Analytische Chemie
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Organisationseinheit der BAM
- 4 Material und Umwelt (12)
- 4.5 Kunst- und Kulturgutanalyse (11)
- 8 Zerstörungsfreie Prüfung (11)
- 1 Analytische Chemie; Referenzmaterialien (8)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (5)
- 6 Materialchemie (4)
- 1.4 Prozessanalytik (3)
- 1.1 Anorganische Spurenanalytik (2)
- 6.6 Physik und chemische Analytik der Polymere (2)
- 7 Bauwerkssicherheit (2)
- 8.0 Abteilungsleitung und andere (2)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (2)
- 1.3 Instrumentelle Analytik (1)
- 1.7 Organische Spuren- und Lebensmittelanalytik (1)
- 1.8 Umweltanalytik (1)
- 4.3 Schadstofftransfer und Umwelttechnologien (1)
- 5 Werkstofftechnik (1)
- 5.0 Abteilungsleitung und andere (1)
- 6.1 Oberflächen- und Dünnschichtanalyse (1)
- 6.3 Strukturanalytik (1)
- 7.1 Baustoffe (1)
- 7.4 Baustofftechnologie (1)
- 8.5 Röntgenbildgebung (1)
- 8.6 Faseroptische Sensorik (1)
- S Qualitätsinfrastruktur (1)
- S.2 Digitalisierung der Qualitätsinfrastruktur (1)
The implementation of fluorescent methods is of outstanding importance in the field of optical chemical sensor Technology and biosciences. Their bioanalytical applications are manifold including fluorescence microscopy, fluorescence in situ hybridization, DNA sequencing, fluorescence-activated cell sorting, immunoassays, analysis of DNA and Protein microarrays, and quantitative PCR, just to name a few examples. Particularly, fluorescence microscopy is a valuable method in the versatile field of biomedical imaging methods which nowadays utilizes different fluorescence Parameters like emission wavelength/Color and lifetime for the discrimination between different targets. Sectional Images are available with confocal microscopes. Tissue, cells or single cellular compartments can be stained and visualized with fluorescent dyes and biomolecules can be selectively labeled with fluorescent dyes to Monitor biomolecular interactions inside cells or at Membrane bound receptors.
On the other hand , fluorophores can act as indicator (or "molecular probe") to visualize intrinsically colorless and non-fluorescent ionic and neutral analytes such as pH, Oxygen (pO2), metal ions, anions, hydrogen peroxide or bioactive small organic molecules such as Sugars or nucleotides. Thereby, their photoluminescent properties (fluorescence or phoporescence intensity, exitation and/or Emission wavelength, emission lifetime or anisotropy) respond to the presence of these species in their immediate Environment. In general, the use of luminescent probes has the advantage that they can be delivered directly into the sample, and detected in a contactless remote mode. By now, these probes are often encapsulated in different types of nanoparticles (NPs) made from (biodegradable) organic polymers, biopolymers or inorganic materials like silica or bound to their surface.
Inductively coupled plasma mass spectrometry (ICP-MS) is based on formation of positively charged atomic ions in a high-frequency inductively coupled Argon plasma at atmospheric pressure. The ions are extracted and transferred from the plasma source into a mass analyzer operated at high vacuum via an interface equipped with a sampling and a skimmer cone. The ions are separated in the mass analyzer according to their charge to mass ratio. The ions are converted at a conversion dynode and are detected by use of a secondary electron multiplier or a Faraday cup.
From an analytical point of view, ICP-MS is a well-established method for multi-elemental analysis in particular for elements at trace- and ultra-trace levels. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional analytical techniques, and relative limits of detection (LODs) in the low pg g−1 range and absolute LODs down to the attomol range. For these applications, ICP-MS excels by a high sensitivity which is independent of the molecular structure and a wide linear dynamic range. It has found acceptance in various application areas and during the last decade ICP-MS is also more and more applied for detection of rare earth elements particularly in the life sciences.
Due to the fact that all molecules introduced into the high temperature of the plasma in the ion source were completely dissociated and broken down into atoms, which are subsequently ionized, all elemental species information is completely lost. However, if the different species are separated before they enter the plasma by using adequate fractionation or separation techniques, then ICP-MS can be used as a very sensitive element-specific detector. We will discuss this feature of ICP-MS in this chapter in more detail at hand of the speciation of gadolinium-containing contrast agents.
Inductively coupled plasma mass spectrometry (ICP-MS) is a well-established analytical method for multi-elemental analysis in particular for elements at trace and ultra-trace levels. It has found acceptance in various application areas during the last decade. ICP-MS is also more and more applied for detection in the life sciences. For these applications, ICP-MS excels by a high sensitivity, which is independent of the molecular structure of the analyte, a wide linear dynamic range and by excellent multi-element capabilities. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional bioanalytical techniques, and relative limits of detection (LODs) in the low pg g−1 range and absolute LODs down to the attomol range.
In this chapter, we focus on new applications where the multi-element capability of ICP-MS is used for detection of lanthanoides or rare earth elements, which are applied as elemental stains or tags of biomolecules and in particular of antibodies.
Electromagnetic methods are widely used in Non-destructive Testing industries (NDT). In order to meet the requirements, safety-relevant products and structures have to be tested reliably during production or within subsequent maintenance cycles. For this purpose industrial users call for adapted testing methods which allow the detection of relevant defects such as cracks and pore in ferromagnetic or conductive materials. Automated testing systems and the application of sensor arrays are of great interest in order to enhance inspection quality and to decrease testing time and costs. Magneto resistance (MR) sensors like giant magneto resistance (GMR) or tunnel magneto resistance sensor (TMR) have proofed their suitability in many NDT-applications due to their extraordinary properties which combine high field sensitivity, a high spatial resolution and low costs. Due to their small size these sensors can be useful – in addition to the pure detection task – for a more detailed defect characterization and defect reconstruction providing defect size, orientation and geometry. This chapter gives a brief introduction of electromagnetic testing methods, i.e., magnetic particle inspection (MPI) and eddy current testing (ET), followed by two different approaches for which MR sensor arrays were successfully adapted.
Literature provides a wide range of hydrogen diffusion coefficients for low alloyed steels used in power plants. In fact, experimental boundary conditions and calculation methods have influence on the determination of these coefficients. The diffusion and trapping behavior in creep-resistant steel 7CrMoVTiB10-10 has been studied. Based on experimental carrier gas hot extraction (CGHE) data, a numerical model has been developed to describe the hydrogen transport and respective hydrogen distribution at elevated temperatures. The numerical results suggest that common calculation methods for diffusion coefficients are limited for experimental data analysis. The sample preparation time before CGHE experiment influences the determined diffusion coefficients with the consequence that non-homogeneous hydrogen concentration profiles have to be considered in the simulations.
Industrial Radiology is used for volumetric inspection of industrial objects. By penetration of these objects (typically weldments, pipes or castings) with X-ray or Gamma radiation the 3D-volume is projected onto a 2D image detector. The X-ray film is the oldest radiographic image detector and still in wide use in industry. The industrial X-ray film systems used today differ from these used in medicine. Medical film systems are described well in the literature, but industrial film systems not. So we start with a description of the properties and standards for industrial film systems. The requirements on image quality are defined by several standards and can be verified with different image quality indicators (IQIs). They describe the ability of the human being to detect small and low contrast indications in a noisy image background. The essential parameters for digital industrial radiology are described.
Since about 30 years electronic image detectors are gradually replacing the industrial film. These detectors are based on storage phosphor imaging plates in combination with Laser scanners (“Computed Radiography”, CR) or a variety of different digital detector arrays (DDA). Typical applications of CR and DDAs are discussed as well as new possibilities by digital image processing, which is enabled by the computer based image handling, processing and analysis.
Raw data from metabolomics experiments are initially subjected to peak identification and signal deconvolution to generate raw data matrices m × n, where m are samples and n are metabolites. We describe here simple statistical procedures on such multivariate data matrices, all provided as functions in the programming environment R, useful to normalize data, detect biomarkers, and perform sample classification.
A combination of different complementary methods is employed to investigate scaling of the molecular dynamics of two different liquid crystals. Each method is sensitive to different kind of fluctuations and provides therefore a different window to look at the molecular dynamics. In detail, broadband dielectric spectroscopy is combined with specific heat spectroscopy and neutron scattering. As systems the nematic liquid crystal E7 and a discotic liquid crystalline pyrene are considered. First of all it was proven that both systems show all peculiarities which are characteristic for glassy dynamics and the glassy state. Especially for the nematic liquid crystal E7 it could be unambiguously shown by a combination of dielectric and specific heat spectroscopy that the tumbling mode is the underlying motional process responsible for glassy dynamics. Dielectric investigations on the discotic liquid crystalline pyrene reveal that at the phase transition from the plastic crystalline to the hexagonal columnar liquid crystalline phase the molecular dynamics changes from a more strong to fragile temperature dependence of the relaxation rates. Moreover a combination of results obtained by specific heat spectroscopy with structural methods allows an estimation of the length scale relevant for the glass transition.
Heterogeneous catalysis is a key technology in modern industrial societies. The main steps of a catalytic process take place at the surfaces of complex materials. For the investigations of these surfaces X-ray photoelectron spectroscopy is widely used and fits ideally. At some suitable examples, it will be explained how XPS can help to understand such catalysts better. The focus is on selective oxidation catalysts, one of the main challenges of present research. Here it will illustrate, how changes in the near surface region influence the catalyst performance and, herewith the different stages (activation, maximum performance and deactivation) in the life of catalysts. Additionally, it will be stressed out how important information at different depth regions (surface, near-surface region, bulk) can be useful for comprehensive understanding of the material.
Another important subject is nanostructured catalysts with molecular sieves as supports or defined complexes as precursors. Finally, the combination of XPS with other methods used in the analysis of catalysts, e.g. electron microscopy, X-ray absorption spectroscopy and low energy ion scattering will be discussed.
This chapter gives an overview about polymer optical fiber (POF) sensors with the focus on structural and civil engineering applications. POF properties such as the high-strain range, the low Young’s modulus, and specific scattering effects open new fields for fiber-optic sensing applications. POF properties, sensitivities, and cross-sensitivities that are relevant for sensing are introduced. Advantages and limitations are discussed. State-of-the-art POF sensors and application examples are presented in subsections with regard to their underlying measurement principles.
In Goethes naturwissenschaftlichen Sammlungen, die als Arbeits- und Studiensammlungen, zum Teil aber auch als Lehrsammlung für den Sohn August angelegt sind, haben sich sowohl die eigentlichen Sammlungsobjekte als auch deren vermeintlich ursprünglichen Kontexte durch Beschriftungen, Etiketten und in Teilen noch existierende Präsentationsmedien erhalten. Es stellt sich jedoch die grundsätzliche Frage nach deren Ursprünglichkeit. Präsentieren sich die Objekte noch so wie zur Goethezeit oder erfuhren die historischen Dichotomien im Laufe der Zeit Veränderungen, sodass die zeitgenössischen Präsentationsformen und die damit verbundenen didaktischen Funktionen heute nicht mehr lesbar sind?
Messtechnik und Sensorik
(2018)
The book chapter first analyses the history of higher education in Europe. Second step describes the current Bologna process. Finally, the rule of the Bundesanstalt für Materialforschung und -Prüfung (BAM) in supporting PhD-students during their research and preparation of theire theses in cooperation with Universities is described
The paper presents rheometric results and hydration curves for cementitious systems based on cement mixed with different aqueous phases at solid volume fraction of = 0.45. The varied aqueous phases were deionized water, limewater, the filter residue of a cement paste mixed at w/c = 2.0, and the filtrate of cement paste at solid volume fraction of 0.45. Each cementitious system provided different amounts and sizes of particles formed in the aqueous phase. The pastes were observed with and without polycarboxylate ether based superplasticizer. It was observed that the presence of particles causes higher PCE saturation dosages to achieve a minimum value, but the minimum value is only affected in the case of large particles. In all cases with and without PCE, the presence of small particles causes increased plastic viscosity. In addition, with decreased number and size of hydrates in the aqueous phase the hydration was retarded, which was specifically pronounced in the presence of PCE
Das Kupferstichkabinett der Hamburger Kunsthalle besitzt seit seiner Gründung vier Zeichnungen von Leonardo da Vinci (1452–1519). Sie sind Teil eines umfangreichen Legats des Hamburger Kunsthändlers Georg Ernst Harzen, das der Stadt Hamburg für die 1869 eröffnete Kunsthalle als Besitz übereignet wurde. Die Zeichnungen gelten aufgrund ihrer Provenienzen und stilistischen Verankerung im Werk Leonardos als gesichert. Weiterführende materialtechnologische Untersuchungen wurden nun erstmals anlässlich der Ausstellung »Leonardo da Vinci – Die Zeichnungen im Hamburger Kupferstichkabinett« durchgeführt.
Schwarz auf Weiß
(2019)
In der Sammlung des Naturwissenschaftlichen Kabinetts Johann Wolfgang von Goethes wird ein eher unscheinbares Stück Papier aufbewahrt, welches einen grauschwarzen Aufstrich aufweist. Bei genauerer Betrachtung glaubt man, drei Querstreifen mit rötlicher, weißlicher und bläulicher Farbe innerhalb des grauschwarzen Aufstrichs zu erkennen. Das Papier weist oben die Skizze eines Prismas, im mittleren Bereich am rechten Rand die Beschriftungen „violett/blau“, „weiß“ sowie „gelb/roth“ auf. Interessanterweise ist die Aufschrift „violett/blau“ dem eher rötlichen, die Aufschrift „gelb/roth“ dem eher bläulichen Querstreifen zugeordnet. Die rechte untere Ecke ist mit „Sk“ (Seebeck?) gekennzeichnet. Sowohl die Beschriftungen als auch die Skizze wurden mit einem Graphitstift ausgeführt. Das Papier ist auf eine Pappe mit Papprahmen geklebt und mit schwarzem Papier umwickelt. Es ist unumstritten, dass es sich bei diesem Objekt um das Ergebnis eines naturwissenschaftlichen Experiments handelt, doch was stellt es dar und lässt sich die ursprüngliche Versuchsanordnung aus dem vorliegenden Befund und weiterer, heute zugänglicher naturwissenschaftlichen Untersuchungen rekonstruieren?
Although concrete itself is not a combustible material, concrete mixtures with high density, such has high-performance concretes (HPCs), are susceptible to significant damage during fires due to explosive spalling. Past research has shown that the inclusion of polymer fibres in high density concrete can significantly mitigate this fire damage. The exact mechanisms causing this increased spalling resistance are not yet fully under-stood, but it is thought that the fibres facilitate moisture transport during fire exposure, which in turn contributes to relief of internal stresses in the spalling-susceptible region. In this study, X-ray Computed Tomography (CT) was applied to observe the interaction between polymer fibres and cracking during thermal exposure. For this purpose, two concrete samples containing different polymer fibre types were subjected to incremental application of a defined thermal exposure. CT images were acquired before and after each thermal exposure and powerful image processing tools were used to segment the various material components. This enabled a detailed analysis of crack formation and propagation as well as the visualization and quantification of polymer fibre characteristics within the concrete. The results demonstrated that the orientation of both fibres and cracks in polymer-fibre reinforced concrete tend to be anisotropic. The results also indicated that crack geometry characteristics may be correlated with fibre orientation, with cracks tending to run parallel to fibre beds. Clear quantitative relationships were also observed between heating and increasing cracking levels, expressed in terms of both crack surface area and crack volume.
Das Ziel dieses Kapitels besteht darin, die Rolle von Konformitätsbewertung für die Erhöhung der Cybersicherheit von Produkten, Dienstleistungen und Prozessen zu betrachten. Dazu wird der Begriff Cybersicherheit beleuchtet sowie ausgewählte Cybersicherheitsnormen kurz vorgestellt. Im Folgenden wird der regulative europäische Rahmen für die Konformitätsbewertung aus ordnungspolitischer Sicht sowie der aktuelle Verordnungsentwurf zum Cybersecurity Act dargestellt und kritsch beleuchtet.
Unternehmen der chemischen Industrie müssen neuen Pfade beschreiten, um in einem veränderten Umfeld erfolgreich bestehen zu können. Dazu gehört insbesondere, das Potenzial digitaler Technologien zu nutzen. Die volle Integration und intelligente Vernetzung von Systemen und Prozessen kommt allerdings nur zögerlich voran. Dieser Beitrag ist ein Loblied auf die Feldebene. Er möchte dazu ermutigen, die Digitalisierung der Prozessindustrie auf Basis smarter Sensorik, Aktorik und Kommunikation ganzheitlicher zu denken und informiert über aktuelle technische Perspektiven, wie das Ein-Netzwerk-Paradigma, Ad-hoc-Vernetzungen, Edge-Computing, FPGAs, virtuelle Maschinen oder Blockchain. Diese geben smarter Sensorik, Aktorik und Kommunikation eine völlig neue Perspektive.
Eine Vielzahl unterschiedlicher Materialien findet für die farbliche Gestaltung von Zeichnungen Verwendung. Einige Pigmente und Farbstoffe, d.h. Tinten, Stifte oder Kreiden, waren nur für den Gebrauch als Zeichenmittel vorgesehen – andere wiederum finden sich auch in der Tafel- oder Fassmalerei. Ausgehend von schwarzen Zeichenmaterialien soll zunächst eine allgemeine Typologie der Farbmittel entwickelt werden, um den Kosmos dieser Vielfältigkeit zu illustrieren. In einem zweiten Teil werden farbige Elemente am Beispiel von Rötel in Zeichnungen hinterfragt, deren Funktion und Bedeutung sich aus der Betrachtung heraus nicht unbedingt sofort erschließt. So diente die Farbe hier weder der naturgetreuen Nachahmung, noch wurde sie für eine nachträgliche Wertsteigerung eingesetzt. Der dritte Teil dieses Exkurses widmet sich schließlich solchen „farbigen“ Elementen, deren Konnotationen sich aus den Zeichnungen nicht ermitteln lassen und die daher zunächst irritieren. Diese vermeintliche Farbigkeit war aber ursprünglich vielleicht gar nicht intendiert, sondern ist vielmehr auf Alterungs- und Korrosionsprozesse zurückzuführen.