Parameter Identification of Pressure Sensors by Static and Dynamic Measurements

Fast identification methods of pressure sensors are investigated. With regard to a complete accurate sensor parameter identification two different measurement methods are combined. The approach consists on one hand in performing static measurements - an applied pressure results in a membrane deformation measured interferometrically and the corresponding output voltage. On the other hand optical measurements of the modal responses of the sensor membranes are performed. This information is used in an inverse identification algorithm to identify geometrical and material parameters based on a FE model. The number of parameters to be identified is thereby generally limited only by the number of measurable modal frequencies. A quantitative evaluation of the identification results permits furthermore the classification of processing errors like etching errors. Algorithms and identification results for membrane thickness, intrinsic stress and output voltage will be discussed in this contribution on the basis of the parameter identification of relative pressure sensors.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Rheological Model for Wood

Wood as the most important natural and renewable building material plays an important role in the construction sector. Nevertheless, its hygroscopic character basically affects all related mechanical properties leading to degradation of material stiffness and strength over the service life. Accordingly, to attain reliable design of the timber structures, the influence of moisture evolution and the role of time- and moisture-dependent behaviors have to be taken into account. For this purpose, in the current study a 3D orthotropic elasto-plastic, visco-elastic, mechano-sorptive constitutive model for wood, with all material constants being defined as a function of moisture content, is presented. The corresponding numerical integration approach, with additive decomposition of the total strain is developed and implemented within the framework of the finite element method (FEM). Moreover to preserve a quadratic rate of asymptotic convergence the consistent tangent operator for the whole model is derived. Functionality and capability of the presented material model are evaluated by performing several numerical verification simulations of wood components under different combinations of mechanical loading and moisture variation. Additionally, the flexibility and universality of the introduced model to predict the mechanical behavior of different species are demonstrated by the analysis of a hybrid wood element. Furthermore, the proposed numerical approach is validated by comparisons of computational evaluations with experimental results.Comment: 37 pages, 13 figures, 10 table

Functional renormalization group analysis of Dzyaloshinsky Moriya and Heisenberg spin interactions on the kagome lattice

We investigate the effects of Dzyaloshinsky-Moriya (DM) interactions on the frustrated $J_1$-$J_2$ kagome-Heisenberg model using the pseudo-fermion functional-renormalization-group (PFFRG) technique. In order to treat the off-diagonal nature of DM interactions, we develop an extended PFFRG scheme. We benchmark this approach in parameter regimes that have previously been studied with other methods and find good agreement of the magnetic phase diagram. Particularly, finite DM interactions are found to stabilize all types of non-collinear magnetic orders of the $J_1$-$J_2$ Heisenberg model ($\mathbf{q}=0$, $\sqrt{3}\times\sqrt{3}$, and cuboc orders) and shrink the extents of magnetically disordered phases. We discuss our results in the light of the mineral {\it herbertsmithite} which has been experimentally predicted to host a quantum spin liquid at low temperatures. Our PFFRG data indicates that this material lies in close proximity to a quantum critical point. In parts of the experimentally relevant parameter regime for {\it herbertsmithite}, the spin-correlation profile is found to be in good qualitative agreement with recent inelastic-neutron-scattering data

Integration of new experiments into the reflood map

The reflood map, developed in the last decade, was designed as a tool to focus on preventive and mitigative measures to prevent severe core damage scenarios and to identify research areas. In the meanwhile, additional experiments were performed and their data are available, so that an update seems necessary. For homogeneous particulate debris configurations, several experimental programs shed light on coolability. For the transition from in-core early phase to in-core late phase i.e. the loss of the rod like geometry, experimental database is still rather scarce due to the difficulty to describe the state of the core components and the fluid adequately. According to the new insight, an update of the database and the reflood map is discussed, also with respect to assess available grace times

Characterization of quantum spin liquids and their spinon band structures via functional renormalization

We combine the pseudofermion functional renormalization group PFFRG method with a self consistent Fock like mean field scheme to calculate low energy effective theories for emergent spinon excitations in spin 1 2 quantum spin liquids. Using effective spin interactions from PFFRG as an input for the Fock equation and allowing for the most general types of free spinon Ansätze as classified by the projective symmetry group PSG method, we are able to systematically determine spinon band structures for spin liquid candidate systems beyond mean field theory. We apply this approach to the antiferromagnetic J1 amp; 8722;J2 Heisenberg model on the square lattice and to the antiferromagnetic nearest neighbor Heisenberg model on the kagome lattice. For the J1 amp; 8722;J2 model, we find that in the regime of maximal frustration a SU 2 pi flux state with Dirac spinons yields the largest mean field amplitudes. For the kagome model, we identify a gapless Z2 spin liquid with a small circular spinon Fermi surface and approximate Dirac cones at low but finite energie

The c- Jun N-terminal kinase JNK participates in cytokine- and isolation stress-induced rat pancreatic islet apoptosis

Aims/hypothesis: The protocols used for the preparation of human pancreatic islets immediately induce a sustained and massive activation of the c-Jun-N-terminal kinase (JNK). JNK, which participates in apoptosis of insulin-secreting cells, is activated by mechanical stresses, as well as by exposure to pro-inflammatory cytokines. Here, we investigated whether the delivery of a protease-resistant JNK inhibitory peptide (D-JNKI) through a protein transduction system during pancreatic digestion might impair JNK signalling throughout the transplantation procedure. Methods: Rat pancreases were treated with D-JNKI through the pancreatic duct and cells then isolated by enzymatic digestion. Protein extracts were prepared to determine JNK activity by kinase assays and total RNA was extracted to measure gene expressions by a Light-Cycler technique. Cell apoptosis rate was determined by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay and by scoring cells displaying pycnotic nuclei. Results: Our data establish that the peptide transduction system used here efficiently transfects islets, allowing for stable in vivo (up to 2days) transfection of human islets transplanted under the kidney capsule. Further, D-JNKI decreases intracellular JNK signalling during isolation and following cytokine exposure in both human and rat islets, as measured by kinase assays and reduced c-fos expression; D-JNKI also confers protection against apoptosis induced during the rat islet preparation and subsequent to IL-1β exposure. Conclusions/interpretation: JNK signalling participates in islet isolation- and IL-1β-induced apoptosis in rat islets. Furthermore, the system we used might be more generally applicable for the persistent blockage (several days) of pro-apoptotic pathways in the transplanted islets; this days-long protection might potentially be an absolute prerequisite to help transplanted islets better survive the first wave of the non-specific inflammatory attac

Block-Transitive Designs in Affine Spaces

This paper deals with block-transitive $t$-$(v,k,\lambda)$ designs in affine spaces for large $t$, with a focus on the important index $\lambda=1$ case. We prove that there are no non-trivial 5-$(v,k,1)$ designs admitting a block-transitive group of automorphisms that is of affine type. Moreover, we show that the corresponding non-existence result holds for 4-$(v,k,1)$ designs, except possibly when the group is one-dimensional affine. Our approach involves a consideration of the finite 2-homogeneous affine permutation groups.Comment: 10 pages; to appear in: "Designs, Codes and Cryptography

The cost of monitoring in time-based prospective memory

Time-based prospective memory (TBPM) involves remembering to perform actions at specific times in the future. Several studies suggest that monetary consequences improve prospective remembering; however, the effect of monetary consequences on strategic time monitoring (i.e., clock-checking behaviour) in TBPM is still unknown. The present study investigated how the monetary costs on clock-checking affected TBPM accuracy and strategic time monitoring. Participants performed an ongoing lexical decision task while carrying out a TBPM task every two minutes. Motivational incentives were manipulated across three experimental conditions: a single-cost condition in which missed TBPM responses led to monetary deductions, a double-cost condition in which both missed responses and time monitoring led to monetary deductions, and a control condition with no monetary deductions. Overall, the findings indicated that monetary costs on clock-checking prompted more parsimonious strategic time monitoring behaviour, which negatively impacted TBPM accuracy. These results emphasize the importance of weighing the motivational aspects involved in strategic monitoring, shedding light on the complex relationship between clock-checking behaviour, its consequences, and TBPM performance.</p