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Eingeladener Vortrag
- nein (73)
N4-acetyl-SMX is the most important cross-reacting compound for the SMX-ELISA with concentrations of 1064 - 2488 ng/L in influent wastewater and 40 - 160 ng/L in effluent wastewater. The ELISAgrams for estrone show less interfering signals than for SMX. ELISAgrams of SMX and estrone display in effluent wastewater more interfering signals than in influent wastewater.
Mg-Y,RE-Zn systems present second phases with high thermal stability, promoting the increase of strength and creep resistance at high temperatures.
Mg and its alloys have a potential application as biomaterials due to their biocompatibility and degradation behaviour. The dominant corrosion mechanism in those alloys is the microgalvanic corrosion through coupling of the more noble second phases with the Mg matrix, and therefore a low concentration of those was sought.
Test procedure to characterize the cracking susceptibility of RSW-steels has been developed
During externally loaded test procedure all investigated steels (HDT780CD+Z100, HDT780C+ZE75/75, HX340LAD+Z100, HCT690TD+Z100) showed a cracking behavior
With increased specimen load, the crack length grows for the micro-alloyed-steel and TRIP-steel
Complex phase steels behavior during test procedure:
Crack length growth with increasing force could not be determined
The cracking susceptibility of electro-galvanized steels is less than hot-dip galvanized steels (in this case)
30
Experimental study and numerical simulation of hot crack formation for novel laser weldability test
(2015)
Hot cracking susceptibility in laser beam welding was assessed for several stainless steels by means of the CTW test
The strain rate has a significant influence on the formation of the hot crack
It was possible to determine the critical strain and strain rate that led to shot crack formation
A material ranking of hot cracking resistance could be made.A three-dimensional FEM using the contact element technique to simulate hot cracking during LBW under external load conditions was developed.
Good agreement between the strain field measured using the DIC technique and the simulation results
Susceptibility to hot cracking can be predicted by using FEM with the correct mechanical and thermo-physical material properties
Laser-GMA-hybrid welding of longitudinally welded large-diameter pipes of grades API- X80/ X120
(2015)
Potentials of the hybrid laser arc welding processes were investigated regarding reliable production of longitudinal welds of high strength pipe steels X80 and X120
Hybrid laser arc welding of the root pass:
Significant reduction in the weld cross section – savings of filler material
Lower heat input into the base material - improvement of mechanical properties of the weld joint
The arc type does not have any influence on the character of dilution in the laser part of the hybrid weld
14 mm deep root face was considered as optimum. No penetration of the filler material could be detected beyond this depth limit
Metal powder filler wires, micro alloyed with Ni and partly with Cr and Mo, guaranteed sufficient Charpy impact toughness at low temperature for the both investigated materials:
Hybrid laser arc welding is a very efficient process for the root pass in multi-pass welding and opens a large technical and economic potential for the manufacture of large pipes
As subcritical crack growth (SCCG) can reduce tensile strength of glasses by many orders of magni-tude, the potential for improvement of fatigue behaviour is most intriguing in developing ultra-strong glasses. An essential bottleneck is the basic understanding of the numerous interplaying pressure-, temperature- and water-affected relaxation phenomena at the crack tip and related toughening strat-egies. Therefore, the present project aims to advance the basic understanding of structural relaxa-tion effects and local properties caused by increased water concentration and tensile stresses at the crack tip as they are a key for structural toughening designs to develop SCCG-free glasses and glass surfaces.
Our first studies give clear evidence that glass structure and dynamics is strongly modified upon hy-dration of glasses. These changes are highly related to the nature of network formers but are affect-ed as well by the counter ions (network modifier). Results of the 1st project part suggest that struc-tural relaxation below glass transition temperature, i.e. overlapping of short-range (beta) and long-range (alpha) interactions can contribute to SCCG in water-free environments and that structurally dissolved water in the glasses can have decisive impact on this effect.
In the 2nd project stage specific glasses compositions will be investigated to gain an improved un-derstanding on the relation of sub-Tg relaxation and inert SCCG as well as to shed light to the relat-ed effects of dissolved water and its speciation. These glasses cover a broader range of different glass topologies and binding partners, whereby the coupling of alpha and beta relaxations is varied systematically by alkali-, alkaline earth ions and water species concentrations. Preparation of hy-drous glasses (up to 8 wt% water) will be performed by high pressure syntheses. Structure will be resolved by NMR, Raman and IR spectroscopy while structural relaxation is accessed in the temper-ature and frequency domain using dynamic mechanical spectroscopy and ultrasonic damping. We will focus on measurements of inert SCCG (region III) conducting experiments in vacuum and dry gas atmospheres using indentation techniques and stressing of glass specimens in DCB geometry.
Experimental data on SCCG will be provided to SPP groups, which deals with fatigue in metallic glasses and vice versa we will test theoretical predictions of ab-initio simulations of partner within SPP 1594 in order to quantify the effect of water on the crack tip. In summa topological factors con-trolling the subcritical crack growth with respect to water will be identified from which structural toughening designs for highly fatigue resistant-glasses can be derived.
As subcritical crack growth (SCCG) can reduce tensile strength of glasses by many orders of magnitude, the potential for improvement of fatigue behaviour is most intriguing in developing ultra-strong glasses. An essential bottleneck is the basic understanding of the numerous interplaying pressure-, temperature- and water-affected relaxation phenomena at the crack tip and related toughening strategies. Therefore, the present project aims to advance the basic understanding of structural relaxation effects and local properties caused by increased water concentration and tensile stresses at the crack tip as they are a key for structural toughening designs to develop SCCG-free glasses and glass surfaces.
Our first studies give clear evidence that glass structure and dynamics is strongly modified upon hydration of glasses. These changes are highly related to the nature of network formers but are affected as well by the counter ions (network modifier). Results of the 1st project part suggest that structural relaxation below glass transition temperature, i.e. overlapping of short-range (beta) and long-range (alpha) interactions can contribute to SCCG in water-free environments and that structurally dissolved water in the glasses can have decisive impact on this effect.
In the 2nd project stage specific glasses compositions will be investigated to gain an improved understanding on the relation of sub-Tg relaxation and inert SCCG as well as to shed light to the related effects of dissolved water and its speciation. These glasses cover a broader range of different glass topologies and binding partners, whereby the coupling of alpha and beta relaxations is varied systematically by alkali-, alkaline earth ions and water species concentrations. Preparation of hydrous glasses (up to 8 wt% water) will be performed by high pressure syntheses. Structure will be resolved by NMR, Raman and IR spectroscopy while structural relaxation is accessed in the temperature and frequency domain using dynamic mechanical spectroscopy and ultrasonic damping. We will focus on measurements of inert SCCG (region III) conducting experiments in vacuum and dry gas atmospheres using indentation techniques and stressing of glass specimens in DCB geometry.
Experimental data on SCCG will be provided to SPP groups, which deals with fatigue in metallic glasses and vice versa we will test theoretical predictions of ab-initio simulations of partner within SPP 1594 in order to quantify the effect of water on the crack tip. In summa topological factors controlling the subcritical crack growth with respect to water will be identified from which structural toughening designs for highly fatigue resistant-glasses can be derived.
Optimizing the performance of phase gratings for better visibility in Talbot- Lau interferometry
(2015)
We investigated the efficiency of phase gratings, i.e., the visibility upon variation of different parameters. Rotating around an axis parallel to the grid lines of the phase grating changes the grating’s shape and thereby the initial distribution of phase shifts. This yields high visibilities for shorter propagation distances than derived from box shapes. Tilting the grating in the scattering plane allows continuous tuning of the grating’s height that corresponds to an ideal phase shift for a particular photon energy. This opens the way for tuning the design energy suitable for the material under investigation. Our study included simulations for monochromatic sources with the sampling procedure.
Phänominilogische Studien des Blähens von bioactiven Gläsern verschiedener Zusammensetzung und Unteruschung des Einflusses einer Kristallisation. Die ausgasenden Komponenten wurden mittels Vakuumheißextraktion(VHE) und Infrarotspektroskopie identifiziert sowie der Einfluss von Korngröße, Mahldauer und -atmosphäre auf das Blähen unterucht.
Nowadays, the use of bioactive glasses is established for bone regeneration; however glasses are used mostly as powders, granules or in a paste. Sintered scaffolds are not used clinically, because of the in inherent problem of crystallization during the sintering process, resulting in poor mechanical properties and reduced bioactivity. The aim of this study was therefore to design new bioactive glasses, which combine improved processing and sintering with bioactivity.
Compared with the well-known Bioglass® 45S5 (SiO2-P2O5-CaO-Na2O) the calcium/alkalioxide ratio was increased, sodiumoxide was partially replaced by potassiumoxide and up to 8 mol% calciumflorid were added, in order to stabilize the glass against crystallization.
The sintering behavior of the new glasses was characterized by heating microscopy and compared to Bioglass® 45S5. The results showed that the new glasses achieved a sintered density of 88-99 % in contrast to only 57-67% for Bioglass® 45S5. In addition FTIR and XRD analyses showed that Bioglass® 45S5 crystallized during sintering while for the new glasses no crystalline phases were detected. The thermal properties of all glasses were studied by DTA and DSC measures, and the influence of grain size and heating rate were characterized. These studies showed a shift of start and end temperature of sintering process as well as the final density. The structure of sintered specimens during and after sintering was examined using light and electron microscopy (REM).
Bioglass® 45S5 is mainly used clinically as powders, granules or pastes instead of sintered compacts. This is due to the inherent problem of crystallization during the sintering, which results in poor mechanical properties and reduced bioactivity. Recently, new bioactive glasses with improved crystallization stability have been developed as promising candidates for manufacturing of sintered powder compacts for bone regeneration, which combine improved sintering behavior with bioactivity. Compared with the well-known Bioglass® 45S5 (SiO2-P2O5-CaO-Na2O) the calcium/alkali oxide ratio was increased, sodium oxide was partially replaced by potassium oxide and up to 3 mol% calcium fluoride were added, in order to stabilize the glass against crystallization. The aim of this study was to investigate the sintering and crystallization behavior of these new bioactive glasses.
Sintering and crystallization were characterized by heating microscopy, XRD, FTIR, SEM, and DTA. The results show that a sintered density of 88-99 % is achieved in contrast to only 57-67% for Bioglass® 45S5. In addition, FTIR and XRD analyses show that Bioglass® 45S5 crystallized during sintering while for the new glasses no crystalline phases are detected. The thermal properties of all glasses were studied by DTA measurements, and the influence of grain size was characterized. These studies showed that full densification can be attained for particle size < 32 µm, whereas coarser particles progressively increase residual porosity. Observed foaming phenomena, are strongly retarded by crystallization of beta-HAp.
To better understand the mechanism of hydrogen assisted cracking (HAC), it is important to investigate the 3D structure of the cracks non-destructively. Since, cracks introduced by HAC are usually very small, conventional x-ray imaging methods often lack the required spatial resolution.
However, the detection of those cracks can be enhanced by taking advantage of refraction at interfaces within the sample.
To image this refractive deflection we employ analyser based imaging (ABI). In this work we aim at proving the enhanced crack detection of ABI by investigating an alluminum alloy weld.
Es wird der DIN-Arbeitsausschuss Ermüdungsprüfung und seine Aufgaben vorgestellt. Ferner wird über die Thematik der thermischen Drift von Extensometern und die daraus resultierenden Fehler berichtet. Darüber hinaus werden aktuelle Aspekte der dynamischen Temperaturmessung im thermo-mechanischen Ermüdungsversuch vorgestellt.
Investigations on the tensile testing procedure conducted within the European project TENSTAND
(2015)
The current presentation shows the intention of the former European TENSTAND project on computer controlled tensile testing of metals. The history of the tensile testing standards is explained. Some test results of the TENSTAND project are shown. The presentation is focused on criticism of Chinese delegates in ISO TC 164 SC1 WG4 who stated that the TENSTAND project which was finished about 10 years ago came to wrong conclusions and were misleading. This presentation points out misunderstandings of the Chinese delegation in the test program and the results of the TENSTAND project and the former development of the tensile testing standard ISO 6892-1. Some tests of the TENSTAND project were newly evaluated using the original test data. The evaluation showed again that the conclusions of the TENSTAND project are correct.
Mycotoxins are secondary metabolites of fungi which have diverse detrimental effects on humans, animals and crops. Traceable worldwide in foods and animal feeds, these contaminants cause manifold diseases and extensive economic losses. Therefore, European legislation set maximum levels of distinct mycotoxins to minimize the risks for the buying public. But standardized food analysis techniques fail to detect masked mycotoxins, whose research increasingly moves to the fore in recent years. They are formed from detoxification metabolism of plants as well as from fungi, which conjugate for example with glucosides or dihexosides. All masked mycotoxins have one thing in common: They are not detectable with standard methods, thereby contributing to the overall exposure and pose an additional health risk for the consumer.
The dissertation work will focus on the following potential new group of masked toxins. Food safety relevant mycotoxins like zearalenone and ochratoxin A possess one or more 1,3-dicarbonyl moieties. Latter are principally able to form thermodynamically stable chelate complexes with metal cations. First investigations at BAM showed interactions between zearalenone and copper ions and it is conceivable that they possibly build a complex. Our main focus is now to identify, characterize and quantify 1,3-dicarbonyl mycotoxin metal complexes as potential candidates within the group of conjugated mycotoxins.
We will simulate processes of biotransformation and identify distinct metabolites by electrochemistry coupled to liquid chromatography/mass spectrometry (EC-HPLC-MS). The obtained knowledge contributes to a better understanding of masked mycotoxins and an improved monitoring of foods and feeds, to ensure food safety.
Due to the large quantities of construction and demolition waste (CDW) in Europe, its reuse or recycling is of particular importance. Although several countries already recycle high amounts of CDW, the use as secondary raw materials is often limited by inferior building material properties. Specific characteristics, like high porosity and low density are caused by hardened cement paste in crushed concrete and the content of mortar and plaster in brick debris. Impurities like wood or gypsum and also harmful substances like organic pollutants may be a major problem for a reuse and should be minimized. Therefore unwanted materials and impairing substances have to be separated from the secondary building material stream. This can be done during the demolition process by using techniques for selective dismantling or during the subsequent treatment of the resulting rubble. Since almost all processing steps are associated with environmental impacts, the benefits of saving natural resources by applying secondary building materials should be weighed carefully. An environmental performance evaluation was undertaken to assess different techniques for reducing gypsum in recycled concrete aggregates, aiming at a minimization of elutable sulfates. These results were compared to the environmental impacts of the extraction of natural aggregates for concrete.
Transport packages for spent nuclear fuel have to be assessed with respect to specific transport conditions. The physical state of the spent fuel and the fuel rod cladding as well as the geometric configuration of the fuel assemblies are important inputs for the evaluation of the package safety. The objective of this paper is to discuss the methodologies accepted by BAM for the authority assessment of spent fuel behavior within the package design approval procedure.
The effect of porosity and microcracking on the mechanical properties (strength, fracture toughness,Young’s modulus, and fracture energy) and thermal expansion of diesel particulate filter (DPF) gradecordierite materials has been investigated. A method to deconvolute the effect of porosity and microc-racking on Young’s modulus is proposed. In addition, the microcrack density and the pore morphologyfactor are calculated by applying a micromechanical differential scheme. The values of the investigatedmechanical properties are shown to decrease with an increase in porosity, but the thermal expansionvalues are insensitive to porosity. The variation in mechanical properties as a function of porosity leadsto distinct porosity dependence of thermal shock resistance for crack initiation and crack propagationfor DPF grade synthetic cordierite.
Tetrafluorethen wird von der Polymerindustrie seit Jahrzenten als monomeres Ausgangsmaterial sowohl für die Herstellung von Polymeren (PTFE) als auch für Kopolymere (PCTFE) eingesetzt.
Aufgrund seiner Eigenschaft als chemisch instabiles Gas kann TFE auch ohne Luftsauerstoff oder einen anderen Oxydator explosionsartig zerfallen. Nach der Initiierung des Zerfalls kann dieser unter bestimmten Bedingungen aufgrund des exothermen Reaktionsverhaltens sich selbstständig in Apparaten und Rohrleitungen ausbreiten. Dies geht aufgrund der freigesetzten Reaktionsenthalpie mit einem schlagartigen Anstieg von Druck und Temperatur einher, was zu erheblichen Belastungen der Materialien bis hin zum Versagen und Bruch und möglichen Folgeschäden einschließlich Personenschäden führen kann und in der Vergangenheit bereits mehrfach geführt hat.
Besonders nach Wartungsarbeiten besteht die Gefahr, dass Teilabschnitte im Rohrleitungssystem mit TFE, Stickstoff oder Luft gefüllt sind mit Drücken in einem Bereich zwischen technischem Vakuum und atmosphärischem Druck wohingegen angrenzende Rohrabschnitte oder Behälter immer noch TFE bei Betriebsdrücken bis 32 bar enthalten können. Dabei sind die Abschnitte in der Praxis häufig durch Kugelhähne voneinander getrennt, die aufgrund ihrer Öffnungscharakteristik bereits bei geringen Betätigungswinkeln eine große Querschnittsfreigabe für die Strömung im Rohr ermöglichen. Dadurch können schlagartige Kompressionsvorgänge des Gases im Niederdruckbereich ermöglicht werden, die allein aufgrund der thermodynamischen Zustandsänderung zu einer erheblichen Temperaturerhöhung führen und im schlimmsten Fall zur Initiierung der Zerfallsreaktion führen können.
Es wird erstmalig ein Versuchsaufbau im Industriemaßstab, der einer explosionsartigen Zerfallsreaktion von TFE standhalten kann. Zahlreiche Sicherheitskonzepte einschließlich diverser Berstscheibenkonfigurationen als auch zeitgesteuerte Schnellschlussventile wurden eingehend untersucht und bewertet, um die optimale Versuchskonfiguration für bestmögliche Reproduzierbarkeit festzulegen. Es fand eine systematische Untersuchung der schlagartigen Kompression der Systeme Luft/Luft, TFE/Luft, TFE/TFE und TFE/N2 statt.
In der Hochdrucksektion wurden Drücke bis 30 bar realisiert und im Niederdrucksektor konnten Anfangsdrücke im Bereich weniger Millibar bis hin zu Atmosphärendruck eingestellt werden.
Als Hauptergebnis wurde ein „Hazard diagram“ erstellt, mit dessen Hilfe die Zündwahrscheinlichkeit in Abhängigkeit vom Hochdruck und Niederdruck abgeschätzt werden kann. Gefährliche Bedingungen in Rohrleitungen können dadurch auf einfachem Weg identifiziert werden.
Als Referenzsystem zur Beurteilung der maximal erreichbaren nicht reaktiven Kompressions-temperaturen wurde Luft/Luft verwendet. Die damit ermittelten Daten dienten zur Bewertung von zusätzlichen exothermen Effekten, wie sie etwa bei Vorreaktion des TFE im Falle einer Dimerisierung auftreten können.
Entgegen der ursprünglichen Annahme konnten die Systeme TFE/Stickstoff und TFE/TFE im verwendeten Aufbau nicht durch Kompressionsvorgänge gezündet werden.
Die BAM erforscht mit Partnern an der TUM und DTU Methoden und Modelle für ein optimiertes Tragwerksmanagement von Infrastrukturbauwerken. Im Rahmen des vom BMVI und der BASt aufgelegten Projektclusters „Intelligente Brücke“ wurde ein Software-Prototyps zur zuverlässigkeitsbasierten Bewertung eines konkreten Spannbetonüberbaus unter Berücksichtigung von Inspektionen und Überwachungssystemen entwickelt. Der entwickelte Software-Prototyp ermöglicht Benutzern ohne vertiefte Kenntnisse der Zuverlässigkeitstheorie eine Berechnung des Einflusses von Bauwerksinformationen auf den Systemschädigungszustand und die Tragsicherheit. Auf dieser Grundlage können effiziente Inspektions- und Überwachungsmaßnahmen identifiziert und das Erhaltungsmanagement optimiert werden.
Fraunhofer Life Science Day
(2015)
Their high affinity, selectivity and specificity make monoclonal antibodies (mAbs) very important tools in research, diagnostics and therapy. The production of mAbs is routinely performed by hybridoma technique. Hybridomas are generated by fusing antibody-producing B cells with indefinitely proliferating myeloma cells. Both, cell fusion and the indispensable identification and isolation of the desired antibody-producing hybridoma clone is still far from being trivial.
We describe a novel method that should help to optimize the cell fusion, and the screening for antibody-secreting hapten-specific hybridoma cells by using fluorescence activated cell sorting and single-cell fusion. Hybridoma cells specific for a hapten were incubated with a hapten-peroxidase conjugate (hapten-HRP), which was subsequently incubated with a fluorophore-labeled polyclonal anti-peroxidase antibody (anti-HRP-Alexa Fluor® 488). To characterize the expression of membrane-bound immunoglobulin G (IgG) a fluorophore-labeled anti-mouse IgG antibody (anti-IgG-Alexa Fluor® 647) was used. Successful staining was verified by confocal laser scanning microscopy (CLSM). We show that it is possible to specifically label hapten-specific hybridoma cells. It should also be possible to use this labelling approach for the isolation of hapten-specific B cells from the spleen and use these cells for single-cell fusion. Parallelized cell fusion chips were developed to increase fusion efficiencies.
We present a concept for assessing the system reliability of monitored jacket support struc-tures of offshore wind turbines subjected to fatigue. The concept assumes that a structural health monitoring system periodically records accelerations of the jacket structure caused by ambient excitations. The recorded data is processed by a stochastic subspace-based damage detection algorithm to provide information on the global damage state of the jacket structure. This information is generally uncertain. To determine the effect of such uncertain global monitoring information on the structural reliability, the deterioration state of the jacket structure is described by a probabilistic fatigue deterioration model of all structural elements, which considers stochastic dependence among element fatigue behavior. The system deterioration model is coupled with a probabilistic structural model to compute the system failure probability. Global damage detection information is included in the reliability assessment through Bayesian updating of the system failure probability.
Build-up strategies for generating components of cylindrical shape with laser metal deposition
(2015)
Laser Metal Deposition LMD) as additive manufacturing process offers the potential to produce near net shape components. This reduces the amount of material and post-processing. The components are composed of individual layers. Already mall irregularities within a layer can add up over multiple layers and lead to error propagation. This paper deals with the issue of build-up strategies to minimize irregularities and prevent error propagation. Different travel paths and the influence of a changing starting point regarding to error propagation are discussed. Different deposition rates between core and peripheral area are detected and successfully compensated by adjusting the build-up sequence. Stainless steel and titanium alloy Ti-6Al-4V are used in the experiments. The results are intended to illustrate the potential of an adjusted build-up strategy and provide basic information on the way to an automated deposition process. This paper is of interest for engineers in industry or science using LMD as additive manufacturing process.
Introduction to PowderCell
(2015)
The kinetic energy of keV electrons backscattered from a rutile (TiO2) surface depends measurably on the mass of the scattering atom. This makes it possible to determine separately the angular distribution of electrons backscattered elastically from either Ti or O. Diffraction effects of these backscattered electrons inside the rutile crystal lead to the formation of Kikuchi patterns. The element-resolved Kikuchi patterns of Ti and O differ characteristically, but each can be described fairly well in terms of the dynamical theory of diffraction. Qualitatively, much of the differences can be understood by considering the relative arrangement of the Ti and O atoms with respect to planes defined by the crystal lattice.
In this paper, we present a new dataset consisting of 19,407 X-ray images. The images are organized in a public database called GDXray that can be used free of charge, but for research and educational purposes only. The database includes five groups of X-ray images: castings, welds, baggage, natural objects and settings. Each group has several series, and each series several X-ray images. Most of the series are annotated or labeled. In such cases, the coordinates of the bounding boxes of the objects of interest or the labels of the images are available in standard text files. The size of GDXray is 3.5 GB and it can be downloaded from our website. We believe that GDXray represents a relevant contribution to the X-ray testing community. On the one hand, students, researchers and engineers can use these X-ray images to develop, test and evaluate image analysis and computer vision algorithms without purchasing expensive X-ray equipment. On the other hand, these images can be used as a benchmark in order to test and compare the performance of different approaches on the same data. Moreover, the database can be used in the training programs of human inspectors.
Sealing and strengthening of the subsoil by injection is a major issue in the field of geotechnical engineering. This involves also jet grouting, which allows creating columns of grouted soil by eroding and mixing the in-situ soil with a thin cement suspension. A general difficulty of this method is to predict the column diameter and its material strength. Here, we present two-dimensional finite-difference numerical simulation results of a promising non-destructive quality assurance testing tool to evaluate the diameter of jet grout columns. This approach incorporates crosshole and downhole seismic measurements. Preliminary tests showed that this tool is applicable under real site conditions.
For absorption processes with fluctuating feed gas compositions it is vital to continuously adjust
the operation point to achieve energy efficiency. In this contribution a Raman-based advanced
process control (APC) is introduced for the absorption of carbon dioxide (CO2) using an aqueous
solution of monoethanolamine (MEA). The APC is based on a Raman spectroscopic analysis of
the composition and CO2 load of the scrubbing liquid and a non-linear model predictive control
(NMPC) to adjust the scrubbing liquid cycle. In addition, an outer real-time optimization loop is
set in place to update the set points for the absorption process depending on the current feed gas composition minimizing the energy consumption of the process. Implementation and testing of the APC have been carried out in a mini-plant at TU Berlin. During a plant operation of more than 160 hours robustness and stability of the APC were shown.
In the near future, it will be important to adopt innovative approaches and technologies in order to further guarantee the reliability and availability of the highway network. New tools are therefore needed in order to obtain in-depth information about the condition of bridges and its development early enough before significant, precarious damage cases occur. In 2011, the research program “Intelligente Brücken (Smart Bridges)” was launched by the BASt together with the BMVI to evolve systems for information and holistic evaluation for Bridge structures as a supplement to the current inspection-based maintenance management. Several projects dealt with the topic in the last few years and provided guidelines and a solid basis to move towards a first implementation considering the input of all research projects carried out so far.
In this paper we present results of our recent efforts to understand the mechanical interface behaviour of single-walled carbon nanotubes (CNTs) embedded in metal matrices. We conducted experimental pull-out tests of CNTs embedded in Pd or Au and found Maximum forces in the range 10 - 102 nN. These values are in good agreement with forces obtained from molecular Dynamics simulations taking into account surface functional Groups (SFGs) covalently linked to the CNT material. The dominant failure mode in experiment is a CNT rupture, which can be explained with the presence of SFGs. To qualify the existence of SFGs on our used CNT material, we pursue investigations by means of fluorescence labeling of surface species in combination with Raman imaging. We also report of a tensile test system to perform pull-out tests inside a transmission electron microscope to obtain in situ images of CNT-metal interfaces under mechanical loads at the atomic scale.
The intention of this compilation of articles was to introduce brand-new developments in the field of chemical imaging which have not been discussed in previous review articles. These include the design of new sensor nanomaterials based on photon uponversion crystals which convert near-infrared excitation light into sensor signals in the visible wavelength range highlighted by Christ and Schäferling. Sun, Ungerböck and Mayr describe the state of the art in oxygen imaging in microreactors and microfluidic devices. Miniaturized sensors for the imaging of oxygen, pH and temperature in microchips, microfluidic platforms and microbioreactors are reviewed by Pfeiffer and Nagl. Furthermore, Dmitriev and Papkovsky present a critical assessment of the applicability of probes for intracellular oxygen sensing.
I hope these articles provide an interesting insight into advanced luminescent sensor materials and the applications of optical micro- and nanosensors in fluorescence imaging today and will be inspiring for the reader. Finally, I would like to thank all authors and referees for spending their time to enable this collection of articles.
Themenschwerpunkt des 11. Kolloquiums war „Vom Sensor zur Prozessintelligenz“. Diskutiert wurde damit über die neusten Fortschritte in der Messtechnik und deren Implementierung sowie über neue Aspekte der Modellierung und das Umsetzen, also das Leben des daraus generierten Wissens im Prozess.
Das 11. Kolloquium Prozessanalytik in Wien startete mit einem Konferenzvorkurs zum Thema Ressourcenanalytik. Bei der Erschließung, Förderung und Umsetzung von natürlichen Rohstoffen gewinnen analytische Online-Verfahren eine immer größere Bedeutung. Gleichzeitig liegen die Analyte jedoch in sehr heterogenen Matrizes vor, sodass die Ressourcenanalytik ein sehr herausforderndes, für Fachleute damit aber auch sehr spannendes Thema ist.
Für diesen interdisziplinären Brückenschlag fanden an den beiden Hauptveranstaltungstagen vier Sessions mit jeweils drei Fachvorträgen und anschließender Diskussion statt: Im ersten Vortragsblock Sensoren – „messen“ wurden beispielhaft neue Messtechniken sowie übergeordnet deren Einbindung in die digitale Welt über Zukunftstrends wie Industrie 4.0 oder die Technologieroadmap Prozess-Sensoren 4.0 beschrieben. Mit Automatisierung – „implementieren“ wurden in einer zweiten Session Herausforderungen aber auch konkrete Lösungswege bei der Implementierung von Messtechnik im industriellen Umfeld aufgezeigt. Die Vortragsreihe Modelle – „erkennen“ widmete sich am zweiten Veranstaltungstag der Fragestellung, wie Messergebnisse in Wissen transferiert werden können, wobei insbesondere entsprechende Erfahrungen aus der Bioprozesstechnik zugänglich gemacht wurden.
Ebenfalls am zweiten Tag war schließlich Life-Cycle-Management – „leben“ Titel der „österreichischen Session“ zum Schwerpunktthema des Kolloquiums. In den drei Vorträgen wurde gezeigt, wie einmal generiertes Prozesswissen durch gutes Wissensmanagement und dessen Werkzeuge nicht nur tradiert sondern auch transferiert werden kann.
Besondere Berücksichtigung fanden beim diesjährigen Kolloquium auch die fast 40 hochqualitativen Posterbeiträge. Neben den ausgedehnten Postersessions an beiden Veranstaltungstagen erhielten die Autoren in zwei Posterslams jeweils eineinhalb Minuten Zeit, ihre Arbeit vorzustellen und das Fachpublikum zu vertiefenden Gesprächen im Anschluss einzuladen. Damit rückten nicht nur diese wertvollen Beiträge noch mehr ins Zentrum der Aufmerksamkeit, auch das Auditorium hatte so Gelegenheit, die Posterausstellung noch gezielter wahrzunehmen.
Das interdisziplinäre Doktorandenseminar, das unter den Teilnehmerinnen und Teilnehmern mittlerweile als echter Geheimtipp gehandelt wird, startete dieses Mal gleich in medias res mit einem Design-Thinking-Workshop zum Thema "Prozessanalytik für Industrie 4.0". Das Thema ist derzeit in aller Munde, erfährt eine eigene Dynamik und es wird hierzulande kräftig an Roadmaps und White Papers gestrickt. So kam aus Fachkreisen der VDI/GMA und NAMUR der Vorschlag, die Generation der zukünftigen Kolleginnen und Kollegen zu dem Thema zu befragen, die die heute verbrochenen Konzepte zukünftig selber ausbaden müssen.
Die Vorträge der nächsten beiden Tage umfassten wieder ein sehr breites und interdisziplinäres Themen-, Methoden- und Anwendungsspektrum. Neben lumineszenten Temperatursensoren in Mikrochipreaktoren, Mikromischer NMR-Detektion und in Arbeitsschutzkleidung integrierte Chemosensorik folgten einige Vorträge zu Verbesserungen und neunen Konzepten von Biosensoren sowie für Immuno-Micorarray-Verfahren. Die ebenfalls diskutierten Identifizierungs- und Quantifizierungsverfahren reichten von der Kokskohle bis zur Arzneitablette. Desweiteren wurde der Bogen von lumineszenten Nanopartikeln zu Kalibrationsstandards für Trübungssonden gespannt. Neben den Erzeugen der Daten ist ein intelligentes Datenmanagement notwendig um die Informationen auch zu verarbeiten und entsprechend dem User zu präsentieren.
Die interdisziplinäre Ausrichtung und Vielfalt der verschiedenen Forschungsbereiche spiegelte sich auch in den Postersession wieder. Die Themen umfassten etwa Softsensoren für die Regelung von CHO-Zellkultivierungen, Prozessanalytik für die Reaktivabsorption von CO2 aus industriellen Gasströmen oder Alkoholmarker in menschlichem Haar, um nur einige zu nennen.
The NanoMag project brings together various leading experts in magnetic nanoparticle synthesis as well as nanoparticle analysis and characterization from research institutes, companies, universities and metrology institutes that will perform cutting-edge research and develop applications in the field of magnetic particles. This work is supported by the European Commission Framework Programme7 under the NanoMag project [grant agreement no 604448].
Nach mehr als 15-jähriger Anwendung und mit der zwischenzeitlichen Einführung europäisch harmonisierter Normen für Fugenmaterialien war eine Anpassung Qualitäts- und Gütesicherungsanforderungen für Fugenfüllungen im Bundesfernstraßenbereich erforderlich. Hierbei ging es insbesondere darum, Maßnahmen und Verfahren zu entwickeln, um das nationale Qualitäts- und Gütesicherungsniveau weiter zu entwickeln und weiterhin sicher stellen zu können. Nach den Untersuchungserfahrungen im Labor und im Feld ging darum, neuartige Material- und Stoffkombinationen qualitätssicher dem Bauprozess zur Verfügung stellen zu können. Erforderliche Anforderungskriterien und zulässige Toleranzen der Lieferqualität wurden neu gefasst. Es wurde ein Verfahren entwickelt, europäische Bauprodukte qualitätsgesichert in den Bauprozess im Bundesfernstraßenbericht zu überführen.
Unter Berücksichtigung praktischer und wissenschaftlich-technischer Erkenntnisse der letzten 15 Jahre - insbesondere auch auf der Basis verschiedener BAM-Forschungsergebnisse und Zulassungsverfahren - erfolgte eine Überarbeitung der Grundlagen, Bauprinzipien, Ausführungs- und Einbaukriterien sowie der Zulassungs- und Gütesicherungsmaßnahmen für insgesamt 4 Bauarten von Fugenfüllsystemen für hochbeanspruchte Verkehrsflächen. In diesem - für den Bundesfernstraßenbereich verbindlichen bautechnischen Regelwerk - finden insbesondere auch die Ergebnisse mehrerer wissenschaftlicher Vorhaben der BAM bezüglich labortechnischer Untersuchungen und Felduntersuchungen zum Funktionsverhalten und zur Dauerhaftigkeit erste baurechtliche Konsequenzen. Auf der Basis von Untersuchungen u.a. im Brückenbau wurden Regelungen für die Fugenausbildung in Asphalt und bei Befestigungskombinationen erarbeitet und umgesetzt. Damit konnten umfassende Regelungen für die maßgebenden Fahrbahnbeläge im Bundesfernstraßenbereich der Straßenbauverwaltung und ausführenden Industrieunternehmungen zur Verfügung gestellt werden. Die Neufassung dieser Regelungen dient darüber hinaus dem Ziel, den von der BAM vertretenen Wechsel hin zu einer performance-bezogenen Bewertungsmethodik, vorzubereiten.
Bei der Freisetzung von brennbaren und/oder toxischen Stoffen mit einem Siedepunkt nahe der Umgebungstemperatur (z.B. Fluorwasserstoff) oder von erhitzten Flüssigkeiten, findet die Verdunstung bei höheren Dampfdrücken statt. In diesem Bereich ist der Massenstrom beim Stoffübergang von der flüssigen in die gasförmige Phase mit herkömmlichen Modellen nur noch schwer zu beschreiben. Während der Annäherung an den Siedepunkt findet ein gleitender Übergang von der konzentrationsgradient-dominierten Verdunstung in die wärmestrom-dominierte Verdampfung statt. Die meisten Verdunstungsmodelle wurden entwickelt, um den Stoffübergang bei geringen Dampfdrücken zu beschreiben. Der Verdunstungsmassenstrom berechnet sich aus dem Stoffübergangskoeffizienten, der anhand der Grenzschichtparameter, wie die charakteristische Länge, Windgeschwindigkeit und die Stoffeigenschaften bestimmt wird, und einem Druckterm, der je nach Modell in linearer oder logarithmischer Formulierung vorliegt.
Während letztere am Siedepunkt zu einem unendlichen Massenstrom führt, liefert der lineare Ansatz (unterschiedliche) finite Werte. Obwohl unbestritten sein dürfte, dass die Annahme eines unendlichen Massenstromes nicht plausibel ist, stellt sich die Frage welcher Ansatz die Realität in der Nähe der Siedetemperatur am besten wiedergibt.
Da für den hier diskutierten Dampfdruckbereich keine veröffentlichten Daten zu finden waren, wurden in der BAM neue Messreihen durchgeführt. In einer beheizbaren Wanne mit 90 cm Durchmesser wurde in Freilandversuchen der Massenstrom für verschiedene Substanzen bei unterschiedlichsten Temperaturen und somit Dampfdrücken bestimmt. Zusammen mit den Ergebnissen früherer Experimente in der BAM zur Verdunstung unter Freilandbedingungen liegt jetzt eine ausreichende Datenbasis für die Bewertung der Modelle und insbesondere der Ansätze für den Druckterm vor.
The numerical simulations of high power laser keyhole welding at different welding positions are performed by using Volume-Of-Fluid (VOF) method. The main material is SS400. The multi-physics phenomenon is considered using several models, such as the heat flux of Gaussian heat source, the recoil pressure with Clausisus-Clapeyron equation, the Marangoni flow considering temperature gradient, the buoyancy force with Boussinesq approximation, the additional shear stress and heat source due to metallic vapor ejected through keyhole entrance, the bubble formation assumed as adiabatic bubble, and the multiple-reflection by solving proper discriminant, are used. To analyze the fluid flow pattern, the concept of streamline formed by reconstructing the value of the velocity vector is applied.
Partial and full penetration cases at different welding positions are considered. The welding position seems to have only a minor influence on bead formation characteristics in both cases. This is probably due to the fact that the recoil pressure has a major influence when compared to other driving forces. The flow characteristics and fluid velocity in weld pool are analyzed to compare the gravity direction effect at different welding positions. It is observed that the clockwise flow pattern is mainly formed by the recoil pressure on the keyhole surface in the case of partial penetration. The laser energy can't maintain the whole weld pool when the weld pool size becomes too large. And then the solidification starts from the middle part of weld pool and a necked weld pool shape is formed. In the full penetration welding, the weld pool flow patterns are affected by the leakage of laser power through the full penetration keyhole and also by surface tension. Furthermore, the numerical simulation of full penetration welding with AISI316L is also performed to analyze the effect of material properties. The weld bead shapes obtained by simulations were compared with the corresponding experimental results to confirm the validity of the process models adopted and the CFD simulation tool.