Computing rotation and self-linking numbers in contact surgery diagrams

We give an explicit formula to compute the rotation number of a nullhomologous Legendrian knot in contact (1/n)-surgery diagrams along Legendrian links and obtain a corresponding result for the self-linking number of transverse knots. Moreover, we extend the formula by Ding-Geiges-Stipsicz for computing the d3-invariant to (1/n)-surgeries.Comment: 19 pages, 6 figures; V2: Added the section on the d3-invariant and fixed a few misprints; V3: Minor corrections and clarifications; V4: Added a missing "n" in the formula for computing the Euler class of the contact structure in Theorem 5.

Handle homology of manifolds

We give an entirely geometric proof, without recourse to cellular homology, of the fact that partial derivative(2) = 0 in the chain complex defined by a handle decomposition of a given manifold. Topological invariance of the resulting 'handle homology' is a consequence of Cerf theory. (C) 2019 Elsevier B.V. All rights reserved

Regionale Unterschiede der qualitativen Beschaeftigungsstruktur in den Sektoren des Verarbeitenden Gewerbes in Niedersachsen

SIGLEIAB-90-ONSO-204201 AE 959 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Parallelisability of 3-manifolds via surgery

We present two proofs that all closed, orientable 3-manifolds are parallelisable. Both are based on the Lickorish-Wallace surgery presentation; one proof uses a refinement of this presentation due to Kaplan and some basic contact geometry. This complements a recent paper by Benedetti-Lisca. (C) 2019 Elsevier GmbH. All rights reserved

Determination of the Bonding Strength of Finger Joints Using a New Test Specimen Geometry

In this study, a specimen geometry for testing finger joints was developed using finite element simulation and proofed by experimental testing. Six different wood species and three adhesives were used for finger-jointing specimens. With the test specimen geometry, the bonding strength of the finger joints was determined without the usual self-locking of the joint. Under load, the test specimen geometry introduces maximum stress at the beginning of the bond line (adhesive zone). However, the test specimen geometry does not generate a symmetric stress state. The main difficulty here is the flank angle of the finger joint geometry. The wood species and adhesives significantly influenced the performance of the finger joints

Determination of the Bonding Strength of Finger Joints Using a New Test Specimen Geometry

In this study, a specimen geometry for testing finger joints was developed using finite element simulation and proofed by experimental testing. Six different wood species and three adhesives were used for finger-jointing specimens. With the test specimen geometry, the bonding strength of the finger joints was determined without the usual self-locking of the joint. Under load, the test specimen geometry introduces maximum stress at the beginning of the bond line (adhesive zone). However, the test specimen geometry does not generate a symmetric stress state. The main difficulty here is the flank angle of the finger joint geometry. The wood species and adhesives significantly influenced the performance of the finger joints

Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content