Detached Eddy Simulation of Restricted Shock Separated flow in a Thrust Optimized Contoured nozzle

Detached Eddy Simulation of restricted shock separated (RSS) flow has been performed to understand the physics of complex cap-shock pattern, which is the key cause of separated flow transition in the rocket nozzles. High-order shock-capturing numerical schemes are necessary to understand this complex flow. Hence a fifth order monotonicity preserving weighted essentially non-oscillatory (MPWENO) scheme is used here for good numerical resolution

Non-legislated emissions and PN of two passenger cars with gasoline-butanol blends

Increasing the sustainability of individual transportation and replacing a part of fossil energy in traffic by renewable energy carriers are worldwide important objectives. Bioalcohols are generally recognized as one of very useful alternatives. The global share of bioethanol used for transportation is continuously increasing. Butanol, a four-carbon alcohol, is considered in the last years as an interesting alternative fuel, both for diesel and for gasoline application. Its advantages for engine operation are: good miscibility with gasoline and diesel fuels, higher calorific value than ethanol, lower hygroscopicity, lower corrosivity and possibility of replacing aviation fuels. In the present work, the emissions of two gasoline vehicles – with older and with newer technology – were investigated in dynamic-, stationary and cold start operation

A priori analysis of subgrid-scale models for shock wave / boundary layer interaction

This study addresses the subgrid-scale modeling issue for large eddy simulation of shock wave / boundary layer interaction. By using a reference flow database, obtained by direct numerical simulation, a priori testing of the most prominent LES models is carried out. The various modelling and filtering approaches are discussed and compared, leading to suggest a priori the most appropriate closure strategy

Influences of special driving situations on emissions of passenger cars

Emission factors and emission inventories are an im-portant source of data for compiling and modelling the emissions of traffic in different situations. There is in EU a continuous work and development of emission data inventories, [1–6]. Since the introduction (in 2017) of the road-testing (RDE – real driving emissions) as an obligatory element of the legal testing procedures, the increased amount of RDE-data can be used for different objectives, such as: further development of emission inventories, compliance with “In-Service Conformity” (ISC, EU regulation 2018/1832) and market surveillance activities (EU regulation 2018/858). Extensive activities of testing RDE by means of PEMS (portable emissions measuring systems) have been per-formed in the last years, aiming not only the emissions but also the improvements of instrumentation, of testing procedures and of evaluation [5–17]. A well-known fact is that the emissions at cold start, during the warm-up and at the low speed phases of urban operation, both in the laboratory and on the road, tend to be higher for all pollutants [13, 18–24]. This fact supports even the idea for future introduction of urban emission limits for the short trips, which are very frequent in Europe [5]. In order to enable an automatic co-evaluation of emissions from the special (non)driving situations, the necessary definitions were proposed in the present work. With these definitions, the RDE data of 7 vehicles were processed and the emissions in special driving situations were obtained (part 1). Additionally, some special situations like cold start, warm-up and stop&go were reproduced on the chassis dynamometer with cars of different ages and different tech-nology (part 2). This paper gives some new insights in the topic of emissions from special driving situations

Non-Regulated Emissions and PN of Two Passenger Cars with Diesel-Butanol Blends

Biofuels represent one of the alternatives to obtain the CO2-neutral propulsion of IC-engines. Butanol, which can be produced from biomass, is considered and was investigated in the last years due to the very advantageous characteristics of this alternative fuel. Butanol can be easily and irreversibly blended both with light (gasoline) and heavier (Diesel) fuels. Comparing with ethanol it has the advantages of: higher calorific value, lower hygroscopicity and lower corrosivity. It can replace the aviation fuels. This paper presents the emission results obtained on two Diesel passenger cars with different technology (Euro2 and Euro6c) and with addition of Butanol to Diesel fuel, as a part of the research project DiBut (Diesel and Butanol). Interesting results are given about some non-legislated (non-regulated) components, Acetaldehyde (MeCHO) and Formaldehyde (HCHO) and about the PN-emissions with/without DPF

Activity of minocycline against Toxoplasma gondii infection in mice

The chemotherapeutic activity of minocycline, a semi-synthetic tetracycline analogue, was evaluated in a murine model of toxoplasmosis. A lethal acute toxoplas-mosis was produced by injecting 105 tachyzoites of the RH strain of Toxoplasma gondii into the peritoneal cavities of Swiss-Webster mice. When infected mice were treated once daily for 12 days, starting 2 h after challenge, the survival and cure rates were 100% and 40% respectively after minocycline alone (100 mg/kg per day), 0% and 0% after pyrimethamine alone (8.5 mg/kg per day), and 100% and 50% after combination of the two drugs at the same dosages. Absolute survival and cure with minocycline were observed when mice were treated with two daily doses of 100 mg/kg for 12 days. Mice chronically infected with a low virulent strain of T. gondii (Me49) showed a significant reduction in the number of brain cysts after three weeks of treatment with 50 mg/kg per day of minocycline. Minocycline serum levels after a single oral administration of 50 mg/kg or 100 mg/kg to normal mice, peaked at 1.8 mg/1 and 10 mg/1 after 1 h, respectively, and showed an extended half-lif

POV: Obama's ban on juvenile solitary confinement

Point of view article in BU Toda

Statistical Evaluation of the Shock Wave Boundary Layer Interaction Phenomenon

Turbulent velocity and thermal correlations from direct numerical simulation data of a spatially growing compressible turbulent boundary layer interacting with an impinging shock are discussed. The cross-stream variation of the velocity second-moments and the thermal fluxes one boundary layer thickness upstream of the shock impingement point are discussed. Other correlations are examined to further statistically quantify the effect of the oblique shock-turbulence interaction