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Typology of Inks
Archives and museums around the world contain a vast number of manuscripts that were written in different inks: carbon inks, plant inks, iron-gall inks and mixed inks. Yet most archaeometric studies of manuscripts focus on the palette of pigments found in illuminated manuscripts whereas identification of the inks is still largely based on cultural-historical studies and visual inspections. One of the reasons of this disproportion in the studies can be explained by the properties of Raman spectroscopy, the technique of choice for identification of pigments. In contrast, this technique is only partially viable when dealing with organic colourants. Brown and Clark discuss these difficulties and the uncertainties of identification of iron-gall inks by Raman spectroscopy in their pioneering work on early medieval Anglo-Saxon manuscripts (K. Brown and R. Clark 2004). To facilitate instrumental analysis of inks, we have developed a protocol that starts with the identification of the inks type (Rabin et al. 2012) which doesn’t require complicated instrumentation and can be carried out by paleographers and codicologists.
Three typological ink classes
The black writing materials used in manuscript production in Antiquity und Middle Ages can be sorted in three typologically different ink classes: soot, plant and iron-gall. Soot ink is a fine dispersion of carbon pigments in a water soluble binding agent; plant-based ink consists of a solution of the tannins extracted from gallnuts or tree bark; iron-gall ink, is produced by mixing a soluble compound of iron (II) with gallic or tannic acid extracted from gallnuts or tree bark. Therefore, iron-gall ink presents a boundary case between solution and dispersion ink, in which a water-soluble preliminary stage oxidizes and evolves into a black, insoluble precipitate similar to the carbon pigments when the writing is exposed to air (Krekel 1999). The additional category of mixed inks, i.e. inks produced by addition of various metals to the soot inks or intentional mixing of iron-gall and soot - based inks started attracting scholarly attention only recently because their significance was established only a short while ago (Brun et al. 2016, Colini 2018, Nehring et al. 2021). We suggest that plant and mixed inks build a bridge from the carbon ink of Antiquity to the properly formulated iron-gall ink that became a standard black ink from the late Middle Ages to the 19th century when it gave way to modern inks.
The international research project HYCREF, funded by the European Commission in the 5 th Framework programme, aimed to develop methods to prepare homogenous and stable water-, soiland waste reference materials contaminated with mineral oil hydrocarbons and to test certify the mineral oil content by gas chromatographic methods. As mineral oil products are important sources for environmental contaminations a high need exists for certified reference materials for their determination using the new gas chromatographic methods (soil: ISO/FDIS 16703, waste: ENpr 14039, water: ISO 9377-2). The experimental conditions and results for preparation and characterisation of a total of nine reference materials (3 water-, 3 soil- and 3 waste materials) are described and discussed. Target values for the reference materials were defined at the beginning of the project in order to have clear quality criteria, which could be compared with the achieved results at the end of the project. These target specifications were related to the maximum uncertainty from test certification exercises (< 5 % for soil/waste and < 10 % for water), the maximum inhomogeneity between bottles (< 3 %) and minimum requirements for stability (> 5 years for soil/waste and > 2 years for water). The feasibility studies showed that solid materials (soil, waste) could be prepared sufficiently homogenous and stable. The test certified values of the 6 solid materials comprise a wide range of mineral oil content from about 200-9000 mg/kg with expanded uncertainties between 5.7-13.1 % using a coverage factor k (k = 2). The development of new water reference materials –the so-called “spiking pills” for an offshore- and a land-based discharge water represents one of the most innovative aspects of the project. The spiking pill technology facilitates the application and storage and improves the material stability compared with aqueous materials. Additional to the preparation and test certification of the reference materials investigations on the analytical method for the determination of mineral oil hydrocarbons were performed. The results obtained in relation to the optimisation of analytical method (extraction procedure, sample pretreatment, clean-up and measurement) were provided to the respective working group of ISO/TC 190, ISO/TC 147 and CEN/TC 292 and were incorporated into the ongoing standardisation procedures. The new version of ISO/FDIS 16703 (July 2004) includes the improvements based on HYCREF results, for example the increase of the solvent/sample ratio, the removal of acetone from the organic extracts and the use of column technique instead of batch technique for clean-up.
Tensile testing according to EN 10002-1 is one of the basic mechanical tests to characterise the mechanical properties of metallic materials. This testing procedure has been regularly under development for many decades in order to modify and amend it and to bring it up to an up to date standard. Today tensile testing for quality control in metals manufacturing industry is routinely performed automatically with computer controlled testing machines. Due to economical needs of industry proposals were made by a European Standard Committee to amend the standard EN 10002-1. A European research project with the acronym TENSTAND was started to validate the proposed modifications of the tensile testing standard. The work package 4 of the project was to validate the machine control characteristics. A comparison test program was started with ten partners, 4 test piece geometries and 3 test parameters for 6 materials, partly with upper and lower yield strength and partly with 0.2 % proof strength to compare experimental results according to the proposal to modify the standard EN 10002-1. Initially testing in the strain control mode was introduced as well as switching of the control mode to crosshead control 1 and switching of the testing speed at appropriate points during the test. The comparison test was evaluated statistically and scientifically. The following conclusions were derived from the comparison test and summarised as recommendations to the standard committees. The scatter of the material properties were not significantly reduced by introducing the amended testing procedure. Few of the reasons for the continuously observed scattercan be identified as follows: The material properties are observed to be widely dependent on the testing speed. As a consequence the range for the allowed testing speed must be reduced. The closed loop control was not optimised sufficiently in some tests, the use of complicated testing machine software led to misinterpretation of software commands, individual testing equipment and implementation of the tensile testing procedure led also to scatter of the material properties which lay in a range of few percent. This is blurred by the inhomogeneity of the material.
In this research project, a new OECD Test Guideline (TG) for the determination of “Particle Size and Particle Size Distributions of Nanomaterials” was developed as the existing OECD TG 110 is considered to be outdated in terms of applicable size range (not covering sizes <200 nm) and methods. By its scope with an applicable size range from 1 to 1000 nm the new Test Guideline (TG PSD) covers the whole nanoscale. The TG PSD is applicable for particulate and fibrous nanomaterials. The prescribed, pairwise measurement of fibre diameter and length in the TG PSD allows for the first time to differen-tiate fibres with regard to their size-dependent hazard properties. Measurement instructions for each included method were validated within two separated interlaboratory comparisons, as a distinction between near spherical particles and fibres when applying the methods has to be made.
Besides information on content and structure of the TG PSD, this final report outlines essential steps, considerations and organisational aspects during the development of the TG. Insights into the selec-tion, preparation and prevalidation of test materials used in the interlaboratory comparison are given. Finally, main results of the interlaboratory comparisons and their impacts on the TG PSD are pre-sented.
The classification of solid oxidizers according to the regulations on the transport of dangerous goods (based on the UN Recommendations/Model Regulations and accepted by all international organisations for the transport of dangerous goods as ADR, IMO, IATA) and in future also according to the GHS (Globally Harmonized System of Classification and Labelling of Chemicals) is performed on the basis of the results of the UN test O.1 (UN test O.1 ―Test for oxidizing solids‖ described in chapter 34.4.1 in the Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, see [1]). This test was introduced into the UN Manual of Tests and Criteria in 1995 as a replacement for a similar test from 1986. Even if the UN O.1 test as described in the current 5th revised edition of UN Manual of Tests and Criteria gives some improvements compared to the old test, which had had many deficiencies, there are still some problems left with this test in terms of e.g. repeatability or reproducibility of test results, how to handle compacted or multilayer formulations like tablets, toxicity and partly significantly varying particle size distribution within defined fractions of 150 μm to 300 μm of the reference oxidizer potassium bromate (KBrO3). For this reason the IGUS EOS working group installed an ad-hoc working group in 2002 assigned with the task to propose solutions for the existing problems. The appropriateness of such proposed solutions has to be proved by the method of interlaboratory (round robin) tests before they are presented for the adoption to the UN Committee of Experts on the TDG and on the GHS with a proposal of a completely revised test procedure.
The test methods UN Test L.2 / EN ISO 9038:2013 DIN EN 15188:2007 are applied to characterize the sustained combustibility of liquids i.e. the behaviour of a material under specified test conditions, whereby its vapour can be ignited by an ignition source and sufficient flammable vapour is produced to continue burning for at least 15 s after the source of ignition has been removed.
The aims of this interlaboratory test (IT) are the verification and/or the improvement (if necessary) of the verification data (reference material) in Annex B of EN ISO 9038:2013, the assessment of influencing (disturbing) factors (laboratory specific factors, which possibly may have an influence on the test result) and the assessment of the performance of the participating laboratories.
It could be demonstrated that the reference materials n-Dodecane, n-Decane and n-Undecane as mentioned in the standard are suitable and the verification shall continue to be valid.
Sustained combustibility tests are influenced by several factors like the presence of a draught shield, the experience of the laboratory assistant, verification of the apparatus, calibration of the metering device.
Based on the interlaboratory test, the gained experience and the actual results, well-founded measures / actions can be recommended to improve execution of the method.
The IT was organized by PTB, BAM and QuoData GmbH in the framework of the co-operation project CEQAT-DGHS Centre for Quality Assurance for Testing of Dangerous Goods and Hazardous Substances.
For the classification, safe handling and use of the chemicals, special standardized testing procedures have been developed and are used worldwide. Safety experts must be able to fully rely on the precise execution of the respective laboratory tests and assessments. In this context, interlaboratory tests are a crucial element of a laboratory's quality system. Participation in interlaboratory tests is explicitly recommended by the standard ISO/IEC 17025.
The present document reports the results of the interlaboratory test 2015-2016, which was performed on the test method DIN EN 15188:2007 “Determination of the spontaneous ignition behaviour of dust accumulations”. It was organized by BAM in the frame of the co-operation project CEQAT-DGHS Centre for Quality Assurance for Testing of Dangerous Goods and Hazardous Substances.
The test method DIN EN 15188:2007 is applied to characterize the self-ignition behaviour of combustible dusts. The experimental basis for describing the self-ignition behaviour of a given dust is the determination of the self-ignition temperatures (TSI) of differently-sized volumes of the dust sample by isoperibolic hot storage experiments (storage at constant oven temperatures) in commercially available ovens. The results measured this way reflect the dependence of the self-ignition temperatures on the volume of a dust accumulation.
The interlaboratory test 2015-2016 on the method DIN EN 15188:2007 is the latest in a systematic stepwise built up series of method validation interlaboratory tests and internal laboratory investigations. The aim of this interlaboratory test was to determine measurement uncertainties of the modified method DIN EN 15188 for different substances, covering a sufficiently wide range of self-ignition behaviours in the scope of the DIN EN 15188 of the four basket test to extrapolate to storage volumes up to 1000 m³ and the single basket test for a basket volume of 1000 cm³.
The precision of the four basket test and the single basket of the modified method DIN EN 15188 can be assessed as acceptable for the four sample materials investigated in the current interlaboratory test 2015-2016. It was possible to derive a functional equation for the measurement uncertainty U depending on the storage volume V. The measurement uncertainty cannot be ignored and must be considered, if TSI results should be used in practice.
For the classification of chemicals, special standardized test procedures have been developed and are used world-wide. Safe handling and use of these chemicals depend on the correct classification which therefore must be based on the precise and correct execution of the tests and their evaluation. In this context interlaboratory tests (round robin tests, interlaboratory comparisons / intercomparisons) are a crucial element of a laboratory's quality system. Participation in interlaboratory tests is explicitly recommended by the standard ISO/IEC 17025.
The present document reports on the results of the interlaboratory test 2009/2010 on the test methods UN O.2 “Test for oxidizing liquids” [1] / EC A.21 “Oxidizing Properties (Liquids)” [2] which was organized by the Center for Quality Assurance for Testing of Dangerous Goods and Hazardous Substances.
The test methods UN O.2 and EC A.21 are applied to characterize the oxidizing properties of liquid chemical substances or mixtures. To differentiate between chemicals with hazardous / dangerous oxidizing properties and chemicals which are not classified as hazardous / dangerous, the substance’s oxidizing properties are compared to those of a standard reference substance.
Since the methods (UN O.2 / EC A.21) were developed and came into force in the early nineties a systematic review concerning the practical application of the test method has not been carried out.
The classification of solid oxidizers according to the GHS (Globally Harmonized System of Classifica-tion and Labelling of Chemicals) and according to regulations on the transport of dangerous goods (based on the UN Recommendations/Model Regulations and implemented in all carrier domains as transport by road, railway, sea, air) is performed on the basis of the results of the UN test O.1 (―Test for oxidizing solids‖ described in chapter 34.4.1 in the Recommendations on the Transport of Danger-ous Goods, Manual of Tests and Criteria, Fifth revised edition, United Nations, New York and Geneva, 2009). This test was introduced into the UN Test Manual in 1995 as a replacement for a similar test from 1986. Even though the O.1 test is much better than the previous one there are still many prob-lems with this test. For this reason the IGUS-EOS working group (international group of experts on the explosion risks of unstable substances – working group: energetic and oxidizing substances) installed an ad-hoc working group in 2002 assigned with the task of proposing solutions for the existing prob-lems. The adequacy of such proposals has to be proven preferably by interlaboratory comparison (interlaboratory test) before they are presented to the UN Sub Committee for adoption into the UN Test Manual. The present report is the evaluation of an interlaboratory test which was designed by the Ad-hoc working group in order to find out whether the current method of comparing combustion times of test mixtures with those of reference mixtures is suitable in principle and whether some approaches for improvement of the method can be identified.
This is the final report on the proficiency test (PT) „Measurement of the particle size distribution of ceramic powders by laser diffraction”. The PT was organized by the Federal Institute for Materials Research and Testing (BAM), division 5.5 “Advanced technical ceramics”. The measurements took place from 12/2021 to 03/2022. The aim of the interlaboratory comparison was the proficiency assessment of the participating laboratories.
Management and realization of PT were performed in accordance with DIN EN ISO/IEC 17043:2010.
The basis of the harmonized measuring procedure and the instructions for the interlaboratory comparison was the standard ISO 13320:2020.
The statistical analysis was performed in accordance with DIN ISO 13528:2020 by use of the software PROLab Plus (QuoData GmbH, Dresden, Germany).
A group of 44 laboratories from 17 countries participated in the PT. Laser diffraction analyzers produced by 7 different manufacturers were used. The three test materials were commercial products. Overall, the measured characteristic values of the particle distributions (d10, d50 and d90) were in the size range between 0.5 and 25 μm. The final report contains all individual results in an anonymous way.