2,427 research outputs found
Topography Measurement for Monitoring Manufacturing Processes in Harsh Conditions
High precision manufacturing, e.g. milling and grinding, which have manufacturing tolerances in the range of <10 μm require microscopic measurement techniques for the inspection of the manufactured components. These measurement techniques are very sensitive to cooling liquids and lubricants which are essential for many manufacturing processes. Therefore, the measurement of the components is usually conducted in separate and clean laboratories and not directly in the manufacturing machine. This approach has some major drawbacks, e.g. high time consumption and no possibility for online process monitoring. In this article, a novel concept for the integration of high precision optical topography measurement systems into the manufacturing machine is introduced and compared to other concepts. The introduced concept uses a reservoir with cooling liquid in which the measurement object is immersed during the measurement. Thereby, measurement disturbance by splashing cooling liquids and lubricants can effectively be avoided.BMBF/03V047
Synergy of lidar and passive remote sensor data for retrieving profiles of microphysical properties of non-spherical particles
© The Authors, published by EDP Sciences, 2018. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).In this study we explore how the combination of 3 backscatter and 2 extinction lidar data with data that can be collected with ground-based and space-borne passive remote sensors, e.g. phase function coefficients which can be derived at various measurement wavelengths and scattering angles can result in improved profiles of particle microphysical properties. The algorithm is based on a light-scattering model that uses a mixture of spheres and randomly oriented spheroids.Peer reviewe
Practisches Handbuch des Ackerbaues, vorzugsweise für die Ostseeländer Russlands bearbeitet
http://tartu.ester.ee/record=b2432737~S1*es
Practisches Handbuch des Ackerbaues, vorzugsweise für die Ostseeländer Russlands bearbeitet
http://tartu.ester.ee/record=b2432740~S1*es
Mittheilungen und Erfahrungen aus einer Knechtswirthschaft
http://www.ester.ee/record=b1807732*es
Practisches Handbuch der Landwirtschaft, vorzugsweise für die Ostseeländer Russlands bearbeitet; oder : gründliche Anleitung zum Getreide-, Kartoffel- und Futterbau, zur Behandlung und Anwendung des Düngers und zur Urbarmachung von Wäldern und Wüstungen; mit einem Anhange über diejenigen Leistungen bei den landwirtschaftlichen Hauptarbeiten, die ein Hofsknecht oder ein Fröhner mit Anspann oder zu Fuss, - sowohl mit ausländischem, als hiesigem Arbeitsgeräth - in einer bestimmten Zeit verrichten kann
http://tartu.ester.ee/record=b2432741~S1*es
Revealing the co-action of viscous and multistability hysteresis in an adhesive, nominally flat punch: A combined numerical and experimental study
Viscoelasticity is well known to cause significant hysteresis of crack
closure and opening when an elastomer is brought in and out of contact with a
flat, rigid, adhesive counterface. A separate origin of adhesive hysteresis is
small-scale, elastic multistability. Here, we study a system in which both
mechanisms act concurrently. Specifically, we compare the simulated and
experimentally measured time evolution of the interfacial force and the real
contact area between a soft elastomer and a rigid, flat punch, to which
small-scale, single-sinusoidal roughness is added. To this end, we further the
Green's function molecular dynamics method and extend recently developed
imaging techniques to elucidate the rate- and preload-dependence of the
pull-off process. Our results reveal that hysteresis is much enhanced when the
saddle points of the topography come into contact, which, however, is impeded
by viscoelastic forces and may require sufficiently large preloads. A similar
coaction of viscous- and multistability effects is expected to occur in
macroscopic polymer contacts and to be relevant, e.g., for pressure-sensitive
adhesives and modern adhesive gripping devices.Comment: 24 pages, 12 figures. Published in the Journal of the Mechanics and
Physics of Solids. Conceptualization: All authors. Writing original draft:
CM, MHM, MS. Experimental methodology and investigation: MS, supervision
experiments: RH+EA. Numerical methodology: CM, MHM, simulations and data
analysis: CM, supervision simulations: MH
Recommended from our members
Revealing the co-action of viscous and multistability hysteresis in an adhesive, nominally flat punch: A combined numerical and experimental study
Viscoelasticity is well known to cause a significant hysteresis of crack closure and opening when an elastomer is brought in and out of contact with a flat, rigid counterface. In contrast, the idea that adhesive hysteresis can also result under quasi-static driving due to small-scale, elastic multistability is relatively new. Here, we study a system in which both mechanisms act concurrently. Specifically, we compare the simulated and experimentally measured time evolution of the interfacial force and the real contact area between a soft elastomer and a rigid, flat punch, to which small-scale, single-sinusoidal roughness is added. To this end, we further the Green's function molecular dynamics method and extend recently developed imaging techniques to elucidate the rate- and preload-dependence of the pull-off process. Our results reveal that hysteresis is much enhanced when the saddle points of the topography come into contact, which, however, is impeded by viscoelastic forces and may require sufficiently large preloads. A similar coaction of viscous- and multistability effects is expected to occur in macroscopic polymer contacts and be relevant, e.g., for pressure-sensitive adhesives and modern adhesive gripping devices
Brain Edema Formation and Functional Outcome After Surgical Decompression in Murine Closed Head Injury Are Modulated by Acetazolamide Administration
Acetazolamide (ACZ), carbonic anhydrase inhibitor, has been successfully applied in
several neurosurgical conditions for diagnostic or therapeutic purposes. Furthermore,
neuroprotective and anti-edematous properties of ACZ have been postulated. However,
its use in traumatic brain injury (TBI) is limited, since ACZ-caused vasodilatation
according to the Monro-Kellie doctrine may lead to increased intracranial blood
volume / raise of intracranial pressure. We hypothesized that these negative effects
of ACZ will be reduced or prevented, if the drug is administered after already
performed decompression. To test this hypothesis, we used a mouse model of closed
head injury (CHI) and decompressive craniectomy (DC). Mice were assigned into
following experimental groups: sham, DC, CHI, CHI+ACZ, CHI+DC, and CHI+DC+ACZ
(n = 8 each group). 1d and 3d post injury, the neurological function was assessed
according to Neurological Severity Score (NSS) and Beam Balance Score (BBS). At
the same time points, brain edema was quantified by MRI investigations. Functional
impairment and edema volume were compared between groups and over time.
Among the animals without skull decompression, the group additionally treated with
acetazolamide demonstrated the most severe functional impairment. This pattern was
reversed among the mice with decompressive craniectomy: CHI+DC treated but not
CHI+DC+ACZ treated animals showed a significant neurological deficit. Accordingly,
radiological assessment revealed most severe edema formation in the CHI+DC group
while in CHI+DC+ACZ animals, volume of brain edema did not differ from DC-only
animals. In our CHI model, the response to acetazolamide treatment varies between animals with decompressive craniectomy and those without surgical treatment. Opening
the cranial vault potentially creates an opportunity for acetazolamide to exert its beneficial
effects while vasodilatation-related risks are attenuated. Therefore, we recommend
further exploration of this potentially beneficial drug in translational research projects
Manufacturing of embedded multimode waveguides by reactive lamination of cyclic olefin polymer and polymethylmethacrylate
We demonstrate the manufacturing of embedded multimode optical waveguides through linking of polymethylmethacrylate (PMMA) foils and cyclic olefin polymer (COP) filaments based on a lamination process. Since the two polymeric materials cannot be fused together through interdiffusion of polymer chains, we utilize a reactive lamination agent based on PMMA copolymers containing photoreactive 2-acryloyloxyanthraquinone units, which allows the creation of monolithic PMMA-COP substrates through C-H insertion reactions across the interface between the two materials. We elucidate the lamination process and evaluate the chemical link between filament and foils by carrying out extraction tests with a custom-built tensile testing machine. We also show attenuation measurements of the manufactured waveguides for different manufacturing parameters. The lamination process is in particular suited for large-scale and low-cost fabrication of board-level devices with optical waveguides or other micro-optical structures, e.g., optofluidic devices. © 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).DFG/SFB/TRR 12
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