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Miren P. Cajaraville - One of the best experts on this subject based on the ideXlab platform.
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Responses of conventional and molecular biomarkers in turbot Scophthalmus maximus exposed to Heavy Fuel Oil no. 6 and styrene.
Aquatic Toxicology, 2012Co-Authors: Pamela Ruiz, Stéphane Le-floch, Michael Theron, Maren Ortiz-zarragoitia, Amaia Orbea, Miren P. CajaravilleAbstract:Abstract Several accidental spills in European coastal areas have resulted in the release of different toxic compounds into the marine environment, such as Heavy Fuel Oil type no. 6 in the “Erika” and “Prestige” Oil spills and the highly toxic styrene after the loss of the “Ievoli Sun”. There is a clear need to develop tools that might allow assessing the biological impact of these accidental spills on aquatic organisms. The aim of the present study was to determine the short-term effects and recovery after exposure of juvenile fish ( Scophthalmus maximus ) to Heavy Fuel Oil no. 6 and styrene by using a battery of molecular, cell and tissue level biomarkers. Turbots were exposed to styrene for 7 days and to the diluted soluble fraction of the Oil (10%) for 14 days, and then allowed to recover in clean seawater for the same time periods. cyp1a1 transcript was overexpressed in turbots after 3 and 14 days of exposure to Heavy Fuel Oil, whereas ahr transcription was not modulated after Heavy Fuel Oil and styrene exposure. pparα transcription level was significantly up-regulated after 3 days of treatment with styrene. Liver activity of peroxisomal acyl-CoA oxidase (AOX) was significantly induced after 14 days of Oil exposure, but it was not affected by styrene. Hepatocyte lysosomal membrane stability (LMS) was significantly reduced after exposure to both treatments, indicating that the tested compounds significantly impaired fish health. Both AOX and LMS values returned to control levels after the recovery period. No differences in gamete development were observed between Fuel- or styrene- exposed fish and control fish, and vitellogenin plasma levels were low, suggesting no xenoestrogenic effects of Fuel Oil or styrene. While styrene did not cause any increase in the prevalence of liver histopathological alterations, prevalence of extensive cell vacuolization increased after exposure to Heavy Fuel Oil for 14 days. In conclusion, the suite of selected biomarkers proved to be useful to determine the early impact of and recovery from exposure to tested compounds in turbot.
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Transcriptional responses of cancer-related genes in turbot Scophthalmus maximus and mussels Mytilus edulis exposed to Heavy Fuel Oil no. 6 and styrene
Ecotoxicology, 2012Co-Authors: Pamela Ruiz, Amaia Orbea, Jeanette M. Rotchell, Miren P. CajaravilleAbstract:Recent spills in European waters have released polycyclic aromatic hydrocarbons, important components of Heavy Fuel Oil, and the hydrocarbon styrene. Heavy Fuel Oil and styrene are classified as potentially genotoxic and carcinogenic. Here we investigate transcription of genes involved in cancer development in the liver of juvenile turbots and in the digestive gland of mussels exposed to Heavy Fuel Oil and to styrene and after a recovery period. In turbot, Oil produced a significant up-regulation of p53 and gadd45α after 14 days exposure. cyclin G1 was up-regulated after 7 days treatment with styrene. In mussels, ras was down-regulated in both treatments after the recovery periods. No mutations in ras hotspots were detected in exposed mussels. gadd45α was up-regulated after the recovery period of the styrene experiment. Overall, transcriptional responses differed in mussels compared to turbot. Turbot responded to hydrocarbon exposure by triggering cell cycle arrest ( p53 ) and DNA repair ( gadd45α ).
Antonio Diegomarin - One of the best experts on this subject based on the ideXlab platform.
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an experimental study of the effect of water content on combustion of Heavy Fuel Oil water emulsion droplets
Combustion and Flame, 2001Co-Authors: Rene Ocampobarrera, Rafael Villasenor, Antonio DiegomarinAbstract:Experiments of isolated high asphaltene droplets of Heavy Fuel Oil/water emulsion were performed to investigate the non-steady behavior of the burning droplets. High-resolution video methods allowed monitoring of the various combustion stages. A highly radiant (1000 °C/s) oxidizing environment was necessary to enhance the volatility differential of the high asphaltene Fuel, thus reducing uncertainties because of the presence of the fiber. Data on size and temperature histories were obtained and coke residues were analyzed by a Scanning Electron Microscope. A lower and upper bound for ignition time delay was established. The error defined as the time lag between these two limits never exceeded 10 ms, which is the maximum time for soot to form in the flame after actual ignition. The ignition time delay of emulsions was longer than for an ordinary Heavy Fuel Oil (HFO) droplets of the same size. The peak temperature of emulsions occurred much earlier in time. The steeper temperature rise seen in the emulsions for portions of their combustion history is evidence of both soot reduction and the extent of burnout of the cenospheres, which is an important aspect in the reduction of pollutant emissions. The occurrence of swelling, disruptive bOiling, splashing and the formation of coke were clearly identified by three characteristic combustion times. The emulsion droplets showed swellings of considerable magnitude relative to that of HFO. Coking of the solid phase took place by a dramatic eruption during the last moments of the droplet lifetime when the molecular structure of the cenosphere appeared to be molded. Coke particles formed from emulsions were more void with thinner and fragile shells suggesting that an amorphous-like molecular structure could have developed as opposed to the more compact shell structure observed for HFO residues, which were harder and more reticent to burning. Excess burnout time or the ratio of burnout time of the emulsions was dependent on the water concentration, indicating that less oxidation time was required for coke particles from emulsions than from Heavy Fuel Oil.
William L Roberts - One of the best experts on this subject based on the ideXlab platform.
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Environmental Challenges and Opportunities in Marine Engine Heavy Fuel Oil Combustion
Lecture Notes in Civil Engineering, 2019Co-Authors: Abdul Gani Abdul Jameel, William L Roberts, Ayman El-baz, Abdulrahman Alkhateeb, Selvedin Telalovic, S. Mani SarathyAbstract:Heavy Fuel Oil (HFO) has been used as Fuel to propel marine engines for over half a century. HFO combustion results in the release of particulate matter like smoke, cenospheres, and ash, and the high sulfur content in HFO results in sulfur dioxide emissions. The use of HFO has resulted in deleterious effects on the environment and on human health. As a result, the International Maritime Organization (IMO) has placed a complete ban on its use on ships in the Antarctic waters to preserve the ecosystem from harm; by 2020, this regulation could be extended to the rest of the world. In the present work, the environmental challenges associated with HFO combustion in the form of gaseous emissions like CO2, CO, SO2, and NO were analyzed using TGA-FTIR technique. Particulate emission like cenosphere formation during HFO combustion was also studied by employing HFO droplet combustion experiments. The influence of asphaltenes, which are notorious for negatively impacting HFO combustion and are responsible for cenosphere formation, was also studied. Strategies like desulfurization, asphaltene removal, and gasification were proposed to help reduce the environmental impact of ships powered by HFO.
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Cenosphere Formation during Single-Droplet Combustion of Heavy Fuel Oil
Energy & Fuels, 2019Co-Authors: Long Jiang, Paolo Guida, Ayman El-baz, Saeed M. Al-noman, Ibrahim A. Alghamdi, Saumitra Saxena, William L RobertsAbstract:The current study aims to investigate cenosphere formation during single-droplet combustion of Heavy Fuel Oil (HFO). A droplet generator was developed to produce freely falling monodisperse droplets uniformly. With the aid of high-speed imaging, droplet diameter was verified to be well controlled within the range of 390–698 μm, and droplets spacing distance was sufficient to avoid droplet–droplet interactions. Impacts of operation conditions (initial HFO droplet size, temperature, and air co-flow rate) and asphaltene content on cenosphere formation in a drop tube furnace were then investigated. Three types of cenosphere morphology were observed by field emission scanning electron microscopy (SEM), namely, larger hollow globules, medium porous cenospheres, and smaller cenospheres with a perfectly spherical and smooth structure. The SEM results show that the mean diameter of collected cenospheres increased as initial droplet size and asphaltene content increased, while it decreased as temperature and air co...
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Influence of Asphaltene Concentration on the Combustion of a Heavy Fuel Oil Droplet
Energy & Fuels, 2018Co-Authors: Abdulrahman A. Khateeb, Paolo Guida, William L RobertsAbstract:Heavy Fuel Oils consist of a blend of middle distillates, mainly diesel Fuel, and Heavy Oil residuals. Varying the fraction of the mixture changes the weight percentage of the asphaltene in the Heavy Fuel Oil (HFO) sample. Asphaltene is a very high molecular weight complex component in the Fuel that increases the Fuel viscosity, surface tension, and chemical reaction rate. Here, we investigate the influence of high asphaltene concentration on the combustion of a single HFO droplet. In this experimental work, we used the thermogravimetric analysis (TGA) and the suspended droplet techniques. We tested HFO samples containing asphaltene at 8, 16, 24 wt % (HFO8, HFO16, and HFO24). The TGA result shows a residual amount of approximately 2.4 wt % of HFO24 compared to no residuals for HFO8 at the end of the process. The suspended droplet technique results reveal the following seven consecutive burning stages for the entire burning process of the liquid and solid phases: (1) preheating, (2) flame startup, (3) inne...
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New Procedure to Develop Lumped Kinetic Models for Heavy Fuel Oil Combustion
Energy & Fuels, 2016Co-Authors: William L Roberts, H.g. ImAbstract:A new procedure to develop accurate lumped kinetic models for complex Fuels is proposed, and applied to the experimental data of the Heavy Fuel Oil measured by thermogravimetry. The new procedure is based on the pseudocomponents representing different reaction stages, which are determined by a systematic optimization process to ensure that the separation of different reaction stages with highest accuracy. The procedure is implemented and the model prediction was compared against that from a conventional method, yielding a significantly improved agreement with the experimental data.
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tg dtg ft icr mass spectrometry and nmr spectroscopy study of Heavy Fuel Oil
Energy & Fuels, 2015Co-Authors: Ayman Elbaz, Abdul Gani, Nadim Hourani, Abdulhamid Emwas, Mani S Sarathy, William L RobertsAbstract:There is an increasing interest in the comprehensive study of Heavy Fuel Oil (HFO) due to its growing use in furnaces, bOilers, marines, and recently in gas turbines. In this work, the thermal combustion characteristics and chemical composition of HFO were investigated using a range of techniques. Thermogravimetric analysis (TGA) was conducted to study the nonisothermal HFO combustion behavior. Chemical characterization of HFO was accomplished using various standard methods in addition to direct infusion atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry (APCI-FTICR MS), high resolution 1H nuclear magnetic resonance (NMR), 13C NMR, and two-dimensional heteronuclear multiple bond correlation (HMBC) spectroscopy. By analyzing thermogravimetry and differential thermogravimetry (TG/DTG) results, three different reaction regions were identified in the combustion of HFO with air, specifically, low temperature oxidation region (LTO), Fuel deposition (FD), and hig...
Pamela Ruiz - One of the best experts on this subject based on the ideXlab platform.
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Responses of conventional and molecular biomarkers in turbot Scophthalmus maximus exposed to Heavy Fuel Oil no. 6 and styrene.
Aquatic Toxicology, 2012Co-Authors: Pamela Ruiz, Stéphane Le-floch, Michael Theron, Maren Ortiz-zarragoitia, Amaia Orbea, Miren P. CajaravilleAbstract:Abstract Several accidental spills in European coastal areas have resulted in the release of different toxic compounds into the marine environment, such as Heavy Fuel Oil type no. 6 in the “Erika” and “Prestige” Oil spills and the highly toxic styrene after the loss of the “Ievoli Sun”. There is a clear need to develop tools that might allow assessing the biological impact of these accidental spills on aquatic organisms. The aim of the present study was to determine the short-term effects and recovery after exposure of juvenile fish ( Scophthalmus maximus ) to Heavy Fuel Oil no. 6 and styrene by using a battery of molecular, cell and tissue level biomarkers. Turbots were exposed to styrene for 7 days and to the diluted soluble fraction of the Oil (10%) for 14 days, and then allowed to recover in clean seawater for the same time periods. cyp1a1 transcript was overexpressed in turbots after 3 and 14 days of exposure to Heavy Fuel Oil, whereas ahr transcription was not modulated after Heavy Fuel Oil and styrene exposure. pparα transcription level was significantly up-regulated after 3 days of treatment with styrene. Liver activity of peroxisomal acyl-CoA oxidase (AOX) was significantly induced after 14 days of Oil exposure, but it was not affected by styrene. Hepatocyte lysosomal membrane stability (LMS) was significantly reduced after exposure to both treatments, indicating that the tested compounds significantly impaired fish health. Both AOX and LMS values returned to control levels after the recovery period. No differences in gamete development were observed between Fuel- or styrene- exposed fish and control fish, and vitellogenin plasma levels were low, suggesting no xenoestrogenic effects of Fuel Oil or styrene. While styrene did not cause any increase in the prevalence of liver histopathological alterations, prevalence of extensive cell vacuolization increased after exposure to Heavy Fuel Oil for 14 days. In conclusion, the suite of selected biomarkers proved to be useful to determine the early impact of and recovery from exposure to tested compounds in turbot.
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Transcriptional responses of cancer-related genes in turbot Scophthalmus maximus and mussels Mytilus edulis exposed to Heavy Fuel Oil no. 6 and styrene
Ecotoxicology, 2012Co-Authors: Pamela Ruiz, Amaia Orbea, Jeanette M. Rotchell, Miren P. CajaravilleAbstract:Recent spills in European waters have released polycyclic aromatic hydrocarbons, important components of Heavy Fuel Oil, and the hydrocarbon styrene. Heavy Fuel Oil and styrene are classified as potentially genotoxic and carcinogenic. Here we investigate transcription of genes involved in cancer development in the liver of juvenile turbots and in the digestive gland of mussels exposed to Heavy Fuel Oil and to styrene and after a recovery period. In turbot, Oil produced a significant up-regulation of p53 and gadd45α after 14 days exposure. cyclin G1 was up-regulated after 7 days treatment with styrene. In mussels, ras was down-regulated in both treatments after the recovery periods. No mutations in ras hotspots were detected in exposed mussels. gadd45α was up-regulated after the recovery period of the styrene experiment. Overall, transcriptional responses differed in mussels compared to turbot. Turbot responded to hydrocarbon exposure by triggering cell cycle arrest ( p53 ) and DNA repair ( gadd45α ).
Rene Ocampobarrera - One of the best experts on this subject based on the ideXlab platform.
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an experimental study of the effect of water content on combustion of Heavy Fuel Oil water emulsion droplets
Combustion and Flame, 2001Co-Authors: Rene Ocampobarrera, Rafael Villasenor, Antonio DiegomarinAbstract:Experiments of isolated high asphaltene droplets of Heavy Fuel Oil/water emulsion were performed to investigate the non-steady behavior of the burning droplets. High-resolution video methods allowed monitoring of the various combustion stages. A highly radiant (1000 °C/s) oxidizing environment was necessary to enhance the volatility differential of the high asphaltene Fuel, thus reducing uncertainties because of the presence of the fiber. Data on size and temperature histories were obtained and coke residues were analyzed by a Scanning Electron Microscope. A lower and upper bound for ignition time delay was established. The error defined as the time lag between these two limits never exceeded 10 ms, which is the maximum time for soot to form in the flame after actual ignition. The ignition time delay of emulsions was longer than for an ordinary Heavy Fuel Oil (HFO) droplets of the same size. The peak temperature of emulsions occurred much earlier in time. The steeper temperature rise seen in the emulsions for portions of their combustion history is evidence of both soot reduction and the extent of burnout of the cenospheres, which is an important aspect in the reduction of pollutant emissions. The occurrence of swelling, disruptive bOiling, splashing and the formation of coke were clearly identified by three characteristic combustion times. The emulsion droplets showed swellings of considerable magnitude relative to that of HFO. Coking of the solid phase took place by a dramatic eruption during the last moments of the droplet lifetime when the molecular structure of the cenosphere appeared to be molded. Coke particles formed from emulsions were more void with thinner and fragile shells suggesting that an amorphous-like molecular structure could have developed as opposed to the more compact shell structure observed for HFO residues, which were harder and more reticent to burning. Excess burnout time or the ratio of burnout time of the emulsions was dependent on the water concentration, indicating that less oxidation time was required for coke particles from emulsions than from Heavy Fuel Oil.