136 research outputs found
Symplectic toric stratified spaces with isolated singularities
We provide a classification of two types of toric objects: symplectic toric cones and symplectic toric stratified spaces with isolated singularities. Both types of object are classified via orbital moment map and a second degree cohomology class.
As symplectic toric stratified spaces with isolated singularities are locally modeled on symplectic toric cones, we first focus on classifying symplectic toric cones. We show that symplectic toric cones have a certain type of map (called homogeneous unimodular local embeddings) as orbital moment maps. Conversely, every homogeneous unimodular local embedding has a symplectic toric cone for which it is an orbital moment map. We classify the symplectic toric cones with the same orbital moment map by showing that their isomorphism classes are in bijective correspondence with the first Chern classes of principal G-bundles over W. This generalizes Lerman’s classification of compact connected contact toric manifolds.
Symplectic toric stratified spaces with isolated singularities are spaces with neighborhoods of singularities modeled on symplectic cones. We first show their quotients W are space stratified by manifolds with corners and their moment maps are a particular type of map called stratified unimodular local embeddings. Every stratified unimodular local embedding is the orbital moment map of a symplectic toric stratified space. Finally, we show that, for any stratified unimodular local embedding, the isomorphism classes of symplectic toric stratified spaces with isolated singularities with a given orbital moment map are in bijective correspondence with a collection of cohomology classes dependent on the topology of W. This generalizes Burns, Guillemin, and Lerman’s classification of the compact connected symplectic toric stratified spaces with isolated singularities
Digitalization of musculoskeletal risk assessment in a robotic-assisted assembly workstation
The ergonomic assessment of adopted working postures is essential for avoiding musculoskeletal risk factors in manufacturing contexts. Several observational methods based on external analyst observations are available; however, they are relatively subjective and suffer low repeatability. Over the past decade, the digitalization of this assessment has received high research interest. Robotic applications have the potential to lighten workers’ workload and improve working conditions. Therefore, this work presents a musculoskeletal risk assessment before and after robotic implementation in an assembly workstation. We also emphasize the importance of using novel and non-intrusive technologies for musculoskeletal risk assessment. A kinematic study was conducted using inertial motion units (IMU) in a convenience sample of two workers during their normal performance of assembly work cycles. The musculoskeletal risk was estimated according to a semi-automated solution, called the Rapid Upper Limb Assessment (RULA) report. Based on previous musculoskeletal problems reported by the company, the assessment centered on the kinematic analysis of functional wrist movements (flexion/extension, ulnar/radial deviation, and pronation/supination). The results of the RULA report showed a reduction in musculoskeletal risk using robotic-assisted assembly. Regarding the kinematic analysis of the wrist during robotic-assisted tasks, a significant posture improvement of 20–45% was registered (considering the angular deviations relative to the neutral wrist position). The results obtained by direct measurements simultaneously reflect the workload and individual characteristics. The current study highlights the importance of an in-field instrumented assessment of musculoskeletal risk and the limitations of the system applied (e.g., unsuitable for tracking the motion of small joints, such as the fingers).This work was supported by NORTE-06-3559-FSE-000018, integrated in the invitation
NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the
Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF). This work was also supported by FCT–Fundação
para a CiĂŞncia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020
Redox properties of the iron-sulfur clusters in activated Fe-hydrogenase from Desulfovibrio vulgaris (Hildenborough)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65750/1/j.1432-1033.1992.tb17261.x.pd
mRNA changes during imaginal determination of the epidermal cells in the pupa ofGalleria mellonella L
Purification and biochemical characterization of a putative [6Fe-6S] prismane cluster containing protein from Desulfovibrio vulgaris (Hildenborough).
Sociaal-psychologische effecten van ICT's en hun beleidsimplicaties [Social-psychological effects of ICTs and their policy implications].
Compared analysis of sulfur, nitrogen and heavy metal compounds of solid recovered fuels air gasification at pilot scale
Air gasification of Solid Recovered Fuels (SRF) from wood, tire, plastics and sewage sludge has been performed in a pilot fixed bed reactor. As wastes contain pollutants precursors, it is of great interest regarding technical and environmental aspects to study their behavior in air gasification. Five fuels have been studied: Poplar, SRF wood, and three different mixtures of SRF wood and 20% of either tire (mix A), or plastics (mix B) or sewage sludge (mix C). After confirming their capacity of substituting raw wood in order to produce synthetic gas (syngas), emissions analyses have been performed on syngas, condensable matter and remaining char. A focus on sulfur, nitrogen and heavy metals brought to light differences and similarities between different SRF and raw wood
Comparative analysis of wood and solid recovered fuels gasification in a downdraft fixed bed reactor
International audienc
In-vitro-Mikrokerntest in der Routinepruefung auf genotoxische Eigenschaften: Teilprojekt 3: Validierung einer Standardmethodenbeschreibung Abschlussbericht
Available from TIB Hannover: F00B242 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman
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