On the nonlinear characterization of the long term behavior of polymeric materials

1987 ◽  
Vol 27 (2) ◽  
pp. 144-148 ◽  
Author(s):  
O. S. Brueller
Keyword(s):  
Polymeric Materials ◽  
Nonlinear Characterization ◽  
Long Term Behavior

scholarly journals (M,β)-Stability of Positive Linear Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Octavian Pastravanu ◽  
Mihaela-Hanako Matcovschi
Keyword(s):  
Linear System ◽  
Linear Systems ◽  
Transient Behavior ◽  
Short Term ◽  
Time Dynamics ◽  
The Right ◽  
Long Term Behavior ◽  
Stability Concept

The main purpose of this work is to show that the Perron-Frobenius eigenstructure of a positive linear system is involved not only in the characterization of long-term behavior (for which well-known results are available) but also in the characterization of short-term or transient behavior. We address the analysis of the short-term behavior by the help of the “(M,β)-stability” concept introduced in literature for general classes of dynamics. Our paper exploits this concept relative to Hölder vectorp-norms,1≤p≤∞, adequately weighted by scaling operators, focusing on positive linear systems. Given an asymptotically stable positive linear system, for each1≤p≤∞, we prove the existence of a scaling operator (built from the right and left Perron-Frobenius eigenvectors, with concrete expressions depending onp) that ensures the best possible values for the parametersMandβ, corresponding to an “ideal” short-term (transient) behavior. We provide results that cover both discrete- and continuous-time dynamics. Our analysis also captures the differences between the cases where the system dynamics is defined by matrices irreducible and reducible, respectively. The theoretical developments are applied to the practical study of the short-term behavior for two positive linear systems already discussed in literature by other authors.

scholarly journals Characterization of Water Conducting Fracture and their Long-term Behavior in Deep Crystalline Rock :

2014 ◽  
Vol 55 (4) ◽  
pp. 156-165 ◽  
Author(s):  
Masayuki ISHIBASHI ◽  
Tomomi ANDO ◽  
Eiji SASAO ◽  
Takashi YUGUCHI ◽  
Shoji NISHIMOTO ◽  
...  
Keyword(s):  
Crystalline Rock ◽  
Long Term Behavior

scholarly journals Can Accelerated Aging Procedures Predict the Long Term Behavior of Polymers Exposed to Different Environments?

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2688
Author(s):  
Mariaenrica Frigione ◽  
Alvaro Rodríguez-Prieto
Keyword(s):  
Environmental Conditions ◽  
Accelerated Aging ◽  
Environmental Parameters ◽  
Polymeric Materials ◽  
Vapor Condensation ◽  
Natural Exposure ◽  
Long Term Performance ◽  
Term Performance ◽  
Long Term Behavior

During their useful life, polymers are subject to degradation processes due to exposure to specific environmental conditions over long times. These processes generally lead to changes, almost always irreversible, of properties and performances of polymers, changes which would be useful to be able to predict in advance. To meet this need, numerous investigations have been focused on the possibility to predict the long-term performance of polymers, if exposed to specific environments, by the so called “accelerated aging” tests. In such procedures, the long-term behavior of polymeric materials is typically predicted by subjecting them to cycles of radiations, temperatures, vapor condensation, and other external agents, at levels well above those found in true conditions in order to accelerate the degradation of polymers: this can produce effects that substantially deviate from those observable under natural exposure. Even following the standard codes, different environmental parameters are often used in the diverse studies, making it difficult to compare different investigations. The correlation of results from accelerated procedures with data collected after natural exposure is still a debated matter. Furthermore, since the environmental conditions are a function of the season and the geographical position, and are also characteristic of the type of exposure area, the environmental parameters to be used in accelerated aging tests should also consider these variables. These and other issues concerning accelerated aging tests applied to polymers are analyzed in the present work. However, bearing in mind the limitations of these practices, they can find useful applications for rating the durability of polymeric materials.

scholarly journals Application of a Novel Measurement Setup for Characterization of Graphene Microelectrodes and a Comparative Study of Variables Influencing Charge Injection Limits of Implantable Microelectrodes

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2725 ◽  
Author(s):  
Ana Cisnal ◽  
Frank R. R. Ihmig ◽  
Juan-Carlos Fraile ◽  
Javier Pérez-Turiel ◽  
Víctor Muñoz-Martinez
Keyword(s):  
Biomedical Applications ◽  
Charge Injection ◽  
Electrochemical Characteristics ◽  
Maximum Charge ◽  
Fraunhofer Institute ◽  
Long Term Behavior ◽  
Electrochemical Evaluation

Depending on their use, electrodes must have a certain size and design so as not to compromise their electrical characteristics. It is fundamental to be aware of all dependences on external factors that vary the electrochemical characteristics of the electrodes. When using implantable electrodes, the maximum charge injection capacity (CIC) is the total amount of charge that can be injected into the tissue in a reversible way. It is fundamental to know the relations between the characteristics of the microelectrode itself and its maximum CIC in order to develop microelectrodes that will be used in biomedical applications. CIC is a very complex measure that depends on many factors: material, size (geometric and effectiveness area), and shape of the implantable microelectrode and long-term behavior, composition, and temperature of the electrolyte. In this paper, our previously proposed measurement setup and automated calculation method are used to characterize a graphene microelectrode and to measure the behavior of a set of microelectrodes that have been developed in the Fraunhofer Institute for Biomedical Engineering (IBMT) labs. We provide an electrochemical evaluation of CIC for these microelectrodes by examining the role of the following variables: pulse width of the stimulation signal, electrode geometry and size, roughness factor, solution, and long-term behavior. We hope the results presented in this paper will be useful for future studies and for the manufacture of advanced implantable microelectrodes.

Morphology and Long Term Behavior of Polymer Cement Concrete

1989 ◽  
Vol 179 ◽  
Author(s):  
K. P. Grosskurth
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymeric Materials ◽  
Heterogeneous Material ◽  
Cement Concrete ◽  
Temperature Dependent ◽  
Dependent Behavior ◽  
Long Term Behavior

AbstractPolymer-modified cement concrete represents a heterogeneous material whose properties are influenced more by the properties of the polymers than by the properties of the cement component. Typical of polymeric materials are their temperature dependent behavior. This temperature dependence can be related to the glass transition temperature of the polymer. In cases where the temperature is higher than the glass transition temperature, strength decreases while deformability simultaneously increases. Polymeric films are formed in the dispersed polymer systems as a result of reactions occurring at the glass transition temperature. A styrene/acrylic modified concrete was studied at different polymer loadings. The tensile and compressive strengths of this system were studied as a function of temperature. Increasing deformability temperatures principally at higher polymer loadings near the glass transition temperature and decreasing strength occurred.

Long-term behavior and statistical characterization of BeiDou signal-in-space errors

GPS Solutions ◽  
2017 ◽  
Vol 21 (4) ◽  
pp. 1907-1922 ◽  
Author(s):  
Yun Wu ◽  
Xiaolei Liu ◽  
Wanke Liu ◽  
Jie Ren ◽  
Yidong Lou ◽  
...  
Keyword(s):  
Statistical Characterization ◽  
Long Term Behavior

French High Level Nuclear Waste Program — Key Research Areas

1985 ◽  
Vol 50 ◽  
Author(s):  
Claude G. Sombret
Keyword(s):  
Nuclear Waste ◽  
Research Program ◽  
Industrial Processes ◽  
Research Areas ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Long Term Behavior ◽  
Scientific Fields

AbstractThe most important aspects of this research program concern disposal safety: the long-term behavior and sensitivity of the materials to the variability inherent in industrial processes, and the characterization of the final product. This research required different investigations involving various scientific fields, and implements radioactive and non-radioactive glass samples as well as industrial scale glass blocks. Certain studies have now been completed; others are still in progress.

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