The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Brad R. Murray - One of the best experts on this subject based on the ideXlab platform.
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Relationships among leaf flammability attributes and identifying low-leaf-flammability species at the wildland–urban interface
International Journal of Wildland Fire, 2019Co-Authors: Dw Krix, Megan L. Phillips, Brad R. MurrayAbstract:Leaf flammability is a multidimensional plant functional trait with emerging importance for wildfire risk management. Understanding relationships among leaf flammability attributes not only provides information about the properties of leaves as fuels in the wildland–urban interface (WUI), it can also offer an effective way to identify low-leaf-flammability species. We examined relationships between leaf ignitibility, sustainability and combustibility among 60 plant species of the WUI of eastern Australia. We found that leaf ignitibility and sustainability worked in opposition to each other as dimensions of flammability. Species with leaves that were slow to ignite were those with leaves that sustained burning for the longest, whereas species with leaves that were fast to ignite had leaves that burned for the shortest periods of time. Low leaf combustibility was related to short leaf burning sustainability but not to ignitibility. We created an overall leaf flammability index (OLFI) to rank species on emergent properties of ignitibility, sustainability and combustibility attributes in combination. We found that low-leaf-flammability species with low OLFI values had small leaf area, high leaf mass per area and high leaf water content. Our findings have implications for species selection for green firebreaks in the WUI.
Per Johan Brandvik - One of the best experts on this subject based on the ideXlab platform.
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comparing Ignitability for in situ burning of oil spills for an asphaltenic a waxy and a light crude oil as a function of weathering conditions under arctic conditions
Cold Regions Science and Technology, 2012Co-Authors: Janne Frittrasmussen, Per Johan Brandvik, Arne Villumsen, Erling Halfdan StenbyAbstract:Abstract In situ burning of oil spills in the Arctic is a promising countermeasure. In spite of the research already conducted more knowledge is needed especially regarding burning of weathered oils. This paper uses a new laboratory burning cell (100 mL sample) to test three Norwegian crude oils, Grane (asphalthenic), Kobbe (light oil) and Norne (waxy), for Ignitability as a function of ice conditions and weathering degree. The crude oils (9 L) were weathered in a laboratory basin (4.8 m3) under simulated arctic conditions (0, 50 and 90% ice cover). The laboratory burning tests show that the Ignitability is dependent on oil composition, ice conditions and weathering degree. In open water, oil spills rapidly become “not ignitable” due to the weathering e.g. high water content and low content of residual volatile components. The slower weathering of oil spills in ice (50 and 90% ice cover) results in longer time-windows for the oil to be ignitable. The composition of the oils is important for the window of opportunity. The asphalthenic Grane crude oil had a limited time-window for in situ burning (9 h or less), while the light Kobbe crude oil and the waxy Norne crude oil had the longest time-windows for in situ burning (from 18 h to more than 72 h). Such information regarding time windows for using in situ burning is very important for both contingency planning and operational use of in situ burning.
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measuring Ignitability for in situ burning of oil spills weathered under arctic conditions from laboratory studies to large scale field experiments
Marine Pollution Bulletin, 2011Co-Authors: Janne Frittrasmussen, Per Johan BrandvikAbstract:This paper compares the Ignitability of Troll B crude oil weathered under simulated Arctic conditions (0%, 50% and 90% ice cover). The experiments were performed in different scales at SINTEF's laboratories in Trondheim, field research station on Svalbard and in broken ice (70-90% ice cover) in the Barents Sea. Samples from the weathering experiments were tested for Ignitability using the same laboratory burning cell. The measured Ignitability from the experiments in these different scales showed a good agreement for samples with similar weathering. The ice conditions clearly affected the weathering process, and 70% ice or more reduces the weathering and allows a longer time window for in situ burning. The results from the Barents Sea revealed that weathering and Ignitability can vary within an oil slick. This field use of the burning cell demonstrated that it can be used as an operational tool to monitor the Ignitability of oil spills.
Makoto Kohga - One of the best experts on this subject based on the ideXlab platform.
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influence of iron oxide on thermal decomposition behavior and burning characteristics of ammonium nitrate ammonium perchlorate based composite propellants
Combustion and Flame, 2018Co-Authors: Makoto Kohga, Shimpei TogoAbstract:Abstract The thermal decomposition behavior and burning characteristics of ammonium nitrate(AN)/ammonium perchlorate(AP) propellants supplemented with Fe2O3 were investigated. Based on these data, the performance differences between the propellants with Fe2O3 and those without Fe2O3 were investigated to reveal the influence of Fe2O3 on the thermal decomposition behavior and burning characteristics of AN/AP-based composite propellants. TG-DTA showed the peak temperature and temperature range of thermal decomposition due to AN decomposition to be independent of the presence of Fe2O3. The peak and the offset temperature of thermal decomposition due to AP decomposition decreased owing to the addition of Fe2O3, while the onset temperature did not vary. The burning rate of the AN/AP propellant was increased by the addition of Fe2O3; the effect of Fe2O3 on increasing the burning rate was influenced by the type of oxidizer, AP content in the oxidizer (ξ), and AP size. Furthermore, Fe2O3 allowed the suppression of the remarkable heterogeneity of the combustion wave of the AN/AP propellant without Fe2O3. The Ignitability of the AN/AP propellant was improved by the addition of Fe2O3, except for the propellant with a ξ of 0.4. The cause of depressed Ignitability by the addition of Fe2O3 for the propellant with a ξ of 0.4 is discussed based on thermogravimetry-differential thermal analysis, the visual observations of the unignited propellant surfaces, and the decomposition phenomena of the propellants using a high-temperature observation equipment. A large quantity of AN remained on the surface of the unignited propellant at 0.5 MPa. The cause of the depressed Ignitability is that AN, AP, and HTPB do not simultaneously decompose and as a result AN remains on the burning surface. Thus, the burning surface of AN did not regress simultaneously with the burning surface of the AP-filled region, the matrix of AP, and HTPB.
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burning characteristics of ammonium nitrate based composite propellants supplemented with mno2
Propellants Explosives Pyrotechnics, 2013Co-Authors: Tomoki Naya, Makoto KohgaAbstract:Ammonium nitrate (AN)-based composite propellants have several major problems, namely, a low burning rate, poor Ignitability, low energy, and high hygroscopicity. The addition of a burning catalyst proved to be effective in improving the burning characteristics of AN-based propellants. In this study, the burning characteristics of AN-based propellants supplemented with MnO2 as a burning catalyst were investigated. The addition of MnO2 is known to improve the Ignitability at low pressure. The most effective amount of MnO2 added (ξ) for increasing the burning rate is found to be 4 %. The increasing ratio with ξ is virtually independent of the burning pressure and the AN content. However, the pressure exponent unfortunately increased by addition of MnO2. The apparent activation energy of the thermal decomposition for AN and the propellant is decreased by addition of MnO2. From thermal decomposition kinetics it was found that MnO2 could accelerate the thermal decomposition reaction of AN in the condensed phase, and therefore, the burning characteristics of the AN-based propellant are improved.
Dw Krix - One of the best experts on this subject based on the ideXlab platform.
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Relationships among leaf flammability attributes and identifying low-leaf-flammability species at the wildland-urban interface
'CSIRO Publishing', 2019Co-Authors: Dw Krix, Ml Phillips, Br MurrayAbstract:© 2019 IAWF. Leaf flammability is a multidimensional plant functional trait with emerging importance for wildfire risk management. Understanding relationships among leaf flammability attributes not only provides information about the properties of leaves as fuels in the wildland-urban interface (WUI), it can also offer an effective way to identify low-leaf-flammability species. We examined relationships between leaf ignitibility, sustainability and combustibility among 60 plant species of the WUI of eastern Australia. We found that leaf ignitibility and sustainability worked in opposition to each other as dimensions of flammability. Species with leaves that were slow to ignite were those with leaves that sustained burning for the longest, whereas species with leaves that were fast to ignite had leaves that burned for the shortest periods of time. Low leaf combustibility was related to short leaf burning sustainability but not to ignitibility. We created an overall leaf flammability index (OLFI) to rank species on emergent properties of ignitibility, sustainability and combustibility attributes in combination. We found that low-leaf-flammability species with low OLFI values had small leaf area, high leaf mass per area and high leaf water content. Our findings have implications for species selection for green firebreaks in the WUI
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Relationships among leaf flammability attributes and identifying low-leaf-flammability species at the wildland–urban interface
International Journal of Wildland Fire, 2019Co-Authors: Dw Krix, Megan L. Phillips, Brad R. MurrayAbstract:Leaf flammability is a multidimensional plant functional trait with emerging importance for wildfire risk management. Understanding relationships among leaf flammability attributes not only provides information about the properties of leaves as fuels in the wildland–urban interface (WUI), it can also offer an effective way to identify low-leaf-flammability species. We examined relationships between leaf ignitibility, sustainability and combustibility among 60 plant species of the WUI of eastern Australia. We found that leaf ignitibility and sustainability worked in opposition to each other as dimensions of flammability. Species with leaves that were slow to ignite were those with leaves that sustained burning for the longest, whereas species with leaves that were fast to ignite had leaves that burned for the shortest periods of time. Low leaf combustibility was related to short leaf burning sustainability but not to ignitibility. We created an overall leaf flammability index (OLFI) to rank species on emergent properties of ignitibility, sustainability and combustibility attributes in combination. We found that low-leaf-flammability species with low OLFI values had small leaf area, high leaf mass per area and high leaf water content. Our findings have implications for species selection for green firebreaks in the WUI.
Janne Frittrasmussen - One of the best experts on this subject based on the ideXlab platform.
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comparing Ignitability for in situ burning of oil spills for an asphaltenic a waxy and a light crude oil as a function of weathering conditions under arctic conditions
Cold Regions Science and Technology, 2012Co-Authors: Janne Frittrasmussen, Per Johan Brandvik, Arne Villumsen, Erling Halfdan StenbyAbstract:Abstract In situ burning of oil spills in the Arctic is a promising countermeasure. In spite of the research already conducted more knowledge is needed especially regarding burning of weathered oils. This paper uses a new laboratory burning cell (100 mL sample) to test three Norwegian crude oils, Grane (asphalthenic), Kobbe (light oil) and Norne (waxy), for Ignitability as a function of ice conditions and weathering degree. The crude oils (9 L) were weathered in a laboratory basin (4.8 m3) under simulated arctic conditions (0, 50 and 90% ice cover). The laboratory burning tests show that the Ignitability is dependent on oil composition, ice conditions and weathering degree. In open water, oil spills rapidly become “not ignitable” due to the weathering e.g. high water content and low content of residual volatile components. The slower weathering of oil spills in ice (50 and 90% ice cover) results in longer time-windows for the oil to be ignitable. The composition of the oils is important for the window of opportunity. The asphalthenic Grane crude oil had a limited time-window for in situ burning (9 h or less), while the light Kobbe crude oil and the waxy Norne crude oil had the longest time-windows for in situ burning (from 18 h to more than 72 h). Such information regarding time windows for using in situ burning is very important for both contingency planning and operational use of in situ burning.
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measuring Ignitability for in situ burning of oil spills weathered under arctic conditions from laboratory studies to large scale field experiments
Marine Pollution Bulletin, 2011Co-Authors: Janne Frittrasmussen, Per Johan BrandvikAbstract:This paper compares the Ignitability of Troll B crude oil weathered under simulated Arctic conditions (0%, 50% and 90% ice cover). The experiments were performed in different scales at SINTEF's laboratories in Trondheim, field research station on Svalbard and in broken ice (70-90% ice cover) in the Barents Sea. Samples from the weathering experiments were tested for Ignitability using the same laboratory burning cell. The measured Ignitability from the experiments in these different scales showed a good agreement for samples with similar weathering. The ice conditions clearly affected the weathering process, and 70% ice or more reduces the weathering and allows a longer time window for in situ burning. The results from the Barents Sea revealed that weathering and Ignitability can vary within an oil slick. This field use of the burning cell demonstrated that it can be used as an operational tool to monitor the Ignitability of oil spills.
