Papers by Hannelore Römich
Darstellung von 1,2,3,4-Tetramethyl-1,4-diboracyclohexen-2 und Umlagerung zum 1,2,3,4,5-Pentamethyl-2,3-dihydro-1,3-diborol / Synthesis of 1,2,3,4-Tetramethyl-1,4-diboracyclohexene-2 and Rearrangement to 1,2,3,4,5-Pentamethyl-2,3-dihydro-1,3-diborole Zeitschrift für Naturforschung B, 1988
Reaction between Cl2AlCH2CH2AlCl2 and BCl3 leads to Cl2BCH2CH2BCl2, in which halogen exchange is ... more Reaction between Cl2AlCH2CH2AlCl2 and BCl3 leads to Cl2BCH2CH2BCl2, in which halogen exchange is achieved by Bl3 to yield I2BCH2CH2BI2 (5). Redox reaction between butyne-2 and 5 results in the formation of 1,4-diiodo-2,3-dimethyl-1,4-diboracyclohexene-2 (1a) and iodine. Methylation of 1 a with AlMe3 leads to the title compound 1 d , established by 1H, 11B, 13C NMR. Heating of 1 d in toluene at 160 °C in a sealed tube results in an intramolecular isomerization to give 1,2,3,4,5-pentamethyl-2,3-dihydro-1,3-diborole (2d) in 90% yield.
Journal of Sol-Gel Science and Technology, 1997
The Radiometric Emanation Method (REM) was used for the characterization of barrier properties of... more The Radiometric Emanation Method (REM) was used for the characterization of barrier properties of protective coatings. Radon diffusion parameters of the hardened protective layers prepared from ORMOCER lacquers of varying compositions were examined. The differences in the barrier properties of non weathered and weathered ORMOCER coatings, as well as of INCRALAC coatings, were compared. REM is recommended for the characterization of barrier properties of protective coatings submitted to weathering at varying conditions and time.
Journal of Cultural Heritage, 2003
Country: France, 1999
... Author: Troll, Carola; Römich, Hannelore; Dickmann, Klaus; Hildenhagen, Jens Title Article/Ch... more ... Author: Troll, Carola; Römich, Hannelore; Dickmann, Klaus; Hildenhagen, Jens Title Article/Chapter: "Cleaning of corrosion crusts on stained glass windows with excimer lasers" Title of Source: Triennial meeting (12th), Lyon, 29 August - 3 September 1999: preprints. Vol. ...
Country: France, 1999
... Author: Troll, Carola; Römich, Hannelore; Dickmann, Klaus; Hildenhagen, Jens Title Article/Ch... more ... Author: Troll, Carola; Römich, Hannelore; Dickmann, Klaus; Hildenhagen, Jens Title Article/Chapter: "Cleaning of corrosion crusts on stained glass windows with excimer lasers" Title of Source: Triennial meeting (12th), Lyon, 29 August - 3 September 1999: preprints. Vol. ...
Butterworth-Heinemann eBooks, 1989
ICOMOS – Hefte des Deutschen Nationalkomitees, Aug 12, 2015
Engineering Geology, Feb 1, 2009
Microfocus X-ray computed tomography (µCT) is a useful tool for non-destructive analysis of corro... more Microfocus X-ray computed tomography (µCT) is a useful tool for non-destructive analysis of corroded archaeological glass objects and for monitoring restoration and conservation processes for these materials. This was demonstrated by µCT analysis of artificially corroded laboratory-produced glasses and corroded archaeological glasses retrieved from soil environments. Corrosion layers with a thickness of 20 µm or more can be detected as areas with lower X-ray attenuation values than the non-corroded glass. Features that are revealed by µCT analyses include the degree and patterns of corrosion and the presence of various internal structures in the corrosion layers. The study of restored corroded glasses demonstrates that mechanical and laser cleaning can be monitored efficiently. The study of consolidation practices, using test objects, requires the use of additives to increase X-ray attenuation values of the organic compounds that are used.
Springer proceedings in physics, 2005
Any cleaning process for stained glass windows has to consider the effectiveness of the treatment... more Any cleaning process for stained glass windows has to consider the effectiveness of the treatment but also the potential damage for the art object. A variety of mechanical and chemical methods is currently used in restoration practice. The most effective ones are criticized because of their long-term risks. Therefore, an interdisciplinary research project, carried out in Germany and funded by the “Deutsche Bundesstiftung Umwelt (DBU)” had explored the possibilities and limits of lasers for cleaning glass windows. At previous LACONA conferences the Excimer Laser equipment and results from the research project have been presented. This contribution puts the cleaning experiments in a broader context, by comparing lasers with conventional techniques. Scientific and practical aspects will be discussed, focussing on the removal of crust and aged polymers.
Journal of Cultural Heritage, Aug 1, 2000
The German Federal Foundation for the Environment (Deutsche Bundesstiftung Umwelt) is one of Euro... more The German Federal Foundation for the Environment (Deutsche Bundesstiftung Umwelt) is one of Europe's largest organizations of its kind. It supports innovative, exemplary projects for the protection of the environment and of national historic monuments and cultural landscapes. All projects are set up to provide a platform for researchers, craftsmen and restorers to find a common solution to difficult problems in conservation practice. More than 360 projects have been funded since 1990. Two recent projects deal with laser cleaning, one for stone and the other one for stained glass windows, the latter being presented here. This publication gives an overview on cleaning problems on stained glass windows and the project methodology. The interdisciplinary approach of the project provides the possibility of including experts in different fields to examine perspectives and limits of laser cleaning for stained glass windows. Two other publications in this issue (LACONA III) give selected results on cleaning experiments achieved within this project. © 2000 É ditions scientifiques et médicales Elsevier SAS
Journal of Cultural Heritage, 2003
Based on two independent feasibility studies in Germany (1992-1995), a research project "Laser cl... more Based on two independent feasibility studies in Germany (1992-1995), a research project "Laser cleaning of stained glass windows" was launched in 1997 with the aim to facilitate systematic investigations within an interdisciplinary cooperation. This paper will give an overview on the final results of the 3 years project. A prototype laser cleaning station was constructed, using an Excimer-laser operating at 248 nm. The impact of the laser radiation was examined on model substrates to define alteration thresholds and ablation thresholds for all relevant materials involved. A description of the resulting effects of the laser-substrate interactions will be given for glasses with different compositions and colours, for corrosion crusts and polymer coatings. As the ablation process is not self-limiting for these types of materials, different sensoring systems were evaluated. The results obtained from cleaning experiments on selected originals will be discussed to demonstrate the possibilities and limitations for the application of lasers in stained glass restoration.
Journal of Cultural Heritage, Nov 1, 2013
The methodology of protecting the European stained glass windows against environmental risk (e.g.... more The methodology of protecting the European stained glass windows against environmental risk (e.g. meteorological factors, air pollution, microorganisms) by means of an external glazing is not new. In spite of many scientific studies carried out in the last 20 years, some questions were still up for discussion. The European VIDRIO (2002-2005) project gave an answer to these questions. The research carried out by the different project partners established a new multidisciplinary approach aimed at evaluating the efficiency of the protective glazing systems and their effects on stained glass windows conservation, and finally at assessing the most appropriate strategy to preserve stained glass windows. Scientific results showed that the so-called isothermal glazing (i.e. ventilation by the air coming from the inside of the building) protected efficiently the ancient stained glass window from environmental attack (i.e. rain, pollutants, condensation, thermal shocks) with very limited secondary effects. The scientific research highlighted that its efficiency was strongly related to the technical design of the protective system. In particular, the ventilation and the size of the interspace had to be carefully considered. The research developed within the VIDRIO project was turned into general recommendations to the owners and practitioners on the best practice for the stained glass windows future conservation.
Journal of Cultural Heritage, Jul 1, 2009
... Original article. Consolidation of paint on stained glass windows: Comparative study and new ... more ... Original article. Consolidation of paint on stained glass windows: Comparative study and new approaches. Noemi Carmona a , b , Corresponding Author Contact Information , E-mail The Corresponding Author , Katrin Wittstadt a and Hannelore Römich a , c. ...
Mrs Bulletin, Jul 1, 2003
During several hundred years of burial in the soil, glass objects, especially those with the high... more During several hundred years of burial in the soil, glass objects, especially those with the high potassium content of medieval compositions, develop heavily corroded surfaces, showing phenomena such as local pitting, laminated layers, and browning effects. The long-term behavior of glass in the soil or in contact with groundwater is not only of interest to glass scientists with a background in archaeology, but also for those with a special interest in nuclear-waste management. Several attempts have been made to propose the decomposition of ancient glasses as an indicator for the performance of buried nuclear-waste glasses. In spite of differences in glass composition and exposure conditions, the development of alteration or corrosion layers with time is a common concern, as shown in this article. Laboratory experiments, representing a simplified model for real conditions, offer the possibility for systematic investigations.
This text originally appeared as chapter 5, 'Reinigung - Eine Gratwanderung' (pp. 101-28)... more This text originally appeared as chapter 5, 'Reinigung - Eine Gratwanderung' (pp. 101-28) in A. Wolff (ed.), Restaurierung und Konservierung historischer Glasmalereien, Mainz, 2000. Within the context of this research programme, scientists and conservators collaborated to assess various cleaning methods for historical stained glass. For cleaning glass surfaces there are the mechanical methods already being applied in most workshops, as well as the new chemical cleaning possibilities. Laboratory experiments were conducted initially on model glass in order to test the effectiveness and damage potential of these various methods; the model glass was examined both before and after cleaning by means of light microscopy and infra-red spectroscopy. In addition to this, cleaning tests were carried out on samples of original glass; electron-ray micro-analysis was also used to evaluate the results of these tests. The model-glass samples were corroded in advance by accelerated weathering in an attempt to simulate the damage seen on medieval glass. Enough model glass was prepared to allow any number of series of experiments to be carried out, in order to compare the effectiveness and suitability of the various chemical and mechanical methods and techniques. For the mechanical cleaning tests, a wide range of selected tools was tested by different conservators on pre-corroded model glass. This showed clearly that the success (or lack of it) of a cleaning episode was determined not just the choice of tool, but by the skill with which conservator wielded it. This observation was later confirmed by research on samples of original glass. Insensitive handling of tools or unsuitable tools could damage or completely destroy the gel layer. The gel layer should not be damaged, as this leads to increased levels of corrosion subsequently, though the encrustations should be reduced, as their hygroscopic qualities accelerate the corrosion processes. At the next stage, chemical cleaning methods were tested, and the results of cleaning with organic solvents (toluene, ethanol, acetone, etc.) and water-based solutions (oxalic acids, EDTA, ammoniac, etc.) compared with one another and evaluated. It became clear that strongly acidic and alkaline solutions, depending on the condition of the surface, could cause damage or have uncontrollable consequences. In the specific case of the glass from Erfurt Cathedral, for whose firmly fixed, very hard, opaque encrustations mechanical methods proved to be either ineffective or damaging to the glass, new chemical cleaning possibilities had to be found. Following comprehensive preliminary tests on model glass, various types of ion-exchanger and ammonium-carbonate solution were chosen. Both methods were successful in improving the transparency of some (but not all) of the samples. The experiments with the original material from Erfurt Cathedral clearly showed that successful cleaning was dependent on the particular composition of the encrustation. Really gentle cleaning can be achieved by chemical means, though only when the chemical agents are tailored to individual damage situations; this can only be achieved when scientific analysis is undertaken in tandem with the cleaning processes. The assessment of these mechanical and chemical cleaning methods was oriented towards treating corrosion on sensitive medieval glass. Nineteenth-century glass is generally less sensitive, though cleaning of this material must also be careful and very gentle. Scientific analysis alone is not enough to determine the choice of cleaning method, but can act as an aid to the conservator in selecting the right cleaning agent and method.
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Papers by Hannelore Römich