355 research outputs found
High hydrogen yield and purity from palm empty fruit bunch and pine pyrolysis oils
The benefits of CO 2 sorption enhanced steam reforming using calcined dolomite were demonstrated for the production of hydrogen from highly oxygenated pyrolysis oils of the agricultural waste palm empty fruit bunches (PEFB) and pine wood. At 1 atm in a down-flow packed bed reactor at 600 °C, the best molar steam to carbon ratios were between 2 and 3 using a Ni catalyst. After incorporating steam-activated calcined dolomite as the CO 2 sorbent in the reactor bed, the H 2 yield from the moisture free PEFB oil increased from 9.5 to 10.4 wt.% while that of the pine oil increased from 9.9 to 13.9 wt.%. The hydrogen purity also rose from 68 to 96% and from 54 to 87% for the PEFB and pine oils respectively, demonstrating very substantial sorption enhancement effects
Quantum fluctuations in radiation dominated anisotropic cosmology
Using the metric conformal transformation and simple path integral, Feynman propagator method, for computing its quantum fluctuations, we analyse the radiation dominated anisotropic Bianchi Type I cosmology. We proceed to show that the quantum conformal fluctuations diverge at the classical spacetime singularity, suggesting that a singularity free solution can exist in anisotropic cosmology in the quantum regime
Non-conformal fluctuations in radiation dominated Anisotropic cosmology
Using simple path integral, Feynman propagator method and the relation between conformal time η and scale factor τ, we investigate the non-conformal quantum fluctuations (of expansion and shear) and axisymmetric singularity case in radiation dominated anisotropic cosmology. We show that near the classical singularity the quantum fluctuations tend to diverge
Implementation of ROSA radio occultation data handling into EUMETSAT and GRAS SAF processing
Within this contribution, outcomes from a GRAS - SAF Visiting Scientist activity focused on the analysis of ROSA data quality for their use in operational weather forecasting will be described and main results will be shown. The ROSA Radio Occultation instrument has been developed by Thales-Alenia-Space, Italy and was funded by the Italian Space Agency (ASI). Such instrument is actually flying on-board three opportunity missions: the Indian OCEANSAT-2, the Argentinean SAC-D and the Indian-French MEGATROPIQUES. Focus of this Visiting Scientist activity has primarily been the analysis of ROSA data from OCEANSAT-2.This activity was divided into two parts. In the first one, performed at EUMETSAT, ROSA data processing was implemented into the EUMETSAT YAROS processor. The required updates into such processing package were implemented in order to make it able to properly manage also ROSA raw observations. It has to be noted that this processor is the baseline for the operational next generation EUMETSAT Radio Occultation ground segment: any changes performed in the framework of YAROS can easily be transferred to the operational ground segment. The YAROS - EUMETSAT processor was then updated and adapted to work with the ROSA raw data, tracking frequencies and instrument database. Adaptation to open loop data, navigation bits acquisition and potentially ionospheric measurement will be performed in the next future. NetCDF-4 YAROS output files are phases, amplitudes, bending angles over impact parameter, along with all other required data. Robust bias and standard deviation of bending angles to ECMWF collocated data were the statistical indicators generated to evaluate the quality of the ROSA observations. The second part of the activity was the adaptation of the GRAS-SAF ROPP (Radio Occultation Processing Package) processor for ROSA data processing. This second part was performed at Danish Meteorological Institute and has been focused on bending angles, refractivity and higher level product generation and validation against ECMWF and co-located occultation profiles. For the first time, one month of ROSA data have been deeply analyzed by a state-of-the-art Radio Occultation processing software and results will be described in the framework of this contributio
Design of a structurally optimized bioinspired structural arrangement of a polymer composite wing
Developing trends in designing and manufacturing products made of polymer composite materials allow us to create previously unattainable structures. These include bioinspired structural layouts inspired by objects of nature, for example, the wings of insects, plants, and others. In turn, the structural layout of the wings of aircraft has reached its limit in terms of optimization in its classic form. The work is devoted to an urgent task –the choice of a bioinspired layout for an aircraft wing. A comparison of classic structural arrangement with a bioinspired structure is carried out. The total number of options considered is 14. The structure of the bioinspired wing was chosen based on the action of the load and stress distribution according to the results of preliminary calculations inspired by insect wings. The advantage of wings of a bioinspired design over classical ones by weight up to 32% is shown. The results of the initial stage of studies of bioinspired wings are presented
Effetto dei parametri di trattamento termico sull’arricchimento superficiale di rame in un acciaio 20 Mn4
Il fenomeno “HOT-SHORTNESS” affligge principalmente gli acciai prodotti con forno ad arco elettricoed è causato dal residuo di rame presente nel rottame impiegato per la produzione.Esso, infatti, è responsabile della formazione di cricche superficiali durante le lavorazioni di forgiatura elaminazione a caldo. Scopo del presente lavoro è indagare il comportamento del rame in un acciaio 20Mn4contenente il 0.33% di Cu, sottoponendo il materiale a cicli di trattamenti termici. Sono stati indagatiparametri quali temperatura e tempo di mantenimento, al fine di ottimizzare il processo, ridurre la formazionedi agglomerati di Cu in posizione intergranulare, e ottenere così le condizioni di processo utilialla diminuzione della difettosità superficiale dell’acciaio trattato. Sono perciò stati eseguiti sul materialediversi trattamenti termici in atmosfera, nel campo di lavorabilità a caldo dell’acciaio, variando duratadel trattamento e temperatura di mantenimento. A conclusione del lavoro sono state individuate le condizionidi trattamento idonee all’ottenimento di un acciaio con ridotta difettosità superficiale, escludendo l’interventosulla composizione chimica del materiale e dell’atmosfera impiegata nel forno
Investigation of lipophilic substances of the leaves and flowers of spindle tree (Euonymus Europaea L.)
Spindle Tree (Euonymus europaea L.) has long been used in folk medicine for the treatment of dermatomycoces and as an antiparasitic and anthelmintic agent. However, with what substances it is associate this activity, it is not known for certain. In a previous work, a was developed extracting scheme from the bark of Spindle Tree (Euonymus europaea L.) to obtain water-soluble and lipophilic substances and the composition of the lipophilic fraction was studied using the GC-MS method.
The purpose of this work was to obtain lipophilic substances from the flowers and leaves of Spindle Tree and to compare their chemical composition with the composition of substances obtained from the bark of the plant.
Flowers and leaves were dried in a drying oven at a temperature of 52 °C, after which a fraction of lipophilic substances was obtained by extraction with petroleum ether. This fraction was analyzed using gas chromatography-mass spectrometry (GC-MS). For this, a chromatographic column was used, which was washed with methanol (model NR-5ms, length 30 m, diameter 0.25 mm, filler: 95% dimethylpolysiloxane + 5% diphenylpolysiloxane; carrier gas ‒ helium with a constant flow of 1.5 ml/min) and 6C / MS Agilent Technologies 6890 N / 5975 B mass spectrometer (USA).
The etxtraction by petroleum ether was obtained fraction of lipophilic substances in the amount of 0.83% of the taken weight of dried flowers and 0.62% by weight of dried leaves. In total, 28 compounds were detected in flowers, and 19 in leaves. It was established that flowers and leaves of Spindle Tree, like bark, are characterized by a high content of paraffinic carbohydrates (from C20H42 to C31H64). Their content is higher in flowers (more than 50% of the composition of the fraction), and in leaves and bark ≈ 35%. Steroid and terpene compounds in the lipophilic fractions of the leaves and bark of the plant are respectively 28.26% and 24.32%. Among them quantitatively dominated by freedeen. A rather high content of squalene (2.06%) was found in the leaves of the plant. Among other compounds, a significant proportion of fatty acids and their esters, of which 24.59% by weight of the lipophilic fraction of flowers and 14.74% by weight of the lipophilic fraction of leaves.
An analysis of the results indicates a greater promise for the use in medicine of lipophilic substances of the bark and leaves of Spindle Tree than of flowers
Elastic scattering losses in the four-wave mixing of Bose Einstein Condensates
We introduce a classical stochastic field method that accounts for the
quantum fluctuations responsible for spontaneous initiation of various atom
optics processes. We assume a delta-correlated Gaussian noise in all initially
empty modes of atomic field. Its strength is determined by comparison with the
analytical results for two colliding condensates in the low loss limit. Our
method is applied to the atomic four wave mixing experiment performed at MIT
[Vogels {\it et. al.}, Phys. Rev. Lett. {\bf 89}, 020401, (2002)], for the
first time reproducing experimental data
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