850 research outputs found
A logarithmic encoder for binary word compression
Logarithmic encoding procedure and error analysis for binary word compressio
Vegetable Oils as Fuels in Diesel Engine. Engine Performance and Emissions
AbstractThe EU new energy strategy represents a challenge and a boost for industries and researchers pushing them to find new solutions to supply the energy demand complying with new environmental requests. The transport sector is one of the most addicted to oil product and then pollutant. A new bio-fuels generation is being studied, but the use of the ones already available should be increased. The use of vegetable oils (VO) and waste cooking oils (WCO) could represent interesting alternative fuels for Diesel engines in some specific applications (i.e., public transportation, hybrid or marine propulsion, etc.). Moreover, VO can be produced almost everywhere in the world in relatively small plants, and WCO would represent the use of a waste material which otherwise should be disposed. However, operating a Diesel engine (DE) with a different fuel might results in some problems. Indeed VO and WCO have different characteristics compared to Diesel fuel (i.e, a smaller heating value, a larger density and viscosity), and this can affect the operation of a DE. In particular the DE is expected to have some problem at the injection system and power loss.In this work different vegetable oils (both straight and waste) are used to fuel a DE in automotive configuration and study its behavior. Tests are performed using a turbocharged, four stroke, four cylinders, water cooled, common-rail multijet DE. The influence of fuel used on engine power, specific consumption, efficiency, and exhaust opacity, are compared with those obtained fuelling with Diesel fuel
Measurement of the ΔS=-ΔQ Amplitude from K_(e3)^0 Decay
We have measured the time distribution of the π^+e^-ν and π^-e^+ν modes from initial K^0's in a spark-chamber experiment performed at the Bevatron. From 1079 events between 0.2 and 7 K_S^0 lifetime, we find ReX=-0.069±0.036, ImX=+0.108_(-0.074)^(+0.092). This result is consistent with X=0 (relative probability = 0.25), but more than 4 standard deviations from the existing world average, +0.14 -0.13i
Measurement of the Luminosity in the ZEUS Experiment at HERA II
The luminosity in the ZEUS detector was measured using photons from electron
bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher
luminosity. At the same time the luminosity-measuring system of the ZEUS
experiment was modified to tackle the expected higher photon rate and
synchrotron radiation. The existing lead-scintillator calorimeter was equipped
with radiation hard scintillator tiles and shielded against synchrotron
radiation. In addition, a magnetic spectrometer was installed to measure the
luminosity independently using photons converted in the beam-pipe exit window.
The redundancy provided a reliable and robust luminosity determination with a
systematic uncertainty of 1.7%. The experimental setup, the techniques used for
luminosity determination and the estimate of the systematic uncertainty are
reported.Comment: 25 pages, 11 figure
New Measurements of Nucleon Structure Functions from CCFR/NuTeV
We report on the extraction of the structure functions F_2 and Delta xF_3 =
xF_3nu-xF_3nub from CCFR neutrino-Fe and antineutrino-Fe differential cross
sections. The extraction is performed in a physics model independent (PMI) way.
This first measurement for Delta xF_3, which is useful in testing models of
heavy charm production, is higher than current theoretical predictions. Within
5% the F_2 (PMI) values measured in neutrino and muon scattering are in
agreement with the predictions of Next-to-Leading-Order PDFs (using massive
charm production schemes), thus resolving the long-standing discrepancy between
the two measurements.Comment: 3 pages, Presented by Arie Bodek at DPF2000 Conference, Columbus,
Ohio, Aug. 200
Extraction of R = sigma_L/sigma_T from CCFR nu_mu-Fe and nubar_mu-Fe differential cross sections
We report on the extraction of R=sigma_L/sigma_T from CCFR nu_mu-Fe and
nubar_mu-Fe differential cross sections. The CCFR differential cross sections
do not show the deviations from the QCD expectations that are seen in the CDHSW
data at very low and very high x. R as measured in nu_mu scattering is in
agreement with R as measured in muon and electron scattering. All data on R for
Q^2 > 1 GeV^2 are in agreement with a NNLO QCD calculation which includes
target mass effects. We report on the first measurements of R in the low x and
Q^2 < 1 GeV^2 region (where an anomalous large rise in R for nuclear targets
has been observed by the HERMES collaboration).Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let
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