Государственные закупки как механизм стимулирования производства инновационных товаров, работ и услуг

Отмечена существенная роль сферы государственного заказа в процессе формирования национальной институциональной среды, в том числе в развитии производства инновационных товаров, работ и услуг. Констатирована терминологическая неясность понятия инновационного товара, работы, услуги для целей государственных закупок. Проанализированы особенности институтов в сфере размещения государственных заказов и отмечено противодействие сложившейся в России системы закупок целям стимулирования производства инновационной продукции. Предложены меры выхода из сложившейся ситуации применительно к закупкам инновационных товаров, работ и услуг

Large Eddy Simulation of Soot Formation in a Real Aero-Engine Combustor Using Tabulated Chemistry and a Quadrature-Based Method of Moments

Accepted manuscript of the ASME Journal of Engineering for Gas Turbines and Power Paper "Large Eddy Simulation of Soot Formation in a Real Aero-Engine Combustor Using Tabulated Chemistry and a Quadrature-Based Method of Moments"

Large Eddy Simulation of Soot Formation in a Real Aero-Engine Combustor Using Tabulated Chemistry and a Quadrature-Based Method of Moments

Considering the increasingly stringent targets for aircraft emissions, CFD is becoming a viable tool for improving future aero-engine combustors. However, predicting pollutant formation remains challenging. In particular, directly solving the evolution of soot particles is numerically expensive. To reduce the computational cost but retain detailed physical modeling, quadrature-based moments methods can be efficiently employed to approximate the particle number density function (NDF). An example is the recently developed split-based extended quadrature method of moments (S-EQMOM), which enables a continuous description of the soot particles’ NDF, essential to consider particle oxidation accurately. This model has shown promising results in laminar premixed flames up to turbulent laboratory scale configurations. However, the application to large-scale applications is still scarce. In this work, the S-EQMOM model is applied to the Rolls-Royce BR710 aero-engine combustor to investigate the soot evolution process in practically relevant configurations. For this, the soot model is embedded into a high-fidelity simulation framework, consisting of large eddy simulation for the turbulent flow and mixing and the flamelet generated manifold method for chemistry reduction. An additional transport equation for polycyclic aromatic hydrocarbons is solved to model their slow chemistry and the transition from the gaseous phase to the solid phase. Simulations are performed for different operating conditions (idle, approach, climb, take-off) to validate the model using experimental data. Subsequently, the results are analyzed to provide insights into the complex interactions of hydrodynamics, mixing, chemistry, and soot formation

Carrier relaxation, pseudogap, and superconducting gap in high-Tc cuprates: A Raman scattering study

We describe results of electronic Raman-scattering experiments in differently doped single crystals of Y-123 and Bi-2212. The comparison of AF insulating and metallic samples suggests that at least the low-energy part of the spectra originates predominantly from excitations of free carriers. We therefore propose an analysis of the data in terms of a memory function approach. Dynamical scattering rates and mass-enhancement factors for the carriers are obtained. In B2g symmetry the Raman data compare well to the results obtained from ordinary and optical transport. For underdoped materials the dc scattering rates in B1g symmetry become temperature independent and considerably larger than in B2g symmetry. This increasing anisotropy is accompanied by a loss of spectral weight in B2g symmetry in the range between the superconducting transition at Tc and a characteristic temperature T* of order room temperature which compares well with the pseudogap temperature found in other experiments. The energy range affected by the pseudogap is doping and temperature independent. The integrated spectral loss is approximately 25% in underdoped samples and becomes much weaker towards higher carrier concentration. In underdoped samples, superconductivity related features in the spectra can be observed only in B2g symmetry. The peak frequencies scale with Tc. We do not find a direct relation between the pseudogap and the superconducting gap.Comment: RevTeX, 21 pages, 24 gif figures. For PostScript with embedded eps figures, see http://www.wmi.badw-muenchen.de/~opel/k2.htm

Ein probabilistisches Verfahren für die Bestimmung ablagerungskritischer Teilbereiche einer Mischkanalisation

Sediments in combined systems (CS) significantly increase loads emitting via combined sewer overflows. In future prognosticated changes in the storm water characteristics, decreasing popu-lation or water conservation will probably worsen these effects. Various actions can prevent the formation of large quantities of sediments whose amounts change considerably over time and space within the sewer. Information about the whereabouts of deposit can be obtained by visual inspection or mathematical modeling. Both approaches require large efforts. Furthermore, presently available deterministic sewer-quality models with sediment transport were found to be over-parameterized and inherit large uncertainties. Mathematical models as the semi-stochastic sediment transport model are still able to efficiently identify areas with risk of sedimentation. This category of models does not use a single parameter set obtained from calibrating the quality model but varies these parameters instead stochastically within a Monte-Carlo Simulation. The investigation aimed (1) to model the amount of mobile sediments that effect the load distribution during wet weather flow and (2) to quantify the areas with risk of sedimentation within a combined sewerage.A detailed field study showed that readily erodible sediments are most important pollutant based process affecting the load distribution during wet weather flow. Based on this finding, a structured hydrological-stochastic sewer quality model was developed. The simplified conceptual model represents the whole sewer system including the pipes with small cross-sections (less than or equal to DN 300) because in small CS the corresponding part amounts to more than 50% of the total length. The simulations’ results were compared against field data. The results demonstrate validity of the approach. The investigation showed in particular:(1) The simulated total length of sewers with risk of sedimentation of 2’998 m agrees well with monitoring data of 3’121 m.(2) The submodel referring to the transport of gross solids effectively reproduce the deposit observed in reaches with intermittent flow. This allows for evaluation scenarios and management strategies that deal with demographic change or water conservation