102 research outputs found
Value Stream Mapping and Process Mining: A Lean Method Supported by Data Analytics
The analysis and further the reorganization of an order-production is a typical scope of application of a value stream mapping. Value stream mapping is a lean-management method to map the current state of a series of processes that are necessary to manufacture a product or provide a service. The ever-increasing digitalization emphasizes the importance of the information flow. Besides the material flow, the information flow is the second focus of value stream mapping. It is needed to get valuable insights into the production process by applying state-of-the-art data analytics methods. Process Mining is a possible method to analyse (business) process and process sequences based on event logs. This paper illustrates a method of combining conventional value stream mapping and Process Mining. While value stream mapping shows the material and information flow as the people think it is, Process Mining shows how they are, based on the data fingerprint. The comparison of the two outcomes allows conclusions for the following value stream design with a special focus on the use of data for Industry 4.0 applications. The application of both methods to an order-production enables to present results and compare both as well as present advantages and disadvantages
Controlled vortex core switching in a magnetic nanodisk by a rotating field
The switching process of the vortex core in a Permalloy nanodisk affected by
a rotating magnetic field is studied theoretically. A detailed description of
magnetization dynamics is obtained by micromagnetic simulations.Comment: REVTeX, 5 pages, 5 figure
Vortex motion in a finite-size easy-plane ferromagnet and application to a nanodot
We study the motion of a non-planar vortex in a circular easy-plane
ferromagnet, which imitates a magnetic nanodot. Analysis was done using
numerical simulations and a new collective variable theory which includes the
coupling of Goldstone-like mode with the vortex center. Without magnetic field
the vortex follows a spiral orbit which we calculate. When a rotating in-plane
magnetic field is included, the vortex tends to a stable limit cycle which
exists in a significant range of field amplitude B and frequency for a
given system size L. For a fixed , the radius R of the orbital motion
is proportional to L while the orbital frequency varies as 1/L and is
significantly smaller than . Since the limit cycle is caused by the
interplay between the magnetization and the vortex motion, the internal mode is
essential in the collective variable theory which then gives the correct
estimate and dependency for the orbit radius . Using this
simple theory we indicate how an ac magnetic field can be used to control
vortices observed in real magnetic nanodots.Comment: 15 pages (RevTeX), 14 figures (eps
Effective anisotropy of thin nanomagnets: beyond the surface anisotropy approach
We study the effective anisotropy induced in thin nanomagnets by the nonlocal
demagnetization field (dipole-dipole interaction). Assuming a magnetization
independent of the thickness coordinate, we reduce the energy to an
inhomogeneneous onsite anisotropy. Vortex solutions exist and are ground states
for this model. We illustrate our approach for a disk and a square geometry. In
particular, we obtain good agreement between spin-lattice simulations with this
effective anisotropy and micromagnetic simulations.Comment: ReVTeX, 14 pages, 6 figure
Magnetic vortex as a ground state for micron-scale antiferromagnetic samples
Here we consider micron-sized samples with any axisymmetric body shape and
made with a canted antiferromagnet, like hematite or iron borate. We find that
its ground state can be a magnetic vortex with a topologically non-trivial
distribution of the sublattice magnetization and planar coreless
vortex-like structure for the net magnetization . For
antiferromagnetic samples in the vortex state, in addition to low-frequency
modes, we find high-frequency modes with frequencies over the range of hundreds
of gigahertz, including a mode localized in a region of radius 30--40 nm
near the vortex core.Comment: 20 pages, 1 figur
Switching phenomena in magnetic vortex dynamics
A magnetic nanoparticle in a vortex state is a promising candidate for the
information storage. One bit of information corresponds to the upward or
downward magnetization of the vortex core (vortex polarity). Generic properties
of the vortex polarity switching are insensitive of the way how the vortex
dynamics was excited: by an AC magnetic field, or by an electrical current. We
study theoretically the switching process and describe in detail its mechanism,
which involves the creation and annihilation of an intermediate
vortex-antivortex pair.Comment: REVTeX, 8 pages, 2 figures; to appear in a special issue of Low
Temperature Physics in memory of A.M.Kosevic
Hazard characterization of Alternaria toxins to identify data gaps and improve risk assessment for human health
Fungi of the genus Alternaria are ubiquitous plant pathogens and saprophytes which are able to grow under varying temperature and moisture conditions as well as on a large range of substrates. A spectrum of structurally diverse secondary metabolites with toxic potential has been identified, but occurrence and relative proportion of the different metabolites in complex mixtures depend on strain, substrate, and growth conditions. This review compiles the available knowledge on hazard identification and characterization of Alternaria toxins. Alternariol (AOH), its monomethylether AME and the perylene quinones altertoxin I (ATX-I), ATX-II, ATX-III, alterperylenol (ALP), and stemphyltoxin III (STTX-III) showed in vitro genotoxic and mutagenic properties. Of all identified Alternaria toxins, the epoxide-bearing analogs ATX-II, ATX-III, and STTX-III show the highest cytotoxic, genotoxic, and mutagenic potential in vitro. Under hormone-sensitive conditions, AOH and AME act as moderate xenoestrogens, but in silico modeling predicts further Alternaria toxins as potential estrogenic factors. Recent studies indicate also an immunosuppressive role of AOH and ATX-II; however, no data are available for the majority of Alternaria toxins. Overall, hazard characterization of Alternaria toxins focused, so far, primarily on the commercially available dibenzo-α-pyrones AOH and AME and tenuazonic acid (TeA). Limited data sets are available for altersetin (ALS), altenuene (ALT), and tentoxin (TEN). The occurrence and toxicological relevance of perylene quinone-based Alternaria toxins still remain to be fully elucidated. We identified data gaps on hazard identification and characterization crucial to improve risk assessment of Alternaria mycotoxins for consumers and occupationally exposed workers.The European Partnership for the Assessment of Risks from Chemicals has received funding from the European Union’s Horizon Europe research and innovation program under Grant Agreement No 101057014 and has received co-funding of the authors’ institutions. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.info:eu-repo/semantics/publishedVersio
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