Towards a novel design method for impact on leading edges

Results of a parametric study concerning low velocity impact on leading edge profiles is presented. This work is the first part of a larger program on the development of an engineering design method for impact on Glare. In this first part, experimental tests and numerical simulations on two-dimensional aluminium leading edge profiles were carried out. An extensive parametric study was done using numerical analysis. Selected configurations have been validated using impact tower testing. Impact tests were done with a solid impactor with a circular diameter on leading edges having a width of 20 mm. Profiles with three different thicknesses and three different sizes were tested. Impact velocities were in the range 1 to 8 m/s. The numerical models predicted the deformation of the leading edges accurately. Important impact parameters were identified and relations were established between impact parameters and geometrical properties of the leading edge profiles. The obtained results give important insight in the set up of simulations and experimentation and in the identification of important parameters of leading edge impact

Electronic and thermal sequential transport in metallic and superconducting two-junction arrays

The description of transport phenomena in devices consisting of arrays of tunnel junctions, and the experimental confirmation of these predictions is one of the great successes of mesoscopic physics. The aim of this paper is to give a self-consistent review of sequential transport processes in such devices, based on the so-called "orthodox" model. We calculate numerically the current-voltage (I-V) curves, the conductance versus bias voltage (G-V) curves, and the associated thermal transport in symmetric and asymmetric two-junction arrays such as Coulomb-blockade thermometers (CBTs), superconducting-insulator-normal-insulator-superconducting (SINIS) structures, and superconducting single-electron transistors (SETs). We investigate the behavior of these systems at the singularity-matching bias points, the dependence of microrefrigeration effects on the charging energy of the island, and the effect of a finite superconducting gap on Coulomb-blockade thermometry.Comment: 23 pages, 12 figures; Berlin (ISBN: 978-3-642-12069-5

Process route selection and process design for antidepressant manufacture

Document(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science

Cholesterol-induced hepatic inflammation does not underlie the predisposition to insulin resistance in dyslipidemic female LDL receptor knockout mice.

Contains fulltext : 154761.pdf (publisher's version ) (Open Access)Chronic inflammation is considered a causal risk factor predisposing to insulin resistance. However, evidence is accumulating that inflammation confined to the liver may not be causal to metabolic dysfunction. To investigate this, we assessed if hepatic inflammation explains the predisposition towards insulin resistance in low-density lipoprotein receptor knock-out (Ldlr (-/-)) mice. For this, wild type (WT) and Ldlr (-/-) mice were fed a chow diet, a high fat (HF) diet, or a high fat, high cholesterol (HFC) diet for 2 weeks. Plasma lipid levels were elevated in chow-fed Ldlr (-/-) mice compared to WT mice. Although short-term HF or HFC feeding did not result in body weight gain and adipose tissue inflammation, dyslipidemia was worsened in Ldlr (-/-) mice compared to WT mice. In addition, dyslipidemic HF-fed Ldlr (-/-) mice had a higher hepatic glucose production rate than HF-fed WT mice, while peripheral insulin resistance was unaffected. This suggests that HF-fed Ldlr (-/-) mice suffered from hepatic insulin resistance. While HFC-fed Ldlr (-/-) mice displayed the anticipated increased hepatic inflammation, this did neither exacerbate systemic nor hepatic insulin resistance. Therefore, our results show that hepatic insulin resistance is unrelated to cholesterol-induced hepatic inflammation in Ldlr (-/-) mice, indicating that hepatic inflammation may not contribute to metabolic dysfunction per se

The natural course of hemodynamically stable pulmonary embolism: Clinical outcome and risk factors in a large prospective cohort study.

Item does not contain fulltextBACKGROUND: Pulmonary embolism (PE) is a potentially fatal disease with risks of recurrent venous thrombotic events (venous thromboembolism [VTE]) and major bleeding from anticoagulant therapy. Identifying risk factors for recurrent VTE, bleeding, and mortality may guide clinical decision making. OBJECTIVE: To evaluate the incidence of recurrent VTE, hemorrhagic complications, and mortality in patients with PE, and to identify risk factors and the time course of these events. DESIGN: We evaluated consecutive patients with PE derived from a prospective management study, who were followed for 3 months, treated with anticoagulants, and underwent objective diagnostic testing for suspected recurrent VTE or bleeding. RESULTS: Of 673 patients with complete follow-up, 20 patients (3.0%; 95% confidence interval [CI], 1.8 to 4.6%) had recurrent VTE. Eleven of 14 patients with recurrent PE had a fatal PE (79%; 95% CI, 49 to 95%), occurring mostly in the first week after diagnosis of initial PE. In 23 patients (3.4%; 95% CI, 2.2 to 5.1%), a hemorrhagic complication occurred, 10 of which were major bleeds (1.5%; 95% CI, 0.7 to 2.7%), and 2 were fatal (0.3%; 95% CI, 0.04 to 1.1%). During the 3-month follow-up, 55 patients died (8.2%; 95% CI, 6.2 to 10.5%). Risk factors for recurrent VTE were immobilization for > 3 days and being an inpatient; having COPD or malignancies were risk factors for bleeding. Higher age, immobilization, malignancy, and being an inpatient were risk factors for mortality. CONCLUSIONS: Recurrent VTE occurred in a small percentage of patients treated for an acute PE, and the majority of recurrent PEs were fatal. Immobilization, hospitalization, age, COPD, and malignancies were risk factors for recurrent VTE, bleeding, and mortality. Close monitoring may be indicated in these patients, precluding them from out-of-hospital start of treatment

Methods for Refinement of Structural Finite Element Models: Summary of the GARTEUR AG14 Collaborative Programme

The finite element model is the main tool used by helicopter manufacturers for the analysis of helicopter structures and in particular for the prediction of vibration. High fidelity models that can accurately represent the structural dynamics are the key to producing effective low vibration designs. Helicopters with ‘jet’ smooth comfort are demanded by discriminating customers who also require ownership of vehicles with high reliability, low maintenance and reduced through life costs. The finite element model is an important tool in the assessment of aircraft modifications after the initial design and production when adverse vibration levels may become apparent. At this stage a structure is available and measured dynamic data from a shake test may be used to validate and improve the initial finite element model. The model derived from test data is not, by itself, comprehensive enough to allow the study and manipulation of the structural dynam-ics but its role in conjunction with the finite element model is a vital step towards improving the helicopter structural design. The main purpose of this GARTEUR collaboration was to explore methods and procedures for improving finite element models through the use of dynamic testing. For the foreseeable future it is expected that shake tests combined with finite element models will be the major tool for improving the dynamic characteristics of the helicopter structural design. It is there-fore of great importance to all participants that the procedure of validating and updating heli-copter finite element models is robust, rigorous and effective in delivering the best match based on realistic engineering adjustments to the finite element model. The industry need for finite element models, the variety of update procedures and their advan-tages are discussed in this paper together with some requirements for dynamic testing. The results of a systematic study on the model updating of a Lynx Mk7 airframe are presented and conclusions drawn. Recommendations are made with regard to performing subsequent dy-namic tests, model updating and for future collaborative study