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- Fluorescence (2)
- ICP-MS (2)
- Offshore wind turbines (2)
- Silica (2)
- Adhesion (1)
- Ageing (1)
- Analysis of lanthanoides (1)
- Application (1)
- Arc welding (1)
- Archaeometry (1)
Various methods have been used for introducing fire retardant additives into polymers. Deposition of thick fire retardant coatings directly onto polymer substrates is an alternative technique. An important advantage of the coating technique is the preservation of the physical and chemical integrity of the polymer material. Moreover, the fire retardancy of the polymer materials can be achieved following their production. Suitable coating materials are inorganics, intumescent, char-forming, oxygendiluting, and cooling or radical quenching layers. The most important problem is to achieve sufficient coating thickness to withstand the direct attack of flame and to protect the polymer bulk from pyrolysis, otherwise blistering of coating, caused by emitted pyrolysis gases, is often observed. To avoid blistering of coating, the adhesion between polyolefin substrate and fire retardant coating has to be extraordinarily high.
In order to achieve such a high level of adhesion, the polymer surface has to be modified with adhesion-promoting functional groups. The deposition of thin plasma polymers as adhesion-promoting layers with NH2, OH or COOH groups has been the most suited method. These functional groups are able to form covalent bonds and other interactions between the fire-resistant coating and the plasma-modified polyolefin substrate. Additionally, the plasma polymer counteracts the strong mechanical stresses in the laminate on exposure to high temperatures by its flexibility.
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.
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.
This paper describes the experimental calibration of an existing Wiegmann–Polonceau roof truss based on modal parameters. Dynamic tests allowed the determination of the natural frequencies and mode shapes of the global truss and of individual truss members. The global and local modal configurations as well as coupled vibration of truss members are discussed. In addition, as truss members are axially loaded, the effect of stress stiffening on the modal parameters is considered. Moreover, several finite element models with different modelling assumptions for the details of the connections and member geometrical characteristics such as gusset plates and turnbuckles were developed. A suitable numerical model was chosen to represent the truss structural behavior. This paper focuses on the local measurement and analysis strategies applied to single truss members. The possibility of using a local analysis method, namely methods that consider individual members as part of a structure, is demonstrated to assess the behavior of the global truss structure. The comparison of the results after calibration reveals a very good correlation between the experimentally identified and numerically estimated modal parameters of the historic truss.
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.
High-speed photography was applied to investigate the explosive behavior of bubble-containing systems of the type organic solvent---gaseous oxidizing agent. Knowledge about the explosive behavior of such systems is of great importance, for example, for the safe operation of chemical reactors in oxidation processes in the liquid phase. Examples of the complex dynamical reaction of bubbles are elucidated where bubble-containing liquids were subjected to the impact of shockwaves. The different stages of the shock-induced explosive behavior of oxygen and oxygen plus inert gas bubbles were studied experimentally and theoretically mainly in liquid cyclohexane. Other solvents, such as cumene and 2-ethylhexanal, have been found to show that shock-induced bubble explosions can occur even if the gas phase of the bubble is not in the explosive range before impact. Tue influence of different parameters on the bubble Explosion process, such as the composition of the bubbles and the initial pressure, was investigated.
Limiting conditions for bubble explosions were determined. In addition to the behavior of individual bubbles, the interaction of exploding bubbles with one another was observed, which provides information on the Propagation mechanism of self-sustaining bubble-detonation waves. The results are important for the safety assessment of the explosion risks in corresponding two-phase systems.
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.
Due to their simple and reliable application, elastomers are used for many tasks. Many fields of application like transport, aviation and process technology, entail low temperatures where proper functionality of the employed seals has to be ensured. Therefore, understanding the low temperature behavior of elastomeric seals is important for safe seal operation to restrict the temperature application range.
For all areas of application, the question of seal lifetime is also important for replacement or maintenance intervals. The lifetime is especially important in applications that allow no seal replacement. Since the seal can determine the lifetime of storage in such cases, reliable lifetime estimation is necessary for these applications, and requires an extensive knowledge of the specific aging behavior.
Sol-Gel wood preservation
(2017)
The sol–gel-based modification of wood introduces chemical substances into wood in order to improve its characteristics and impart new properties. It stabilizes dimensions of wood (timber) components, increases its strength and resistance to water, and reduces cracking. Many sol–gel-based impregnations aim to protect against wood rot and fire. In most cases, the treatments are performed with alkoxysilanes, polysiloxanes, colloidal silica, or organically modified silica. In addition further substances such as titania, copper, and boron compounds have been applied on different types of wood. The precursor solutions were introduced by immersion, painting, or spray coating of wood followed by a drying and heat treatment process. The structure of the impregnated wood was investigated by SEM, EDX, TEM, FT-IR, NMR, and XRD. Frequently, test procedures according to standards were applied in order to assess the improvement in properties. Investigations demonstrate that silica and titania impregnations change properties first of all with increasing the amount of absorbed inorganic material (WPG), which is determined by the concentration of precursors, amount and size of particles in the sol, and the impregnation method. Sol–gel impregnation can be considered as an environmentally friendly approach of wood preservation. Various improvements in wood properties can be achieved such as reduced water uptake and volume swelling, improved weather stability, resistance against biodegradation, and fire retardancy.
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.