E. Donth

Universitätsklinikum Halle (Saale), Halle-on-the-Saale, Saxony-Anhalt, Germany

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Publications (84)180.01 Total impact

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    E. Donth
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    ABSTRACT: A DO paper of 2008 is exemplarily commented to demonstrate the general risk that the development of a new paradigm for astroparticle physics can be hindered by the work of large collaborations. This paper allows sharp formulations because only the simplest Higgs variant is treated. PACS numbers: 01.10 Hx, 13.85 Rm, 14.80 Bn Comment: stylistic improvement in second version
    Preview · Article · Jun 2009
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    E. Donth
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    ABSTRACT: Culminating-point filter construction for particle points is distinguished from torus construction for wave functions in the tangent objects of their neighborhoods. Both constructions are not united by a general manifold diffeomorphism, but are united by a map of a hidden conformal $S^{1}\times S^{3}$ charge with harmonic (Maxwell) potentials into a physical space formed by culminating points, tangent objects, and Feynman connections. The particles are obtained from three classes of eigensolutions of the homogeneous potential equations on $S^{1}\times S^{3}$. The map of the $u(2)$ invariant vector fields into the Dirac phase factors of the connections yields the electro-weak Lagrangian with explicit mass operators for the massive leptons. The spectrum of massive particles is restricted by the small, manageable number of eigensolution classes and an instability of the model for higher mass values. This instability also defines the huge numbers of filter elements needed for the culminating points. Weinberg angle, current coupling constant, and lepton masses are calculated or estimated from the renormalization of filter properties. Consequences for particle astrophysics follow, on the one hand, from the restriction of particle classes and, on the other hand, from the suggestion of new particles from the three classes e.g. of dark matter, of a confinon for the hadrons, and of a prebaryon. Definitely excluded are e.g. SUSY constructions, Higgs particles, and a quark gluon plasma: three-piece phenoma from the confinons are always present. Comment: correction of references in table 1
    Preview · Article · Jan 2009
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    E. Donth
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    ABSTRACT: A new thermodynamics for liquids related to von Laue's approach (1917) substitutes some particle priors of Gibb's rational thermodynamics. This allows the definition of a new dynamic entity ($G$ defect) whose diffusion properties also claim a largest causal region ($F$ speckle). In the frame of the hidden charge model \cite{this part} it is discussed, whether this new thermodynamics can be applied to an initial liquid for cosmology, where the $G$ defects lead to the later galaxies and the $F$ speckles to a finite expanding universe of diameter $R$. Far below a "hadronic" Compton wave length $\lambda_{0}$ of order 1 fermi, $R\ll \lambda_{0}$, there is no room left for too small filter elements, that would, however, be necessary for a filter convergence to an isolated cold quantum mechanical point particle. When the expansion of the universe comes to $\lambda_{0}$, i.e. for $R\approx \lambda_{0}$, then many hadrons are created. The related negative pressure gets large amounts and leads to an intense hadronic cosmological inflation. -- The $G$ defects are formed by the shaping power of Levy distribution (preponderant component, hierarchy, damping factor). A relation between the number of galaxies, the tilt in the density fluctuation, and the temperature amplitude of the CMB is obtained. For $R\gg \lambda_{0}$ (much vacuum), the "electromagnetic" $M_4$ tangent objects are large and flat. This allows a geometric interpretation of the "stony" dark energy as flatness on the "golden" side of the Einstein equation, $\Omega_{\Lambda}=1-\Omega_{M}$. Comment: short note added in text
    Preview · Article · Jan 2009
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    E. Donth
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    ABSTRACT: This theoretical paper is to advance a phenomenological, quasi thermodynamic approach to the dynamics of classical liquids which uses the Levy distribution of probability theory. Doubts from the chemical physics community about the application of its unusual properties to this field are tried to be removed. In particular, to understand the preponderant component of the Levy sum for Glarum Levy defects and Fischer speckles, the classical mathematical proof [D. A. Darling, Trans. Amer. Math. Soc. 73, 95 (1952)] for the existence and the influence of this component is accompanied by addition of physical arguments related to these defects. It is tried to explain an underlying fluctuating spatial pattern of free volume with weak contrast and a pattern of mobility with strong contrast, and to explain the characteristic lengths for the main transition and the Fischer modes. The structure of the relaxation chart (dynamic glass transition) and several properties of, and relations between, the slower dispersion zones therein, are reviewed for classical glassforming liquids of moderate complexity. For the main transition, the preponderant component is pushed in the midst of the defect and induces the molecule to its diffusion step across the cage door of the next neighbors. An Experimentum Crucis for an indirect proof of the existence of defects - via characteristic lengths - is also described.
    Preview · Article · Jan 2009
  • E Donth
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    ABSTRACT: The experimental information about the characteristic length of the dynamic glass transition and its temperature dependence is collected. Extrapolation to the splitting region (several 10 K above Tg) gives a length of very few nanometers. Using arguments from thermodynamic fluctuation theory it is concluded that a sharp kinetic transition temperature Tc > Tg is not possible for such small lengths.
    No preview · Article · Jan 2007 · Physica Scripta
  • E Donth
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    ABSTRACT: A chain of ideas is described connecting the theory of quantum-mechanical experiments with practical research in the relaxation of liquids, biological materials, and materials science. The chain culminates at the proposal of an experimentum crucis comparing dynamic neutron scattering, dynamic calorimetry, and computer simulation of the same substances at the crossover region of the dynamic glass transition. The conclusiveness of the experimentum crucis backwards the chain is discussed. The role of relaxation of liquids in confining geometries is also discussed, especially with respect to the confirmation of the von Laue variant for the characteristic length of glass transition as alternative to their Gibbs treatment that results in too large lengths.
    No preview · Article · Oct 2003 · The European Physical Journal E
  • R. Unger · E. Donth
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    ABSTRACT: By means of DSC, connections between melt crystallization (Tc) and melting temperatures (Tm) of block copolymers have been studied as depending on the compatibility of the block copolymer components. As examples for a compatible and an incompatible system, the systems poly(ethylene oxide) (PEO, crystalline)-poly(methyl methacrylate) (PMMA, amorphous) and PEO/poly(tert.-butyl methacrylate) (PTBMA, amorphous), respectively, were used. The compatibility of both systems is described. In block copolymers of compatible components, Tc depends on the composition, but it is less than in comparable blends. Provided a sufficient crystallization time is available, Tm is, in effect, only dependent on the PEO molecular weight. In block copolymers of incompatible components both Tc and Tm were strongly determined by molecular weights of all blocks of both components and, connected with that, by PEO domain sizes. Tc vs. Tm diagrams are presented and discussed.Mittels DSC-Untersuchungen wurden Zusammenhänge zwischen Kristallisations- (Tc) und Schmelztemperaturen (Tm) in Blockcopolymeren in Abhängigkeit von der Verträglichkeit der Copolymerkomponenten für die Kristallisation aus der Schmelze untersucht. Als Beispiel für ein verträgliches System wurde Poly(ethylenoxid) (PEO, kristallin)-Poly(methylmethacrylat) (PMMA, amorph) ausgewählt; das unverträgliche System ist PEO-Poly(tert.-butylmethacrylat) (PTBMA, amorph). Das Verträglichkeitsverhalten beider Systeme wird beschrieben. In Blockcopolymeren aus verträglichen Komponenten hängt Tc von der Zusammensetzung ab, jedoch ist Tc geringer als in vergleichbaren Blends. Ausreichende Kristallisationszeit vorausgesetzt, hängt Tm im wesentlichen nur von der PEO-Blockmolmasse ab. In Blockcopolymeren aus unverträglichen Komponenten werden sowohl Tc als auch Tm stark von den Blockmolmassen der Einzelkomponenten und den damit verbundenen PEO-Domänengrößen bestimmt. Es werden Tc-Tm-Diagramme vorgestellt und diskutiert.
    No preview · Article · Apr 2003 · Acta Polymerica
  • E. Donth
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    ABSTRACT: Molecular weights of cooperatively rearranging regions (CRRs) in polystyrene and in the styrene microphases of styrenedimethylsiloxane diblock copolymers at the glass temperature are estimated from experimental data of the glass transition published by Krause et al. (Macromolecules 15 (1982) 105). A typical order of 104 is obtained for the samples of high molecular weights. For low molecular weight (< 3 × 104) of the styrene blocks some parallelism between the size of CRRs and the molecular weights of the styrene blocks is observed. A method for discerning between thermal fluctuations and additional microheterogeneities is suggested. Die Molmassen der kooperativen Umlagerungsbereiche (CRR) in Polystyren und in den Styren-Mikrophasen von Styren-Dimethylsiloxan-Diblock-Copolymeren bei der Glasübergangstemperatur wurden aus experimentellen Daten von Krause (Macromolecules 15 (1982) 105) über den Glasübergang abgeschätzt. Für die Proben mit hoher Molmasse wurde eine typische Größenordnung von 104 g/mol erhalten. Für niedrige Molmassen (< 3·104) der Styrenblöcke wird ein gewisser Parallelismus zwischen der Größe der CRR und der Molmasse der Styrenblöcke beobachtet. Eine Methode zur Unterscheidung zwischen thermischen Fluktuationen und zusätzlichen Mikroheterogenitäten wird vorgeschlagen.
    No preview · Article · Apr 2003 · Acta Polymerica
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    ABSTRACT: Hindering and final blocking of the normal melt crystallization in central ethylene oxide (EO) blocks by methyl methacrylate (MMA) end blocks of increasing lengths in ABA type triblock copolymers synthesized anionically in a new way are investigated by differential scanning calorimetry and X-ray scattering. Experimental studies of glass transitions, low temperature nucleation, and the morphologic ten-nanometer structure are included. Low percentage amounts of long homo-PEO chains can crystallize in an ABA matrix which otherwise is not normally crystallizable. It is concluded from the experiments that in our systems with PEO molecular masses up to 50 000 g/mol the motion of the chain ends is necessary for melt crystallization under normal conditions. Die Behinderung und letztliche Blockierung der normalen Schmelzkristallisation von zentralen Ethylenoxid[EO]-Blöcken durch Methylmethacrylat-(MMA)-Endblöcke ansteigender Läange in Triblockcopolymeren vom Typ ABA, anionisch auf einem neuen Weg synthetisiert, wurden mit Hilfe der differentiellen Scanning-Calorimetrie und der Röntgenstreuung untersucht. Experimentelle Untersuchungen des Glasiihergangs, der Keimbildung bei tiefen Temperaturen und der morphologischen Zehn-Nanometer-Struktur werden eingeschlossen. Geringe Mengen (Prozentbereich) langer Homo-PEO-Ketten können in einer ABA-Matrix kristallisieren, welche sonst normal nicht kristallisierbar ist. Aus den Experimenten wird geschlossen, daß in den untersuchten Systemen mit PEO-Molekiilmassen bis zu 50 000 g/mol eine Bewegung der Kettenenden notwendig ist fur die Schmelzkristallisation unter normalen Bedingungen.
    No preview · Article · Mar 2003 · Acta Polymerica
  • E. Donth · K. Schneider
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    ABSTRACT: The phenomenological interpretation of shear curves is refined by application of the fluctuation dissipation theorem and the WIENER-KHINTCHIN theorem. The loss peaks of shear modulus and compliance near the glass transition of amorphous polymers can be attributed to two different molecular motions. An interpretation of the two peaks by one kind of molecular motion (uniform model) would imply that its flanks two logarithmic frequency decads away from the center were significantly more intensive than other molecular motions at these frequencies.Die phänomenologische Interpretation der Scherkurven wird verfeinert durch die Anwendung des Fluktuation-Dissipation-Theorems und des WIENER-CHINČIN-Theorems. Die Verlustmaxima des Schermoduls und der Schernachgiebigkeit am Glasübergang amorpher Polymere können zwei verschiedenen molekularen Bewegungen zugeordnet werden. Eine Interpretation der zwei Maxima durch eine Art molekularer Bewegungen (uniformes Modell) würde implizieren, daß ihre Flanken in einer Entfernung von zwei logarithmischen Dekaden vom Zentrum signifikant intensiver wären als andere molekulare Bewegungen bei diesen Frequenzen.
    No preview · Article · Mar 2003 · Acta Polymerica
  • E. Donth · K. Schneider
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    ABSTRACT: A survey of transition phenomenology in amorphous entangled polymers is presented. Using a general scaling hypothesis characteristic lengths are systematically attached to the different zones of the multiple glass transition. New experimental results show the location of caloric spectra between the peaks of G″ and J″ on the common frequency scale. A fine structure of the main transition is suggested. There are two components: (i) The proper glass transition zone with mode lengths up to 2 nm. This length scale is determined from the caloric spectra. (ii) The hindering zone of cooperative motion of polymer chain segments between entanglement points with mode lengths up to 10 nm. Ein Überblick der Relaxationsphänomenologie in amorphen verschlauften Polymeren wird gegeben. Unter Benutzung einer allgemeinen Skalenhypothese werden den verschiedenen Zonen des multiplen Glasübergangs systematisch charakteristische Längen zugeordnet. Neue experimentelle Ergebnisse zeigen, daß auf einer gemeinsamen Frequenzskale die kalorischen Spektren zwischen den Maxima von G″ und J″ liegen. Eine Feinstruktur des Hauptübergangs wird vorgeschlagen. Es gibt zwei Komponenten: 1. Die eigentliche Glasübergangszone mit Modenlängen bis zu 2 nm. Diese Länge wird aus kalorischen Spektren erhalten. 2. Eine Behinderungszone der kooperativen Bewegung von Polymerkettensegmenten zwischen den Verschlaufungen mit Modenlänge bis zu 10 nm.
    No preview · Article · Mar 2003 · Acta Polymerica
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    E. Donth · C. Austen Angell

    Full-text · Article · Dec 2002 · Physics Today
  • E. Donth
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    ABSTRACT: The dynamic approach to the glass transition is described on the basis of the von Laue approach to thermodynamic fluctuations leading to a Levy situation for the corresponding subsystems. The configurational approach is described on the basis of the Mezard Parisi scenario using the Gibbs distribution for the calculation of an ideal glass transition at the Kauzmann temperature. Two kinds of calorimetric experiments are described which are consistent with the von Laue approach to subsystem fluctuations and which are inconsistent with the Gibbs approach to subensemble fluctuations. A specific dynamic approach is described that is not consistent with the configurational ideal glass transition. Several examples of dynamic glass transition phenomena, for different processes in the Arrhenius diagram, can qualitatively be explained by the extraordinary concentration of free volume in relatively small spatial spots caused by the preponderant Levy component for spectral densities of fluctuations for extensive thermodynamic variables.
    No preview · Article · Sep 2002 · Journal of Non-Crystalline Solids
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    K Schröter · E Donth
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    ABSTRACT: The dynamic shear response of six glass formers (the epoxy resin diglycidyl ether of bisphenol-A, propylene carbonate, glycerol, two bulk metallic glasses, and a soda lime glass) from different substance classes with widely differing fragility is compared: No correlation of the shear Kohlrausch exponent with fragility was observed. A comparison of shear with multidimensional NMR results on glycerol is compatible with dynamic heterogeneity in glass formers having mobile islands in a lesser mobile matrix.
    Full-text · Article · Sep 2002 · Journal of Non-Crystalline Solids
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    E. Hempel · M. Beiner · H. Huth · E. Donth
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    ABSTRACT: Dielectric and mechanical relaxation processes in the series of poly(n-alkyl methacrylates) (PnAMA) depend systematically on the number of carbons in the alkyl part of the side chain. The crossover region of the dynamic glass transition shifts to lower frequencies for increasing this C number and reaches, above the hexyl member (C = 6), frequencies accessible to the temperature modulated DSC (TMDSC). The whole series from C = 1 (poly(methyl methacrylate), PMMA) to C = 11, the undecyl member is investigated by TMDSC and enthalpy retardation with DSC. The calorimetric result in the series are compared with the dielectric and mechanical data and are discussed with respect to the crossover region and a polyethylene-like glass transition (alpha(PE) process) due to a nanophase separation in these homopolymers. (C) 2002 Elsevier Science B.V. All rights reserved.
    Full-text · Article · Aug 2002 · Thermochimica Acta
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    E. Donth · E. Hempel
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    ABSTRACT: Structural relaxation is understood as the relaxation from a non-equilibrium glass state towards the equilibrium, and not from only the non-ergodic glass zone of the equilibrium liquid to the ergodic liquid or flow zone of the equilibrium liquid (response across the dynamic glass transition). Structural relaxation is, therefore, usually connected with temperatures below the glass temperature Tg. For short pulses or large heating or cooling rates Ṫ we get, however, structural relaxation also in a certain temperature range above Tg. Non-linearity for structural relaxation and equilibrium response are compared. Single and double pulse responses above the glass temperature are analyzed by simulation with the Narayanaswamy Moynihan model. The model substance parameters are chosen to be similar to those of polyvinylacetate. For steep pulse flanks of |Ṫ|=480 K/min (as, e.g., for optical experiments), we obtain surprisingly long exchange times, e.g., up to 7 s at a temperature 10 K above Tg, where the τKWW equilibrium time of the α process is only 0.52 s.
    Preview · Article · Jul 2002 · Journal of Non-Crystalline Solids
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    H Huth · M Beiner · S Weyer · M Merzlyakov · C Schick · E Donth
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    ABSTRACT: The influence of experimental uncertainties of calorimetric parameters from heat capacity spectroscopy on the temperature-dependent glass transition cooperativity Nα from the fluctuation approach is studied. Glass transition parameters from 3ω method and temperature modulated DSC are compared. The influence of the stationary temperature field on the output of the 3ω method is studied. Special advantages and disadvantages of 3ω method and temperature modulated DSC for the determination of glass transition cooperativity are discussed. It is confirmed that the temperature-dependent cooperativity indicates, independent from experimental uncertainties, a cooperativity onset in the crossover region. The extrapolated onset temperature Ton from calorimetry is shown to be comparable with other, independently obtained crossover temperatures for polystyrene and styrene butadiene rubber (SBR 1500).
    Full-text · Article · Oct 2001 · Thermochimica Acta
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    ABSTRACT: Heat capacity in the 1 K range and close to Tg was studied in a series of poly(n-alkyl methacrylate)s, PnAMA, including some random copolymers. We report on two findings: (i) The glass transition temperature Tg and the cooperativity of the α process that freezes-in at Tg, Nα(Tg), decrease smoothly between methyl (PMMA) and hexyl member (PnHMA); the cooperativity from Nα(Tg) = 35 to Nα(Tg) ≈ 1. (ii) The tunnel density measured in the 1 K range as c1 constant of the heat capacity function increases between PMMA and the ethyl member (PEMA), shows, after a maximum near PEMA, a sharp drop (factor of 6) to the butyl member (PnBMA), and remains constant at a low level up to the octyl member (PnOMA). The cooperativity of the α process near Tg and the tunnel density will be correlated assuming that freezing-in (vitrification) fixes the dynamic heterogeneity in the self-organized equilibrium liquid near Tg. We try to explain how freezing of dynamic heterogeneities in the PnAMA series is responsible for the trend in the tunnel density including the sharp drop: Freezing-in of cooperativity shells around Glarum defects forms some vaults that enlarge the free volume near these defects in comparison to a situation without vaults. The maximum in c1 is promoted by this additional free volume; the drop in c1 is caused by a vault breakdown effect if the cooperativity shell is too small for vault formation, Nα(Tg) < 15.
    No preview · Article · Jul 2001 · Macromolecules
  • E. Donth · H. Huth · M. Beiner
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    ABSTRACT: Three lengths for the dynamic glass transition will be compared: a kinematic length from computer simulation, a heterogeneity length from multidimensional nuclear magnetic resonance, and a characteristic length from calorimetry. A qualitatively consistent picture is obtained after discussion of their different origins. The difficulties with respect to measured and simulated lengths are exposed. Heat capacity spectroscopy data for temperatures and frequencies near and above the crossover region of the dynamic glass transition are reported for two substances: poly(n-decyl methacrylate), PnDMA, and 6-(4-benzyl oxy phenyl)-1, 2, 3, 4 tetraphenyl fulvene, TPCP-BO.
    No preview · Article · Jun 2001 · Journal of Physics Condensed Matter
  • E. Donth
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    ABSTRACT: In an earlier Letter to the Editor (Donth E, Hempel E and Schick C 2000 J. Phys.: Condens, Matter. 12L281) it was shown that the characteristic length of the dynamic glass transition in confined geometries favours the von Laue approach to thermodynamics over the Gibbs approach. In the present paper the two approaches are compared as regards their ability to describe temperature fluctuations and statistically independent nanometre subsystems representative for linear response of the whole sample. It is discussed why the dynamic glass transition can reflect properties of a quantum mechanical (qm) experiment (measurement process). The fluctuation-dissipation theorem (FDT) is interpreted as an equation describing a stationary succession of such experiments. The thermodynamics constructed from such an FDT is consistent with the second law: this law is inherent and the time arrow follows merely from the properties of the qm experiments
    No preview · Article · Dec 2000 · Journal of Physics Condensed Matter

Publication Stats

3k Citations
180.01 Total Impact Points

Institutions

  • 1994-2007
    • Universitätsklinikum Halle (Saale)
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 1993-2002
    • Martin Luther University Halle-Wittenberg
      Halle-on-the-Saale, Saxony-Anhalt, Germany
  • 2000
    • University of Rostock
      Rostock, Mecklenburg-Vorpommern, Germany
  • 1984-1992
    • Hochschule Merseburg
      Merseburg, Saxony-Anhalt, Germany
  • 1983
    • University of Leipzig
      Leipzig, Saxony, Germany