Combustion and emission studies of a common-rail direct injection diesel engine with various injector nozzles

Fuel injection has a critical role in an internal combustion engine and a significant effect on the quality of the fuel spray. In turn, fuel spray directly affects an engine´s combustion, efficiency, power and emissions. This study evaluated three different injector nozzles in a highspeed, non-road diesel engine. It was run on diesel fuel oil (DFO) and testing was conducted at three different engine loads (100%, 75% and 50%) and at two engine speeds (2,200 rpm and 1,500 rpm). The nozzles had 6, 8 and 10 holes and a relatively high mass flow rate (HF). The study investigated and compared injection and combustion characteristics, together with gaseous emissions. The combustion parameters seemed to be very similar with all studied injector nozzles. The emission measurements indicated general reductions in hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx) at most load/speed points when using the 6- and 10-hole nozzles instead of the reference 8-hole nozzles. However, smoke number increased when the alternative nozzles were used

BRST extension of the Faddeev model

The Faddeev model is a second class constrained system. Here we construct its nilpotent BRST operator and derive the ensuing manifestly BRST invariant Lagrangian. Our construction employs the structure of Stuckelberg fields in a nontrivial fashion.Comment: 4 pages, new references adde

Waste fish oil as an alternative renewable fuel for IC engines

Received: January 31st, 2021 ; Accepted: April 10th, 2021 ; Published: April 30th, 2021 ; Correspondence: [email protected] are potential fuels for internal combustion engines because of they have advantageous properties such as biodegradability, renewability, high oxygen content and low sulphur. However, the high viscosity, surface tension, and density of crude bio-oils pose challenges for engine use. Those properties affect fuel spray characteristics, mixture formation and combustion. In turn, these impact engine, efficiency, power and emissions. This study investigated the use of crude fish oil (FO) at medium and low engine-loads at two engine speeds in an off-road engine. The injectors had 6-hole high flow rate tips. The results were compared with those of fossil diesel fuel oil (DFO). Fish oil increased hydrocarbon (HC), carbon monoxide (CO) and partly oxides of nitrogen (NOx) emissions. Smoke number, however, decreased. Crude fish oil also showed lowered total particle number (TPN) at low load at low engine-speed compared with DFO

Quantum Field Theory and Differential Geometry

We introduce the historical development and physical idea behind topological Yang-Mills theory and explain how a physical framework describing subatomic physics can be used as a tool to study differential geometry. Further, we emphasize that this phenomenon demonstrates that the interrelation between physics and mathematics have come into a new stage.Comment: 29 pages, enlarged version, some typewritten mistakes have been corrected, the geometric descrition to BRST symmetry, the chain of descent equations and its application in TYM as well as an introduction to R-symmetry have been added, as required by mathematicia

THERMAL EFFECTS ON THE CATALYSIS BY A MAGNETIC FIELD

We show that the formation of condensates in the presence of a constant magnetic field in 2+1 dimensions is extremely unstable. It disappears as soon as a heat bath is introduced with or without a chemical potential. We point out some new nonanalytic behavior that develops in this system at finite temperature.Comment: 10 pages, plain Te

Dynamical Symmetry Breaking in Planar QED

We investigate (2+1)-dimensional QED coupled with Dirac fermions both at zero and finite temperature. We discuss in details two-components (P-odd) and four-components (P-even) fermion fields. We focus on P-odd and P-even Dirac fermions in presence of an external constant magnetic field. In the spontaneous generation of the magnetic condensate survives even at infinite temperature. We also discuss the spontaneous generation of fermion mass in presence of an external magnetic field.Comment: 34 pages, 8 postscript figures, final version to appear on J. Phys.

Generalised chiral QED2 : Anomaly and Exotic Statistics

We study the influence of the anomaly on the physical quantum picture of the generalized chiral Schwinger model defined on the circle. We show that the anomaly i) results in the background linearly rising electric field and ii) makes the spectrum of the physical Hamiltonian nonrelativistic without a massive boson. The physical matter fields acquire exotic statistics . We construct explicitly the algebra of the Poincare generators and show that it differs from the Poincare one. We exhibit the role of the vacuum Berry phase in the failure of the Poincare algebra to close. We prove that, in spite of the background electric field, such phenomenon as the total screening of external charges characteristic for the standard Schwinger model takes place in the generalized chiral Schwinger model, too.Comment: LATEX file, 36 pp., to appear in Phys.Rev.

Characterization of site-specific GPS errors using a short-baseline network of braced monuments at Yucca Mountain, southern Nevada

We use a short-baseline network of braced monuments to investigate site-specific GPS effects. The network has baseline lengths of ∼10, 100, and 1000 m. Baseline time series have root mean square (RMS) residuals, about a model for the seasonal cycle, of 0.05–0.24 mm for the horizontal components and 0.20–0.72 mm for the radial. Seasonal cycles occur, with amplitudes of 0.04–0.60 mm, even for the horizontal components and even for the shortest baselines. For many time series these lag seasonal cycles in local temperature measurements by 23–43 days. This could suggest that they are related to bedrock thermal expansion. Both shorter-period signals and seasonal cycles for shorter baselines to REP2, the one short-braced monument in our network, are correlated with temperature, with no lag time. Differences between REP2 and the other stations, which are deep-braced, should reflect processes occurring in the upper few meters of the ground. These correlations may be related to thermal expansion of these upper ground layers, and/or thermal expansion of the monuments themselves. Even over these short distances we see a systematic increase in RMS values with increasing baseline length. This, and the low RMS levels, suggests that site-specific effects are unlikely to be the limiting factor in the use of similar GPS sites for geophysical investigations