9 research outputs found

    Alternative Processes for Removing Organic SulfurCompounds from Petroleum Fractions

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    This work discusses the processes for removing sulfur from fuels, and problems related thereto, including conventional and improved processes of hydrodesulfurization, and alternative technologies and processes for obtaining fuel with extremely low sulfur content, which are in the process of research and development. It is anticipated that alternative processes already developed or those being researched will be applied as an addition to the currently most commonly used process of hydrodesulfurization, which is based on selective heterogeneous catalysts. Reviewed are new achievements in the developmentof the hydrodesulfurization process regarding new catalysts and reactors, the research and development possibilities of the adsorption and extraction processes, as well as the biodesulfurization process

    Effect of feeding olive by-products on certain blood parameters and serum enzyme activities of fattening rabbits

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    The effect of feeding different levels (10 and 20%) of dehydrated olive cake pulp on certain blood parameters and on the catalytic activity of serum enzymes was studied in fattening rabbits. A total of 60 rabbits were divided into a control group (C) and two experimental groups (E1, E2), each comprising 10 males and 10 females. Rabbits of Group C received no dehydrated olive cake pulp in their diet, while rabbits of Group E1and Group E2were fed 10% and 20% dehydrated olive cake pulp, respectively. After Day 56 of the experiment, blood samples were obtained by cardiac puncture and certain blood parameters as well as the catalytic activity of serum enzymes were determined. Following the experimental feeding period no significant differences were found between Group C and Groups E1and E2in red blood cell (RBC) and white blood cell (WBC) count, haemoglobin concentration and haematocrit value. Similarly, after 56 days of experimental fattening no significant differences were found between the control group and the experimental groups in the catalytic activity of the serum enzymes alkaline phosphatase (AP), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), and lactate dehydrogenase (LDH). However, Group E2 rabbits manifested a significantly higher alanine aminotransferase (ALT) activity in the serum than did rabbits of Group E1. The results indicate that the inclusion of dehydrated olive cake pulp in the diet at the rate of 10% or 20% caused no changes in the investigated blood parameters and serum enzyme activities of fattening rabbits

    WISE J061213.85-303612.5: a new T-dwarf binary candidate

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    Context. T and Y dwarfs are among the coolest and least luminous objects detected, and they can help to understand the properties of giant planets. Up to now, there are more than 350 T dwarfs that have been identified thanks to large imaging surveys in the infrared, and their multiplicity properties can shed light on the formation process. Aims. The aim of this work is to look for companions around a sample of seven ultracoool objects. Most of them have been discovered by the WISE observatory and have not been studied before for multiplicity. Methods. We observed a sample six T dwarfs and one L9 dwarf with the Laser Guide Star (LGS) and NAOS-CONICA, the adaptive optics (AO) facility, and the near infrared camera at the ESO Very Large Telescope. We observed all the objects in one or more near-IR filters (JHK_s). Results. From the seven observed objects, we have identified a subarcsecond binary system, WISE J0612-3036, composed of two similar components with spectral types of T6. We measure a separation of ρ = 350 ± 5 mas and a position angle of PA = 235 ± 1°. Using the mean absolute magnitudes of T6 dwarfs in the 2MASS JHK_s bands, we estimate a distance of d = 31 ± 6 pc and derive a projected separation of ρ ~ 11 ± 2 au. Another target, WISE J2255-3118, shows a very faint object at 1.̋3 in the K_s image. The object is marginally detected in H, and we derive a near infrared color of H − Ks> 0.1 mag. HST/WFC3 public archival data reveals that the companion candidate is an extended source. Together with the derived color, this suggests that the source is most probably a background galaxy. The five other sources are apparently single, with 3-σ sensitivity limits between H = 19–21 for companions at separations ≥ 0.̋5. Conclusions. WISE 0612-3036 is probably a new T-dwarf binary composed of two T6 dwarfs. As in the case of other late T-dwarf binaries, it shows a mass ratio close to 1, although its projected separation, ~11 au, is larger than the average (~5 au). Additional observations are needed to confirm that the system is bound

    Measuring the ratio of the gas and dust emission radii of protoplanetary disks in the Lupus star-forming region

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    We perform a comprehensive demographic study of the CO extent relative to dust of the disk population in the Lupus clouds, in order to find indications of dust evolution and possible correlations with other properties. We increase up to 42 the number of disks of the region with measured CO and dust sizes (RCOR_{\mathrm{CO}}, RdustR_{\mathrm{dust}}) from observations with the Atacama Large Millimeter/submillimeter Array (ALMA). The sizes are obtained from modeling the 12{^{12}}CO J=21J = 2-1 line emission and continuum emission at 0.89\sim 0.89 mm with an empirical function (Nuker profile or Gaussian function). The CO emission is more extended than the dust continuum, with a R68%COR_{68\%}^{\mathrm{CO}}/R68%dustR_{68\%}^{\mathrm{dust}} median value of 2.5, for the entire population and for a sub-sample with high completeness. 6 disks, around 15%15\% of the Lupus disk population have a size ratio above 4. Based on thermo-chemical modeling, this value can only be explained if the disk has undergone grain growth and radial drift. These disks do not have unusual properties in terms of stellar mass (MM_{\star}), disk mass (MdiskM_{\mathrm{disk}}), CO and dust sizes (RCOR_{\mathrm{CO}}, RdustR_{\mathrm{dust}}), and mass accretion. We search for correlations between the size ratio and MM_{\star}, MdiskM_{\mathrm{disk}}, RCOR_{\mathrm{CO}} and RdustR_{\mathrm{dust}}: only a weak monotonic anti-correlation with the RdustR_{\mathrm{dust}} is found. The lack of strong correlations is remarkable and suggests that the bulk of the population may be in a similar evolutionary stage, independent of the stellar and disk properties. These results should be further investigated, since the optical depth difference between CO and dust continuum may play a role in the inferred size ratios. Lastly, the CO emission for the majority of the disks is consistent with optically thick emission and an average CO temperature of around 30 K.Comment: Accepted for publication on A&A, 14 pages of main text with 5 figures, and 11 pages of appendices A, B, C, D, E and F with 13 figure

    Gljivice kao sastavni dio bioaerosola u nastambama za muzne krave i nesilice konzumnih jaja

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    The air of animal dwellings can contain great amounts of bioaerosol composed of dust, bacteria, fungi, and endotoxins. The composition may depend on animal species, building construction, animal accommodation, and microclimate parameters, to name just a few factors. Pathogens contained may be a serious threat to animal and human health. The aim of our study was to analyse the fungi aerosol content in a stable housing dairy cows and in a coop for laying hens over the three autumn months of 2007. The air was sampled on Petri dishes with Sabouraud glucose agar. After laboratory treatment, we identifi ed the most common fungi. Their count in the stable ranged from 3.98x103 CFU m-3 to 5.11x104 CFU m-3 and in the coop from 6.89 x104 CFU m-3 to 1.13x105 CFU m-3. The difference between the two animal dwellings was statistically different at the level of p<0.05. In both dwellings, the most common were the fungi Aspergillus sp., Penicillium sp., and yeasts, followed by Cladosporium sp., Fusarium sp., Mucor sp., Scopulariopsis sp., Alternaria sp., and Rhizopus sp. Our results are entirely in line with values reported in literature and are at the lower end of the range. They call for further investigation that would eventually lead to setting air quality standards for animal dwellings and to developing reliable monitoring systems in order to ensure safe food and safe environment.U zraku nastambi za držanje životinja stvaraju se znatne količine bioaerosola. Njega čine prašina, bakterije, gljivice, endotoksini i plinovi. Brojnost im ovisi o građevinsko-tehničkim značajkama nastambi, naseljenosti životinjama, načinu držanja, temperaturno-vlažnim odnosima u staji i aktivnostima oko hranjenja, mužnje, skupljanja jaja i drugih poslova. Ove čestice, ako su patogene, mogu biti ozbiljna prijetnja za zdravlje ljudi. Mjerenja su obavljana u staji muznih krava te u objektu za nesilice, 2007. godine, tijekom tri jesenja mjeseca. Zrak je uzorkovan na Petrijeve zdjelice sa Sabouraudovim glukoznim agarom, uređajem MAS 100. Nakon obrade u laboratoriju, prema osnovnim i mikromorfološkim osobinama poraslih kolonija identifi cirani su najčešće zastupljeni rodovi gljivica. Srednja vrijednost broja gljivica u zraku staje za muzne krave kretala se od 3,98x103 CFU m-3 do 5,11x104 CFU m-3. Broj gljivica u zraku objekta za nesilice kretao se od 6,89x104 CFU m-3 do 1,13x105 CFU m-3. Ove vrijednosti statistički su se značajno razlikovale na razini p<0,05. U obje pretraživane nastambe najčešće su bili zastupljeni rodovi Aspergillus, Penicillium i kvasnice. U manjem postotku utvrđene su gljivice iz rodova Cladosporium sp., Fusarium sp., Mucor sp., Scopulariopsis sp., Alternaria sp. i Rhizopus sp. Rezultati ovih istraživanja o kvantitativnom i kvalitativnom sastavu gljivica u zraku pretraženih nastambi potpuno su u skladu s vrijednostima zabilježenim u literaturi te se nalaze na donjim granicama opisanih raspona. Utvrđeni broj i rodovi gljivica ukazuju na nužnost daljnjih istraživanja te potrebu postavljanja standardnih vrijednosti glede kvalitete zraka u nastambama za životinje, kao i razvoj vjerodostojnog sustava praćenja navedenih čimbenika, s ciljem stvaranja sigurne hrane i sigurnog okoliša

    A Design of Experiments Investigation of Adsorptive Desulfurization of Diesel Fuel

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    Adsorptive desulfurization of diesel fuel was investigated applying two Design of Experiments (DOE) methods. The experiments were carried out in a batch adsorption system using Chemviron Carbon SOLCARBTM C3 activated carbon as adsorbent. The first DOE method employed was a full factorial with three factors on two levels and five center points, and the second was Box-Behneken design with the same three factors but on three levels. The effects of individual factors and their interactions on sulfur concentration and sorption capacity were determined, and statistical models of the process developed. The first-order models predict the behavior of the system rather well but significant curvature was detected. Subsequently developed second-order models were able to give reasonably well descriptions of the system. The lowest achieved output sulfur concentration was 7.6 mg kg–1 with relatively low sorption capacity of 0.0861 mg g–1

    Decolorization of the Anthraquinone Dye C. I. Reactive Blue 2 by Fenton Oxidation; Statistical Experimental Design

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    This work presents the results of studies on the decolorization of water solution of anthraquinone dye C. I. Reactive Blue 2 (RB2), which was chosen as the model dye pollutant, using Fenton (Fe2+/H2O2) process. Batch experiments were carried out to investigate the influence of operational parameters which affect the efficiency of Fenton process in RB2 decolorization. The final decolorization obtained with Fenton treatment at 0.0025 mol L-1 H2O2 and 0.0005 mol L-1 Fe2+ (pH = 3; room temperature, θ = 22 ± 1 °C) achieves a dye removal of 100 % for initial RB2 concentration of 100 mg L-1. Experimental data were analyzed with statistical experimental design method using Design of Experiments (DoE) software. Factorial design of experiments was employed to study the effect of three factors, time (2 and 60 min), Fe2+ concentration (0.00005 and 0.0005 mol L-1) and H2O2 concentration (0.0003 and 0.0025 mol L-1) at two levels; low and high. It was found that all three process parameters and their interaction affect the percentage of dye removal
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