This paper describes a particular procedure, based on ASTM D7214 and ASTM E 2412, which has been defined to improve oil oxidation quantification in used engine oils. Taking into account typical problems that can be found in this type of samples, thermal oxidation and fuel dilution, response on FT-IR spectra has been analyzed considering also the effect of oil formulation. Two special zones have been considered inside the typical wave number range for oxidation quantification, where those problems can be detected and assessed more easily. Zone A between 1,725 cm , where esters as main products for detection of fuel dilution problems when diesel engine is operating with biodiesel.

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A study of the injection process and spray behavior has been made for three different fuels. In particular, blends of rapeseed methyl ester (RME) with standard diesel fuel at 5% and 30% of biodiesel have been used for the current study, as well as pure RME.Hydraulic characterization of an 8-hole nozzle has been carried out using these three fuels, in order to explore and analyze the influence of fuel properties on mass flow rate and momentum flux at the nozzle exit. Additionally, spray visualization tests have been made in order to get information about spray cone angle, which allows the characterization of air-fuel mixing process. Finally, a theoretical derivation has been used to obtain further details of the microscopic characteristics of the spray and compare air-fuel mixing efficiency for the different biodiesel blends.

BackgroundShort sequence mapping methods for Next Generation Sequencing consist on a combination of seeding techniques followed by local alignment based on dynamic programming approaches. Most seeding algorithms are based on backward search alignment, using the Burrows Wheeler Transform, the Ferragina and Manzini Index or Suffix Arrays. All these backward search algorithms have excellent performance, but their computational cost highly increases when allowing errors. In this paper, we discuss an inexact mapping algorithm based on pruning strategies for search tree exploration over genomic data.ResultsThe proposed algorithm achieves a 13x speed-up over similar algorithms when allowing 6 base errors, including insertions, deletions and mismatches. This algorithm can deal with 400 bps reads with up to 9 errors in a high quality Illumina dataset. In this example, the algorithm works as a preprocessor that reduces by 55% the number of reads to be aligned. Depending on the aligner the overall execution time is reduced between 20–40%.ConclusionsAlthough not intended as a complete sequence mapping tool, the proposed algorithm could be used as a preprocessing step to modern sequence mappers. This step significantly reduces the number reads to be aligned, accelerating overall alignment time. Furthermore, this algorithm could be used for accelerating the seeding step of already available sequence mappers. In addition, an out-of-core index has been implemented for working with large genomes on systems without expensive memory configurations.

A mathematical model has been used t o evaluate the effect of diesel engine operating conditions on nitric oxide formation and emissions. Although there are several formation pathways during diesel Combustion, only the supposed most important one was considered in the present work: the thermal mechanism. The effect of the engine operating conditions was simulated by means of schematical variations of local temperature and fuel-air ratio of the mixture. The evolution of these local variables is described by three characteristic time intervals, which define the timing of the following items: the temperature and pressure peaks; the dilution of burnt products with surrounding air; and the decay of temperature and pressure due to expansion. In addition, the temperature peak was related to the adiabaticyame temperature, which was previously calculated for each mixture condition. A computational parametric study was carried out by varying each of the local mixture parameters and characteristic times, either separately or in combinations. The trends obtained show a qualitative agreement with those obtained by other authors from experimental tests on different diesel engines. The analysis of these trends contributes to a better understanding of the sources of NO diesel emissions and could provide guidelines for cleaner diesel engine design.

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