Energy recovery from vinery waste: Dust explosion issues

The concern about global warming issues and their consequences is more relevant than ever, and the H2020 objectives promoted by the EU are oriented towards generating climate actions and sustainable development. The energy sector constitutes a difficult challenge as it plays a key role in the global warming impact. Its decarbonization is a crucial factor, and significant efforts are needed to find efficient alternatives to fossil fuels in heating/electricity generation. The biomass energy industry could have a contribution to make in the shift to renewable sources; the quest for a suitable material is basically focused on the energy amount that it stores, its availability, logistical considerations, and safety issues. This work deals with the characterization of a wine-waste dust sample, in terms of its chemical composition, fire behavior, and explosion violence. This material could be efficiently used in energy generation (via direct burning as pellets), but scarce information is present in terms of the fire and explosion hazards when it is pulverized. In the following, the material is analyzed through different techniques in order to clearly understand its ignition sensitivity and fire effects; accelerating aging treatment is also used to simulate the sample storage life and determine the ways in which this affects its flammability and likelihood of explosion

Biomass from winery waste: Evaluation of dust explosion hazards

Food and drink supply chains have significant environmental impacts due to their use of resources, emissions, and waste production. An efficient method to reduce this impact is the valorisation of biomass waste through energy recovery by using it as a source of heat. The European energy system faces several fundamental challenges being currently the largest emitter of greenhouse gases due to its large dependence on fossil fuels (mostly natural gas). Therefore, the energy sector's decarbonization will play a central role in achieving a climateneutral economy in Europe. Identifying the suitable material for biofuel is basically focused on the amount of energy that the material stores, availability, and logistic considerations. Sawdust and wood chips have been extensively used as biofuel in recent years, but other promising raw and waste materials could be adopted (with the positive effect of reducing the impact on forestry soil and the food chain). Novel materials bring consequently novel challenges, also regarding their safe use. As an example, a relevant waste flow is produced from wine manufacturing. A solid with high moisture content is obtained from grapes pressing, and it could be reused to produce distillates. The obtained exhausted pomace could be considered among the materials potentially involved in energy recovery. It is also carrying dust explosion hazard, as solid residues could be present in the form of coarse and fine powders. In this work, grape pomace is examined: its explosion safety-related properties are evaluated to define the severity of events in which this material could be ignited. Minimum Ignition Energy (MIE), explosion pressure peak (Pmax), deflagration severity index (KSt), autoignition temperature (MIT), and Volatile Point (VP) are measured according to standard procedures. This material's thermal susceptibility and ignition sensitivity are studied and compared with biomasses from different sources (ligneo-cellulosic and herbaceous)

GMOS Integral Field Spectroscopy of a Merging System with Enhanced Balmer Absorption

In this paper we present the three dimensional dynamics of the galaxy SDSS J101345.39+011613.66, selected for its unusually strong Balmer absorption lines (Wo(H-delta)=7.5A). Using the GMOS-South IFU in Nod & Shuffle mode we have mapped the continuum and optical absorption lines of this z=0.1055 field galaxy. This galaxy has a disturbed morphology, with a halo of diffuse material distributed asymmetrically toward the north. Using the [OII] emission line (Wo([OII])=4.1A) we find that the gas and hot OB stars are offset from the older stars in the system. The gas also has a spatially extended and elongated morphology with a velocity gradient of 100+/-20km/s across 6kpc in projection. Using the strong H-gamma and H-delta absorption lines we find that the A- stars are widely distributed across the system and are not centrally concentrated arguing that the A-star population has formed in molecular clouds outside the nucleus. By cross correlating the spectra from the datacube with an A-star template we find evidence that the A-star population has a 40km/s shear in the same direction as the gas. The disturbed morphology, strong colour gradients and strong H-delta and H-gamma absorption lines in SDSS J101345.39 argue that this is a recent tidal interaction/merger between a passive elliptical and star-forming galaxy. Although based on a single object, these results show that we can spatially resolve and constrain the dynamics of this short lived (yet important) phase of galaxy formation in which the evolutionary process take galaxies from star-forming to their quiescent end products.Comment: 7 pages, 7 figures. Accepted for publication in Ap

Issues of “Standard” explosion tests for non-spherical dusts

Measurements of the flammability and explosion parameters for non-spherical dusts are performed according to standard procedures in standard explosion equipment developed and tested for spherical dusts. Studies have shown that the standard procedures and equipment applied to spherical particles suffer from many issues: control of the turbulence level, non-uniform dust dispersion, and particle fragmentation due to the injection system. The applicability of the standard procedures and equipment to non-spherical particles is still an open issue. In this work, we have investigated, via CFD simulations, the distribution of turbulence and dust concentration in the standard 20 l spherical vessel for non-spherical particles. Results have shown that a higher turbulence level and a higher amount of dust actually fed into the vessel are reached with respect to spherical particles

Synthetic Spectra and Color-Temperature Relations of M Giants

As part of a project to model the integrated spectra and colors of elliptical galaxies through evolutionary synthesis, we have refined our synthetic spectrum calculations of M giants. After critically assessing three effective temperature scales for M giants, we adopted the relation of Dyck et al. (1996) for our models. Using empirical spectra of field M giants as a guide, we then calculated MARCS stellar atmosphere models and SSG synthetic spectra of these cool stars, adjusting the band absorption oscillator strengths of the TiO bands to better reproduce the observational data. The resulting synthetic spectra are found to be in very good agreement with the K-band spectra of stars of the appropriate spectral type taken from Kleinmann & Hall (1986) as well. Spectral types estimated from the strengths of the TiO bands and the depth of the bandhead of CO near 2.3 microns quantitatively confirm that the synthetic spectra are good representations of those of field M giants. The broad-band colors of the models match the field relations of K and early-M giants very well; for late-M giants, differences between the field-star and synthetic colors are probably caused by the omission of spectral lines of VO and water in the spectrum synthesis calculations. Here, we present four grids of K-band bolometric corrections and colors -- Johnson U-V and B-V; Cousins V-R and V-I; Johnson-Glass V-K, J-K and H-K; and CIT/CTIO V-K, J-K, H-K and CO -- for models having 3000 K < Teff < 4000 K and -0.5 < log g < 1.5. These grids, which have [Fe/H] = +0.25, 0.0, -0.5 and -1.0, extend and supplement the color-temperature relations of hotter stars presented in a companion paper (astro-ph/9911367).Comment: To appear in the March 2000 issue of the Astronomical Journal. 60 pages including 15 embedded postscript figures (one page each) and 6 embedded postscript tables (10 pages total

On the velocity distributions of the one-dimensional inelastic gas

We consider the single-particle velocity distribution of a one-dimensional fluid of inelastic particles. Both the freely evolving (cooling) system and the non-equilibrium stationary state obtained in the presence of random forcing are investigated, and special emphasis is paid to the small inelasticity limit. The results are obtained from analytical arguments applied to the Boltzmann equation along with three complementary numerical techniques (Molecular Dynamics, Direct Monte Carlo Simulation Methods and iterative solutions of integro-differential kinetic equations). For the freely cooling fluid, we investigate in detail the scaling properties of the bimodal velocity distribution emerging close to elasticity and calculate the scaling function associated with the distribution function. In the heated steady state, we find that, depending on the inelasticity, the distribution function may display two different stretched exponential tails at large velocities. The inelasticity dependence of the crossover velocity is determined and it is found that the extremely high velocity tail may not be observable at ``experimentally relevant'' inelasticities.Comment: Latex, 14 pages, 12 eps figure

Conservazione e valorizzazione delle grotte sarde: biodiversit\ue0 e ruolo socio-economico-culturale

Stima del valore economico del bene grotta e individuazione del target di fruitore; studio dei percorsi turistici per ottimizzare il numero dei visitatori per la salvaguardia del bene ambientale grotta, Stima della Capacit\ue0 di Carico turistica. Modello di una ottima fruizione di una grotta modello. Modello complesso di integrazione tra beni culturali, enogastronomici, ambientali e demo-etno-antropologici. Studio e creazione di network degli interessi

A ML-based Approach to Enhance Metrological Performance of Wearable Brain-Computer Interfaces

In this paper, the adoption of Machine Learning (ML) classifiers is addressed to improve the performance of highly wearable, single-channel instrumentation for Brain-Computer Interfaces (BCIs). The proposed BCI is based on the classification of Steady-State Visually Evoked Potentials (SSVEPs). In this setup, Augmented Reality Smart Glasses are used to generate and display the flickering stimuli for the SSVEP elicitation. An experimental campaign was conducted on 20 adult volunteers. Successively, a Leave-One-Subject-Out Cross Validation was performed to validate the proposed algorithm. The obtained experimental results demonstrate that suitable ML-based processing strategies outperform the state-of-the-art techniques in terms of classification accuracy. Furthermore, it was also shown that the adoption of an inter-subjective model successfully led to a decrease in the 3-σ uncertainty: this can facilitate future developments of ready-to-use systems

Accurate estimates of absolute left ventricular volumes from equilibrium radionuclide angiographic count data using a simple geometric attenuation correction

To simplify and clarify the methods of obtaining attenuation-corrected equilibrium radionuclide angiographic estimates of absolute left ventricular volumes, 27 patients who also had biplane contrast cineangiography were evaluated. Background-corrected left ventricular end-diastolic and end-systolic counts were obtained by semiautomated variable and hand-drawn regions of interest and were normalized to cardiac cycles processed, frame rate and blood sample counts. Blood sample counts were acquired on (d°) and at a distance (d′) from the collimator. A simple geometric attenuation correction was performed to obtain absolute left ventricular volume estimates.Using blood sample counts obtained at d° or d′, the attentuation.corrected radionuclide left ventricular end-diastolic volume estimates using both region of interest selection methods correlated with the cineangiographic end-diastolic volumes (r = 0.95 to 0.96). However, both mean radionuclide semiautomated variable left ventricular end-diastolic volumes (179 ± 100 [± 1 standard deviation] and 185 ± 102 ml, p < 0.001) were smaller than the average cineangiographic end-diastolic volume (217 ± 102 ml), and both mean hand-drawn left ventricular end-diastolic volumes (212 ± 104 and 220 ± 106 ml) did not differ from the average cineangiographic end-diastolic volume. Using the blood sample counts obtained at d° or d′, the attenuation-corrected radionuclide left ventricular end-systolic volume estimates using both region of interest selection methods correlated with the cineangiographic end-systolic volumes (r = 0.96 to 0.98). Also, using blood sample counts at d°, the mean radionuclide semiautomated variable left ventricular end-systolic volume (116 ± 98 ml, p < 0.05) was less than the average cineangiographic end-systolic volume (128 ± 98 ml), and the other radionuclide end-systolic volumes did not differ from the average cineangiographic end-systolic volume.Therefore, it is concluded that: 1) a simple geometric attenuation-correction of radionuclide left ventricular end-diastolic and end-systolic count data provides accurate estimates of biplane cineangiographic end-diastolic and end-systolic volumes; and 2) the hand-drawn region of interest selection method, unlike the semiautomated variable method that underestimates end-diastolic and end-systolic volumes, provides more accurate estimates of biplane cineangiographic left ventricular volumes irrespective of the distance blood sample counts are acquired from the collimator

Ergodicity criteria for non-expanding transformations of 2-adic spheres

In the paper, we obtain necessary and sufficient conditions for ergodicity (with respect to the normalized Haar measure) of discrete dynamical systems $$ on 2-adic spheres $\mathbf S_{2^{-r}}(a)$ of radius $2^{-r}$, $r\ge 1$, centered at some point $a$ from the ultrametric space of 2-adic integers $\mathbb Z_2$. The map $f\colon\mathbb Z_2\to\mathbb Z_2$ is assumed to be non-expanding and measure-preserving; that is, $f$ satisfies a Lipschitz condition with a constant 1 with respect to the 2-adic metric, and $f$ preserves a natural probability measure on $\mathbb Z_2$, the Haar measure $\mu_2$ on $\mathbb Z_2$ which is normalized so that $\mu_2(\mathbb Z_2)=1$