---
_id: '58492'
abstract:
- lang: eng
text: A coupled finite plasticity ductile damage and failure model is proposed for
the finite element simulation of clinch joining, which incorporates stress-state
dependency and regularisation by gradient-enhancement of the damage variable.
Ductile damage is determined based on a failure indicator governed by a failure
surface in stress space. The latter is exemplary chosen as a combination of the
Hosford–Coulomb and Cockcroft–Latham–Oh failure criteria for the high and low
stress triaxiality range, respectively, to cover the wide stress range encountered
in forming. Damage is coupled to elasto-plasticity to capture the damage-induced
degradation of the stiffness and flow stress. This affects the material behaviour
up to failure, thereby realistically altering the stress state. Consequently,
especially for highly ductile materials, where substantial necking and localisation
precede material fracture, the failure prediction is enhanced. The resulting stress
softening is regularised by gradient-enhancement to obtain mesh-objective results.
The analysis of a modified punch test experiment emphasises how the damage-induced
softening effect can strongly alter the actual stress state towards failure. Moreover,
the impact of successful regularisation is shown, and the applicability of the
damage and failure model to clinch joining is proven.
article_number: '106026'
article_type: original
author:
- first_name: Johannes
full_name: Friedlein, Johannes
last_name: Friedlein
- first_name: Julia
full_name: Mergheim, Julia
last_name: Mergheim
- first_name: Paul
full_name: Steinmann, Paul
last_name: Steinmann
citation:
ama: Friedlein J, Mergheim J, Steinmann P. Modelling of stress-state-dependent ductile
damage with gradient-enhancement exemplified for clinch joining. Journal of
the Mechanics and Physics of Solids. 2025;196. doi:10.1016/j.jmps.2025.106026
apa: Friedlein, J., Mergheim, J., & Steinmann, P. (2025). Modelling of stress-state-dependent
ductile damage with gradient-enhancement exemplified for clinch joining. Journal
of the Mechanics and Physics of Solids, 196, Article 106026. https://doi.org/10.1016/j.jmps.2025.106026
bibtex: '@article{Friedlein_Mergheim_Steinmann_2025, title={Modelling of stress-state-dependent
ductile damage with gradient-enhancement exemplified for clinch joining}, volume={196},
DOI={10.1016/j.jmps.2025.106026},
number={106026}, journal={Journal of the Mechanics and Physics of Solids}, publisher={Elsevier
BV}, author={Friedlein, Johannes and Mergheim, Julia and Steinmann, Paul}, year={2025}
}'
chicago: Friedlein, Johannes, Julia Mergheim, and Paul Steinmann. “Modelling of
Stress-State-Dependent Ductile Damage with Gradient-Enhancement Exemplified for
Clinch Joining.” Journal of the Mechanics and Physics of Solids 196 (2025).
https://doi.org/10.1016/j.jmps.2025.106026.
ieee: 'J. Friedlein, J. Mergheim, and P. Steinmann, “Modelling of stress-state-dependent
ductile damage with gradient-enhancement exemplified for clinch joining,” Journal
of the Mechanics and Physics of Solids, vol. 196, Art. no. 106026, 2025, doi:
10.1016/j.jmps.2025.106026.'
mla: Friedlein, Johannes, et al. “Modelling of Stress-State-Dependent Ductile Damage
with Gradient-Enhancement Exemplified for Clinch Joining.” Journal of the Mechanics
and Physics of Solids, vol. 196, 106026, Elsevier BV, 2025, doi:10.1016/j.jmps.2025.106026.
short: J. Friedlein, J. Mergheim, P. Steinmann, Journal of the Mechanics and Physics
of Solids 196 (2025).
date_created: 2025-01-31T17:04:12Z
date_updated: 2025-01-31T17:06:22Z
doi: 10.1016/j.jmps.2025.106026
intvolume: ' 196'
keyword:
- Finite plasticity
- Ductile damage
- Gradient-enhancement
- Stress-state dependency
- Failure
language:
- iso: eng
project:
- _id: '130'
grant_number: '418701707'
name: 'TRR 285: TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen
Prozessketten'
- _id: '131'
name: 'TRR 285 - A: TRR 285 - Project Area A'
- _id: '139'
name: 'TRR 285 – A05: TRR 285 - Subproject A05'
publication: Journal of the Mechanics and Physics of Solids
publication_identifier:
issn:
- 0022-5096
publication_status: published
publisher: Elsevier BV
status: public
title: Modelling of stress-state-dependent ductile damage with gradient-enhancement
exemplified for clinch joining
type: journal_article
user_id: '84990'
volume: 196
year: '2025'
...
---
_id: '63950'
abstract:
- lang: eng
text: Sodium-ion batteries are at the forefront of new, sustainable energy systems
required for the global energy transition. 23Na in situ solid-state nuclear magnetic
resonance spectroscopy is capable of unraveling structures in working electrochemical
cells during the charging and discharging processes. To evaluate its suitability
for long-term studies, local sodium environments in sodium/sodium ion cells based
on silicon carbonitride and hard carbon materials are tracked for up to 49 cycles
(228.5?h). The formation of dendrites as well as the decay of a secondary metallic
sodium species is observed, and local structures are analyzed up to the point
of capacity degradation and cell failure. Initial points of cell breakdown are
reflected in the NMR data by characteristic changes in signal intensities, whereas
the degradation of the cells is reflected by a cease to periodic signal intensity
fluctuations. Meanwhile, ex situ 23Na NMR spectra of the deactivated cells reveal
a complex range of environments for sodium ions.
author:
- first_name: Sonja
full_name: Egert, Sonja
last_name: Egert
- first_name: Renuka
full_name: Remesh, Renuka
last_name: Remesh
- first_name: Agatha Clarissa
full_name: Jusdi, Agatha Clarissa
last_name: Jusdi
- first_name: Yushi
full_name: Sugawara, Yushi
last_name: Sugawara
- first_name: Konstantin
full_name: Schutjajew, Konstantin
last_name: Schutjajew
- first_name: Martin
full_name: Oschatz, Martin
last_name: Oschatz
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
citation:
ama: Egert S, Remesh R, Jusdi AC, et al. Long-Term Cycling Stability of Sodium/Sodium
Ion Cells Probed by In Situ Solid-State NMR Spectroscopy. Batteries & Supercaps.
2025;n/a(n/a):e202500516. doi:10.1002/batt.202500516
apa: Egert, S., Remesh, R., Jusdi, A. C., Sugawara, Y., Schutjajew, K., Oschatz,
M., Buntkowsky, G., & Gutmann, T. (2025). Long-Term Cycling Stability of Sodium/Sodium
Ion Cells Probed by In Situ Solid-State NMR Spectroscopy. Batteries & Supercaps,
n/a(n/a), e202500516. https://doi.org/10.1002/batt.202500516
bibtex: '@article{Egert_Remesh_Jusdi_Sugawara_Schutjajew_Oschatz_Buntkowsky_Gutmann_2025,
title={Long-Term Cycling Stability of Sodium/Sodium Ion Cells Probed by In Situ
Solid-State NMR Spectroscopy}, volume={n/a}, DOI={10.1002/batt.202500516},
number={n/a}, journal={Batteries & Supercaps}, publisher={John Wiley &
Sons, Ltd}, author={Egert, Sonja and Remesh, Renuka and Jusdi, Agatha Clarissa
and Sugawara, Yushi and Schutjajew, Konstantin and Oschatz, Martin and Buntkowsky,
Gerd and Gutmann, Torsten}, year={2025}, pages={e202500516} }'
chicago: 'Egert, Sonja, Renuka Remesh, Agatha Clarissa Jusdi, Yushi Sugawara, Konstantin
Schutjajew, Martin Oschatz, Gerd Buntkowsky, and Torsten Gutmann. “Long-Term Cycling
Stability of Sodium/Sodium Ion Cells Probed by In Situ Solid-State NMR Spectroscopy.”
Batteries & Supercaps n/a, no. n/a (2025): e202500516. https://doi.org/10.1002/batt.202500516.'
ieee: 'S. Egert et al., “Long-Term Cycling Stability of Sodium/Sodium Ion
Cells Probed by In Situ Solid-State NMR Spectroscopy,” Batteries & Supercaps,
vol. n/a, no. n/a, p. e202500516, 2025, doi: 10.1002/batt.202500516.'
mla: Egert, Sonja, et al. “Long-Term Cycling Stability of Sodium/Sodium Ion Cells
Probed by In Situ Solid-State NMR Spectroscopy.” Batteries & Supercaps,
vol. n/a, no. n/a, John Wiley & Sons, Ltd, 2025, p. e202500516, doi:10.1002/batt.202500516.
short: S. Egert, R. Remesh, A.C. Jusdi, Y. Sugawara, K. Schutjajew, M. Oschatz,
G. Buntkowsky, T. Gutmann, Batteries & Supercaps n/a (2025) e202500516.
date_created: 2026-02-07T09:13:59Z
date_updated: 2026-02-17T16:18:23Z
doi: 10.1002/batt.202500516
extern: '1'
issue: n/a
keyword:
- solid-state nmr
- hard carbon
- in-situ
- SiCN
- sodium ion batteries
language:
- iso: eng
page: e202500516
publication: Batteries & Supercaps
publisher: John Wiley & Sons, Ltd
status: public
title: Long-Term Cycling Stability of Sodium/Sodium Ion Cells Probed by In Situ Solid-State
NMR Spectroscopy
type: journal_article
user_id: '100715'
volume: n/a
year: '2025'
...
---
_id: '63403'
abstract:
- lang: eng
text: "Stateful signatures like the NIST standardized signature schemes LMS and
XMSS provide an efficient and mature realization of post-quantum secure signature
schemes. They are recommended for long-term use cases like e.g. firmware signing.
However, stateful signature schemes require to properly manage a so-called state.
In stateful signature schemes like LMS and XMSS, signing keys consist of a set
of keys of a one-time signature scheme and it has to be guaranteed that each one-time
key is used only once. This is done by updating a state in each signature computation,
basically recording which one-time keys have already been used. While this is
straightforward in centralized systems, in distributed systems like secure enclaves
consisting of e.g. multiple hardware security modules (HSMs) with limited communication
keeping a distributed state that at any point in time is consistent among all
parties involved presents a challenge. This challenge is not addressed by the
current standardization processes. \r\nIn this paper we present a security model
for the distributed key management of post-quantum secure stateful signatures
like XMSS and LMS. We also present a simple, efficient, and easy to implement
protocol proven secure in this security model, i.e. the protocol guarantees at
any point in time a consistent state among the parties in a distributed system,
like a distributed security enclave. The security model is defined in the universal
composabilty (UC) framework by Ran Canetti by providing an ideal functionality
for the distributed key management for stateful signatures. Hence our protocol
remains secure even if arbitrarily composed with other instances of the same or
other protocols, a necessity for the security of distributed key management protocols.
Our main application are security enclaves consisting of HSMs, but the model and
the protocol can easily be adapted to other scenarios of distributed key management
of stateful signature schemes."
author:
- first_name: Johannes
full_name: Blömer, Johannes
id: '23'
last_name: Blömer
- first_name: Henrik
full_name: Bröcher, Henrik
id: '41047'
last_name: Bröcher
orcid: 0009-0008-3938-5485
- first_name: Volker
full_name: Krummel, Volker
last_name: Krummel
- first_name: Laurens Alexander
full_name: Porzenheim, Laurens Alexander
id: '47434'
last_name: Porzenheim
citation:
ama: Blömer J, Bröcher H, Krummel V, Porzenheim LA. Secure Distributed State Management
for Stateful Signatures with a Practical and Universally Composable Protocol.
apa: Blömer, J., Bröcher, H., Krummel, V., & Porzenheim, L. A. (n.d.). Secure
Distributed State Management for Stateful Signatures with a Practical and Universally
Composable Protocol.
bibtex: '@article{Blömer_Bröcher_Krummel_Porzenheim, title={Secure Distributed State
Management for Stateful Signatures with a Practical and Universally Composable
Protocol}, author={Blömer, Johannes and Bröcher, Henrik and Krummel, Volker and
Porzenheim, Laurens Alexander} }'
chicago: Blömer, Johannes, Henrik Bröcher, Volker Krummel, and Laurens Alexander
Porzenheim. “Secure Distributed State Management for Stateful Signatures with
a Practical and Universally Composable Protocol,” n.d.
ieee: J. Blömer, H. Bröcher, V. Krummel, and L. A. Porzenheim, “Secure Distributed
State Management for Stateful Signatures with a Practical and Universally Composable
Protocol.” .
mla: Blömer, Johannes, et al. Secure Distributed State Management for Stateful
Signatures with a Practical and Universally Composable Protocol.
short: J. Blömer, H. Bröcher, V. Krummel, L.A. Porzenheim, (n.d.).
date_created: 2025-12-22T21:23:22Z
date_updated: 2025-12-23T11:30:38Z
department:
- _id: '34'
- _id: '64'
keyword:
- distributed state
- hash-based signature
- stateful hash-based signature
- universal composability
- secure enclave
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://eprint.iacr.org/2025/2278.pdf
oa: '1'
page: '22'
project:
- _id: '191'
name: 'PhoQuant: Photonische Quantencomputer - Quantencomputing Testplattform'
publication_status: submitted
status: public
title: Secure Distributed State Management for Stateful Signatures with a Practical
and Universally Composable Protocol
type: preprint
user_id: '41047'
year: '2025'
...
---
_id: '56940'
abstract:
- lang: ger
text: "Ziel dieser Arbeit ist die Entwicklung eines modellbasierten Beobachters
für eingangsaffine, nichtlineare Systeme, der trotz Modellungenauigkeiten eine
hohe Schätzgüte erzielt und zusätzlich eine parametrische, physikalisch interpretierbare
Darstellung dieser ermöglicht. Diese soll zur automatisierten Verbesserung des
Modells verwendet werden. Die vorliegende Arbeit analysiert sowohl Techniken der
hybriden Systemidentifikation wie physikalisch motivierte neuronale Netze, als
auch Methoden zur Kompensation von Modellungenauigkeiten im Beobachterentwurf.
Basierend auf der Analyse wird ein neuartiger, modellbasierter Beobachter entworfen,
der Systemzustände und Modellungenauigkeiten gleichzeitig schätzt und insbesondere
eine parametrische, physikalisch interpretierbare Darstellung der Ungenauigkeiten
erzielt. Diese besteht aus einer Linearkombination von physikalisch interpretierbaren
Funktionen, deren dazugehörige, dünnbesetzt modellierte Parameter mithilfe eines
augmentierten Zustands parallel zu den Systemzuständen geschätzt werden. Das Novum
dieser Arbeit stellt somit die echtzeitfähige Schätzung von Zuständen und Modellungenauigkeiten
in physikalisch-technischer Form dar, auf deren Grundlage ein Konzept zur automatisierten
Modelladaption umgesetzt wird. Die Applikation der neuartigen Methode ist in der
Situation auftretender Systemveränderungen besonders vorteilhaft, da diese zur
Laufzeit durch den augmentierten Beobachter\r\ngeschätzt und identifiziert werden
können. "
- lang: eng
text: "The aim of this thesis is the development of a model-based observer for input-affine,
nonlinear systems that achieves a high estimation quality despite model inaccuracies.
By additionally providing a parametric, physically interpretable representation
of the model inaccuracies, an automated improvement of the model should be enabled.
This thesis\r\nanalyzes techniques of hybrid system identification such as physics-guided
neural networks, as well as methods for compensating model inaccuracies within
the observer design. Based on this analysis, a novel model-based observer is designed,
which estimates states and model inaccuracies jointly and, in particular, obtains
a parametric, physically\r\ninterpretable representation of the inaccuracies.
This consists of a linear combination of physically interpretable functions, whose
associated parameters are modeled sparse and estimated in parallel to the system’s
states using an augmented state. The novelty of this thesis is thus the real-time
capability to jointly estimate states and model inaccuracies in a physical-technical
manner, on the basis of which an automated model adaption can be\r\ncarried out.
The application of the new methodology is particularly advantageous in the situation
of occurring system changes since these can be estimated and identified at run
time by the augmented observer."
author:
- first_name: Ricarda-Samantha
full_name: Götte, Ricarda-Samantha
id: '43992'
last_name: Götte
citation:
ama: Götte R-S. Online-Schätzung von Modellungenauigkeiten zur automatischen
Modelladaption unter Beibehaltung einer physikalisch-technischen Interpretierbarkeit.
Vol 423.; 2024. doi:10.17619/UNIPB/1-2066
apa: Götte, R.-S. (2024). Online-Schätzung von Modellungenauigkeiten zur automatischen
Modelladaption unter Beibehaltung einer physikalisch-technischen Interpretierbarkeit
(Vol. 423). https://doi.org/10.17619/UNIPB/1-2066
bibtex: '@book{Götte_2024, series={Verlagsschriftenreihe des Heinz Nixdorf Instituts},
title={Online-Schätzung von Modellungenauigkeiten zur automatischen Modelladaption
unter Beibehaltung einer physikalisch-technischen Interpretierbarkeit}, volume={423},
DOI={10.17619/UNIPB/1-2066},
author={Götte, Ricarda-Samantha}, year={2024}, collection={Verlagsschriftenreihe
des Heinz Nixdorf Instituts} }'
chicago: Götte, Ricarda-Samantha. Online-Schätzung von Modellungenauigkeiten
zur automatischen Modelladaption unter Beibehaltung einer physikalisch-technischen
Interpretierbarkeit. Vol. 423. Verlagsschriftenreihe des Heinz Nixdorf Instituts,
2024. https://doi.org/10.17619/UNIPB/1-2066.
ieee: R.-S. Götte, Online-Schätzung von Modellungenauigkeiten zur automatischen
Modelladaption unter Beibehaltung einer physikalisch-technischen Interpretierbarkeit,
vol. 423. 2024.
mla: Götte, Ricarda-Samantha. Online-Schätzung von Modellungenauigkeiten zur
automatischen Modelladaption unter Beibehaltung einer physikalisch-technischen
Interpretierbarkeit. 2024, doi:10.17619/UNIPB/1-2066.
short: R.-S. Götte, Online-Schätzung von Modellungenauigkeiten zur automatischen
Modelladaption unter Beibehaltung einer physikalisch-technischen Interpretierbarkeit,
2024.
date_created: 2024-11-07T11:43:05Z
date_updated: 2024-11-07T11:47:59Z
department:
- _id: '880'
- _id: '153'
doi: 10.17619/UNIPB/1-2066
intvolume: ' 423'
keyword:
- state estimation
- joint estimation
- sparsity
language:
- iso: ger
publication_identifier:
isbn:
- 978-3-947647-42-2
publication_status: published
series_title: Verlagsschriftenreihe des Heinz Nixdorf Instituts
status: public
supervisor:
- first_name: Julia
full_name: Timmermann, Julia
id: '15402'
last_name: Timmermann
- first_name: Ralf
full_name: Mikut, Ralf
last_name: Mikut
title: Online-Schätzung von Modellungenauigkeiten zur automatischen Modelladaption
unter Beibehaltung einer physikalisch-technischen Interpretierbarkeit
type: dissertation
user_id: '43992'
volume: 423
year: '2024'
...
---
_id: '58491'
abstract:
- lang: eng
text: Similar to bulk metal forming, clinch joining is characterised by
large plastic deformations and a variety of different 3D stress states, including
severe compression. However, inherent to plastic forming is the nucleation and
growth of defects, whose detrimental effects on the material behaviour can be
described by continuum damage models and eventually lead to material failure.
As the damage evolution strongly depends on the stress state, a stress-state-dependent
model is utilised to correctly track the accumulation. To formulate and parameterise
this model, besides classical experiments, so-called modified punch tests are
also integrated herein to enhance the calibration of the failure model by capturing
a larger range of stress states and metal-forming-specific loading conditions.
Moreover, when highly ductile materials are considered, such as the dual-phase
steel HCT590X and the aluminium alloy EN AW-6014 T4 investigated here, strong
necking and localisation might occur prior to fracture. This can alter the stress
state and affect the actual strain at failure. This influence is captured by coupling
plasticity and damage to incorporate the damage-induced softening effect. Its
relative importance is shown by conducting inverse parameter identifications to
determine damage and failure parameters for both mentioned ductile metals based
on up to 12 different experiments.
article_number: '157'
author:
- first_name: Johannes
full_name: Friedlein, Johannes
last_name: Friedlein
- first_name: Max
full_name: Böhnke, Max
last_name: Böhnke
- first_name: Malte
full_name: Schlichter, Malte
last_name: Schlichter
- first_name: Mathias
full_name: Bobbert, Mathias
last_name: Bobbert
- first_name: Gerson
full_name: Meschut, Gerson
last_name: Meschut
- first_name: Julia
full_name: Mergheim, Julia
last_name: Mergheim
- first_name: Paul
full_name: Steinmann, Paul
last_name: Steinmann
citation:
ama: Friedlein J, Böhnke M, Schlichter M, et al. Material Parameter Identification
for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch
Joining. Journal of Manufacturing and Materials Processing. 2024;8(4).
doi:10.3390/jmmp8040157
apa: Friedlein, J., Böhnke, M., Schlichter, M., Bobbert, M., Meschut, G., Mergheim,
J., & Steinmann, P. (2024). Material Parameter Identification for a Stress-State-Dependent
Ductile Damage and Failure Model Applied to Clinch Joining. Journal of Manufacturing
and Materials Processing, 8(4), Article 157. https://doi.org/10.3390/jmmp8040157
bibtex: '@article{Friedlein_Böhnke_Schlichter_Bobbert_Meschut_Mergheim_Steinmann_2024,
title={Material Parameter Identification for a Stress-State-Dependent Ductile
Damage and Failure Model Applied to Clinch Joining}, volume={8}, DOI={10.3390/jmmp8040157},
number={4157}, journal={Journal of Manufacturing and Materials Processing}, publisher={MDPI
AG}, author={Friedlein, Johannes and Böhnke, Max and Schlichter, Malte and Bobbert,
Mathias and Meschut, Gerson and Mergheim, Julia and Steinmann, Paul}, year={2024}
}'
chicago: Friedlein, Johannes, Max Böhnke, Malte Schlichter, Mathias Bobbert, Gerson
Meschut, Julia Mergheim, and Paul Steinmann. “Material Parameter Identification
for a Stress-State-Dependent Ductile Damage and Failure Model Applied to Clinch
Joining.” Journal of Manufacturing and Materials Processing 8, no. 4 (2024).
https://doi.org/10.3390/jmmp8040157.
ieee: 'J. Friedlein et al., “Material Parameter Identification for a Stress-State-Dependent
Ductile Damage and Failure Model Applied to Clinch Joining,” Journal of Manufacturing
and Materials Processing, vol. 8, no. 4, Art. no. 157, 2024, doi: 10.3390/jmmp8040157.'
mla: Friedlein, Johannes, et al. “Material Parameter Identification for a Stress-State-Dependent
Ductile Damage and Failure Model Applied to Clinch Joining.” Journal of Manufacturing
and Materials Processing, vol. 8, no. 4, 157, MDPI AG, 2024, doi:10.3390/jmmp8040157.
short: J. Friedlein, M. Böhnke, M. Schlichter, M. Bobbert, G. Meschut, J. Mergheim,
P. Steinmann, Journal of Manufacturing and Materials Processing 8 (2024).
date_created: 2025-01-31T16:59:13Z
date_updated: 2025-01-31T17:03:34Z
doi: 10.3390/jmmp8040157
intvolume: ' 8'
issue: '4'
keyword:
- ductile damage
- stress-state dependency
- failure
- parameter identification
- punch test
- clinching
language:
- iso: eng
project:
- _id: '130'
grant_number: '418701707'
name: 'TRR 285: TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen
Prozessketten'
- _id: '131'
name: 'TRR 285 - A: TRR 285 - Project Area A'
- _id: '139'
name: 'TRR 285 – A05: TRR 285 - Subproject A05'
publication: Journal of Manufacturing and Materials Processing
publication_identifier:
issn:
- 2504-4494
publication_status: published
publisher: MDPI AG
status: public
title: Material Parameter Identification for a Stress-State-Dependent Ductile Damage
and Failure Model Applied to Clinch Joining
type: journal_article
user_id: '84990'
volume: 8
year: '2024'
...
---
_id: '64062'
abstract:
- lang: eng
text: Abstract Novel SBA-15-supported heterogeneous catalysts are synthesized and
applied in the Mizoroki?Heck and the Suzuki?Miyaura cross-coupling reactions in
green solvents like PEG or water. The structural properties of the products after
each synthesis step are monitored by different analytics. The amount of amine/carboxyl
groups and vanillin/histidine methyl ester and thermal stability are determined
by TGA and elemental analysis, while ICP-OES delivered the amount of palladium
of the catalysts. The morphology is investigated by SEM and XPS and confirms the
presence of coordinated palladium in the zero-oxidation state. Gas adsorption
analysis is conducted, which indicates the presence of palladium clusters in one
of the two catalysts, which is underlined by BSE images combined with EDX. A detailed
13C ssNMR and DNP-enhanced 15N ssNMR spectral analysis is presented, which provides
ultimate proof of the successful syntheses of the catalysts. The coordination
of the palladium onto the carrier material is shown by combining the NMR spectral
results with the results of the other analytics. First catalytic tests show for
the Mizoroki?Heck reaction yields up to nearly 100% and for the Suzuki-Miyaura
up to 88% in the presence of PEG and water, respectively.
author:
- first_name: Till
full_name: Wissel, Till
last_name: Wissel
- first_name: Lorenz
full_name: Rösler, Lorenz
last_name: Rösler
- first_name: Martin
full_name: Brodrecht, Martin
last_name: Brodrecht
- first_name: Mark V.
full_name: Höfler, Mark V.
last_name: Höfler
- first_name: Kevin
full_name: Herr, Kevin
last_name: Herr
- first_name: Marcos
full_name: Oliveira Jr., Marcos
last_name: Oliveira Jr.
- first_name: Vytautas
full_name: Klimavicius, Vytautas
last_name: Klimavicius
- first_name: Martin
full_name: Ebert, Martin
last_name: Ebert
- first_name: Hergen
full_name: Breitzke, Hergen
last_name: Breitzke
- first_name: Markus
full_name: Hoffmann, Markus
last_name: Hoffmann
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
citation:
ama: 'Wissel T, Rösler L, Brodrecht M, et al. Novel Heterogeneous Pd Catalysts for
Cross-Coupling Reactions in Biocompatible Media: Structural Insights from Solid-State
NMR Techniques. ChemCatChem. 2024;17:e202401511. doi:10.1002/cctc.202401511'
apa: 'Wissel, T., Rösler, L., Brodrecht, M., Höfler, M. V., Herr, K., Oliveira Jr.,
M., Klimavicius, V., Ebert, M., Breitzke, H., Hoffmann, M., Buntkowsky, G., &
Gutmann, T. (2024). Novel Heterogeneous Pd Catalysts for Cross-Coupling Reactions
in Biocompatible Media: Structural Insights from Solid-State NMR Techniques. ChemCatChem,
17, e202401511. https://doi.org/10.1002/cctc.202401511'
bibtex: '@article{Wissel_Rösler_Brodrecht_Höfler_Herr_Oliveira Jr._Klimavicius_Ebert_Breitzke_Hoffmann_et
al._2024, title={Novel Heterogeneous Pd Catalysts for Cross-Coupling Reactions
in Biocompatible Media: Structural Insights from Solid-State NMR Techniques},
volume={17}, DOI={10.1002/cctc.202401511},
journal={ChemCatChem}, publisher={John Wiley & Sons, Ltd}, author={Wissel,
Till and Rösler, Lorenz and Brodrecht, Martin and Höfler, Mark V. and Herr, Kevin
and Oliveira Jr., Marcos and Klimavicius, Vytautas and Ebert, Martin and Breitzke,
Hergen and Hoffmann, Markus and et al.}, year={2024}, pages={e202401511} }'
chicago: 'Wissel, Till, Lorenz Rösler, Martin Brodrecht, Mark V. Höfler, Kevin Herr,
Marcos Oliveira Jr., Vytautas Klimavicius, et al. “Novel Heterogeneous Pd Catalysts
for Cross-Coupling Reactions in Biocompatible Media: Structural Insights from
Solid-State NMR Techniques.” ChemCatChem 17 (2024): e202401511. https://doi.org/10.1002/cctc.202401511.'
ieee: 'T. Wissel et al., “Novel Heterogeneous Pd Catalysts for Cross-Coupling
Reactions in Biocompatible Media: Structural Insights from Solid-State NMR Techniques,”
ChemCatChem, vol. 17, p. e202401511, 2024, doi: 10.1002/cctc.202401511.'
mla: 'Wissel, Till, et al. “Novel Heterogeneous Pd Catalysts for Cross-Coupling
Reactions in Biocompatible Media: Structural Insights from Solid-State NMR Techniques.”
ChemCatChem, vol. 17, John Wiley & Sons, Ltd, 2024, p. e202401511,
doi:10.1002/cctc.202401511.'
short: T. Wissel, L. Rösler, M. Brodrecht, M.V. Höfler, K. Herr, M. Oliveira Jr.,
V. Klimavicius, M. Ebert, H. Breitzke, M. Hoffmann, G. Buntkowsky, T. Gutmann,
ChemCatChem 17 (2024) e202401511.
date_created: 2026-02-07T16:18:53Z
date_updated: 2026-02-17T16:12:41Z
doi: 10.1002/cctc.202401511
extern: '1'
intvolume: ' 17'
keyword:
- SBA-15
- Heterogeneous catalyst
- Pd cross-coupling
- Polyethylene glycol
- Solid-state DNP NMR
language:
- iso: eng
page: e202401511
publication: ChemCatChem
publication_identifier:
issn:
- 1867-3880
publisher: John Wiley & Sons, Ltd
status: public
title: 'Novel Heterogeneous Pd Catalysts for Cross-Coupling Reactions in Biocompatible
Media: Structural Insights from Solid-State NMR Techniques'
type: journal_article
user_id: '100715'
volume: 17
year: '2024'
...
---
_id: '63988'
abstract:
- lang: eng
text: This concept summarizes recent advances in development and application of
DNP enhanced multinuclear solid-state NMR to study the molecular structure and
surface functionalization of cellulose and paper-based materials. Moreover, a
novel application is presented where DNP enhanced 13C and 15N solid-state NMR
is used to identify structure moieties formed by cross-linking of hydroxypropyl
cellulose. Given these two aspects of this concept-type of article, we thus combine
both, a review on recent findings already published and unpublished recent data
that complement the existing knowledge in the field of characterization of functional
lignocellulosic materials by DNP enhanced solid-state NMR.
author:
- first_name: Mark V.
full_name: Höfler, Mark V.
last_name: Höfler
- first_name: Jonas
full_name: Lins, Jonas
last_name: Lins
- first_name: David
full_name: Seelinger, David
last_name: Seelinger
- first_name: Lukas
full_name: Pachernegg, Lukas
last_name: Pachernegg
- first_name: Timmy
full_name: Schäfer, Timmy
last_name: Schäfer
- first_name: Stefan
full_name: Spirk, Stefan
last_name: Spirk
- first_name: Markus
full_name: Biesalski, Markus
last_name: Biesalski
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
citation:
ama: Höfler MV, Lins J, Seelinger D, et al. DNP enhanced solid-state NMR – A powerful
tool to address the surface functionalization of cellulose/paper derived materials.
Journal of Magnetic Resonance Open. 2024;21:100163. doi:10.1016/j.jmro.2024.100163
apa: Höfler, M. V., Lins, J., Seelinger, D., Pachernegg, L., Schäfer, T., Spirk,
S., Biesalski, M., & Gutmann, T. (2024). DNP enhanced solid-state NMR – A
powerful tool to address the surface functionalization of cellulose/paper derived
materials. Journal of Magnetic Resonance Open, 21, 100163. https://doi.org/10.1016/j.jmro.2024.100163
bibtex: '@article{Höfler_Lins_Seelinger_Pachernegg_Schäfer_Spirk_Biesalski_Gutmann_2024,
title={DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization
of cellulose/paper derived materials}, volume={21}, DOI={10.1016/j.jmro.2024.100163},
journal={Journal of Magnetic Resonance Open}, author={Höfler, Mark V. and Lins,
Jonas and Seelinger, David and Pachernegg, Lukas and Schäfer, Timmy and Spirk,
Stefan and Biesalski, Markus and Gutmann, Torsten}, year={2024}, pages={100163}
}'
chicago: 'Höfler, Mark V., Jonas Lins, David Seelinger, Lukas Pachernegg, Timmy
Schäfer, Stefan Spirk, Markus Biesalski, and Torsten Gutmann. “DNP Enhanced Solid-State
NMR – A Powerful Tool to Address the Surface Functionalization of Cellulose/Paper
Derived Materials.” Journal of Magnetic Resonance Open 21 (2024): 100163.
https://doi.org/10.1016/j.jmro.2024.100163.'
ieee: 'M. V. Höfler et al., “DNP enhanced solid-state NMR – A powerful tool
to address the surface functionalization of cellulose/paper derived materials,”
Journal of Magnetic Resonance Open, vol. 21, p. 100163, 2024, doi: 10.1016/j.jmro.2024.100163.'
mla: Höfler, Mark V., et al. “DNP Enhanced Solid-State NMR – A Powerful Tool to
Address the Surface Functionalization of Cellulose/Paper Derived Materials.” Journal
of Magnetic Resonance Open, vol. 21, 2024, p. 100163, doi:10.1016/j.jmro.2024.100163.
short: M.V. Höfler, J. Lins, D. Seelinger, L. Pachernegg, T. Schäfer, S. Spirk,
M. Biesalski, T. Gutmann, Journal of Magnetic Resonance Open 21 (2024) 100163.
date_created: 2026-02-07T15:46:32Z
date_updated: 2026-02-17T16:16:40Z
doi: 10.1016/j.jmro.2024.100163
extern: '1'
intvolume: ' 21'
keyword:
- solid-state nmr
- dynamic nuclear polarization
- Hydroxypropyl cellulose
- Selective enhancement
- Spin labelling
language:
- iso: eng
page: '100163'
publication: Journal of Magnetic Resonance Open
status: public
title: DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization
of cellulose/paper derived materials
type: journal_article
user_id: '100715'
volume: 21
year: '2024'
...
---
_id: '63974'
abstract:
- lang: eng
text: A versatile strategy for synthesizing tailored peptide based biradicals is
presented. By labeling the protected amino acid hydroxyproline with PROXYL via
the OH functionality and using this building block in solid phase peptide synthesis
(SPPS), the obtained peptides become polarization agents for DNP enhanced solid-state
NMR in biotolerant media. To analyze the effect of the radical position on the
enhancement factor, three different biradicals are synthesized. The PROXYL spin-label
is inserted in a collagen inspired artificial peptide sequence by binding through
the OH group of the hydroxyproline moieties at specific position in the chain.
This labeling strategy is universally applicable for any hydroxyproline position
in a peptide sequence since solid-phase peptide synthesis is used to insert the
building block. High performance liquid chromatography (HPLC) and mass spectrometry
(MS) analyses show the successful introduction of the spin label in the peptide
chain and electron paramagnetic resonance (EPR) spectroscopy confirms its activity.
Dynamic nuclear polarization (DNP) enhanced solid-state nuclear magnetic resonance
(NMR) experiments performed on frozen aqueous glycerol-d8 solutions containing
these peptide radicals show significantly higher enhancement factors of up to
45 in 1H→13C cross polarization magic angle spinning (CP MAS) experiments compared
to an analogous mono-radical peptide including this building block (ε ≈ 14). Compared
to commercial biradicals such as AMUPol for which enhancement factors {\textgreater}
100 have been obtained in the past and which have been optimized in their structure,
the obtained enhancement up to 45 for our biradicals presents a significant progress
in radical design.
author:
- first_name: Kevin
full_name: Herr, Kevin
last_name: Herr
- first_name: Mark V.
full_name: Höfler, Mark V.
last_name: Höfler
- first_name: Henrike
full_name: Heise, Henrike
last_name: Heise
- first_name: Fabien
full_name: Aussenac, Fabien
last_name: Aussenac
- first_name: Felix
full_name: Kornemann, Felix
last_name: Kornemann
- first_name: David
full_name: Rosenberger, David
last_name: Rosenberger
- first_name: Martin
full_name: Brodrecht, Martin
last_name: Brodrecht
- first_name: Marcos
full_name: Oliveira, Marcos
last_name: Oliveira
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
citation:
ama: Herr K, Höfler MV, Heise H, et al. Biradicals based on PROXYL containing building
blocks for efficient dynamic nuclear polarization in biotolerant media. Journal
of Magnetic Resonance Open. 2024;20:100152. doi:10.1016/j.jmro.2024.100152
apa: Herr, K., Höfler, M. V., Heise, H., Aussenac, F., Kornemann, F., Rosenberger,
D., Brodrecht, M., Oliveira, M., Buntkowsky, G., & Gutmann, T. (2024). Biradicals
based on PROXYL containing building blocks for efficient dynamic nuclear polarization
in biotolerant media. Journal of Magnetic Resonance Open, 20, 100152.
https://doi.org/10.1016/j.jmro.2024.100152
bibtex: '@article{Herr_Höfler_Heise_Aussenac_Kornemann_Rosenberger_Brodrecht_Oliveira_Buntkowsky_Gutmann_2024,
title={Biradicals based on PROXYL containing building blocks for efficient dynamic
nuclear polarization in biotolerant media}, volume={20}, DOI={10.1016/j.jmro.2024.100152},
journal={Journal of Magnetic Resonance Open}, author={Herr, Kevin and Höfler,
Mark V. and Heise, Henrike and Aussenac, Fabien and Kornemann, Felix and Rosenberger,
David and Brodrecht, Martin and Oliveira, Marcos and Buntkowsky, Gerd and Gutmann,
Torsten}, year={2024}, pages={100152} }'
chicago: 'Herr, Kevin, Mark V. Höfler, Henrike Heise, Fabien Aussenac, Felix Kornemann,
David Rosenberger, Martin Brodrecht, Marcos Oliveira, Gerd Buntkowsky, and Torsten
Gutmann. “Biradicals Based on PROXYL Containing Building Blocks for Efficient
Dynamic Nuclear Polarization in Biotolerant Media.” Journal of Magnetic Resonance
Open 20 (2024): 100152. https://doi.org/10.1016/j.jmro.2024.100152.'
ieee: 'K. Herr et al., “Biradicals based on PROXYL containing building blocks
for efficient dynamic nuclear polarization in biotolerant media,” Journal of
Magnetic Resonance Open, vol. 20, p. 100152, 2024, doi: 10.1016/j.jmro.2024.100152.'
mla: Herr, Kevin, et al. “Biradicals Based on PROXYL Containing Building Blocks
for Efficient Dynamic Nuclear Polarization in Biotolerant Media.” Journal of
Magnetic Resonance Open, vol. 20, 2024, p. 100152, doi:10.1016/j.jmro.2024.100152.
short: K. Herr, M.V. Höfler, H. Heise, F. Aussenac, F. Kornemann, D. Rosenberger,
M. Brodrecht, M. Oliveira, G. Buntkowsky, T. Gutmann, Journal of Magnetic Resonance
Open 20 (2024) 100152.
date_created: 2026-02-07T15:42:00Z
date_updated: 2026-02-17T16:17:22Z
doi: 10.1016/j.jmro.2024.100152
extern: '1'
intvolume: ' 20'
keyword:
- solid-state nmr
- dynamic nuclear polarization
- peptides
- Biradicals
- Spin labeling
language:
- iso: eng
page: '100152'
publication: Journal of Magnetic Resonance Open
status: public
title: Biradicals based on PROXYL containing building blocks for efficient dynamic
nuclear polarization in biotolerant media
type: journal_article
user_id: '100715'
volume: 20
year: '2024'
...
---
_id: '63970'
abstract:
- lang: eng
text: Abstract Recent advances in solid-state nuclear magnetic resonance (NMR) spectroscopy,
combined with dynamic nuclear polarization (DNP), quantum chemical DFT calculations,
and gas-phase NMR spectroscopy investigating the structure and reactivity of heterogeneous
catalysts are reviewed. The investigated catalysts range from classical mononuclear
catalysts, like immobilized derivates of Wilkinson’s catalysts over binuclear
catalysts such as the dirhodium paddlewheel catalyst to catalytic nanoparticles,
employing various support materials, such as mesoporous silica gels, coordination
polymers, and biomaterials such as cellulose.
author:
- first_name: Nadia
full_name: Haro Mares, Nadia
last_name: Haro Mares
- first_name: Millena
full_name: Logrado, Millena
last_name: Logrado
- first_name: Jan
full_name: Kergassner, Jan
last_name: Kergassner
- first_name: Bingyu
full_name: Zhang, Bingyu
last_name: Zhang
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
citation:
ama: Haro Mares N, Logrado M, Kergassner J, Zhang B, Gutmann T, Buntkowsky G. Solid-State
NMR of Heterogeneous Catalysts. ChemCatChem. Published online 2024:e202401159.
doi:10.1002/cctc.202401159
apa: Haro Mares, N., Logrado, M., Kergassner, J., Zhang, B., Gutmann, T., &
Buntkowsky, G. (2024). Solid-State NMR of Heterogeneous Catalysts. ChemCatChem,
e202401159. https://doi.org/10.1002/cctc.202401159
bibtex: '@article{Haro Mares_Logrado_Kergassner_Zhang_Gutmann_Buntkowsky_2024, title={Solid-State
NMR of Heterogeneous Catalysts}, DOI={10.1002/cctc.202401159},
journal={ChemCatChem}, publisher={John Wiley & Sons, Ltd}, author={Haro Mares,
Nadia and Logrado, Millena and Kergassner, Jan and Zhang, Bingyu and Gutmann,
Torsten and Buntkowsky, Gerd}, year={2024}, pages={e202401159} }'
chicago: Haro Mares, Nadia, Millena Logrado, Jan Kergassner, Bingyu Zhang, Torsten
Gutmann, and Gerd Buntkowsky. “Solid-State NMR of Heterogeneous Catalysts.” ChemCatChem,
2024, e202401159. https://doi.org/10.1002/cctc.202401159.
ieee: 'N. Haro Mares, M. Logrado, J. Kergassner, B. Zhang, T. Gutmann, and G. Buntkowsky,
“Solid-State NMR of Heterogeneous Catalysts,” ChemCatChem, p. e202401159,
2024, doi: 10.1002/cctc.202401159.'
mla: Haro Mares, Nadia, et al. “Solid-State NMR of Heterogeneous Catalysts.” ChemCatChem,
John Wiley & Sons, Ltd, 2024, p. e202401159, doi:10.1002/cctc.202401159.
short: N. Haro Mares, M. Logrado, J. Kergassner, B. Zhang, T. Gutmann, G. Buntkowsky,
ChemCatChem (2024) e202401159.
date_created: 2026-02-07T15:40:38Z
date_updated: 2026-02-17T16:17:30Z
doi: 10.1002/cctc.202401159
extern: '1'
keyword:
- solid-state nmr
- heterogeneous catalysis
- dynamic nuclear polarization
- Nanocatalysis
- Surface-reactions
language:
- iso: eng
page: e202401159
publication: ChemCatChem
publication_identifier:
issn:
- 1867-3880
publisher: John Wiley & Sons, Ltd
status: public
title: Solid-State NMR of Heterogeneous Catalysts
type: journal_article
user_id: '100715'
year: '2024'
...
---
_id: '57816'
abstract:
- lang: eng
text: "TLS-Attacker is an open-source framework for analyzing Transport\r\nLayer
Security (TLS) implementations. The framework allows users\r\nto specify custom
protocol flows and provides modification hooks to\r\nmanipulate message contents.
Since its initial publication in 2016 by\r\nJuraj Somorovsky, TLS-Attacker has
been used in numerous studies\r\npublished at well-established conferences and
helped to identify\r\nvulnerabilities in well-known open-source TLS libraries.
To enable\r\nautomated analyses, TLS-Attacker has grown into a suite of projects,\r\neach
designed as a building block that can be applied to facilitate\r\nvarious analysis
methodologies. The framework still undergoes\r\ncontinuous improvements with feature
extensions, such as DTLS\r\n1.3 or the addition of new dialects such as QUIC,
to continue its\r\neffectiveness and relevancy as a security analysis framework."
author:
- first_name: Fabian
full_name: Bäumer, Fabian
last_name: Bäumer
- first_name: Marcus
full_name: Brinkmann, Marcus
last_name: Brinkmann
- first_name: Nurullah
full_name: Erinola, Nurullah
last_name: Erinola
- first_name: Sven Niclas
full_name: Hebrok, Sven Niclas
id: '55616'
last_name: Hebrok
orcid: 0009-0006-1172-1665
- first_name: Nico
full_name: Heitmann, Nico
id: '74619'
last_name: Heitmann
orcid: 0009-0003-7687-7044
- first_name: Felix
full_name: Lange, Felix
id: '67893'
last_name: Lange
- first_name: Marcel
full_name: Maehren, Marcel
last_name: Maehren
- first_name: Robert
full_name: Merget, Robert
last_name: Merget
- first_name: Niklas
full_name: Niere, Niklas
id: '63563'
last_name: Niere
- first_name: Maximilian Manfred
full_name: Radoy, Maximilian Manfred
id: '68826'
last_name: Radoy
orcid: 0009-0005-3059-6823
- first_name: Conrad
full_name: Schmidt, Conrad
last_name: Schmidt
- first_name: Jörg
full_name: Schwenk, Jörg
last_name: Schwenk
- first_name: Juraj
full_name: Somorovsky, Juraj
id: '83504'
last_name: Somorovsky
orcid: 0000-0002-3593-7720
citation:
ama: 'Bäumer F, Brinkmann M, Erinola N, et al. TLS-Attacker: A Dynamic Framework
for Analyzing TLS Implementations. In: Proceedings of Cybersecurity Artifacts
Competition and Impact Award (ACSAC ’24). ; 2024.'
apa: 'Bäumer, F., Brinkmann, M., Erinola, N., Hebrok, S. N., Heitmann, N., Lange,
F., Maehren, M., Merget, R., Niere, N., Radoy, M. M., Schmidt, C., Schwenk, J.,
& Somorovsky, J. (2024). TLS-Attacker: A Dynamic Framework for Analyzing TLS
Implementations. Proceedings of Cybersecurity Artifacts Competition and Impact
Award (ACSAC ’24). Annual Computer Security Applications Conference, Hawaii.'
bibtex: '@inproceedings{Bäumer_Brinkmann_Erinola_Hebrok_Heitmann_Lange_Maehren_Merget_Niere_Radoy_et
al._2024, title={TLS-Attacker: A Dynamic Framework for Analyzing TLS Implementations},
booktitle={Proceedings of Cybersecurity Artifacts Competition and Impact Award
(ACSAC ’24)}, author={Bäumer, Fabian and Brinkmann, Marcus and Erinola, Nurullah
and Hebrok, Sven Niclas and Heitmann, Nico and Lange, Felix and Maehren, Marcel
and Merget, Robert and Niere, Niklas and Radoy, Maximilian Manfred and et al.},
year={2024} }'
chicago: 'Bäumer, Fabian, Marcus Brinkmann, Nurullah Erinola, Sven Niclas Hebrok,
Nico Heitmann, Felix Lange, Marcel Maehren, et al. “TLS-Attacker: A Dynamic Framework
for Analyzing TLS Implementations.” In Proceedings of Cybersecurity Artifacts
Competition and Impact Award (ACSAC ’24), 2024.'
ieee: 'F. Bäumer et al., “TLS-Attacker: A Dynamic Framework for Analyzing
TLS Implementations,” presented at the Annual Computer Security Applications Conference,
Hawaii, 2024.'
mla: 'Bäumer, Fabian, et al. “TLS-Attacker: A Dynamic Framework for Analyzing TLS
Implementations.” Proceedings of Cybersecurity Artifacts Competition and Impact
Award (ACSAC ’24), 2024.'
short: 'F. Bäumer, M. Brinkmann, N. Erinola, S.N. Hebrok, N. Heitmann, F. Lange,
M. Maehren, R. Merget, N. Niere, M.M. Radoy, C. Schmidt, J. Schwenk, J. Somorovsky,
in: Proceedings of Cybersecurity Artifacts Competition and Impact Award (ACSAC
’24), 2024.'
conference:
end_date: 2024-12-13
location: Hawaii
name: Annual Computer Security Applications Conference
start_date: 2024-12-09
date_created: 2024-12-17T11:25:14Z
date_updated: 2025-02-27T08:02:30Z
department:
- _id: '632'
keyword:
- SSL
- TLS
- DTLS
- Protocol State Fuzzing
- Planning Based
language:
- iso: eng
publication: Proceedings of Cybersecurity Artifacts Competition and Impact Award (ACSAC
’24)
quality_controlled: '1'
status: public
title: 'TLS-Attacker: A Dynamic Framework for Analyzing TLS Implementations'
type: conference
user_id: '67893'
year: '2024'
...
---
_id: '48352'
abstract:
- lang: eng
text: Star-connected cascaded H-bridge Converters require large DC-link capacitors
to buffer the second-order harmonic voltage ripple. First, it is analytically
proven that the DC-link voltage ripple is proportional to the apparent converter
power and does not depend on the power factor for nominal operation with sinusoidal
reference arm voltages and currents. A third-harmonic zero-sequence voltage injection
with an optimal amplitude and phase angle transforms the 2nd harmonic to a 4th
harmonic DC-link voltage ripple. This reduces the voltage ripple by exactly 50%
for all power factors at steady-state at balanced conditions. However, this requires
54% additional modules for unity power factor operation and even 100% for pure
reactive power operation to account for the increased reference arm voltages due
to the large amplitude of the optimal third-harmonic injection. If not enough
modules are available, an adaptive discontinuous PWM is utilized to still minimize
the voltage ripple for the given number of modules and power factor. With a very
limited number of modules (modulation index is 1.15), the proposed method still
reduces the DC-link voltage ripple by 24.4% for unity power factor operation.
It requires the same number of modules as the commonly utilized 3rd harmonic injection
with 1/6 of the grid voltage amplitude and achieves superior results. Simulations
of a 10 kV/1 MVA system confirm the analysis.
author:
- first_name: Roland
full_name: Unruh, Roland
id: '34289'
last_name: Unruh
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
- first_name: Frank
full_name: Schafmeister, Frank
id: '71291'
last_name: Schafmeister
citation:
ama: 'Unruh R, Böcker J, Schafmeister F. An Optimized Third-Harmonic Injection Reduces
DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to 50% for all Power
Factors. In: 2023 25th European Conference on Power Electronics and Applications
(EPE’23 ECCE Europe). IEEE; 2023. doi:10.23919/epe23ecceeurope58414.2023.10264313'
apa: Unruh, R., Böcker, J., & Schafmeister, F. (2023). An Optimized Third-Harmonic
Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
50% for all Power Factors. 2023 25th European Conference on Power Electronics
and Applications (EPE’23 ECCE Europe). 2023 25th European Conference on Power
Electronics and Applications (EPE’23 ECCE Europe), Aalborg, Denmark. https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313
bibtex: '@inproceedings{Unruh_Böcker_Schafmeister_2023, title={An Optimized Third-Harmonic
Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
50% for all Power Factors}, DOI={10.23919/epe23ecceeurope58414.2023.10264313},
booktitle={2023 25th European Conference on Power Electronics and Applications
(EPE’23 ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland and Böcker, Joachim
and Schafmeister, Frank}, year={2023} }'
chicago: Unruh, Roland, Joachim Böcker, and Frank Schafmeister. “An Optimized Third-Harmonic
Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
50% for All Power Factors.” In 2023 25th European Conference on Power Electronics
and Applications (EPE’23 ECCE Europe). IEEE, 2023. https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313.
ieee: 'R. Unruh, J. Böcker, and F. Schafmeister, “An Optimized Third-Harmonic Injection
Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to 50% for all
Power Factors,” presented at the 2023 25th European Conference on Power Electronics
and Applications (EPE’23 ECCE Europe), Aalborg, Denmark, 2023, doi: 10.23919/epe23ecceeurope58414.2023.10264313.'
mla: Unruh, Roland, et al. “An Optimized Third-Harmonic Injection Reduces DC-Link
Voltage Ripple in Cascaded H-Bridge Converters up to 50% for All Power Factors.”
2023 25th European Conference on Power Electronics and Applications (EPE’23
ECCE Europe), IEEE, 2023, doi:10.23919/epe23ecceeurope58414.2023.10264313.
short: 'R. Unruh, J. Böcker, F. Schafmeister, in: 2023 25th European Conference
on Power Electronics and Applications (EPE’23 ECCE Europe), IEEE, 2023.'
conference:
end_date: 2023-09-08
location: Aalborg, Denmark
name: 2023 25th European Conference on Power Electronics and Applications (EPE'23
ECCE Europe)
start_date: 2023-09-04
date_created: 2023-10-20T07:13:32Z
date_updated: 2023-10-20T10:01:02Z
department:
- _id: '52'
doi: 10.23919/epe23ecceeurope58414.2023.10264313
keyword:
- Cascaded H-Bridge
- Solid-State Transformer
- Capacitor voltage ripple
- Zero sequence voltage
- Third harmonic injection
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/10264313
publication: 2023 25th European Conference on Power Electronics and Applications (EPE'23
ECCE Europe)
publication_identifier:
isbn:
- 979-8-3503-1678-0
publication_status: published
publisher: IEEE
quality_controlled: '1'
status: public
title: An Optimized Third-Harmonic Injection Reduces DC-Link Voltage Ripple in Cascaded
H-Bridge Converters up to 50% for all Power Factors
type: conference
user_id: '34289'
year: '2023'
...
---
_id: '64045'
abstract:
- lang: eng
text: Abstract In this work, we report on an improved cell assembly of cylindrical
electrochemical cells for 23Na in-situ solid-state NMR (ssNMR) investigations.
The cell set-up is suitable for using powder electrode materials. Reproducibility
of our cell assembly is analyzed by preparing two cells containing hard carbon
(HC) powder as working electrode and sodium metal as reference electrode. Electrochemical
storage properties of HC powder electrode derived from carbonization of sustainable
cellulose are studied by ssNMR. 23Na in-situ ssNMR monitors the sodiation/desodiation
of a Na{\textbar}NaPF6{\textbar}HC cell (cell 1) over a period of 22?days, showing
high cell stability. After the galvanostatic process, the HC powder material is
investigated by high resolution 23Na ex-situ MAS NMR. The formation of ionic sodium
species in different chemical environments is obtained. Subsequently, a second
Na{\textbar}NaPF6{\textbar}HC cell (cell 2) is sodiated for 11?days achieving
a capacity of 220?mAh/g. 23Na ex-situ MAS NMR measurements of the HC powder material
extracted from this cell clearly indicate the presence of quasi-metallic sodium
species next to ionic sodium species. This observation of quasi-metallic sodium
species is discussed in terms of the achieved capacity of the cell as well as
of side reactions of sodium in this electrode material.
author:
- first_name: Edina
full_name: Šić, Edina
last_name: Šić
- first_name: Konstantin
full_name: Schutjajew, Konstantin
last_name: Schutjajew
- first_name: Ulrich
full_name: Haagen, Ulrich
last_name: Haagen
- first_name: Hergen
full_name: Breitzke, Hergen
last_name: Breitzke
- first_name: Martin
full_name: Oschatz, Martin
last_name: Oschatz
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
citation:
ama: 'Šić E, Schutjajew K, Haagen U, et al. Electrochemical Sodium Storage in Hard
Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from
In-Situ and Ex-Situ Solid-State NMR. Chemsuschem. 2023;17:e202301300. doi:10.1002/cssc.202301300'
apa: 'Šić, E., Schutjajew, K., Haagen, U., Breitzke, H., Oschatz, M., Buntkowsky,
G., & Gutmann, T. (2023). Electrochemical Sodium Storage in Hard Carbon Powder
Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and
Ex-Situ Solid-State NMR. Chemsuschem, 17, e202301300. https://doi.org/10.1002/cssc.202301300'
bibtex: '@article{Šić_Schutjajew_Haagen_Breitzke_Oschatz_Buntkowsky_Gutmann_2023,
title={Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented
in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR},
volume={17}, DOI={10.1002/cssc.202301300},
journal={Chemsuschem}, publisher={John Wiley & Sons, Ltd}, author={Šić, Edina
and Schutjajew, Konstantin and Haagen, Ulrich and Breitzke, Hergen and Oschatz,
Martin and Buntkowsky, Gerd and Gutmann, Torsten}, year={2023}, pages={e202301300}
}'
chicago: 'Šić, Edina, Konstantin Schutjajew, Ulrich Haagen, Hergen Breitzke, Martin
Oschatz, Gerd Buntkowsky, and Torsten Gutmann. “Electrochemical Sodium Storage
in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights
from In-Situ and Ex-Situ Solid-State NMR.” Chemsuschem 17 (2023): e202301300.
https://doi.org/10.1002/cssc.202301300.'
ieee: 'E. Šić et al., “Electrochemical Sodium Storage in Hard Carbon Powder
Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and
Ex-Situ Solid-State NMR,” Chemsuschem, vol. 17, p. e202301300, 2023, doi:
10.1002/cssc.202301300.'
mla: 'Šić, Edina, et al. “Electrochemical Sodium Storage in Hard Carbon Powder Electrodes
Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State
NMR.” Chemsuschem, vol. 17, John Wiley & Sons, Ltd, 2023, p. e202301300,
doi:10.1002/cssc.202301300.'
short: E. Šić, K. Schutjajew, U. Haagen, H. Breitzke, M. Oschatz, G. Buntkowsky,
T. Gutmann, Chemsuschem 17 (2023) e202301300.
date_created: 2026-02-07T16:12:13Z
date_updated: 2026-02-17T16:13:10Z
doi: 10.1002/cssc.202301300
extern: '1'
intvolume: ' 17'
keyword:
- solid-state nmr
- hard carbon
- electrochemical cells
- in-situ characterization
- sodium
language:
- iso: eng
page: e202301300
publication: Chemsuschem
publication_identifier:
issn:
- 1864-5631
publisher: John Wiley & Sons, Ltd
status: public
title: 'Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented
in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR'
type: journal_article
user_id: '100715'
volume: 17
year: '2023'
...
---
_id: '64044'
abstract:
- lang: eng
text: Abstract Polymer-derived silicon oxycarbide ceramics (SiCO) have been considered
as potential anode materials for lithium- and sodium-ion batteries. To understand
their electrochemical storage behavior, detailed insights into structural sites
present in SiCO are required. In this work, the study of local structures in SiCO
ceramics containing different amounts of carbon is presented. 13C and 29Si solid-state
MAS?NMR spectroscopy combined with DFT calculations, atomistic modeling, and EPR
investigations, suggest significant changes in the local structures of SiCO ceramics
even by small changes in the material composition. The provided findings on SiCO
structures will contribute to the research field of polymer-derived ceramics,
especially to understand electrochemical storage processes of alkali metal/ions
such as Na/Na+ inside such networks in the future.
author:
- first_name: Edina
full_name: Šić, Edina
last_name: Šić
- first_name: Jochen
full_name: Rohrer, Jochen
last_name: Rohrer
- first_name: Emmanuel
full_name: Ricohermoso, Emmanuel
last_name: Ricohermoso
- first_name: Karsten
full_name: Albe, Karsten
last_name: Albe
- first_name: Emmanuel
full_name: Ionescu, Emmanuel
last_name: Ionescu
- first_name: Ralf
full_name: Riedel, Ralf
last_name: Riedel
- first_name: Hergen
full_name: Breitzke, Hergen
last_name: Breitzke
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
citation:
ama: 'Šić E, Rohrer J, Ricohermoso E, et al. SiCO Ceramics as Storage Materials
for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and
DFT Calculations. Chemsuschem. 2023;16:e202202241. doi:10.1002/cssc.202202241'
apa: 'Šić, E., Rohrer, J., Ricohermoso, E., Albe, K., Ionescu, E., Riedel, R., Breitzke,
H., Gutmann, T., & Buntkowsky, G. (2023). SiCO Ceramics as Storage Materials
for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and
DFT Calculations. Chemsuschem, 16, e202202241. https://doi.org/10.1002/cssc.202202241'
bibtex: '@article{Šić_Rohrer_Ricohermoso_Albe_Ionescu_Riedel_Breitzke_Gutmann_Buntkowsky_2023,
title={SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on
Structure Moieties from Solid-State NMR and DFT Calculations}, volume={16}, DOI={10.1002/cssc.202202241}, journal={Chemsuschem},
publisher={John Wiley & Sons, Ltd}, author={Šić, Edina and Rohrer, Jochen
and Ricohermoso, Emmanuel and Albe, Karsten and Ionescu, Emmanuel and Riedel,
Ralf and Breitzke, Hergen and Gutmann, Torsten and Buntkowsky, Gerd}, year={2023},
pages={e202202241} }'
chicago: 'Šić, Edina, Jochen Rohrer, Emmanuel Ricohermoso, Karsten Albe, Emmanuel
Ionescu, Ralf Riedel, Hergen Breitzke, Torsten Gutmann, and Gerd Buntkowsky. “SiCO
Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties
from Solid-State NMR and DFT Calculations.” Chemsuschem 16 (2023): e202202241.
https://doi.org/10.1002/cssc.202202241.'
ieee: 'E. Šić et al., “SiCO Ceramics as Storage Materials for Alkali Metals/Ions:
Insights on Structure Moieties from Solid-State NMR and DFT Calculations,” Chemsuschem,
vol. 16, p. e202202241, 2023, doi: 10.1002/cssc.202202241.'
mla: 'Šić, Edina, et al. “SiCO Ceramics as Storage Materials for Alkali Metals/Ions:
Insights on Structure Moieties from Solid-State NMR and DFT Calculations.” Chemsuschem,
vol. 16, John Wiley & Sons, Ltd, 2023, p. e202202241, doi:10.1002/cssc.202202241.'
short: E. Šić, J. Rohrer, E. Ricohermoso, K. Albe, E. Ionescu, R. Riedel, H. Breitzke,
T. Gutmann, G. Buntkowsky, Chemsuschem 16 (2023) e202202241.
date_created: 2026-02-07T16:11:46Z
date_updated: 2026-02-17T16:13:11Z
doi: 10.1002/cssc.202202241
extern: '1'
intvolume: ' 16'
keyword:
- NMR spectroscopy
- Ceramics
- defects
- density functional calculations
- EPR spectroscopy
language:
- iso: eng
page: e202202241
publication: Chemsuschem
publication_identifier:
issn:
- 1864-5631
publisher: John Wiley & Sons, Ltd
status: public
title: 'SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure
Moieties from Solid-State NMR and DFT Calculations'
type: journal_article
user_id: '100715'
volume: 16
year: '2023'
...
---
_id: '27186'
abstract:
- lang: eng
text: 'The presented paper aims to characterize the damage and fracture behavior
of HX340LAD Micro-Alloyed steels using small punch test. Variations with respect
to punch geometries and cutting clearance are made to describe the damage behavior
of the material under different loading conditions. Experimental investigations
are conducted to identify the crack initiation in the specimens. Furthermore,
the numerical FEM simulations are performed to identify the stress state at crack
initiation. It is shown that different stress states from shear to biaxial tension
can be achieved by changing the geometries of punch and varying the cutting clearance.
Moreover, it is presented how changing the configurations can influence the stress
state variables: Triaxiality and lode angle parameter.'
article_type: original
author:
- first_name: Mortaza
full_name: Otroshi, Mortaza
id: '71269'
last_name: Otroshi
orcid: 0000-0002-8652-9209
- first_name: Gerson
full_name: Meschut, Gerson
id: '32056'
last_name: Meschut
orcid: 0000-0002-2763-1246
citation:
ama: Otroshi M, Meschut G. Influence of cutting clearance and punch geometry on
the stress state in small punch test . Engineering Failure Analysis. 2022;136(c).
doi:10.1016/j.engfailanal.2022.106183
apa: Otroshi, M., & Meschut, G. (2022). Influence of cutting clearance and punch
geometry on the stress state in small punch test . Engineering Failure Analysis,
136(c). https://doi.org/10.1016/j.engfailanal.2022.106183
bibtex: '@article{Otroshi_Meschut_2022, title={Influence of cutting clearance and
punch geometry on the stress state in small punch test }, volume={136}, DOI={10.1016/j.engfailanal.2022.106183},
number={c}, journal={Engineering Failure Analysis}, publisher={Elsevier}, author={Otroshi,
Mortaza and Meschut, Gerson}, year={2022} }'
chicago: Otroshi, Mortaza, and Gerson Meschut. “Influence of Cutting Clearance and
Punch Geometry on the Stress State in Small Punch Test .” Engineering Failure
Analysis 136, no. c (2022). https://doi.org/10.1016/j.engfailanal.2022.106183.
ieee: 'M. Otroshi and G. Meschut, “Influence of cutting clearance and punch geometry
on the stress state in small punch test ,” Engineering Failure Analysis,
vol. 136, no. c, 2022, doi: 10.1016/j.engfailanal.2022.106183.'
mla: Otroshi, Mortaza, and Gerson Meschut. “Influence of Cutting Clearance and Punch
Geometry on the Stress State in Small Punch Test .” Engineering Failure Analysis,
vol. 136, no. c, Elsevier, 2022, doi:10.1016/j.engfailanal.2022.106183.
short: M. Otroshi, G. Meschut, Engineering Failure Analysis 136 (2022).
date_created: 2021-11-07T20:34:51Z
date_updated: 2022-04-25T07:48:20Z
department:
- _id: '157'
doi: 10.1016/j.engfailanal.2022.106183
intvolume: ' 136'
issue: c
keyword:
- Ductile damage
- stress state
- small punch test
- triaxiality
- lode angle parameter
language:
- iso: eng
publication: Engineering Failure Analysis
publication_identifier:
issn:
- 1350-6307
publication_status: published
publisher: Elsevier
quality_controlled: '1'
status: public
title: 'Influence of cutting clearance and punch geometry on the stress state in small
punch test '
type: journal_article
user_id: '71269'
volume: 136
year: '2022'
...
---
_id: '34176'
abstract:
- lang: eng
text: Cascaded H-bridge Converters (CHBs) are a promising solution in converting
power from a three-phase medium voltage of 6.6 kV...30 kV to a lower DC-voltage
in the range of 100 V...1 kV to provide pure DC power to applications such as
electrolyzers for hydrogen generation, data centers with a DC power distribution
and DC microgrids. CHBs can be interpreted as modular multilevel converters with
an isolated DC-DC output stage per module, require a large DC-link capacitor for
each module to handle the second harmonic voltage ripple caused by the fluctuating
input power within a fundamental grid period. Without a zero-sequence voltage
injection, star-connected CHBs are operated with approximately sinusoidal arm
voltages and currents. The floating star point potential enables to utilize different
zero-sequence voltage injection techniques such as a third-harmonic injection
with 1/6 of the grid voltage amplitude or a Min-Max voltage injection. Both well-known
methods have the advantage to reduce the peak arm voltage and thereby the number
of required modules by 13.4 % (to √ 3 2). This paper proves analytically that
the third-harmonic injection with 1/6 of the grid voltage amplitude reduces the
second harmonic voltage ripple by only 15.1 % compared to no-voltage injection
for unity power factor operation and balanced grid voltages. Then it is shown,
that the Min-Max injection has the often overlooked advantage of reducing the
second harmonic voltage ripple by even 18.8 %. By applying the here proposed zero-sequence
voltage injection in saturation modulation, the second harmonic voltage ripple
of the DC-link capacitors is reduced by even 24.3 %, while still requiring the
same number of modules as the Min-Max injection. For a realistic number of reserve
modules, the overall energy ripple in the DC-link capacitors is reduced by 40
%.
author:
- first_name: Roland
full_name: Unruh, Roland
id: '34289'
last_name: Unruh
- first_name: Frank
full_name: Schafmeister, Frank
id: '71291'
last_name: Schafmeister
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
citation:
ama: 'Unruh R, Schafmeister F, Böcker J. Zero-Sequence Voltage Reduces DC-Link Capacitor
Demand in Cascaded H-Bridge Converters for Large-Scale Electrolyzers by 40%. In:
24th European Conference on Power Electronics and Applications (EPE’22 ECCE
Europe). IEEE; 2022.'
apa: Unruh, R., Schafmeister, F., & Böcker, J. (2022). Zero-Sequence Voltage
Reduces DC-Link Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale
Electrolyzers by 40%. 24th European Conference on Power Electronics and Applications
(EPE’22 ECCE Europe). 24th European Conference on Power Electronics and Applications
(EPE’22 ECCE Europe), Hanover, Germany.
bibtex: '@inproceedings{Unruh_Schafmeister_Böcker_2022, title={Zero-Sequence Voltage
Reduces DC-Link Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale
Electrolyzers by 40%}, booktitle={24th European Conference on Power Electronics
and Applications (EPE’22 ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland
and Schafmeister, Frank and Böcker, Joachim}, year={2022} }'
chicago: Unruh, Roland, Frank Schafmeister, and Joachim Böcker. “Zero-Sequence Voltage
Reduces DC-Link Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale
Electrolyzers by 40%.” In 24th European Conference on Power Electronics and
Applications (EPE’22 ECCE Europe). IEEE, 2022.
ieee: R. Unruh, F. Schafmeister, and J. Böcker, “Zero-Sequence Voltage Reduces DC-Link
Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale Electrolyzers
by 40%,” presented at the 24th European Conference on Power Electronics and Applications
(EPE’22 ECCE Europe), Hanover, Germany, 2022.
mla: Unruh, Roland, et al. “Zero-Sequence Voltage Reduces DC-Link Capacitor Demand
in Cascaded H-Bridge Converters for Large-Scale Electrolyzers by 40%.” 24th
European Conference on Power Electronics and Applications (EPE’22 ECCE Europe),
IEEE, 2022.
short: 'R. Unruh, F. Schafmeister, J. Böcker, in: 24th European Conference on Power
Electronics and Applications (EPE’22 ECCE Europe), IEEE, 2022.'
conference:
end_date: 2022-09-09
location: Hanover, Germany
name: 24th European Conference on Power Electronics and Applications (EPE'22 ECCE
Europe)
start_date: 2022-09-05
date_created: 2022-12-02T12:47:38Z
date_updated: 2023-10-23T09:04:23Z
department:
- _id: '52'
keyword:
- Cascaded H-Bridge
- Solid-State Transformer
- Zero sequence voltage
- Third harmonic injection
- Capacitor voltage ripple
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9907278
publication: 24th European Conference on Power Electronics and Applications (EPE'22
ECCE Europe)
publication_identifier:
isbn:
- 978-9-0758-1539-9
publication_status: published
publisher: IEEE
status: public
title: Zero-Sequence Voltage Reduces DC-Link Capacitor Demand in Cascaded H-Bridge
Converters for Large-Scale Electrolyzers by 40%
type: conference
user_id: '34289'
year: '2022'
...
---
_id: '63948'
abstract:
- lang: eng
text: In this work, the behavior of four different commercially available polarizing
agents is investigated employing the non-ionic model surfactant 1-octanol as analyte.
A relative method for the comparison of the proportion of the direct and indirect
polarization transfer pathways is established, allowing a direct comparison of
the polarization efficacy for different radicals and different parts of the 1-octanol
molecule despite differences in radical concentration or sample amount. With this
approach, it could be demonstrated that the hydrophilicity is a key factor in
the way polarization is transferred from the polarizing agent to the analyte.
These findings are confirmed by the determination of buildup times Tb, illustrating
that the choice of polarizing agent plays an essential role in ensuring an optimal
polarization transfer and therefore the maximum amount of enhancement possible
for DNP enhanced NMR measurements.
author:
- first_name: Sonja C.
full_name: Döller, Sonja C.
last_name: Döller
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Markus
full_name: Hoffmann, Markus
last_name: Hoffmann
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
citation:
ama: Döller SC, Gutmann T, Hoffmann M, Buntkowsky G. A case study on the influence
of hydrophilicity on the signal enhancement by dynamic nuclear polarization. Solid
State Nuclear Magnetic Resonance. 2022;122:101829.
apa: Döller, S. C., Gutmann, T., Hoffmann, M., & Buntkowsky, G. (2022). A case
study on the influence of hydrophilicity on the signal enhancement by dynamic
nuclear polarization. Solid State Nuclear Magnetic Resonance, 122,
101829.
bibtex: '@article{Döller_Gutmann_Hoffmann_Buntkowsky_2022, title={A case study on
the influence of hydrophilicity on the signal enhancement by dynamic nuclear polarization},
volume={122}, journal={Solid State Nuclear Magnetic Resonance}, author={Döller,
Sonja C. and Gutmann, Torsten and Hoffmann, Markus and Buntkowsky, Gerd}, year={2022},
pages={101829} }'
chicago: 'Döller, Sonja C., Torsten Gutmann, Markus Hoffmann, and Gerd Buntkowsky.
“A Case Study on the Influence of Hydrophilicity on the Signal Enhancement by
Dynamic Nuclear Polarization.” Solid State Nuclear Magnetic Resonance 122
(2022): 101829.'
ieee: S. C. Döller, T. Gutmann, M. Hoffmann, and G. Buntkowsky, “A case study on
the influence of hydrophilicity on the signal enhancement by dynamic nuclear polarization,”
Solid State Nuclear Magnetic Resonance, vol. 122, p. 101829, 2022.
mla: Döller, Sonja C., et al. “A Case Study on the Influence of Hydrophilicity on
the Signal Enhancement by Dynamic Nuclear Polarization.” Solid State Nuclear
Magnetic Resonance, vol. 122, 2022, p. 101829.
short: S.C. Döller, T. Gutmann, M. Hoffmann, G. Buntkowsky, Solid State Nuclear
Magnetic Resonance 122 (2022) 101829.
date_created: 2026-02-07T09:13:08Z
date_updated: 2026-02-17T16:18:26Z
extern: '1'
intvolume: ' 122'
keyword:
- DNP NMR
- Dynamics
- Low temperature NMR
- Octanol
- Solid state NMR
- Surfactants
language:
- iso: eng
page: '101829'
publication: Solid State Nuclear Magnetic Resonance
status: public
title: A case study on the influence of hydrophilicity on the signal enhancement by
dynamic nuclear polarization
type: journal_article
user_id: '100715'
volume: 122
year: '2022'
...
---
_id: '63943'
abstract:
- lang: eng
text: A lithium halide exchange reaction at low-temperature, via the treatment of
2,6-di(isopropyl)phenyllithium on 1,1′-bis-(dichlorophosphino)ferrocene, resulted
in the first isolated example of an aryl-substituted diphospha [2]ferrocenophane
(diphospha [2]FCP) 2. Although compound 2 did not show any recognizable thermal
reaction at higher temperature (up to 350 °C), its tert-butyl-substituted counterpart
1 underwent a clean selective heat-mediated P–C cleavage reaction, followed
by an inter-molecular rearrangement, to produce a P–P fused bis [3]ferrocenophane
3 with all-trans oriented P-chain, which upon further heating gave a polyferrocenylphosphane
tBu-[Fc’P2]n-tBu (4). Since polymer 4 is insoluble in common organic solvents,
it has been characterized with solid-state techniques, including solid-state NMR.
Density functional theory (DFT) has further been employed to identify possible
pathways for P–C bond cleavage on 1 and 2, as well as to evaluate accessible
pathways for further polymerization toward 4.
author:
- first_name: Subhayan
full_name: Dey, Subhayan
last_name: Dey
- first_name: Denis
full_name: Kargin, Denis
last_name: Kargin
- first_name: Mark V.
full_name: Höfler, Mark V.
last_name: Höfler
- first_name: Balazs
full_name: Szathmari, Balazs
last_name: Szathmari
- first_name: Clemens
full_name: Bruhn, Clemens
last_name: Bruhn
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Zsolt
full_name: Kelemen, Zsolt
last_name: Kelemen
- first_name: Rudolf
full_name: Pietschnig, Rudolf
last_name: Pietschnig
citation:
ama: Dey S, Kargin D, Höfler MV, et al. Oligo- and polymerization of phospha [2]ferrocenophanes
to one dimensional phosphorus chains with ferrocenylene handles. Polymer.
2022;242:124589.
apa: Dey, S., Kargin, D., Höfler, M. V., Szathmari, B., Bruhn, C., Gutmann, T.,
Kelemen, Z., & Pietschnig, R. (2022). Oligo- and polymerization of phospha
[2]ferrocenophanes to one dimensional phosphorus chains with ferrocenylene handles.
Polymer, 242, 124589.
bibtex: '@article{Dey_Kargin_Höfler_Szathmari_Bruhn_Gutmann_Kelemen_Pietschnig_2022,
title={Oligo- and polymerization of phospha [2]ferrocenophanes to one dimensional
phosphorus chains with ferrocenylene handles}, volume={242}, journal={Polymer},
author={Dey, Subhayan and Kargin, Denis and Höfler, Mark V. and Szathmari, Balazs
and Bruhn, Clemens and Gutmann, Torsten and Kelemen, Zsolt and Pietschnig, Rudolf},
year={2022}, pages={124589} }'
chicago: 'Dey, Subhayan, Denis Kargin, Mark V. Höfler, Balazs Szathmari, Clemens
Bruhn, Torsten Gutmann, Zsolt Kelemen, and Rudolf Pietschnig. “Oligo- and Polymerization
of Phospha [2]Ferrocenophanes to One Dimensional Phosphorus Chains with Ferrocenylene
Handles.” Polymer 242 (2022): 124589.'
ieee: S. Dey et al., “Oligo- and polymerization of phospha [2]ferrocenophanes
to one dimensional phosphorus chains with ferrocenylene handles,” Polymer,
vol. 242, p. 124589, 2022.
mla: Dey, Subhayan, et al. “Oligo- and Polymerization of Phospha [2]Ferrocenophanes
to One Dimensional Phosphorus Chains with Ferrocenylene Handles.” Polymer,
vol. 242, 2022, p. 124589.
short: S. Dey, D. Kargin, M.V. Höfler, B. Szathmari, C. Bruhn, T. Gutmann, Z. Kelemen,
R. Pietschnig, Polymer 242 (2022) 124589.
date_created: 2026-02-07T09:10:38Z
date_updated: 2026-02-17T16:18:36Z
extern: '1'
intvolume: ' 242'
keyword:
- solid-state nmr
- Ansa-ferrocene
- DFT calculations
- Oligophosphine
- Polyphosphane
- Ring-opening polymerization
language:
- iso: eng
page: '124589'
publication: Polymer
status: public
title: Oligo- and polymerization of phospha [2]ferrocenophanes to one dimensional
phosphorus chains with ferrocenylene handles
type: journal_article
user_id: '100715'
volume: 242
year: '2022'
...
---
_id: '29938'
abstract:
- lang: eng
text: Modular solid-state transformers (SSTs) are a promising technology in converting
power from a 10kV three-phase medium voltage to a lower DC-voltage in the range
of 100…400V to provide pure DC power to applications such as electrolyzers for
hydrogen generation, data centers with a DC power distribution and DC micro grids.
Modular SSTs which can be interpreted as modular multilevel converters with an
isolated DC-DC output stage per module, are designed with redundant modules to
increase reliability. Usually, each of the three arms operates independently,
and therefore, only a fixed number of faulty modules can be compensated in each
arm, even if all modules are operational in the remaining two arms. With the proposed
zero-sequence voltage injection, up to 100% more faulty modules can be compensated
in an arm by employing the same hardware. In addition, module power imbalances
are nearly eliminated by utilizing a fundamental frequency zero-sequence voltage.
A dominant 3rd harmonic zero-sequence voltage injection in combination with the
5th, 7th and several higher order harmonics with adaptive (small) amplitudes minimize
the required arm voltages at steady-state. For nominal operation or symmetrical
faults, the proposed technique is equivalent to the well known Min-Max voltage
injection, which already reduces the peak arm voltage by 13.4% compared to a constant
star point potential. A statistical analysis proves, that the expected number
of tolerable faulty modules of the 1MW SST increases by 12% without the need for
additional hardware.
author:
- first_name: Roland
full_name: Unruh, Roland
id: '34289'
last_name: Unruh
- first_name: Jarren
full_name: Lange, Jarren
id: '78801'
last_name: Lange
- first_name: Frank
full_name: Schafmeister, Frank
id: '71291'
last_name: Schafmeister
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
citation:
ama: 'Unruh R, Lange J, Schafmeister F, Böcker J. Adaptive Zero-Sequence Voltage
Injection for Modular Solid-State Transformer to Compensate for Asymmetrical Fault
Conditions. In: 23rd European Conference on Power Electronics and Applications
(EPE’21 ECCE Europe). IEEE; 2021. doi:https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542'
apa: Unruh, R., Lange, J., Schafmeister, F., & Böcker, J. (2021). Adaptive Zero-Sequence
Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical
Fault Conditions. 23rd European Conference on Power Electronics and Applications
(EPE’21 ECCE Europe). 23rd European Conference on Power Electronics and Applications
(EPE’21 ECCE Europe), Ghent, Belgium. https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542
bibtex: '@inproceedings{Unruh_Lange_Schafmeister_Böcker_2021, title={Adaptive Zero-Sequence
Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical
Fault Conditions}, DOI={https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542},
booktitle={23rd European Conference on Power Electronics and Applications (EPE’21
ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland and Lange, Jarren and Schafmeister,
Frank and Böcker, Joachim}, year={2021} }'
chicago: Unruh, Roland, Jarren Lange, Frank Schafmeister, and Joachim Böcker. “Adaptive
Zero-Sequence Voltage Injection for Modular Solid-State Transformer to Compensate
for Asymmetrical Fault Conditions.” In 23rd European Conference on Power Electronics
and Applications (EPE’21 ECCE Europe). IEEE, 2021. https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542.
ieee: 'R. Unruh, J. Lange, F. Schafmeister, and J. Böcker, “Adaptive Zero-Sequence
Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical
Fault Conditions,” presented at the 23rd European Conference on Power Electronics
and Applications (EPE’21 ECCE Europe), Ghent, Belgium, 2021, doi: https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542.'
mla: Unruh, Roland, et al. “Adaptive Zero-Sequence Voltage Injection for Modular
Solid-State Transformer to Compensate for Asymmetrical Fault Conditions.” 23rd
European Conference on Power Electronics and Applications (EPE’21 ECCE Europe),
IEEE, 2021, doi:https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542.
short: 'R. Unruh, J. Lange, F. Schafmeister, J. Böcker, in: 23rd European Conference
on Power Electronics and Applications (EPE’21 ECCE Europe), IEEE, 2021.'
conference:
end_date: 2021-09-10
location: Ghent, Belgium
name: 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE
Europe)
start_date: 2021-09-06
date_created: 2022-02-21T16:31:34Z
date_updated: 2022-09-09T12:01:42Z
department:
- _id: '52'
doi: https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542
keyword:
- Solid-State Transformer
- Zero sequence voltage
- Fault handling strategy
- Power balance control technique
- Three-phase system
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9570542
publication: 23rd European Conference on Power Electronics and Applications (EPE'21
ECCE Europe)
publication_identifier:
isbn:
- 978-9-0758-1537-5
publication_status: published
publisher: IEEE
status: public
title: Adaptive Zero-Sequence Voltage Injection for Modular Solid-State Transformer
to Compensate for Asymmetrical Fault Conditions
type: conference
user_id: '34289'
year: '2021'
...
---
_id: '37274'
abstract:
- lang: eng
text: How are activation programs for the young unemployed implemented? How do street-level
bureaucrats deal with competing rationalities and demands for action? Transition
policies increasingly aim at promoting self-regulation and constructing employable
subjects. Stephan Dahmen explores the practical regulation of biographical transitions
in activation programs for the young unemployed by focusing on the interactive
accomplishment of activation work. The study reveals how the critical tensions
of activation policies are continually re-interpreted and adapted to local contingencies
and describes the various organisational technologies used for creating employable
subjects.
author:
- first_name: Stephan
full_name: Dahmen, Stephan
id: '95659'
last_name: Dahmen
citation:
ama: Dahmen S. Regulating Transitions from School to Work. An Institutional Ethnography
of Activation Work in Action. Bielefeld University Press; 2021. doi:10.14361/9783839457061
apa: Dahmen, S. (2021). Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press. https://doi.org/10.14361/9783839457061
bibtex: '@book{Dahmen_2021, title={Regulating Transitions from School to Work. An
Institutional Ethnography of Activation Work in Action}, DOI={10.14361/9783839457061},
publisher={Bielefeld University Press}, author={Dahmen, Stephan}, year={2021}
}'
chicago: Dahmen, Stephan. Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press, 2021.
https://doi.org/10.14361/9783839457061.
ieee: S. Dahmen, Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press, 2021.
mla: Dahmen, Stephan. Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press, 2021,
doi:10.14361/9783839457061.
short: S. Dahmen, Regulating Transitions from School to Work. An Institutional Ethnography
of Activation Work in Action, Bielefeld University Press, 2021.
date_created: 2023-01-18T10:18:09Z
date_updated: 2023-01-18T10:18:54Z
department:
- _id: '723'
- _id: '724'
- _id: '36'
doi: 10.14361/9783839457061
keyword:
- Youth
- Welfare State
- Transitions
- Human Service Organizations
- Institutional Ethnography
- Activation
- Sociology of Conventions
- Work
- Education
- Educational Research
- Sociology of Education
- Social Pedagogy
- History of Education
- Bielefeld University Press
language:
- iso: eng
page: '312'
publisher: Bielefeld University Press
status: public
title: Regulating Transitions from School to Work. An Institutional Ethnography of
Activation Work in Action
type: book
user_id: '48187'
year: '2021'
...
---
_id: '37273'
abstract:
- lang: eng
text: How are activation programs for the young unemployed implemented? How do street-level
bureaucrats deal with competing rationalities and demands for action? Transition
policies increasingly aim at promoting self-regulation and constructing employable
subjects. Stephan Dahmen explores the practical regulation of biographical transitions
in activation programs for the young unemployed by focusing on the interactive
accomplishment of activation work. The study reveals how the critical tensions
of activation policies are continually re-interpreted and adapted to local contingencies
and describes the various organisational technologies used for creating employable
subjects.
author:
- first_name: Stephan
full_name: Dahmen, Stephan
last_name: Dahmen
citation:
ama: Dahmen S. Regulating Transitions from School to Work. An Institutional Ethnography
of Activation Work in Action. Bielefeld University Press; 2021. doi:10.14361/9783839457061
apa: Dahmen, S. (2021). Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press. https://doi.org/10.14361/9783839457061
bibtex: '@book{Dahmen_2021, title={Regulating Transitions from School to Work. An
Institutional Ethnography of Activation Work in Action}, DOI={10.14361/9783839457061},
publisher={Bielefeld University Press}, author={Dahmen, Stephan}, year={2021}
}'
chicago: Dahmen, Stephan. Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press, 2021.
https://doi.org/10.14361/9783839457061.
ieee: S. Dahmen, Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press, 2021.
mla: Dahmen, Stephan. Regulating Transitions from School to Work. An Institutional
Ethnography of Activation Work in Action. Bielefeld University Press, 2021,
doi:10.14361/9783839457061.
short: S. Dahmen, Regulating Transitions from School to Work. An Institutional Ethnography
of Activation Work in Action, Bielefeld University Press, 2021.
date_created: 2023-01-18T10:14:30Z
date_updated: 2023-01-18T10:16:56Z
department:
- _id: '723'
- _id: '724'
doi: 10.14361/9783839457061
keyword:
- Youth
- Welfare State
- Transitions
- Human Service Organizations
- Institutional Ethnography
- Activation
- Sociology of Conventions
- Work
- Education
- Educational Research
- Sociology of Education
- Social Pedagogy
- History of Education
- Bielefeld University Press
language:
- iso: eng
page: '312'
publisher: Bielefeld University Press
status: public
title: Regulating Transitions from School to Work. An Institutional Ethnography of
Activation Work in Action
type: book
user_id: '48187'
year: '2021'
...