Research paper thumbnail of Towards a description of the degradation of archaeological birchbark

ICOM-CC 18th Triennial Conference 2017 Copenhagen, 2017

Archaeological birch-bark artefacts from ice patches are rare and little knowledge about their co... more Archaeological birch-bark artefacts from ice
patches are rare and little knowledge about
their conservation exists. The degradation
mechanisms are unknown and it is uncertain
how they affect the mechanical properties and
the cell structure. Due to this lack of knowledge,
the treatments for archaeological birch-bark artefacts
usually mimic those for waterlogged wood,
which are tuned to the preservation condition
of the object. This is assessed by measuring the
maximum water content and, in some cases, the
basic density and by microscopic examination of
microscopic examination. In this paper, it is explored
whether these parameters and techniques
can be used to characterise the degradation of
archaeological birch bark. Light microscopy examinations
showed that cell wall deformations
and fractures were present in both unaged reference
material and archaeological birch bark and
are not a distinct attribute of degradation. Cell
collapse was not detected in ice-logged samples,
while loss of birefringence is a potential tool to
characterise degradation. Birch bark cells cannot
be saturated with water, not even in the case
of waterlogged archaeological samples. The authors
conclude that maximum water content is
not a diagnostic tool to quantify degradation.

Research paper thumbnail of Chemical air filtration in archives and libraries reconsidered

Studies in Conservation, 2015

Research paper thumbnail of Ligterink 2007

Research paper thumbnail of Prediction of the relative humidity response of backboard-protected canvas paintings

Studies in Conservation, 1999

A simple mathematical model is presented that predicts the decay time of the internal relative hu... more A simple mathematical model is presented that predicts the decay time of the internal relative humidity (RH) of backboard-protected canvas paintings when subjected to external RH fluctuations. The model takes into account the permeance of the canvas and the ...

Research paper thumbnail of Silver-Mirroring Edge Patterns: Diffusion-Reaction Models for the Formation of Silver Mirroring on Silver Gelatin Glass Plates

Journal of the American Institute for Conservation, 2002

ABSTRACT

Research paper thumbnail of Silver-Mirroring Edge Patterns: Diffusion-Reaction Models for the Formation of Silver Mirroring on Silver Gelatin Glassplates

Journal of the American Institute for Conservation

ABSTRACT

Research paper thumbnail of Chapter 4 Examples of Using Advanced Analytical Techniques to Investigate the Degradation of Photographic Materials

Physical Techniques in the Study of Art, Archaeology and Cultural Heritage, 2007

Research paper thumbnail of A local microscopic model for the formation of silver mirroring on black and white photographs

Research paper thumbnail of Silver mirroring on silver gelatin glass negatives

Page 1. SILVER MIRRORING ON SILVER GELATIN GLASS NEGATIVES INAUGURAL DISSERTATION zur Erlangung d... more Page 1. SILVER MIRRORING ON SILVER GELATIN GLASS NEGATIVES INAUGURAL DISSERTATION zur Erlangung des Würde eines Doktor der Philosophie vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel von Giovanna Di Pietro ...

Research paper thumbnail of Micromorphological and chemical elucidation of the degradation mechanisms of birch bark archaeological artefacts

Research paper thumbnail of Looking at your monument from your office desk: a system to monitor on-line salt decay on walls

Research paper thumbnail of The Use of Lasers on Art Objects: An Investigation of the State of the Art

Research paper thumbnail of Depletion interaction and phase separation in mixtures of colloidal particles and nonionic micelles

Reversible flocculation is observed in aqueous suspensions of polymer colloids when a sufficient ... more Reversible flocculation is observed in aqueous suspensions of polymer colloids when a sufficient amount of nonionic amphiphile is added. The separation process is driven by depletion forces originated by the presence of the nonionic micelles. The minimum amphiphile concentration needed to induce flocculation, Φ Smin, decreases upon increasing the size of the colloidal particles. We also find that Φ Smin decreases as the temperature of the suspension approaches the cloud point temperature of the water — amphiphile system.

Research paper thumbnail of Phase Separation and Gel-like Structures in Mixtures of Colloids and Surfactant

Europhysics Letters (EPL), 1994

A colloidal suspension becomes unstable when a sufficient amount of non-ionic surfactant is added... more A colloidal suspension becomes unstable when a sufficient amount of non-ionic surfactant is added, undergoing a segregation process ascribable to depletion forces induced by the surfactant micelles. The concentrated phase which separates out is, however, less compact than theoretically expected and shows stable gel-like features. This anomaly can be imputed to a dynamic freezing of the segregation process due to