Fast and Luminous Transients from the Explosions of Long-lived Massive White Dwarf Merger Remnants

NASA Astrophysics Data System (ADS)

Brooks, Jared; Schwab, Josiah; Bildsten, Lars; Quataert, Eliot; Paxton, Bill; Blinnikov, Sergei; Sorokina, Elena

2017-12-01

We study the evolution and final outcome of long-lived (≈ {10}5 years) remnants from the merger of an He white dwarf (WD) with a more massive C/O or O/Ne WD. Using Modules for Experiments in Stellar Astrophysics ({\\mathtt{MESA}}), we show that these remnants have a red giant configuration supported by steady helium burning, adding mass to the WD core until it reaches {M}{core}≈ 1.12{--}1.20 {M}⊙ . At that point, the base of the surface convection zone extends into the burning layer, mixing the helium-burning products (primarily carbon and magnesium) throughout the convective envelope. Further evolution depletes the convective envelope of helium and dramatically slows the mass increase of the underlying WD core. The WD core mass growth re-initiates after helium depletion, as then an uncoupled carbon-burning shell is ignited and proceeds to burn the fuel from the remaining metal-rich extended envelope. For large enough initial total merger masses, O/Ne WD cores would experience electron-capture triggered collapse to neutron stars (NSs) after growing to near Chandrasekhar mass ({M}{Ch}). Massive C/O WD cores could suffer the same fate after a carbon-burning flame converts them to ONe. The NS formation would release ≈ {10}50 erg into the remaining extended low mass envelope. Using the STELLA radiative transfer code, we predict the resulting optical light curves from these exploded envelopes. Reaching absolute magnitudes of {M}V≈ -17, these transients are bright for about one week and have many features of the class of luminous, rapidly evolving transients studied by Drout and collaborators.

The s-process in massive stars: the Shell C-burning contribution

NASA Astrophysics Data System (ADS)

Pignatari, Marco; Gallino, R.; Baldovin, C.; Wiescher, M.; Herwig, F.; Heger, A.; Heil, M.; Käppeler, F.

In massive stars the s¡ process (slow neutron capture process) is activated at different tempera- tures, during He¡ burning and during convective shell C¡ burning. At solar metallicity, the neu- tron capture process in the convective C¡ shell adds a substantial contribution to the s¡ process yields made by the previous core He¡ burning, and the final results carry the signature of both processes. With decreasing metallicity, the contribution of the C¡ burning shell to the weak s¡ process rapidly decreases, because of the effect of the primary neutron poisons. On the other hand, also the s¡ process efficiency in the He core decreases with metallicity.

The Last Minutes of Oxygen Shell Burning in a Massive Star

NASA Astrophysics Data System (ADS)

Müller, Bernhard; Viallet, Maxime; Heger, Alexander; Janka, Hans-Thomas

2016-12-01

We present the first 4π-three-dimensional (3D) simulation of the last minutes of oxygen shell burning in an 18 M ⊙ supernova progenitor up to the onset of core collapse. A moving inner boundary is used to accurately model the contraction of the silicon and iron core according to a one-dimensional stellar evolution model with a self-consistent treatment of core deleptonization and nuclear quasi-equilibrium. The simulation covers the full solid angle to allow the emergence of large-scale convective modes. Due to core contraction and the concomitant acceleration of nuclear burning, the convective Mach number increases to ˜0.1 at collapse, and an ℓ = 2 mode emerges shortly before the end of the simulation. Aside from a growth of the oxygen shell from 0.51 M ⊙ to 0.56 M ⊙ due to entrainment from the carbon shell, the convective flow is reasonably well described by mixing-length theory, and the dominant scales are compatible with estimates from linear stability analysis. We deduce that artificial changes in the physics, such as accelerated core contraction, can have precarious consequences for the state of convection at collapse. We argue that scaling laws for the convective velocities and eddy sizes furnish good estimates for the state of shell convection at collapse and develop a simple analytic theory for the impact of convective seed perturbations on shock revival in the ensuing supernova. We predict a reduction of the critical luminosity for explosion by 12%-24% due to seed asphericities for our 3D progenitor model relative to the case without large seed perturbations.

The Interior Angular Momentum of Core Hydrogen Burning Stars from Gravity-mode Oscillations

NASA Astrophysics Data System (ADS)

Aerts, C.; Van Reeth, T.; Tkachenko, A.

2017-09-01

A major uncertainty in the theory of stellar evolution is the angular momentum distribution inside stars and its change during stellar life. We compose a sample of 67 stars in the core hydrogen burning phase with a {log} g value from high-resolution spectroscopy, as well as an asteroseismic estimate of the near-core rotation rate derived from gravity-mode oscillations detected in space photometry. This assembly includes 8 B-type stars and 59 AF-type stars, covering a mass range from 1.4 to 5 M ⊙, I.e., it concerns intermediate-mass stars born with a well-developed convective core. The sample covers projected surface rotation velocities v\\sin I\\in [9,242] km s-1 and core rotation rates up to 26 μHz, which corresponds to 50% of the critical rotation frequency. We find deviations from rigid rotation to be moderate in the single stars of this sample. We place the near-core rotation rates in an evolutionary context and find that the core rotation must drop drastically before or during the short phase between the end of the core hydrogen burning and the onset of core helium burning. We compute the spin parameter, which is the ratio of twice the rotation rate to the mode frequency (also known as the inverse Rossby number), for 1682 gravity modes and find the majority (95%) to occur in the sub-inertial regime. The 10 stars with Rossby modes have spin parameters between 14 and 30, while the gravito-inertial modes cover the range from 1 to 15.

Eurasian methoxy aromatic acid ice core record of biomass burning

NASA Astrophysics Data System (ADS)

Grieman, M. M.; Aydin, M.; Fritzsche, D.; McConnell, J. R.; Opel, T.; Sigl, M.; Saltzman, E. S.

2017-12-01

On a global basis, wildfires affect the carbon cycle, atmospheric chemistry, climate, and ecosystem dynamics. Well-dated regional proxy records can provide insight into the relationship between biomass burning and climate on millennial and centennial timescales. There is little historical information about long-term regional biomass burning variability in Siberia, the largest forested area in the Northern Hemisphere. In this study, vanillic acid and para-hydroxybenzoic acid were analyzed in the Eurasian Arctic Akademii Nauk ice core in samples covering the past 2600 years. These aromatic acids are generated during burning from the pyrolysis of lignin and transported as atmospheric aerosol. This is the first millennial-scale ice core record of these aromatic acids. Ice core meltwater samples were analyzed for vanillic acid and para-hydroxybenzoic acid using ion chromatography and electrospray tandem mass spectrometric detection. The levels of vanillic acid and para-hydroxybenzoic acid ranged from <0.05 to about 1 ppb. Three periods of strongly elevated levels were found during the preindustrial late Holocene: 650-300 BCE, 340-660 CE, and 1460-1660 CE. The most recent of these periods coincides with increased pulsing of ice-rafted debris in the North Atlantic (or Bond event) and a weakened Asian monsoon suggesting a link between Siberian burning and global patterns of climate change on centennial timescales.

The evolution of massive stars and their spectra. I. A non-rotating 60 M⊙ star from the zero-age main sequence to the pre-supernova stage

NASA Astrophysics Data System (ADS)

Groh, Jose H.; Meynet, Georges; Ekström, Sylvia; Georgy, Cyril

2014-04-01

For the first time, the interior and spectroscopic evolution of a massive star is analyzed from the zero-age main sequence (ZAMS) to the pre-supernova (SN) stage. For this purpose, we combined stellar evolution models using the Geneva code and stellar atmospheric/wind models using CMFGEN. With our approach, we were able to produce observables, such as a synthetic high-resolution spectrum and photometry, thereby aiding the comparison between evolution models and observed data. Here we analyze the evolution of a non-rotating 60 M⊙ star and its spectrum throughout its lifetime. Interestingly, the star has a supergiant appearance (luminosity class I) even at the ZAMS. We find the following evolutionary sequence of spectral types: O3 I (at the ZAMS), O4 I (middle of the H-core burning phase), B supergiant (BSG), B hypergiant (BHG), hot luminous blue variable (LBV; end of H-core burning), cool LBV (H-shell burning through the beginning of the He-core burning phase), rapid evolution through late WN and early WN, early WC (middle of He-core burning), and WO (end of He-core burning until core collapse). We find the following spectroscopic phase lifetimes: 3.22 × 106 yr for the O-type, 0.34 × 105 yr (BSG), 0.79 × 105 yr (BHG), 2.35 × 105 yr (LBV), 1.05 × 105 yr (WN), 2.57 × 105 yr (WC), and 3.80 × 104 yr (WO). Compared to previous studies, we find a much longer (shorter) duration for the early WN (late WN) phase, as well as a long-lived LBV phase. We show that LBVs arise naturally in single-star evolution models at the end of the MS when the mass-loss rate increases as a consequence of crossing the bistability limit. We discuss the evolution of the spectra, magnitudes, colors, and ionizing flux across the star's lifetime, and the way they are related to the evolution of the interior. We find that the absolute magnitude of the star typically changes by ~6 mag in optical filters across the evolution, with the star becoming significantly fainter in optical filters at the end of the evolution, when it becomes a WO just a few 104 years before the SN explosion. We also discuss the origin of the different spectroscopic phases (i.e., O-type, LBV, WR) and how they are related to evolutionary phases (H-core burning, H-shell burning, He-core burning). Tables 1, 4 and 5 are available in electronic form at http://www.aanda.orgSynthetic spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/A30

What could have caused pre-industrial biomass burning emissions to exceed current rates?

NASA Astrophysics Data System (ADS)

van der Werf, G. R.; Peters, W.; van Leeuwen, T. T.; Giglio, L.

2013-01-01

Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary landscape fire emissions and the TM5 chemical transport model driven by present-day atmospheric transport and OH concentrations, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various landscape biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g., fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data, all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture exceeding current levels, despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation; satellite data indicates that the majority of savannas have not burned in the past 10 yr, even in Africa, which is considered "the burning continent". Although we have not considered increased charcoal burning or changes in OH concentrations as potential causes for the elevated CO concentrations found at SPO, it is unlikely they can explain the large increase found in the CO concentrations in ice core data. Confirmation of the CO ice core data would therefore call for radical new thinking about causes of variable global fire rates over recent centuries.

THE LAST MINUTES OF OXYGEN SHELL BURNING IN A MASSIVE STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Müller, Bernhard; Viallet, Maxime; Janka, Hans-Thomas

We present the first  4 π– three-dimensional (3D) simulation of the last minutes of oxygen shell burning in an 18 M {sub ⊙} supernova progenitor up to the onset of core collapse. A moving inner boundary is used to accurately model the contraction of the silicon and iron core according to a one-dimensional stellar evolution model with a self-consistent treatment of core deleptonization and nuclear quasi-equilibrium. The simulation covers the full solid angle to allow the emergence of large-scale convective modes. Due to core contraction and the concomitant acceleration of nuclear burning, the convective Mach number increases to ∼0.1 at collapse,more » and an ℓ  = 2 mode emerges shortly before the end of the simulation. Aside from a growth of the oxygen shell from 0.51 M {sub ⊙} to 0.56 M {sub ⊙} due to entrainment from the carbon shell, the convective flow is reasonably well described by mixing-length theory, and the dominant scales are compatible with estimates from linear stability analysis. We deduce that artificial changes in the physics, such as accelerated core contraction, can have precarious consequences for the state of convection at collapse. We argue that scaling laws for the convective velocities and eddy sizes furnish good estimates for the state of shell convection at collapse and develop a simple analytic theory for the impact of convective seed perturbations on shock revival in the ensuing supernova. We predict a reduction of the critical luminosity for explosion by 12% – 24% due to seed asphericities for our 3D progenitor model relative to the case without large seed perturbations.« less

The study of capability natural uranium as fuel cycle input for long life gas cooled fast reactors with helium as coolant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ariani, Menik, E-mail: menikariani@gmail.com; Satya, Octavianus Cakra; Monado, Fiber

The objective of the present research is to assess the feasibility design of small long-life Gas Cooled Fast Reactor with helium as coolant. GCFR included in the Generation-IV reactor systems are being developed to provide sustainable energy resources that meet future energy demand in a reliable, safe, and proliferation-resistant manner. This reactor can be operated without enrichment and reprocessing forever, once it starts. To obtain the capability of consuming natural uranium as fuel cycle input modified CANDLE burn-up scheme was adopted in this system with different core design. This study has compared the core with three designs of core reactorsmore » with the same thermal power 600 MWth. The fuel composition each design was arranged by divided core into several parts of equal volume axially i.e. 6, 8 and 10 parts related to material burn-up history. The fresh natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of the region (i) into region (i+1) region after the end of 10 years burn-up cycle. The calculation results shows that for the burn-up strategy on “Region-8” and “Region-10” core designs, after the reactors start-up the operation furthermore they only needs natural uranium supply to the next life operation until one period of refueling (10 years).« less

No nitrate spikes detectable in several polar ice cores following the largest known solar events

NASA Astrophysics Data System (ADS)

Mekhaldi, Florian; McConnell, Joseph R.; Adolphi, Florian; Arienzo, Monica; Chellman, Nathan J.; Maselli, Olivia; Sigl, Michael; Muscheler, Raimund

2017-04-01

Solar energetic particle (SEP) events are a genuine and recognized threat to our modern society which is increasingly relying on satellites and technological infrastructures. However, knowledge on the frequency and on the upper limit of the intensity of major solar storms is largely limited by the relatively short direct observation period. In an effort to extend the observation period and because atmospheric ionization induced by solar particles can lead to the production of odd nitrogen, spikes in the nitrate content of ice cores have been tentatively used to reconstruct both the occurrence and intensity of past SEP events. Yet the reliability of its use as such a proxy has been long debated. This is partly due to differing chemistry-climate model outputs, equivocal detection of nitrate spikes in single ice cores for single events, and possible alternative sources to explain nitrate spikes in ice cores. Here we present nitrate measurements from several Antarctic and Greenland ice cores for time periods covering the largest known solar events. More specifically, we use new highly-resolved nitrate and biomass burning proxy species data (e.g. black carbon) from continuous flow analysis following the largest known solar events from the paleo record - the SEP events of 775 and 994 AD. We also consider the historical Carrington event of 1859 as well as contemporary events from the past 60 years which were observed by satellites. Doing so we show that i) there are no reproducible nitrate spikes in Greenland and Antarctic ice cores following any of these major events and that ii) most nitrate spikes found in ice cores are related to biomass burning plumes. Our analysis thus suggests that ice-core nitrate data is not a reliable proxy for atmospheric ionization by SEP events. In light of our results, we advocate that nitrate spikes so far identified from single ice cores should not be used to assess the intensity and occurrence rate of extreme solar events.

An Improved Extraction and Analysis Technique for Determination of Carbon Monoxide Stable Isotopes and Mixing Ratios from Ice Core and Atmospheric Air Samples.

NASA Astrophysics Data System (ADS)

Place, P., Jr.; Petrenko, V. V.; Vimont, I.

2017-12-01

Carbon Monoxide (CO) is an important atmospheric trace gas that affects the oxidative capacity of the atmosphere and contributes indirectly to anthropogenic radiative forcing. Carbon monoxide stable isotopes can also serve as a tracer for variations in biomass burning, particularly in the preindustrial atmosphere. A good understanding of the past variations in CO mole fractions and isotopic composition can help improve the skill of chemical transport models and constrain biomass burning changes. Ice cores may preserve a record of past atmospheric CO for analysis and interpretation. To this end, a new extraction system has been developed for analysis of stable isotopes (δ13CO and δC18O) of atmospheric carbon monoxide from ice core and atmospheric air samples. This system has been designed to measure relatively small sample sizes (80 cc STP of air) to accommodate the limited availability of ice core samples. Trapped air is extracted from ice core samples via melting in a glass vacuum chamber. This air is expanded into a glass expansion loop and then compressed into the sample loop of a Reducing Gas Detector (Peak Laboratories, Peak Performer 1 RCP) for the CO mole fraction measurement. The remaining sample gas will be expelled from the melt vessel into a larger expansion loop via headspace compression for isotopic analysis. The headspace compression will be accomplished by introduction of clean degassed water into the bottom of the melt vessel. Isotopic analysis of the sample gas is done utilizing the Schütze Reagent to convert the carbon monoxide to carbon dioxide (CO2) which is then measured using continuous-flow isotope ratio mass spectrometry (Elementar Americas, IsoPrime 100). A series of cryogenic traps are used to purify the sample air, capture the converted sample CO2, and cryofocus the sample CO2 prior to injection.

ANALYSIS OF LEAD IN CANDLE PARTICULATE EMISSIONS BY XRF USING UNIQUANT 4

EPA Science Inventory

As part of an extensive program to study the small combustion sources of indoor fine particulate matter (PM), candles with lead-core wicks were burned in a 46-L glass flow- through chamber. The particulate emissions with aerodynamic diameters <10 micrometers (PM10) were captured ...

Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars.

PubMed

Bedding, Timothy R; Mosser, Benoit; Huber, Daniel; Montalbán, Josefina; Beck, Paul; Christensen-Dalsgaard, Jørgen; Elsworth, Yvonne P; García, Rafael A; Miglio, Andrea; Stello, Dennis; White, Timothy R; De Ridder, Joris; Hekker, Saskia; Aerts, Conny; Barban, Caroline; Belkacem, Kevin; Broomhall, Anne-Marie; Brown, Timothy M; Buzasi, Derek L; Carrier, Fabien; Chaplin, William J; Di Mauro, Maria Pia; Dupret, Marc-Antoine; Frandsen, Søren; Gilliland, Ronald L; Goupil, Marie-Jo; Jenkins, Jon M; Kallinger, Thomas; Kawaler, Steven; Kjeldsen, Hans; Mathur, Savita; Noels, Arlette; Aguirre, Victor Silva; Ventura, Paolo

2011-03-31

Red giants are evolved stars that have exhausted the supply of hydrogen in their cores and instead burn hydrogen in a surrounding shell. Once a red giant is sufficiently evolved, the helium in the core also undergoes fusion. Outstanding issues in our understanding of red giants include uncertainties in the amount of mass lost at the surface before helium ignition and the amount of internal mixing from rotation and other processes. Progress is hampered by our inability to distinguish between red giants burning helium in the core and those still only burning hydrogen in a shell. Asteroseismology offers a way forward, being a powerful tool for probing the internal structures of stars using their natural oscillation frequencies. Here we report observations of gravity-mode period spacings in red giants that permit a distinction between evolutionary stages to be made. We use high-precision photometry obtained by the Kepler spacecraft over more than a year to measure oscillations in several hundred red giants. We find many stars whose dipole modes show sequences with approximately regular period spacings. These stars fall into two clear groups, allowing us to distinguish unambiguously between hydrogen-shell-burning stars (period spacing mostly ∼ 50 seconds) and those that are also burning helium (period spacing ∼ 100 to 300 seconds).

Temperature responses in severely burned children during exercise in a hot environment.

PubMed

McEntire, Serina J; Chinkes, David L; Herndon, David N; Suman, Oscar E

2010-01-01

The authors have previously described thermoregulatory responses of severely burned children during submaximal exercise in a thermoneutral environment. However, the thermoregulatory response of burned children to exercise in the heat is not well understood and could have important safety implications for rehabilitation. Children (n = 10) with >40% TBSA burns and nonburned children (n = 10) performed a 30-minute bout of treadmill exercise at 75% of their peak aerobic power in a heated environment. Intestinal temperature, burned and unburned skin temperature, and heart rate were recorded pre-exercise, every 2 minutes during exercise, and during recovery. Three of the 10 burned children completed the exercise bout in the heat; however, all the nonburned children completed the 30-minute bout. One burned child reached a core body temperature >39 degrees C at minute 23. Burned children had significantly higher core body temperature through the first 12 minutes of exercise compared with nonburned children. However, nine of 10 (90%) burned children did not become hyperthermic during exercise in the heat. Specific to this study, hyperthermia did not typically occur in burned children, relative to nonburned children. Whether this is due to an intolerance to exercise in the heat or to an inability to generate sufficient heat during exercise needs to be explored further.

Preliminary safety analysis of Pb-Bi cooled 800 MWt modified CANDLE burn-up scheme based fast reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su'ud, Zaki, E-mail: szaki@fi.itba.c.id; Sekimoto, H., E-mail: hsekimot@gmail.com

2014-09-30

Pb-Bi Cooled fast reactors with modified CANDLE burn-up scheme with 10 regions and 10 years cycle length has been investigated from neutronic aspects. In this study the safety aspect of such reactors have been investigated and discussed. Several condition of unprotected loss of flow (ULOF) and unprotected rod run-out transient over power (UTOP) have been simulated and the results show that the reactors excellent safety performance. At 80 seconds after unprotected loss of flow condition, the core flow rate drop to about 25% of its initial flow and slowly move toward its natural circulation level. The maximum fuel temperature canmore » be managed below 1000°C and the maximum cladding temperature can be managed below 700°C. The dominant reactivity feedback is radial core expansion and Doppler effect, followed by coolant density effect and fuel axial expansion effect.« less

Historic records of organic compounds from a high Alpine glacier: influences of biomass burning, anthropogenic emissions, and dust transport

NASA Astrophysics Data System (ADS)

Müller-Tautges, C.; Eichler, A.; Schwikowski, M.; Pezzatti, G. B.; Conedera, M.; Hoffmann, T.

2016-01-01

Historic records of α-dicarbonyls (glyoxal, methylglyoxal), carboxylic acids (C6-C12 dicarboxylic acids, pinic acid, p-hydroxybenzoic acid, phthalic acid, 4-methylphthalic acid), and ions (oxalate, formate, calcium) were determined with annual resolution in an ice core from Grenzgletscher in the southern Swiss Alps, covering the time period from 1942 to 1993. Chemical analysis of the organic compounds was conducted using ultra-high-performance liquid chromatography (UHPLC) coupled to electrospray ionization high-resolution mass spectrometry (ESI-HRMS) for dicarbonyls and long-chain carboxylic acids and ion chromatography for short-chain carboxylates. Long-term records of the carboxylic acids and dicarbonyls, as well as their source apportionment, are reported for western Europe. This is the first study comprising long-term trends of dicarbonyls and long-chain dicarboxylic acids (C6-C12) in Alpine precipitation. Source assignment of the organic species present in the ice core was performed using principal component analysis. Our results suggest biomass burning, anthropogenic emissions, and transport of mineral dust to be the main parameters influencing the concentration of organic compounds. Ice core records of several highly correlated compounds (e.g., p-hydroxybenzoic acid, pinic acid, pimelic, and suberic acids) can be related to the forest fire history in southern Switzerland. P-hydroxybenzoic acid was found to be the best organic fire tracer in the study area, revealing the highest correlation with the burned area from fires. Historical records of methylglyoxal, phthalic acid, and dicarboxylic acids adipic acid, sebacic acid, and dodecanedioic acid are comparable with that of anthropogenic emissions of volatile organic compounds (VOCs). The small organic acids, oxalic acid and formic acid, are both highly correlated with calcium, suggesting their records to be affected by changing mineral dust transport to the drilling site.

Measurements of ethane in Antarctic ice cores

NASA Astrophysics Data System (ADS)

Verhulst, K. R.; Fosse, E. K.; Aydin, K. M.; Saltzman, E. S.

2011-12-01

Ethane is one of the most abundant hydrocarbons in the atmosphere. The major ethane sources are fossil fuel production and use, biofuel combustion, and biomass-burning emissions and the primary loss pathway is via reaction with OH. A paleoatmospheric ethane record would be useful as a tracer of biomass-burning emissions, providing a constraint on past changes in atmospheric methane and methane isotopes. An independent biomass-burning tracer would improve our understanding of the relationship between biomass burning and climate. The mean annual atmospheric ethane level at high southern latitudes is about 230 parts per trillion (ppt), and Antarctic firn air measurements suggest that atmospheric ethane levels in the early 20th century were considerably lower (Aydin et al., 2011). In this study, we present preliminary measurements of ethane (C2H6) in Antarctic ice core samples with gas ages ranging from 0-1900 C.E. Samples were obtained from dry-drilled ice cores from South Pole and Vostok in East Antarctica, and from the West Antarctic Ice Sheet Divide (WAIS-D). Gases were extracted from the ice by melting under vacuum in a glass vessel sealed by indium wire and were analyzed using high resolution GC/MS with isotope dilution. Ethane levels measured in ice core samples were in the range 100-220 ppt, with a mean of 157 ± 45 ppt (n=12). System blanks contribute roughly half the amount of ethane extracted from a 300 g ice core sample. These preliminary data exhibit a temporal trend, with higher ethane levels from 0-900 C.E., followed by a decline, reaching a minimum between 1600-1700 C.E. These trends are consistent with variations in ice core methane isotopes and carbon monoxide isotopes (Ferretti et al., 2005, Wang et al., 2010), which indicate changes in biomass burning emissions over this time period. These preliminary data suggest that Antarctic ice core bubbles contain paleoatmospheric ethane levels. With further improvement of laboratory techniques it appears likely that a paleoatmospheric ethane record can be obtained from polar ice cores.

A common explosion mechanism for type Ia supernovae.

PubMed

Mazzali, Paolo A; Röpke, Friedrich K; Benetti, Stefano; Hillebrandt, Wolfgang

2007-02-09

Type Ia supernovae, the thermonuclear explosions of white dwarf stars composed of carbon and oxygen, were instrumental as distance indicators in establishing the acceleration of the universe's expansion. However, the physics of the explosion are debated. Here we report a systematic spectral analysis of a large sample of well-observed type Ia supernovae. Mapping the velocity distribution of the main products of nuclear burning, we constrain theoretical scenarios. We find that all supernovae have low-velocity cores of stable iron-group elements. Outside this core, nickel-56 dominates the supernova ejecta. The outer extent of the iron-group material depends on the amount of nickel-56 and coincides with the inner extent of silicon, the principal product of incomplete burning. The outer extent of the bulk of silicon is similar in all supernovae, having an expansion velocity of approximately 11,000 kilometers per second and corresponding to a mass of slightly over one solar mass. This indicates that all the supernovae considered here burned similar masses and suggests that their progenitors had the same mass. Synthetic light-curve parameters and three-dimensional explosion simulations support this interpretation. A single explosion scenario, possibly a delayed detonation, may thus explain most type Ia supernovae.

Theoretical studies of massive stars. I - Evolution of a 15-solar-mass star from the zero-age main sequence to neon ignition

NASA Technical Reports Server (NTRS)

Endal, A. S.

1975-01-01

The evolution of a star with mass 15 times that of the sun from the zero-age main sequence to neon ignition has been computed by the Henyey method. The hydrogen-rich envelope and all shell sources were explicitly included in the models. An algorithm has been developed for approximating the results of carbon burning, including the branching ratio for the C-12 + C-12 reaction and taking some secondary reactions into account. Penetration of the convective envelope into the core is found to be unimportant during the stages covered by the models. Energy transfer from the carbon-burning shell to the core by degenerate electron conduction becomes important after the core carbon-burning stage. Neon ignition will occur in a semidegenerate core and will lead to a mild 'flash.' Detailed numerical results are given in an appendix. Continuation of the calculations into later stages and variations with the total mass of the star will be discussed in later papers.

DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodenheimer, Peter; D'Angelo, Gennaro; Lissauer, Jack J.

Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M{sub Circled-Plus }, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M{sub Jup}). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M{sub 50}, above which more than 50%more » of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M{sub 50} fall in the range 11.6-13.6 M{sub Jup}, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M{sub 50}. For masses above M{sub 50}, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.« less

Environmentally Responsible Aviation: Propulsion Research to Enable Fuel Burn, Noise and Emissions Reduction

NASA Technical Reports Server (NTRS)

Van Zante, Dale; Suder, Kenneth

2015-01-01

The NASA Environmentally Responsible Aviation (ERA) program is maturing technologies to enable simultaneous reduction of fuel burn, noise and emissions from an aircraft engine system. Three engine related Integrated Technology Demonstrations (ITDs) have been completed at Glenn Research Center in collaboration with Pratt Whitney, General Electric and the Federal Aviation Administration. The engine technologies being matured are: a low NOx, fuel flexible combustor in partnership with Pratt Whitney; an ultra-high bypass, ducted propulsor system in partnership with Pratt Whitney and FAA; and high pressure ratio, front-stage core compressor technology in partnership with General Electric. The technical rationale, test configurations and overall results from the test series in each ITD are described. ERA is using system analysis to project the benefits of the ITD technologies on potential aircraft systems in the 2025 timeframe. Data from the ITD experiments were used to guide the system analysis assumptions. Results from the current assessments for fuel burn, noise and oxides of nitrogen emissions are presented.

Environmentally Responsible Aviation: Propulsion Research to Enable Fuel Burn, Noise and Emissions Reduction

NASA Technical Reports Server (NTRS)

Van Zante, Dale E.; Suder, Kenneth L.

2015-01-01

The NASA Environmentally Responsible Aviation (ERA) program is maturing technologies to enable simultaneous reduction of fuel burn, noise and emissions from an aircraft engine system. Three engine related Integrated Technology Demonstrations (ITDs) have been completed at Glenn Research Center in collaboration with Pratt Whitney, General Electric and the Federal Aviation Administration. The engine technologies being matured are a low NOx, fuel flexible combustor in partnership with Pratt Whitney, an ultra-high bypass, ducted propulsor system in partnership with Pratt Whitney FAA and high pressure ratio, front-stage core compressor technology in partnership with General Electric. The technical rationale, test configurations and overall results from the test series in each ITD are described. ERA is using system analysis to project the benefits of the ITD technologies on potential aircraft systems in the 2025 timeframe. Data from the ITD experiments were used to guide the system analysis assumptions. Results from the current assessments for fuel burn, noise and oxides of nitrogen emissions are presented.

Discovery of the Closest Hot Subdwarf Binary with White Dwarf Companion

NASA Astrophysics Data System (ADS)

Geier, S.; Marsh, T. R.; Dunlap, B. H.; Barlow, B. N.; Schaffenroth, V.; Ziegerer, E.; Heber, U.; Kupfer, T.; Maxted, P. F. L.; Miszalski, B.; Shporer, A.; Telting, J. H.; Ostensen, R. H.; O'Toole, S. J.; Gänsicke, B. T.; Napiwotzki, R.

2013-01-01

We report the discovery of an extremely close, eclipsing binary system. A white dwarf is orbited by a core He-burning compact hot subdwarf star with a period as short as ≃ 0.04987 d making this system the most compact hot subdwarf binary discovered so far. The subdwarf will start to transfer helium-rich material on short timescales of less than 50 Myr. The ignition of He-burning at the surface may trigger carbon-burning in the core although the WD is less massive than the Chandrasekhar limit (> 0.74 M⊙) making this binary a possible progenitor candidate for a supernova type Ia event.

Relative abundance of small mammals in nest core areas and burned wintering areas of Mexican spotted owls in the Sacramento Mountains, New Mexico

Treesearch

Joseph L. Ganey; Sean C. Kyle; Todd A. Rawlinson; Darrell L. Apprill; James P Ward

2014-01-01

Mexican Spotted Owls (Strix occidentalis lucida) are common in older forests within their range but also persist in many areas burned by wildfire and may selectively forage in these areas. One hypothesis explaining this pattern postulates that prey abundance increases in burned areas following wildfire. We observed movement to wintering areas within areas burned by...

What could have caused pre-industrial biomass burning emissions to exceed current rates?

NASA Astrophysics Data System (ADS)

van der Werf, G. R.; Peters, W.; van Leeuwen, T. T.; Giglio, L.

2012-08-01

Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. Here we have analyzed how emissions from several biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary fire emissions and the TM5 chemical transport model, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g. fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture matching current levels despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation; we show that the majority of savannas have not burned in the past 10 yr, even in Africa which is considered "the burning continent". Our new modelling results, together with existing literature, indicate that no definitive conclusions can be drawn about unprecedentedly high or low biomass burning rates from current data analyses.

Key issues review: numerical studies of turbulence in stars

NASA Astrophysics Data System (ADS)

Arnett, W. David; Meakin, Casey

2016-10-01

Three major problems of single-star astrophysics are convection, magnetic fields and rotation. Numerical simulations of convection in stars now have sufficient resolution to be truly turbulent, with effective Reynolds numbers of \\text{Re}>{{10}4} , and some turbulent boundary layers have been resolved. Implications of these developments are discussed for stellar structure, evolution and explosion as supernovae. Methods for three-dimensional (3D) simulations of stars are compared and discussed for 3D atmospheres, solar rotation, core-collapse and stellar boundary layers. Reynolds-averaged Navier-Stokes (RANS) analysis of the numerical simulations has been shown to provide a novel and quantitative estimate of resolution errors. Present treatments of stellar boundaries require revision, even for early burning stages (e.g. for mixing regions during He-burning). As stellar core-collapse is approached, asymmetry and fluctuations grow, rendering spherically symmetric models of progenitors more unrealistic. Numerical resolution of several different types of three-dimensional (3D) stellar simulations are compared; it is suggested that core-collapse simulations may be under-resolved. The Rayleigh-Taylor instability in explosions has a deep connection to convection, for which the abundance structure in supernova remnants may provide evidence.

Global burned-land estimation in Latin America using MODIS composite data.

PubMed

Chuvieco, Emilio; Opazo, Sergio; Sione, Walter; Del Valle, Hector; Anaya, Jesús; Di Bella, Carlos; Cruz, Isabel; Manzo, Lilia; López, Gerardo; Mari, Nicolas; González-Alonso, Federico; Morelli, Fabiano; Setzer, Alberto; Csiszar, Ivan; Kanpandegi, Jon Ander; Bastarrika, Aitor; Libonati, Renata

2008-01-01

This paper presents results of the AQL2004 project, which has been develope within the GOFC-GOLD Latin American network of remote sensing and forest fires (RedLatif). The project intended to obtain monthly burned-land maps of the entire region, from Mexico to Patagonia, using MODIS (moderate-resolution imaging spectroradiometer) reflectance data. The project has been organized in three different phases: acquisition and preprocessing of satellite data; discrimination of burned pixels; and validation of results. In the first phase, input data consisting of 32-day composites of MODIS 500-m reflectance data generated by the Global Land Cover Facility (GLCF) of the University of Maryland (College Park, Maryland, U.S.A.) were collected and processed. The discrimination of burned areas was addressed in two steps: searching for "burned core" pixels using postfire spectral indices and multitemporal change detection and mapping of burned scars using contextual techniques. The validation phase was based on visual analysis of Landsat and CBERS (China-Brazil Earth Resources Satellite) images. Validation of the burned-land category showed an agreement ranging from 30% to 60%, depending on the ecosystem and vegetation species present. The total burned area for the entire year was estimated to be 153 215 km2. The most affected countries in relation to their territory were Cuba, Colombia, Bolivia, and Venezuela. Burned areas were found in most land covers; herbaceous vegetation (savannas and grasslands) presented the highest proportions of burned area, while perennial forest had the lowest proportions. The importance of croplands in the total burned area should be taken with reserve, since this cover presented the highest commission errors. The importance of generating systematic products of burned land areas for different ecological processes is emphasized.

Design study of long-life PWR using thorium cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subkhi, Moh. Nurul; Su'ud, Zaki; Waris, Abdul

2012-06-06

Design study of long-life Pressurized Water Reactor (PWR) using thorium cycle has been performed. Thorium cycle in general has higher conversion ratio in the thermal spectrum domain than uranium cycle. Cell calculation, Burn-up and multigroup diffusion calculation was performed by PIJ-CITATION-SRAC code using libraries based on JENDL 3.2. The neutronic analysis result of infinite cell calculation shows that {sup 231}Pa better than {sup 237}Np as burnable poisons in thorium fuel system. Thorium oxide system with 8%{sup 233}U enrichment and 7.6{approx} 8%{sup 231}Pa is the most suitable fuel for small-long life PWR core because it gives reactivity swing less than 1%{Delta}k/kmore » and longer burn up period (more than 20 year). By using this result, small long-life PWR core can be designed for long time operation with reduced excess reactivity as low as 0.53%{Delta}k/k and reduced power peaking during its operation.« less

ON THE CHALLENGING VARIABILITY OF LS IV-14{sup 0}116: PULSATIONAL INSTABILITIES EXCITED BY THE {epsilon}-MECHANISM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller Bertolami, M. M.; Corsico, A. H.; Althaus, L. G., E-mail: mmiller@fcaglp.unlp.edu.ar

2011-11-01

We investigate the pulsation driving mechanism responsible for the long-period photometric variations observed in LS IV-14{sup 0}116, a subdwarf B star showing a He-enriched atmospheric composition. To this end, we perform detailed nonadiabatic pulsation computations over fully evolutionary post-He-core-flash stellar structure models, appropriate for hot subdwarf stars at evolutionary phases previous to the He-core burning stage. We found that the variability of LS IV-14{sup 0}116 can be attributed to non-radial g-mode pulsations excited by the {epsilon}-mechanism acting in the He-burning shells that appear before the star settles in the He-core burning stage. Even more interestingly, our results show that LSmore » IV-14{sup 0}116 could be the first known pulsating star in which the {epsilon}-mechanism of mode excitation is operating. Last but not the least, we find that the period range of destabilized modes is sensitive to the exact location of the burning shell, something that might help in distinguishing between the different evolutionary scenarios proposed for the formation of this star.« less

Carbon and nitrogen in Type 2 supernova diamonds

NASA Astrophysics Data System (ADS)

Clayton, Donald D.; Eleid, Mounib; Brown, Lawrence E.

1993-03-01

Abundant diamonds found in meteorites seem either to have condensed within supernova interiors during their expansions and coolings or to have been present around those explosions. Either alternative allows implantation of Xe-HL prior to interstellar mixing. A puzzling feature is the near normalcy of the carbon isotopes, considering that the only C-rich matter, the He-burning shell, is pure C-12 in that region. That last fact has caused many to associate supernova carbon with C-12 carbon, so that its SUNOCONS have been anticipated as very C-12-rich. We show that this expectation is misleading because the C-13-rich regions of Type 2's have been largely overlooked in this thinking. We here follow the idea that the diamonds nucleated in the C-12-rich He shell, the only C-rich site for nucleation, but then attached C-13-rich carbon during turbulent encounters with overlying C-13-rich matter. That is, the initial diamonds continued to grow during the same collisional encounters that cause the Xe-HL implantation. Instead of interacting with the small carbon mass having 13/12 = 0.2 in the upper He zone, however, we have calculated the remnants of the initial H-burning core, which left behind C-13-rich matter as it receded during core hydrogen burning. Howard et al. described why the velocity mixing would be essential to understanding the implantation of both the Xe-H and Xe-L components. Velocity mixing is now known to occur from the X-ray and gamma-ray light curves of supernova 1987A. Using the stellar evolution code developed at Goettingen, we calculated at Clemson the evolution of a grid of massive stars up to the beginning of core He burning. We paid attention to all H-burning reactions throughout the star, to the treatment of both convection and semiconvection, and to the recession of the outer boundary of the convective H-burning core as the star expands toward a larger redder state. This program was to generate a careful map of the CNO isotope distribution as He burning begins. Our result for the 30 solar mass star is shown.

Hollow steel tips for reducing distal fiber burn-back during thulium fiber laser lithotripsy.

PubMed

Hutchens, Thomas C; Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

2013-07-01

The use of thulium fiber laser (TFL) as a potential alternative laser lithotripter to the clinical holmium:YAG laser is being studied. The TFL's Gaussian spatial beam profile provides efficient coupling of higher laser power into smaller core fibers without proximal fiber tip degradation. Smaller fiber diameters are more desirable, because they free up space in the single working channel of the ureteroscope for increased saline irrigation rates and allow maximum ureteroscope deflection. However, distal fiber tip degradation and "burn-back" increase as fiber diameter decreases due to both excessive temperatures and mechanical stress experienced during stone ablation. To eliminate fiber tip burn-back, the distal tip of a 150-μm core silica fiber was glued inside 1-cm-long steel tubing with fiber tip recessed 100, 250, 500, 1000, or 2000 μm inside the steel tubing to create the hollow-tip fiber. TFL pulse energy of 34 mJ with 500-μs pulse duration and 150-Hz pulse rate was delivered through the hollow-tip fibers in contact with human calcium oxalate monohydrate urinary stones during ex vivo studies. Significant fiber tip burn-back and degradation was observed for bare 150-μm core-diameter fibers. However, hollow steel tip fibers experienced minimal fiber burn-back without compromising stone ablation rates. A simple, robust, compact, and inexpensive hollow fiber tip design was characterized for minimizing distal fiber burn-back during the TFL lithotripsy. Although an increase in stone retropulsion was observed, potential integration of the hollow fiber tip into a stone basket may provide rapid stone vaporization, while minimizing retropulsion.

Plasma-wall interaction data needs critical to a Burning Core Experiment (BCX)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-11-01

The Division of Development and Technology has sponsored a four day US-Japan workshop ''Plasma-Wall Interaction Data Needs Critical to a Burning Core Experiment (BCX)'', held at Sandia National Laboratories, Livermore, California on June 24 to 27, 1985. The workshop, which brought together fifty scientists and engineers from the United States, Japan, Germany, and Canada, considered the plasma-material interaction and high heat flux (PMI/HHF) issues for the next generation of magnetic fusion energy devices, the Burning Core Experiment (BCX). Materials options were ranked, and a strategy for future PMI/HHF research was formulated. The foundation for international collaboration and coordination of thismore » research was also established. This volume contains the last three of the five technical sessions. The first of the three is on plasma materials interaction issues, the second is on research facilities and the third is from smaller working group meetings on graphite, beryllium, advanced materials and future collaborations.« less

Investigations into the burning-out of organic substances in the ceramic body

NASA Technical Reports Server (NTRS)

Locher, C.; Pfaff, E.; Schulz, P.; Zografou, C.

1983-01-01

Pressed compacts were made of spray dried alumina containing water soluble polyvinyl alcohol or cellulose derivative binder. The burning out of organic binder on gradual heating was investigated by visual and microscopic observations of the cross section and by thermogravimetry. Burning out proceeds inward from the peripheries, gradually reducing the size of the black core, which first consists of a dark boundary layer and later turns uniformly black with a sharp boundary. A detailed mechanism of the burning out process between and within the spray dried granules is observed under the microscope. Oxygen atmosphere accelerates the burning out process.

Ways to burn more calories every day

MedlinePlus

... change feet. You will work your leg muscles, core muscles, and improve your balance. Put your shoes ... stand: The use of instability to train the core in athletic and nonathletic conditioning. Appl Physiol Nutr ...

Characterization of Gas and Particle Emissions from Laboratory Burns of Peat

EPA Science Inventory

Peat cores collected from two locations in eastern North Carolina (NC, USA) were burned in a laboratory facility to characterize emissions during simulated field combustion. Particle and gas samples were analyzed to quantify emission factors for particulate matter (PM2.5), organi...

Wolf-Rayet stars of type WN/WC and mixing processes during core helium burning of massive stars

NASA Technical Reports Server (NTRS)

Langer, N.

1991-01-01

Consequences of the recent finding that most WN/WC spectra probably originate from individual Wolf-Rayet stars for the internal structure of massive stars are discussed. Numerical models including the effect of slow-down or prevention of convective mixing due to molecular weight gradients are presented, in which a transition layer with a composition mixture of H- and He-burning ashes is formed above the convective He-burning core. These models are able to qualitatively account for the observed WN/WC frequency and agree quantitatively with the only WN/WC-composition determination so far. It is argued that the same transition layer may be responsible for the final blue loop which the SN 1987 A progenitor performed some 10,000 yr before explosion. These results indicate that composition barriers may be efficient in restricting convection during central helium burning, in contrast to computations relying on the Schwarzschild criterion for convection, with or without overshooting.

Stellar evolution with turbulent diffusion. I. A new formalism of mixing.

NASA Astrophysics Data System (ADS)

Deng, L.; Bressan, A.; Chiosi, C.

1996-09-01

In this paper we present a new formulation of diffusive mixing in stellar interiors aimed at casting light on the kind of mixing that should take place in the so-called overshoot regions surrounding fully convective zones. Key points of the analysis are the inclusion the concept of scale length most effective for mixing, by means of which the diffusion coefficient is formulated, and the inclusion of intermittence and stirring, two properties of turbulence known from laboratory fluid dynamics. The formalism is applied to follow the evolution of a 20Msun_ star with composition Z=0.008 and Y=0.25. Depending on the value of the diffusion coefficient holding in the overshoot region, the evolutionary behaviour of the test stars goes from the case of virtually no mixing (semiconvective like structures) to that of full mixing over there (standard overshoot models). Indeed, the efficiency of mixing in this region drives the extension of the intermediate fully convective shell developing at the onset of the the shell H-burning, and in turn the path in the HR Diagram (HRD). Models with low efficiency of mixing burn helium in the core at high effective temperatures, models with intermediate efficiency perform extended loops in the HRD, finally models with high efficiency spend the whole core He-burning phase at low effective temperatures. In order to cast light on this important point of stellar structure, we test whether or not in the regions of the H-burning shell a convective layer can develop. More precisely, we examine whether the Schwarzschild or the Ledoux criterion ought to be adopted in this region. Furthermore, we test the response of stellar models to the kind of mixing supposed to occur in the H-burning shell regions. Finally, comparing the time scale of thermal dissipation to the evolutionary time scale, we get the conclusion that no mixing in this region should occur. The models with intermediate efficiency of mixing and no mixing at all in the shell H-burning regions are of particular interest as they possess at the same time evolutionary characteristics that are separately typical of models calculated with different schemes of mixing. In other words, the new models share the same properties of models with standard overshoot, namely a wider main sequence band, higher luminosity, and longer lifetimes than classical models, but they also possess extended loops that are the main signature of the classical (semiconvective) description of convection at the border of the core.

Stellar evolution of high mass based on the Ledoux criterion for convection

NASA Technical Reports Server (NTRS)

Stothers, R.; Chin, C.

1972-01-01

Theoretical evolutionary sequences of models for stars of 15 and 30 solar masses were computed from the zero-age main sequence to the end of core helium burning. During the earliest stages of core helium depletion, the envelope rapidly expands into the red-supergiant configuration. At 15 solar mass, a blue loop on the H-R diagram ensues if the initial metals abundance, initial helium abundance, or C-12 + alpha particle reaction rate is sufficiently large, or if the 3-alpha reaction rate is sufficiently small. These quantities affect the opacity of the base of the outer convection zone, the mass of the core, and the thermal properties of the core. The blue loop occurs abruptly and fully developed when the critical value of any of these quantities is exceeded, and the effective temperature range and fraction of the lifetime of core helium burning during the slow phase of the blue loop vary surprisingly little. At 30 solar mass no blue loop occurs for any reasonable set of input parameters.

Nuclear Neutrino Spectra in Late Stellar Evolution

NASA Astrophysics Data System (ADS)

Misch, G. Wendell; Sun, Yang; Fuller, George

2018-05-01

Neutrinos are the principle carriers of energy in massive stars, beginning from core carbon burning and continuing through core collapse and after the core bounce. In fact, it may be possible to detect neutrinos from nearby pre-supernova stars. Therefore, it is of great interest to understand the neutrino energy spectra from these stars. Leading up to core collapse, beginning around core silicon burning, nuclei become dominant producers of neutrinos, particularly at high neutrino energy, so a systematic study of nuclear neutrino spectra is desirable. We have done such a study, and we present our sd-shell model calculations of nuclear neutrino energy spectra for nuclei in the mass number range A = 21 - 35. Our study includes neutrinos produced by charged lepton capture, charged lepton emission, and neutral current nuclear deexcitation. Previous authors have tabulated the rates of charged current nuclear weak interactions in astrophysical conditions, but the present work expands on this not only by providing neutrino energy spectra, but also by including the heretofore untabulated neutral current de-excitation neutrino pairs.

Relations between soil hydraulic properties and burn severity

USGS Publications Warehouse

Moody, John A.; Ebel, Brian A.; Nyman, Petter; Martin, Deborah A.; Stoof, Cathelijne R.; McKinley, Randy

2015-01-01

Wildfire can affect soil hydraulic properties, often resulting in reduced infiltration. The magnitude of change in infiltration varies depending on the burn severity. Quantitative approaches to link burn severity with changes in infiltration are lacking. This study uses controlled laboratory measurements to determine relations between a remotely sensed burn severity metric (dNBR, change in normalised burn ratio) and soil hydraulic properties (SHPs). SHPs were measured on soil cores collected from an area burned by the 2013 Black Forest fire in Colorado, USA. Six sites with the same soil type were selected across a range of burn severities, and 10 random soil cores were collected from each site within a 30-m diameter circle. Cumulative infiltration measurements were made in the laboratory using a tension infiltrometer to determine field-saturated hydraulic conductivity, Kfs, and sorptivity, S. These measurements were correlated with dNBR for values ranging from 124 (low severity) to 886 (high severity). SHPs were related to dNBR by inverse functions for specific conditions of water repellency (at the time of sampling) and soil texture. Both functions had a threshold value for dNBR between 124 and 420, where Kfs and S were unchanged and equal to values for soil unaffected by fire. For dNBRs >~420, the Kfs was an exponentially decreasing function of dNBR and S was a linearly decreasing function of dNBR. These initial quantitative empirical relations provide a first step to link SHPs to burn severity, and can be used in quantitative infiltration models to predict post-wildfire infiltration and resulting runoff.

The wound/burn guidelines - 6: Guidelines for the management of burns.

PubMed

Yoshino, Yuichiro; Ohtsuka, Mikio; Kawaguchi, Masakazu; Sakai, Keisuke; Hashimoto, Akira; Hayashi, Masahiro; Madokoro, Naoki; Asano, Yoshihide; Abe, Masatoshi; Ishii, Takayuki; Isei, Taiki; Ito, Takaaki; Inoue, Yuji; Imafuku, Shinichi; Irisawa, Ryokichi; Ohtsuka, Masaki; Ogawa, Fumihide; Kadono, Takafumi; Kawakami, Tamihiro; Kukino, Ryuichi; Kono, Takeshi; Kodera, Masanari; Takahara, Masakazu; Tanioka, Miki; Nakanishi, Takeshi; Nakamura, Yasuhiro; Hasegawa, Minoru; Fujimoto, Manabu; Fujiwara, Hiroshi; Maekawa, Takeo; Matsuo, Koma; Yamasaki, Osamu; Le Pavoux, Andres; Tachibana, Takao; Ihn, Hironobu

2016-09-01

Burns are a common type of skin injury encountered at all levels of medical facilities from private clinics to core hospitals. Minor burns heal by topical treatment alone, but moderate to severe burns require systemic management, and skin grafting is often necessary also for topical treatment. Inappropriate initial treatment or delay of initial treatment may exert adverse effects on the subsequent treatment and course. Therefore, accurate evaluation of the severity and initiation of appropriate treatment are necessary. The Guidelines for the Management of Burn Injuries were issued in March 2009 from the Japanese Society for Burn Injuries as guidelines concerning burns, but they were focused on the treatment for extensive and severe burns in the acute period. Therefore, we prepared guidelines intended to support the appropriate diagnosis and initial treatment for patients with burns that are commonly encountered including minor as well as moderate and severe cases. Because of this intention of the present guidelines, there is no recommendation of individual surgical procedures. © 2016 Japanese Dermatological Association.

The Remarkable Deaths of 9-11 Solar Mass Stars

NASA Astrophysics Data System (ADS)

Woosley, S. E.; Heger, Alexander

2015-09-01

The post-helium-burning evolution of stars from 7 {M}⊙ to 11 {M}⊙ is complicated by the lingering effects of degeneracy and off-center ignition. Here, stars in this mass range are studied using a standard set of stellar physics. Two important aspects of the study are the direct coupling of a reaction network of roughly 220 nuclei to the structure calculation at all stages and the use of a subgrid model to describe the convective bounded flame that develops during neon and oxygen burning. Below 9.0 {M}⊙ degenerate oxygen-neon cores form that may become either white dwarfs or electron-capture supernovae. Above 10.3 {M}⊙ the evolution proceeds “normally” to iron-core collapse, without composition inversions or degenerate flashes. Emphasis here is upon the stars in between, which typically ignite oxygen burning off-center. After oxygen burns in a convectively bounded flame, silicon burning ignites in a degenerate flash that commences closer to the stellar center and with increasing violence for stars of larger mass. In some cases the silicon flash is so violent that it could lead to the early ejection of the hydrogen envelope. This might have interesting observable consequences. For example, the death of a 10.0 {M}⊙ star could produce two supernova-like displays, a faint low-energy event due to the silicon flash, and an unusually bright supernova many months later as the low-energy ejecta from core collapse collides with the previously ejected envelope. The potential relation to the Crab supernova is discussed.

High latitude Southern Hemisphere fire history during the mid-late Holocene (750- 6000 yr BP)

USGS Publications Warehouse

Battistel, Dario; Kehrwald, Natalie; Zennaro, Piero; Pellegrino, Giuseppe; Barbaro, Elena; Zangrando, Roberta; Pedeli, Xanthi X.; Varin, Cristiano; Spolaor, Andrea; Vallelonga, Paul T.; Gambaro, Andrea; Barbante, Carlo

2018-01-01

We determined the specific biomass burning biomarker levoglucosan in an ice core from the TALos Dome Ice CorE drilling project (TALDICE) during the mid- to late Holocene (6000–750 BP). The levoglucosan record is characterized by a long-term increase with higher rates starting at  ∼  4000 BP and peaks between 2500 and 1500 BP. The anomalous increase in levoglucosan centered at  ∼  2000 BP is consistent with other Antarctic biomass burning records. Multiple atmospheric phenomena affect the coastal Antarctic Talos Dome drilling site, where the Southern Annular Mode (SAM) is the most prominent as the Southern Annular Mode Index (SAMA) correlates with stable isotopes in precipitation throughout the most recent 1000 years of the ice core. If this connection remains throughout the mid- to late Holocene, then our results demonstrate that changes in biomass burning, rather than changes in atmospheric transport, are the major influence on the TALDICE levoglucosan record. Comparisons with charcoal syntheses help evaluate fire sources, showing a greater contribution from southern South American fires than from Australian biomass burning. The levoglucosan peak centered at  ∼  2000 BP occurs during a cool period throughout the Southern Hemisphere, yet during a time of increased fire activity in both northern and southern Patagonia. This peak in biomass burning is influenced by increased vegetation in southern South America from a preceding humid period, in which the vegetation desiccated during the following cool, dry period. The Talos Dome ice core record from 6000 to  ∼  750 BP currently does not provide clear evidence that the fire record may be strongly affected by anthropogenic activities during the mid- to late Holocene, although we cannot exclude at least a partial influence.

Benchmarking of Neutron Flux Parameters at the USGS TRIGA Reactor in Lakewood, Colorado

NASA Astrophysics Data System (ADS)

Alzaabi, Osama E.

The USGS TRIGA Reactor (GSTR) located at the Denver Federal Center in Lakewood Colorado provides opportunities to Colorado School of Mines students to do experimental research in the field of neutron activation analysis. The scope of this thesis is to obtain precise knowledge of neutron flux parameters at the GSTR. The Colorado School of Mines Nuclear Physics group intends to develop several research projects at the GSTR, which requires the precise knowledge of neutron fluxes and energy distributions in several irradiation locations. The fuel burn-up of the new GSTR fuel configuration and the thermal neutron flux of the core were recalculated since the GSTR core configuration had been changed with the addition of two new fuel elements. Therefore, a MCNP software package was used to incorporate the burn up of reactor fuel and to determine the neutron flux at different irradiation locations and at flux monitoring bores. These simulation results were compared with neutron activation analysis results using activated diluted gold wires. A well calibrated and stable germanium detector setup as well as fourteen samplers were designed and built to achieve accuracy in the measurement of the neutron flux. Furthermore, the flux monitoring bores of the GSTR core were used for the first time to measure neutron flux experimentally and to compare to MCNP simulation. In addition, International Atomic Energy Agency (IAEA) standard materials were used along with USGS national standard materials in a previously well calibrated irradiation location to benchmark simulation, germanium detector calibration and sample measurements to international standards.

Measuring ethane and acetylene in Antarctic ice cores to quantify long-term hydrocarbon emissions from tropical fires

NASA Astrophysics Data System (ADS)

Nicewonger, M. R.; Aydin, M.; Prather, M. J.; Saltzman, E. S.

2017-12-01

This study examines ethane (C2H6) and acetylene (C2H2) in polar ice cores in order to reconstruct variations in the atmospheric levels of these trace gases over the past 2,000 years. Both of these non-methane hydrocarbons are released from fossil fuel, biofuel, and biomass burning. Ethane, but not acetylene, is also emitted from natural geologic outgassing of hydrocarbons. In an earlier study, we reported ethane levels in Greenland and Antarctic ice cores showing roughly equal contributions from biomass burning and geologic emissions to preindustrial atmospheric ethane levels (Nicewonger et al., 2016). Here we introduce acetylene as an additional constraint to better quantify preindustrial variations in the emissions from these natural hydrocarbon sources. Here we present 30 new measurements of ethane and acetylene from the WDC-06A ice core from WAIS Divide and the newly drilled South Pole ice core (SPICECORE). Ethane results display a gradual decline from peak levels of 110 ppt at 1400 CE to a minimum of 60-80 ppt during 1700-1875 CE. Acetylene correlates with ethane (r2 > 0.4), dropping from peak levels of 35 ppt at 1400 CE to 15-20 ppt at 1875 CE. The covariance between the two trace gases implies that the observed changes are likely caused by decreasing emissions from low latitude biomass burning. We will discuss results from chemical transport modeling and sensitivity tests and the implications for the preindustrial ethane and acetylene budgets.

Patients' perspectives on quality of life after burn.

PubMed

Kool, Marianne B; Geenen, Rinie; Egberts, Marthe R; Wanders, Hendriët; Van Loey, Nancy E

2017-06-01

The concept quality of life (QOL) refers to both health-related outcomes and one's skills to reach these outcomes, which is not yet incorporated in the burn-related QOL conceptualisation. The aim of this study was to obtain a comprehensive overview of relevant burn-specific domains of QOL from the patient's perspective and to determine its hierarchical structure. Concept mapping was used comprising a focus group (n=6), interviews (n=25), and a card-sorting task (n=24) in burn survivors. Participants sorted aspects of QOL based on content similarity after which hierarchical cluster analysis was used to determine the hierarchical structure of burn-related QOL. Ninety-nine aspects of burn-related QOL were selected from the interviews, written on cards, and sorted. The hierarchical structure of burn-related QOL showed a core distinction between resilience and vulnerability. Resilience comprised the domains positive coping and social sharing. Vulnerability included 5 domains subdivided in 13 subdomains: the psychological domain included trauma-related symptoms, cognitive symptoms, negative emotions, body perception and depressive mood; the economical domain comprised finance and work; the social domain included stigmatisation/invalidation; the physical domain comprised somatic symptoms, scars, and functional limitations; and the intimate/sexual domain comprised the relationship with partner, and anxiety/avoidance in sexual life. From the patient's perspective, QOL following burns includes a variety of vulnerability and resilience factors, which forms a fresh basis for the development of a screening instrument. Whereas some factors are well known, this study also revealed overlooked problem and resilience areas that could be considered in client-centred clinical practice in order to customize self-management support. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Building a balanced scorecard for a burn center.

PubMed

Wachtel, T L; Hartford, C E; Hughes, J A

1999-08-01

The Balanced Scorecard provides a model that can be adapted to the management of any burn center, burn service or burn program. This model enables an organization to translate its mission and vision into specific strategic objectives across the four perspective: (1) the financial perspective; (2) the customer service perspective; (3) the internal business perspective; and (4) the growth and learning perspective. Once the appropriate objectives are identified, the Balanced Scorecard guides the organization to develop reasonable performance measures and establishes targets, initiatives and alternatives to meet programmatic goals and pursue longer-term visionary improvements. We used the burn center at the University of Colorado Health Sciences Center to test whether the Balanced Scorecard methodology was appropriate for the core business plan of a healthcare strategic business unit (i.e. a burn center).

Nonlinear behavior of solar gravity modes driven by He-3 in the core. I - Bifurcation analysis

NASA Technical Reports Server (NTRS)

Merryfield, William J.; Gough, Douglas; Toomre, Juri

1990-01-01

The nonlinear development of solar gravity modes driven by He-3 burning in the solar core is investigated by means of an idealized dynamical model. Possible outcomes that have been suggested in the literature include the triggering of subcritical direct convection, leading to core mixing, and the saturation of the excitation processes, leading to sustained finite-amplitude oscillations. The present simple model suggests that the latter is the more likely. The limiting amplitude of the oscillations is estimated, ignoring possible resonances with other gravity modes, to be of order 10 km/s at the solar surface. Such oscillations would be easily observable. That large-amplitude gravity modes have not been observed suggests either that these modes are not unstable in the present era or that they are limited to much smaller amplitudes by resonant coupling.

Comparative analysis of thorium and uranium fuel for transuranic recycle in a sodium cooled Fast Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. Fiorina; N. E. Stauff; F. Franceschini

2013-12-01

The present paper compares the reactor physics and transmutation performance of sodium-cooled Fast Reactors (FRs) for TRansUranic (TRU) burning with thorium (Th) or uranium (U) as fertile materials. The 1000 MWt Toshiba-Westinghouse Advanced Recycling Reactor (ARR) conceptual core has been used as benchmark for the comparison. Both burner and breakeven configurations sustained or started with a TRU supply, and assuming full actinide homogeneous recycle strategy, have been developed. State-of-the-art core physics tools have been employed to establish fuel inventory and reactor physics performances for equilibrium and transition cycles. Results show that Th fosters large improvements in the reactivity coefficients associatedmore » with coolant expansion and voiding, which enhances safety margins and, for a burner design, can be traded for maximizing the TRU burning rate. A trade-off of Th compared to U is the significantly larger fuel inventory required to achieve a breakeven design, which entails additional blankets at the detriment of core compactness as well as fuel manufacturing and separation requirements. The gamma field generated by the progeny of U-232 in the U bred from Th challenges fuel handling and manufacturing, but in case of full recycle, the high contents of Am and Cm in the transmutation fuel impose remote fuel operations regardless of the presence of U-232.« less

Modeling Smoke Plume-Rise and Dispersion from Southern United States Prescribed Burns with Daysmoke

Treesearch

G L Achtemeier; S L Goodrick; Y Liu; F Garcia-Menendez; Y Hu; M. Odman

2011-01-01

We present Daysmoke, an empirical-statistical plume rise and dispersion model for simulating smoke from prescribed burns. Prescribed fires are characterized by complex plume structure including multiple-core updrafts which makes modeling with simple plume models difficult. Daysmoke accounts for plume structure in a three-dimensional veering/sheering atmospheric...

ASTEROSEISMOLOGY OF THE NEARBY SN II PROGENITOR RIGEL. II. {epsilon}-MECHANISM TRIGGERING GRAVITY-MODE PULSATIONS?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moravveji, Ehsan; Moya, Andres; Guinan, Edward F., E-mail: moravveji@iasbs.ac.ir

2012-04-10

The cores of luminous B- and A-type (BA) supergiant stars are the seeds of later core-collapse supernovae. Thus, constraining the near-core conditions in this class of stars can place tighter constraints on the size, mass, and chemical composition of supernova remnants. Asteroseismology of these massive stars is one possible approach into such investigations. Recently, Moravveji et al. in 2012 (hereafter Paper I) extracted 19 significant frequencies from a 6-year radial velocity monitoring of Rigel ({beta} Ori, B8 Ia). The periods they determined broadly range from 1.22 to 74.74 days. Based on our differentially rotating stellar structure and evolution model, Rigel,more » at its current evolutionary state, is undergoing core He burning and shell H burning. Linear fully non-adiabatic non-radial stability analyses result in the excitation of a dense spectrum of non-radial gravity-dominated mixed modes. The fundamental radial mode (l = 0) and its overtones are all stable. When the hydrogen-burning shell is located even partially in the radiative zone, a favorable condition for destabilization of g-modes through the so-called {epsilon}-mechanism becomes viable. Only those g-modes that have high relative amplitudes in the hydrogen-burning (radiative) zone can survive the strong radiative damping. From the entire observed range of variability periods of Rigel (found in Paper I), and based on our model, only those modes with periods ranging between 21 and 127 days can be theoretically explained by the {epsilon}-mechanism. The origin of the short-period variations (found in Paper I) still remains unexplained. Because Rigel is similar to other massive BA supergiants, we believe that the {epsilon}-mechanism may be able to explain the long-period variations in {alpha} Cygni class of pulsating stars.« less

A hybrid rocket engine design for simple low cost sounding rocket use

NASA Astrophysics Data System (ADS)

Grubelich, Mark; Rowland, John; Reese, Larry

1993-06-01

Preliminary test results on a nitrous oxide/HTPB hybrid rocket engine suitable for powering a small sounding rocket to altitudes of 50-100 K/ft are presented. It is concluded that the advantage of the N2O hybrid engine over conventional solid propellant rocket motors is the ability to obtain long burn times with core burning geometries due to the low regression rate of the fuel. Long burn times make it possible to reduce terminal velocity to minimize air drag losses.

Numerical Simulation of Turbulent Combustion Using Vortex Methods

DTIC Science & Technology

1988-09-27

laminar burning velocity times the flame length measured along the line of maximum reaction rate. Following the burning of the eddy core, the strain...is approximately the same as the flame length at t - 0. In the second stage, and as the eddy starts to roll up, the flame front forms a fold within the...Rp, which is the slope of the curve in Fig. 9, can be approximated by the product of the flame length times the average burning velocity along the

Influence of arc current and pressure on non-chemical equilibrium air arc behavior

NASA Astrophysics Data System (ADS)

Yi, WU; Yufei, CUI; Jiawei, DUAN; Hao, SUN; Chunlin, WANG; Chunping, NIU

2018-01-01

The influence of arc current and pressure on the non-chemical equilibrium (non-CE) air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non-equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together—convection, diffusion and chemical reactions—influence non-CE behavior.

Neutrino emission from nearby supernova progenitors

NASA Astrophysics Data System (ADS)

Yoshida, Takashi; Takahashi, Koh; Umeda, Hideyuki

2016-05-01

Neutrinos have an important role for energy loss process during advanced evolution of massive stars. Although the luminosity and average energy of neutrinos during the Si burning are much smaller than those of supernova neutrinos, these neutrinos are expected to be detected by the liquid scintillation neutrino detector KamLAND if a supernova explosion occurs at the distance of ~100 parsec. We investigate the neutrino emission from massive stars during advanced evolution. We calculate the evolution of the energy spectra of neutrinos produced through electron-positron pair-annihilation in the supernova progenitors with the initial mass of 12, 15, and 20 M ⊙ during the Si burning and core-collapse stages. The neutrino emission rate increases from ~ 1050 s-1 to ~ 1052 s-1. The average energy of electron-antineutrinos is about 1.25 MeV during the Si burning and gradually increases until the core-collapse. For one week before the supernova explosion, the KamLAND detector is expected to observe 12-24 and 6-13 v¯e events in the normal and inverted mass hierarchies, respectively, if a supernova explosion of a 12-20 M ⊙ star occurs at the distance of 200 parsec, corresponding to the distance to Betelgeuse. Observations of neutrinos from SN progenitors have a possibility to constrain the core structure and the evolution just before the core collapse of massive stars.

The feasibility study of small long-life gas cooled fast reactor with mixed natural Uranium/Thorium as fuel cycle input

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ariani, Menik; Su'ud, Zaki; Waris, Abdul

2012-06-06

A conceptual design study of Gas Cooled Fast Reactors with Modified CANDLE burn-up scheme has been performed. In this study, design GCFR with Helium coolant which can be continuously operated by supplying mixed Natural Uranium/Thorium without fuel enrichment plant or fuel reprocessing plant. The active reactor cores are divided into two region, Thorium fuel region and Uranium fuel region. Each fuel core regions are subdivided into ten parts (region-1 until region-10) with the same volume in the axial direction. The fresh Natural Uranium and Thorium is initially put in region-1, after one cycle of 10 years of burn-up it ismore » shifted to region-2 and the each region-1 is filled by fresh natural Uranium/Thorium fuel. This concept is basically applied to all regions in both cores area, i.e. shifted the core of i{sup th} region into i+1 region after the end of 10 years burn-up cycle. For the next cycles, we will add only Natural Uranium and Thorium on each region-1. The calculation results show the reactivity reached by mixed Natural Uranium/Thorium with volume ratio is 4.7:1. This reactor can results power thermal 550 MWth. After reactor start-up the operation, furthermore reactor only needs Natural Uranium/Thorium supply for continue operation along 100 years.« less

Comparison of Available Soil Nitrogen Assays in Control and Burned Forested Sites

Treesearch

Jennifer D. Knoepp; Wayne T. Swank

1995-01-01

The existence of several different methods for measuring net Nmineralization and nitrilkation rates and indexing N availability has raised questions about the comparability of these methods. We compared in situ covered cores, in situ buried bags, aerobic laboratory incubations, and tension lysimetry on control and treated plots of a prescribed burn experiment in the...

Fuel burnup analysis for IRIS reactor using MCNPX and WIMS-D5 codes

NASA Astrophysics Data System (ADS)

Amin, E. A.; Bashter, I. I.; Hassan, Nabil M.; Mustafa, S. S.

2017-02-01

International Reactor Innovative and Secure (IRIS) reactor is a compact power reactor designed with especial features. It contains Integral Fuel Burnable Absorber (IFBA). The core is heterogeneous both axially and radially. This work provides the full core burn up analysis for IRIS reactor using MCNPX and WIMDS-D5 codes. Criticality calculations, radial and axial power distributions and nuclear peaking factor at the different stages of burnup were studied. Effective multiplication factor values for the core were estimated by coupling MCNPX code with WIMS-D5 code and compared with SAS2H/KENO-V code values at different stages of burnup. The two calculation codes show good agreement and correlation. The values of radial and axial powers for the full core were also compared with published results given by SAS2H/KENO-V code (at the beginning and end of reactor operation). The behavior of both radial and axial power distribution is quiet similar to the other data published by SAS2H/KENO-V code. The peaking factor values estimated in the present work are close to its values calculated by SAS2H/KENO-V code.

Convection Destroys the Core/Mantle Structure in Hybrid C/O/Ne White Dwarfs

NASA Astrophysics Data System (ADS)

Brooks, Jared; Schwab, Josiah; Bildsten, Lars; Quataert, Eliot; Paxton, Bill

2017-01-01

A hybrid C/O/Ne white dwarf (WD)—an unburned C/O core surrounded by an O/Ne/Na mantle—can be formed if the carbon flame is quenched in a super-AGB star or white dwarf merger remnant. We show that this segregated hybrid structure becomes unstable to rapid mixing within 2000 years of the onset of WD cooling. Carbon burning includes a weak reaction that removes electrons, resulting in a lower electron-to-baryon ratio ({Y}{{e}}) in the regions processed by carbon burning compared to the unburned C/O core, making the O/Ne mantle denser than the C/O core as the WD cools. This is unstable to efficient mixing. We use the results of {\\mathtt{MESA}} models with different size C/O cores to quantify the rate at which the cores mix with the mantle as they cool. In all cases, we find that the WDs undergo significant core/mantle mixing on timescales shorter than the time available to grow the WD to the Chandrasekhar mass (MCh) by accretion. As a result, hybrid WDs that reach MCh due to later accretion will have lower central carbon fractions than assumed thus far. We briefly discuss the implications of these results for the possibility of SNe Ia from hybrid WDs.

Postwildfire measurement of soil physical and hydraulic properties at selected sampling sites in the 2011 Las Conchas wildfire burn scar, Jemez Mountains, north-central New Mexico

USGS Publications Warehouse

Romero, Orlando C.; Ebel, Brian A.; Martin, Deborah A.; Buchan, Katie W.; Jornigan, Alanna D.

2018-04-10

The generation of runoff and the resultant flash flooding can be substantially larger following wildfire than for similar rainstorms that precede wildfire disturbance. Flash flooding after the 2011 Las Conchas Fire in New Mexico provided the motivation for this investigation to assess postwildfire effects on soil-hydraulic properties (SHPs) and soil-physical properties (SPPs) as a function of remotely sensed burn severity 4 years following the wildfire. A secondary purpose of this report is to illustrate a methodology to determine SHPs that analyzes infiltrometer data by using three different analysis methods. The SPPs and SHPs are measured as a function of remotely sensed burn severity by using the difference in the Normalized Burn Ratio (dNBR) metric for seven sites. The dNBR metric was used to guide field sample collection across a full spectrum of burn severities that covered the range of Monitoring Trends in Burn Severity (MTBS) and Burned Area Reflectance Classification (BARC) thematic classes from low to high severity. The SPPs (initial and saturated soil-water content, bulk density, soil-organic matter, and soil-particle size) and SHPs (field-saturated hydraulic conductivity and sorptivity) were measured under controlled laboratory conditions for soil cores collected in the field. The SHPs were estimated by using tension infiltrometer measurements and three different data analysis methods. These measurements showed large effects of burn severity, focused in the top1 centimeter (cm) of soil, on some SPPs (bulk density, soil organic matter, and particle sizes). The threshold of these bulk density and soil organic matter effects was between 300 and 400 dNBR, which corresponds to a MTBS thematic class between moderate and high burn severity and a BARC4 thematic class of high severity. Gravel content and the content of fines in the top 1 cm of soil had a higher threshold value between 450 and 500 dNBR. Lesser effects on SPPs were observed at depths of 1–3 cm and 3–6 cm. In contrast, SHPs showed little effect from dNBR or from MTBS/BARC4 thematic class. Measurements suggested that 4 years of elapsed time after the wildfire may be sufficient for SHP recovery in this area. These measurements also indicated that SPP differences as a function of burn severity cannot be used as reliable indicators of SHP differences as a function of burn severity.

Conceptual Designing of a Reduced Moderation Pressurized Water Reactor by Use of MVP and MVP-BURN

NASA Astrophysics Data System (ADS)

Kugo, T.

A conceptual design of a seed-blanket assembly PWR core with a complicated geometry and a strong heterogeneity has been carried forward by use of the continuous-energy Monte Carlo method. Through parametric survey calculations by repeated use of MVP and a lattice burn-up calculation by MVP-BURN, a seed-blanket assembly configuration suitable for a concept of RMWR has been established, by evaluating precisely reactivity, a conversion ratio and a coolant void reactivity coefficient in a realistic computation time on a super computer.

The Geoland2 BioPar burned area product

NASA Astrophysics Data System (ADS)

Tansey, K.; Bradley, A.; Smets, B.; van Best, C.; Lacaze, R.

2012-04-01

The European Commission Geoland2 project intends to constitute a major step forward to the implementation of the GMES Land Monitoring Core Service (LMCS). The Bio-geophysical Parameters (BioPar) Core Monitoring Service aims at setting-up pre-operational infrastructures for providing regional, European, and global bio-geophysical variables, both in near real time and off-line mode, for describing the vegetation state, the radiation budget at the surface, and the water cycle. The burned area product is part of the BioPar portfolio. The burned area product further builds on the experience of the Global Burned Area (GBA2000) and L3JRC projects. In the GBA2000 project, several algorithms were developed for different geographical regions of the world, and applied to a 1-year time series (the year 2000) of SPOT-VEGETATION data. In the L3JRC project, a single algorithm was improved and applied to a 7-year global dataset of SPOT-VEGETATION data. Since the conception of the Geoland2 project, work has been undertaken to improve the L3JRC algorithm, mainly based on user comments and feedback. Furthermore, the Geoland2 burned area product specification has been developed to meet the requirements of the Core Information Service, specifically LandCarbon and Natural Resource Monitoring in Africa (Narma). The Geoland2 burned area product has the following improvements over the L3JRC product: • It resolves issues with users extracting statistics and burned area estimates for time periods considered to be outside the main seasons for burning. Specifically, this deals with issues in northern latitude winters. • The number of pre-processing steps has been shortened, reducing processing time. • An improved land-water mask has been used. This resolves a problem around the coastlines of land masses which were frequently being detected as being burned. • A season metric calculation is performed over a 1x1 degree grid. For each grid cell, a date is logged against the start of the fire season, peak of the fire season and then the end of the fire season. Once a fire season has been confirmed as being finished, the region effectively resets itself, which means that the land surface can burn again when the next fire season starts. This automated season reset feature enables multiple fire seasons to be analysed. • Provides easy to interpret seasonality tables every 10 days (the reporting period for the product). It is intended that the product will be validated using CEOS-approved protocols and data sets currently being developed through the European Space Agency Fire-CCI project. In this paper, initial results being produced operationally and will be presented along with examples highlighting the performance of the seasonality metric.

Co-production of Nitrogen-15 and Oxygen-18 in Explosive Helium Burning and Implications for Supernova Graphite Grains

NASA Astrophysics Data System (ADS)

Bojazi, Michael

My Masters research involves simulations of a supernova whereby a shock wave of constant Mach number is sent through a 15-solar-mass star evolved to the point of core-collapse. The resulting nucleosynthesis is examined with the intent of explaining the overproduction, relative to solar values, of nitrogen-15 and oxygen-18 abundances in supernova presolar graphite grains, as experimentally determined by Groopman et al. via a NanoSIMS analysis. We find such overabundances to be present in the helium-rich zone. Oxygen-18 is leftover from presupernova helium burning while nitrogen-15 is produced by explosive helium burning. Interestingly, anomalous excesses in molybdenum-95 and molybdenum-97 abundances in SiC X grains, discovered by Pellin et al. using the CHARISMA instrument, probably arise from explosive helium burning as well. These results signal the importance of the helium-rich zone for supernova presolar grain growth. We suggest that matter deep from the supernova, which is rich in iron-peak elements, gets injected into the helium-rich zone. Small TiC grains form in this material. These subgrains then traverse the helium-rich zone and serve as seeds for the growth of the graphite or SiC X grains.

A Method of Mapping Burned Area Using Chinese FengYun-3 MERSI Satellite Data

NASA Astrophysics Data System (ADS)

Shan, T.

2017-12-01

Wildfire is a naturally reoccurring global phenomenon which has environmental and ecological consequences such as effects on the global carbon budget, changes to the global carbon cycle and disruption to ecosystem succession. The information of burned area is significant for post disaster assessment, ecosystems protection and restoration. The Medium Resolution Spectral Imager (MERSI) onboard FENGYUN-3C (FY-3C) has shown good ability for fire detection and monitoring but lacks recognition among researchers. In this study, an automated burned area mapping algorithm was proposed based on FY-3C MERSI data. The algorithm is generally divided into two phases: 1) selection of training pixels based on 1000-m resolution MERSI data, which offers more spectral information through the use of more vegetation indices; and 2) classification: first the region growing method is applied to 1000-m MERSI data to calculate the core burned area and then the same classification method is applied to the 250-m MERSI data set by using the core burned area as a seed to obtain results at a finer spatial resolution. An evaluation of the performance of the algorithm was carried out at two study sites in America and Canada. The accuracy assessment and validation were made by comparing our results with reference results derived from Landsat OLI data. The result has a high kappa coefficient and the lower commission error, indicating that this algorithm can improve the burned area mapping accuracy at the two study sites. It may then be possible to use MERSI and other data to fill the gaps in the imaging of burned areas in the future.

Enhanced light absorption due to the mixing state of black carbon in fresh biomass burning emissions

NASA Astrophysics Data System (ADS)

Wang, Qiyuan; Cao, Junji; Han, Yongming; Tian, Jie; Zhang, Yue; Pongpiachan, Siwatt; Zhang, Yonggang; Li, Li; Niu, Xinyi; Shen, Zhenxing; Zhao, Zhuzi; Tipmanee, Danai; Bunsomboonsakul, Suratta; Chen, Yang; Sun, Jian

2018-05-01

A lack of information on the radiative effects of refractory black carbon (rBC) emitted from biomass burning is a significant gap in our understanding of climate change. A custom-made combustion chamber was used to simulate the open burning of crop residues and investigate the impacts of rBC size and mixing state on the particles' optical properties. Average rBC mass median diameters ranged from 141 to 162 nm for the rBC produced from different types of crop residues. The number fraction of thickly-coated rBC varied from 53 to 64%, suggesting that a majority of the freshly emitted rBC were internally mixed. By comparing the result of observed mass absorption cross-section to that calculated with Mie theory, large light absorption enhancement factors (1.7-1.9) were found for coated particles relative to uncoated cores. These effects were strongly positively correlated with the percentage of coated particles but independent of rBC core size. We suggest that rBC from open biomass burning may have strong impact on air pollution and radiative forcing immediately after their production.

The association between hypothermia, prehospital cooling, and mortality in burn victims.

PubMed

Singer, Adam J; Taira, Breena R; Thode, Henry C; McCormack, Jane E; Shapiro, Mark; Aydin, Ani; Lee, Christopher

2010-04-01

Hypothermia is associated with increased morbidity and mortality in trauma victims. The prognostic value of hypothermia on emergency department (ED) presentation in burn victims is not well known. The objective of this study was to determine the incidence of hypothermia in burn victims and its association with mortality and hospital length of stay (LOS). The study also examined the potential causative role of prehospital cooling in hypothermic burn patients. This was a retrospective review of a county trauma registry. The county was both suburban and rural, with a population of 1.5 million and with one burn center. Burn patients between 1994 and 2007 who met trauma registry criteria were included. Demographic and clinical data including prehospital cooling, burn size and depth, and presence of inhalation injury were collected. Hypothermia was defined as a core body temperature of less than or equal to 35 degrees C. Data analysis consisted of univariate associations between patient characteristics and hypothermia. There were 1,215 burn patients from 1994 to 2007. Mean age (+/-standard deviation [+/-SD]) was 29 (+/-24) years, 67% were male, 248 (26.7%) had full-thickness burns, and 24 (2.6%) had inhalation injury. Only 17 (1.8%) had a burn larger than 70% total body surface area (TBSA). A total of 929 (76%) patients had an initial ED temperature recorded. Only 15/929 (1.6%) burn patients had hypothermia on arrival, and all were mild (lowest temperature was 32.6 degrees C). There was no association between sex, year, and presence of inhalation injury with hypothermia. Hypothermic patients were older (44 years vs. 29 years, p = 0.01), and median Injury Severity Score (ISS) was higher (25 vs. 4, p = 0.002) than for nonhypothermic patients. Hypothermia was present in 6/17 (35%) patients with a TBSA of 70% or greater and in 8/869 (0.9%) patients with a TBSA of <70% (p < 0.001). Mortality was higher in hypothermic patients (60% vs. 3%, p < 0.001). None of the hypothermic patients received prehospital cooling. Hypothermia on presentation to the ED was noted in 1.6% of all burn victims in this trauma registry. Hypothermia was more common in very large burns and was associated with high mortality. In this series, prehospital cooling did not appear to contribute to hypothermia.

Evolution and nucleosynthesis of extremely metal-poor and metal-free low- and intermediate-mass stars. II. s-process nucleosynthesis during the core He flash

NASA Astrophysics Data System (ADS)

Campbell, S. W.; Lugaro, M.; Karakas, A. I.

2010-11-01

Context. Models of primordial and hyper-metal-poor stars that have masses similar to the Sun are known to experience an ingestion of protons into the hot core during the core helium flash phase at the end of their red giant branch evolution. This produces a concurrent secondary flash powered by hydrogen burning that gives rise to further nucleosynthesis in the core. Aims: We aim to model the nucleosynthesis occurring during the proton ingestion event to ascertain if any significant neutron-capture nucleosynthesis occurs. Methods: We perform post-process nucleosynthesis calculations on a one-dimensional stellar evolution calculation of a star with mass 1 M_⊙ and a metallicity of [Fe/H] = -6.5 that suffers a proton ingestion episode. Our network includes 320 nuclear species and 2366 reactions and treats mixing and burning simultaneously. Results: We find that the mixing and burning of protons into the hot convective core leads to the production of 13C, which then burns via the 13C(α, n)16O reaction, releasing a large number of free neutrons. During the first two years of neutron production the neutron poison 14N abundance is low, allowing the prodigious production of heavy elements such as strontium, barium, and lead via slow neutron captures (the s process). These nucleosynthetic products are later carried to the stellar surface and ejected via stellar winds. We compare our results with observations of the hyper-metal-poor halo star HE 1327-2326, which shows a strong Sr overabundance. Conclusions: Our model provides the possibility of self-consistently explaining the Sr overabundance in HE 1327-2326 together with its C, N, and O overabundances (all within a factor of ˜ ~4) if the material were heavily diluted, for example, via mass transfer in a wide binary system. The model produces at least 18 times too much Ba than observed, but this may be within the large modelling uncertainties. In this scenario, binary systems of low mass must have formed in the early Universe. If this is true, it puts constraints on the primordial initial mass function.

Measurement of nonvolatile particle number size distribution

NASA Astrophysics Data System (ADS)

Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

2016-01-01

An experimental methodology was developed to measure the nonvolatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a nonvolatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol (OA; 40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a nonvolatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

Measurement of non-volatile particle number size distribution

NASA Astrophysics Data System (ADS)

Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

2015-06-01

An experimental methodology was developed to measure the non-volatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a non-volatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol, OA (40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a non-volatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon (BC) with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

STRUCTURAL GLITCHES NEAR THE CORES OF RED GIANTS REVEALED BY OSCILLATIONS IN G-MODE PERIOD SPACINGS FROM STELLAR MODELS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunha, M. S.; Avelino, P. P.; Stello, D.

2015-06-01

With recent advances in asteroseismology it is now possible to peer into the cores of red giants, potentially providing a way to study processes such as nuclear burning and mixing through their imprint as sharp structural variations—glitches—in the stellar cores. Here we show how such core glitches can affect the oscillations we observe in red giants. We derive an analytical expression describing the expected frequency pattern in the presence of a glitch. This formulation also accounts for the coupling between acoustic and gravity waves. From an extensive set of canonical stellar models we find glitch-induced variation in the period spacingmore » and inertia of non-radial modes during several phases of red giant evolution. Significant changes are seen in the appearance of mode amplitude and frequency patterns in asteroseismic diagrams such as the power spectrum and the échelle diagram. Interestingly, along the red giant branch glitch-induced variation occurs only at the luminosity bump, potentially providing a direct seismic indicator of stars in that particular evolution stage. Similarly, we find the variation at only certain post-helium-ignition evolution stages, namely, in the early phases of helium core burning and at the beginning of helium shell burning, signifying the asymptotic giant branch bump. Based on our results, we note that assuming stars to be glitch-free, while they are not, can result in an incorrect estimate of the period spacing. We further note that including diffusion and mixing beyond classical Schwarzschild could affect the characteristics of the glitches, potentially providing a way to study these physical processes.« less

THE THREE-DIMENSIONAL EVOLUTION TO CORE COLLAPSE OF A MASSIVE STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Couch, Sean M.; Chatzopoulos, Emmanouil; Arnett, W. David

2015-07-20

We present the first three-dimensional (3D) simulation of the final minutes of iron core growth in a massive star, up to and including the point of core gravitational instability and collapse. We capture the development of strong convection driven by violent Si burning in the shell surrounding the iron core. This convective burning builds the iron core to its critical mass and collapse ensues, driven by electron capture and photodisintegration. The non-spherical structure and motion generated by 3D convection is substantial at the point of collapse, with convective speeds of several hundreds of km s{sup −1}. We examine the impactmore » of such physically realistic 3D initial conditions on the core-collapse supernova mechanism using 3D simulations including multispecies neutrino leakage and find that the enhanced post-shock turbulence resulting from 3D progenitor structure aids successful explosions. We conclude that non-spherical progenitor structure should not be ignored, and should have a significant and favorable impact on the likelihood for neutrino-driven explosions. In order to make simulating the 3D collapse of an iron core feasible, we were forced to make approximations to the nuclear network making this effort only a first step toward accurate, self-consistent 3D stellar evolution models of the end states of massive stars.« less

A New Mass Criterium for Electron Capture Supernovae

NASA Astrophysics Data System (ADS)

Poelarends, Arend

2016-06-01

Electron capture supernovae (ECSN) are thought to populate the mass range between massive white dwarf progenitors and core collapse supernovae. It is generally believed that the initial stellar mass range for ECSN from single stars is about 0.5-1.0 M⊙ wide and centered around a value of 8.5 or 9 M⊙, depending on the specifics of the physics of convection and mass loss one applies. Since mass loss in a binary system is able to delay or cancel the second dredge-up, it is also believed that the initial mass range for ECSN in binary systems is wider than in single stars, but an initial mass range has not been defined yet.The last phase of stars in this particular mass range, however, is challenging to compute, either due to recurring Helium shell flashes, or due to convectively bound flames in the degenerate interior of the star. It would be helpful, nevertheless, to know before we enter these computationally intensive phases whether a star will explode as an ECSN or not. The mass of the helium core after helium core burning is one such criterium (Nomoto, 1984), which predicts that ECSN will occur if the helium core mass is between 2.0 M⊙ and 2.5 M⊙. However, since helium cores can be subject to erosion due to mass loss — even during helium core burning, this criterium will not yield accurate predictions for stars in binary systems.We present a dense grid of stellar evolution models that allow us to put constraints on the final fate of their cores, based on a combination of Carbon/Oxygen core mass, the mass of the surrounding Helium layer and C/O abundance. We find that CO cores with masses between 1.365 and 1.420 M⊙ at the end of Carbon burning will result in ECSN, with some minor adjustments of these ranges due to the mass of the Helium layer and the C/O ratio. While detailed models of stars within the ECSN mass range remain necessary to understand the details of pre-ECSN evolution, our research refines the Helium core criterion and provides a useful way to determine the final fate of stars in this complicated mass range early on.

Engineering and Physics Optimization of Breed and Burn Fast Reactor Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael J. Driscoll; Pavel Hejzlar; Peter Yarsky

2005-12-09

This project is organized under four major tasks (each of which has two or more subtasks) with contributions among the three collaborating organizations (MIT, INEEL and ANL-West): Task A: Core Physics and Fuel Cycle; Task B: Core Thermal Hydraulics; Task C: Plant Design Task; and D: Fuel Design.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geier, S.; Classen, L.; Heber, U., E-mail: geier@sternwarte.uni-erlangen.de

Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very thin hydrogen envelopes. In order to form an sdB, the progenitor has to lose almost all of its hydrogen envelope right at the tip of the red-giant branch. In binary systems, mass transfer to the companion provides the extraordinary mass loss required for their formation. However, apparently single sdBs exist as well and their formation has been unclear for decades. The merger of helium white dwarfs (He-WDs) leading to an ignition of core helium burning or the merger of a helium core and a low-mass star during themore » common envelope phase have been proposed as processes leading to sdB formation. Here we report the discovery of EC 22081-1916 as a fast-rotating, single sdB star of low gravity. Its atmospheric parameters indicate that the hydrogen envelope must be unusually thick, which is at variance with the He-WD merger scenario, but consistent with a common envelope merger of a low-mass, possibly substellar object with a red-giant core.« less

Fire, Climate, and Human Activity: A Combustive Combination

NASA Astrophysics Data System (ADS)

Kehrwald, N. M.; Battistel, D.; Argiriadis, E.; Barbante, C.; Barber, L. B.; Fortner, S. K.; Jasmann, J.; Kirchgeorg, T.; Zennaro, P.

2017-12-01

Ice and lake core records demonstrate that fires caused by human activity can dominate regional biomass burning records in the Common Era. These major increases in fires are often associated with extensive land use change such as an expansion in agriculture. Regions with few humans, relatively stable human populations and/or unvarying land use often have fire histories that are dominated by climate parameters such as temperature and precipitation. Here, we examine biomass burning recorded in ice cores from northern Greenland (NEEM, (77°27'N; 51°3.6'W), Alaska (Juneau Icefield, 58° 35' N; 134° 29'W) and East Antarctica (EPICA DOME C; 75°06'S; 123°21'E), along with New Zealand lake cores to investigate interactions between climate, fire and human activity. Biomarkers such as levoglucosan, and its isomers mannosan and galactosan, can only be produced by cellulose combustion and therefore are specific indicators of past fire activity archived in ice and lake cores. These fire histories add another factor to climate proxies from the same core, and provide a comparison to regional fire syntheses from charcoal records and climate models. For example, fire data from the JSBACH-Spitfire model for the past 2000 years demonstrates that a climate-only scenario would not increase biomass burning in high northern latitudes for the past 2000 years, while NEEM ice core and regional pollen records demonstrate both increased fire activity and land use change that may be ascribed to human activity. Additional biomarkers such as fecal sterols in lake sediments can determine when people were in an area, and can help establish if an increased human presence in an area corresponds with intensified fire activity. This combination of specific biomarkers, other proxy data, and model output can help determine the relative impact of humans versus climate factors on regional fire activity.

Geologic, geotechnical, and geophysical properties of core from the Acme Fire-Pit-1 drill hole, Sheridan County, Wyoming

USGS Publications Warehouse

Collins, Donley S.

1983-01-01

A preliminary core study from the Acme Fire-Pit-1 drill hole, Sheridan County, Wyoming, revealed that the upper portion of the core had been baked by a fire confined to the underlying Monarch coal bed. The baked (clinkered) sediment above the Monarch coal bed was determined to have higher point-load strength values (greater than 2 MPa) than the sediment under the burned coal

Thermonuclear runaways in nova outbursts

NASA Technical Reports Server (NTRS)

Shankar, Anurag; Arnett, David; Fryxell, Bruce A.

1992-01-01

Results of exploratory, two-dimensional numerical calculations of a local thermonuclear runaway on the surface of a white dwarf are reported. It is found that the energy released by the runaway can induce a significant amount of vorticity near the burning region. Such mass motions account naturally for mixing of core matter into the envelope during the explosion. A new mechanism for the lateral spread of nuclear burning is also discussed.

A century of Amazon burning driven by Atlantic climate

NASA Astrophysics Data System (ADS)

Makou, M.; Thompson, L. G.; Davis, M. E.; Eglinton, T. I.

2011-12-01

Very little is known about annual burning trends in the Amazon Basin prior to remote sensing of fires beginning in the late 1970's. Fires reduce Amazon forest biomass and species richness, release pollutant aerosols, and impact the carbon cycle, compelling further investigation of fire-climate dynamics. We measured organic compounds derived from vegetation burning in ice core samples from the Quelccaya Ice Cap in Peru at better than annual resolution to reconstruct wet and dry season burning throughout the Twentieth Century. Variations in the abundance of methyl hexadecanoate, which is produced by thermal alteration of vascular plant alkanoic acids, were used as a proxy for past fire activity. Concentrations of this compound in Quelccaya ice varied strongly on seasonal, interannual, and decadal time scales over the last 100 years, with high-amplitude dry season variability and muted, decadal-scale changes in wet season fire activity. Decade-long periods of repeatedly enhanced burning occurred during the 1930's and 1960's when dry season precipitation was perpetually reduced, as evidenced by low stages of the Rio Negro. These decadal trends suggest that changes in dry season precipitation drive fire activity in the western Amazon and highlight the potential of Amazon forests to undergo repeated strong burning. Fires occurred during years when sea surface temperatures (SSTs) in the north tropical Atlantic were elevated and the north-south tropical Atlantic SST gradient was enhanced; this SST pattern likely displaced the intertropical convergence zone northward, driving subsidence and drought in the western and southern Amazon basin. Thus, our novel ice core record suggests that Amazon forest fire activity during the Twentieth Century was driven primarily by Atlantic climate processes, and future forest health will depend heavily on the evolution of tropical climate.

Comparing ambient, air-convection, and fluid-convection heating techniques in treating hypothermic burn patients, a clinical RCT

PubMed Central

2011-01-01

Background Hypothermia in burns is common and increases morbidity and mortality. Several methods are available to reach and maintain normal core body temperature, but have not yet been evaluated in critical care for burned patients. Our unit's ordinary technique for controlling body temperature (Bair Hugger®+ radiator ceiling + bed warmer + Hotline®) has many drawbacks e.g.; slow and the working environment is hampered. The aim of this study was to compare our ordinary heating technique with newly-developed methods: the Allon™2001 Thermowrap (a temperature regulating water-mattress), and Warmcloud (a temperature regulating air-mattress). Methods Ten consecutive burned patients (> 20% total burned surface area and a core temperature < 36.0°C) were included in this prospective, randomised, comparative study. Patients were randomly exposed to 3 heating methods. Each treatment/measuring-cycle lasted for 6 hours. Each heating method was assessed for 2 hours according to a randomised timetable. Core temperature was measured using an indwelling (bladder) thermistor. Paired t-tests were used to assess the significance of differences between the treatments within the patients. ANOVA was used to assess the differences in temperature from the first to the last measurement among all treatments. Three-way ANOVA with the Tukey HSD post hoc test and a repeated measures ANOVA was used in the same manner, but included information about patients and treatment/measuring-cycles to control for potential confounding. Data are presented as mean (SD) and (range). Probabilities of less than 0.05 were accepted as significant. Results The mean increase, 1.4 (SD 0.6°C; range 0.6-2.6°C) in core temperature/treatment/measuring-cycle highly significantly favoured the Allon™2001 Thermowrap in contrast to the conventional method 0.2 (0.6)°C (range -1.2 to 1.5°C) and the Warmcloud 0.3 (0.4)°C (range -0.4 to 0.9°C). The procedures for using the Allon™2001 Thermowrap were experienced to be more comfortable and straightforward than the conventional method or the Warmcloud. Conclusions The Allon™2001 Thermowrap was more effective than the Warmcloud or the conventional method in controlling patients' temperatures. PMID:21736717

Size distribution and mixing state of black carbon particles during a heavy air pollution episode in Shanghai

NASA Astrophysics Data System (ADS)

Gong, Xianda; Zhang, Ci; Chen, Hong; Nizkorodov, Sergey A.; Chen, Jianmin; Yang, Xin

2016-04-01

A Single Particle Aerosol Mass Spectrometer (SPAMS), a Single Particle Soot Photometer (SP2) and various meteorological instruments were employed to investigate the chemical and physical properties of black carbon (BC) aerosols during a regional air pollution episode in urban Shanghai over a 5-day period in December 2013. The refractory black carbon (rBC) mass concentrations measured by SP2 averaged 3.2 µg m-3, with the peak value of 12.1 µg m-3 at 04:26 LT on 7 December. The number of BC-containing particles captured by SPAMS in the size range 200-1200 nm agreed very well with that detected by SP2 (R2 = 0.87). A cluster analysis of the single particle mass spectra allowed for the separation of BC-containing particles into five major classes: (1) Pure BC; (2) BC attributed to biomass burning (BBBC); (3) K-rich BC-containing (KBC); (4) BC internally mixed with OC and ammonium sulfate (BCOC-SOx); (5) BC internally mixed with OC and ammonium nitrate (BCOC-NOx). The size distribution of internally mixed BC particles was bimodal. Detected by SP2, the condensation mode peaked around ˜ 230 nm and droplet mode peaked around ˜ 380 nm, with a clear valley in the size distribution around ˜ 320 nm. The condensation mode mainly consisted of traffic emissions, with particles featuring a small rBC core (˜ 60-80 nm) and a relatively thin absolute coating thickness (ACT, ˜ 50-130 nm). The droplet mode included highly aged traffic emission particles and biomass burning particles. The biomass burning particles had a larger rBC core (˜ 80-130 nm) and a thick ACT (˜ 110-300 nm). The highly aged traffic emissions had a smaller core (˜ 60-80 nm) and a very thick ACT (˜ 130-300 nm), which is larger than reported in any previous literature. A fast growth rate (˜ 20 nm h-1) of rBC with small core sizes was observed during the experiment. High concentrations pollutants like NO2 likely accelerated the aging process and resulted in a continuous size growth of rBC-containing particles from traffic emission.

An extended version of the SERPENT-2 code to investigate fuel burn-up and core material evolution of the Molten Salt Fast Reactor

NASA Astrophysics Data System (ADS)

Aufiero, M.; Cammi, A.; Fiorina, C.; Leppänen, J.; Luzzi, L.; Ricotti, M. E.

2013-10-01

In this work, the Monte Carlo burn-up code SERPENT-2 has been extended and employed to study the material isotopic evolution of the Molten Salt Fast Reactor (MSFR). This promising GEN-IV nuclear reactor concept features peculiar characteristics such as the on-line fuel reprocessing, which prevents the use of commonly available burn-up codes. Besides, the presence of circulating nuclear fuel and radioactive streams from the core to the reprocessing plant requires a precise knowledge of the fuel isotopic composition during the plant operation. The developed extension of SERPENT-2 directly takes into account the effects of on-line fuel reprocessing on burn-up calculations and features a reactivity control algorithm. It is here assessed against a dedicated version of the deterministic ERANOS-based EQL3D procedure (PSI-Switzerland) and adopted to analyze the MSFR fuel salt isotopic evolution. Particular attention is devoted to study the effects of reprocessing time constants and efficiencies on the conversion ratio and the molar concentration of elements relevant for solubility issues (e.g., trivalent actinides and lanthanides). Quantities of interest for fuel handling and safety issues are investigated, including decay heat and activities of hazardous isotopes (neutron and high energy gamma emitters) in the core and in the reprocessing stream. The radiotoxicity generation is also analyzed for the MSFR nominal conditions. The production of helium and the depletion in tungsten content due to nuclear reactions are calculated for the nickel-based alloy selected as reactor structural material of the MSFR. These preliminary evaluations can be helpful in studying the radiation damage of both the primary salt container and the axial reflectors.

Aromatic acids in a Eurasian Arctic ice core: a 2600-year proxy record of biomass burning

NASA Astrophysics Data System (ADS)

Grieman, Mackenzie M.; Aydin, Murat; Fritzsche, Diedrich; McConnell, Joseph R.; Opel, Thomas; Sigl, Michael; Saltzman, Eric S.

2017-04-01

Wildfires and their emissions have significant impacts on ecosystems, climate, atmospheric chemistry, and carbon cycling. Well-dated proxy records are needed to study the long-term climatic controls on biomass burning and the associated climate feedbacks. There is a particular lack of information about long-term biomass burning variations in Siberia, the largest forested area in the Northern Hemisphere. In this study we report analyses of aromatic acids (vanillic and para-hydroxybenzoic acids) over the past 2600 years in the Eurasian Arctic Akademii Nauk ice core. These compounds are aerosol-borne, semi-volatile organic compounds derived from lignin combustion. The analyses were made using ion chromatography with electrospray mass spectrometric detection. The levels of these aromatic acids ranged from below the detection limit (0.01 to 0.05 ppb; 1 ppb = 1000 ng L-1) to about 1 ppb, with roughly 30 % of the samples above the detection limit. In the preindustrial late Holocene, highly elevated aromatic acid levels are observed during three distinct periods (650-300 BCE, 340-660 CE, and 1460-1660 CE). The timing of the two most recent periods coincides with the episodic pulsing of ice-rafted debris in the North Atlantic known as Bond events and a weakened Asian monsoon, suggesting a link between fires and large-scale climate variability on millennial timescales. Aromatic acid levels also are elevated during the onset of the industrial period from 1780 to 1860 CE, but with a different ratio of vanillic and para-hydroxybenzoic acid than is observed during the preindustrial period. This study provides the first millennial-scale record of aromatic acids. This study clearly demonstrates that coherent aromatic acid signals are recorded in polar ice cores that can be used as proxies for past trends in biomass burning.

Core-shell carbon nanosphere-TiO2 composite and hollow TiO2 nanospheres prepared by atomic layer deposition

NASA Astrophysics Data System (ADS)

Bakos, L. P.; Justh, N.; Hernádi, K.; Kiss, G.; Réti, B.; Erdélyi, Z.; Parditka, B.; Szilágyi, I. M.

2016-10-01

Core-shell carbon-TiO2 composite and hollow TiO2 nanospheres were prepared using carbon nanospheres as hard-templates, coating them with TiO2 using atomic layer deposition, and subsequent burning out of the carbon cores. The bare carbon, the composite carbon-TiO2 and the hollow TiO2 nanospheres were characterized with TG/DTA-MS, FTIR, XRD and SEM-EDX.

Environment-based pin-power reconstruction method for homogeneous core calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leroyer, H.; Brosselard, C.; Girardi, E.

2012-07-01

Core calculation schemes are usually based on a classical two-step approach associated with assembly and core calculations. During the first step, infinite lattice assemblies calculations relying on a fundamental mode approach are used to generate cross-sections libraries for PWRs core calculations. This fundamental mode hypothesis may be questioned when dealing with loading patterns involving several types of assemblies (UOX, MOX), burnable poisons, control rods and burn-up gradients. This paper proposes a calculation method able to take into account the heterogeneous environment of the assemblies when using homogeneous core calculations and an appropriate pin-power reconstruction. This methodology is applied to MOXmore » assemblies, computed within an environment of UOX assemblies. The new environment-based pin-power reconstruction is then used on various clusters of 3x3 assemblies showing burn-up gradients and UOX/MOX interfaces, and compared to reference calculations performed with APOLLO-2. The results show that UOX/MOX interfaces are much better calculated with the environment-based calculation scheme when compared to the usual pin-power reconstruction method. The power peak is always better located and calculated with the environment-based pin-power reconstruction method on every cluster configuration studied. This study shows that taking into account the environment in transport calculations can significantly improve the pin-power reconstruction so far as it is consistent with the core loading pattern. (authors)« less

Transuranic Waste Burning Potential of Thorium Fuel in a Fast Reactor - 12423

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wenner, Michael; Franceschini, Fausto; Ferroni, Paolo

Westinghouse Electric Company (referred to as 'Westinghouse' in the rest of this paper) is proposing a 'back-to-front' approach to overcome the stalemate on nuclear waste management in the US. In this approach, requirements to further the societal acceptance of nuclear waste are such that the ultimate health hazard resulting from the waste package is 'as low as reasonably achievable'. Societal acceptability of nuclear waste can be enhanced by reducing the long-term radiotoxicity of the waste, which is currently driven primarily by the protracted radiotoxicity of the transuranic (TRU) isotopes. Therefore, a transition to a more benign radioactive waste can bemore » accomplished by a fuel cycle capable of consuming the stockpile of TRU 'legacy' waste contained in the LWR Used Nuclear Fuel (UNF) while generating waste which is significantly less radio-toxic than that produced by the current open U-based fuel cycle (once through and variations thereof). Investigation of a fast reactor (FR) operating on a thorium-based fuel cycle, as opposed to the traditional uranium-based is performed. Due to a combination between its neutronic properties and its low position in the actinide chain, thorium not only burns the legacy TRU waste, but it does so with a minimal production of 'new' TRUs. The effectiveness of a thorium-based fast reactor to burn legacy TRU and its flexibility to incorporate various fuels and recycle schemes according to the evolving needs of the transmutation scenario have been investigated. Specifically, the potential for a high TRU burning rate, high U-233 generation rate if so desired and low concurrent production of TRU have been used as metrics for the examined cycles. Core physics simulations of a fast reactor core running on thorium-based fuels and burning an external TRU feed supply have been carried out over multiple cycles of irradiation, separation and reprocessing. The TRU burning capability as well as the core isotopic content have been characterized. Results will be presented showing the potential for thorium to reach a high TRU transmutation rate over a wide variety of fuel types (oxide, metal, nitride and carbide) and transmutation schemes (recycle or partition of in-bred U-233). In addition, a sustainable scheme has been devised to burn the TRU accumulated in the core inventory once the legacy TRU supply has been exhausted, thereby achieving long-term virtually TRU-free. A comprehensive 'back-to-front' approach to the fuel cycle has recently been proposed by Westinghouse which emphasizes achieving 'acceptable', low-radiotoxicity, high-level waste, with the intent not only to satisfy all technical constraints but also to improve public acceptance of nuclear energy. Following this approach, the thorium fuel cycle, due to its low radiotoxicity and high potential for TRU transmutation has been selected as a promising solution. Additional studies not shown here have shown significant reduction of decay heat. The TRU burning potential of the Th-based fuel cycle has been illustrated with a variety of fuel types, using the Toshiba ARR to perform the analysis, including scenarios with continued LWR operation of either uranium fueled or thorium fueled LWRs. These scenarios will afford overall reduction in actinide radiotoxicity, however when the TRU supply is exhausted, a continued U- 235 LWR operation must be assumed to provide TRU makeup feed. This scenario will never reach the characteristically low TRU content of a closed thorium fuel cycle with its associated potential benefits on waste radiotoxicity, as exemplified by the transition scenario studied. At present, the cases studied indicate ThC as a potential fuel for maximizing TRU burning, while ThN with nitrogen enriched to 95% N-15 shows the highest breeding potential. As a result, a transition scenario with ThN was developed to show that a sustainable, closed Th-cycle can be achieved starting from burning the legacy TRU stock and completing the transmutation of the residual TRU remaining in the core inventory after the legacy TRU external supply has been exhausted. The radiotoxicity of the actinide waste during the various phases has been characterized, showing the beneficial effect of the decreasing content of TRU in the recycled fuel as the transition to a closed Th-based fuel cycle is undertaken. Due to the back-to-front nature of the proposed methodology, detailed designs are not the first step taken when assessing a fuel cycle scenario potential. As a result, design refinement is still required and should be expected in future studies. Moreover, significant safety assessment, including determination of associated reactivity coefficients, fuel and reprocessing feasibility studies and economic assessments will still be needed for a more comprehensive and meaningful comparison against other potential solutions. With the above considerations in mind, the potential advantages of thorium fuelled reactors on HLW management optimization lead us to believe that thorium fuelled reactor systems can play a significant role in the future and deserve further consideration. (authors)« less

Is burnout related to allostatic load?

PubMed

Langelaan, Saar; Bakker, Arnold B; Schaufeli, Wilmar B; van Rhenen, Willem; van Doornen, Lorenz J P

2007-01-01

Burnout has a negative impact on physical health, but the mechanisms underlying this relation remain unclear. To elucidate these mechanisms, possible mediating physiological systems or risk factors for adverse health in burned-out employees should be investigated. The aim of the present study among 290 Dutch managers was to explore whether allostatic load mediates the relationship between burnout and physical health. Burned-out managers, as identified with the Maslach Burnout Inventory General Survey (MBI-GS), were compared with a healthy control group with regard to their allostatic load. The allostatic load index included eight parameters: Body-mass index (BMI), systolic and diastolic blood pressure (SBP and DBP), C-reactive protein (CRP), high-density lipoprotein (HDL), cholesterol, glycosylated hemoglobin (HbA1C) and glucose. Contrary to expectations, burned-out managers did not differ from healthy managers with regard to their scores on the allostatic load index. An additional analysis, using groups of managers in the extreme deciles of exhaustion (the core symptom of burnout), did also not reveal differences in allostatic load. Burnout seems not to be associated with this proxy measure of allostatic load. The mediating physiological mechanisms between burnout and objective physical health remain to be elucidated.

The subdwarf B star SB 290 - A fast rotator on the extreme horizontal branch

NASA Astrophysics Data System (ADS)

Geier, S.; Heber, U.; Heuser, C.; Classen, L.; O'Toole, S. J.; Edelmann, H.

2013-03-01

Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very thin hydrogen envelopes. To form an sdB, the progenitor has to lose almost all of its hydrogen envelope right at the tip of the red giant branch. In close binary systems, mass transfer to the companion provides the extraordinary mass loss required for their formation. However, apparently single sdBs exist as well, and their formation has been unclear for decades. The merger of helium white dwarfs leading to an ignition of core helium-burning or the merger of a helium core and a low-mass star during the common envelope phase have been proposed. Here we report the discovery of SB 290 as the first apparently single, fast-rotating sdB star located on the extreme horizontal branch, indicating that those stars may form from mergers. Appendix A is available in electronic form at http://www.aanda.org

Magnetic braking of stellar cores in red giants and supergiants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maeder, André; Meynet, Georges, E-mail: andre.maeder@unige, E-mail: georges.meynet@unige.ch

2014-10-01

Magnetic configurations, stable on the long term, appear to exist in various evolutionary phases, from main-sequence stars to white dwarfs and neutron stars. The large-scale ordered nature of these fields, often approximately dipolar, and their scaling according to the flux conservation scenario favor a fossil field model. We make some first estimates of the magnetic coupling between the stellar cores and the outer layers in red giants and supergiants. Analytical expressions of the truncation radius of the field coupling are established for a convective envelope and for a rotating radiative zone with horizontal turbulence. The timescales of the internal exchangesmore » of angular momentum are considered. Numerical estimates are made on the basis of recent model grids. The direct magnetic coupling of the core to the extended convective envelope of red giants and supergiants appears unlikely. However, we find that the intermediate radiative zone is fully coupled to the core during the He-burning and later phases. This coupling is able to produce a strong spin down of the core of red giants and supergiants, also leading to relatively slowly rotating stellar remnants such as white dwarfs and pulsars. Some angular momentum is also transferred to the outer convective envelope of red giants and supergiants during the He-burning phase and later.« less

[Influence of educational status, burn area and coping behaviors on the complication of psychological disorders in severely burned patients].

PubMed

Cheng, Hua; Li, Xiao-jian; Cao, Wen-juan; Chen, Li-ying; Zhang, Zhi; Liu, Zhi-he; Yi, Xian-feng; Lai, Wen

2013-04-01

To discuss how the educational status, burn area and coping behaviors influence the psychological disorders in severely burned patients. Sixty-four severely burned patients hospitalized in Guangzhou Red Cross Hospital, Guangdong Provincial Work Injury Rehabilitation Center, and Guangdong General Hospital were enrolled with cluster random sampling method. Data of their demography and situation of burns were collected. Then their coping behavior, psychological disorders including anxiety, depression and post-traumatic stress disorder (PTSD) plus its core symptoms of flashback, avoidance, and hypervigilance were assessed by medical coping modes questionnaire, self-rating anxiety scale (SAS), self-rating depression scale (SDS), PTSD checklist-civilian version (PCL-C) respectively. Correlation was analyzed between demography, burn area, coping behavior and psychological disorders. The predictive powers of educational status, burn area and coping behaviors on the psychological disorders were analyzed. The qualitative variables were assigned values. Data were processed with t test, Spearman rank correlation analysis, and multiple linear regression analysis. (1) The patients scored (19.0 ± 3.4) points in confrontation coping behavior, which showed no statistically significant difference from the domestic norm score (19.5 ± 3.8) points (t = -1.13, P > 0.05). The patients scored (16.6 ± 2.4) and (11.0 ± 2.2) points in avoidance and resignation coping behaviors, which were significantly higher than the domestic norm score (14.4 ± 3.0), (8.8 ± 3.2) points (with t values respectively 7.06 and 7.76, P values both below 0.01). The patients' standard score of SAS, SDS, PCL-C were (50 ± 11), (54 ± 11), and (38 ± 12) points. Respectively 89.1% (57/64), 60.9% (39/64), 46.9% (30/64) of the patients showed anxiety, depression, and PTSD symptoms. (2) Four independent variables: age, gender, marital status, and time after burns, were correlated with the psychological disorders, but the correlativity was not statistically significant (with rs values from -0.089 to 0.245, P values all above 0.05). Educational status was significantly negatively correlated with anxiety, depression, PTSD and its core symptoms of flashback, avoidance (with rs values from -0.361 to -0.253, P values all below 0.05). Educational status was negatively correlated with hypervigilance, but the correlativity was not statistically significant (rs = -0.187, P > 0.05). Burn area was significantly positively correlated with the psychological disorders (with rs values from 0.306 to 0.478, P values all below 0.05). Confrontation coping behavior was positively correlated with the psychological disorders, but the correlativity was not statistically significant (with rs values from 0.121 to 0.550, P values all above 0.05). Avoidance coping behavior was correlated with the psychological disorders, but the correlativity was not statistically significant (with rs values from -0.144 to 0.193, P values all above 0.05). Resignation coping behavior was significantly positively correlated with the psychological disorder (with rs values from 0.377 to 0.596, P values all below 0.01). (3) Educational status had predictive power on the anxiety, PTSD and flash back symptoms of patients (with t values from -2.19 to -2.02, P values all below 0.05), but not on depression, avoidance and hypervigilance (with t values from -1.95 to -0.99, P values all above 0.05). Burn area had no predictive power on the psychological disorders (with t values from 0.55 to 1.78, P values all above 0.05). Resignation coping behavior had predictive power on the psychological disorders (with t values from 3.10 to 6.46, P values below 0.01). Confrontation and avoidance coping behaviors had no predictive power on the psychological disorders (with t values from 0.46 to 2.32 and -0.89 and 1.75 respectively, P values all above 0.05). The severely burned patients with lower educational status, larger burn area, and the more frequently adapted resignation coping behavior are more likely to suffer from anxiety, depression, and PTSD.

Growth Response of Pinus ponderosa following a Mixed-Severity Wildfire in the Black Hills, South Dakota

Treesearch

Tara keyser; Fredrick Smith; Wayne Sheppard

2010-01-01

In late summer 2000 the Jasper Fire burned ~34,000 ha of ponderosa pine forest in the Black Hills of South Dakota. Although regarded as a catastrophic event, the Jasper Fire left a mosaic of fire severity across the landscape, with live trees present in areas burned under low and moderate fire severity. In October 2005, we cored 96 trees from unburned, low-severity,...

Pre-main Sequence Evolution and the Hydrogen-Burning Minimum Mass

NASA Astrophysics Data System (ADS)

Nakano, Takenori

There is a lower limit to the mass of the main-sequence stars (the hydrogen-burning minimum mass) below which the stars cannot replenish the energy lost from their surfaces with the energy released by the hydrogen burning in their cores. This is caused by the electron degeneracy in the stars which suppresses the increase of the central temperature with contraction. To find out the lower limit we need the accurate knowledge of the pre-main sequence evolution of very low-mass stars in which the effect of electron degeneracy is important. We review how Hayashi and Nakano (1963) carried out the first determination of this limit.

Human and climate impacts on Holocene fire activity recorded in polar and mountain ice cores

NASA Astrophysics Data System (ADS)

Kehrwald, Natalie; Zennaro, Piero; Kirchgeorg, Torben; Li, Quanlian; Wang, Ninglian; Power, Mitchell; Zangrando, Roberta; Gabrielli, Paolo; Thompson, Lonnie; Gambaro, Andrea; Barbante, Carlo

2014-05-01

Fire is one of the major influences of biogeochemical change on local to hemispheric scales through emitting greenhouse gases, altering atmospheric chemistry, and changing primary productivity. Levoglucosan (1,6-anhydro-β-D-glucopyranose) is a specific molecular that can only be produced by cellulose burning at temperatures > 300°C, comprises a major component of smoke plumes, and can be transported across > 1000 km distances. Levoglucosan is deposited on and archived in glaciers over glacial interglacial cycles resulting in pyrochemical evidence for exploring interactions between fire, climate and human activity. Ice core records provide records of past biomass burning from regions of the world with limited paleofire data including polar and low-latitude, high-altitude regions. Here, we present Holocene fire activity records from the NEEM, Greenland (77° 27'N; 51° 3'W; 2454 masl), EPICA Dome C, Antarctica (75° 06'S; 123° 21'E; 3233 masl), Kilimanjaro, Tanzania (3° 05'S, 21.2° E, 5893 masl) and the Muztagh, China (87.17° E; 36.35° N; 5780 masl ice cores. The NEEM ice core reflects boreal fire activity from both North American and Eurasian sources. Temperature is the dominant control of NEEM levoglucosan flux over decadal to millennial time scales, while droughts influence fire activity over sub-decadal timescales. Our results demonstrate the prominence of Siberian fire sources during intense multiannual droughts. Unlike the NEEM core, which incorporates the largest land masses in the world as potential fire sources, EPICA Dome C is located far from any possible fire source. However, EPICA Dome C levoglucosan concentrations are consistently above detection limits and demonstrate a substantial 1000-fold increase in fire activity beginning approximately 800 years ago. This significant and sustained increase coincides with Maori arrival and dispersal in New Zealand augmented by later European arrival in Australia. The EPICA Dome C levoglucosan profile is similar to regional charcoal compilations from New Zealand and southeastern Australia. Evidence from Kilimanjaro demonstrates a major increase in fire activity centered around 800-1000 years ago, corresponding to both increased temperatures and aridity as recorded in regional lake cores. This peak in fire activity is an order of magnitude higher than at any other time in the record including the most recent period. Environmental and anthropological studies suggest that upslope human migrations have occurred in response to the warmer, drier conditions. Kilimanjaro is surrounded by flammable savanna vegetation, yet the Muztagh core is located in an especially arid section of the Tibetan Plateau and consistently contains levoglucosan concentrations that are 100 to 1000 times greater than the mean Kilimanjaro flux. These high concentrations and the lack of available fuel suggest that regional rather than local biomass burning may be the source of the fire products. Biomass burning aerosols are a major component of the South Asian Brown Cloud and may influence the composition and concentration of pyrogenic aerosols across the Tibetan Plateau. The relative impact of human activity versus climate change on Holocene biomass burning varies regionally. Combining ice and sediment core data with model output can help place these regional differences into a global context with implications for a warming climate.

Network analysis of wildfire transmission and implications for risk governance

PubMed Central

Ager, Alan A.; Evers, Cody R.; Day, Michelle A.; Preisler, Haiganoush K.; Barros, Ana M. G.; Nielsen-Pincus, Max

2017-01-01

We characterized wildfire transmission and exposure within a matrix of large land tenures (federal, state, and private) surrounding 56 communities within a 3.3 million ha fire prone region of central Oregon US. Wildfire simulation and network analysis were used to quantify the exchange of fire among land tenures and communities and analyze the relative contributions of human versus natural ignitions to wildfire exposure. Among the land tenures examined, the area burned by incoming fires averaged 57% of the total burned area. Community exposure from incoming fires ignited on surrounding land tenures accounted for 67% of the total area burned. The number of land tenures contributing wildfire to individual communities and surrounding wildland urban interface (WUI) varied from 3 to 20. Community firesheds, i.e. the area where ignitions can spawn fires that can burn into the WUI, covered 40% of the landscape, and were 5.5 times larger than the combined area of the community core and WUI. For the major land tenures within the study area, the amount of incoming versus outgoing fire was relatively constant, with some exceptions. The study provides a multi-scale characterization of wildfire networks within a large, mixed tenure and fire prone landscape, and illustrates the connectivity of risk between communities and the surrounding wildlands. We use the findings to discuss how scale mismatches in local wildfire governance result from disconnected planning systems and disparate fire management objectives among the large landowners (federal, state, private) and local communities. Local and regional risk planning processes can adopt our concepts and methods to better define and map the scale of wildfire risk from large fire events and incorporate wildfire network and connectivity concepts into risk assessments. PMID:28257416

Network analysis of wildfire transmission and implications for risk governance.

PubMed

Ager, Alan A; Evers, Cody R; Day, Michelle A; Preisler, Haiganoush K; Barros, Ana M G; Nielsen-Pincus, Max

2017-01-01

We characterized wildfire transmission and exposure within a matrix of large land tenures (federal, state, and private) surrounding 56 communities within a 3.3 million ha fire prone region of central Oregon US. Wildfire simulation and network analysis were used to quantify the exchange of fire among land tenures and communities and analyze the relative contributions of human versus natural ignitions to wildfire exposure. Among the land tenures examined, the area burned by incoming fires averaged 57% of the total burned area. Community exposure from incoming fires ignited on surrounding land tenures accounted for 67% of the total area burned. The number of land tenures contributing wildfire to individual communities and surrounding wildland urban interface (WUI) varied from 3 to 20. Community firesheds, i.e. the area where ignitions can spawn fires that can burn into the WUI, covered 40% of the landscape, and were 5.5 times larger than the combined area of the community core and WUI. For the major land tenures within the study area, the amount of incoming versus outgoing fire was relatively constant, with some exceptions. The study provides a multi-scale characterization of wildfire networks within a large, mixed tenure and fire prone landscape, and illustrates the connectivity of risk between communities and the surrounding wildlands. We use the findings to discuss how scale mismatches in local wildfire governance result from disconnected planning systems and disparate fire management objectives among the large landowners (federal, state, private) and local communities. Local and regional risk planning processes can adopt our concepts and methods to better define and map the scale of wildfire risk from large fire events and incorporate wildfire network and connectivity concepts into risk assessments.

Observations and modelling of enhanced AOD at Spitsbergen - long-range transport of biomass burning emissions from Alaska fires in July 2015

NASA Astrophysics Data System (ADS)

Struzewska, Joanna; Kaminski, Jacek W.; Markowicz, Krzysztof; Lisok, Justyna

2017-04-01

In the scope of the IAREA project (http://www.igf.fuw.edu.pl/iAREA) several measurement campaigns were undertaken at Svalbard in order to assess the variability of absorbing aerosols in this region during spring and summertime 2014-2016. During the summer campaign of 2015 a significant increase of aerosol concentrations and AOD were observed at NyAlesund station from 9 to 15 of July. This episode was connected with the long range transport of smoke plum emitted from biomass burning at Alaska. A tropospheric chemistry model GEM-AQ (Global Environmental Multiscale Air Quality) was used to analyse the pathways and vertical distribution of the biomass burning aerosol observed over Svalbard. The core of the model is based on a weather prediction model with environmental processes (chemistry and aerosols) implanted on-line and are interactive (i.e. providing feedback of chemistry on radiation and dynamics). Aerosol module includes 5 size-resolved types of aerosols: sulphates, black carbon, organic carbon, sea salt and mineral dust. Aerosol mass is distributed into 12 logarithmically spaced bins. Anthropogenic emissions developed by NILU in the ECLIPSE project were used for this study. Biomass burning emissions were applied using daily GFAS fields obtained from the Copernicus Services. We will present the GEM-AQ model results and comparison with available measurement. The GEM-AQ model correctly reproduced the inflow of polluted air masses and sharp increase of AOD values. PM10 analysis showed elevated concentration values up to 700 hPa level, with the maximum reaching 35 ppb at 900 hPa. Model analysis showed over Svalbard shows transport of a thick layer with enhanced extinction above the planetary boundary layer.

Sensitivity of alpha-particle-driven Alfvén eigenmodes to q-profile variation in ITER scenarios

NASA Astrophysics Data System (ADS)

Rodrigues, P.; Figueiredo, A. C. A.; Borba, D.; Coelho, R.; Fazendeiro, L.; Ferreira, J.; Loureiro, N. F.; Nabais, F.; Pinches, S. D.; Polevoi, A. R.; Sharapov, S. E.

2016-11-01

A perturbative hybrid ideal-MHD/drift-kinetic approach to assess the stability of alpha-particle-driven Alfvén eigenmodes in burning plasmas is used to show that certain foreseen ITER scenarios, namely the {{I}\\text{p}}=15 MA baseline scenario with very low and broad core magnetic shear, are sensitive to small changes in the background magnetic equilibrium. Slight variations (of the order of 1% ) of the safety-factor value on axis are seen to cause large changes in the growth rate, toroidal mode number, and radial location of the most unstable eigenmodes found. The observed sensitivity is shown to proceed from the very low magnetic shear values attained throughout the plasma core, raising issues about reliable predictions of alpha-particle transport in burning plasmas.

Turbulence in core-collapse supernovae

NASA Astrophysics Data System (ADS)

Radice, David; Abdikamalov, Ernazar; Ott, Christian D.; Mösta, Philipp; Couch, Sean M.; Roberts, Luke F.

2018-05-01

Multidimensional simulations show that non-radial, turbulent, fluid motion is a fundamental component of the core-collapse supernova explosion mechanism. Neutrino-driven convection, the standing accretion shock instability, and relic-perturbations from advanced nuclear burning stages can all impact the outcome of core collapse in a qualitative and quantitative way. Here, we review the current understanding of these phenomena and their role in the explosion of massive stars. We also discuss the role of protoneutron star convection and of magnetic fields in the context of the delayed neutrino mechanism.

Innovative and Advanced Coupled Neutron Transport and Thermal Hydraulic Method (Tool) for the Design, Analysis and Optimization of VHTR/NGNP Prismatic Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahnema, Farzad; Garimeela, Srinivas; Ougouag, Abderrafi

2013-11-29

This project will develop a 3D, advanced coarse mesh transport method (COMET-Hex) for steady- state and transient analyses in advanced very high-temperature reactors (VHTRs). The project will lead to a coupled neutronics and thermal hydraulic (T/H) core simulation tool with fuel depletion capability. The computational tool will be developed in hexagonal geometry, based solely on transport theory without (spatial) homogenization in complicated 3D geometries. In addition to the hexagonal geometry extension, collaborators will concurrently develop three additional capabilities to increase the code’s versatility as an advanced and robust core simulator for VHTRs. First, the project team will develop and implementmore » a depletion method within the core simulator. Second, the team will develop an elementary (proof-of-concept) 1D time-dependent transport method for efficient transient analyses. The third capability will be a thermal hydraulic method coupled to the neutronics transport module for VHTRs. Current advancements in reactor core design are pushing VHTRs toward greater core and fuel heterogeneity to pursue higher burn-ups, efficiently transmute used fuel, maximize energy production, and improve plant economics and safety. As a result, an accurate and efficient neutron transport, with capabilities to treat heterogeneous burnable poison effects, is highly desirable for predicting VHTR neutronics performance. This research project’s primary objective is to advance the state of the art for reactor analysis.« less

Mixing State and Optical Properties of Biomass Burning Aerosol during the SAMBBA 2012 Campaign

NASA Astrophysics Data System (ADS)

Brooke, Jennifer; Brooks, Barbara; McQuaid, Jim; Osborne, Simon

2013-04-01

Emissions of black carbon are a global phenomenon associated with combustion activities with an estimated 40 % of global emissions from biomass burning. These emissions are typically dominated in regional hotspots, such as along the edges of the Amazon Basin, and contribute to the regional air quality and have associated health impacts as well as the global climatic impacts of this major source of black carbon as well as other radiatively active species. New airborne measurements will be presented of biomass burning emissions across the Amazon region from the South AMerican Biomass Burning Analysis (SAMBBA) campaign based at Porto Vehlo, Rondônia, Brazil in September 2012. This airborne campaign aboard the FAAM BAe-146 coincided with the seasonal peak in South American biomass burning emissions, which make up the most dominant source of atmospheric pollutants in the region at this time. SAMBBA included dedicated flights involving in-situ measurements and remote sensing of single plume studies through to multi-plume sampling of smouldering and flaming vegetation fires, regional haze sampling, and measurements of biogenic aerosol and gases across Amazonas. This presentation summarises early findings from the SAMBBA aircraft observations focusing on the relationship between biomass burning aerosol properties; size distributions, aerosol mixing state and optical properties from a suite of instruments onboard the FAAM BAe-146. The interplay of these properties influences the regional radiative balance impacting on weather and climate. The Leeds airborne VACC (Volatile Aerosol Concentration and Composition) instrument is designed to investigate the volatility properties of different aerosol species in order to determine aerosol composition; furthermore it can be used to infer the mixing state of the aerosol. Size distributions measured with the volatility system will be compared with ambient size distribution measurements this allows information on organic coating loadings to be derived. Cases of different aerosol mixing state have been identified from almost entirely externally mixed aerosol with a mono-modal size distribution across the rainforest of Amazonas in contrast to sampled Rondônian regional haze which was identified to be externally mixed with a coated non-volatile core with a volatile mode. Future and ongoing analysis from SAMBBA will improve the knowledge of the regional and climatic implications of biomass burning activities in the Amazon basin which are a significant issue globally.

Geoantineutrino spectrum and slow nuclear burning on the boundary of the liquid and solid phases of the Earth's core

NASA Astrophysics Data System (ADS)

Rusov, V. D.; Pavlovich, V. N.; Vaschenko, V. N.; Tarasov, V. A.; Zelentsova, T. N.; Bolshakov, V. N.; Litvinov, D. A.; Kosenko, S. I.; Byegunova, O. A.

2007-09-01

We give an alternative description of the data produced in the KamLAND experiment. Assuming the existence of a natural nuclear reactor on the boundary of the liquid and solid phases of the Earth's core, a geoantineutrino spectrum is obtained. This assumption is based on the experimental results of V. Anisichkin and his collaborators on the interaction of uranium dioxide and uranium carbide with iron-nickel and silica-alumina melts at high pressure (5-10 GPa) and temperature (1600-2200°C), which led to the proposal of the existence of an actinide shell in the Earth's core. We describe the operating mechanism of this reactor as solitary waves of nuclear burning in 238U and/or 232Th medium, in particular, as neutron fission progressive waves of Feoktistov and/or Teller et al. type. Next, we propose a simplified model for the accumulation and burn-up kinetics in Feoktistov's U-Pu fuel cycle. We also apply this model for numerical simulations of neutron fission wave in a two-phase UO2/Fe medium on the surface of the Earth's solid core. The proposed georeactor model offers a mechanism for the generation of 3He. The 3He/4He distribution in the Earth's interior is calculated, which in turn can be used as a natural quantitative criterion of the georeactor thermal power. Finally, we give a tentative estimation of the geoantineutrino intensity and spectrum on the Earth's surface. For this purpose we use the O'Nions et al. geochemical model of mantle differentiation and crust growth complemented by a nuclear energy source (georeactor with power of 30 TW).

Are annual layers preserved in NorthGRIP Eemian ice?

NASA Astrophysics Data System (ADS)

Kettner, E.; Bigler, M.; Nielsen, M. E.; Steffensen, J. P.; Svensson, A.

2009-04-01

A newly developed setup for continuous flow analysis (CFA) of ice cores in Copenhagen is optimized for high resolution analysis of four components: Soluble sodium (mainly deriving from sea salt), soluble ammonium (related to biological processes and biomass burning events), insoluble dust particles (basically transported from Asian deserts to Greenland), and the electrolytic melt water conductivity (which is a bulk signal for all ionic constituents). Furthermore, we are for the first time implementing a flow cytometer to obtain high quality dust concentration and size distribution profiles based on individual dust particle measurements. Preliminary measurements show that the setup is able to resolve annual layers of 1 cm thickness. Ice flow models predict that annual layers in the Eemian section of the Greenland NorthGRIP ice core (130-115 ka BP) have a thickness of around 1 cm. However, the visual stratigraphy of the ice core indicates that the annual layering in the Eemian section may be disturbed by micro folds and rapid crystal growth. In this case study we will measure the impurity content of an Eemian segment of the NorthGRIP ice core with the new CFA setup. This will allow for a comparison to well-known impurity levels of the Holocene in both Greenland and Antarctic ice and we will attempt to determine if annual layers are still present in the ice.

Hydrodynamic stability and Ti-tracer distribution in low-adiabat OMEGA direct-drive implosions

NASA Astrophysics Data System (ADS)

Joshi, Tirtha R.

We discuss the hydrodynamic stability of low-adiabat OMEGA direct-drive implosions based on results obtained from simultaneous emission and absorption spectroscopy of a titanium tracer added to the target. The targets were deuterium filled, warm plastic shells of varying thicknesses and filling gas pressures with a submicron Ti-doped tracer layer initially located on the inner surface of the shell. The spectral features from the titanium tracer are observed during the deceleration and stagnation phases of the implosion, and recorded with a time integrated spectrometer (XRS1), streaked crystal spectrometer (SSCA) and three gated, multi-monochromatic X-ray imager (MMI) instruments fielded along quasi-orthogonal lines-of-sight. The time-integrated, streaked and gated data show simultaneous emission and absorption spectral features associated with titanium K-shell line transitions but only the MMI data provides spatially resolved information. The arrays of gated spectrally resolved images recorded with MMI were processed to obtain spatially resolved spectra characteristic of annular contour regions on the image. A multi-zone spectroscopic analysis of the annular spatially resolved spectra permits the extraction of plasma conditions in the core as well as the spatial distribution of tracer atoms. In turn, the titanium atom distribution provides direct evidence of tracer penetration into the core and thus of the hydrodynamic stability of the shell. The observations, timing and analysis indicate that during fuel burning the titanium atoms have migrated deep into the core and thus shell material mixing is likely to impact the rate of nuclear fusion reactions, i.e. burning rate, and the neutron yield of the implosion. We have found that the Ti atom number density decreases towards the center in early deceleration phase, but later in time the trend is just opposite, i.e., it increases towards the center of the implosion core. This is in part a consequence of the convergent effect of spherical geometry. The spatial profiles of Ti areal densities in the implosion core are extracted from space-resolved spectra and also evaluated using 1D spherical scaling. The trends are similar to the Ti number density spatial profiles. The areal densities extracted from data and 1D spherical scaling are very comparable in the outer spherical zones of the implosion core but significantly deviate in the innermost zone. We have observed that approximately 85% of the Ti atoms migrate into the hot core, while 15% of the atoms are still on the shell-fuel interface and contributing to the absorption. In addition, a method to extract the hot spot size based on the formation of the absorption feature in a sequence of annular spectra will be discussed. Results and trends are discussed as a function of target shell thickness and filling pressure, and laser pulse shape.

Concept of grouping in partitioning of HLW for self-consistent fuel cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kitamoto, A.; Mulyanto

1993-12-31

A concept of grouping for partitioning of HLW has been developed in order to examine the possibility of a self-consistent fuel recycle. The concept of grouping of radionuclides is proposed herein, such as Group MA1 (MA below Cm), Group MA2 (Cm and higher MA), Group A ({sup 99}Tc and I), Group B (Cs and Sr) and Group R (the partitioned remain of HLW). Group B is difficult to be transmuted by neutron reaction, so a radiation application in an industrial scale should be developed in the future. Group A and Group MA1 can be burned by a thermal reactor, onmore » the other hand Group MA2 should be burned by a fast reactor. P-T treatment can be optimized for the in-core and out-core system, respectively.« less

Predictors of serious bacterial infections in pediatric burn patients with fever.

PubMed

Vyles, David; Sinha, Madhumita; Rosenberg, David I; Foster, Kevin N; Tran, Melissa; Drachman, David

2014-01-01

To determine predictors of serious bacterial infections in pediatric burn patients with fever (core temp ≥38.5°C), the authors conducted a retrospective review of medical records of pediatric (0-18 years) patients admitted to the Arizona Burn Center between 2008 and 2011 with greater than 5% TBSA and inpatient hospitalization for ≥72 hours. The study group comprised patients with a febrile episode during their inpatient stay. Serious bacterial infection (the primary outcome variable) was defined as: bacteremia, urinary tract infection, meningitis (blood, urine, or cerebrospinal fluid culture positive for a pathogen respectively), pneumonia, line, and wound infection. A generalized estimating equation analysis was done to predict the presence or absence of serious bacterial infection. Of 1082 pediatric burn patients hospitalized during the study period, 353 met the study eligibility criteria. A total of 108 patients (30.6%) had at least one fever episode (fever group). No difference in demographic characteristics was noted between the fever and no-fever groups; significant differences were observed for: third-degree TBSA, second-degree TBSA, total operating room visits, length of stay, Injury Severity Score, and death. A total of 47.2% of the patients had one or more episodes of fever with serious bacterial infection. In a generalized estimating equation predictive model, presence of a central line, second-, and third-degree TBSA were predictive of serious bacterial infection in burn patients with fever. In this study, individual clinical variables such as tachypnea and tachycardia were not predictive of serious bacterial infections, but the presence of a central line, and larger TBSA were significant predictors of serious bacterial infections. Younger age (P =.08) and ventilator support (P =.057) also approached significance as predictors of serious bacterial infections.

The Burn Wound Exudate – an under-utilized resource

PubMed Central

Widgerow, Alan D; King, Kassandra; Tussardi, Ilaria Tocco; Banyard, Derek A.; Chiang, Ryan; Awad, Antony; Afzel, Hassan; Bhatnager, Shweta; Melkumyan, Satenik; Wirth, Garrett; Evans, Gregory R.D

2014-01-01

Introduction The burn wound exudate represents the burn tissue microenvironment. Extracting information from the exudate relating to cellular components, signaling mediators and protein content can provide much needed data relating to the local tissue damage, depth of the wound and probable systemic complications. This review examines the scientific data extracted from burn wound exudates over the years and proposes new investigations that will provide useful information from this underutilized resource. Method A literature review was conducted using the electronic database PubMed to search for literature pertaining to burn wound or blister fluid analysis. Key words included burn exudate, blister fluid, wound exudate, cytokine burn fluid, subeschar fluid, cytokine burns, serum cytokines. 32 relevant article were examined and 29 selected as relevant to the review. 3 papers were discarded due to questionable methodology or conclusions. The reports were assessed for their affect on management decisions and diagnostics. Furthermore, traditional blood level analysis of these mediators was made to compare the accuracy of blood versus exudate in burn wound management. Extrapolations are made for new possibilities of burn wound exudate analysis. Results Studies pertaining to burn wound exudate, subeschar fluid and blister fluid analyses may have contributed to burn wound management decisions particularly related to escharectomies and early burn wound excision. In addition, information from these studies have the potential to impact on areas such as healing, scarring, burn wound conversion and burn wound depth analysis. Conclusion Burn wound exudate analysis has proven useful in burn wound management decisions. It appears to offer a far more accurate reflection of the burn wound pathophysiology than the traditional blood/serum investigations undertaken in the past. New approaches to diagnostics and treatment efficacy assessment are possible utilizing data from this fluid. Burn wound exudate is a useful, currently under-utilized resource that is likely to take a more prominent role in burn wound management. PMID:24986597

Study for requirement of advanced long life small modular fast reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tak, Taewoo, E-mail: ttwispy@unist.ac.kr; Choe, Jiwon, E-mail: chi91023@unist.ac.kr; Jeong, Yongjin, E-mail: yjjeong09@unist.ac.kr

2016-01-22

To develop an advanced long-life SMR core concept, the feasibility of the long-life breed-and-burn core concept has been assessed and the preliminary selection on the reactor design requirement such as fuel form, coolant material has been performed. With the simplified cigar-type geometry of 8m-tall CANDLE reactor concept, it has demonstrated the strengths of breed-and-burn strategy. There is a saturation region in the graph for the multiplication factors, which means that a steady breeding is being proceeded along the axial direction. The propagation behavior of the CANDLE core can be also confirmed through the evolution of the axial power profile. Coolantmore » material is expected to have low melting point, density, viscosity and absorption cross section and a high boiling point, specific heat, and thermal conductivity. In this respect, sodium is preferable material for a coolant of this nuclear power plant system. The metallic fuel has harder spectrum compared to the oxide and carbide fuel, which is favorable to increase the breeding and extend the cycle length.« less

Study for requirement of advanced long life small modular fast reactor

NASA Astrophysics Data System (ADS)

Tak, Taewoo; Choe, Jiwon; Jeong, Yongjin; Lee, Deokjung; Kim, T. K.

2016-01-01

To develop an advanced long-life SMR core concept, the feasibility of the long-life breed-and-burn core concept has been assessed and the preliminary selection on the reactor design requirement such as fuel form, coolant material has been performed. With the simplified cigar-type geometry of 8m-tall CANDLE reactor concept, it has demonstrated the strengths of breed-and-burn strategy. There is a saturation region in the graph for the multiplication factors, which means that a steady breeding is being proceeded along the axial direction. The propagation behavior of the CANDLE core can be also confirmed through the evolution of the axial power profile. Coolant material is expected to have low melting point, density, viscosity and absorption cross section and a high boiling point, specific heat, and thermal conductivity. In this respect, sodium is preferable material for a coolant of this nuclear power plant system. The metallic fuel has harder spectrum compared to the oxide and carbide fuel, which is favorable to increase the breeding and extend the cycle length.

Effect of secondary organic aerosol coating thickness on the real-time detection and characterization of biomass-burning soot by two particle mass spectrometers

DOE PAGES

Ahern, Adam T.; Subramanian, Ramachandran; Saliba, Georges; ...

2016-12-22

Biomass burning is a large source of light-absorbing refractory black carbon (rBC) particles with a wide range of morphologies and sizes. The net radiative forcing from these particles is strongly dependent on the amount and composition of non-light-absorbing material internally mixed with the rBC and on the morphology of the mixed particles. Understanding how the mixing state and morphology of biomass-burning aerosol evolves in the atmosphere is critical for constraining the influence of these particles on radiative forcing and climate. We investigated the response of two commercial laser-based particle mass spectrometers, the vacuum ultraviolet (VUV) ablation LAAPTOF and the IRmore » vaporization SP-AMS, to monodisperse biomass-burning particles as we sequentially coated the particles with secondary organic aerosol (SOA) from α-pinene ozonolysis. We studied three mobility-selected soot core sizes, each with a number of successively thicker coatings of SOA applied. Using IR laser vaporization, the SP-AMS had different changes in sensitivity to rBC compared to potassium as a function of applied SOA coatings. We show that this is due to different effective beam widths for the IR laser vaporization region of potassium versus black carbon. The SP-AMS's sensitivity to black carbon (BC) mass was not observed to plateau following successive SOA coatings, despite achieving high OA : BC mass ratios greater than 9. We also measured the ion fragmentation pattern of biomass-burning rBC and found it changed only slightly with increasing SOA mass. The average organic matter ion signal measured by the LAAPTOF demonstrated a positive correlation with the condensed SOA mass on individual particles, despite the inhomogeneity of the particle core compositions. This demonstrates that the LAAPTOF can obtain quantitative mass measurements of aged soot-particle composition from realistic biomass-burning particles with complex morphologies and composition.« less

Effect of secondary organic aerosol coating thickness on the real-time detection and characterization of biomass-burning soot by two particle mass spectrometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahern, Adam T.; Subramanian, Ramachandran; Saliba, Georges

Biomass burning is a large source of light-absorbing refractory black carbon (rBC) particles with a wide range of morphologies and sizes. The net radiative forcing from these particles is strongly dependent on the amount and composition of non-light-absorbing material internally mixed with the rBC and on the morphology of the mixed particles. Understanding how the mixing state and morphology of biomass-burning aerosol evolves in the atmosphere is critical for constraining the influence of these particles on radiative forcing and climate. We investigated the response of two commercial laser-based particle mass spectrometers, the vacuum ultraviolet (VUV) ablation LAAPTOF and the IRmore » vaporization SP-AMS, to monodisperse biomass-burning particles as we sequentially coated the particles with secondary organic aerosol (SOA) from α-pinene ozonolysis. We studied three mobility-selected soot core sizes, each with a number of successively thicker coatings of SOA applied. Using IR laser vaporization, the SP-AMS had different changes in sensitivity to rBC compared to potassium as a function of applied SOA coatings. We show that this is due to different effective beam widths for the IR laser vaporization region of potassium versus black carbon. The SP-AMS's sensitivity to black carbon (BC) mass was not observed to plateau following successive SOA coatings, despite achieving high OA : BC mass ratios greater than 9. We also measured the ion fragmentation pattern of biomass-burning rBC and found it changed only slightly with increasing SOA mass. The average organic matter ion signal measured by the LAAPTOF demonstrated a positive correlation with the condensed SOA mass on individual particles, despite the inhomogeneity of the particle core compositions. This demonstrates that the LAAPTOF can obtain quantitative mass measurements of aged soot-particle composition from realistic biomass-burning particles with complex morphologies and composition.« less

Effects of Burn Injuries on Thermoregulatory and Cardiovascular Responses in Soldiers: Implications for the Standards of Medical Fitness

DTIC Science & Technology

2017-10-01

greater elevation in core temperature during exercise. In exercise-based rehabilitation or physically demanding occupational settings, activities...Military Health System Research 2 Symposium. We have initiated data collection for Aim 1B (assessment of the impact of large/small statue on...resulting in exacerbated elevations in core temperature and greater risk of heat illness during physical activities. Since the capacity for

First-aid with warm water delays burn progression and increases skin survival.

PubMed

Tobalem, M; Harder, Y; Tschanz, E; Speidel, V; Pittet-Cuénod, B; Wettstein, R

2013-02-01

First aid treatment for thermal injuries with cold water removes heat and decreases inflammation. However, perfusion in the ischemic zone surrounding the coagulated core can be compromised by cold-induced vasoconstriction and favor burn progression. The aim of this study is to evaluate the effect of local warming on burn progression in the rat comb burn model. 24 male Wistar rats were randomly assigned to either no treatment (control) or application of cold (17 °C) or warm (37 °C) water applied for 20 min. Evolution of burn depth, interspace necrosis, and microcirculatory perfusion were assessed with histology, planimetry, respectively with Laser Doppler flowmetry after 1 h, as well as 1, 4, and 7 days. Consistent conversion from a superficial to a deep dermal burn within 24 h was obtained in control animals. Warm and cold water significantly delayed burn depth progression, however after 4 days the burn depth was similar in all groups. Interspace necrosis was significantly reduced by warm water treatment (62±4% vs. 69±5% (cold water) and 82±3% (control); p<0.05). This was attributed to the significantly improved perfusion after warming, which was present 1 h after burn induction and was maintained thereafter (103±4% of baseline vs. 91±3% for cold water and 80±2% for control, p<0.05). In order to limit damage after burn injury, burn progression has to be prevented. Besides delaying burn progression, the application of warm water provided an additional benefit by improving the microcirculatory perfusion, which translated into increased tissue survival. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Molecular Markers in the Quelccaya Ice Cap, Peru Describe 20th Century Biomass Burning Variability

NASA Astrophysics Data System (ADS)

Makou, M. C.; Thompson, L. G.; Eglinton, T. I.; Montluçon, D. B.

2007-12-01

Organic geochemical analytical methods were applied to Andean ice core samples, resulting in a multi- molecular biomass burning record spanning 1915 to 2001 AD. The Quelccaya Ice Cap in Peru is situated on the eastern flank of the Andes at 14°S and is well situated to receive aeolian inputs of organic matter derived from Amazonian forest fire events. Compounds of interest, which occur in trace quantities in ice, were recovered by stir bar sorptive extraction and analyzed by gas chromatography/time-of-flight mass spectrometry coupled with thermal desorption. These methods permitted identification and quantitation of numerous biomarkers in sample volumes of as little as 10 ml. At least one wet and dry season sample was analyzed for every year. Observed biomarkers that may be derived from vegetation fires include several polycyclic aromatic hydrocarbons (PAHs), atraric acid, 2-ethylhexyl p-methoxycinnamate, and a range of other aromatic compounds. Abrupt changes in compound abundances were superimposed on decadal variability. Systematic offsets between wet and dry season abundances were not observed, suggesting that the biomass burning signal is not biased by seasonal depositional effects, such as dust delivery. Inputs likely reflect a combination of sources from anthropogenic burning of the Amazon rainforest as well as natural fires related to aridity, and include both high and low elevation vegetation. These compounds and techniques can be applied to older ice in this and other core locations as an independent estimate of aridity.

Fire and grazing regulate belowground processes in tallgrass prairie

USGS Publications Warehouse

Johnson, Loretta C.; Matchett, John R.

2001-01-01

In tallgrass prairie, belowground processes are even more important than in forested systems because aboveground biomass and standing dead litter are periodically removed by frequent fires or grazers. Thus, studies that address factors regulating belowground processes are especially relevant for tallgrass prairie. We predicted that effects of grazing and burning differ belowground and that changes in root productivity caused by burning or grazing provide feedback that affects ecosystem fluxes of C and N. These differences in belowground response should be driven largely by changes in N dynamics and the degree to which burning and grazing affect the pathway and magnitude of N loss and the degree of N limitation in these systems. Fire, the major pathway of N loss in ungrazed tallgrass prairie, should result in reduced net N mineralization and N availability. We expected plants to compensate for increased N limitation by increasing their allocation to roots, as manifested in increased soil respiration and C cycling belowground. In contrast, grazing conserves N in the ecosystem by redistributing the N once contained in grass to labile forms in urine and dung. Thus, we predicted that grazing should increase N cycling rates and N availability to plants. Consequently, grazed plants should be less N limited and should allocate less C to roots and more to shoots. This, in turn, should decrease belowground C cycling, manifested as reduced soil CO2 flux.We explored the roles of grazing and burning on root growth in experimental watersheds at Konza Prairie, Kansas, USA. To assess effects of fire on root productivity, we installed root ingrowth cores in two watersheds without grazers that differ in fire frequency: annually vs. infrequently burned (four years since the last fire). To assess effects of grazing, we installed root ingrowth cores in an annually burned watershed grazed by bison and in fenced controls (exclosures). Within bison “grazing lawns,” root ingrowth cores were installed in lightly and heavily grazed patches. Concurrently, we measured in situ rates of net N mineralization and soil respiration as indices of soil N and C cycling.Annual burning resulted in a 25% increase in root growth compared to the unburned watershed (four years since last fire), as plants compensated for N limitation by increasing allocation to roots. Grazing had the opposite effect: it decreased root growth, especially in heavily grazed patches (∼30% less than in fenced controls). Grazing by ungulates increased N cycling and availability. Therefore, grazed plants, instead of being N limited, experienced C limitation as shoots regrew and plants allocated less C to roots. Interestingly, root ingrowth on the long-term unburned watershed was as low as in lightly grazed patches in the grazed watershed. Thus, seemingly disparate treatments such as infrequent burning (characterized by accumulation of detritus aboveground) and grazing (periodic biomass removal) both had higher levels of N availability than annually burned prairie in the absence of grazers. Root growth in unburned and grazed watersheds must be limited by resources other than N (e.g., C in grazing lawns or light in infrequently burned prairie).Burning and grazing also altered root tissue chemistry in contrasting ways that further accentuated the root growth differences caused by these treatments. Frequent fires lowered substrate quality of roots (C:N = 60), thus increasing N limitation. In contrast, grazing and infrequent burning improved root tissue quality (C:N = 40), promoting faster cycling of N. These large differences in root growth and tissue chemistry can result in profound ecosystem-level changes. Grazing increased net N mineralization rates from 87% to 617% compared to watersheds without grazers, whereas annual burning decreased it by ∼50% compared to unburned prairie. Although grazing speeded up N cycling, it reduced soil respiration by 50% compared to fenced controls, presumably because of reduced root mass. On the other hand, annual burning increased soil respiration, presumably because of increased root biomass. Ultimately, differences in the quantity and quality of roots provide feedback to affect C and N cycling and help to maintain and even promote the fundamental differences in N cycling between burning and grazing in tallgrass prairie.

Two-stage autoignition and edge flames in a high pressure turbulent jet

DOE PAGES

Krisman, Alex; Hawkes, Evatt R.; Chen, Jacqueline H.

2017-07-04

A three-dimensional direct numerical simulation is conducted for a temporally evolving planar jet of n-heptane at a pressure of 40 atmospheres and in a coflow of air at 1100 K. At these conditions, n-heptane exhibits a two-stage ignition due to low- and high-temperature chemistry, which is reproduced by the global chemical model used in this study. The results show that ignition occurs in several overlapping stages and multiple modes of combustion are present. Low-temperature chemistry precedes the formation of multiple spatially localised high-temperature chemistry autoignition events, referred to as ‘kernels’. These kernels form within the shear layer and core ofmore » the jet at compositions with short homogeneous ignition delay times and in locations experiencing low scalar dissipation rates. An analysis of the kernel histories shows that the ignition delay time is correlated with the mixing rate history and that the ignition kernels tend to form in vortically dominated regions of the domain, as corroborated by an analysis of the topology of the velocity gradient tensor. Once ignited, the kernels grow rapidly and establish edge flames where they envelop the stoichiometric isosurface. A combination of kernel formation (autoignition) and the growth of existing burning surface (via edge-flame propagation) contributes to the overall ignition process. In conclusion, an analysis of propagation speeds evaluated on the burning surface suggests that although the edge-flame speed is promoted by the autoignitive conditions due to an increase in the local laminar flame speed, edge-flame propagation of existing burning surfaces (triggered initially by isolated autoignition kernels) is the dominant ignition mode in the present configuration.« less

ACOUSTIC SIGNATURES OF THE HELIUM CORE FLASH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bildsten, Lars; Paxton, Bill; Moore, Kevin

2012-01-15

All evolved stars with masses M {approx}< 2 M{sub Sun} undergo an initiating off-center helium core flash in their M{sub c} Almost-Equal-To 0.48 M{sub Sun} He core as they ascend the red giant branch (RGB). This off-center flash is the first of a few successive helium shell subflashes that remove the core electron degeneracy over 2 Myr, converting the object into a He-burning star. Though characterized by Thomas over 40 years ago, this core flash phase has yet to be observationally probed. Using the Modules for Experiments in Stellar Astrophysics (MESA) code, we show that red giant asteroseismology enabled bymore » space-based photometry (i.e., Kepler and CoRoT) can probe these stars during the flash. The rapid ({approx}< 10{sup 5} yr) contraction of the red giant envelope after the initiating flash dramatically improves the coupling of the p-modes to the core g-modes, making the detection of l = 1 mixed modes possible for these 2 Myr. This duration implies that 1 in 35 stars near the red clump in the H-R diagram will be in their core flash phase. During this time, the star has a g-mode period spacing of {Delta}P{sub g} Almost-Equal-To 70-100 s, lower than the {Delta}P{sub g} Almost-Equal-To 250 s of He-burning stars in the red clump, but higher than the RGB stars at the same luminosity. This places them in an underpopulated part of the large frequency spacing ({Delta}{nu}) versus {Delta}P{sub g} diagram that should ease their identification among the thousands of observed red giants.« less

Mass loss in M67 giants - Evidence from isochrone fitting

NASA Technical Reports Server (NTRS)

Tripicco, Michael J.; Dorman, Ben; Bell, R. A.

1993-01-01

A comparison between the color-magnitude diagram of M67 and a new set of theoretical evolutionary models which include all phases from the unevolved main-sequence through core-helium burning and onto the AGB is presented. The present 5-Gyr solar abundance isochrone is found to yield an excellent fit to the whole of the M67 color-magnitude diagram. A differential technique that compares the gap in color between clump giants and normal red giants, on one hand, with the temperature gap between core He-burning tracks and first-ascent RGB tracks, on the other, strongly indicates that the clump giants in M67 have masses of 0.70 solar mass or less. The extremely large amount of mass loss that is deduced is well in excess of that found for globular cluster stars. Possible resolutions of this problem are that degree of mass loss increases with total stellar mass, or with metallicity.

Reducing Uncertainties in the Production of the Gamma-emitting Nuclei 26Al, 44Ti, and 60Fe in Core-collapse Supernovae by Using Effective Helium Burning Rates

NASA Astrophysics Data System (ADS)

Austin, Sam M.; West, Christopher; Heger, Alexander

2017-04-01

We have used effective reaction rates (ERRs) for the helium burning reactions to predict the yield of the gamma-emitting nuclei 26Al, 44Ti, and 60Fe in core-collapse supernovae (SNe). The variations in the predicted yields for values of the reaction rates allowed by the ERR are much smaller than obtained previously, and smaller than other uncertainties. A “filter” for SN nucleosynthesis yields based on pre-SN structure was used to estimate the effect of failed SNe on the initial mass function averaged yields; this substantially reduced the yields of all these isotopes, but the predicted yield ratio 60Fe/26Al was little affected. The robustness of this ratio is promising for comparison with data, but it is larger than observed in nature; possible causes for this discrepancy are discussed.

A review of the peri-operative management of paediatric burns: Identifying adverse events.

PubMed

Rode, H; Brink, C; Bester, K; Coleman, M P; Baisey, T; Martinez, R

2016-11-02

Burn injuries are common in poverty-stricken countries. The majority of patients with large and complex burns are referred to burn centres. Of the children who qualify for admission, according to burn admission criteria, about half require some kind of surgical procedure to obtain skin cover. These range from massive full-thickness fire burns to skin grafts for small, residual unhealed wounds. Burn anaesthetic procedures are of the most difficult to perform and are known for high complication rates. Reasons include peri-operative sepsis, bleeding, issues around thermoregulation, the hypermetabolic state, nutritional and electrolyte issues, inhalation injuries and the amount of movement during procedures to wash patients, change drapes and access different anatomical sites. The appropriate execution of surgery is therefore of the utmost importance for both minor and major procedures. To review the peri-operative management and standard of surgical care of burnt children. This was a retrospective review and analysis of standard peri-operative care of burnt children at Red Cross War Memorial Children's Hospital, Cape Town, South Africa. A total of 558 children were operated on and supervised by the first author. Factors that could adversely affect surgical and anaesthetic outcomes were identified. There were 257 males and 301 females in this study, with an average age of 50.1 months and average weight of 19.5 kg. The total body surface area involved was 1 - 80%, with an average of 23.5%. Inhalational injury was present in 11.3%, pneumonia in 13.1%, wound sepsis in 20.8%, and septicaemia in 9.7%, and organ dysfunction in more than one organ was seen in 6.1%. The average theatre temperature during surgery was 30.0°C. Core temperatures recorded at the start, halfway through and at completion of surgery were 36.9°C, 36.8°C and 36.5°C, respectively. The average preoperative and postoperative haemoglobin levels were 11.28 g/dL and 9.64 g/dL, respectively. Blood loss was reduced by the use of clysis from 1.5 mL/kg/% burn to 1.4 mL/kg/% burn. Adverse intraoperative events were seen in 17.6% of children. Burn surgery is a high-risk procedure and comorbidities are common. Anaesthesia and surgery must be well planned and executed with special reference to temperature control, rapid blood loss, preceding respiratory illnesses and measures to reduce blood loss.

LANDSAT digital analysis of the initial recovery of the Kokolik River tundra fire area, Alaska

NASA Technical Reports Server (NTRS)

Hall, D. K.; Ormsby, J. P.; Johnson, L.; Brown, J. (Principal Investigator)

1979-01-01

The author has identified the following significant results. Considerable regrowth of vegetation was observed between August 1977 and August 1978, both in the field and through analysis of LANDSAT near infrared digital data. The spectral reflectances in the burned areas were found to increase with the age of the burn in a one year period due to vegetation regrowth. Regrowth was particularly evident in the lightly burned portions of the burned area. Image analysis techniques using the AOIPS system permitted delineation of burn severity categories. The conditions and type of ground cover prior to the fire influenced the severity of burning, as did the direction of the winds while the burning was in progress as determined from field and LANDSAT observations. More severe burning was induced by winds blowing in the northeastern and southeastern portions of the burned area.

Local Burn-Up Effects in the NBSR Fuel Element

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown N. R.; Hanson A.; Diamond, D.

2013-01-31

This study addresses the over-prediction of local power when the burn-up distribution in each half-element of the NBSR is assumed to be uniform. A single-element model was utilized to quantify the impact of axial and plate-wise burn-up on the power distribution within the NBSR fuel elements for both high-enriched uranium (HEU) and low-enriched uranium (LEU) fuel. To validate this approach, key parameters in the single-element model were compared to parameters from an equilibrium core model, including neutron energy spectrum, power distribution, and integral U-235 vector. The power distribution changes significantly when incorporating local burn-up effects and has lower power peakingmore » relative to the uniform burn-up case. In the uniform burn-up case, the axial relative power peaking is over-predicted by as much as 59% in the HEU single-element and 46% in the LEU single-element with uniform burn-up. In the uniform burn-up case, the plate-wise power peaking is over-predicted by as much as 23% in the HEU single-element and 18% in the LEU single-element. The degree of over-prediction increases as a function of burn-up cycle, with the greatest over-prediction at the end of Cycle 8. The thermal flux peak is always in the mid-plane gap; this causes the local cumulative burn-up near the mid-plane gap to be significantly higher than the fuel element average. Uniform burn-up distribution throughout a half-element also causes a bias in fuel element reactivity worth, due primarily to the neutronic importance of the fissile inventory in the mid-plane gap region.« less

Simulation of Fast Neutronics in an Accelerator-Driven Sub-Critical Core

NASA Astrophysics Data System (ADS)

Gwyn Rosaire, C.; Sattarov, Akhdiyor; McIntyre, Peter; Tsvetkov, Pavel

2011-10-01

Accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a technology for green nuclear power. ADSMS burns its fertile fuel to completion, it cannot melt down, and it destroys long-lived minor actinides. The ADSMS core consists of a vessel filled with a molten salt eutectic of UCl3 and NaCl. The fast neutronics of ADSMS makes possible two unique benefits: isobreeding, a steady-state equilibrium in which ^238U is bred to ^239Pu and the ^239Pu fissions, and destruction of minor actinides, in which fission of the intermediary nuclides dominates of breeding. Results of simulations of the fast neutronics in the ADSMS core will be presented.

Fuel Fraction Analysis of 500 MWth Gas Cooled Fast Reactor with Nitride (UN-PuN) Fuel without Refueling

NASA Astrophysics Data System (ADS)

Dewi Syarifah, Ratna; Su'ud, Zaki; Basar, Khairul; Irwanto, Dwi

2017-01-01

Nuclear Power Plant (NPP) is one of candidates which can support electricity demand in the world. The Generation IV NPP has fourth main objective, i.e. sustainability, economics competitiveness, safety and reliability, and proliferation and physical protection. One of Gen-IV reactor type is Gas Cooled Fast Reactor (GFR). In this study, the analysis of fuel fraction in small GFR with nitride fuel has been done. The calculation was performed by SRAC code, both Pij and CITATION calculation. SRAC2002 system is a code system applicable to analyze the neutronics of variety reactor type. And for the data library used JENDL-3.2. The step of SRAC calculation is fuel pin calculated by Pij calculation until the data homogenized, after it homogenized we calculate core reactor. The variation of fuel fraction is 40% up to 65%. The optimum design of 500MWth GFR without refueling with 10 years burn up time reach when radius F1:F2:F3 = 50cm:30cm:30cm and height F1:F2:F3 = 50cm:40cm:30cm, variation percentage Plutonium in F1:F2:F3 = 7%:10%:13%. The optimum fuel fraction is 41% with addition 2% Plutonium weapon grade mix in the fuel. The excess reactivity value in this case 1.848% and the k-eff value is 1.01883. The high burn up reached when the fuel fraction is low. In this study 41% fuel fraction produce faster fissile fuel, so it has highest burn-up level than the other fuel fraction.

Cost analysis of acute burn patients treated in a burn centre: the Gulhane experience

PubMed Central

Sahin, I.; Ozturk, S.; Alhan, D.; Açikel, C.; Isik, S.

2011-01-01

Summary Even if calculating the exact cost of burn treatment is a very hard task, the study of cost analysis provides financial perspective. We performed a cost analysis study in our burn centre to respond to questions about total patient treatment cost and the length of hospital stay. We reviewed all patients admitted to the Gulhane Military Medical Academy Burn Centre in Ankara, Turkey, between March 2005 and August 2008. Forty-three patients with major burns were identified on the basis of the study criteria. The data regarding total treatment cost and the length of hospital stay for each type of burn (flame, scald, electric) were collected at the end of the study. The average total body surface area burned was 36 ± 7%.. The average duration of hospital stay was 73 ± 33 days. Patients with electrical burns stayed longer in hospital than patients with other types of burn injuries. Each one per cent of burn corresponded to a mean hospital stay of two days. The overall mean total cost was $US 15,250. The mean total cost of electrical burns was the highest, with $US 22,501 ± 24,039. Even if the costs associated with burn injury are higher than some other well-known health-related problems, they have not been much studied. Reports have produced different results, but it should be kept in mind that although the results of cost analysis studies may vary they must be performed in all newly established burn centres in order to form a financial overview. PMID:21991233

Orbital Decay in Binaries with Evolved Stars

NASA Astrophysics Data System (ADS)

Sun, Meng; Arras, Phil; Weinberg, Nevin N.; Troup, Nicholas; Majewski, Steven R.

2018-01-01

Two mechanisms are often invoked to explain tidal friction in binary systems. The ``dynamical tide” is the resonant excitation of internal gravity waves by the tide, and their subsequent damping by nonlinear fluid processes or thermal diffusion. The ``equilibrium tide” refers to non-resonant excitation of fluid motion in the star’s convection zone, with damping by interaction with the turbulent eddies. There have been numerous studies of these processes in main sequence stars, but less so on the subgiant and red giant branches. Motivated by the newly discovered close binary systems in the Apache Point Observatory Galactic Evolution Experiment (APOGEE-1), we have performed calculations of both the dynamical and equilibrium tide processes for stars over a range of mass as the star’s cease core hydrogen burning and evolve to shell burning. Even for stars which had a radiative core on the main sequence, the dynamical tide may have very large amplitude in the newly radiative core in post-main sequence, giving rise to wave breaking. The resulting large dynamical tide dissipation rate is compared to the equilibrium tide, and the range of secondary masses and orbital periods over which rapid orbital decay may occur will be discussed, as well as applications to close APOGEE binaries.

Radioactivity of spent TRIGA fuel

NASA Astrophysics Data System (ADS)

Usang, M. D.; Nabil, A. R. A.; Alfred, S. L.; Hamzah, N. S.; Abi, M. J. B.; Rawi, M. Z. M.; Abu, M. P.

2015-04-01

Some of the oldest TRIGA fuel in the Malaysian Reaktor TRIGA PUSPATI (RTP) is approaching the limit of its end of life with burn-up of around 20%. Hence it is prudent for us to start planning on the replacement of the fuel in the reactor and other derivative activities associated with it. In this regard, we need to understand all of the risk associated with such operation and one of them is to predict the radioactivity of the fuel, so as to estimate the safety of our working conditions. The radioactivity of several fuels are measured and compared with simulation results to confirm the burnup levels of the selected fuels. The radioactivity measurement are conducted inside the water tank to reduce the risk of exposure and in this case the detector wrapped in plastics are lowered under water. In nuclear power plant, the general practice was to continuously burn the fuel. In research reactor, most operations are based on the immediate needs of the reactor and our RTP for example operate periodically. By integrating the burnup contribution for each core configuration, we simplify the simulation of burn up for each core configuration. Our results for two (2) fuel however indicates that the dose from simulation underestimate the actual dose from our measurements. Several postulates are investigated but the underlying reason remain inconclusive.

Thorium Fuel Options for Sustained Transuranic Burning in Pressurized Water Reactors - 12381

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, Fariz Abdul; Lee, John C.; Franceschini, Fausto

2012-07-01

As described in companion papers, Westinghouse is proposing the adoption of a thorium-based fuel cycle to burn the transuranics (TRU) contained in the current Used Nuclear Fuel (UNF) and transition towards a less radio-toxic high level waste. A combination of both light water reactors (LWR) and fast reactors (FR) is envisaged for the task, with the emphasis initially posed on their TRU burning capability and eventually to their self-sufficiency. Given the many technical challenges and development times related to the deployment of TRU burners fast reactors, an interim solution making best use of the current resources to initiate burning themore » legacy TRU inventory while developing and testing some technologies of later use is desirable. In this perspective, a portion of the LWR fleet can be used to start burning the legacy TRUs using Th-based fuels compatible with the current plants and operational features. This analysis focuses on a typical 4-loop PWR, with 17x17 fuel assembly design and TRUs (or Pu) admixed with Th (similar to U-MOX fuel, but with Th instead of U). Global calculations of the core were represented with unit assembly simulations using the Linear Reactivity Model (LRM). Several assembly configurations have been developed to offer two options that can be attractive during the TRU transmutation campaign: maximization of the TRU transmutation rate and capability for TRU multi-recycling, to extend the option of TRU recycling in LWR until the FR is available. Homogeneous as well as heterogeneous assembly configurations have been developed with various recycling schemes (Pu recycle, TRU recycle, TRU and in-bred U recycle etc.). Oxide as well as nitride fuels have been examined. This enabled an assessment of the potential for burning and multi-recycling TRU in a Th-based fuel PWR to compare against other more typical alternatives (U-MOX and variations thereof). Results will be shown indicating that Th-based PWR fuel is a promising option to multi-recycle and burn TRU in a thermal spectrum, while satisfying top-level operational and safety constraints. Various assembly designs have been proposed to assess the TRU burning potential of Th-based fuel in PWRs. In addition to typical homogeneous loading patterns, heterogeneous configurations exploiting the breeding potential of thorium to enable multiple cycles of TRU irradiation and burning have been devised. The homogeneous assembly design, with all pins featuring TRU in Th, has the benefit of a simple loading pattern and the highest rate of TRU transmutation, but it can be used only for a few cycles due to the rapid rise in the TRU content of the recycled fuel, which challenges reactivity control, safety coefficients and fuel handling. Due to its simple loading pattern, such assembly design can be used as the first step of Th implementation, achieving up to 3 times larger TRU transmutation rate than conventional U-MOX, assuming same fraction of MOX assemblies in the core. As the next step in thorium implementation, heterogeneous assemblies featuring a mixed array of Th-U and Th-U-TRU pins, where the U is in-bred from Th, have been proposed. These designs have the potential to enable burning an external supply of TRU through multiple cycles of irradiation, recovery (via reprocessing) and recycling of the residual actinides at the end of each irradiation cycle. This is achieved thanks to a larger breeding of U from Th in the heterogeneous assemblies, which reduces the TRU supply and thus mitigates the increase in the TRU core inventory for the multi-recycled fuel. While on an individual cycle basis the amount of TRU burned in the heterogeneous assembly is reduced with respect to the homogeneous design, TRU burning rates higher than single-pass U-MOX fuel can still be achieved, with the additional benefits of a multi-cycle transmutation campaign recycling all TRU isotopes. Nitride fuel, due its higher density and U breeding potential, together with its better thermal properties, ideally suits the objectives and constraints of the heterogeneous assemblies. However, significant technological advancements must be made before nitride fuels can be employed in an LWR: its water resistance needs to be improved and a viable technology to enrich N in N-15 must be devised. Moreover, for the nitride heterogeneous configurations examined in this study, the enhancement in TRU burning performance is achieved not only by replacing oxide with nitride fuel, but also by increasing the fuel rod size. This latter modification, allowed by the high thermal conductivity of nitride fuel, leads however to a very tight lattice, which may challenge reactor coolant pumps and assembly hold-down mechanisms, the former through an increase in core pressure drop and the latter through an increase in assembly lift-off forces. To alleviate these issues, while still achieving the large fuel-to-moderator ratios resulting from using tight lattices, wire wraps could be used in place of grid spacers. For tight lattices, typical grid spacers are hard to manufacture and their replacement with wire wraps is known to allow for a pressure drop reduction by at least 2 times. The studies, while certainly very preliminary, provide a starting point to devise an optimum strategy for TRU transmutation in Th-based PWR fuel. The viability of the scheme proposed depends on the timely phasing in of the associated technologies, with proper lead time and to solve the many challenges. These challenges are certainly substantial, and make the current once-through U-based scheme pursued in the US by far a more practical (and cheaper) option. However, when compared to other transmutation schemes, the proposed one has arguably similar challenges and unknowns with potentially bigger rewards. (authors)« less

Theoretical Developments in Understanding Massive Star Formation

NASA Technical Reports Server (NTRS)

Yorke, Harold W.; Bodenheimer, Peter

2007-01-01

Except under special circumstances massive stars in galactic disks will form through accretion. The gravitational collapse of a molecular cloud core will initially produce one or more low mass quasi-hydrostatic objects of a few Jupiter masses. Through subsequent accretion the masses of these cores grow as they simultaneously evolve toward hydrogen burning central densities and temperatures. We review the evolution of accreting (proto-)stars, including new results calculated with a publicly available stellar evolution code written by the authors.

Black carbon content in a ponderosa pine forest of eastern Oregon with varying seasons and intervals of prescribed burns

NASA Astrophysics Data System (ADS)

Matosziuk, L.; Hatten, J. A.

2016-12-01

Soil carbon represents a significant component of the global carbon cycle. While fire-based disturbance of forest ecosystems acts as a carbon source, the increased temperatures can initiate molecular changes to forest biomass that convert fast cycling organic carbon into more stable forms such as black carbon (BC), a product of incomplete combustion that contains highly-condensed aromatic structures and very low hydrogen and oxygen content. Such forms of carbon can remain in the soil for hundred to thousands of years, effectively creating a long-term carbon sink. The goal of this project is to understand how specific characteristics of prescribed burns, specifically the season of burn and the interval between burns, affect the formation, structure, and retention of these slowly degrading forms of carbon in the soil. Both O-horizon (forest floor) and mineral soil (0-15 cm cores) samples were collected from a season and interval of burn study in Malheur National Forest. The study area is divided into six replicate units, each of which is sub-divided into four treatment areas and a control. Beginning in 1997, each treatment area was subjected to: i) spring burns at five-year intervals, ii) fall burns at five-year intervals, iii) spring burns at 15-year intervals, or iv) fall burns at 15-year intervals. The bulk density, pH, and C/N content of each soil were measured to assess the effect of the burn treatments on the soil. Additionally, the amount and molecular structure of BC in each sample was quantified using the distribution of specific molecular markers (benzene polycarboxylic acids or BPCAs) that are present in the soil following acid digestion.

Advanced Burner Reactor with Breed-and-Burn Thorium Blankets for Improved Economics and Resource Utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenspan, Ehud

2015-11-04

This study assesses the feasibility of designing Seed and Blanket (S&B) Sodium-cooled Fast Reactor (SFR) to generate a significant fraction of the core power from radial thorium fueled blankets that operate on the Breed-and-Burn (B&B) mode without exceeding the radiation damage constraint of presently verified cladding materials. The S&B core is designed to maximize the fraction of neutrons that radially leak from the seed (or “driver”) into the subcritical blanket and reduce neutron loss via axial leakage. The blanket in the S&B core makes beneficial use of the leaking neutrons for improved economics and resource utilization. A specific objective ofmore » this study is to maximize the fraction of core power that can be generated by the blanket without violating the thermal hydraulic and material constraints. Since the blanket fuel requires no reprocessing along with remote fuel fabrication, a larger fraction of power from the blanket will result in a smaller fuel recycling capacity and lower fuel cycle cost per unit of electricity generated. A unique synergism is found between a low conversion ratio (CR) seed and a B&B blanket fueled by thorium. Among several benefits, this synergism enables the very low leakage S&B cores to have small positive coolant voiding reactivity coefficient and large enough negative Doppler coefficient even when using inert matrix fuel for the seed. The benefits of this synergism are maximized when using an annular seed surrounded by an inner and outer thorium blankets. Among the high-performance S&B cores designed to benefit from this unique synergism are: (1) the ultra-long cycle core that features a cycle length of ~7 years; (2) the high-transmutation rate core where the seed fuel features a TRU CR of 0.0. Its TRU transmutation rate is comparable to that of the reference Advanced Burner Reactor (ABR) with CR of 0.5 and the thorium blanket can generate close to 60% of the core power; but requires only one sixth of the reprocessing and fabrication capacity per unit of core power. Nevertheless, these high-performance cores were designed to set upper bounds on the S&B core performance by using larger height and pressure drop than those of typical SFR design. A study was subsequently undertaken to quantify the tradeoff between S&B core design variables and the core performance. This study concludes that a viable S&B core can be designed without significant deviation from SFR core design practices. For example, the S&B core with 120cm active height will be comparable in volume, HM mass and specific power with the S-PRISM core and could fit within the S-PRISM reactor vessel. 43% of this core power will be generated by the once-through thorium blanket; the required capacity for reprocessing and remote fuel fabrication per unit of electricity generated will be approximately one fifth of that for a comparable ABR. The sodium void worth of this 120cm tall S&B core is significantly less positive than that of the reference ABR and the Doppler coefficient is only slightly smaller even though the seed uses a fertile-free fuel. The seed in the high transmutation core requires inert matrix fuel (TRU-40Zr) that has been successfully irradiated by the Fuel Cycle Research & Development program. An additional sensitivity analysis was later conducted to remove the bias introduced by the discrepancy between radiation damage constraints -- 200 DPA applied for S&B cores and fast fluence of 4x1023 n(>0.1MeV)/cm2 applied for ABR core design. Although the performance characteristics of the S&B cores are sensitive to the radiation damage constraint applied, the S&B cores offer very significant performance improvements relative to the conventional ABR core design when using identical constraint.« less

Core-shelled mesoporous CoFe2O4-SiO2 material with good adsorption and high-temperature magnetic recycling capabilities

NASA Astrophysics Data System (ADS)

Li, Zhi'ang; Wang, Jianlin; Liu, Min; Chen, Tong; Chen, Jifang; Ge, Wen; Fu, Zhengping; Peng, Ranran; Zhai, Xiaofang; Lu, Yalin

2018-04-01

Residues of organic dye in industrial effluents cause severe water system pollution. Although several methods, such as biodegradation and activated carbon adsorption, are available for treating these effluents before their discharge into waterbodies, secondary pollution by adsorbents and degrading products remains an issue. Therefore, new materials should be identified to solve this problem. In this work, CoFe2O4-SiO2 core-shell structures were synthesized using an improved Stöber method by coating mesoporous silica onto CoFe2O4 nanoparticles. The specific surface areas of the synthesized particles range from 30 m2/g to 150 m2/g and vary according to the dosage amount of tetraethoxysilane. Such core-shelled nanoparticles have the following advantages for treating industrial effluents mixed with dye: good adsorption capability, above-room-temperature magnetic recycling capability, and heat-enduring stability. Through adsorption of methylene blue, a typical dyeing material, the core-shell-structured particles show a good adsorption capability of approximately 33 mg/L. The particles are easily and completely collected by magnets, which is possible due to the magnetic property of core CoFe2O4. Heat treatment can burn out the adsorbed dyes and good adsorption performance is sustained even after several heat-treating loops. This property overcomes the common problem of particles with Fe3O4 as a core, by which Fe3O4 is oxidized to nonmagnetic α-Fe2O3 at the burning temperature. We also designed a miniature of effluent-treating pipeline, which demonstrates the potential of the application.

Measuring forest floor evaporation from interception in prescribed burned forests in Southern Italy.

NASA Astrophysics Data System (ADS)

Giuditta, Elisabetta; Coenders-Gerrits, Miriam; Bogaard, Thom; Wenninger, Jochen; Greco, Roberto; Ialongo, Gianluca; Esposito, Assunta; Rutigliano, Flora Angela

2016-04-01

Wildfires are one of the major environmental issue in the Mediterranean area. Prescribed burning (PB) is increasingly used in Europe as a practice to reduce fire risk, through dead fine fuel reduction. Several studies have focused on fire effects on vegetation and soil microbial community, but very few on ecosystem processes involved in water cycle. This study aims to estimate interception by the litter and fermentation layer and the successive evaporation flux in laboratory conditions, using a water balance and 2H and 18O isotopes mass balance calculation, in order to assess PB effects on the hydrology and ecosystem in pine plantations. PB was carried out in spring 2014 in three pine plantations of Southern Italy, dominated by Pinus halepensis (Cilento, Vallo di Diano e Alburni National Park, CVDANP), P. pinaster (Vesuvio National Park, VNP) and P. pinea (Castel Volturno Nature Reserve, CVNR). A dataset concerning the effects of PB on vegetation structure, floristic composition, microbial biomass and activity in the fermentation layer and 5-cm of soil beneath is available for the same stands. In each plantation, two cores of litter and fermentation layer were sampled in a burned area and in a near unburned area (control), respectively, with a collector to extract an "undisturbed" core. Then, each core was transferred in a lysimeter installed in the Water Lab of Delft University of Technology. In total, three lysimeters were set up and each experiment was carried out in duplicate. The laboratory had constant temperature, and both temperature and relative humidity were recorded every 15 minutes. To simulate rainfall, ~1 litre of tap water was sprinkled uniformly on the lysimeter with a plant spray (equivalent to 32 mm of rain). The precipitation was sprinkled every 3 days for a period of two months. Soil moisture and temperature were measured during the experiment every 15 minutes in the top and bottom of the litter and fermentation layer. Interception water was collected for isotope analysis from every layer with Rhizon soil moisture samplers by applying a vacuum with 5 ml syringes. Samples were collected two times per day (in the morning and in the evening) and at two different depths for each layer (~4 cm and ~7 cm in litter layer and ~10 and ~15 cm in fermentation layer) until 2 days after rain simulation. Water samples were analysed with laser spectrometry using the liquid water isotope analyser (LGR-LWIA). The influence of different litter layers and PB on interception and litter layer evaporation was assessed. Then, the evaporation flux measured using the lysimeter was compared with the calculated evaporation flux using the isotopes mass balance. Generally, the preliminary results indicate a slight increase in evaporation flux in burned areas compared to the controls, in P. pinea and P. pinaster stands. By contrast, in P. halepensis stand, a significant decrease in evaporation flux was detected in prescribed burned plot. The isotope mass balance method to measure litter evaporation is promising and could be used in future, in-situ, measurements of evaporation from the litter layer.

Burn care delivery in a sub-saharan african unit: A cost analysis study.

PubMed

Gallaher, Jared R; Mjuweni, Stephen; Cairns, Bruce A; Charles, Anthony G

2015-07-01

There are significant resource challenges to burn surgical care delivery in low and middle-income countries at baseline and only a few burn cost analysis studies from sub-Saharan Africa have been performed. This is a retrospective database analysis of prospectively collected data from all patients recorded in the burn registry between June 2011 and August 2014 located at the Kamuzu Central Hospital Burn Unit in Lilongwe, Malawi. We utilized activity-based costing, a bottom-up cost analysis methodology with cost allocation that allows determination of unit cost or cost per service. 905 patients were admitted to the burn unit during the study period. The calculated total monthly burn expenditure for all cost centers was $11,622.66. Per day, the total unit cost was $387.42 with a mean daily per-patient cost of $24.26 (SD ± $6.44). Consequently, the mean cost per in-patient admission was $559.85 (SD ± $736.17). The mean daily cost per 1% total burn surface per patient at our center is $2.65 (SD ± $3.01). This burn care cost analysis study helps quantify the relative contribution of differing cost centers that comprise burn care delivery and hospital costs in a sub-Saharan African setting. Accurate and relevant cost information on hospital services at the patient level is therefore fundamental for policy makers, payers, and hospitals. Our study has demonstrated that comprehensive burn care is possible at a cost much lower than found in other burn centers in low or middle-income countries and can be sustained with moderate funding. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

Soil respiration and root biomass responses to burning in calabrian pine (Pinus brutia) stands in Edirne, Turkey.

PubMed

Tufekcioglu, Aydin; Kucuk, Mehmet; Bilmis, Tuncay; Altun, Lokman; Yilmaz, Murat

2010-01-01

In this study soil properties and root biomass responses to prescribed fire were investigated in 25-30 year-old calabrian pine (Pinus brutia Ten.) stands in Edirne, Turkey. The stands were established by planting and were subjected to prescribed burning in July 2005. Soil respiration rates were determined every two months using the soda-lime method over a two-year period. Fine (> or = 2 mm diameter) and small root (> 2-5 mm diameter) biomass were sampled approximately bimonthly using the sequential coring method. Soil respiration rates in burned sites were significantly higher than in control sites during the summer season but there was no significant difference in the other seasons. Soil respiration rates were correlated significantly with soil moisture and soil temperature. Fine and small root biomass were significantly lower in burned sites than in control sites. Mean fine root biomass values were 3204 kg ha(-1) for burned and 3772 kg ha(-1) for control sites. Annual soil CO2 releases totaled 515 g Cm(-2) for burned and 418 g C m(-2) for control sites. Our results indicate that, depending on site conditions, fire could be used successfully as a tool in the management of calabrian pine stands in the study area.

Mechanisms of motor vehicle crashes related to burns--an analysis of the German In depth Accident Study (GIDAS) database.

PubMed

Brand, S; Otte, D; Stübig, T; Petri, M; Ettinger, M; Mueller, C W; Krettek, C; Haasper, C; Probst, C

2013-12-01

Patients of motor vehicle crashes (MVCs) suffering burns are challenging for the rescue team and the admitting hospital. These patients often face worse outcomes than crash patients with trauma only. Our analysis of the German In-depth Accident Study (GIDAS) database researches the detailed crash mechanisms to identify potential prevention measures. We analyzed the 2011 GIDAS database comprising 14,072 MVC patients and compared individuals with (Burns) and without (NoBurns) burns. Only complete data sets were included. Patients with burns obviously resulting of air bag deployment only were not included in the Burns group. Data acquisition by an on call team of medical and technical researchers starts at the crash scene immediately after the crash and comprises technical data as well as medical information until discharge from the hospital. Statistical analysis was done by Mann-Whitney-U-test. Level of significance was p < 0.05. 14,072 MVC patients with complete data sets were included in the analysis. 99 individuals suffered burns (0.7%; group "Burns"). Demographic data and injury severity showed no statistical significant difference between the two groups of Burns and NoBurns. Injury severity was measured using the Injury Severity Score (ISS). Direct frontal impact (Burns: 48.5% vs. NoBurns: 33%; p < 0.05) and high-energy impacts as represented by delta-v (m/s) (Burns: 33.5 ± 21.4 vs. NoBurns: 25.2 ± 15.9; p < 0.05) were significantly different between groups as was mortality (Burns: 12.5% vs. NoBurns: 2.1%; p < 0.05). Type of patients' motor vehicles and type of crash opponent showed no differences. Our results show, that frontal and high-energy impacts are associated with a frequency of burns. This may serve automobile construction companies to improve the burn safety to prevent flames spreading from the motor compartment to the passenger compartment. Communities may impose speed limits in local crash hot spots. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Organic molecules in the polar ice: from chemical analysis to environmental proxies

NASA Astrophysics Data System (ADS)

Barbante, Carlo; Zennaro, Piero; Giorio, Chiara; Kehrwald, Natalie; Benton, Alisa K.; Wolff, Eric W.; Kalberer, Markus; Kirchgeorg, Torben; Zangrando, Roberta; Barbaro, Elena; Gambaro, Andrea

2015-04-01

The molecular and isotopic compositions of organic matter buried in ice contains information that helps reconstruct past environmental conditions, evaluate histories of climate change, and assess impacts of humans on ecosystems. In recent years novel analytical techniques were developed to quantify molecular compounds in ice cores. As an example, biomass burning markers, including monosaccharide anhydrides, lightweight carboxylic acids, lignin and resin pyrolysis products, black carbon, and charcoal records help in reconstructing past fire activity across seasonal to millennial time scales. Terrestrial biomarkers, such as plant waxes (e.g. long-chain n-alkanes) are also a promising paleo vegetation proxy in ice core studies. Polycyclic aromatic hydrocarbons are ubiquitous pollutants recently detected in ice cores. These hydrocarbons primarily originate from incomplete combustion of organic matter and fossil fuels (e.g. diesel engines, domestic heating, industrial combustion) and therefore can be tracers of past combustion activities. In order to be suitable for paloeclimate purposes, organic molecular markers detected in ice cores should include the following important features. Markers have to be stable under oxidizing atmospheric conditions, and ideally should not react with hydroxyl radicals, during their transport to polar regions. Organic markers must be released in large amounts in order to be detected at remote distances from the sources. Proxies must be specific, in order to differentiate them from other markers with multiple sources. The extraction of glaciochemical information from ice cores is challenging due to the low concentrations of some impurities, thereby demanding rigorous control of external contamination sources and sensitive analytical techniques. Here, we review the analysis and use of organic molecules in ice as proxies of important environmental and climatic processes.

NO 2 oxidation reactivity and burning mode of diesel particulates

DOE PAGES

Strzelec, Andrea; Vander Wal, Randy L.; Thompson, Thomas N.; ...

2016-03-24

The NO 2 oxidation kinetics and burning mode for diesel particulate from light-duty and medium-duty engines fueled with either ultra low sulfur diesel or soy methyl ester biodiesel blends have been investigated and are shown to be significantly different from oxidation by O 2. Oxidation kinetics were measured using a flow-through packed bed microreactor for temperature programmed reactions and isothermal differential pulsed oxidation reactions. The burning mode was evaluated using the same reactor system for flowing BET specific surface area measurements and HR-TEM with fringe analysis to evaluate the nanostructure of the nascent and partially oxidized particulates. The low activationmore » energy measured, specific surface area progression with extent of oxidation, HR-TEM images and difference plots of fringe length and tortuosity paint a consistent picture of higher reactivity for NO 2, which reacts indiscriminately immediately upon contact with the surface, leading to the Zone I or shrinking core type oxidation. In comparison, O 2 oxidation is shown to have relatively lower reactivity, preferentially attacking highly curved lamella, which are more reactive due to bond strain, and short lamella, which have a higher proportion of more reactive edge sites. Furthermore, this preferential oxidation leads to Zone II type oxidation, where solid phase diffusion of oxygen via pores contributes significantly to slowing the overall oxidation rate, by comparison.« less

Comparing the Global Charcoal Database with Burned Area Trends from an Offline Fire Model Driven by the NCAR Last Millennium Ensemble

NASA Astrophysics Data System (ADS)

Schaefer, A.; Magi, B. I.; Marlon, J. R.; Bartlein, P. J.

2017-12-01

This study uses an offline fire model driven by output from the NCAR Community Earth System Model Last Millennium Ensemble (LME) to evaluate how climate, ecological, and human factors contributed to burned area over the past millennium, and uses the Global Charcoal Database (GCD) record of fire activity as a constraint. The offline fire model is similar to the fire module within the NCAR Community Land Model. The LME experiment includes 13 simulations of the Earth system from 850 CE through 2005 CE, and the fire model simulates burned area using LME climate and vegetation with imposed land use and land cover change. The fire model trends are compared to GCD records of charcoal accumulation rates derived from sediment cores. The comparisons are a way to assess the skill of the fire model, but also set up a methodology to directly test hypotheses of the main drivers of fire patterns over the past millennium. The focus is on regions selected from the GCD with high data density, and that have lake sediment cores that best capture the last millennium. Preliminary results are based on a fire model which excludes burning cropland and pasture land cover types, but this allows some assessment of how climate variability is captured by the fire model. Generally, there is good agreement between modeled burned area trends and fire trends from GCD for many regions of interest, suggesting the strength of climate variability as a control. At the global scale, trends and features are similar from 850 to 1700, which includes the Medieval Climate Anomaly and the Little Ice Age. After 1700, the trends significantly deviate, which may be due to non-cultivated land being converted to cultivated. In key regions of high data density in the GCD such as the Western USA, the trends agree from 850 to 1200 but diverge from 1200 to 1300. From 1300 to 1800, the trends show good agreement again. Implementing processes to include burning cultivated land within the fire model is anticipated to improve the agreement, but also to test the sensitivity of models to different drivers of fire.

The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + Ne + Mg cores

NASA Technical Reports Server (NTRS)

Timmes, F. X.; Woosley, S. E.; Taam, Ronald E.

1994-01-01

We determine the speeds, and many other physical properties, of flame fronts that propagate inward into degenerate and semidegenerate cores of carbon and oxygen (CO) and neon and oxygen (NeOMg) white dwarfs when such flames are bounded on their exterior by a convective region. Combustion in such fronts, per se, is incomplete, with only a small part of the initial mass function burned. A condition of balanced power is set up in the star where the rate of energy emitted as neutrinos from the convective region equals the power available from the unburned fuel that crosses the burning front. The propagation of the burning front itself is in turn limited by the temperature at the base of the convective shell, while cannot greatly exceed the adiabatic value. Solving for consistency between these two conditions gives a unique speed for the flame. Typical values for CO white dwarfs are a few hundredths of a centimeter per second. Flames in NeOMg mixtures are slower. Tables are presented in a form that can easily be implemented in stellar evolution codes and yield the rate at which the convective shell advances into the interior. Combining these velocities with the local equations for stellar structure, we find a minimum density for each gravitational potential below with the local equations for stellar structure, we find a minimum density for each gravitational potential below which the flame cannot propagate, and must die. Although detailed stellar models will have to be constructed to reslove some issues conclusively, our results that a CO white dwarf inginted at its edge will not burn carbon all the way to its center unless the mass of the white dwarf exceeds 0.8 solar mass. On the other hand, it is difficult to ignite carbon burning by compression alone anywhere in a white dwarf whose mass does not exceed 1.0 solar mass. Thus, compressionally ignited shell carbon burning in an accerting CO dwarf almost certainly propagates all the way to the center of the star. Implications for neutron star formation, and Type Ia supernova models, are briefly discussed. These are also applicable to massive stars in the about 10-12 solar mass range which ignite neon burning off center.

Diagnosis of cutaneous thermal burn injuries by multispectral imaging analysis

NASA Technical Reports Server (NTRS)

Anselmo, V. J.; Zawacki, B. E.

1978-01-01

Special photographic or television image analysis is shown to be a potentially useful technique to assist the physician in the early diagnosis of thermal burn injury. A background on the medical and physiological problems of burns is presented. The proposed methodology for burns diagnosis from both the theoretical and clinical points of view is discussed. The television/computer system constructed to accomplish this analysis is described, and the clinical results are discussed.

Analysis of trends in experimental observables: Reconstruction of the implosion dynamics and implications for fusion yield extrapolation for direct-drive cryogenic targets on OMEGA

NASA Astrophysics Data System (ADS)

Bose, A.; Betti, R.; Mangino, D.; Woo, K. M.; Patel, D.; Christopherson, A. R.; Gopalaswamy, V.; Mannion, O. M.; Regan, S. P.; Goncharov, V. N.; Edgell, D. H.; Forrest, C. J.; Frenje, J. A.; Gatu Johnson, M.; Yu Glebov, V.; Igumenshchev, I. V.; Knauer, J. P.; Marshall, F. J.; Radha, P. B.; Shah, R.; Stoeckl, C.; Theobald, W.; Sangster, T. C.; Shvarts, D.; Campbell, E. M.

2018-06-01

This paper describes a technique for identifying trends in performance degradation for inertial confinement fusion implosion experiments. It is based on reconstruction of the implosion core with a combination of low- and mid-mode asymmetries. This technique was applied to an ensemble of hydro-equivalent deuterium-tritium implosions on OMEGA which achieved inferred hot-spot pressures ≈56 ± 7 Gbar [Regan et al., Phys. Rev. Lett. 117, 025001 (2016)]. All the experimental observables pertaining to the core could be reconstructed simultaneously with the same combination of low and mid-modes. This suggests that in addition to low modes, which can cause a degradation of the stagnation pressure, mid-modes are present which reduce the size of the neutron and x-ray producing volume. The systematic analysis shows that asymmetries can cause an overestimation of the total areal density in these implosions. It is also found that an improvement in implosion symmetry resulting from correction of either the systematic mid or low modes would result in an increase in the hot-spot pressure from 56 Gbar to ≈ 80 Gbar and could produce a burning plasma when the implosion core is extrapolated to an equivalent 1.9 MJ symmetric direct illumination [Bose et al., Phys. Rev. E 94, 011201(R) (2016)].

Analysis of trends in experimental observables: Reconstruction of the implosion dynamics and implications for fusion yield extrapolation for direct-drive cryogenic targets on OMEGA

DOE PAGES

Bose, A.; Betti, R.; Mangino, D.; ...

2018-05-29

This paper describes a technique for identifying trends in performance degradation for inertial con finement fusion implosion experiments. It is based on reconstruction of the implosion core with a combination of low- and mid-mode asymmetries. This technique was applied to an ensemble of hydro-equivalent deuterium-tritium implosions on OMEGA that achieved inferred hot-spot pressures ≈56 ± 7 Gbar [S. Regan et al., Phys. Rev. Lett. 117, 025001 (2016)]. All the experimental observables pertaining to the core could be reconstructed simultaneously with the same combination of low and mid modes. This suggests that in addition to low modes, that can cause amore » degradation of the stagnation pressure, mid modes are present that reduce the size of the neutron and x-ray producing volume. The systematic analysis shows that asymmetries can cause an overestimation of the total areal density in these implosions. Finally, it is also found that an improvement in implosion symmetry resulting from correction of either the systematic mid or low modes would result in an increase of the hot-spot pressure from 56 Gbar to ≈ 80 Gbar and could produce a burning plasma when the implosion core is extrapolated to an equivalent 1.9 MJ symmetric direct illumination [A. Bose et al., Phys. Rev. E 94, 011201(R) (2016)].« less

Analysis of trends in experimental observables: Reconstruction of the implosion dynamics and implications for fusion yield extrapolation for direct-drive cryogenic targets on OMEGA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bose, A.; Betti, R.; Mangino, D.

This paper describes a technique for identifying trends in performance degradation for inertial con finement fusion implosion experiments. It is based on reconstruction of the implosion core with a combination of low- and mid-mode asymmetries. This technique was applied to an ensemble of hydro-equivalent deuterium-tritium implosions on OMEGA that achieved inferred hot-spot pressures ≈56 ± 7 Gbar [S. Regan et al., Phys. Rev. Lett. 117, 025001 (2016)]. All the experimental observables pertaining to the core could be reconstructed simultaneously with the same combination of low and mid modes. This suggests that in addition to low modes, that can cause amore » degradation of the stagnation pressure, mid modes are present that reduce the size of the neutron and x-ray producing volume. The systematic analysis shows that asymmetries can cause an overestimation of the total areal density in these implosions. Finally, it is also found that an improvement in implosion symmetry resulting from correction of either the systematic mid or low modes would result in an increase of the hot-spot pressure from 56 Gbar to ≈ 80 Gbar and could produce a burning plasma when the implosion core is extrapolated to an equivalent 1.9 MJ symmetric direct illumination [A. Bose et al., Phys. Rev. E 94, 011201(R) (2016)].« less

High-resolution depositional records of polycyclic aromatic hydrocarbons in the central continental shelf mud of the East China Sea.

PubMed

Guo, Zhigang; Lin, Tian; Zhang, Gan; Yang, Zuosheng; Fang, Ming

2006-09-01

A well-placed 210Pb-dated sediment core extracted from the distal mud in the central continental shelf of the East China Sea is used to reconstruct the high-resolution atmospheric depositional record of polycyclic aromatic hydrocarbons (PAHs), believed to be transported mainly from China in the past 200 years due to the East Asian Monsoon. Total PAHs (TPAHs), based on the 16 USEPA priority PAHs, range from 27 in 1788 to 132 ng g(-1) in 2001. TPAH variation in the core reflects energy usage changes and follows closely the historical economic development in China. PAHs in the core are dominantly pyrogenic in source, i.e., they are mainly from the incomplete combustion of coal and biomass burning. Several individual PAHs suggest that contribution from incomplete petroleum combustion has increased during recent years. Analysis of the 2 + 3 ring and the 5 + 6 ring PAHs and principle component analysis provide more evidence in the change in the energy structure, especially after 1978 when China embarked on the "Reform and Open" Policy, indicating the transformation from an agricultural to an industrial economy of China. The historical profile of PAH distribution in the study area is obviously different from the United States and Europe due to their difference in energy structure and economic development stages.

THE EFFECT OF THE {sup 14}N(p, {gamma}){sup 15}O REACTION ON THE BLUE LOOPS IN INTERMEDIATE-MASS STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halabi, Ghina M.; El Eid, Mounib F.; Champagne, Arthur

2012-12-10

We present stellar evolutionary sequences of stars in the mass range 5-12 M{sub Sun }, having solar-like initial composition. The stellar models are obtained using updated input physics, including recent rates of thermonuclear reactions. We investigate the effects of a modification of the {sup 14}N(p, {gamma}){sup 15}O reaction rate, as suggested by recent evaluations, on the formation and extension of the blue loops encountered during the evolution of the stars in the above mass range. We find that a reduced {sup 14}N(p, {gamma}){sup 15}O rate, as described in the text, has a striking impact on the physical conditions of burningmore » and mixing during shell hydrogen burning when the blue loops are formed. In particular, we find that the efficiency of shell hydrogen burning is crucial for the formation of an extended blue loop. We show that a significantly reduced {sup 14}N(p, {gamma}){sup 15}O rate affects severely the extension of the blue loops and the time spent by the star in the blue part of the Hertzsprung-Russell diagram in the mass range 5-7 M{sub Sun} if the treatment of convection is based on the Schwarzschild criterion only. In this case, envelope overshooting helps to restore well-extended blue loops as supported by the observations of the Cepheid stars. If core overshooting is included during the core hydrogen and core helium burning phases, the loop formation and its properties depend on how this overshooting is treated for a given stellar mass range, as well as on its efficiency.« less

Engineering and Physics Optimization of Breed and Burn Fast Reactor Systems; NUCLEAR ENERGY RESEARCH INITIATIVE (NERI) QUARTERLY PROGRESS REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavel Hejzlar, Peter Yarsky, Mike Driscoll, Dan Wachs, Kevan Weaver, Ken Czerwinski, Mike Pope, James Parry, Theron D. Marshall, Cliff B. Davis, Dustin Crawford, Thomas Hartmann, Pradip Saha; Hejzlar, Pavel; Yarsky, Peter

2005-01-31

This project is organized under four major tasks (each of which has two or more subtasks) with contributions among the three collaborating organizations (MIT, INEEL and ANL-West): Task A: Core Physics and Fuel Cycle; Task B: Core Thermal Hydraulics; Task C: Plant Design; Task D: Fuel Design The lead PI, Michael J. Driscoll, has consolidated and summarized the technical progress submissions provided by the contributing investigators from all sites, under the above principal task headings.

Fossil fuel and biomass burning effect on climate - Heating or cooling?

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.; Fraser, Robert S.; Mahoney, Robert L.

1991-01-01

The basic theory of the effect of pollution on cloud microphysics and its global implications is applied to compare the relative effect of a small increase in the consumption rate of oil, coal, or biomass burning on cooling and heating of the atmosphere. The characteristics of and evidence for the SO2 induced cooling effect are reviewed. This perturbation analysis approach permits linearization, therefore simplifying the analysis and reducing the number of uncertain parameters. For biomass burning the analysis is restricted to burning associated with deforestation. Predictions of the effect of an increase in oil or coal burning show that within the present conditions the cooling effect from oil and coal burning may range from 0.4 to 8 times the heating effect.

The QSE-Reduced Nuclear Reaction Network for Silicon Burning

NASA Astrophysics Data System (ADS)

Hix, W. Raphael; Parete-Koon, Suzanne T.; Freiburghaus, Christian; Thielemann, Friedrich-Karl

2007-09-01

Iron and neighboring nuclei are formed in massive stars shortly before core collapse and during their supernova outbursts, as well as during thermonuclear supernovae. Complete and incomplete silicon burning are responsible for the production of a wide range of nuclei with atomic mass numbers from 28 to 64. Because of the large number of nuclei involved, accurate modeling of silicon burning is computationally expensive. However, examination of the physics of silicon burning has revealed that the nuclear evolution is dominated by large groups of nuclei in mutual equilibrium. We present a new hybrid equilibrium-network scheme which takes advantage of this quasi-equilibrium in order to reduce the number of independent variables calculated. This allows accurate prediction of the nuclear abundance evolution, deleptonization, and energy generation at a greatly reduced computational cost when compared to a conventional nuclear reaction network. During silicon burning, the resultant QSE-reduced network is approximately an order of magnitude faster than the full network it replaces and requires the tracking of less than a third as many abundance variables, without significant loss of accuracy. These reductions in computational cost and the number of species evolved make QSE-reduced networks well suited for inclusion within hydrodynamic simulations, particularly in multidimensional applications.

Measurements for the BETC in-situ combustion experiment. [Post test surveys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wayland, J.R.; Bartel, L.C.

The Bartlesville Energy Technology Center (BETC) in situ combustion pilot project near Bartlette, Kansas, was studied using controlled source audio-magnetotelluric (CSAMT) mapping, thermal gravimetric analysis (TGA), conventional geophysical logging and modeling of the fireflood. Measurements of formation resistivity changes induced by in situ combustion indicate that CSAMT resistivity maps should show an increase in apparent resistivity. The substantial decrease of apparent resistivity measured within the five spot pattern indicated a complex sequence of events. Using the results from the CSAMT surveys the fire front was located and posttest core samples were obtained. The posttest core samples were examined using TGAmore » techniques, and using information from combustion tube runs as standards, the location of the fire front in the core samples from the posttest holes was inferred. Models of the reservoir in situ combustion process were developed to help analyze the field results. The combustion kinematics, when used in conjunction with CSAMT and TGA techniques, indicated that considerable bypass of injected air occurred with an influx of brine into previously burned zones. This experiment offered an opportunity to integrate several new techniques into a systematic study of a difficult problem.« less

A faint type of supernova from a white dwarf with a helium-rich companion.

PubMed

Perets, H B; Gal-Yam, A; Mazzali, P A; Arnett, D; Kagan, D; Filippenko, A V; Li, W; Arcavi, I; Cenko, S B; Fox, D B; Leonard, D C; Moon, D-S; Sand, D J; Soderberg, A M; Anderson, J P; James, P A; Foley, R J; Ganeshalingam, M; Ofek, E O; Bildsten, L; Nelemans, G; Shen, K J; Weinberg, N N; Metzger, B D; Piro, A L; Quataert, E; Kiewe, M; Poznanski, D

2010-05-20

Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The 'old' environment near the supernova location, and the very low derived ejected mass ( approximately 0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive (44)Ti.

The evolution of high-metallicity horizontal-branch stars and the origin of the ultraviolet light in elliptical galaxies

NASA Technical Reports Server (NTRS)

Horch, E.; Demarque, P.; Pinsonneault, M.

1992-01-01

Evolutionary calculations of high-metallicity horizontal-branch stars show that for the relevant masses and helium abundances, post-HB evolution in the HR diagram does not proceed toward and along the AGB, but rather toward a 'slow blue phase' in the vicinity of the helium-burning main sequence, following the extinction of the hydrogen shell energy source. For solar and twice solar metallicity, the blue phase begins during the helium shell-burning phase (in agreement with the work of Brocato and Castellani and Tornambe); for 3 times solar metallicity, it begins earlier, during the helium core-burning phase. This behavior differs from what takes place at lower metallicities. The implications for high-metallicity old stellar populations in the Galactic bulge and for the integrated colors of elliptical galaxies are discussed.

Reducing Uncertainties in the Production of the Gamma-emitting Nuclei {sup 26}Al, {sup 44}Ti, and {sup 60}Fe in Core-collapse Supernovae by Using Effective Helium Burning Rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Austin, Sam M.; West, Christopher; Heger, Alexander, E-mail: austin@nscl.msu.edu, E-mail: christopher.west@metrostate.edu, E-mail: Alexander.Heger@Monash.edu

2017-04-10

We have used effective reaction rates (ERRs) for the helium burning reactions to predict the yield of the gamma-emitting nuclei {sup 26}Al, {sup 44}Ti, and {sup 60}Fe in core-collapse supernovae (SNe). The variations in the predicted yields for values of the reaction rates allowed by the ERR are much smaller than obtained previously, and smaller than other uncertainties. A “filter” for SN nucleosynthesis yields based on pre-SN structure was used to estimate the effect of failed SNe on the initial mass function averaged yields; this substantially reduced the yields of all these isotopes, but the predicted yield ratio {sup 60}Fe/{supmore » 26}Al was little affected. The robustness of this ratio is promising for comparison with data, but it is larger than observed in nature; possible causes for this discrepancy are discussed.« less

Impact of managed moorland burning on peat nutrient and base cation status

NASA Astrophysics Data System (ADS)

Palmer, Sheila; Gilpin, Martin; Wearing, Catherine; Johnston, Kerrylyn; Holden, Joseph; Brown, Lee

2013-04-01

Controlled 'patch' burning of moorland vegetation has been used for decades in the UK to stimulate growth of heather (Calluna vulgaris) for game bird habitat and livestock grazing. Typically small patches (300-900 m2) are burned in rotations of 8-25 years. However, our understanding of the short-to-medium term environmental impacts of the practice on these sensitive upland areas has so far been limited by a lack of scientific data. In particular the effect of burning on concentrations of base cations and acid-base status of these highly organic soils has implications both for ecosystem nutrient status and for buffering of acidic waters. As part of the EMBER project peat chemistry data were collected in ten upland blanket peat catchments in the UK. Five catchments were subject to a history of prescribed rotational patch burning. The other five catchments acted as controls which were not subject to burning, nor confounded by other detrimental activities such as drainage or forestry. Soil solution chemistry was also monitored at two intensively studied sites (one regularly burned and one control). Fifty-centimetre soil cores, sectioned into 5-cm intervals, were collected from triplicate patches of four burn ages at each burned site, and from twelve locations at similar hillslope positions at each control site. At the two intensively monitored sites, soil solution chemistry was monitored at four depths in each patch. Across all sites, burned plots had significantly smaller cation exchange capacities, lower concentrations of exchangeable base cations and increased concentrations of exchangeable H+ and Al3+ in near-surface soil. C/N ratios were also lower in burned compared to unburned surface soils. There was no consistent trend between burn age and peat chemistry across all burned sites, possibly reflecting local controls on post-burn recovery rates or external influences on burn management decisions. At the intensively monitored site, plots burned less than two years prior to sampling had significantly smaller exchange capacities and lower concentrations of soil base cations in surface soils relative to plots burned 15-25 years previously. In contrast, surface soil solutions in recently burned plots were enriched in base cations relative to older plots and relative to the control site, possibly due to enhanced leaching at bare soil surfaces. The results offer evidence for an impact of burning on peat nutrient and acid-base status, but suggest that soils recover given time with no further burning.

Quantifying the effects of wildfire on changes in soil properties by surface burning of soils from the Boulder Creek Critical Zone Observatory

USGS Publications Warehouse

Wieting, Celeste; Ebel, Brian A.; Singha, Kamini

2017-01-01

Study regionThis study used intact soil cores collected at the Boulder Creek Critical Zone Observatory near Boulder, Colorado, USA to explore fire impacts on soil properties.Study focusThree soil scenarios were considered: unburned control soils, and low- and high-temperature burned soils. We explored simulated fire impacts on field-saturated hydraulic conductivity, dry bulk density, total organic carbon, and infiltration processes during rainfall simulations.New hydrological insights for the regionSoils burned to high temperatures became more homogeneous with depth with respect to total organic carbon and bulk density, suggesting reductions in near-surface porosity. Organic matter decreased significantly with increasing soil temperature. Tension infiltration experiments suggested a decrease in infiltration rates from unburned to low-temperature burned soils, and an increase in infiltration rates in high-temperature burned soils. Non-parametric statistical tests showed that field-saturated hydraulic conductivity similarly decreased from unburned to low-temperature burned soils, and then increased with high-temperature burned soils. We interpret these changes result from the combustion of surface and near-surface organic materials, enabling water to infiltrate directly into soil instead of being stored in the litter and duff layer at the surface. Together, these results indicate that fire-induced changes in soil properties from low temperatures were not as drastic as high temperatures, but that reductions in surface soil water repellency in high temperatures may increase infiltration relative to low temperatures.

Holocene Biomass Burning, Environmental Change, and Human Land Use in the Southern Maya Lowlands

NASA Astrophysics Data System (ADS)

Anderson, L.; Wahl, D.

2013-12-01

For several decades scholars have studied the dynamic relationship between the prehispanic Maya and their environment in order to test hypotheses that environmental change played a role in the abandonment of the Maya lowlands. Fire was inherent in Maya land use practices, arguably the primary tool used to alter the landscape and extract resources. Opening of forest for agriculture, building, and extraction/production of construction material necessitated burning. The extensive production of lime plaster for architectural and domestic use demanded harvesting and burning of vast quantities of green wood. While we understand the fundamental role of fire in Maya land use, there are very few records of prehispanic biomass burning from the Maya lowlands. Consequently, only a limited understanding exists of both natural fire regimes and patterns of anthropogenic burning in the tropical dry forests of Central America. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of fossil charcoal recovered from lacustrine sediment cores, extending from the early Holocene to the present. The study sites, Lagos Paixban and Puerto Arturo are located in the southern Maya lowlands in modern northern Peten, Guatemala. Macroscopic charcoal data are presented along with previously published proxy data from the sites, and interpreted in the context of existing regional and local paleoenvironmental and archeological records. Results show that frequent fires occurred in the closed canopy forests of the region since at least the early mid-Holocene (~9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of sedentary agriculture at around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Preclassic period suggest that land use strategies may have included intensive agricultural much earlier than previously thought. Preliminary results showing concentrations of soot/black carbon during the middle and late Preclassic periods have intriguing implications regarding the efficiency of Maya fuel consumption. This period marks a time of peak lime production requiring very high rates of biomass harvest and burning, yet concentration levels of soot/black carbon are lower than modern global background values.

Seismological Modeling of the Delta Scuti Star: CD-24 7599

NASA Astrophysics Data System (ADS)

Bradley, Paul A.; Guzik, Joyce A.

1996-01-01

A major goal of asteroseismology is a better understanding of stellar evolution via ''snapshots'' of many stars of different masses in different evolutionary states. For stars of about 2M(circle dot) near the sequence, b Scuti stars are the usual suspects. There is an ongoing renaissance in theoretical modeling of 6 Scuti stars brought on by improvements in constitutive physics and by a dramatic increase in the number of modes observed. FG Virginis and CD-24' 7599 are two of the best studied objects, and they have 19 and 13 known frequencies, respectively. . We create models using an updated and modified version of the Iben code described by Guzik & Cox that includes either of the two versions of the OPAL opacities . We use the star's observed location on the H-R diagram as a starting point for our seismological modeling. Because there is no evidence for observed t = 3 modes, we only consider l = 0, 1, and 2 modes in our analysis. We take into account rotational splitting (about 5 - 10 (mu)Hz) in our frequency matching. Several observed modes must be rotationally split members of a given mode. CD-24' 7599 is less than halfway through core hydrogen burning, and the modes appear to be a set of consecutive 3rd through 5th overtones of (ital l) = 0 through 2 modes. With only 13 modes, we find satisfactory fits with models between 1.9 and 2.0 M(circle dot) that fall within the observed luminosity and effective temperature range. By contrast, Guzik & Bradley suggest that FG Virginis is over halfway through core hydrogen burning and the best fitting models lie near 1.80 or 2.00 M(circle dot). We see persistent discrepancies in some low frequency modes, which suggests we may need a small amount of core overshoot or a slight change in metallicity to duplicate FG Virginis.

Multispectral imaging burn wound tissue classification system: a comparison of test accuracies between several common machine learning algorithms

NASA Astrophysics Data System (ADS)

Squiers, John J.; Li, Weizhi; King, Darlene R.; Mo, Weirong; Zhang, Xu; Lu, Yang; Sellke, Eric W.; Fan, Wensheng; DiMaio, J. Michael; Thatcher, Jeffrey E.

2016-03-01

The clinical judgment of expert burn surgeons is currently the standard on which diagnostic and therapeutic decisionmaking regarding burn injuries is based. Multispectral imaging (MSI) has the potential to increase the accuracy of burn depth assessment and the intraoperative identification of viable wound bed during surgical debridement of burn injuries. A highly accurate classification model must be developed using machine-learning techniques in order to translate MSI data into clinically-relevant information. An animal burn model was developed to build an MSI training database and to study the burn tissue classification ability of several models trained via common machine-learning algorithms. The algorithms tested, from least to most complex, were: K-nearest neighbors (KNN), decision tree (DT), linear discriminant analysis (LDA), weighted linear discriminant analysis (W-LDA), quadratic discriminant analysis (QDA), ensemble linear discriminant analysis (EN-LDA), ensemble K-nearest neighbors (EN-KNN), and ensemble decision tree (EN-DT). After the ground-truth database of six tissue types (healthy skin, wound bed, blood, hyperemia, partial injury, full injury) was generated by histopathological analysis, we used 10-fold cross validation to compare the algorithms' performances based on their accuracies in classifying data against the ground truth, and each algorithm was tested 100 times. The mean test accuracy of the algorithms were KNN 68.3%, DT 61.5%, LDA 70.5%, W-LDA 68.1%, QDA 68.9%, EN-LDA 56.8%, EN-KNN 49.7%, and EN-DT 36.5%. LDA had the highest test accuracy, reflecting the bias-variance tradeoff over the range of complexities inherent to the algorithms tested. Several algorithms were able to match the current standard in burn tissue classification, the clinical judgment of expert burn surgeons. These results will guide further development of an MSI burn tissue classification system. Given that there are few surgeons and facilities specializing in burn care, this technology may improve the standard of burn care for patients without access to specialized facilities.

Safety and core design of large liquid-metal cooled fast breeder reactors

NASA Astrophysics Data System (ADS)

Qvist, Staffan Alexander

In light of the scientific evidence for changes in the climate caused by greenhouse-gas emissions from human activities, the world is in ever more desperate need of new, inexhaustible, safe and clean primary energy sources. A viable solution to this problem is the widespread adoption of nuclear breeder reactor technology. Innovative breeder reactor concepts using liquid-metal coolants such as sodium or lead will be able to utilize the waste produced by the current light water reactor fuel cycle to power the entire world for several centuries to come. Breed & burn (B&B) type fast reactor cores can unlock the energy potential of readily available fertile material such as depleted uranium without the need for chemical reprocessing. Using B&B technology, nuclear waste generation, uranium mining needs and proliferation concerns can be greatly reduced, and after a transitional period, enrichment facilities may no longer be needed. In this dissertation, new passively operating safety systems for fast reactors cores are presented. New analysis and optimization methods for B&B core design have been developed, along with a comprehensive computer code that couples neutronics, thermal-hydraulics and structural mechanics and enables a completely automated and optimized fast reactor core design process. In addition, an experiment that expands the knowledge-base of corrosion issues of lead-based coolants in nuclear reactors was designed and built. The motivation behind the work presented in this thesis is to help facilitate the widespread adoption of safe and efficient fast reactor technology.

FAILURE OF A NEUTRINO-DRIVEN EXPLOSION AFTER CORE-COLLAPSE MAY LEAD TO A THERMONUCLEAR SUPERNOVA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kushnir, Doron; Katz, Boaz, E-mail: kushnir@ias.edu

We demonstrate that ∼10 s after the core-collapse of a massive star, a thermonuclear explosion of the outer shells is possible for some (tuned) initial density and composition profiles, assuming that the neutrinos failed to explode the star. The explosion may lead to a successful supernova, as first suggested by Burbidge et al. We perform a series of one-dimensional (1D) calculations of collapsing massive stars with simplified initial density profiles (similar to the results of stellar evolution calculations) and various compositions (not similar to 1D stellar evolution calculations). We assume that the neutrinos escaped with a negligible effect on themore » outer layers, which inevitably collapse. As the shells collapse, they compress and heat up adiabatically, enhancing the rate of thermonuclear burning. In some cases, where significant shells of mixed helium and oxygen are present with pre-collapsed burning times of ≲100 s (≈10 times the free-fall time), a thermonuclear detonation wave is ignited, which unbinds the outer layers of the star, leading to a supernova. The energy released is small, ≲10{sup 50} erg, and negligible amounts of synthesized material (including {sup 56}Ni) are ejected, implying that these 1D simulations are unlikely to represent typical core-collapse supernovae. However, they do serve as a proof of concept that the core-collapse-induced thermonuclear explosions are possible, and more realistic two-dimensional and three-dimensional simulations are within current computational capabilities.« less

Measurements of acetylene in air extracted from polar ice cores

NASA Astrophysics Data System (ADS)

Nicewonger, M. R.; Aydin, M.; Montzka, S. A.; Saltzman, E. S.

2016-12-01

Acetylene (ethyne) is a non-methane hydrocarbon emitted during combustion of fossil fuels, biofuels, and biomass. The major atmospheric loss pathway of acetylene is oxidation by hydroxyl radical with a lifetime estimated at roughly two weeks. The mean annual acetylene levels over Greenland and Antarctica are 250 ppt and 20 ppt, respectively. Firn air measurements suggest atmospheric acetylene is preserved unaltered in polar snow and firn. Atmospheric reconstructions based on firn air measurements indicate acetylene levels rose significantly during the twentieth century, peaked near 1980, then declined to modern day levels. This historical trend is similar to that of other fossil fuel-derived non-methane hydrocarbons. In the preindustrial atmosphere, acetylene levels should primarily reflect emissions from biomass burning. In this study, we present the first measurements of acetylene in preindustrial air extracted from polar ice cores. Air from fluid and dry-drilled ice cores from Summit, Greenland and WAIS-Divide Antarctica is extracted using a wet-extraction technique. The ice core air is analyzed using gas chromatography and high-resolution mass spectrometry. Between 1400 to 1800 C.E., acetylene levels over Greenland and Antarctica varied between roughly 70-120 ppt and 10-30 ppt, respectively. The preindustrial Greenland acetylene levels are significantly lower than modern levels, reflecting the importance of northern hemisphere fossil fuel sources today. The preindustrial Antarctic acetylene levels are comparable to modern day levels, indicating similar emissions in the preindustrial atmosphere, likely from biomass burning. The implications of the preindustrial atmospheric acetylene records from both hemispheres will be discussed.

The behaviour of transuranic mixed oxide fuel in a Candu-900 reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morreale, A. C.; Ball, M. R.; Novog, D. R.

2012-07-01

The production of transuranic actinide fuels for use in current thermal reactors provides a useful intermediary step in closing the nuclear fuel cycle. Extraction of actinides reduces the longevity, radiation and heat loads of spent material. The burning of transuranic fuels in current reactors for a limited amount of cycles reduces the infrastructure demand for fast reactors and provides an effective synergy that can result in a reduction of as much as 95% of spent fuel waste while reducing the fast reactor infrastructure needed by a factor of almost 13.5 [1]. This paper examines the features of actinide mixed oxidemore » fuel, TRUMOX, in a CANDU{sup R}* nuclear reactor. The actinide concentrations used were based on extraction from 30 year cooled spent fuel and mixed with natural uranium in 3.1 wt% actinide MOX fuel. Full lattice cell modeling was performed using the WIMS-AECL code, super-cell calculations were analyzed in DRAGON and full core analysis was executed in the RFSP 2-group diffusion code. A time-average full core model was produced and analyzed for reactor coefficients, reactivity device worth and online fuelling impacts. The standard CANDU operational limits were maintained throughout operations. The TRUMOX fuel design achieved a burnup of 27.36 MWd/kg HE. A full TRUMOX fuelled CANDU was shown to operate within acceptable limits and provided a viable intermediary step for burning actinides. The recycling, reprocessing and reuse of spent fuels produces a much more sustainable and efficient nuclear fuel cycle. (authors)« less

Convective-core Overshoot and Suppression of Oscillations: Constraints from Red Giants in NGC 6811

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arentoft, T.; Brogaard, K.; Jessen-Hansen, J.

Using data from the NASA spacecraft Kepler , we study solar-like oscillations in red giant stars in the open cluster NGC 6811. We determine oscillation frequencies, frequency separations, period spacings of mixed modes, and mode visibilities for eight cluster giants. The oscillation parameters show that these stars are helium-core-burning red giants. The eight stars form two groups with very different oscillation power spectra; the four stars with the lowest Δ ν values display rich sets of mixed l = 1 modes, while this is not the case for the four stars with higher Δ ν . For the four starsmore » with lowest Δ ν , we determine the asymptotic period spacing of the mixed modes, Δ P , which together with the masses we derive for all eight stars suggest that they belong to the so-called secondary clump. Based on the global oscillation parameters, we present initial theoretical stellar modeling that indicates that we can constrain convective-core overshoot on the main sequence and in the helium-burning phase for these ∼2 M {sub ⊙} stars. Finally, our results indicate less mode suppression than predicted by recent theories for magnetic suppression of certain oscillation modes in red giants.« less

Neutronics, steady-state, and transient analyses for the Poland MARIA reactor for irradiation testing of LEU lead test fuel assemblies from CERCA : ANL independent verification results.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garner, P. L.; Hanan, N. A.

The MARIA reactor at the Institute of Atomic Energy (IAE) in Swierk (30 km SE of Warsaw) in the Republic of Poland is considering conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel assemblies (FA). The FA design in MARIA is rather unique; a suitable LEU FA has never been designed or tested. IAE has contracted with CERCA (the fuel supply portion of AREVA in France) to supply 2 lead test assemblies (LTA). The LTAs will be irradiated in MARIA to burnup level of at least 40% for both LTAs and to 60% for one LTA. IAE may decidemore » to purchase additional LEU FAs for a full core conversion after the test irradiation. The Reactor Safety Committee within IAE and the National Atomic Energy Agency in Poland (PAA) must approve the LTA irradiation process. The approval will be based, in part, on IAE submitting revisions to portions of the Safety Analysis Report (SAR) which are affected by the insertion of the LTAs. (A similar process will be required for the full core conversion to LEU fuel.) The analysis required was established during working meetings between Argonne National Laboratory (ANL) and IAE staff during August 2006, subsequent email correspondence, and subsequent staff visits. The analysis needs to consider the current high-enriched uranium (HEU) core and 4 core configurations containing 1 and 2 LEU LTAs in various core positions. Calculations have been performed at ANL in support of the LTA irradiation. These calculations are summarized in this report and include criticality, burn-up, neutronics parameters, steady-state thermal hydraulics, and postulated transients. These calculations have been performed at the request of the IAE staff, who are performing similar calculations to be used in their SAR amendment submittal to the PAA. The ANL analysis has been performed independently from that being performed by IAE and should only be used as one step in the verification process.« less

Thulium fiber laser lithotripsy using tapered fibers.

PubMed

Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

2010-01-01

The Thulium fiber laser has recently been tested as a potential alternative to the Holmium:YAG laser for lithotripsy. This study explores use of a short taper for expanding the Thulium fiber laser beam at the distal tip of a small-core fiber. Thulium fiber laser radiation with a wavelength of 1,908 nm, 10 Hz pulse rate, 70 mJ pulse energy, and 1-millisecond pulse duration was delivered through a 2-m-length fiber with 150-microm-core-input-end, 300-microm-core-output-end, and 5-mm-length taper, in contact with human uric acid (UA) and calcium oxalate monohydrate (COM) stones, ex vivo (n = 10 each). Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, irrigation rates, and deflection through a flexible ureteroscope were measured for the tapered fiber and compared with conventional fibers. After delivery of 1,800 pulses through the tapered fiber, mass loss measured 12.7+/-2.6 mg for UA and 7.2+/-0.8 mg COM stones, comparable to conventional 100-microm-core fibers (12.6+/-2.5 mg for UA and 6.8+/-1.7 mg for COM stones). No transmission losses or burn-back occurred for the tapered fiber after 36,000 pulses, while a conventional 150-microm fiber experienced significant tip degradation after only 1,800 pulses. High irrigation rates were measured with the tapered fiber inserted through the working port of a flexible ureteroscope without hindering its deflection, mimicking that of a conventional 150 microm fiber. The short tapered distal fiber tip allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional small-core fibers, without compromising fiber bending, stone vaporization efficiency, or irrigation rates.

CARBON MONOXIDE FLUXES OF DIFFERENT SOIL LAYERS IN UPLAND CANADIAN BOREAL FORESTS

EPA Science Inventory

Dark or low-light carbon monoxide fluxes at upland Canadian boreal forest sites were measured on-site with static chambers and with a laboratory incubation technique using cores from different depths at the same sites. Three different upland black spruce sites, burned in 1987,199...

[Discipline construction is the theme of the development of burn surgery].

PubMed

Jia, C Y

2018-03-20

Discipline construction is the core element of department development, including discipline structure setting, scale, equipment, medical workers structure, clinical feature and advantage, talent training, teaching level, scientific research level, management system, and cultural construction of department. As leader and engine of discipline construction, directors' ability is an important factor for discipline construction. Clinical characteristic is the basis of discipline construction; innovation actuation is the essence of discipline construction; talents training is the guarantee of discipline construction; scientific research is the wing of discipline construction; cultural construction is the hot spring of discipline construction. Discipline construction is the theme of the development of burn surgery.

Deep learning classification in asteroseismology

NASA Astrophysics Data System (ADS)

Hon, Marc; Stello, Dennis; Yu, Jie

2017-08-01

In the power spectra of oscillating red giants, there are visually distinct features defining stars ascending the red giant branch from those that have commenced helium core burning. We train a 1D convolutional neural network by supervised learning to automatically learn these visual features from images of folded oscillation spectra. By training and testing on Kepler red giants, we achieve an accuracy of up to 99 per cent in separating helium-burning red giants from those ascending the red giant branch. The convolutional neural network additionally shows capability in accurately predicting the evolutionary states of 5379 previously unclassified Kepler red giants, by which we now have greatly increased the number of classified stars.

High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

NASA Technical Reports Server (NTRS)

Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

1987-01-01

Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

In view of standardization: comparison and analysis of initial management of severely burned patients in Germany, Austria and Switzerland.

PubMed

Münzberg, Matthias; Ziegler, Benjamin; Fischer, Sebastian; Wölfl, Christoph Georg; Grützner, Paul Alfred; Kremer, Thomas; Kneser, Ulrich; Hirche, Christoph

2015-02-01

Initial treatment of severely injured patients in German speaking trauma centers follows precise sequences. Several guidelines and training courses ensure a constant quality in providing evidence-based treatment for these patients. Similar standards, algorithms and guidelines for the treatment of severely burned patients are lacking. This raises the question about the current standard of care for burn victims in German speaking burn centers. In order to achieve standardization, as a first step this study surveys principles of burn room organization and management in these burn centers. A questionnaire including 40 questions regarding burn room organization, personnel structure and qualification, infrastructural conditions and quality management was developed and sent to 21 level one burn centers in Germany, Austria and Switzerland. The rate of returned questionnaires was 81%. The analysis revealed varying personnel and infrastructural conditions in participating burn centers. Indications for admission to the burn room and admission procedures itself are different throughout surveyed hospitals. Individual standard operating procedure (SOP) for burn trauma admissions was available in most burn centers and nearly all participants register their burn trauma cases using an in-house burn register. The survey suggests a lack of standardization in personnel structure, infrastructure and treatment approach for the initial clinical care of severely burned patients in burn centers across the German speaking countries. Further evaluation of existing protocols and international standards in burn care is inevitable to develop standardized guidelines for burn care and to improve quality of care. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Porous and Cellular Materials for Structural Applications; Symposium Held in San Francisco, California on April 13-15, 1998

DTIC Science & Technology

1998-04-01

Industrial Scale 179 M. Schmidt and F. Schwertfeger Structural Graphitic Carbon Foams 185 Kristen M. Kearns, David P. Anderson, and Heather J...Nanostructured Powders and Their Industrial Application, Q. Beaucage, J.E. Mark, Q. Burns, H. Duen-Wu, 1998, ISBN: 1-55899-426-2 Volume 521—Porous and Cellular...has faces which are 0.03" thick and the core is 0.4" thick. Bonding between the core and face is achieved using a standard industrial epoxy adhesive

Electron-ion relaxation in a dense plasma. [supernovae core physics

NASA Technical Reports Server (NTRS)

Littleton, J. E.; Buchler, J.-R.

1974-01-01

The microscopic physics of the thermonuclear runaway in highly degenerate carbon-oxygen cores is investigated to determine if and how a detonation wave is generated. An expression for the electron-ion relaxation time is derived under the assumption of large degeneracy and extreme relativity of the electrons in a two-temperature plasma. Since the nuclear burning time proves to be several orders of magnitude shorter than the relaxation time, it is concluded that in studying the structure of the detonation wave the electrons and ions must be treated as separate fluids.

A bibliometric analysis of the 100 most influential papers in burns.

PubMed

Joyce, C W; Kelly, J C; Sugrue, C

2014-02-01

The importance of a published paper to a particular area is reflected in the quantity of citations obtained from peers. In burns, it is unknown which papers have been the most influential on this specialty. The purpose of our study was to identify the 100 most cited papers in burns and to analyze their characteristics. Twenty-seven journals were chosen for analysis. These included high impact factor scientific journals and journals dedicated to burns and trauma. Only twelve of these journals contributed to the 100 most cited papers in burns and we analyzed each paper individually looking at its subject matter, authorship, article type, institution, country and year of publication. Our citation analysis revealed an interesting mix of clinical and scientific papers that documents the key landmarks in burn care over the past 66 years. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Chemical Characterization of Individual Particles and Residuals of Cloud Droplets and Ice Crystals Collected On Board Research Aircraft in the ISDAC 2008 Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiranuma, Naruki; Brooks, Sarah D.; Moffet, Ryan C.

2013-06-24

Although it has been shown that size of atmospheric particles has a direct correlation with their ability to act as cloud droplet and ice nuclei, the influence of composition of freshly emitted and aged particles in nucleation processes is poorly understood. In this work we combine data from field measurements of ice nucleation with chemical imaging of the sampled particles to link aerosol composition with ice nucleation ability. Field measurements and sampling were conducted during the Indirect and Semidirect Aerosols Campaign (ISDAC) over Barrow, Alaska, in the springtime of 2008. In-situ ice nucleation measurements were conducted using a Continuous Flowmore » Diffusion Chamber (CFDC). Measured number concentrations of ice nuclei (IN) varied from frequent values of 0.01 per liter to more than 10 per liter. Residuals of airborne droplets and ice crystals were collected through a counterflow virtual impactor (CVI). The compositions of individual atmospheric particles and the residuals were studied using Computer Controlled Scanning Electron Microscopy with Energy Dispersive X-ray analysis (CCSEM/EDX) and Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (STXM/NEXAFS). Chemical analysis of cloud particle residuals collected during an episode of high ice nucleation suggests that both size and composition may influence aerosol's ability to act as IN. The STXM/NEXAFS chemical composition maps of individual residuals have characteristic structures of either inorganic or black carbon cores coated by organic materials. In a separate flight, particle samples from a biomass burning plume were collected. Although it has previously been suggested that episodes of biomass burning contribute to increased numbers of highly effective ice nuclei, in this episode we observed that only a small fraction were effective ice nuclei. Most of the particles from the biomass plume episode were smaller in size and were composed of homogeneous organic material without identifiable cores.« less

Soil properties and root biomass responses to prescribed burning in young Corsican pine (Pinus nigra Arn.) stands.

PubMed

Tufekcioglu, Aydin; Kucuk, Mehmet; Saglam, Bulent; Bilgili, Ertugrul; Altun, Lokman

2010-05-01

Fire is an important tool in the management of forest ecosystems. Although both prescribed and wildland fires are common in Turkey, few studies have addressed the influence of such disturbances on soil properties and root biomass dynamics. In this study, soil properties and root biomass responses to prescribed fire were investigated in 25-year-old corsican pine (Pinus nigra Arn.) stands in Kastamonu, Turkey. The stands were established by planting and were subjected to prescribed burning in July 2003. Soil respiration rates were determined every two months using soda-lime method over a two-year period. Fine (0-2 mm diameter) and small root (2-5 mm diameter) biomass were sampled approximately bimonthly using sequential coring method. Mean daily soil respiration ranged from 0.65 to 2.19 g Cm(-2) d(-1) among all sites. Soil respiration rates were significantly higher in burned sites than in controls. Soil respiration rates were correlated significantly with soil moisture and soil temperature. Fine root biomass was significantly lower in burned sites than in control sites. Mean fine root biomass values were 4940 kg ha(-1) for burned and 5450 kg ha(-1) for control sites. Soil pH was significantly higher in burned sites than in control sites in 15-35 cm soil depth. Soil organic matter content did not differ significantly between control and burned sites. Our results indicate that, depending on site conditions, fire could be used successfully as a tool in the management of forest stands in the study area.

Dredge-up and Envelope Burning in Intermediate-Mass Giants of Very Low Metallicity

NASA Astrophysics Data System (ADS)

Herwig, Falk

2004-04-01

The evolution of intermediate-mass stars at very low metallicity during their final thermal pulse asymptotic giant branch (AGB) phase is studied in detail. As representative examples, models with initial masses of 4 and 5Msolar and with a metallicity of Z=0.0001 ([Fe/H]~-2.3) are discussed. The one-dimensional stellar structure and evolution model includes time- and depth-dependent overshooting motivated by hydrodynamic simulations, as well as a full nuclear network and time-dependent mixing. Particular attention is given to high time and space resolution to avoid numerical artifacts related to third dredge-up and hot bottom burning predictions. The model calculations predict very efficient third dredge-up that mixes the envelope with the entire intershell layer or a large fraction thereof and in some cases penetrates into the C/O core below the He shell. In all cases primary oxygen is mixed into the envelope. The models predict efficient envelope burning during the interpulse phase. Depending on the envelope-burning temperature, oxygen is destroyed to varying degrees. The combined effect of dredge-up and envelope burning does not lead to any significant oxygen depletion in any of the cases considered in this study. The large dredge-up efficiency in our model is closely related to the particular properties of the H shell during the dredge-up phase in low-metallicity very metal-poor stars, which is followed here over many thermal pulses. During the dredge-up phase, the temperature just below the convective boundary is large enough for protons to burn vigorously when they are brought into the C-rich environment below the convection boundary by the time- and depth-dependent overshooting. H-burning luminosities of 105 to ~2×106Lsolar are generated. C, and to lesser degree O, is transformed into N in this dredge-up overshooting layer and enters the envelope. The global effect on the CNO abundance is similar to that of hot bottom burning. If the overshoot efficiency is larger, then dredge-up H burning causes a further increase in the dredge-up efficiency. After some thermal pulses, the dredge-up proceeds through the He shell and into the CO core beneath. Then neutrons may not be released from 13C in radiative conditions during the interpulse phase because of the scarcity of α-particles for the 13C(α,n)16O reactions. Conditions for the s-process are discussed qualitatively. The abundance evolution of H, He, C, N, O, and Na is described. Finally, the model predictions for sodium and oxygen are compared with observed abundances. The notion that massive AGB stars are the origin of the O-Na abundance anticorrelation in globular cluster giants is not consistent with the model predictions of this study. The abundance of the C-rich extremely metal-poor binaries LP 625-44, CS 29497-030, and HE 0024-2523 is discussed.

What's in a story? A text analysis of burn survivors' web-posted narratives.

PubMed

Badger, Karen; Royse, David; Moore, Kelly

2011-01-01

Story-telling has been found to be beneficial following trauma, suggesting a potential intervention for burn survivors who frequently make use of? telling their story? as part of their recovery. This study is the first to examine the word content of burn survivors' Web-posted narratives to explore their perceptions of the event, supportive resources, their post-burn well-being, and re-integration using a comparison group and a text data analysis software developed by the widely recognized James Pennebaker. Suggestions for using expressive writing or story-telling as a guided psychosocial intervention with burn survivors are made.

Aetiology of adult burns treated from 2000 to 2012 in a Swiss University Hospital.

PubMed

Müller, M; Moser, E M; Pfortmueller, C A; Olariu, R; Lehmann, B; Exadaktylos, A K

2016-06-01

Burns in Switzerland are frequent and lead to high economic and social costs. However, little is known about the aetiology of burns suffered by patients seeking treatment in hospital emergency departments. This knowledge could be used to develop preventive measures. This retrospective analysis included all patients (≥16 years old) with acute thermal injuries of known cause admitted to the adult emergency department in Bern University Hospital (Switzerland, not a specialised burns unit) between 2000 and 2012. Clinical and sociodemographic data were extracted from medical records, i.e. the environment in which the burn occurred, as well as details of burn severity and aetiology. Seven hundred and one (701) patients with a mean age of 35.0±14.5 years (56% men) were included in the analysis. The winter season and the days around Christmas, turn of the year and Swiss National Day were identified as times with high risk of burns. Household (45%) and workplace (31%) were the most common locations/settings in which the burns occurred. Approximately every second burn was caused by scald, every fourth by flame and every seventh by hot objects. The analysis identified cooking, tar and electricity in workplace accidents, barbecues and the use of gasoline as aetiological factors in burns in leisure time, together with water in domestic thermal injuries. Burns occurred predominantly on non-protected skin on the hand and arms. The most severe burns were seen in electrical and flame burns. Men suffered more severe burns than women in all settings except psychopathology. The data suggest that the incidence and severity of burns in Switzerland could be reduced by preventive strategies and public campaigns, including education on fire protection systems, raising awareness about the times and locations where the risks of burns are greater, further improvement in workplace safety, particularly with cooking facilities and electrical equipment, and the development of innovative safety devices (i.e. machines, protective gloves). These findings have to be interpreted carefully, as this study includes only adult patients who presented in our ED and, in most cases, the burns covered less than 20% of the body surface. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Epidemiology of U.K. Military Burns 2008-2013.

PubMed

Page, Felicity; Hamnett, Nathan; D'Asta, Federica; Jeffery, Steven

After sustaining burn injuries overseas, U.K. Armed Forces personnel are evacuated to the Royal Centre for Defence Medicine. The objective was to review the etiology of U.K. Military burns managed at the center between 2008 and 2013. Analysis will aid provision planning and assist in the prevention of burn injuries for future tours. The International Burn Injury Database database of all U.K. Armed Forces burn injured patients evacuated to the Queen Elizabeth University Hospital Birmingham between 2008 and 2013 were reviewed retrospectively. Analysis included patient demographics, injury mechanism, burn severity, management, and mortality. There were 65 military personnel with burn injuries requiring repatriation to the United Kingdom. Percentage of 78.5 were sustained in Afghanistan. The mean age was 25 (18-46) years. Percentage of 70.8 were considered noncombat burn injuries. Of the noncombat burns, the mechanism of injury most commonly involved burning waste and misuse of fuels and scalds. The mean TBSA for all patients was 6% (0.05-51%). Areas most commonly affected included arms, legs, and face. The length of hospital stay for combat vs noncombat burn injury patients was 10 vs 7 days. There were no fatalities. In conclusion, substantially fewer military personnel sustained combat burns between 2008 and 2013 than in preceding study period (19 vs 79). The number of accidental noncombat burns remained constant. The decrease in combat burns may reflect a relative decrease in military intensity and effective protective equipment and safety measures. Further education may allow for an additional decrease in preventable burn injuries.

Topical local anaesthetics (EMLA) inhibit burn-induced plasma extravasation as measured by digital image colour analysis.

PubMed

Jönsson, A; Mattsson, U; Tarnow, P; Nellgård, P; Cassuto, J

1998-06-01

Amide local anaesthetics have previously been shown to reduce oedema and improve dermal perfusion following experimental burns. Previous studies have used invasive techniques for burn oedema quantification which do not allow continuous monitoring in the same animal. The present study used digital image colour analysis to investigate the effect of topical local anaesthetics on burn-induced extravasation of Evans blue albumin. A standardised full-thickness burn injury (1 x 1 cm) was induced in the abdominal skin of anaesthetised rats. The burn area was subsequently covered with 0.5 g of lidocaine-prilocaine cream 5% (25 mg of each in 1 g; EMLA, ASTRA, Sweden) or placebo cream during the first hour post-burn. One hour after the burn trauma, animals received Evans blue dye intravenously. Skin colour appearances were recorded by macrophotography before the burn and 5, 60. 65, 90, 120, 150, and 180 min post-burn. Colour slides were digitised and colour changes were analysed using the normalised red-green-blue (n-rgb) colour system. Results showed a significant inhibition of Evans blue extravasation between 60 and 180 min post-burn in EMLA-treated animals versus controls. Topical local anaesthetics are potent inhibitors of burn-induced plasma albumin extravasation, probably by direct action on vascular permeability and by inhibition of various steps of the pathophysiological response after burn injury.

On the influence of biomass burning on the seasonal CO2 signal as observed at monitoring stations

USGS Publications Warehouse

Wittenberg, U.; Heimann, Martin; Esse, G.; McGuire, A.D.; Sauf, W.

1998-01-01

We investigated the role of biomass burning in simulating the seasonal signal in both prognostic and diagnostic analyses. The prognostic anaysis involved the High-Resolution Biosphere Model, a prognostic terrestrial biosphere model, and the coupled vegetation fire module, which together produce a prognostic data set of biomass burning. The diagnostic analysis invovled the Simple Diagnostic Biosphere Model (SDBM) and the Hao and Liu [1994] diagnostic data set of bimass burning, which have been scaled to global 2 and 4 Pg C yr-1, respectively. The monthly carbon exchange fields between the atmosphere and the biosphere with a spatial resolution of 0.5?? ?? 0.5??, the seasonal atmosphere-ocean exchange fields, and the emissions from fossil fuels have been coupled to the three-dimensional atmospheric transport model TM2. We have chosen eight monitoring stations of the National Oceanic and Atmospheric Administration network to compare the predicted seasonal atmospheric CO2 signals with those deduced from atmosphere-biosphere carbon exchange fluxes without any contribution from biomass burning. The prognostic analysis and the diagnostic analysis with global burning emissions of 4 Pg C yr-1 agree with respect to the change in the amplitude of the seasonal CO2 concentration introduced through biomass burning. We find that the seasonal CO2 signal at stations in higher northern latitudes (north of 30??N) is marginally influenced by biomass burning. For stations in tropical regions an increase in the CO2 amplitude of more an 1 oppmv (up to 50% with respect to the observed trough to peak amplitude) has been calculated. Biomass burning at stations farther south accounts for an increase in the CO2 amplitude of up to 59% (0.6 ppmv). A change in the phase of the seasonal CO2 signal at tropical and southern stations has been shown to be strongly influenced by the onset of biomass burning in southern tropical Africa and America. Comparing simulated and observed seasonal CO2 signals, we find higher discrepancies at southern troical stations if biomass burning emissions are included. This is caused by the additional increase in the amplitude in the prognostic analysis and a phase shift in a diagnostic analysis. In contrast, at the northern tropical stations biomass burning tends to improve the estimates of the seasonal CO2 signal in the prognostic analysis because of strengthening of the amplitude. Since the SDCM predicts the seasonal CO2 signal resonably well for the northern hemisphere tropical stations, no general improvement of the fit occurs if biomass burning emissions are considered.

Qualitative analysis of a psychological supportive counseling group for burn survivors and families in Malawi.

PubMed

Barnett, Brian S; Mulenga, Macjellings; Kiser, Michelle M; Charles, Anthony G

2017-05-01

While psychological care, including supportive group therapy, is a mainstay of burn treatment in the developed world, few reports of support groups for burn survivors and their caregivers in the developing world exist. This study records the findings of a support group in Malawi and provides a qualitative analysis of thematic content discussed by burn survivors and caregivers. We established a support group for burn survivors and caregivers from February-May 2012 in the burn unit at Kamuzu Central Hospital in Lilongwe, Malawi. Sessions were held weekly for twelve weeks and led by a Malawian counselor. The group leader compiled transcripts of each session and these transcripts were qualitatively analyzed for thematic information. Thematic analysis demonstrated a variety of psychological issues discussed by both survivors and caregivers. Caregivers discussed themes of guilt and self-blame for their children's injuries, worries about emotional distance now created between caregiver and survivor, fears that hospital admission meant likely patient death and concerns about their child's future and burn associated stigma. Burn survivors discussed frustration with long hospitalization courses, hope created through interactions with hospital staff, the association between mental and physical health, rumination about their injuries and how this would affect their future, decreased self-value, increased focus on their own mortality and family interpersonal difficulties. The establishment of a support group in our burn unit provided a venue for burn survivors and their families to discuss subjective experiences, as well as the dissemination of various coping techniques. Burn survivors and their caregivers in Malawi would benefit from the establishment of similar groups in the future to help address the psychological sequelae of burns. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

An Argument for Weakly Magnetized, Slowly Rotating Progenitors of Long Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Moreno Méndez, Enrique

2014-01-01

Using binary evolution with Case-C mass transfer, the spins of several black holes (BHs) in X-ray binaries (XBs) have been predicted and confirmed (three cases) by observations. The rotational energy of these BHs is sufficient to power up long gamma-ray bursts (GRBs) and hypernovae (HNe) and still leave a Kerr BH behind. However, strong magnetic fields and/or dynamo effects in the interior of such stars deplete their cores from angular momentum preventing the formation of collapsars. Thus, even though binaries can produce Kerr BHs, most of their rotation is acquired from the stellar mantle, with a long delay between BH formation and spin up. Such binaries would not form GRBs. We study whether the conditions required to produce GRBs can be met by the progenitors of such BHs. Tidal-synchronization and Alfvén timescales are compared for magnetic fields of different intensities threading He stars. A search is made for a magnetic field range that allows tidal spin up all the way in to the stellar core but prevents its slow down during differential rotation phases. The energetics for producing a strong magnetic field during core collapse, which may allow for a GRB central engine, are also estimated. An observationally reasonable choice of parameters is found (B <~ 102 G threading a slowly rotating He star) that allows Fe cores to retain substantial angular momentum. Thus, the Case-C mass-transfer binary channel is capable of explaining long GRBs. However, the progenitors must have low initial spin and low internal magnetic field throughout their H-burning and He-burning phases.

Outcomes important to burns patients during scar management and how they compare to the concepts captured in burn-specific patient reported outcome measures.

PubMed

Jones, Laura L; Calvert, Melanie; Moiemen, Naiem; Deeks, Jonathan J; Bishop, Jonathan; Kinghorn, Philip; Mathers, Jonathan

2017-12-01

Pressure garment therapy (PGT) is an established treatment for the prevention and treatment of hypertrophic scarring; however, there is limited evidence for its effectiveness. Burn survivors often experience multiple issues many of which are not adequately captured in current PGT trial measures. To assess the effectiveness of PGT it is important to understand what outcomes matter to patients and to consider whether patient-reported outcome measures (PROMs) can be used to ascertain the effect of treatments on patients' health-related quality of life. This study aimed to (a) understand the priorities and perspectives of adult burns patients and the parents of burns patients who have experienced PGT via in-depth qualitative data, and (b) compare these with the concepts captured within burn-specific PROMs. We undertook 40 semi-structured interviews with adults and parents of paediatric and adolescent burns patients who had experienced PGT to explore their priorities and perspectives on scar management. Interviews were audio-recorded, transcribed and thematically analysed. The outcomes interpreted within the interview data were then mapped against the concepts captured within burn-specific PROMs currently in the literature. Eight core outcome domains were identified as important to adult patients and parents: (1) scar characteristics and appearance, (2) movement and function, (3) scar sensation, (4) psychological distress, adjustments and a sense of normality, (5) body image and confidence, (6) engagement in activities, (7) impact on relationships, and (8) treatment burden. The outcome domains presented reflect a complex holistic patient experience of scar management and treatments such as PGT. Some currently available PROMs do capture the concepts described here, although none assess psychological adjustments and attainment of a sense of normality following burn injury. The routine use of PROMs that represent patient experience and their relative contribution to trial outcome assessment versus clinical measures is now a matter for further research and debate. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Constraints on CEMP-no progenitors from nuclear astrophysics

NASA Astrophysics Data System (ADS)

Choplin, Arthur; Maeder, André; Meynet, Georges; Chiappini, Cristina

2016-09-01

Context. The CEMP-no stars are long-lived small mass stars presenting a very low iron content and overabundances of carbon with no sign or only very weak signs of s- or r-elements. Although the origin of this abundance pattern is still a matter of debate, it was very likely inherited from a previous massive star, which we call the source star. Aims: We rely on a recent classification of CEMP-no stars arguing that some of them are made of a material processed by hydrogen burning that was enriched in products of helium burning during the nuclear life of the source star. We examine the possibility of forming CEMP-no stars with this material. Methods: We study the nucleosynthesis of the CNO cycle and the Ne-Na Mg-Al chains in a hydrogen burning single zone while injecting the helium burning products 12C, 16O, 22Ne, and 26Mg. We investigate the impact of changing density, temperature and the injection rate. The nuclear reaction rates involving the creation and destruction of 27Al are also examined. Results: 14N, 23Na, 24Mg, and 27Al are formed when injecting 12C, 16O, 22Ne, and 26Mg in the hydrogen burning zone. The 12C/13C ratio is constant under various conditions in the hydrogen burning zone. The predicted [Al/Fe] ratio varies up to ~ 2 dex depending on the prescription used for the reaction rates involving 27Al. Conclusions: The experiments we carried out support the view that some CEMP-no stars are made of a material processed by hydrogen burning that comes from a massive star experiencing mild to strong rotational mixing. During its burning, this material was likely enriched in helium burning products. No material coming from the carbon-oxygen rich core of the source star should be added to form the daughter star, otherwise the 12C/13C ratio would be largely above the observed range of values.

Return of the Tug-of-War

ERIC Educational Resources Information Center

McNamara, Julie

2017-01-01

Long before the release of the Common Core State Standards (CCSSI 2010), the Mathematical Tug-of-War was engaging students in the type of reasoning and problem solving described by the Standards for Mathematical Practice (SMP). In this updated version of a Marilyn Burns task, students use algebraic reasoning to determine the outcome of a contest…

Two New Super Li-rich Core He-burning Giants: A New Twist to the Long Tale of Li Enhancement in K Giants

NASA Astrophysics Data System (ADS)

Bharat Kumar, Yerra; Singh, Raghubar; Eswar Reddy, B.; Zhao, Gang

2018-05-01

In this Letter we report two new super Li-rich K giants, KIC2305930 and KIC12645107, with Li abundances exceeding that of the interstellar medium (ISM; A(Li) ≥ 3.2 dex). Importantly, both of the giants have been classified as core He-burning red clump (RC) stars based on asteroseismic data from Kepler mission. Also, both of the stars are found to be low mass (M ≈ 1.0 M ⊙), which, together with an evidence of their evolutionary status of being RC stars, implies that the stars have gone through both the luminosity bump and He-flash during their red giant branch (RGB) evolution. The stars’ large Li abundance and evolutionary phase suggest that Li enrichment occurred very recently, probably at the tip of the RGB either during He-flash, an immediate preceding event on the RGB, or by some kind of external event such as merger of an RGB star with white dwarf. The findings will provide critical constraints to theoretical models for understanding of Li enhancement origin in RGB stars.

The investigation of critical burning of fuel droplets

NASA Technical Reports Server (NTRS)

Allison, C. B.; Canada, G. S.; Faeth, G. M.

1973-01-01

The combustion and evaporation of liquid fuels at high pressures were investigated. Particular emphasis was placed on conditions where the liquid surface approaches the thermodynamic critical point during combustion. The influence of transient effects on a burning liquid fuel was also investigated through both analysis and measurements of the response of liquid monopropellant combustion to imposed pressure oscillations. Work was divided into four phases (1) Droplet combustion at high pressures, which consider both measurement and analysis of the porous sphere burning rate of liquids in a natural convection environment at elevated pressure. (2) High pressure droplet burning in combustion gases, which involved steady burning and evaporation of liquids from porous spheres in a high pressure environment that simulates actual combustion chamber conditions. (3) Liquid strand combustion, which considered the burning rate, the state of the liquid surface and the liquid phase temperature distribution of a burning liquid monopropellant column over a range of pressures. (4) Oscillatory combustion, which was a theoretical and experimental investigation of the response of a burning liquid monopropellant to pressure oscillations.

Variability of Black Carbon Deposition to the East Antarctic Plateau, 1800-2000 AD

NASA Technical Reports Server (NTRS)

Bisiaux, M. M.; Edwards, R.; McConnell, J. R.; Albert, M. R.; Anschutz, H.; Neumann, T. A.; Isaksson, E.; Penner, J. E.

2012-01-01

Refractory black carbon aerosols (rBC) from biomass burning and fossil fuel combustion are deposited to the Antarctic ice sheet and preserve a history of emissions and long-range transport from low- and mid-latitudes. Antarctic ice core rBC records may thus provide information with respect to past combustion aerosol emissions and atmospheric circulation. Here, we present six East Antarctic ice core records of rBC concentrations and fluxes covering the last two centuries with approximately annual resolution (cal. yr. 1800 to 2000). The ice cores were drilled in disparate regions of the high East Antarctic ice sheet, at different elevations and net snow accumulation rates. Annual rBC concentrations were log-normally distributed and geometric means of annual concentrations ranged from 0.10 to 0.18 m cro-g/kg. Average rBC fluxes were determined over the time periods 1800 to 2000 and 1963 to 2000 and ranged from 3.4 to 15.5 m /a and 3.6 to 21.8 micro-g/sq m/a, respectively. Geometric mean concentrations spanning 1800 to 2000 increased linearly with elevation at a rate of 0.025 micro-g/kg/500 m. Spectral analysis of the records revealed significant decadal-scale variability, which at several sites was comparable to decadal ENSO variability.

Thermonuclear runaways in nova outbursts. 2: Effect of strong, instantaneous, local fluctuations

NASA Technical Reports Server (NTRS)

Shankar, Anurag; Arnett, David

1994-01-01

In an attempt to understand the manner in which nova outbursts are initiated on the surface of a white dwarf, we investigate the effects fluctuations have on the evolution of a thermonuclear runaway. Fluctuations in temperature density, or the composition of material in the burning shell may arise due to the chaotic flow field generated by convection when it occurs, or by the accretion process itself. With the aid of two-dimensional reactive flow calculations, we consider cases where a strong fluctutation in temperature arises during the early, quiescent accretion phase or during the later, more dynamic, explosion phase. In all cases we find that an instantaneous, local temperature fluctuation causes the affected material to become Rayleigh-Taylor unstable. The rapid rise and subsequent expansion of matter immediately cools the hot blob, which prevents the lateral propagation of burning. This suggests that local temperature fluctuations do not play a significant role in directly initiating the runaway, especially during the early stages. However, they may provide an efficient mechanism of mixing core material into the envelope (thereby pre-enriching the fuel for subsequent episodes of explosive hydrogen burning) and of mixing substantial amounts of the radioactive nucleus N-13 into the surface layers, making novae potential gamma-ray sources. This suggests that it is the global not the local, evolution of the core-envelope interface to high temperatures which dominates the development of the runaway. We also present a possible new scenario for the initiation of nova outbursts based on our results.

Analysis of Alaskan burn severity patterns using remotely sensed data

USGS Publications Warehouse

Duffy, P.A.; Epting, J.; Graham, J.M.; Rupp, T.S.; McGuire, A.D.

2007-01-01

Wildland fire is the dominant large-scale disturbance mechanism in the Alaskan boreal forest, and it strongly influences forest structure and function. In this research, patterns of burn severity in the Alaskan boreal forest are characterised using 24 fires. First, the relationship between burn severity and area burned is quantified using a linear regression. Second, the spatial correlation of burn severity as a function of topography is modelled using a variogram analysis. Finally, the relationship between vegetation type and spatial patterns of burn severity is quantified using linear models where variograms account for spatial correlation. These results show that: 1) average burn severity increases with the natural logarithm of the area of the wildfire, 2) burn severity is more variable in topographically complex landscapes than in flat landscapes, and 3) there is a significant relationship between burn severity and vegetation type in flat landscapes but not in topographically complex landscapes. These results strengthen the argument that differential flammability of vegetation exists in some boreal landscapes of Alaska. Additionally, these results suggest that through feedbacks between vegetation and burn severity, the distribution of forest vegetation through time is likely more stable in flat terrain than it is in areas with more complex topography. ?? IAWF 2007.

A 10-year experience with major burns from a non-burn intensive care unit.

PubMed

Ibarra Estrada, Miguel Ángel; Chávez Peña, Quetzalcóatl; García Guardado, Dante Ismael; López Pulgarín, José Arnulfo; Aguirre Avalos, Guadalupe; Corona Jiménez, Federico

2014-09-01

The aim of this study was to review clinical data and outcomes of patients with burns in a Mexican non-burn intensive care unit (ICU). We did a retrospective analysis of our single-centre database of burn patients admitted to the ICU in the Hospital Civil Fray Antonio Alcalde (University Hospital). The sample was divided for analysis into two groups according to the outcome 'death' or 'discharge' from ICU. Overall mortality was 58.2%, without a decreasing trend in mortality rates through the years. We identified the presence of third-degree burns (odds ratio (OR) 1.5, p=0.003), and >49% total burned surface area (TBSA; OR 3.3, p≤0.001) was associated with mortality. Mean age was higher in deceased patients (38.2 years vs. 31.3 years, p=0.003) as was the TBSA (62.8% vs. 36.4%, p≤0.001). At multivariate analysis, inhalation injury was not associated with increased mortality, but it was with more mechanical ventilation days. Early surgical debridement/cleansing was performed in most patients; however, the mean of the procedures was 1.7 per patient in both groups. We identified significant factors associated with mortality. These variables and prognosis from non-burn ICUs differ broadly compared with burn intensive care units (BICUs); thus, more structured, multidisciplinary and specialised treatment strategies are still needed. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

NUCLEAR REACTOR CONTROL SYSTEM

DOEpatents

Howard, D.F.; Motta, E.E.

1961-06-27

A method for controlling the excess reactivity in a nuclear reactor throughout the core life while maintaining the neutron flux distribution at the desired level is described. The control unit embodies a container having two electrodes of different surface area immersed in an electrolytic solution of a good neutron sbsorbing metal ion such as boron, gadolinium, or cadmium. Initially, the neutron absorber is plated on the larger electrode to control the greater neutron flux of a freshly refueled core. As the fuel burns up, the excess reactivity decreases and the neutron absorber is then plated onto the smaller electrode so that the number of neutrons absorbed also decreases. The excess reactivity in the core may thus be maintained without the introduction of serious perturbations in the neutron flux distributibn.

Basidiomycete fungal communities in Australian sclerophyll forest soil are altered by repeated prescribed burning.

PubMed

Anderson, Ian C; Bastias, Brigitte A; Genney, David R; Parkin, Pamela I; Cairney, John W G

2007-04-01

Soil basidiomycetes play key roles in forest nutrient and carbon cycling processes, yet the diversity and structure of below ground basidiomycete communities remain poorly understood. Prescribed burning is a commonly used forest management practice and there is evidence that single fire events can have an impact on soil fungal communities but little is known about the effects of repeated prescribed burning. We have used internal transcribed spacer (ITS) terminal restriction fragment length polymorphism (T-RFLP) analysis to investigate the impacts of repeated prescribed burning every two or four years over a period of 30 years on soil basidiomycete communities in an Australian wet sclerophyll forest. Detrended correspondence analysis of ITS T-RFLP profiles separated basidiomycete communities in unburned control plots from those in burned plots, with those burned every two years being the most different from controls. Burning had no effect on basidiomycete species richness, thus these differences appear to be due to changes in community structure. Basidiomycete communities in the unburned control plots were vertically stratified in the upper 20 cm of soil, but no evidence was found for stratification in the burned plots, suggesting that repeated prescribed burning results in more uniform basidiomycete communities. Overall, the results demonstrate that repeated prescribed burning alters soil basidiomycete communities, with the effect being greater with more frequent burning.

A Unified tool to estimate Distances, Ages, and Masses (UniDAM) from spectrophotometric data

NASA Astrophysics Data System (ADS)

Mints, Alexey; Hekker, Saskia

2017-08-01

Context. Galactic archaeology, the study of the formation and evolution of the Milky Way by reconstructing its past from its current constituents, requires precise and accurate knowledge of stellar parameters for as many stars as possible. To achieve this, a number of large spectroscopic surveys have been undertaken and are still ongoing. Aims: So far consortia carrying out the different spectroscopic surveys have used different tools to determine stellar parameters of stars from their derived effective temperatures (Teff), surface gravities (log g), and metallicities ([Fe/H]); the parameters can be combined with photometric, astrometric, interferometric, or asteroseismic information. Here we aim to homogenise the stellar characterisation by applying a unified tool to a large set of publicly available spectrophotometric data. Methods: We used spectroscopic data from a variety of large surveys combined with infrared photometry from 2MASS and AllWISE and compared these in a Bayesian manner with PARSEC isochrones to derive probability density functions (PDFs) for stellar masses, ages, and distances. We treated PDFs of pre-helium-core burning, helium-core burning, and post helium-core burning solutions as well as different peaks in multimodal PDFs (I.e. each unimodal sub-PDF) of the different evolutionary phases separately. Results: For over 2.5 million stars we report mass, age, and distance estimates for each evolutionary phase and unimodal sub-PDF. We report Gaussian, skewed, Gaussian, truncated Gaussian, modified truncated exponential distribution or truncated Student's t-distribution functions to represent each sub-PDF, allowing us to reconstruct detailed PDFs. Comparisons with stellar parameter estimates from the literature show good agreement within uncertainties. Conclusions: We present UniDAM, the unified tool applicable to spectrophotometric data of different surveys, to obtain a homogenised set of stellar parameters. The unified tool and the tables with results are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/604/A108

The [Y/Mg] clock works for evolved solar metallicity stars

NASA Astrophysics Data System (ADS)

Slumstrup, D.; Grundahl, F.; Brogaard, K.; Thygesen, A. O.; Nissen, P. E.; Jessen-Hansen, J.; Van Eylen, V.; Pedersen, M. G.

2017-08-01

Aims: Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. Methods: High resolution and high signal-to-noise ratio (S/N) spectroscopic data of stars in the helium-core-burning phase have been obtained with the FIES spectrograph on the NOT 2.56 m telescope and the HIRES spectrograph on the Keck I 10 m telescope. They have been analyzed to determine the chemical abundances of four open clusters with close to solar metallicity; NGC 6811, NGC 6819, M 67 and NGC 188. The abundances are derived from equivalent widths of spectral lines using ATLAS9 model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Results from asteroseismology and binary studies were used as priors on the atmospheric parameters, where especially the log g is determined to much higher precision than what is possible with spectroscopy. Results: It is confirmed that the four open clusters are close to solar metallicity and they follow the [Y/Mg] vs. age trend previously found for solar twins. Conclusions: The [Y/Mg] vs. age clock also works for giant stars in the helium-core burning phase, which vastly increases the possibilities to estimate the age of stars not only in the solar neighborhood, but in large parts of the Galaxy, due to the brighter nature of evolved stars compared to dwarfs. Based on spectroscopic observations made with two telescopes: the Nordic Optical Telescope operated by NOTSA at the Observatorio del Roque de los Muchachos (La Palma, Spain) of the Instituto de Astrofísica de Canarias and the Keck I Telescope at the W.M. Keck Observatory (Mauna Kea, Hawaii, USA) operated by the California Institute of Technology, the University of California and the National Aeronautics and Space Administration.

Emission characteristics of refractory black carbon aerosols from fresh biomass burning: a perspective from laboratory experiments

NASA Astrophysics Data System (ADS)

Pan, Xiaole; Kanaya, Yugo; Taketani, Fumikazu; Miyakawa, Takuma; Inomata, Satoshi; Komazaki, Yuichi; Tanimoto, Hiroshi; Wang, Zhe; Uno, Itsushi; Wang, Zifa

2017-11-01

The emission characteristics of refractory black carbon (rBC) from biomass burning are essential information for numerical simulations of regional pollution and climate effects. We conducted combustion experiments in the laboratory to investigate the emission ratio and mixing state of rBC from the burning of wheat straw and rapeseed plants, which are the main crops cultivated in the Yangtze River Delta region of China. A single particle soot photometer (SP2) was used to measure rBC-containing particles at high temporal resolution and with high accuracy. The combustion state of each burning case was indicated by the modified combustion efficiency (MCE), which is calculated using the integrated enhancement of carbon dioxide and carbon monoxide concentrations relative to their background values. The mass size distribution of the rBC particles showed a lognormal shape with a mode mass equivalent diameter (MED) of 189 nm (ranging from 152 to 215 nm), assuming an rBC density of 1.8 g cm-3. rBC particles less than 80 nm in size (the lower detection limit of the SP2) accounted for ˜ 5 % of the total rBC mass, on average. The emission ratios, which are expressed as ΔrBC / ΔCO (Δ indicates the difference between the observed and background values), displayed a significant positive correlation with the MCE values and varied between 1.8 and 34 ng m-3 ppbv-1. Multi-peak fitting analysis of the delay time (Δt, or the time of occurrence of the scattering peak minus that of the incandescence peak) distribution showed that rBC-containing particles with rBC MED = 200 ± 10 nm displayed two peaks at Δt = 1.7 µs and Δt = 3.2 µs, which could be attributed to the contributions from both flaming and smoldering combustion in each burning case. Both the Δt values and the shell / core ratios of the rBC-containing particles clearly increased as the MCE decreased from 0.98 (smoldering-dominant combustion) to 0.86 (flaming-dominant combustion), implying the great importance of the rapid condensation of semi-volatile organics. This laboratory study found that the mixing state of rBC particles from biomass burning strongly depends on its combustion processes, and overall MCE should be taken carefully into consideration while the climate effect of rBC particles from open biomass burning is simulated.

Burn severity estimation using GeoEye imagery, object-based image analysis (OBIA), and Composite Burn Index (CBI) measurements

NASA Astrophysics Data System (ADS)

Dragozi, E.; Gitas, Ioannis Z.; Stavrakoudis, Dimitris G.; Minakou, C.

2015-06-01

Forest fires greatly influence the stability and functions of the forest ecosystems. The ever increasing need for accurate and detailed information regarding post-fire effects (burn severity) has led to several studies on the matter. In this study the combined use of Very High Resolution (VHR) satellite data (GeoEye), Objectbased image analysis (OBIA) and Composite Burn Index (CBI) measurements in estimating burn severity, at two different time points (2011 and 2012) is assessed. The accuracy of the produced maps was assessed and changes in burn severity between the two dates were detected using the post classification comparison approach. It was found that the produced burn severity map for 2011 was approximately 10% more accurate than that of 2012. This was mainly attributed to the increased heterogeneity of the study area in the second year, which led to an increased number of mixed class objects and consequently made it more difficult to spectrally discriminate between the severity classes. Following the post-classification analysis, the severity class changes were mainly attributed to the trees' ability to survive severe fire damage and sprout new leaves. Moreover, the results of the study suggest that when classifying CBI-based burn severity using VHR imagery it would be preferable to use images captured soon after the fire.

Application of Haddon's matrix in qualitative research methodology: an experience in burns epidemiology.

PubMed

Deljavan, Reza; Sadeghi-Bazargani, Homayoun; Fouladi, Nasrin; Arshi, Shahnam; Mohammadi, Reza

2012-01-01

Little has been done to investigate the application of injury specific qualitative research methods in the field of burn injuries. The aim of this study was to use an analytical tool (Haddon's matrix) through qualitative research methods to better understand people's perceptions about burn injuries. This study applied Haddon's matrix as a framework and an analytical tool for a qualitative research methodology in burn research. Both child and adult burn injury victims were enrolled into a qualitative study conducted using focus group discussion. Haddon's matrix was used to develop an interview guide and also through the analysis phase. The main analysis clusters were pre-event level/human (including risky behaviors, belief and cultural factors, and knowledge and education), pre-event level/object, pre-event phase/environment and event and post-event phase (including fire control, emergency scald and burn wound management, traditional remedies, medical consultation, and severity indicators). This research gave rise to results that are possibly useful both for future injury research and for designing burn injury prevention plans. Haddon's matrix is applicable in a qualitative research methodology both at data collection and data analysis phases. The study using Haddon's matrix through a qualitative research methodology yielded substantially rich information regarding burn injuries that may possibly be useful for prevention or future quantitative research.

Utility of Gram stain for the microbiological analysis of burn wound surfaces.

PubMed

Elsayed, Sameer; Gregson, Daniel B; Lloyd, Tracie; Crichton, Marilyn; Church, Deirdre L

2003-11-01

Surface swab cultures have attracted attention as a potential alternative to biopsy histology or quantitative culture methods for microbiological burn wound monitoring. To our knowledge, the utility of adding a Gram-stained slide in this context has not been evaluated previously. To determine the degree of correlation of Gram stain with culture for the microbiological analysis of burn wound surfaces. Prospective laboratory analysis. Urban health region/centralized diagnostic microbiology laboratory. Burn patients hospitalized in any Calgary Health Region burn center from November 2000 to September 2001. Gram stain plus culture of burn wound surface swab specimens obtained during routine dressing changes or based on clinical signs of infection. Degree of correlation (complete, high, partial, none), including weighted kappa statistic (kappa(w)), of Gram stain with culture based on quantitative microscopy and degree of culture growth. A total of 375 specimens from 50 burn patients were evaluated. Of these, 239 were negative by culture and Gram stain, 7 were positive by Gram stain only, 89 were positive by culture only, and 40 were positive by both methods. The degree of complete, high, partial, and no correlation of Gram stain with culture was 70.9% (266/375), 1.1% (4/375), 2.4% (9/375), and 25.6% (96/375), respectively. The degree of correlation for all 375 specimens, as expressed by the weighted kappa statistic, was found to be fair (kappa(w) = 0.32).Conclusion.-The Gram stain is not suitable for the microbiological analysis of burn wound surfaces.

Enhancing the clinical utility of the burn specific health scale-brief: not just for major burns.

PubMed

Finlay, V; Phillips, M; Wood, F; Hendrie, D; Allison, G T; Edgar, D

2014-03-01

Like many other Western burn services, the proportion of major to minor burns managed at Royal Perth Hospital (RPH) is in the order of 1:10. The Burn Specific Health Scale-Brief (BSHS-B) is an established measure of recovery after major burn, however its performance and validity in a population with a high volume of minor burns is uncertain. Utilizing the tool across burns of all sizes would be useful in service wide clinical practice. This study was designed to examine the reliability and validity of the BSHS-B across a sample of mostly minor burn patients. BSHS-B scores of patients, obtained between January 2006 and February 2013 and stored on a secure hospital database were collated and analyzed Cronbach's alpha, factor analysis, logistic regression and longitudinal regression were used to examine reliability and validity of the BSHS-B. Data from 927 burn patients (2031 surveys) with a mean % total burn surface area (TBSA) of 6.7 (SD 10.0) were available for analysis. The BSHS-B demonstrated excellent reliability with a Cronbach's alpha of 0.95. First and second order factor analyses reduced the 40 item scale to four domains: Work; Affect and Relations; Physical Function; Skin Involvement, as per the established construct. TBSA, length of stay and burn surgery all predicted burn specific health in the first three months of injury (p<0.001, p<0.001, p=0.03). BSHS-B whole scale and domain scores showed significant improvement over 24 months from burn (p<0.001). The results from this study show that the structure and performance of the BSHS-B in a burn population consisting of 90% minor burns is consistent with that demonstrated in major burns. The BSHS-B can be employed to track and predict recovery after burns of all sizes to assist the provision of targeted burn care. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Single mode, broad-waveguide ARROW-type semiconductor diode lasers

NASA Astrophysics Data System (ADS)

Al-Muhanna, Abdulrahman Ali

A broad transverse waveguide (low confinement) concept is used to achieve a record-high spatially incoherent cw output power of 11W for InGaAs active devices (λ = 0.97 μm) from 100μm wide-stripe and 2mm-long devices with low internal loss, α1 = 1cm-1, and high characteristic temperatures, T0 = 210K, and T1 = 1800K. A detailed above-threshold analysis reveals that reduction in gain spatial hole burning (GSHB) is possible in ARROW-type structures by using a low transverse confinement factor; consequently, a wider ARROW-core can be utilized. By incorporating both a broad-waveguide concept as well as an asymmetric structure in the transverse direction, and an ARROW-type structure in the lateral direction, a novel single-spatial mode diode laser with improved performance is obtained. Devices with low transverse confinement factor (Γ ~ 1%) and a core-region width of 7.8 μm achieved 510mW single-spatial mode pulsed output power (λ = 0.946 μm) with a full- width at half-maximum (FWHM) of the lateral far-field pattern of 4.7°.

Gas-core reactor power transient analysis

NASA Technical Reports Server (NTRS)

Kascak, A. F.

1972-01-01

The gas core reactor is a proposed device which features high temperatures. It has applications in high specific impulse space missions, and possibly in low thermal pollution MHD power plants. The nuclear fuel is a ball of uranium plasma radiating thermal photons as opposed to gamma rays. This thermal energy is picked up before it reaches the solid cavity liner by an inflowing seeded propellant stream and convected out through a rocket nozzle. A wall-burnout condition will exist if there is not enough flow of propellant to convect the energy back into the cavity. A reactor must therefore operate with a certain amount of excess propellant flow. Due to the thermal inertia of the flowing propellant, the reactor can undergo power transients in excess of the steady-state wall burnout power for short periods of time. The objective of this study was to determine how long the wall burnout power could be exceeded without burning out the cavity liner. The model used in the heat-transfer calculation was one-dimensional, and thermal radiation was assumed to be a diffusion process.

Towards more efficient burn care: Identifying factors associated with good quality of life post-burn.

PubMed

Finlay, V; Phillips, M; Allison, G T; Wood, F M; Ching, D; Wicaksono, D; Plowman, S; Hendrie, D; Edgar, D W

2015-11-01

As minor burn patients constitute the vast majority of a developed nation case-mix, streamlining care for this group can promote efficiency from a service-wide perspective. This study tested the hypothesis that a predictive nomogram model that estimates likelihood of good long-term quality of life (QoL) post-burn is a valid way to optimise patient selection and risk management when applying a streamlined model of care. A sample of 224 burn patients managed by the Burn Service of Western Australia who provided both short and long-term outcomes was used to estimate the probability of achieving a good QoL defined as 150 out of a possible 160 points on the Burn Specific Health Scale-Brief (BSHS-B) at least six months from injury. A multivariate logistic regression analysis produced a predictive model provisioned as a nomogram for clinical application. A second, independent cohort of consecutive patients (n=106) was used to validate the predictive merit of the nomogram. Male gender (p=0.02), conservative management (p=0.03), upper limb burn (p=0.04) and high BSHS-B score within one month of burn (p<0.001) were significant predictors of good outcome at six months and beyond. A Receiver Operating Curve (ROC) analysis demonstrated excellent (90%) accuracy overall. At 80% probability of good outcome, the false positive risk was 14%. The nomogram was validated by running a second ROC analysis of the model in an independent cohort. The analysis confirmed high (86%) overall accuracy of the model, the risk of false positive was reduced to 10% at a lower (70%) probability. This affirms the stability of the nomogram model in different patient groups over time. An investigation of the effect of missing data on sample selection determined that a greater proportion of younger patients with smaller TBSA burns were excluded due to loss to follow up. For clinicians managing comparable burn populations, the BSWA burns nomogram is an effective tool to assist the selection of patients to a streamlined care pathway with the aim of improving efficiency of service delivery. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

An Analysis Framework Using Satellite Remote Sensing to Understand Landscape Patterns of High Severity Burns from Wildfires in Coastal Woodlands of California and Italy

NASA Astrophysics Data System (ADS)

Potter, C. S.

2016-12-01

The central California coastal landscape has a history of frequent large wildfires that have threatened or destroyed many residential structures at the wildland interface. This study starts with the largest wildfires on the Central Coast over the past 30 years and analyzes the fraction and landscape patterns of high severity burned (HBS) areas from the Landsat-based Monitoring Trends in Burn Severity (MTBS) data base as a function of weather conditions and topographic variations. Results indicate that maximum temperatures at the time of fire and the previous 12 months of rainfall explained a significant portion of the variation in total area burned and the fraction of HBS area. Average patch size and aggregation metrics of HBS areas were included in the analysis framework. Within each burned area, the Landsat (30-meter resolution) differenced Normalized Burn Ratio (dNBR), a continuous index of vegetation burn severity, was correlated against slope, aspect, and elevation to better understand landscape level-controls over HBS patches. The Landsat dNBR analysis framework is being extended next to the island of Sardinia, Italy for a comparison of Mediterranean climates and wildfire patterns since the mid-1980s.

Mercury content of Illinois soils

USGS Publications Warehouse

Dreher, G.B.; Follmer, L.R.

2004-01-01

For a survey of Illinois soils, 101 cores had been collected and analyzed to determine the current and background elemental compositions of Illinois soils. Mercury and other elements were determined in six samples per core, including a surface sample from each core. The mean mercury content in the surface samples was 33 ?? 20 ??g/kg soil, and the background content was 20 ?? 9 ??g/kg. The most probable sources of mercury in these soils were the parent material, and wet and dry deposition of Hg0 and Hg2+ derived from coal-burning power plants, other industrial plants, and medical and municipal waste incinerators. Mercury-bearing sewage sludge or other fertilizers applied to agricultural fields could have been the local sources of mercury. Although the mercury content correlated with organic carbon content or clay content in individual cores, when all the data were considered, there was no strong correlation between mercury and either the organic carbon or the clay-size content.

Prescribed burning cost recovery analysis on nonindustrial private forestland in North Carolina

Treesearch

Ronald J. Myers; William Powell; Mark Megalos

2012-01-01

A statewide internal analysis of prescribed burning costs was conducted by the North Carolina Division of Forest Resources (NCDFR) in 2008 to examine the regional differences of site preparation and silvicultural burning costs, and to determine which components were most responsible for losses or gains. This study analyzed actual costs for 90 site preparation (2,559...

40 CFR 63.11211 - How do I demonstrate initial compliance with the emission limits?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Table 4 to this subpart, conducting a fuel analysis for each type of fuel burned in your boiler... evaluations according to § 63.11224. For affected boilers that burn a single type of fuel, you are exempted from the compliance requirements of conducting a fuel analysis for each type of fuel burned in your...

40 CFR 63.11211 - How do I demonstrate initial compliance with the emission limits?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Table 4 to this subpart, conducting a fuel analysis for each type of fuel burned in your boiler... evaluations according to § 63.11224. For affected boilers that burn a single type of fuel, you are exempted from the compliance requirements of conducting a fuel analysis for each type of fuel burned in your...

Development code for sensitivity and uncertainty analysis of input on the MCNPX for neutronic calculation in PWR core

NASA Astrophysics Data System (ADS)

Hartini, Entin; Andiwijayakusuma, Dinan

2014-09-01

This research was carried out on the development of code for uncertainty analysis is based on a statistical approach for assessing the uncertainty input parameters. In the butn-up calculation of fuel, uncertainty analysis performed for input parameters fuel density, coolant density and fuel temperature. This calculation is performed during irradiation using Monte Carlo N-Particle Transport. The Uncertainty method based on the probabilities density function. Development code is made in python script to do coupling with MCNPX for criticality and burn-up calculations. Simulation is done by modeling the geometry of PWR terrace, with MCNPX on the power 54 MW with fuel type UO2 pellets. The calculation is done by using the data library continuous energy cross-sections ENDF / B-VI. MCNPX requires nuclear data in ACE format. Development of interfaces for obtaining nuclear data in the form of ACE format of ENDF through special process NJOY calculation to temperature changes in a certain range.

Development code for sensitivity and uncertainty analysis of input on the MCNPX for neutronic calculation in PWR core

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartini, Entin, E-mail: entin@batan.go.id; Andiwijayakusuma, Dinan, E-mail: entin@batan.go.id

2014-09-30

This research was carried out on the development of code for uncertainty analysis is based on a statistical approach for assessing the uncertainty input parameters. In the butn-up calculation of fuel, uncertainty analysis performed for input parameters fuel density, coolant density and fuel temperature. This calculation is performed during irradiation using Monte Carlo N-Particle Transport. The Uncertainty method based on the probabilities density function. Development code is made in python script to do coupling with MCNPX for criticality and burn-up calculations. Simulation is done by modeling the geometry of PWR terrace, with MCNPX on the power 54 MW with fuelmore » type UO2 pellets. The calculation is done by using the data library continuous energy cross-sections ENDF / B-VI. MCNPX requires nuclear data in ACE format. Development of interfaces for obtaining nuclear data in the form of ACE format of ENDF through special process NJOY calculation to temperature changes in a certain range.« less

[Surgical treatment of burns : Special aspects of pediatric burns].

PubMed

Bührer, G; Beier, J P; Horch, R E; Arkudas, A

2017-05-01

Treatment of pediatric burn patients is very important because of the sheer frequency of burn wounds and the possible long-term ramifications. Extensive burns need special care and are treated in specialized burn centers. The goal of this work is to present current standards in burn therapy and important innovations in the treatment of burns in children so that the common and small area burn wounds and scalds in pediatric patients in day-to-day dermatological practice can be adequately treated. Analysis of current literature, discussion of reviews, incorporation of current guidelines. Burns in pediatric patients are common. Improvement of survival can be achieved by treatment in burn centers. The assessment of burn depth and area is an important factor for proper treatment. We give an overview for outpatient treatment of partial thickness burns. New methods may result in better long-term outcome. Adequate treatment of burn injuries considering current literature and guidelines improves patient outcome. Rational implementation of new methods is recommended.

Preserving self-concept in the burn survivors: a qualitative study.

PubMed

Zamanzadeh, Vahid; Valizadeh, Llila; Lotfi, Mojgan; Salehi, Feridoon

2015-01-01

Burn injury is a devastating experience affecting all aspects of a person's essence, including his/her identity and perception. These patients require complex cognitive efforts to redefine their identity to deal with difficult condition after burn injury and preserve self-concept. The experience of life after burn injury is generally a solitary one, closely related to the patients' cultural and religious context. Therefore, this study was conducted aiming at investigating burn patients' experiences regarding how to preserve self-concept in life after burn injury in Iran. This qualitative study was carried out using qualitative content analysis and in-depth unstructured interviews with 17 surviving burn subjects. During the qualitative content analysis process, the concept of "locating" as the essence of the participants' experience was extracted as follows: (A) self-exploration (exploring the changes in one's life), (B) others' exploration (exploring the changes in the life of family members and the relationship between self and others), (C) position evaluation (self-position analysis), and (D) self-concept preservation. The present study has developed new understandings of mental experiences of burn patients' self-concept by describing the concept of "self-locating". It helps us in classifying and understanding the concepts described in comprehensive theories developed in this area. They do this by focusing on what burn patients experience for choosing self-preservation strategies and having a meaningful life. The finding can be used as a conceptual framework for palliative care program in Iran.

Preserving Self-Concept in the Burn Survivors: A Qualitative Study

PubMed Central

Zamanzadeh, Vahid; Valizadeh, Llila; Lotfi, Mojgan; Salehi, Feridoon

2015-01-01

Background: Burn injury is a devastating experience affecting all aspects of a person's essence, including his/her identity and perception. These patients require complex cognitive efforts to redefine their identity to deal with difficult condition after burn injury and preserve self-concept. The experience of life after burn injury is generally a solitary one, closely related to the patients’ cultural and religious context. Therefore, this study was conducted aiming at investigating burn patients’ experiences regarding how to preserve self-concept in life after burn injury in Iran. Materials and Methods: This qualitative study was carried out using qualitative content analysis and in-depth unstructured interviews with 17 surviving burn subjects. Results: During the qualitative content analysis process, the concept of “locating” as the essence of the participants’ experience was extracted as follows: (A) self-exploration (exploring the changes in one's life), (B) others’ exploration (exploring the changes in the life of family members and the relationship between self and others), (C) position evaluation (self-position analysis), and (D) self-concept preservation. Conclusion: The present study has developed new understandings of mental experiences of burn patients’ self-concept by describing the concept of “self-locating”. It helps us in classifying and understanding the concepts described in comprehensive theories developed in this area. They do this by focusing on what burn patients experience for choosing self-preservation strategies and having a meaningful life. The finding can be used as a conceptual framework for palliative care program in Iran. PMID:26009672

Fire behavior simulation in Mediterranean forests using the minimum travel time algorithm

Treesearch

Kostas Kalabokidis; Palaiologos Palaiologou; Mark A. Finney

2014-01-01

Recent large wildfires in Greece exemplify the need for pre-fire burn probability assessment and possible landscape fire flow estimation to enhance fire planning and resource allocation. The Minimum Travel Time (MTT) algorithm, incorporated as FlamMap's version five module, provide valuable fire behavior functions, while enabling multi-core utilization for the...

Upregulation of MAOA in the hippocampus results in delayed depressive-like behaviors in burn mice.

PubMed

Wang, Zhen; Chen, Lu; Rong, Xinzhou; Wang, Xuemin

2017-04-14

To observe depressive-like behavior and hippocampus monoamine oxidase A (MAOA) changes in burned mice. We tested depression and anxiety like behaviors of burn C57 mice with the sucrose preference test, forced swimming test (FST), open field test and elevated plus maze test and then detected the MAOA content and MAOA gene transcriptional levels in the hippocampus with western blot analysis and real-time quantitative PCR analysis. We then sought to reverse depressive-like behavior of burned mice with an MAOA inhibitor. (1) Mice showed depressive and anxiety like behaviors one week after they were burned; (2) The content of MAOA in the hippocampus of burned mice was significantly higher than that in control mice (P<0.05); (3) MAOA gene transcription in the hippocampus of burned mice was significantly increased (MAOA mRNA was increased, P<0.05); (4) treatment with a MAOA inhibitor (phenelzine) significantly increased the sucrose preference rate and decreased FST immobility time in burned mice, and also decreased elevated expression of MAOA in the hippocampus of burned mice. Burned mice showed "delayed" depressive-like behavior combined with a degree of anxiety; this phenomenon is likely associated with the increase in MAOA expression in the hippocampus. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

The management of small area burns and unexpected illness after burn in children under five years of age - A costing study in the English healthcare setting.

PubMed

Kandiyali, R; Sarginson, J H; Hollén, L I; Spickett-Jones, F; Young, A E R

2018-02-01

The objective of this economic study was to evaluate the resource use and cost associated with the management of small area burns, including the additional costs associated with unexpected illness after burn in children of less than five years of age. This study was conducted as a secondary analysis of a multi-centre prospective observational cohort study investigating the physiological response to burns in children. 452 children were included in the economic analysis (median age=1.60years, 61.3% boys, median total burn surface area [TBSA]=1.00%) with a mean length of stay of 0.69 days. Of these children, 21.5% re-presented to medical care with an unexpected illness within fourteen days of injury. The cost of managing a burn of less than 10% TBSA in a child less than five years of age was £785. The additional cost associated with the management of illness after burn was £1381. A generalised linear regression model was used to determine the association between an unexpected illness after burn, presenting child characteristics and NHS cost. Our findings may be of value to those planning economic evaluations of novel technologies in burn care. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Application of thermal analysis to measure the spatial heterogeneity of organic matter degradation after wildfire: implications for post-fire rehabilitation treatments

NASA Astrophysics Data System (ADS)

Merino, Agustin; Fonturbel, M. Teresa; Vega, Jose A.

2015-04-01

Severe wildfires can cause drastic changes in SOM content and quality with important implications for soil conservation and global C balance. Soil heating usually leads to loss of the most labile SOM compounds (e.g. carbohydrates, lipids and peptides) and to generation of aromatic substances. However, these fire-related damages are not uniform over large areas, because of the spatial heterogeneity of different factors such as fire type and environmental conditions. Rapid diagnosis of soil burn severity is required to enable the design of emergency post-fire rehabilitation treatments. The study was conducted in soils from NW Spain, an Atlantic-climate zone that is particularly prone to wildfires. Intact soil cores (forest floor and uppermost mineral soil layer) were taken from a soil developed under granitic rock and subjected to experimental burning (in a bench positioned at the outlet of a wind tunnel). Soil temperature during fire was monitorised and five visual levels of soil burn severity (SBS) were recorded immediately after fire. Solid-state 13C CP-MAS NMR spectroscopy analyses were performed in an Agilent (Varian) VNMRS-500-WB spectrometer. The samples were analyzed by differential scanning calorimetry and thermogravimetry (TGA/DSC, Mettler-Toledo Intl. Inc.). The analyses were performed with 4 mg of samples placed in open aluminium pans under dry air (flow rate, 50 mL-1) and at a scanning rate of 10 °C min-1. The temperature ranged between 50 and 600 °C. In the organic layer, the temperature reached during fire influenced the formation and characteristics of charred material. These materials showed an increasing degree of carbonization/aromatization in relation to the increase of temperature during burning. Burning also led to compounds of higher thermal recalcitrance (increases in T50 values -the temperature at which 50% of the energy stored in SOM is released-). However, values recorded in some samples were lower than those measured in highly polycondensed aromatic compounds. In the mineral soil, large reductions in SOM content were found in both moderate and high SBS (up to 70 %), whereas important effects on SOM quality were only associated with high SBS. NMR analysis revealed these changes as losses of O-alkyl, alkyl and carboxylic structures and increases of the aromatic structures (up to 50 %). In both organic and mineral soils the DSC analysis revealed decreased combustion heat released up to 375 °C, and increased T50. Relationships between thermal properties and chemical-shift regions in the NMR helped provide a better understanding of SOM quality after wildfire. The results also show that thermal analysis can be used as a rapid tool to assess the different degrees of SOM degradation, in areas where the complex heterogeneity of the fire damage requires different emergency post-fire rehabilitation treatments.

The Enigmatic Bench Unit of Endeavour Crater Rim in Meridiani Planum, Mars

NASA Astrophysics Data System (ADS)

Ruff, S. W.

2013-12-01

For the first 2680 sols of its mission, the Mars Exploration Rover Opportunity traversed across essentially the same rocks: sulfur-rich sandstones known as the Burns formation. On August 8, 2011 Opportunity completed a ~21 km traverse from Victoria crater to the rim of the ~22 km diameter Endeavour crater where it crossed a slightly raised smooth bench unit that surrounds an interior core of higher standing and more rugged terrain on a rim segment named Cape York. As recognized by its distinctive morphologic character evident in orbital images, the inward sloping bench feature is found associated with portions of other segments of the discontinuous raised rim of Endeavour crater. Viewed by Opportunity, it appears as platy, fractured, relatively light-toned outcrop that is fine-grained, lacks hematite concretions and in places hosts veins of Ca- and S-rich composition, likely due to precipitation of gypsum in fractures that cut the bench unit (1). The bench outcrop target named Grasberg included a grind using the Rock Abrasion Tool (RAT) to obtain a cleaner surface for the Alpha Particle X-ray Spectrometer chemistry measurement compared with the initially investigated target named Deadwood. In addition to its greater strength than Burns formation as determined by the RAT grind operation, Grasberg and other examples of the bench unit have lower S, higher Cl and other elemental characteristics that depart from typical Burns formation. Thus the 'Grasberg unit' clearly represents a distinct rock type compared to the Meridiani plains. A second unit makes up the exposed core of the Cape York rim segment. Known as Shoemaker formation, it is composed of breccias that are recognized as a suevite deposit produced from the Endeavour impact event (1). The Shoemaker formation appears to be onlapped by the Grasberg unit with Burns formation onlapping it (1). However, a well-exposed section observed in a wedge-shaped fracture known as Whim Creek on the northeast portion of the Cape York bench clearly presents Grasberg rocks above Burns rocks. Erosion of a plunging synclinal form could explain this apparent inverted relationship, or it reveals that the Grasberg unit is younger than Burns formation. But this latter interpretation implies that Grasberg rocks, which have been observed only at the Endeavour rim, have been stripped off of Burns formation everywhere else. The Grasberg bench unit has recently been encountered in an isthmus setting between two low knobs of presumed Shoemaker formation called Nobbys Head and Sutherland Point just south of Cape York. The isthmus also presents Grasberg as topographically elevated above the Burns formation rocks. Despite its broad, smooth exposure, no remnants of Burns formation have been found on top of Grasberg at this location or anywhere on the Cape York bench. So the stratigraphic relationship between Grasberg and Burns rocks remains enigmatic. At the time of writing, Opportunity is at the edge of Solander Point, another bench feature on the northern tip of a rim segment known as Cape Tribulation. The erosional expression of this example appears different from those examined previously and perhaps offers the best chance to understand stratigraphic relationships. 1. S. W. Squyres et al., Ancient impact and aqueous processes at Endeavour Crater, Mars. Science 336, 570 (2012).

Comparing the reported burn conditions for different severity burns in porcine models: a systematic review.

PubMed

Andrews, Christine J; Cuttle, Leila

2017-12-01

There are many porcine burn models that create burns using different materials (e.g. metal, water) and different burn conditions (e.g. temperature and duration of exposure). This review aims to determine whether a pooled analysis of these studies can provide insight into the burn materials and conditions required to create burns of a specific severity. A systematic review of 42 porcine burn studies describing the depth of burn injury with histological evaluation is presented. Inclusion criteria included thermal burns, burns created with a novel method or material, histological evaluation within 7 days post-burn and method for depth of injury assessment specified. Conditions causing deep dermal scald burns compared to contact burns of equivalent severity were disparate, with lower temperatures and shorter durations reported for scald burns (83°C for 14 seconds) compared to contact burns (111°C for 23 seconds). A valuable archive of the different mechanisms and materials used for porcine burn models is presented to aid design and optimisation of future models. Significantly, this review demonstrates the effect of the mechanism of injury on burn severity and that caution is recommended when burn conditions established by porcine contact burn models are used by regulators to guide scald burn prevention strategies. © 2017 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Data summary of municipal solid waste management alternatives. Volume 3, Appendix A: Mass burn technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

This appendix on Mass Burn Technologies is the first in a series designed to identify, describe and assess the suitability of several currently or potentially available generic technologies for the management of municipal solid waste (MSW). These appendices, which cover eight core thermoconversion, bioconversion and recycling technologies, reflect public domain information gathered from many sources. Representative sources include: professional journal articles, conference proceedings, selected municipality solid waste management plans and subscription technology data bases. The information presented is intended to serve as background information that will facilitate the preparation of the technoeconomic and life cycle mass, energy and environmental analysesmore » that are being developed for each of the technologies. Mass burn has been and continues to be the predominant technology in Europe for the management of MSW. In the United States, the majority of the existing waste-to-energy projects utilize this technology and nearly 90 percent of all currently planned facilities have selected mass burn systems. Mass burning generally refers to the direct feeding and combustion of municipal solid waste in a furnace without any significant waste preprocessing. The only materials typically removed from the waste stream prior to combustion are large bulky objects and potentially hazardous or undesirable wastes. The technology has evolved over the last 100 or so years from simple incineration to the most highly developed and commercially proven process available for both reducing the volume of MSW and for recovering energy in the forms of steam and electricity. In general, mass burn plants are considered to operate reliably with high availability.« less

A Burke-Schumann analysis of diffusion-flame structures supported by a burning droplet

NASA Astrophysics Data System (ADS)

Nayagam, Vedha; Dietrich, Daniel L.; Williams, Forman A.

2017-07-01

A Burke-Schumann description of three different regimes of combustion of a fuel droplet in an oxidising atmosphere, namely the premixed-flame regime, the partial-burning regime and the diffusion-flame regime, is presented by treating the fuel and oxygen leakage fractions through the flame as known parameters. The analysis shows that the burning-rate constant, the flame-standoff ratio, and the flame temperature in these regimes can be obtained from the classical droplet-burning results by suitable definitions of an effective ambient oxygen mass fraction and an effective fuel concentration in the droplet interior. The results show that increasing oxygen leakage alone through the flame lowers both the droplet burning rate and the flame temperature, whereas leakage of fuel alone leaves the burning rate unaffected while reducing the flame temperature and moving the flame closer to the droplet surface. Solutions for the partial-burning regime are shown to exist only for a limited range of fuel and oxygen leakage fractions.

Application of the V-Gamma map to vehicle breakup analysis

NASA Technical Reports Server (NTRS)

Salama, Ahmed; McRonald, Angus; Ahmadi, Reza; LIng, Lisa; Accad, Elie; Kim, Alex

2003-01-01

The V-Gamma map consists of all possible pairs of speed and flight path angle at atmospheric entry interface for accidental Earth reentries resulting from steady misaligned burns, incomplete burns, or no burn.

Long Term Dynamic Stream Nitrate and Phosphate Changes Following Watershed Wildfires

NASA Technical Reports Server (NTRS)

Ambrosia, Vincent G.; Brass, James A.; Riggan, Philip J.; Ewing, Roy; Sebesta, Paul D.; Peterson, David L. (Technical Monitor)

1994-01-01

During and following the 1988 Yellowstone National Park wildfires, airborne remotely sensed data were collected in order to characterize various vegetative components, fire front movements and bum intensities. ER-2 derived Thematic Mapper Simulator (TMS) data were used in conjunction with water sampling and chemistry analysis to determine fire intensities in various watersheds and aquatic system condition changes. The airborne Daedalus multispectral TMS data allowed the characterization of various bum intensities in watersheds. Stream sampling was then conducted in those various burned watersheds to determine nitrate and phosphate concentration changes. Six stream watersheds were monitored for five years (1989-1993) during non-snow periods (May/June through September): Cache Creek (intensely burned), Blacktail Deer Creek (intensely burned), Snake River (moderately burned), Lamar River (mixed burning), Soda Butte Creek (lightly burned), and Amphitheatre Creek (unburned). One litre samples were collected from those streams with ISCO water samplers every 12 hours. The samples were removed every 14 days .(28 Samples), and water chemistry analysis was performed. Chemistry analysis indicated that nitrate and phosphate concentrations were elevated in moderately burned watersheds and significantly elevated in severely burned watersheds. The results during the five year study indicate that bum intensities regulate stream water nitrate and phosphate concentrations, and that remotely sensed data can be used effectively to predict watershed chemical changes which will affect aquatic conditions.

The 3D Death of a Massive Star

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2015-07-01

What happens at the very end of a massive star's life, just before its core's collapse? A group led by Sean Couch (California Institute of Technology and Michigan State University) claim to have carried out the first three-dimensional simulations of these final few minutes — revealing new clues about the factors that can lead a massive star to explode in a catastrophic supernova at the end of its life. A Giant Collapses In dying massive stars, in-falling matter bounces off the of collapsed core, creating a shock wave. If the shock wave loses too much energy as it expands into the star, it can stall out — but further energy input can revive it and result in a successful explosion of the star as a core-collapse supernova. In simulations of this process, however, theorists have trouble getting the stars to consistently explode: the shocks often stall out and fail to revive. Couch and his group suggest that one reason might be that these simulations usually start at core collapse assuming spherical symmetry of the progenitor star. Adding Turbulence Couch and his collaborators suspect that the key is in the final minutes just before the star collapses. Models that assume a spherically-symmetric star can't include the effects of convection as the final shell of silicon is burned around the core — and those effects might have a significant impact! To test this hypothesis, the group ran fully 3D simulations of the final three minutes of the life of a 15 solar-mass star, ending with core collapse, bounce, and shock-revival. The outcome was striking: the 3D modeling introduced powerful turbulent convection (with speeds of several hundred km/s!) in the last few minutes of silicon-shell burning. As a result, the initial structure and motions in the star just before core collapse were very different from those in core-collapse simulations that use spherically-symmetric initial conditions. The turbulence was then further amplified during collapse and formation of the shock, generating pressure that aided the shock expansion — which should ultimately help the star explode! The group cautions that their simulations are still very idealized, but these results clearly indicate that the 3D structure of massive stellar cores has an important impact on the core-collapse supernova mechanism. Citation Sean M. Couch et al. 2015 ApJ 808 L21 doi:10.1088/2041-8205/808/1/L21

Fuel Cycle Performance of Thermal Spectrum Small Modular Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worrall, Andrew; Todosow, Michael

2016-01-01

Small modular reactors may offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of small modular reactors on the nuclear fuel cycle and fuel cycle performance. The focus of this paper is on the fuel cycle impacts of light water small modular reactors in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy Office of Nuclear Energy Fuel Cycle Options Campaign. Challenges with small modular reactors include:more » increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burn-up in the reactor and the fuel cycle performance. This paper summarizes the results of an expert elicitation focused on developing a list of the factors relevant to small modular reactor fuel, core, and operation that will impact fuel cycle performance. Preliminary scoping analyses were performed using a regulatory-grade reactor core simulator. The hypothetical light water small modular reactor considered in these preliminary scoping studies is a cartridge type one-batch core with 4.9% enrichment. Some core parameters, such as the size of the reactor and general assembly layout, are similar to an example small modular reactor concept from industry. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burn-up of the reactor. Fuel cycle performance metrics for a small modular reactor are compared to a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. Metrics performance for a small modular reactor are degraded for mass of spent nuclear fuel and high level waste disposed, mass of depleted uranium disposed, land use per energy generated, and carbon emission per energy generated« less

Pediatric scalds: do cooking-related burns have a higher injury burden?

PubMed

Bachier, Marielena; Hammond, Sarah E; Williams, Regan; Jancelewicz, Timothy; Feliz, Alexander

2015-11-01

Pediatric scald burns result in frequent emergency room visits and hospitalizations. We investigated whether cooking-related burns produce greater morbidity requiring more extensive care than noncooking burns. We performed a 6-y review at our free-standing children's hospital. Children aged <18 y admitted for accidental scald burns were included. Demographics, injury pattern, treatment, and outcome (contractures and/or limited mobility and nonhealing and/or infected wounds) data were analyzed comparing cooking versus noncooking burns. The Mann-Whitney U test, a chi-square test, and the negative binomial were used to compare continuous, categorical, and count data between groups. Bivariate analysis was performed to identify risk factors among patients with adverse outcomes. We identified 308 patients; 262 (85%) cooking and 46 (15%) noncooking burns. Most patients were African-American males, with public insurance, and a median age of 2 y. Cooking burns preferentially occurred over the head, neck, and upper body; noncooking burns were distributed over the lower body (P < 0.02). Median total body surface area was equal for both groups (P > 0.11). In subgroup analysis, semisolid and grease burns resulted in increased rates of wound contractures and/or limited mobility when compared with noncooking burns (P = 0.05 and P = 0.008, respectively). Patients with complications were more likely to have third degree burns and required more consults, longer hospitalization, and more surgical debridements and clinic visits. Most accidental scald burns occurred in young children during food preparation. Greater long-term morbidity was found in patients with semisolid and grease burns. This subset of children has a higher injury burden and requires extensive care in the acute and long-term setting. Copyright © 2015 Elsevier Inc. All rights reserved.

40 CFR 63.7510 - What are my initial compliance requirements and by what date must I conduct them?

Code of Federal Regulations, 2011 CFR

2011-07-01

... subpart, conducting a fuel analysis for each type of fuel burned in your boiler or process heater... sources that burn a single type of fuel, you are exempted from the compliance requirements of conducting a fuel analysis for each type of fuel burned in your boiler or process heater according to § 63.7521 and...

40 CFR 63.7510 - What are my initial compliance requirements and by what date must I conduct them?

Code of Federal Regulations, 2012 CFR

2012-07-01

... subpart, conducting a fuel analysis for each type of fuel burned in your boiler or process heater... sources that burn a single type of fuel, you are exempted from the compliance requirements of conducting a fuel analysis for each type of fuel burned in your boiler or process heater according to § 63.7521 and...

An argument for weakly magnetized, slowly rotating progenitors of long gamma-ray bursts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreno Méndez, Enrique, E-mail: enriquemm@astro.unam.mx

2014-01-20

Using binary evolution with Case-C mass transfer, the spins of several black holes (BHs) in X-ray binaries (XBs) have been predicted and confirmed (three cases) by observations. The rotational energy of these BHs is sufficient to power up long gamma-ray bursts (GRBs) and hypernovae (HNe) and still leave a Kerr BH behind. However, strong magnetic fields and/or dynamo effects in the interior of such stars deplete their cores from angular momentum preventing the formation of collapsars. Thus, even though binaries can produce Kerr BHs, most of their rotation is acquired from the stellar mantle, with a long delay between BHmore » formation and spin up. Such binaries would not form GRBs. We study whether the conditions required to produce GRBs can be met by the progenitors of such BHs. Tidal-synchronization and Alfvén timescales are compared for magnetic fields of different intensities threading He stars. A search is made for a magnetic field range that allows tidal spin up all the way in to the stellar core but prevents its slow down during differential rotation phases. The energetics for producing a strong magnetic field during core collapse, which may allow for a GRB central engine, are also estimated. An observationally reasonable choice of parameters is found (B ≲ 10{sup 2} G threading a slowly rotating He star) that allows Fe cores to retain substantial angular momentum. Thus, the Case-C mass-transfer binary channel is capable of explaining long GRBs. However, the progenitors must have low initial spin and low internal magnetic field throughout their H-burning and He-burning phases.« less

Anthropogenic Influences on Estuarine Sedimentation in Salem Sound, MA

NASA Astrophysics Data System (ADS)

Kristiansen, E. R.; Hubeny, J. B.; Zhu, J.; Olsen, C. R.; Warren, B.

2010-12-01

The Salem Sound watershed (MA) historically has been a region of significant industrial activity. Two specific point sources for pollution in the region are the South Essex Sewerage District (SESD) wastewater treatment facility, and the Salem Harbor Power Station, a coal-burning power plant. This study tests the hypothesis that human impact on Salem Sound is preserved in the sediment record. A sediment core was taken near the location of the SESD outfall. This core was analyzed for content of organic matter via loss on ignition (LOI), as well as magnetic susceptibility. An age model was constructed using 137Cs and 210Pb. Below 31 cm (mid-nineteenth century), the core contains mean background values of 2.7% LOI and values increase above this depth. At 21cm, a rapid increase in organic matter concentration from 6.6% to 11.8% is observed. This depth corresponds to ~1905 which is contemporaneous with construction of the outfall pipe discharging raw wastewater. At a depth of 7 cm (mid 1970s), LOI values decrease from 11.7% to 9.3%. This shift is likely attributed to SESD beginning primary treatment in 1977. LOI values continue to drop at 2cm (late 1990s), from 7.8% to 6.3%, and remain at 6.1% to the modern surface, likely a result of SESD upgrading to secondary treatment in 1998. Magnetic susceptibility also shows variability down core that is likely attributed to human impact. At a depth of approximately 20cm susceptibility values start increasing from 4.2 SI units until they reach a peak at 15cm (8.8 SI units). This increase can be attributed to the industrial revolution and increased industrial activity in the area. A decrease in susceptibility is observed at 15cm to 11cm (5.6 SI units) that may be attributed to the Great Depression and less fossil fuels being burned due to the economic situation. At approximately 10cm and 8.0 SI units, an increasing trend is first observed. This trend continues up to the modern surface where it eventually reaches 19.9 SI units. This depth of 10cm coincides with the construction of the Salem Harbor Station in 1952, and the increasing trend can therefore most likely be explained by the proximal power plant burning coal.

1984–2010 trends in fire burn severity and area for the conterminous US

USGS Publications Warehouse

Picotte, Joshua J.; Peterson, Birgit E.; Meier, Gretchen; Howard, Stephen M.

2016-01-01

Burn severity products created by the Monitoring Trends in Burn Severity (MTBS) project were used to analyse historical trends in burn severity. Using a severity metric calculated by modelling the cumulative distribution of differenced Normalized Burn Ratio (dNBR) and Relativized dNBR (RdNBR) data, we examined burn area and burn severity of 4893 historical fires (1984–2010) distributed across the conterminous US (CONUS) and mapped by MTBS. Yearly mean burn severity values (weighted by area), maximum burn severity metric values, mean area of burn, maximum burn area and total burn area were evaluated within 27 US National Vegetation Classification macrogroups. Time series assessments of burned area and severity were performed using Mann–Kendall tests. Burned area and severity varied by vegetation classification, but most vegetation groups showed no detectable change during the 1984–2010 period. Of the 27 analysed vegetation groups, trend analysis revealed burned area increased in eight, and burn severity has increased in seven. This study suggests that burned area and severity, as measured by the severity metric based on dNBR or RdNBR, have not changed substantially for most vegetation groups evaluated within CONUS.

Role of nuclear grade graphite in controlling oxidation in modular HTGRs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Windes, Willaim; Strydom, G.; Kane, J.

2014-11-01

The passively safe High Temperature Gas-cooled Reactor (HTGR) design is one of the primary concepts considered for Generation IV and Small Modular Reactor (SMR) programs. The helium cooled, nuclear grade graphite moderated core achieves extremely high operating temperatures allowing either industrial process heat or electricity generation at high efficiencies. In addition to their neutron moderating properties, nuclear grade graphite core components provide excellent high temperature stability, thermal conductivity, and chemical compatibility with the high temperature nuclear fuel form. Graphite has been continuously used in nuclear reactors since the 1940’s and has performed remarkably well over a wide range of coremore » environments and operating conditions. Graphite moderated, gas-cooled reactor designs have been safely used for research and power production purposes in multiple countries since the inception of nuclear energy development. However, graphite is a carbonaceous material, and this has generated a persistent concern that the graphite components could actually burn during either normal or accident conditions [ , ]. The common assumption is that graphite, since it is ostensibly similar to charcoal and coal, will burn in a similar manner. While charcoal and coal may have the appearance of graphite, the internal microstructure and impurities within these carbonaceous materials are very different. Volatile species and trapped moisture provide a source of oxygen within coal and charcoal allowing them to burn. The fabrication process used to produce nuclear grade graphite eliminates these oxidation enhancing impurities, creating a dense, highly ordered form of carbon possessing high thermal diffusivity and strongly (covalently) bonded atoms.« less

An examination of the shrinking-core model of sub-micron aluminum combustion

NASA Astrophysics Data System (ADS)

Buckmaster, John; Jackson, Thomas L.

2013-04-01

We revisit the shrinking-core model of sub-micron aluminum combustion with particular attention to the mass flux balance at the reaction front which necessarily leads to a displacement velocity of the alumina shell surrounding the liquid aluminum. For the planar problem this displacement simply leads to an equal displacement of the entire alumina layer, and therefore a straightforward mathematical framework can be constructed. In this way we are able to construct a single curve which defines the burn time for arbitrary values of the diffusion coefficient of O atoms, the reaction rate, the characteristic length of the combustion field, and the O atom mass concentration within the alumina provided that it is much smaller than the aluminum density. This demonstrates a transition between a 'd 2-t' law for fast chemistry and a 'd-t' law for slow chemistry. For the spherical geometry, the one of physical interest, the outward displacement velocity creates not a simple displacement, but a stress field which, when examined within the framework of linear elasticity, strongly suggests the creation of internal cracking. We note that if the molten aluminum is pushed into these cracks by the high internal pressure characteristic of the stress field, its surface, where reaction occurs, could be fractal in nature and affect the fundamental nature of the burning law. Indeed, if this ingredient is added to the planar model, a single curve for the burn time can again be derived, and this describes a transition from a 'd 2-t' law to a 'd ν-t' law, where 0<ν<1.

In vitro burn model illustrating heat conduction patterns using compressed thermal papers.

PubMed

Lee, Jun Yong; Jung, Sung-No; Kwon, Ho

2015-01-01

To date, heat conduction from heat sources to tissue has been estimated by complex mathematical modeling. In the present study, we developed an intuitive in vitro skin burn model that illustrates heat conduction patterns inside the skin. This was composed of tightly compressed thermal papers with compression frames. Heat flow through the model left a trace by changing the color of thermal papers. These were digitized and three-dimensionally reconstituted to reproduce the heat conduction patterns in the skin. For standardization, we validated K91HG-CE thermal paper using a printout test and bivariate correlation analysis. We measured the papers' physical properties and calculated the estimated depth of heat conduction using Fourier's equation. Through contact burns of 5, 10, 15, 20, and 30 seconds on porcine skin and our burn model using a heated brass comb, and comparing the burn wound and heat conduction trace, we validated our model. The heat conduction pattern correlation analysis (intraclass correlation coefficient: 0.846, p < 0.001) and the heat conduction depth correlation analysis (intraclass correlation coefficient: 0.93, p < 0.001) showed statistically significant high correlations between the porcine burn wound and our model. Our model showed good correlation with porcine skin burn injury and replicated its heat conduction patterns. © 2014 by the Wound Healing Society.

Two Holocene paleofire records from Peten, Guatemala: Implications for natural fire regime and prehispanic Maya land use

USGS Publications Warehouse

Anderson, Lysanna; Wahl, David B.

2016-01-01

Although fire was arguably the primary tool used by the Maya to alter the landscape and extract resources, little attention has been paid to biomass burning in paleoenvironmental reconstructions from the Maya lowlands. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of macroscopic fossil charcoal recovered from lacustrine sediment cores. The records extend from the early Holocene, through the full arc of Maya prehistory, the Colonial, and post-Colonial periods (~ 9000 cal yr BP to the present). (Hereafter BP) The study sites, Lago Paixban and Lago Puerto Arturo, are located in northern Peten, Guatemala. Results provide the first quantitative analysis from the region demonstrating that frequent fires have occurred in the closed canopy forests since at least the early Holocene (~ 9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of agriculture around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Earliest Preclassic period suggest that land use strategies may have included intensive agriculture much earlier than previously thought. Preliminary results showing concentrations of soot/black-carbon during the middle and late Preclassic periods are lower than modern background values, providing intriguing implications regarding the efficiency of Maya fuel consumption.

Two Holocene paleofire records from Peten, Guatemala: Implications for natural fire regime and prehispanic Maya land use

NASA Astrophysics Data System (ADS)

Anderson, Lysanna; Wahl, David

2016-03-01

Although fire was arguably the primary tool used by the Maya to alter the landscape and extract resources, little attention has been paid to biomass burning in paleoenvironmental reconstructions from the Maya lowlands. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of macroscopic fossil charcoal recovered from lacustrine sediment cores. The records extend from the early Holocene, through the full arc of Maya prehistory, the Colonial, and post-Colonial periods ( 9000 cal yr BP to the present). (Hereafter BP) The study sites, Lago Paixban and Lago Puerto Arturo, are located in northern Peten, Guatemala. Results provide the first quantitative analysis from the region demonstrating that frequent fires have occurred in the closed canopy forests since at least the early Holocene ( 9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of agriculture around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Earliest Preclassic period suggest that land use strategies may have included intensive agriculture much earlier than previously thought. Preliminary results showing concentrations of soot/black-carbon during the middle and late Preclassic periods are lower than modern background values, providing intriguing implications regarding the efficiency of Maya fuel consumption.

Understanding Li enhancement in K giants and role of accurate parallaxes

NASA Astrophysics Data System (ADS)

Singh, Raghubar; Reddy, B. E.

2018-04-01

Our recent studies based on a large sample of K giants with Hipparcos parallaxes and spectroscopic analysis resulted more than a dozen new Li-rich K giants including few super Li-rich ones. Most of the Li-rich K giants including the new ones appear to occur at the luminosity bump in the HR diagram. However, one can't rule out the possibility of overlap with the clump region where core He-burning K giants reside post He-flash at the tip of RGB. It is important to distinguish field K giants of clump from the bump region in the HR diagram to understand clues for Li production in K giants. In this poster, we explore whether GAIA parallaxes improve to disentangle clump from bump region, more precisely.

The impact of socio-economic deprivation on burn injury: A nine-year retrospective study of 6441 patients.

PubMed

Marsden, N J; Battle, C E; Combellack, E J; Sabra, A; Morris, K; Dickson, W A; Whitaker, I S; Evans, P A

2016-03-01

Low socio-economic status is thought to be associated with increased burn risk, however the significance and generalisability across different populations and cultures has been questioned. A nine-year retrospective study of burn presentations to a large teaching hospital (2005-2014) was performed to investigate the association between socio-economic status and burns. Demographic and injury data was collected via the trust 'Information portal'. The Welsh Index of Multiple: Deprivation 2011 was used to score for socio-economic status. Chi-squared test and Odds Ratios were calculated and statistical significance defined as p<0.05 throughout. 6441 burns were identified, with 755 (11.7%) admitted. Overall incidence rates were the highest published in the UK (0.35/1000/year) with sub group analysis showing the highest rates in under fives and males. Significant relationships between both age and burn mechanism and gender and burn mechanism (p=0.0005) were identified. Scald (67.1%) was the most common mechanism with the upper limb (48%) most commonly burned. Chi square analysis demonstrated a significant relationship between socio-economic deprivation, age and burn incidence (p≤0.0005), with a disproportionately high number of burns in patients under the age of 16 in the most deprived quintile (OR 1.23; 95% CI 1.06-1.44). This study specifically highlights patients under the age of 16 living in poorer socio-economic areas as the most at risk of suffering burns receiving hospital attention. This study demonstrates burns as a significant public health issue, and the results should aid in designing specific burn prevention strategies to target high-risk groups. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Presupernova Evolution of Differentially Rotating Massive Stars Including Magnetic Fields

NASA Astrophysics Data System (ADS)

Heger, A.; Woosley, S. E.; Spruit, H. C.

2005-06-01

As a massive star evolves through multiple stages of nuclear burning on its way to becoming a supernova, a complex, differentially rotating structure is set up. Angular momentum is transported by a variety of classic instabilities and also by magnetic torques from fields generated by the differential rotation. We present the first stellar evolution calculations to follow the evolution of rotating massive stars including, at least approximately, all these effects, magnetic and nonmagnetic, from the zero-age main sequence until the onset of iron-core collapse. The evolution and action of the magnetic fields is as described by Spruit in 2002, and a range of uncertain parameters is explored. In general, we find that magnetic torques decrease the final rotation rate of the collapsing iron core by about a factor of 30-50 when compared with the nonmagnetic counterparts. Angular momentum in that part of the presupernova star destined to become a neutron star is an increasing function of main-sequence mass. That is, pulsars derived from more massive stars rotate faster and rotation plays a more important role in the star's explosion. The final angular momentum of the core has been determined-to within a factor of 2-by the time the star ignites carbon burning. For the lighter stars studied, around 15 Msolar, we predict pulsar periods at birth near 15 ms, though a factor of 2 range is easily tolerated by the uncertainties. Several mechanisms for additional braking in a young neutron star, especially by fallback, are explored.

A feasibility study of reactor-based deep-burn concepts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, T. K.; Taiwo, T. A.; Hill, R. N.

2005-09-16

A systematic assessment of the General Atomics (GA) proposed Deep-Burn concept based on the Modular Helium-Cooled Reactor design (DB-MHR) has been performed. Preliminary benchmarking of deterministic physics codes was done by comparing code results to those from MONTEBURNS (MCNP-ORIGEN) calculations. Detailed fuel cycle analyses were performed in order to provide an independent evaluation of the physics and transmutation performance of the one-pass and two-pass concepts. Key performance parameters such as transuranic consumption, reactor performance, and spent fuel characteristics were analyzed. This effort has been undertaken in close collaborations with the General Atomics design team and Brookhaven National Laboratory evaluation team.more » The study was performed primarily for a 600 MWt reference DB-MHR design having a power density of 4.7 MW/m{sup 3}. Based on parametric and sensitivity study, it was determined that the maximum burnup (TRU consumption) can be obtained using optimum values of 200 {micro}m and 20% for the fuel kernel diameter and fuel packing fraction, respectively. These values were retained for most of the one-pass and two-pass design calculations; variation to the packing fraction was necessary for the second stage of the two-pass concept. Using a four-batch fuel management scheme for the one-pass DB-MHR core, it was possible to obtain a TRU consumption of 58% and a cycle length of 286 EFPD. By increasing the core power to 800 MWt and the power density to 6.2 MW/m{sup 3}, it was possible to increase the TRU consumption to 60%, although the cycle length decreased by {approx}64 days. The higher TRU consumption (burnup) is due to the reduction of the in-core decay of fissile Pu-241 to Am-241 relative to fission, arising from the higher power density (specific power), which made the fuel more reactivity over time. It was also found that the TRU consumption can be improved by utilizing axial fuel shuffling or by operating with lower material temperatures (colder core). Results also showed that the transmutation performance of the one-pass deep-burn concept is sensitive to the initial TRU vector, primarily because longer cooling time reduces the fissile content (Pu-241 specifically.) With a cooling time of 5 years, the TRU consumption increases to 67%, while conversely, with 20-year cooling the TRU consumption is about 58%. For the two-pass DB-MHR (TRU recycling option), a fuel packing fraction of about 30% is required in the second pass (the recycled TRU). It was found that using a heterogeneous core (homogeneous fuel element) concept, the TRU consumption is dependent on the cooling interval before the 2nd pass, again due to Pu-241 decay during the time lag between the first pass fuel discharge and the second pass fuel charge. With a cooling interval of 7 years (5 and 2 years before and after reprocessing) a TRU consumption of 55% is obtained. With an assumed ''no cooling'' interval, the TRU consumption is 63%. By using a cylindrical core to reduce neutron leakage, TRU consumption of the case with 7-year cooling interval increases to 58%. For a two-pass concept using a heterogeneous fuel element (and homogeneous core) with first and second pass volume ratio of 2:1, the TRU consumption is 62.4%. Finally, the repository loading benefits arising from the deep-burn and Inert Matrix Fuel (IMF) concepts were estimated and compared, for the same initial TRU vector. The DB-MHR concept resulted in slightly higher TRU consumption and repository loading benefit compared to the IMF concept (58.1% versus 55.1% for TRU consumption and 2.0 versus 1.6 for estimated repository loading benefit).« less

The impacts of prescribed moorland burning on water colour and dissolved organic carbon: a critical synthesis.

PubMed

Holden, J; Chapman, P J; Palmer, S M; Kay, P; Grayson, R

2012-06-30

Discolouration of natural surface waters due to the humic component of dissolved organic carbon (DOC) is a costly problem for water supply companies. This paper reviews what is known about the impacts of prescribed moorland vegetation burning on water colour. Relevant research has taken place at three scales: laboratory experiments on peat cores, plot scale sampling of soil waters and catchment scale sampling of stream waters. While laboratory studies suggest burning increases colour production, the evidence from catchment and plot studies is contradictory. Plot studies suggest colour production may decrease or remain unchanged following burning although there is evidence for some transient changes. Catchment studies suggest prescribed moorland burning causes stream water colour to increase, although in most cases the evidence is not clear cut since most studies could not clearly disentangle the effects of burning from those of vegetation cover. The differences in findings between plot and catchment studies may be explained by: i) the short-term nature of some studies which do not measure long-term response and recovery times to burning; ii) the lack of colour measurements from shallow soil depths which contribute more to streamflow than soil water from deeper in the peat; and iii) the possibility of hydrological interactions occurring between different experimental plots at some sites. Additionally, the increase in recent patch burning in some catchments that has been statistically attributed by some authors to increases in stream water colour cannot be reconciled with theoretical calculations. When dilution with waters derived from other parts of the catchment are taken into account, large values of colour have to be theoretically derived from those recently burnt areas that occupy a small proportion of the catchment area in order to balance the change in stream water colour observed in recent years. Therefore, much further process-based work is required to properly investigate whether prescribed vegetation burning is a direct driver of enhanced colour and DOC in upland streams, rivers and lakes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Dynamic leaching studies of 48 MWd/kgU UO2 commercial spent nuclear fuel under oxic conditions

NASA Astrophysics Data System (ADS)

Serrano-Purroy, D.; Casas, I.; González-Robles, E.; Glatz, J. P.; Wegen, D. H.; Clarens, F.; Giménez, J.; de Pablo, J.; Martínez-Esparza, A.

2013-03-01

The leaching of a high-burn-up spent nuclear fuel (48 MWd/KgU) has been studied in a carbonate-containing solution and under oxic conditions using a Continuously Stirred Tank Flow-Through Reactor (CSTR). Two samples of the fuel, one prepared from the centre of the pellet (labelled CORE) and another one from the fuel pellet periphery, enriched with the so-called High Burn-Up Structure (HBS, labelled OUT) have been used.For uranium and actinides, the results showed that U, Np, Am and Cm gave very similar normalized dissolution rates, while Pu showed slower dissolution rates for both samples. In addition, dissolution rates were consistently two to four times lower for OUT sample compared to CORE sample.Considering the fission products release the main results are that Y, Tc, La and Nd dissolved very similar to uranium; while Cs, Sr, Mo and Rb have up to 10 times higher dissolution rates. Rh, Ru and Zr seemed to have lower dissolution rates than uranium. The lowest dissolution rates were found for OUT sample.Three different contributions were detected on uranium release, modelled and attributed to oxidation layer, fines and matrix release.

Theoretical Analysis on Marangoni-driven Cavity Formation in Ice during In Situ Burning of Oil Spills in Ice-infested Waters

NASA Astrophysics Data System (ADS)

Farmahini Farahani, H.; Jomaas, G.; Rangwala, A. S.

2017-12-01

In situ burning, intentional burning of discharged oil on the water surface, is a promising response method to oil spill accidents in the Arctic. However, burning of the oil adjacent to ice bodies creates a lateral cavity in the ice. As a result of the cavity formation the removal efficiency which is a key success criterion for in situ burning operation will decrease. The formation of lateral cavities are noticed recently and only a few experimental studies have addressed them. These experiments have shown lateral cavities with a length of <12 cm for 5 minutes burning of crude oil in laboratory. Our previous findings indicate the existence of a direct relation between the burning rate of the oil and penetration length in the ice. In addition, on the surface of the oil and near the ice the anchoring of the flame on the oil surface creates a severe horizontal temperature gradient which in turn generates a Marangoni flow from hot to cold regions. This is found to be the dominant heat transfer mechanism that is providing the heat for the ice to melt. Here, we introduce an order of magnitude analysis on the governing equations of the ice melting problem to estimate the penetration length of a burning oil near ice. This correlation incorporates the flame heat feedback with the surface flow driven by Marangoni convection. The melting energy continuity is also included in the analysis to complete the energy transfer cycle that leads to melting of the ice. The comparison between this correlation and the existing experimental data shows a very good agreement. Therefore, this correlation can be used to estimate the penetration length for burning of an actual spill and can be applied towards improved guidelines of burning adjacent to ice bodies, so as to enhance the chances for successful implantation of in situ burning.

Healthcare costs of burn patients from homes without fire sprinklers

PubMed Central

Banfield, Joanne; Rehou, Sarah; Gomez, Manuel; Redelmeier, Donald A.; Jeschke, Marc G.

2014-01-01

The treatment of burn injuries requires high-cost services for healthcare and society. Automatic fire sprinklers are a preventive measure that can decrease fire injuries, deaths, property damage and environmental toxins. This study’s aim was to conduct a cost-analysis of patients with burn or inhalation injuries due to residential fires, and to compare this to the cost of implementing residential automatic fire sprinklers. We conducted a cohort analysis of adult burn patients admitted to our provincial burn center (1995–2012). Patient demographics and injury characteristics were collected from medical records, and clinical and coroner databases. Resource costs included average cost per day at our intensive care and rehabilitation program, transportation, and property loss. During the study period there were 1,557 residential fire-related deaths province-wide and 1,139 patients were admitted to our provincial burn center due to a flame injury occurring at home. At our burn center, the average cost was CAN$84,678 per patient with a total cost of CAN$96,448,194. All resources totaled CAN$3,605,775,200. This study shows the considerable healthcare costs of burn patients from homes without fire sprinklers. PMID:25412056

On the origin of period changes in RR Lyrae stars

NASA Technical Reports Server (NTRS)

Renzini, A.; Sweigart, A. V.

1980-01-01

The observed period changes are explained with respect to the behavior of the semiconductive zone (SCZ) within the core of an RR Lyrae star. General consideration are given which suggest that the composition changes occuring within the SCZ during the horizontal-branch evolution result from many small mixing events, each of which slightly perturbs the pulsation period. Results indicate that small mixing events within the core of an RR Lyrae star can produce changes in the pulsation period comparable with those typically observed. It is further indicated that these mixing events together with the nuclear burning between them can produce period changes of both signs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mac Donald, Philip Elsworth; Buongiorno, Jacopo; Davis, Cliff Bybee

The purpose of this collaborative Idaho National Engineering and Environmental Laboratory (INEEL) and Massachusetts Institute of Technology (MIT) Laboratory Directed Research and Development (LDRD) project is to investigate the suitability of lead or lead-bismuth cooled fast reactors for producing low-cost electricity as well as for actinide burning. The goal is to identify and analyze the key technical issues in core neutronics, materials, thermal-hydraulics, fuels, and economics associated with the development of this reactor concept. Work has been accomplished in four major areas of research: core neutronic design, plant engineering, material compatibility studies, and coolant activation. The publications derived from workmore » on this project (since project inception) are listed in Appendix A.« less

Retrospective Analysis of Esophageal Heat Transfer for Active Temperature Management in Post-cardiac Arrest, Refractory Fever, and Burn Patients.

PubMed

Naiman, Melissa; Markota, Andrej; Hegazy, Ahmed; Dingley, John; Kulstad, Erik

2018-03-01

Core temperature management is an important aspect of critical care; preventing unintentional hypothermia, reducing fever, and inducing therapeutic hypothermia when appropriate are each tied to positive health outcomes. The purpose of this study is to evaluate the performance of a new temperature management device that uses the esophageal environment to conduct heat transfer. De-identified patient data were aggregated from three clinical sites where an esophageal heat transfer device (EHTD) was used to provide temperature management. The device was evaluated against temperature management guidelines and best practice recommendations, including performance during induction, maintenance, and cessation of therapy. Across all active cooling protocols, the average time-to-target was 2.37 h and the average maintenance phase was 22.4 h. Patients spent 94.9% of the maintenance phase within ±1.0°C and 67.2% within ±0.5°C (574 and 407 measurements, respectively, out of 605 total). For warming protocols, all of the patient temperature readings remained above 36°C throughout the surgical procedure (average 4.66 h). The esophageal heat transfer device met performance expectations across a range of temperature management applications in intensive care and burn units. Patients met and maintained temperature goals without any reported adverse events.

Acoustic emission strand burning technique for motor burning rate prediction

NASA Technical Reports Server (NTRS)

Christensen, W. N.

1978-01-01

An acoustic emission (AE) method is being used to measure the burning rate of solid propellant strands. This method has a precision of 0.5% and excellent burning rate correlation with both subscale and large rocket motors. The AE procedure burns the sample under water and measures the burning rate from the acoustic output. The acoustic signal provides a continuous readout during testing, which allows complete data analysis rather than the start-stop clockwires used by the conventional method. The AE method helps eliminate such problems as inhibiting the sample, pressure increase and temperature rise, during testing.

[Etiological analysis of subambient temperature burn in 351 cases of Hefei area].

PubMed

Shi, Jie; Qi, Weiwei; Xu, Qinglian; Zhou, Shunying; Wang, Guobao

2010-06-01

To study the preventive measure of the subambient temperature burn by analysing the pathogenesis feature. The clinical data were analysed from 351 cases of subambient temperature burn between February 2004 and February 2009, including age, sex, burn season, burn factors, burn position, burn area, burn degree, treatment way, and wound healing. Subambient temperature burn occurred in every age stage. The susceptible age stages included infant, children, and the elderly. Female patients were more than male patients. The common burn reasons were hot-water bottle burn, honey warm keeper burn, and heating device burn. The peak season was winter. Lower limb was the most common site of the subambient temperature burn. The deep II degree to III degree were the most common level, and the burn area was always small, often < or = 1% of total body surface area. Most of patients were treated with changing dressings at clinic and few patients needed hospitalization. Though the surface of wound could heal finally, and the wound healed well with no obvious scar in patients who received operation. Subambient temperature burn is the frequently encountered disease in winter. Use of the warming articles should be cautious, at the same time safety awareness should be strengthened so as to decrease the incidence rate of subambient temperature burn and the injury degree.

[Qualitative research on pain experiences of adult burn patients].

PubMed

Li, L; Pan, Q; Xu, L; Lin, R Q; Dai, J X; Chen, Z H

2018-03-20

Objective: To explore the pain experiences of adult burn patients so as to lay foundation for practical analgesic measures. Methods: Using phenomenological method in qualitative research, semi-structured interviews were conducted on 12 adult burn patients hospitalized in our burn units from May to November 2015, aiming at pain experiences from immediately after burns to 3 to 7 months after being discharged from hospital. Then the Colaizzi's analysis method was applied to analyze, induce, and refine themes of interview data. Results: After analysis, pain experiences of adult burn patients were generalized into 6 themes: deep pain experiences, heavy psychological burden, limited daily life, poor assessment and treatment of pain, different attributions of pain, and different ways of coping of pain. Conclusions: Burn pain brings harm to the patients' physiology, mentality, and daily life. Nevertheless, pain processing modes of medical staff and patients themselves are the key factors affecting patients' pain experiences. Therefore, according to the deficiency of current situation of pain management, the targeted analgesic intervention measures should be carried out from the perspectives of medical staff and patients.

Tracing anthropogenic impacts on nitrate deposition at Summit, Greenland from 1760 to 2002

NASA Astrophysics Data System (ADS)

Chellman, N.; Hastings, M. G.; McConnell, J. R.

2012-12-01

Nitrogen and oxygen isotopes of nitrate (NO3-) can be used to examine changes in nitrogen sources over time, as NO3- is the primary sink of nitrogen oxides (NOx) emissions from the atmosphere. This study presents a high-resolution, seasonal analysis of δ15N and δ18O of NO3- from an ice core collected at Summit, Greenland in 2010. The relationship between the δ15N record and major sources of NOx (fossil fuel combustion, biomass burning, and soil emission) was investigated using emissions data as well as isotopic, elemental, and molecular tracers, including tracers for oil and coal combustion (lead, sulfur, thallium, and cadmium) and biomass burning (black carbon and ammonium). The results show a marked negative trend in δ15N-NO3-, dropping 10‰ (vs. air N2) since pre-Industrial times from an average of 12.9‰ (1760-1810) to 2.9‰ (1952-2002), with the most rapid change occurring between 1960 and 1980. This overall trend can be attributed to significant changes in NOx sources since the Industrial Revolution. The relationships between the δ15N-NO3- signal and the tracers suggest that fossil fuel and soil NOx emissions have negative δ15N signatures, while biomass burning has a positive δ15N signature. The δ18O of NO3-, on the other hand, is not representative of source signals, but of the oxidation pathways in the atmosphere. The δ18O-NO3- ice core record displayed little change between pre- and post-Industrial eras, with only a slight increase of 2.6‰ from a pre-Industrial average of 73.2‰ (vs. VSMOW) to a post-Industrial average of 75.8‰. Importantly, the seasonality of the δ18O-NO3- signal, with higher values found in wintertime snow and lower values in summer, did not change throughout the record. The lack of any trend in the δ18O-NO3- signal is expected because seasonal photochemistry, the driving force of the seasonal δ18O signal, has not changed markedly during the past 250 years. In summary, the data from this study show that investigation of the isotopes of nitrate can help in understanding anthropogenic influence on NOx emissions in modern times. δ15N of nitrate vs. time. Summer (red) and winter (blue) δ15N values overlaid on complete record (grey). The record has a distinct negative trend, dropping 10‰ since pre-Industrial times. This negative trend is attributed to rapidly changing NOx emissions from fossil fuel combustion, soil emissions, and biomass burning.

Improving burn care and preventing burns by establishing a burn database in Ukraine.

PubMed

Fuzaylov, Gennadiy; Murthy, Sushila; Dunaev, Alexander; Savchyn, Vasyl; Knittel, Justin; Zabolotina, Olga; Dylewski, Maggie L; Driscoll, Daniel N

2014-08-01

Burns are a challenge for trauma care and a contribution to the surgical burden. The former Soviet republic of Ukraine has a foundation for burn care; however data concerning burns in Ukraine has historically been scant. The objective of this paper was to compare a new burn database to identify problems and implement improvements in burn care and prevention in this country. Retrospective analyses of demographic and clinical data of burn patients including Tukey's post hoc test, analysis of variance, and chi square analyses, and Fisher's exact test were used. Data were compared to the American Burn Association (ABA) burn repository. This study included 1752 thermally injured patients treated in 20 hospitals including Specialized Burn Unit in Municipal Hospital #8 Lviv, Lviv province in Ukraine. Scald burns were the primary etiology of burns injuries (70%) and burns were more common among children less than five years of age (34%). Length of stay, mechanical ventilation use, infection rates, and morbidity increased with greater burn size. Mortality was significantly related to burn size, inhalation injury, age, and length of stay. Wound infections were associated with burn size and older age. Compared to ABA data, Ukrainian patients had double the length of stay and a higher rate of wound infections (16% vs. 2.4%). We created one of the first burn databases from a region of the former Soviet Union in an effort to bring attention to burn injury and improve burn care. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Code dependencies of pre-supernova evolution and nucleosynthesis in massive stars: evolution to the end of core helium burning

DOE PAGES

Jones, S.; Hirschi, R.; Pignatari, M.; ...

2015-01-15

We present a comparison of 15M ⊙ , 20M ⊙ and 25M ⊙ stellar models from three different codes|GENEC, KEPLER and MESA|and their nucleosynthetic yields. The models are calculated from the main sequence up to the pre-supernova (pre-SN) stage and do not include rotation. The GENEC and KEPLER models hold physics assumptions that are characteristic of the two codes. The MESA code is generally more flexible; overshooting of the convective core during the hydrogen and helium burning phases in MESA is chosen such that the CO core masses are consistent with those in the GENEC models. Full nucleosynthesis calculations aremore » performed for all models using the NuGrid post-processing tool MPPNP and the key energy-generating nuclear reaction rates are the same for all codes. We are thus able to highlight the key diferences between the models that are caused by the contrasting physics assumptions and numerical implementations of the three codes. A reasonable agreement is found between the surface abundances predicted by the models computed using the different codes, with GENEC exhibiting the strongest enrichment of H-burning products and KEPLER exhibiting the weakest. There are large variations in both the structure and composition of the models—the 15M ⊙ and 20M ⊙ in particular—at the pre-SN stage from code to code caused primarily by convective shell merging during the advanced stages. For example the C-shell abundances of O, Ne and Mg predicted by the three codes span one order of magnitude in the 15M ⊙ models. For the alpha elements between Si and Fe the differences are even larger. The s-process abundances in the C shell are modified by the merging of convective shells; the modification is strongest in the 15M ⊙ model in which the C-shell material is exposed to O-burning temperatures and the γ -process is activated. The variation in the s-process abundances across the codes is smallest in the 25M ⊙ models, where it is comparable to the impact of nuclear reaction rate uncertainties. In general the differences in the results from the three codes are due to their contrasting physics assumptions (e.g. prescriptions for mass loss and convection). The broadly similar evolution of the 25M ⊙ models gives us reassurance that different stellar evolution codes do produce similar results. For the 15M ⊙ and 20M ⊙ models, however, the different input physics and the interplay between the various convective zones lead to important differences in both the pre-supernova structure and nucleosynthesis predicted by the three codes. For the KEPLER models the core masses are different and therefore an exact match could not be expected.« less

Predictive Value of IL-8 for Sepsis and Severe Infections after Burn Injury - A Clinical Study

PubMed Central

Kraft, Robert; Herndon, David N; Finnerty, Celeste C; Cox, Robert A; Song, Juquan; Jeschke, Marc G

2014-01-01

The inflammatory response induced by burn injury contributes to increased incidence of infections, sepsis, organ failure, and mortality. Thus, monitoring post-burn inflammation is of paramount importance but so far there are no reliable biomarkers available to monitor and/or predict infectious complications after burn. As IL-8 is a major mediator for inflammatory responses, the aim of our study was to determine whether IL-8 expression can be used to predict post-burn sepsis, infections, and mortality other outcomes post-burn. Plasma cytokines, acute phase proteins, constitutive proteins, and hormones were analyzed during the first 60 days post injury from 468 pediatric burn patients. Demographics and clinical outcome variables (length of stay, infection, sepsis, multiorgan failure (MOF), and mortality were recorded. A cut-off level for IL-8 was determined using receiver operating characteristic (ROC) analysis. Statistical significance is set at (p<0.05). ROC analysis identified a cut-off level of 234 pg/ml for IL-8 for survival. Patients were grouped according to their average IL-8 levels relative to this cut off and stratified into high (H) (n=133) and low (L) (n=335) groups. In the L group, regression analysis revealed a significant predictive value of IL-8 to percent of total body surface area (TBSA) burned and incidence of MOF (p<0.001). In the H group IL-8 levels were able to predict sepsis (p<0.002). In the H group, elevated IL-8 was associated with increased inflammatory and acute phase responses compared to the L group (p<0.05). High levels of IL-8 correlated with increased MOF, sepsis, and mortality. These data suggest that serum levels of IL-8 may be a valid biomarker for monitoring sepsis, infections, and mortality in burn patients. PMID:25514427

Adult survivors' lived experience of burns and post-burn health: A qualitative analysis.

PubMed

Abrams, Thereasa E; Ogletree, Roberta J; Ratnapradipa, Dhitinut; Neumeister, Michael W

2016-02-01

The individual implications of major burns are likely to affect the full spectrum of patients' physical, emotional, psychological, social, environmental, spiritual and vocational health. Yet, not all of the post-burn health implications are inevitably negative. Utilizing a qualitative approach, this heuristic phenomenological study explores the experiences and perceptions early (ages 18-35) and midlife (ages 36-64) adults providing insight for how participants perceived their burns in relationship to their post-burn health. Participants were interviewed using semi-structured interview questions framed around seven domains of health. Interview recordings were transcribed verbatim then coded line by line, identifying dominant categories related to health. Categories were analyzed identifying shared themes among the study sample. Participants were Caucasian, seven males and one female. Mean age at time of interviews was 54.38 and 42.38 at time of burns. Mean time since burns occurred was 9.38 years with a minimum of (20%) total body surface area (TBSA) burns. Qualitative content analysis rendered three emergent health-related categories and associated themes that represented shared meanings within the participant sample. The category of "Physical Health" reflected the theme physical limitations, pain and sensitivity to temperature. Within the category of "Intellectual Health" were themes of insight, goal setting and self-efficacy, optimism and humor and within "Emotional Health" were the themes empathy and gratitude. By exploring subjective experiences and perceptions of health shared through dialog with experienced burned persons, there are opportunities to develop a more complete picture of how holistic health may be affected by major burns that in turn could support future long-term rehabilitative trajectories of early and midlife adult burn patients. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Severity of burn and its related factors: A study from the developing country Pakistan.

PubMed

Adil, Syed Omair; Nisar, Nighat; Ehmer-Al-Ibran; Shafique, Kashif; Baig-Ansari, Naila

2016-06-01

Burns are leading cause of fatal injuries and major cause of morbidity and mortality in developing countries. The major obstacle in controlling severity is factors related to burn. This study determines frequency of burns and the factors related to it in Karachi, Pakistan. A cross-sectional study was conducted and 384 hospitalized adult patients with burns were consecutively interviewed during August 2013 to February 2014. Information was collected on socio-demographic profile, intent of burn, severity of burn, health hazards, physical and psychological characteristics. TBSA burn of >15% was considered as higher severity of burn. Higher severity of burns was found in 76.3% patients. Multivariate analysis showed that higher severity of burns were significantly associated with age less than 25 years (OR 2.7, 95% CI 1.5-4.9), never had been to school (OR 3.1, 95% CI 1.7-5.9) and intentional burn (OR 20.6, 95% CI 5.0-84.9). Majority of patients had higher severity of burn. The intent of injury was intentional, age less than 25 years and no schooling were found significantly associated with higher severity of burns. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Burns education for non-burn specialist clinicians in Western Australia.

PubMed

McWilliams, Tania; Hendricks, Joyce; Twigg, Di; Wood, Fiona

2015-03-01

Burn patients often receive their initial care by non-burn specialist clinicians, with increasingly collaborative burn models of care. The provision of relevant and accessible education for these clinicians is therefore vital for optimal patient care. A two phase design was used. A state-wide survey of multidisciplinary non-burn specialist clinicians throughout Western Australia identified learning needs related to paediatric burn care. A targeted education programme was developed and delivered live via videoconference. Pre-post-test analysis evaluated changes in knowledge as a result of attendance at each education session. Non-burn specialist clinicians identified numerous areas of burn care relevant to their practice. Statistically significant differences between perceived relevance of care and confidence in care provision were reported for aspects of acute burn care. Following attendance at the education sessions, statistically significant increases in knowledge were noted for most areas of acute burn care. Identification of learning needs facilitated the development of a targeted education programme for non-burn specialist clinicians. Increased non-burn specialist clinician knowledge following attendance at most education sessions supports the use of videoconferencing as an acceptable and effective method of delivering burns education in Western Australia. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

An unsuspected cause of meal-time morbidity: instant noodle scald burns.

PubMed

Koltz, Peter F; Wasicek, Philip; Mays, Chester; Bell, Derek E

2013-01-01

Observational analysis revealed a concerning frequency of scald burns secondary to instant noodles. A literature review reveals studies with small sample sizes of pediatric populations and analysis of container engineering. The adult cohort, treatments, and short-term outcomes have been neglected. Considering these deficiencies, we reviewed our institution's experience with burns secondary to instant noodles. Patient encounters due to instant noodle burns from January 1, 2007, through May 15, 2011, were reviewed. Demographics, burn characteristics, treatment, length of stay, number of operative interventions, and complications were analyzed. Eight hundred fifty-two patients were seen (460 were admitted) for scald burns of all pathogenesis. Of these, 121 (14%) were seen for burns secondary to noodles (63 men and 58 women). Of these, 48 were older than age 4 (group 1), and 73 were younger than age 4 (group 2). TBSA was 2.34 in group 1 and 1.64 in group 2 (P = .04). The most commonly burned areas in group 1 were extremities (n = 43) and in group 2 were chest (n = 32) and extremities (n = 31). Seven patients in group 1 and two patients in group 2 required operative intervention. Length of stay in groups 1 and 2 were 3.5 and 6 days, respectively. Noodle scald burns cause morbidity at all ages. Pediatric burns due to noodles are frequently managed conservatively but more often necessitate inpatient treatment. The nonpediatric population has larger TBSA and requires more frequent operative intervention. The morbidity of noodle burns is significant. Increased public education and container re-engineering is warranted.

BurnCase 3D software validation study: Burn size measurement accuracy and inter-rater reliability.

PubMed

Parvizi, Daryousch; Giretzlehner, Michael; Wurzer, Paul; Klein, Limor Dinur; Shoham, Yaron; Bohanon, Fredrick J; Haller, Herbert L; Tuca, Alexandru; Branski, Ludwik K; Lumenta, David B; Herndon, David N; Kamolz, Lars-P

2016-03-01

The aim of this study was to compare the accuracy of burn size estimation using the computer-assisted software BurnCase 3D (RISC Software GmbH, Hagenberg, Austria) with that using a 2D scan, considered to be the actual burn size. Thirty artificial burn areas were pre planned and prepared on three mannequins (one child, one female, and one male). Five trained physicians (raters) were asked to assess the size of all wound areas using BurnCase 3D software. The results were then compared with the real wound areas, as determined by 2D planimetry imaging. To examine inter-rater reliability, we performed an intraclass correlation analysis with a 95% confidence interval. The mean wound area estimations of the five raters using BurnCase 3D were in total 20.7±0.9% for the child, 27.2±1.5% for the female and 16.5±0.1% for the male mannequin. Our analysis showed relative overestimations of 0.4%, 2.8% and 1.5% for the child, female and male mannequins respectively, compared to the 2D scan. The intraclass correlation between the single raters for mean percentage of the artificial burn areas was 98.6%. There was also a high intraclass correlation between the single raters and the 2D Scan visible. BurnCase 3D is a valid and reliable tool for the determination of total body surface area burned in standard models. Further clinical studies including different pediatric and overweight adult mannequins are warranted. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

The Clinical Significance of the MIF Homolog D-Dopachrome Tautomerase (MIF-2) and its Circulating Receptor (sCD74) in Burn Injury

PubMed Central

Kim, Bong-Sung; Stoppe, Christian; Grieb, Gerrit; Leng, Lin; Sauler, Maor; Assis, David; Simons, David; Boecker, Arne Hendrick; Schulte, Wibke; Piecychna, Marta; Hager, Stephan; Bernhagen, Jürgen; Pallua, Norbert; Bucala, Richard

2016-01-01

Background We reported earlier that the cytokine macrophage migration inhibitory factor (MIF) is a potential biomarker in burn injury. In the present study, we investigated the clinical significance in severely burned patients of expression levels the newly discovered MIF family member D-dopachrome tautomerase (DDT or MIF-2) and their common soluble receptor CD74 (sCD74). Methods DDT and sCD74 serum levels were measured 20 severely burned patients and 20 controls. Serum levels were correlated to the abbreviated burn severity index (ABSI) and TBSA followed by receiver operating characteristic (ROC) analysis. Data were supported by gene expression dataset analysis of 31 burn patients and 28 healthy controls. Results CD74 and DDT were increased in burn patients. Furthermore, CD74 and DDT also were elevated in septic non-survivors when compared to survivors. Serum levels of DDT showed a positive correlation with the ABSI and TBSA in the early stage after burn injury, and the predictive character of DDT was strongest at 24 hrs. Serum levels of CD74 only correlated with the ABSI five days post-injury. Conclusions DDT may assist in the monitoring of clinical outcome and prediction of sepsis during the early post-burn period. sCD74 and MIF, by contrast, have limited value as an early predictor of death due to their delayed response to burn injury. PMID:27209369

Monitoring a boreal wildfire using multi-temporal Radarsat-1 intensity and coherence images

USGS Publications Warehouse

Rykhus, Russell P.; Lu, Zhong

2011-01-01

Twenty-five C-band Radarsat-1 synthetic aperture radar (SAR) images acquired from the summer of 2002 to the summer of 2005 are used to map a 2003 boreal wildfire (B346) in the Yukon Flats National Wildlife Refuge, Alaska under conditions of near-persistent cloud cover. Our analysis is primarily based on the 15 SAR scenes acquired during arctic growing seasons. The Radarsat-1 intensity data are used to map the onset and progression of the fire, and interferometric coherence images are used to qualify burn severity and monitor post-fire recovery. We base our analysis of the fire on three test sites, two from within the fire and one unburned site. The B346 fire increased backscattered intensity values for the two burn study sites by approximately 5–6 dB and substantially reduced coherence from background levels of approximately 0.8 in unburned background forested areas to approximately 0.2 in the burned area. Using ancillary vegetation information from the National Land Cover Database (NLCD) and information on burn severity from Normalized Burn Ratio (NBR) data, we conclude that burn site 2 was more severely burned than burn site 1 and that C-band interferometric coherence data are useful for mapping landscape changes due to fire. Differences in burn severity and topography are determined to be the likely reasons for the observed differences in post-fire intensity and coherence trends between burn sites.

Accident analysis of heavy water cooled thorium breeder reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yulianti, Yanti; Su’ud, Zaki; Takaki, Naoyuki

2015-04-16

Thorium has lately attracted considerable attention because it is accumulating as a by-product of large scale rare earth mining. The objective of research is to analyze transient behavior of a heavy water cooled thorium breeder that is designed by Tokai University and Tokyo Institute of Technology. That is oxide fueled, PWR type reactor with heavy water as primary coolant. An example of the optimized core has relatively small moderator to fuel volume ratio (MFR) of 0.6 and the characteristics of the core are burn-up of 67 GWd/t, breeding ratio of 1.08, burn-up reactivity loss during cycles of < 0.2% dk/k,more » and negative coolant reactivity coefficient. One of the nuclear reactor accidents types examined here is Unprotected Transient over Power (UTOP) due to withdrawing of the control rod that result in the positive reactivity insertion so that the reactor power will increase rapidly. Another accident type is Unprotected Loss of Flow (ULOF) that caused by failure of coolant pumps. To analyze the reactor accidents, neutron distribution calculation in the nuclear reactor is the most important factor. The best expression for the neutron distribution is the Boltzmann transport equation. However, solving this equation is very difficult so that the space-time diffusion equation is commonly used. Usually, space-time diffusion equation is solved by employing a point kinetics approach. However, this approach is less accurate for a spatially heterogeneous nuclear reactor and the nuclear reactor with quite large reactivity input. Direct method is therefore used to solve space-time diffusion equation which consider spatial factor in detail during nuclear reactor accident simulation. Set of equations that obtained from full implicit finite-difference method is solved by using iterative methods. The indication of UTOP accident is decreasing macroscopic absorption cross-section that results large external reactivity, and ULOF accident is indicated by decreasing coolant flow. The power reactor has a peak value before reactor has new balance condition. The analysis showed that temperatures of fuel and claddings during accident are still below limitations which are in secure condition.« less

Accident analysis of heavy water cooled thorium breeder reactor

NASA Astrophysics Data System (ADS)

Yulianti, Yanti; Su'ud, Zaki; Takaki, Naoyuki

2015-04-01

Thorium has lately attracted considerable attention because it is accumulating as a by-product of large scale rare earth mining. The objective of research is to analyze transient behavior of a heavy water cooled thorium breeder that is designed by Tokai University and Tokyo Institute of Technology. That is oxide fueled, PWR type reactor with heavy water as primary coolant. An example of the optimized core has relatively small moderator to fuel volume ratio (MFR) of 0.6 and the characteristics of the core are burn-up of 67 GWd/t, breeding ratio of 1.08, burn-up reactivity loss during cycles of < 0.2% dk/k, and negative coolant reactivity coefficient. One of the nuclear reactor accidents types examined here is Unprotected Transient over Power (UTOP) due to withdrawing of the control rod that result in the positive reactivity insertion so that the reactor power will increase rapidly. Another accident type is Unprotected Loss of Flow (ULOF) that caused by failure of coolant pumps. To analyze the reactor accidents, neutron distribution calculation in the nuclear reactor is the most important factor. The best expression for the neutron distribution is the Boltzmann transport equation. However, solving this equation is very difficult so that the space-time diffusion equation is commonly used. Usually, space-time diffusion equation is solved by employing a point kinetics approach. However, this approach is less accurate for a spatially heterogeneous nuclear reactor and the nuclear reactor with quite large reactivity input. Direct method is therefore used to solve space-time diffusion equation which consider spatial factor in detail during nuclear reactor accident simulation. Set of equations that obtained from full implicit finite-difference method is solved by using iterative methods. The indication of UTOP accident is decreasing macroscopic absorption cross-section that results large external reactivity, and ULOF accident is indicated by decreasing coolant flow. The power reactor has a peak value before reactor has new balance condition. The analysis showed that temperatures of fuel and claddings during accident are still below limitations which are in secure condition.

Management of the high-order mode content in large (40 microm) core photonic bandgap Bragg fiber laser.

PubMed

Gaponov, D A; Février, S; Devautour, M; Roy, P; Likhachev, M E; Aleshkina, S S; Salganskii, M Y; Yashkov, M V; Guryanov, A N

2010-07-01

Very large-mode-area Yb(3+)-doped single-mode photonic bandgap (PBG) Bragg fiber oscillators are considered. The transverse hole-burning effect is numerically modeled, which helps properly design the PBG cladding and the Yb(3+)-doped region for the high-order mode content to be carefully controlled. A ratio of the Yb(3+)-doped region diameter to the overall core diameter of 40% allows for single-mode emission, even for small spool diameters of 15 cm. Such a fiber was manufactured and subsequently used as the core element of a cw oscillator. Very good beam quality parameter M(2)=1.12 and slope efficiency of 80% were measured. Insensitivity to bending, exemplified by the absence of temporal drift of the beam, was demonstrated for curvature diameter as small as 15 cm.

Verified Centers, Nonverified Centers or Other Facilities: A National Analysis of Burn Patient Treatment Location

PubMed Central

Zonies, David; Mack, Christopher; Kramer, Bradley; Rivara, Frederick; Klein, Matthew

2009-01-01

Background Although comprehensive burn care requires significant resources, patients may be treated at verified burn centers, non-verified burn centers, or other facilities due to a variety of factors. The purpose of this study was to evaluate the association between patient and injury characteristics and treatment location using a national database. Study Design We performed an analysis of all burn patients admitted to United States hospitals participating in the Healthcare Cost and Utilization Project over 2 years. Univariate and multivariate analyses were performed to identify patient and injury factors associated with the likelihood of treatment at designated burn care facilities. Definitve care facilities were categorized as American Burn Association verified centers, non-verified burn centers, or other facilities. Results Over the two years, 29,971 burn patients were treated in 1,376 hospitals located in 19 participating states. A total of 6,712 (22%) patients were treated at verified centers, with 26% and 52% treated at non-verified or other facilities, respectively. Patients treated at verified centers were younger than those at non-verified or other facilities (33.1 years vs. 33.7 years vs. 41.9 years, p<0.001) and had a higher rate of inhalation injury (3.4% vs. 3.2% vs. 2.2%, p<0.001). Independent factors associated with treatment at verified centers include burns to the head/neck (RR 2.4, CI 2.1-2.7), hand (RR 1.8, CI 1.6-1.9), electrical injury (RR 1.4, CI 1.4, CI 1.2-1.7), and fewer co-morbidities (RR 0.55, CI 0.5-0.6). Conclusions More than two-thirds of significantly burned patients are treated at non-verified burn centers in the U.S. Many patients meeting ABA criteria for transfer to a burn center are being treated at non-burn center facilities. PMID:20193892

Variations in soil detachment rates after wildfire as a function of soil depth, flow properties, and root properties

USGS Publications Warehouse

Moody, John A.; Nyman, Peter

2013-01-01

Wildfire affects hillslope erosion through increased surface runoff and increased sediment availability, both of which contribute to large post-fire erosion events. Relations between soil detachment rate, soil depth, flow and root properties, and fire impacts are poorly understood and not represented explicitly in commonly used post-fire erosion models. Detachment rates were measured on intact soil cores using a modified tilting flume. The cores were mounted flush with the flume-bed and a measurement was made on the surface of the core. The core was extruded upward, cut off, and another measurement was repeated at a different depth below the original surface of the core. Intact cores were collected from one site burned by the 2010 Fourmile Canyon (FMC) fire in Colorado and from one site burned by the 2010 Pozo fire in California. Each site contained contrasting vegetation and soil types. Additional soil samples were collected alongside the intact cores and were analyzed in the laboratory for soil properties (organic matter, bulk density, particle-size distribution) and for root properties (root density and root-length density). Particle-size distribution and root properties were different between sites, but sites were similar in terms of bulk density and organic matter. Soil detachment rates had similar relations with non-uniform shear stress and non-uniform unit stream power. Detachment rates within single sampling units displayed a relatively weak and inconsistent relation to flow variables. When averaged across all clusters, the detachment rate displayed a linear relation to shear stress, but variability in soil properties meant that the shear stress accounted for only a small proportion of the overall variability in detachment rates (R2 = 0.23; R2 is the coefficient of determination). Detachment rate was related to root-length density in some clusters (R2 values up to 0.91) and unrelated in others (R2 values 2 value improved and the range of exponents became narrower by applying a multivariate regression model where boundary shear stress and root-length density were included as explanatory variables. This suggests that an erodibility parameter which incorporates the effects of both flow and root properties on detachment could improve the representation of sediment availability after wildfire.

Validation of the burns itch questionnaire.

PubMed

Van Loey, N E; Hofland, H W; Hendrickx, H; Van de Steenoven, J; Boekelaar, A; Nieuwenhuis, M K

2016-05-01

Itch (pruritus) is a common multidimensional complaint after burn that can persist for months to years. A questionnaire able to investigate itch and its consequences is imperative for clinical and research purposes. The current study investigated the factor structure, internal consistency and construct validity of the Burns Itch Questionnaire (BIQ), a questionnaire particularly focusing on itch in the burns population. The BIQ was completed by 195 respondents at 3 months after burn. An exploratory factor analysis (EFA) was performed to investigate the factor structure. EFA showed the BIQ comprised three latent factors: itch severity, sleep interference and daily life interference. This was re-evaluated in a confirmatory factor analysis that yielded good fit indices after removing two items. The three subscales showed to have high internal consistency (.89) and were able to distinguish between patients with severe and less severe complaints. In conclusion, the BIQ showed to be useful in persons suffering from itch following burns. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Results of Propellant Mixing Variable Study Using Precise Pressure-Based Burn Rate Calculations

NASA Technical Reports Server (NTRS)

Stefanski, Philip L.

2014-01-01

A designed experiment was conducted in which three mix processing variables (pre-curative addition mix temperature, pre-curative addition mixing time, and mixer speed) were varied to estimate their effects on within-mix propellant burn rate variability. The chosen discriminator for the experiment was the 2-inch diameter by 4-inch long (2x4) Center-Perforated (CP) ballistic evaluation motor. Motor nozzle throat diameters were sized to produce a common targeted chamber pressure. Initial data analysis did not show a statistically significant effect. Because propellant burn rate must be directly related to chamber pressure, a method was developed that showed statistically significant effects on chamber pressure (either maximum or average) by adjustments to the process settings. Burn rates were calculated from chamber pressures and these were then normalized to a common pressure for comparative purposes. The pressure-based method of burn rate determination showed significant reduction in error when compared to results obtained from the Brooks' modification of the propellant web-bisector burn rate determination method. Analysis of effects using burn rates calculated by the pressure-based method showed a significant correlation of within-mix burn rate dispersion to mixing duration and the quadratic of mixing duration. The findings were confirmed in a series of mixes that examined the effects of mixing time on burn rate variation, which yielded the same results.

The isotopic composition of methane in polar ice cores

NASA Technical Reports Server (NTRS)

Craig, H.; Chou, C. C.; Welhan, J. A.; Stevens, C. M.; Engelkemeir, A.

1988-01-01

Air bubbles in polar ice cores indicate that about 300 years ago the atmospheric mixing ratio of methane began to increase rapidly. Today the mixing ratio is about 1.7 parts per million by volume, and, having doubled once in the past several hundred years, it will double again in the next 60 years if current rates continue. Carbon isotope ratios in methane up to 350 years in age have been measured with as little as 25 kilograms of polar ice recovered in 4-meter-long ice-core segments. The data show that: (1) in situ microbiology or chemistry has not altered the ice-core methane concentrations, and (2) that the carbon-13 to carbon-12 ratio of atmospheric CH4 in ice from 100 years and 300 years ago was about 2 per mil lower than at present. Atmospheric methane has a rich spectrum of isotopic sources: the ice-core data indicate that anthropogenic burning of the earth's biomass is the principal cause of the recent C-13H4 enrichment, although other factors may also contribute.

Burn Pit Emissions Exposure and Respiratory and Cardiovascular Conditions Among Airborne Hazards and Open Burn Pit Registry Participants.

PubMed

Liu, Jason; Lezama, Nicholas; Gasper, Joseph; Kawata, Jennifer; Morley, Sybil; Helmer, Drew; Ciminera, Paul

2016-07-01

The aim of this study was to determine how burn pit emissions exposure is associated with the incidence of respiratory and cardiovascular conditions. We examined the associations between assumed geographic and self-reported burn pit emissions exposure and respiratory and cardiovascular outcomes in participants of the Airborne Hazards and Open Burn Pit Registry. We found significant dose-response associations for higher risk of self-reported emphysema, chronic bronchitis, or chronic obstructive pulmonary disease with increased days of deployment within 2 miles of selected burn pits (P-trend = 0.01) and self-reported burn pit smoke exposure (P-trend = 0.0005). We found associations between burn pit emissions exposure and higher incidence of post-deployment self-reported respiratory and cardiovascular conditions, but these findings should be interpreted with caution because the surrogate measurements of burn pit emissions exposure in this analysis may not reflect individual exposure levels.

Work-Related Burn Injuries Hospitalized in US Burn Centers: 2002 to 2011.

PubMed

Huang, Zhenna; Friedman, Lee S

2017-03-01

To develop a comprehensive definition to identify work-related burns in the National Burn Repository (NBR) based on multiple fields and describes injuries by occupation. The NBR, which is an inpatient dataset, was used to compare type and severity of burn injuries by occupation. Using the definition developed for this analysis, 22,969 burn injuries were identified as work-related. In contrast, the single work-related field intended to capture occupational injuries only captured 4696 cases. The highest numbers of burns were observed in construction/extraction, food preparation, and durable goods production occupations. Occupations with a mean total body surface area (TBSA) burned greater than 10% include transportation and material-moving, architecture and engineering, and arts/design/entertainment/sports/media occupations. The NBR dataset should be further utilized for occupational burn injury investigations and multiple fields should be considered for case ascertainment.

Uncertainty analysis of moderate- versus coarse-scale satellite fire products for quantifying agricultural burning: Implications for Air Quality in European Russia, Belarus, and Lithuania

NASA Astrophysics Data System (ADS)

McCarty, J. L.; Krylov, A.; Prishchepov, A. V.; Banach, D. M.; Potapov, P.; Tyukavina, A.; Rukhovitch, D.; Koroleva, P.; Turubanova, S.; Romanenkov, V.

2015-12-01

Cropland and pasture burning are common agricultural management practices that negatively impact air quality at a local and regional scale, including contributing to short-lived climate pollutants (SLCPs). This research focuses on both cropland and pasture burning in European Russia, Lithuania, and Belarus. Burned area and fire detections were derived from 500 m and 1 km Moderate Resolution Imaging Spectroradiometer (MODIS), 30 m Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 Operational Land Imager (OLI) data. Carbon, particulate matter, volatile organic carbon (VOCs), and harmful air pollutants (HAPs) emissions were then calculated using MODIS and Landsat-based estimates of fire and land-cover and land-use. Agricultural burning in Belarus, Lithuania, and European Russia showed a strong and consistent seasonal geographic pattern from 2002 to 2012, with the majority of fire detections occurring in March - June and smaller peak in July and August. Over this 11-year period, there was a decrease in both cropland and pasture burning throughout this region. For Smolensk Oblast, a Russian administrative region with comparable agro-environmental conditions to Belarus and Lithuania, a detailed analysis of Landsat-based burned area estimations for croplands and pastures and field data collected in summer 2014 showed that the agricultural burning area can be up to 10 times higher than the 1 km MODIS active fire estimates. In general, European Russia is the main source of agricultural burning emissions compared to Lithuania and Belarus. On average, all cropland burning in European Russia as detected by the MCD45A1 MODIS Burned Area Product emitted 17.66 Gg of PM10 while annual burning of pasture in Smolensk Oblast, Russia as detected by Landsat burn scars emitted 494.85 Gg of PM10, a 96% difference. This highlights that quantifying the contribution of pasture burning and burned area versus cropland burning in agricultural regions is important for accurately calculating carbonaceous emissions and emissions that negatively impact air quality.

Ejection of the Massive Hydrogen-rich Envelope Timed with the Collapse of the Stripped SN 2014C

PubMed Central

Margutti, Raffaella; Kamble, A.; Milisavljevic, D.; Zapartas, E.; de Mink, S. E.; Drout, M.; Chornock, R.; Risaliti, G.; Zauderer, B. A.; Bietenholz, M.; Cantiello, M.; Chakraborti, S.; Chomiuk, L.; Fong, W.; Grefenstette, B.; Guidorzi, C.; Kirshner, R.; Parrent, J. T.; Patnaude, D.; Soderberg, A. M.; Gehrels, N. C.; Harrison, F.

2017-01-01

We present multi-wavelength observations of SN 2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays ~40 keV. SN 2014C shows ordinary explosion parameters (Ek ~ 1.8 × 1051 erg and Mej ~ 1.7 M⊙). However, over an ~1 year timescale, SN 2014C evolved from an ordinary hydrogen-poor supernova into a strongly interacting, hydrogen-rich supernova, violating the traditional classification scheme of type-I versus type-II SNe. Signatures of the SN shock interaction with a dense medium are observed across the spectrum, from radio to hard X-rays, and revealed the presence of a massive shell of ~1 M⊙of hydrogen-rich material at ~6 × 1016 cm. The shell was ejected by the progenitor star in the decades to centuries before collapse. This result challenges current theories of massive star evolution, as it requires a physical mechanism responsible for the ejection of the deepest hydrogen layer of H-poor SN progenitors synchronized with the onset of stellar collapse. Theoretical investigations point at binary interactions and/or instabilities during the last nuclear burning stages as potential triggers of the highly time-dependent mass loss. We constrain these scenarios utilizing the sample of 183 SNe Ib/c with public radio observations. Our analysis identifies SN 2014C-like signatures in ~10% of SNe. This fraction is reasonably consistent with the expectation from the theory of recent envelope ejection due to binary evolution if the ejected material can survive in the close environment for 103–104 years. Alternatively, nuclear burning instabilities extending to core C-burning might play a critical role. PMID:28684881

Epidemiology and outcome analysis of 6325 burn patients: a five-year retrospective study in a major burn center in Southwest China

PubMed Central

Li, Haisheng; Yao, Zhihui; Tan, Jianglin; Zhou, Junyi; Li, Yi; Wu, Jun; Luo, Gaoxing

2017-01-01

Burns are a major cause of injury worldwide. We investigated the epidemiology and outcomes of burn patients in a major burn center in southwest China between 2011 and 2015 to provide guidance for burn prevention. Of the 6,325 included burn patients, 66.8% were male and 34.7% were 0 ~ 6 years old. The incidence of burns peaked in autumn. Scald was the most common cause of burns, which was predominant in patients aged 0 ~ 6 years. The mean total body surface area (TBSA) of burns was 13.4%, and patients with burns ≤10% TBSA comprised 64.1% of all cases. Patients with full-thickness burns accounted for 40.1% of all patients and 81.0% of operated patients; these burns were primarily caused by flame (34.8%), scald (21.0%), and electricity (20.4%). Fifty-six deaths occurred (mortality 0.9%), and risk factors included full-thickness burns, larger TBSA and older age. The median length of stay was 17 days, and major risk factors included more operations, better outcomes and larger TBSA. Our data showed that closer attention should be paid to children under 6 years old, males, incidents in autumn and scald burns to prevent burn injuries. Furthermore, individualized burn prevention and treatment measures based on related risk factors should be adopted. PMID:28383066

Burns in the Lebanon War 1982: "the blow and the cure".

PubMed

Eldad, A; Torem, M

1990-03-01

There were 70% more burns in the October 1973 war than in the Six Day War of 1967. This increase caused great concern and emphasized the need for better personal and crew protection against burns. Some of these measures were already implemented by the outbreak of the 1982 war in Lebanon. Analysis of the burn injuries of this war is the subject of this short report.

How robust are burn severity indices when applied in a new region? Evaluation of alternate field-based and remote-sensing methods

Treesearch

C. Alina Cansler; Donald McKenzie

2012-01-01

Remotely sensed indices of burn severity are now commonly used by researchers and land managers to assess fire effects, but their relationship to field-based assessments of burn severity has been evaluated only in a few ecosystems. This analysis illustrates two cases in which methodological refinements to field-based and remotely sensed indices of burn severity...

Analyses of biomass burning contribution to aerosol in Zhengzhou during wheat harvest season in 2015

NASA Astrophysics Data System (ADS)

Chen, Hongyang; Yin, Shasha; Li, Xiao; Wang, Jia; Zhang, Ruiqin

2018-07-01

Ambient PM2.5 samples were collected in suburban area of Zhengzhou, China to investigate the impact of straw open burning on local aerosol during wheat harvest season in 2015. Secondary formation and accumulation processes were found under unfavorable meteorological conditions through the chemical composition analysis in PM2.5. And spatial and temporal variation of the agricultural activities were observed through MODIS fire spots data combined with back trajectory analysis. Results showed elevated levoglucosan was affected directly during biomass burning episodes and transportation periods. In order to estimate the contribution, levoglucosan/K+ combined with levoglucosan/mannosan were analyzed to identify biomass burning sources. And the results showed that levoglucosan were emitted from straw burning mixing with softwood combustion during the study period, emphasizing that wood combustion for households was non-negligible which consists part of the levoglucosan background in Zhengzhou aerosol. Based on emission factors (levoglucosan/OC or levoglucosan/PM2.5) summarized by laboratory simulation experiments, the study period was divided into 7 depending on the former characteristics to estimate the contribution of biomass burning to aerosol, and the average contributions of biomass burning emission to OC and PM2.5 were 46% and 13% relatively, indicating biomass burning have a significant impact on ambient aerosol levels during harvest season.

Possibility study of gasifier with axial circulating flue gas for reducing Tar

NASA Astrophysics Data System (ADS)

Poowadin, T.; Polsongkram, M.; Khantikomol, P.

2018-01-01

This present research article aims to study the possibility of gasification by axial core flue gas circulating kiln and find the efficiency of syngas production. An axial core flue gas circulating tube was installed in the center of the updraft gasifier in purposing of tar reducing. In the present study, the eucalyptus wood chip 4, 8, and 10 kg with the moisture content 16% were examined. Several type-K thermocouples were employed to measure the temperatures at preheat, combustion, reduction, pyrolysis, drying, and gas outlet zone. The results showed that the temperatures in the combustion and the reduction zone of the kiln with the axial core flue gas recirculating were lower than the kiln without the core owing to installing the core would reduce the combustion zone area in biomass burning. Obviously, the temperature in the pyrolysis and drying zone were nearly the same as both with and without the core. In consideration of syngas components, it was found that CO production from the gasifier with the core was higher than the gasifier without the core about 25%. Other gases, however, were almost same. The syngas production efficiency obtained from the gasifier with the core decreased with increasing the mass of biomass. It showed that the highest efficiency was 30% at 4 kg supplying biomass. In comparison, the efficiencies of both the kilns with and without the core were not different. For liquid product, the amount of liquid decreased about 47.23% comparing with the gasifier without the core.

Determination of burning area and port volume in complex burning regions of a solid rocket motor

NASA Technical Reports Server (NTRS)

Kingsbury, J. A.

1977-01-01

An analysis of the geometry of the burning in both star-cylindrical port interface regions and regions of partially inhibited slots is presented. Some characteristics parameters are defined and illustrated. Methods are proposed for calculating burning areas which functionally depend only on the total distance burned. According to this method, several points are defined where abrupt changes in geometry occur, and these are tracked throughout the burn. Equations are developed for computing port perimeter and port area at pre-established longitudinal positions. Some common formulas and some newly developed formulas are then used to compute burning surface area and port volume. Some specific results are presented for the solid rocket motor committed to the space shuttle project.

Double-detonation Sub-Chandrasekhar Supernovae: Synthetic Observables for Minimum Helium Shell Mass Models

NASA Astrophysics Data System (ADS)

Kromer, M.; Sim, S. A.; Fink, M.; Röpke, F. K.; Seitenzahl, I. R.; Hillebrandt, W.

2010-08-01

In the double-detonation scenario for Type Ia supernovae, it is suggested that a detonation initiates in a shell of helium-rich material accreted from a companion star by a sub-Chandrasekhar-mass white dwarf. This shell detonation drives a shock front into the carbon-oxygen white dwarf that triggers a secondary detonation in the core. The core detonation results in a complete disruption of the white dwarf. Earlier studies concluded that this scenario has difficulties in accounting for the observed properties of Type Ia supernovae since the explosion ejecta are surrounded by the products of explosive helium burning in the shell. Recently, however, it was proposed that detonations might be possible for much less massive helium shells than previously assumed (Bildsten et al.). Moreover, it was shown that even detonations of these minimum helium shell masses robustly trigger detonations of the carbon-oxygen core (Fink et al.). Therefore, it is possible that the impact of the helium layer on observables is less than previously thought. Here, we present time-dependent multi-wavelength radiative transfer calculations for models with minimum helium shell mass and derive synthetic observables for both the optical and γ-ray spectral regions. These differ strongly from those found in earlier simulations of sub-Chandrasekhar-mass explosions in which more massive helium shells were considered. Our models predict light curves that cover both the range of brightnesses and the rise and decline times of observed Type Ia supernovae. However, their colors and spectra do not match the observations. In particular, their B - V colors are generally too red. We show that this discrepancy is mainly due to the composition of the burning products of the helium shell of the Fink et al. models which contain significant amounts of titanium and chromium. Using a toy model, we also show that the burning products of the helium shell depend crucially on its initial composition. This leads us to conclude that good agreement between sub-Chandrasekhar-mass explosions and observed Type Ia supernovae may still be feasible but further study of the shell properties is required.

In vivo burn diagnosis by camera-phone diffuse reflectance laser speckle detection.

PubMed

Ragol, S; Remer, I; Shoham, Y; Hazan, S; Willenz, U; Sinelnikov, I; Dronov, V; Rosenberg, L; Bilenca, A

2016-01-01

Burn diagnosis using laser speckle light typically employs widefield illumination of the burn region to produce two-dimensional speckle patterns from light backscattered from the entire irradiated tissue volume. Analysis of speckle contrast in these time-integrated patterns can then provide information on burn severity. Here, by contrast, we use point illumination to generate diffuse reflectance laser speckle patterns of the burn. By examining spatiotemporal fluctuations in these time-integrated patterns along the radial direction from the incident point beam, we show the ability to distinguish partial-thickness burns in a porcine model in vivo within the first 24 hours post-burn. Furthermore, our findings suggest that time-integrated diffuse reflectance laser speckle can be useful for monitoring burn healing over time post-burn. Unlike conventional diffuse reflectance laser speckle detection systems that utilize scientific or industrial-grade cameras, our system is designed with a camera-phone, demonstrating the potential for burn diagnosis with a simple imager.

In vivo burn diagnosis by camera-phone diffuse reflectance laser speckle detection

PubMed Central

Ragol, S.; Remer, I.; Shoham, Y.; Hazan, S.; Willenz, U.; Sinelnikov, I.; Dronov, V.; Rosenberg, L.; Bilenca, A.

2015-01-01

Burn diagnosis using laser speckle light typically employs widefield illumination of the burn region to produce two-dimensional speckle patterns from light backscattered from the entire irradiated tissue volume. Analysis of speckle contrast in these time-integrated patterns can then provide information on burn severity. Here, by contrast, we use point illumination to generate diffuse reflectance laser speckle patterns of the burn. By examining spatiotemporal fluctuations in these time-integrated patterns along the radial direction from the incident point beam, we show the ability to distinguish partial-thickness burns in a porcine model in vivo within the first 24 hours post-burn. Furthermore, our findings suggest that time-integrated diffuse reflectance laser speckle can be useful for monitoring burn healing over time post-burn. Unlike conventional diffuse reflectance laser speckle detection systems that utilize scientific or industrial-grade cameras, our system is designed with a camera-phone, demonstrating the potential for burn diagnosis with a simple imager. PMID:26819831

A Pebble-Bed Breed-and-Burn Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenspan, Ehud

2016-03-31

The primary objective of this project is to use three-dimensional fuel shuffling in order to reduce the minimum peak radiation damage of ~550 dpa present Breed-and-Burn (B&B) fast nuclear reactor cores designs (they feature 2-D fuel shuffling) call for to as close as possible to the presently accepted value of 200 dpa thereby enabling earlier commercialization of B&B reactors which could make substantial contribution to energy sustainability and economic stability without need for fuel recycling. Another objective is increasing the average discharge burnup for the same peak discharge burnup thereby (1) increasing the fuel utilization of 2-D shuffled B&B reactorsmore » and (2) reducing the reprocessing capacity required to support a given capacity of FRs that are to recycle fuel.« less

Conceptual design study of small long-life PWR based on thorium cycle fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subkhi, M. Nurul; Su'ud, Zaki; Waris, Abdul

2014-09-30

A neutronic performance of small long-life Pressurized Water Reactor (PWR) using thorium cycle based fuel has been investigated. Thorium cycle which has higher conversion ratio in thermal region compared to uranium cycle produce some significant of {sup 233}U during burn up time. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.3, while the multi-energy-group diffusion calculations were optimized in whole core cylindrical two-dimension R-Z geometry by SRAC-CITATION. this study would be introduced thorium nitride fuel system which ZIRLO is the cladding material. The optimization of 350 MWt small long life PWRmore » result small excess reactivity and reduced power peaking during its operation.« less

r-process nucleosynthesis in dynamic helium-burning environments

NASA Technical Reports Server (NTRS)

Cowan, J. J.; Cameron, A. G. W.; Truran, J. W.

1985-01-01

The results of an extended examination of r-process nucleosynthesis in helium-burning enviroments are presented. Using newly calculated nuclear rates, dynamical r-process calculations have been made of thermal runaways in helium cores typical of low-mass stars and in the helium zones of stars undergoing supernova explosions. These calculations show that, for a sufficient flux of neutrons produced by the C-13 neutron source, r-process nuclei in solar proportions can be produced. The conditions required for r-process production are found to be 10 to the 20th-10 to the 21st neutrons per cubic centimeter for times of 0.01-0.1 s and neutron number densities in excess of 10 to the 19th per cubic centimeter for times of about 1 s. The amount of C-13 required is found to be exceedingly high - larger than is found to occur in any current stellar evolutionary model. It is thus unlikely that these helium-burning environments are responsible for producing the bulk of the r-process elements seen in the solar system.

Combustion-transition interaction in a jet flame

NASA Astrophysics Data System (ADS)

Yule, A. J.; Chigier, N. A.; Ralph, S.; Boulderstone, R.; Ventura, J.

1980-01-01

The transition between laminar and turbulent flow in a round jet flame is studied experimentally. Comparison is made between transition in non-burning and burning jets and between jet flames with systematic variation in initial Reynolds number and equivalence ratio. Measurements are made using laser anemometry, miniature thermocouples, ionization probes, laser-schlieren and high speed cine films. Compared with the cold jet, the jet flame has a longer potential core, undergoes a slower transition to turbulence, has lower values of fluctuating velocity near the burner but higher values further downstream, contains higher velocity gradients in the mixing layer region although the total jet width does not alter greatly in the first twenty diameters. As in the cold jet, transitional flow in the flame contains waves and vortices and these convolute and stretch the initially laminar interface burning region. Unlike the cold jet, which has Kelvin-Helmholtz instabilities, the jet flame can contain at least two initial instabilities; an inner high frequency combustion driven instability and an outer low frequency instability which may be influenced by buoyancy forces.

Analysis of Advanced Fuel Assemblies and Core Designs for the Current and Next Generations of LWRs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ragusa, Jean; Vierow, Karen

2011-09-01

The objective of the project is to design and analyze advanced fuel assemblies for use in current and future light water reactors and to assess their ability to reduce the inventory of transuranic elements, while preserving operational safety. The reprocessing of spent nuclear fuel can delay or avoid the need for a second geological repository in the US. Current light water reactor fuel assembly designs under investigation could reduce the plutonium inventory of reprocessed fuel. Nevertheless, these designs are not effective in stabilizing or reducing the inventory of minor actinides. In the course of this project, we developed and analyzedmore » advanced fuel assembly designs with improved thermal transmutation capability regarding transuranic elements and especially minor actinides. These designs will be intended for use in thermal spectrum (e.g., current and future fleet of light water reactors in the US). We investigated various fuel types, namely high burn-up advanced mixed oxides and inert matrix fuels, in various geometrical designs that are compliant with the core internals of current and future light water reactors. Neutronic/thermal hydraulic effects were included. Transmutation efficiency and safety parameters were used to rank and down-select the various designs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Stephanie B.; Harding, Eric C.; Knapp, Patrick F.

The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. In this work, we show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated bymore » the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Lastly, analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 10 24 e/cm 3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.« less

Non-radial oscillation modes with long lifetimes in giant stars.

PubMed

De Ridder, Joris; Barban, Caroline; Baudin, Frédéric; Carrier, Fabien; Hatzes, Artie P; Hekker, Saskia; Kallinger, Thomas; Weiss, Werner W; Baglin, Annie; Auvergne, Michel; Samadi, Réza; Barge, Pierre; Deleuil, Magali

2009-05-21

Towards the end of their lives, stars like the Sun greatly expand to become red giant stars. Such evolved stars could provide stringent tests of stellar theory, as many uncertainties of the internal stellar structure accumulate with age. Important examples are convective overshooting and rotational mixing during the central hydrogen-burning phase, which determine the mass of the helium core, but which are not well understood. In principle, analysis of radial and non-radial stellar oscillations can be used to constrain the mass of the helium core. Although all giants are expected to oscillate, it has hitherto been unclear whether non-radial modes are observable at all in red giants, or whether the oscillation modes have a short or a long mode lifetime, which determines the observational precision of the frequencies. Here we report the presence of radial and non-radial oscillations in more than 300 giant stars. For at least some of the giants, the mode lifetimes are of the order of a month. We observe giant stars with equally spaced frequency peaks in the Fourier spectrum of the time series, as well as giants for which the spectrum seems to be more complex. No satisfactory theoretical explanation currently exists for our observations.

Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

NASA Astrophysics Data System (ADS)

Hansen, S. B.; Harding, E. C.; Knapp, P. F.; Gomez, M. R.; Nagayama, T.; Bailey, J. E.

2018-05-01

The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. We show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated by the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 1024 e/cm3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.

Evolutionary sequences of very hot, low-mass, accreting white dwarfs with application to symbiotic variables and ultrasoft/supersoft low-luminosity x-ray sources

NASA Technical Reports Server (NTRS)

Sion, Edward M.; Starrfield, Sumner G.

1994-01-01

We present the first detailed model results of quasi-static evolutionary sequences of very hot low-mass white dwarfs accreting hydrogen-rich material at rates between 1 x 10(exp -7) and 1 x 10(exp -9) solar mass/yr. Most of the sequences were generated from starting models whose core thermal structures were not thermally relaxed in the thermal pulse cycle-averaged sense of an asymptotic giant branch stellar core. Hence, the evolution at constant accretion rate was not invariably characterized by series of identical shell flashes. Sequences exhibiting stable steady state nuclear burning at the accretion supply rate as well as sequences exhibiting recurrent thermonuclear shell flashes are presented and discussed. In some cases, the white dwarf accretors remain small (less than 10(exp 11) cm) and very hot even during the shell flash episode. They then experience continued but reduced hydrogen shell burning during the longer quiescent intervals while their surface temperatures increase both because of compressional heating and envelope structure readjustment in response to accretion over thousands of years. Both accretion and continued hydrogen burning power these models with luminosities of a few times 10(exp 37) ergs/s. We suggest that the physical properties of these model sequences are of considerable relevance to the observed outburst and quiescent behavior of those symbiotic variables and symbiotic novae containing low-mass white dwarfs. We also suggest that our models are relevant to the observational characteristics of the growing class of low-luminosity, supersoft/ultrasoft X-ray sources in globular clusters, and the Magellanic Clouds.

Beneficial Effects of Hydrogen-Rich Saline on Early Burn-Wound Progression in Rats

PubMed Central

Guo, Song Xue; Jin, Yun Yun; Fang, Quan; You, Chuan Gang; Wang, Xin Gang; Hu, Xin Lei; Han, Chun-Mao

2015-01-01

Introduction Deep burn wounds undergo a dynamic process known as wound progression that results in a deepening and extension of the initial burn area. The zone of stasis is more likely to develop more severe during wound progression in the presence of hypoperfusion. Hydrogen has been reported to alleviate injury triggered by ischaemia/reperfusion and burns in various organs by selectively quenching oxygen free radicals. The aim of this study was to investigate the possible protective effects of hydrogen against early burn-wound progression. Methods Deep-burn models were established through contact with a boiled, rectangular, brass comb for 20 s. Fifty-six Sprague-Dawley rats were randomly divided into sham, burn plus saline, and burn plus hydrogen-rich saline (HS) groups with sacrifice and analysis at various time windows (6 h, 24 h, 48 h) post burn. Indexes of oxidative stress, apoptosis and autophagy were measured in each group. The zone of stasis was evaluated using immunofluorescence staining, ELISA, and Western blot to explore the underlying effects and mechanisms post burn. Results The burn-induced increase in malondialdehyde was markedly reduced with HS, while the activities of endogenous antioxidant enzymes were significantly increased. Moreover, HS treatment attenuated increases in apoptosis and autophagy postburn in wounds, according to the TUNEL staining results and the expression analysis of Bax, Bcl-2, caspase-3, Beclin-1 and Atg-5 proteins. Additionally, HS lowered the level of myeloperoxidase and expression of TNF-α, IL-1β, and IL-6 in the zone of stasis while augmenting IL-10. The elevated levels of Akt phosphorylation and NF-κB p65 expression post burn were also downregulated by HS management. Conclusion Hydrogen can attenuate early wound progression following deep burn injury. The beneficial effect of hydrogen was mediated by attenuating oxidative stress, which inhibited apoptosis and inflammation, and the Akt/NF-κB signalling pathway may be involved in regulating the release of inflammatory cytokines. PMID:25874619

Contributions of Kansas rangeland burning to ambient O3: Analysis of data from 2001 to 2016.

PubMed

Liu, Zifei; Liu, Yang; Murphy, James P; Maghirang, Ronaldo

2018-03-15

Prescribed range/pasture burning is a common practice in Kansas to enhance the nutritional value of native grasses and control invading weeds, trees, and brush. A major concern associated with the burning is the contribution of smoke to elevated ground level ambient ozone (O 3 ). The objective of this study is to estimate contributions of Kansas rangeland burning to ambient O 3 mixing ratios through regression analysis (1) between observed O 3 data and available satellite burn activity data from 2001 to 2016; and (2) between observed O 3 data and the smoke contributions to PM 2.5 which were resolved from receptor modeling. Positive correlations were observed between ambient O 3 levels and the acres burned each year estimated from satellite imagery. When burned acres in April were larger than or equal to 1.9 million, O 3 >70ppb occurred at least at one of the ten monitoring sites in Kansas. Statistical regression models of daily maximum 8-hour O 3 mixing ratios were developed at each of the ten monitoring sites using meteorological predictors. The O 3 model residuals that were not explained by the meteorological effect models were affected by PM 2.5 contributors including sulfate/industrial sources and emissions that generated secondary organic particles, such as rangeland burning, which were derived from receptor modeling. The average O 3 model residual on the high O 3 days in April was 21±9ppb, which was likely associated with smoke emissions from burning. Research will continue to obtain daily satellite burn activity data and to correlate burn data with daily O 3 data, so that modeling of O 3 levels can be improved under influences of daily burn activities. Less frequency of high O 3 days was observed in April since 2011, which may be partly due to implementation of the Flint Hills Smoke Management Plan which promoted better timing of burns. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of pre-existing malnutrition on pediatric burn mortality in a sub-Saharan African burn unit.

PubMed

Grudziak, Joanna; Snock, Carolyn; Mjuweni, Stephen; Gallaher, Jared; Cairns, Bruce; Charles, Anthony

2017-11-01

Nutritional status predicts burn outcomes in the developed world, but its effect on burn mortality in the developing world has not been widely studied. In sub Saharan Africa, burn is primarily a disease of children, and the majority of children in sub-Saharan Africa are malnourished. We therefore sought to determine the prevalence and effect of malnutrition on burn mortality at our institution. This is a retrospective review of children aged 0-5, with anthropomorphic measurements available, who were admitted to our burn unit from July 2011 to May 2016. Age-adjusted Z scores were calculated for height, weight, weight for height, and mid-upper arm circumference (MUAC). Following bivariate analysis, we used logistic regression to construct a fully adjusted model of predictors of mortality. Of the 1357 admitted patients, 839 (61.2%) were aged 0-5. Of those, 512 (62.9%) had one or more anthropomorphic measurements available, and were included in the analysis. 54% were male, and the median age was 28 months. The median TBSA was 15%, with a majority of burns caused by scalds (77%). Mortality was 16%. Average Z-score for any of the indicators of malnutrition was -1.45±1.66. TBSA (OR: 1.08, 95% CI: 1.06, 1.11), decreasing Z-score (OR: 1.19, 95% CI: 1.00, 1.41), and flame burn (OR: 2.51, 95% CI: 1.40, 4.49) were associated with an increase in mortality. Preexisting malnutrition in burn patients in sub-Saharan Africa increases odds of mortality after controlling for significant covariates. Survival of burn patients in this region will not reach that of the developed world until a strategy of aggressive nutritional support is implemented in this population. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Development of the life impact burn recovery evaluation (LIBRE) profile: assessing burn survivors' social participation.

PubMed

Kazis, Lewis E; Marino, Molly; Ni, Pengsheng; Soley Bori, Marina; Amaya, Flor; Dore, Emily; Ryan, Colleen M; Schneider, Jeff C; Shie, Vivian; Acton, Amy; Jette, Alan M

2017-10-01

Measuring the impact burn injuries have on social participation is integral to understanding and improving survivors' quality of life, yet there are no existing instruments that comprehensively measure the social participation of burn survivors. This project aimed to develop the Life Impact Burn Recovery Evaluation Profile (LIBRE), a patient-reported multidimensional assessment for understanding the social participation after burn injuries. 192 questions representing multiple social participation areas were administered to a convenience sample of 601 burn survivors. Exploratory factor analysis and confirmatory factor analysis (CFA) were used to identify the underlying structure of the data. Using item response theory methods, a Graded Response Model was applied for each identified sub-domain. The resultant multidimensional LIBRE Profile can be administered via Computerized Adaptive Testing (CAT) or fixed short forms. The study sample included 54.7% women with a mean age of 44.6 (SD 15.9) years. The average time since burn injury was 15.4 years (0-74 years) and the average total body surface area burned was 40% (1-97%). The CFA indicated acceptable fit statistics (CFI range 0.913-0.977, TLI range 0.904-0.974, RMSEA range 0.06-0.096). The six unidimensional scales were named: relationships with family and friends, social interactions, social activities, work and employment, romantic relationships, and sexual relationships. The marginal reliability of the full item bank and CATs ranged from 0.84 to 0.93, with ceiling effects less than 15% for all scales. The LIBRE Profile is a promising new measure of social participation following a burn injury that enables burn survivors and their care providers to measure social participation.

Florida panther habitat use response to prescribed fire

USGS Publications Warehouse

Dees, Catherine S.; Clark, Joseph D.; van Manen, Frank T.

2001-01-01

The Florida panther (Puma concolor coryi) is one of the most endangered mammals in the world, with only 30-50 adults surviving in and around Florida Panther National Wildlife Refuge and the adjacent Big Cypress National Preserve. Managers at these areas conduct annual prescribed burns in pine (Pinus sp.) as a cost-effective method of managing wildlife habitat. Our objectives were to determine if temporal and spatial relationships existed between prescribed fire an panther use of pine. to accomplish this, we paired fire-event data from the Refuge an the Preserve with panther radiolocations collected between 1989 and 1998, determined the time that had elapsed since burning had occurred in management units associated with the radiolocations, and generated a frequency distribution based on those times. We then generated ant expected frequency distribution, based on random use relative to time since burning. This analysis revealed that panther use of burned pine habitats was greatest during the first year after a management unit was burned. Also, compositional analysis indicated that panthers were more likely to position their home ranges in areas that contained pine. We conclude that prescribed burning is important to panther ecology. We suggest that panthers were attracted to <1-year-old burns because of white-tailed deer (Odocoileus virginianus) and other prey responses to vegetation and structural changed caused by the prescribed fires. The strong selection for stands burned within 1 year is a persuasive indication that it is the burning in pine, rather than the pine per se, that most influenced habitat use. Before burning rotation lengths are reduced, however, we suggest managers determine effects of shorter burning intervals on vegetation composition and evaluate the landscape-scale changes that would result. 

Benchmarks for multidimensional recovery after burn injury in young adults: the development, validation, and testing of the American Burn Association/Shriners Hospitals for Children young adult burn outcome questionnaire.

PubMed

Ryan, Colleen M; Schneider, Jeffrey C; Kazis, Lewis E; Lee, Austin; Li, Nien-Chen; Hinson, Michelle; Bauk, Helena; Peck, Michael; Meyer, Walter J; Palmieri, Tina; Pidcock, Frank S; Reilly, Debra; Tompkins, Ronald G

2013-01-01

Although data exist on burn survival, there are little data on long-term burn recovery. Patient-centered health outcomes are useful in monitoring and predicting recovery and evaluating treatments. An outcome questionnaire for young adult burn survivors was developed and tested. This 5-year (2003-2008) prospective, controlled, multicenter study included burned and nonburned adults ages 19 to 30 years. The Young Adult Burn Outcome Questionnaires were completed at initial contact, 10 days, and 6 and 12 months. Factor analysis established construct validity. Reliability assessments used Cronbach α and test-retest. Recovery patterns were investigated using generalized linear models, with generalized estimating equations using mixed models and random effects. Burned (n = 153) and nonburned subjects (n = 112) completed 620 questionnaires (47 items). Time from injury to first questionnaire administration was 157 ± 36 days (mean ± SEM). Factor analysis included 15 factors: Physical Function, Fine Motor Function, Pain, Itch, Social Function Limited by Physical Function, Perceived Appearance, Social Function Limited by Appearance, Sexual Function, Emotion, Family Function, Family Concern, Satisfaction With Symptom Relief, Satisfaction With Role, Work Reintegration, and Religion. Cronbach α ranged from 0.72 to 0.92, with 11 scales >0.8. Test-retest reliability ranged from 0.29 to 0.94, suggesting changes in underlying health status after burns. Recovery curves in five domains, Itch, Perceived Appearance, Social Function Limited by Appearance, Family Concern, and Satisfaction with Symptom Relief, remained below the reference group at 24 months. The Young Adult Burn Outcome Questionnaire is a reliable and valid instrument for multidimensional functional outcomes assessment. Recovery in some domains was incomplete.

Evidence of historical mining inferred from metal concentration of alluvial sediments in the Bernese Alps

NASA Astrophysics Data System (ADS)

Carvalho, Filipe; Schulte, Lothar

2017-04-01

Metal pollution is normally associated with modern day industrialization. However, evidences of anthropogenic metal pollution date back to the Palaeolithic, were the domestication of fire contributed to an increase of trace metals released from the burning wood. Large-scale metal pollution started during the Roman period with the increase of mining and smelting activities. The production of metals during this period was quite rudimentary and highly polluting, contributing to a raise of metal concentrations in the atmosphere and subsequently in sediments and soils. Towards the modern period, production methods were improved, especially since the industrial revolution, but continued to release pollutants to the environment. The aim of this study is to identify periods of increased mining activity though the analysis of sedimentary records. For this purpose, we study the geochemical response of trace metals in sedimentary cores from the Aare and Lütschine delta plains, located at the Bernese Alps. The focus of this analysis is the detection of metal concentration anomalies from the last 3000 years. The analysis is based on the X-Ray Fluorescence (AVATECH XRF core scanner) response of the chemical elements copper (Cu), zinc (Zn) and lead (Pb) contained in eight cores with depths down to 10 meter. All data was filtered in order to remove the noise from natural processes such as the increase of trace metal concentrations in organic rich horizons and to select the highest peaks of these metals. Results show similar trends in all the analysed cores and indicate three major pulses of trace metal concentration during the Roman Period, Early Medieval Age and a general increase of metal concentration during the Modern era, which can evidence mining and smelting activities. Periods of lower trace metal concentrations and shifts in concentration trends relate accurately with central Europe social and economic transitions, migratory events and significant demographic variations. It is also possible to identify some trace metal peaks during the late Neolithic period. The findings of archaeological sites from this region support the assumption of these possible early pollution periods.

Hybrid Reduced Order Modeling Algorithms for Reactor Physics Calculations

NASA Astrophysics Data System (ADS)

Bang, Youngsuk

Reduced order modeling (ROM) has been recognized as an indispensable approach when the engineering analysis requires many executions of high fidelity simulation codes. Examples of such engineering analyses in nuclear reactor core calculations, representing the focus of this dissertation, include the functionalization of the homogenized few-group cross-sections in terms of the various core conditions, e.g. burn-up, fuel enrichment, temperature, etc. This is done via assembly calculations which are executed many times to generate the required functionalization for use in the downstream core calculations. Other examples are sensitivity analysis used to determine important core attribute variations due to input parameter variations, and uncertainty quantification employed to estimate core attribute uncertainties originating from input parameter uncertainties. ROM constructs a surrogate model with quantifiable accuracy which can replace the original code for subsequent engineering analysis calculations. This is achieved by reducing the effective dimensionality of the input parameter, the state variable, or the output response spaces, by projection onto the so-called active subspaces. Confining the variations to the active subspace allows one to construct an ROM model of reduced complexity which can be solved more efficiently. This dissertation introduces a new algorithm to render reduction with the reduction errors bounded based on a user-defined error tolerance which represents the main challenge of existing ROM techniques. Bounding the error is the key to ensuring that the constructed ROM models are robust for all possible applications. Providing such error bounds represents one of the algorithmic contributions of this dissertation to the ROM state-of-the-art. Recognizing that ROM techniques have been developed to render reduction at different levels, e.g. the input parameter space, the state space, and the response space, this dissertation offers a set of novel hybrid ROM algorithms which can be readily integrated into existing methods and offer higher computational efficiency and defendable accuracy of the reduced models. For example, the snapshots ROM algorithm is hybridized with the range finding algorithm to render reduction in the state space, e.g. the flux in reactor calculations. In another implementation, the perturbation theory used to calculate first order derivatives of responses with respect to parameters is hybridized with a forward sensitivity analysis approach to render reduction in the parameter space. Reduction at the state and parameter spaces can be combined to render further reduction at the interface between different physics codes in a multi-physics model with the accuracy quantified in a similar manner to the single physics case. Although the proposed algorithms are generic in nature, we focus here on radiation transport models used in support of the design and analysis of nuclear reactor cores. In particular, we focus on replacing the traditional assembly calculations by ROM models to facilitate the generation of homogenized cross-sections for downstream core calculations. The implication is that assembly calculations could be done instantaneously therefore precluding the need for the expensive evaluation of the few-group cross-sections for all possible core conditions. Given the generic natures of the algorithms, we make an effort to introduce the material in a general form to allow non-nuclear engineers to benefit from this work.

Burn prevention in Zambia: a targeted epidemiological approach.

PubMed

Heard, Jason P; Latenser, Barbara A; Liao, Junlin

2013-01-01

The aim of this study is to assess primary burn prevention knowledge in a rural Zambian population that is disproportionately burdened by burn injuries. A 10-question survey was completed by youths, and a 15-question survey was completed by adults. The survey was available in both English and Nyanja. The surveys were designed to test their knowledge in common causes, first aid, and emergency measures regarding burn injuries. Logistic regression analysis was used to explore relationships between burn knowledge, age, school, and socioeconomic variables. A burn prevention coloring book, based on previous local epidemiological data, was also distributed to 800 school age youths. Five hundred fifty youths and 39 adults completed the survey. The most significant results show knowledge deficits in common causes of burns, first aid treatment of a burn injury, and what to do in the event of clothing catching fire. Younger children were more likely to do worse than older children. The adults performed better than the youths, but still lack fundamental burn prevention and treatment knowledge. Primary burn prevention data from the youths and adults surveyed demonstrate a clear need for burn prevention and treatment education in this population. In a country where effective and sustainable burn care is lacking, burn prevention may be a better investment to reduce burn injury than large investments in healthcare resources.

Avifaunal responses to fire in southwestern montane forests along a burn severity gradient

USGS Publications Warehouse

Kotliar, N.B.; Kennedy, P.L.; Ferree, K.

2007-01-01

The effects of burn severity on avian communities are poorly understood, yet this information is crucial to fire management programs. To quantify avian response patterns along a burn severity gradient, we sampled 49 random plots (2001-2002) at the 17 351-ha Cerro Grande Fire (2000) in New Mexico, USA. Additionally, pre-fire avian surveys (1986-1988, 1990) created a unique opportunity to quantify avifaunal changes in 13 pre-fire transects (resampled in 2002) and to compare two designs for analyzing the effects of unplanned disturbances: after-only analysis and before-after comparisons. Distance analysis was used to calculate densities. We analyzed after-only densities for 21 species using gradient analysis, which detected a broad range of responses to increasing burn severity: (I) large significant declines, (II) weak, but significant declines, (III) no significant density changes, (IV) peak densities in low- or moderate-severity patches, (V) weak, but significant increases, and (VI) large significant increases. Overall, 71% of the species included in the after-only gradient analysis exhibited either positive or neutral density responses to fire effects across all or portions of the severity gradient (responses III-VI). We used pre/post pairs analysis to quantify density changes for 15 species using before-after comparisons; spatiotemporal variation in densities was large and confounded fire effects for most species. Only four species demonstrated significant effects of burn severity, and their densities were all higher in burned compared to unburned forests. Pre- and post-fire community similarity was high except in high-severity areas. Species richness was similar pre- and post-fire across all burn severities. Thus, ecosystem restoration programs based on the assumption that recent severe fires in Southwestern ponderosa pine forests have overriding negative ecological effects are not supported by our study of post-fire avian communities. This study illustrates the importance of quantifying burn severity and controlling confounding sources of spatiotemporal variation in studies of fire effects. After-only gradient analysis can be an efficient tool for quantifying fire effects. This analysis can also augment historical data sets that have small samples sizes coupled with high non-process variation, which limits the power of before-after comparisons. ?? 2007 by the Ecological Society of America.

The use of an atmospheric dispersion model to determine influence regions in the Prince George, B.C. airshed from the burning of open wood waste piles.

PubMed

Ainslie, B; Jackson, P L

2009-06-01

A means of determining air emission source regions adversely influencing the city of Prince George, British Columbia, Canada from potential burning of isolated piles of mountain pine beetle-killed lodge pole pine is presented. The analysis uses the CALPUFF atmospheric dispersion model to identify safe burning regions based on atmospheric stability and wind direction. Model results show that the location and extent of influence regions is sensitive to wind speed, wind direction, atmospheric stability and a threshold used to quantify excessive concentrations. A concentration threshold based on the Canada Wide PM(2.5) Standard is used to delineate the influence regions while Environment Canada's (EC) daily ventilation index (VI) is used to quantify local atmospheric stability. Results from the analysis, to be used by air quality meteorologists in assessing daily requests for burning permits, are presented as a series of maps delineating acceptable burning locations for sources placed at various distances from the city center and under different ventilation conditions. The results show that no burning should be allowed within 10 km of the city center; under poor ventilation conditions, no burning should be allowed within 20 km of the city center; under good ventilation conditions, burning can be allowed within 10-15 km of the city center; under good to fair ventilation conditions, burning can be allowed beyond 15 km of the city center; and if the wind direction can be reliably forecast, burning can be allowed between 5 and 10 km downwind of the city center under good ventilation conditions.

Experiments and analysis concerning the use of external burning to reduce aerospace vehicle transonic drag. Ph.D. Thesis - Maryland Univ., 1991

NASA Technical Reports Server (NTRS)

Trefny, Charles J.

1992-01-01

The external combustion of hydrogen to reduce transonic drag was investigated. A control volume analysis is developed and indicates that the specific impulse performance of external burning is competitive with other forms of airbreathing propulsion and depends on the fuel-air ratio, freestream Mach number, and the severity of the base drag. A method is presented for sizing fuel injectors for a desired fuel-air ratio in the unconfined stream. A two-dimensional Euler analysis is also presented which indicates that the total axial force generated by external burning depends on the total amount of energy input and is independent of the transverse and streamwise distribution of heat addition. Good agreement between the Euler and control volume analysis is demonstrated. Features of the inviscid external burning flowfield are discussed. Most notably, a strong compression forms at the sonic line within the burning stream which may induce separation of the plume and prevent realization of the full performance potential. An experimental program was conducted in a Mach 1.26 free-jet to demonstrate drag reduction on a simple expansion ramp geometry, and verify hydrogen-air stability limits at external burning conditions. Stable combustion appears feasible to Mach number of between 1.4 and 2 depending on the vehicle flight trajectory. Drag reduction is demonstrated on the expansion ramp at Mach 1.26; however, force levels showed little dependence on fuel pressure or altitude in contrast to control volume analysis predictions. Various facility interference mechanisms and scaling issues were studied and are discussed.

Skin analysis following dermal exposure to kerosene in rats: the effects of postmortem exposure and fire.

PubMed

Hieda, Yoko; Tsujino, Yoshio; Xue, Yuying; Takayama, Koji; Fujihara, Junko; Kimura, Kojiro; Dekio, Satoshi

2004-02-01

To evaluate the usefulness of skin analysis for the forensic examination of cases involving postmortem dermal exposure to kerosene and/or fire, an experimental study using rats was performed. Rats received dermal exposure to kerosene before or after death, and the effect of fire was determined by burning an area of exposed skin after death. Kerosene concentrations in skin and blood were determined by gas chromatography-mass spectrometry and microscopic observation was performed for skin samples. No differences were observed in skin kerosene levels between antemortem and postmortem exposure. Kerosene concentrations in mildly burned skin where the stratum corneum (SC) was retained were approximately 84% compared to those in non-burned exposed skin, whereas concentrations in severely burned skin where the SC was almost completely burned off were 28% of non-burned skin. Even in non-exposed control skin 14% of the original kerosene concentrations could be detected, which was considered to be caused by contamination during the experimental protocol combined with kerosene's property of a high affinity for the SC. These results suggest that (1) skin analysis is useful in estimating the type of petroleum product involved in crimes or accidents even for postmortem exposure, (2) whether the SC is retained or not primarily determined the kerosene levels in burned skin, and (3) attention must be paid to evaluate the results obtained from skin samples in the light of the circumstances surrounding the case.

THz Imaging of Skin Burn: Seeing the Unseen—An Overview

PubMed Central

Dutta, Moumita; Bhalla, Amar S.; Guo, Ruyan

2016-01-01

Significance: This review article puts together all the studies performed so far in realizing terahertz (THz) spectra as a probing mechanism for burn evaluation, summarizing their experimental conditions, observations, outcomes, merits, and demerits, along with a comparative discussion of other currently used technologies to present the state of art in a condensed manner. The key features of this noncontact investigation technique like its precise burn depth analysis and the approaches it follows to convert the probed data into a quantitative measure have also been discussed in this article. Recent Advances: The current research developments in THz regime observed in device design technologies (like THz time domain spectrometer, quantum cascade THz lasers, THz single-photon detectors, etc.) and in understanding its unique properties (like nonionizing nature, penetrability through dry dielectrics, etc.) have motivated the research world to realize THz window as a potential candidate for burn detection. Critical Issues: Application of appropriate medical measure for burn injury is primarily subjective to proper estimation of burn depth. Tool modality distinguishing between partial and full-thickness burn contributing toward correct medical care is indeed awaited. Future Directions: The overview of THz imaging as a burn assessment tool as provided in this article will certainly help in further nurturing of this emerging diagnostic technique particularly in improving its detection and accompanied image processing methods so that the minute nuances captured by the THz beam can be correlated with the physiological–anatomical changes in skin structures, caused by burn, for better sensitivity, resolution, and quantitative analysis. PMID:27602253

THz Imaging of Skin Burn: Seeing the Unseen-An Overview.

PubMed

Dutta, Moumita; Bhalla, Amar S; Guo, Ruyan

2016-08-01

Significance: This review article puts together all the studies performed so far in realizing terahertz (THz) spectra as a probing mechanism for burn evaluation, summarizing their experimental conditions, observations, outcomes, merits, and demerits, along with a comparative discussion of other currently used technologies to present the state of art in a condensed manner. The key features of this noncontact investigation technique like its precise burn depth analysis and the approaches it follows to convert the probed data into a quantitative measure have also been discussed in this article. Recent Advances: The current research developments in THz regime observed in device design technologies (like THz time domain spectrometer, quantum cascade THz lasers, THz single-photon detectors, etc.) and in understanding its unique properties (like nonionizing nature, penetrability through dry dielectrics, etc.) have motivated the research world to realize THz window as a potential candidate for burn detection. Critical Issues: Application of appropriate medical measure for burn injury is primarily subjective to proper estimation of burn depth. Tool modality distinguishing between partial and full-thickness burn contributing toward correct medical care is indeed awaited. Future Directions: The overview of THz imaging as a burn assessment tool as provided in this article will certainly help in further nurturing of this emerging diagnostic technique particularly in improving its detection and accompanied image processing methods so that the minute nuances captured by the THz beam can be correlated with the physiological-anatomical changes in skin structures, caused by burn, for better sensitivity, resolution, and quantitative analysis.

Landscape Patterns of Burn Severity in the Soberanes Fire of 2016

NASA Technical Reports Server (NTRS)

Potter, Christopher

2016-01-01

The Soberanes Fire started on July 22, 2016 in Monterey County on the California Central Coast from an illegal campfire. This fire burned for 10 weeks at a record cost of more than $208 million for protection and control. A progressive analysis of the normalized burn ratio from the Landsat satellite showed that the final high burn severity (HBS) area for the Soberanes Fire comprised 22 percent of the total area burned, whereas final moderate burn severity (MBS) area comprised about 10 percent of the total area burned of approximately 53,470 ha (132,130 acres). The resulting landscape pattern of burn severity classes from the 2016 Soberanes Fire revealed that the majority of HBS area was located in the elevation zone between 500 and 1000 m, in the slope zone between 15 percent and 30 percent, or on south-facing aspects.

Compact X-ray Binary Re-creation in Core Collapse: NGC 6397

NASA Astrophysics Data System (ADS)

Grindlay, J. E.; Bogdanov, S.; van den Berg, M.; Heinke, C.

2005-12-01

We report new Chandra observations of the core collapsed globular cluster NGC 6397. In comparison with our original Chandra observations (Grindlay et al 2001, ApJ, 563, L53), we now detect some 30 sources (vs. 20) in the cluster. A new CV is confirmed, though new HST/ACS optical observations (see Cohn et al this meeting) show that one of the original CV candidates is a background AGN). The 9 CVs (optically identified) yet only one MSP and one qLMXB suggest either a factor of 7 reduction in NSs/WDs vs. what we find in 47Tuc (see Grindlay 2005, Proc. Cefalu Conf. on Interacting Binaries) or that CVs are produced in the core collapse. The possible second MSP with main sequence companion, source U18 (see Grindlay et al 2001) is similar in its X-ray and optical properties to MSP-W in 47Tuc, which must have swapped its binary companion. Together with the one confirmed (radio) MSP in NGC 6397, with an evolved main sequence secondary, the process of enhanced partner swapping in the high stellar density of core collapse is implicated. At the same time, main sequence - main sequence binaries (active binaries) are depleted in the cluster core, presumably by "binary burning" in core collapse. These binary re-creation and destruction mechanisms in core collapse have profound implications for binary evolution and mergers in globulars that have undergone core collapse.

Retrospective analysis of patients with burn injury treated in a burn center in Turkey during the Syrian civil war

PubMed Central

Yuce, Yucel; Acar, Hakan A.; Erkal, Kutlu H.; Arditi, Nur B.

2017-01-01

Objectives: To report the management of burn injuries that occured in the Syria civil war, which were referred to our burn center. Methods: Forty-three patients with burns, injured in the civil war in Syria and whom were referred to Dr. Lütfi Kırdar Kartal Educating and Training Hospital Burn Centre of İstanbul, Turkey between 2011-2015 were analyzed in a retrospective study. Results: Most of our patients were in major burn classification (93%; 40/43) and most of them had burns >15% total on body surface area. Most of them were admitted to our center late after first management at centers with improper conditions and in cultures of these patients unusual and resistant strains specific to the battlefield were produced. Conclusion: Immediate transfer of the patients from the scene of incidence to burn centers ensures early treatment, this factor may be effective on the outcome of these patients. PMID:28042637

Retrospective analysis of patients with burn injury treated in a burn center in Turkey during the Syrian civil war.

PubMed

Yuce, Yucel; Acar, Hakan A; Erkal, Kutlu H; Arditi, Nur B

2017-01-01

To report the management of burn injuries that occured in the Syria civil war, which were referred to our burn center. Methods: Forty-three patients with burns, injured in the civil war in Syria and whom were referred to Dr. Lütfi Kırdar Kartal Educating and Training Hospital Burn Centre of İstanbul, Turkey between 2011-2015 were analyzed in a retrospective study. Results: Most of our patients were in major burn classification (93%; 40/43) and most of them had burns greater than 15% total on body surface area. Most of them were admitted to our center late after first management at centers with improper conditions and in cultures of these patients unusual and resistant strains specific to the battlefield were produced. Conclusion: Immediate transfer of the patients from the scene of incidence to burn centers ensures early treatment, this factor may be effective on the outcome of these patients.

Proposing "the burns suite" as a novel simulation tool for advancing the delivery of burns education.

PubMed

Sadideen, Hazim; Wilson, David; Moiemen, Naiem; Kneebone, Roger

2014-01-01

Educational theory highlights the importance of contextualized simulation for effective learning. We explored this concept in a burns scenario in a novel, low-cost, high-fidelity, portable, immersive simulation environment (referred to as distributed simulation). This contextualized simulation/distributed simulation combination was named "The Burns Suite" (TBS). A pediatric burn resuscitation scenario was selected after high trainee demand. It was designed on Advanced Trauma and Life Support and Emergency Management of Severe Burns principles and refined using expert opinion through cognitive task analysis. TBS contained "realism" props, briefed nurses, and a simulated patient. Novices and experts were recruited. Five-point Likert-type questionnaires were developed for face and content validity. Cronbach's α was calculated for scale reliability. Semistructured interviews captured responses for qualitative thematic analysis allowing for data triangulation. Twelve participants completed TBS scenario. Mean face and content validity ratings were high (4.6 and 4.5, respectively; range, 4-5). The internal consistency of questions was high. Qualitative data analysis revealed that participants felt 1) the experience was "real" and they were "able to behave as if in a real resuscitation environment," and 2) TBS "addressed what Advanced Trauma and Life Support and Emergency Management of Severe Burns didn't" (including the efficacy of incorporating nontechnical skills). TBS provides a novel, effective simulation tool to significantly advance the delivery of burns education. Recreating clinical challenge is crucial to optimize simulation training. This low-cost approach also has major implications for surgical education, particularly during increasing financial austerity. Alternative scenarios and/or procedures can be recreated within TBS, providing a diverse educational immersive simulation experience.

A human-driven decline in global burned area

NASA Astrophysics Data System (ADS)

Andela, N.; Morton, D. C.; Chen, Y.; van der Werf, G.; Giglio, L.; Kasibhatla, P. S.; Randerson, J. T.

2016-12-01

Fire is an important and dynamic ecosystem process that influences many aspects of the global Earth system. Here, we used several different satellite datasets to assess trends in global burned area during 1998 to 2014. Global burned area decreased by about 21.6 ± 8.5% over the period from 1998-2014, with large regional declines observed in savanna and grassland ecosystems in northern Africa, Eurasia, and South America. The decrease in burned area remained robust after removing the influence of climate (16.0 ± 6.0%), implicating human activity as a likely driver. To further investigate the mechanisms contributing to regional and global trends, we conducted several kinds of analysis, including separation of burned area into ignition and fire size components and geospatial analysis of fire trends in relationship with demographic and land use variables. We found that fire number was a more important factor contributing to burned area trends than fire size, suggesting a reduction in the use of fire for management purposes. Concurrent decreases in fire size also contributed to the trend outside of North and South America, suggesting a role for greater landscape fragmentation. From our geospatial analysis, we developed a conceptual model that incorporates a range of drivers for human-driven changes in biomass burning that can be used to guide global fire models, currently unable to reproduce these large scale recent trends. Patterns of agricultural expansion and land use intensification are likely to further contribute to declining burned area trends in future decades, with important consequences for Earth system processes mediated by surface albedo, greenhouse gas emissions, and aerosols. Our results also highlight the vulnerability of savannas and grassland to land use changes with unprecedented global scale consequences for vegetation structure and the carbon cycle.

Economics of pediatric burns.

PubMed

Bass, Michael J; Phillips, Linda G

2008-07-01

Sustaining a burn injury sets in motion a cycle of pain, disfigurement, and a search for survival. In pediatric burns, the injury extends to the parents where fear, ignorance, and helplessness forever change their lives. Pediatric burn injuries are caused by fire, hot liquids, clothing irons, hair curlers, caustic substances like drain cleaner, the grounding of an electrical source, and exposure to radiation. Efficiency in the delivery of pediatric burn care is critical. Maximizing resource utilization means continual self-evaluation and economic analysis of therapeutic modalities. Griffiths et al found that most childhood burns are due to scalds, which can be treated for $1061 per percent burn. Paddock et al reduced the cost of treating superficial pediatric burns and reduced the length of stay in hospital using silver-impregnated gauze over traditional methods. Barrett et al found improved cosmesis of skin grafts using cultured epithelial autografts but at a substantially increased cost. Corpron et al showed that pediatric burn units that treat burns >10% total body surface area and operative treatment of pediatric burns regardless of size generate positive revenue. There is a paucity of evidentiary pediatric burn economic data. More research is needed to address areas of pediatric burn care inefficiency. Improving knowledge of cost in all health care endeavors will create competition and drive down expenditures.

Carbon Transfers and Emissions Following Harvest and Pile Burning in Coastal Douglas-fir Forests Determined from Analysis of High-Resolution UAV Imagery and Point Clouds and from Field Surveys.

NASA Astrophysics Data System (ADS)

Trofymow, J. A.; Gougeon, F.; Kelley, J. W.

2017-12-01

Forest carbon (C) models require knowledge on C transfers due to intense disturbances such as fire, harvest, and slash burning. In such events, live trees die and C transferred to detritus or exported as round wood. With burning, live and detrital C is lost as emissions. Burning can be incomplete, leaving wood, charred and scattered or in unburnt rings and piles. For harvests, all round wood volume is routinely measured, while dispersed and piled residue volumes are typically assessed in field surveys, scaled to a block. Recently, geospatial methods have been used to determine, for an entire block, piled residues using LiDAR or image point clouds (PC) and dispersed residues by analysis of high-resolution imagery. Second-growth Douglas-fir forests on eastern Vancouver Island were examined, 4 blocks at Oyster River (OR) and 2 at Northwest Bay (NB). OR blocks were cut winter 2011, piled spring 2011, field survey, aerial RGB imagery and LiDAR PC acquired fall 2011, piles burned, burn residues surveyed, and post-burn aerial RGB imagery acquired 2012. NB blocks were cut fall 2014, piled spring 2015, field survey, UAV RGB imagery and image PC acquired summer 2015, piles burned and burn residues surveyed spring 2016, and post-burn UAV RGB imagery and PC acquired fall 2016. Volume to biomass conversion used survey species proportions and wood density. At OR, round wood was 261.7 SE 13.1, firewood 1.7 SE 0.3, and dispersed residue by survey, 13.8 SE 3.6 tonnes dry mass (t dm) ha-1. Piled residues were 8.2 SE 0.9 from pile surveys vs. 25.0 SE 5.9 t dm ha-1 from LiDAR PC bulk pile volumes and packing ratios. Post-burn, piles lost 5.8 SE 0.5 from survey of burn residues vs. 18.2 SE 4.7 t dm ha-1 from pile volume changes using 2011 LiDAR PC and 2012 imagery. The percentage of initial merchantable biomass exported as round & fire wood, remaining as dispersed & piled residue, and lost to burning was, respectively, 92.5%, 5.5% and 2% using only field methods vs. 87%, 7% and 6% from dispersed residues surveys and LIDAR PC pile volumes. At NB, preliminary analysis shows the post-burn difference in 2015 to 2016 UAV PC pile volumes, was similar to that using 2015 UAV PC pile volume and 2016 orthophoto pile area burned, suggesting the two geospatial methods are comparable. Comparisons will be made for transfers in all 6 blocks using only field survey or geospatial methods.

Impact of New Nuclear Data Libraries on Small Sized Long Life CANDLE HTGR Design Parameters

NASA Astrophysics Data System (ADS)

Liem, Peng Hong; Hartanto, Donny; Tran, Hoai Nam

2017-01-01

The impact of new evaluated nuclear data libraries (JENDL-4.0, ENDF/B-VII.0 and JEFF-3.1) on the core characteristics of small-sized long-life CANDLE High Temperature Gas-Cooled Reactors (HTGRs) with uranium and thorium fuel cycles was investigated. The most important parameters of the CANDLE core characteristics investigated here covered (1) infinite multiplication factor of the fresh fuel containing burnable poison, (2) the effective multiplication factor of the equilibrium core, (3) the moving velocity of the burning region, (4) the attained discharge burnup, and (5) the maximum power density. The reference case was taken from the current JENDL-3.3 results. For the uranium fuel cycle, the impact of the new libraries was small, while significant impact was found for thorium fuel cycle. The findings indicated the needs of more accurate nuclear data libraries for nuclides involved in thorium fuel cycle in the future.

Convective overshooting in the evolution of very massive stars

NASA Technical Reports Server (NTRS)

Stothers, R.; Chin, C.-W.

1981-01-01

Possible convective overshooting in stars of 30-120 solar masses are considered, including a merger between the convective core and the intermediate zone, and penetration by the outer convection zone into the hydrogen-shell region when the star is a supergiant. Convective mixing between the core and inner envelopes is found to lead to a brief renewal of hydrogen burning in the core, and a moderate widening of the main sequence bond in the H-R diagram. Deep penetration by the outer convection zone is found to force the star out of the red supergiant configuration and into a configuration near the main sequence. This would account for the apparent spread of the uppermost part of the main sequence and the concentration of luminous supergiants towards earlier spectral types. In addition, heavy mass loss need not be assumed to achieve the points of agreement, and are tentatively considered unimportant from an evolutionary point of view.

Ten-year epidemiology of chemical burns in western Zhejiang Province, China.

PubMed

Ye, Chunjiang; Wang, Xingang; Zhang, Yuanhai; Ni, Liangfang; Jiang, Ruiming; Liu, Liping; Han, Chunmao

2016-05-01

Chemical burns occur frequently in western Zhejiang Province. This study documents the epidemiology of chemical burns in the region using burn data from a local specialized hospital. Results from this analysis will assist in the planning of prevention strategies for high-risk occupations and groups. A 10-year retrospective analysis was conducted for all patients with chemical burns admitted to the Department of Burn and Plastic Surgery from January 2004 to December 2013. Information obtained for each patient included demographics (gender, age, occupation and education), location of the burn, cause of the burn, and categories of chemicals. Data regarding the season of admittance, prehospital treatment, wound site/size (area, region, and depth), accompanying injuries, operations, length of hospital stay and mortality were also assessed. A total of 690 patients (619 males, 71 females; average age: 30.6±12.4 years) were admitted to the department for chemical burns. Over the 10-year period, the incidence of chemical burns showed an increasing tendency. Chemical burns occurred most frequently in patients aged 20-59 years (94.79%). Most of the chemical burns were work-related, primarily in private enterprises (47.97%) and state-owned enterprises (24.93%). Operations (68.99%) and machine problems (17.26%) were the main causes of chemical burns in the workplace. With regard to burns caused by chemicals, most were caused by acids (72.01%), with hydrofluoric acid and sulphuric acid causing 51.45%. Most chemical burns occurred in the summer and autumn seasons (61.02%). The burn size was <10% of the total body surface area (TBSA) for 445 patients (64.49%), while only 26 patients (3.76%) had burns covering >40% TBSA. The most common burn sites were the upper extremities (31.57%), lower extremities (19.86%), and head and neck (28.83%). Most patients (581 (84.20%)) received water washing treatment on site immediately after exposure. The most common accompanying injuries included inhalation injury, ocular burns and digestive tract injury. The average hospital stay was 17.0±23.1 days (range 1-333 days). Surgery was performed in 146 patients (21.16%), and the overall mortality rate was 0.58%. Chemical burns are preventable. The high morbidity of chemical burns in western Zhejiang Province is related to the industrial structure of the area. Governmental management in the fields of production, transportation, and utilization of chemicals could be improved. Workplaces have the responsibility to provide safe work environments and equipment, as well as occupational education and safety training for high-risk work groups. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Soil and Nutrient Loss Following Site Preparation Burning

Treesearch

J.P. Field; E.A. Carter

2000-01-01

Sediment loss and nutrient cpncentrations in runoff were evaluated to determine the effects of site preparation burning on a recently harvested loblolly pine (Pinus taeda L.) site in east Texas. Sediment and nutrient losses prior to treatment were approximately the same from control plots and pretreatment burn plots. Nutrient analysis of runoff...

Soil and nutrient loss following site preparation burning

Treesearch

J.P. Field; K.W. Farrish; E.A. Carter

2000-01-01

Sediment loss and nutrient cpncentrations in runoff were evaluated to determine the effects of site preparation burning on a recently harvested loblolly pine (Pinur taeda L.) site in east Texas. Sediment and nutrient losses prior to treatment were approximately the same from control plots and pretreatment burn plots. Nutrient analysis of runoff...

Femoral venous access is safe in burned children: an analysis of 224 catheters.

PubMed

Goldstein, A M; Weber, J M; Sheridan, R L

1997-03-01

To document the incidence of septic and mechanical complications associated with femoral venous catheters in a subgroup of patients thought to be at particularly high risk of both: young children with large burns. An analysis of data collected prospectively on all femoral venous catheters placed during a 4-year period at a regional pediatric burn facility. There were 224 femoral catheters placed in 86 children with an average age of 5.3 +/- 5.1 years and an average burn size of 38% +/- 23%. Catheters were left in place for a mean duration of 5.7 days. Catheter-related sepsis occurred with 4.9% of the catheters, and mechanical complications occurred in 3.5% of the patients. There was no statistically significant association between the risk of catheter sepsis and the placement of catheters through burned versus unburned skin. Similarly, the risk of sepsis was equivalent between lines placed over a guide wire and those placed of a new site. Femoral venous catheters are safe in burned children and are associated with a low incidence of infectious and mechanical complications.

Epidermal aquaporin-3 is increased in the cutaneous burn wound

PubMed Central

Sebastian, R.; Chau, E.; Fillmore, P.; Matthews, J.; Price, L.A.; Sidhaye, V.; Milner, S.M.

2018-01-01

Introduction Aquaporins (AQP) are a family of transmembrane proteins that transport water and small solutes such as glycerol across cell membranes. It is a mediator of transcellular water flow and plays an important role in maintaining intra/extracellular fluid homeostasis by facilitating water transport in response to changing osmotic gradients. In the skin, AQPs permit rapid, regulated, and selective water permeability and have been demonstrated to play a role in skin hydration, cell proliferation, migration, immunity, and wound healing. However, the expression of AQP-3 in the cutaneous burn wound has never been elucidated. We sought to assess the expression of AQP-3 in patients with burn wounds. Methods A fresh full thickness biopsy sample was taken from the center of the burn wound, the burn wound edge, and the graft donor site in 7 patients (n = 21), approximately 3–7 days post injury. Fixed, paraffin embedded sections were stained using AQP-3 specific antibody and examined by immunofluorescence. Fresh samples were processed to quantify AQP-3 protein expression with Western blot analysis. Results The central portion of the burn wound revealed destruction of the epidermis and dermis with no AQP-3 present. Along the burn wound edge where the epidermal architecture was disrupted, there was robust AQP-3 staining. Western blot analysis demonstrated deeper staining along the burn wound edge compared to unburned skin (control). Quantification of the protein shows a significant amount of AQP-3 expression along the burn wound edge (3.6 ± 0.34) compared to unburned skin (2.1 ± 0.28, N = 7, *p < 0.05). There is no AQP-3 expression in the burn wound center. Conclusion AQP-3 expression is increased in the burn wound following injury. While its role in wound healing has been defined, we report for the first time the effect of cutaneous burns on AQP-3 expression. Our data provides the first step in determining its functional role in burn wounds. We hypothesize that development of AQP3 targeted therapies may improve burn wound healing. PMID:25603981

Should Kids Be Allowed to Burn the House Down? Interrogating the Role of Ideology and Critical Pedagogy in the Drama Classroom.

ERIC Educational Resources Information Center

Alrutz, Megan

The question of how to provide children with a set of core values and beliefs, while still allowing them freedom of choice or independence, permeates not only the family structure, but the education system as well. The educator/author of this paper, a teaching artist, justifies drama as promoting critical understanding and enhancing the ability to…

Kinetic studies of ICF implosions

DOE PAGES

Kagan, Grigory; Herrmann, H. W.; Kim, Y. -H.; ...

2016-05-26

Here, kinetic effects on inertial confinement fusion have been investigated. In particular, inter-ion-species diffusion and suprathermal ion distribution have been analyzed. The former drives separation of the fuel constituents in the hot reacting core and governs mix at the shell/fuel interface. The latter underlie measurements obtained with nuclear diagnostics, including the fusion yield and inferred ion burn temperatures. Basic mechanisms behind and practical consequences from these effects are discussed.

Hybrid Architectures for Evolutionary Computing Algorithms

DTIC Science & Technology

2008-01-01

other EC algorithms to FPGA Core Burns P1026/MAPLD 200532 Genetic Algorithm Hardware References S. Scott, A. Samal , and S. Seth, “HGA: A Hardware Based...on Parallel and Distributed Processing (IPPS/SPDP 󈨦), pp. 316-320, Proceedings. IEEE Computer Society 1998. [12] Scott, S. D. , Samal , A., and...Algorithm Hardware References S. Scott, A. Samal , and S. Seth, “HGA: A Hardware Based Genetic Algorithm”, Proceedings of the 1995 ACM Third

The Status of Multi-Dimensional Core-Collapse Supernova Models

NASA Astrophysics Data System (ADS)

Müller, B.

2016-09-01

Models of neutrino-driven core-collapse supernova explosions have matured considerably in recent years. Explosions of low-mass progenitors can routinely be simulated in 1D, 2D, and 3D. Nucleosynthesis calculations indicate that these supernovae could be contributors of some lighter neutron-rich elements beyond iron. The explosion mechanism of more massive stars remains under investigation, although first 3D models of neutrino-driven explosions employing multi-group neutrino transport have become available. Together with earlier 2D models and more simplified 3D simulations, these have elucidated the interplay between neutrino heating and hydrodynamic instabilities in the post-shock region that is essential for shock revival. However, some physical ingredients may still need to be added/improved before simulations can robustly explain supernova explosions over a wide range of progenitors. Solutions recently suggested in the literature include uncertainties in the neutrino rates, rotation, and seed perturbations from convective shell burning. We review the implications of 3D simulations of shell burning in supernova progenitors for the `perturbations-aided neutrino-driven mechanism,' whose efficacy is illustrated by the first successful multi-group neutrino hydrodynamics simulation of an 18 solar mass progenitor with 3D initial conditions. We conclude with speculations about the impact of 3D effects on the structure of massive stars through convective boundary mixing.

The Two Components of the Evolved Massive Binary LZ Cephei: Testing the Effects of Binarity on Stellar Evolution

NASA Technical Reports Server (NTRS)

Mahy, L.; Martins, F.; Donati, J.-F.; Bouret, J.-C.

2011-01-01

We present an in-dep(h study of the two components of the binary system LZ Cep to constrain the effects of binarity on the evolution of massive stars. Methods. We analyzed a set of high-resolution, high signal-to-noise ratio optical spectra obtained over the orbital period of the system to perform a spectroscopic disentangling and derive an orbital solution. We subsequently determine the stellar properties of each component by means of an analysis with the CMFGEN atmosphere code. Finally, with the derived stellar parameters, we model the Hipparcos photometric light curve using the program NIGHTFALL to obtain the orbit inclination and the stellar masses. Results.LZ Cep is a O9III+ON9.7V binary. It is as a semi-detailed system in which either the primary or the secondary star almost fills up its Roche lobe. The dynamical masses are about 16.0 Stellar Mass (primary) and 6.5 Stellar Mass (secondary). The latter is lower than the typical mass of late-type O stars. The secondary component is chemically more evolved than the primary (which barely shows any sign of CNO processing), with strong helium and nitrogen enhancements as well as carbon and oxygen depletions. These properties (surface abundances and mass) are typical of Wolf-Rayet stars, although the spectral type is ON9.7V. The luminosity of the secondary is consistent with that of core He-burning objects. The preferred, tentative evolutionary scenario to explain abe observed properties involves mass transfer from the secondary - which was initially more massive- towards the primary. The secondary is now almost a core He-burning object, probably with only a thin envelope of H-rich and CNO processed material. A very inefficient mass transfer is necessary to explain the chemical appearance of the primary. Alternative scenarios are discussed but they are affected by greater uncertainties.

The two components of the evolved massive binary LZ Cephei. Testing the effects of binarity on stellar evolution

NASA Astrophysics Data System (ADS)

Mahy, L.; Martins, F.; Machado, C.; Donati, J.-F.; Bouret, J.-C.

2011-09-01

Aims: We present an in-depth study of the two components of the binary system LZ Cep to constrain the effects of binarity on the evolution of massive stars. Methods: We analyzed a set of high-resolution, high signal-to-noise ratio optical spectra obtained over the orbital period of the system to perform a spectroscopic disentangling and derive an orbital solution. We subsequently determine the stellar properties of each component by means of an analysis with the CMFGEN atmosphere code. Finally, with the derived stellar parameters, we model the Hipparcos photometric light curve using the program NIGHTFALL to obtain the orbit inclination and the stellar masses. Results: LZ Cep is a O 9III+ON 9.7V binary. It is as a semi-detached system in which either the primary or the secondary star almost fills up its Roche lobe. The dynamical masses are about 16.0 M⊙ (primary) and 6.5 M⊙ (secondary). The latter is lower than the typical mass of late-type O stars. The secondary component is chemically more evolved than the primary (which barely shows any sign of CNO processing), with strong helium and nitrogen enhancements as well as carbon and oxygen depletions. These properties (surface abundances and mass) are typical of Wolf-Rayet stars, although the spectral type is ON 9.7V. The luminosity of the secondary is consistent with that of core He-burning objects. The preferred, tentative evolutionary scenario to explain the observed properties involves mass transfer from the secondary - which was initially more massive- towards the primary. The secondary is now almost a core He-burning object, probably with only a thin envelope of H-rich and CNO processed material. A very inefficient mass transfer is necessary to explain the chemical appearance of the primary. Alternative scenarios are discussed but they are affected by greater uncertainties.

Pattern of burn injury at north of Jordan.

PubMed

Bataineh, Ziad A; Al Quran, Thekraiat M; Al Balas, Hamzeh; Khammash, Muhmammad R

2018-01-01

To the best of our knowledge, pattern of burn injury was not reported yet at our region, our hospital considered the only tertiary referral center with the only burn unit at the region since 2001 till date, a retrospective analysis of our computerized filing system recorded 527 burn patients between 2001-2016, mean age was 26 years; 1.27:1 was the male to female ratio, 79 patients were found to have major burns, 46% of admissions were below 20 years' age, 92% was at domestic site of affection and 65% due to flame burn followed by scald burn in about 23%. The limbs were the most affected body site, majority of patients were below 15% TBSA and partial thickness, 77 patients found to have inhalational injury. Our mean hospital stay was 16 days and mortality was 8.2%. Mortality was associated with high TBSA affection, depth and flame type. This study shows the pattern of burn at north of Jordan, preventive measures by education and observation will reduce the incidence of burn and its sequel, non-flammable cook plates and stoves will probably help in decrease burn morbidity and mortality.

The effects of rapid enzymatic debridement of deep partial-thickness burns with Debrase on wound reepithelialization in swine.

PubMed

Singer, Adam J; Taira, Breena R; Anderson, Ryon; McClain, Steve A; Rosenberg, Lior

2010-01-01

Reepithelialization of deep burns requires spontaneous or active removal or debridement of the necrotic eschar, as recently defined by the American Burn Association. Debrase is a bromelain-derived enzymatic preparation that has been shown to result in rapid and selective debridement of human and animal burns. The authors hypothesized that rapid debridement of deep dermal burns with Debrase would result in earlier reepithelialization of the remaining dermis in a porcine model. Eighty deep dermal contact burns measuring 10 by 20 mm were created on the back and flanks of anesthetized domestic pigs (25 kg) using a brass template preheated in boiling water (100 degrees C) that was applied to the skin for a period of 30 seconds. The template was applied using a spring-loaded device designed to control the amount of pressure applied to the skin by the template. Burns were randomized to a 4-hour topical application of Debrase (lyophilized dry enzyme dissolved and activated in a hydrating vehicle) (n = 40) or its hydrating vehicle (n = 40) followed by daily application of a petrolatum-based antibiotic ointment. Wounds were visually assessed and photographed daily. Four-millimeter full-thickness punch biopsies were obtained for histological analysis using hematoxylin and eosin staining by a board-certified dermatopathologist masked to burn therapy at 7, 11, 13, and 15 days after injury. The primary outcome was the percentage of the burns that were completely reepithelialized at each time point. Secondary outcomes were time to complete reepithelialization and the mean percentage of reepithelialization on microscopic analysis. A sample of 40 burns in each group had 80% power to detect a 20% difference in the percentage of completely reepithelialized burns (two tailed, P < .05). The percentage of completely reepithelialized burns was higher for Debrase than control burns at days 11 (40.9% vs 3.1%; P = .002), 13 (87.5% vs 50%; P = .007), and 15 (97.5% vs 77.5%, P = .018). The mean (SD) percentage reepithelialization of Debrase-treated burns at 7 days was higher than of control burns (47.6% [3.2] vs 0% [0]; P < .001). A larger number of cells in the epidermis and dermis of debrided burns stained positive for the proliferation antigen Ki-67. There was no evidence of any adverse events in the normal skin adjacent to the Debrase-treated burns. Rapid enzymatic debridement of deep partial-thickness burns with Debrase results in earlier reepithelialization and cellular proliferation in swine, when compared with carrier and topical antibiotic dressings alone.

Newspaper reporting and the emergence of charcoal burning suicide in Taiwan: A mixed methods approach.

PubMed

Chen, Ying-Yeh; Tsai, Chi-Wei; Biddle, Lucy; Niederkrotenthaler, Thomas; Wu, Kevin Chien-Chang; Gunnell, David

2016-03-15

It has been suggested that extensive media reporting of charcoal burning suicide was a key factor in the rapid spread of this novel method in many East Asian countries. But very few empirical studies have explored the relationship between media reporting and the emergence of this new method of suicide. We investigated the changing pattern of media reporting of charcoal burning suicides in Taiwan during 1998-2002 when this method of suicide increased most rapidly, assessing whether the characteristics of media reporting were associated with the changing incidence of suicide using this method. A mixed method approach, combining quantitative and qualitative analysis of newspaper content during 1998-2002 was used. We compared differences in reporting characteristics before and after the rapid increase in charcoal burning suicide. Point-biserial and Pearson correlation coefficients were calculated to quantify the associations between the media item content and changes in suicide rates. During the period when charcoal burning suicide increased rapidly, the number of reports per suicide was considerably higher than during the early stage (0.31 vs. 0.10). Detailed reporting of this new method was associated with a post-reporting increase in suicides using the method. Qualitative analysis of news items revealed that the content of reports of suicide by charcoal burning changed gradually; in the early stages of the epidemic (1999-2000) there was convergence in the terminology used to report charcoal burning deaths, later reports gave detailed descriptions of the setting in which the death occurred (2001) and finally the method was glamourized and widely publicized (2001-2002). Our analysis was restricted to newspaper reports and did not include TV or the Internet. Newspaper reporting was associated with the evolution and establishment of charcoal burning suicide. Working with media and close monitoring of changes in the incidence of suicide using a new method might help prevent a suicide epidemic such as charcoal burning suicide seen in Taiwan. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel burn device for rapid, reproducible burn wound generation.

PubMed

Kim, J Y; Dunham, D M; Supp, D M; Sen, C K; Powell, H M

2016-03-01

Scarring following full thickness burns leads to significant reductions in range of motion and quality of life for burn patients. To effectively study scar development and the efficacy of anti-scarring treatments in a large animal model (female red Duroc pigs), reproducible, uniform, full-thickness, burn wounds are needed to reduce variability in observed results that occur with burn depth. Prior studies have proposed that initial temperature of the burner, contact time with skin, thermal capacity of burner material, and the amount of pressure applied to the skin need to be strictly controlled to ensure reproducibility. The purpose of this study was to develop a new burner that enables temperature and pressure to be digitally controlled and monitored in real-time throughout burn wound creation and compare it to a standard burn device. A custom burn device was manufactured with an electrically heated burn stylus and a temperature control feedback loop via an electronic microstat. Pressure monitoring was controlled by incorporation of a digital scale into the device, which measured downward force. The standard device was comprised of a heat resistant handle with a long rod connected to the burn stylus, which was heated using a hot plate. To quantify skin surface temperature and internal stylus temperature as a function of contact time, the burners were heated to the target temperature (200±5°C) and pressed into the skin for 40s to create the thermal injuries. Time to reach target temperature and elapsed time between burns were recorded. In addition, each unit was evaluated for reproducibility within and across three independent users by generating burn wounds at contact times spanning from 5 to 40s at a constant pressure and at pressures of 1 or 3lbs with a constant contact time of 40s. Biopsies were collected for histological analysis and burn depth quantification using digital image analysis (ImageJ). The custom burn device maintained both its internal temperature and the skin surface temperature near target temperature throughout contact time. In contrast, the standard burner required more than 20s of contact time to raise the skin surface temperature to target due to its quickly decreasing internal temperature. The custom burner was able to create four consecutive burns in less than half the time of the standard burner. Average burn depth scaled positively with time and pressure in both burn units. However, the distribution of burn depth within each time-pressure combination in the custom device was significantly smaller than with the standard device and independent of user. The custom burn device's ability to continually heat the burn stylus and actively control pressure and temperature allowed for more rapid and reproducible burn wounds. Burns of tailored and repeatable depths, independent of user, provide a platform for the study of anti-scar and other wound healing therapies without the added variable of non-uniform starting injury. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Novel burn device for rapid, reproducible burn wound generation

PubMed Central

Kim, J.Y.; Dunham, D.M.; Supp, D.M.; Sen, C.K.; Powell, H.M.

2016-01-01

Introduction Scarring following full thickness burns leads to significant reductions in range of motion and quality of life for burn patients. To effectively study scar development and the efficacy of anti-scarring treatments in a large animal model (female red Duroc pigs), reproducible, uniform, full-thickness, burn wounds are needed to reduce variability in observed results that occur with burn depth. Prior studies have proposed that initial temperature of the burner, contact time with skin, thermal capacity of burner material, and the amount of pressure applied to the skin need to be strictly controlled to ensure reproducibility. The purpose of this study was to develop a new burner that enables temperature and pressure to be digitally controlled and monitored in real-time throughout burn wound creation and compare it to a standard burn device. Methods A custom burn device was manufactured with an electrically heated burn stylus and a temperature control feedback loop via an electronic microstat. Pressure monitoring was controlled by incorporation of a digital scale into the device, which measured downward force. The standard device was comprised of a heat resistant handle with a long rod connected to the burn stylus, which was heated using a hot plate. To quantify skin surface temperature and internal stylus temperature as a function of contact time, the burners were heated to the target temperature (200 ± 5 °C) and pressed into the skin for 40 s to create the thermal injuries. Time to reach target temperature and elapsed time between burns were recorded. In addition, each unit was evaluated for reproducibility within and across three independent users by generating burn wounds at contact times spanning from 5 to 40 s at a constant pressure and at pressures of 1 or 3 lbs with a constant contact time of 40 s. Biopsies were collected for histological analysis and burn depth quantification using digital image analysis (ImageJ). Results The custom burn device maintained both its internal temperature and the skin surface temperature near target temperature throughout contact time. In contrast, the standard burner required more than 20 s of contact time to raise the skin surface temperature to target due to its quickly decreasing internal temperature. The custom burner was able to create four consecutive burns in less than half the time of the standard burner. Average burn depth scaled positively with time and pressure in both burn units. However, the distribution of burn depth within each time-pressure combination in the custom device was significantly smaller than with the standard device and independent of user. Conclusions The custom burn device's ability to continually heat the burn stylus and actively control pressure and temperature allowed for more rapid and reproducible burn wounds. Burns of tailored and repeatable depths, independent of user, provide a platform for the study of anti-scar and other wound healing therapies without the added variable of non-uniform starting injury. PMID:26803369

Factors affecting the depth of burns occurring in medical institutions.

PubMed

Cho, Young Soon; Choi, Young Hwan; Yoon, Cheonjae; You, Je Sung

2015-05-01

Most cases of burns occurring in medical institutions are associated with activities involving heat. It is very difficult to detect these burns. To date, there are few reports on burns occurring in medical institutions. The purpose of this paper was to analyze the etiology of burns occurring in medical institutions and to elucidate the factors affecting burn depth. We conducted a retrospective analysis of the medical records of patients who visited our center from April 2008 to February 2013. This study enrolled all patients with burns occurring in the medical institution during or related to treatment. We excluded burn patients whose burns were not related to treatment (for example, we excluded patients with scalding burns that occurred in the hospital cafeteria and pediatric patients with hot water burns from the water purifier). However, patients with burns that occurred in the recovery room after general anesthesia were included. A total of 115 patients were enrolled in this study. The average patient age was 41.5 years, with more women than men (M:F=31:84). There were 29 cases (25.3%) of superficial burns (first-degree and superficial second-degree) and 86 cases (74.7%) of deep burns (deep second-degree and third-degree). Hot packs were the most common cause of burns (27 cases, 23.5%), followed by laser therapy, heating pads, and grounding pads, accounting for 15 cases each. There were 89 cases (77.4%) of contact burns and 26 cases (22.6%) of non-contact burns. The most common site of burns was the lower extremities (41 cases, 35.7%). The burn site and contact burns were both factors affecting burn depth. The rate of deep burns was higher in patients with contact burns than in those with non-contact burns (odds ratio 4.26) and was associated with lower body burns (odds ratio 2.85). In burns occurring in medical institutions, there is a high probability of a deep burn if it is a contact burn or occurs in the lower body. Therefore, safety guidelines are needed for the use of hot packs, heating pads, and grounding pads to prevent such incidents. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Combat-related facial burns: analysis of strategic pitfalls.

PubMed

Johnson, Benjamin W; Madson, Andrew Q; Bong-Thakur, Sarah; Tucker, David; Hale, Robert G; Chan, Rodney K

2015-01-01

Burns constitute approximately 10% of all combat-related injuries to the head and neck region. We postulated that the combat environment presents unique challenges not commonly encountered among civilian injuries. The purpose of the present study was to determine the features commonly seen among combat facial burns that will result in therapeutic challenges and might contribute to undesired outcomes. The present study was a retrospective study performed using a query of the Burn Registry at the US Army Institute of Surgical Research Burn Center for all active duty facial burn admissions from October 2001 to February 2011. The demographic data, total body surface area of the burn, facial region body surface area involvement, and dates of injury, first operation, and first facial operation were tabulated and compared. A subset analysis of severe facial burns, defined by a greater than 7% facial region body surface area, was performed with a thorough medical record review to determine the presence of associated injuries. Of all the military burn injuries, 67.1% (n = 558) involved the face. Of these, 81.3% (n = 454) were combat related. The combat facial burns had a mean total body surface area of 21.4% and a mean facial region body surface area of 3.2%. The interval from the date of the injury to the first operative encounter was 6.6 ± 0.8 days and was 19.8 ± 2.0 days to the first facial operation. A subset analysis of the severe facial burns revealed that the first facial operation and the definitive coverage operation was performed at 13.45 ± 2.6 days and 31.9 ± 4.1 days after the injury, respectively. The mortality rate for this subset of patients was 32% (n = 10), with a high rate of associated inhalational injuries (61%, n = 19), limb amputations (29%, n = 9), and facial allograft usage (48%, n = 15) and a mean facial autograft thickness of 10.5/1,000th in. Combat-related facial burns present multiple challenges, which can contribute to suboptimal long-term outcomes. These challenges include prolonged transport to the burn center, delayed initial intervention and definitive coverage, and a lack of available high-quality color-matched donor skin. These gaps all highlight the need for novel anti-inflammatory and skin replacement strategies to more adequately address these unique combat-related obstacles. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. All rights reserved.

Comparison of traditional burn wound mapping with a computerized program.

PubMed

Williams, James F; King, Booker T; Aden, James K; Serio-Melvin, Maria; Chung, Kevin K; Fenrich, Craig A; Salinas, José; Renz, Evan M; Wolf, Steven E; Blackbourne, Lorne H; Cancio, Leopoldo C

2013-01-01

Accurate burn estimation affects the use of burn resuscitation formulas and treatment strategies, and thus can affect patient outcomes. The objective of this process-improvement project was to compare the accuracy of a computer-based burn mapping program, WoundFlow (WF), with the widely used hand-mapped Lund-Browder (LB) diagram. Manikins with various burn representations (from 1% to more than 60% TBSA) were used for comparison of the WF system and LB diagrams. Burns were depicted on the manikins using red vinyl adhesive. Healthcare providers responsible for mapping of burn patients were asked to perform burn mapping of the manikins. Providers were randomized to either an LB or a WF group. Differences in the total map area between groups were analyzed. Also, direct measurements of the burn representations were taken and compared with LB and WF results. The results of 100 samples, compared using Bland-Altman analysis, showed no difference between the two methods. WF was as accurate as LB mapping for all burn surface areas. WF may be additionally beneficial in that it can track daily progress until complete wound closure, and can automatically calculate burn size, thus decreasing the chances of mathematical errors.

Long-term survival after burns in a Swedish population.

PubMed

Pompermaier, Laura; Steinvall, Ingrid; Fredrikson, Mats; Thorfinn, Johan; Sjöberg, Folke

2017-02-01

As widely reported, the progress in burn care during recent decades has reduced the hospital mortality. The effect of the burns on long-term outcome has not received so much attention, and more study is indicated. The aim of this retrospective study was to investigate the long-time survival among patients who had been treated for burns. We studied 1487 patients who were discharged alive from the Linköping University Hospital Burn Centre during the period 1993 until the end of December 2012. We used Cox's regression analysis to study the effect of burns on long-term survival after adjustment for different factors. Age and a full-thickness burn were significantly associated with mortality after discharge (p<0.001), whereas percentage of total body surface area burned (TBSA %), need for mechanical ventilation, and gender were not. Less than 1% of the patients with burns (13/1487) died within 30 days of discharge and a total of 176/1487 (12%) died during follow-up. Age and full-thickness burns reduce the long-time survival after discharge from the Burn Centre, whereas the effect of TBSA% and need for artificial ventilation ends with discharge. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Assessing the spatial representability of charcoal and PAH-based paleofire records with integrated GIS, modelling, and empirical approaches

NASA Astrophysics Data System (ADS)

Vachula, R. S.; Huang, Y.; Russell, J. M.

2017-12-01

Lake sediment-based fire reconstructions offer paleoenvironmental context in which to assess modern fires and predict future burning. However, despite the ubiquity, many uncertainties remain regarding the taphonomy of paleofire proxies and the spatial scales for which they record variations in fire history. Here we present down-core proxy analyses of polycyclic aromatic hydrocarbons (PAHs) and three size-fractions of charcoal (63-150, >150 and >250 μm) from Swamp Lake, California, an annually laminated lacustrine archive. Using a statewide historical GIS dataset of area burned, we assess the spatial scales for which these proxies are reliable recorders of fire history. We find that the coherence of observed and proxy-recorded fire history inherently depends upon spatial scale. Contrary to conventional thinking that charcoal mainly records local fires, our results indicate that macroscopic charcoal (>150 μm) may record spatially broader (<25 km) changes in fire history, and as such, the coarsest charcoal particles (>250 μm) may be a more conservative proxy for local burning. We find that sub-macroscopic charcoal particles (63-150 μm) reliably record regional (up to 150 km) changes in fire history. These results indicate that charcoal-based fire reconstructions may represent spatially broader fire history than previously thought, which has major implications for our understanding of spatiotemporal paleofire variations. Our analyses of PAHs show that dispersal mobility is heterogeneous between compounds, but that PAH fluxes are reliable proxies of fire history within 25-50 km, which suggests PAHs may be a better spatially constrained paleofire proxy than sedimentary charcoal. Further, using a linear discriminant analysis model informed by modern emissions analyses, we show that PAH assemblages preserved in lake sediments can differentiate vegetation type burned, and are thus promising paleoecological biomarkers warranting further research and implementation. In sum, our analyses offer new insight into the spatial dimensions of paleofire proxies and constitute a methodology that can be applied to other locations and proxies to better inform site-specific reconstructions.

Acute mental disorders and short and long term morbidity in patients with third degree flame burn: A population-based outcome study of 96,451 patients from the Nationwide Inpatient Sample (NIS) database (2001-2011).

PubMed

Mahendraraj, Krishnaraj; Durgan, Diane M; Chamberlain, Ronald S

2016-12-01

Although burn patients with preexisting mood disorders have been shown to have diminished clinical recovery, acute mental disorders (AMD) are often unrecognized despite a link with post-traumatic stress disorder and social maladjustment later on. This study assessed the clinical profile of a large cohort of burn patients who developed AMD compared to those with chronic mental illness (CMI) and those without mental health problems to assess the impact of AMI on burn outcomes. Admission data on 96,451 patients with third degree flame burns was abstracted from the Nationwide Inpatient Sample (NIS) Database from 2001 to 2011. AMD was defined as adjustment disorder (ICD-10 codes F43.2-F43.29) and acute stress disorder (F43.0), while CMI was defined as major depressive disorder (F33.0-F33.9) and bipolar disorder (F31.0-F31.9). Data was compared across three subgroups: AMD, CMI, and patients without any mood disorders. Categorical variables were compared using the Chi-square test, and continuous variables were compared using Student t-test and analysis of variance (ANOVA). Multivariate analysis using the "backward Wald" method was performed to calculate odds ratios (OR) and determine independent factors which increased the risk of developing AMD after burn. 979 (1%) burn patients were diagnosed with AMD, compared to 5971 (6.2%) with CMI and 89,501 (92.8%) without mood disorders at the time of the burn. Patients with AMD were significantly younger, predominantly male and Caucasian. Patients with AMD had a higher frequency of multiple third-degree burn sites. AMD patients had a significantly longer length of hospitalization and shorter actuarial survival. More AMD patients lacked social or family support, suffered from alcoholism or illicit drug abuse, and had a history of psychological trauma or self-inflicted injuries compared to other groups. After burn, 4.9% of AMD patients developed burn wound infections, 5.0% had nutritional deficiencies, 1.7% had skin graft failure, 0.7% had acute psychosis, and 3.7% had suicidal ideation, p<0.05. Multivariate analysis identified age 10-39 (OR 4.6), alcoholism (OR 1.4), drug abuse (OR 1.9), psychoses (OR 1.4), and total body surface are (TBSA) 10-39% third degree burns (OR 1.8) as independently associated with developing AMD, p<0.005. The development of AMD in burn patients is associated with poor clinical outcomes including longer hospitalization, decreased survival, and increased complication rates. Premorbid psychopathology, substance abuse and age were associated with a higher incidence AMD after burn than was the severity of the burn wound itself. Routine screening for psychological symptoms of AMD should be performed in all burn patients to avoid increased rates of short and long-term morbidity and mortality. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Output-Based Adaptive Meshing Applied to Space Launch System Booster Separation Analysis

NASA Technical Reports Server (NTRS)

Dalle, Derek J.; Rogers, Stuart E.

2015-01-01

This paper presents details of Computational Fluid Dynamic (CFD) simulations of the Space Launch System during solid-rocket booster separation using the Cart3D inviscid code with comparisons to Overflow viscous CFD results and a wind tunnel test performed at NASA Langley Research Center's Unitary PlanWind Tunnel. The Space Launch System (SLS) launch vehicle includes two solid-rocket boosters that burn out before the primary core stage and thus must be discarded during the ascent trajectory. The main challenges for creating an aerodynamic database for this separation event are the large number of basis variables (including orientation of the core, relative position and orientation of the boosters, and rocket thrust levels) and the complex flow caused by the booster separation motors. The solid-rocket boosters are modified from their form when used with the Space Shuttle Launch Vehicle, which has a rich flight history. However, the differences between the SLS core and the Space Shuttle External Tank result in the boosters separating with much narrower clearances, and so reducing aerodynamic uncertainty is necessary to clear the integrated system for flight. This paper discusses an approach that has been developed to analyze about 6000 wind tunnel simulations and 5000 flight vehicle simulations using Cart3D in adaptive-meshing mode. In addition, a discussion is presented of Overflow viscous CFD runs used for uncertainty quantification. Finally, the article presents lessons learned and improvements that will be implemented in future separation databases.

Pre-hospital burn mission as a unique experience: a qualitative study.

PubMed

Froutan, Razieh; Khankeh, Hamid Reza; Fallahi, Masoud; Ahmadi, Fazlollah; Norouzi, Kian

2014-12-01

A thorough understanding of experiences related to pre-hospital emergency care of burns is a prerequisite of skill promotion for medical personnel. The aim of the present study was to evaluate the experiences of pre-hospital emergency personnel during burn accidents. The present qualitative study was performed using a content analysis method. In total, 18 Iranian emergency care personnel participated in the study. A purposeful sampling method was applied until reaching data saturation. Data were collected using semi-structured interviews and field observations. Afterwards, the gathered data were analyzed through face content analysis. By analyzing 498 primary codes, four main categories; the nature of burn care, tension at the accident scene, gradual job 'burnout', and insufficient information, were extracted from the experiences of pre-hospital emergency personnel during burn care. These categories each included several sub-categories, which were classified according to their significant characteristics. This study showed that different factors affect the quality of pre-hospital clinical services for burns. Authorities and health system administrators should consider the physical and psychological health of their staff, and assign policies to improve the quality of pre-hospital medical care. According to the present results, it is recommended that the process of pre-hospital emergency care for burns be investigated further. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Burns in South Korea: An analysis of nationwide data from the Health Insurance Review and Assessment Service.

PubMed

Oh, Hyunjin; Boo, Sunjoo

2016-05-01

The purpose of the study was to identify and describe the incidence of burn injuries in patients seen and treated in South Korea. Characteristics of inpatients and outpatients with burns were analyzed according to gender, age, burn site, and burn severity. This retrospective study examined the characteristics of a stratified sample of burn patients seen and treated in South Korea during the calendar year 2011. The sample was drawn from the national patient database Health Insurance Review and Assessment (HIRA). Approximately 1.71% of the total patients in the Patient Sample of HIRA for 2011 were burn-injured patients. The numbers of patients treated for burns were 913/10(5) males (n=8009) and 1454/10(5) females (n=11,881). Nearly all of these patients (94.1%) were covered by national health insurance and the majority of these patients (80.6%) were treated as outpatients. Nearly half of the burn injuries were of the upper extremities (43.5%), and most of these injuries (71.5%) were rated as second-degree burns. A review of the national data on patients seen and treated for burns in 2011 revealed that people in South Korea may experience higher numbers and more severe cases of burns and burn-related injuries than found in other countries. General burn prevention programs as well as gender- and age-specific prevention strategies are needed to reduce the risk of burns in this population. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Ion Thermal Decoupling and Species Separation in Shock-Driven Implosions

DOE PAGES

Rinderknecht, Hans G.; Rosenberg, M. J.; Li, C. K.; ...

2015-01-14

Here, anomalous reduction of the fusion yields by 50% and anomalous scaling of the burn-averaged ion temperatures with the ion-species fraction has been observed for the first time in D 3He-filled shock-driven inertial confinement fusion implosions. Two ion kinetic mechanisms are used to explain the anomalous observations: thermal decoupling of the D and 3He populations and diffusive species separation. The observed insensitivity of ion temperature to a varying deuterium fraction is shown to be a signature of ion thermal decoupling in shock-heated plasmas. The burn-averaged deuterium fraction calculated from the experimental data demonstrates a reduction in the average core deuteriummore » density, as predicted by simulations that use a diffusion model. Accounting for each of these effects in simulations reproduces the observed yield trends.« less

Direct radiative effect of carbonaceous aerosols from crop residue burning during the summer harvest season in East China

NASA Astrophysics Data System (ADS)

Yao, Huan; Song, Yu; Liu, Mingxu; Archer-Nicholls, Scott; Lowe, Douglas; McFiggans, Gordon; Xu, Tingting; Du, Pin; Li, Jianfeng; Wu, Yusheng; Hu, Min; Zhao, Chun; Zhu, Tong

2017-04-01

East China experiences extensive crop residue burnings in fields during harvest season. The direct radiative effect (DRE) of carbonaceous aerosols from crop residue burning in June 2013 in East China was investigated using the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem). Absorption of organic aerosol (OA) in the presence of brown carbon was considered using the parameterization of Saleh et al. (2014), in which the imaginary part of the OA refractive index is a function of wavelength and the ratio of black carbon (BC) and OA. The carbonaceous emissions from crop fires were estimated using the Moderate Resolution Imaging Spectroradiometer (MODIS) fire radiative power (FRP) product with a localized crop-burning-sourced BC-to-organic carbon (OC) ratio emission ratio of 0.27. Evaluation of the model results with in situ measurements of particulate matter with aerodynamic diameter less than 2.5 µm (PM2. 5) chemical composition, MODIS aerosol optical depth (AOD) detections and meteorological observations showed that this model was able to reproduce the magnitude, spatial variation and optical characteristics of carbonaceous aerosol pollution. The observed BC and OC peak concentrations at the site in Suixi, Anhui province, during the 2013 wheat burning season reached 55.3 µg m-3 and 157.9 µg m-3. WRF-Chem simulations reproduced these trends with a correlation coefficient of 0.74, estimating that crop residue burning contributed 86 and 90 % of peak BC and OC, respectively. The simulated hourly DRE from crop residue burning at the top of atmosphere (TOA) reached a maximum of +22.66 W m-2 at the Suixi site. On average, the simulations showed that the crop residue burning introduced a net positive DRE of +0.14 W m-2 at TOA throughout East China, with BC from this source as the main heating contributor (+0.79 W m-2). The OA DRE from crop burning (-0.22 W m-2) was a combined effect of the positive DRE of absorption (+0.21 W m-2) and a stronger negative DRE of scattering (-0.43 W m-2). Sensitivity tests showed that the DRE of OA absorption strongly depended on the imaginary part of the OA refractive index, the BC-to-OA emission ratio from crop residue burning and the assumed mixing state of the aerosol, whereby the volume mixing treatment resulted in a higher positive DRE compared to the core-shell treatment. The BC mixing state and associated absorption enhancement during BC aging processes will be investigated in detail in future research.

Differences between intentional and non-intentional burns in India: implications for prevention.

PubMed

Natarajan, Mangai

2014-08-01

Non-intentional and deliberate burns in India and other developing countries present particular challenges of prevention and treatment. This exploratory study sought improved understanding of burns in order to inform treatment and prevention. It gathered data in 2011/2012 on burns from the hospital registry (N=768) of a government hospital in India and from interviews with women patients (N=60) admitted to the burns ward. Analysis indicated that: (1) the conditions that facilitate intentional and non-intentional burns are similar, but intentional burns involve additional contributory factors; (2) a high proportion of patients subjected to burns are young women in domestic situations; and (3) a higher proportion of their TBSA was burned, with consequent higher mortality than for men. It was concluded that: (1) Haddon's matrix and the situational crime prevention framework of criminology assist in understanding the etiology of intentional burns and in identifying preventive measures; (2) social service and criminal justice agencies have important roles in dealing with victims of intentional burns during and after treatment; (3) full account should be taken of gender-related physical, psychological and family factors in planning treatment; and (4) maintaining careful records of burns cases is vital for estimating the prevalence and incidence of intentional injuries. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Predicting success of prescribed fires in pinyon-juniper woodlands in Nevada

Treesearch

Allen D. Bruner; Donald A. Klebenow

1979-01-01

Thirty prescribed burns were attempted in pinyon-juniper woodlands from fall 1974 to fall 1976. These attempts were made out of fire season, during varied atmospheric conditions, and in several pinyon-juniper communities. An analysis of the successful burns provided us with a method for predicting burning success from windspeed, air temperature, and vegetation cover....

40 CFR 63.7550 - What reports must I submit and when?

Code of Federal Regulations, 2011 CFR

2011-07-01

... this test, if applicable. (6) A signed statement indicating that you burned no new types of fuel. Or, if you did burn a new type of fuel, you must submit the calculation of chlorine input, using Equation... or process heaters that demonstrate compliance through fuel analysis). If you burned a new type of...

Soil an-d nutrient loss following site preparation burning

Treesearch

E.A. Carter; J.P. Field; K.W. Farrish

2000-01-01

Sediment loss and nutrient cpncentrations in runoff were evaluated to determine the effects of site preparation burning on a recently harvested loblolly pine (Pinur taeda L.) site in east Texas. Sediment and nutrient losses prior to treatment were approximately the same from control plots and pretreatment burn plots. Nutrient analysis of runoff samples indicated that...

Large forest fires in Canada, 1959-1997

NASA Astrophysics Data System (ADS)

Stocks, B. J.; Mason, J. A.; Todd, J. B.; Bosch, E. M.; Wotton, B. M.; Amiro, B. D.; Flannigan, M. D.; Hirsch, K. G.; Logan, K. A.; Martell, D. L.; Skinner, W. R.

2002-01-01

A Large Fire Database (LFDB), which includes information on fire location, start date, final size, cause, and suppression action, has been developed for all fires larger than 200 ha in area for Canada for the 1959-1997 period. The LFDB represents only 3.1% of the total number of Canadian fires during this period, the remaining 96.9% of fires being suppressed while <200 ha in size, yet accounts for ˜97% of the total area burned, allowing a spatial and temporal analysis of recent Canadian landscape-scale fire impacts. On average ˜2 million ha burned annually in these large fires, although more than 7 million ha burned in some years. Ecozones in the boreal and taiga regions experienced the greatest areas burned, with an average of 0.7% of the forested land burning annually. Lightning fires predominate in northern Canada, accounting for 80% of the total LFDB area burned. Large fires, although small in number, contribute substantially to area burned, most particularly in the boreal and taiga regions. The Canadian fire season runs from late April through August, with most of the area burned occurring in June and July due primarily to lightning fire activity in northern Canada. Close to 50% of the area burned in Canada is the result of fires that are not actioned due to their remote location, low values-at-risk, and efforts to accommodate the natural role of fire in these ecosystems. The LFDB is updated annually and is being expanded back in time to permit a more thorough analysis of long-term trends in Canadian fire activity.

Large forest fires in Canada, 1959-1997

NASA Astrophysics Data System (ADS)

Stocks, B. J.; Mason, J. A.; Todd, J. B.; Bosch, E. M.; Wotton, B. M.; Amiro, B. D.; Flannigan, M. D.; Hirsch, K. G.; Logan, K. A.; Martell, D. L.; Skinner, W. R.

2003-01-01

A Large Fire Database (LFDB), which includes information on fire location, start date, final size, cause, and suppression action, has been developed for all fires larger than 200 ha in area for Canada for the 1959-1997 period. The LFDB represents only 3.1% of the total number of Canadian fires during this period, the remaining 96.9% of fires being suppressed while <200 ha in size, yet accounts for ~97% of the total area burned, allowing a spatial and temporal analysis of recent Canadian landscape-scale fire impacts. On average ~2 million ha burned annually in these large fires, although more than 7 million ha burned in some years. Ecozones in the boreal and taiga regions experienced the greatest areas burned, with an average of 0.7% of the forested land burning annually. Lightning fires predominate in northern Canada, accounting for 80% of the total LFDB area burned. Large fires, although small in number, contribute substantially to area burned, most particularly in the boreal and taiga regions. The Canadian fire season runs from late April through August, with most of the area burned occurring in June and July due primarily to lightning fire activity in northern Canada. Close to 50% of the area burned in Canada is the result of fires that are not actioned due to their remote location, low values-at-risk, and efforts to accommodate the natural role of fire in these ecosystems. The LFDB is updated annually and is being expanded back in time to permit a more thorough analysis of long-term trends in Canadian fire activity.

Reduced length of stay in hospital for burn patients following a change in practice guidelines: financial implications.

PubMed

Jansen, Leigh A; Hynes, Sally L; Macadam, Sheina A; Papp, Anthony

2012-01-01

The objective of this study was to analyze the financial implications of the implementation of new institutional practice guidelines including greater outpatient care and earlier operative intervention in a provincial burn center. A retrospective review was performed including all patients admitted to the Burn Unit with burns up to 20% TBSA between August 2005 and July 2009, including 2 years before and after the new guidelines were introduced. Daily costs for the burn unit were used to calculate this portion of cost. Length of stay (LOS) was based on actual data and representative clinical scenarios. Two hundred sixty-four patients were included. Mean LOS decreased from 10.3 to 3.9 (P < .01) and 21.0 to 13.3 (P > .05) for nonoperative burns 0 to 10% and 10 to 20% TBSA, respectively. Mean LOS for operative burns decreased from 16.6 to 12.9 and 32.3 to 29.8 days for 0 to 10% and 10 to 20% TBSA, respectively (P > .05). Burn patient management requires significant financial resources, and LOS has a large impact on cost. Given per diem rates of Can$1,663, scenario analysis shows potential cost savings of Can$19,956 per patient for operative and nonoperative burns <20% TBSA. With an average of 66 such patients treated each year, potential annual cost savings are Can$1.3 million. If outcomes are not compromised, earlier operative management and greater outpatient care can translate into significant cost savings. A prospective analysis capturing all costs and patient quality of life is required for further assessment.

The evaluation of physical exam findings in patients assessed for suspected burn inhalation injury.

PubMed

Ching, Jessica A; Shah, Jehan L; Doran, Cody J; Chen, Henian; Payne, Wyatt G; Smith, David J

2015-01-01

The purpose of this investigation was to evaluate the utility of singed nasal hair (SN), carbonaceous sputum (CS), and facial burns (FB) as indicators of burn inhalation injury, when compared to the accepted standard of bronchoscopic diagnosis of inhalation injury. An institutional review board approved, retrospective review was conducted. All patients were suspected to have burn inhalation injury and subsequently underwent bronchoscopic evaluation. Data collected included: percent burn TBSA, burn injury mechanism, admission physical exam findings (SN, CS, FB), and bronchoscopy findings. Thirty-five males and twelve females met inclusion criteria (n = 47). Bronchoscopy was normal in 31 patients (66%). Data were analyzed as all patients and in subgroups according to burn TBSA and an enclosed space mechanism of injury. Physical exam findings (SN, CS, FB) were evaluated individually and in combination. Overall, the sensitivities, specificities, positive predictive values, and negative predictive values calculated were poor and inconsistent, and they did not improve within subgroup analysis or when physical findings were combined. Further statistical analysis suggested the physical findings, whether in isolation or in combination, have poor discrimination between patients that have and do not have inhalation injury (AUC < 0.7, P > .05) and poor agreement with the diagnosis made by bronchoscopy (κ < 0.4, P > .05). This remained true in the subgroup analysis as well. Our data demonstrated the findings of SN, CS, and FB are unreliable evidence for inhalation injury, even in the context of an enclosed space mechanism of injury. Thus, these physical findings are not absolute indicators for intubation and should be interpreted as one component of the history and physical.

Low-latitude ice cores and freshwater availability

NASA Astrophysics Data System (ADS)

Kehrwald, Natalie Marie

2009-12-01

Recent retreat of Tibetan Plateau glaciers affects at least half a billion people. Himalayan glaciers seasonally release meltwater into tributaries of the Indus, Ganges, and Brahmaputra Rivers and supply freshwater necessary to support agricultural and economic practices. Tibetan Plateau glaciers are retreating more rapidly than mountain glaciers elsewhere in the world, and this retreat is accelerating. The Naimona'nyi (30°27'N; 81°91'E, 6050 m a.s.l), Guliya (35°17'N; 81°29'E, 6710 m a.s.l.) and Dasuopu (28°23'N; 85°43'E, 7200 m a.s.l.) ice cores place this recent retreat into a longer time perspective through quantifying climate parameters such as past temperature, aridity, and atmospheric chemistry. Naimona'nyi has not accumulated mass since at least 1950, as evidenced by the virtual lack of radiogenic isotopes (36Cl, 3 H, and beta radioactivity) present in the ice core. These isotopes were produced by U.S. and Soviet atmospheric thermonuclear bomb tests conducted in the 1950s and 1960s and provide independent dating horizons for the ice cores. Lead-210 dates imply that the uppermost preserved glacial ice on Naimona'nyi formed during the 1940s. While this is the highest documented glacial thinning in the world other glaciers at elevations similar to that of Naimona'nyi, such as Kilimanjaro (3°4'S; 37°21'E, 5893 m a.s.l.), are also losing mass at their summits. The global scope of high-elevation glacial thinning suggests that ablation on the Earth's highest ice fields may be more prevalent as global mean temperatures continue to increase. Glacial thinning has not been taken into account in future projections of regional freshwater availability, and the net mass loss indicates that Himalayan glaciers currently store less freshwater than assumed in models. The acceleration of Tibetan Plateau glacial retreat has been hypothesized to be due in part to deposition of black carbon (BC) from biomass burning on to ice fields, thereby lowering the reflectivity of the glacier surface and melting the upper ice. The application of a novel technique of measuring and radiocarbon-dating ultra-small samples (< 100mug) of the BC and total organic carbon (TOC) fractions of Naimona'nyi demonstrates a decrease (˜12 to 14 ka versus ˜7 ka) in the composite age of BC in the upper 40 m and lowest 20 m of the 137 m ice core, suggesting the incorporation of radiocarbon-dead BC. Precambrian black shale in the Lesser Himalaya provide a natural source material which may be operationally defined as black carbon and which may incorporate radiocarbon-dead sediments into the bulk 14C measurements, yet as the mean 14C age is ˜10 ka, modern BC from biomass burning must also be incorporated into the ice core record. While the uppermost sample (5 m) contains 38% BC, 210 Pb dates show that this depth corresponds to an age before 1850 AD, or before the regional Industrial Revolution. As BC is a hydrophobic substance, the BC is unlikely to have migrated through the firn and glacial ice. Therefore, the high-elevation thinning on Naimona'nyi appears to be a response to increased temperatures rather than primarily driven by changes in surface albedo. This technique was applied to the annually-dated ice core from the accumulating summit of the Quleccaya ice cap, Peru (13'56'S; 70°50'W; 5670 m a.s.l.). A marked increase in modern BC and TOC was measured since 1880 AD. No increase in radiocarbon-dead (> 60,000 ka) BC or TOC was noted, suggesting that the source of the carbon was from biomass burning, with a possible contribution of Amazon slash and burn clearing, rather than the input of fossil fuel combustion. The age of the BC and TOC is thousands of years older than the age of the surrounding ice, and should not be used to date the ice core. Although Naimona'nyi provides challenges for constructing an ice core chronology due to its lack of independent horizons such as volcanic activity, methane gas measurements, 14C dates, 3H, 36Cl, or beta radioactivity, the oxygen isotopic record can be correlated with the neighboring Dasuopu and Guliya ice cores. Naimona'nyi contains a pronounced positive ˜10‰ shift in delta18O in the basal 37 m of the core which mimics similar isotopic shifts in regional speleothems, lacustrian sediments, and planktonic foraminifera proxy records. This distinct shift is attributed to amplified monsoon intensity caused by increased summer insolation at 30°N. This correlation between regional proxy records results in a basal age of ˜8.6 ka for Naimona'nyi, suggesting that the ice field grew as a response to tropical rather than polar climate forcings.

The ignition of carbon detonations via converging shock waves in white dwarfs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Ken J.; Bildsten, Lars, E-mail: kenshen@astro.berkeley.edu, E-mail: bildsten@kitp.ucsb.edu

2014-04-10

The progenitor channel responsible for the majority of Type Ia supernovae is still uncertain. One emergent scenario involves the detonation of a He-rich layer surrounding a C/O white dwarf, which sends a shock wave into the core. The quasi-spherical shock wave converges and strengthens at an off-center location, forming a second, C-burning, detonation that disrupts the whole star. In this paper, we examine this second detonation of the double detonation scenario using a combination of analytic and numeric techniques. We perform a spatially resolved study of the imploding shock wave and outgoing detonation and calculate the critical imploding shock strengthsmore » needed to achieve a core C detonation. We find that He detonations in recent two-dimensional simulations yield converging shock waves that are strong enough to ignite C detonations in high-mass C/O cores, with the caveat that a truly robust answer requires multi-dimensional detonation initiation calculations. We also find that convergence-driven detonations in low-mass C/O cores and in O/Ne cores are harder to achieve and are perhaps unrealized in standard binary evolution.« less

Carbonaceous aerosol tracers in ice-cores record multi-decadal climate oscillations

PubMed Central

Seki, Osamu; Kawamura, Kimitaka; Bendle, James A. P.; Izawa, Yusuke; Suzuki, Ikuko; Shiraiwa, Takayuki; Fujii, Yoshiyuki

2015-01-01

Carbonaceous aerosols influence the climate via direct and indirect effects on radiative balance. However, the factors controlling the emissions, transport and role of carbonaceous aerosols in the climate system are highly uncertain. Here we investigate organic tracers in ice cores from Greenland and Kamchatka and find that, throughout the period covered by the records (1550 to 2000 CE), the concentrations and composition of biomass burning-, soil bacterial- and plant wax- tracers correspond to Arctic and regional temperatures as well as the warm season Arctic Oscillation (AO) over multi-decadal time-scales. Specifically, order of magnitude decreases (increases) in abundances of ice-core organic tracers, likely representing significant decreases (increases) in the atmospheric loading of carbonaceous aerosols, occur during colder (warmer) phases in the high latitudinal Northern Hemisphere. This raises questions about causality and possible carbonaceous aerosol feedback mechanisms. Our work opens new avenues for ice core research. Translating concentrations of organic tracers (μg/kg-ice or TOC) from ice-cores, into estimates of the atmospheric loading of carbonaceous aerosols (μg/m3) combined with new model constraints on the strength and sign of climate forcing by carbonaceous aerosols should be a priority for future research. PMID:26411576

Regulation of cellular marker modulated upon irradiation of low power laser light in burn injured mice

NASA Astrophysics Data System (ADS)

Rathnakar, Bharath; Prabhu, Vijendra; Rao, Bola Sadashiva Satish; Chandra, Subhash; Rai, Sharada; Mahato, Krishna Kishore

2016-12-01

The present study intends to understand the importance of cellular marker in tissue regeneration regulated upon irradiation of low power laser light in burn inflicted mice. Under anesthetic conditions, the thermal injury was induced on Swiss albino mice of either sex. Following injury, the animals were randomly divided into three groups; i. e., un-illuminated control, the group treated with 5% Povidone iodine (reference standard) and single exposure of 3 J/cm2 (830 nm). Burn tissue samples from each group were excised at day 6 post burn injury upon euthanization and used for histological and immunohistochemical analysis. Haematoxylin and Eosin (H and E) staining was performed on the selected sections to asses proliferation and angiogenesis at day 6 post-injury. For immunohistochemical analysis, tissue sections from all the three treatment groups on day 6 were stained using specific antibody against Proliferating cell nuclear antigen (PCNA). The results of the histological and immunohistochemical analysis showed improved tissue restoration in animals treated with optimal laser influence as compared to un-illuminated controls. The findings of present study clearly demonstrated the beneficial effects of 830 nm laser in burn wound healing and its influence in regulating the cellular marker.

Multiple burn fuel-optimal orbit transfers: Numerical trajectory computation and neighboring optimal feedback guidance

NASA Technical Reports Server (NTRS)

Chuang, C.-H.; Goodson, Troy D.; Ledsinger, Laura A.

1995-01-01

This report describes current work in the numerical computation of multiple burn, fuel-optimal orbit transfers and presents an analysis of the second variation for extremal multiple burn orbital transfers as well as a discussion of a guidance scheme which may be implemented for such transfers. The discussion of numerical computation focuses on the use of multivariate interpolation to aid the computation in the numerical optimization. The second variation analysis includes the development of the conditions for the examination of both fixed and free final time transfers. Evaluations for fixed final time are presented for extremal one, two, and three burn solutions of the first variation. The free final time problem is considered for an extremal two burn solution. In addition, corresponding changes of the second variation formulation over thrust arcs and coast arcs are included. The guidance scheme discussed is an implicit scheme which implements a neighboring optimal feedback guidance strategy to calculate both thrust direction and thrust on-off times.

Measurement of Solid Rocket Propellant Burning Rate Using X-ray Imaging

NASA Astrophysics Data System (ADS)

Denny, Matthew D.

The burning rate of solid propellants can be difficult to measure for unusual burning surface geometries, but X-ray imaging can be used to measure burning rate. The objectives of this work were to measure the baseline burning rate of an electrically-controlled solid propellant (ESP) formulation with real-time X-ray radiography and to determine the uncertainty of the measurements. Two edge detection algorithms were written to track the burning surface in X-ray videos. The edge detection algorithms were informed by intensity profiles of simulated 2-D X-ray images. With a 95% confidence level, the burning rates measured by the Projected-Slope Intersection algorithm in the two combustion experiments conducted were 0.0839 in/s +/-2.86% at an average pressure of 407 psi +/-3.6% and 0.0882 in/s +/-3.04% at 410 psi +/-3.9%. The uncertainty percentages were based on the statistics of a Monte Carlo analysis on burning rate.

Emissions of nitrogen-containing organic compounds from the burning of herbaceous and arboraceous biomass: Fuel composition dependence and the variability of commonly used nitrile tracers

NASA Astrophysics Data System (ADS)

Coggon, Matthew M.; Veres, Patrick R.; Yuan, Bin; Koss, Abigail; Warneke, Carsten; Gilman, Jessica B.; Lerner, Brian M.; Peischl, Jeff; Aikin, Kenneth C.; Stockwell, Chelsea E.; Hatch, Lindsay E.; Ryerson, Thomas B.; Roberts, James M.; Yokelson, Robert J.; Gouw, Joost A.

2016-09-01

Volatile organic compounds (VOCs) emitted from residential wood and crop residue burning were measured in Colorado, U.S. When compared to the emissions from crop burning, residential wood burning exhibited markedly lower concentrations of acetonitrile, a commonly used biomass burning tracer. For both herbaceous and arboraceous fuels, the emissions of nitrogen-containing VOCs (NVOCs) strongly depend on the fuel nitrogen content; therefore, low NVOC emissions from residential wood burning result from the combustion of low-nitrogen fuel. Consequently, the emissions of compounds hazardous to human health, such as HNCO and HCN, and the formation of secondary pollutants, such as ozone generated by NOx, are likely to depend on fuel nitrogen. These results also demonstrate that acetonitrile may not be a suitable tracer for domestic burning in urban areas. Wood burning emissions may be best identified through analysis of the emissions profile rather than reliance on a single tracer species.

A five year review of paediatric burns and social deprivation: Is there a link?

PubMed

Richards, Helen; Kokocinska, Maria; Lewis, Darren

2017-09-01

To establish if there is a correlation between burn incidence and social deprivation in order to formulate a more effective burns prevention strategy. A quantitative retrospective review of International Burn Injury Database (IBID) was carried out over a period from 2006 to 2011 to obtain data for children referred to our burns centre in West Midlands. Social deprivation scores for geographical areas were obtained from Office of National Statistics (ONS). Statistical analysis was carried out using Graphpad Prism. 1688 children were reviewed at our burns centre. Statistical analysis using Pearson correlation coefficient showed a slight association between social deprivation and increasing burn incidence r 2 =0.1268, 95% confidence interval 0.018-0.219, p value<0.0001. There was a slight male preponderance (58%). The most common mechanism of injury was scalding (61%). The most commonly affected age group were 1-2 year olds (38%). There were statistically significant differences in the ethnicity of children with significantly more children from Asian and African backgrounds being referred compared to Caucasian children. We found that appropriate first aid was administered in 67% of cases overall. We did not find a statistically significant link between first aid provision and social deprivation score. There was only a slight positive correlation between social deprivation and burn incidence. However, there did not seem to be any change in mechanism of burn in the most deprived groups compared to overall pattern, nor was there a significant difference in appropriate first aid provision. It would seem that dissemination of burn prevention strategies and first aid advice need to be improved across all geographical areas as this was uniformly lacking and the increased burn incidence in more socially deprived groups, although present, was not statistically significant. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

[Risk factors for development of hypomagnesemia in the burned patient].

PubMed

Durán-Vega, Héctor César; Romero-Aviña, Francisco Javier; Gutiérrez-Salgado, Jorge Eduardo; Silva-Díaz, Teresita; Ramos-Durón, Luis Ernesto; Carrera-Gómez, Francisco Javier

2004-01-01

Electrolyte abnormalities are common in the severely burned patient. There is little information with regard to the frequency and magnitude of hypomagnesemia, as well as on risk factors for this condition. We performed an observational, retrospective analysis of 35 burned patients treated at the Plastic and Reconstructive Surgery Service at the Hospital Central Sur PEMEX, Mexico City. We determined serum magnesium behavior and divided patients into two groups: the first included 11 patients with burns and hypomagnesemia, and the second, 24 patients with burns but without hypomagnesemia. Risk factor identification was performed. We found patient at risk was the one with more than 40% of 2nd or 3rd degree total burned body area, in day 4 or 10 after the burn, and with hypokalemia, hypocalcemia, or both, and without intravenous (i.v.) supplementation of magnesium. The best way to prevent or avoid major complications is to identify the high-risk patient, or to diagnose earlier.

Improving the accuracy of burn-surface estimation.

PubMed

Nichter, L S; Williams, J; Bryant, C A; Edlich, R F

1985-09-01

A user-friendly computer-assisted method of calculating total body surface area burned (TBSAB) has been developed. This method is more accurate, faster, and subject to less error than conventional methods. For comparison, the ability of 30 physicians to estimate TBSAB was tested. Parameters studied included the effect of prior burn care experience, the influence of burn size, the ability to accurately sketch the size of burns on standard burn charts, and the ability to estimate percent TBSAB from the sketches. Despite the ability for physicians of all levels of training to accurately sketch TBSAB, significant burn size over-estimation (p less than 0.01) and large interrater variability of potential consequence was noted. Direct benefits of a computerized system are many. These include the need for minimal user experience and the ability for wound-trend analysis, permanent record storage, calculation of fluid and caloric requirements, hemodynamic parameters, and the ability to compare meaningfully the different treatment protocols.

Erosive burning research. [for solid-propellant rocket engines

NASA Technical Reports Server (NTRS)

Strand, L.; Yang, L. C.; Nguyen, M. H.; Cohen, N. S.

1986-01-01

A status report is given on the results for the completed tests in a series of motor firings being carried out to measure the effects of the parameters that are considered to most strongly influence the scaling to larger rocket motor sizes of the transition to/or threshold conditions for erosive burning rate augmentation. Propellant burning rates at locations along the axis of the test motors are measured with a newly developed plasma capacitance gauge technique. The measured results are compared with erosive-burning predictions from a supporting ballistics analysis. The completed motor firings have successfully demonstrated response to the designed test variables. The trends with varying propellant burning rate, chamber pressure, and mass flow rate are consistent with existing results, but no pronounced effect of surface roughness has been observed. Rather, the influence of propellant oxidizer particle size on erosive burning is through its effect on the base, no-corssflow burning rate.

Clothing burns in Canadian children

PubMed Central

Stanwick, Richard S.

1985-01-01

A Canadian survey of 11 tertiary care pediatric centres with specialized burn facilities revealed that an estimated 37 children up to 9 years of age are admitted annually to such hospitals because of clothing burns. Sleepwear accounts for an estimated 21 such burns per year. Girls were found to suffer the most severe burns and represented eight of the nine children in the series who died. Loose and flowing garments dominated the girls' styles. The results of multiple-regression analysis confirmed that style of clothing (loose and flowing as opposed to snug) was the most significant predictor of burn severity, length of hospital stay, the need for skin grafting and survival. The ignition situation (avoidance of parental supervision at the time of injury) was the only other important predictor. The success of regulatory actions in other countries in reducing the incidence of severe clothing burns is reviewed, and preventive strategies for Canada are explored. ImagesFig. 2 PMID:3995433

Overview of the South American biomass burning analysis (SAMBBA) field experiment

NASA Astrophysics Data System (ADS)

Morgan, W. T.; Allan, J. D.; Flynn, M.; Darbyshire, E.; Hodgson, A.; Johnson, B. T.; Haywood, J. M.; Freitas, S.; Longo, K.; Artaxo, P.; Coe, H.

2013-05-01

Biomass burning represents one of the largest sources of particulate matter to the atmosphere, which results in a significant perturbation to the Earth's radiative balance coupled with serious negative impacts on public health. Globally, biomass burning aerosols are thought to exert a small warming effect of 0.03 Wm-2, however the uncertainty is 4 times greater than the central estimate. On regional scales, the impact is substantially greater, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months (usually from August-October). Furthermore, a growing number of people live within the Amazon region, which means that they are subject to the deleterious effects on their health from exposure to substantial volumes of polluted air. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil, are presented here. A suite of instrumentation was flown on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft and was supported by ground based measurements, with extensive measurements made in Porto Velho, Rondonia. The aircraft sampled a range of conditions with sampling of fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate.

Pattern of burn injury at north of Jordan

PubMed Central

Bataineh, Ziad A; Al Quran, Thekraiat M; Al Balas, Hamzeh; Khammash, Muhmammad R

2018-01-01

To the best of our knowledge, pattern of burn injury was not reported yet at our region, our hospital considered the only tertiary referral center with the only burn unit at the region since 2001 till date, a retrospective analysis of our computerized filing system recorded 527 burn patients between 2001-2016, mean age was 26 years; 1.27:1 was the male to female ratio, 79 patients were found to have major burns, 46% of admissions were below 20 years’ age, 92% was at domestic site of affection and 65% due to flame burn followed by scald burn in about 23%. The limbs were the most affected body site, majority of patients were below 15% TBSA and partial thickness, 77 patients found to have inhalational injury. Our mean hospital stay was 16 days and mortality was 8.2%. Mortality was associated with high TBSA affection, depth and flame type. This study shows the pattern of burn at north of Jordan, preventive measures by education and observation will reduce the incidence of burn and its sequel, non-flammable cook plates and stoves will probably help in decrease burn morbidity and mortality. PMID:29531853

Perceived social support among patients with burn injuries: A perspective from the developing world.

PubMed

Waqas, Ahmed; Turk, Marvee; Naveed, Sadiq; Amin, Atif; Kiwanuka, Harriet; Shafique, Neha; Chaudhry, Muhammad Ashraf

2018-02-01

Social support is among the most well-established predictors of post-burn psychopathology after burn. Despite a disproportionately large burden of burns in the developing world, the nature of social support among burn patients in this context remains elusive. We, therefore, seek to investigate social support and its biopsychosocial determinants among patients with burn injuries in Pakistan. A cross-sectional study of 343 patients presenting with burn injuries at four teaching hospitals in the Punjab province of Pakistan was conducted. Patient evaluation consisted of a multi-part survey of demographic status, clinical features, and social support as measured by the validated Urdu translation of the Multidimensional Scale of Perceived Social Support (MSPSS). Multiple regression analysis was performed to evaluate associations between patient characteristics and MSPSS score. Mean overall MSPSS score was 57.64 (std dev 13.57). Notable positive predictors of social support include male gender, Punjabi ethnicity, burn surface area, and ego resiliency. Our study reveals a troubling pattern of inadequate social support among certain subgroups of Pakistani burn patients. Addressing these inequities in the provision of social support must be prioritized as part of the global burn care agenda. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

The Associations of Gender With Social Participation of Burn Survivors: A Life Impact Burn Recovery Evaluation Profile Study.

PubMed

Levi, Benjamin; Kraft, Casey T; Shapiro, Gabriel D; Trinh, Nhi-Ha T; Dore, Emily C; Jeng, James; Lee, Austin F; Acton, Amy; Marino, Molly; Jette, Alan; Armstrong, Elizabeth A; Schneider, Jeffrey C; Kazis, Lewis E; Ryan, Colleen M

2018-05-04

Burn injury can be debilitating and affect survivors' quality of life in a profound fashion. Burn injury may also lead to serious psychosocial challenges that have not been adequately studied and addressed. Specifically, there has been limited research into the associations of burn injury on community reintegration based on gender. This work analyzed data from 601 burn survivors who completed field testing of a new measure of social participation for burn survivors, the Life Impact Burn Recovery Evaluation (LIBRE) Profile. Differences in item responses between men and women were examined. Scores on the six LIBRE Profile scales were then compared between men and women using analysis of variance and adjusted linear multivariate regression modeling. Overall, men scored significantly better than women on four of the six LIBRE Profile scales: Sexual Relationships, Social Interactions, Work & Employment, and Romantic Relationships. Differences were not substantially reduced after adjustment for demographic characteristics and burn size. Men scored better than women in most of the areas measured by the LIBRE Profile. These gender differences are potentially important for managing burn patients during the post-injury recovery period.

Spectrometer Sensitivity Investigations on the Spectrometric Oil Analysis Program.

DTIC Science & Technology

1983-04-22

31 H. ACID DISSOLUTION METHOD (ADM) ........... 90 31 I. ANALYSIS OF SAMPLES............................ 31 jJ. PARTICLE TRANSPORT EFFICIENCY OF...THE ROTATING *DISK.................................... 32 I .K. A/E35U-3 ACID DISSOLUTION METHOD.................. 32 L. BURN TIME... ACID DISSOLUTION METHOD ......... ,...,....... 95 3. EFFECT OF BURN TIME ............ 95 4. DIRECT SAMPLE INTRODUCTION .......................... 95

Clinical and demographic features of pediatric burns in the eastern provinces of Turkey

PubMed Central

2011-01-01

Background The aim of this study is to perform a retrospective analysis of the causes of burns observed in children in the eastern provinces of Turkey. Method In this study, patients were studied retrospectively with regard to their age, sex, cause of burns, seasonal variations, social and economic factors, length of hospital stay, burned body surface area, medical history, site of injury, and mortality. Results A total of 125 patients undergoing inpatient treatment were male, (53.2%) and 110 were female (46.8%). The most common causes of burns in patients treated on an inpatient basis were scald burns (65.5%) and tandir burns (15.7%). The mean total body surface area of all the patients was 12.17+9.86%. When the patients were grouped according to tandir, cauldron, and others burn causes, a significant difference was seen between the in burn percentages caused by tandir and cauldron burns and other causes (p < 0.001). Higher burn percentages were seen for cauldron burns than for tandir burns (p < 0.05). The average length of hospital stay was 17.67+13.64 days. When the patients were grouped according to burn causes (tandir, cauldron, and others), a significant difference was determined between the hospitalization periods of patients with tandir burns and other burn causes (p = 0.001) The most commonly proliferating microorganism in burned areas was Pseudomonas aeruginosa (20.4%). Of the 235 patients, 61 were treated in operating rooms. During the 24-month period of the study, 2 of the 235 patients died (0.85%). Conclusion Pediatric burns in the eastern part of Turkey are different from those in other parts of Turkey, as well as in other countries. Due to the lifestyle of the region, tandir and cauldron burns, which cause extensive burn areas and high morbidity, are frequently seen in children. Therefore, precautions and educational programs related to the use of tandirs and cauldrons are needed in this region. PMID:21244683

40 CFR 63.7550 - What reports must I submit and when?

Code of Federal Regulations, 2012 CFR

2012-07-01

... applicable. (6) A signed statement indicating that you burned no new types of fuel. Or, if you did burn a new type of fuel, you must submit the calculation of chlorine input, using Equation 5 of § 63.7530, that... demonstrate compliance through fuel analysis). If you burned a new type of fuel, you must submit the...

More About Professionalism: A Second Look at Burns and Haga. Faculty Research Working Paper Series, 79-5.

ERIC Educational Resources Information Center

Sheldahl, Terry K.

Burns and Haga's critique of the "shopping list" characterization of professions (1977) is examined, and an alternative analysis is proposed and applied to management accounting. According to Burns and Haga, a field is regarded as a profession if it serves needs recognizable within the society as crucial and is imbued with substantial…

UF6 breeder reactor power plants for electric power generation

NASA Technical Reports Server (NTRS)

Rust, J. H.; Clement, J. D.; Hohl, F.

1976-01-01

The reactor concept analyzed is a U-233F6 core surrounded by a molten salt (Li(7)F, BeF2, ThF4) blanket. Nuclear survey calculations were carried out for both spherical and cylindrical geometries. Thermodynamic cycle calculations were performed for a variety of Rankine cycles. A conceptual design is presented along with a system layout for a 1000 MW stationary power plant. Advantages of the gas core breeder reactor (GCBR) are as follows: (1) high efficiency; (2) simplified on-line reprocessing; (3) inherent safety considerations; (4) high breeding ratio; (5) possibility of burning all or most of the long-lived nuclear waste actinides; and (6) possibility of extrapolating the technology to higher temperatures and MHD direct conversion.

Progenitors of Core-Collapse Supernovae

NASA Astrophysics Data System (ADS)

Hirschi, R.; Arnett, D.; Cristini, A.; Georgy, C.; Meakin, C.; Walkington, I.

2017-02-01

Massive stars have a strong impact on their surroundings, in particular when they produce a core-collapse supernova at the end of their evolution. In these proceedings, we review the general evolution of massive stars and their properties at collapse as well as the transition between massive and intermediate-mass stars. We also summarise the effects of metallicity and rotation. We then discuss some of the major uncertainties in the modelling of massive stars, with a particular emphasis on the treatment of convection in 1D stellar evolution codes. Finally, we present new 3D hydrodynamic simulations of convection in carbon burning and list key points to take from 3D hydrodynamic studies for the development of new prescriptions for convective boundary mixing in 1D stellar evolution codes.

Shift Verification and Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandya, Tara M.; Evans, Thomas M.; Davidson, Gregory G

2016-09-07

This documentation outlines the verification and validation of Shift for the Consortium for Advanced Simulation of Light Water Reactors (CASL). Five main types of problems were used for validation: small criticality benchmark problems; full-core reactor benchmarks for light water reactors; fixed-source coupled neutron-photon dosimetry benchmarks; depletion/burnup benchmarks; and full-core reactor performance benchmarks. We compared Shift results to measured data and other simulated Monte Carlo radiation transport code results, and found very good agreement in a variety of comparison measures. These include prediction of critical eigenvalue, radial and axial pin power distributions, rod worth, leakage spectra, and nuclide inventories over amore » burn cycle. Based on this validation of Shift, we are confident in Shift to provide reference results for CASL benchmarking.« less

Climatology of Aerosol Optical Properties in Southern Africa

NASA Technical Reports Server (NTRS)

Queface, Antonio J.; Piketh, Stuart J.; Eck, Thomas F.; Tsay, Si-Chee

2011-01-01

A thorough regionally dependent understanding of optical properties of aerosols and their spatial and temporal distribution is required before we can accurately evaluate aerosol effects in the climate system. Long term measurements of aerosol optical depth, Angstrom exponent and retrieved single scattering albedo and size distribution, were analyzed and compiled into an aerosol optical properties climatology for southern Africa. Monitoring of aerosol parameters have been made by the AERONET program since the middle of the last decade in southern Africa. This valuable information provided an opportunity for understanding how aerosols of different types influence the regional radiation budget. Two long term sites, Mongu in Zambia and Skukuza in South Africa formed the core sources of data in this study. Results show that seasonal variation of aerosol optical thicknesses at 500 nm in southern Africa are characterized by low seasonal multi-month mean values (0.11 to 0.17) from December to May, medium values (0.20 to 0.27) between June and August, and high to very high values (0.30 to 0.46) during September to November. The spatial distribution of aerosol loadings shows that the north has high magnitudes than the south in the biomass burning season and the opposite in none biomass burning season. From the present aerosol data, no long term discernable trends are observable in aerosol concentrations in this region. This study also reveals that biomass burning aerosols contribute the bulk of the aerosol loading in August-October. Therefore if biomass burning could be controlled, southern Africa will experience a significant reduction in total atmospheric aerosol loading. In addition to that, aerosol volume size distribution is characterized by low concentrations in the non biomass burning period and well balanced particle size contributions of both coarse and fine modes. In contrast high concentrations are characteristic of biomass burning period, combined with significant dominance of fine mode particles.

Civilian blast-related burn injuries

PubMed Central

Patel, J.N.; Tan, A.; Dziewulski, P.

2016-01-01

Summary There is limited English literature describing the experience of a civilian hospital managing blast-related burn injuries. As the largest regional burn unit, we reviewed our cases with the aim of identifying means to improve current management. A 6-year retrospective analysis of all patients coded as sustaining blast-related burns was conducted through the unit’s burns database. Medical case notes were reviewed for information on burn demographics, management and outcomes. 42 patients were identified. Male to female ratio was 37:5. Age range was 12-84 years, (mean=33 years). Total body surface area (%TBSA) burn ranged from 0.25% to 60%, (median=1%). The most common burn injury was flame (31/42, 73.8%). Gas explosions were the most common mechanism of injury (19 cases; 45.2%). 7/42 cases (16.7%) had full ATLS management pre-transfer to the burns unit. The Injury Severity Score (ISS) ranged from 0-43 (median=2). 17/42 (40.4%) patients required admission. 37/36 (88.1%) patients were managed conservatively of which 1 patient later required surgery due to deeper burns. 5/42 (11.9%) patients required surgical management at presentation and these were noted to be burns with >15% TBSA requiring resuscitation. One case required emergency escharotomies and finger amputations. All patients survived their burn injuries. Blast-related burn injuries are generally uncommon in the civilian setting. Following proper assessment, most of these cases can be deemed as minor injuries and managed conservatively. Improvement in burns management education and training at local emergency departments would provide efficient patient care and avoid unnecessary referrals to a burns unit. PMID:27857651

Patient experiences of burn scars in adults and children and development of a health-related quality of life conceptual model: A qualitative study.

PubMed

Simons, Megan; Price, Nathaniel; Kimble, Roy; Tyack, Zephanie

2016-05-01

The aim of this study was to understand the impact of burn scars on health-related quality of life (HRQOL) from the perspective of adults and children with burn scars, and caregivers to inform the development of a conceptual model of burn scar HRQOL. Twenty-one participants (adults and children) with burn scars and nine caregivers participated in semi-structured, face-to-face interviews between 2012 and 2013. During the interviews, participants were asked to describe features about their (or their child's) burn scars and its impact on everyday life. Two coders conducted thematic analysis, with consensus achieved through discussion and review with a third coder. The literature on HRQOL models was then reviewed to further inform the development of a conceptual model of burn scar HRQOL. Five themes emerged from the qualitative data: 'physical and sensory symptoms', 'impact of burn scar interventions', 'impact of burn scar symptoms', 'personal factors' and 'change over time'. Caregivers offered further insights into family functioning after burn, and the impacts of burn scars and burn scar interventions on family life. In the conceptual model, symptoms (sensory and physical) of burn scars are considered proximal to HRQOL, with distal indicators including functioning (physical, emotional, social, cognitive), individual factors and the environment. Overall quality of life was affected by HRQOL. Understanding the impact of burn scars on HRQOL and the development of a conceptual model will inform future burn scar research and clinical practice. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Impacts of Colonial Deforestation on Sediment Organic Carbon Fluxes and Budget Using Black Carbon Chronology: Waiapu Continental Shelf, New Zealand

NASA Astrophysics Data System (ADS)

Wadman, H. M.; Canuel, E. A.; Bauer, J. E.; McNinch, J. E.

2009-12-01

Small, mountainous rivers deliver a disproportionate amount of sediment and associated organic matter to coastal regions globally. The Waiapu River, North Island, New Zealand, is characterized by one of the highest sediment yields on earth, providing a model system for studying episodic delivery and preservation of sedimentary organic matter in an energetic, aggradational setting. Hyperpycnal plumes provide the primary mode of sediment delivery, depositing fine-grained sediment as flood layers on the inner shelf. Severe erosion following colonial-era (~1890-1920) slash and burn deforestation increased the sediment yield to the shelf 4- to 5-fold relative to previous levels. Colonial catchment-wide burning also produced black carbon (BC), which may be used to establish chronological control in the heterogeneous inner shelf sediments that are not easily dateable using traditional techniques. While recent work indicates that these inner shelf flood layers sequester ~16-34% of the total fine-grained sediment budget, comparable to the amount preserved on the mid-outer shelf, little is understood about the organic matter associated with these inner shelf sediments. High-resolution seismic reflection data were used to select four representative cores to characterize total sedimentary BC, total organic carbon (TOC) and total nitrogen (TN) sequestered in the inner shelf fine-grained sediments. Soot and graphitic BC (SGBC) was quantified using chemo-thermal oxidation (CTO-375), while coarse-grained BC (CGBC) was quantified using traditional point-counting methodologies. SGBC weight percentages ranged from ~0.01-0.07, and peaked at ~150cm depth in all four cores. This interval corresponds to peak abundance of CGBC as well. The ~150cm interval is interpreted to represent the height of colonial slash and burn deforestation, and is further supported by fining-upward sequences in all of the cores as well as by multiple 14C dates. Overall, SGBC represented an average of 29% (range 7-75%) of the TOC throughout the cores, with the highest levels found in the deforestation layer at ~150cm (average 44%, range 30-75%). A secondary increase in % SGBC was found in the upper 50cm of the cores and is interpreted as increasing global BC production by diesel combustion in the 1970s. TOC and TN weight percentages associated with the fine-sediment fraction did not differ markedly above and below the deforestation layer. TOC and TN associated with the bulk sediment, however, did show increases in weight percent above ~150cm. This suggests that either 1) increases in fine-grained sedimentary organic material associated with the recent increase in sediment yield have been effectively remineralized, or 2) sedimentary organic matter is bimodal in origin (recent plant material vs. ancient, bedrock-derived carbon), and size-related variations in catchment and burial dynamics are influencing the fate of the different size fractions of organic material.

A Large Stellar Evolution Database for Population Synthesis Studies. I. Scaled Solar Models and Isochrones

NASA Astrophysics Data System (ADS)

Pietrinferni, Adriano; Cassisi, Santi; Salaris, Maurizio; Castelli, Fiorella

2004-09-01

We present a large and updated stellar evolution database for low-, intermediate-, and high-mass stars in a wide metallicity range, suitable for studying Galactic and extragalactic simple and composite stellar populations using population synthesis techniques. The stellar mass range is between ~0.5 and 10 Msolar with a fine mass spacing. The metallicity [Fe/H] comprises 10 values ranging from -2.27 to 0.40, with a scaled solar metal distribution. The initial He mass fraction ranges from Y=0.245, for the more metal-poor composition, up to 0.303 for the more metal-rich one, with ΔY/ΔZ~1.4. For each adopted chemical composition, the evolutionary models have been computed without (canonical models) and with overshooting from the Schwarzschild boundary of the convective cores during the central H-burning phase. Semiconvection is included in the treatment of core convection during the He-burning phase. The whole set of evolutionary models can be used to compute isochrones in a wide age range, from ~30 Myr to ~15 Gyr. Both evolutionary models and isochrones are available in several observational planes, employing an updated set of bolometric corrections and color-Teff relations computed for this project. The number of points along the models and the resulting isochrones is selected in such a way that interpolation for intermediate metallicities not contained in the grid is straightforward; a simple quadratic interpolation produces results of sufficient accuracy for population synthesis applications.We compare our isochrones with results from a series of widely used stellar evolution databases and perform some empirical tests for the reliability of our models. Since this work is devoted to scaled solar chemical compositions, we focus our attention on the Galactic disk stellar populations, employing multicolor photometry of unevolved field main-sequence stars with precise Hipparcos parallaxes, well-studied open clusters, and one eclipsing binary system with precise measurements of masses, radii, and [Fe/H] of both components. We find that the predicted metallicity dependence of the location of the lower, unevolved main sequence in the color magnitude diagram (CMD) appears in satisfactory agreement with empirical data. When comparing our models with CMDs of selected, well-studied, open clusters, once again we were able to properly match the whole observed evolutionary sequences by assuming cluster distance and reddening estimates in satisfactory agreement with empirical evaluations of these quantities. In general, models including overshooting during the H-burning phase provide a better match to the observations, at least for ages below ~4 Gyr. At [Fe/H] around solar and higher ages (i.e., smaller convective cores) before the onset of radiative cores, the selected efficiency of core overshooting may be too high in our model, as well as in various other models in the literature. Since we also provide canonical models, the reader is strongly encouraged to always compare the results from both sets in this critical age range.

Standardization of deep partial-thickness scald burns in C57BL/6 mice

PubMed Central

Medina, Jorge L; Fourcaudot, Andrea B; Sebastian, Eliza A; Shankar, Ravi; Brown, Ammon W; Leung, Kai P

2018-01-01

Mouse burn models are used to understand the wound healing process and having a reproducible model is important. The different protocols used by researchers can lead to differences in depth of partial-thickness burn wounds. Additionally, standardizing a protocol for mouse burns in the laboratory for one strain may result in substantially different results in other strains. In our current study we describe the model development of a deep partial-thickness burn in C57BL/6 mice using hot water scalding as the source of thermal injury. As part of our model development we designed a template with specifications to allow for even contact of bare mouse skin (2×3 cm) with hot water while protecting the rest of the mouse. Burn depth was evaluated with H&E, Masson’s trichrome, and TUNEL staining. Final results were validated with pathology analysis. A water temperature of 54°C with a scalding time of 20 seconds produced consistent deep partial-thickness burns with available equipment described. Other than temperature and time, factors such as template materials and cooling steps after the burn could affect the uniformity of the burns. These findings are useful to burn research by providing some key parameters essential for researchers to simplify the development of their own mouse burn models. PMID:29755839

Effects of normal acceleration on transient burning rate augmentation of an aluminized solid propellant

NASA Technical Reports Server (NTRS)

Northam, G. B.

1972-01-01

Instantaneous burning rate data for a polybutadiene acrylic acid propellant, containing 16 weight percent aluminum, were calculated from the pressure histories of a test motor with 96.77 sq cm of burning area and a 5.08-cm-thick propellant web. Additional acceleration tests were conducted with reduced propellant web thicknesses of 3.81, 2.54, and 1.27 cm. The metallic residue collected from the various web thickness tests was characterized by weight and shape and correlated with the instantaneous burning rate measurements. Rapid depressurization extinction tests were conducted in order that surface pitting characteristics due to localized increased burning rate could be correlated with the residue analysis and the instantaneous burning rate data. The acceleration-induced burning rate augmentation was strongly dependent on propellant distance burned, or burning time, and thus was transient in nature. The results from the extinction tests and the residue analyses indicate that the transient rate augmentation was highly dependent on local enhancement of the combustion zone heat feedback to the surface by the growth of molten residue particles on or just above the burning surface. The size, shape, and number density of molten residue particles, rather than the total residue weight, determined the acceleration-induced burning rate augmentation.

Radioactivity from Fukushima Dai-ichi in air over Europe; part 2: what can it tell us about the accident?

PubMed

Kirchner, G; Bossew, P; De Cort, M

2012-12-01

It is shown which information can be extracted from the monitoring of radionuclides emitted from the Fukushima Dai-ichi nuclear power plant and transported to Europe. In this part the focus will be on the analysis of the concentration ratios. While (131)I, (134)Cs and (137)Cs were reported by most stations, other detected radionuclides, reported by some, are (95)Nb, (129m)Te, (132)Te, (132)I, (136)Cs and (140)La. From their activity ratios a mean burn-up of 26.7 GWd/t of the fuel from which they originated is estimated. Based on these data, inventories of radionuclides present at the time of the accident are calculated. The caesium activity ratios indicate emissions from the core of unit 4 which had been unloaded into the fuel storage pool prior to the accident. Copyright © 2011 Elsevier Ltd. All rights reserved.

Simulations of Atmospheric Plasma Arcs

NASA Astrophysics Data System (ADS)

Pearcy, Jacob; Chopra, Nirbhav; Jaworski, Michael

2017-10-01

We present the results of computer simulation of cylindrical plasma arcs with characteristics similar to those predicted to be relevant in magnetohydrodynamic (MHD) power conversion systems. These arcs, with core temperatures on the order of 1 eV, place stringent limitations on the lifetime of conventional electrodes used in such systems, suggesting that a detailed analysis of arc characteristics will be crucial in designing more robust electrode systems. Simulations utilize results from NASA's Chemical Equilibrium with Applications (CEA) program to solve the Elenbaas-Heller equation in a variety of plasma compositions, including approximations of coal-burning plasmas as well as pure gas discharges. The effect of carbon dioxide injection on arc characteristics, emulating discharges from molten carbonate salt electrodes, is also analyzed. Results include radial temperature profiles, composition maps, and current-voltage (IV) characteristics of these arcs. Work supported by DOE contract DE-AC02-09CH11466.

Mesa Isochrones and Stellar Tracks (MIST). I. Solar-scaled Models

NASA Astrophysics Data System (ADS)

Choi, Jieun; Dotter, Aaron; Conroy, Charlie; Cantiello, Matteo; Paxton, Bill; Johnson, Benjamin D.

2016-06-01

This is the first of a series of papers presenting the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks (MIST) project, a new comprehensive set of stellar evolutionary tracks and isochrones computed using MESA, a state-of-the-art open-source 1D stellar evolution package. In this work, we present models with solar-scaled abundance ratios covering a wide range of ages (5≤slant {log}({Age}) [{year}]≤slant 10.3), masses (0.1≤slant M/{M}⊙ ≤slant 300), and metallicities (-2.0≤slant [{{Z}}/{{H}}]≤slant 0.5). The models are self-consistently and continuously evolved from the pre-main sequence (PMS) to the end of hydrogen burning, the white dwarf cooling sequence, or the end of carbon burning, depending on the initial mass. We also provide a grid of models evolved from the PMS to the end of core helium burning for -4.0≤slant [{{Z}}/{{H}}]\\lt -2.0. We showcase extensive comparisons with observational constraints as well as with some of the most widely used existing models in the literature. The evolutionary tracks and isochrones can be downloaded from the project website at http://waps.cfa.harvard.edu/MIST/.

Atmospheric Effects of Biomass Burning

NASA Technical Reports Server (NTRS)

Thompson, Anne M.

2000-01-01

Biomass fires are both natural and anthropogenic in origin. The natural trigger is lightning, which leads to mid- and high-latitude fires and episodes of smoke and pollution associated with them. Lightning is also prominent in tropical regions when the dry season gives way to the wet season and lightning in convective systems ignites dry vegetation. Atmospheric consequences of biomass fires are complex. When considering the impacts of fires for a given ecosystem, inputs of fires must be compared to other process that emit trace gases and particles into the atmosphere. Other processes include industrial activity, fires for household purposes and biogenic sources which may themselves interact with fires. That is, fires may promote or restrict biogenic processes. Several books have presented various aspects of fire interactions with atmospheric chemistry and a cross-disciplinary review of a 1992 fire-oriented experiment appears in SAFARI: The Role of southern African Fires in Atmospheric and Ecological Environments. The IGAC/BIBEX core activity (see acronyms at end of Chapter) has sponsored field campaigns that integrate multiple aspects of fires ground-based measurements with an ecological perspective, atmospheric measurements with chemical and meteorological components, and remote sensing. This Chapter presents two aspects of biomass fires and the environment. Namely, the relationship between biomass burning and ozone is described, starting with a brief description of the chemical reactions involved and illustrative measurements and interpretation. Second, because of the need to observe biomass burning and its consequences globally, a summary of remote sensing approaches to the study of fires and trace gases is given. Examples in this Chapter are restricted to tropical burning for matters of brevity and because most burning activity globally is within this zone.

Statistical errors and systematic biases in the calibration of the convective core overshooting with eclipsing binaries. A case study: TZ Fornacis

NASA Astrophysics Data System (ADS)

Valle, G.; Dell'Omodarme, M.; Prada Moroni, P. G.; Degl'Innocenti, S.

2017-04-01

Context. Recently published work has made high-precision fundamental parameters available for the binary system TZ Fornacis, making it an ideal target for the calibration of stellar models. Aims: Relying on these observations, we attempt to constrain the initial helium abundance, the age and the efficiency of the convective core overshooting. Our main aim is in pointing out the biases in the results due to not accounting for some sources of uncertainty. Methods: We adopt the SCEPtER pipeline, a maximum likelihood technique based on fine grids of stellar models computed for various values of metallicity, initial helium abundance and overshooting efficiency by means of two independent stellar evolutionary codes, namely FRANEC and MESA. Results: Beside the degeneracy between the estimated age and overshooting efficiency, we found the existence of multiple independent groups of solutions. The best one suggests a system of age 1.10 ± 0.07 Gyr composed of a primary star in the central helium burning stage and a secondary in the sub-giant branch (SGB). The resulting initial helium abundance is consistent with a helium-to-metal enrichment ratio of ΔY/ ΔZ = 1; the core overshooting parameter is β = 0.15 ± 0.01 for FRANEC and fov = 0.013 ± 0.001 for MESA. The second class of solutions, characterised by a worse goodness-of-fit, still suggest a primary star in the central helium-burning stage but a secondary in the overall contraction phase, at the end of the main sequence (MS). In this case, the FRANEC grid provides an age of Gyr and a core overshooting parameter , while the MESA grid gives 1.23 ± 0.03 Gyr and fov = 0.025 ± 0.003. We analyse the impact on the results of a larger, but typical, mass uncertainty and of neglecting the uncertainty in the initial helium content of the system. We show that very precise mass determinations with uncertainty of a few thousandths of solar mass are required to obtain reliable determinations of stellar parameters, as mass errors larger than approximately 1% lead to estimates that are not only less precise but also biased. Moreover, we show that a fit obtained with a grid of models computed at a fixed ΔY/ ΔZ - thus neglecting the current uncertainty in the initial helium content of the system - can provide severely biased age and overshooting estimates. The possibility of independent overshooting efficiencies for the two stars of the system is also explored. Conclusions: The present analysis confirms that to constrain the core overshooting parameter by means of binary systems is a very difficult task that requires an observational precision still rarely achieved and a robust statistical treatment of the error sources.

Efficacy of enzymatic debridement of deeply burned hands.

PubMed

Krieger, Yuval; Bogdanov-Berezovsky, Alexander; Gurfinkel, Reuven; Silberstein, Eldad; Sagi, Amiram; Rosenberg, Lior

2012-02-01

The burned hand is a common and difficult to care-for entity in the field of burns. Due to the anatomy of the hand (important and delicate structures crowded in a small limited space without sub-dermal soft tissue), surgical debridement of the burned tissue is technically difficult and may cause considerable complications and, therefore, should be performed judiciously. Selective enzymatic debridement of the burn wound can preserve the spontaneous epithelialisation potential and reduce the added injury to the traumatised tissue added by a surgical debridement. The aim of the study was to assess the implication of a selective enzymatic compound (Debrase(®) - Ds) in the special field of deep hand burns, by comparing the actual burn area that required surgical coverage after enzymatic debridement to the burn area clinically judged to require skin grafting prior to debridement. This was a retrospective data collection and analysis from 154 complete files of prospective, open-label study in 275 hospitalised, Ds-treated burn patients. A total of 69 hand burns diagnosed as 'deep' was analysed; 36% of the wounds required surgical intervention after enzymatic debridement; 28.6% of the total burned area estimated initially as deep was covered by skin graft (statistically significant p<0.001). Debridement of deep-hand burns with a selective enzymatic agent decreased the perceived full-thickness wound area and skin-graft use. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

Utility of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) to non-invasively diagnose burn depth in a porcine model☆

PubMed Central

Burmeister, David M.; Ponticorvo, Adrien; Yang, Bruce; Becerra, Sandra C.; Choi, Bernard; Durkin, Anthony J.; Christy, Robert J.

2015-01-01

Surgical intervention of second degree burns is often delayed because of the difficulty in visual diagnosis, which increases the risk of scarring and infection. Non-invasive metrics have shown promise in accurately assessing burn depth. Here, we examine the use of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) for predicting burn depth. Contact burn wounds of increasing severity were created on the dorsum of a Yorkshire pig, and wounds were imaged with SFDI/LSI starting immediately after-burn and then daily for the next 4 days. In addition, on each day the burn wounds were biopsied for histological analysis of burn depth, defined by collagen coagulation, apoptosis, and adnexal/vascular necrosis. Histological results show that collagen coagulation progressed from day 0 to day 1, and then stabilized. Results of burn wound imaging using non-invasive techniques were able to produce metrics that correlate to different predictors of burn depth. Collagen coagulation and apoptosis correlated with SFDI scattering coefficient parameter ( μs′) and adnexal/vascular necrosis on the day of burn correlated with blood flow determined by LSI. Therefore, incorporation of SFDI scattering coefficient and blood flow determined by LSI may provide an algorithm for accurate assessment of the severity of burn wounds in real time. PMID:26138371

Epidemiology and outcome analysis of hand burns: A 5-year retrospective review of 378 cases in a burn center in Eastern China.

PubMed

Wang, Kang-an; Sun, Yu; Wu, Guo-sheng; Wang, Yi-ru; Xia, Zhao-fan

2015-11-01

Hands are frequent sites of burn but few related studies were reported in China. The aim of this study was to examine the impacts of gender, age, seasons, place, etiology, total body surface area (TBSA), depth, infection and comorbidities on prognosis following injury in a cohort of hand burn inpatients. This is a retrospective study of total 378 inpatients admitted to the burn center of Changhai hospital from January 2009 to December 2013. The present research showed the male inpatients were predominant and most of the inpatients aged from 20 to 49. Flame (37.04%) and electricity (25.40%) were the major causes of hand burns. Hand burns happened more commonly in work place (60.85%). The study preliminarily pointed out that male, flame and depth were the most significant factors impacting surgery. The main factors relevant to amputation were identified including the electrical burns and other etiology of burns. In addition, depth of hand burns was proved to have a higher impact on length of hospital stay (LOS) than other factors. The results of this study not only provide the necessary information of hand burns in Eastern China but also give the suggestions for the prevention of hand burns. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Sediment record of polycyclic aromatic hydrocarbons in the Liaohe River Delta wetland, Northeast China: Implications for regional population migration and economic development.

PubMed

Ma, Chuanliang; Lin, Tian; Ye, Siyuan; Ding, Xigui; Li, Yuanyuan; Guo, Zhigang

2017-03-01

The polycyclic aromatic hydrocarbons (PAHs) of a 210 Pb-dated sediment core extracted from the Liaohe River Delta wetland were measured to reconstruct the sediment record of PAHs and its response to human activity for the past 300 years in Northeast China. The concentrations of the 16 U.S. Environmental Protection Agency priority PAHs (∑16PAHs) ranged from 46 to 1167 ng g -1 in this sediment core. The concentrations of the 16 PAHs (especially 4- and 5+6-ring PAHs) after the 1980s (surface sediments 0-6 cm) were one or two orders of magnitudes higher than those of the down-core samples. The exponential growth of 4-ring and 5+6-ring PAH concentrations after the 1980s responded well to the increased energy consumption and number of civil vehicles resulting from the rapid economic development in China. Prior to 1950, relatively low levels of the 16 PAHs and a high proportion of 2+3-ring PAHs was indicative of biomass burning as the main source of the PAHs. A significant increase in the 2 + 3 ring PAH concentration from the 1860s-1920s was observed and could be attributed to a constant influx of population migration into Northeast China. It was suggested that the link between historical trend of PAHs and population or energy use involves two different economic stages. Typically, in an agricultural economy, the greater the population size, the greater the emission of PAHs from biomass burning, while in an industrial economy, the increase in sedimentary PAH concentrations is closely related to increasing energy consumption of fossil fuels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Levoglucosan Levels in Alaskan Ice Cores as a Record of Past Wildfires

NASA Astrophysics Data System (ADS)

Dunham, M. E.; Osterberg, E. C.; Kehrwald, N. M.; Kennedy, J.; Ferris, D. G.

2017-12-01

Glaciers in southeast Alaska are significant contributors to global sea-level rise, and therefore understanding the mechanisms driving their recent mass loss is crucial for predicting future sea-level change. Fire activity in Alaska has increased dramatically during the last decade, adding a potential new source of light-absorbing organic material (soot) to the Juneau Icefield that can reduce albedo and enhance surface melt rates. The goal of this project is to create an accurate record of Alaskan wildfires to understand how Alaskan glacial mass balance is affected by the deposition of organic aerosols from wildfires. Previously, oxalate, ammonia, and potassium ion levels have been used as proxies for past wildfire activity, but these ions all have broader emission sources in addition to wildfires. Here we develop a record of past Alaskan fire events and climate from: (1) levels of a biomass burning indicator, levoglucosan, which only forms when cellulose is burned over 300 °C, (2) major ions including oxalate, ammonia, and potassium; (3) the number and size distribution of particles to quantify trace amounts of soot from wildfires; and (4) stable water isotope ratios as a proxy for past temperature in ice cores. We utilize a total of four shallow ice cores, ranging from 7 to 9 m in length, that were collected by a biogeochemistry team during the Juneau Icefield Research Program (JIRP) in 2016. Complications include our limited understanding of the conservation and degradation of levoglucosan over time or during the firnification process. We hypothesize that particle counts will be correlated with levoglucosan peaks, co-varying with wildfire frequency and temperatures over time. Based on previous work, we also expect to find correlations between levoglucosan and oxalate ion concentrations, even though oxalate ions have sources in addition to wildfire activity.

No double detonations but core carbon ignitions in high-resolution, grid-based simulations of binary white dwarf mergers

NASA Astrophysics Data System (ADS)

Fenn, D.; Plewa, T.; Gawryszczak, A.

2016-11-01

We study the violent phase of the merger of massive binary white dwarf systems. Our aim is to characterize the conditions for explosive burning to occur, and identify a possible explosion mechanism of Type Ia supernovae. The primary components of our model systems are carbon-oxygen (C/O) white dwarfs, while the secondaries are made either of C/O or of pure helium. We account for tidal effects in the initial conditions in a self-consistent way, and consider initially well-separated systems with slow inspiral rates. We study the merger evolution using an adaptive mesh refinement, reactive, Eulerian code in three dimensions, assuming symmetry across the orbital plane. We use a corotating reference frame to minimize the effects of numerical diffusion, and solve for self-gravity using a multigrid approach. We find a novel detonation mechanism in C/O mergers with massive primaries. Here, the detonation occurs in the primary's core and relies on the combined action of tidal heating, accretion heating, and self-heating due to nuclear burning. The exploding structure is compositionally stratified, with a reverse shock formed at the surface of the dense ejecta. The existence of such a shock has not been reported elsewhere. The explosion energy (1.6 × 1051 erg) and 56Ni mass (0.86 M⊙) are consistent with an SN Ia at the bright end of the luminosity distribution, with an approximated decline rate of Δm15(B) ≈ 0.99. Our study does not support double-detonation scenarios in the case of a system with a 0.6 M⊙ helium secondary and a 0.9 M⊙ primary. Although the accreted helium detonates, it fails to ignite carbon at the base of the boundary layer or in the primary's core.

MORBIDITY AND SURVIVAL PROBABILITY IN BURN PATIENTS IN MODERN BURN CARE

PubMed Central

Jeschke, Marc G.; Pinto, Ruxandra; Kraft, Robert; Nathens, Avery B.; Finnerty, Celeste C.; Gamelli, Richard L.; Gibran, Nicole S.; Klein, Matthew B.; Arnoldo, Brett D.; Tompkins, Ronald G.; Herndon, David N.

2014-01-01

Objective Characterizing burn sizes that are associated with an increased risk of mortality and morbidity is critical because it would allow identifying patients who might derive the greatest benefit from individualized, experimental, or innovative therapies. Although scores have been established to predict mortality, few data addressing other outcomes exist. The objective of this study was to determine burn sizes that are associated with increased mortality and morbidity after burn. Design and Patients Burn patients were prospectively enrolled as part of the multicenter prospective cohort study, Inflammation and the Host Response to Injury Glue Grant, with the following inclusion criteria: 0–99 years of age, admission within 96 hours after injury, and >20% total body surface area burns requiring at least one surgical intervention. Setting Six major burn centers in North America. Measurements and Main Results Burn size cutoff values were determined for mortality, burn wound infection (at least two infections), sepsis (as defined by ABA sepsis criteria), pneumonia, acute respiratory distress syndrome, and multiple organ failure (DENVER2 score >3) for both children (<16 years) and adults (16–65 years). Five-hundred seventy-three patients were enrolled, of which 226 patients were children. Twenty-three patients were older than 65 years and were excluded from the cutoff analysis. In children, the cutoff burn size for mortality, sepsis, infection, and multiple organ failure was approximately 60% total body surface area burned. In adults, the cutoff for these outcomes was lower, at approximately 40% total body surface area burned. Conclusions In the modern burn care setting, adults with over 40% total body surface area burned and children with over 60% total body surface area burned are at high risk for morbidity and mortality, even in highly specialized centers. PMID:25559438

Military Return to Duty and Civilian Return to Work Factors Following Burns With Focus on the Hand and Literature Review

DTIC Science & Technology

2008-10-01

the three parameters of skin graft - ing, treatment time and presence of a face burn where all reports agree as to the influence of each one of these...cluding the presence of hand burns. Of the studies that agree on factor influence, five document that skin grafting had a significant effect on...stepwise multiple regression analysis, Helm et al determined TBSA to be the stron- gest predictor of RTW followed equally by skin graft - ing and hand burn

Validation of the German version of the Burn Specific Health Scale-Brief (BSHS-B).

PubMed

Müller, Astrid; Smits, Dirk; Jasper, Stefanie; Berg, Lea; Claes, Laurence; Ipaktchi, Ramin; Vogt, Peter M; de Zwaan, Martina

2015-09-01

The Burn Specific Health Scale-Brief (BSHS-B) is recognized as a valid self-rating scale to evaluate quality of life after burn. To validate the translated German version of the BSHS-B. One hundred and forty one burn survivors (65.2% men) with a mean age of 49.62 years (SD=15.16) and a mean duration after burn of 45.01 months (SD=26.18) answered the BSHS-B. Factor structure was tested by using confirmatory factor analysis, reliability (internal consistency) of the scales was determined by means of Cronbach's α. Construct validity was explored through correlations between the BSHS-B and the Short-Form 8 Health Survey (SF-8). In addition, the know-groups technique was used to determine to which degree the BSHS-B discriminates between patients with low and high burn severity based on the abbreviated burn severity index (ABSI). The Hospital Anxiety and Depression Scale (HADS) was used to examine criterion validity. The nine BSHS-B subscales showed good internal consistency. A second-order confirmatory factor analysis revealed the following main components: (1) Affect and Relationship, (2) Function and (3) Skin Involvement. The second-order factors were positively correlated with the SF-8 and negatively correlated with symptoms of anxiety and depression. Patients with low ABSI scored higher on all three BSHS-B domains than those with high ABSI. The results indicate good psychometric properties of the German BSHS-B. Further studies are needed to investigate the utility of the questionnaire in clinical routine practice, evaluation of burn management programs, and burn-specific research. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

The effect of preexisting respiratory co-morbidities on burn outcomes☆

PubMed Central

Knowlin, Laquanda T.; Stanford, Lindsay B.; Cairns, Bruce A.; Charles, Anthony G.

2018-01-01

Introduction Burns cause physiologic changes in multiple organ systems in the body. Burn mortality is usually attributable to pulmonary complications, which can occur in up to 41% of patients admitted to the hospital after burn. Patients with preexisting comorbidities such as chronic lung diseases may be more susceptible. We therefore sought to examine the impact of preexisting respiratory disease on burn outcomes. Methods A retrospective analysis of patients admitted to a regional burn center from 2002–2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA, pre-existing comorbidities, smoker status, length of hospital stay, and days of mechanical ventilation. Bivariate analysis was performed and Cox regression modeling using significant variables was utilized to estimate hazard of progression to mechanical ventilation and mortality. Results There were a total of 7640 patients over the study period. Overall survival rate was 96%. 8% (n=672) had a preexisting respiratory disease. Chronic lung disease patients had a higher mortality rate (7%) compared to those without lung disease (4%, p<0.01). The adjusted Cox regression model to estimate the hazard of progression to mechanical ventilation in patients with respiratory disease was 21% higher compared to those without respiratory disease (HR=1.21, 95% CI=1.01–1.44). The hazard of progression to mortality is 56% higher (HR=1.56, 95% CI=1.10–2.19) for patients with pre-existing respiratory disease compared to those without respiratory disease after controlling for patient demographics and injury characteristics. Conclusion Preexisting chronic respiratory disease significantly increases the hazard of progression to mechanical ventilation and mortality in patients following burn. Given the increasing number of Americans with chronic respiratory diseases, there will likely be a greater number of individuals at risk for worse outcomes following burn. PMID:28341260

The effect of preexisting respiratory co-morbidities on burn outcomes.

PubMed

Knowlin, Laquanda T; Stanford, Lindsay B; Cairns, Bruce A; Charles, Anthony G

2017-03-01

Burns cause physiologic changes in multiple organ systems in the body. Burn mortality is usually attributable to pulmonary complications, which can occur in up to 41% of patients admitted to the hospital after burn. Patients with preexisting comorbidities such as chronic lung diseases may be more susceptible. We therefore sought to examine the impact of preexisting respiratory disease on burn outcomes. A retrospective analysis of patients admitted to a regional burn center from 2002-2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA, pre-existing comorbidities, smoker status, length of hospital stay, and days of mechanical ventilation. Bivariate analysis was performed and Cox regression modeling using significant variables was utilized to estimate hazard of progression to mechanical ventilation and mortality. There were a total of 7640 patients over the study period. Overall survival rate was 96%. 8% (n=672) had a preexisting respiratory disease. Chronic lung disease patients had a higher mortality rate (7%) compared to those without lung disease (4%, p<0.01). The adjusted Cox regression model to estimate the hazard of progression to mechanical ventilation in patients with respiratory disease was 21% higher compared to those without respiratory disease (HR=1.21, 95% CI=1.01-1.44). The hazard of progression to mortality is 56% higher (HR=1.56, 95% CI=1.10-2.19) for patients with pre-existing respiratory disease compared to those without respiratory disease after controlling for patient demographics and injury characteristics. Preexisting chronic respiratory disease significantly increases the hazard of progression to mechanical ventilation and mortality in patients following burn. Given the increasing number of Americans with chronic respiratory diseases, there will likely be a greater number of individuals at risk for worse outcomes following burn. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Burn mortality in patients with preexisting cardiovascular disease.

PubMed

Knowlin, Laquanda; Reid, Trista; Williams, Felicia; Cairns, Bruce; Charles, Anthony

2017-08-01

Burn shock, a complex process, which develops following burn leads to severe and unique derangement of cardiovascular function. Patients with preexisting comorbidities such as cardiovascular diseases may be more susceptible. We therefore sought to examine the impact of preexisting cardiovascular disease on burn outcomes. A retrospective analysis of patients admitted to a regional burn center from 2002 to 2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA, pre-existing comorbidities, and length of ICU/hospital stay. Bivariate analysis was performed and Poisson regression modeling was utilized to estimate the incidence of being in the ICU and mortality. There were a total of 5332 adult patients admitted over the study period. 6% (n=428) had a preexisting cardiovascular disease. Cardiovascular disease patients had a higher mortality rate (16%) compared to those without cardiovascular disease (3%, p<0.001). The adjusted Poisson regression model to estimate incidence risk of being in intensive care unit in patients with cardiovascular disease was 33% higher compared to those without cardiovascular disease (IRR=1.33, 95% CI=1.22-1.47). The risk for mortality is 42% higher (IRR=1.42, 95% CI=1.10-1.84) for patients with pre-existing cardiovascular disease compared to those without cardiovascular disease after controlling for other covariates. Preexisting cardiovascular disease significantly increases the risk of intensive care unit admission and mortality in burn patients. Given the increasing number of Americans with cardiovascular diseases, there will likely be a greater number of individuals at risk for worse outcomes following burn. This knowledge can help with burn prognostication. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Reepithelialization of mid-dermal porcine burns after rapid enzymatic debridement with Debrase®.

PubMed

Singer, Adam J; Taira, Breena R; Anderson, Ryon; McClain, Steve A; Rosenberg, Lior

2011-01-01

Reepithelialization of mid-dermal burns is delayed by the presence of a layer of necrotic eschar. The authors hypothesized that rapid selective debridement using an enzymatic bromelain-based preparation, Debrase®, would speed reepithelialization. Forty mid-dermal burns (2.5 × 2.5 cm) were created on the back and flanks of two anesthetized domestic pigs (25 kg) using an aluminum bar (150 g) preheated in hot water (80°C) and applied for 20 seconds. The burns were randomized to a 4-hour topical application of Debrase® (n = 20) or its vehicle (n = 20) followed by daily application of a petrolatum-based triple antibiotic. Wounds were visualized and photographed daily for evidence of reepithelialization. Reepithelialization was considered complete when the entire wound was opaque and dry when blotted with tissue paper. 4-mm full-thickness biopsies were obtained for histological analysis using hematoxylin and eosin staining by a board-certified dermatopathologist masked to the burn therapy at 7, 9, 11, and 13 days after injury. The primary outcome was time to complete reepithelialization of the burns. Secondary outcomes were the percentage of burns that were reepithelialized at days 7, 11, and 13 and the mean percentage reepithelialization on microscopic analysis. A sample of 20 burns in each group had 80% power to detect a 2-day difference in the time to complete reepithelialization (two-tailed, P < .05). Application of Debrase®, but not the control vehicle, resulted in dissolution of the necrotic upper dermis in all treated burns. The mean time to complete reepithelialization was faster for Debrase®-treated (7.4 ± 0.8 days) than control-treated (9.1 ± 2.1 days) burns: difference, 1.7 days (95% confidence interval, 0.5-2.9). The percentage of completely reepithelialized Debrase®- and control-treated burns were day 7, 65.0 vs 25.0% (P = .02); day 9, 80.0 vs 40.0% (P = .02); and day 11, 100.0 vs 92.0% (P = .45). Treatment of mid-dermal porcine burns with a single topical application of Debrase® results in earlier wound reepithelialization.

Removal of NOx and NOy in biomass burning plumes in the boundary layer over northern Australia

NASA Astrophysics Data System (ADS)

Takegawa, N.; Kondo, Y.; Koike, M.; Ko, M.; Kita, K.; Blake, D. R.; Nishi, N.; Hu, W.; Liley, J. B.; Kawakami, S.; Shirai, T.; Miyazaki, Y.; Ikeda, H.; Russel-Smith, J.; Ogawa, T.

2003-05-01

The Biomass Burning and Lightning Experiment Phase B (BIBLE-B) aircraft measurement campaign was conducted over the western Pacific and Australia in August and September 1999. In situ aircraft measurements of carbon monoxide (CO), nitric oxide (NO), total reactive nitrogen (NOy), ozone (O3), nonmethane hydrocarbons (NMHCs), and other species were made during BIBLE-B. Meteorological analysis shows that the trace gases emitted from biomass burning in northern Australia were mostly confined within the planetary boundary layer (below ˜3 km) by strong subsidence in the free troposphere. Removal processes of NOx (equal to measured NO + calculated NO2) and NOy in biomass burning plumes in the boundary layer are examined on the basis of correlation analysis. The photochemical lifetime of NOx in biomass burning plumes during the daytime is estimated to be 0.1 to 0.3 days using the correlations of NOx with short-lived NMHCs and hydroxyl radical (OH) concentration calculated from a constrained photochemical model. Correlation of NOy with CO shows that ˜60% of the NOy molecules originating from biomass burning were removed in the boundary layer within 2-3 days. This result is consistent with dry deposition of nitric acid (HNO3) in the plumes. It is likely that only a small fraction of NOy emitted from biomass burning was exported from the boundary layer to the free troposphere during the BIBLE-B period.

Burn epidemiology and cost of medication in paediatric burn patients.

PubMed

Koç, Zeliha; Sağlam, Zeynep

2012-09-01

Burns are common injuries that cause problems to societies throughout the world. In order to reduce the cost of burn treatment in children, it is extremely important to determine the burn epidemiology and the cost of medicines used in burn treatment. The present study used a retrospective design, with data collected from medical records of 140 paediatric patients admitted to a burn centre between 1 January 2009 and 31 December 2009. Medical records were examined to determine burn epidemiology, medication administered, dosage, and duration of use. Descriptive statistical analysis was completed for all variables; chi-square was used to examine the relationship between certain variables. It was found that 62.7% of paediatric burns occur in the kitchen, with 70.7% involving boiling water; 55.7% of cases resulted in third-degree burns, 19.3% required grafting, and mean duration of hospital stay was 27.5 ± 1.2 days. Medication costs varied between $1.38 US dollars (USD) and $14,159.09, total drug cost was $46,148.03 and average cost per patient was $329.63. In this study, the medication cost for burn patients was found to be relatively high, with antibiotics comprising the vast majority of medication expenditure. Most paediatric burns are preventable, so it is vital to educate families about potential household hazards that can be addressed to reduce the risk of a burn. Programmes are also recommended to reduce costs and the inappropriate prescribing of medication. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

A One-Dimensional Global-Scaling Erosive Burning Model Informed by Blowing Wall Turbulence

NASA Technical Reports Server (NTRS)

Kibbey, Timothy P.

2014-01-01

A derivation of turbulent flow parameters, combined with data from erosive burning test motors and blowing wall tests results in erosive burning model candidates useful in one-dimensional internal ballistics analysis capable of scaling across wide ranges of motor size. The real-time burn rate data comes from three test campaigns of subscale segmented solid rocket motors tested at two facilities. The flow theory admits the important effect of the blowing wall on the turbulent friction coefficient by using blowing wall data to determine the blowing wall friction coefficient. The erosive burning behavior of full-scale motors is now predicted more closely than with other recent models.

Quantitative Methods for Analysing Joint Questionnaire Data: Exploring the Role of Joint in Force Design

DTIC Science & Technology

2015-08-01

the nine questions. The Statistical Package for the Social Sciences ( SPSS ) [11] was used to conduct statistical analysis on the sample. Two types...constructs. SPSS was again used to conduct statistical analysis on the sample. This time factor analysis was conducted. Factor analysis attempts to...Business Research Methods and Statistics using SPSS . P432. 11 IBM SPSS Statistics . (2012) 12 Burns, R.B., Burns, R.A. (2008) ‘Business Research

Effect of parenteral glutamine supplementation combined with enteral nutrition on Hsp90 expression and lymphoid organ apoptosis in severely burned rats.

PubMed

Fan, Jun; Wu, Jing; Wu, Li-Dong; Li, Guo-Ping; Xiong, Meng; Chen, Xi; Meng, Qing-Yan

2016-11-01

The aim of this study is to investigate the effects of parenteral glutamine(GLN) supplementation combined with enteral nutrition (EN) on heat shock protein 90(Hsp90) expression, apoptosis of lymphoid organs and circulating lymphocytes, immunological function and survival in severely burned rats. Male SD rats were randomly assigned into 4 groups: a sham burn+EN+GLN-free amino acid (AA) group (n=10), a sham burn+EN+GLN group (n=10), a burn+EN+AA group (n=10), and a burn +EN +GLN group (n=10). Two hours after a 30% total body surface area (TBSA), full-thickness scald burn injury on the back was made, the burned rats in two experimental groups (the burn+EN+AA group and the burn+EN +GLN group) were fed with a conventional enteral nutrition solution by oral gavage for 7 days. Simultaneously, the rats in the burn+EN+GLN group were given 0.35g GLN/kg body weight/day once via a tail vein injection for 7 days, whereas those in the burn+EN+AA group were administered isocaloric/isonitrogenous GLN-free amino acid solution (Tyrosine) for comparison. The rats in two sham burn control groups (the sham burn+EN+AA group and the sham burn+EN +GLN group) were treated in the same procedure as above, except for burn injury. All rats in each of the four groups were given 175kcal/kg body wt/day. There was isonitrogenous, isovolumic and isocaloric intake among four groups. At the end of the 7th day after nutritional programme were finished, all rats were anesthetized and samples were collected for further analysis. Serum immunoglobulin quantification was conducted by ELISA. Circulating lymphocyte numbers were counted by Coulter LH-750 Analyzer. The percentages and apoptotic ratio of CD4 and CD8T lymphocytes in circulation were determined by flow cytometry (FCM). The neutrophil phagocytosis index (NPI) was examined. The GLN concentrations in plasma, thymus, spleen and skeletal muscle were measured by high performance liquid chromatography (HPLC). The organ index evaluation and TUNEL analysis of thymus and spleen were carried out. The expression of Hsp90 in thymus and spleen was analyzed by western blotting. Moreover, the survival in burned rats was observed. The results revealed that parenteral GLN supplementation combined with EN significantly increased the GLN concentrations of plasma and tissues, the serum immunoglobulin content, the circulating lymphocyte number, the CD4/CD8 ratio, the indexes of thymus and spleen, NPI and survival as compared with the burn+EN+AA group (p<0.05). The expression of Hsp90 in thymus and spleen in the burn+EN+GLN group was significantly up-regulated as compared with the burn+EN+AA group (p<0.05). The apoptosis in circulating CD4 and CD8 lymphocytes, thymus and spleen in the burn+EN+GLN group was significantly decreased as compared with the burn+EN+AA group (p<0.05). The results of this study show that parenteral GLN supplementation combined with EN may increase the GLN concentrations of plasma and tissues, up-regulate the expression of Hsp90, attenuate apoptosis in lymphoid organ and circulating lymphocyte, enhance the immunological function and improve survival in severely burned rats. Clinically, therapeutic efforts at the modulation of the immune dysfunction may contribute to a favorable outcome in severely burned patients. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

The advantages of the application of amnion membrane in the treatment of burns.

PubMed

Andonovska, D; Dzokic, Gj; Spasevska, L; Trajkovska, T; Popovska, K; Todorov, I; Petrovski, P; Kondov, G; Sapova, B; Marcikic, G; Atanasova, E; Obocki, E; Ugrinovska, J; Andonovski, D; Andonovski, D; Vasilevska, V; Mircevska-Zogovska, E

2008-07-01

A crucial and important factor for successful treatment of burns is the early covering of the burned area with skin substitutes. The covering of the burn requires material that restores the epidermal function and integrates itself into the process of healing. Biological dressings are the golden standard for the temporary covering of burns. All biological skin substitutes are susceptible to early graft reaction and the only exception is the amnion membrane. The importance of the amnion membrane as a biological dressing for burns amounts to: a barrier to bacterial colonization, hastens the epithelisation, and control of water loss. Amnioplasty is a method of application of amnion membrane on the recipient site. In this comparative study, 60 patients with dermal and sub-dermal burns were included. Research was made on an examination group of 30 patients with burns where the method of amnioplasty was applied, and for this amnion membrane conserved in 76% alcohol was used. The control group was made up of 30 patients with burns treated conventionally, and standard methods for the local treatment of burns were applied: exposition, occlusive dressing and initial excision with skin grafting. Pathohistological and microbiological analyses of the bioptical material were made. The degree of the burns was determined through a pathohistological analysis of the bioptical material taken the third day, and in some of the subjects where re-epithelialization was determined on the seventh day, the further re-epithelialization was observed clinically. Pathohistological examination enabled discrimination between bacterial colonization and the invasive bacterial infection. Furthermore, the type of bacterial colonization and infection was determined, which was confirmed with microbiological analysis. The analysis of the results from the microbiological and pathohistological researches of the bioptical material according to the bacterial colonization and infection showed that, although between the examined and the control group there was no statistically important difference, the value of p = 0.067 is close to the statistically important value of p < 0.05. The results of the pathohistological examination of the bioptical material taken the seventh day and analysed according to the re-epithelialization showed that there was a significant difference between the two groups of p < 0.035. It should be mentioned that, although according to the microbiological examinations of the bioptical material a statistically significant difference was not achieved, clinical significance was achieved. The obtained significance of p < 0.035 compared to the re-epithelialization in both groups approved the application of the method of amnioplasty. The histological analysis of the bioptical material not only determines the degree of the burns specifically, but facilitates the choice of method for further treatment, observes the speed of the re-epithelialization and plays an important part in the correct diagnosis and the early start of the specific therapy, important in preventing sepsis. The application of amnion membrane as a biological dressing speeds the re-epithelialization and prevents invasive bacterial infection. Pathohistological examination of the burns is recommended to be established as a standard method in clinical practice.

Evaluating the socioeconomic and cultural factors associated with pediatric burn injuries in Maputo, Mozambique.

PubMed

Karan, Abraar; Amado, Vanda; Vitorino, Pio; Kulber, David; Taela, Atanasio; DeUgarte, Daniel A

2015-11-01

Pediatric burn injuries are one of the leading causes of preventable morbidity and mortality in Sub-Saharan Africa. Research on the complex system of social, economic and cultural factors contributing to burn injuries in this setting is much needed. We conducted a prospective questionnaire-based analysis of pediatric burn patients presenting to the Hospital Central de Maputo. A total of 39 patients were included in the study. Interviews were conducted with the children's caretakers by two trained medical students at the Eduardo Mondlane Medical School in Maputo with the aid of local nursing staff. Most burns occurred from scald wounds (26/39) particularly from bathwater, followed by fire burns (11/39). Burns occurred more frequently in the afternoon (16/39) and evening (16/39). Over one quarter of burns (9/33) occurred in the absence of a caretaker. One-third (12/36) of participants attempted to treat the burn at home prior to bringing the child into the hospital, and roughly two-thirds (24/37) reported using traditional remedies for burn care. The average household had just 2 rooms for an average of 5 family members. Most burns were second degree (25/37). Prevention efforts in this setting are much needed and can be implemented taking complex cultural and social factors into account. Education regarding regulation of water temperature for baths is important, given the prevalence of scald burns. Moreover, the introduction of low-cost, safer cooking technology can help mitigate inhalation injury and reduce fire burns. Additionally, burn care systems must be integrated with local traditional medical interventions to respect local cultural medicinal practices.

An analysis of burn-off impact on the structure microporous of activated carbons formation

NASA Astrophysics Data System (ADS)

Kwiatkowski, Mirosław; Kopac, Türkan

2017-12-01

The paper presents the results on the application of the LBET numerical method as a tool for analysis of the microporous structure of activated carbons obtained from a bituminous coal. The LBET method was employed particularly to evaluate the impact of the burn-off on the obtained microporous structure parameters of activated carbons.

40 CFR 63.11211 - How do I demonstrate initial compliance with the emission limits?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Table 4 to this subpart, conducting a fuel analysis for each type of fuel burned in your boiler... single type of fuel, you are exempted from the compliance requirements of conducting a fuel analysis for each type of fuel burned in your boiler. For purposes of this subpart, boilers that use a supplemental...

40 CFR 63.11211 - How do I demonstrate initial compliance with the emission limits?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Table 4 to this subpart, conducting a fuel analysis for each type of fuel burned in your boiler... single type of fuel, you are exempted from the compliance requirements of conducting a fuel analysis for each type of fuel burned in your boiler. For purposes of this subpart, boilers that use a supplemental...

Biomass burning emissions of reactive gases estimated from satellite data analysis and ecosystem modeling for the Brazilian Amazon region

NASA Astrophysics Data System (ADS)

Potter, Christopher; Brooks-Genovese, Vanessa; Klooster, Steven; Torregrosa, Alicia

2002-10-01

To produce a new daily record of trace gas emissions from biomass burning events for the Brazilian Legal Amazon, we have combined satellite advanced very high resolution radiometer (AVHRR) data on fire counts together for the first time with vegetation greenness imagery as inputs to an ecosystem biomass model at 8 km spatial resolution. This analysis goes beyond previous estimates for reactive gas emissions from Amazon fires, owing to a more detailed geographic distribution estimate of vegetation biomass, coupled with daily fire activity for the region (original 1 km resolution), and inclusion of fire effects in extensive areas of the Legal Amazon (defined as the Brazilian states of Acre, Amapá, Amazonas, Maranhao, Mato Grosso, Pará, Rondônia, Roraima, and Tocantins) covered by open woodland, secondary forests, savanna, and pasture vegetation. Results from our emissions model indicate that annual emissions from Amazon deforestation and biomass burning in the early 1990s total to 102 Tg yr-1 carbon monoxide (CO) and 3.5 Tg yr-1 nitrogen oxides (NOx). Peak daily burning emissions, which occurred in early September 1992, were estimated at slightly more than 3 Tg d-1for CO and 0.1 Tg d-1for NOx flux to the atmosphere. Other burning source fluxes of gases with relatively high emission factors are reported, including methane (CH4), nonmethane hydrocarbons (NMHC), and sulfur dioxide (SO2), in addition to total particulate matter (TPM). We estimate the Brazilian Amazon region to be a source of between one fifth and one third for each of these global emission fluxes to the atmosphere. The regional distribution of burning emissions appears to be highest in the Brazilian states of Maranhao and Tocantins, mainly from burning outside of moist forest areas, and in Pará and Mato Grosso, where we identify important contributions from primary forest cutting and burning. These new daily emission estimates of reactive gases from biomass burning fluxes are designed to be used as detailed spatial and temporal inputs to computer models and data analysis of tropospheric chemistry over the tropical region.

Goal-Directed Fluid Resuscitation Protocol Based on Arterial Waveform Analysis of Major Burn Patients in a Mass Burn Casualty.

PubMed

Chiao, Hao-Yu; Chou, Chang-Yi; Tzeng, Yuan-Sheng; Wang, Chih-Hsin; Chen, Shyi-Gen; Dai, Niann-Tzyy

2018-02-01

Adequate fluid titration during the initial resuscitation period of major burn patients is crucial. This study aimed to evaluate the feasibility and efficacy of a goal-directed fluid resuscitation protocol that used hourly urine output plus the arterial waveform analysis FloTrac (Edwards LifeSciences, Irvine, Calif) system for major burns to avoid fluid overload. We conducted a retrospective cohort study of 43 major burn patients at the Tri-Service General Hospital after the Formosa Fun Coast Dust Explosion on June 27, 2015. Because of the limited capacity of intensive care units (ICUs), 23 intubated patients were transferred from the burn wards or emergency department to the ICU within 24 hours. Fluid administration was adjusted to achieve a urine output of 30 to 50 mL/h, cardiac index greater than 2.5 L/min/m, and stroke volume variation (SVV) less than 12%. The hourly crystalloid fluid infusion rate was titrated based on SVV and hourly urine output. Of the 23 critically burned patients admitted to the ICU, 13 patients who followed the goal-directed fluid resuscitation protocol within 12 hours postburn were included in the analysis. The mean age (years) was 21.8, and the mean total body surface area (TBSA) burned (%) was 68.0. The mean Revised Baux score was 106.8. All patients sustained inhalation injury. The fluid volumes administered to patients in the first 24 hours and the second 24 hours (mL/kg/% total body surface area) were 3.62 ± 1.23 and 2.89 ± 0.79, respectively. The urine outputs in the first 24 hours and the second 24 hours (mL/kg/h) were 1.13 ± 0.66 and 1.53 ± 0.87, respectively. All patients achieved the established goals within 32 hours postburn. In-hospital mortality rate was 0%. The SVV-based goal-directed fluid resuscitation protocol leads to less unnecessary fluid administration during the early resuscitation phase. Clinicians can efficaciously manage the dynamic body fluid changes in major burn patients under the guidance of the protocol.

Mapping Soil Carbon in the Yukon Kuskokwim River Delta Alaska

NASA Astrophysics Data System (ADS)

Natali, S.; Fiske, G.; Schade, J. D.; Mann, P. J.; Holmes, R. M.; Ludwig, S.; Melton, S.; Sae-lim, N.; Jardine, L. E.; Navarro-Perez, E.

2017-12-01

Arctic river deltas are hotspots for carbon storage, occupying <1% of the pan-Arctic watershed but containing >10% of carbon stored in arctic permafrost. The Yukon Kuskokwim (YK) Delta, Alaska is located in the lower latitudinal range of the northern permafrost region in an area of relatively warm permafrost that is particularly vulnerable to warming climate. Active layer depths range from 50 cm on peat plateaus to >100 cm in wetland and aquatic ecosystems. The size of the soil organic carbon pool and vulnerability of the carbon in the YK Delta is a major unknown and is critically important as climate warming and increasing fire frequency may make this carbon vulnerable to transport to aquatic and marine systems and the atmosphere. To characterize the size and distribution of soil carbon pools in the YK Delta, we mapped the land cover of a 1910 km2 watershed located in a region of the YK Delta that was impacted by fire in 2015. The map product was the result of an unsupervised classification using the Weka K Means clustering algorithm implemented in Google's Earth Engine. Inputs to the classification were Worldview2 resolution optical imagery (1m), Arctic DEM (5m), and Sentinel 2 level 1C multispectral imagery, including NDVI, (10 m). We collected 100 soil cores (0-30 cm) from sites of different land cover and landscape position, including moist and dry peat plateaus, high and low intensity burned plateaus, fens, and drained lakes; 13 lake sediment cores (0-50 cm); and 20 surface permafrost cores (to 100 cm) from burned and unburned peat plateaus. Active layer and permafrost soils were analyzed for organic matter content, soil moisture content, and carbon and nitrogen pools (30 and 100 cm). Soil carbon content varied across the landscape; average carbon content values for lake sediments were 12% (5- 17% range), fens 26% (9-44%), unburned peat plateaus 41% (34-44%), burned peat plateaus 19% (7-34%). These values will be used to estimate soil carbon pools, which will be applied to the spatial extent of each landcover class in our map, yielding a watershed-wide and spatially explicit map of soil carbon in the YK Delta. This map will provide the basis for understanding where carbon is stored in the watershed and the vulnerability of that carbon to climate change and fire.

Interstellar Lithium and Rubidium in the Diffuse Gas Near IC 443

NASA Astrophysics Data System (ADS)

Ritchey, Adam M.; Taylor, C. J.; Federman, S. R.; Lambert, D. L.

2011-01-01

We present an analysis of interstellar lithium and rubidium from observations made with the Hobby-Eberly Telescope at McDonald Observatory of the Li I λ6707 and Rb I λ7800 absorption lines along four lines of sight through the supernova remnant IC 443. The observations probe interstellar material polluted by the ejecta of a core-collapse (Type II) supernova and can thus be used to constrain the contribution from massive stars to the synthesis of lithium and rubidium. Production of 7Li is expected to occur through neutrino spallation in the helium and carbon shells of the progenitor star during the terminal supernova explosion, while both 6Li and 7Li are synthesized via spallation and fusion reactions involving cosmic rays accelerated by the remnant. Gamma-ray emission from IC 443 provides strong evidence for the interaction of accelerated cosmic rays with the ambient atomic and molecular gas. Rubidium is also produced by massive stars through the weak s-process in the He- and C-burning shells and the r-process during core collapse. We examine interstellar 7Li/6Li isotope ratios as well as Li/K and Rb/K ratios along each line of sight, and discuss the implications of our results in the context of nucleosynthesis associated with Type II supernovae.

Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

DOE PAGES

Hansen, Stephanie B.; Harding, Eric C.; Knapp, Patrick F.; ...

2018-03-07

The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. In this work, we show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated bymore » the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Lastly, analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 10 24 e/cm 3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.« less

Which evolutionary status does the Blue Large-Amplitude Pulsators stay at?

NASA Astrophysics Data System (ADS)

Wu, Tao; Li, Yan

2018-05-01

Asteroseismology is a very useful tool for exploring the stellar interiors and evolutionary status and for determining stellar fundamental parameters, such as stellar mass, radius, surface gravity, and the stellar mean density. In the present work, we use it to preliminarily analyze the 14 new-type pulsating stars: Blue Large-Amplitude Pulsators (BLAPs) which is observed by OGLE project, to roughly analyze their evolutionary status. We adopt the theory of single star evolution and artificially set the mass loss rate of \\dot{M}=-2× 10^{-4} M_{⊙}/year and mass loss beginning at the radius of R = 40 R_{⊙} on red giant branch to generate a series of theoretical models. Based on these theoretical models and the corresponding observations, we find that those BLAP stars are more likely to be the core helium burning stars. Most of them are in the middle and late phase of the helium burning.

Overview of the NASA Environmentally Responsible Aviation Project's Propulsion Technology Portfolio

NASA Technical Reports Server (NTRS)

Suder, Kenneth L.

2012-01-01

The NASA Environmentally Responsible Aviation (ERA) Project is focused on developing and demonstrating integrated systems technologies to TRL 4-6 by 2020 that enable reduced fuel burn, emissions, and noise for futuristic air vehicles. The specific goals aim to simultaneously reduce fuel burn by 50%, reduce Landing and Take-off Nitrous Oxides emissions by 75% relative to the CAEP 6 guidelines, and reduce cumulative noise by 42 Decibels relative to the Stage 4 guidelines. These goals apply to the integrated vehicle and propulsion system and are based on a reference mission of 3000nm flight of a Boeing 777-200 with GE90 engines. This paper will focus primarily on the ERA propulsion technology portfolio, which consists of advanced combustion, propulsor, and core technologies to enable these integrated air vehicle systems goals. An overview of the ERA propulsion technologies will be described and the status and results to date will be presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clausen, Drew; Wade, Richard A., E-mail: dclausen@astro.psu.edu, E-mail: wade@astro.psu.edu

Many hot subdwarf B stars (sdBs) are in close binaries, and the favored formation channels for subdwarfs rely on mass transfer in a binary system to strip a core He-burning star of its envelope. However, these channels cannot account for sdBs that have been observed in long-period binaries nor the narrow mass distribution of isolated (or 'singleton') sdBs. We propose a new formation channel involving the merger of a helium white dwarf and a low-mass, hydrogen-burning star, which addresses these issues. Hierarchical triples whose inner binaries merge and form sdBs by this process could explain the observed long-period subdwarf+main-sequence binaries.more » This process would also naturally explain the observed slow rotational speeds of singleton sdBs. We also briefly discuss the implications of this formation channel for extreme horizontal branch morphology in globular clusters and the UV upturn in elliptical galaxies.« less

Ignition and Combustion of Bulk Metals in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Branch, Melvyn C.; Daily, John W.; Abbud-Madrid, Angel

1999-01-01

Results of a study of heterogeneous and homogeneous combustion of metals in reduced gravity are presented. Cylindrical titanium and magnesium samples are radiatively ignited in pure-oxygen at 1 atm. Qualitative observations, propagation rates, and burning times are extracted from high-speed cinematography. Time-resolved emission spectra of gas-phase reactions are acquired with an imaging spectrograph. Lower propagation rates of the reacting mass on titanium and of ignition waves on magnesium are obtained at reduced gravity. These rates are compared to theoretical results from fire-spread analyses with a diffusion/convection controlled reaction. The close agreement found between experimental and theoretical propagation rates indicates the strong influence of natural-convection-enhanced oxygen transp6rt on burning rates. Lower oxygen flux and lack of condensed product removal appear to be responsible for longer burning times of magnesium gas-phase diffusion flames in reduced gravity. Spherically symmetric explosions in magnesium flames at reduced gravity (termed radiation-induced metal explosions, or RIME) may be driven by increased radiation heat transfer from accumulated condensed products to an evaporating metal core covered by a porous, flexible oxide coating. In titanium specimens, predominantly heterogeneous burning characterizes the initial steady propagation of the molten mass, while homogeneous gas-phase reactions are detected around particles ejected from the molten mixture. In magnesium specimens, band and line reversal of all the UV spectral systems of Mg and MgO are attributed to the interaction between small oxide particles and the principal gaseous emitters.

Landsat-Based Detection and Severity Analysis of Burned Sugarcane Plots in Tarlac, Philippines Using Differenced Normalized Burn Ratio (dNBR)

NASA Astrophysics Data System (ADS)

Baloloy, A. B.; Blanco, A. C.; Gana, B. S.; Sta. Ana, R. C.; Olalia, L. C.

2016-09-01

The Philippines has a booming sugarcane industry contributing about PHP 70 billion annually to the local economy through raw sugar, molasses and bioethanol production (SRA, 2012). Sugarcane planters adapt different farm practices in cultivating sugarcane, one of which is cane burning to eliminate unwanted plant material and facilitate easier harvest. Information on burned sugarcane extent is significant in yield estimation models to calculate total sugar lost during harvest. Pre-harvest burning can lessen sucrose by 2.7% - 5% of the potential yield (Gomez, et al 2006; Hiranyavasit, 2016). This study employs a method for detecting burn sugarcane area and determining burn severity through Differenced Normalized Burn Ratio (dNBR) using Landsat 8 Images acquired during the late milling season in Tarlac, Philippines. Total burned area was computed per burn severity based on pre-fire and post-fire images. Results show that 75.38% of the total sugarcane fields in Tarlac were burned with post-fire regrowth; 16.61% were recently burned; and only 8.01% were unburned. The monthly dNBR for February to March generated the largest area with low severity burn (1,436 ha) and high severity burn (31.14 ha) due to pre-harvest burning. Post-fire regrowth is highest in April to May when previously burned areas were already replanted with sugarcane. The maximum dNBR of the entire late milling season (February to May) recorded larger extent of areas with high and low post-fire regrowth compared to areas with low, moderate and high burn severity. Normalized Difference Vegetation Index (NDVI) was used to analyse vegetation dynamics between the burn severity classes. Significant positive correlation, rho = 0.99, was observed between dNBR and dNDVI at 5% level (p = 0.004). An accuracy of 89.03% was calculated for the Landsat-derived NBR validated using actual mill data for crop year 2015-2016.

Usage of density analysis based on micro-CT for studying lung injury associated with burn-blast combined injury.

PubMed

Chang, Yang; Zhang, Dong-Hai; Hu, Quan; Liu, Ling-Ying; Yu, Yong-Hui; Chai, Jia-Ke

2018-02-12

Burn-blast combined injury is a kind of injury caused by heat and blast at the same time. The lung injury after burn-blast combined injuries is of primary importance, and investigation of lung injury is needed in the clinical care of patients. Computed tomography (CT) is one of the standard tools used to observe the anatomical basis and pathophysiology of acute lung injury. We applied a method of fast 3D (three-dimensional) reconstruction to calculate the density value of the lung injury by CT analysis. Blast-injury group (BL group), burn-injury group (B group), burn-blast combined injury group (BBL group), and sham control group (C group) were established. Each group had 16 rats. The three-dimensional images of the lung tissue were obtained at 6h, 24h, and 48h according to the CT value. The average density of the whole lung, left lung, and right lung were measured. The lung tissues were paraffin-embedded and HE stained. Smith scoring was performed according to the pathological findings. In the BBL group, the density of the lung tissue was higher than those of the BL group and B group (P<0.01). The lung tissue density values at 24h after injury were higher than those at 6h and 48h after injury (P<0.01). Pathological results confirmed the changes of density analysis of the lung tissue. The results have indicated that density analysis through a CT scan can be used as a way to evaluate lung injury in a burn-blast injury. Copyright © 2018 Elsevier Ltd and ISBI. All rights reserved.

A population-based study of the epidemiology of acute adult burns in Ecuador from 2005 to 2014.

PubMed

Ortiz-Prado, Esteban; Armijos, Luciana; Iturralde, Ana Lucia

2015-05-01

To describe the demographic, risk factor, occupational, and morbidity and mortality characteristics of burns in adults in Ecuador using national data. These data are from the only specialized public hospital in Ecuador that has a 12-bed burn unit. The National Institute of Statistics and Census provided data from the burn unit of the Hospital Eugenio Espejo, in Quito. Three different datasets pertaining to burn deaths, burn unit inpatient admissions, and hospital discharge were analyzed. Patients who died or were discharged before entering the burn unit were not included in this analysis. During the 10-year period, 1106 patients were admitted to the burn unit, men represent 69.37% with 768 cases and women represent 30.62% with 337 patients; the number of patients per year was on average 123 cases; the average age was 33-34 years old, with a range between 16 and 96 years old. Heat (thermal) burns represent 65.78% followed by electrical with 30.53%, friction burns with 2.06%, and chemical burns with 1.62%. Domestic methane gas was the most frequent agent causing thermal burns and the most affected occupational groups are construction workers and people who stay at home. The overall mortality is 10.2% and the average length of stay was 23 days. Thermal burns are more frequent than any other cause of burns. Electrical burns are more frequent in Ecuador than anywhere else according to our research, meaning that control and prevention of workplace safety, urban planning, and home safety are scarce. The most affected groups are those dedicated to labor work. Finally, mortality in hospitalized patient is higher when compared with developed countries. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Healthcare resource utilization and epidemiology of pediatric burn-associated hospitalizations, United States, 2000.

PubMed

Shields, Brenda J; Comstock, R Dawn; Fernandez, Soledad A; Xiang, Huiyun; Smith, Gary A

2007-01-01

The objective of this study was to describe the epidemiology and financial burden of burn-associated hospitalizations for children younger than 18 years in the United States. Retrospective data analysis of pediatric burn-associated hospitalizations was done using the Healthcare Cost and Utilization Project Kids' Inpatient Database for 2000. An estimated 10,000 children younger than 18 years were hospitalized for burn-associated injuries in the United States in 2000. These children spent an estimated 66,200 days in the hospital with associated hospital charges equal to USD 211,772,700. Total charges and length of stay for pediatric burn-associated hospitalizations in the United States during 2000 were associated with degree of burn, percentage of total body surface area burned, child's age, region of the United States, hospital location, and hospital type. Children 2 years old or younger were more likely to be nonwhite, be hospitalized for burns, and burn their hands/wrists, compared with children 3 to 17 years of age. Male children in both age groups were more likely to be hospitalized for burns than female children. Children 2 years old or younger were more likely to be burned by hot liquids/vapors and contact with hot substances/objects, while children 3 to 17 years were more likely to be burned by fire/flames. This study is the first national study on healthcare resource utilization for pediatric burn-associated hospitalizations to utilize the KID database. Burns are a major source of pediatric morbidity and are associated with significant national healthcare resource utilization annually. Future burn prevention efforts should emphasize implementing passive injury prevention strategies, especially for young children who are nonwhite and live in low-income communities.

ER stress and subsequent activated calpain play a pivotal role in skeletal muscle wasting after severe burn injury

PubMed Central

Shen, Chuanan; Li, Dawei; Wang, Xiaoteng

2017-01-01

Severe burns are typically followed by hypermetabolism characterized by significant muscle wasting, which causes considerable morbidity and mortality. The aim of the present study was to explore the underlying mechanisms of skeletal muscle damage/wasting post-burn. Rats were randomized to the sham, sham+4-phenylbutyrate (4-PBA, a pharmacological chaperone promoting endoplasmic reticulum (ER) folding/trafficking, commonly considered as an inhibitor of ER), burn (30% total body surface area), and burn+4-PBA groups; and sacrificed at 1, 4, 7, 14 days after the burn injury. Tibial anterior muscle was harvested for transmission electron microscopy, calcium imaging, gene expression and protein analysis of ER stress / ubiquitin-proteasome system / autophagy, and calpain activity measurement. The results showed that ER stress markers were increased in the burn group compared with the sham group, especially at post-burn days 4 and 7, which might consequently elevate cytoplasmic calcium concentration, promote calpain production as well as activation, and cause skeletal muscle damage/wasting of TA muscle after severe burn injury. Interestingly, treatment with 4-PBA prevented burn-induced ER swelling and altered protein expression of ER stress markers and calcium release, attenuating calpain activation and skeletal muscle damage/wasting after severe burn injury. Atrogin-1 and LC3-II/LC3-I ratio were also increased in the burn group compared with the sham group, while MuRF-1 remained unchanged; 4-PBA decreased atrogin-1 in the burn group. Taken together, these findings suggested that severe burn injury induces ER stress, which in turns causes calpain activation. ER stress and subsequent activated calpain play a critical role in skeletal muscle damage/wasting in burned rats. PMID:29028830

Land surface temperature as potential indicator of burn severity in forest Mediterranean ecosystems

NASA Astrophysics Data System (ADS)

Quintano, C.; Fernández-Manso, A.; Calvo, L.; Marcos, E.; Valbuena, L.

2015-04-01

Forest fires are one of the most important causes of environmental alteration in Mediterranean countries. Discrimination of different degrees of burn severity is critical for improving management of fire-affected areas. This paper aims to evaluate the usefulness of land surface temperature (LST) as potential indicator of burn severity. We used a large convention-dominated wildfire, which occurred on 19-21 September, 2012 in Northwestern Spain. From this area, a 1-year series of six LST images were generated from Landsat 7 Enhanced Thematic Mapper (ETM+) data using a single channel algorithm. Further, the Composite Burn Index (CBI) was measured in 111 field plots to identify the burn severity level (low, moderate, and high). Evaluation of the potential relationship between post-fire LST and ground measured CBI was performed by both correlation analysis and regression models. Correlation coefficients were higher in the immediate post-fire LST images, but decreased during the fall of 2012 and increased again with a second maximum value in summer, 2013. A linear regression model between post-fire LST and CBI allowed us to represent spatially predicted CBI (R-squaredadj > 85%). After performing an analysis of variance (ANOVA) between post-fire LST and CBI, a Fisher's least significant difference test determined that two burn severity levels (low-moderate and high) could be statistically distinguished. The identification of such burn severity levels is sufficient and useful to forest managers. We conclude that summer post-fire LST from moderate resolution satellite data may be considered as a valuable indicator of burn severity for large fires in Mediterranean forest ecosytems.

Global analysis of the persistence of the spectral signal associated with burned areas

NASA Astrophysics Data System (ADS)

Melchiorre, A.; Boschetti, L.

2015-12-01

Systematic global burned area maps at coarse spatial resolution (350 m - 1 km) have been produced in the past two decades from several Earth Observation (EO) systems (including MODIS, Spot-VGT, AVHRR, MERIS), and have been extensively used in a variety of applications related to emissions estimation, fire ecology, and vegetation monitoring (Mouillot et al. 2014). There is however a strong need for moderate to high resolution (10-30 m) global burned area maps, in order to improve emission estimations, in particular on heterogeneous landscapes and for local scale air quality applications, for fire management and environmental restoration, and in support of carbon accounting (Hyer and Reid 2009; Mouillot et al. 2014; Randerson et al. 2012). Fires causes a non-permanent land cover change: the ash and charcoal left by the fire can be visible for a period ranging from a few weeks in savannas and grasslands ecosystems, to over a year in forest ecosystems (Roy et al. 2010). This poses a major challenge for designing a global burned area mapping system from moderate resolution (10-30 m) EO data, due to the low revisit time frequency of the satellites (Boschetti et al. 2015). As a consequence, a quantitative assessment of the permanence of the spectral signature of burned areas at global scale is a necessary step to assess the feasibility of global burned area mapping with moderate resolution sensors. This study presents a global analysis of the post-fire reflectance of burned areas, using the MODIS MCD45A1 global burned area product to identify the location and timing of burning, and the MO(Y)D09 global surface reflectance product to retrieve the time series of reflectance values after the fire. The result is a spatially explicit map of persistence of burned area signal, which is then summarized by landcover type, and by fire zone using the subcontinental regions defined by Giglio et al. (2006).

Evaluation of long term health-related quality of life in extensive burns: a 12-year experience in a burn center.

PubMed

Xie, Bing; Xiao, Shi-chu; Zhu, Shi-hui; Xia, Zhao-fan

2012-05-01

We sought to evaluate the long term health-related quality of life (HRQOL) in patients survived severely extensive burn and identify their clinical predicting factors correlated with HRQOL. A cross-sectional study was conducted in 20 patients survived more than 2 years with extensive burn involving ≥70% total body surface area (TBSA) between 1997 and 2009 in a burn center in Shanghai. Short Form-36 Medical Outcomes Survey (SF-36), Brief Version of Burn Specific Health Scale (BSHS-B) and Michigan Hand Outcome Questionnaire (MHQ) were used for the present evaluation. SF-36 scores were compared with a healthy Chinese population, and linear correlation analysis was performed to screen the clinical relating factors predicting physical and mental component summary (PCS and MCS) scores from SF-36. HRQOL scores from SF-36 were significantly lower in the domains of physical functioning, role limitations due to physical problems, pain, social functioning and role limitations due to emotional problems compared with population norms. Multiple linear regression analysis demonstrated that only return to work (RTW) predicted improved PCS. While age at injury, facial burns, skin grafting and length of hospital stay were correlated with MCS. Work, body image and heat sensitivity obtained the lowest BSHS-B scores in all 9 domains. Improvements of HRQOL could still be seen in BSHS-B scores in domains of simple abilities, hand function, work and affect even after a quite long interval between burns and testing. Hand function of extensive burn patients obtained relatively poor MHQ scores, especially in those without RTW. Patients with extensive burns have a poorer quality of life compared with that of general population. Relatively poor physical and psychological problems still exist even after a long period. Meanwhile, a trend of gradual improvements was noted. This information will aid clinicians in decision-making of comprehensive systematic regimens for long term rehabilitation and psychosocial treatment. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

A Burke-Schumann Analysis of Dual-Flame Structure Supported by a Burning Droplet

NASA Technical Reports Server (NTRS)

Nayagam, V.; Dietrich, D.; Williams, F. A.

2016-01-01

Droplet combustion experiments carried out onboard the International Space Station (ISS), using pure fuels and fuel mixtures, have shown that quasi-steady burning can be sustained by a non-traditional flame configuration, namely a "cool flame" burning in the "partial-burning" regime where both fuel and oxygen leak through the low-temperature controlled flame-sheet. Recent experiments involving large, bi-component fuel (n-decane and hexanol, 50/50 by volume) droplets at elevated pressures show that the visible, hot flame becomes extremely weak while the burning rate remains relatively high, suggesting the possibility of simultaneous presence of "cool" and "hot" flames of roughly equal importance. The radiant output from these bi-component droplets is relatively high and cannot be accounted for only by the presence of a visible hot-flame. In this analysis we explore the theoretical possibility of a dual-flame structure, where one flame lies close to the droplet surface called the "cool-flame," and other farther away from the droplet surface, termed the "hot-flame." A Burke-Schumann analysis of this dual-structure seems to indicate such flame structures are possible over a narrow range of initial conditions. Theoretical results can be compared against available experimental data for pure and bi-component fuel droplet combustion to test how realistic the model may be.

Management of acid burns: experience from Bangladesh.

PubMed

Das, Kishore Kumar; Olga, Loren; Peck, Michael; Morselli, Paolo G; Salek, A J M

2015-05-01

Acid burn injuries in Bangladesh primarily occur as a result of intentional attacks although there are incidences of accidental acid burns in industry, on the street, and at home. A total of 126 patients with acid burns, 95 from attacks and 31 from accidents, were studied from July 2004 to December 2012. A diagnosis of acid burn was made from history, physical examination and in some cases from chemical analysis of the patients' clothing. Alkali burns were excluded from the study. In the burn unit of Dhaka Medical College Hospital, we applied a slightly different protocol for management of acid burns, beginning with plain water irrigation of the wound, which effectively reduced burn depth and the requirement of surgical treatment. Application of hydrocolloid dressing for 48-72 h helped with the assessment of depth and the course of treatment. Early excision and grafting gives good results but resultant acid trickling creates a marble cake-like appearance of the wound separated by the vital skin. Excision with a scalpel and direct stitching of the wounds are often a good option. Observation of patients on follow-up revealed that wounds showed a tendency for hypertrophy. Application of pressure garments and other scar treatments were given in all cases unless the burn was highly superficial. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Long term repeated prescribed burning increases evenness in the basidiomycete laccase gene pool in forest soils.

PubMed

Artz, Rebekka R E; Reid, Eileen; Anderson, Ian C; Campbell, Colin D; Cairney, John W G

2009-03-01

Repeated prescribed burning alters the biologically labile fraction of nutrients and carbon of soil organic matter (SOM). Using a long-term (30 years) repeated burning experiment where burning has been carried out at a 2- or 4-year frequency, we analysed the effect of prescribed burning on gross potential C turnover rates and phenol oxidase activity in relation to shifts in SOM composition as observed using Fourier-transform infrared spectroscopy. In tandem, we assessed the genetic diversity of basidiomycete laccases. While the overall effect of burning was a decline in phenol oxidase activity, Shannon diversity and evenness of laccases was significantly higher in burned sites. Co-correspondence analysis of SOM composition and laccase operational taxonomic unit frequency data also suggested a strong correlation. While this correlation could indicate that the observed increase in laccase genetic diversity due to burning is due to increased resource diversity, a temporal replacement of the most abundant members of the assembly by an otherwise dormant pool of fungi cannot be excluded. As such, our results fit the intermediate disturbance hypothesis. Effects were stronger in plots burned in 2-year rotations, suggesting that the 4-year burn frequency may be a more sustainable practice to ensure the long-term stability of C cycling in such ecosystems.

Survival after burn in a sub-Saharan burn unit: challenges and opportunities.

PubMed

Tyson, Anna F; Boschini, Laura P; Kiser, Michelle M; Samuel, Jonathan C; Mjuweni, Steven N; Cairns, Bruce A; Charles, Anthony G

2013-12-01

Burns are among the most devastating of all injuries and a major global public health crisis, particularly in sub-Saharan Africa. In developed countries, aggressive management of burns continues to lower overall mortality and increase lethal total body surface area (TBSA) at which 50% of patients die (LA50). However, lack of resources and inadequate infrastructure significantly impede such improvements in developing countries. This study is a retrospective analysis of patients admitted to the burn center at Kamuzu Central Hospital in Lilongwe, Malawi between June 2011 and December 2012. We collected information including patient age, gender, date of admission, mechanism of injury, time to presentation to hospital, total body surface area (TBSA) burn, comorbidities, date and type of operative procedures, date of discharge, length of hospital stay, and survival. We then performed bivariate analysis and logistic regression to identify characteristics associated with increased mortality. A total of 454 patients were admitted during the study period with a median age of 4 years (range 0.5 months to 79 years). Of these patients, 53% were male. The overall mean TBSA was 18.5%, and average TBSA increased with age--17% for 0-18 year olds, 24% for 19-60 year olds, and 41% for patients over 60 years old. Scald and flame burns were the commonest mechanisms, 52% and 41% respectively, and flame burns were associated with higher mortality. Overall survival in this population was 82%; however survival reduced with increasing age categories (84% in patients 0-18 years old, 79% in patients 19-60 years old, and 36% in patients older than 60 years). TBSA remained the strongest predictor of mortality after adjusting for age and mechanism of burn. The LA50 for this population was 39% TBSA. Our data reiterate that burn in Malawi is largely a pediatric disease and that the high burn mortality and relatively low LA50 have modestly improved over the past two decades. The lack of financial resources, health care personnel, and necessary infrastructure will continue to pose a significant challenge in this developing nation. Efforts to increase burn education and prevention in addition to improvement of burn care delivery are imperative. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Survival after burn in a sub-Saharan burn unit: Challenges and opportunities

PubMed Central

Tyson, Anna F.; Boschini, Laura P.; Kiser, Michelle M.; Samuel, Jonathan C.; Mjuweni, Steven N.; Cairns, Bruce A.; Charles, Anthony G.

2013-01-01

Background Burns are among the most devastating of all injuries and a major global public health crisis, particularly in sub-Saharan Africa. In developed countries, aggressive management of burns continues to lower overall mortality and increase lethal total body surface area (TBSA) at which 50% of patients die (LA50). However, lack of resources and inadequate infrastructure significantly impede such improvements in developing countries. Methods This study is a retrospective analysis of patients admitted to the burn center at Kamuzu Central Hospital in Lilongwe, Malawi between June 2011 and December 2012. We collected information including patient age, gender, date of admission, mechanism of injury, time to presentation to hospital, total body surface area (TBSA) burn, comorbidities, date and type of operative procedures, date of discharge, length of hospital stay, and survival. We then performed bivariate analysis and logistic regression to identify characteristics associated with increased mortality. Results A total of 454 patients were admitted during the study period with a median age of 4 years (range 0.5 months to 79 years). Of these patients, 53% were male. The overall mean TBSA was 18.5%, and average TBSA increased with age—17% for 0–18 year olds, 24% for 19–60 year olds, and 41% for patients over 60 years old. Scald and flame burns were the commonest mechanisms, 52% and 41% respectively, and flame burns were associated with higher mortality. Overall survival in this population was 82%; however survival reduced with increasing age categories (84% in patients 0–18 years old, 79% in patients 19–60 years old, and 36% in patients older than 60 years). TBSA remained the strongest predictor of mortality after adjusting for age and mechanism of burn. The LA50 for this population was 39% TBSA. Discussion Our data reiterate that burn in Malawi is largely a pediatric disease and that the high burn mortality and relatively low LA50 have modestly improved over the past two decades. The lack of financial resources, health care personnel, and necessary infrastructure will continue to pose a significant challenge in this developing nation. Efforts to increase burn education and prevention in addition to improvement of burn care delivery are imperative. PMID:23768710

An eclipsing post common-envelope system consisting of a pulsating hot subdwarf B star and a brown dwarf companion

NASA Astrophysics Data System (ADS)

Schaffenroth, V.; Barlow, B. N.; Drechsel, H.; Dunlap, B. H.

2015-04-01

Hot subdwarf B stars (sdBs) are evolved, core helium-burning objects located on the extreme horizontal branch. Their formation history is still puzzling because the sdB progenitors must lose nearly all of their hydrogen envelope during the red-giant phase. About half of the known sdBs are in close binaries with periods from 1.2 h to a few days, which implies that they experienced a common-envelope phase. Eclipsing hot subdwarf binaries (also called HW Virginis systems) are rare but important objects for determining fundamental stellar parameters. Even more significant and uncommon are those binaries containing a pulsating sdB, since the mass can be determined independently by asteroseismology. Here we present a first analysis of the eclipsing hot subdwarf binary V2008-1753. The light curve shows a total eclipse, a prominent reflection effect, and low-amplitude pulsations with periods from 150 to 180 s. An analysis of the light- and radial velocity curves indicates a mass ratio close to q = 0.146, an radial velocity semi-amplitude of K = 54.6 km s-1, and an inclination of i = 86.8°. Combining these results with our spectroscopic determination of the surface gravity, log g = 5.83, the best-fitting model yields an sdB mass of 0.47 M⊙ and a companion mass of 69 MJup. Because the latter mass is below the hydrogen-burning limit, V2008-1753 represents the first HW Vir system that is known to consist of a pulsating sdB and a brown dwarf companion. Consequently, it holds strong potential for better constraining models of sdB binary evolution and asteroseismology.

Burnt area detection and hotspot analysis of wildfires in Margalla Hills National Park

NASA Astrophysics Data System (ADS)

Khalid, Noora; Ullah, Saleem

2016-07-01

Wildfires have been a growing source for the forest degradation and reduction in carbon sequestration which cause climate change and global warming. Thus, severely affect the ecosystem when not checked. Studies have revealed that land managements that do not use fire reduce the fire incidents by as much as 69 percent. This study focuses on mapping the areas burnt by forest fires owing to both natural and anthropogenic causes and identifying the fire prone areas in biodiversity spot of Islamabad, Margalla Hills National Park. The methodology employed based on using remotely sensed data with the integration of GIS techniques to estimate the area in hectares turned to ashes which ensued from forest fires during summers of 2008, 2010 and 2011 by applying Normalized Burn Ratio. Moreover hotspot analysis has also been used to pin point the locations with frequent fire incidents in the past using Global Positioning System (GPS) acquired coordinates from the fire surveys and official burned area statistics. The results revealed that wildfires destroyed some common regions in three years towards west which comprise of dense woodland comprising mainly Acacia Modesta, Dalbergia sissoo and Pinus longifolia. The calculated burnt area was 516 hectares, 122 hectares and 45 hectares for 2008, 2010 and 2011 respectively. Although a decline in burnt area has been observed owing to responsible management of authorities and development of fire pickets, still measures need to be taken to eradicate the core causes in charge of these fires and to promote reforestation. This study will allow policy makers and regulatory authorities to identify risk prone areas which will assist them in formulating a strategy to suppress fire incidents.

A concept for a fuel efficient flight planning aid for general aviation

NASA Technical Reports Server (NTRS)

Collins, B. P.; Haines, A. L.; Wales, C. J.

1982-01-01

A core equation for estimation of fuel burn from path profile data was developed. This equation was used as a necessary ingredient in a dynamic program to define a fuel efficient flight path. The resultant algorithm is oriented toward use by general aviation. The pilot provides a description of the desired ground track, standard aircraft parameters, and weather at selected waypoints. The algorithm then derives the fuel efficient altitudes and velocities at the waypoints.

Effect of piracetam and nimodipine on full-thickness skin burns in rabbits.

PubMed

Sari, Elif; Dincel, Gungor C

2016-08-01

The potential of several drugs for full-thickness skin burns has been investigated, but the treatment of such burns remains a challenge in plastic surgery. The present study was designed to determine the effect of systemic and topical administration of piracetam and nimodipine on full-thickness skin burn wound healing. A total of 36 New Zealand male rabbits were divided into six groups. Full-thickness skin burns were produced in all the groups, except the control group. Piracetam was administered systemically (piracetam-IV) and topically (piracetam-C) for 14 days, and nimodipine was administered systemically (nimodipine-IV) and topically (nimodipine-C) over the burn wounds for 14 days. The sham group underwent burn injury but was not administered any drug. After 21 days, gross examination and histopathological analysis were performed and the results were compared statistically. Nimodipine-C and nimodipine-IV had no effect on burn wound healing. However, both piracetam-IV and piracetam-C significantly enhanced the healing of the full-thickness skin burn wounds, although the latter was more effective, useful and practical in burn wound healing. The histopathological features of the wounds in the piracetam-C group were closer to those of the control group than those of the other groups. Piracetam-C rather than piracetam-IV may promote full-thickness burn wound healing in rabbits. © 2015 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Composition of breeding bird communities in Gulf Coast Chenier Plain marshes: Effects of winter burning

USGS Publications Warehouse

Gabrey, S.W.; Afton, A.D.

2004-01-01

Marsh managers along the Gulf Coast Chenier Plain frequently use winter burns to alter marsh vegetation and improve habitat quality for wintering waterfowl. However, effects of these burns on marsh avifauna are not well documented. We recorded abundances of breeding bird species and vegetation structure in burned and unburned control marshes during one breeding season before (1996) and two breeding seasons after (1997, 1998) experimental winter burns. We used non-metric multidimensional scaling analysis to assess the extent and direction of changes in bird community compositions of burned and unburned control marshes and to investigate the influence of vegetation structure on bird community composition. Overall, we found that Seaside Sparrows (Emberizidae: Ammodramus maritimus [Wilson]) and Red-winged Blackbirds and Boat-tailed Grackles (Icteridae: Agelaius phoeniceus [L.] and Quiscalus major Vieillot, respectively) comprised > 85% of observed birds. In burned marshes during the first breeding season following experimental burns (1997), icterid abundance increased while Seaside Sparrow abundance decreased relative to pre-burn (1996) conditions. This pattern was reversed during the second breeding season post-burn. No obvious patterns of change in avian abundance were detected in unburned control marshes over the 3-year period. Qualitative changes in breeding bird community composition were related to effects of winter burning on percent cover of dead vegetation and Spartina patens (Aiton) Muhl.

Nuclear Data Uncertainties for Typical LWR Fuel Assemblies and a Simple Reactor Core

NASA Astrophysics Data System (ADS)

Rochman, D.; Leray, O.; Hursin, M.; Ferroukhi, H.; Vasiliev, A.; Aures, A.; Bostelmann, F.; Zwermann, W.; Cabellos, O.; Diez, C. J.; Dyrda, J.; Garcia-Herranz, N.; Castro, E.; van der Marck, S.; Sjöstrand, H.; Hernandez, A.; Fleming, M.; Sublet, J.-Ch.; Fiorito, L.

2017-01-01

The impact of the current nuclear data library covariances such as in ENDF/B-VII.1, JEFF-3.2, JENDL-4.0, SCALE and TENDL, for relevant current reactors is presented in this work. The uncertainties due to nuclear data are calculated for existing PWR and BWR fuel assemblies (with burn-up up to 40 GWd/tHM, followed by 10 years of cooling time) and for a simplified PWR full core model (without burn-up) for quantities such as k∞, macroscopic cross sections, pin power or isotope inventory. In this work, the method of propagation of uncertainties is based on random sampling of nuclear data, either from covariance files or directly from basic parameters. Additionally, possible biases on calculated quantities are investigated such as the self-shielding treatment. Different calculation schemes are used, based on CASMO, SCALE, DRAGON, MCNP or FISPACT-II, thus simulating real-life assignments for technical-support organizations. The outcome of such a study is a comparison of uncertainties with two consequences. One: although this study is not expected to lead to similar results between the involved calculation schemes, it provides an insight on what can happen when calculating uncertainties and allows to give some perspectives on the range of validity on these uncertainties. Two: it allows to dress a picture of the state of the knowledge as of today, using existing nuclear data library covariances and current methods.

HE 0430-2457: a post-merger extremely low-mass pre-white dwarf in a wide binary posing as an extreme horizontal branch star

NASA Astrophysics Data System (ADS)

Vos, Joris; Zorotovic, Monica; Vučković, Maja; Schreiber, Matthias R.; Østensen, Roy

2018-06-01

We report the discovery of HE 0430-2457, the first extremely low-mass pre-white dwarf (ELM pre-WD) in a long period binary (P = 771 ± 3 d). The spectroscopic parameters of the primary are determined to be Teff = 26 200 ± 1500 K and log g = 5.40 ± 0.35, placing it in the region occupied by core He-burning hot subdwarf B stars. By comparing the spectroscopic parameters of the K-type companion to stellar models, and using the mass ratio, the mass of the hot primary is determined to be 0.23 M⊙. Given that this is too low for core He-burning, the primary in HE 0430-2457 is not an extreme horizontal branch (EHB) star but a pre-WD of the ELM type. As the lifetime of ELM pre-WDs in this region of the Hertzsprung Russel diagram populated by EHBs is thought to be very short, they are not considered to be part of the observed EHBs. However, the discovery of this system indicates that the percentage of ELM pre-WDs in the observed EHB population might be higher than previously thought. Binary evolution models indicate that HE 0430-2457 is likely formed by a merger of the inner binary in a hierarchical triple system.

Pre-supernova outbursts via wave heating in massive stars - II. Hydrogen-poor stars

NASA Astrophysics Data System (ADS)

Fuller, Jim; Ro, Stephen

2018-05-01

Pre-supernova (SN) outbursts from massive stars may be driven by hydrodynamical wave energy emerging from the core of the progenitor star during late nuclear-burning phases. Here, we examine the effects of wave heating in stars containing little or no hydrogen, i.e. progenitors of Type IIb/Ib SNe. Because there is no massive hydrogen envelope, wave energy is thermalized near the stellar surface where the overlying atmospheric mass is small but the optical depth is large. Wave energy can thus unbind this material, driving an optically thick, super-Eddington wind. Using 1D hydrodynamic MESA simulations of ˜5 M⊙ He stars, we find that wave heating can drive pre-SN outbursts composed of a dense wind whose mass-loss rate can exceed ˜0.1 M⊙ yr-1. The wind terminal velocities are a few 100 km s-1, and outburst luminosities can reach ˜106 L⊙. Wave-driven outbursts may be linked with observed or inferred pre-SN outbursts of Type Ibn/transitional/transformational SNe, and pre-SN wave-driven mass loss is a good candidate to produce these types of SNe. However, we also show that non-linear wave breaking in the core of the star may prevent such outbursts in stars with thick convective helium-burning shells. Hence, only a limited subset of SN progenitors is likely to experience wave-driven pre-SN outbursts.

Electroacupuncture improves burn-induced impairment in gastric motility mediated via the vagal mechanism in rats.

PubMed

Song, J; Yin, J; Sallam, H S; Bai, T; Chen, Y; Chen, J D Z

2013-10-01

Delayed gastric emptying (GE) is common in patients with severe burns. This study was designed to investigate effects and mechanisms of electroacupuncture (EA) on gastric motility in rats with burns. Male rats (intact and vagotomized) were implanted with gastric electrodes, chest and abdominal wall electrodes for investigating the effects of EA at ST-36 (stomach-36 or Zusanli) on GE, gastric slow waves, autonomic functions, and plasma interleukin 6 (IL-6) 6 and 24 h post severe burns. (i) Burn delayed GE (P < 0.001). Electroacupuncture improved GE 6 and 24 h post burn (P < 0.001). Vagotomy blocked the EA effect on GE. (ii) Electroacupuncture improved burn-induced gastric dysrhythmia. The percentage of normal slow waves was increased with EA 6 and 24 h post burn (P = 0.02). (iii) Electroacupuncture increased vagal activity assessed by the spectral analysis of heart rate variability (HRV). The high-frequency component reflecting vagal component was increased with EA 6 (P = 0.004) and 24 h post burn (P = 0.03, vs sham-EA). (iv) Electroacupuncture attenuated burn-induced increase in plasma IL-6 at both 6 (P = 0.03) and 24 h post burn (P = 0.003). Electroacupuncture at ST-36 improves gastric dysrhythmia and accelerates GE in rats with burns. The improvement seems to be mediated via the vagal pathway involving the inflammatory cytokine IL-6. © 2013 John Wiley & Sons Ltd.

Effect of blood transfusion on outcome after major burn injury: a multicenter study.

PubMed

Palmieri, Tina L; Caruso, Daniel M; Foster, Kevin N; Cairns, Bruce A; Peck, Michael D; Gamelli, Richard L; Mozingo, David W; Kagan, Richard J; Wahl, Wendy; Kemalyan, Nathan A; Fish, Joel S; Gomez, Manuel; Sheridan, Robert L; Faucher, Lee D; Latenser, Barbara A; Gibran, Nicole S; Klein, Robert L; Solem, Lynn D; Saffle, Jeffrey R; Morris, Stephen E; Jeng, James C; Voigt, David; Howard, Pamela A; Molitor, Fred; Greenhalgh, David G

2006-06-01

To delineate blood transfusion practices and outcomes in patients with major burn injury. Patients with major burn injury frequently require multiple blood transfusions; however, the effect of blood transfusion after major burn injury has had limited study. Multicenter retrospective cohort analysis. Regional burn centers throughout the United States and Canada. Patients admitted to a participating burn center from January 1 through December 31, 2002, with acute burn injuries of >or=20% total body surface area. Outcome measurements included mortality, number of infections, length of stay, units of blood transfused in and out of the operating room, number of operations, and anticoagulant use. A total of 21 burn centers contributed data on 666 patients; 79% of patients survived and received a mean of 14 units of packed red blood cells during their hospitalization. Mortality was related to patient age, total body surface area burn, inhalation injury, number of units of blood transfused outside the operating room, and total number of transfusions. The number of infections per patient increased with each unit of blood transfused (odds ratio, 1.13; p<.001). Patients on anticoagulation during hospitalization received more blood than patients not on anticoagulation (16.3+/-1.5 vs. 12.3+/-1.5, p<.001). The number of transfusions received was associated with mortality and infectious episodes in patients with major burns even after factoring for indices of burn severity. The utilization of blood products in the treatment of major burn injury should be reserved for patients with a demonstrated physiologic need.

Expression and activity levels of chymase in mast cells of burn wound tissues increase during the healing process in a hamster model.

PubMed

Dong, Xianglin; Xu, Tao; Ma, Shaolin; Wen, Hao

2015-06-01

The present study aimed to investigate the changes in the expression levels and activity of mast cell chymase in the process of burn wound healing in a hamster model of deep second-degree burn. The hamster model was established by exposing a ~3 cm diameter area of bare skin to hot water (75°C) for 0, 6, 8, 10 or 12 sec. Tissue specimens were collected 24 h after burning and histological analysis revealed that hot water contact for 12 sec was required to produce a deep second-degree burn. Quantitative polymerase chain reaction and a radioimmunoassay were used to the determine changes in chymase mRNA expression levels and activity. The mRNA expression levels and activity of chymase were increased in the burn wound tissues when compared with the normal skin. However, no statistically significant differences were observed in mast cell chymase activity amongst the various post-burn stages. Chymase mRNA expression levels peaked at day 1 post-burn, subsequently decreasing at days 3 and 7 post-burn and finally increasing again at day 14 post-burn. In summary, a hamster model of deep second-degree burn can be created by bringing the skin into contact with water at 75°C for 12 sec. Furthermore, the mRNA expression levels and activity of chymase in the burn wound tissues increased when compared with those in normal skin tissues.

Expression and activity levels of chymase in mast cells of burn wound tissues increase during the healing process in a hamster model

PubMed Central

DONG, XIANGLIN; XU, TAO; MA, SHAOLIN; WEN, HAO

2015-01-01

The present study aimed to investigate the changes in the expression levels and activity of mast cell chymase in the process of burn wound healing in a hamster model of deep second-degree burn. The hamster model was established by exposing a ~3 cm diameter area of bare skin to hot water (75°C) for 0, 6, 8, 10 or 12 sec. Tissue specimens were collected 24 h after burning and histological analysis revealed that hot water contact for 12 sec was required to produce a deep second-degree burn. Quantitative polymerase chain reaction and a radioimmunoassay were used to the determine changes in chymase mRNA expression levels and activity. The mRNA expression levels and activity of chymase were increased in the burn wound tissues when compared with the normal skin. However, no statistically significant differences were observed in mast cell chymase activity amongst the various post-burn stages. Chymase mRNA expression levels peaked at day 1 post-burn, subsequently decreasing at days 3 and 7 post-burn and finally increasing again at day 14 post-burn. In summary, a hamster model of deep second-degree burn can be created by bringing the skin into contact with water at 75°C for 12 sec. Furthermore, the mRNA expression levels and activity of chymase in the burn wound tissues increased when compared with those in normal skin tissues. PMID:26136958

X-Ray Fluorescence to Estimate the Maximum Temperature Reached at Soil Surface during Experimental Slash-and-Burn Fires.

PubMed

Melquiades, Fábio L; Thomaz, Edivaldo L

2016-05-01

An important aspect for the evaluation of fire effects in slash-and-burn agricultural system, as well as in wildfire, is the soil burn severity. The objective of this study is to estimate the maximum temperature reached in real soil burn events using energy dispersive X-ray fluorescence (EDXRF) as an analytical tool, combined with partial least square (PLS) regression. Muffle-heated soil samples were used for PLS regression model calibration and two real slash-and-burn soils were tested as external samples in the model. It was possible to associate EDXRF spectra alterations to the maximum temperature reached in the heat affected soils with about 17% relative standard deviation. The results are promising since the analysis is fast, nondestructive, and conducted after the burn event, although local calibration for each type of burned soil is necessary. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Benefit-cost analysis of moist exposed burn ointment.

PubMed

Atiyeh, Bishara S; Dham, Ruwayda; Kadry, Mohammaed; Abdallah, Abdel Fattah; Al-Oteify, Mahmoud; Fathi, Osman; Samir, Ahmed

2002-11-01

Burn injury is one of the most devastating injuries that may affect a patient. Even in economically deprived areas, burn care is largely driven by relatively plentiful resources equating quality of care with generous monitoring and clinical attention with little concern to management cost. Burn care costs have been the subject of very few investigations and are among the least studied by health services researchers. Nevertheless, it can be stated that local care of burn wounds accounts for a large proportion of the cost per day for treating patients. As economic times are changing and as market penetration of managed care contracts and stiff competition in the health care industry gains momentum, ways to reduce expenditures without adversely affecting the quality of care have become of primary importance. We report a randomized prospective comparative study analyzing the benefit-cost value of moist exposed burn ointment (MEBO) application, an exposed method for burn wound care without the need for a secondary covering dressing, as compared to conventional closed methods.

Fatal burns in Manipal area: a 10 year study.

PubMed

Kumar, Virendra; Mohanty, Manoj Kumar; Kanth, Sarita

2007-01-01

The purpose of this study was to record and evaluate the causes and the magnitude of the fatal burn injuries retrospectively. An analysis of autopsy records revealed 19.4% cases of burn injuries amongst the total autopsies done over 10years period (1993-2002) in the mortuary of the department of Forensic Medicine of Kasturba medical College, Manipal. The majority of deaths (78.5%) occurred between 11 and 40years of age group with preponderance of females (74.8%). The flame burns were seen in 94.1% of the victims followed by scalds and electrical burns in 2.8% and 2.5% cases, respectively. The majority of burn incidents were accidental (75.8%) in nature followed by suicidal (11.5%) and homicidal (3.1%) deaths. The percentage of burn (TBSA) over 40% were observed in most of the cases (92.5%). The majority of deaths occurred within a week (69.87%) and most the victims died because of septicemia (50.9%).

Does nurses'perceived burn prevention knowledge and ability to teach burn prevention correlate with their actual burn prevention knowledge?

PubMed

Lehna, Carlee; Myers, John

2010-01-01

The purpose of this study was to explore the relationship among nurses'perceived burn prevention knowledge, their perceived ability to teach about burn prevention, and their actual burn prevention knowledge and to test if their actual burn knowledge could be predicted by these perceived measures. A two-page, anonymous survey that included a 10-item burn prevention knowledge test and an assessment of nurses'perceived knowledge of burn prevention and their perceived ability to teach burn prevention was administered to 313 nurses. Actual burn prevention knowledge was determined and the correlation among actual burn prevention knowledge, perceived knowledge, and perceived ability to teach was determined. Differences in these outcome variables based on specialty area were tested using analysis of variance techniques. Generalized linear modeling techniques were used to investigate which variables significantly predict a nurse's actual burn prevention knowledge. Test for interaction effects were performed, and significance was set at .05. Responding nurses (N = 265) described practicing in a variety of settings, such as pediatric settings (40.2%, n = 105), emergency departments (25.4%, n = 86), medical/surgical settings (8.4%, n = 22), and one pediatric burn setting (4.1%, n = 14), with all specialty areas as having similar actual burn prevention knowledge (P = .052). Seventy-seven percent of the nurses said they never taught about burn prevention (n = 177). Perceived knowledge and actual knowledge (r = .124, P = .046) as well as perceived knowledge and perceived ability were correlated (r = .799, P < .001). Significant predictors of actual knowledge were years in practice (beta = -0.063, P = .034), years in current area (beta = 0.072, P = .003), perceived knowledge (beta = 0.109, P = .042), and perceived ability (beta = 0.137, P = .019). All nurses, regardless of specialty area, have poor burn prevention knowledge, which is correlated with their perceived lack of knowledge of burn prevention. In addition, nurses'perceived burn knowledge and ability predicts their actual burn knowledge. This is a fruitful area that merits further research and exploration.

Computational study of single-expansion-ramp nozzles with external burning

NASA Astrophysics Data System (ADS)

Yungster, Shaye; Trefny, Charles J.

1992-04-01

A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

Structure analysis and size distribution of particulate matter from candles and kerosene combustion in burning chamber

NASA Astrophysics Data System (ADS)

Baitimirova, M.; Osite, A.; Katkevics, J.; Viksna, A.

2012-08-01

Burning of candles generates particulate matter of fine dimensions that produces poor indoor air quality, so it may cause harmful impact on human health. In this study solid aerosol particles of burning of candles of different composition and kerosene combustion were collected in a closed laboratory system. Present work describes particulate matter collection for structure analysis and the relationship between source and size distribution of particulate matter. The formation mechanism of particulate matter and their tendency to agglomerate also are described. Particles obtained from kerosene combustion have normal size distribution. Whereas, particles generated from the burning of stearin candles have distribution shifted towards finer particle size range. If an additive of stearin to paraffin candle is used, particle size distribution is also observed in range of towards finer particles. A tendency to form agglomerates in a short time is observed in case of particles obtained from kerosene combustion, while in case of particles obtained from burning of candles of different composition such a tendency is not observed. Particles from candles and kerosene combustion are Aitken and accumulation mode particles

Computational study of single-expansion-ramp nozzles with external burning

NASA Technical Reports Server (NTRS)

Yungster, Shaye; Trefny, Charles J.

1992-01-01

A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

Children with burns referred for child abuse evaluation: Burn characteristics and co-existent injuries.

PubMed

Pawlik, Marie-Christin; Kemp, Alison; Maguire, Sabine; Nuttall, Diane; Feldman, Kenneth W; Lindberg, Daniel M

2016-05-01

Intentional burns represent a serious form of physical abuse that must be identified to protect children from further harm. This study is a retrospectively planned secondary analysis of the Examining Siblings To Recognize Abuse (ExSTRA) network data. Our objective was to describe the characteristics of burns injuries in children referred to Child Abuse Pediatricians (CAPs) in relation to the perceived likelihood of abuse. We furthermore compare the extent of diagnostic investigations undertaken in children referred to CAPs for burn injuries with those referred for other reasons. Within this dataset, 7% (215/2890) of children had burns. Children with burns were older than children with other injuries (median age 20 months vs. 10 months). Physical abuse was perceived as likely in 40.9% (88) and unlikely in 59.1% (127). Scalds accounted for 52.6% (113) and contact burns for 27.6% (60). Several characteristics of the history and burn injury were associated with a significantly higher perceived likelihood of abuse, including children with reported inflicted injury, absent or inadequate explanation, hot water as agent, immersion scald, a bilateral/symmetric burn pattern, total body surface area ≥10%, full thickness burns, and co-existent injuries. The rates of diagnostic testing were significantly lower in children with burns than other injuries, yet the yield of skeletal survey and hepatic transaminases testing were comparable between the two groups. This would imply that children referred to CAPs for burns warrant the same level of comprehensive investigations as those referred for other reasons. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Protective effect of betaine against burn-induced pulmonary injury in rats.

PubMed

Şehirli, Ahmet Özer; Satılmış, Burcu; Tetik, Şermin; Çetinel, Şule; Yeğen, Berrak; Aykaç, Aslı; Şener, Göksel

2016-09-01

This study was designed to determine possible protective effect of betaine treatment against oxidative injury in pulmonary tissue induced with thermal trauma. Under ether anesthesia, shaved dorsum of Wistar albino rats was exposed to a 90°C water bath for 10 seconds to induce burn injury. Betaine was administered orally (250 mg/kg) for a period of 21 days before burn injury, and single dose of betaine was administered after thermal injury. Control group rats were exposed to 25°C water bath for 10 seconds. Upon conclusion of experiment, rats were decapitated and blood was collected for analysis of pro-inflammatory cytokines and lactate dehydrogenase (LDH) activity. Lung tissue samples were taken to determine malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO), and Na+/K+-ATPase activity, in addition to histological analysis. Burn injury caused significant increase in both cytokine levels and LDH activity. In lung samples, raised MDA levels, MPO activity, and reduced GSH levels and Na+/K+-ATPase activity were found due to burn injury. Treatment of rats with betaine significantly restored GSH level and Na+/K+-ATPase activity, and decreased MDA level and MPO activity. According to the findings of the present study, betaine significantly diminishes burn-induced damage in tissue.

Burn Delay Analysis of the Lunar Orbit Insertion for Korea Pathfinder Lunar Orbiter

NASA Astrophysics Data System (ADS)

Bae, Jonghee; Song, Young-Joo; Kim, Young-Rok; Kim, Bangyeop

2017-12-01

The first Korea lunar orbiter, Korea Pathfinder Lunar Orbiter (KPLO), has been in development since 2016. After launch, the KPLO will execute several maneuvers to enter into the lunar mission orbit, and will then perform lunar science missions for one year. Among these maneuvers, the lunar orbit insertion (LOI) is the most critical maneuver because the KPLO will experience an extreme velocity change in the presence of the Moon’s gravitational pull. However, the lunar orbiter may have a delayed LOI burn during operation due to hardware limitations and telemetry delays. This delayed burn could occur in different captured lunar orbits; in the worst case, the KPLO could fly away from the Moon. Therefore, in this study, the burn delay for the first LOI maneuver is analyzed to successfully enter the desired lunar orbit. Numerical simulations are performed to evaluate the difference between the desired and delayed lunar orbits due to a burn delay in the LOI maneuver. Based on this analysis, critical factors in the LOI maneuver, the periselene altitude and orbit period, are significantly changed and an additional delta-V in the second LOI maneuver is required as the delay burn interval increases to 10 min from the planned maneuver epoch.

The measured effect magnitude of co-morbidities on burn injury mortality.

PubMed

Knowlin, Laquanda; Stanford, Lindsay; Moore, Danier; Cairns, Bruce; Charles, Anthony

2016-11-01

The ability to better prognosticate burn injury outcome is challenging and historically, most center use the Baux or revised Baux score to help prognosticate burn outcome, however, the weighted contribution of comorbidity on burn mortality has traditionally not been accounted for nor adequately studied. We therefore sought to determine the effect of comorbidities, using the Charlson comorbidity index (CCI) on burn mortality. The purpose of this study was to determine the effect of comorbidities on burn injury mortality as determined by the LA50 (lethal TBSA burn at which 50% of the cohort will succumb from the burn injury) in a retrospective analysis of patients admitted to a regional burn center from 2002 to 2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA (total body surface area), length of hospital stay, and pre-existing comorbidities. Bivariate analysis was performed and logistic regression modeling using significant variables was utilized to estimate odds of death. 7640 patients were included in this study. Overall survival rate was 96%. 40% of our burn cohort had at least one comorbidity. There was a linear increase in the likelihood of death with an increase in CCI. The logistic regression model for mortality outcomes identified four statistically significant variables: age, TBSA, inhalational injury and the presence of comorbidities (OR=1.59 for each 1 point increase in CCI; 95% CI 1.44-1.77). The unadjusted LA50 was 53% for the entire cohort. Partial adjustment multivariate regression controlling for burn mechanism and inhalation injury only, produced a slight reduction in LA50 for the 0-18 and 19-64 age categories to 76% and 48% TBSA, respectively, but a significant decrease occurred in the ≥65 years age group with a reduced LA50 to 20% TBSA (p<0.001). After full adjustment for all significant covariates, including comorbidities, the independent magnitude of effect of comorbidities on the LA50 was evident in the <65 cohort. The full adjustment showed a LA50 decreased to 61% and 43% TBSA, respectively in the 0-18 and >18-65 age groups respectively (p<0.001), however, in the >65 years age cohort there was no change in the LA50. Preexisting comorbidities have a significant effect on burn injury mortality in all age groups, particularly the younger burn population. The measured effect of comorbidities in the >65 yr age cohort was mitigated by the co-linearity between age and comorbidities. The inclusion of CCI is imperative so as to better prognosticate burn outcome and help guide expectations and resource utilization, particularly in the younger burn cohort. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

The Measured Effect Magnitude of Co-Morbidities on Burn injury Mortality

PubMed Central

Knowlin, Laquanda; Stanford, Lindsay; Moore, Danier; Cairns, Bruce; Charles, Anthony

2016-01-01

Introduction The ability to better prognosticate burn injury outcome is challenging and historically, most center use the Baux or revised Baux score to help prognosticate burn outcome, however, the weighted contribution of comorbidity on burn mortality has traditionally not been accounted for nor adequately studied. We therefore sought to determine the effect of comorbidities, using the Charlson comorbidity index (CCI) on burn mortality. Methods The purpose of this study was to determine the effect of comorbidities on burn injury mortality as determined by the LA50 (lethal TBSA burn at which 50% of the cohort will succumb from the burn injury) in a retrospective analysis of patients admitted to a regional burn center from 2002–2012. Independent variables analyzed included basic demographics, burn mechanism, presence of inhalation injury, TBSA (total body surface area), length of hospital stay, and pre-existing comorbidities. Bivariate analysis was performed and logistic regression modeling using significant variables was utilized to estimate odds of death. Results 7640 patients were included in this study. Overall survival rate was 96%. 40% of our burn cohort had at least one comorbidity. There was a linear increase in the likelihood of death with an increase in CCI. The logistic regression model for mortality outcomes identified four statistically significant variables: age, TBSA, inhalational injury and the presence of comorbidities (OR = 1.59 for each 1 point increase in CCI; 95% CI 1.44–1.77). The unadjusted LA50 was 53% for the entire cohort. Partial adjustment multivariate regression controlling for burn mechanism and inhalation injury only, produced a slight reduction in LA50 for the 0–18 and 19–64 age categories to 76% and 48%, respectively, but a significant decrease occurred in the ≥ 65 years age group with a reduced LA50 to 20% (p<0.001). After full adjustment for all significant covariates, including comorbidities, the independent magnitude of effect of comorbidities on the LA50 was evident in the <65 cohort. The full adjustment showed a LA50 decreased by 15 and 5%, respectively in the 0–18 and >18–65 age groups respectively (p<0.001), however, in the >65 years age cohort there was no change in the LA50. Conclusion Preexisting comorbidities have a significant effect on burn injury mortality in all age groups, particularly the younger burn population. The measured effect of comorbidities in the >65yr age cohort was mitigated by the co-linearity between age and comorbidities. The inclusion of CCI is imperative so as to better prognosticate burn outcome and help guide expectations and resource utilization, particularly in the younger burn cohort.. PMID:27593340

Effect of Permeability of Tipping Paper on Cigarette Burning Temperature and the Property of Mainstream Smoke

NASA Astrophysics Data System (ADS)

Yao, Zhen-Yu; Shen, Yan; Huang, Hai-Qun; Xu, Ji-Cang

2016-05-01

Cigarette smoke analysis of tipping paper with different permeability was carried out. The infrared thermal imager was used to measure burning temperature of cigarette with different permeability tipping paper. The results indicated that with the increase of tipping paper permeability, Tar, CO and nicotine in cigarette mainstream were significantly linear decreased, puff count was increased. Tipping paper permeability had a great influence on cigarette burning temperature. With the increase of tipping paper permeability, the third puff burning temperature and the average peak temperature values were dropped obviously, but the changes of smoldering temperature were not obvious. In addition, smoldering average temperature was significantly lower than the third puff burning temperature and peak temperature.

Hyperbolic Rendezvous at Mars: Risk Assessments and Mitigation Strategies

NASA Technical Reports Server (NTRS)

Jedrey, Ricky; Landau, Damon; Whitley, Ryan

2015-01-01

Given the current interest in the use of flyby trajectories for human Mars exploration, a key requirement is the capability to execute hyperbolic rendezvous. Hyperbolic rendezvous is used to transport crew from a Mars centered orbit, to a transiting Earth bound habitat that does a flyby. Representative cases are taken from future potential missions of this type, and a thorough sensitivity analysis of the hyperbolic rendezvous phase is performed. This includes early engine cutoff, missed burn times, and burn misalignment. A finite burn engine model is applied that assumes the hyperbolic rendezvous phase is done with at least two burns.

Kinetic turbulence simulations at extreme scale on leadership-class systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bei; Ethier, Stephane; Tang, William

2013-01-01

Reliable predictive simulation capability addressing confinement properties in magnetically confined fusion plasmas is critically-important for ITER, a 20 billion dollar international burning plasma device under construction in France. The complex study of kinetic turbulence, which can severely limit the energy confinement and impact the economic viability of fusion systems, requires simulations at extreme scale for such an unprecedented device size. Our newly optimized, global, ab initio particle-in-cell code solving the nonlinear equations underlying gyrokinetic theory achieves excellent performance with respect to "time to solution" at the full capacity of the IBM Blue Gene/Q on 786,432 cores of Mira at ALCFmore » and recently of the 1,572,864 cores of Sequoia at LLNL. Recent multithreading and domain decomposition optimizations in the new GTC-P code represent critically important software advances for modern, low memory per core systems by enabling routine simulations at unprecedented size (130 million grid points ITER-scale) and resolution (65 billion particles).« less

The Chornobyl accident revisited, part II: The state of the nuclear fuel located within the Chornobyl Sarcophagus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borovol, A.A.; Sich, A.R.

1995-10-01

Approximately 135 tonnes of the 190.3-tonne initial core fuel load ({approx}71%) at Chornobyl Unit 4 melted and flowed into the lower regions of the reactor building to form various kinds of the now-solidified lava-like fuel-containing materials (LFCMs) or corium. The results of radiochemical analyses reveal that only 5% of the LFCM inventory of Ru-106 remains, whereas, surprisingly, 35% of the LFCM inventory of Cs-137 remains. Moreover, the results of these analyses support the fact that little if any of the 5020 tonnes of various materials (dropped from helicopters during the active phase of the accident in an attempt to smothermore » the burning graphite) ever made it into the core shaft, where the bulk of the core was located. The results appear to support earlier Western source-term estimates that significantly more volatile radionuclides may have been released as a result of the accident.« less

The Chornobyl accident revisited, Part II: The state of the nuclear fuel located within the Chornobyl sarcophagus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borovoi, A.A.; Sich, A.R.

1995-01-01

Approximately 135 tonnes of the 190.3-tonne initial core fuel load ({approx}71%) at Chernobyl Unit 4 melted and flowed into the lower regions of the reactor building to form various kinds of the now-solidified lava-like fuel-containing materials (LFCMs) or corium. The results of radiochemical analyses reveal that only 5% of the LFCM inventory of Ru-106 remains. whereas, surprisingly, 35% of the LFCM inventory of Cs-137 remains. Moreover, the results of these analyses support the fact that little if any of the 5020 tonnes of various materials (dropped from helicopters during the active phase of the accident in an attempt to smothermore » the burning graphite) ever made it into the core shaft, where the bulk of the core was located. The results appear to support earlier Western source-term estimates that significantly more volatile radionuclides may have been released as a result of the accident. 37 refs., 13 figs., 7 tabs.« less

The ultraviolet-bright stars of Omega Centauri, M3, and M13

NASA Technical Reports Server (NTRS)

Landsman, Wayne B.; O'Connell, Robert W.; Whitney, Jonathan H.; Bohlin, Ralph C.; Hill, Robert S.; Maran, Stephen P.; Parise, Ronald A.; Roberts, Morton S.; Smith, Andrew A.; Stecher, Theodore P.

1992-01-01

Two new UV-bright stars detected within 2 arcmin of the center of Omega Cen are spectroscopically investigated with the short-wavelength spectrograph of the IUE. The IUE spectra of the UV-bright stars UIT-1 and UIT-2 in the core of Omega Cen superficially resemble those of Population I mid-B stars. The absorption lines of the core UV-bright stars are significantly weaker than in Population I stars, consistent with their membership in the cluster. Synthetic spectra calculated from low-metallicity Kurucz model stellar atmospheres are compared with the spectra. These objects are insufficiently luminous to be classical hydrogen-burning post-AGB stars. They may be evolved hot horizontal branch stars which have been brightened by more than 3 mag since leaving the zero-age horizontal branch. It is inferred from the spectra and luminosity of the core UV-bright stars that similar objects could provide the source of the UV light in elliptical galaxies.

Double-gap Alfvén eigenmodes: revisiting eigenmode interaction with the alfvén continuum.

PubMed

Gorelenkov, N N

2005-12-31

A new type of global shear Alfvén eigenmode is found in tokamak plasmas where the mode localization is in the region intersecting the Alfvén continuum. The eigenmode is formed by the coupling of two solutions from two adjacent gaps (akin to potential wells) in the shear Alfvén continuum. For tokamak plasmas with reversed magnetic shear, it is shown that the toroidicity-induced solution tunnels through the continuum to match the ellipticity-induced Alfvén eigenmode so that the resulting solution is continuous at the point of resonance with the continuum. The existence of these double-gap Alfvén eigenmodes allows for potentially new ways of coupling edge fields to the plasma core in conditions where the core region is conventionally considered inaccessible. Implications include new approaches to heating and current drive in fusion plasmas as well as its possible use as a core diagnostic in burning plasmas.

40 CFR 63.7550 - What reports must I submit and when?

Code of Federal Regulations, 2011 CFR

2011-07-01

... tests for affected sources subject to an emission limit, a summary of any fuel analyses associated with... analysis). If you burned a new type of fuel and are subject to a mercury emission limit, you must submit... through fuel analysis). (7) If you wish to burn a new type of fuel in an affected source subject to an...

Evaluating the Socioeconomic and Cultural Factors Associated with Pediatric Burn Injuries in Maputo, Mozambique

PubMed Central

Karan, Abraar; Amado, Vanda; Vitorino, Pio; Kulber, David; Taela, Atanasio; DeUgarte, Daniel

2015-01-01

Background Pediatric burn injuries are one of the leading causes of preventable morbidity and mortality in Sub-Saharan Africa. Research on the complex system of social, economic and cultural factors contributing to burn injuries in this setting is much needed. Methods We conducted a prospective questionnaire-based analysis of pediatric burn patients presenting to the Hospital Central de Maputo. A total of 39 patients were included in the study. Interviews were conducted with the children’s caretakers by two trained medical students at the Eduardo Mondlane Medical School in Maputo with the aid of local nursing staff. Results Most burns occurred from scald wounds (26/39) particularly from bathwater, followed by fire burns (11/39). Burns occurred more frequently in the afternoon (16/39) and evening (16/39). Over one quarter of burns (9/33) occurred in the absence of a caretaker. One third (12/36) of participants attempted to treat the burn at home prior to bringing the child in to the hospital, and roughly two-thirds (24/37) reported using traditional remedies for burn care. The average household had just 2 rooms for an average of 5 family members. Most burns were grade II (25/37). Conclusions Prevention efforts in this setting are much needed and can be implemented taking complex cultural and social factors into account. Education regarding regulation of water temperature for baths is important, given the prevalence of scald burns. Moreover, the introduction of low-cost, safer cooking technology can help mitigate inhalation injury and reduce fire burns. Additionally, burn care systems must be integrated with local traditional medical interventions to respect local cultural medicinal practices. PMID:26280740

Investigation of fluids as filling of a biomimetic infrared sensor based on the infrared receptors of pyrophilous insects

NASA Astrophysics Data System (ADS)

Kahl, T.; Li, N.; Schmitz, H.; Bousack, H.

2012-04-01

The beetle Melanophila acuminata is highly dependent on forest fires. The burned wood serves as food for the larvae and the adults copulate on the burned areas to put their eggs in the freshly burned trees. To be able to detect forest fires from great distances the beetle developed a highly sensitive infrared receptor which works according to a photomechanical principle. The beetle has two pit organs, one on each lateral side, of which each houses around 70 dome shaped infrared receptors. These IR-receptors consist of a hard outer cuticular shell and an inner microfluidic core. When IR-radiation is absorbed, the pressure in the core increases due to the thermal expansion. This results in a deflection of a dendritic tip of a mechanosensitiv neuron which generates the signal. This biological principle was transferred into a new kind of un-cooled technical infrared receptor. To demonstrate the functional principle and the feasibility of this IR-sensor a macroscopic demonstrator sensor was build. It consisted of an inner fluid filled cavity (pressure chamber), an IR-transmissive window and a membrane. The deflection of the membrane due to the absorbed IR-energy was measured by a sensitive commercial capacitive sensor. In the experiments ethanol with added black ink, a mix of ethanol and glucose with additional absorber, air with additional absorber and water were used as fillings of the cavity and compared against each other. In order to get insights into the physics of the results of the experiments accompanying simulations using FEM methods and analytical calculations have been performed. The results showed that ethanol and air as fillings of the cavity caused the largest deflection of the membrane. Furthermore it turned out that the thermal expansion of the sensor housing material has an important influence. The comparison of the measured deflection with calculated deflections showed a good concordance.

Epidemiology of burns due to domestic flammable agents.

PubMed

Pegg, S P; Beecham, L; Dore, N; Hrdlicka, D; Hukins, C

1990-04-01

An analysis of the epidemiological factors relating to domestic flammable agents has shown that 17.7 per cent of admissions over a 5-year period were involved in domestic flammable injuries; 87.7 per cent of the patients were male, with 38.9 per cent being young males between 12 and 19 years old. Petrol and diesel accounted for 56.8 per cent of the burns and the average body surface area burned was 17.7 per cent. Most commonly the face, hands and limbs were burned, and the average length of stay was 18.25 days, 69.2 per cent of the burns were due to human error and were thus potentially preventable, 21.2 per cent had predisposing conditions with 8.9 per cent being due to alcohol. It was considered that the strategies to prevent these burns injuries should be aimed particularly at young males.

Ejection of the Massive Hydrogen-rich Envelope Timed with the Collapse of the Stripped SN 2014C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Margutti, Raffaella; Kamble, A.; Milisavljevic, D.

2017-02-01

We present multi-wavelength observations of SN 2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays ∼40 keV. SN 2014C shows ordinary explosion parameters ( E {sub k} ∼ 1.8 × 10{sup 51} erg and M {sub ej} ∼ 1.7 M{sub ⊙}). However, over an ∼1 year timescale, SN 2014C evolved from an ordinary hydrogen-poor supernova into a strongly interacting, hydrogen-rich supernova, violating the traditional classification scheme of type-I versus type-II SNe. Signatures of the SN shock interaction with a dense medium are observed across the spectrum,more » from radio to hard X-rays, and revealed the presence of a massive shell of ∼1 M {sub ⊙} of hydrogen-rich material at ∼6 × 10{sup 16} cm. The shell was ejected by the progenitor star in the decades to centuries before collapse. This result challenges current theories of massive star evolution, as it requires a physical mechanism responsible for the ejection of the deepest hydrogen layer of H-poor SN progenitors synchronized with the onset of stellar collapse. Theoretical investigations point at binary interactions and/or instabilities during the last nuclear burning stages as potential triggers of the highly time-dependent mass loss. We constrain these scenarios utilizing the sample of 183 SNe Ib/c with public radio observations. Our analysis identifies SN 2014C-like signatures in ∼10% of SNe. This fraction is reasonably consistent with the expectation from the theory of recent envelope ejection due to binary evolution if the ejected material can survive in the close environment for 10{sup 3}–10{sup 4} years. Alternatively, nuclear burning instabilities extending to core C-burning might play a critical role.« less

Unique Presentation of Orf Virus Infection in a Thermal-Burn Patient After Receiving an Autologous Skin Graft.

PubMed

Hsu, Christopher H; Rokni, Ghasem Rahmatpour; Aghazadeh, Nessa; Brinster, Nooshin; Li, Yu; Muehlenbachs, Atis; Goldsmith, Cynthia S; Zhao, Hui; Petersen, Brett; McCollum, Andrea M; Reynolds, Mary G

2016-10-15

We describe a burn patient who developed skin lesions on her skin-graft harvest and skin-graft recipient (burn) sites. Orf virus infection was confirmed by a combination of diagnostic assays, including molecular tests, immunohistochemical analysis, pathologic analysis, and electron microscopy. DNA sequence analysis grouped this orf virus isolate among isolates from India. Although no definitive source of infection was determined from this case, this is the first reported case of orf virus infection in a skin graft harvest. Skin graft recipients with exposures to animals may be at risk for this viral infection. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Influence of Non-spherical Initial Stellar Structure on the Core-Collapse Supernova Mechanism

NASA Astrophysics Data System (ADS)

Couch, Sean M.

I review the state of investigation into the impact that nonspherical stellar progenitor structure has on the core-collapse supernova mechanism. Although modeling stellar evolution relies on 1D spherically symmetric calculations, massive stars are not truly spherical. In the stellar evolution codes, this fact is accounted for by "fixes" such as mixing length theory and attendant modifications. Of particular relevance to the supernova mechanism, the Si- and O-burning shells surrounding the iron core at the point of collapse can be violently convective, with convective speeds of hundreds of km s-1. It has recently been shown by a number of groups that the presence of nonspherical perturbations in the layers surrounding the collapsing iron core can have a favorable impact on the likelihood for shock revival and explosion via the neutrino heating mechanism. This is due in large part to the strengthening of turbulence behind the stalled shock due to the presence of finite amplitude seed perturbations to speed the growth of convection which drives the post-shock turbulence. Efforts are now underway to simulate the final minutes of stellar evolution to core-collapse in 3D with the aim to generate realistic multidimensional initial conditions for use in simulations of the supernova mechanism.

Development of CFD model for augmented core tripropellant rocket engine

NASA Astrophysics Data System (ADS)

Jones, Kenneth M.

1994-10-01

The Space Shuttle era has made major advances in technology and vehicle design to the point that the concept of a single-stage-to-orbit (SSTO) vehicle appears more feasible. NASA presently is conducting studies into the feasibility of certain advanced concept rocket engines that could be utilized in a SSTO vehicle. One such concept is a tripropellant system which burns kerosene and hydrogen initially and at altitude switches to hydrogen. This system will attain a larger mass fraction because LOX-kerosene engines have a greater average propellant density and greater thrust-to-weight ratio. This report describes the investigation to model the tripropellant augmented core engine. The physical aspects of the engine, the CFD code employed, and results of the numerical model for a single modular thruster are discussed.

Surface composition changes in massive star evolution with mass loss

NASA Technical Reports Server (NTRS)

Noels, A.; Gabriel, M.; Vreux, J.-M.; Conti, P. S.

1980-01-01

A series of evolutionary models of 40-100 solar mass objects undergoing mass loss are constructed with the explicit inclusion of the surface composition of H, He, C, N, O elements. Mass loss rates similar to those observed in Of stars, 4 to 7 x 10 to the -6th solar masses/yr, result in an appearance at the surface of equilibrium CNO products, i.e. enhanced nitrogen and diminished carbon, while that star is still burning hydrogen in the core. This result obtains because the initial convection core is a relatively large fraction of the total mass and rather modest loss exposes levels of anomalous composition. It is suggested that these objects might reasonably be identified as those luminous late type WN stars still containing surface hydrogen.

Health-related quality of life (EQ-5D) early after injury predicts long-term pain after burn.

PubMed

Gauffin, Emelie; Öster, Caisa; Sjöberg, Folke; Gerdin, Bengt; Ekselius, Lisa

2016-12-01

Chronic pain after burn can have severe physical and psychological effects on former patients years after the initial injury. Although the issue of pain after burn has gained increased attention over the past years, prospective, longitudinal studies are scarce. Our aim was to prospectively investigate consecutive burn patients for pain severity over time and to evaluate the prevalence and characteristics of post-burn pain to 2-7 years after the burn. As an additional aim, the effects of burn and individual-related factors, especially health-related Quality of Life (HRQoL), were investigated. Sixty-seven consecutive burn patients were assessed during acute care at 3, 6, 12 and 24 months, as well as at 2-7 years post-burn. HRQoL, symptoms of post-traumatic stress disorder (PTSD) and other psychiatric disorders were investigated. During the interviews that took place 2-7 years after the injury (mean 4.6±1.9 years), current chronic post-burn pain was assessed using the Brief Pain Inventory-Short Form (BPI-SF). One-third of the patients still reported pain 2-7 years after the injury. Pain severity and interference with daily life were mainly mild to moderate though they were found to be associated with significantly lower HRQoL. Chronic pain after burn was associated with both burn- and individual-related factors. In logistic regression analysis HRQoL at 3 and 12 months and symptoms of PTSD at 12 months were independent factors in predicting chronic pain after burn. Pain after burn becomes a chronic burden for many former burn patients and decreases HRQoL. A novel finding in this study was that HRQoL assessed early after burn was a predictor for the development of chronic pain. This finding may help to predict future pain problems and serve as an indicator for pain preventive measures. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Factors that Affected Functional Outcome After a Delayed Excision and Split-Thickness Skin Graft on the Dorsal Side of Burned Hands.

PubMed

Shichinohe, Ryuji; Yamamoto, Yuhei; Kawashima, Kunihiro; Kimura, Chu; Ono, Kentaro; Horiuchi, Katsumi; Yoshida, Tetsunori; Murao, Naoki; Hayashi, Toshihiko; Funayama, Emi; Oyama, Akihiko; Furukawa, Hiroshi

Early excision and skin grafting is the principle treatment for a burned hand although there are occasions when it cannot be done such as severe general condition, delayed consultation, and the lack of a definitive assessment of burn depth. This study analyzes the factors that affected function after a delayed excision and skin graft for hands with a deep dermal burn. This study retrospectively evaluated 43 burned hands that required a delayed excision and split-thickness skin graft on the dorsal side. Cases were required to only have split-thickness skin grafting from the dorsum of the hand and fingers distally to at least the proximal interphalangeal joint at least 8 days after the injury. The hands were divided into two functional categories: Functional category A, normal or nearly normal joint movements, and functional category B, abnormal joint movements. Demographic data were assessed statistically by a univariate analysis following a multiple regression analysis by a stepwise selection. A significant difference was observed between the groups in the number of days from grafting to complete wound healing of the graft site and with or without an escharotomy in the analysis. These parameters were statistically significant predictors of functional category B. The functional outcome of a burned hand after a delayed excision and split-thickness skin graft on the dorsal side became degraded depending on the number of days from grafting to complete wound healing. Cases that underwent an escharotomy also showed deterioration in function.

Functional Group Analysis of Biomass Burning Particles Using Infrared Spectroscopy

NASA Astrophysics Data System (ADS)

Horrell, K.; Lau, A.; Bond, T.; Iraci, L. T.

2008-12-01

Biomass burning is a significant source of particulate organic carbon in the atmosphere. These particles affect the energy balance of the atmosphere directly by absorbing and scattering solar radiation, and indirectly through their ability to act as cloud condensation nuclei (CCN). The chemical composition of biomass burning particles influences their ability to act as CCN, thus understanding the chemistry of these particles is required for understanding their effects on climate and air quality. As climate change influences the frequency and severity of boreal forest fires, the influence of biomass burning aerosols on the atmosphere may become significantly greater. Only a small portion of the organic carbon (OC) fraction of these particles has been identified at the molecular level, although several studies have explored the general chemical classes found in biomass burning smoke. To complement those studies and provide additional information about the reactive functional groups present, we are developing a method for polarity-based separation of compound classes found in the OC fraction, followed by infrared (IR) spectroscopic analysis of each polarity fraction. It is our goal to find a simple, relatively low-tech method which will provide a moderate chemical understanding of the entire suite of compounds present in the OC fraction of biomass burning particles. Here we present preliminary results from pine and oak samples representative of Midwestern United States forests burned at several different temperatures. Wood type and combustion temperature are both seen to affect the composition of the particles. The latter seems to affect relative contributions of certain functional groups, while oak demonstrates at least one additional chemical class of compounds, particularly at lower burning temperatures, where gradual solid-gas phase reactions can produce relatively large amounts of incompletely oxidized products.

Moderate glycemic control safe in critically ill adult burn patients: A 15 year cohort study.

PubMed

Stoecklin, Patricia; Delodder, Frederik; Pantet, Olivier; Berger, Mette M

2016-02-01

Hyperglycemia is a metabolic alteration in major burn patients associated with complications. The study aimed at evaluating the safety of general ICU glucose control protocols applied in major burns receiving prolonged ICU treatment. 15 year retrospective analysis of consecutive, adult burn patients admitted to a single specialized centre. death or length of stay <10 days, age <16 years. demographic variables, burned surface (TBSA), severity scores, infections, ICU stay, outcome. Metabolic variables: total energy, carbohydrate and insulin delivery/24h, arterial blood glucose and CRP values. Analysis of 4 periods: 1, before protocol; 2, tight doctor driven; 3, tight nurse driven; 4, moderate nurse driven. 229 patients, aged 45 ± 20 years (mean ± SD), burned 32 ± 20% TBSA were analyzed. SAPSII was 35 ± 13. TBSA, Ryan and ABSI remained stable. Inhalation injury increased. A total of 28,690 blood glucose samples were analyzed: the median value remained unchanged with a narrower distribution over time. After the protocol initiation, the normoglycemic values increased from 34.7% to 65.9%, with a reduction of hypoglycaemic events (no extreme hypoglycemia in period 4). Severe hyperglycemia persisted throughout with a decrease in period 4 (9.25% in period 4). Energy and glucose deliveries decreased in periods 3 and 4 (p<0.0001). Infectious complications increased during the last 2 periods (p=0.01). A standardized ICU glucose control protocol improved the glycemic control in adult burn patients, reducing glucose variability. Moderate glycemic control in burns was safe specifically related to hypoglycemia, reducing the incidence of hypoglycaemic events compared to the period before. Hyperglycemia persisted at a lower level. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

IMPLICATIONS OF RAPID CORE ROTATION IN RED GIANTS FOR INTERNAL ANGULAR MOMENTUM TRANSPORT IN STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tayar, Jamie; Pinsonneault, Marc H., E-mail: tayar.1@osu.edu

2013-09-20

Core rotation rates have been measured for red giant stars using asteroseismology. These data, along with helioseismic measurements and open cluster spin-down studies, provide powerful clues about the nature and timescale for internal angular momentum transport in stars. We focus on two cases: the metal-poor red giant KIC 7341231 ({sup O}tto{sup )} and intermediate-mass core helium burning stars. For both, we examine limiting case studies for angular momentum coupling between cores and envelopes under the assumption of rigid rotation on the main sequence. We discuss the expected pattern of core rotation as a function of mass and radius. In themore » case of Otto, strong post-main-sequence coupling is ruled out and the measured core rotation rate is in the range of 23-33 times the surface value expected from standard spin-down models. The minimum coupling timescale (0.17-0.45 Gyr) is significantly longer than that inferred for young open cluster stars. This implies ineffective internal angular momentum transport in early first ascent giants. By contrast, the core rotation rates of evolved secondary clump stars are found to be consistent with strong coupling given their rapid main-sequence rotation. An extrapolation to the white dwarf regime predicts rotation periods between 330 and 0.0052 days, depending on mass and decoupling time. We identify two key ingredients that explain these features: the presence of a convective core and inefficient angular momentum transport in the presence of larger mean molecular weight gradients. Observational tests that can disentangle these effects are discussed.« less

The Hand Burn Severity (HABS) score: A simple tool for stratifying severity of hand burns.

PubMed

Bache, Sarah E; Fitzgerald O'Connor, Edmund; Theodorakopoulou, Evgenia; Frew, Quentin; Philp, Bruce; Dziewulski, Peter

2017-02-01

Hand burns represent a unique challenge to the burns team due to the intricate structure and unrivalled functional importance of the hand. The initial assessment and prognosis relies on consideration of the specific site involved as well as depth of the burn. We created a simple severity score that could be used by referring non-specialists and researchers alike. The Hand Burn Severity (HABS) score stratifies hand burns according to severity with a numerical value of between 0 (no burn) and 18 (most severe) per hand. Three independent assessors scored the photographs of 121 burned hands of 106 adult and paediatric patients, demonstrating excellent inter-rater reliability (r=0.91, p<0.0001 on testing with Lin's correlation coefficient). A significant relationship was shown between the HABS score and a reliable binary outcome of the requirement for surgical excision on Mann-Whitney U testing (U=152; Z=9.8; p=0.0001). A receiver operator characteristic (ROC) curve analysis found a cut off score of 5.5, indicating that those with a HABS score below 6 did not require an operation, whereas those with a score above 6 did. The HABS score was shown to be more sensitive and specific that assessment of burn depth alone. The HABS score is a simple to use tool to stratify severity at initial presentation of hand burns which will be useful when referring, and when reporting outcomes. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Burn injuries related to motorcycle exhaust pipes: a study in Greece.

PubMed

Matzavakis, Ioannis; Frangakis, Constantine E; Charalampopoulou, Ava; Petridou, Eleni

2005-05-01

To identify measures that should reduce the incidence of burn injuries resulting from motorcycle exhaust pipes through epidemiological analysis of such injuries. During a 5-year period, 251 persons who suffered burn injuries related to motorcycle exhaust pipes have contacted four major hospitals belonging to the Emergency Department Injury Surveillance System (EDISS) operating since 1996 in Greece. These burn injuries were studied in relation to person, environment and vehicle characteristics. The estimated countrywide incidence of burns from motorcycle exhaust pipes was 17 per 100,000 person-years (208 per 100,000 motorcycle-years). The incidence was two times higher for children than for older persons and among the latter it was 60% higher among females than among males. Most of burn injuries (70.5%) concerned motorcycle passengers, mainly when getting on or off motorcycle, with peak incidence during summer. The most frequent location of burn wounds was below the knee and particularly the right leg. It was estimated that the risk of motorcycle exhaust pipe burns when wearing shorts could be reduced by 46% through wearing long pants. Among the victims 65.3% experienced second degree burns. Motorcycle exhaust burns could be substantially reduced by systematically wearing long pants, by incorporating in the design of motorcycles external thermo resistant shields with adequate distance to the exhaust pipe, and by avoiding riding with children on motorcycles.

Quantifying bacterial transfer from patients to staff during burns dressing and bed changes: implications for infection control.

PubMed

Bache, Sarah E; Maclean, Michelle; Gettinby, George; Anderson, John G; MacGregor, Scott J; Taggart, Ian

2013-03-01

Routine nursing activities such as dressing/bed changes increase bacterial dispersal from burns patients, potentially contaminating healthcare workers (HCW) carrying out these tasks. HCW thus become vectors for transmission of nosocomial infection between patients. The suspected relationship between %total body surface area (%TBSA) of burn and levels of bacterial release has never been fully established. Bacterial contamination of HCW was assessed by contact plate samples (n=20) from initially sterile gowns worn by the HCW during burns patient dressing/bed changes. Analysis of 24 gowns was undertaken and examined for relationships between %TBSA, time taken for activity, and contamination received by the HCW. Relationships between size of burn and levels of HCW contamination, and time taken for the dressing/bed change and levels of HCW contamination were best described by exponential models. Burn size correlated more strongly (R(2)=0.82, p<0.001) than time taken (R(2)=0.52, p<0.001), with levels of contamination received by the HCW. Contamination doubled with every 6-9% TBSA increase in burn size. Burn size was used to create a model to predict bacterial contamination received by a HCW carrying out bed/dressing changes. This may help with the creation of burn-specific guidelines on protective clothing worn by HCW caring for burns patients. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

A comparative analysis of potential impact area of common sugar cane burning methods

NASA Astrophysics Data System (ADS)

Hiscox, A. L.; Flecher, S.; Wang, J. J.; Viator, H. P.

2015-04-01

The negative effects of agricultural burning are well-known, although the actual impact area of different activities has not previously been quantified. An elastic backscatter lidar system was used to examine the impact-area size and dispersion of smoke generated from different types of sugarcane burning activities; pre-harvest (standing) burning and post-harvest (ground) burning. Experiments were conducted in the sugarcane harvest season of 2010 and 2011 at two locations in Louisiana, USA. Current dispersion theory would suggest that the primary difference between burn types would be primarily in the initial plume rise, but that the overall plume shape would remain the same. However, remotely sensed lidar data with the capability to measure plume dispersion and the short time dynamics of plume location showed pre-harvest (standing) burning produced a larger plume with greater rise and more spread within the 300 m of the plume, but a decrease in dispersion, but not concentration further downwind. Post-harvest (ground) burning produced a more traditional plume shape, but still exceeded impact area predictions near the source. Moreover, large changes in plume size can occur with small increases in wind speed. These are the first instrumented measurements of the meteorological effects of the different types of sugarcane burning. These results indicate that ground burning is preferable, but should be avoided in lower wind speed conditions.

Correlation between incidences of self-inflicted burns and means of inbreeding coefficients, an ecologic study.

PubMed

Saadat, Mostafa; Zendeh-Boodi, Zahra

2006-09-01

The aim of the study is to obtain more insight into the possible association between consanguinity and the incidence of deliberate self-burning. Data were obtained by analysis of medical records of patients hospitalized in two referral burn centers: Chormy Burn Center (Bushehr Province, south of Iran) from March 21, 1998, through March 20, 2004, and Shahid Sadoqi Center of Burns and Injuries (Yazd Province, center of Iran) from March 21, 2000, through March 20, 2004. The incidence of suicidal burns was 6.51 and 2.32/100,000 person-years for Bushehr and Yazd Provinces, respectively. The observed sex ratio of patients in both centers indicated there was a female predominance in patients with self-inflicted burns. Using patients' home addresses, patients were sorted into 16 cities. The incidence of suicide by self-burning ranged from 0.80 (for Tabas, located in Yazd Province) to 12.60/100,000 person-years (for Dilam, located in Bushehr Province). The coefficient of inbreeding defines the probability that an individual received both alleles of a pair from an identical ancestral source. There was a significant correlation between incidences of suicidal burns and mean coefficient of inbreeding (r = 0.782, df = 14, p < 0.001). In addition to other factors, consanguineous marriage may be a risk factor that influences the incidence of suicidal burns in a population.