TY  - CHAP
A1  - Ballmann, J.
A1  - Raatschen, Hans-Jürgen
A1  - Staat, Manfred
T1  - High stress intensities in focussing zones of waves
N2  - The propagation of mechanical waves in plates of isotropic elastic material is investigated. After a short introduction to the understanding of focussing of stress waves in a plate with a curved boundary the method of characteristics is applied to a plate of hyperelastic material. Using this method the propagation of acceleration waves is discussed. Based on this a numerical difference scheme is developed for solving initial-boundary-value problems and applied to two examples: propagation of a point disturbance in a homogeneously finitely strained non-linear elastic plate and geometrical focussing in al linear elastic plate.
KW  - Technische Mechanik
KW  - Wellen
KW  - mechanical waves
Y1  - 1985
U6  - http://dx.doi.org/10.1016/B978-0-444-42520-1.50015-3
ER  - 
TY  - CHAP
A1  - Kern, Alexander
A1  - Dikta, Gerhard
T1  - Probability of damage of electrical and electronic systems due to indirect lightning flashes - investigation of data from German insurance companies
N2  - In the presented paper data collected from the field related to damage statistics of electrical and electronic apparatus in household are reported and investigated. These damages (total number approx. 74000 cases), registered by five German insurance companies in 2005 and 2006, were adviced by customers as caused by lightning overvoltages. With the use of stochastical methods it is possible, to reasses the collected data and to distinguish between cases, which are with high probability caused by lightning overvoltages, and those, which are not. If there was an indication for a direct strike, this case was excluded, so the focus was only on indirect lightning flashes, i.e. only flashes to ground near the structure and flashes to or nearby an incoming service line were investigated. The data from the field contain the location of damaged apparatus (residence of the policy holder) and the distances of the nearest cloud-to-ground stroke to the location of the damage registered by the German lightning location network BLIDS at the date of damage. The statistical data along with some complementary numerical simulations allow to verify the correspondence of the Standards rules used for IEC 62305-2 with the field data and to define some correction needs. The results could lead to a better understanding whether a damage reported to an insurance company is really caused by indirect lightning, or not.
KW  - Blitzschutz
KW  - lightning flash
Y1  - 2009
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Tran, Thanh Ngoc
A1  - Pham, Phu Tinh
T1  - Limit and shakedown reliability analysis by nonlinear programming
N2  - 7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs.
KW  - Finite-Elemente-Methode
KW  - Limit analysis
KW  - Shakedown analysis
Y1  - 2008
ER  - 
TY  - CHAP
A1  - Tran, Thanh Ngoc
A1  - Pham, Phu Tinh
A1  - Staat, Manfred
T1  - Reliability analysis of shells based on direct plasticity methods
N2  - Abstracts der CD-Rom Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) 30.06. - 04.07.2008 Venedig, Italien. 2 Seiten Zusammenfassung der Autoren mit graph. Darst. und Literaturverzeichnis
N2  - Abstracts of the Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) June 30th - July, 4th 2008, Venice, Italy. 2 pages with abstracts of the authors, Ill. and references.
KW  - Finite-Elemente-Methode
KW  - Limit analysis
KW  - Shakedown analysis
KW  - First-order reliability method
KW  - second-order reliability method
KW  - Sensitivity
Y1  - 2008
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Szelinski, E.
A1  - Heitzer, Michael
T1  - Kollapsanalyse von längsfehlerbehafteten Rohren und Behältern
T1  - Collapse analysis of longitudinally flawed pipes and vessels
N2  - Es werden verbesserte Kollapsanalysen von dickwandigen, mit axialen Oberflächenfehlern behafteten Rohren und Behältern vorgeschlagen.
KW  - Druckbehälter
KW  - Stahl
KW  - Druckbelastung
KW  - Druckbeanspruchung
KW  - Rohr
KW  - Rohrbruch
KW  - Fehlerstellen
KW  - pipes
KW  - vessels
KW  - load limit
KW  - burst tests
KW  - burst pressure
KW  - flaw
Y1  - 2001
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
A1  - Reinders, H.
A1  - Schubert, F.
T1  - Einspielen und Ratchetting bei Zug- und Torsionsbelastung: Analyse und Experimente
T1  - Shakedown and ratchetting under tension-torsion loadings: analysis and experiments
N2  - Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der klassischen Plastizitätstheorie, die neben ausreichender Verformbarkeit keine einschränkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle für Details der Lastgeschichte und des Stoffverhaltens. Eine FEM-basierte Traglast- und Einspielanalyse für ideal plastisches Material wurde auf ein kinematisch verfestigendes Materialgesetz erweitert und in das Finite Element Programm PERMAS implementiert. In einem einfachen Zug-Torsionsexperiment wurde eine Hohlprobe mit konstanter Torsion und zyklischer Zugbelastung beansprucht, um die neue Implementierung zu verifizieren. Es konnte gezeigt werden, dass die Einspielanalyse gut mit den experimentellen Ergebnissen übereinstimmt. Bei Verfestigung lassen sich wesentlich größere Sicherheiten nachweisen. Dieses Potential bedarf weiterer experimenteller Absicherung. Parallel dazu ist die Eisnpieltheorie auf fortschrittliche Verfestigungsansätze zu erweitern.
KW  - Zug-Druck-Beanspruchung
KW  - Einspielen <Werkstoff>
KW  - Ratcheting
KW  - Torsion
KW  - Zug-Druck-Belastung
KW  - Torsionsbelastung
KW  - shakedown
KW  - ratchetting
KW  - tension–torsion loading
Y1  - 2001
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
A1  - Hicken, E. F.
T1  - LISA - ein europäisches Projekt zur FEM-basierten Traglast- und Einspielanalyse
T1  - LISA - a European project for FEM-based limit and shakedown analysis
N2  - Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der Plastizität, die neben ausreichender Verformbarkeit keine einschränkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle für Details der Lastgeschichte und des Stoffverhaltens. Anders als die klassische Behandlung nichtlinearer Probleme der Strukturmechanik führt die Methode auf Optimierungsprobleme. Diese sind bei realistischen FEM-Modellen sehr groß. Das hat die industrielle Anwendung der Traglast- und Einspielanalysen stark verzögert. Diese Situation wird durch das Brite-EuRam Projekt LISA grundlegend geändert. In LISA entsteht auf der Basis des industriellen FEM-Programms PERMAS ein Verfahren zur direkten Berechnung der Tragfähigkeit duktiler Strukturen. Damit kann der Betriebsbereich von Komponenten und Bauwerken auf den plastischen Bereich erweitert werden, ohne den Aufwand gegenüber elastischen Analysen wesentlich zu erhöhen. Die beachtlichen Rechenzeitgewinne erlauben Parameterstudien und die Berechnung von Interaktionsdiagrammen, die einen schnellen Überblick über mögliche Betriebsbereiche vermitteln. Es zeigt sich, daß abhängig von der Komponente und ihren Belastungen teilweise entscheidende Sicherheitsgewinne zur Erweiterung der Betriebsbereiche erzielt werden können. Das Vorgehen erfordert vom Anwender oft ein gewisses Umdenken. Es werden keine Spannungen berechnet, um damit Sicherheit und Lebensdauer zu interpretieren. Statt dessen berechnet man direkt die gesuchte Sicherheit. Der Post-Prozessor wird nur noch zur Modell- und Rechenkontrolle benötigt. Das Vorgehen ist ähnlich der Stabilitätsanalyse (Knicken, Beulen). Durch namhafte industrielle Projektpartner werden Validierung und die Anwendbarkeit auf eine breite Palette technischer Probleme garantiert. Die ebenfalls in LISA entwickelten Zuverlässigkeitsanalysen sind nichlinear erst auf der Basis direkter Verfahren effektiv möglich. Ohne Traglast- und Einspielanalyse ist plastische Strukturoptimierung auch heute kaum durchführbar. Auf die vorgesehenen Erweiterungen der Werkstoffmodellierung für nichtlineare Verfestigung und für Schädigung konnte hier nicht eingegangen werden. Es herrscht ein deutlicher Mangel an Experimenten zum Nachweis der Grenzen zwischen elastischem Einspielen und dem Versagen durch LCF oder durch Ratchetting.
KW  - Einspielen <Werkstoff>
KW  - Traglast
KW  - Finite-Elemente-Methode
KW  - LISA
KW  - limit analysis
KW  - shakedown analysis
Y1  - 1999
ER  - 
TY  - CHAP
A1  - Lang, H.
A1  - Wirtz, K.
A1  - Heitzer, Michael
A1  - Staat, Manfred
A1  - Oettel, R.
T1  - Zyklische Einspielversuche zur Verifikation von Shakedown-Analysen mittels FEM
T1  - Cyclic plastic deformation test to verify FEM-based shakedown analysis
N2  - Im Rahmen von Ermüdungsanalysen ist nachzuweisen, daß die thermisch bedingten fortschreitenden Deformationen begrenzt bleiben. Hierzu ist die Abgrenzung des Shakedown-Bereiches (Einspielen) vom Ratchetting-Bereich (fortschreitende Deformation) von Interesse. Im Rahmen eines EU-geförderten Forschungsvorhabens wurden Experimente mit einem 4-Stab-Modell durchgeführt. Das Experiment bestand aus einem wassergekühlten inneren Rohr und drei isolierten und beheizbaren äußeren Probestäben. Das System wurde durch alternierende Axialkräfte, denen alternierende Temperaturen an den äußeren Stäben überlagert wurden, belastet. Die Versuchsparameter wurden teilweise nach vorausgegangenen Einspielanalysen gewählt. Während der Versuchsdurchführung wurden Temperaturen und Dehnungen zeitabhängig gemessen. Begleitend und nachfolgend zur Versuchsdurchführung wurden die Belastungen und die daraus resultierenden Beanspruchungen nachvollzogen. Bei dieser inkrementellen elasto-plastischen Analyse mit dem Programm ANSYS wurden unterschiedliche Werkstoffmodelle angesetzt. Die Ergebnisse dieser Simulationsberechnung dienen dazu, die Shakedown-Analysen mittels FE-Methode zu verifizieren.
KW  - Einspielen <Werkstoff>
KW  - Traglast
KW  - Finite-Elemente-Methode
KW  - Shakedown
KW  - shakedown analysis
KW  - plastic deformation
Y1  - 1999
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
T1  - Limit and shakedown analysis for plastic design
N2  - Limit and shakedown theorems are exact theories of classical plasticity for the direct computation of safety factors or of the load carrying capacity under constant and varying loads. Simple versions of limit and shakedown analysis are the basis of all design codes for pressure vessels and pipings. Using Finite Element Methods more realistic modeling can be used for a more rational design. The methods can be extended to yield optimum plastic design. In this paper we present a first implementation in FE of limit and shakedown analyses for perfectly plastic material. Limit and shakedown analyses are done of a pipe–junction and a interaction diagram is calculated. The results are in good correspondence with the analytic solution we give in the appendix.
KW  - Einspielen <Werkstoff>
KW  - Traglast
KW  - Finite-Elemente-Methode
KW  - Traglastanalyse
KW  - Einspielanalyse
KW  - FEM
KW  - limit analysis
KW  - shakedown analysis
Y1  - 1997
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
T1  - Direkte FEM-Berechnung der Tragfähigkeit hochbeanspruchter passiver Komponenten
T1  - Direct FEM-computation of load carrying capacity of highly loaded passive components
N2  - Genaue Kenntnis der Spannungen und Verformungen in passiven Komponenten gewinnt man mit detailierten inelastischen FEM Analysen. Die lokale Beanspruchung läßt sich aber nicht direkt mit einer Beanspruchbarkeit im strukturmechanischen Sinne vergleichen. Konzentriert man sich auf die Frage nach der Tragfähigkeit, dann vereinfacht sich die Analyse. Im Rahmen der Plastizitätstheorie berechnen Traglast- und Einspielanalyse die tragbaren Lasten direkt und exakt. In diesem Beitrag wird eine Implementierung der Traglast- und Einspielsätze in ein allgemeines FEM Programm vorgestellt, mit der die Tragfähigkeit passiver Komponenten direkt berechnet wird. Die benutzten Konzepte werden in Bezug auf die übliche Strukturanalyse erläutert. Beispiele mit lokal hoher Beanspruchung verdeutlichen die Anwendung der FEM basierten Traglast- und Einspielanalysen. Die berechneten Interaktionsdiagramme geben einen guten Überblick über die möglichen Betriebsbereiche passiver Komponenten. Die Traglastanalyse bietet auch einen strukturmechanischen Zugang zur Kollapslast rißbehafteter Komponenten aus hochzähem Material.
KW  - Finite-Elemente-Methode
KW  - Tragfähigkeit
KW  - FEM-Programm
KW  - FEM-computation
KW  - load carrying capacity
Y1  - 1997
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, M.
A1  - Hicken, E. F.
T1  - LISA, ein europäisches Projekt zur direkten Berechnung der Tragfähigkeit duktiler Strukturen
N2  - Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der Plastizität, die neben ausreichender Verformbarkeit keine einschränkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle für Details der Lastgeschichte und des Stoffverhaltens. Anders als die klassische Behandlung nichtlinearer Probleme der Strukturmechanik führt die Methode auf Optimierungsprobleme. Diese sind bei realistischen FEM-Modellen sehr groß. Das hat die industrielle Anwendung der Traglast- und Einspielanalysen stark verzögert. Diese Situation wird durch das Brite-EuRam Projekt LISA grundlegend geändert. Die Autoren möchten der Europäischen Kommission an dieser Stelle für die Förderung ausdrücklich danken. In LISA entsteht auf der Basis des industriellen FEM-Programms PERMAS ein Verfahren zur direkten Berechnung der Tragfähigkeit duktiler Strukturen. Damit kann der Betriebsbereich von Komponenten und Bauwerken auf den plastischen Bereich erweitert werden, ohne den Aufwand gegenüber elastischen Analysen wesentlich zu erhöhen. Die beachtlichen Rechenzeitgewinne erlauben Parameterstudien und die Berechnung von Interaktionsdiagrammen, die einen schnellen Überblick über mögliche Betriebsbereiche vermitteln. Es zeigt sich, daß abhängig von der Komponente und ihren Belastungen teilweise entscheidende Sicherheitsgewinne zur Erweiterung der Betriebsbereiche erzielt werden können. Das Vorgehen erfordert vom Anwender oft ein gewisses Umdenken. Es werden keine Spannungen berechnet, um damit Sicherheit und Lebensdauer zu interpretieren. Statt dessen berechnet man direkt die gesuchte Sicherheit. Der Post-Prozessor wird nur noch zur Modell- und Rechenkontrolle benötigt. Das Vorgehen ist änhlich der Stabilitätsanalyse (Knicken, Beulen). Durch namhafte industrielle Projektpartner werden Validierung und die Anwendbarkeit auf eine breite Palette technischer Probleme garantiert. Die ebenfalls in LISA geplante Zuverlässigkeitsanalyse ist erst auf der Basis direkter Verfahren effektiv möglich. Ohne Traglast- und Einspielanalyse ist plastische Strukturoptimierung auch heute kaum durchführbar.
KW  - Finite-Elemente-Methode
KW  - Traglastanalyse
KW  - Einspielanalyse
KW  - limit analysis
KW  - shakedown analysis
Y1  - 1998
ER  - 
TY  - CHAP
A1  - Heitzer, M.
A1  - Staat, Manfred
T1  - Direct FEM approach to design-by-analysis of pressurized components
N2  - Abstracts of the ACHEMA 2000 - International Meeting on Chemical Engineering, Environmental Protection and Biotechnology, May 22 - 27, 2000. Frankfurt am Main. Achema 2000 : special edition / Linde. [Ed.: Linde AG. Red.: Volker R. Leski]. - Wiesbaden : Linde AG, 2000. - 56 p. : Ill., . - pp: 79 - 81
N2  - Abstracts der ACHEMA 2000 - International Meeting on Chemical Engineering, Environmental Protection and Biotechnology, May 22 - 27, 2000. Frankfurt am Main.
KW  - Finite-Elemente-Methode
KW  - Finite-Elemente-Methode
KW  - limit analysis
KW  - shakedown analysis
Y1  - 2000
ER  - 
TY  - CHAP
A1  - Tran, Thanh Ngoc
A1  - Staat, Manfred
A1  - Kreißig, R.
T1  - Finite element shakedown and limit reliability analysis of thin shells
N2  - A procedure for the evaluation of the failure probability of elastic-plastic thin shell structures is presented. The procedure involves a deterministic limit and shakedown analysis for each probabilistic iteration which is based on the kinematical approach and the use the exact Ilyushin yield surface. Based on a direct definition of the limit state function, the non-linear problems may be efficiently solved by using the First and Second Order Reliabiblity Methods (Form/SORM). This direct approach reduces considerably the necessary knowledge of uncertain technological input data, computing costs and the numerical error. In: Computational plasticity / ed. by Eugenio Onate. Dordrecht: Springer 2007. VII, 265 S. (Computational Methods in Applied Sciences ; 7) (COMPLAS IX. Part 1 . International Center for Numerical Methods in Engineering (CIMNE)). ISBN 978-1-402-06576-7  S. 186-189
KW  - Finite-Elemente-Methode
KW  - Limit analysis
KW  - shakedown analysis
KW  - Exact Ilyushin yield surface
KW  - Random variable
KW  - First Order Reliabiblity Method
Y1  - 2007
ER  - 
TY  - CHAP
A1  - Tran, Thanh Ngoc
A1  - Staat, Manfred
A1  - Kreißig, R.
T1  - Calculation of load carrying capacity of shell structures with elasto-plastic material by direct methods
N2  - Proceedings of the International Conference on Material Theory and Nonlinear Dynamics. MatDyn. Hanoi, Vietnam, Sept. 24-26, 2007, 8 p. In this paper, a method is introduced to determine the limit load of general shells using the finite element method. The method is based on an upper bound limit and shakedown analysis with elastic-perfectly plastic material model. A non-linear constrained optimisation problem is solved by using Newton’s method in conjunction with a penalty method and the Lagrangean dual method. Numerical investigation of a pipe bend subjected to bending moments proves the effectiveness of the algorithm.
KW  - Finite-Elemente-Methode
Y1  - 2007
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Ballmann, J.
T1  - Fundamental aspects of numerical methods for the propagation of multi-dimensional nonlinear waves in solids
T2  - Nonlinear hyperbolic equations : theory, computations methods, and applications ; proceedings of the 2nd International Conference on Nonlinear Hyperbolic Problems, Aachen
N2  - The nonlinear scalar constitutive equations of gases lead to a change in sound speed from point to point as would be found in linear inhomogeneous (and time dependent) media. The nonlinear tensor constitutive equations of solids introduce the additional local effect of solution dependent anisotropy. The speed of a wave passing through a point changes with propagation direction and its rays are inclined to the front. It is an open question whether the widely used operator splitting techniques achieve a dimensional splitting with physically reasonable results for these multi-dimensional problems. May be this is the main reason why the theoretical and numerical investigations of multi-dimensional wave propagation in nonlinear solids are so far behind gas dynamics. We hope to promote the subject a little by a discussion of some fundamental aspects of the solution of the equations of nonlinear elastodynamics. We use methods of characteristics because they only integrate mathematically exact equations which have a direct physical interpretation.
KW  - Nichtlineare Welle
KW  - Nichtlineare Gleichung
KW  - Festkörper
KW  - Elastodynamik
KW  - Multi-dimensional wave propagation
KW  - nonlinear solids
KW  - nonlinear tensor constitutive equation
Y1  - 1989
SP  - 574
EP  - 588
ER  - 
TY  - CHAP
A1  - Staat, Manfred
T1  - Problems and chances for probabilistic fracture mechanics in the analysis of steel pressure boundary reliability. - Überarb. Ausg.
N2  - In: Technical feasibility and reliability of passive safety systems for nuclear power plants. Proceedings of an Advisory Group Meeting held in Jülich, 21-24 November 1994. - Vienna , 1996. - Seite: 43 - 55 IAEA-TECDOC-920 Abstract: It is shown that the difficulty for probabilistic fracture mechanics (PFM) is the general problem of the high reliability of a small population. There is no way around the problem as yet. Therefore what PFM can contribute to the reliability of steel pressure boundaries is demon­strated with the example of a typical reactor pressure vessel and critically discussed. Although no method is distinguishable that could give exact failure probabilities, PFM has several addi­tional chances. Upper limits for failure probability may be obtained together with trends for design and operating conditions. Further, PFM can identify the most sensitive parameters, improved control of which would increase reliability. Thus PFM should play a vital role in the analysis of steel pressure boundaries despite all shortcomings.
KW  - Bruchmechanik
KW  - probabilistic fracture mechanics
KW  - PFM
Y1  - 2006
ER  - 
TY  - GEN
A1  - Staat, Manfred
A1  - Barry, Steve
T1  - Continuum Mechanics with an Introduction to the Finite Element Method / Steve Barry; Manfred Staat. With extensions by Manfred Staat.
N2  - Contents: 1 Introduction 2 One Dimensional Continuum Mechanics 3 Tensors 4 Three Dimensional Stress and Strain 5 Conservation Laws 6 Contiunuum Modelling 7 Plain Problems 8 Questions 9 Reference Information
KW  - Technische Mechanik
KW  - Finite-Elemente-Methode
Y1  - 2006
ER  - 
TY  - GEN
A1  - Staat, Manfred
T1  - Engineering Mechanics. Lecture Notes. 2nd edition, translation of the 3rd corrected and extended German edition of "Technische Mechanik"
N2  - English translation of the corrected lectures notes of Sebastian Krämer. Contents 0 Introduction to Mechanics 1 Statics of Rigid Bodies 2 Elastostatics (Strength of Materials) 3 Kinematics 4 Kinetics Literature
KW  - Technische Mechanik
KW  - Mechanics
KW  - Statics
KW  - Elastostatics
KW  - Kinematics
KW  - Kinetics
Y1  - 2006
ER  - 
TY  - GEN
A1  - Staat, Manfred
T1  - Technische Mechanik. Vorlesungsmitschrift. Korrigierter Nachdr. der 3. Aufl.
N2  - Überarbeitete, korrigierte und ergänzte Version einer Vorlesungsmitschrift von Sebastian Krämer. 172 S. Inhaltsverzeichnis 0 Einführung in die Mechanik 1 Statik starrer Körper 2 Elastostatik (Festigkeitslehre) 3 Kinematik 4 Kinetik Literatur
KW  - Technische Mechanik
Y1  - 2006
ER  - 
TY  - CHAP
A1  - Lei, Yu
A1  - Mulchandani, Priti
A1  - Chen, Wilfred
A1  - Mulchandani, Ashok
T1  - Biosensor for direct determination of fenitrothion and EPN using recombinant Pseudomonas putida JS444 with surface expressed organophosphorus hydrolase. 1. modified clark oxygen electrode
N2  - This paper reports a first microbial biosensor for rapid and cost-effective determination of organophosphorus pesticides fenitrothion and EPN. The biosensor consisted of recombinant PNP-degrading/oxidizing bacteria Pseudomonas putida JS444 anchoring and displaying organophosphorus hydrolase (OPH) on its cell surface as biological sensing element and a dissolved oxygen electrode as the transducer. Surfaceexpressed OPH catalyzed the hydrolysis of fenitrothion and EPN to release 3-methyl-4-nitrophenol and p-nitrophenol, respectively, which were oxidized by the enzymatic machinery of Pseudomonas putida JS444 to carbon dioxide while consuming oxygen, which was measured and correlated to the concentration of organophosphates. Under the optimum operating conditions, the biosensor was able to measure as low as 277 ppb of fenitrothion and 1.6 ppm of EPN without interference from phenolic compounds and other commonly used pesticides such as carbamate pesticides, triazine herbicides and organophosphate pesticides without nitrophenyl substituent. The applicability of the biosensor to lake water was also demonstrated.
KW  - Biosensor
KW  - Organophosphorus
KW  - fenitrothion
KW  - EPN
KW  - biosensor
KW  - Pseudomonas putida
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1573
ER  - 
TY  - CHAP
A1  - Baronas, Romas
A1  - Ivanauskas, Feliksas
A1  - Kulys, Juozas
T1  - Mathematical modeling of biosensors based on an array of enzyme microreactors
N2  - This paper presents a two-dimensional-in-space mathematical model of biosensors based on an array of enzyme microreactors immobilised on a single electrode. The modeling system acts under amperometric conditions. The microreactors were modeled by particles and by strips. The model is based on the diffusion equations containing a nonlinear term related to the Michaelis-Menten kinetics of the enzymatic reaction. The model involves three regions: an array of enzyme microreactors where enzyme reaction as well as mass transport by diffusion takes place, a diffusion limiting region where only the diffusion takes place, and a convective region, where the analyte concentration is maintained constant. Using computer simulation, the influence of the geometry of the microreactors and of the diffusion region on the biosensor response was investigated. The digital simulation was carried out using the finite difference technique.
KW  - Biosensor
KW  - Reaction-diffusion
KW  - modeling biosensor
KW  - microreactor
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1569
ER  - 
TY  - CHAP
A1  - Barek, Jiri
A1  - Fischer, Jan
A1  - Navratil, Tomas
A1  - Peckova, Karolina
A1  - Yosypchuk, Bogdan
T1  - Silver solid amalgam electrodes as sensors for chemical carcinogens
N2  - The applicability of differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV) at a non-toxic meniscus-modified silver solid amalgam electrode (m-AgSAE) for the determination of trace amounts of genotoxic substances was demonstrated on the determination of micromolar and submicromolar concentrations of 3-nitrofluoranthene using methanol - 0.01 mol L-1 NaOH (9:1) mixture as a base electrolyte and of Ostazine Orange using 0.01 mol L-1 NaOH as a base electrolyte.
KW  - Biosensor
KW  - Solid amalgam electrodes
KW  - voltammetry
KW  - carcinogens
KW  - 3-nitrofluoranthene
KW  - Ostazine Orange
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1554
ER  - 
TY  - CHAP
A1  - Arida, Hassan A.
A1  - Kloock, Joachim P.
A1  - Schöning, Michael Josef
T1  - Novel organic membrane-based thin-film microsensors for the determination of heavy metal cations
N2  - A first step towards the fabrication and electrochemical evaluation of thin-film microsensors based on organic PVC membranes for the determination of Hg(II), Cd(II), Pb(II) and Cu(II) ions in solutions has been realised. The membrane-coating mixture used in the preparation of this new type of microsensors is incorporating PVC as supporting matrix, o-nitrophenyloctylether (o-NPOE) as solvent mediator and a recently synthesized Hg[dimethylglyoxime(phene)]2+ and Bis-(4-hydroxyacetophenone)-ethylenediamine as electroactive materials for Hg(II) and Cd(II), respectively. A set of three commercialised ionophores for Cd(II), Pb(II) and Cu(II) has been also used for comparison. Thin-film microsensors based on these membranes showed a Nernstian response of slope (26-30 mV/dec.) for the respective tested cations. The potentiometric response characteristics (linear range, pH range, detection limit and response time) are comparable with those obtained by conventional membranes as well as coated wire electrodes prepared from the same membrane. The realisation of the new organic membrane-based thin-film microsensors overcomes the problem of an insufficient selectivity of solid-state-based thinfilm sensors.
KW  - Biosensor
KW  - Heavy metal detection
KW  - thin-film microsensors
KW  - organic PVC membranes
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1545
ER  - 
TY  - CHAP
A1  - Pijanowska, Dorota G.
A1  - Remiszewska, Elzbieta
T1  - pH-based detection of phenylalnine by potentiometric and colorimetric methods
N2  - In this paper, methods of sample preparation for potentiometric measurement of phenylalanine are presented. Basing on the spectrophotometric measurements of phenylalanine, the concentrations of reagents of the enzymatic reaction (10 mM L-Phe, 0,4 mM NAD+, 2U L-PheDH) were determined. Then, the absorption spectrum of the reaction product, NADH, was monitored (maximum peak at 340 nm). The results obtained by the spectrophotometric method were compared with the results obtained by the colourimetry, using pH indicators. The above-mentioned two methods will be used as references for potentiometric measurements of phenylalanine concentration.
KW  - Biosensor
KW  - Phenylalanine determination
KW  - enzymatic methods
KW  - pH-based biosensing
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1536
ER  - 
TY  - CHAP
A1  - Katz, Eugenii
A1  - Willner, Itamar
T1  - Magneto-controlled quantized electron transfer to surface-confined redox units and metal nanoparticles
N2  - Hydrophobic magnetic nanoparticles (NPs) consisting of undecanoate-capped magnetite (Fe3O4, average diameter ca. 5 nm) are used to control quantized electron transfer to surface-confined redox units and metal NPs. A two-phase system consisting of an aqueous electrolyte solution and a toluene phase that includes the suspended undecanoatecapped magnetic NPs is used to control the interfacial properties of the electrode surface. The attracted magnetic NPs form a hydrophobic layer on the electrode surface resulting in the change of the mechanisms of the surface-confined electrochemical processes. A quinone-monolayer modified Au electrode demonstrates an aqueous-type of the electrochemical process (2e-+2H+ redox mechanism) for the quinone units in the absence of the hydrophobic magnetic NPs, while the attraction of the magnetic NPs to the surface results in the stepwise single-electron transfer mechanism characteristic of a dry nonaqueous medium. Also, the attraction of the hydrophobic magnetic NPs to the Au electrode surface modified with Au NPs (ca. 1.4 nm) yields a microenvironment with a low dielectric constant that results in the single-electron quantum charging of the Au NPs.
KW  - Biosensor
KW  - Nanoparticles
KW  - magnetic particles
KW  - quantum charging
KW  - modified electrode
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1528
ER  - 
TY  - CHAP
A1  - Spannhake, Jan
A1  - Schulz, Olaf
A1  - Helwig, Andreas
A1  - Krenkow, Angelika
A1  - Müller, Gerhard
A1  - Doll, Theodor
T1  - High-temperature MEMS heater platforms: long-term performance of metal and semiconductor heater materials
N2  - Micromachined thermal heater platforms offer low electrical power consumption and high modulation speed, i.e. properties which are advantageous for realizing nondispersive infrared (NDIR) gas- and liquid monitoring systems. In this paper, we report on investigations on silicon-on-insulator (SOI) based infrared (IR) emitter devices heated by employing different kinds of metallic and semiconductor heater materials. Our results clearly reveal the superior high-temperature performance of semiconductor over metallic heater materials. Long-term stable emitter operation in the vicinity of 1300 K could be attained using heavily antimony-doped tin dioxide (SnO2:Sb) heater elements.
KW  - Biosensor
KW  - Hotplate
KW  - heater metallisation
KW  - high-temperature stability
KW  - electro-migration
KW  - doped silicon
KW  - doped metal oxide
KW  - antimony doped tin oxide
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1513
ER  - 
TY  - CHAP
A1  - Tymecki, Lukasz
A1  - Glab, Stanislaw
A1  - Koncki, Robert
T1  - Miniaturized, planar ion-selective electrodes fabricated by means of thick-film  technology
N2  - Various planar technologies are employed for developing solid-state sensors having low cost, small size and high reproducibility; thin- and thick-film technologies are most suitable for such productions. Screen-printing is especially suitable due to its simplicity, low-cost, high reproducibility and efficiency in large-scale production. This technology enables the deposition of a thick layer and allows precise pattern control. Moreover, this is a highly economic technology, saving large amounts of the used inks. In the course of repetitions of the film-deposition procedure there is no waste of material due to additivity of this thick-film technology. Finally, the thick films can be easily and quickly deposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodes based on ionophores as well as crystalline ion-selective materials dedicated for potentiometric measurements are demonstrated. Analytical parameters of these sensors are comparable with those reported for conventional potentiometric electrodes. All mentioned thick-film strip electrodes have been totally fabricated in only one, fully automated thickfilm technology, without any additional manual, chemical or electrochemical steps. In all cases simple, inexpensive, commercially available materials, i.e. flexible, plastic substrates and easily cured polymer-based pastes were used.
KW  - Biosensor
KW  - Potentiometry
KW  - thick-film technology
KW  - screen-printing
KW  - ion-selective electrodes
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1506
ER  - 
TY  - CHAP
A1  - Bukhari, Syed Faisal Ahmed
A1  - Yang, Wuqiang
T1  - Multi-interface level sensors and new development in monitoring and control of oil separators
N2  - In the oil industry, huge saving may be made if suitable multi-interface level measurement systems are employed for effectively monitoring crude oil separators and efficient control of their operation. A number of techniques, e.g. externally mounted displacers, differential pressure transmitters and capacitance rod devices, have been developed to measure the separation process with gas, oil, water and other components. Because of the unavailability of suitable multi-interface level measurement systems, oil separators are currently operated by the trial-and-error approach. In this paper some conventional techniques, which have been used for level measurement in industry, and new development are discussed.
KW  - Biosensor
KW  - Level sensor
KW  - multi-interface measurement
KW  - electrical capacitance tomography
KW  - ECT
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1498
ER  - 
TY  - CHAP
A1  - Pijanowska, Dorota G.
A1  - Remiszewska, Elzbieta
A1  - Pederzolli, Cecilia
A1  - Lunelli, Lorenzo
A1  - Vendano, Michele
A1  - Canteri, Roberto
A1  - Dudzinski, Konrad
A1  - Kruk, Jerzy
A1  - Torbicz, Wladyslaw
T1  - Surface modification for microreactor fabrication
N2  - In this paper, methods of surface modification of different supports, i.e. glass and polymeric beads for enzyme immobilisation are described. The developed method of enzyme immobilisation is based on Schiff’s base formation between the amino groups on the enzyme surface and the aldehyde groups on the chemically modified surface of the supports. The surface of silicon modified by APTS and GOPS with immobilised enzyme was characterised by atomic force microscopy (AFM), time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and infrared spectroscopy (FTIR). The supports with immobilised enzyme (urease) were also tested in combination with microreactors fabricated in silicon and Perspex, operating in a flow-through system. For microreactors filled with urease immobilised on glass beads (Sigma) and on polymeric beads (PAN), a very high and stable signal (pH change) was obtained. The developed method of urease immobilisation can be stated to be very effective.
KW  - Biosensor
KW  - Microreactors
KW  - surface modification
KW  - enzyme immobilisation
KW  - lab-on-a-chip
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1480
ER  - 
TY  - CHAP
A1  - Platen, Johannes
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
T1  - Microstructured Nanostructures – nanostructuring by means of conventional photolithography and layer-expansion technique
N2  - A new and simple method for nanostructuring using conventional photolithography and layer expansion or pattern-size reduction technique is presented, which can further be applied for the fabrication of different nanostructures and nano-devices. The method is based on the conversion of a photolithographically patterned metal layer to a metal-oxide mask with improved pattern-size resolution using thermal oxidation. With this technique, the pattern size can be scaled down to several nanometer dimensions. The proposed method is experimentally demonstrated by preparing nanostructures with different configurations and layouts, like circles, rectangles, trapezoids, “fluidic-channel”-, “cantilever”- and meander-type structures.
KW  - Biosensor
KW  - Nanostructuring
KW  - layer expansion
KW  - pattern-size reduction
KW  - self-aligned patterning
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1477
ER  - 
TY  - CHAP
A1  - Förster, Arnold
A1  - Stock, Jürgen
A1  - Montanari, Simone
A1  - Lepsa, Mihail Ion
A1  - Lüth, Hans
T1  - Fabrication and characterisation of GaAs Gunn Diode Chips for applications at 77 GHz in automotive industry
N2  - GaAs-based Gunn diodes with graded AlGaAs hot electron injector heterostructures have been developed under the special needs in automotive applications. The fabrication of the Gunn diode chips was based on total substrate removal and processing of integrated Au heat sinks. Especially, the thermal and RF behavior of the diodes have been analyzed by DC, impedance and S-parameter measurements. The electrical investigations have revealed the functionality of the hot electron injector. An optimized layer structure could fulfill the requirements in adaptive cruise control (ACC) systems at 77 GHz with typical output power between 50 and 90 mW.
KW  - Biosensor
KW  - Gunn diode
KW  - microwave generation
KW  - GaAs hot electron injector
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1462
ER  - 
TY  - CHAP
A1  - Rabner, Arthur
A1  - Shacham, Yosi
T1  - A concept for a sensitive micro total analysis system for high throughput fluorescence imaging
N2  - This paper discusses possible methods for on-chip fluorescent imaging for integrated bio-sensors. The integration of optical and electro-optical accessories, according to suggested methods, can improve the performance of fluorescence imaging. It can boost the signal to background ratio by a few orders of magnitudes in comparison to conventional discrete setups. The methods that are present in this paper are oriented towards building reproducible arrays for high-throughput micro total analysis systems (µTAS). The first method relates to side illumination of the fluorescent material placed into microcompartments of the lab-on-chip. Its significance is in high utilization of excitation energy for low concentration of fluorescent material. The utilization of a transparent µLED chip, for the second method, allows the placement of the excitation light sources on the same optical axis with emission detector, such that the excitation and emission rays are directed controversly. The third method presents a spatial filtering of the excitation background.
KW  - Biosensor
KW  - Fluorescence
KW  - imaging
KW  - lab-on-chip
KW  - fluidic
KW  - lenslet array
KW  - LED chip
KW  - image sensor
KW  - biosensor
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1456
ER  - 
TY  - CHAP
A1  - Kreutz, Christian
A1  - Lörgen, Jürgen
A1  - Graewe, Boris
A1  - Bargon, Joachim
A1  - Yoshida, Mayumi
A1  - Freso, Zachary M.
A1  - Frèchet, Jean M. J.
T1  - High frequency quartz micro balances: a promising path to enhanced sensitivity of gravimetric sensors
N2  - An array of 50 MHz quartz microbalances (QMBs) coated with a dendronized polymer was used to detect small amounts of volatile organic compounds (VOCs) in the gas phase. The results were compared to those obtained with the commonly used 10 MHz QMBs. The 50 MHz QMBs proved to be a powerful tool for the detection of VOCs in the gas phase; therefore, they represent a promising alternative to the much more delicate surface acoustic wave devices (SAWs).
KW  - Biosensor
KW  - Quartz micro balances
KW  - electronic noses dendronized polymers inverted mesa technology
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1445
ER  - 
TY  - CHAP
A1  - Mirmohseni, Abdolreza
A1  - Rostamizadeh, Kobra
T1  - Quartz crystal nanobalance in conjunction with principal component analysis for  identification of volatile organic compounds
N2  - Quartz crystal nanobalance (QCN) sensors are considered as powerful masssensitive sensors to determine materials in the sub-nanogram level. In this study, a single piezoelectric quartz crystal nanobalance modified with polystyrene was employed to detect benzene, toluene, ethylbenzene and xylene (BTEX compounds). The frequency shift of the QCN sensor was found to be linear against the BTEX compound concentrations in the range about 1-45 mg l-1. The correlation coefficients for benzene, toluene, ethylbenzene, and xylene were 0.991, 0.9977, 0.9946 and 0.9971, respectively. The principal component analysis was also utilized to process the frequency response data of the single piezoelectric crystal at different times, considering to the different adsorption-desorption dynamics of BTEX compounds. Using principal component analysis, it was found that over 90% of the data variance could still be explained by use of two principal components (PC1 and PC2). Subsequently, the successful identification of benzene and toluene was possible through the principal component analysis of the transient responses of the polystyrene modified QCN sensor. The results showed that the polystyrene-modified QCN had favorable identification and quantification performances for the BTEX compounds.
KW  - Biosensor
KW  - Quartz crystal nanobalance (QCN)
KW  - BTEX compounds
KW  - principal component
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1434
ER  - 
TY  - CHAP
A1  - Wagner, Thorsten
A1  - Kohl, Claus-Dieter
A1  - Fröba, Michael
A1  - Tiemann, Michael
T1  - Gas sensing properties of ordered mesoporous SnO2
N2  - We report on the synthesis and CO gas-sensing properties of mesoporous tin(IV) oxides (SnO2). For the synthesis cetyltrimethylammonium bromide (CTABr) was used as a structure-directing agent; the resulting SnO2 powders were applied as films to commercially available sensor substrates by drop coating. Nitrogen physisorption shows specific surface areas up to 160 m2·g-1 and mean pore diameters of about 4 nm, as verified by TEM. The film conductance was measured in dependence on the CO concentration in humid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivity at low CO concentrations and turn out to be largely insensitive towards changes in the relative humidity. We compare the materials with commercially available SnO2-based sensors.
KW  - Biosensor
KW  - Tin oxide
KW  - sensing properties
KW  - CO
KW  - humidity
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1422
ER  - 
TY  - CHAP
A1  - Näther, Niko
A1  - Juárez, Leon M.
A1  - Emmerich, Rüdiger
A1  - Berger, Jörg
A1  - Friedrich, Peter
A1  - Schöning, Michael Josef
T1  - Detection of hydrogen peroxide (H2O2) at exposed temperatures for industrial processes
N2  - An H2O2 sensor for the application in industrial sterilisation processes has been developed. Therefore, automated sterilisation equipment at laboratory scale has been constructed using parts from industrial sterilisation facilities. In addition, a software tool has been developed for the control of the sterilisation equipment at laboratory scale. First measurements with the developed sensor set-up as part of the sterilisation equipment have been performed and the sensor has been physically characterised by optical microscopy and SEM.
KW  - Biosensor
KW  - Gas sensor
KW  - hydrogen peroxide
KW  - sterilisation
KW  - catalytic decomposition
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1418
ER  - 
TY  - CHAP
A1  - Koplin, Tobias J.
A1  - Siemons, Maike
A1  - Océn-Valéntin, César
A1  - Sanders, Daniel
A1  - Simon, Ulrich
T1  - Workflow for high throughput screening of gas sensing materials
N2  - The workflow of a high throughput screening setup for the rapid identification of new and improved sensor materials is presented. The polyol method was applied to prepare nanoparticular metal oxides as base materials, which were functionalised by surface doping. Using multi-electrode substrates and high throughput impedance spectroscopy (HT-IS) a wide range of materials could be screened in a short time. Applying HT-IS in search of new selective gas sensing materials a NO2-tolerant NO sensing material with reduced sensitivities towards other test gases was identified based on iridium doped zinc oxide. Analogous behaviour was observed for iridium doped indium oxide.
KW  - Biosensor
KW  - High throughput experimentation
KW  - gas sensor
KW  - metal oxide
KW  - doping
KW  - impedance spectroscopy
KW  - nitrogen oxides
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1407
ER  - 
TY  - CHAP
A1  - Sakthivel, Mariappan
A1  - Weppner, Werner
T1  - Response behaviour of a hydrogen sensor based on ionic conducting polymer-metal interfaces prepared by the chemical reduction method
N2  - A solid-state amperometric hydrogen sensor based on a protonated Nafion membrane and catalytic active electrode operating at room temperature was fabricated and tested. Ionic conducting polymer-metal electrode interfaces were prepared chemically by using the impregnation-reduction method. The polymer membrane was impregnated with tetra-ammine platinum chloride hydrate and the metal ions were subsequently reduced by using either sodium tetrahydroborate or potassium tetrahydroborate. The hydrogen sensing characteristics with air as reference gas is reported. The sensors were capable of detecting hydrogen concentrations from 10 ppm to 10% in nitrogen. The response time was in the range of 10-30 s and a stable linear current output was observed. The thin Pt films were characterized by XRD, Infrared Spectroscopy, Optical Microscopy, Atomic Force Microscopy, Scanning Electron Microscopy and EDAX.
KW  - Biosensor
KW  - Hydrogen sensor
KW  - amperometric sensor
KW  - porous Pt electrode
KW  - chemical reduction method
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1399
ER  - 
TY  - CHAP
A1  - Chaiyboun, Ali
A1  - Traute, Rüdiger
A1  - Kiesewetter, Olaf
A1  - Ahlers, Simon
A1  - Müller, Gerhard
A1  - Doll, Theodor
T1  - Modular analytical multicomponent analysis in gas sensor arrays
N2  - A multi-sensor system is a chemical sensor system which quantitatively and qualitatively records gases with a combination of cross-sensitive gas sensor arrays and pattern recognition software. This paper addresses the issue of data analysis for identification of gases in a gas sensor array. We introduce a software tool for gas sensor array configuration and simulation. It concerns thereby about a modular software package for the acquisition of data of different sensors. A signal evaluation algorithm referred to as matrix method was used specifically for the software tool. This matrix method computes the gas concentrations from the signals of a sensor array. The software tool was used for the simulation of an array of five sensors to determine gas concentration of CH4, NH3, H2, CO and C2H5OH. The results of the present simulated sensor array indicate that the software tool is capable of the following: (a) identify a gas independently of its concentration; (b) estimate the concentration of the gas, even if the system was not previously exposed to this concentration; (c) tell when a gas concentration exceeds a certain value. A gas sensor data base was build for the configuration of the software. With the data base one can create, generate and manage scenarios and source files for the simulation. With the gas sensor data base and the simulation software an on-line Web-based version was developed, with which the user can configure and simulate sensor arrays on-line.
KW  - Biosensor
KW  - Main sensitivity
KW  - cross sensitivity
KW  - matrix method
KW  - gas sensor array
KW  - modelling
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1358
ER  - 
TY  - CHAP
A1  - Srivastava, Alok
A1  - Singh, Virendra
A1  - Dhand, Chetna
A1  - Kaur, Manindar
A1  - Singh, Tejvir
A1  - Witte, Katrin
A1  - Scherer, Ulrich W.
T1  - Study of swift heavy ion modified conduction polymer composites for application as gas sensor
N2  - A polyaniline-based conducting composite was prepared by oxidative polymerisation of aniline in a polyvinylchloride (PVC) matrix. The coherent free standing thin films of the composite were prepared by a solution casting method. The polyvinyl chloride-polyaniline composites exposed to 120 MeV ions of silicon with total ion fluence ranging from 1011 to 1013 ions/cm2, were observed to be more sensitive towards ammonia gas than the unirradiated composite. The response time of the irradiated composites was observed to be comparably shorter. We report for the first time the application of swift heavy ion modified insulating polymer conducting polymer (IPCP) composites for sensing of ammonia gas.
KW  - Biosensor
KW  - Conducing polymer
KW  - ammonia gas sensors
KW  - swift heavy ions
KW  - polymer composites
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1345
ER  - 
TY  - CHAP
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
T1  - Preface of the Special Issue of I3S 2005 in Jülich (Germany)
N2  - International Symposium on Sensor Science, I3S 2005 <3; 2005; Juelich, Germany> In: Sensors 2006, 6, 260-261 ISSN 1424-8220
KW  - Biosensor
KW  - I3S 2005
KW  - International Symposium on Sensor Science
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1365
ER  - 
TY  - CHAP
A1  - Poghossian, Arshak
A1  - Schumacher, Kerstin
A1  - Kloock, Joachim P.
A1  - Rosenkranz, Christian
A1  - Schultze, Joachim W.
A1  - Müller-Veggian, Mattea
A1  - Schöning, Michael Josef
T1  - Functional testing and characterisation of ISFETs on wafer level by means of a micro-droplet cell
N2  - A wafer-level functionality testing and characterisation system for ISFETs (ionsensitive field-effect transistor) is realised by means of integration of a specifically designed capillary electrochemical micro-droplet cell into a commercial wafer prober-station. The developed system allows the identification and selection of “good” ISFETs at the earliest stage and to avoid expensive bonding, encapsulation and packaging processes for nonfunctioning ISFETs and thus, to decrease costs, which are wasted for bad dies. The developed system is also feasible for wafer-level characterisation of ISFETs in terms of sensitivity, hysteresis and response time. Additionally, the system might be also utilised for wafer-level testing of further electrochemical sensors.
KW  - Biosensor
KW  - Biosensorik
KW  - ISFET
KW  - Wafer
KW  - ISFET
KW  - wafer-level testing
KW  - capillary micro-droplet cell
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1259
ER  - 
TY  - JOUR
A1  - Baroud, G.
A1  - Wu, J.Z.
A1  - Bohner, M
A1  - Sponagel, Stefan
A1  - Steffen, T.
T1  - How to determine the permeability for cement infiltration into osteoporotic cancellous bone
JF  - Medical Engineering & Physics. 25 (2003), H. 4
N2  - Cement augmentation is an emerging surgical procedure in which bone cement is used to infiltrate and reinforce osteoporotic vertebrae. Although this infiltration procedure has been widely applied, it is performed empirically and little is known about the flow characteristics of cement during the injection process. We present a theoretical and experimental approach to investigate the intertrabecular bone permeability during the infiltration procedure. The cement permeability was considered to be dependent on time, bone porosity, and cement viscosity in our analysis. In order to determine the time-dependent permeability, ten cancellous bone cores were harvested from osteoporotic vertebrae, infiltrated with acrylic cement at a constant flow rate, and the pressure drop across the cores during the infiltration was measured. The viscosity dependence of the permeability was determined based on published experimental data. The theoretical model for the permeability as a function of bone porosity and time was then fit to the testing data. Our findings suggest that the intertrabecular bone permeability depends strongly on time. For instance, the initial permeability (60.89 mm4/N.s) reduced to approximately 63% of its original value within 18 seconds. This study is the first to analyze cement flow through osteoporotic bone. The theoretical and experimental models provided in this paper are generic. Thus, they can be used to systematically study and optimize the infiltration process for clinical practice.
KW  - Osteoporose
KW  - Permeabilität
KW  - Viskose Strömung
KW  - Viskosität
KW  - Vertebroplastie
KW  - Cement infiltration
KW  - Vertebroplasty
KW  - Osteoporosis
KW  - Permeability
KW  - Experiment
KW  - Analysis
KW  - Viscous flow
Y1  - 2003
SN  - 1350-4533
SP  - 283
EP  - 288
ER  - 
TY  - JOUR
A1  - Kühn, Raoul-Roman
A1  - Haugner, Werner
A1  - Staat, Manfred
A1  - Sponagel, Stefan
T1  - A Two Phase Mixture Model based on Bone Observation
N2  - An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff’s law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency.
KW  - Knochen
KW  - Knochenbildung
KW  - Knochenchirugie
KW  - Strukturanalyse
KW  - Schwammknochen
KW  - Knochendichte
KW  - Wolffsches Gesetz
KW  - bone structure
KW  - bone density
KW  - Wolff's Law
KW  - cancellous bone
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Vu, Duc-Khoi
A1  - Staat, Manfred
T1  - An algorithm for shakedown analysis of structure with temperature dependent yield stress
N2  - This work is an attempt to answer the question: How to use convex programming in shakedown analysis of structures made of materials with temperature-dependent properties. Based on recently established shakedown theorems and formulations, a dual relationship between upper and lower bounds of the shakedown limit load is found, an algorithmfor shakedown analysis is proposed. While the original problem is neither convex nor concave, the algorithm presented here has the advantage of employing convex programming tools.
KW  - Einspielen <Werkstoff>
KW  - Temperaturabhängigkeit
KW  - Fließgrenze
KW  - Shakedown
KW  - shakedown analysis
KW  - yield stress
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Direct FEM Limit and Shakedown Analysis with Uncertain Data
N2  - The structural reliability with respect to plastic collapse or to inadaptation is formulated on the basis of the lower bound limit and shakedown theorems. A direct definition of the limit state function is achieved which permits the use of the highly effective first order reliability methods (FORM) is achieved. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis. The limit state function and its gradient are obtained from a mathematical optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error, leading to highly effective and precise reliability analyses.
KW  - Finite-Elemente-Methode
KW  - Einspielen <Werkstoff>
KW  - FEM
KW  - Einspielanalyse
KW  - shakedown
KW  - limit load
KW  - reliability analysis
KW  - FEM
KW  - direct method
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - LISA - a European project for FEM-based limit and shakedown analysis
N2  - The load-carrying capacity or the safety against plastic limit states are the central questions in the design of structures and passive components in the apparatus engineering. A precise answer is most simply given by limit and shakedown analysis. These methods can be based on static and kinematic theorems for lower and upper bound analysis. Both may be formulated as optimization problems for finite element discretizations of structures. The problems of large-scale analysis and the extension towards realistic material modelling will be solved in a European research project. Limit and shakedown analyses are briefly demonstrated with illustrative examples.
KW  - Einspielen <Werkstoff>
KW  - Traglast
KW  - Finite-Elemente-Methode
KW  - Traglastanalyse
KW  - Einspielanalyse
KW  - FEM
KW  - limit analysis
KW  - shakedown analysis
Y1  - 2001
ER  - 
TY  - CHAP
A1  - Staat, Manfred
T1  - Design by Analysis of Pressure Components by non-linear Optimization
N2  - This paper presents the direct route to Design by Analysis (DBA) of the new European pressure vessel standard in the language of limit and shakedown analysis (LISA). This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for some examples from the DBA-Manual. One observation from the examples is, that the optimisation approach gives reliable and close lower bound solutions leading to simple and optimised design decision.
KW  - Analytischer Zulaessigkeitsnachweis
KW  - FEM
KW  - Einspiel-Analyse
KW  - design-by-analysis
KW  - finite element analysis
KW  - limit and shakedown analysis
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Basis Reduction for the Shakedown Problem for Bounded Kinematic Hardening Material
N2  - Limit and shakedown analysis are effective methods for assessing the load carrying capacity of a given structure. The elasto–plastic behavior of the structure subjected to loads varying in a given load domain is characterized by the shakedown load factor, defined as the maximum factor which satisfies the sufficient conditions stated in the corresponding static shakedown theorem. The finite element dicretization of the problem may lead to very large convex optimization. For the effective solution a basis reduction method has been developed that makes use of the special problem structure for perfectly plastic material. The paper proposes a modified basis reduction method for direct application to the two-surface plasticity model of bounded kinematic hardening material. The considered numerical examples show an enlargement of the load carrying capacity due to bounded hardening.
KW  - Finite-Elemente-Methode
KW  - Einspielen <Werkstoff>
KW  - Basis Reduktion
KW  - konvexe Optimierung
KW  - FEM
KW  - Druckgeräte
KW  - Basis reduction
KW  - Convex optimization
KW  - FEM
KW  - Shakedown analysis
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Shakedown and ratchetting under tension-torsion loadings: analysis and experiments
N2  - Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis.
KW  - Einspielen <Werkstoff>
KW  - Einspielen
KW  - Ratchetting
KW  - Zug-Druck Belastung
KW  - shakedown
KW  - ratchetting
KW  - tension–torsion loading
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Direct finite element route for design-by-analysis of pressure components
N2  - In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion.
KW  - Einspielen <Werkstoff>
KW  - Plastizität
KW  - Deformation
KW  - Analytischer Zulaessigkeitsnachweis
KW  - Einspiel-Analyse
KW  - fortschreitende plastische Deformation
KW  - alternierend Verformbarkeit
KW  - Einspiel-Kriterium
KW  - Design-by-analysis
KW  - Shakedown analysis
KW  - Progressive plastic deformation
KW  - Alternating plasticity
KW  - Shakedown criterion
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Local and global collapse pressure of longitudinally flawed pipes and cylindrical vessels
N2  - Limit loads can be calculated with the finite element method (FEM) for any component, defect geometry, and loading. FEM suggests that published long crack limit formulae for axial defects under-estimate the burst pressure for internal surface defects in thick pipes while limit loads are not conservative for deep cracks and for pressure loaded crack-faces. Very deep cracks have a residual strength, which is modelled by a global collapse load. These observations are combined to derive new analytical local and global collapse loads. The global collapse loads are close to FEM limit analyses for all crack dimensions.
KW  - Finite-Elemente-Methode
KW  - Grenzwertberechnung
KW  - Axialbelastung
KW  - FEM
KW  - Grenzwertberechnung
KW  - Axialbelastung
KW  - Traglastanalyse
KW  - Limit analysis
KW  - Global and local collapse
KW  - Axially cracked pipe
KW  - Pressure loaded crack-face
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Cyclic plastic deformation tests to verify FEM-based shakedown analyses
N2  - Fatigue analyses are conducted with the aim of verifying that thermal ratcheting is limited. To this end it is important to make a clear distintion between the shakedown range and the ratcheting range (continuing deformation). As part of an EU-supported research project, experiments were carried out using a 4-bar model. The experiment comprised a water-cooled internal tube, and three insulated heatable outer test bars. The system was subjected to alternating axial forces, superimposed with alternating temperatures at the outer bars. The test parameters were partly selected on the basis of previous shakedown analyses. During the test, temperatures and strains were measured as a function of time. The loads and the resulting stresses were confirmed on an ongoing basis during performance of the test, and after it. Different material models were applied for this incremental elasto-plastic analysis using the ANSYS program. The results of the simulation are used to verify the FEM-based shakedown analysis.
KW  - Materialermüdung
KW  - Einspielen <Werkstoff>
KW  - Materialermüdung
KW  - shakedown analyses
KW  - thermal ratcheting
KW  - fatigue analyses
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Plastic collapse analysis of longitudinally flawed pipes and vessels
N2  - Improved collapse loads of thick-walled, crack containing pipes and vessels are suggested. Very deep cracks have a residual strength which is better modelled by a global limit load. In all burst tests, the ductility of pressure vessel steels was sufficiently high whereby the burst pressure could be predicted by limit analysis with no need to apply fracture mechanics. The relative prognosis error increases however, for long and deep defects due to uncertainties of geometry and strength data.
KW  - Druckbehälter
KW  - Stahl
KW  - Druckbelastung
KW  - Druckbeanspruchung
KW  - Rohr
KW  - Rohrbruch
KW  - Druckbehälter
KW  - Stahl
KW  - Druckbelastung
KW  - Druckbeanspruchung
KW  - Rohrbruch
KW  - Fehlerstellen
KW  - pipes
KW  - vessels
KW  - load limit
KW  - burst tests
KW  - burst pressure
KW  - flaw
Y1  - 2004
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
T1  - Direct static FEM approach to limit and shakedown analysis
N2  - Safety and reliability of structures may be assessed indirectly by stress distributions. Limit and shakedown theorems are simplified but exact methods of plasticity that provide safety factors directly in the loading space. These theorems may be used for a direct definition of the limit state function for failure by plastic collapse or by inadaptation. In a FEM formulation the limit state function is obtained from a nonlinear optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error. Moreover, the direct way leads to highly effective and precise reliability analyses. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis.
KW  - Einspielen <Werkstoff>
KW  - Nichtlineare Optimierung
KW  - Shakedown
KW  - Shakedown
KW  - limit load
KW  - lower bound theorem
KW  - nonlinear optimization
KW  - reliability
Y1  - 2000
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
T1  - The restricted influence of kinematic hardening on shakedown loads
N2  - Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown analysis are comparatively simple. It is shown that shakedown analysis can make quite stable predictions of admissible load ranges despite the simplicity of the underlying hardening models. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. Both give identical or similar shakedown ranges. Structural shakedown analyses show that the loading may have a more pronounced effect than the hardening model.
KW  - Biomedizinische Technik
KW  - Einspielen <Werkstoff>
KW  - Shakedown
KW  - Ratcheting
KW  - Bruchmechanik
KW  - shakedown
KW  - material shakedown
KW  - linear kinematic hardening
KW  - nonlinear kinematic hardening
KW  - ratchetting
Y1  - 2002
ER  -