6,556 research outputs found
Algae-based biorefinery concept. An LCI analysis for a theoretical plant
Both micro and macro algae have a potential to be a valuable feedstock for biorefineries. The theoretical impact assessment of this kind of plant can be carried out through an LCA, which is a key tool in order to evaluate the potential environmental impact of a process throughout its entire life cycle. Hence, it is a priority to perform an LCI with the aim of gathering all the data and simulating all the unit process of a theoretical biorefinery. The Inventory ensures to obtain a simple and immediate way to represent several aspects of a biorefinery, e.g. productivity, environmental pressures, required resources in terms of raw materials and energy. One of the main aspects clearly shown in this study is the significant environmental pressures due to the cultivation and harvesting steps, for which it is desirable to consider a biomass collection from the environment, especially from areas where eutrophication phenomena are particularly recurrent. Another conclusion drawn from the study is that the total plant production per year appears very limited, if compared to any conventional refinery. The following approach can also provide a starting data set to perform a first approximate economic analysis of the costs/gains of the outlined project, and it could be used as a first concept design for the project development of a real plant
Operator solutions for fractional Fokker-Planck equations
We obtain exact results for fractional equations of Fokker-Planck type using
evolution operator method. We employ exact forms of one-sided Levy stable
distributions to generate a set of self-reproducing solutions. Explicit cases
are reported and studied for various fractional order of derivatives, different
initial conditions, and for different versions of Fokker-Planck operators.Comment: 4 pages, 3 figure
Study of peripheral bone mineral density in patients with diffuse idiopathic skeletal hyperostosis
First observation and measurement of the resonant structure of the lambda_b->lambda_c pi-pi+pi- decay mode
We present the first observation of the lambda_b->lambda_c pi-pi+pi- decay
using data from an integrated luminosity of approximately 2.4 fb-1 of ppbar
collisions at ECM=1.96 TeV, collected with the CDF II detector at the Fermilab
Tevatron. We also present the first observation of the resonant decays
lambda_b->sigma_c(2455)0 pi+pi- ->lambda_c pi-pi+pi-, lambda_b->sigma_c(2455)++
pi-pi- ->lambda_c pi-pi+pi-, lambda_b->lambda_c(2595)+ pi- ->lambda_c pi-pi+pi-
and lambda_b->lambda_c(2625)+ pi- ->lambda_c pi-pi+pi-, and measure their
relative branching ratios.Comment: 3 pages, 3 figures, to appear in the proceedings of LEPTON PHOTON
2009, Hamburg, German
Simulation of blind pre-diction and post-diction shaking table tests on a masonry building aggregate using a continuum modelling approach
Masonry buildings of historical centres are usually organized within aggregates, whose structural performance against seismic actions is challenging to predict and constitutes still an open issue. The SERA-AIMS (Seismic Testing of Adjacent Interacting Masonry Structures) project was developed to provide additional experimental data by testing a half-scale, two-unit stone masonry aggregate subjected to two horizontal components of dynamic excitation. In this context, this paper investigates the reliability of the modelling approach and the assumptions adopted to generate a three-dimensional continuum finite element model. The work involves two stages, namely a blind pre-diction and a post-diction phase, and proposes a series of simulation analyses including a strategy to shorten the actual records and save computation costs. The study was performed to investigate the extent of uncertainty in modelling for such masonry aggregates in relation to the experimental outcomes. Pre-diction results were proven to be not accurate in terms of predicted displacements and damage patterns. The upgrades introduced for the post-diction analyses, including the calibration of the elastic modulus and the introduction of a non-linear interface between the two units, allowed to improve the outcomes, with reasonable results in terms of predicted base shear force, displacements along Y-direction and damage pattern for the non-linear stage. The overall approach showed to be appropriate for the structural analysis of existing masonry aggregates, but the accurate modelling of this type of structure remains challenging due to the high level of uncertainties
Influence of wall-to-floor connections and pounding on pre- and post-diction simulations of a masonry building aggregate tested on a shaking table
This paper presents numerical simulations within the frame of the project SERA-AIMS (Seismic Testing of Adjacent Interacting Masonry Structures). The study includes blind pre-diction and post-diction stages. The former was developed before performing the shaking table tests at the laboratory facilities of LNEC (Lisbon), while the latter was carried out once the test results were known. For both, three-dimensional finite element models were prepared following a macro-modelling approach. The structure consisted of a half-scaled masonry aggregate composed by two units with different floor levels. Material properties used for the pre-diction model were based on preliminary tests previously provided to the participants. The masonry constitutive model used for the pre-diction study reproduced classical stress-strain envelope, whereas a more refined model was adopted for the post-diction. After eigenvalue analysis, incremental nonlinear time history analysis was performed under a unique sequence based on the given load protocol to account for damage accumulation. In the post-diction, the numerical model was calibrated on the data recorded during the shaking table tests and nonlinear dynamic analysis repeated under the recorded accelerogram sequence. The interaction between the two units was simulated through interface elements. Moreover, the timber floors were accounted following different strategies: not modelling or considering nonlinear wall-to-floor connections. Advantages and disadvantages are then analysed, comparing the pre-diction and post-diction results with the experimental data. Numerical results differ from the experimental outcomes regarding displacements and interface pounding, although a clear improvement is visible in the post-diction model
Functional shoe for the detection of walking pattern anomalies
Analysis of walking patterns can play an important role in the diagnosis of musculoskeletal disorder and detecting anomalies in walking gaits. In this work, we introduce a systematic approach to detect person's walking patterns. A flexible resistive pressure sensor, developed from electro-conductive textile fabric, is non-intrusively integrated in an ordinary shoe together with a time of flight height sensor. The constructed shoe detects both the pressure between shoe and foot and the gap between shoe and ground. The combination of those give a trace of the walking pattern. The shoe should be functional in detecting walking pattern anomalies
Beam test calibration of the balloon-borne imaging calorimeter for the CREAM experiment
CREAM (Cosmic Ray Energetics And Mass) is a multi-flight balloon mission
designed to collect direct data on the elemental composition and individual
energy spectra of cosmic rays. Two instrument suites have been built to be
flown alternately on a yearly base. The tungsten/Sci-Fi imaging calorimeter for
the second flight, scheduled for December 2005, was calibrated with electron
and proton beams at CERN. A calibration procedure based on the study of the
longitudinal shower profile is described and preliminary results of the beam
test are presented.Comment: 4 pages, 4 figures. To be published in the Proceedings of 29th
International Cosmic Ray Conference (ICRC 2005), Pune, India, August 3-10,
200
INFN Camera demonstrator for the Cherenkov Telescope Array
The Cherenkov Telescope Array is a world-wide project for a new generation of
ground-based Cherenkov telescopes of the Imaging class with the aim of
exploring the highest energy region of the electromagnetic spectrum. With two
planned arrays, one for each hemisphere, it will guarantee a good sky coverage
in the energy range from a few tens of GeV to hundreds of TeV, with improved
angular resolution and a sensitivity in the TeV energy region better by one
order of magnitude than the currently operating arrays. In order to cover this
wide energy range, three different telescope types are envisaged, with
different mirror sizes and focal plane features. In particular, for the highest
energies a possible design is a dual-mirror Schwarzschild-Couder optical
scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based
camera is being proposed as a solution to match the dimensions of the pixel
(angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made
by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the
focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near
UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a
Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer,
self-trigger and on-demand digitization capabilities specifically developed for
this purpose. The pixel dimensions of mm lead to a very compact
design with challenging problems of thermal dissipation. A modular structure,
made by copper frames hosting one PSM and the corresponding FEE, has been
conceived, with a water cooling system to keep the required working
temperature. The actual design, the adopted technical solutions and the
achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
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