STUDY OF THERMAL DECOMPOSITION AND IGNITION TEMPERATURE OF BAGASSE, COAL AND THEIR BLENDS

In Brazil, due to its availability, sugar cane bagasse has a high potential for power generation. The knowledge of ignition behavior, as well as the knowledge of the chemical kinetics, in of fuels combustion process is important features in boilers projects and in the stability of the combustion process control. The aim of this study is to investigate the thermal behavior of sugar cane bagasse, coal and their blends. The methodology proposed by Tognotti et al. (1985) was applied to determine the ignition temperature for all samples. Ignition temperatures were 256oC for neat bagasse and 427oC for neat coal, and 275oC for both blends (50-50% and 25-75%). The Model-Free Kinetics was applied to determine the apparent activation energy (Eα) of the thermal decomposition of sugar cane bagasse. For the two major events of mass loss of bagasse which correspond to the thermal decomposition of organic matter (mainly hemicellulose, cellulose and lignin), average values of Eα were obtained for both combustion and pyrolysis processes. In synthetic air atmosphere, the Eα were 170.8±26.3 kJ⋅mol-1 and 277.8±58.6 kJ⋅mol-1, while in nitrogen atmosphere, the Eα were 185.0 ± 11.4 kJ⋅mol-1 and 82.1±44.4 kJ⋅mol-1. The results obtained can be explained by synergistic effects when both bagasse and coal were blended, changing the fuel reactivity

Ignition Risks of Biomass Dust on Hot Surfaces

Combustible biomass dusts are formed at various handling stages, and accumulations of these dusts can occur on hot surfaces of electrical and mechanical devices and can pose fire risks. This study evaluates the ignition characteristics of dust from two types of biomass commonly used in the U.K. power stations: herbaceous miscanthus and woody pine. The ignition risks of the individual biomass and their blends in two different weight ratios, 90 wt % pine to 10 wt % miscanthus and 50 wt % pine to 50 wt % miscanthus, were investigated. Biomass–biomass blends represent the power plant scenario where a number of biomass are fired under daily operation, and thus, dust sedimentation could consist of material blends. The influence of washing pretreatment (particularly to remove catalytic potassium) on the ignition behavior of these dusts was investigated. Fuel characterization via proximate and ultimate analyses was performed on all fuels and combustion characteristics via thermogravimetric analysis (TGA). The risk of self-ignition propensity of both untreated and washed biomass was ranked graphically using the activation energy (Ea) for combustion and the temperature of maximum weight loss (TMWL) determined from the derivative TGA (DTG) curve. It was found that the TMWL and Ea of washed biomass were higher than those of the untreated biomass, implying a lower self-ignition risk. Similar analyses were performed on untreated and washed blends, and comparable results were observed. The ignition characteristics were studied following the British Standard test methods for determining the minimum ignition temperature of a 5 mm dust layer on a heated surface. It was found that the washed individual biomass and their blends revealed slightly higher dust ignition temperatures than their respective untreated counterparts, a 20 and 10 °C difference for individual biomass and blends, respectively. The effect of washing on the ignition delay time was more obvious for pine than for miscanthus, but the time difference between the untreated and washed biomass never exceeded 4 min for all biomass and blends. The biomass pretreatment method of washing did change the combustion and self-ignition characteristics of biomass dust, and there was evidence of potassium being leached from the fuels upon washing (particularly miscanthus). This is considered the main reason for the increase in the minimum ignition temperature. While the washed biomass is found to have a lower ignition risk, it should be noted that the result (validated for up to 5 mm thickness) is not significant enough to influence plant operations for the ignition risk from thin dust layers according to the National Fire Protection Association (NFPA) standard

Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam

We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.Comment: 14 pages, 12 figures. Submitted for publication to Physical Review

Measurement of Through-Going Particle Momentum By Means Of Multiple Scattering With The ICARUS T600 TPC

The ICARUS collaboration has demonstrated, following the operation of a 600 ton (T600) detector at shallow depth, that the technique based on liquid Argon TPCs is now mature. The study of rare events, not contemplated in the Standard Model, can greatly benefit from the use of this kind of detectors. In particular, a deeper understanding of atmospheric neutrino properties will be obtained thanks to the unprecedented quality of the data ICARUS provides. However if we concentrate on the T600 performance, most of the $\nu_\mu$ charged current sample will be partially contained, due to the reduced dimensions of the detector. In this article, we address the problem of how well we can determine the kinematics of events having partially contained tracks. The analysis of a large sample of atmospheric muons collected during the T600 test run demonstrate that, in case the recorded track is at least one meter long, the muon momentum can be reconstructed by an algorithm that measures the Multiple Coulomb Scattering along the particle's path. Moreover, we show that momentum resolution can be improved by a factor two using an algorithm based on the Kalman Filtering technique

Results of the IGEC-2 search for gravitational wave bursts during 2005

The network of resonant bar detectors of gravitational waves resumed coordinated observations within the International Gravitational Event Collaboration (IGEC-2). Four detectors are taking part in this collaboration: ALLEGRO, AURIGA, EXPLORER and NAUTILUS. We present here the results of the search for gravitational wave bursts over 6 months during 2005, when IGEC-2 was the only gravitational wave observatory in operation. The network data analysis implemented is based on a time coincidence search among AURIGA, EXPLORER and NAUTILUS, keeping the data from ALLEGRO for follow-up studies. With respect to the previous IGEC 1997-2000 observations, the amplitude sensitivity of the detectors to bursts improved by a factor about 3 and the sensitivity bandwidths are wider, so that the data analysis was tuned considering a larger class of detectable waveforms. Thanks to the higher duty cycles of the single detectors, we decided to focus the analysis on three-fold observation, so to ensure the identification of any single candidate of gravitational waves (gw) with high statistical confidence. The achieved false detection rate is as low as 1 per century. No candidates were found.Comment: 10 pages, to be submitted to Phys. Rev.

Measurement of the muon decay spectrum with the ICARUS liquid Argon TPC

Examples are given which prove the ICARUS detector quality through relevant physics measurements. We study the muon decay energy spectrum from a sample of stopping muon events acquired during the test run of the ICARUS T600 detector. This detector allows the spatial reconstruction of the events with fine granularity, hence, the precise measurement of the range and dE/dx of the muon with high sampling rate. This information is used to compute the calibration factors needed for the full calorimetric reconstruction of the events. The Michel rho parameter is then measured by comparison of the experimental and Monte Carlo simulated muon decay spectra, obtaining rho = 0.72 +/- 0.06(stat.) +/- 0.08(syst.). The energy resolution for electrons below ~50 MeV is finally extracted from the simulated sample, obtaining (Emeas-Emc)/Emc = 11%/sqrt(E[MeV]) + 2%.Comment: 16 pages, 8 figures, LaTex, A4. Some text and 1 figure added. Final version as accepted for publication in The European Physical Journal

Feminist phenomenology and the woman in the running body

Modern phenomenology, with its roots in Husserlian philosophy, has been taken up and utilised in a myriad of ways within different disciplines, but until recently has remained relatively under-used within sports studies. A corpus of sociological-phenomenological work is now beginning to develop in this domain, alongside a longer standing literature in feminist phenomenology. These specific social-phenomenological forms explore the situatedness of lived-body experience within a particular social structure. After providing a brief overview of key strands of phenomenology, this article considers some of the ways in which sociological, and particularly feminist phenomenology, might be used to analyse female sporting embodiment. For illustrative purposes, data from an autophenomenographic project on female distance running are also included, in order briefly to demonstrate the application of phenomenology within sociology, as both theoretical framework and methodological approach

Description and performance of MEA, The magnetic detector at adone

Abstract The experimental detector at Adone, MEA, which operates with its magnetic field perpendicular to the e + e − beams is described. Studies of the magnetic compensation for operation at Adone and resulting magnetic fields are presented. Particles are detected and analyzed using narrow-gap and wide-gap spark chambers which are triggered by scintillation and proportional counters. Momentum measurements for charged particles are made with Δ / p / p = ±0.07 at p = 1 Gev/ c ( B = 2.5 kG) and angles are measured to better than ± 1.5° over a solid angle of ∼0.3 × 4 π sr