297 research outputs found

    IMECE2005-79432 IMPROVING ETHANOL LIFE CYCLE ENERGY EFFCIENCY BY DIRECT COMBUSTION OF WET ETHANOL IN HCCI ENGINES

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    ABSTRACT Homogenous Charge Compression Ignition (HCCI) is a relatively new engine technology with fundamental differences over conventional engines. HCCI engines are intrinsically fuel flexible, and can run on low grade fuels, as long as the fuel can be evaporated and heated to the point of ignition. In particular, HCCI engines can run on wet ethanol with high concentration of water. Considering that much of the energy required for processing the ethanol is spent in distillation and dehydration, direct use of wet ethanol in an HCCI engine considerably shifts the energy balance in favor of ethanol. The results of the paper show that an HCCI engine with efficient heat recovery can operate on a 35-65% volumetric mixture of ethanol and water, while achieving a high efficiency (38.7%) and very low NO x (1.6 parts per million, clean enough to meet any existing or oncoming emissions standards). Operation of the HCCI engine with 35% ethanol by volume reduces the energy required for distillation and dehydration from 37% to 3% of the overall energy of ethanol and coproducts. The net energy gain increases considerably, from 21% to 55% of the total energy value of the fuel and coproducts. Wet ethanol combustion in HCCI engines shows great potential for improving the ethanol energy balance, and merits more detailed analysis and experimental evaluation

    Stochastics theory of log-periodic patterns

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    We introduce an analytical model based on birth-death clustering processes to help understanding the empirical log-periodic corrections to power-law scaling and the finite-time singularity as reported in several domains including rupture, earthquakes, world population and financial systems. In our stochastics theory log-periodicities are a consequence of transient clusters induced by an entropy-like term that may reflect the amount of cooperative information carried by the state of a large system of different species. The clustering completion rates for the system are assumed to be given by a simple linear death process. The singularity at t_{o} is derived in terms of birth-death clustering coefficients.Comment: LaTeX, 1 ps figure - To appear J. Phys. A: Math & Ge

    The Present Habitability Potential of Gale Crater: What We Have Learned So Far From Mars Science Laboratory

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    The Mars Science Laboratory mission has comprehensively interrogated the surface environment of Mars as it explores Gale Crater. Both chemical and physical attributes of the present environment have been measured over the course of the mission, enabling us to compare the present state of the martian surface with the environmental requirements of prokaryotic microbes. While this approach does not exclude the possibility of martian life that may have evolved to adapt to the present conditions, it is advantageous in that it allows us to evaluate environmental requirements of known life and also provide insight into the likelihood of forward contamination by Earth organisms with the comparison of their environmental requirements with the measured attributes of the environment at Gale Crater. We have already modeled a paleoenvironment with high habitability potential (HP) based upon chemistry, mineralogy and other geological evidence such as sedimentary structures and larger scale geomorphology [1]. In this report, we turn our attention to the present HP of the Yellowknife Bay area, including the importance of the physical environmental metrics such as atmospheric pressure, air and ground temperature, ionizing radiation, wind speed and direction, slope, etc

    Highlights from the Pierre Auger Observatory

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    The Pierre Auger Observatory is the world's largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km2^2 str and provides us with an unprecedented quality data set. The performance and stability of the detectors and their enhancements are described. Data analyses have led to a number of major breakthroughs. Among these we discuss the energy spectrum and the searches for large-scale anisotropies. We present analyses of our Xmax_{max} data and show how it can be interpreted in terms of mass composition. We also describe some new analyses that extract mass sensitive parameters from the 100% duty cycle SD data. A coherent interpretation of all these recent results opens new directions. The consequences regarding the cosmic ray composition and the properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray Conference, Rio de Janeiro 201

    Screening of MAMLD1 Mutations in 70 Children with 46,XY DSD: Identification and Functional Analysis of Two New Mutations

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    More than 50% of children with severe 46,XY disorders of sex development (DSD) do not have a definitive etiological diagnosis. Besides gonadal dysgenesis, defects in androgen biosynthesis, and abnormalities in androgen sensitivity, the Mastermind-like domain containing 1 (MAMLD1) gene, which was identified as critical for the development of male genitalia, may be implicated. The present study investigated whether MAMLD1 is implicated in cases of severe 46,XY DSD and whether routine sequencing of MAMLD1 should be performed in these patients

    Extreme genomic erosion after recurrent demographic bottlenecks in the highly endangered Iberian lynx

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    Background: Genomic studies of endangered species provide insights into their evolution and demographic history, reveal patterns of genomic erosion that might limit their viability, and offer tools for their effective conservation. The Iberian lynx (Lynx pardinus) is the most endangered felid and a unique example of a species on the brink of extinction. Results: We generate the first annotated draft of the Iberian lynx genome and carry out genome-based analyses of lynx demography, evolution, and population genetics. We identify a series of severe population bottlenecks in the history of the Iberian lynx that predate its known demographic decline during the 20th century and have greatly impacted its genome evolution. We observe drastically reduced rates of weak-to-strong substitutions associated with GC-biased gene conversion and increased rates of fixation of transposable elements. We also find multiple signatures of genetic erosion in the two remnant Iberian lynx populations, including a high frequency of potentially deleterious variants and substitutions, as well as the lowest genome-wide genetic diversity reported so far in any species. Conclusions: The genomic features observed in the Iberian lynx genome may hamper short- and long-term viability through reduced fitness and adaptive potential. The knowledge and resources developed in this study will boost the research on felid evolution and conservation genomics and will benefit the ongoing conservation and management of this emblematic species

    A survey of results on mobile phone datasets analysis

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