Random error propagation and uncertainty analysis in the dynamic characterization of Tilting Pad Journal Bearings

In this work a new statistical method for the determination of the dynamic coefficients of Tilting Pad Journal Bearings is described. The method is applied to the results obtained testing a 5 pads tilting pad journal bearing with 280 mm diameter. Tests were performed on an advanced experimental apparatus specifically realized for investigations on large size high performance bearings for turbomachinery. The linear coefficient identification procedure is based on the dynamic measurement of forces, accelerations and relative displacements of rotor and bearing, as function of excitation frequency for different operating conditions. The post-processing of the dynamic data is performed in the frequency domain using the Fast Fourier Transform. Along with a description of the experimental test and identification procedure, this paper presents a least-square minimization technique for determining the dynamic coefficients and a bootstrap statistical technique for estimating their confidence intervals

The stochastic quantization method and its application to the numerical simulation of volcanic conduit dynamics under random conditions

Stochastic Quantization (SQ) is a method for the approximation of a continuous probability distribution with a discrete one. The proposal made in this paper is to apply this technique to reduce the number of numerical simulations for systems with uncertain inputs, when estimates of the output distribution are needed. This question is relevant in volcanology, where realistic simulations are very expensive and uncertainty is always present. We show the results of a benchmark test based on a one-dimensional steady model of magma flow in a volcanic conduit

error analysis in the determination of the dynamic coefficients of tilting pad journal bearings

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Production of Secondary Organic Aerosol During Aging of Biomass Burning Smoke From Fresh Fuels and Its Relationship to VOC Precursors

After smoke from burning biomass is emitted into the atmosphere, chemical and physical processes change the composition and amount of organic aerosol present in the aged, diluted plume. During the fourth Fire Lab at Missoula Experiment, we performed smog-chamber experiments to investigate formation of secondary organic aerosol (SOA) and multiphase oxidation of primary organic aerosol (POA). We simulated atmospheric aging of diluted smoke from a variety of biomass fuels while measuring particle composition using high-resolution aerosol mass spectrometry. We quantified SOA formation using a tracer ion for low-volatility POA as a reference standard (akin to a naturally occurring internal standard). These smoke aging experiments revealed variable organic aerosol (OA) enhancements, even for smoke from similar fuels and aging mechanisms. This variable OA enhancement correlated well with measured differences in the amounts of emitted volatile organic compounds (VOCs) that could subsequently be oxidized to form SOA. For some aging experiments, we were able to predict the SOA production to within a factor of 2 using a fuel-specific VOC emission inventory that was scaled by burn-specific toluene measurements. For fires of coniferous fuels that were dominated by needle burning, volatile biogenic compounds were the dominant precursor class. For wiregrass fires, furans were the dominant SOA precursors. We used a POA tracer ion to calculate the amount of mass lost due to gas-phase oxidation and subsequent volatilization of semivolatile POA. Less than 5% of the POA mass was lost via multiphase oxidation-driven evaporation during up to 2 hr of equivalent atmospheric oxidation

Identification and quantification of gaseous organic compounds emitted from biomass burning using two-dimensional gas chromatography/time-of-flight mass spectrometry

The current understanding of secondary organic aerosol (SOA) formation within biomass burning (BB) plumes is limited by the incomplete identification and quantification of the non-methane organic compounds (NMOCs) emitted from such fires. Gaseous organic compounds were collected on sorbent cartridges during laboratory burns as part of the fourth Fire Lab at Missoula Experiment (FLAME-4), with analysis by two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC/TOFMS). The sensitivity and resolving power of GC×GC/TOFMS allowed the acquisition of the most extensive data set of BB NMOCs to date, with measure ments for 722 positively or tentatively identified compounds. Estimated emission factors (EFs) are presented for these compounds for burns of six different vegetative fuels, including conifer branches, grasses, agricultural residue, and peat. The number of compounds detected from individual burns ranged from 129 to 474, and included extensive isomer groups. For example, 38 monoterpene isomers were observed in the emissions from coniferous fuels; the isomeric ratios were found to be consistent with those reported in relevant essential oils, suggesting that the composition of such oils may be very useful when predicting fuel-dependent terpene emissions. Further, eleven sesquiterpenes were detected and tentatively identified, providing the first reported speciation of sesquiterpenes in gas-phase BB emissions. The calculated EFs for all measured compounds are compared and discussed in the context of potential SOA formation

Identification and quantification of gaseous organic compounds emitted from biomass burning using two-dimensional gas chromatography–time-of-flight mass spectrometry

The current understanding of secondary organic aerosol (SOA) formation within biomass burning (BB) plumes is limited by the incomplete identification and quantification of the non-methane organic compounds (NMOCs) emitted from such fires. Gaseous organic compounds were collected on sorbent cartridges during laboratory burns as part of the fourth Fire Lab at Missoula Experiment (FLAME-4) and analyzed by two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-ToFMS). The sensitivity and resolving power of GC x GC-ToFMS allowed the acquisition of the most extensive data set of BB NMOCs to date, with measurements from 708 positively or tentatively identified compounds. Estimated emission factors (EFs) are presented for these compounds for burns of six different vegetative fuels, including conifer branches, grasses, agricultural residue, and peat. The number of compounds meeting the peak selection criteria ranged from 129 to 474 among individual burns, and included extensive isomer groups. For example, 38 monoterpene isomers were observed in the emissions from coniferous fuels; the isomeric ratios were found to be consistent with those reported in relevant essential oils, suggested that the composition of such oils may be very useful when predicting fuel-dependent terpene emissions. Further, 11 sesquiterpenes were deteched and tentatively identified, providing the first reported speciation of sesquiterpenes in gas-phase BB emissions. The calculated EFs for all measured compounds are compared and discussed in the context of potential SOA formation

The Winckelmann300 Project: Dissemination of Culture with Virtual Reality at the Capitoline Museum in Rome

The best way to disseminate culture is, nowadays, the creation of scenarios with virtual and augmented reality that supply the visitors of museums with a powerful, interactive tool that allows to learn sometimes difficult concepts in an easy, entertaining way. 3D models derived from reality-based techniques are nowadays used to preserve, document and restore historical artefacts. These digital contents are also powerful instrument to interactively communicate their significance to non-specialist, making easier to understand concepts sometimes complicated or not clear. Virtual and Augmented Reality are surely a valid tool to interact with 3D models and a fundamental help in making culture more accessible to the wide public. These technologies can help the museum curators to adapt the cultural proposal and the information about the artefacts based on the different type of visitor’s categories. These technologies allow visitors to travel through space and time and have a great educative function permitting to explain in an easy and attractive way information and concepts that could prove to be complicated. The aim of this paper is to create a virtual scenario and an augmented reality app to recreate specific spaces in the Capitoline Museum in Rome as they were during Winckelmann’s time, placing specific statues in their original position in the 18th century