Search

In this paper we are concerned with the multiplicity of solutions near resonance for the following nonlinear equation: −Δu = λu + f(x,u) associated with the Dirichlet boundary condition, where f satisfies some appropriate conditions. We will treat this problem in the framework of dynamical systems. It will be shown that there exist a one-sided neighborhood Λ− of the eigenvalue μk of the Laplacian operator and a dense subset D of R such that the equation has at least four distinct nontrivial solutions generically for λ ∈ Λ− ∩D. [ABSTRACT FROM AUTHOR]

In this paper we first give a criterion on stability of equilibrium solutions for autonomous systems with constraints. Then we discuss the relationship between asymptotic behaviors of an asymptotically autonomous system with constraint and its limit system. Finally as an example, we revisit an extreme ideology model proposed in the literature and give a more detailed description on the dynamics of the system. [ABSTRACT FROM AUTHOR]

In this study, the crankcase gas temperature, flow rate, gaseous emissions (NOx, CO and HC) and particle emissions (particle size distribution, number and mass concentration, geometric mean diameter) compared with tailpipe are investigated in a light-duty common rail diesel engine. It is shown that the emissions from the crankcase are mainly affected by the second in-cylinder pressure peak. The crankcase gas temperature varies between 52 °C and 68 °C, and the crankcase gas flow rate slightly increases with load and speed but does not vary much with injection timing. The CO emission from crankcase is about 2%−5% of that from tailpipe, the NOx emissions are only about 1% and the HC emissions are more than 10%. The blow-by gas percentage is 10−8 order and reduces with heavier engine load and faster engine speed. The blow-by HC emission percentage varies from 5% to 35%. As engine load is increased and engine speed is decreased, the nuclei mode particles of crankcase reduce and the accumulation mode particles increase. Furthermore, the particle total number concentration increases with load but decreases with speed and retarding injection timing. The total mass concentration increases with load but rises and falls with speed and injection timing. The crankcase particle geometric mean diameter based on mass is nearly twice larger than that of tailpipe, while the ones based on number are rarely different except the higher load. [ABSTRACT FROM AUTHOR]

In this study, the experiment is conducted on a four-cylinder direct-injection diesel engine equipped with a turbocharger and a high-pressure common rail injection system. The test fuels include diesel from direct coal liquefaction, diesel and their blends. The effects of exhaust gas recirculation and retarded injection on the combustion, the nitrogen oxide emissions and the soot emissions under low-temperature combustion are explored. The results indicate that exhaust gas recirculation and retarded injection can effectively lengthen the ignition delay of test fuels especially for diesel from direct coal liquefaction. The ignition delays of all the fuels become shorter with increasing engine load, but the variation rates for diesel from direct coal liquefaction and diesel are not the same. Retarded injection can lead to a soot hump for the four fuels, but it reflects this soot change for diesel from direct coal liquefaction more sensitively than for diesel. Diesel from direct coal liquefaction produces lower nitrogen oxide emissions and lower soot emissions than diesel does under low-temperature combustion. A control strategy that achieves reduction in both the nitrogen oxide emissions and the soot emissions will cause the fuel consumption to deteriorate. [ABSTRACT FROM PUBLISHER]