Geometric scaling of purely-elastic flow instabilities

We present a combined experimental, numerical and theoretical investigation of the geometric scaling of the onset of a purely-elastic flow instability in a serpentine channel. Good qualitative agreement is obtained between experiments, using dilute solutions of flexible polymers in microfluidic devices, and two-dimensional numerical simulations using the UCM model. The results are confirmed by a simple theoretical analysis, based on the dimensionless criterion proposed by Pakdel-McKinley for onset of a purely-elastic instability

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Follow-the-Greens: Towards increased Safety and Efficiency by the Use of Airfield Ground Lighting (AGL). Results from a SESAR real time Simulation.

Taxiing at any major hub airport constitutes a workload intense navigation and monitoring. Although the pilots are supported by signage on the airport surface and possibly even taxiway centerline lights, this task can be complicated even in good weather conditions. Radio communication technology is near capacity limits in many airports today resulting in waiting times for the flight crew to negotiate the next taxi clearance. Apart from well known safety issues this often leads to delays - for the passengers as well - and ultimately impacts the environment. Solutions are given by the European research program SESAR (Single European Sky Air Traffic Management Research) which aims at modernizing and harmonizing the European Aviation network. A new surface traffic management concept dispenses with radio communication and proposes the automated use of AGL with individually switched green taxiway centerline lights indicating the path for the flight crew to be followed. For each aircraft a segment of taxiway centerline lights can be illuminated in front of it. The areas not needed are switched off, minimizing the risk of errors. The new concept is independent from cockpit equipment. The procedure is called “Follow-the-Greens”. The SESAR European Airports Consortium “SEAC” validated the new concept under the leadership of Fraport with its partners DFS, ENAV, Flightdecksystems and ATRiCS under the support of Lufthansa in 2013. A real-time simulation platform for the Frankfurt airport area layout combined two Airbus A320 fixed based simulators with highly integrated controller working positions. The concept’s effect on taxi times and route deviation was examined. The appropriate length of the green line, different ways of (de-)activating the lights and different visualizations of a stop instruction were tested. Results from the successful validation with twenty pilots are reported in this paper indicating a safer, easier, quicker and greener surface traffic management concept for the future