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Unterschiedliche Werkstoffeigenschaften reagieren auf jeweils spezifische Weise auf Gittertyp, Gefüge und Defekte. Für die schadenstolerante Betrachtung von Werkstoff und Bauteil ist das Verständnis dieser Zusammenhänge essentiell. Der Beitrag gibt mit Hinblick auf additiv gefertigte metallische Bauteile mittels Selective Laser Melting einen kurzen, keineswegs vollständigen Überblick über Faktoren, die die Steifigkeit, Festigkeit, Duktilität, Zähigkeit, Ermüdungsrissausbreitung und Schwingfestigkeit beeinflussen. Es wird aufgezeigt, wie die bruchmechanische Betrachtung zur Quantifizierung der Zusammenhänge beitragen kann.
Im Beitrag wird über die mühevolle Sanierung von Objekten eines Kunstzweiges in Polen berichtet, der eine besondere diffizile Stellung in der langen Reihe von Werken der Kunst einnimmt. Es geht dabei um die bleiverglasten farbigen Fensterverschlüsse in Kirchen oder Profangebäuden. Das sind feingliedrige Gitterwerke aus zerbrechlichen und korrosionsanfälligen Materialien, die durch aggressive Umweltschadstoffe schweren Belastungen ausgesetzt sind. Wie bei keinem anderen Kunstzweig haben die einzelnen Bestandteile der Glasmalerei sowohl praktisch-technische als auch ästhetisch-künstlerische Aufgaben zu erfüllen. Bei der Restaurierung dieser Glasmalereifenster geht darum, neuentwickelte Methoden der Restaurierung oder Konservierung anzuwenden und letzte Erkenntnisse naturwissenschaftlicher Forschung zu nutzen. Diese Projekte sind ein Beispiel der interdisziplinären Zusammenarbeit zwischen Denkmalpflegern, Naturwissenschaftlern und Restauratoren aus Deutschland und Polen. An ausgewählten Restaurierungsobjekten wird von der fachgerechten, denkmalpflegerisch verantwortungsbewussten Arbeit berichtet.
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.
Welding is the most important joining technology. In the steel construction
industry, e.g. production of windmill sections, welding accounts for a
main part of the manufacturing costs and resource consumption. Moreover, social
issues attached to welding involve working in dangerous environments. This aspect
has unfortunately been neglected so far, in light of a predominant focus on economics
combined with a lack of suitable assessment methods. In this chapter,
exemplary welding processes are presented that reduce the environmental and
social impacts of thick metal plate welding. Social and environmental Life Cycle
Assessments for a thick metal plate joint are conducted for the purpose of
expressing and analysing the social and environmental impacts of welding.
Furthermore, it is shown that state-of-the-art technologies like Gas Metal Arc
Welding with modified spray arcs and Laser Arc-Hybrid Welding serve to increase
social and environmental performance in contrast to common technologies, and
therefore offer great potential for sustainable manufacturing.
A great deal is possible, even on the seabed. Together, wind and waves shake the foundations of the offshore wind turbines. "ere is also the “normal” current and ebb and #ow of the tides that are so distinctive in the North Sea. Pore water pressure can also occur on the seabed, loosening it. Where monopiles are involved, the worst case is that the stability of the whole turbine can be altered – even if such a monopile rammed into the seabed has a diameter of up to eight metres. Over half the planned offshore wind turbines in the North and Baltic Seas are to have monopile foundations, and over 40 % are to have multi-pile foundations, designed for example as a tripod. "is is why pile foundations and their loads deserve special attention. For one thing above all is to be avoided in plant operations, and that is the risk of turbine tilt.
Given their unique properties, ultrashort laser pulses with durations in the femtosecond to picosecond range currently open new avenues in the field of laser materials processing, resulting in groundbreaking new applications based on laser-induced surface functionalization. This article reviews the usability of temporally distributed energy deposition via double-pulse irradiation in applications based on laser ablation. This includes simple new techniques for surface nanostructuring and improved sensitivities in spectroscopic material analyses.
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.
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.