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  1. Article ; Online: Stress overshoot, hysteresis, and the Bauschinger effect in sheared dense colloidal suspensions.

    Kushnir, Dmytro / Ruscher, Céline / Bartsch, Eckhard / Thalmann, Fabrice / Hébraud, Pascal

    Physical review. E

    2022  Volume 106, Issue 3-1, Page(s) 34611

    Abstract: The mechanical nonlinear response of dense Brownian suspensions of polymer gel particles is studied experimentally and by means of numerical simulations. It is shown that the response to the application of a constant shear rate depends on the previous ... ...

    Abstract The mechanical nonlinear response of dense Brownian suspensions of polymer gel particles is studied experimentally and by means of numerical simulations. It is shown that the response to the application of a constant shear rate depends on the previous history of the suspension. When the flow starts from a suspension at rest, it exhibits an elastic response followed by a stress overshoot and then a plastic flow regime. Conversely, after flow reversal, the stress overshoot does not occur, and the apparent elastic modulus is reduced while numerical simulations reveal that the anisotropy of the local microstructure is delayed relative to the macroscopic stress.
    Language English
    Publishing date 2022-10-20
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2844562-4
    ISSN 2470-0053 ; 2470-0045
    ISSN (online) 2470-0053
    ISSN 2470-0045
    DOI 10.1103/PhysRevE.106.034611
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online: Stress overshoot, hysteresis and Bauschinger effect in sheared dense colloidal suspensions

    Kushnir, Dmytro / Ruscher, Céline / Bartsch, Eckhard / Thalmann, Fabrice / Hébraud, Pascal

    2022  

    Abstract: The mechanical non-linear response of dense Brownian suspensions of polymer gel particles is studied experimentally and by means of numerical simulations. It is shown that the response to the application of a constant shear rate depends on the previous ... ...

    Abstract The mechanical non-linear response of dense Brownian suspensions of polymer gel particles is studied experimentally and by means of numerical simulations. It is shown that the response to the application of a constant shear rate depends on the previous history of the suspension. When the flow starts from a suspension at rest, it exhibits an elastic response followed by a stress overshoot and then a plastic flow regime. Conversely, after flow reversal, the stress overshoot does not occur, and the apparent elastic modulus is reduced while numerical simulations reveal that the anisotropy of the local microstructure is delayed relative to the macroscopic stress.

    Comment: Submitted
    Keywords Condensed Matter - Soft Condensed Matter ; Condensed Matter - Materials Science
    Publishing date 2022-02-23
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

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  3. Book ; Thesis: Untersuchung der Lagegenauigkeit von Dreieckspunkten im Südosten Hessens

    Bartsch, Eckhard

    (Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften : R. C ; H. 145)

    1970  

    Author's details vorgelegt von Eckhard Bartsch
    Series title Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften : R. C ; H. 145
    Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften
    Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften ; R. C
    Collection Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften
    Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften ; R. C
    Size 51 S.
    Publishing place München
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Zugl. Diss. d. Fak. f. Bauingenieurwesen d. TH Darmstadt
    Note [Maschinenschr. vervielf.]
    Accompanying material Anl. ; 4-o
    HBZ-ID HT007872486
    Database Catalogue ZB MED Nutrition, Environment, Agriculture

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    In stock of ZB MED Bonn / Germany

    Shelf markLoan statusLocation
    4' II b, 18196 (145) order for loan Geschlossenes Magazin (U2)

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  4. Article ; Online: New insights into re-entrant melting of microgel particles by polymer-induced aggregation experiments.

    Schneider, Jochen / Werner, Marcel / Bartsch, Eckhard

    Soft matter

    2018  Volume 14, Issue 19, Page(s) 3811–3817

    Abstract: While microgels are in general described as soft particles, polystyrene (PS) microgels can be synthesized in a way that cross-link density has only a minor influence on their physical properties. Even though the particles swell in a good solvent, the ... ...

    Abstract While microgels are in general described as soft particles, polystyrene (PS) microgels can be synthesized in a way that cross-link density has only a minor influence on their physical properties. Even though the particles swell in a good solvent, the imparted slight softness still allows a mapping on hard sphere behaviour for a large range of cross-link densities [Schneider et al., Soft Matter, 2017, 13, 445]. Nevertheless, the hard sphere analogy breaks down as soon as polymer chains are added to these systems. Quantitative differences between PS microgels and true hard sphere systems appear and the differences between stronger and weaker cross-linked PS microgels can be observed. To gain deeper insights into the origin of these deviations from true hard sphere behaviour, this work is addressed to a systematic study of the colloid-polymer interactions in PS microgel-polymer mixtures. We investigated the aggregation behaviour (namely aggregation concentration and cluster structure) as a function of colloid size, cross-link density and colloid-polymer size ratio in very dilute colloidal suspensions. Our results show that the interplay of cross-link density and polymer size is a key parameter for the strength of the colloid-polymer interactions. Furthermore, the centre-to-centre distance of the colloidal particles in the formed clusters decreases if the cross-link density is decreased, allowing for a higher packing density. This may also explain the unusually high fluid packing fractions observed in the re-entry region of the phase diagram of PS microgel-free PS polymer mixtures.
    Language English
    Publishing date 2018-05-16
    Publishing country England
    Document type Journal Article
    ZDB-ID 2191476-X
    ISSN 1744-6848 ; 1744-683X
    ISSN (online) 1744-6848
    ISSN 1744-683X
    DOI 10.1039/c7sm01922j
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: On tuning microgel character and softness of cross-linked polystyrene particles.

    Schneider, Jochen / Wiemann, Malte / Rabe, Anna / Bartsch, Eckhard

    Soft matter

    2017  Volume 13, Issue 2, Page(s) 445–457

    Abstract: Polystyrene (PS) microgel colloids have often been used successfully to model hard sphere behaviour even though the term "gel" invokes inevitably the notion of a more or less soft, deformable object. Here we systematically study the effect of reducing ... ...

    Abstract Polystyrene (PS) microgel colloids have often been used successfully to model hard sphere behaviour even though the term "gel" invokes inevitably the notion of a more or less soft, deformable object. Here we systematically study the effect of reducing the cross-link density from 1 : 10 (1 cross-link per 10 monomers) to 1 : 100 on particle interactions and "softness". We report on the synthesis and purification of 1 : 10, 1 : 25, 1 : 50, 1 : 75 and 1 : 100 cross-linked PS particles and their characterization in terms of single particle properties, as well as the behaviour of concentrated dispersions. We are able to tune particle softness in the range between soft PNiPAM-microgels and hard PMMA particles while still allowing the mapping of the microgels onto hard sphere behavior with respect to phase diagram and static structure factors. This is mainly due to a rather homogeneous radial distribution of cross-links in contrast to PNiPAM microgels where the cross-link density decreases radially. We find that up to a cross-link density of 1 : 50 particle form factors are perfectly described by a homogeneous sphere model whereas 1 : 75 and 1 : 100 cross-linked spheres are slightly better described as fuzzy spheres. However the fuzziness is rather small compared to typical PNiPAM microgels so that a hard sphere mapping still holds even for these low cross-link densities. Finally, by varying the reaction conditions - changing from batch to semibatch emulsion polymerization and varying the feed rate or by adjusting the monomer to initiator ratio we can tune the fuzziness or significantly alter the inner structure to a more open, star-like architecture.
    Language English
    Publishing date 2017-01-04
    Publishing country England
    Document type Journal Article
    ZDB-ID 2191476-X
    ISSN 1744-6848 ; 1744-683X
    ISSN (online) 1744-6848
    ISSN 1744-683X
    DOI 10.1039/c6sm02007k
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Book ; Online ; Thesis: <dc:title>Struktur und Dynamik kolloidaler Dispersionen mit entropisch attraktiver Wechselwirkung</dc:title>

    Werner, Marcel [Verfasser] / Bartsch, Eckhard [Akademischer Betreuer]

    2019  

    Keywords Technische Chemie ; Technical Chemistry
    Subject code sg660
    Language German
    Publisher Universität
    Publishing place Freiburg
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

    Full text online

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  7. Book ; Conference proceedings: Bodenmanagement in Ländlichen Regionen

    Bartsch, Eckhard / Schröder, Wulf

    anlässlich des 70. Geburtstags vom Ehrenmitglied der Hessischen Akademie Ländlicher Raum Herrn Prof. Dr.-Ing. Bartsch, Präsident a.D. des HLVA ; [Referatesammlung des Seminars am 21. Oktober 2005 im Amt für Bodenmanagement Limburg a.d. Lahn, Dienstgebäude Wiesbaden]

    (Arbeitsbericht / Hessische Akademie der Forschung und Planung im Ländlichen Raum ; 15 ; Schriften der Hessischen Akademie der Forschung und Planung im Ländlichen Raum (HAL))

    2006  

    Institution Seminar Bodenmanagement in Ländlichen Regionen
    Event/congress Seminar Bodenmanagement in Ländlichen Regionen (2005.10.21, LimburgLahn)
    Author's details [Leitung: Wulf Schröder]
    Series title Arbeitsbericht / Hessische Akademie der Forschung und Planung im Ländlichen Raum ; 15
    Schriften der Hessischen Akademie der Forschung und Planung im Ländlichen Raum (HAL)
    Language German
    Size 67 S., Ill. (überw. farb.), graph. Darst., Kt.
    Publisher Hess. Akad. der Forschung und Planung im Ländlichen Raum
    Publishing place Kassel
    Document type Book ; Conference proceedings
    ISBN 3928069586 ; 9783928069588
    Database Former special subject collection: coastal and deep sea fishing

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  8. Book ; Conference proceedings: Landwirtschaft, Landschaftspflege und Fremdenverkehr

    Bartsch, Eckhard

    Entwicklungsfaktoren im Odenwald ; Seminar am 19. Juni 1998 im Lehrsaal der Firma Bosch in Erbach/Odenwald ; eine Veranstaltung im Rahmen des Hessentages 1998

    (Schriften der Hessischen Akademie der Forschung und Planung im ländlichen Raum ; 18)

    1998  

    Institution Hessentag
    Event/congress Hessentag (38, 1998, ErbachOdenwald) ; Seminar (1998.06.19, ErbachOdenwald)
    Author's details unter der Leitung von Eckhard Bartsch
    Series title Schriften der Hessischen Akademie der Forschung und Planung im ländlichen Raum ; 18
    Language German
    Size 93 S, Ill., graph. Darst., Kt
    Publisher Hess. Akad. der Forschung und Planung im ländlichen Raum
    Publishing place Kassel
    Document type Book ; Conference proceedings
    ISBN 3928069322 ; 9783928069328
    Database Former special subject collection: coastal and deep sea fishing

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  9. Book ; Conference proceedings: Landwirtschaft, Landschaftspflege und Fremdenverkehr

    Bartsch, Eckhard

    Entwicklungsfaktoren im Odenwald ; Seminar am 19. Juni 1998 im Lehrsaal der Firma Bosch in Erbach/Odenwald ; eine Veranstaltung im Rahmen des Hessentages 1998

    (Schriften der Hessischen Akademie der Forschung und Planung im ländlichen Raum ; 18)

    1998  

    Institution Hessentag
    Event/congress Hessentag (38, 1998, ErbachOdenwald) ; Seminar (1998.06.19, ErbachOdenwald)
    Author's details unter der Leitung von Eckhard Bartsch
    Series title Schriften der Hessischen Akademie der Forschung und Planung im ländlichen Raum ; 18
    Language German
    Size 93 S, Ill., graph. Darst., Kt
    Publisher Hess. Akad. der Forschung und Planung im ländlichen Raum
    Publishing place Kassel
    Document type Book ; Conference proceedings
    ISBN 3928069322 ; 9783928069328
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  10. Article ; Online: Synthesis of photo-cross-linkable microgel colloids for cluster formation studies.

    Zillessen, Andreas / Bartsch, Eckhard

    Langmuir : the ACS journal of surfaces and colloids

    2010  Volume 26, Issue 1, Page(s) 89–96

    Abstract: In many physical processes involving colloidal particles, transient structures (e.g., in transient particle gels, phase-separating suspensions) are created. Freezing these structures by chemically inter-cross-linking the particles could be an intriguing ... ...

    Abstract In many physical processes involving colloidal particles, transient structures (e.g., in transient particle gels, phase-separating suspensions) are created. Freezing these structures by chemically inter-cross-linking the particles could be an intriguing route to create network structures with special (e.g., mechanical) properties. Alternatively, photochemically fixing transient structures, thereby making them accessible to detailed analysis, could provide new insight in processes such as colloidal aggregation or crystal nucleation, which are of fundamental importance for soft matter physics as well as for applications. For this purpose we synthesized microgel particles, which carry photoreactive groups on the surface, and explored the possibility of creating chemical interparticle cross-links by UV illumination. Via seeded growth emulsion polymerization, we synthesized monodisperse polystyrene microgels with a radius of about 210 nm. In organic solvents, the particles swell to a hydrodynamic radius of 350 nm. These polystyrene microgels were functionalized by using a polymer analogous Friedel-Crafts benzoylation to introduce benzophenone groups onto the surface. The colloidal particles were characterized by static and dynamic light scattering, optical microscopy, and transmission electron microscopy. The interparticle cross-linking behavior of the modified microgels in concentrated dispersions was examined by dynamic light scattering and optical and scanning electron microscopy. To study the effect of short-range attractive forces between the particles, linear polystyrene chains acting as depletion agents were added. In time-dependent irradiation studies, we observe a coexistence of individual particles and clusters with a size range around 2 mum in radius already at shortest irradiation times upon addition of linear polymer. These (transient) clusters-introduced by depletion attraction-are permanently fixed by photo-cross-linking and, thus, on dilution of the system made amenable to analysis by light scattering.
    Language English
    Publishing date 2010-01-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/la9021454
    Database MEDical Literature Analysis and Retrieval System OnLINE

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