Fachbereich 4 - Institut Mess- und Senstortechnik
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The detection of soil erosion processes in dams, hydraulic heave failure or corrosion processes of reinforcing steel in concrete are a small selection of measuring applications in civil engineering where the impedance analysis can be used to determine the measurand. Those measuring applications are having high requirements for the measuring hardware. For example a common interface for fast data exchange, high resolution, independent functionality and easy customizability to suit the measuring application. For that reason, a well-known application for steel-mill process monitoring can be used as a development platform. This hardware platform is based on a vector network analyzer and is meeting the requirements mainly. However, a couple of modifications has to be made, like replacing the ADC for a higher sample rate, Ethernet for easy and fast data exchange and the microcontroller for more calculation power.
Process Monitoring in Steel-Mills using Impedance Analysis: VNA Improvement for Data Acquisition
(2017)
The process automation extends over every manufacturing step of a product in the steel-mill to increase the quality, quantity and energy efficiency. The product dimensions are an important part of the quality control; these must maintain the specified tolerances. Additional to the cross-sectional-area, the measured data contains much more information about the manufacturing process, e.g. eccentricity, condition of the rolls and defects of the rod. For analyzing the measured data and to gather more information about the manufacturing process it is necessary to increase the speed of the data acquisition by performing some modifications of the VNA, e.g. faster analog to digital converter and microcontroller, improved firmware and optimized values of the passive electrical components for faster time constants and transient responses.
Rolling mills are continually improved and opti-mized by implementing innovative technology to decrease costs and scrap. Despite of the progressive automation and experience, some important process parameters can still not be determined with sufficient accuracy. As part of the research project PIREF, the velocity of the hot rolled rod shall be measured by using im-pedance analysis to estimate the volumetric flow rate of the mate-rial. For a high accuracy measurement of the impedance, a pow-erful VNA is used. To minimize errors in the measurement, caused by e.g. temperature drift, a correction of the measurement fre-quency is needed. This must be achieved without recalibration of the VNA to avoid faulty behavior of the online control. To solve this problem, an approach based on a polynomial regression is presented in this work.
Quality and dimensional accuracy of hot rolled steel rods depend on several process parameters. In fact many of these crucial parameters are not be sufficiently determined yet. By improving automation and process control costs and scrap of production can be decreased. As part of the research project PIREF, one of these parameters – the roll gap – is under investigation beside other topics. Before starting rolling, the roll gap is typically set to a fixed value according to the planed dimensions of the product, but the forces during the rolling of the rod cause an enlargement of the roll gap. In which way the rolls change their position and form shall be examined in our research project. Therefore a first experimental setup has been built up to determine the change in position of the rolls under applied force. This is realized by a pot core coil as sensor using impedance analysis. The first results are presented in this work as a proof-of-principle.
Process diagnosis is an important method for improving product quality in rolling mills. In addition, the measurement of process variables such as roll gap, cross-sectional area, velocity, and volume flow of the material during production enables the implementation of model-based control concepts to improve product quality. The non-contact speed measurement of hot wire and bar is still a big challenge due to the rough environmental conditions and is solved mainly with optical measuring methods in production. The alternative measurement principle with eddy current sensors presented in this paper enables velocity measurement at locations in a rolling mill where optical measurement methods are not suitable.
In the field of producing hot-rolled steel bars and wires, hot rolling mills are incomplete or barely equipped with measuring technology for recording relevant process parameters. Therefore, there is a big potential to increase product quality and to decrease costs and scrap by improving process control establishing new sensor systems. One of these crucial parameters is the roll gap,which is investigated as part of the research project PIREF. In this paper an experimental setup for examining the roll gap during a rolling process is presented and based on these results different sensor arrangements are discussed.
Velocity Approximation of Hot Steel Rods Using Frequency Spectroscopy of the Cross-Section Area
(2019)
In this work, an approach for velocity approximation of hot steel rods based on frequency spectroscopy is presented. For this purpose, a sensor already implemented in a rolling mill for measuring the cross-sectional area of the rolling stock is used to obtain information about the velocity of the hot rods. Moreover, the effect of forward slip is briefly discussed.
The development of innovative measuring technology for process optimization in hot rolling mills becomes more and more relevant because of increasing demands on product quality. Measurement technology for high-resolution non-contact cross-sectional area measurement has shown that the variation in cross-sectional area contains information about the rolling process. This information can be used for the development of new measurement devices and analytical methods for process optimization. The harsh environmental conditions and strict safety regulations result in great effort when implementing a new sensor prototype in hot rolling mills. For this reason, this work presents a mechatronic test stand that can simulate the cross-sectional area variation under laboratory conditions realistically.
Mobile Walzenmesstechnik
(2003)
Magnetisch-induktive Techniken finden seit langer Zeit viele Anwendungsfelder in der Medizin, Sicherheitstechnik und der Industrie. Obwohl die technischen Grundlagen seit vielen Jahrzehnten bekannt sind, werden auf Basis detaillierter Analysen spezielle Lösungsansätze verfolgt, die neuartiges Anwendungspotential erschließen sollen. Dazu dienen verbesserte Werkzeuge wie Computersimulationen und analytische Berechnungen sowie neu kombinierte Methoden und Aufbauten aus Leistungselektronik und Signaldetektion. Die Vorteile magnetisch-induktiver Techniken sind dabei u.a., dass sie das Prüfobjekt nicht schädigen, berührungslos arbeiten, robust gegenüber Verschmutzungen und einfach im Aufbau sind. Ein Nachteil dieser Technik ist die unzureichende Auflösung von feinen Strukturen. In der aktuellen Forschung und Entwicklung werden unterschiedliche Spulenanordnungen zur Anwendung in industriellen und medizinischen Fragestellungen untersucht und optimiert. Thema dieser Arbeit ist es, durch Verbesserung der Spuleneigenschaften, neue Anwendungsbereiche für die zerstörungsfreie Materialprüfung zu erschließen. Es wird eine Methode vorgestellt, die Eigenschaften magnetisch-induktiver Tastspulen zu verbessern und so den Aufwand bei der Signalverarbeitung zur Rekonstruktion im Rechner zu reduzieren sowie die Auflösung zu erhöhen. Dazu werden zwei Spulenanordnungen, Transmissions -Tastspulen und Gradiometer - Tastspulen, vergleichend
gegenübergestellt und ihre technischen Grenzen aufgezeigt.
In the field of magnetic inductance tomography,
signal processing is a real challenge. This is due to the divergent
nature of magnetic fields. The sensitivity, i.e. the change in the
receiving signal by means of an electrically conductive sample
in a measuring volume depends strongly on the positioning
of the sample. Objects that are located near the transmitting
or receiving coils are very well locatable, where objects in
larger distance are hard to detect. In this paper an approach
is presented that improves the topology of the magnetic fields
in the ”magnetic induction tomography” (MIT) by changing
geometric constructions and current patterns of coils so far,
as to allow a sharper localization of objects within the space.
The aim is to level the distribution of the sensitivity in the
measuring volume, so that electrically conductive objects with
a larger distance between transmitting and receiving unit can
be detected with almost the same signal intensity as objects
close to the transmitting and receiving unit. The simulation tool
Comsolic is used for the geometric modeling making a finite
element analysis (FEA). The subsequent signal processing and
analysis of the simulation results are implemented in Matlabic .
Within this FEA the coil geometries and current patterns are
changed numerically, so that the minimum object size, that is
still detectable, is, compared to the known MIT, reduced and the
sensitivity of the system is improved. To validate the simulation in
Comsolic , first simulation results are compared with analytical
models and analyses.
Methods of red-hot rod shape testing require a robust non-contact measurement principle as a touch point could lead to damages to the rod and the detection unit. Therefore a new basic approach based on high frequency eddy current (HFEC) has been investigated. Due to the robustness and the ability to determine the rod shape even above the Curie temperature this principle is especially well suited and can be implemented in the production process directly. The first automatic measurement setup was successfully developed with promising results. Hereby a defect of ovality was detected with a parallel RLC-oscillator. The capacity of this RLC-oscillator is constant whereas the inductance is the measurement part that varies due to eddy current interactions with the rod.
Fat content of liver is an essential parameter to decide whether a liver is suitable for transplantation or not. The determination of fat content is often challenging and usually there is not enough time to bring a specimen to a pathologic laboratory. That is why transplantation clinics need a technique to measure the fat content of a graft. In this paper the theoretical basics and an existing laboratory setup are presented.
The harmonic and interharmonic analysis recommendations are contained in the latest International Electrotechnical Commission (IEC) standards on power quality. Measurement and analysis experiences have shown that great difficulties arise in the interharmonics detection and measurement with acceptable levels of accuracy. In this paper, the spectral leakage problems of the discrete Fourier transform due to synchronization errors of interharmonics are analyzed. The time-domain averaging is investigated for the processing of harmonics in the framework of the IEC standards. A difference filter is proposed to detect interharmonics and can be compatible with the IEC standards. Simulations and the field results show the usefulness of the proposed methods.
The transurethral resection (TUR) is a standard technique in urological treatment procedures. Both, monopolar and bipolar electrosurgical systems, are used for TUR. Whereas electrical and physical processes in surgery surroundings are well understood for monopolar systems, there is no sufficient data base for the assessment of the processes with the use of bipolar systems. In this context a multi-electrode measuring system was developed to visualize the spatial potential distribution around bipolar electrosurgical devices as a first step to risk analysis. To simulate the anatomic surroundings of a transurethral surgery a cylinder filled with isotonic saline solution was used as a complexity reduced experimental environment.
The bipolar transurethral resection is a further development of monopolar transurethral resection, being the gold standard in surgical treatment of prostate and bladder diseases. To create the metrological basis for understanding of electrical and physical processes during bipolar transurethral resection an experimental set-up to visualize spatial potential distribution around bipolar devices was developed. A hardware based signal conditioning and specific undersampling are presented as data acquisition methods for a sampling rate up to 1 MS/s. These methods are compared with the possibilities of a high speed data acquisition card. For more than four measuring channels and depending on the output bandwidth of the electrosurgical generator either hardware based signal conditioning or specific undersampling is suggested.
Bipolar electrosurgical systems are used for the treatment of benign prostatic hyperplasia (BPH) in urology. In order to analyse electrothermal processes during surgery the power loss density distribution around a bipolar resectoscope is calculated out of the measured potential distribution in isotonic saline solution ex situ. During further analysis power loss density values act as input for the Penne's bioheat equation. To achieve results, which are as realistic as possible, a method to obtain power loss density values, depending on the observed tissue or medium in the operating field, is presented. Applying this method, the power loss density distribution in isotonic saline solution at 25 °C is compared to the distribution calculated for the average conductivity of biological tissue in the region of interest.
Untersuchung des Einflusses von Längsrissen in Drähten auf die Impedanz eines Wirbelstromsensors
(2012)
Induktive Bioimpedanzmessung – Verbesserte örtliche Auflösung durch geeignete Spulengeometrien
(2013)
Influencing Parameters on Measuring the Cross-Section Area of Hot Rolled Rods in Steel Industries
(2014)
Die transurethrale Resektion der Prostata (TURP) ist ein Verfahren der Elektrochirurgie innerhalb der Urologie. Thema der Arbeit ist die Entwicklung einer Methodik für realitätsnahe vergleichende Untersuchungen der elektrothermischen Vorgänge um Resektoskope zur bipolaren TURP. Die Relevanz dieses Themas liegt in der aktuellen Diskussion, ob elektrothermische Verletzungen eine mögliche Ursache urethraler Komplikationen darstellen. In diesem Kontext sind nicht die Vorgänge an der Resektionselektrode sondern in nicht behandelten Arealen des Operationsgebiets von Interesse. Bisher durchgeführte Untersuchungen konzentrieren sich auf monopolare Systeme. Untersuchte bipolare Elektrodenanordnungen unterscheiden sich allerdings von heutigen bipolaren Resektoskopen. Die vorhandenen Erkenntnisse sind deshalb nur äußerst eingeschränkt anwendbar. Informationen zu thermischen Vorgängen bezüglich Spätkomplikationen liegen nicht vor.
Der gewählte Ansatz aus messtechnischer Bestimmung der 3D Potentialverteilung ex situ sowie modellbasierter und numerischer Analyse der sich daraus ergebenden 3D Verlustleistungsdichteverteilung und der darauf beruhenden Temperaturberechnung im operationsnahen Gewebe ermöglicht ein auf die Realität übertragbares Ergebnis. Die berechnete Temperatur dient des Weiteren als Grundlage einer medizinischen Einschätzung hinsichtlich des Potentials elektrothermischer Verletzungen. Ergebnis der Arbeit ist, dass vergleichende Untersuchungen bipolarer Resektoskope mit der entwickelten Methodik durchführbar sind. Für die untersuchte bipolare Elektrodenanordnung erscheinen elektrothermische Verletzungen als Ursache urethraler Strikturen bei konservativer Betrachtung und unter durchschnittlichen Operationsbedingungen ohne intraoperative Komplikationen unwahrscheinlich.
Optimization of Encircling Eddy Current Sensors for Online Monitoring of Hot Rolled Round Steel Bars
(2014)
Modern manufacturing industries are continually working on quality enhancements for the hot rolling process of round products. One method for improving the finalisation of the rods is the implementation of an automatic size control system. As a result of these trends over the last few years, there has been an increasing demand for more accurate online measurements. Thus the reason for the research performed for this thesis. A particular challenge throughout this research was dealing with the temperature changes (up to 1200°C) from the in- and output of the fervent rolling stocks, and the effect this temperature changes had on the sensors. Furthermore, there is also high demand for developing fast and practical electronic measuring equipment, capable of measuring during high transport velocities (up to 120 m/s). The eddy current principle is just one of the very few methods available which can with-stand such harsh industrial environments. In fact, eddy current sensors are already being integrated into online monitoring tasks for hot rolling processes. The measurement uncertainty, however, is still considerably large for process control purposes. One reason for this lies within the ability for eddy current detectors to receive signals influenced by outward forces, i.e. forces dependent on its location, its geometry, the outside temperature and the material properties of a particular target. Thus the current accuracy for a cross-sectional area measurement, for example, is no higher than 1%. As a result, this thesis investigates the magnitude of all individual influential factors on the eddy current detectors, using model-based analysis techniques. The analytical model provides a solution for all rotationally symmetrical targets and the FEA model covers all of the other influencing parameters in a more time consuming manner. This thesis then provides different methods which are developed to separate the cross-sectional area measurement of a rod from all of the other influencing parameters. In addition, a material tracking approach for round products is developed. Two different kinds of prototypes, capable of measuring approximately 466 Tons of red-hot steel rods during the production process, are finally introduced in this thesis. The usefulness of the eddy current principle is validated by the provided field test results. The count accuracy for the identification of 2876 bars was found to be 99.93%, and the average measurement accuracy for the cross-sectional area experiments was reduced to ± 0.29 % when including all of the findings.
Die steigenden Anforderungen an den Umweltschutz bei möglichst niedrigen Kosten betreffen auch die öffentlichen Kanalnetze und Kläranlagen. Speziell die Kanalnetze sind über Jahrzehnte gewachsen, ohne dass kostengünstig eine genaue Bilanz ihrer Leistungsfähigkeit bis in ihre Segmente möglich war. Es fehlte vor allem in kleineren Systemen an Messwerten für die Transportmengen in Abhängigkeit der Witterung zur Beurteilung des Transportverhaltens der Einzelsegmente. Erst diese Messwerte ermöglichen eine mathematische Modellbildung mit Parametrierung und damit Ansätze für eine Optimierung. In diesem Beitrag wird der Prototyp eines neuartigen Sensors vorgestellt, der die gleichzeitige, kostengünstige und zeitbegrenzte Erfassung der Abwasserströme an verschiedenen Punkten im Kanalnetz ermöglichen soll. Die im Abwasserstrom befindlichen Teile des Sensors sind preiswerte mechanische Komponenten, die kostengünstig und einfach zu ersetzen sind. Die Erfassung der Strömungsgeschwindigkeit und der durchströmten Querschnittsfläche erfolgt mit Hilfe der sich an einem Störkörper einstellenden Druckverhältnisse.
In modernen Prüffeldern zur Warenendkontrolle dienen halbleitergesteuerte Frequenzumformer zur Einstellung der Drehzahl. Diese Systeme verursachen erhebliche Störungen der Strom- und Spannungssignale. Aus diesen Signalen müssen alle elektrischen Kenngrößen berechnet werden. Eine besondere Bedeutung haben dabei die Frequenz und Phasenlage. In diesem Beitrag wird ein mathematischer Algorithmus vorgestellt, der zur Berechnung von Frequenz und Phasenlage bei guter Unterdrückung dieser Störungen eingesetzt werden kann.
Im vorliegenden Beitrag wird das Phasen-Differenz-Verfahren zur Frequenzmessung der durch Rauschen gestörten Signale vorgestellt. Es wird gezeigt, dass Frequenzausreißer bei Anwendungen dieses Verfahrens entstehen, auch wenn das Signal-zu-Rausch-Verhältnis ausreichend groß ist. Die Ursachen der Frequenzausreißer werden analysiert. Zur Korrektur wird ein Lösungsansatz vorgeschlagen. Im Vergleich mit anderen Verfahren kann das verbesserte Phasen-Differenz-Verfahren die Frequenz der durch Rauschen gestörten Signale mit größerer Genauigkeit und vertretbarem Rechenaufwand berechnen.
Wirbelströme werden in der Mess- und Sensortechnik sehr erfolgreich benutzt, um berührungslos Risse und Abstände metallischer Halbzeuge zu bestimmen. Die Messung von Konturen ist mit diesem industrietauglichen Wirkprinzip bisher nicht realisiert worden. Hier werden häufig optische Messsysteme eingesetzt. Speziell bei glühenden Werkstücken oder bei Benetzung der Halbzeuge mit Bohremulsionen und Schneidölen steigt der Aufwand für den Einsatz optischer Systeme stark an. Messverfahren, die auf hochfrequenten Wirbelströmen basieren, sind aufgrund ihrer einfachen Aufbauten deutlich robuster und somit besser für diese Anwendung geeignet. Voruntersuchungen zeigten, dass mit dieser Methode schon kleine Geometrieabweichungen des Walzgutes von wenigen Mikrometern detektiert werden können. In diesem Beitrag werden zwei Möglichkeiten zur Messung der spektralen Impedanzbeeinflussung eines Messschwingkreises durch die Wirbelströme im Werkstück gegenübergestellt.
The production and deformation of perforated sheets introduces high levels of mechanical stress into the material. In a significant fraction, such stress levels lead to crack formation in the processed sheets. Additionally, the material might be thinned and weakened in the exposed areas; these areas tend to crack at any later dates. Currently no measuring device for the detection of such material cracks or narrowing in perforated sheet metals is in practical use. Such device should be able to test the deformed circumference of the processed sheets within the very limited time of the production cycles. This paper describes the physical principles and a metrological implementation of a potential method for fast crack detection in perforated sheet metals. Even a critical material thinning - prior to the formation of a crack - can be observed. The measuring task appears to be solvable on the basis of high frequency electromagnetic fields.
Die steigenden Anforderungen der fertigenden Industrie an Halbzeuge wie Stahl- und Aluminiumblech führen zu großen Anstrengungen bei der Entwicklung neuer und Verbesserung alter Walztechniken. Einen wesentlichen Einfluss auf die erreichbaren Flächentoleranzen der Bleche hat neben der Walzenform die Temperaturverteilung an der Walzenoberfläche.
Increasing demands from the manufacturing industry on semifinished products such as steel and aluminium plate are leading to greater efforts in the development of new and the improvement of existing rolling techniques. In addition to the shape of the roll, temperature distribution on the roll surface has a significant influence on the surface tolerances of the sheets which may be achieved.
The transurethral resection (TUR) is a standard technique in urological treatment procedures. Both, monopolar and bipolar electrosurgical systems, are used for TUR. Whereas electrical and physical processes in surgery surroundings are well understood for monopolar systems, there is no sufficient data base for the assessment of the processes with the use of bipolar systems. In this context a multi-electrode measuring system was developed to visualize the spatial potential distribution around bipolar electrosurgical devices as a first step to risk analysis. To simulate the anatomic surroundings of a transurethral surgery a cylinder filled with isotonic saline solution is used as a complexity reduced experimental environment. Investigations about time stability and a qualitative assessment of the experimental set-up show deviations of measured values less than 5%. This is sufficient for further analysis of calculated power loss density distributions based on measured potential distributions. The spatial potential distribution around a bipolar devices is presented by horizontal and vertical sections through the experimental environment.
Die transurethrale Resektion der Prostata (TUR-P) ist der Gold Standard für die endoskopisch-chirurgische Behandlung der Benignen Prostatahyperplasie (BPH). Unbekannt ist jedoch, ob bei der bipolaren TUR-P die Möglichkeit von elektrothermischen Verletzung von benachbartem nichtopertiertem Gewebe besteht. Grund hierfür könnten höhere Ausgangsleistungen der Chirurgie-Generatoren sein. Deshalb werden experimentell gemessene Werte der räumlichen Verlustleistungsdichte um ein bipolares Resektoskop als Quellterm für die Berechnung der Temperaturänderung im operationsnahen Gewebe verwendet. Die Temperaturberechnung basiert auf der numerischen Lösung der Wärmeleitungsgleichung nach Penne. Für die gewählten Randbedingungen und Eingabeparameter sind keine signifikanten Temperaturerhöhungen im Berechnungsgebiet am proximalen Ende des Resektoskop-Schaftes festzustellen. Um ein umfassendes Verständnis zu gewinnen sollen weiterführende Untersuchungen mit einer Variation der Randbedingungen und Eingabeparameter durchgeführt werden
In dieser Veröffentlichung wird ein Konzept vorgestellt, das es erlaubt die Topologie der Magnetfelder bei der „Magnetischen Induktionstomografie“ (MIT) durch geometrische Spulenkonstruktionen und Bestromungsmuster soweit zu verändern, um eine scharfe Lokalisierung von Objekten innerhalb des Raumes zu ermöglichen. Ziel ist dabei, die Empfindlichkeit im Messvolumen gleichmäßiger als in der bekannten MIT zu verteilen, sodass elektrisch leitfähige Objekte mit größerer Entfernung zwischen Sender- und Empfängereinheit mit nahezu gleich hoher Signalintensität detektiert werden können, wie Objekte in Sender- und Empfängernähe. Dabei soll die maximale Objektgröße, die noch zu detektieren ist, verkleinert und die Empfindlichkeit des Systems verbessert werden.
To analyze the electric field around bipolar resectoscopes, used in urology, in terms of reasons for late complications after a surgical treatment a flexible multielectrode system was developed to measure the 3-D potential distribution. A high spatial resolution is achieved with the least possible individual measurements under the conditions of a quasi-static electric field. A flexible arrangement and positioning of the measuring points in the vertical direction of the experimental environment enable an adjustable spatial resolution and the selection of the region of interest. The existing influence of the multielectrode system on the measuring results is described and a correction method is presented to achieve significant results. Thus, the multielectrode system is usable for a comparative study of bipolar resectoscopes varying in the arrangement of resection and return electrode.
LEDs gelten als umweltfreundliche Beleuchtungstechnik. Für die Massenanwendung arbeiten die LED-Hersteller an einer Senkung der Kosten bzw. einer Erhöhung der Ausbeute, insbesondere bei der aufwendigen LED-Kristallbeschichtung auf den Wafern. Während der Beschichtung (MOCVD) werden optische In-situ-Messgeräte zur Überwachung des Prozesses genutzt. Die hier vorgestellte Untersuchung beschäftigt sich mit dem Einfluss von Super-Photolumineszenz-Effekten bei einer möglichen In-situ-Prozesskontrolle in der MOCVD.
Wirbelstromsensoren sind in der industriellen Messtechnik stark verbreitet. Insbesondere bei der Herstellung warmgewalzter Halbzeuge können sie durch ihre Robustheit gegenüber Wasserdampf und hohen Walzguttemperaturen überzeugen. Ein noch offenes Feld ist die In-Situ‐Detektion von Rissen im Draht während des Walzprozesses bei Walzgeschwindigkeiten bis zu 100 m/s und Materialtemperaturen bis zu 1200 ℃. Im Folgenden soll mittels der Finiten-Elemente-Analyse untersucht werden, wie sich Längsrisse im Draht auf Oberflächenströme und damit auf deren magnetische Flussdichte auswirken. Ziel ist es, Aussagen über den Einfluss verschiedener Rissbreiten und Risstiefen auf die magnetische Flussdichte zu machen und so einen möglichen Effekt auf einen Wirbelstromsensor untersuchen zu können.
Gallium Nitride (GaN) and Indium Gallium Nitride (InGaN) have become important semiconductor materials for the LED lighting industry. Recently, a photoluminescence (PL) technique for direct in-situ characterization of GaN and InGaN layers during epitaxial growth in a planetary metalorganic vapor phase epitaxy (MOVPE) reactor was reported. The PL signals reveal – at the earliest possible stage – information about current layer thickness, temperature, composition, surface roughness, and self-absorption. Thus, the PL data is valuable for both controlling and optimizing the growth parameters, thereby promising both better devices and a better yield for the LED industry. This technical report describes an extension of this PL technique to close coupled showerhead (CCS) reactors with narrow optical viewports. In contrast to the wide aperture optics in previous investigations, a compact and all-fiber optical probe without voluminous lens optics, filter elements or beam splitters was used.
Editorial
Jörg Himmel, Olfa Kanoun, Thomas Seeger, Klaus Thelen IEEE Workshop on Industrial and Medical Measurement and Sensor Technology – SENSORICA 2016 1
Beiträge Jan Taro Svejda, Andreas Rennings, Daniel Erni A metamaterial based dual-resonant coil element for combined sodium/hydrogen MRI at 7 Tesla 2
Fabian Feldhaus, Ingo Schmitz, Thomas Seeger Emission spectroscopy based sensor developed for engine testing 13
Anne-Sophie Rother, Thomas Dietz, Peter Kohns, Georg Ankerhold Molecular laser-induced breakdown spectroscopy for elemental analysis 23
Johannes Kiefer, Andreas Bösmann, Peter Wasserscheid Quantitative measurement of complex substances dissolved in an ionic liquid using IR spectroscopy and chemometrics 32
Oliver Gieseler, Hubert Roth, Jürgen Wahrburg Methods to determine the scaling factor in X-ray images for exact preoperative planning in hip surgery 38
Erwin Gerz, Matthias Mende, Hubert Roth Development of an optical tracking system for a novel flexible and soft manipulator with controllable stiffness for minimal invasive surgery (MIS) 47
Jens Weidenmüller, Christian Walk, Özgü Dogan, Pierre Gembaczka, Alexander Stanitzki, Michael Görtz Telemetric multi-sensor system for medical applications – The approach 53
Inga-Maria Eichentopf, Martin Reufer Measurement and analysis of wavefront structures of diode lasers 59