{"title":"Does the nonuniqueness of the discrete relaxation spectrum really matter?","authors":"Sachin Shanbhag","doi":"10.1007/s00397-025-01485-z","DOIUrl":null,"url":null,"abstract":"<div><p>Unlike the continuous relaxation spectrum (CRS), discrete relaxation spectra (DRS) are nonunique. This means that the linear viscoelastic response of a material can be described by two or more distinct DRS. Constraints like parsimony and consistency help us to infer meaningful DRS, but are not sufficient to induce uniqueness as it is an inherent property of discretization. Using parsimonious DRS from two different programs (DISCRETE and pyReSpect) on data drawn from experiments, simulations, and theory, we demonstrate that nonuniqueness does not hinder the two most common applications of relaxation spectra, viz. characterization and interconversion. Furthermore, information for reconstructing the CRS underlying the data is embedded in the DRS. Therefore, for most practical considerations, we find that the nonuniqueness of the DRS does not matter.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"64 2-3","pages":"107 - 116"},"PeriodicalIF":2.3000,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Rheologica Acta","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s00397-025-01485-z","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MECHANICS","Score":null,"Total":0}
引用次数: 0
Abstract
Unlike the continuous relaxation spectrum (CRS), discrete relaxation spectra (DRS) are nonunique. This means that the linear viscoelastic response of a material can be described by two or more distinct DRS. Constraints like parsimony and consistency help us to infer meaningful DRS, but are not sufficient to induce uniqueness as it is an inherent property of discretization. Using parsimonious DRS from two different programs (DISCRETE and pyReSpect) on data drawn from experiments, simulations, and theory, we demonstrate that nonuniqueness does not hinder the two most common applications of relaxation spectra, viz. characterization and interconversion. Furthermore, information for reconstructing the CRS underlying the data is embedded in the DRS. Therefore, for most practical considerations, we find that the nonuniqueness of the DRS does not matter.
期刊介绍:
"Rheologica Acta is the official journal of The European Society of Rheology. The aim of the journal is to advance the science of rheology, by publishing high quality peer reviewed articles, invited reviews and peer reviewed short communications.
The Scope of Rheologica Acta includes:
- Advances in rheometrical and rheo-physical techniques, rheo-optics, microrheology
- Rheology of soft matter systems, including polymer melts and solutions, colloidal dispersions, cement, ceramics, glasses, gels, emulsions, surfactant systems, liquid crystals, biomaterials and food.
- Rheology of Solids, chemo-rheology
- Electro and magnetorheology
- Theory of rheology
- Non-Newtonian fluid mechanics, complex fluids in microfluidic devices and flow instabilities
- Interfacial rheology
Rheologica Acta aims to publish papers which represent a substantial advance in the field, mere data reports or incremental work will not be considered. Priority will be given to papers that are methodological in nature and are beneficial to a wide range of material classes. It should also be noted that the list of topics given above is meant to be representative, not exhaustive. The editors welcome feedback on the journal and suggestions for reviews and comments."