Institution
Technische Universität Darmstadt
Education•Darmstadt, Germany•
About: Technische Universität Darmstadt is a education organization based out in Darmstadt, Germany. It is known for research contribution in the topics: Neutron & Finite element method. The organization has 17316 authors who have published 40619 publications receiving 937916 citations. The organization is also known as: Darmstadt University of Technology & University of Darmstadt.
Topics: Neutron, Finite element method, Laser, Catalysis, Thin film
Papers published on a yearly basis
Papers
More filters
••
TL;DR: A self-seeding technique is reported that enables the generation of arrays of orientation-correlated polymer crystals of uniform size and shape with their orientation inherited from an initial single crystal, attributing this unique behaviour of polymers to the coexistence of variable fold lengths in metastable crystalline lamellae.
Abstract: In general, when a crystal is molten, all molecules forget about their mutual correlations and long-range order is lost. Thus, a regrown crystal does not inherit any features from an initially present crystal. Such is true for materials exhibiting a well-defined melting point. However, polymer crystallites have a wide range of melting temperatures, enabling paradoxical phenomena such as the coexistence of melting and crystallization. Here, we report a self-seeding technique that enables the generation of arrays of orientation-correlated polymer crystals of uniform size and shape ('clones') with their orientation inherited from an initial single crystal. Moreover, the number density and locations of these cloned crystals can to some extent be predetermined through the thermal history of the starting crystal. We attribute this unique behaviour of polymers to the coexistence of variable fold lengths in metastable crystalline lamellae, typical for ordering of complex chain-like molecules.
220 citations
••
TL;DR: In this paper, the basic equations for second-order generalized beam theory are outlined, and solutions for pin-ended supports are presented, demonstrating the coupling effect by modes and by loads.
Abstract: First-order generalized beam theory describes the behaviour of prismatic structures by ordinary uncoupled differential equations, using deformation functions for bending, torsion and distortion. In second-order theory, the differential equations are coupled by the effect of deviating forces. The basic equations for second-order generalized beam theory are outlined. Solutions for pin-ended supports are presented, demonstrating the coupling effect by modes and by loads. In the different ranges of length, the individual modes are sufficient approximations for the critical load. The application to a thin-walled bar with C-section under eccentric normal force demonstrates the quality of the single-mode compared to the exact solution.
220 citations
••
TL;DR: In this paper, the energy spectra of protons and light nuclei produced by the interaction of $4]-mathrm{He}$ and $20]-mathm{Ne}$ projectiles with Al and U targets have been investigated at incident energies ranging from 0.25 to 2.1 GeV per nucleon.
Abstract: The energy spectra of protons and light nuclei produced by the interaction of $^{4}\mathrm{He}$ and $^{20}\mathrm{Ne}$ projectiles with Al and U targets have been investigated at incident energies ranging from 0.25 to 2.1 GeV per nucleon. Single fragment inclusive spectra have been obtained at angles between 25\ifmmode^\circ\else\textdegree\fi{} and 150\ifmmode^\circ\else\textdegree\fi{}, in the energy range from 30 to 150 MeV/nucleon. The multiplicity of intermediate and high energy charged particles was determined in coincidence with the measured fragments. In a separate study, fragment spectra were obtained in the evaporation energy range from $^{12}\mathrm{C}$ and $^{20}\mathrm{Ne}$ bombardment of uranium. We observe structureless, exponentially decaying spectra throughout the range of studied fragment masses. There is evidence for two major classes of fragments; one with emission at intermediate temperature from a system moving slowly in the lab frame, and the other with high temperature emission from a system propagating at a velocity intermediate between target and projectile. The high energy proton spectra are fairly well reproduced by a nuclear fireball model based on simple geometrical, kinematical, and statistical assumptions. Light cluster emission is also discussed in the framework of statistical models.NUCLEAR REACTIONS $\mathrm{U}(^{20}\mathrm{Ne},X)$, $E=250$ MeV/nucl.; $U(^{20}\mathrm{Ne},X)$, $U(\ensuremath{\alpha},X)$ $E=400$ MeV/nucl.; $\mathrm{U}(^{20}\mathrm{Ne},X)$, $\mathrm{Al}(^{20}\mathrm{Ne},X)$, $E=2.1$ GeV/nucl.; measured $\ensuremath{\sigma}(E,\ensuremath{\theta})$, $X=p,d,t,^{3}\mathrm{He},^{4}\mathrm{He}$. $\mathrm{U}(^{20}\mathrm{Ne},X)$, $U(\ensuremath{\alpha},X)$, $E=400$ MeV/nucl.; $U(^{20}\mathrm{Ne},X)$, $E=2.1$ GeV/nucl.; measured $\ensuremath{\sigma}(E,\ensuremath{\theta})$, Li to O. $\mathrm{U}(^{20}\mathrm{Ne},X)$, $U(^{12}\mathrm{C},X)$, $E=2.1$ GeV/nucl.; measured $\ensuremath{\sigma}(E,90\ifmmode^\circ\else\textdegree\fi{})$, $^{4}\mathrm{He}$ to B. Nuclear fireballs, coalescence, thermodynamics of light nuclei production.
220 citations
••
TL;DR: In this paper, the authors used piezoresponse force microscopy (PFM) to study the nanoscale electromechanical behavior of lead-free piezoceramics.
Abstract: Piezoresponse force microscopy (PFM) is used to afford insight into the nanoscale electromechanical behavior of lead-free piezoceramics. Materials based on Bi1/2Na1/2TiO3 exhibit high strains mediated by a field-induced phase transition. Using the band excitation technique the initial domain morphology, the poling behavior, the switching behavior, and the time-dependent phase stability in the pseudo-ternary system (1–x)(0.94Bi1/2Na1/2TiO3-0.06BaTiO3)-xK0.5Na0.5NbO3 (0 = 3 mol%. This PFM study provides a novel perspective on the interplay between macroscopic and nanoscopic material properties in bulk lead-free piezoceramics.
219 citations
••
TL;DR: A parameter estimation technique for fault detection on brushless DC motors, based on a mathematical model of the process, which provides information about the electrical resistance and the back-EMF constant as well as about the mechanical parameters.
Abstract: In comparison to classical DC motors, brushless DC motors are very reliable, Nevertheless, they can also fail, caused by, e.g., overheating or mechanical wear. This paper proposes a parameter estimation technique for fault detection on this type of motor. Simply by measuring the motor's input and output signals, its parameters can be estimated. This method is based on a mathematical model of the process. In the presented work, a square-wave motor is considered. An appropriate model is derived. To be able to implement the method also on low-cost microcontroller-based control units, only the power inverter supply voltage, DC current, and the motor's angular velocity have to be measured. The parameter estimation technique provides information about the electrical resistance and the back-EMF constant as well as about the mechanical parameters. Comparing the nominal with the computed parameters, faults can be detected. The approach might be applied to both end-of-line and online fault detection. Results for simulated data demonstrate the capabilities of the proposed procedure. Finally, a real-world application-an actuation system with a brushless DC motor mounted to a gearbox-is given.
219 citations
Authors
Showing all 17627 results
Name | H-index | Papers | Citations |
---|---|---|---|
Yang Gao | 168 | 2047 | 146301 |
Herbert A. Simon | 157 | 745 | 194597 |
Stephen Boyd | 138 | 822 | 151205 |
Jun Chen | 136 | 1856 | 77368 |
Harold A. Mooney | 135 | 450 | 100404 |
Bernt Schiele | 130 | 568 | 70032 |
Sascha Mehlhase | 126 | 858 | 70601 |
Yuri S. Kivshar | 126 | 1845 | 79415 |
Michael Wagner | 124 | 351 | 54251 |
Wolf Singer | 124 | 580 | 72591 |
Tasawar Hayat | 116 | 2364 | 84041 |
Edouard Boos | 116 | 757 | 64488 |
Martin Knapp | 106 | 1067 | 48518 |
T. Kuhl | 101 | 761 | 40812 |
Peter Braun-Munzinger | 100 | 527 | 34108 |