Canopy warming caused photosynthetic acclimation and reduced seed yield in maize grown at ambient and elevated [CO2

USDA-ARS?s Scientific Manuscript database

Rising atmospheric CO2 concentration ([CO2]) and attendant increases in growing season temperature are expected be the most important global change factors impacting production agriculture. Although maize is the most highly produced crop worldwide, few studies have evaluated the interactive effects ...

Using Nitrogen Stable Isotope Tracers to Track Climate Change Impacts on Coastal Salt Marshes

EPA Science Inventory

Climate change impacts on coastal salt marshes are predicted to be complex and multi-faceted. In addition to rising sea level and warmer water temperatures, regional precipitation patterns are also expected to change. At least in the Northeast and Mid-Atlantic U.S., more severe s...

Stochastic heating of a single Brownian particle by charge fluctuations in a radio-frequency produced plasma sheath

NASA Astrophysics Data System (ADS)

Schmidt, Christian; Piel, Alexander

2015-10-01

The Brownian motion of a single particle in the plasma sheath is studied to separate the effect of stochastic heating by charge fluctuations from heating by collective effects. By measuring the particle velocities in the ballistic regime and by carefully determining the particle mass from the Epstein drag it is shown that for a pressure of 10 Pa, which is typical of many experiments, the proper kinetic temperature of the Brownian particle remains close to the gas temperature and rises only slightly with particle size. This weak effect is confirmed by a detailed model for charging and charge fluctuations in the sheath. A substantial temperature rise is found for decreasing pressure, which approximately shows the expected scaling with p-2. The system under study is an example for non-equilibrium Brownian motion under the influence of white noise without corresponding dissipation.

Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers.

PubMed

Follstad Shah, Jennifer J; Kominoski, John S; Ardón, Marcelo; Dodds, Walter K; Gessner, Mark O; Griffiths, Natalie A; Hawkins, Charles P; Johnson, Sherri L; Lecerf, Antoine; LeRoy, Carri J; Manning, David W P; Rosemond, Amy D; Sinsabaugh, Robert L; Swan, Christopher M; Webster, Jackson R; Zeglin, Lydia H

2017-08-01

Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community responses to temperature, factors that can influence the apparent temperature sensitivity of breakdown and the relative proportion of C lost to the atmosphere vs. stored or transported downstream. Here, we synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity, as measured by the activation energy (E a , in eV). Temperature sensitivity of litter breakdown varied among twelve plant genera for which E a could be calculated. Higher values of E a were correlated with lower-quality litter, but these correlations were influenced by a single, N-fixing genus (Alnus). E a values converged when genera were classified into three breakdown rate categories, potentially due to continual water availability in streams and rivers modulating the influence of leaf chemistry on breakdown. Across all data representing 85 plant genera, the E a was 0.34 ± 0.04 eV, or approximately half the value (0.65 eV) predicted by metabolic theory. Our results indicate that average breakdown rates may increase by 5-21% with a 1-4 °C rise in water temperature, rather than a 10-45% increase expected, according to metabolic theory. Differential warming of tropical and temperate biomes could result in a similar proportional increase in breakdown rates, despite variation in E a values for these regions (0.75 ± 0.13 eV and 0.27 ± 0.05 eV, respectively). The relative proportions of gaseous C loss and organic matter transport downstream should not change with rising temperature given that E a values for breakdown mediated by microbes alone and microbes plus detritivores were similar at the global scale. © 2017 John Wiley & Sons Ltd.

Estimating Vector-borne Viral Infections in the Urban Setting of the 2020 Tokyo Olympics, Japan, Using Mathematical Modeling.

PubMed

Furuya, Hiroyuki

2017-12-20

The first domestic outbreak of dengue fever in Japan since 1945 was reported in Tokyo in 2014. Meanwhile, daily mean summer temperatures are expected to continue to rise world-wide. Such conditions are expected to increase the risk of an arbovirus outbreak at the 2020 Tokyo Olympic Games. To address this possibility, the present study compared estimates of the risk of infection by dengue, chikungunya, and Zika viruses in urban areas. To compare the risk of infection by arboviruses transmitted by Ae. albopictus mosquitoes, the reproduction number for each of three arboviruses was estimated under the environmental conditions associated with the 2014 dengue outbreak in Tokyo, and additionally under conditions assuming a daily mean temperature elevation of 2° C. For dengue, chikungunya, and Zika, the estimated distributions of R 0 were independently fitted to gamma distributions yielding median R 0 values of 1.00, 0.46, and 0.36, respectively. If the daily mean temperature were to rise from 28° C to 30° C, our model predicts increases of the median R 0 of 18% for dengue, 4.3% for chikungunya, and 11.1% for Zika. Strengthening of the public health responsivity for these emerging arboviral diseases will be needed in preparation for the 2020 Olympic Games in Tokyo.

Initial aging phenomena in copper-chromium alloys

NASA Technical Reports Server (NTRS)

Suzuki, H.; Motohiro, K.

1985-01-01

The effects of quenching and aging temperatures on the initial aging curves of Cu-Cr alloy were examined mainly by means of electrical resistivity measurements. Three Cu-Cr alloy specimens having 0.24, 0.74, and 1.0% Cr were solution-treated at 950-1050 C, quenched into ice-water, and subsequently aged at 300-500 C. The results were as follows: (1) At the very early stage of aging (within about 30 sec), an abrupt decrease of resistivity with lowering aging tempratures. (T sub A) and rising solution temperatures (T sub S) was observed at (T sub A) up to about 400 C. In contrast, a transient increase of resistivity with rising T sub A and lowering T sub S was observed at T sub A from about 450 to 500 C. These phenomena seem to be caused by a rapid formation of solute clusters and the reversion of clusters formed during quenching, which are enhanced by quenched-in vacancies, respectively. (2) The amount of precipitation increased at the latter stage of aging with rising T sub S and T sub A as generally expected, where T sub S was not so high as to form secondary defects. (3) As a result, the initial aging phenomena in Cr-Cr alloy were revealed to be complicated against expectations. This was considered to be due to the migration energy of vacancies so larger in Cu-base.

Plant molecular responses to the elevated ambient temperatures expected under global climate change.

PubMed

Fei, Qionghui; Li, Jingjing; Luo, Yunhe; Ma, Kun; Niu, Bingtao; Mu, Changjun; Gao, Huanhuan; Li, Xiaofeng

2018-01-02

Environmental temperatures affect plant distribution, growth, and development. The Intergovernmental Panel on Climate Change (IPCC) predicts that global temperatures will rise by at least 1.5°C by the end of this century. Global temperature changes have already had a discernable impact on agriculture, phenology, and ecosystems. At the molecular level, extensive literature exists on the mechanism controlling plant responses to high temperature stress. However, few studies have focused on the molecular mechanisms behind plant responses to mild increases in ambient temperature. Previous research has found that moderately higher ambient temperatures can induce hypocotyl elongation and early flowering. Recent evidence demonstrates roles for the phytohormones auxin and ethylene in adaptive growth of plant roots to slightly higher ambient temperatures.

Effects of CDS and Drying Temperature Levels on the Flowability Behavior of DDGS

USDA-ARS?s Scientific Manuscript database

The fuel ethanol industry has been one of the fastest growing industries, with a growth rate of more than 300% since 2000. Due to demand for alternative fuels and the need to reduce dependence on fossil fuels, the growth of ethanol production is expected to rise in future years. One of the problems ...

Projections of Seasonal Patterns in Temperature- Related Deaths for Manhattan, New York

NASA Technical Reports Server (NTRS)

Li, Tiantian; Horton, Radley M.; Kinney, Patrick L.

2013-01-01

Global average temperatures have been rising for the past half-century, and the warming trend has accelerated in recent decades. Further warming is expected over the next few decades, with significant regional variations. These warming trends will probably result in more frequent, intense and persistent periods of hot temperatures in summer, and generally higher temperatures in winter. Daily death counts in cities increase markedly when temperatures reach levels that are very high relative to what is normal in a given location. Relatively cold temperatures also seem to carry risk. Rising temperatures may result in more heat-related mortality but may also reduce cold-related mortality, and the net impact on annual mortality remains uncertain. Here we use 16 downscaled global climate models and two emissions scenarios to estimate present and future seasonal patterns in temperature-related mortality in Manhattan, New York. All 32 projections yielded warm-season increases and cold-season decreases in temperature-related mortality, with positive net annual temperature-related deaths in all cases. Monthly analyses showed that the largest percentage increases may occur in May and September. These results suggest that, over a range of models and scenarios of future greenhouse gas emissions, increases in heat-related mortality could outweigh reductions in cold-related mortality, with shifting seasonal patterns.

Extreme sea level implications of 1.5 °C, 2.0 °C, and 2.5 °C temperature stabilization targets in the 21st and 22nd centuries

NASA Astrophysics Data System (ADS)

Rasmussen, D. J.; Bittermann, Klaus; Buchanan, Maya K.; Kulp, Scott; Strauss, Benjamin H.; Kopp, Robert E.; Oppenheimer, Michael

2018-03-01

Sea-level rise (SLR) is magnifying the frequency and severity of extreme sea levels (ESLs) that can cause coastal flooding. The rate and amount of global mean sea-level (GMSL) rise is a function of the trajectory of global mean surface temperature (GMST). Therefore, temperature stabilization targets (e.g. 1.5 °C and 2.0 °C of warming above pre-industrial levels, as from the Paris Agreement) have important implications for coastal flood risk. Here, we assess, in a global network of tide gauges, the differences in the expected frequencies of ESLs between scenarios that stabilize GMST warming at 1.5 °C, 2.0 °C, and 2.5 °C above pre-industrial levels. We employ probabilistic, localized SLR projections and long-term hourly tide gauge records to estimate the expected frequencies of historical and future ESLs for the 21st and 22nd centuries. By 2100, under 1.5 °C, 2.0 °C, and 2.5 °C GMST stabilization, the median GMSL is projected to rise 48 cm (90% probability of 28-82 cm), 56 cm (28-96 cm), and 58 cm (37-93 cm), respectively. As an independent comparison, a semi-empirical sea level model calibrated to temperature and GMSL over the past two millennia estimates median GMSL rise within 7-8 cm of these projections. By 2150, relative to the 2.0 °C scenario and based on median sea level projections, GMST stabilization of 1.5 °C spares the inundation of lands currently home to about 5 million people, including 60 000 individuals currently residing in Small Island Developing States. We quantify projected changes to the expected frequency of historical 10-, 100-, and 500-year ESL events using frequency amplification factors that incorporate uncertainty in both local SLR and historical return periods of ESLs. By 2150, relative to a 2.0 °C scenario, the reduction in the frequency amplification of the historical 100 year ESL event arising from a 1.5 °C GMST stabilization is greatest in the eastern United States, with ESL event frequency amplification being reduced by about half at most tide gauges. In general, smaller reductions are projected for Small Island Developing States.

Neutron Resonance Spectrometry Shock Temperatures in Molybdenum

NASA Astrophysics Data System (ADS)

Swift, Damian; Seifter, Achim; Holtkamp, David; Yuan, Vincent; Clark, David; Buttler, William

2007-06-01

Neutron resonance spectrometry (NRS) has been used to measure the temperature in Mo during shock loading, giving temperatures higher than expected. The effect of plastic flow and non-ideal projectile behavior were assessed. Plastic flow was estimated to contribute a temperature rise of 55K compared with hydrodynamic flow, and 100-150K on release, consistent with pyrometry measurements. Simulations were performed of the HE flyer system used to induce the shock in the Mo sample. The simulations predicted that the flyer was slightly curved on impact. The resulting spatial variations in load, including radial components of velocity, were predicted to increase the apparent NRS temperature by 160K. These corrections are sufficient to reconcile the apparent temperatures deduced using NRS with the accepted properties of Mo.

The competing impacts of climate change and nutrient reductions on dissolved oxygen in Chesapeake Bay

NASA Astrophysics Data System (ADS)

Irby, Isaac D.; Friedrichs, Marjorie A. M.; Da, Fei; Hinson, Kyle E.

2018-05-01

The Chesapeake Bay region is projected to experience changes in temperature, sea level, and precipitation as a result of climate change. This research uses an estuarine-watershed hydrodynamic-biogeochemical modeling system along with projected mid-21st-century changes in temperature, freshwater flow, and sea level rise to explore the impact climate change may have on future Chesapeake Bay dissolved-oxygen (DO) concentrations and the potential success of nutrient reductions in attaining mandated estuarine water quality improvements. Results indicate that warming bay waters will decrease oxygen solubility year-round, while also increasing oxygen utilization via respiration and remineralization, primarily impacting bottom oxygen in the spring. Rising sea level will increase estuarine circulation, reducing residence time in bottom waters and increasing stratification. As a result, oxygen concentrations in bottom waters are projected to increase, while oxygen concentrations at mid-depths (3 < DO < 5 mg L-1) will typically decrease. Changes in precipitation are projected to deliver higher winter and spring freshwater flow and nutrient loads, fueling increased primary production. Together, these multiple climate impacts will lower DO throughout the Chesapeake Bay and negatively impact progress towards meeting water quality standards associated with the Chesapeake Bay Total Maximum Daily Load. However, this research also shows that the potential impacts of climate change will be significantly smaller than improvements in DO expected in response to the required nutrient reductions, especially at the anoxic and hypoxic levels. Overall, increased temperature exhibits the strongest control on the change in future DO concentrations, primarily due to decreased solubility, while sea level rise is expected to exert a small positive impact and increased winter river flow is anticipated to exert a small negative impact.

Behavioral responses of Atlantic cod to sea temperature changes.

PubMed

Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

2015-05-01

Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30-80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species.

Behavioral responses of Atlantic cod to sea temperature changes

PubMed Central

Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

2015-01-01

Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30–80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species. PMID:26045957

Estimating extreme stream temperatures by the standard deviate method

NASA Astrophysics Data System (ADS)

Bogan, Travis; Othmer, Jonathan; Mohseni, Omid; Stefan, Heinz

2006-02-01

It is now widely accepted that global climate warming is taking place on the earth. Among many other effects, a rise in air temperatures is expected to increase stream temperatures indefinitely. However, due to evaporative cooling, stream temperatures do not increase linearly with increasing air temperatures indefinitely. Within the anticipated bounds of climate warming, extreme stream temperatures may therefore not rise substantially. With this concept in mind, past extreme temperatures measured at 720 USGS stream gauging stations were analyzed by the standard deviate method. In this method the highest stream temperatures are expressed as the mean temperature of a measured partial maximum stream temperature series plus its standard deviation multiplied by a factor KE (standard deviate). Various KE-values were explored; values of KE larger than 8 were found physically unreasonable. It is concluded that the value of KE should be in the range from 7 to 8. A unit error in estimating KE translates into a typical stream temperature error of about 0.5 °C. Using a logistic model for the stream temperature/air temperature relationship, a one degree error in air temperature gives a typical error of 0.16 °C in stream temperature. With a projected error in the enveloping standard deviate dKE=1.0 (range 0.5-1.5) and an error in projected high air temperature d Ta=2 °C (range 0-4 °C), the total projected stream temperature error is estimated as d Ts=0.8 °C.

Estimation of sediment friction coefficient from heating upon APC penetration during the IODP NanTroSEIZE

NASA Astrophysics Data System (ADS)

Kinoshita, M.; Kawamura, K.; Lin, W.

2015-12-01

During the Nankai Trough Seismogenic Zone Experiments (NanTroSEIZE) of the Integrated Ocean Drilling Program (IODP), the advanced piston corer temperature (APC-T) tool was used to determine in situ formation temperatures while piston coring down to ~200 m below sea floor. When the corer is fired into the formation, temperature around the shoe abruptly increases due to the frictional heating. The temperature rise due to the frictional heat at the time of penetration is 10 K or larger. We found that the frictional temperature rise (=maximum temperature) increases with increasing depth, and that its intersection at the seafloor seems non-zero. Frictional heat energy is proportional to the maximum temperature rise, which is confirmed by a FEM numerical simulation of 2D cylindrical system. Here we use the result of numerical simulation to convert the observed temperature rise into the frictional heat energy. The frictional heat energy is represented as the product of the shooting length D and the shear stress (τ) between the pipe and the sediment. Assuming a coulomb slip regime, the shear stress is shows as: τ= τ0 + μ*(Sv-Pp), where τ0 is the cohesive stress, μ the dynamic frictional coefficient between the pipe and the sediment, Sv the normal stress at the pipe, and Pp the pore pressure. This can explain the non-zero intersection as well as depth-dependent increase for the frictional heating observed in the APC-T data. Assuming a hydrostatic state and by using the downhole bulk density data, we estimated the friction coefficient for each APC-T measurement. For comparison, we used the vane-shear strength measured on core samples to estimate the friction coefficients. The frictional coefficients μ were estimated as ranging 0.01 - 0.06, anomalously lower than expected for shallow marine sediments. They were lower than those estimated from vane-shear data, which range 0.05 to 0.2. Still, both estimates exhibit a significant increase in the friction coefficient at Site C0012, which dominates in the hemipelagic sediment in the Shikoku Basin. The anomalously low values suggest either fluid injection between the pipe and the sediment during the measurement, or some other uncertainties in converting the observed temperature rise to the frictional heat generation.

Parity-violating hybridization in heavy Weyl semimetals

NASA Astrophysics Data System (ADS)

Chang, Po-Yao; Coleman, Piers

2018-04-01

We introduce a simple model to describe the formation of heavy Weyl semimetals in noncentrosymmetric heavy fermion compounds under the influence of a parity-mixing, onsite hybridization. A key aspect of interaction-driven heavy Weyl semimetals is the development of surface Kondo breakdown, which is expected to give rise to a temperature-dependent reconfiguration of the Fermi arcs and the Weyl cyclotron orbits which connect them via the chiral bulk states. Our theory predicts a strong temperature-dependent transformation in the quantum oscillations at low temperatures. In addition to the effects of surface Kondo breakdown, the renormalization effects in heavy Weyl semimetals will appear in a variety of thermodynamic and transport measurements.

Future sea level rise constrained by observations and long-term commitment.

PubMed

Mengel, Matthias; Levermann, Anders; Frieler, Katja; Robinson, Alexander; Marzeion, Ben; Winkelmann, Ricarda

2016-03-08

Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28-56 cm, 37-77 cm, and 57-131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The "constrained extrapolation" approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections.

Future sea level rise constrained by observations and long-term commitment

PubMed Central

Mengel, Matthias; Levermann, Anders; Frieler, Katja; Robinson, Alexander; Marzeion, Ben; Winkelmann, Ricarda

2016-01-01

Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28–56 cm, 37–77 cm, and 57–131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The “constrained extrapolation” approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections. PMID:26903648

Effects of elevated temperature on coral reef fishes: loss of hypoxia tolerance and inability to acclimate.

PubMed

Nilsson, Göran E; Ostlund-Nilsson, Sara; Munday, Philip L

2010-08-01

Water temperature is expected to rise on coral reefs due to global warming. Here, we have examined if increased temperature reduces the hypoxia tolerance of coral reef fish (measured as critical [O(2)]), and if temperature acclimation in adults can change the resting rate of O(2) consumption and critical [O(2)]. Two common species from Lizard Island (Great Barrier Reef, Australia) were tested, Doederlein's cardinalfish (Ostorhinchus doederleini) and lemon damselfish (Pomacentrus moluccensis). In both species, a 3 degrees C rise in water temperature caused increased oxygen consumption and reduced hypoxia tolerance, changes that were not reduced by acclimation to the higher temperature for 7 to 22 days. Critical [O(2)] increased by 71% in the cardinalfish and by 23% in the damselfish at 32 degrees C compared to 29 degrees C. The higher oxygen needs are likely to reduce the aerobic scope, which could negatively affect the capacity for feeding, growth and reproduction. The reduced hypoxia tolerance may force the fishes out of their nocturnal shelters in the coral matrix, exposing them to predation. The consequences for population and species survival could be severe unless developmental phenotypic plasticity within generations or genetic adaptation between generations could produce individuals that are more tolerant to a warmer future. Copyright (c) 2010 Elsevier Inc. All rights reserved.

New estimates of temperature response of leaf photosynthesis in Amazon forest trees, its acclimation to mean temperature change and consequences for modelling climate response to rain forests.

NASA Astrophysics Data System (ADS)

Kruijt, B.; Jans, W.; Vasconcelos, S.; Tribuzy, E. S.; Felsemburgh, C.; Eliane, M.; Rowland, L.; da Costa, A. C. L.; Meir, P.

2014-12-01

In many dynamic vegetation models, degradation of the tropical forests is induced because they assume that productivity falls rapidly when temperatures rise in the region of 30-40°C. Apart plant respiration, this is due to the assumptions on the temperature optima of photosynthetic capacity, which are low and can differ widely between models, where in fact hardly any empirical information is available for tropical forests. Even less is known about the possibility that photosynthesis will acclimate to changing temperatures. The objective of this study to is to provide better estimates for optima, as well as to determine whether any acclimation to temperature change is to be expected. We present both new and hitherto unpublished data on the temperature response of photosynthesis of Amazon rainforest trees, encompassing three sites, several species and five field campaigns. Leaf photosynthesis and its parameters were determined at a range of temperatures. To study the long-term (seasonal) acclimation of this response, this was combined with an artificial, in situ, multi-season leaf heating experiment. The data show that, on average for all non-heated cases, the photosynthetic parameter Vcmax weakly peaks between 35 and 40 ˚C, while heating does not have a clearly significant effect. Results for Jmax are slightly different, with sharper peaks. Scatter was relatively high, which could indicate weak overall temperature dependence. The combined results were used to fit new parameters to the various temperature response curve functions in a range of DGVMs. The figure shows a typical example: while the default Jules model assumes a temperature optimum for Vcmax at around 33 ˚C, the data suggest that Vcmax keeps rising up to at least 40 ˚C. Of course, calculated photosynthesis, obtained by applying this Vcmax in the Farquhar model, peaks at lower temperature. Finally, the implication of these new model parameters for modelled climate change impact on modelled Amazon forests will be assessed, where it is expected that predicted die-back will be less.

Family size and expectations about housing in the later nineteenth century: three Yorkshire towns.

PubMed

Atkinson, Paul

2011-01-01

This article illustrates how cultural history can deepen the understanding of demographic change, presenting evidence about ways in which rising working-class expectations about appropriate living standards may have created additional pressures on the perceived costs of child-rearing. Among the key areas of family consumption, housing costs are selected for examination. It is shown that higher expectations about appropriate housing quality put pressure on family budgets, augmented by the rising cost of like-for-like housing. The discussion considers expectations about the size of the dwelling and attitudes to furnishing the home, and suggests that these rising expectations helped encourage family limitation. Existing accounts of the fertility decline which stress the role of rising expectations are often too generalised: this article illustrates what can be gained by adding detail and geographical variation.

N cycling in SPRUCE (Spruce Peatlands Response Under ...

EPA Pesticide Factsheets

Peatlands located in boreal regions make up a third of global wetland area and are expected to have the highest temperature increases in response to climate change. As climate warms, we expect peat decomposition may accelerate, altering the cycling of nitrogen. Alterations in the nitrogen cycle can have consequences on NO3, NH4 availability or pollution, and potentially increase nitrous oxide (N2O) emissions, a persistent greenhouse gas (GHG). These consequences can cascade to altering whole ecosystem functions and effecting human health.We are investigating nitrogen cycling response to elevated temperature and CO2 in a boreal peatland. Spruce and Peatland Responses Under Climate and Environmental Change (SPRUCE) project initiated soil warming in 2014 in ten peatland mesocosms (five temperature treatments from ambient (+0°C) to +9°C) and elevated CO2 in half of the mesocosms in 2016. Peat cores at three depths (acrotelm, catotelm, deep peat) were analyzed in the laboratory for denitrification, nitrification, and ammonification. We expect denitrification, nitrification, and ammonification rates to increase, and denitrification efficiency to decrease with rising temperatures- potentially contaminating water resources with NO3, NH4 and increase N2O concentrations in our atmosphere. This research will enhance the scientific understanding of how nitrogen cycling, an important functional eco-service, responds under environmental conditions including elevated CO2

Sea surface temperature 1871-2099 in 14 cells around the United Kingdom.

PubMed

Sheppard, Charles

2004-07-01

Monthly sea surface temperature is provided for 14 locations around the UK for a 230 year period. These series are derived from the HadISST1 data set for historical time (1871-1999) and from the HadCM3 climate model for predicted SST (1950-2099). Two adjustments of the forecast data sets are needed to produce confluent SST series: the 50 year overlap is used for a gross adjustment, and a statistical scaling on the forecast data ensures that annual variations in forecast data match those of historical data. These monthly SST series are available on request. The overall rise in SST over time is clear for all sites, commencing in the last quarter of the 20th century. Apart from expected trends of overall warmer mean SST with more southerly latitudes and overall cooler mean SST towards the East, more interesting statistically significant general trends include a greater decadal rate of rise from warmer starting conditions. Annual temperature variation is not affected by absolute temperature, but is markedly greater towards the East. There is no correlation of annual range of SST with latitude, or with present SST values.

Study of temperature rises and forces on drilling bone

NASA Astrophysics Data System (ADS)

Srikanth Venkataraman, Ananya

Many different approaches have been used to prepare, store and test bone samples in order to determine its physical properties. The need to establish a standard method of specimen preparation and storage prior to experimental testing, contributed greatly to the primary part of this study. When mechanized cutting tools such as saws and drills are used, heat is produced and this raises the temperature of both the tool and the material being cut. In orthopedic and dental practices, high-speed tools are often applied to bones and teeth, and heat from these operations may result in thermal necrosis [1]. Since this can have a negative impact on the outcome of an orthopedic procedure, temperatures must be kept below the threshold that results in bone necrosis. The initial set of experiments was performed to determine the conditions under which the mechanical properties of the bone changed so as to establish the most suitable testing conditions. The hardness variation of the bone samples, under different annealing treatment conditions was used as the indicating parameter for evaluation of the change in the mechanical properties. Establishing the most appropriate section of the metacarpal sample for testing, by studying the anisotropy of the bone was another determining parameter. The second step was to examine the effects of conventional drilling as well as modulation assisted drilling on the temperature rise generated in the bone during these machining processes. In addition to this, a set of experiments were performed to ascertain how lubrication affected the temperature rise during drilling. The dynamic portions of the torque and thrust traces as well as the specific energies were compared for the different drilling conditions. Modulation showed no significant effect on the mean torque, thrust, specific energies of cutting, or temperature rise. Lubrication (flooding and misting) in both the modulation and no modulation cases drastically reduced the temperature rise during cutting, as expected. In addition to this the characteristics of the chips produced by both the methods of drilling were compared. The modulation process produced more consistent chips at the lower speed (360 rpm) and as the speed was increased to 3000 rpm the chip formation was similar to the no modulation drilling condition at the same feed rates. A brief study on the histological changes due to drilling was also performed.

Sea-level rise and its possible impacts given a 'beyond 4°C world' in the twenty-first century.

PubMed

Nicholls, Robert J; Marinova, Natasha; Lowe, Jason A; Brown, Sally; Vellinga, Pier; de Gusmão, Diogo; Hinkel, Jochen; Tol, Richard S J

2011-01-13

The range of future climate-induced sea-level rise remains highly uncertain with continued concern that large increases in the twenty-first century cannot be ruled out. The biggest source of uncertainty is the response of the large ice sheets of Greenland and west Antarctica. Based on our analysis, a pragmatic estimate of sea-level rise by 2100, for a temperature rise of 4°C or more over the same time frame, is between 0.5 m and 2 m--the probability of rises at the high end is judged to be very low, but of unquantifiable probability. However, if realized, an indicative analysis shows that the impact potential is severe, with the real risk of the forced displacement of up to 187 million people over the century (up to 2.4% of global population). This is potentially avoidable by widespread upgrade of protection, albeit rather costly with up to 0.02 per cent of global domestic product needed, and much higher in certain nations. The likelihood of protection being successfully implemented varies between regions, and is lowest in small islands, Africa and parts of Asia, and hence these regions are the most likely to see coastal abandonment. To respond to these challenges, a multi-track approach is required, which would also be appropriate if a temperature rise of less than 4°C was expected. Firstly, we should monitor sea level to detect any significant accelerations in the rate of rise in a timely manner. Secondly, we need to improve our understanding of the climate-induced processes that could contribute to rapid sea-level rise, especially the role of the two major ice sheets, to produce better models that quantify the likely future rise more precisely. Finally, responses need to be carefully considered via a combination of climate mitigation to reduce the rise and adaptation for the residual rise in sea level. In particular, long-term strategic adaptation plans for the full range of possible sea-level rise (and other change) need to be widely developed.

Effect of LED and Argon Laser on Degree of Conversion and Temperature Rise of Hybrid and Low Shrinkage Composite Resins

PubMed Central

Pahlevan, Ayob; Tabatabaei, Masumeh Hasani; Arami, Sakineh; Valizadeh, Sara

2016-01-01

Objectives: Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights. Materials and Methods: DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were placed in Teflon molds and cured from the top. The thermocouple under samples recorded the temperature rise. After initial radiation and specimens reaching the ambient temperature, reirradiation was done and temperature was recorded again. Both temperature rise and DC data submitted to one-way ANOVA and Tukey-HSD tests (5% significance). Results: The obtained results revealed that DC was not significantly different between the understudy composite resins or curing units. Low shrinkage composite resin showed a significantly higher temperature rise than hybrid composite resin. Argon laser caused the lowest temperature rise among the curing units. Conclusion: Energy density of light curing units was correlated with the DC. Type of composite resin and light curing unit had a significant effect on temperature rise due to polymerization and curing unit, respectively. PMID:27843507

Effect of LED and Argon Laser on Degree of Conversion and Temperature Rise of Hybrid and Low Shrinkage Composite Resins.

PubMed

Pahlevan, Ayob; Tabatabaei, Masumeh Hasani; Arami, Sakineh; Valizadeh, Sara

2016-01-01

Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights. DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were placed in Teflon molds and cured from the top. The thermocouple under samples recorded the temperature rise. After initial radiation and specimens reaching the ambient temperature, reirradiation was done and temperature was recorded again. Both temperature rise and DC data submitted to one-way ANOVA and Tukey-HSD tests (5% significance). The obtained results revealed that DC was not significantly different between the understudy composite resins or curing units. Low shrinkage composite resin showed a significantly higher temperature rise than hybrid composite resin. Argon laser caused the lowest temperature rise among the curing units. Energy density of light curing units was correlated with the DC. Type of composite resin and light curing unit had a significant effect on temperature rise due to polymerization and curing unit, respectively.

Demonstration of a scalable frequency-domain readout of metallic magnetic calorimeters by means of a microwave SQUID multiplexer

NASA Astrophysics Data System (ADS)

Kempf, Sebastian; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Herrmann, Felix; Papst, Maximilian; Richter, Daniel; Enss, Christian

2017-01-01

We report on the first demonstration of a scalable GHz frequency-domain readout of metallic magnetic calorimeters (MMCs) using a 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The detector array is optimized for detecting soft X-ray photons and the multiplexer is designed to provide a signal rise time τrise<400 ns and an intrinsic energy sensitivity ɛ <30 h . This results in an expected energy resolution Δ EFWHM <10 eV . We measured a signal rise time τrise as low as 90 ns and an energy resolution Δ EFWHM as low as 50 eV for 5.9 keV photons. The rise time is about an order of magnitude faster compared to other multiplexed low-temperature microcalorimeters and close to the intrinsic value set by the coupling between electron and spins. The energy resolution is degraded with respect to our design value due to a rather low intrinsic quality factor of the microwave resonators that is caused by the quality of the Josephson junction of the associated rf-SQUID as well as an elevated chip temperature as compared to the heat bath. Though the achieved energy resolution is not yet compatible with state-of-the-art single-channel MMCs, this demonstration of a scalable readout approach for MMCs in combination with the full understanding of the device performance showing ways how to improve represents an important milestone for the development of future large-scale MMC detector arrays.

Temperature rise induced by some light emitting diode and quartz-tungsten-halogen curing units.

PubMed

Asmussen, Erik; Peutzfeldt, Anne

2005-02-01

Because of the risk of thermal damage to the pulp, the temperature rise induced by light-curing units should not be too high. LED (light emitting diode) curing units have the main part of their irradiation in the blue range and have been reported to generate less heat than QTH (quartz-tungsten-halogen) curing units. This study had two aims: first, to measure the temperature rise induced by ten LED and three QTH curing units; and, second, to relate the measured temperature rise to the power density of the curing units. The light-induced temperature rise was measured by means of a thermocouple embedded in a small cylinder of resin composite. The power density was measured by using a dental radiometer. For LED units, the temperature rise increased with increasing power density, in a statistically significant manner. Two of the three QTH curing units investigated resulted in a higher temperature rise than LED curing units of the same power density. Previous findings, that LED curing units induce less temperature rise than QTH units, does not hold true in general.

Rising Tides: Faculty Expectations of Library Websites

ERIC Educational Resources Information Center

Nicol, Erica Carlson; O'English, Mark

2012-01-01

Looking at 2003-2009 LibQUAL+ responses at research-oriented universities in the United States, faculty library users report a significant and consistent rise in desires and expectations for library-provided online tools and websites, even as student user groups show declining or leveling expectations. While faculty, like students, also report…

Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming.

PubMed

Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

2016-02-26

The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to longevity of animals will become very crucial challenge to biologists of the present millennium.

Climate Change Effects on Respiration Rates of Blue Crab (Callinectes sapidus) from the Patuxent River, Chesapeake Bay

NASA Astrophysics Data System (ADS)

Nyffeler, A.

2016-02-01

A rise in atmospheric CO2 induces a greenhouse effect that also causes ocean temperatures and CO2 levels to rise. These environmental changes may represent an additional energetic cost for blue crabs because they rely on the concentration of CO2 in the water to deposit calcium carbonate in their shells. We conducted a respiration experiment to measure the effect of climate change on crab metabolism. Crabs were collected from the Chesapeake Bay and exposed to different heated and acidified conditions. After crabs had been exposed to the environmental conditions in the chambers for two molts, they were placed in respiration chambers to measure rates of oxygen consumption. Results indicated different trends in respiration rates between the treatments, although the patterns were not statistically significant. Crabs exposed to higher temperatures showed elevated respiration rates, while crabs exposed to high CO2 demonstrated decreased respiration rates. The two factors of climate change (high temperature and high CO2) did not demonstrate the highest respiration rate, but rather the crabs exposed to high temperatures and ambient CO2 showed the highest mean respiration rate. These data suggest that crab metabolism may not change as much as expected due to climate changes.

Dissolved lipid production in the Northern Adriatic (Mediterranean) in response to sea surface warmin

NASA Astrophysics Data System (ADS)

Gasparovic, Blazenka; Novak, Tihana; Godrijan, Jelena; Mlakar, Marina; MAric, Daniela; Djakovac, Tamara

2017-04-01

Marine dissolved organic matter (OM) represents one of the largest active pools of organic carbon in the global carbon cycle. Oceans and seas are responsible for half of global primary production. Ocean warming caused by climate change is already starting to impact the marine life that necessary will have impact on ocean productivity. The partition of OM production by phytoplankton (major OM producer in seas and ocens) in the conditions of rising temperatures may considerably change. This has implications for the export of organic matter from the photic zone. In this study, we set out to see how annual temperature changes between 10 and 30 C in the Northern Adriatic (Mediterranean) affect production of DOM and particularly dissolved lipids and lipid classes. We have sampled at two stations being oligotrophic and mesotrophic where we expected different system reaction to temperature changes. In addition, we performed microcosm incubations covering temperature range of the NA with nutrient amendments to test whether changes in the available nutrients would reflect those of dissolved OM in the NA. We have selected to work with extracellular OM produced during growth of diatom Chaetoceros curvisetus cultures according to the criteria that genera Chaetoceros are important component of the phytoplankton in the NA and are often among bloom-forming taxa. Details on the dissolved lipid and lipid classes production as plankton responce to rising temperature will be discussed.

Recent Warming of Lake Kivu

PubMed Central

Katsev, Sergei; Aaberg, Arthur A.; Crowe, Sean A.; Hecky, Robert E.

2014-01-01

Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730

Recent warming of lake Kivu.

PubMed

Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E

2014-01-01

Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

Coastal sea level rise with warming above 2 °C

PubMed Central

Jevrejeva, Svetlana; Jackson, Luke P.; Riva, Riccardo E. M.; Grinsted, Aslak; Moore, John C.

2016-01-01

Two degrees of global warming above the preindustrial level is widely suggested as an appropriate threshold beyond which climate change risks become unacceptably high. This “2 °C” threshold is likely to be reached between 2040 and 2050 for both Representative Concentration Pathway (RCP) 8.5 and 4.5. Resulting sea level rises will not be globally uniform, due to ocean dynamical processes and changes in gravity associated with water mass redistribution. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 °C goal. By 2040, with a 2 °C warming under the RCP8.5 scenario, more than 90% of coastal areas will experience sea level rise exceeding the global estimate of 0.2 m, with up to 0.4 m expected along the Atlantic coast of North America and Norway. With a 5 °C rise by 2100, sea level will rise rapidly, reaching 0.9 m (median), and 80% of the coastline will exceed the global sea level rise at the 95th percentile upper limit of 1.8 m. Under RCP8.5, by 2100, New York may expect rises of 1.09 m, Guangzhou may expect rises of 0.91 m, and Lagos may expect rises of 0.90 m, with the 95th percentile upper limit of 2.24 m, 1.93 m, and 1.92 m, respectively. The coastal communities of rapidly expanding cities in the developing world, and vulnerable tropical coastal ecosystems, will have a very limited time after midcentury to adapt to sea level rises unprecedented since the dawn of the Bronze Age. PMID:27821743

Coastal sea level rise with warming above 2 °C.

PubMed

Jevrejeva, Svetlana; Jackson, Luke P; Riva, Riccardo E M; Grinsted, Aslak; Moore, John C

2016-11-22

Two degrees of global warming above the preindustrial level is widely suggested as an appropriate threshold beyond which climate change risks become unacceptably high. This "2 °C" threshold is likely to be reached between 2040 and 2050 for both Representative Concentration Pathway (RCP) 8.5 and 4.5. Resulting sea level rises will not be globally uniform, due to ocean dynamical processes and changes in gravity associated with water mass redistribution. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 °C goal. By 2040, with a 2 °C warming under the RCP8.5 scenario, more than 90% of coastal areas will experience sea level rise exceeding the global estimate of 0.2 m, with up to 0.4 m expected along the Atlantic coast of North America and Norway. With a 5 °C rise by 2100, sea level will rise rapidly, reaching 0.9 m (median), and 80% of the coastline will exceed the global sea level rise at the 95th percentile upper limit of 1.8 m. Under RCP8.5, by 2100, New York may expect rises of 1.09 m, Guangzhou may expect rises of 0.91 m, and Lagos may expect rises of 0.90 m, with the 95th percentile upper limit of 2.24 m, 1.93 m, and 1.92 m, respectively. The coastal communities of rapidly expanding cities in the developing world, and vulnerable tropical coastal ecosystems, will have a very limited time after midcentury to adapt to sea level rises unprecedented since the dawn of the Bronze Age.

Estimating Temperature Rise Due to Flashlamp Heating Using Irreversible Temperature Indicators

NASA Technical Reports Server (NTRS)

Koshti, Ajay M.

1999-01-01

One of the nondestructive thermography inspection techniques uses photographic flashlamps. The flashlamps provide a short duration (about 0.005 sec) heat pulse. The short burst of energy results in a momentary rise in the surface temperature of the part. The temperature rise may be detrimental to the top layer of the part being exposed. Therefore, it is necessary to ensure the nondestructive nature of the technique. Amount of the temperature rise determines whether the flashlamp heating would be detrimental to the part. A direct method for the temperature measurement is to use of an infrared pyrometer that has much shorter response time than the flash duration. In this paper, an alternative technique is given using the irreversible temperature 'indicators. This is an indirect technique and it measures the temperature rise on the irreversible temperature indicators and computes the incident heat flux. Once the heat flux is known, the temperature rise on the part can be computed. A wedge shaped irreversible temperature indicator for measuring the heat flux is proposed. A procedure is given to use the wedge indicator.

The lesser known challenge of climate change: thermal variance and sex-reversal in vertebrates with temperature-dependent sex determination.

PubMed

Neuwald, Jennifer L; Valenzuela, Nicole

2011-03-23

Climate change is expected to disrupt biological systems. Particularly susceptible are species with temperature-dependent sex determination (TSD), as in many reptiles. While the potentially devastating effect of rising mean temperatures on sex ratios in TSD species is appreciated, the consequences of increased thermal variance predicted to accompany climate change remain obscure. Surprisingly, no study has tested if the effect of thermal variance around high-temperatures (which are particularly relevant given climate change predictions) has the same or opposite effects as around lower temperatures. Here we show that sex ratios of the painted turtle (Chrysemys picta) were reversed as fluctuations increased around low and high unisexual mean-temperatures. Unexpectedly, the developmental and sexual responses around female-producing temperatures were decoupled in a more complex manner than around male-producing values. Our novel observations are not fully explained by existing ecological models of development and sex determination, and provide strong evidence that thermal fluctuations are critical for shaping the biological outcomes of climate change.

Determination of Temperature Rise and Temperature Differentials of CEMII/B-V Cement for 20MPa Mass Concrete using Adiabatic Temperature Rise Data

NASA Astrophysics Data System (ADS)

Chee Siang, GO

2017-07-01

Experimental test was carried out to determine the temperature rise characteristics of Portland-Fly-Ash Cement (CEM II/B-V, 42.5N) of Blaine fineness 418.6m2/kg and 444.6m2/kg respectively for 20MPa mass concrete under adiabatic condition. The estimation on adiabatic temperature rise by way of CIRIA C660 method (Construction Industry Research & Information Information) was adopted to verify and validate the hot-box test results by simulating the heat generation curve of the concrete under semi-adiabatic condition. Test result found that Portland fly-ash cement has exhibited decrease in the peak value of temperature rise and maximum temperature rise rate. The result showed that the temperature development and distribution profile, which is directly contributed from the heat of hydration of cement with time, is affected by the insulation, initial placing temperature, geometry and size of concrete mass. The mock up data showing the measured temperature differential is significantly lower than the technical specifications 20°C temperature differential requirement and the 27.7°C limiting temperature differential for granite aggregate concrete as stipulated in BS8110-2: 1985. The concrete strength test result revealed that the 28 days cubes compressive strength was above the stipulated 20MPa characteristic strength at 90 days. The test demonstrated that with proper concrete mix design, the use of Portland flyash cement, combination of chilled water and flake ice, and good insulation is effective in reducing peak temperature rise, temperature differential, and lower adiabatic temperature rise for mass concrete pours. As far as the determined adiabatic temperature rise result was concern, the established result could be inferred for in-situ thermal properties of 20MPa mass concrete application, as the result could be repeatable on account of similar type of constituent materials and concrete mix design adopted for permanent works at project site.

Seasonal variations of natural ventilation and radon-222 exhalation in a slightly rising dead-end tunnel.

PubMed

Perrier, Frédéric; Richon, Patrick; Gautam, Umesh; Tiwari, Dilli Ram; Shrestha, Prithvi; Sapkota, Soma Nath

2007-01-01

The concentration activity of radon-222 has been monitored, with some interruptions, from 1997 to 2005 in the end section of a slightly rising, dead-end, 38-m long tunnel located in the Phulchoki hill, near Kathmandu, Nepal. While a high concentration varying from 6 x 10(3) Bq m(-3) to 10 x 10(3) Bq m(-3) is observed from May to September (rainy summer season), the concentration remains at a low level of about 200 Bq m(-3) from October to March (dry winter season). This reduction of radon concentration is associated with natural ventilation of the tunnel, which, contrary to expectations for a rising tunnel, takes place mainly from October to March when the outside air temperature drops below the average tunnel temperature. This interpretation is supported by temperature measurements in the atmosphere of the tunnel, a few meters away from the entrance. The temporal variations of the diurnal amplitude of this temperature indeed follow the ventilation rate deduced from the radon measurements. In the absence of significant ventilation (summer season), the radon exhalation flux at the rock surface into the tunnel atmosphere can be inferred; it exhibits a yearly variation with additional transient reductions associated with heavy rainfall, likely to be due to water infiltration. No effect of atmospheric pressure variations on the radon concentration is observed in this tunnel. This experiment illustrates how small differences in the location and geometry of a tunnel can lead to vastly different behaviours of the radon concentration versus time. This observation has consequences for the estimation of the dose rate and the practicability of radon monitoring for tectonic purposes in underground environments.

Thermal Index Evaluation of Local SAR in MRI-Based Head Models of Adult and Children for Portable Telephones

NASA Astrophysics Data System (ADS)

Fujiwara, Osamu; Miyamoto, Kayoko; Wang, Jianqing

Biological hazards due to radio-frequency (RF) waves result mainly from the temperature rise in tissue. It should be, therefore, clarified to what extent the RF waves of portable telephones increase the temperature-rise in human brain that includes the central part governing the body-temperature regulation function. In this paper, we calculated both the specific absorption rate (SAR) and the resultant temperature-rise for 900 MHz and 2 GHz portable telephones using the finite-difference time-domain (FDTD) method for three typical use positions, i.e., the vertical position, cheek position and tilt position. As a result, we found that there was an increase for median and 1% value of the cumulative distribution of temperature-rise in children’s brains for any use positions of the portable telephones compared to that in the adult’s brain, and also that the increasing trend in children’s brains for temperature-rise is identical to the temperature-rise trend in children’s hypothalamus. In addition, we found that the ten-gram averaged peak SAR among the adult and children heads had the same trend as that of the 0.1% value of the relatively cumulative distribution of temperature-rise, which shows that the ten-gram averaged peak SAR reflects only the localized temperature-rise in the brain surface.

Non-linear and non-local behaviour in spontaneously electrical solids.

PubMed

Roman, M; Taj, S; Gutowski, M; McCoustra, M R S; Dunn, A C; Keolopile, Z G; Rosu-Finsen, A; Cassidy, A M; Field, D

2018-02-14

Using reflection-absorption infrared spectroscopy (RAIRS), we show that solids displaying spontaneous dipole orientation possess quite general non-local and non-linear characteristics, exemplified through their internal electric fields. The most graphic illustration of this, uncovered originally through electron beam studies, may be found in films of cis-methyl formate (cis-MF), for which data demonstrated the counter-intuitive property that the degree of dipole order in the film does not monotonically decrease as the temperature of deposition rises, but rather increases sharply above ∼77 K. Here we show how RAIRS provides independent evidence to support this conclusion. These new data confirm (i) that the behaviour of spontelectrics is governed by an expression for the degree of dipole orientation, which is continuous in temperature, but with a discontinuity in the derivative, and (ii) that the temperature of deposition associated with this discontinuity matches the temperature above which dipole order switches from the expected reduction with temperature to an increase with temperature.

Alterations in gill structure in tropical reef fishes as a result of elevated temperatures

PubMed Central

Bowden, A.J.; Gardiner, N.M.; Couturier, C.S.; Stecyk, J.A.W.; Nilsson, G.E.; Munday, P.L.; Rummer, J.L.

2015-01-01

Tropical regions are expected to be some of the most affected by rising sea surface temperatures (SSTs) because seasonal temperature variations are minimal. As temperatures rise, less oxygen dissolves in water, but metabolic requirements of fish and thus, the demand for effective oxygen uptake, increases. Gill remodelling is an acclimation strategy well documented in freshwater cyprinids experiencing large seasonal variations in temperature and oxygen as well as an amphibious killifish upon air exposure. However, no study has investigated whether tropical reef fishes remodel their gills to allow for increased oxygen demands at elevated temperatures. We tested for gill remodelling in five coral reef species (Acanthochromis polyacanthus, Chromis atripectoralis, Pomacentrus moluccensis, Dascyllus melanurus and Cheilodipterus quinquelineatus) from populations in northern Papua New Guinea (2° 35.765′ S; 150° 46.193′ E). Fishes were acclimated for 12-14 days to 29 and 31 °C, encompassing their seasonal range (29-31 °C), and 33 and 34 °C to account for end-of-century predicted temperatures. We measured lamellar perimeter, cross-sectional area, base thickness, and length for five filaments on the 2nd gill arches and qualitatively assessed 3rd gill arches via scanning electron microscopy (SEM). All species exhibited significant differences in the quantitative measurements made on the lamellae, but no consistent trends with temperature were observed. SEM only revealed alterations in gill morphology in P. moluccensis. The overall lack of changes in gill morphology with increasing temperature suggests that these near-equatorial reef fishes may fail to maintain adequate O2 uptake under future climate scenarios unless other adaptive mechanisms are employed. PMID:24862962

The Climate Science Special Report: Summary of Findings

NASA Astrophysics Data System (ADS)

Wuebbles, D. J.

2017-12-01

As a prelude to the 4th National Climate Assessment, the Climate Science Special Report (CSSR) is being developed to provide a comprehensive assessment of the science underlying the changes occurring in the Earth's climate system, with a special focus on the United States. To summarize some of the findings, the science is clear—the climate on our planet, including the United States, is changing, changing much more rapidly than occurs naturally, and it is happening primarily because of human activities, especially from our use of fossil fuels but also from land use change. Observational evidence for a changing climate abounds, from the top of the atmosphere to the depths of the oceans. Documented changes include surface, atmospheric, and oceanic temperatures; melting glaciers; disappearing snow cover; shrinking sea ice; and rising sea level. Severe weather is becoming more intense. Heatwaves have become more frequent in the United States since the 1960s, while extreme cold temperatures and cold waves are less frequent. Heavy rainfall is increasing in intensity and frequency across the United States and globally. All of these trends are expected to continue. The Earth's climate is projected to continue to change over this century and beyond. Global average sea levels are expected to continue to rise. Many lines of evidence demonstrate that it is extremely likely (95% or greater likelihood) that human activities have been the dominant cause of the observed warming since the mid-20th century. This presentation summarizes key findings from the CSSR.

Temperature rise in ion-leachable cements during setting reaction.

PubMed

Kanchanavasita, W; Pearson, G J; Anstice, H M

1995-11-01

Resin-modified ion-leachable cements have been developed for use as aesthetic restorative materials. Their apparent improved physical and handling properties can make them more attractive for use than conventional glass-ionomers. However, they contain monomers which are known to contract on polymerization and produce a polymerization exotherm. This study evaluated the temperature rise during setting and the rate of dimensional change of several ion-leachable materials. The resin-modified ion-leachable cements demonstrated greater temperature rises and higher rates of contraction than conventional materials. Generally, the behaviour of these resin-modified materials was similar to that of composite resins. However, some resin-modified cements produced a temperature rise of up to 20 degrees C during polymerization which was greater than that of the composite resin. This temperature rise must be taken into account when using the materials in direct contact with dentine in deep cavities without pulp protection. Longer irradiation time than the recommended 20 s did not significantly increase the maximum temperature rise but slightly extended the time before the temperature started to decline. The temperature of the environment had a significant effect on the rate of dimensional change in some materials. The rate of polymerization contraction of light-activated cements was directly related to the observed temperature rise.

Effect of oxygen concentration on fire growth of various types of cable bending in horizontal and vertical orientations

NASA Astrophysics Data System (ADS)

Pangaribuan, Adrianus; Dhiputra, I. M. K.; Nugroho, Yulianto S.

2017-03-01

Electrical cable is a whole of the material including metal (cooper) conductor and its insulation, when an electrical cable is flowed by electric current, based on its own capacity, the temperature of cable conductor increases gradually. If the current flows above the cable carrying capacity, then an extreme temperature rises are expected. When temperature increase, the electric current flow inside cable conductor will decrease gradually related to the resistance and could occur repeatedly in a period. Since electrical faults on electrical cable system are often suspected as the cause of fires, thus this research aims to investigate measures of preventing the fire to start by means of controlling oxygen concentration in a cable compartment. The experimental work was conducted in laboratory by using electrical power cable of 1.5 mm2 size. Two transparent chambers were applied for studying the effect of vertical and horizontal orientations on the cable temperature rise, under various oxygen concentration of the gas streams. In the present work, the electrical was maintained at a constant level during a typical test run. Parametric studies reported in the paper include the use of a bare and insulated cables as well as the bending shape of the cable lines of a straight cable, coiled cable and randomly bent cable which were loaded with the same electric load and oxygen concentration in the gas supply.

Absolute x-ray dosimetry on a synchrotron medical beam line with a graphite calorimeter.

PubMed

Harty, P D; Lye, J E; Ramanathan, G; Butler, D J; Hall, C J; Stevenson, A W; Johnston, P N

2014-05-01

The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and provide confidence in the first implementation of a graphite calorimeter on a synchrotron medical beam line. The graphite calorimeter has a core which rises in temperature when irradiated by the beam. A collimated x-ray beam from the synchrotron with well-defined edges was used to partially irradiate the core. Two filtration sets were used, one corresponding to an average beam energy of about 80 keV, with dose rate about 50 Gy/s, and the second filtration set corresponding to average beam energy of 90 keV, with dose rate about 20 Gy/s. The temperature rise from this beam was measured by a calibrated thermistor embedded in the core which was then converted to absorbed dose to graphite by multiplying the rise in temperature by the specific heat capacity for graphite and the ratio of cross-sectional areas of the core and beam. Conversion of the measured absorbed dose to graphite to absorbed dose to water was achieved using Monte Carlo calculations with the EGSnrc code. The air kerma measurements from the free-air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. Absolute measurements of the IMBL dose rate were made using the graphite calorimeter and compared to measurements with the free-air chamber. The measurements were at three different depths in graphite and two different filtrations. The calorimetry measurements at depths in graphite show agreement within 1% with free-air chamber measurements, when converted to absorbed dose to water. The calorimetry at the surface and free-air chamber results show agreement of order 3% when converted to absorbed dose to water. The combined standard uncertainty is 3.9%. The good agreement of the graphite calorimeter and free-air chamber results indicates that both devices are performing as expected. Further investigations at higher dose rates than 50 Gy/s are planned. At higher dose rates, recombination effects for the free-air chamber are much higher and expected to lead to much larger uncertainties. Since the graphite calorimeter does not have problems associated with dose rate, it is an appropriate primary standard detector for the synchrotron IMBL x rays and is the more accurate dosimeter for the higher dose rates expected in radiotherapy applications.

[Transformer winding's temperature rising and an analysis of its uncertainty].

PubMed

Wang, Pei-Lian; Chen, Yu-En; Zhong, Sheng-Kui

2007-09-01

This paper introduces the temperature rising experimental process and some matters needing attention when the transformer is normally loading. And an analysis of the uncertainty for transformer's temperature rising is also made based on the practical examples' data.

Recent trends in annual snowline variations in the northern wet outer tropics: case studies from southern Cordillera Blanca, Peru

NASA Astrophysics Data System (ADS)

Veettil, Bijeesh Kozhikkodan; Wang, Shanshan; Bremer, Ulisses Franz; de Souza, Sergio Florêncio; Simões, Jefferson Cardia

2017-07-01

This paper describes the changes in the annual maximum snowlines of a selected set of mountain glaciers at the southern end of the Cordillera Blanca between 1984 and 2015 using satellite images. Furthermore, we analysed the existing glacier records in the Cordillera Blanca since the last glacial maximum to understand the evolution of glaciers in this region over a few centuries. There was a rise in the snowline altitude of glaciers in this region since the late 1990s with a few small glacier advances. Historical to the present El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) records were also analysed to understand whether there was a teleconnection between the glacier fluctuations in the region and the phase changes of ENSO and PDO. We also assessed the variations in three important climatic parameters that influence the glacier retreat—temperature, precipitation, and relative humidity—over a few decades. We calculated the anomalies as well as the seasonal changes in these variables since the mid-twentieth century. There was an increase in temperature during this period, and the decrease in precipitation was not so prominent compared with the temperature rise. There was an exceptionally higher increase in relative humidity since the early 2000s, which is relatively higher than that expected due to the observed rate of warming, and this increase in humidity is believed to be the reason behind the unprecedented rise in the snowline altitudes since the beginning of the twenty-first century.

Electrothermal debonding of ceramic brackets. An in vitro study.

PubMed

Brouns, E M; Schopf, P M; Kocjancic, B

1993-04-01

Two different kinds of devices for electrothermal debonding of ceramic brackets are evaluated. Thirty human premolars were bonded with two types of ceramic brackets. Both devices were tested for electrothermal removal of the two bracket types. The pulpal wall temperature increase during electrothermal debonding was recorded in vitro under various circumstances. After debonding, the fracture site was located. The data were compared to the temperature rise after simulated exposure of the teeth to warm beverages. Irreversible pulp damage due to electrothermal debonding of ceramic brackets with both instruments is not to be expected because the obtained results stayed below established primate threshold temperatures and significantly below that of the stimulated control groups. A significant difference was noted when air cooling was initiated during electrothermal debonding. Fracture site location was significantly different in the two ceramic bracket types after electrothermal debonding.

Impact of the 3 °C temperature rise on bacterial growth and carbon transfer towards higher trophic levels: Empirical models for the Adriatic Sea

NASA Astrophysics Data System (ADS)

Šolić, Mladen; Krstulović, Nada; Šantić, Danijela; Šestanović, Stefanija; Kušpilić, Grozdan; Bojanić, Natalia; Ordulj, Marin; Jozić, Slaven; Vrdoljak, Ana

2017-09-01

The Mediterranean Sea (including the Adriatic Sea) has been identified as a 'hotspot' for climate change, with the prediction of the increase in water temperature of 2-4 °C over the next few decades. Being mainly oligotrophic, and strongly phosphorus limited, the Adriatic Sea is characterized by the important role of the microbial food web in production and transfer of biomass and energy towards higher trophic levels. We hypothesized that predicted 3 °C temperature rise in the near future might cause an increase of bacterial production and bacterial losses to grazers, which could significantly enlarge the trophic base for metazoans. This empirical study is based on a combined 'space-for-time substitution' analysis (which is performed on 3583 data sets) and on an experimental approach (36 in situ grazing experiments performed at different temperatures). It showed that the predicted 3 °C temperature increase (which is a result of global warming) in the near future could cause a significant increase in bacterial growth at temperatures lower than 16 °C (during the colder winter-spring period, as well as in the deeper layers). The effect of temperature on bacterial growth could be additionally doubled in conditions without phosphorus limitation. Furthermore, a 3 °C increase in temperature could double the grazing on bacteria by heterotrophic nanoflagellate (HNF) and ciliate predators and it could increase the proportion of bacterial production transferred to the metazoan food web by 42%. Therefore, it is expected that global warming may further strengthen the role of the microbial food web in a carbon cycle in the Adriatic Sea.

In vitro pulp chamber temperature rise from irradiation and exotherm of flowable composites.

PubMed

Baroudi, Kusai; Silikas, Nick; Watts, David C

2009-01-01

The aim of this study was to investigate the pulpal temperature rise induced during the polymerization of flowable and non-flowable composites using light-emitting diode (LED) and halogen (quartz-tungsten-halogen) light-curing units (LCUs). Five flowable and three non-flowable composites were examined. Pulpal temperature changes were recorded over 10 min in a sample primary tooth by a thermocouple. A conventional quartz-tungsten-halogen source and two LEDs, one of which was programmable, were used for light curing the resin composites. Three repetitions per material were made for each LCU. There was a wide range of temperature rises among the materials (P < 0.05). Temperature rises ranged between 1.3 degrees C for Filtek Supreme irradiated by low-power LED and 4.5 degrees C for Grandio Flow irradiated by high-power LED. The highest temperature rises were observed with both the LED high-power and soft-start LCUs. The time to reach the exothermic peak varied significantly between the materials (P < 0.05). Pulpal temperature rise is related to both the radiant energy output from LCUs and the polymerization exotherm of resin composites. A greater potential risk for heat-induced pulp damage might be associated with high-power LED sources. Flowable composites exhibited higher temperature rises than non-flowable materials, because of higher resin contents.

Warming alters community size structure and ecosystem functioning

PubMed Central

Dossena, Matteo; Yvon-Durocher, Gabriel; Grey, Jonathan; Montoya, José M.; Perkins, Daniel M.; Trimmer, Mark; Woodward, Guy

2012-01-01

Global warming can affect all levels of biological complexity, though we currently understand least about its potential impact on communities and ecosystems. At the ecosystem level, warming has the capacity to alter the structure of communities and the rates of key ecosystem processes they mediate. Here we assessed the effects of a 4°C rise in temperature on the size structure and taxonomic composition of benthic communities in aquatic mesocosms, and the rates of detrital decomposition they mediated. Warming had no effect on biodiversity, but altered community size structure in two ways. In spring, warmer systems exhibited steeper size spectra driven by declines in total community biomass and the proportion of large organisms. By contrast, in autumn, warmer systems had shallower size spectra driven by elevated total community biomass and a greater proportion of large organisms. Community-level shifts were mirrored by changes in decomposition rates. Temperature-corrected microbial and macrofaunal decomposition rates reflected the shifts in community structure and were strongly correlated with biomass across mesocosms. Our study demonstrates that the 4°C rise in temperature expected by the end of the century has the potential to alter the structure and functioning of aquatic ecosystems profoundly, as well as the intimate linkages between these levels of ecological organization. PMID:22496185

Flowering phenology shifts in response to biodiversity loss

USGS Publications Warehouse

Wolf, Amelia A.; Zavaleta, Erika S; Selmants, Paul C.

2017-01-01

Observational studies and experimental evidence agree that rising global temperatures have altered plant phenology—the timing of life events, such as flowering, germination, and leaf-out. Other large-scale global environmental changes, such as nitrogen deposition and altered precipitation regimes, have also been linked to changes in flowering times. Despite our increased understanding of how abiotic factors influence plant phenology, we know very little about how biotic interactions can affect flowering times, a significant knowledge gap given ongoing human-caused alteration of biodiversity and plant community structure at the global scale. We experimentally manipulated plant diversity in a California serpentine grassland and found that many plant species flowered earlier in response to reductions in diversity, with peak flowering date advancing an average of 0.6 days per species lost. These changes in phenology were mediated by the effects of plant diversity on soil surface temperature, available soil N, and soil moisture. Peak flowering dates were also more dispersed among species in high-diversity plots than expected based on monocultures. Our findings illustrate that shifts in plant species composition and diversity can alter the timing and distribution of flowering events, and that these changes to phenology are similar in magnitude to effects induced by climate change. Declining diversity could thus contribute to or exacerbate phenological changes attributed to rising global temperatures.

Flowering phenology shifts in response to biodiversity loss.

PubMed

Wolf, Amelia A; Zavaleta, Erika S; Selmants, Paul C

2017-03-28

Observational studies and experimental evidence agree that rising global temperatures have altered plant phenology-the timing of life events, such as flowering, germination, and leaf-out. Other large-scale global environmental changes, such as nitrogen deposition and altered precipitation regimes, have also been linked to changes in flowering times. Despite our increased understanding of how abiotic factors influence plant phenology, we know very little about how biotic interactions can affect flowering times, a significant knowledge gap given ongoing human-caused alteration of biodiversity and plant community structure at the global scale. We experimentally manipulated plant diversity in a California serpentine grassland and found that many plant species flowered earlier in response to reductions in diversity, with peak flowering date advancing an average of 0.6 days per species lost. These changes in phenology were mediated by the effects of plant diversity on soil surface temperature, available soil N, and soil moisture. Peak flowering dates were also more dispersed among species in high-diversity plots than expected based on monocultures. Our findings illustrate that shifts in plant species composition and diversity can alter the timing and distribution of flowering events, and that these changes to phenology are similar in magnitude to effects induced by climate change. Declining diversity could thus contribute to or exacerbate phenological changes attributed to rising global temperatures.

Forage quality declines with rising temperatures, with implications for livestock production and methane emissions

NASA Astrophysics Data System (ADS)

Lee, Mark A.; Davis, Aaron P.; Chagunda, Mizeck G. G.; Manning, Pete

2017-03-01

Livestock numbers are increasing to supply the growing demand for meat-rich diets. The sustainability of this trend has been questioned, and future environmental changes, such as climate change, may cause some regions to become less suitable for livestock. Livestock and wild herbivores are strongly dependent on the nutritional chemistry of forage plants. Nutrition is positively linked to weight gains, milk production and reproductive success, and nutrition is also a key determinant of enteric methane production. In this meta-analysis, we assessed the effects of growing conditions on forage quality by compiling published measurements of grass nutritive value and combining these data with climatic, edaphic and management information. We found that forage nutritive value was reduced at higher temperatures and increased by nitrogen fertiliser addition, likely driven by a combination of changes to species identity and changes to physiology and phenology. These relationships were combined with multiple published empirical models to estimate forage- and temperature-driven changes to cattle enteric methane production. This suggested a previously undescribed positive climate change feedback, where elevated temperatures reduce grass nutritive value and correspondingly may increase methane production by 0.9 % with a 1 °C temperature rise and 4.5 % with a 5 °C rise (model average), thus creating an additional climate forcing effect. Future methane production increases are expected to be largest in parts of North America, central and eastern Europe and Asia, with the geographical extent of hotspots increasing under a high emissions scenario. These estimates require refinement and a greater knowledge of the abundance, size, feeding regime and location of cattle, and the representation of heat stress should be included in future modelling work. However, our results indicate that the cultivation of more nutritious forage plants and reduced livestock farming in warming regions may reduce this additional source of pastoral greenhouse gas emissions.

Future habitat suitability for coral reef ecosystems under global warming and ocean acidification

PubMed Central

Couce, Elena; Ridgwell, Andy; Hendy, Erica J

2013-01-01

Rising atmospheric CO2 concentrations are placing spatially divergent stresses on the world's tropical coral reefs through increasing ocean surface temperatures and ocean acidification. We show how these two stressors combine to alter the global habitat suitability for shallow coral reef ecosystems, using statistical Bioclimatic Envelope Models rather than basing projections on any a priori assumptions of physiological tolerances or fixed thresholds. We apply two different modeling approaches (Maximum Entropy and Boosted Regression Trees) with two levels of complexity (one a simplified and reduced environmental variable version of the other). Our models project a marked temperature-driven decline in habitat suitability for many of the most significant and bio-diverse tropical coral regions, particularly in the central Indo-Pacific. This is accompanied by a temperature-driven poleward range expansion of favorable conditions accelerating up to 40–70 km per decade by 2070. We find that ocean acidification is less influential for determining future habitat suitability than warming, and its deleterious effects are centered evenly in both hemispheres between 5° and 20° latitude. Contrary to expectations, the combined impact of ocean surface temperature rise and acidification leads to little, if any, degradation in future habitat suitability across much of the Atlantic and areas currently considered ‘marginal’ for tropical corals, such as the eastern Equatorial Pacific. These results are consistent with fossil evidence of range expansions during past warm periods. In addition, the simplified models are particularly sensitive to short-term temperature variations and their projections correlate well with reported locations of bleaching events. Our approach offers new insights into the relative impact of two global environmental pressures associated with rising atmospheric CO2 on potential future habitats, but greater understanding of past and current controls on coral reef ecosystems is essential to their conservation and management under a changing climate. PMID:23893550

Future habitat suitability for coral reef ecosystems under global warming and ocean acidification.

PubMed

Couce, Elena; Ridgwell, Andy; Hendy, Erica J

2013-12-01

Rising atmospheric CO2 concentrations are placing spatially divergent stresses on the world's tropical coral reefs through increasing ocean surface temperatures and ocean acidification. We show how these two stressors combine to alter the global habitat suitability for shallow coral reef ecosystems, using statistical Bioclimatic Envelope Models rather than basing projections on any a priori assumptions of physiological tolerances or fixed thresholds. We apply two different modeling approaches (Maximum Entropy and Boosted Regression Trees) with two levels of complexity (one a simplified and reduced environmental variable version of the other). Our models project a marked temperature-driven decline in habitat suitability for many of the most significant and bio-diverse tropical coral regions, particularly in the central Indo-Pacific. This is accompanied by a temperature-driven poleward range expansion of favorable conditions accelerating up to 40-70 km per decade by 2070. We find that ocean acidification is less influential for determining future habitat suitability than warming, and its deleterious effects are centered evenly in both hemispheres between 5° and 20° latitude. Contrary to expectations, the combined impact of ocean surface temperature rise and acidification leads to little, if any, degradation in future habitat suitability across much of the Atlantic and areas currently considered 'marginal' for tropical corals, such as the eastern Equatorial Pacific. These results are consistent with fossil evidence of range expansions during past warm periods. In addition, the simplified models are particularly sensitive to short-term temperature variations and their projections correlate well with reported locations of bleaching events. Our approach offers new insights into the relative impact of two global environmental pressures associated with rising atmospheric CO2 on potential future habitats, but greater understanding of past and current controls on coral reef ecosystems is essential to their conservation and management under a changing climate. © 2013 John Wiley & Sons Ltd.

Atlantic hurricane surge response to geoengineering.

PubMed

Moore, John C; Grinsted, Aslak; Guo, Xiaoran; Yu, Xiaoyong; Jevrejeva, Svetlana; Rinke, Annette; Cui, Xuefeng; Kravitz, Ben; Lenton, Andrew; Watanabe, Shingo; Ji, Duoying

2015-11-10

Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges.

Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

PubMed Central

Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

2016-01-01

The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to longevity of animals will become very crucial challenge to biologists of the present millennium. PMID:26981200

Finite difference modelling of the temperature rise in non-linear medical ultrasound fields.

PubMed

Divall, S A; Humphrey, V F

2000-03-01

Non-linear propagation of ultrasound can lead to increased heat generation in medical diagnostic imaging due to the preferential absorption of harmonics of the original frequency. A numerical model has been developed and tested that is capable of predicting the temperature rise due to a high amplitude ultrasound field. The acoustic field is modelled using a numerical solution to the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, known as the Bergen Code, which is implemented in cylindrical symmetric form. A finite difference representation of the thermal equations is used to calculate the resulting temperature rises. The model allows for the inclusion of a number of layers of tissue with different acoustic and thermal properties and accounts for the effects of non-linear propagation, direct heating by the transducer, thermal diffusion and perfusion in different tissues. The effect of temperature-dependent skin perfusion and variation in background temperature between the skin and deeper layers of the body are included. The model has been tested against analytic solutions for simple configurations and then used to estimate temperature rises in realistic obstetric situations. A pulsed 3 MHz transducer operating with an average acoustic power of 200 mW leads to a maximum steady state temperature rise inside the foetus of 1.25 degrees C compared with a 0.6 degree C rise for the same transmitted power under linear propagation conditions. The largest temperature rise occurs at the skin surface, with the temperature rise at the foetus limited to less than 2 degrees C for the range of conditions considered.

Vulnerability to changes in malaria transmission due to climate change in West Africa

NASA Astrophysics Data System (ADS)

Yamana, T. K.; Eltahir, E. A.

2012-12-01

Malaria transmission in West Africa is strongly tied to climate; temperature affects the development rate of the malaria parasite, as well as the survival of the mosquitoes that transmit the disease, and rainfall is tied to mosquito abundance, as the vector lays its eggs in rain-fed water pools. As a result, the environmental suitability for malaria transmission in this region is expected to change as temperatures rise and rainfall patterns are altered. The vulnerability to changes in transmission varies throughout West Africa. Areas where malaria prevalence is already very high will be less sensitive to changes in transmission. Increases in environmental suitability for malaria transmission in the most arid regions may still be insufficient to allow sustained transmission. However, areas were malaria transmission currently occurs at low levels are expected to be the most sensitive to changes in environmental suitability for transmission. Here, we use data on current environment and malaria transmission rates to highlight areas in West Africa that we expect to be most vulnerable to an increase in malaria under certain climate conditions. We then analyze climate predictions from global climate models in vulnerable areas, and make predictions for the expected change in environmental suitability for malaria transmission using the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a mechanistic model developed to simulate village-scale response of malaria transmission to environmental variables in West Africa.

Quantifying the sources of uncertainty in an ensemble of hydrological climate-impact projections

NASA Astrophysics Data System (ADS)

Aryal, Anil; Shrestha, Sangam; Babel, Mukand S.

2018-01-01

The objective of this paper is to quantify the various sources of uncertainty in the assessment of climate change impact on hydrology in the Tamakoshi River Basin, located in the north-eastern part of Nepal. Multiple climate and hydrological models were used to simulate future climate conditions and discharge in the basin. The simulated results of future climate and river discharge were analysed for the quantification of sources of uncertainty using two-way and three-way ANOVA. The results showed that temperature and precipitation in the study area are projected to change in near- (2010-2039), mid- (2040-2069) and far-future (2070-2099) periods. Maximum temperature is likely to rise by 1.75 °C under Representative Concentration Pathway (RCP) 4.5 and by 3.52 °C under RCP 8.5. Similarly, the minimum temperature is expected to rise by 2.10 °C under RCP 4.5 and by 3.73 °C under RCP 8.5 by the end of the twenty-first century. Similarly, the precipitation in the study area is expected to change by - 2.15% under RCP 4.5 and - 2.44% under RCP 8.5 scenarios. The future discharge in the study area was projected using two hydrological models, viz. Soil and Water Assessment Tool (SWAT) and Hydrologic Engineering Center's Hydrologic Modelling System (HEC-HMS). The SWAT model projected discharge is expected to change by small amount, whereas HEC-HMS model projected considerably lower discharge in future compared to the baseline period. The results also show that future climate variables and river hydrology contain uncertainty due to the choice of climate models, RCP scenarios, bias correction methods and hydrological models. During wet days, more uncertainty is observed due to the use of different climate models, whereas during dry days, the use of different hydrological models has a greater effect on uncertainty. Inter-comparison of the impacts of different climate models reveals that the REMO climate model shows higher uncertainty in the prediction of precipitation and, consequently, in the prediction of future discharge and maximum probable flood.

In Brief: Report predicts 57% growth in world energy use by 2030

NASA Astrophysics Data System (ADS)

Zielinski, Sarah

2007-06-01

Energy demand is expected to grow rapidly in the next decades, with world energy use rising by 57% by 2030, compared with 2004 levels, according to a new report from the U.S. Energy Information Administration. Much of this growth is expected outside of developed countries within the Organization for Economic Cooperation and Development; these non-OECD countries will account for about 95% of the projected growth. Although rising oil prices are expected to dampen growth in this sector, their consumption is expected to reach 118 million barrels per day in 2030, 35 million barrels per day more than in 2004. Overall nuclear energy capacity will rise from 368 gigawatts in 2004 to 481 gigawatts in 2030, but declines are projected in several European countries that are planning to phase out the use of nuclear power. Renewable sources of energy are expected to rise at a rate of about 1.9 percent per year, with much of the growth coming from hydroelectric facilities in non-OECD countries in Asia and Central and South America. The report, ``International Energy Outlook 2007,'' is available at http://www.eia.doe.gov/oiaf/ieo/

Temperature mediated moose survival in Northeastern Minnesota

USGS Publications Warehouse

Lenarz, M.S.; Nelson, M.E.; Schrage, M.W.; Edwards, A.J.

2009-01-01

The earth is in the midst of a pronounced warming trend and temperatures in Minnesota, USA, as elsewhere, are projected to increase. Northern Minnesota represents the southern edge to the circumpolar distribution of moose (Alces alces), a species intolerant of heat. Moose increase their metabolic rate to regulate their core body temperature as temperatures rise. We hypothesized that moose survival rates would be a function of the frequency and magnitude that ambient temperatures exceeded the upper critical temperature of moose. We compared annual and seasonal moose survival in northeastern Minnesota between 2002 and 2008 with a temperature metric. We found that models based on January temperatures above the critical threshold were inversely correlated with subsequent survival and explained >78 of variability in spring, fall, and annual survival. Models based on late-spring temperatures also explained a high proportion of survival during the subsequent fall. A model based on warm-season temperatures was important in explaining survival during the subsequent winter. Our analyses suggest that temperatures may have a cumulative influence on survival. We expect that continuation or acceleration of current climate trends will result in decreased survival, a decrease in moose density, and ultimately, a retreat of moose northward from their current distribution.

In-Bed Accountability Development for a Passively Cooled, Electrically Heated Hydride (PACE) Bed

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

Klein, J.E.

A nominal 1500 STP-L PAssively Cooled, Electrically heated hydride (PACE) Bed has been developed for implementation into a new Savannah River Site tritium project. The 1.2 meter (four-foot) long process vessel contains on internal 'U-tube' for tritium In-Bed Accountability (IBA) measurements. IBA will be performed on six, 12.6 kg production metal hydride storage beds.IBA tests were done on a prototype bed using electric heaters to simulate the radiolytic decay of tritium. Tests had gas flows from 10 to 100 SLPM through the U-tube or 100 SLPM through the bed's vacuum jacket. IBA inventory measurement errors at the 95% confidence levelmore » were calculated using the correlation of IBA gas temperature rise, or (hydride) bed temperature rise above ambient temperature, versus simulated tritium inventory.Prototype bed IBA inventory errors at 100 SLPM were the largest for gas flows through the vacuum jacket: 15.2 grams for the bed temperature rise and 11.5 grams for the gas temperature rise. For a 100 SLPM U-tube flow, the inventory error was 2.5 grams using bed temperature rise and 1.6 grams using gas temperature rise. For 50 to 100 SLPM U-tube flows, the IBA gas temperature rise inventory errors were nominally one to two grams that increased above four grams for flows less than 50 SLPM. For 50 to 100 SLPM U-tube flows, the IBA bed temperature rise inventory errors were greater than the gas temperature rise errors, but similar errors were found for both methods at gas flows of 20, 30, and 40 SLPM.Electric heater IBA tests were done for six production hydride beds using a 45 SLPM U-tube gas flow. Of the duplicate runs performed on these beds, five of the six beds produced IBA inventory errors of approximately three grams: consistent with results obtained in the laboratory prototype tests.« less

In-Bed Accountability Development for a Passively Cooled, Electrically Heated Hydride (PACE) Bed

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

KLEIN, JAMES

A nominal 1500 STP-L PAssively Cooled, Electrically heated hydride (PACE) Bed has been developed for implementation into a new Savannah River Site tritium project. The 1.2 meter (four-foot) long process vessel contains an internal ''U-tube'' for tritium In-Bed Accountability (IBA) measurements. IBA will be performed on six, 12.6 kg production metal hydride storage beds. IBA tests were done on a prototype bed using electric heaters to simulate the radiolytic decay of tritium. Tests had gas flows from 10 to 100 SLPM through the U-tube or 100 SLPM through the bed's vacuum jacket. IBA inventory measurement errors at the 95 percentmore » confidence level were calculated using the correlation of IBA gas temperature rise, or (hydride) bed temperature rise above ambient temperature, versus simulated tritium inventory. Prototype bed IBA inventory errors at 100 SLPM were the largest for gas flows through the vacuum jacket: 15.2 grams for the bed temperature rise and 11.5 grams for the gas temperature rise. For a 100 SLPM U-tube flow, the inventory error was 2.5 grams using bed temperature rise and 1.6 grams using gas temperature rise. For 50 to 100 SLPM U-tube flows, the IBA gas temperature rise inventory errors were nominally one to two grams that increased above four grams for flows less than 50 SLPM. For 50 to 100 SLPM U-tube flows, the IBA bed temperature rise inventory errors were greater than the gas temperature rise errors, but similar errors were found for both methods at gas flows of 20, 30, and 40 SLPM. Electric heater IBA tests were done for six production hydride beds using a 45 SLPM U-tube gas flow. Of the duplicate runs performed on these beds, five of the six beds produced IBA inventory errors of approximately three grams: consistent with results obtained in the laboratory prototype tests.« less

A new model for the estimation of time of death from vitreous potassium levels corrected for age and temperature.

PubMed

Zilg, B; Bernard, S; Alkass, K; Berg, S; Druid, H

2015-09-01

Analysis of potassium concentration in the vitreous fluid of the eye is frequently used by forensic pathologists to estimate the postmortem interval (PMI), particularly when other methods commonly used in the early phase of an investigation can no longer be applied. The postmortem rise in vitreous potassium has been recognized for several decades and is readily explained by a diffusion of potassium from surrounding cells into the vitreous fluid. However, there is no consensus regarding the mathematical equation that best describes this increase. The existing models assume a linear increase, but different slopes and starting points have been proposed. In this study, vitreous potassium levels, and a number of factors that may influence these levels, were examined in 462 cases with known postmortem intervals that ranged from 2h to 17 days. We found that the postmortem rise in potassium followed a non-linear curve and that decedent age and ambient temperature influenced the variability by 16% and 5%, respectively. A long duration of agony and a high alcohol level at the time of death contributed less than 1% variability, and evaluation of additional possible factors revealed no detectable impact on the rise of vitreous potassium. Two equations were subsequently generated, one that represents the best fit of the potassium concentrations alone, and a second that represents potassium concentrations with correction for decedent age and/or ambient temperature. The former was associated with narrow confidence intervals in the early postmortem phase, but the intervals gradually increased with longer PMIs. For the latter equation, the confidence intervals were reduced at all PMIs. Therefore, the model that best describes the observed postmortem rise in vitreous potassium levels includes potassium concentration, decedent age, and ambient temperature. Furthermore, the precision of these equations, particularly for long PMIs, is expected to gradually improve by adjusting the constants as more reference data are added over time. A web application that facilitates this calculation process and allows for such future modifications has been developed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

C-14 and temperature variation around and after AD 775 - after the Dark Age Grand Minimum

NASA Astrophysics Data System (ADS)

Neuhäuser, Ralph; Neuhäuser, Dagmar L.

2016-04-01

We have compiled an extensive catalog of aurora observations from the Far and Near East as well as Europe for the time from AD 550 to 845. From historic observations of aurorae and sunspots as well as the C-14 and Be-10 data, we can date the end of the Dark Age grand minimum to about AD 690; we see strong activity after this period. We can fix the solar activity Schwabe cycle maxima and minima in the 7th and 8th centuries.. The strong 14-C increase in data with 1-yr time resolution in the AD 770s (e.g. Miyake et al. 2012) is still a matter of debate, e.g. a solar super-flare. In the last three millennia, there were two more strong rapid rises in 14-C - around BC 671 and AD 1795. All three 14-C variations are embedded in similar evolution of solar activity, as we can show with various solar activity proxies; secular evolution of solar wind plays an important role. The rises of 14-C - within a few years each - can be explained by a sudden strong decrease in solar modulation potential leading to increased radioisotope production. The strong rises around AD 775 and 1795 are due to three effects: (i) very strong activity in the previous cycles (i.e. very low 14-C level), (ii) the declining phase of a very strong Schwabe cycle, and (iii) a phase of very weak activity after the strong 14-C rise - very short and/or weak cycle(s) like the suddenly starting Dalton minimum. In addition to arXiv:1503.01581 and arXiv:1508.06745, we also discuss the temperature depression and new quasi-annual 10-Be data. If a temperature depression right after AD 775 for a few decades can be confirmed, this would be fully consistent with our suggestion: reduced solar activity since AD 775 (for a few decades like in the Dalton minimum). Otherwise, one would not expect such a temperature depression after a solar super-flare.

Thresholds for Coral Bleaching: Are Synergistic Factors and Shifting Thresholds Changing the Landscape for Management? (Invited)

NASA Astrophysics Data System (ADS)

Eakin, C.; Donner, S. D.; Logan, C. A.; Gledhill, D. K.; Liu, G.; Heron, S. F.; Christensen, T.; Rauenzahn, J.; Morgan, J.; Parker, B. A.; Hoegh-Guldberg, O.; Skirving, W. J.; Strong, A. E.

2010-12-01

As carbon dioxide rises in the atmosphere, climate change and ocean acidification are modifying important physical and chemical parameters in the oceans with resulting impacts on coral reef ecosystems. Rising CO2 is warming the world’s oceans and causing corals to bleach, with both alarming frequency and severity. The frequent return of stressful temperatures has already resulted in major damage to many of the world’s coral reefs and is expected to continue in the foreseeable future. Warmer oceans also have contributed to a rise in coral infectious diseases. Both bleaching and infectious disease can result in coral mortality and threaten one of the most diverse ecosystems on Earth and the important ecosystem services they provide. Additionally, ocean acidification from rising CO2 is reducing the availability of carbonate ions needed by corals to build their skeletons and perhaps depressing the threshold for bleaching. While thresholds vary among species and locations, it is clear that corals around the world are already experiencing anomalous temperatures that are too high, too often, and that warming is exceeding the rate at which corals can adapt. This is despite a complex adaptive capacity that involves both the coral host and the zooxanthellae, including changes in the relative abundance of the latter in their coral hosts. The safe upper limit for atmospheric CO2 is probably somewhere below 350ppm, a level we passed decades ago, and for temperature is a sustained global temperature increase of less than 1.5°C above pre-industrial levels. How much can corals acclimate and/or adapt to the unprecedented fast changing environmental conditions? Any change in the threshold for coral bleaching as the result of acclimation and/or adaption may help corals to survive in the future but adaptation to one stress may be maladaptive to another. There also is evidence that ocean acidification and nutrient enrichment modify this threshold. What do shifting thresholds mean for identifying limits and taking management actions to adapt to climate change?

Cluster observations of EMIC triggered emissions in association with Pc1 waves near Earth's plasmapause

NASA Astrophysics Data System (ADS)

Pickett, J. S.; Grison, B.; Omura, Y.; Engebretson, M. J.; Dandouras, I.; Masson, A.; Adrian, M. L.; Santolík, O.; Décréau, P. M. E.; Cornilleau-Wehrlin, N.; Constantinescu, D.

2010-05-01

The Cluster spacecraft were favorably positioned on the nightside near the equatorial plasmapause of Earth at L ˜ 4.3 on 30 March 2002 to observe electromagnetic ion cyclotron (EMIC) rising tone emissions in association with Pc1 waves at 1.5 Hz. The EMIC rising tone emissions were found to be left-hand, circularly polarized, dispersive, and propagating away from the equator. Their burstiness and dispersion of ˜30s/Hz rising out of the 1.5 Hz Pc1 waves are consistent with their identification as EMIC triggered chorus emissions, the first to be reported through in situ observations near the plasmapause. Along with the expected H+ ring current ions seen at higher energies (>300 eV), lower energy ions (300 eV and less) were observed during the most intense EMIC triggered emission events. Nonlinear wave-particle interactions via cyclotron resonance between the ˜2-10 keV H+ ions with temperature anisotropy and the linearly-amplified Pc1 waves are suggested as a possible generation mechanism for the EMIC triggered emissions.

Beyond just sea-level rise: Considering macroclimatic drivers within coastal wetland vulnerability assessments to climate change

USGS Publications Warehouse

Osland, Michael J.; Enwright, Nicholas M.; Day, Richard H.; Gabler, Christopher A.; Stagg, Camille L.; Grace, James B.

2016-01-01

Due to their position at the land-sea interface, coastal wetlands are vulnerable to many aspects of climate change. However, climate change vulnerability assessments for coastal wetlands generally focus solely on sea-level rise without considering the effects of other facets of climate change. Across the globe and in all ecosystems, macroclimatic drivers (e.g., temperature and rainfall regimes) greatly influence ecosystem structure and function. Macroclimatic drivers have been the focus of climate-change related threat evaluations for terrestrial ecosystems, but largely ignored for coastal wetlands. In some coastal wetlands, changing macroclimatic conditions are expected to result in foundation plant species replacement, which would affect the supply of certain ecosystem goods and services and could affect ecosystem resilience. As examples, we highlight several ecological transition zones where small changes in macroclimatic conditions would result in comparatively large changes in coastal wetland ecosystem structure and function. Our intent in this communication is not to minimize the importance of sea-level rise. Rather, our overarching aim is to illustrate the need to also consider macroclimatic drivers within vulnerability assessments for coastal wetlands.

Temperature rises during application of Er:YAG laser under different primary dentin thicknesses.

PubMed

Hubbezoglu, Ihsan; Unal, Murat; Zan, Recai; Hurmuzlu, Feridun

2013-05-01

The present study investigated the effects of the Er:YAG laser's different pulse repetition rates on temperature rise under various primary dentin thicknesses. The Er:YAG laser can be used for restorative approaches in clinics and is used to treat dental caries. There are some reports that explain the temperature rise effect of the Er:YAG laser. Recently, the Er:YAG laser has been found to play an important role in temperature rises during the application on dentin. Caries-free primary mandibular molars were prepared to obtain dentin discs with 0.5, 1, 1.5, and 2 mm thicknesses (n=10). These discs were placed between the Teflon mold cylinders of a temperature test apparatus. We preferred three pulse repetition rates of 10, 15, and 20 Hz with an energy density of 12.7 J/cm2 and a 230 μs pulse duration. All dentin discs were irradiated for 30 sec by the Er:YAG laser. Temperature rises were recorded using an L-type thermocouple and universal data loggers/scanners (E-680, Elimko Co., Turkey). Data were analyzed by two-way ANOVA and Tukey tests. Whereas the lowest temperature rise (0.44±0.09 °C) was measured from a 10 Hz pulse repetition rate at a dentin thickness of 2 mm, the highest temperature rise (3.86±0.43 °C) was measured from a 20 Hz pulse repetition rate at a 0.5 mm dentin thickness. Temperature rise did not reach critical value for pulpal injury in any primary dentin thicknesses irradiated by a high repetition rate of the Er:YAG laser.

46 CFR 116.415 - Fire control boundaries.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the applicable time period listed below, the average temperature on the unexposed side does not rise..., including any joint, rise more than 181 °C (325 °F) above the original temperature: A-60 Class 60 minutes A... that it will withstand the same temperature rise limits as the boundary penetrated. (iii) B-Class...

The influence of photosynthetic acclimation to rising CO2 and warmer temperatures on leaf and canopy photosynthesis models

USDA-ARS?s Scientific Manuscript database

There is an increasing necessity to understand how climate change factors, particularly increasing atmospheric concentrations of CO2 ([CO2]) and rising temperature, will influence photosynthetic carbon assimilation (A). Based on theory, an increased [CO2] concomitant with a rise in temperature will ...

Thulium fibre laser nerve stimulation and its application in human pain research

NASA Astrophysics Data System (ADS)

Warnaby, Catherine E.

Experimental pain induction, in combination with psychophysical and functional imaging techniques, allows the controlled study of the mechanisms, pathways and brain areas involved in the processing of noxious stimuli. Laser nerve stimulation provides an excellent stimulus that selectively activates the Adelta and C nociceptors with only low concurrent activity in the warmth system. Thulium fibre laser systems, operating near 2mum, offer several advantages over other pain stimulators including the CO[2] and Tm:YAG laser systems. These advantages include direct absorption at the location of the nociceptors, reduced likelihood of tissue damage, improved compatibility with fMRI, and wavelength tunability. The main aims of the thesis were to apply an initial thulium fibre laser system to pain activation studies in healthy subjects and confirm the potential advantages. A 1D finite difference photothermal model confirmed that thulium fibre laser radiation is absorbed throughout the expected location of the nociceptors and produces a lower surface temperature than CO[2] radiation. In order to produce a temperature rise of 9°C at 150mum, thulium radiation induces a surface temperature rise of 12°C compared to 21°C surface temperature rise using CO[2] radiation. The use of thulium fibre radiation greatly reduces the likelihood of tissue damage and first-degree burns when compared to CO[2] radiation. The spatial temperature gradient and the surface temperature rise were also found to be strongly dependent on the thulium fibre laser emission wavelength, which implies that wavelength tuning may be used to obtain the optimum stimulus wavelength in the 2mum region. The 5W initial fibre laser system was fully characterised before application to human pain studies and was shown to have excellent reproducibility of the stimulus parameters, with short-term and long-term deviations of the pulse energy of 5% and 8% of the mean respectively. The thulium fibre laser emits radiation over a 38nm wavelength range from 2.006-2.044mum. The initial system was used successfully to elicit painful sensations and laser evoked potentials (LEPs), which showed the expected dependence on the laser stimulus parameters. In agreement with the modelled results, beam diameters from 5-8mm for a 150ms pulse duration were found to elicit painful responses while minimising tissue damage. Psychophysical assessment of the pain threshold energy and energy density in ten volunteers, using the modified staircase technique and the method of constant stimuli, also showed the expected dependence on the laser beam diameter over this range. The topographical distribution of the LEPs elicited by the thulium fibre laser and a CO[2] pain stimulator were found to be very similar. However, statistically significant differences in the peak latencies of the LEP components were observed. The peak latency of the N2, P2 and P3 components elicited by the thulium fibre laser were found to be longer by 44ms, 52ms and 78ms respectively than those elicited by the CO[2] laser across five volunteers. These latency differences are believed to be due to the difference in beam diameter of the two stimuli, which produces an increase in local spatial summation for the CO[2] laser stimuli. The effectiveness of the thulium fibre laser as a controlled pain stimulator for human pain research has been confirmed. Using the current thulium fibre laser stimulation system, the optimum stimulus parameters are provided by a beam diameter of 6mm and a pulse duration of 150ms. However, further application of the current system to human pain research is limited by the available output power and the delivery of the thulium radiation to the subject. Suggestions are made for further work using an improved thulium fibre laser system with an increased output power of 20W, optical fibre delivery and wavelength tuning.

Climate variability, vulnerability, and coping mechanism in Alaknanda catchment, Central Himalaya, India.

PubMed

Kumar, Kireet; Joshi, Sneh; Joshi, Varun

2008-06-01

A study was carried out to discover trends in the rainfall and temperature pattern of the Alaknanda catchment in the Central Himalaya. Data on the annual rainfall, monsoon rainfall for the last decade, and average annual temperatures over the last few decades were analyzed. Nonparametric methods (Mann-Kendall and Sen's method) were employed to identify trends. The Mann-Kendall test shows a decline in rainfall and rise in temperature, and these trends were found to be statistically significant at the 95% confidence level for both transects. Sen's method also confirms this trend. This aspect has to be considered seriously for the simple reason that if the same trend continues in the future, more chances of drought are expected. The impact of climate change has been well perceived by the people of the catchment, and a coping mechanism has been developed at the local level.

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

Keyser, Matthew A

Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell, the efficiencies of power and energy cells, and what type ofmore » battery thermal management solutions are available in today's market. Thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.« less

Future heat waves due to climate change threaten the survival of Posidonia oceanica seedlings.

PubMed

Guerrero-Meseguer, Laura; Marín, Arnaldo; Sanz-Lázaro, Carlos

2017-11-01

Extreme weather events are major drivers of ecological change, and their occurrence is likely to increase due to climate change. The transient increases in atmospheric temperatures are leading to a greater occurrence of heat waves, extreme events that can produce a substantial warming of water, especially in enclosed basins such as the Mediterranean Sea. Here, we tested the effects of current and predicted heat waves on the early stages of development of the seagrass Posidonia oceanica. Temperatures above 27 °C limited the growth of the plant by inhibiting its photosynthetic system. It suffered a reduction in leaf growth and faster leaf senescence, and in some cases mortality. This study demonstrates that the greater frequency of heat waves, along with anticipated temperature rises in coming decades, are expected to negatively affect the germination of P. oceanica seedlings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enabling fast charging - Battery thermal considerations

NASA Astrophysics Data System (ADS)

Keyser, Matthew; Pesaran, Ahmad; Li, Qibo; Santhanagopalan, Shriram; Smith, Kandler; Wood, Eric; Ahmed, Shabbir; Bloom, Ira; Dufek, Eric; Shirk, Matthew; Meintz, Andrew; Kreuzer, Cory; Michelbacher, Christopher; Burnham, Andrew; Stephens, Thomas; Francfort, James; Carlson, Barney; Zhang, Jiucai; Vijayagopal, Ram; Hardy, Keith; Dias, Fernando; Mohanpurkar, Manish; Scoffield, Don; Jansen, Andrew N.; Tanim, Tanvir; Markel, Anthony

2017-11-01

Battery thermal barriers are reviewed with regards to extreme fast charging. Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell, the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today's market. Thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.

Experimental system for in-situ measurement of temperature rise in animal tissue under exposure to acoustic radiation force impulse.

PubMed

Nitta, Naotaka; Ishiguro, Yasunao; Sasanuma, Hideki; Taniguchi, Nobuyuki; Akiyama, Iwaki

2015-01-01

Acoustic radiation force impulse (ARFI) has recently been used for tissue elasticity measurement and imaging. On the other hand, it is predicted that a rise in temperature occurs. In-situ measurement of temperature rise in animal experiments is important, yet measurement using thermocouples has some problems such as position mismatch of the temperature measuring junction of the thermocouple and the focal point of ultrasound. Therefore, an in-situ measurement system for solving the above problems was developed in this study. The developed system is composed mainly of an ultrasound irradiation unit including a custom-made focused transducer with a through hole for inserting a thin-wire thermocouple, and a temperature measurement unit including the thermocouple. The feasibility of the developed system was evaluated by means of experiments using a tissue-mimicking material (TMM), a TMM containing a bone model or a chicken bone, and an extracted porcine liver. The similarity between the experimental results and the results of simulation using a finite element method (FEM) implied the reasonableness of in-situ temperature rise measured by the developed system. The developed system will become a useful tool for measuring in-situ temperature rise in animal experiments and obtaining findings with respect to the relationship between ultrasound irradiation conditions and in-situ temperature rise.

Quantifying the Influence of Climate on Human Conflict

NASA Astrophysics Data System (ADS)

Hsiang, S. M.; Burke, M.; Miguel, E.

2014-12-01

A rapidly growing body of research examines whether human conflict can be affected by climatic changes. Drawing from archaeology, criminology, economics, geography, history, political science, and psychology, we assemble and analyze the most rigorous quantitative studies and document, for the first time, a striking convergence of results. We find strong causal evidence linking climatic events to human conflict across a range of spatial and temporal scales and across all major regions of the world. The magnitude of climate's influence is substantial: for each one standard deviation (1sd) change in climate toward warmer temperatures or more extreme rainfall, median estimates indicate that the frequency of interpersonal violence rises 4% and the frequency of intergroup conflict rises 14%. Because locations throughout the inhabited world are expected to warm 2sd to 4sd by 2050, amplified rates of human conflict could represent a large and critical impact of anthropogenic climate change.

High-density amorphous ice: A path-integral simulation

NASA Astrophysics Data System (ADS)

Herrero, Carlos P.; Ramírez, Rafael

2012-09-01

Structural and thermodynamic properties of high-density amorphous (HDA) ice have been studied by path-integral molecular dynamics simulations in the isothermal-isobaric ensemble. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. Quantum nuclear motion is found to affect several observable properties of the amorphous solid. At low temperature (T = 50 K) the molar volume of HDA ice is found to increase by 6%, and the intramolecular O-H distance rises by 1.4% due to quantum motion. Peaks in the radial distribution function of HDA ice are broadened with respect to their classical expectancy. The bulk modulus, B, is found to rise linearly with the pressure, with a slope ∂B/∂P = 7.1. Our results are compared with those derived earlier from classical and path-integral simulations of HDA ice. We discuss similarities and discrepancies with those earlier simulations.

Western water and climate change

USGS Publications Warehouse

Dettinger, Michael; Udall, Bradley; Georgakakos, Aris P.

2015-01-01

In this context, four iconic river basins offer glimpses into specific challenges that climate change may bring to the West. The Colorado River is a system in which overuse and growing demands are projected to be even more challenging than climate-change-induced flow reductions. The Rio Grande offers the best example of how climate-change-induced flow declines might sink a major system into permanent drought. The Klamath is currently projected to face the more benign precipitation future, but fisheries and irrigation management may face dire straits due to warming air temperatures, rising irrigation demands, and warming waters in a basin already hobbled by tensions between endangered fisheries and agricultural demands. Finally, California's Bay-Delta system is a remarkably localized and severe weakness at the heart of the region's trillion-dollar economy. It is threatened by the full range of potential climate-change impacts expected across the West, along with major vulnerabilities to increased flooding and rising sea levels.

Impact of flows on ion temperatures inferred from neutron spectra in asymmetrically driven OMEGA DT implosions

NASA Astrophysics Data System (ADS)

Gatu Johnson, M.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.; Aappelbe, B.; Chittenden, J.; Walsh, C.; Knauer, J. P.; Glebov, V. Yu.; Forrest, C.; Marshall, F.; Michel, T.; Stoeckl, C.; Sangster, T. C.; Zylstra, A.

2016-10-01

Ion temperatures (Tion) in Inertial Confinement Fusion (ICF) experiments have traditionally been inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn, expected to arise due to asymmetries imposed by engineering features (such as stalks, fill tubes, tents, or capsule imperfections) or drive non-uniformity, also impacts broadening and may lead to artificially inflated ``Tion'' values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured Tion, as observed in OMEGA cryogenic DT implosions but not in similar experiments at the NIF. In this presentation we report on an OMEGA experiment with intentionally asymmetric drive, designed to test the ability to accurately predict and measure line-of-sight differences in apparent Tion due to low-mode asymmetry-seeded flows. The results provide insight into the complexity of hot-spot dynamics, which is a problem that must be mastered to achieve ICF ignition. This work was supported in part by LLE, the U.S. DoE (NNSA, NLUF) and LLNL.

Study on the effect of temperature rise on grain refining during fabrication of nanocrystalline copper under explosive loading

NASA Astrophysics Data System (ADS)

Wang, Jinxiang; Yang, Rui; Jiang, Li; Wang, Xiaoxu; Zhou, Nan

2013-11-01

Nanocrystalline (NC) copper was fabricated by severe plastic deformation of coarse-grained copper at a high strain rate under explosive loading. The feasibility of grain refinement under different explosive loading and the influence of overall temperature rise on grain refinement under impact compression were studied in this paper. The calculation model for the macroscopic temperature rise was established according to the adiabatic shock compression theory. The calculation model for coarse-grained copper was established by the Voronoi method and the microscopic temperature rise resulted from severe plastic deformation of grains was calculated by ANSYS/ls-dyna finite element software. The results show that it is feasible to fabricate NC copper by explosively dynamic deformation of coarse-grained copper and the average grain size of the NC copper can be controlled between 200˜400 nm. The whole temperature rise would increase with the increasing explosive thickness. Ammonium nitrate fuel oil explosive was adopted and five different thicknesses of the explosive, which are 20 mm, 25 mm, 30 mm, 35 mm, 45 mm, respectively, with the same diameter using 20 mm to the fly plate were adopted. The maximum macro and micro temperature rise is up to 532.4 K, 143.4 K, respectively, which has no great effect on grain refinement due to the whole temperature rise that is lower than grain growth temperature according to the high pressure melting theory.

Are all temperate lakes eutrophying in a warmer world?

NASA Astrophysics Data System (ADS)

Paltsev, A.; Creed, I. F.

2017-12-01

Freshwater lakes are at risk of eutrophication due to climate change and intensification of human activities on the planet. In relatively undisturbed areas of the temperate forest biome, lakes are "sentinels" of the effects of rising temperatures. We hypothesise that rising temperatures are driving a shift from nutrient-poor oligotrophic states to nutrient-rich eutrophic states. To test this hypothesis, we examined a time series of satellite based chlorophyll-a (a proxy of algal biomass) of 12,000+ lakes over 30 years in the Canadian portion of the Laurentian Great Lakes basin. From the time series, non-stationary trends (detected by Mann-Kendall analysis) and stationary cycles (revealed through Morlet wavelet analysis) were removed, and the standard deviation (SD) of the remaining residuals was used as an indicator of lake stability. Four classes of lake stability were identified: (1) stable (SD is consistently low); (2) destabilizing (SD increases over time); (3) unstable (SD is consistently high); and (4) stabilizing lakes (SD decreases over time). Stable lakes were either oligotrophic or eutrophic indicating the presence of two stable states in the region. Destabilizing lakes were shifting from oligotrophic to lakes with a higher trophic status (indicating eutrophication), unstable lakes were mostly mesotrophic, and stabilizing lakes were shifting from eutrophic to the lakes with lower trophic status (indicating oligotrophication). In contrast to common expectations, while many lakes (2142) were shifting from oligotrophic to eutrophic states, more lakes (3199) were showing the opposite trend and shifting from eutrophic to oligotrophic states. This finding reveals a complexity of lake responses to rising temperatures and the need to improve understanding of why some lakes shift while others do not. Future work is focused on exploring the interactive effects of global, regional, and local drivers of lake trophic states.

Effect of elevated temperature on soil hydrothermal regimes and growth of wheat crop.

PubMed

Pramanik, P; Chakrabarti, Bidisha; Bhatia, Arti; Singh, S D; Maity, A; Aggarwal, P; Krishnan, P

2018-03-14

An attempt has been made to study the effect of elevated temperature on soil hydrothermal regimes and winter wheat growth under simulated warming in temperature gradient tunnel (TGT). Results showed that bulk density (BDs) of 0, 0.9, and 2.5 °C were significantly different whereas BDs of 2.8 and 3.5 °C were not significantly different. Water filled pore space (WFPS) was maximum at 3.5 °C temperature rise and varied between 43.80 and 98.55%. Soil surface temperature (ST) at different dates of sowing increased with rise in sensor temperature and highest ST was observed at S5 sensors (3.5 °C temperature rise). Temperature and its difference were high for the top soil, and were stable for the deep soil. Photosynthesis rate (μmol CO 2 m -2  s -1 ) of wheat was lower at higher temperature in different growth stages of wheat. In wheat, stomatal conductance declined from 0.67 to 0.44 mol m -2  s -1 with temperature rise. Stomatal conductance decreased with increase in soil temperature and gravimetric soil moisture content (SWC). In TGT, 0 °C temperature rise showed highest root weight density (RWD) (5.95 mg cm -3 ); whereas, 2.8 and 3.5 °C showed lowest RWD (4.90 mg cm -3 ). Harvest index was maximum (0.37) with 0 °C temperature rise, and it decreased with increase in temperature, which indicated that both grain and shoot biomass decreased with increase in temperature. Intensive studies are needed to quantify the soil hydrothermal regimes inside TGT along with the crop growth parameters.

Infrared thermography based studies on mobile phone induced heating

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Bagavathiappan, S.; Soumya, C.; Jayakumar, T.; Philip, John

2015-07-01

Here, we report the skin temperature rise due to the absorption of radio frequency (RF) energy from three handheld mobile phones using infrared thermography technique. Experiments are performed under two different conditions, viz. when the mobile phones are placed in soft touch with the skin surface and away from the skin surface. Additionally, the temperature rise of mobile phones during charging, operation and simultaneous charging and talking are monitored under different exposure conditions. It is observed that the temperature of the cheek and ear regions monotonically increased with time during the usage of mobile phones and the magnitude of the temperature rise is higher for the mobile phone with higher specific absorption rate. The increase in skin temperature is higher when the mobile phones are in contact with the skin surface due to the combined effect of absorption of RF electromagnetic power and conductive heat transfer. The increase in the skin temperature in non-contact mode is found to be within the safety limit of 1 °C. The measured temperature rise is in good agreement with theoretical predictions. The empirical equation obtained from the temperature rise on the cheek region of the subjects correlates well with the specific absorption rate of the mobile phones. Our study suggests that the use of mobile phones in non-contact mode can significantly lower the skin temperature rise during its use and hence, is safer compared to the contact mode.

Temperature Effects on Development and Phenotype in a Free-Living Population of Western Pond Turtles (Emys marmorata).

PubMed

Christie, Nicole E; Geist, Nicholas R

Changes in temperature regimes are occurring globally due to climate change as well as habitat alterations. Temperatures are expected to continue to rise in the future, along with a greater degree of climatic instability. Such changes could have potentially serious consequences for oviparous ectotherms, especially those with temperature-dependent sex determination. To investigate the effects of temperature on a range of developmental phenomena in a population of western pond turtles (Emys marmorata), we placed temperature sensors on top of each layer of eggs within nests and recorded temperatures hourly through the first 2-3 mo of incubation. These methods allowed us to look at in situ nest temperatures with high resolution. We found that mean incubation temperatures were similar between different nests and at different levels within nests but that incubation temperature fluctuations and maximum incubation temperatures differed greatly in both cases. The hatchling turtles were more likely to be female if they spent 30% or more of their sex-determining period of incubation above 29°C. Hatching success was best predicted by the maximum incubation temperature. We also found that incubation duration tended to be shorter as the mean temperature increased. However, exposure to either extremely high or low temperatures extended incubation times.

The observable signature of late heating of the Universe during cosmic reionization.

PubMed

Fialkov, Anastasia; Barkana, Rennan; Visbal, Eli

2014-02-13

Models and simulations of the epoch of reionization predict that spectra of the 21-centimetre transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and the characteristic size of ionized bubbles. This is based on the assumption that the cosmic gas was heated by stellar remnants-particularly X-ray binaries-to temperatures well above the cosmic microwave background at that time (about 30 kelvin). Here we show instead that the hard spectra (that is, spectra with more high-energy photons than low-energy photons) of X-ray binaries make such heating ineffective, resulting in a delayed and spatially uniform heating that modifies the 21-centimetre signature of reionization. Rather than looking for a simple rise and fall of the large-scale fluctuations (peaking at several millikelvin), we must expect a more complex signal also featuring a distinct minimum (at less than a millikelvin) that marks the rise of the cosmic mean gas temperature above the microwave background. Observing this signal, possibly with radio telescopes in operation today, will demonstrate the presence of a cosmic background of hard X-rays at that early time.

Future soil moisture and temperature extremes imply expanding suitability for rainfed agriculture in temperate drylands

USGS Publications Warehouse

Bradford, John B.; Schlaepfer, Daniel R.; Lauenroth, William K.; Yackulic, Charles B.; Duniway, Michael C.; Hall, Sonia A.; Jia, Gensuo; Jamiyansharav, Khishigbayar; Munson, Seth M.; Wilson, Scott D.; Tietjen, Britta

2017-01-01

The distribution of rainfed agriculture is expected to respond to climate change and human population growth. However, conditions that support rainfed agriculture are driven by interactions among climate, including climate extremes, and soil moisture availability that have not been well defined. In the temperate regions that support much of the world’s agriculture, these interactions are complicated by seasonal temperature fluctuations that can decouple climate and soil moisture. Here, we show that suitability to support rainfed agriculture can be effectively represented by the interactive effects of just two variables: suitability increases where warm conditions occur with wet soil, and suitability decreases with extreme high temperatures. 21st century projections based on ecohydrological modeling of downscaled climate forecasts imply geographic shifts and overall increases in the area suitable for rainfed agriculture in temperate regions, especially at high latitudes, and pronounced, albeit less widespread, declines in suitable areas in low latitude drylands, especially in Europe. These results quantify the integrative direct and indirect impact of rising temperatures on rainfed agriculture.

Texture related unusual phenomena in electrodeposition and vapor deposition

NASA Astrophysics Data System (ADS)

Lee, D. N.; Han, H. N.

2015-04-01

The tensile strength of electrodeposits generally decreases with increasing bath temperature because the grain size increases and the dislocation density decreases with increasing bath temperature. Therefore, discontinuities observed in the tensile strength vs. bath temperature curves in electrodeposition of copper are unusual. The tensile strength of electrodeposits generally increases with increasing cathode current density because the rate of nucleation in electrodeposits increases with increasing current density, which in turn gives rise to a decrease in the grain size and in turn an increase in the strength. Therefore, a decrease in the tensile strength of copper electrodeposits at a high current density is unusual. The grain size of vapor deposits is expected to decrease with decreasing substrate temperature. However, rf sputtered Co-Cr deposits showed that deposits formed on water-cooled polyimide substrates had a larger grain size than deposits formed on polyimide substrates at 200 °C. These unusual phenomena can be explained by the preferred growth model for deposition texture evolution.

Comment [on “Sea level rise shown to drive coastal erosion”

USGS Publications Warehouse

Pilkey, Orrin H.; Young, Robert S.; Bush, David M.

2000-01-01

Leatherman et al. [2000] (Eos, Trans., AGU, February 8, 2000, p.55) affirm that global eustatic sea-level rise is driving coastal erosion. Furthermore, they argue that the long-term average rate of shoreline retreat is 150 times the rate of sea-level rise. This rate, they say, is more than a magnitude greater than would be expected from a simple response to sea-level rise through inundation of the shoreline. We agree that sea-level rise is the primary factor causing shoreline retreat in stable coastal areas.This is intuitive. We also believe, however, that the Leatherman et al. [2000] study has greatly underestimated the rate of coastal recession along most low slope shorelines. Slopes along the North Carolina continental shelf/coastal plain approach 10,000:1. To us, this suggests that we should expect rates of shoreline recession 10,000 times the rate of sea-level rise through simple inundation of the shoreline.

Come rain or shine? Public expectation on local weather change and differential effects on climate change attitude.

PubMed

Lo, Alex Y; Jim, C Y

2015-11-01

Tailored messages are instrumental to climate change communication. Information about the global threat can be 'localised' by demonstrating its linkage with local events. This research ascertains the relationship between climate change attitude and perception of local weather, based on a survey involving 800 Hong Kong citizens. Results indicate that concerns about climate change increase with expectations about the likelihood and impacts of local weather change. Climate change believers attend to all three types of adverse weather events, namely, temperature rises, tropical cyclones and prolonged rains. Climate scepticism, however, is not associated with expectation about prolonged rains. Differential spatial orientations are a possible reason. Global climate change is an unprecedented and distant threat, whereas local rain is a more familiar and localised weather event. Global climate change should be articulated in terms that respect local concerns. Localised framing may be particularly effective for engaging individuals holding positive views about climate change science. © The Author(s) 2014.

Climate Change in the Western United States: Projections and Observations (Invited)

NASA Astrophysics Data System (ADS)

Redmond, K. T.

2009-12-01

The interplay between projections and observations of climate, and the role of observations as they unfold, form the primary emphasis for this talk. The consensus among climate projections is that the Western United States will warm, and that annual precipitation will increase near the Canada/US border and decrease near the Mexico/US border. Inter-model agreement is greater for temperature than precipitation, though precipitation projections show some tendency toward slow convergence. Seasonal temperature changes are expected to be similar from month to month, slightly greater in summer and slightly smaller in winter. Coastal temperature increases are expected to be smaller than inland. High elevation increases may be slightly greater than those at low elevation. The precipitation season is in general expected to be more concentrated in winter, with less (or less increase, depending on latitude) precipitation in spring, summer, and autumn than without climate change. Climate should have started to depart from the baseline (no-change) case about 30-35 years ago. Observations show that temperatures West-wide did begin to rise during the 1970s. Precipitation changes have been more ambiguous. Annual temperature increases in the U.S. have been much more prominent in the West (and to some extent the north) than in the East, especially during the last decade. Summer in particular has shown a marked temperature increase since around 2000. Minimum temperatures have shown more increase (in many cases considerably more) than maximum temperatures. Annual freezing levels, from essentially independent data sets, have risen during this time. Acceptance of climate change in the public mind is increased when evidence visibly aligns with projections. This appears to have been particularly important in the western states. However, other sources of climate variability, of human or natural origin, on seasonal to decadal scales, can obscure or partially and temporarily mask expected effects of greenhouse gas forcing. Observational factors can likewise affect the reported climate history. Changes in climate elements have been detected, but parallel efforts at attribution are necessary to properly interpret the measurements, and provide the consistency desired by scientists and the remainder of the public. All of the above factors converge in the region's most prominent climate narrative, the ongoing Colorado River drought and its uncertain outcome.

Atlantic hurricane surge response to geoengineering

PubMed Central

Moore, John C.; Grinsted, Aslak; Guo, Xiaoran; Yu, Xiaoyong; Jevrejeva, Svetlana; Rinke, Annette; Cui, Xuefeng; Kravitz, Ben; Lenton, Andrew; Watanabe, Shingo; Ji, Duoying

2015-01-01

Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges. PMID:26504210

Calculation of change in brain temperatures due to exposure to a mobile phone

NASA Astrophysics Data System (ADS)

Van Leeuwen, G. M. J.; Lagendijk, J. J. W.; Van Leersum, B. J. A. M.; Zwamborn, A. P. M.; Hornsleth, S. N.; Kotte, A. N. T. J.

1999-10-01

In this study we evaluated for a realistic head model the 3D temperature rise induced by a mobile phone. This was done numerically with the consecutive use of an FDTD model to predict the absorbed electromagnetic power distribution, and a thermal model describing bioheat transfer both by conduction and by blood flow. We calculated a maximum rise in brain temperature of 0.11 °C for an antenna with an average emitted power of 0.25 W, the maximum value in common mobile phones, and indefinite exposure. Maximum temperature rise is at the skin. The power distributions were characterized by a maximum averaged SAR over an arbitrarily shaped 10 g volume of approximately 1.6 W kg-1. Although these power distributions are not in compliance with all proposed safety standards, temperature rises are far too small to have lasting effects. We verified our simulations by measuring the skin temperature rise experimentally. Our simulation method can be instrumental in further development of safety standards.

The Effect of Spatial Aggregation on the Skill of Seasonal Precipitation Forecasts.

NASA Astrophysics Data System (ADS)

Gong, Xiaofeng; Barnston, Anthony G.; Ward, M. Neil

2003-09-01

Skillful forecasts of 3-month total precipitation would be useful for decision making in hydrology, agriculture, public health, and other sectors of society. However, with some exceptions, the skill of seasonal precipitation outlooks is modest, leaving uncertainty in how to best make use of them. Seasonal precipitation forecast skill is generally lower than the skill of forecasts for temperature or atmospheric circulation patterns for the same location and time. This is attributable to the smaller-scale, more complex physics of precipitation, resulting in its `noisier' and hence less predictable character. By contrast, associated temperature and circulation patterns are larger scale, in keeping with the anomalous boundary conditions (e.g., sea surface temperature) that often give rise to them.Using two atmospheric general circulation models forced by observed sea surface temperature anomalies, the skill of simulations of total seasonal precipitation is examined as a function of the size of the spatial domain over which the precipitation total is averaged. Results show that spatial aggregation increases skill and, by the skill measures used here, does so to a greater extent for precipitation than for temperature. Corroborative results are presented in an observational framework at smaller spatial scales for gauge rainfalls in northeast Brazil.The findings imply that when seasonal forecasts for precipitation are issued, the accompanying guidance on their expected skills should explicitly specify to which spatial aggregation level the skills apply. Information about skills expected at other levels of aggregation should be supplied for users who may work at such levels.

Beliefs and expectations of Canadian parents who bring febrile children for medical care.

PubMed

Enarson, Mark C; Ali, Samina; Vandermeer, Ben; Wright, Robert B; Klassen, Terry P; Spiers, Judith A

2012-10-01

The purpose of this survey was to study the beliefs, expectations, and satisfaction of Canadian parents regarding fever and the treatment of their febrile children. A survey was developed exploring caregiver beliefs and treatment strategies, as well as expectations and satisfaction with medical care. Some items were modeled after previous studies to allow comparison. Caregivers with febrile children were recruited from 2005 to 2007 at 3 urgent care centers and emergency departments in Edmonton, Canada: a pediatric emergency department (n = 376), an urban urgent care center (n = 227), and a suburban urgent care clinic (n = 173). High and rapidly rising temperature, as well as physical symptoms associated with fever, caused concern in most parents surveyed. Seventy-four percent of parents felt that the elevated temperature from fever was dangerous and 90.3% always try to treat it. Forty degrees Celsius was the most commonly sited threshold for danger. Identifying the cause (80.6%) and seriousness (87.4%) of fever were the most com-mon stressors identified. Caregivers expected to receive information about the child's illness and appropriate treatment. The parents most often wanted information about febrile seizures and the potential dangers of febrile illness. Only 16.7% of caregivers expected anti-biotics. Nearly 92% of subjects were usually satisfied with medical care. Fever phobia continues to be a significant issue for Canadian parents. As a result, they treat fever aggressively and often seek medical attention. Good communication is important for medical staff caring for febrile children and typically leads to satisfied parents.

An extensive study of Bose-Einstein condensation in liquid helium using Tsallis statistics

NASA Astrophysics Data System (ADS)

Guha, Atanu; Das, Prasanta Kumar

2018-05-01

Realistic scenario can be represented by general canonical ensemble way better than the ideal one, with proper parameter sets involved. We study the Bose-Einstein condensation phenomena of liquid helium within the framework of Tsallis statistics. With a comparatively high value of the deformation parameter q(∼ 1 . 4) , the theoretically calculated value of the critical temperature (Tc) of the phase transition of liquid helium is found to agree with the experimentally determined value (Tc = 2 . 17 K), although they differs from each other for q = 1 (undeformed scenario). This throws a light on the understanding of the phenomenon and connects temperature fluctuation(non-equilibrium conditions) with the interactions between atoms qualitatively. More interactions between atoms give rise to more non-equilibrium conditions which is as expected.

Climate change effects on human health: projections of temperature-related mortality for the UK during the 2020s, 2050s and 2080s.

PubMed

Hajat, Shakoor; Vardoulakis, Sotiris; Heaviside, Clare; Eggen, Bernd

2014-07-01

The most direct way in which climate change is expected to affect public health relates to changes in mortality rates associated with exposure to ambient temperature. Many countries worldwide experience annual heat-related and cold-related deaths associated with current weather patterns. Future changes in climate may alter such risks. Estimates of the likely future health impacts of such changes are needed to inform public health policy on climate change in the UK and elsewhere. Time-series regression analysis was used to characterise current temperature-mortality relationships by region and age group. These were then applied to the local climate and population projections to estimate temperature-related deaths for the UK by the 2020s, 2050s and 2080s. Greater variability in future temperatures as well as changes in mean levels was modelled. A significantly raised risk of heat-related and cold-related mortality was observed in all regions. The elderly were most at risk. In the absence of any adaptation of the population, heat-related deaths would be expected to rise by around 257% by the 2050s from a current annual baseline of around 2000 deaths, and cold-related mortality would decline by 2% from a baseline of around 41 000 deaths. The cold burden remained higher than the heat burden in all periods. The increased number of future temperature-related deaths was partly driven by projected population growth and ageing. Health protection from hot weather will become increasingly necessary, and measures to reduce cold impacts will also remain important in the UK. The demographic changes expected this century mean that the health protection of the elderly will be vital. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Estimating the impact of +2 degrees of global warming on European Tourism

NASA Astrophysics Data System (ADS)

Tsanis, Ioannis; Koutroulis, Aristeidis; Grillakis, Manolis; Konstantopoulos, Konstantinos; Jacob, Daniela

2014-05-01

The impact of a potential global temperature rise by 2oC on tourism is examined, within the framework of IMPACT2C FP7 project. The period of the specific increase was defined according to the global mean temperature projections from two GCM, BCM and HadCM3Q3. Simulations from two RCMs, driven by the aforementioned GCMs, in the frame of ENSEMBLES FP6 under A1B emission scenario were used to estimate the Tourism Climatic Index (TCI) which is a measure of climate favorability for outdoor leisure and recreational activities. Climate favorability related to summer tourism is expected to increase in most European countries moving from south to north. In the opposite, countries that traditionally attract "sun and sand" tourists like Italy, Spain, Greece, France, Portugal, Cyprus are projected to become uncomfortably hot for the months of the peak summer season. Both of the examined models provide consistent information about the direction of change, however SMHI shows a greater change in future TCI. The TCI between 1960 and 2000 was associated to bednights data, to reveal the correlation of the empirical index with a real tourism indicator. The resulted correlation function was then applied to the 2oC period, estimating the effect of the specific temperature rise to future tourism activity expressed in terms of projected bednights.

Observations of temperature rise during electron cyclotron heating application in Proto-MPEX

NASA Astrophysics Data System (ADS)

Biewer, T. M.; Bigelow, T.; Caneses, J. F.; Diem, S. J.; Rapp, J.; Reinke, M.; Kafle, N.; Ray, H. B.; Showers, M.

2017-10-01

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at ORNL utilizes a variety of power systems to generate and deliver a high heat flux plasma (1 MW/m2 for these discharges) onto the surface of material targets. In the experiments described here, up to 120 kW of 13.56 MHz ``helicon'' waves are combined with 20 kW of 28 GHz microwaves to produce Deuterium plasma discharges. The 28 GHz waves are launched in a region of the device where the magnetic field is axially varying near 0.8 T, resulting in the presence of a 2nd harmonic electron cyclotron heating (ECH) resonance layer that transects the plasma column. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is radially peaked. In the core of the plasma column the electron density is higher than the cut-off density (0.9x1019 m-3) for ECH waves to propagate and O-X-B mode conversion into electron Bernstien waves (EBW) is expected. TS measurements indicate electron temperature increases during 28 GHz wave application, rising (from 5 eV to 20 eV) as the neutral Deuterium pressure is reduced below 1 mTorr. This work was supported by the US. D.O.E. contract DE-AC05-00OR22725.

Exact-solution for cone-plate viscometry

NASA Astrophysics Data System (ADS)

Giacomin, A. J.; Gilbert, P. H.

2017-11-01

The viscosity of a Newtonian fluid is often measured by confining the fluid to the gap between a rotating cone that is perpendicular to a fixed disk. We call this experiment cone-plate viscometry. When the cone angle approaches π/2 , the viscometer gap is called narrow. The shear stress in the fluid, throughout a narrow gap, hardly departs from the shear stress exerted on the plate, and we thus call cone-plate flow nearly homogeneous. In this paper, we derive an exact solution for this slight heterogeneity, and from this, we derive the correction factors for the shear rate on the cone and plate, for the torque, and thus, for the measured Newtonian viscosity. These factors thus allow the cone-plate viscometer to be used more accurately, and with cone-angles well below π/2 . We find cone-plate flow field heterogeneity to be far slighter than previously thought. We next use our exact solution for the velocity to arrive at the exact solution for the temperature rise, due to viscous dissipation, in cone-plate flow subject to isothermal boundaries. Since Newtonian viscosity is a strong function of temperature, we expect our new exact solution for the temperature rise be useful to those measuring Newtonian viscosity, and especially so, to those using wide gaps. We include two worked examples to teach practitioners how to use our main results.

Temperature rise and flow of Zr-based bulk metallic glasses under high shearing stress

NASA Astrophysics Data System (ADS)

Zhang, Weiguo; Ma, Mingzhen; Song, Aijun; Liang, Shunxing; Hao, Qiuhong; Tan, Chunlin; Jing, Qin; Liu, Riping

2011-11-01

Deformation of the bulk metallic glasses (BMGs) and the creation and propagation of the shear bands are closely interconnected. Shearing force was loaded on Zr41.2Ti13.8Cu12.5Ni10.0Be22.5(Vit.1) BMGs by cutting during the turning of the BMG rod. The temperature rise of alloy on the shear bands was calculated and the result showed that it could reach the temperature of the super-cooled liquid zone or exceed the melting point. The temperature rise caused viscous fluid flow and brought about the deformation of BMGs. This suggested that the deformation of BMGs was derived, at least to some extent, from the adiabatic shear temperature rise.

KSC-02pd1858

NASA Image and Video Library

2002-12-05

KENNEDY SPACE CENTER, FLA. - Stephen Ezell, meteorological systems operator at Weather Station A, Cape Canaveral Air Force Station, gets ready to release a weather balloon. Such balloons are released twice a day. The package in Ezell's hand is a radio sonde that collects temperature and humidity data as the balloon rises. The data is released to agencies nationwide, including the 45th Space Wing, which uses the data for its daily weather reports. The weather station provides additional data to NASA for launches -- releasing 12 balloons in eight hours prior to liftoff - and landings - releasing 5 balloons in six and a half hours before expected touchdown.

KSC-02pd1859

NASA Image and Video Library

2002-12-05

KENNEDY SPACE CENTER, FLA. -- Stephen Ezell, meteorological systems operator at Weather Station A, Cape Canaveral Air Force Station, releases a weather balloon. Such balloons are released twice a day. The package at the bottom is a radio sonde that collects temperature and humidity data as the balloon rises. The data is released to agencies nationwide, including the 45th Space Wing, which uses the data for its daily weather reports. The weather station provides additional data to NASA for launches -- releasing 12 balloons in eight hours prior to liftoff - and landings - releasing 5 balloons in six and a half hours before expected touchdown.

KSC-02pd1857

NASA Image and Video Library

2002-12-05

KENNEDY SPACE CENTER, FLA. - Stephen Ezell, meteorological systems operator at Weather Station A, Cape Canaveral Air Force Station, gets ready to release a weather balloon. Such balloons are released twice a day. The package in Ezell's hand is a radio sonde that collects temperature and humidity data as the balloon rises. The data is released to agencies nationwide, including the 45th Space Wing, which uses the data for its daily weather reports. The weather station provides additional data to NASA for launches -- releasing 12 balloons in eight hours prior to liftoff - and landings - releasing 5 balloons in six and a half hours before expected touchdown.

Increasing atmospheric humidity and CO 2 concentration alleviate forest mortality risk

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

Liu, Yanlan; Parolari, Anthony J.; Kumar, Mukesh

Climate-induced forest mortality is being increasingly observed throughout the globe. Alarmingly, it is expected to exacerbate under climate change due to shifting precipitation patterns and rising air temperature. However, the impact of concomitant changes in atmospheric humidity and CO 2 concentration through their influence on stomatal kinetics remains a subject of debate and inquiry. By using a dynamic soil–plant–atmosphere model, mortality risks associated with hydraulic failure and stomatal closure for 13 temperate and tropical forest biomes across the globe are analyzed. The mortality risk is evaluated in response to both individual and combined changes in precipitation amounts and their seasonalmore » distribution, mean air temperature, specific humidity, and atmospheric CO 2 concentration. Model results show that the risk is predicted to significantly increase due to changes in precipitation and air temperature regime for the period 2050–2069. However, this increase may largely get alleviated by concurrent increases in atmospheric specific humidity and CO 2 concentration. The increase in mortality risk is expected to be higher for needleleaf forests than for broadleaf forests, as a result of disparity in hydraulic traits. These findings will further facilitate decisions about intervention and management of different forest types under changing climate.« less

Increasing atmospheric humidity and CO 2 concentration alleviate forest mortality risk

DOE PAGES

Liu, Yanlan; Parolari, Anthony J.; Kumar, Mukesh; ...

2017-08-28

Climate-induced forest mortality is being increasingly observed throughout the globe. Alarmingly, it is expected to exacerbate under climate change due to shifting precipitation patterns and rising air temperature. However, the impact of concomitant changes in atmospheric humidity and CO 2 concentration through their influence on stomatal kinetics remains a subject of debate and inquiry. By using a dynamic soil–plant–atmosphere model, mortality risks associated with hydraulic failure and stomatal closure for 13 temperate and tropical forest biomes across the globe are analyzed. The mortality risk is evaluated in response to both individual and combined changes in precipitation amounts and their seasonalmore » distribution, mean air temperature, specific humidity, and atmospheric CO 2 concentration. Model results show that the risk is predicted to significantly increase due to changes in precipitation and air temperature regime for the period 2050–2069. However, this increase may largely get alleviated by concurrent increases in atmospheric specific humidity and CO 2 concentration. The increase in mortality risk is expected to be higher for needleleaf forests than for broadleaf forests, as a result of disparity in hydraulic traits. These findings will further facilitate decisions about intervention and management of different forest types under changing climate.« less

Simulated Altitude Performance of Combustor of Westinghouse 19XB-1 Jet-Propulsion Engine

NASA Technical Reports Server (NTRS)

Childs, J. Howard; McCafferty, Richard J.

1948-01-01

A 19XB-1 combustor was operated under conditions simulating zero-ram operation of the 19XB-1 turbojet engine at various altitudes and engine speeds. The combustion efficiencies and the altitude operational limits were determined; data were also obtained on the character of the combustion, the pressure drop through the combustor, and the combustor-outlet temperature and velocity profiles. At altitudes about 10,000 feet below the operational limits, the flames were yellow and steady and the temperature rise through the combustor increased with fuel-air ratio throughout the range of fuel-air ratios investigated. At altitudes near the operational limits, the flames were blue and flickering and the combustor was sluggish in its response to changes in fuel flow. At these high altitudes, the temperature rise through the combustor increased very slowly as the fuel flow was increased and attained a maximum at a fuel-air ratio much leaner than the over-all stoichiometric; further increases in fuel flow resulted in decreased values of combustor temperature rise and increased resonance until a rich-limit blow-out occurred. The approximate operational ceiling of the engine as determined by the combustor, using AN-F-28, Amendment-3, fuel, was 30,400 feet at a simulated engine speed of 7500 rpm and increased as the engine speed was increased. At an engine speed of 16,000 rpm, the operational ceiling was approximately 48,000 feet. Throughout the range of simulated altitudes and engine speeds investigated, the combustion efficiency increased with increasing engine speed and with decreasing altitude. The combustion efficiency varied from over 99 percent at operating conditions simulating high engine speed and low altitude operation to less than 50 percent at conditions simulating operation at altitudes near the operational limits. The isothermal total pressure drop through the combustor was 1.82 times as great as the inlet dynamic pressure. As expected from theoretical considerations, a straight-line correlation was obtained when the ratio of the combustor total pressure drop to the combustor-inlet dynamic pressure was plotted as a function of the ratio of the combustor-inlet air density to the combustor-outlet gas density. The combustor-outlet temperature profiles were, in general, more uniform for runs in which the temperature rise was low and the combustion efficiency was high. Inspection of the combustor basket after 36 hours of operation showed very little deterioration and no appreciable carbon deposits.

46 CFR 111.20-5 - Temperature rise.

Code of Federal Regulations, 2012 CFR

2012-10-01

... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The... than 40 degrees C, the transformer must be derated so that the total temperature stated in this section...

46 CFR 111.20-5 - Temperature rise.

Code of Federal Regulations, 2014 CFR

2014-10-01

... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The... than 40 degrees C, the transformer must be derated so that the total temperature stated in this section...

46 CFR 111.20-5 - Temperature rise.

Code of Federal Regulations, 2013 CFR

2013-10-01

... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The... than 40 degrees C, the transformer must be derated so that the total temperature stated in this section...

46 CFR 111.20-5 - Temperature rise.

Code of Federal Regulations, 2010 CFR

2010-10-01

... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The... than 40 degrees C, the transformer must be derated so that the total temperature stated in this section...

46 CFR 111.20-5 - Temperature rise.

Code of Federal Regulations, 2011 CFR

2011-10-01

... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The... than 40 degrees C, the transformer must be derated so that the total temperature stated in this section...

Temperature Rise in Kirschner Wires Inserted Using Two Drilling Methods: Forward and Oscillation.

PubMed

Anderson, Scott Richard; Inceoglu, Serkan; Wongworawat, Montri D

2017-05-01

Kirschner wires (K-wires) are commonly used in orthopedic surgery. However, the loosening of the pins can lead to delayed or improper healing or infection. Wire loosening can occur by thermal necrosis that occurs due to heat produced during wire insertion. Although the parameters that affect temperature rise in cortical bone during wire insertion and drilling have been studied, the effect of drilling mode (oscillation versus forward) is unknown. The purpose of this study was to compare the temperature changes occurring in cortical bone during wire insertions by oscillating and forward drills. Our hypothesis is that oscillation drilling would produce less heat compared with forward drilling in K-wire insertion with 2 commonly used wire diameters. We drilled K-wires in a pig metacarpal model and measured the temperature rise between forward and oscillation drilling modes using diamond-tipped 0.062- and 0.045-inch-diameter K-wires. There were 20 holes drilled for each group (n = 20). The average temperature rise using the 0.062-inch K-wire under forward and oscillation insertion was 14.0 ± 5.5°C and 8.8 ± 2.6°C, respectively. For the 0.045-inch K-wire, under forward and oscillation insertion, the average temperature rise was 11.4 ± 2.6°C and 7.1 ± 1.9°C, respectively. The effects of the drilling mode and wire diameter on temperature rise were significant ( P < .05). In conclusion, the oscillation of K-wires during insertion causes a lower temperature rise when compared with forward drilling.

Impacts of temperature and its variability on mortality in New England

NASA Astrophysics Data System (ADS)

Shi, Liuhua; Kloog, Itai; Zanobetti, Antonella; Liu, Pengfei; Schwartz, Joel D.

2015-11-01

Rapid build-up of greenhouse gases is expected to increase Earth’s mean surface temperature, with unclear effects on temperature variability. This makes understanding the direct effects of a changing climate on human health more urgent. However, the effects of prolonged exposures to variable temperatures, which are important for understanding the public health burden, are unclear. Here we demonstrate that long-term survival was significantly associated with both seasonal mean values and standard deviations of temperature among the Medicare population (aged 65+) in New England, and break that down into long-term contrasts between ZIP codes and annual anomalies. A rise in summer mean temperature of 1 °C was associated with a 1.0% higher death rate, whereas an increase in winter mean temperature corresponded to a 0.6% decrease in mortality. Increases in standard deviations of temperature for both summer and winter were harmful. The increased mortality in warmer summers was entirely due to anomalies, whereas it was long-term average differences in the standard deviation of summer temperatures across ZIP codes that drove the increased risk. For future climate scenarios, seasonal mean temperatures may in part account for the public health burden, but the excess public health risk of climate change may also stem from changes of within-season temperature variability.

Effect of light-enhanced bleaching on in vitro surface and intrapulpal temperature rise.

PubMed

Baik, J W; Rueggeberg, F A; Liewehr, F R

2001-01-01

This study investigated the effect of the presence, absence, and aging of a heat-enhancing compound (colorant) added to bleaching gel on the temperature rise of the gel itself, as well as the temperature rise within the pulp chamber, when a tooth was exposed to a variety of light-curing units in vitro. An extracted human upper central incisor was fitted with thermocouples placed in the pulp chamber as well as on the facial tooth surface. A temperature-controlled simulated intrapulpal fluid flow was provided to the tooth, and bleaching agent (Opalesence XTRA, Ultradent) containing heat-enhancing colorant, aged colorant, or no colorant was applied to the facial surface. The tooth and light-curing unit were placed in a thermostatically controlled oven at 37 degrees C, and real-time gel and intrapulpal temperature values were recorded digitally. Light-curing units used were a plasma arc light (PAC) (PowerPac, ADT), a conventional quartz tungsten halogen source (QTH) (Optilux 501, Demetron/Kerr), the QTH light used in high-power (bleaching) mode, and an argon ion laser (AccuCure 3000, LaserMed). An exposure scenario simulating light-enhanced bleaching of 10 upper teeth was developed. Temperature rise over the pre-exposure, baseline value associated with the last light exposure in the bleaching sequence was calculated for each curing and bleaching combination. Five replications for each test condition were made. Temperature rise values were compared using analysis of variance (ANOVA) at a preset alpha of 0.05. When fresh colorant-containing bleach was used, the PAC light increased bleach temperature 39.3 degrees C above baseline. With no added colorant, temperature rise was 37.1 degrees C. The QTH light in bleach mode resulted in gel temperature 24.8 degrees C above baseline, whereas the temperature increase was only 11.5 degrees C when no colorant was used. Conventional QTH light use increased fresh bleach temperature by 17.7 degrees C, whereas an increase of only 11.1 degrees C was measured without colorant. The argon ion laser produced equivalent temperature rise regardless of the presence or freshness of the colorant, approximately 9.4 degrees C. Intrapulpal temperatures were all significantly lower than those recorded in the bleaching gel and ranged from 5 degrees to 8 degrees C. As a rule, the presence of fresh heat-enhancing colorant in the bleaching gel resulted in a significant intrapulpal temperature increase (approximately 1 degrees C) over that reached using other lights. The PAC and the QTH light used in bleach mode induced greater intrapulpal temperature rise than the laser. Freshness of bleaching agent incorporating light-activated, heat-enhancing colorant influences temperature rise of bleaching gel and also may increase intrapulpal temperature values. Use of intense lights does elevate bleach temperature and also results in increased intrapulpal temperature that may further impact on patient sensitivity and pulpal health resulting from this treatment.

Temperature-dependent thermal properties of ex vivo liver undergoing thermal ablation.

PubMed

Guntur, Sitaramanjaneya Reddy; Lee, Kang Il; Paeng, Dong-Guk; Coleman, Andrew John; Choi, Min Joo

2013-10-01

Thermotherapy uses a heat source that raises temperatures in the target tissue, and the temperature rise depends on the thermal properties of the tissue. Little is known about the temperature-dependent thermal properties of tissue, which prevents us from accurately predicting the temperature distribution of the target tissue undergoing thermotherapy. The present study reports the key thermal parameters (specific heat capacity, thermal conductivity and heat diffusivity) measured in ex vivo porcine liver while being heated from 20 ° C to 90 ° C and then naturally cooled down to 20 ° C. The study indicates that as the tissue was heated, all the thermal parameters resulted in plots with asymmetric quasi-parabolic curves with temperature, being convex downward with their minima at the turning temperature of 35-40 ° C. The largest change was observed for thermal conductivity, which decreased by 9.6% from its initial value (at 20 ° C) at the turning temperature (35 ° C) and rose by 45% at 90 ° C from its minimum (at 35 ° C). The minima were 3.567 mJ/(m(3) ∙ K) for specific heat capacity, 0.520 W/(m.K) for thermal conductivity and 0.141 mm(2)/s for thermal diffusivity. The minimum at the turning temperature was unique, and it is suggested that it be taken as a characteristic value of the thermal parameter of the tissue. On the other hand, the thermal parameters were insensitive to temperature and remained almost unchanged when the tissue cooled down, indicating that their variations with temperature were irreversible. The rate of the irreversible rise at 35 ° C was 18% in specific heat capacity, 40% in thermal conductivity and 38.3% in thermal diffusivity. The study indicates that the key thermal parameters of ex vivo porcine liver vary largely with temperature when heated, as described by asymmetric quasi-parabolic curves of the thermal parameters with temperature, and therefore, substantial influence on the temperature distribution of the tissue undergoing thermotherapy is expected. 2013. Published by Elsevier Inc

An in vitro investigation of the temperature rises produced in dentine by Nd:YAG laser light with and without water cooling.

PubMed

Gow, A M; McDonald, A V; Pearson, G J; Setchell, D J

1999-01-01

Infrared lasers are reported to have thermal side effects which may damage pulp tissue. This study investigated the thermal effects of the pulsed Nd:YAG laser. Prepared, extracted teeth were measured prior to irradiation. Temperature was recorded using a thermocouple/data logging system. Laser irradiation was carried out with or without water spray for an exposure time of ten seconds. Results indicated that dry irradiation produced unacceptable temperature rises with dentine thicknesses used. Wet irradiation produced a significantly lower temperature rise. It was concluded that the Nd:YAG laser produced thermal effects which could potentially cause pulpal trauma. A water coolant was effective in reducing these thermal effects, but the temperature rise achieved whilst using water coolant may still cause pulpal damage.

Expectancy bias in anxious samples

PubMed Central

Cabeleira, Cindy M.; Steinman, Shari A.; Burgess, Melissa M.; Bucks, Romola S.; MacLeod, Colin; Melo, Wilson; Teachman, Bethany A.

2014-01-01

While it is well documented that anxious individuals have negative expectations about the future, it is unclear what cognitive processes give rise to this expectancy bias. Two studies are reported that use the Expectancy Task, which is designed to assess expectancy bias and illuminate its basis. This task presents individuals with valenced scenarios (Positive Valence, Negative Valence, or Conflicting Valence), and then evaluates their tendency to expect subsequent future positive relative to negative events. The Expectancy Task was used with low and high trait anxious (Study 1: N = 32) and anxiety sensitive (Study 2: N = 138) individuals. Results suggest that in the context of physical concerns, both high anxious samples display a less positive expectancy bias. In the context of social concerns, high trait anxious individuals display a negative expectancy bias only when negatively valenced information was previously presented. Overall, this suggests that anxious individuals display a less positive expectancy bias, and that the processes that give rise to this bias may vary by type of situation (e.g., social or physical) or anxiety difficulty. PMID:24798678

Prediction and Measurement of Temperature Rise Induced by High Intensity Focused Ultrasound in a Tissue-Mimicking Phantom

NASA Astrophysics Data System (ADS)

Lee, Kang Il

2018-06-01

The present study aims to predict the temperature rise induced by high intensity focused ultrasound (HIFU) in soft tissues to assess tissue damage during HIFU thermal therapies. With the help of a MATLAB-based software package developed for HIFU simulation, the HIFU field was simulated by solving the axisymmetric Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation from the frequency-domain perspective, and the HIFU-induced temperature rise in a tissue-mimicking phantom was simulated by solving Pennes' bioheat transfer (BHT) equation. In order to verify the simulation results, we performed in-vitro heating experiments on a tissue-mimicking phantom by using a 1.1-MHz, single-element, spherically focused HIFU transducer. The temperature rise near the focal spot obtained from the HIFU simulator was in good agreement with that from the in-vitro experiments. This confirms that the HIFU simulator based on the KZK and the BHT equations captures the HIFU-induced temperature rise in soft tissues well enough to make it suitable for HIFU treatment planning.

Effects of a drill diameter on the temperature rise in a bone during implant site preparation under clinical conditions.

PubMed

Bogovič, Valerija; Svete, Andrej; Bajsić, Ivan

2016-10-01

Heat, generated during the drilling of a dental implant site preparation, leads to a temperature rise and consequently to a thermal injury of the bone tissue surrounding the implant site, which can cause the subsequent implant failure. In this article, we present new findings related to the temperature rise during implant site drilling under real conditions on a bovine rib bone specimen. The experiments were designed with the help of a full-factorial design in randomized complete blocks, where the main effects of the drill diameter in combination with the drilling force and the drilling speed, and their interactions, on the temperature rise were determined. The temperature rise in the bone under real conditions was measured as the implant site was being prepared by a dentist using intermittent, graduated drilling and external irrigation. Results show that the drill diameter has statistically significant effect, independent of the drilling procedure used. Among the examined drilling parameters, the drill diameter has the greatest effect, where an increase in the drill diameter first causes a decrease in the temperature rise and further increase in the drill diameter causes its increase. During the continuous and one-step drilling, the temperatures of the bones were up to 40.5 °C and during the drilling under actual conditions up to 30.11 °C. © IMechE 2016.

Effects of Ocean Acidification and Temperature Increases on the Photosynthesis of Tropical Reef Calcified Macroalgae.

PubMed

Scherner, Fernando; Pereira, Cristiano Macedo; Duarte, Gustavo; Horta, Paulo Antunes; E Castro, Clovis Barreira; Barufi, José Bonomi; Pereira, Sonia Maria Barreto

2016-01-01

Climate change is a global phenomenon that is considered an important threat to marine ecosystems. Ocean acidification and increased seawater temperatures are among the consequences of this phenomenon. The comprehension of the effects of these alterations on marine organisms, in particular on calcified macroalgae, is still modest despite its great importance. There are evidences that macroalgae inhabiting highly variable environments are relatively resilient to such changes. Thus, the aim of this study was to evaluate experimentally the effects of CO2-driven ocean acidification and temperature rises on the photosynthesis of calcified macroalgae inhabiting the intertidal region, a highly variable environment. The experiments were performed in a reef mesocosm in a tropical region on the Brazilian coast, using three species of frondose calcifying macroalgae (Halimeda cuneata, Padina gymnospora, and Tricleocarpa cylindrica) and crustose coralline algae. The acidification experiment consisted of three treatments with pH levels below those occurring in the region (-0.3, -0.6, -0.9). For the temperature experiment, three temperature levels above those occurring naturally in the region (+1, +2, +4°C) were determined. The results of the acidification experiment indicate an increase on the optimum quantum yield by T. cylindrica and a decline of this parameter by coralline algae, although both only occurred at the extreme acidification treatment (-0.9). The energy dissipation mechanisms of these algae were also altered at this extreme condition. Significant effects of the temperature experiment were limited to an enhancement of the photosynthetic performance by H. cuneata although only at a modest temperature increase (+1°C). In general, the results indicate a possible photosynthetic adaptation and/or acclimation of the studied macroalgae to the expected future ocean acidification and temperature rises, as separate factors. Such relative resilience may be a result of the highly variable environment they inhabit.

Studies on thermo-elastic heating of horns used in ultrasonic plastic welding.

PubMed

Roopa Rani, M; Prakasan, K; Rudramoorthy, R

2015-01-01

Ultrasonic welding horn is half wavelength section or tool used to focus the ultrasonic vibrations to the components being welded. The horn is designed in such a way that it maximizes the amplitude of the sound wave passing through it. The ends of the horn represent the displacement anti-nodes and the center the 'node' of the wave. As the horns perform 20,000 cycles of expansion and contraction per second, they are highly stressed at the nodes and are heated owing to thermo-elastic effects. Considerable temperature rise may be observed in the horn, at the nodal region when working at high amplitudes indicating high stress levels leading to failure of horns due to cyclic loading. The limits for amplitude must therefore be evaluated for the safe working of the horn. Horns made of different materials have different thermo-elastic behaviors and hence different temperatures at the nodes and antinodes. This temperature field can be used as a control mechanism for setting the amplitude/weld parameters. Safe stress levels can be predicted using modal and harmonic analyses followed by a stress analysis to study the effect of cyclic loads. These are achieved using 'Ansys'. The maximum amplitude level obtained from the stress analysis is used as input for 'Comsol' to predict the temperature field. The actual temperature developed in the horn during operation is measured using infrared camera and compared with the simulated temperature. From experiments, it is observed that horn made of titanium had the lowest temperature rise at the critical region and can be expected to operate at amplitudes up to 77 μm without suffering failure due to cyclic loading. The method of predicting thermo-elastic stresses and temperature may be adopted by the industry for operating the horn within the safe stress limits thereby extending the life of the horn. Copyright © 2014 Elsevier B.V. All rights reserved.

Extreme heat in India and anthropogenic climate change

NASA Astrophysics Data System (ADS)

van Oldenborgh, Geert Jan; Philip, Sjoukje; Kew, Sarah; van Weele, Michiel; Uhe, Peter; Otto, Friederike; Singh, Roop; Pai, Indrani; Cullen, Heidi; AchutaRao, Krishna

2018-01-01

On 19 May 2016 the afternoon temperature reached 51.0 °C in Phalodi in the northwest of India - a new record for the highest observed maximum temperature in India. The previous year, a widely reported very lethal heat wave occurred in the southeast, in Andhra Pradesh and Telangana, killing thousands of people. In both cases it was widely assumed that the probability and severity of heat waves in India are increasing due to global warming, as they do in other parts of the world. However, we do not find positive trends in the highest maximum temperature of the year in most of India since the 1970s (except spurious trends due to missing data). Decadal variability cannot explain this, but both increased air pollution with aerosols blocking sunlight and increased irrigation leading to evaporative cooling have counteracted the effect of greenhouse gases up to now. Current climate models do not represent these processes well and hence cannot be used to attribute heat waves in this area. The health effects of heat are often described better by a combination of temperature and humidity, such as a heat index or wet bulb temperature. Due to the increase in humidity from irrigation and higher sea surface temperatures (SSTs), these indices have increased over the last decades even when extreme temperatures have not. The extreme air pollution also exacerbates the health impacts of heat. From these factors it follows that, from a health impact point of view, the severity of heat waves has increased in India. For the next decades we expect the trend due to global warming to continue but the surface cooling effect of aerosols to diminish as air quality controls are implemented. The expansion of irrigation will likely continue, though at a slower pace, mitigating this trend somewhat. Humidity will probably continue to rise. The combination will result in a strong rise in the temperature of heat waves. The high humidity will make health effects worse, whereas decreased air pollution would decrease the impacts.

Effects of Ocean Acidification and Temperature Increases on the Photosynthesis of Tropical Reef Calcified Macroalgae

PubMed Central

Pereira, Cristiano Macedo; Duarte, Gustavo; Horta, Paulo Antunes; e Castro, Clovis Barreira; Barufi, José Bonomi; Pereira, Sonia Maria Barreto

2016-01-01

Climate change is a global phenomenon that is considered an important threat to marine ecosystems. Ocean acidification and increased seawater temperatures are among the consequences of this phenomenon. The comprehension of the effects of these alterations on marine organisms, in particular on calcified macroalgae, is still modest despite its great importance. There are evidences that macroalgae inhabiting highly variable environments are relatively resilient to such changes. Thus, the aim of this study was to evaluate experimentally the effects of CO2-driven ocean acidification and temperature rises on the photosynthesis of calcified macroalgae inhabiting the intertidal region, a highly variable environment. The experiments were performed in a reef mesocosm in a tropical region on the Brazilian coast, using three species of frondose calcifying macroalgae (Halimeda cuneata, Padina gymnospora, and Tricleocarpa cylindrica) and crustose coralline algae. The acidification experiment consisted of three treatments with pH levels below those occurring in the region (-0.3, -0.6, -0.9). For the temperature experiment, three temperature levels above those occurring naturally in the region (+1, +2, +4°C) were determined. The results of the acidification experiment indicate an increase on the optimum quantum yield by T. cylindrica and a decline of this parameter by coralline algae, although both only occurred at the extreme acidification treatment (-0.9). The energy dissipation mechanisms of these algae were also altered at this extreme condition. Significant effects of the temperature experiment were limited to an enhancement of the photosynthetic performance by H. cuneata although only at a modest temperature increase (+1°C). In general, the results indicate a possible photosynthetic adaptation and/or acclimation of the studied macroalgae to the expected future ocean acidification and temperature rises, as separate factors. Such relative resilience may be a result of the highly variable environment they inhabit. PMID:27158820

Making the case for high temperature low sag (htls) overhead transmission line conductors

NASA Astrophysics Data System (ADS)

Banerjee, Koustubh

The future grid will face challenges to meet an increased power demand by the consumers. Various solutions were studied to address this issue. One alternative to realize increased power flow in the grid is to use High Temperature Low Sag (HTLS) since it fulfills essential criteria of less sag and good material performance with temperature. HTLS conductors like Aluminum Conductor Composite Reinforced (ACCR) and Aluminum Conductor Carbon Composite (ACCC) are expected to face high operating temperatures of 150-200 degree Celsius in order to achieve the desired increased power flow. Therefore, it is imperative to characterize the material performance of these conductors with temperature. The work presented in this thesis addresses the characterization of carbon composite core based and metal matrix core based HTLS conductors. The thesis focuses on the study of variation of tensile strength of the carbon composite core with temperature and the level of temperature rise of the HTLS conductors due to fault currents cleared by backup protection. In this thesis, Dynamic Mechanical Analysis (DMA) was used to quantify the loss in storage modulus of carbon composite cores with temperature. It has been previously shown in literature that storage modulus is correlated to the tensile strength of the composite. Current temperature relationships of HTLS conductors were determined using the IEEE 738-2006 standard. Temperature rise of these conductors due to fault currents were also simulated. All simulations were performed using Microsoft Visual C++ suite. Tensile testing of metal matrix core was also performed. Results of DMA on carbon composite cores show that the storage modulus, hence tensile strength, decreases rapidly in the temperature range of intended use. DMA on composite cores subjected to heat treatment were conducted to investigate any changes in the variation of storage modulus curves. The experiments also indicates that carbon composites cores subjected to temperatures at or above 250 degree Celsius can cause permanent loss of mechanical properties including tensile strength. The fault current temperature analysis of carbon composite based conductors reveal that fault currents eventually cleared by backup protection in the event of primary protection failure can cause damage to fiber matrix interface.

Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

PubMed

Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

2011-06-15

The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour. Copyright © 2011 Elsevier B.V. All rights reserved.

Diminished Wastewater Treatment: Evaluation of Septic System Performance Under a Climate Change Scenario

NASA Astrophysics Data System (ADS)

Cooper, J.; Loomis, G.; Kalen, D.; Boving, T. B.; Morales, I.; Amador, J.

2015-12-01

The effects of climate change are expected to reduce the ability of soil-based onsite wastewater treatment systems (OWTS), to treat domestic wastewater. In the northeastern U.S., the projected increase in atmospheric temperature, elevation of water tables from rising sea levels, and heightened precipitation will reduce the volume of unsaturated soil and oxygen available for treatment. Incomplete removal of contaminants may lead to transport of pathogens, nutrients, and biochemical oxygen demand (BOD) to groundwater, increasing the risk to public health and likelihood of eutrophying aquatic ecosystems. Advanced OWTS, which include pre-treatment steps and provide unsaturated drainfields of greater volume relative to conventional OWTS, are expected to be more resilient to climate change. We used intact soil mesocosms to quantify water quality functions for two advanced shallow narrow drainfield types and a conventional drainfield under a current climate scenario and a moderate climate change scenario of 30 cm rise in water table and 5°C increase in soil temperature. While no fecal coliform bacteria (FCB) was released under the current climate scenario, up to 109 CFU FCB/mL (conventional) and up to 20 CFU FCB/mL (shallow narrow) were released under the climate change scenario. Total P removal rates dropped from 100% to 54% (conventional) and 71% (shallow narrow) under the climate change scenario. Total N removal averaged 17% under both climate scenarios in the conventional, but dropped from 5.4% to 0% in the shallow narrow under the climate change scenario, with additional leaching of N in excess of inputs indicating release of previously held N. No significant difference was observed between scenarios for BOD removal. The initial data indicate that while advanced OWTS retain more function under the climate change scenario, all three drainfield types experience some diminished treatment capacity.

Laser all-ceramic crown removal and pulpal temperature--a laboratory proof-of-principle study.

PubMed

Rechmann, P; Buu, N C H; Rechmann, B M T; Finzen, F C

2015-11-01

The objective of this proof-of-principle laboratory pilot study was to evaluate the temperature increase in the pulp chamber in a worst case scenario during Er:YAG laser debonding of all-ceramic crowns. Twenty extracted molars were prepared to receive all-ceramic IPS E.max CAD full contour crowns. The crowns were bonded to the teeth with Ivoclar Multilink Automix. Times for laser debonding and temperature rise in the pulp chamber using micro-thermocouples were measured. The Er:YAG was used with 560 mJ/pulse. The irradiation was applied at a distance of 5 mm from the crown surface. Additional air-water spray for cooling was utilized. Each all-ceramic crown was successfully laser debonded with an average debonding time of 135 ± 35 s. No crown fractured, and no damage to the underlying dentin was detected. The bonding cement deteriorated, but no carbonization at the dentin/cement interface occurred. The temperature rise in the pulp chamber averaged 5.4° ± 2.2 °C. During 8 out of the 20 crown removals, the temperature rise exceeded 5.5 °C, lasting 5 to 43 s (average 18.8 ± 11.6 s). A temperature rise of 11.5 °C occurred only once, while seven times the temperature rise was limited to 6.8 ± 0.5 °C. Temperature rises above 5.5 °C occurred only when the laser was applied from one side and additional cooling from the side opposite the irradiation. Er:YAG laser energy can successfully be used to efficiently debond all-ceramic crowns from natural teeth. Temperature rises exceeding 5.5 °C only occur when an additional air/water cooling from a dental syringe is inaccurately directed. To avoid possible thermal damage and to allow further heat diffusion, clinically temperature-reduced water might be applied.

Influence trend of temperature distribution in skin tissue generated by different exposure dose pulse laser

NASA Astrophysics Data System (ADS)

Shan, Ning; Wang, Zhijing; Liu, Xia

2014-11-01

Laser is widely applied in military and medicine fields because of its excellent capability. In order to effectively defend excess damage by laser, the thermal processing theory of skin tissue generated by laser should be carried out. The heating rate and thermal damage area should be studied. The mathematics model of bio-tissue heat transfer that is irradiated by laser is analyzed. And boundary conditions of bio-tissue are discussed. Three layer FEM grid model of bio-tissue is established. The temperature rising inducing by pulse laser in the tissue is modeled numerically by adopting ANSYS software. The changing trend of temperature in the tissue is imitated and studied under the conditions of different exposure dose pulse laser. The results show that temperature rising in the tissue depends on the parameters of pulse laser largely. In the same conditions, the pulse width of laser is smaller and its instant power is higher. And temperature rising effect in the tissue is very clear. On the contrary, temperature rising effect in the tissue is lower. The cooling time inducing by temperature rising effect in the tissue is longer along with pulse separation of laser is bigger. And the temperature difference is bigger in the pulse period.

Igniter adapter-to-igniter chamber deflection test

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Testing was performed to determine the maximum RSRM igniter adapter-to-igniter chamber joint deflection at the crown of the inner joint primary seal. The deflection data was gathered to support igniter inner joint gasket resiliency predictions which led to launch commit criteria temperature determinations. The proximity (deflection) gage holes for the first test (Test No. 1) were incorrectly located; therefore, the test was declared a non-test. Prior to Test No. 2, test article configuration was modified with the correct proximity gage locations. Deflection data were successfully acquired during Test No. 2. However, the proximity gage deflection measurements were adversely affected by temperature increases. Deflections measured after the temperature rise at the proximity gages were considered unreliable. An analysis was performed to predict the maximum deflections based on the reliable data measured before the detectable temperature rise. Deflections to the primary seal crown location were adjusted to correspond to the time of maximum expected operating pressure (2,159 psi) to account for proximity gage bias, and to account for maximum attach and special bolt relaxation. The maximum joint deflection for the igniter inner joint at the crown of the primary seal, accounting for all significant correction factors, was 0.0031 in. (3.1 mil). Since the predicted (0.003 in.) and tested maximum deflection values were sufficiently close, the launch commit criteria was not changed as a result of this test. Data from this test should be used to determine if the igniter inner joint gasket seals are capable of maintaining sealing capability at a joint displacement of (1.4) x (0.0031 in.) = 0.00434 inches. Additional testing should be performed to increase the database on igniter deflections and address launch commit criteria temperatures.

Beyond just sea-level rise: considering macroclimatic drivers within coastal wetland vulnerability assessments to climate change.

PubMed

Osland, Michael J; Enwright, Nicholas M; Day, Richard H; Gabler, Christopher A; Stagg, Camille L; Grace, James B

2016-01-01

Due to their position at the land-sea interface, coastal wetlands are vulnerable to many aspects of climate change. However, climate change vulnerability assessments for coastal wetlands generally focus solely on sea-level rise without considering the effects of other facets of climate change. Across the globe and in all ecosystems, macroclimatic drivers (e.g., temperature and rainfall regimes) greatly influence ecosystem structure and function. Macroclimatic drivers have been the focus of climate change-related threat evaluations for terrestrial ecosystems, but largely ignored for coastal wetlands. In some coastal wetlands, changing macroclimatic conditions are expected to result in foundation plant species replacement, which would affect the supply of certain ecosystem goods and services and could affect ecosystem resilience. As examples, we highlight several ecological transition zones where small changes in macroclimatic conditions would result in comparatively large changes in coastal wetland ecosystem structure and function. Our intent in this communication is not to minimize the importance of sea-level rise. Rather, our overarching aim is to illustrate the need to also consider macroclimatic drivers within vulnerability assessments for coastal wetlands. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Temperature dependence of water-water and ion-water correlations in bulk water and electrolyte solutions probed by femtosecond elastic second harmonic scattering

NASA Astrophysics Data System (ADS)

Chen, Yixing; Dupertuis, Nathan; Okur, Halil I.; Roke, Sylvie

2018-06-01

The temperature dependence of the femtosecond elastic second harmonic scattering (fs-ESHS) response of bulk light and heavy water and their electrolyte solutions is presented. We observe clear temperature dependent changes in the hydrogen (H)-bond network of water that show a decrease in the orientational order of water with increasing temperature. Although D2O has a more structured H-bond network (giving rise to more fs-ESHS intensity), the relative temperature dependence is larger in H2O. The changes are interpreted in terms of the symmetry of H-bonds and are indicators of nuclear quantum effects. Increasing the temperature in electrolyte solutions decreases the influence of the total electrostatic field from ions on the water-water correlations, as expected from Debye-Hückel theory, since the Debye length becomes longer. The effects are, however, 1.9 times (6.3 times) larger than those predicted for H2O (D2O). Since fs-ESHS responses can be computed from known molecular coordinates, our observations provide a unique opportunity to refine quantum mechanical models of water.

ESTIMATING RISK TO CALIFORNIA ENERGY INFRASTRUCTURE FROM PROJECTED CLIMATE CHANGE

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

Sathaye, Jayant; Dale, Larry; Larsen, Peter

2011-06-22

This report outlines the results of a study of the impact of climate change on the energy infrastructure of California and the San Francisco Bay region, including impacts on power plant generation; transmission line and substation capacity during heat spells; wildfires near transmission lines; sea level encroachment upon power plants, substations, and natural gas facilities; and peak electrical demand. Some end-of-century impacts were projected:Expected warming will decrease gas-fired generator efficiency. The maximum statewide coincident loss is projected at 10.3 gigawatts (with current power plant infrastructure and population), an increase of 6.2 percent over current temperature-induced losses. By the end ofmore » the century, electricity demand for almost all summer days is expected to exceed the current ninetieth percentile per-capita peak load. As much as 21 percent growth is expected in ninetieth percentile peak demand (per-capita, exclusive of population growth). When generator losses are included in the demand, the ninetieth percentile peaks may increase up to 25 percent. As the climate warms, California's peak supply capacity will need to grow faster than the population.Substation capacity is projected to decrease an average of 2.7 percent. A 5C (9F) air temperature increase (the average increase predicted for hot days in August) will diminish the capacity of a fully-loaded transmission line by an average of 7.5 percent.The potential exposure of transmission lines to wildfire is expected to increase with time. We have identified some lines whose probability of exposure to fire are expected to increase by as much as 40 percent. Up to 25 coastal power plants and 86 substations are at risk of flooding (or partial flooding) due to sea level rise.« less

An in-vitro study to compare the temperature rise in the pulp chamber by direct method using three different provisional restorative materials.

PubMed

Piplani, Ankita; Suresh Sajjan, M C; Ramaraju, A V; Tanwani, Tushar; Sushma, G; Ganathipathi, G; Jagdish, K; Agrawal, Anil

2016-01-01

The provisional restorative materials in fixed prosthodontics are basically bis-GMA resins which releases exothermic temperature while polymerization which can damage the pulp. Intrapulpal temperature exceeding 42.5°C found to result in irreversible damage to the pulp. The remaining thickness of dentine after tooth preparation control the conduction of heat released by the resins. (1) To quantify the temperature changes in the pulp chamber using different provisional restorative materials. (2) To evaluate the peak temperature time of different materials used. (3) To compare the intrapulpal temperature changes with a variation in the width of the finish line. Two intact mandibular molars were selected and designated as Specimen A and B. Tooth preparation was done to prepare a finish line of 1.2 mm and 1 mm width, respectively. Three provisional restorative materials were considered and they were grouped as Group I-Cool temp, Group II-Protemp-4, Group III-Integrity. A J thermocouple probe was placed into the pulp chamber to determine the rise in temperature. The temperature was recorded during polymerization at 30-s intervals until the peak temperature was reached. The same procedure was repeated for fabricating remaining provisional crowns. A total of 45 provisional crowns were fabricated for each specimen. Kruskal-Wallis test revealed that there was a significant difference in the temperature changes associated with the provisional restorative materials used. All the three provisional restorative materials were compared for 1.2 mm and 1 mm wide finish line. Integrity produced the highest temperature rise and the maximum temperature recorded was 40.2°C in 1.2 mm wide finish line. However, for a 1 mm wide finish line, Protemp-4 produced the highest temperature rise and the maximum temperature recorded was 40.3°C. It was observed that peak temperatures with Specimen B were more when compared with Specimen A. Cool temp showed least temperature rise in the pulp chamber. The order of rise in intrapulpal temperature in tested provisional materials using direct technique would be Cool temp, Integrity, and Protemp-4.

Impact of Fast Charging on Life of EV Batteries; NREL (National Renewable Energy Laboratory)

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

Neubauer, Jeremy; Wood, Eric; Burton, Evan

Installation of fast charging infrastructure is considered by many as one of potential solutions to increase the utility and range of electric vehicles (EVs). This is expected to reduce the range anxiety of drivers of EVs and thus increase their market penetration. Level 1 and 2 charging in homes and workplaces is expected to contribute to the majority of miles driven by EVs. However, a small percentage of urban driving and most of inter-city driving could be only achieved by a fast-charging network. DC fast charging at 50 kW, 100 kW, 120 kW compared to level 1 (3.3 kW) andmore » level 2 (6.6 kW) results in high-current charging that can adversely impact the life of the battery. In the last couple of years, we have investigated the impact of higher current rates in batteries and potential of higher temperatures and thus lower service life. Using mathematical models, we investigated the temperature increase of batteries due to higher heat generation during fast charge and have found that this could lead to higher temperatures. We compared our models with data from other national laboratories both for fine-tuning and calibration. We found that the incremental temperature rise of batteries during 1C to 3C fast charging may reduce the practical life of the batteries by less than 10% over 10 to 15 years of vehicle ownership. We also found that thermal management of batteries is needed for fast charging to prevent high temperature excursions leading to unsafe conditions.« less

Physiological Adjustments of Leaf Respiration to Atmospheric Warming in Betula alleghaniensis and Quercus rubra

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

Vollmar, A.; Gunderson, C.

2006-01-01

Global air temperatures are predicted to rise 1° to 4.5° Celsius by the year 2100. This climatic change is expected to have a great effect on the succession and migration of temperate deciduous forest species. Most physiologically based models of forest response to climatic change focus on the ecosystems as a whole instead of on individual tree species, assuming that the effects of warming on respiration are generally the same for each species, and that processes can not adjust to a changing climate. Experimental data suggest that physiological adjustments are possible, but there is a lack of data in deciduousmore » species. In order to correctly model the effects of climate change on temperate species, species-specific respiration acclimation (adjustment) to rising temperatures is being determined in this experiment. Two temperate deciduous tree species Betula alleghaniensis (BA) and Quercus rubra (QR) were grown over a span of four years in open-top chambers and subjected to two different temperature treatments; ambient and ambient plus 4° Celsius (E4). Between 0530 hours and 1100 hours, respiration was measured over a range of leaf temperatures on several comparable, fully expanded leaves in each treatment. Circular punches were taken from the leaves and dried at 60°C to determine leaf mass per area (LMA). Respiration rates at a common temperature decreased by 15-18% in both species, and the entire resperation versus temperature curve shifted by at least 4°C, indicating a large degree of physiological acclimation. Foliar mass per area decreased with increasing growth temperature for both species. It can be concluded that there is a relationship between leaf respiration and foliar mass as it relates to respiratory acclimation, and that these two species had similar patterns of adjustment to warming.« less

Bangladesh to prepare for rise in gas demand

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

Not Available

1992-06-01

Bangladesh is moving to expand its natural gas infrastructure in response to rising domestic demand. This paper reports that Bangladesh natural gas demand is expected to rise to 700-850 MMcfd in the next few years from the current level of about 500 MMcfd, the Prime Minister Khaleda Zia.

Impact of flows on ion temperatures inferred from neutron spectra in asymmetrically driven OMEGA DT implosions

NASA Astrophysics Data System (ADS)

Gatu Johnson, M.; Frenje, J.; Lahmann, B.; Seguin, F.; Petrasso, R.; Appelbe, B.; Chittenden, J.; Walsh, C.; Delettrez, J.; Igumenshchev, I.; Knauer, J. P.; Glebov, V. Yu.; Forrest, C.; Grimble, W.; Marshall, F.; Michel, T.; Stoeckl, C.; Haines, B. M.; Zylstra, A. B.

2017-10-01

Ion temperatures (Tion) in Inertial Confinement Fusion (ICF) experiments have traditionally been inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn, expected to arise due to asymmetries imposed by e.g. engineering features or drive non-uniformity, also impacts broadening and may lead to artificially inflated ``Tion'' values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured Tion, as observed in OMEGA cryogenic DT implosions but not in similar experiments at the NIF. In this presentation, we report on OMEGA experiments with intentional drive asymmetry designed for testing the ability to accurately predict and measure line-of-sight differences in apparent Tion due to low-mode asymmetry-seeded flows. The measurements are contrasted to CHIMERA, RAGE and ASTER simulations, providing insight into implosion dynamics and the relative importance of laser drive non-uniformity, stalk and offset as sources of asymmetry. The results highlight the complexity of hot-spot dynamics, which is a problem that must be mastered to achieve ICF ignition. This work was supported in part by the U.S. DOE, NLUF and LLE.

Temperature rise during polymerization of different cavity liners and composite resins

PubMed Central

Karatas, Ozcan; Turel, Verda; Bayindir, Yusuf Ziya

2015-01-01

Objective: The purpose of this study was to evaluate the thermal insulating properties of different light curing cavity liners and composite resins during light emitting diode (LED) curing. Materials and Methods: Sixty-four dentin discs, 1 mm thick and 8 mm in diameter, were prepared. Specimens were divided into four groups. Calcium hydroxide (Ca[OH]2), resin-modified glass ionomer cement, flowable composite and adhesive systems were applied to dentin discs according to the manufacturers’ instructions. The rise in temperature during polymerization with a LED curing unit (LCU) was measured using a K-type thermocouple connected to a data logger. Subsequently, all specimens were randomly divided into one of two groups. A silorane-based composite resin and a methacrylate-based composite resin were applied to the specimens. Temperature rise during polymerization of composite resins with LCU were then measured again. Data were analyzed using one-way ANOVA and post hoc Tukey analyses. Results: There were significant differences in temperature rise among the liners, adhesives, and composite resins (P < 0.05). Silorane-based composite resin exhibited significantly greater temperature rises than methacrylate-based resin (P < 0.05). The smallest temperature rises were observed in Ca(OH)2 specimens. Conclusion: Thermal insulating properties of different restorative materials are important factors in pulp health. Bonding agents alone are not sufficient to protect pulp from thermal stimuli throughout curing. PMID:26751112

Effect of specific pathways to 1.5°C global warming on the contribution of Greenland to sea level rise

NASA Astrophysics Data System (ADS)

Humbert, A.; Rückamp, M.; Falk, U.; Frieler, K.

2017-12-01

Sea level rise associated with changing climate is expected to pose a major challenge for societies. Here, we estimate the future contribution of the Greenland ice sheet (GrIS) to sea level change in terms of different emission scenarios. We investigate the effect of different pathways of global warming on the dynamics and mass balance of the GrIS with a focus on scenarios in line with limiting global warming to 2.0° or even 1.5° by the end of 2100 (Paris Agreement). We particularly address the issue of peak and decline scenarios temporarily exceeding a given temperature limit. This kind of overshooting might have strong effects on the evolution of the GrIS. Furthermore, we investigate the long-term effects of different levels of climate change to estimate the threshold for stabilizing the GrIS. For modeling the flow dynamics and future evolution of the GrIS, we apply the thermo-mechanical coupled Ice Sheet System Model (ISSM). The model is forced with anomalies for temperature and surface mass balance derived from different GCM data from the CMIP5 RCP2.6 scenario provided from the ISIMIP2b project. In order to obtain these anomalies from the GCM data, a surface energy balance model is applied.

Enabling fast charging – Battery thermal considerations

DOE PAGES

Keyser, Matthew; Pesaran, Ahmad; Li, Qibo; ...

2017-10-23

Battery thermal barriers are reviewed with regards to extreme fast charging. Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell,more » the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today’s market. Here, thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.« less

Prompt isothermal decay of thermoluminescence in an apatite exhibiting strong anomalous fading

NASA Astrophysics Data System (ADS)

Sfampa, I. K.; Polymeris, G. S.; Tsirliganis, N. C.; Pagonis, V.; Kitis, G.

2014-02-01

Anomalous fading (AF) is one of the most serious drawbacks in thermoluminescence (TL) and optically stimulated luminescence (OSL) dating. In the present work the isothermal decay of TL signals from Durango apatite is studied for temperatures located on the rising part of the main TL peak. This material is known to exhibit strong AF phenomena, and its isothermal TL decay properties have not been studied previously. The experimental results show that the characteristic decay time of the isothermal signal does not depend of the temperature, and that this signal does not exhibit the strong temperature dependence expected from conventional TL kinetic theories. This is further direct experimental evidence for the possible presence of tunneling phenomena in this material. The isothermal decay curves are analyzed and discussed within the framework of conventional theories of TL, as well as within the context of a recently developed tunneling kinetic model for random distributions of electron-hole pairs in luminescent materials.

Electrical Characterization of the RCA CDP1822SD Random Access Memory, Volume 1, Appendix a

NASA Technical Reports Server (NTRS)

Klute, A.

1979-01-01

Electrical characteristization tests were performed on 35 RCA CDP1822SD, 256-by-4-bit, CMOS, random access memories. The tests included three functional tests, AC and DC parametric tests, a series of schmoo plots, rise/fall time screening, and a data retention test. All tests were performed on an automated IC test system with temperatures controlled by a thermal airstream unit. All the functional tests, the data retention test, and the AC and DC parametric tests were performed at ambient temperatures of 25 C, -20 C, -55 C, 85 C, and 125 C. The schmoo plots were performed at ambient temperatures of 25 C, -55 C, and 125 C. The data retention test was performed at 25 C. Five devices failed one or more functional tests and four of these devices failed to meet the expected limits of a number of AC parametric tests. Some of the schmoo plots indicated a small degree of interaction between parameters.

Enabling fast charging – Battery thermal considerations

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

Keyser, Matthew; Pesaran, Ahmad; Li, Qibo

Battery thermal barriers are reviewed with regards to extreme fast charging. Present-day thermal management systems for battery electric vehicles are inadequate in limiting the maximum temperature rise of the battery during extreme fast charging. If the battery thermal management system is not designed correctly, the temperature of the cells could reach abuse temperatures and potentially send the cells into thermal runaway. Furthermore, the cell and battery interconnect design needs to be improved to meet the lifetime expectations of the consumer. Each of these aspects is explored and addressed as well as outlining where the heat is generated in a cell,more » the efficiencies of power and energy cells, and what type of battery thermal management solutions are available in today’s market. Here, thermal management is not a limiting condition with regard to extreme fast charging, but many factors need to be addressed especially for future high specific energy density cells to meet U.S. Department of Energy cost and volume goals.« less

Numerical modeling of heat and mass transfer in the human eye under millimeter wave exposure.

PubMed

Karampatzakis, Andreas; Samaras, Theodoros

2013-05-01

Human exposure to millimeter wave (MMW) radiation is expected to increase in the next several years. In this work, we present a thermal model of the human eye under MMW illumination. The model takes into account the fluid dynamics of the aqueous humor and predicts a frequency-dependent reversal of its flow that also depends on the incident power density. The calculated maximum fluid velocity in the anterior chamber and the temperature rise at the corneal apex are reported for frequencies from 40 to 100 GHz and different values of incident power density. Copyright © 2013 Wiley Periodicals, Inc.

KSC-02pd1856

NASA Image and Video Library

2002-12-05

KENNEDY SPACE CENTER, FLA. - Stephen Ezell, meteorological systems operator at Weather Station A, Cape Canaveral Air Force Station, walks out with a weather balloon that he will release. Such balloons are released twice a day. The package in Ezell's hand is a radio sonde that collects temperature and humidity data as the balloon rises. The data is released to agencies nationwide, including the 45th Space Wing which uses the data for its daily weather reports. The weather station provides additional data to NASA for launches - releasing 12 balloons in eight hours prior to liftoff - and landings - releasing 5 balloons in six and a half hours before expected touchdown.

KSC-02pd1860

NASA Image and Video Library

2002-12-05

KENNEDY SPACE CENTER, FLA. - At Weather Station A, Cape Canaveral Air Force Station, Judy Kelley, supervisor of Meteorology Operations, and Stephen Ezell, meteorological systems operator, get ready to release a weather balloon. Such balloons are released twice a day. The package at the bottom is a radio sonde that collects temperature and humidity data as the balloon rises. The data is released to agencies nationwide, including the 45th Space Wing, which uses the data for its daily weather reports. The weather station provides additional data to NASA for launches -- releasing 12 balloons in eight hours prior to liftoff - and landings - releasing 5 balloons in six and a half hours before expected touchdown.

Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

USGS Publications Warehouse

Kirwan, M.L.; Blum, L.K.

2011-01-01

Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find that organic decomposition rates increase by about 12% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, twice as high as the response of salt marsh productivity to temperature warming, and roughly equivalent to the productivity response associated with elevated CO2 in C3 marsh plants. Therefore, enhanced CO2 and warmer temperatures may actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between climate, sea level rise, and carbon emissions in coastal environments.

Altered nutrition during hot droughts will impair forest functions in the future

NASA Astrophysics Data System (ADS)

Grossiord, C.; Gessler, A.; Reed, S.; Dickman, L. T.; Collins, A.; Schönbeck, L.; Sevanto, S.; Vilagrosa, A.; McDowell, N. G.

2017-12-01

Rising greenhouse gas emissions will increase atmospheric temperature globally and alter hydrological cycles resulting in more extreme and recurrent droughts in the coming century. Nutrition is a key component affecting the vulnerability of forests to extreme climate. Models typically assume that global warming will enhance nitrogen cycling in terrestrial ecosystems and lead to improved plant functions. Drought on the other hand is expected to weaken the same processes, leading to a clear conflict and inability to predict how nutrition and plant functions will be impacted by a simultaneously warming and drying climate. We used a unique setup consisting of long-term manipulation of climate on mature trees to examine how individual vs. combined warming and drought would alter soil N cycling and tree functions. The site consists of the longest record of tree responses to experimental warming and precipitation reduction in natural conditions.Changes in soil nitrogen cycling (e.g. microbial activity, nitrification and ammonification rates, N concentration) occurred in response to the treatments. In addition, temperature rise and precipitation reduction altered the ability of trees to take up nitrogen and modified nitrogen allocation patterns between aboveground and belowground compartments. Although no additive effect of warming and drying were found for the two studied species, contrasting responses to warming and droughts were observed between the two functional types. Overall, our results show that higher temperature and reduced precipitation will alter the nutrition of forest ecosystems in the future with potentially large consequences for forest functions, structure and biodiversity.

A review of climate-driven mismatches between interdependent phenophases in terrestrial and aquatic ecosystems.

PubMed

Donnelly, Alison; Caffarra, Amelia; O'Neill, Bridget F

2011-11-01

Mismatches in phenology between mutually dependent species, resulting from climate change, can have far-reaching consequences throughout an ecosystem at both higher and lower trophic levels. Rising temperatures, due to climate warming, have resulted in advances in development and changes in behaviour of many organisms around the world. However, not all species or phenophases are responding to this increase in temperature at the same rate, thus creating a disruption to previously synchronised interdependent key life-cycle stages. Mismatches have been reported between plants and pollinators, predators and prey, and pests and hosts. Here, we review mismatches between interdependent phenophases at different trophic levels resulting from climate change. We categorized the studies into (1) terrestrial (natural and agricultural) ecosystems, and (2) aquatic (freshwater and marine) ecosystems. As expected, we found reports of 'winners' and 'losers' in each system, such as earlier emergence of prey enabling partial avoidance of predators, potential reductions in crop yield if herbivore pests emerge before their predators and possible declines in marine biodiversity due to disruption in plankton-fish phenologies. Furthermore, in the marine environment rising temperatures have resulted in synchrony in a previously mismatched prey and predator system, resulting in an abrupt population decline in the prey species. The examples reviewed suggest that more research into the complex interactions between species in terrestrial and aquatic ecosystems is necessary to make conclusive predictions of how climate warming may impact the fragile balances within ecosystems in future.

Influence of temperature on the single-stage ATAD process predicted by a thermal equilibrium model.

PubMed

Cheng, Jiehong; Zhu, Jun; Kong, Feng; Zhang, Chunyong

2015-06-01

Autothermal thermophilic aerobic digestion (ATAD) is a promising biological process that will produce an effluent satisfying the Class A requirements on pathogen control and land application. The thermophilic temperature in an ATAD reactor is one of the critical factors that can affect the satisfactory operation of the ATAD process. This paper established a thermal equilibrium model to predict the effect of variables on the auto-rising temperature in an ATAD system. The reactors with volumes smaller than 10 m(3) could not achieve temperatures higher than 45 °C under ambient temperature of -5 °C. The results showed that for small reactors, the reactor volume played a key role in promoting auto-rising temperature in the winter. Thermophilic temperature achieved in small ATAD reactors did not entirely depend on the heat release from biological activities during degrading organic matters in sludges, but was related to the ambient temperature. The ratios of surface area-to-effective volume less than 2.0 had less impact on the auto-rising temperature of an ATAD reactor. The influence of ambient temperature on the auto-rising reactor temperature decreased with increasing reactor volumes. High oxygen transfer efficiency had a significant influence on the internal temperature rise in an ATAD system, indicating that improving the oxygen transfer efficiency of aeration devices was a key factor to achieve a higher removal rate of volatile solids (VS) during the ATAD process operation. Compared with aeration using cold air, hot air demonstrated a significant effect on maintaining the internal temperature (usually 4-5 °C higher). Copyright © 2015 Elsevier Ltd. All rights reserved.

Sensitivity analysis of sea level rise contribution depending on external forcing: A case study of Victoria Land, East Antarctica.

NASA Astrophysics Data System (ADS)

Park, I. W.; Lee, S. H.; Lee, W. S.; Lee, C. K.; Lee, K. K.

2017-12-01

As global mean temperature increases, it affects increase in polar glacier melt and thermal expansion of sea, which contributed to global sea level rise. Unlike large sea level rise contributors in Western Antarctica (e. g. Pine island glacier, Thwaites glacier), glaciers in East Antarctica shows relatively stable and slow ice velocity. However, recent calving events related to increase of supraglacier lake in Nansen ice shelf arouse the questions in regards to future evolution of ice dynamics at Victoria Land, East Antarctica. Here, using Ice Sheet System Model (ISSM), a series of numerical simulations were carried out to investigate ice dynamics evolution (grounding line migration, ice velocity) and sea level rise contribution in response to external forcing conditions (surface mass balance, floating ice melting rate, and ice front retreat). In this study, we used control method to set ice dynamic properties (ice rigidity and friction coefficient) with shallow shelf approximation model and check each external forcing conditions contributing to sea level change. Before 50-year transient simulations were conducted based on changing surface mass balance, floating ice melting rate, and ice front retreat of Drygalski ice tongue and Nansen ice shelf, relaxation was performed for 10 years to reduce non-physical undulation and it was used as initial condition. The simulation results showed that sea level rise contribution were expected to be much less compared to other fast glaciers. Floating ice melting rate was most sensitive parameter to sea level rise, while ice front retreat of Drygalski tongue was negligible. The regional model will be further updated utilizing ice radar topography and measured floating ice melting rate.

Degradation Behavior of the HTS Bulk Magnet in Cryocooler System with Cyclic Temperature Variation

NASA Astrophysics Data System (ADS)

Okuno, K.; Sawa, K.; Iwasa, Y.

2006-03-01

This paper presents a change of magnetic flux trapped in the YBCO bulk magnet under thermal excursions. We have supposed a new cryocooler system for the high temperature superconducting(HTS) bulk magnet in which the thermal cycles are generated. From the past research, it was found that the trapped flux mainly deteriorated at the first temperature rise, but a large change of the trapped flux was not seen at the first temperature descent and following thermal cycles. Degradation of the trapped flux by the first temperature-rise was explained by using the bean model. Moreover we proposed the model which does not have a current distribution constant. In this paper, we examined a change of magnetic field in each part of the bulk in detail. In addition, we applied attention to the change of the trapped flux after the first temperature rise. Although there is no big change of the trapped flux after the first temperature-rise, it is decreasing slowly. This cause is considered as influence of the flux creep, but its decay is more rapid than usual.

Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

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

Lee, Ho-Young; Kang, In Man, E-mail: imkang@ee.knu.ac.kr; Shon, Chae-Hwa

2015-05-07

A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. Tomore » improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.« less

40 CFR 411.15 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. English units (lb/1,000 lb of product) TSS 0.005. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the...

40 CFR 411.15 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. English units (lb/1,000 lb of product) TSS 0.005. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the...

IN VITRO STUDY OF THE PULP CHAMBER TEMPERATURE RISE DURING LIGHT-ACTIVATED BLEACHING

PubMed Central

Carrasco, Thaise Graciele; Carrasco-Guerisoli, Laise Daniela; Fröner, Izabel Cristina

2008-01-01

This study evaluated in vitro the pulp chamber temperature rise induced by the light-activated dental bleaching technique using different light sources. The root portions of 78 extracted sound human mandibular incisors were sectioned approximately 2 mm below the cementoenamel junction. The root cavities of the crowns were enlarged to facilitate the correct placing of the sensor into the pulp chamber. Half of specimens (n=39) was assigned to receive a 35% hydrogen peroxide gel on the buccal surface and the other halt (n=39) not to receive the bleaching agent. Three groups (n=13) were formed for each condition (bleach or no bleach) according to the use of 3 light sources recommended for dental bleaching: a light-emitting diode (LED)-laser system, a LED unit and a conventional halogen light. The light sources were positioned perpendicular to the buccal surface at a distance of 5 mm and activated during 30 s. The differences between the initial and the highest temperature readings for each specimen were obtained, and, from the temperature changes, the means for each specimen and each group were calculated. The values of temperature rise were compared using Kruskal-Wallis test at 1% significance level. Temperature rise varied significantly depending on the light-curing unit, with statistically significant differences (p<0.01) among the groups. When the bleaching agent was not applied, the halogen light induced the highest temperature rise (2.38±0.66°C). The LED unit produced the lowest temperature increase (0.29±0.13°C); but there was no significant difference between LED unit and LED-laser system (0.35±0.15°C) (p>0.01). When the bleaching agent was applied, there were significant differences among groups (p<0.01): halogen light induced the highest temperature rise (1.41±0.64°C), and LED-laser system the lowest (0.33±0.12°C); however, there was no difference between LED-laser system and LED unit (0.44±0.11°C). LED and LED-laser system did not differ significantly from each other regardless the temperature rise occurred with or without bleaching agent application. It may be concluded that during light-activated tooth bleaching, with or without the bleaching agent, halogen light promoted higher pulp chamber temperature rise than LED unit and LED-laser system. The tested light-curing units provided increases in the pulp chamber temperature that were compatible with pulpal health. PMID:19089234

Historical Change of Equilibrium Water Temperature in Japan

NASA Astrophysics Data System (ADS)

Miyamoto, H.

2015-12-01

Changes in freshwater ecosystems due to a climate change have been great concern for sustainable river basin management both for water resources utilization and ecological conservation. However, their impact seems to be difficult to evaluate because of wide variety of basin characteristics along a river network both in nature and social environment. This presentation uses equilibrium water temperature as a simple criterion index for evaluating the long-term changes of stream thermal environment due to the historical climate change in Japan. It examines, at first, the relationship between the equilibrium water temperature and the stream temperature observed for 7 years at a lower reach in the Ibo River, Japan. It analyzes, then, the seasonal and regional trends of the equilibrium water temperature change for the last 50 years at 133 meteorological station sites throughout Japan, discussing their rising or falling characteristics. The correlation analysis at the local reach of the Ibo River shows that the equilibrium water temperature has similar trend of change as the stream temperature. However, its value tends to be higher than the stream temperature in summer, while lower in winter. The onset of the higher equilibrium water temperature fluctuates annually from mid February to early April. This onset fluctuation at each spring could be influenced by the different amount of snow at the antecedent winter. The rising or falling trends of the equilibrium water temperature are analyzed both annually and seasonally through the regression analysis of the 133 sites in Japan. Consequently, the trends of the temperature change could be categorized by 12 patterns. As for the seasonal analysis, the results shows that there are many sites indicating the falling trend in spring and summer, and rising trends in autumn and winter. In particular, winter has the strong rising tendency throughout Japan. As for the regional analysis, the result illustrates the precise rationality; e.g., northern parts of Japan show the temperature fall in spring and the temperature rise in autumn, while the urbanized regions along the Pacific coastline indicate the temperature rise in all the four seasons.

Temperature Rise during Primer, Adhesive, and Composite Resin Photopolymerization of a Low-Shrinkage Composite Resin under Caries-Like Dentin Lesions

PubMed Central

Mousavinasab, Sayed-Mostafa; Khoroushi, Maryam; Moharreri, Mohammadreza

2012-01-01

Objective. This study evaluated temperature rise of low-shrinkage (LS) self-etch primer (P), LS self-etch adhesive (A), and P90 silorane-based composite resin systems, photopolymerized under normal and artificially demineralized dentin. Methods. Forty 1.5 mm-thick dentin discs were prepared from sound human molars, half of which were demineralized. Temperature rise was measured during photopolymerization using a K-type thermocouple under the discs: 10 s and 40 s irradiation of the discs (controls/groups 1 and 2); 10 s irradiation of primer (P), 10 s irradiation of adhesive (A), 40 s irradiation of P90 without P and A, and 40 s irradiation of P90 with P and A (groups 3 to 6, resp.). The samples were photopolymerized using an LED unit under 550 mW/cm2 light intensity. Data was analyzed using repeated measures ANOVA and paired-sample t-test (α = 0.05). Results. There were no significant differences in temperature rise means between the two dentin samples for each irradiation duration (P > 0.0001), with significant differences between the two irradiation durations (P > 0.0001). Temperature rise measured with 40 s irradiation was significantly higher than that of 10 s duration for undemineralized and demineralized dentin P < 0.0001). Conclusions. Light polymerization of P90 low-shrinkage composite resin resulted in temperature rise approaching threshold value under artificially demineralized and undemineralized dentin. PMID:23320185

Environmental temperature variation influences fitness trade-offs and tolerance in a fish-tapeworm association.

PubMed

Franke, Frederik; Armitage, Sophie A O; Kutzer, Megan A M; Kurtz, Joachim; Scharsack, Jörn P

2017-06-02

Increasing temperatures are predicted to strongly impact host-parasite interactions, but empirical tests are rare. Host species that are naturally exposed to a broad temperature spectrum offer the possibility to investigate the effects of elevated temperatures on hosts and parasites. Using three-spined sticklebacks, Gasterosteus aculeatus L., and tapeworms, Schistocephalus solidus (Müller, 1776), originating from a cold and a warm water site of a volcanic lake, we subjected sympatric and allopatric host-parasite combinations to cold and warm conditions in a fully crossed design. We predicted that warm temperatures would promote the development of the parasites, while the hosts might benefit from cooler temperatures. We further expected adaptations to the local temperature and mutual adaptations of local host-parasite pairs. Overall, S. solidus parasites grew faster at warm temperatures and stickleback hosts at cold temperatures. On a finer scale, we observed that parasites were able to exploit their hosts more efficiently at the parasite's temperature of origin. In contrast, host tolerance towards parasite infection was higher when sticklebacks were infected with parasites at the parasite's 'foreign' temperature. Cold-origin sticklebacks tended to grow faster and parasite infection induced a stronger immune response. Our results suggest that increasing environmental temperatures promote the parasite rather than the host and that host tolerance is dependent on the interaction between parasite infection and temperature. Sticklebacks might use tolerance mechanisms towards parasite infection in combination with their high plasticity towards temperature changes to cope with increasing parasite infection pressures and rising temperatures.

Study of the temperature rise induced by a focusing transducer with a wide aperture angle on biological tissue containing ribs

NASA Astrophysics Data System (ADS)

Xin, Wang; Jiexing, Lin; Xiaozhou, Liu; Jiehui, Liu; Xiufen, Gong

2016-04-01

We used the spheroidal beam equation to calculate the sound field created by focusing a transducer with a wide aperture angle to obtain the heat deposition, and then we used the Pennes bioheat equation to calculate the temperature field in biological tissue with ribs and to ascertain the effects of rib parameters on the temperature field. The results show that the location and the gap width between the ribs have a great influence on the axial and radial temperature rise of multilayer biological tissue. With a decreasing gap width, the location of the maximum temperature rise moves forward; as the ribs are closer to the transducer surface, the sound energy that passes through the gap between the ribs at the focus decreases, the maximum temperature rise decreases, and the location of the maximum temperature rise moves forward with the ribs. Project supported by the National Basic Research Program of China (Grant Nos. 2012CB921504 and 2011CB707902), the National Natural Science Foundation of China (Grant No. 11274166), the Fundamental Research Funds for the Central Universities, China (Grant No. 020414380001), the Fund from State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLA201401), China Postdoctoral Science Foundation (Grant No. 2013M531313), and the Priority Academic Program Development of Jiangsu Higher Education Institutions and SRF for ROCS, SEM.

Global mean sea-level rise in a world agreed upon in Paris

NASA Astrophysics Data System (ADS)

Bittermann, Klaus; Rahmstorf, Stefan; Kopp, Robert E.; Kemp, Andrew C.

2017-12-01

Although the 2015 Paris Agreement seeks to hold global average temperature to ‘well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels’, projections of global mean sea-level (GMSL) rise commonly focus on scenarios in which there is a high probability that warming exceeds 1.5 °C. Using a semi-empirical model, we project GMSL changes between now and 2150 CE under a suite of temperature scenarios that satisfy the Paris Agreement temperature targets. The projected magnitude and rate of GMSL rise varies among these low emissions scenarios. Stabilizing temperature at 1.5 °C instead of 2 °C above preindustrial reduces GMSL in 2150 CE by 17 cm (90% credible interval: 14-21 cm) and reduces peak rates of rise by 1.9 mm yr-1 (90% credible interval: 1.4-2.6 mm yr-1). Delaying the year of peak temperature has little long-term influence on GMSL, but does reduce the maximum rate of rise. Stabilizing at 2 °C in 2080 CE rather than 2030 CE reduces the peak rate by 2.7 mm yr-1 (90% credible interval: 2.0-4.0 mm yr-1).

46 CFR 164.008-4 - Test requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... thermocouples on the unexposed surface described in § 164.008-3(f)(2) will not rise more than 139 °C. (250 °F..., rise more than 225 °C. (405 °F.) above the initial temperature at the end of 15 minutes. When failure is due to excessive temperature rise on the joint, consideration will be given to alternate joint...

46 CFR 164.008-4 - Test requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... thermocouples on the unexposed surface described in § 164.008-3(f)(2) will not rise more than 139 °C. (250 °F..., rise more than 225 °C. (405 °F.) above the initial temperature at the end of 15 minutes. When failure is due to excessive temperature rise on the joint, consideration will be given to alternate joint...

How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet?

NASA Astrophysics Data System (ADS)

Applegate, Patrick J.; Keller, Klaus

2015-08-01

Albedo modification (AM) is sometimes characterized as a potential means of avoiding climate threshold responses, including large-scale ice sheet mass loss. Previous work has investigated the effects of AM on total sea-level rise over the present century, as well as AM’s ability to reduce long-term (≫103 yr) contributions to sea-level rise from the Greenland Ice Sheet (GIS). These studies have broken new ground, but neglect important feedbacks in the GIS system, or are silent on AM’s effectiveness over the short time scales that may be most relevant for decision-making (<103 yr). Here, we assess AM’s ability to reduce GIS sea-level contributions over decades to centuries, using a simplified ice sheet model. We drive this model using a business-as-usual base temperature forcing scenario, as well as scenarios that reflect AM-induced temperature stabilization or temperature drawdown. Our model results suggest that (i) AM produces substantial near-term reductions in the rate of GIS-driven sea-level rise. However, (ii) sea-level rise contributions from the GIS continue after AM begins. These continued sea level rise contributions persist for decades to centuries after temperature stabilization and temperature drawdown begin, unless AM begins in the next few decades. Moreover, (iii) any regrowth of the GIS is delayed by decades or centuries after temperature drawdown begins, and is slow compared to pre-AM rates of mass loss. Combined with recent work that suggests AM would not prevent mass loss from the West Antarctic Ice Sheet, our results provide a nuanced picture of AM’s possible effects on future sea-level rise.

Fabricating continuous electroconductive polyacrylonitrile fibers with thermosensitive property via wet-spinning

NASA Astrophysics Data System (ADS)

Liu, Wanwan; Jin, Yang; Wang, Yangyi; Ge, Mingqiao; Gao, Qiang

2017-12-01

In this work, conductive polyacrylonitrile (PAN) composite fiber with thermosensitive property was successfully prepared via wet-spinning. Thermochromic pigment (TCP) microsphere capsules were applied to manufacture color-changing fibers. Meanwhile, light-colored conductive whiskers (ATO@TiO2) were employed to endow polyacrylonitrile fibers with conductivity without prejudicing their thermosensitive property. Interestingly, unlike other conductive fibers in dark color, this kind of conductive composite fiber can be dyed by thermosensitive pigment. The obtained composite fiber containing 20 vol% ATO@TiO2 whiskers shows a resistivity of 105 Ω · cm and could generate heat by Joule heating when being applied under a certain voltage. The composite fiber shows a red color at room temperature, while the color of the composite fiber fades gradually and finally becomes white as temperature rise. This simple and cost-effective approach is expected to inspire more research into the applications of multifunctional conductive fibers.

Temperature changes in the pulp chamber during dentin ablation with Er:YAG laser

NASA Astrophysics Data System (ADS)

Zhang, Xianzeng; Zhao, Haibin; Zhan, Zhenlin; Guo, Wenqing; Xie, Shusen

2012-12-01

To examine the temperature changes in the pulp chamber during cavity preparation in dentin with the Er:YAG laser (2940 nm), a total 20 intact premolars teeth were divided into 4 groups for dentin ablation with different radiant exposures at 4Hz and 8Hz with and without water spray. A K-type thermocouple was used to monitor the temperature changes in pulp chamber during laser treatment. The total time of irradiation was 70 sec. the water spray rate was 3 mL/min. It showed that maximum temperature rise increases with the increasing of radiant exposure and pulse repetition rate and the additional water cooling during laser ablation can significantly reduce the temperature rise in pulp chamber which will benefit to avoid or reduce thermal damage to tooth structure and dental pulp. The highest rise of temperature in the pulp was achieved with 20 J/cm2 and 8 Hz (19.83°C ). For all sample without water spray, the rise of temperature was exceed 5 °C . In contrast, with water spray, the temperature rise in the pulp can be firmly controlled under 1°C. The results also indicated that ablation rate and efficiency can be enhanced by increasing the incident radiant exposure and pulse repetition rate, which simultaneously producing more heat accumulation in dental tissue and causing thermal damage to dental tissue. By applying an additional water spray, thermal damage can be significantly reduced in clinical application.

Trends in snowfall versus rainfall in the Western United States--Revisited

NASA Astrophysics Data System (ADS)

Dettinger, M. D.; Knowles, N.; Cayan, D. R.

2015-12-01

Knowles et al. (J. Climate, 2006) documented long-term (1949-2004) trends in precipitation form, with a smaller fraction of precipitation falling, in recent decades, on days with reported snow compared to days when no snow was reported (and when precipitation was presumably rain). This precipitation-amount-corrected trend was found at three-quarters of 261 cooperative weather stations across the region. The trends correlated with corresponding trends towards warmer winter air temperatures at the weather stations involved. An update of those analyses through the more recent period indicates that the overall swing towards less precipitation fraction occurring on snowy days has continued through the intervening years, with 21st Century rain/snow fractions remaining significantly higher than historical norms at most stations. The same data have also been used to develop site-specific statistical relations between precipitation form (snowy-day precipitation vs purely rainy day) and air temperatures by logistical regressions at over 200 stations across the West, to determine whether the general temperature trends mentioned above have, in fact, been large enough to explain the trending precipitation forms. That is, were the warming trends detected across the West large enough to actually raise temperatures above the local snow-rain thresholds at most stations? The regression relations show that the temperature at which half of the wet days have been snowy historically varies, from station to station, across a range from -2ºC to +4ºC. Thus at some stations winter storm temperatures would have to rise above about -2ºC to markedly impact precipitation forms, while at other stations, temperature had to rise above +4ºC. Nonetheless, observed temperature trends since 1950 have been sufficient to explain the observed regional precipitation-form trends. The fitted precipitation form-temperature relations also provide a basis for estimating precipitation forms in hydrological models and in climate-change projections across the region, allowing—for example—more geographically informed projections of precipitation-form changes under future climates. On the whole, though, the expected relations between warming trends and precipitation-form trends found by Knowles et al. (2006) continue to hold.

The Effect of Specimen Size on the Results of Concrete Adiabatic Temperature Rise Test with Commercially Available Equipment.

PubMed

Lee, Byung Jae; Bang, Jin Wook; Shin, Kyung Joon; Kim, Yun Yong

2014-12-08

In this study, adiabatic temperature rise tests depending on binder type and adiabatic specimen volume were performed, and the maximum adiabatic temperature rises and the reaction factors for each mix proportion were analyzed and suggested. The results indicated that the early strength low heat blended cement mixture had the lowest maximum adiabatic temperature rise ( Q ∞ ) and the ternary blended cement mixture had the lowest reaction factor ( r ). Also, Q and r varied depending on the adiabatic specimen volume even when the tests were conducted with a calorimeter, which satisfies the recommendations for adiabatic conditions. Test results show a correlation: the measurements from the 50 L specimens were consistently higher than those from the 6 L specimens. However, the Q ∞ and r values of the 30 L specimen were similar to those of the 50 L specimen. Based on the above correlation, the adiabatic temperature rise of the 50 L specimen could be predicted using the results of the 6 L and 30 L specimens. Therefore, it is thought that this correlation can be used for on-site concrete quality control and basic research.

Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

USGS Publications Warehouse

Kirwan, M.L.; Blum, L.K.

2011-01-01

Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find that organic decomposition rates increase by about 12% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, twice as high as the response of salt marsh productivity to temperature warming, and roughly equivalent to the productivity response associated with elevated CO2 in C3 marsh plants. Therefore, enhanced CO2 and warmer temperatures may actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between climate, sea level rise, and carbon emissions in coastal environments. ?? 2011 Author(s).

Human cadaver retina model for retinal heating during corneal surgery with a femtosecond laser

NASA Astrophysics Data System (ADS)

Sun, Hui; Fan, Zhongwei; Yun, Jin; Zhao, Tianzhuo; Yan, Ying; Kurtz, Ron M.; Juhasz, Tibor

2014-02-01

Femtosecond lasers are widely used in everyday clinical procedures to perform minimally invasive corneal refractive surgery. The intralase femtosecond laser (AMO Corp. Santa Ana, CA) is a common example of such a laser. In the present study a numerical simulation was developed to quantify the temperature rise in the retina during femtosecond intracorneal surgery. Also, ex-vivo retinal heating due to laser irradiation was measured with an infrared thermal camera (Fluke Corp. Everett, WA) as a validation of the simulation. A computer simulation was developed using Comsol Multiphysics to calculate the temperature rise in the cadaver retina during femtosecond laser corneal surgery. The simulation showed a temperature rise of less than 0.3 degrees for realistic pulse energies for the various repetition rates. Human cadaver retinas were irradiated with a 150 kHz Intralase femtosecond laser and the temperature rise was measured withan infrared thermal camera. Thermal camera measurements are in agreement with the simulation. During routine femtosecond laser corneal surgery with normal clinical parameters, the temperature rise is well beneath the threshold for retina damage. The simulation predictions are in agreement with thermal measurements providing a level of experimental validation.

Effect of temperature rise and hydrostatic pressure on microbending loss and refractive index change in double-coated optical fiber

NASA Astrophysics Data System (ADS)

Seraji, Faramarz E.; Toutian, Golnoosh

This paper presents an analysis of the effect of temperature rise and hydrostatic pressure on microbending loss, refractive index change, and stress components of a double-coated optical fiber by considering coating material parameters such as Young's modulus and the Poisson ratio. It is shown that, when temperature rises, the microbending loss and refractive index changes would decrease with increase of thickness of primary coating layer and will increase after passing through a minima. Increase of thickness of secondary coating layer causes the microbending loss and refractive index changes to decrease. We have shown that the temperature rise affecting the fiber makes the microbending loss and refractive index decrease, linearly. At a particular temperature, the microbending loss takes negative values, due to tensile pressure applied on the fiber. The increase of Young's modulus and the Poisson ratio of primary coating would lower the microbending loss and refractive index change whereas in the secondary coating layer, the condition reverses.

A comparison of root surface temperatures using different obturation heat sources.

PubMed

Lee, F S; Van Cura, J E; BeGole, E

1998-09-01

This study compared root surface temperatures produced during warm vertical obturation using the System B Heat Source (SB), the Touch 'n Heat device (TH), and a flame-heated carrier (FH). The root canals of 30 maxillary incisor, premolar, and mandibular incisor teeth were prepared; divided into three groups; and obturated using each heat source. A thermocouple placed 2 mm below the cementoenamel junction transferred the temperature rise on the external root surface to a digital thermometer. SB surface temperature rise was < 10 degrees C for all experimental teeth. TH temperature rise in maxillary incisors and premolars was < 10 degrees C; however, > 10 degrees C was observed for mandibular incisors. FH produced a > 10 degrees C surface temperature rise in all experimental teeth. The critical level of root surface heat required to produce irreversible bone damage is believed to be > 10 degrees C. The findings of this study suggest that warm vertical condensation with the SB should not damage supporting periradicular tissues. However, caution should be used with TH and FH on mandibular incisors.

Climate induced temperature effects on growth performance, fecundity and recruitment in marine fish: developing a hypothesis for cause and effect relationships in Atlantic cod ( Gadus morhua) and common eelpout ( Zoarces viviparus)

NASA Astrophysics Data System (ADS)

Pörtner, H. O.; Berdal, B.; Blust, R.; Brix, O.; Colosimo, A.; De Wachter, B.; Giuliani, A.; Johansen, T.; Fischer, T.; Knust, R.; Lannig, G.; Naevdal, G.; Nedenes, A.; Nyhammer, G.; Sartoris, F. J.; Serendero, I.; Sirabella, P.; Thorkildsen, S.; Zakhartsev, M.

2001-12-01

Effects of global warming on animal distribution and performance become visible in many marine ecosystems. The present study was designed to develop a concept for a cause and effect understanding with respect to temperature changes and to explain ecological findings based on physiological processes. The concept is based on a wide comparison of invertebrate and fish species with a special focus on recent data obtained in two model species of fish. These fish species are both characterized by northern and southern distribution limits in the North Atlantic: eelpout ( Zoarces viviparus), as a typical non-migrating inhabitant of the coastal zone and the cod ( Gadus morhua), as a typical inhabitant of the continental shelf with a high importance for fisheries. Mathematical modelling demonstrates a clear significant correlation between climate induced temperature fluctuations and the recruitment of cod stocks. Growth performance in cod is optimal at temperatures close to 10°C, regardless of the population investigated in a latitudinal cline. However, temperature specific growth rates decrease at higher latitudes. Also, fecundity is less in White Sea than in North and Baltic Sea cod or eelpout populations. These findings suggest that a cold-induced shift in energy budget occurs which is unfavorable for growth performance and fecundity. Thermal tolerance limits shift depending on latitude and are characterized by oxygen limitation at both low or high temperatures. Oxygen supply to tissues is optimized at low temperature by a shift in hemoglobin isoforms and oxygen binding properties to lower affinities and higher unloading potential. Protective stimulation of heat shock protein synthesis was not observed. According to a recent model of thermal tolerance the downward shift of tolerance limits during cold adaptation is associated with rising mitochondrial densities and, thus, aerobic capacity and performance in the cold, especially in eurythermal species. At the same time the costs of mitochondrial maintenance reflected by mitochondrial proton leakage should rise leaving a lower energy fraction for growth and reproduction. The preliminary conclusion can be drawn that warming will cause a northern shift of distribution limits for both species with a rise in growth performance and fecundity larger than expected from the Q 10 effect in the north and lower growth or even extinction of the species in the south. Such a shift may heavily affect fishing activities in the North Sea.

Effects of portland cement particle size on heat of hydration.

DOT National Transportation Integrated Search

2013-12-01

Following specification harmonization for portland cements, FDOT engineers reported signs of : deterioration in concrete elements due to temperature rise effects. One of the main factors that affect : concrete temperature rise potential is the heat g...

Climate change impacts on U.S. coastal and marine ecosystems

USGS Publications Warehouse

Scavia, Donald; Field, John C.; Boesch, Donald F.; Buddemeier, Robert W.; Burkett, Virginia; Cayan, Daniel R.; Fogarty, Michael; Harwell, Mark A.; Howarth, Robert W.; Mason, Curt; Reed, Denise J.; Royer, Thomas C.; Sallenger, Asbury H.; Titus, James G.

2002-01-01

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean temperatures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO2. Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO2 levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other organisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruction, invasive species, land and resource use, extreme natural events), which may lead to more significant consequences.

Flood Risk Due to Hurricane Flooding

NASA Astrophysics Data System (ADS)

Olivera, Francisco; Hsu, Chih-Hung; Irish, Jennifer

2015-04-01

In this study, we evaluated the expected economic losses caused by hurricane inundation. We used surge response functions, which are physics-based dimensionless scaling laws that give surge elevation as a function of the hurricane's parameters (i.e., central pressure, radius, forward speed, approach angle and landfall location) at specified locations along the coast. These locations were close enough to avoid significant changes in surge elevations between consecutive points, and distant enough to minimize calculations. The probability of occurrence of a surge elevation value at a given location was estimated using a joint probability distribution of the hurricane parameters. The surge elevation, at the shoreline, was assumed to project horizontally inland within a polygon of influence. Individual parcel damage was calculated based on flood water depth and damage vs. depth curves available for different building types from the HAZUS computer application developed by the Federal Emergency Management Agency (FEMA). Parcel data, including property value and building type, were obtained from the county appraisal district offices. The expected economic losses were calculated as the sum of the products of the estimated parcel damages and their probability of occurrence for the different storms considered. Anticipated changes for future climate scenarios were considered by accounting for projected hurricane intensification, as indicated by sea surface temperature rise, and sea level rise, which modify the probability distribution of hurricane central pressure and change the baseline of the damage calculation, respectively. Maps of expected economic losses have been developed for Corpus Christi in Texas, Gulfport in Mississippi and Panama City in Florida. Specifically, for Port Aransas, in the Corpus Christi area, it was found that the expected economic losses were in the range of 1% to 4% of the property value for current climate conditions, of 1% to 8% for the 2030's and of 1% to 14% for the 2080's.

Climate Change and Health Risks from Extreme Heat and Air Pollution in the Eastern United States

NASA Astrophysics Data System (ADS)

Limaye, V.; Vargo, J.; Harkey, M.; Holloway, T.; Meier, P.; Patz, J.

2013-12-01

Climate change is expected to exacerbate health risks from exposure to extreme heat and air pollution through both direct and indirect mechanisms. Directly, warmer ambient temperatures promote biogenic emissions of ozone precursors and favor the formation of ground-level ozone, while an anticipated increase in the frequency of stagnant air masses will allow fine particulates to accumulate. Indirectly, warmer summertime temperatures stimulate energy demand and exacerbate polluting emissions from the electricity sector. Thus, while technological adaptations such as air conditioning can reduce risks from exposures to extreme heat, they can trigger downstream damage to air quality and public health. Through an interdisciplinary modeling effort, we quantify the impacts of climate change on ambient temperatures, summer energy demand, air quality, and public health. The first phase of this work explores how climate change will directly impact the burden of heat-related mortality. Climatic patterns, demographic trends, and epidemiologic risk models suggest that populations in the eastern United States are likely to experience an increasing heat stress mortality burden in response to rising summertime air temperatures. We use North American Regional Climate Change Assessment Program modeling data to estimate mid-century 2-meter air temperatures and humidity across the eastern US from June-August, and quantify how long-term changes in actual and apparent temperatures from present-day will affect the annual burden of heat-related mortality across this region. With the US Environmental Protection Agency's Environmental Benefits Mapping and Analysis Program, we estimate health risks using concentration-response functions, which relate temperature increases to changes in annual mortality rates. We compare mid-century summertime temperature data, downscaled using the Weather Research and Forecasting model, to 2007 baseline temperatures at a 12 km resolution in order to estimate the number of annual excess deaths attributable to increased summer temperatures. Warmer average temperatures are expected to cause 173 additional deaths due to cardiovascular stress, while higher minimum temperatures will cause 67 additional deaths. This work particularly improves on the spatial resolution of published analyses of heat-related mortality in the US.

Effects of temperature on gene expression in embryos of the coral Montastraea faveolata

PubMed Central

2009-01-01

Background Coral reefs are expected to be severely impacted by rising seawater temperatures associated with climate change. This study used cDNA microarrays to investigate transcriptional effects of thermal stress in embryos of the coral Montastraea faveolata. Embryos were exposed to 27.5°C, 29.0°C, and 31.5°C directly after fertilization. Differences in gene expression were measured after 12 and 48 hours. Results Analysis of differentially expressed genes indicated that increased temperatures may lead to oxidative stress, apoptosis, and a structural reconfiguration of the cytoskeletal network. Metabolic processes were downregulated, and the action of histones and zinc finger-containing proteins may have played a role in the long-term regulation upon heat stress. Conclusions Embryos responded differently depending on exposure time and temperature level. Embryos showed expression of stress-related genes already at a temperature of 29.0°C, but seemed to be able to counteract the initial response over time. By contrast, embryos at 31.5°C displayed continuous expression of stress genes. The genes that played a role in the response to elevated temperatures consisted of both highly conserved and coral-specific genes. These genes might serve as a basis for research into coral-specific adaptations to stress responses and global climate change. PMID:20030803

40 CFR 411.25 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (maximum for any 1 day) Metric units (kg/kkg of dust leached) TSS 0.4. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. English units (lb/1,000 lb of dust leached) TSS 0.4. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range...

40 CFR 411.25 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (maximum for any 1 day) Metric units (kg/kkg of dust leached) TSS 0.4. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. English units (lb/1,000 lb of dust leached) TSS 0.4. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range...

Effects of climate change on water quality in the Yaquina ...

EPA Pesticide Factsheets

As part of a larger study to examine the effect of climate change (CC) on estuarine resources, we simulated the effect of rising sea level, alterations in river discharge, and increasing atmospheric temperatures on water quality in the Yaquina Estuary. Due to uncertainty in the effects of climate change, initial model simulations were performed for different steady river discharge rates that span the historical range in inflow, and for a range of increases in sea level and atmospheric temperature. Model simulations suggest that in the central portion of the estuary (19 km from mouth), a 60-cm increase in sea level will result in a 2-3 psu change in salinity across a broad range of river discharges. For the oligohaline portion of the estuary, salinity increases associated with a rise in sea level of 60 cm are only apparent at low river discharge rates (< 50 m3 s-1). Simulations suggest that the water temperatures near the mouth of the estuary will decrease due to rising sea level, while water temperatures in upriver portions of the estuary will increase due to rising atmospheric temperatures. We present results which demonstrate how the interaction of changes in river discharge, rising sea level, and atmospheric temperature associated with climate change produce non-linear patterns in the response of estuarine salinity and temperature, which vary with location inside the estuary and season. We also will discuss the importance of presenting results in a mann

Paris Agreement on Climate Change: A Booster to Enable Sustainable Global Development and Beyond.

PubMed

Bhore, Subhash Janardhan

2016-11-14

The global warming and its adverse effects on the atmosphere, the biosphere, the lithosphere, and the hydrosphere are obvious. Based on this fact, the international community is fully convinced that we need to fix the problem urgently for our survival, good health, and wellbeing. The aim of this article is to promote the awareness about the United Nations (UN) historic 'Paris Agreement on Climate Change (PACC)' which entered into-force on 4 November 2016. The expected impact of PACC on the global average temperature rise by 2100 as well as its role in enabling accomplishment of global sustainable development goals (SDGs) for the people and planet is also highlighted.

Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

NASA Astrophysics Data System (ADS)

Hugenschmidt, Manfred

1986-10-01

The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

Paris Agreement on Climate Change: A Booster to Enable Sustainable Global Development and Beyond

PubMed Central

Bhore, Subhash Janardhan

2016-01-01

The global warming and its adverse effects on the atmosphere, the biosphere, the lithosphere, and the hydrosphere are obvious. Based on this fact, the international community is fully convinced that we need to fix the problem urgently for our survival, good health, and wellbeing. The aim of this article is to promote the awareness about the United Nations (UN) historic ‘Paris Agreement on Climate Change (PACC)’ which entered into-force on 4 November 2016. The expected impact of PACC on the global average temperature rise by 2100 as well as its role in enabling accomplishment of global sustainable development goals (SDGs) for the people and planet is also highlighted. PMID:27854248

76 FR 38013 - Safety Zone; Big Sioux River From the Military Road Bridge North Sioux City to the Confluence of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-29

... rising flood water. Operation in this zone is restricted unless specifically authorized by the Captain of... rising flood water. The impacts on routine navigation are expected to be minimal. Small Entities Under... vessels from destruction, loss or injury due to the hazards associated with rising flood water. If you are...

A Numeric Study of the Dependence of the Surface Temperature of Beta-Layered Regions on Absolute Thickness

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

Ebey, Peter S.; Asaki, Thomas J.; Hoffer, James K.

2000-01-15

Beta-layering of deuterium-tritium (D-T) ice in spherical shell geometries is numerically and analytically considered to investigate the relationship between temperature differences that arise because of inner-surface perturbations and the absolute shell thickness. The calculations use dimensions based on a proposed design of an inertial confinement fusion target for use at the National Ignition Facility. The temperature differences are calculated within D-T ice shells of varying total thicknesses, and the temperature differences calculated in three dimensions are compared both to the one-dimensional results and to the expected limits in three dimensions for long- and short-wavelength surface perturbations. The three-dimensional numeric resultsmore » agree well with both the long- and short-wavelength limits; the region of crossover from short- to long-wavelength behavior is mapped out. Temperature differences due to surface perturbations are proportional to D-T layer thickness in one-dimensional systems but not in three-dimensional spherical shells. In spherical shells, surface perturbations of long wavelength give rise to temperature perturbations that are approximately proportional to the total shell thickness, while for short-wavelength perturbations, the temperature differences are inversely related to total shell thickness. In contrast to the one-dimensional result, we find that in three dimensions there is not a general relationship between shell thickness and surface temperature differences.« less

Coral Energy Reserves and Calcification in a High-CO2 World at Two Temperatures

PubMed Central

Schoepf, Verena; Grottoli, Andréa G.; Warner, Mark E.; Cai, Wei-Jun; Melman, Todd F.; Hoadley, Kenneth D.; Pettay, D. Tye; Hu, Xinping; Li, Qian; Xu, Hui; Wang, Yongchen; Matsui, Yohei; Baumann, Justin H.

2013-01-01

Rising atmospheric CO2 concentrations threaten coral reefs globally by causing ocean acidification (OA) and warming. Yet, the combined effects of elevated pCO2 and temperature on coral physiology and resilience remain poorly understood. While coral calcification and energy reserves are important health indicators, no studies to date have measured energy reserve pools (i.e., lipid, protein, and carbohydrate) together with calcification under OA conditions under different temperature scenarios. Four coral species, Acropora millepora, Montipora monasteriata, Pocillopora damicornis, Turbinaria reniformis, were reared under a total of six conditions for 3.5 weeks, representing three pCO2 levels (382, 607, 741 µatm), and two temperature regimes (26.5, 29.0°C) within each pCO2 level. After one month under experimental conditions, only A. millepora decreased calcification (−53%) in response to seawater pCO2 expected by the end of this century, whereas the other three species maintained calcification rates even when both pCO2 and temperature were elevated. Coral energy reserves showed mixed responses to elevated pCO2 and temperature, and were either unaffected or displayed nonlinear responses with both the lowest and highest concentrations often observed at the mid-pCO2 level of 607 µatm. Biweekly feeding may have helped corals maintain calcification rates and energy reserves under these conditions. Temperature often modulated the response of many aspects of coral physiology to OA, and both mitigated and worsened pCO2 effects. This demonstrates for the first time that coral energy reserves are generally not metabolized to sustain calcification under OA, which has important implications for coral health and bleaching resilience in a high-CO2 world. Overall, these findings suggest that some corals could be more resistant to simultaneously warming and acidifying oceans than previously expected. PMID:24146747

Effects of temperature and pressure on thermodynamic properties of Cd0.50 Zn0.50 Se alloy

NASA Astrophysics Data System (ADS)

Aarifeen, Najm ul; Afaq, A.

2017-09-01

Thermodynamic properties of \\text{C}{{\\text{d}}0.50} \\text{Z}{{\\text{n}}0.50} Se alloy are studied using quasi harmonic model for pressure range 0-10 GPa and temperature range 0-1000 K. The structural optimization is obtained by self consistent field calculations and full-potential linear muffin-tin orbital method with GGA+U as an exchange correlation functional where U=2.3427 eV is the hubbard potential. The effects of temperature and pressure on the bulk modulus, Helmholtz free energy, internal energy, entropy, Debye temperature, Grüneisen parameter, thermal expansion coefficient and heat capacities of the material are observed and discussed. The bulk modulus, Helmholtz free energy and Debye temperature are found to decrease with increasing temperature while there is an increasing behavior when the pressure rises. Whereas internal energy has increasing trend with rises in temperature and it almost remains insensitive to pressure. The entropy of the system increases (decreases) with a rise of pressure (temperature).

Evaluation of Corrosion of the Dummy “EE” Plate 19 in YA Type ATR Fuel Element During Reactor PALM Cycles

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

Brower, Jeffrey Owen; Glazoff, Michael Vasily; Eiden, Thomas John

Advanced Test Reactor (ATR) Cycle 153B-1 was a 14-day, high-power, powered axial locator mechanism (PALM) operating cycle that completed on April 12, 2013. Cycle 153B-1 was a typical operating cycle for the ATR and did not result in any unusual plant transients. ATR was started up and shut down as scheduled. The PALM drive physically moves the selected experiments into and out of the core to simulate reactor startup and heat up, and shutdown and cooldown transients, while the reactor remains in steady state conditions. However, after the cycle was over, several thousand of the flow-assisted corrosion pits and “horseshoeing”more » defects were readily observable on the surface of the several YA-type fuel elements (these are “dummy” plates that contain no fuel). In order understand these corrosion phenomena a thermal-hydraulic model of coolant channel 20 on a YA-M fuel element was generated. The boundaries of the model were the aluminum EE plate of a YA-M fuel element and a beryllium reflector block with 13 horizontal saw cuts which represented regions of zero flow. The heat generated in fuel plates 1 through 18 was modeled to be passing through the aluminum EE plate. The coolant channel 20 width was set at 0.058 in. (58 mils). It was established that the horizontal saw cuts had a significant effect on the temperature of the coolant. The flow, which was expected to vary linearly with gradual heating of the coolant as it passed through the channel, was extremely turbulent. The temperature rise, which was expected to be a smooth “S” curve, was represented by a series temperature rise “humps,” which occurred at each horizontal saw cut in the beryllium reflector block. Each of the 13 saw cuts had a chamfered edge which resulted in the coolant flow being re-directed as a jet across the coolant channel into the surface of the EE plate, which explained the temperature rise and the observed sscalloping and possibly pitting degradation on the YA-M fuel elements. In the case of scalloping (horseshoeing) a surprising similarity of that defect to those appearing on aluminum plate rolled in over-lubrication conditions, were established. In turn, this made us think that the principal feature responsible for the appearance of these defects, was horizontal cuts in the Be neutron reflector created to arrest the propagation of large vertical crack(s) in Be in PALM cycles with higher overall fluence. This assumption was confirmed by the results of thermo-hydraulic simulations. The neutronics data for these modeling experiments were provided using rradiation simulations (MCNP, HELIOS). In the case of FAC and pitting corrosion the following corrective measures were proposed based upon the results of JMatPro modeling (TTT- and CCT-diagrams): change the practice of thermo-mechanical treatment of dummy plates in the future by adding blister anneal before program anneal, immediately after cold rolling of AA6061 ingot. This step will allow achieving complete recrystallization, eliminating of strengthening due to metastable precipitates, and reduce the possibility of forming sharp microstructural features upon the surface. Additionally it may prevent the formation of Fe-Al galvanic couples localized around such sharp particles. These recommendations were discussed with BWXT representatives and agreed upon by all parties. The new batch of plate manufactured using thus modified thermo-mechanical treatment is expected to be loaded into the ATR soon.« less

Temperature rise due to mechanical energy dissipation in undirectional thermoplastic composites(AS4/PEEK)

NASA Technical Reports Server (NTRS)

Georgious, I. T.; Sun, C. T.

1992-01-01

The history of temperature rise due to internal dissipation of mechanical energy in insulated off-axis uniaxial specimens of the unidirectional thermoplastic composite (AS4/PEEK) has been measured. The experiment reveals that the rate of temperature rise is a polynomial function of stress amplitude: It consists of a quadratic term and a sixth power term. This fact implies that the specific heat of the composite depends on the stretching its microstructure undergoes during deformation. The Einstein theory for specific heat is used to explain the dependence of the specific heat on the stretching of the microstructure.

Developed and developing world responsibilities for historical climate change and CO2 mitigation.

PubMed

Wei, Ting; Yang, Shili; Moore, John C; Shi, Peijun; Cui, Xuefeng; Duan, Qingyun; Xu, Bing; Dai, Yongjiu; Yuan, Wenping; Wei, Xin; Yang, Zhipeng; Wen, Tijian; Teng, Fei; Gao, Yun; Chou, Jieming; Yan, Xiaodong; Wei, Zhigang; Guo, Yan; Jiang, Yundi; Gao, Xuejie; Wang, Kaicun; Zheng, Xiaogu; Ren, Fumin; Lv, Shihua; Yu, Yongqiang; Liu, Bin; Luo, Yong; Li, Weijing; Ji, Duoying; Feng, Jinming; Wu, Qizhong; Cheng, Huaqiong; He, Jiankun; Fu, Congbin; Ye, Duzheng; Xu, Guanhua; Dong, Wenjie

2012-08-07

At the United Nations Framework Convention on Climate Change Conference in Cancun, in November 2010, the Heads of State reached an agreement on the aim of limiting the global temperature rise to 2 °C relative to preindustrial levels. They recognized that long-term future warming is primarily constrained by cumulative anthropogenic greenhouse gas emissions, that deep cuts in global emissions are required, and that action based on equity must be taken to meet this objective. However, negotiations on emission reduction among countries are increasingly fraught with difficulty, partly because of arguments about the responsibility for the ongoing temperature rise. Simulations with two earth-system models (NCAR/CESM and BNU-ESM) demonstrate that developed countries had contributed about 60-80%, developing countries about 20-40%, to the global temperature rise, upper ocean warming, and sea-ice reduction by 2005. Enacting pledges made at Cancun with continuation to 2100 leads to a reduction in global temperature rise relative to business as usual with a 1/3-2/3 (CESM 33-67%, BNU-ESM 35-65%) contribution from developed and developing countries, respectively. To prevent a temperature rise by 2 °C or more in 2100, it is necessary to fill the gap with more ambitious mitigation efforts.

Estimating the potential for methane clathrate instability in the 1%-CO2 IPCC AR-4 simulations

NASA Astrophysics Data System (ADS)

Lamarque, Jean-François

2008-10-01

The recent work of Reagan and Moridis (2007) has shown that even a limited warming of 1 K over 100 years can lead to clathrate destabilization, leading to a significant flux of methane into the ocean water, at least for shallow deposits. Here we study the potential for methane clathrate destabilization by identifying the 100-year temperature increase in the available IPCC (Intergovernmental Panel on Climate Change) AR-4 1%-CO2 increase per year (up to doubling over pre-industrial conditions, which occurs after 70 years) simulations. Depending on assumptions made on the possible locations (in this case, only depth) of methane clathrates and on temperature dependence, our calculation leads to an estimated model-mean release of methane at the bottom of the ocean of approximately 560-2140 Tg(CH4)/year; as no actual geographical distribution of methane clathrates is considered here, these flux estimates must be viewed as upper bound estimates. Using an observed 1% ratio to estimate the amount of methane reaching the atmosphere, our analysis leads to a relatively small methane flux of approximately 5-21 Tg(CH4)/year, with an estimated inter-model standard deviation of approximately 30%. The role of sea-level rise by 2100 will be to further stabilize methane clathrates, albeit to a small amount as the sea-level rise is expected to be less than a few meters.

Effects of Projected Future Climate Change on Groundwater Recharge and Storage for Two Coastal Aquifers in Guanacaste Province, Costa Rica

NASA Astrophysics Data System (ADS)

Kolb, C.

2017-12-01

Climate change is expected to pose a significant threat to water resources in the future. Guanacaste Province, located in northwestern Costa Rica, has a unique climate that is influenced by the Pacific Ocean and Caribbean Sea, as well as the Central Cordillera mountain range. Although the region experiences a marked rainy season between May and November, the hot, dry summers often stress water resources. Climate change projections suggest increased temperatures and reduced precipitation for the region, which will further stress water supplies. This study focuses on the effects of climate change on groundwater resources for two coastal aquifers, Potrero and Brasilito. The UZF model package coupled with the finite difference groundwater flow model MODFLOW were used to evaluate the effect of climate change on groundwater recharge and storage. A potential evapotranspiration model was used to estimate groundwater infiltration rates used in the MODFLOW model. Climate change projections for temperature, precipitation, and sea level rise were used to develop climate scenarios, which were compared to historical data. Preliminary results indicate that climate change could reduce future recharge, especially during the dry season. Additionally, the coastal aquifers are at increased risk of reduced storage and increased salinization due to the reductions in groundwater recharge and sea level rise. Climate change could also affect groundwater quality in the region, disrupting the ecosystem and impairing a primary source of drinking water.

State-space modeling of the relationship between air quality and mortality.

PubMed

Murray, C J; Nelson, C R

2000-07-01

A portion of a population is assumed to be at risk, with the mortality hazard varying with atmospheric conditions including total suspended particulates (TSP). This at-risk population is not observed and the hazard function is unknown; we wish to estimate these from mortality count and atmospheric variables. Consideration of population dynamics leads to a state-space representation, allowing the Kalman Filter (KF) to be used for estimation. A harvesting effect is thus implied; high mortality is followed by lower mortality until the population is replenished by new arrivals. The model is applied to daily data for Philadelphia, PA, 1973-1990. The estimated hazard function rises with the level of TSP and at extremes of temperature and also reflects a positive interaction between TSP and temperature. The estimated at-risk population averages about 480 and varies seasonally. We find that lags of TSP are statistically significant, but the presence of negative coefficients suggests their role may be partially statistical rather than biological. In the population dynamics framework, the natural metric for health damage from air pollution is its impact on life expectancy. The range of hazard rates over the sample period is 0.07 to 0.085, corresponding to life expectancies of 14.3 and 11.8 days, respectively.

Anode Sheath Contributions in Plasma Thrusters

DTIC Science & Technology

1994-03-01

and considerable throat erosion, is shown to be related to the electron temperature’s (T) rise above the gas temperature (To). An elementary one...surface damage and considerable throat erosion, is shown to be related to the electron temperature’s (T.) rise above the gas temperature (T.). An...Exhaust velocity is also limited hy material heating limitations of the combustion chamber and nozzle throat , and "frozen flow Losses" (unrecoverable energy

Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization

NASA Technical Reports Server (NTRS)

VanDresar, Neil T.

2014-01-01

This report presents the results of several thermodynamic vent system (TVS) tests with liquid oxygen plus a test with liquid nitrogen. In all tests, the liquid was heated above its normal boiling point to 111 K for oxygen and 100 K for nitrogen. The elevated temperature was representative of tank conditions for a candidate lunar lander ascent stage. An initial test series was conducted with saturated oxygen liquid and vapor at 0.6 MPa. The initial series was followed by tests where the test tank was pressurized with gaseous helium to 1.4 to 1.6 MPa. For these tests, the helium mole fraction in the ullage was quite high, about 0.57 to 0.62. TVS behavior is different when helium is present than when helium is absent. The tank pressure becomes the sum of the vapor pressure and the partial pressure of helium. Therefore, tank pressure depends not only on temperature, as is the case for a pure liquid-vapor system, but also on helium density (i.e., the mass of helium divided by the ullage volume). Thus, properly controlling TVS operation is more challenging with helium pressurization than without helium pressurization. When helium was present, the liquid temperature would rise with each successive TVS cycle if tank pressure was kept within a constant control band. Alternatively, if the liquid temperature was maintained within a constant TVS control band, the tank pressure would drop with each TVS cycle. The final test series, which was conducted with liquid nitrogen pressurized with helium, demonstrated simultaneous pressure and temperature control during TVS operation. The simultaneous control was achieved by systematic injection of additional helium during each TVS cycle. Adding helium maintained the helium partial pressure as the liquid volume decreased because of TVS operation. The TVS demonstrations with liquid oxygen pressurized with helium were conducted with three different fluid-mixer configurations-a submerged axial jet mixer, a pair of spray hoops in the tank ullage, and combined use of the axial jet and spray hoops. A submerged liquid pump and compact heat exchanger located inside the test tank were used with all the mixer configurations. The initial series without helium and the final series with liquid nitrogen both used the axial jet mixer. The axial jet configuration successfully demonstrated the ability to control tank pressure; but in the normal-gravity environment, the temperature in the upper tank region (ullage and unwetted wall) was not controlled. The spray hoops and axial jet combination also successfully demonstrated pressure control as well as temperature control of the entire tank and contents. The spray-hoops-only configuration was not expected to be a reliable means of tank mixing because there was no direct means to produce liquid circulation. However, surprisingly good results also were obtained with the sprayhoops- only configuration (i.e., performance metrics such as cycle-averaged vent flowrate were similar to those obtained with the other configurations). A simple thermodynamic model was developed that correctly predicted the TVS behavior (temperature rise or pressure drop per TVS cycle) when helium was present in the ullage. The model predictions were correlated over a range of input parameters. The correlations show that temperature rise or pressure drop per cycle was proportional to both helium mole fraction and tank heat input. The response also depended on the tank fill fraction: the temperature rise or pressure drop (per TVS cycle) increased as the ullage volume decreased.

Monarch butterfly population decline in North America: identifying the threatening processes

USGS Publications Warehouse

Thogmartin, Wayne E.; Wiederholt, Ruscena; Oberhauser, Karen; Drum, Ryan G.; Diffendorfer, Jay E.; Altizer, Sonia; Taylor, Orley R.; Pleasants, John M.; Semmens, Darius J.; Semmens, Brice X.; Erickson, Richard A.; Libby, Kaitlin; Lopez-Hoffman, Laura

2017-01-01

The monarch butterfly (Danaus plexippus) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.

Coral reefs under rapid climate change and ocean acidification.

PubMed

Hoegh-Guldberg, O; Mumby, P J; Hooten, A J; Steneck, R S; Greenfield, P; Gomez, E; Harvell, C D; Sale, P F; Edwards, A J; Caldeira, K; Knowlton, N; Eakin, C M; Iglesias-Prieto, R; Muthiga, N; Bradbury, R H; Dubi, A; Hatziolos, M E

2007-12-14

Atmospheric carbon dioxide concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2 degrees C by 2050 to 2100, values that significantly exceed those of at least the past 420,000 years during which most extant marine organisms evolved. Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse reef communities and carbonate reef structures that fail to be maintained. Climate change also exacerbates local stresses from declining water quality and overexploitation of key species, driving reefs increasingly toward the tipping point for functional collapse. This review presents future scenarios for coral reefs that predict increasingly serious consequences for reef-associated fisheries, tourism, coastal protection, and people. As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.

Engaging a moving target: Adapting to rates of climate change

NASA Astrophysics Data System (ADS)

Shayegh, S.; Caldeira, K.; Moreno-Cruz, J.

2015-12-01

Climate change is affecting the planet and its human and natural systems at an increasing rate. As temperatures continue to rise, the international community has increasingly been considering adaptation measures to prepare for future climate change. However, most discussion around adaptation strategies has focused on preparedness for some expected amount of climate change impacts, e.g. 2 meters sea level rise. In this study, we discuss adaptation to rates of change as an alternative conceptual framework for thinking about adaptation. Adaptation is not only about adapting to amounts of change, but the rate at which these changes occur is also critically important. We ground our discussion with an example of optimal coastal investment in the face of ongoing sea level rise. Sea level rise threatens coastal assets. Finite resources could be devoted to building infrastructure further inland or to building coastal defense systems. A possible policy response could be to create a "no-build" coastal buffer zone that anticipates a future higher sea level. We present a quantitative model that illustrates the interplay among various important factors (rate of sea level rise, discount rate, capital depreciation rate, attractiveness of coastal land, etc). For some cases, strategies that combine periodic defensive investments (e.g. dikes) with planned retreat can maximize welfare when adapting to rates of climate change. In other cases, planned retreat may be optimal. It is important to prepare for ongoing increasing amounts of climate change. Preparing for a fixed amount of climate change can lead to a suboptimal solution. Climate is likely to continue changing throughout this century and beyond. To reduce adverse climate impacts, ecosystems and human systems will need to continuously adapt to a moving target.

What has contributed to the change in life expectancy in Italy between 1980 and 1992?

PubMed

Ngongo, K N; Nante, N; Chenet, L; McKee, M

1999-07-01

Life expectancy at birth in southern Europe is known to be greater than expected in comparison with levels of economic development. This has been attributed to the 'Mediterranean diet'. There are, however, concerns that this comparative advantage is being lost. This paper examines the factors underlying changing life expectancy in Italy since 1980. The subjects of this analysis are obtained from data on all deaths in Italy between 1980 and 1992. Change in age specific death rates is calculated from selected causes and, using the method developed by Pollard, the contribution of deaths from different causes and at different ages to changing life expectancy at birth is estimated. Between 1980 and 1992, life expectancy at birth increased by 2.70 years for men and 2.75 years for women. Death rates have fallen among children and those over 40. In contrast, death rates have increased among men aged between 20 and 39 and have increased very slightly among women aged 25-29. Falling death rates from ischaemic heart disease are continuing to contribute to increasing life expectancy. Death rates from lung and breast cancer are rising among women but are compensated for by falling death rates from other cancers. Among men, falling death rates from cancer at younger ages are being offset by increases at older ages. The rising death rate among younger men is almost entirely due to AIDS, with accidents also making a small contribution. Life expectancy in Italy has improved throughout the 1980s, largely driven by falling death rates from cardiovascular diseases. Here are, however, some worrying trends, most notably the rising death rate among young men, due almost entirely to AIDS. The changing pattern of mortality has some similarities with Spain, another Mediterranean country, but there are also important differences.

Effect of storage conditions on the calorific value of municipal solid waste.

PubMed

Nzioka, Antony Mutua; Hwang, Hyeon-Uk; Kim, Myung-Gyun; Yan, Cao Zheng; Lee, Chang-Soo; Kim, Young-Ju

2017-08-01

Storage conditions are considered to be an important factor as far as waste material characteristics are concerned. This experimental investigation was conducted using municipal solid waste (MSW) with a high moisture content and varying composition of organic waste. The objective of this study was to understand the effect of storage conditions and temperature on the moisture content and calorific value of the waste. Samples were subjected to two different storage conditions and investigated at specified temperatures. The composition of sample materials investigated was varied for each storage condition and temperature respectively. Gross calorific value was determined experimentally while net calorific value was calculated using empirical formulas proposed by other researchers. Results showed minimal changes in moisture content as well as in gross and net calorific values when the samples were subjected to sealed storage conditions. Moisture content reduced due to the ventilation process and the rate of moisture removal increased with a rise in storage temperature. As expected, rate of moisture removal had a positive effect on gross and net calorific values. Net calorific values also increased at varying rates with a simultaneous decrease in moisture content. Experimental investigation showed the effectiveness of ventilation in improving the combustion characteristics of the waste.

Relationships between ten-year trends of tropospheric ozone and temperature over Taiwan.

PubMed

Hsu, Kuang-Jung

2007-03-01

The analyses of ten-year ozonesonde observations from 1993 till 2002, over Taipei, Taiwan show influences of climate change. Despite huge increases in its precursor emissions in this region, there were little variations in tropospheric ozone. Results indicate a warmer troposphere, a statistically insignificant rising tropopause, 79+/-206 m per decade, and decreasing tropopause temperature at -1.0+/-0.89 K per decade. The derived mean tropospheric ozone is 40.58+/-10.99 DU, and has a statistically insignificant small trend of -0.78+/-1.7 DU per decade. The derived ten-year vertical trends of temperature and ozone are inversely correlated with each other from the middle troposphere up to the lower stratosphere. The averaged monthly vertical temperature trends show a generally warmer middle troposphere. The tropospheric ozone monthly trend has small increases only in the lower troposphere during winter and spring. Strong decreases occur in summer, from the surface up into the stratosphere. For ozone variation, results suggest that influences of climate forcing are stronger than those from precursor increases. More frequent and/or intense convection in summer and other climate-induced effects may contribute to the less than expected ozone observed in the troposphere.

Model development and experimental validation for analyzing initial transients of irradiation of tissues during thermal therapy using short pulse lasers.

PubMed

Ganguly, Mohit; Miller, Stephanie; Mitra, Kunal

2015-11-01

Short pulse lasers with pulse durations in the range of nanoseconds and shorter are effective in the targeted delivery of heat energy for precise tissue heating and ablation. This photothermal therapy is useful where the removal of cancerous tissue sections is required. The objective of this paper is to use finite element modeling to demonstrate the differences in the thermal response of skin tissue to short-pulse and continuous wave laser irradiation in the initial stages of the irradiation. Models have been developed to validate the temperature distribution and heat affected zone during laser irradiation of excised rat skin samples and live anesthetized mouse tissue. Excised rat skin samples and live anesthetized mice were subjected to Nd:YAG pulsed laser (1,064 nm, 500 ns) irradiation of varying powers. A thermal camera was used to measure the rise in surface temperature as a result of the laser irradiation. Histological analyses of the heat affected zone created in the tissue samples due to the temperature rise were performed. The thermal interaction of the laser with the tissue was quantified by measuring the thermal dose delivered by the laser. Finite element geometries of three-dimensional tissue sections for continuum and vascular models were developed using COMSOL Multiphysics. Blood flow was incorporated into the vascular model to mimic the presence of discrete blood vessels and contrasted with the continuum model without blood perfusion. The temperature rises predicted by the continuum and the vascular models agreed with the temperature rises observed at the surface of the excised rat tissue samples and live anesthetized mice due to laser irradiation respectively. The vascular model developed was able to predict the cooling produced by the blood vessels in the region where the vessels were present. The temperature rise in the continuum model due to pulsed laser irradiation was higher than that due to continuous wave (CW) laser irradiation in the initial stages of the irradiation. The temperature rise due to pulsed and CW laser irradiation converged as the time of irradiation increased. A similar trend was observed when comparing the thermal dose for pulsed and CW laser irradiation in the vascular model. Finite element models (continuum and vascular) were developed that can be used to predict temperature rise and quantify the thermal dose resulting from laser irradiation of excised rat skin samples and live anesthetized mouse tissue. The vascular model incorporating blood perfusion effects predicted temperature rise better in the live animal tissue. The models developed demonstrated that pulsed lasers caused greater temperature rise and delivered a greater thermal dose than CW lasers of equal average power, especially during the initial transients of irradiation. This analysis will be beneficial for thermal therapy applications where maximum delivery of thermal dose over a short period of time is important. © 2015 Wiley Periodicals, Inc.

An experimental investigation of temperature rise during compaction of pharmaceutical powders.

PubMed

Krok, Alexander; Mirtic, Andreja; Reynolds, Gavin K; Schiano, Serena; Roberts, Ron; Wu, Chuan-Yu

2016-11-20

During pharmaceutical powder compaction, temperature rise in the compressed powder can affect physiochemical properties of the powder, such as thermal degradation and change in crystallinity. Thus, it is of practical importance to understand the effect of process conditions and material properties on the thermal response of pharmaceutical formulations during compaction. The aim of this study was to examine the temperature rise of pharmaceutical powders during tableting, in particular, to explore how the temperature rise depends on material properties, compression speed and tablet shape. Three grades of microcrystalline cellulose (MCC) were considered: MCC Avicel pH 101, MCC Avicel pH 102 and MCC DG. These powders were compressed using a compaction simulator at various compaction speeds (10-500mm/s). Flat faced, shallow convex and normal convex tablets were produced and temperature distributions on the surface of theses tablets upon ejection were examined using an infrared thermoviewer. It was found that an increase in the compaction speed led to an increase in the average surface temperature. A higher surface temperature was induced when the powder was compressed into a tablet with larger surface curvature. This was primarily due to the increasing degree of powder deformation (i.e. the volume reduction) and the effect of interparticule/wall friction. Copyright © 2016 Elsevier B.V. All rights reserved.

A comparison of thermocouple and infrared thermographic analysis of temperature rise on the root surface during the continuous wave of condensation technique.

PubMed

Mc Cullagh, J J; Setchell, D J; Gulabivala, K; Hussey, D L; Biagioni, P; Lamey, P J; Bailey, G

2000-07-01

This study was designed to use two methods of temperature measurement to analyse and quantify the in vitro root surface temperature changes during the initial stage of the continuous wave technique of obturation of 17 single-rooted premolar teeth with standard canal preparations. A model was designed to allow simultaneous temperature measurement with both thermocouples and an infrared thermal imaging system. Two thermocouples were placed on the root surface, one coronally and the other near the root apex. A series of thermal images were recorded by an infrared thermal imaging camera during the downpack procedure. The mean temperature rises on the root surface, as measured by the two thermocouples, averaged 13.9 degrees C over the period of study, whilst the infrared thermal imaging system measured an average rise of 28.4 degrees C at the same sites. Temperatures at the more apical point were higher than those measured coronally. After the first wave of condensation, the second activation of the plugger in the canal prior to its removal always resulted in a secondary rise in temperature. The thermal imaging system detected areas of greater temperature change distant from the two selected thermocouple sites. The continuous wave technique of obturation may result in high temperatures on the external root surface. Infrared thermography is a useful device for mapping patterns of temperature change over a large area.

Thermally modulated biomolecule transport through nanoconfined channels

NASA Astrophysics Data System (ADS)

Liu, Lei; Zhu, Lizhong

2015-04-01

In this work, a nanofluidic device containing both a feed cell and a permeation cell linked by nanopore arrays has been fabricated, which is employed to investigate thermally controlled biomolecular transporting properties through confined nanochannels. The ionic currents modulated by the translocations of goat antibody to human immunoglobulin G (IgG) or bovine serum albumin (BSA) are recorded and analyzed. The results suggest that the modulation effect decreases with the electrolyte concentration increasing, while the effects generated by IgG translocation are more significant than that generated by BSA translocation. More importantly, there is a maximum decreasing value in each modulated current curve with biomolecule concentration increasing for thermally induced intermolecular collision. Furthermore, the turning point for the maximum shifts to lower biomolecule concentrations with the system temperature rising (from 4°C to 45°C), and it is mainly determined by the temperature in the feed cell if the temperature difference exists in the two separated cells. These findings are expected to be valuable for the future design of novel sensing device based on nanopore and/or nanopore arrays.

Vibrational Properties of Zr(Hf)B2-SiC UHTC Composites by Micro-Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Donohue, M.; Carpenter, C.; Orlovskaya, N.

Development and characterization of novel materials that are lightweight, possess high mechanical properties, can withstand high temperatures, and provide superior thermal properties are crucial to meet the future demands of Air Force, Army, Navy, Missile Defense Agency (MDA), and other military and space agencies. Materials for such applications (hypersonic air-breathing vehicles, including Single-To-Orbit vehicles and Two-Stage-To-Orbit aerospace planes, fully reusable space transport vehicles, hypersonic cruise missiles) experience severe aero-thermal loads with nose-cone and nozzle temperatures in excess of 2,000°F and 4,000°F, respectively. High G acceleration is also a problem. Even the most advanced materials, such as Ti, Inconel X, carbon-carbon, and silicon carbide based composites cannot withstand the excessive heat generated, especially during re-entry, and they cannot meet the guidelines for future high performance aircrafts, kinetic energy interceptors and reusable space planes. Thus, the demand for low-cost, light weight high temperature materials for thermal protection systems (TPS) is expected to be on the significant rise in the near future.

Direct benefits and indirect costs of warm temperatures for high-elevation populations of a solitary bee.

PubMed

Forrest, Jessica R K; Chisholm, Sarah P M

2017-02-01

Warm temperatures are required for insect flight. Consequently, warming could benefit many high-latitude and high-altitude insects by increasing opportunities for foraging or oviposition. However, warming can also alter species interactions, including interactions with natural enemies, making the net effect of rising temperatures on population growth rate difficult to predict. We investigated the temperature-dependence of nesting activity and lifetime reproductive output over 3 yr in subalpine populations of a pollen-specialist bee, Osmia iridis. Rates of nest provisioning increased with ambient temperatures and with availability of floral resources, as expected. However, warmer conditions did not increase lifetime reproductive output. Lifetime offspring production was best explained by rates of brood parasitism (by the wasp Sapyga), which increased with temperature. Direct observations of bee and parasite activity suggest that although activity of both species is favored by warmer temperatures, bees can be active at lower ambient temperatures, while wasps are active only at higher temperatures. Thus, direct benefits to the bees of warmer temperatures were nullified by indirect costs associated with increased parasite activity. To date, most studies of climate-change effects on pollinators have focused on changing interactions between pollinators and their floral host-plants (i.e., bottom-up processes). Our results suggest that natural enemies (i.e., top-down forces) can play a key role in pollinator population regulation and should not be overlooked in forecasts of pollinator responses to climate change. © 2016 by the Ecological Society of America.

Elastic anomalies and acoustic dissipation associated with spin state transitions in LnCoO3 (Ln=La, Nd, Gd) and Co3O4: analogue behaviour for spin state transitions in minerals

NASA Astrophysics Data System (ADS)

Zhang, Z.; Carpenter, M. A.; Koppensteiner, J.; Schranz, W.

2010-12-01

Iron ions in lower mantle minerals magnesiowüstitue (Mg,Fe)O, perovskite (Mg,Fe)(Si,Al)O3 and post-perovskite phases undergo electronic spin state transitions from high spin (HS) to low spin (LS) or intermediate spin (IS) at high pressures and high temperatures. These spin state transitions give rise to changes in bulk and shear moduli which have significant implications for the physical and chemical properties of the lower mantle. However, the possibility of increased attenuation does not appear to have been considered yet. Co3+ is isoelectronic with Fe2+ and shows analogous HS/LS behaviour at ambient pressure in a temperature range which is easily accessible for in-situ investigations. We have studied spin state transitions in cobalt perovskites LaCoO3, NdCoO3, GdCoO3 and in Co3O4 using resonant ultrasound spectroscopy (RUS) at high frequencies 0.1-1.5 MHz, and dynamic mechanical analysis (DMA) at low frequencies 0.1-50 Hz, in the temperature range 10-1200 K. The specific objectives were to characterize anomalies in the shear moduli and in acoustic attenuation accompanying changes in the spin state of Co3+. Anomalies in shear moduli have been observed at ~110 K and ~590 K for LaCoO3, ~325 K and ~695 K for NdCoO3, ~720 K for GdCoO3, and ~30 K for Co3O4. For LaCoO3, a spin order parameter qspin is expected to couple with volume strain ea as λeaqspin and with shear strain es as λes2qspin. As a consequence of linear/quadratic coupling with es, the shear modulus is expected to vary linearly with qspin. This appears to be approximately the case for LaCoO3. Changes in spin state do not appear to give rise to acoustic attenuation at either DMA frequencies (~1 Hz) or RUS frequencies (~1 MHz), consistent with the expectation that spin/lattice relaxation is rapid in comparison with the time scale of applied stress in each case. On the other hand, for LaCoO3 there is a peak in dissipation near 590 K at low frequencies, which is attributed to freezing of ferroelastic twin walls. At high frequencies, acoustic attenuation increases steeply below ~110 K, and this is attributed to movement of magnetic polarons under stress. Data for thermally activated relaxation processes in LaCoO3 based on different measurements from the literature and our own elasticity data have been combined to give a preliminary anelasticity map. At seismic frequencies, loss mechanisms are likely to be only due to twin wall and magnetic polaron mobility. NdCoO3 and GdCoO3 both have the Pnma structure at room temperature. They also show significant non-linear behaviour in shear modulus as a function of temperature but neither show evidence of significant attenuation which might be attributed to microstructure, spin/lattice coupling or polarons. On the other hand, Co3O4 shows evidence of increasing attenuation above ~800 K and below ~30 K at high frequencies. The origin of the latter is clearly associated with magnetic ordering in this system but the origin of the former is not yet understood, particularly as Co3O4 crystals are not expected to contain any transformation microstructure.

Windage Heating in a Shrouded Rotor-Stator System.

PubMed

Tao, Zhi; Zhang, Da; Luo, Xiang; Xu, Guoqiang; Han, Jianqiao

2014-06-01

This paper has experimentally and numerically studied the windage heating in a shrouded rotor-stator disk system with superimposed flow. Temperature rise in the radius direction on the rotating disk is linked to the viscous heating process when cooling air flows through the rotating component. A test rig has been developed to investigate the effect of flow parameters and the gap ratio on the windage heating, respectively. Experimental results were obtained from a 0.45 m diameter disk rotating at up to 12,000 rpm with gap ratio varying from 0.02 to 0.18 and a stator of the same diameter. Infrared temperature measurement technology has been proposed to measure the temperature rise on the rotor surface directly. The PIV technique was adapted to allow for tangential velocity measurements. The tangential velocity data along the radial direction in the cavity was compared with the results obtained by CFD simulation. The comparison between the free disk temperature rise data and an associated theoretical analysis for the windage heating indicates that the adiabatic disk temperature can be measured by infrared method accurately. For the small value of turbulence parameter, the gap ratio has limited influence on the temperature rise distribution along the radius. As turbulence parameter increases, the temperature rise difference is independent of the gap ratio, leaving that as a function of rotational Reynolds number and throughflow Reynolds number only. The PIV results show that the swirl ratio of the rotating core between the rotor and the stator has a key influence on the windage heating.

Role of superconducting electronics in advancing science and technology (invited) (abstract)

NASA Astrophysics Data System (ADS)

Faris, S. M.

1988-08-01

The promises of the ultrahigh-performance properties of superconductivity and Josephson junction technologies have been known for quite some time. This presentation describes the first superconducting electronics and measurement system and its important role as a major tool to advance microwave and millimeter wave technologies. This breakthrough tool is a sampling oscilloscope with 5-ps rise time, 50-μV sensitivity, and a time domain reflectometer with 8-ps rise time. In order to achieve these performance goals, several technological hurdles had to be overcome including perfecting a manufacturing process for building Josephson junction IC chips, developing an innovative cooling technique, developing interfaces and interconnections with bandwidths in excess of 70 GHz, and developing the room-temperature hardware and software necessary to make the instruments convenient, easy to use, easy to learn, in addition to making available functions and features users have come to expect from sophisticated digital test instrumentation. These technological developments are stepping stones leading to the realization of more sophisticated and complex electronic systems satisfying the needs of scientists, technologists, and engineers. The unprecedented speed and sensitivity make it possible to attack new frontiers.

Climatic sensitivity, water-use efficiency, and growth decline in boreal jack pine (Pinus banksiana) forests in Northern Ontario

NASA Astrophysics Data System (ADS)

Dietrich, Rachel; Bell, F. Wayne; Silva, Lucas C. R.; Cecile, Alice; Horwath, William R.; Anand, Madhur

2016-10-01

Rises in atmospheric carbon dioxide (atmCO2) levels are known to stimulate photosynthesis and increase intrinsic water-use efficiency (iWUE) in trees. Stand-level increases in iWUE depend on the physiological response of dominant species to increases in atmCO2, while tree-level response to increasing atmCO2 depends on the balance between the direct effects of atmCO2 on photosynthetic rate and the indirect effects of atmCO2 on drought conditions. The aim of this study was to characterize the response of boreal jack pine (Pinus banksiana) stands in Northern Ontario to changes in atmCO2 and associated climatic change over the past 100 years. The impact of changes in growing season length, temperature, and precipitation, as well as atmCO2 on tree growth, was determined using stable carbon isotopes and dendrochronological analysis. Jack pine stands in this study were shown to be in progressive decline. As expected, iWUE was found to increase in association with rising atmCO2. However, increases in iWUE were not directly coupled with atmCO2, suggesting that the degree of iWUE improvement is limited by alternative factors. Water-use efficiency was negatively associated with tree growth, suggesting that warming- and drought-induced stomatal closure has likely led to deviations from expected atmCO2-enhanced growth. This finding corroborates that boreal forest stands are likely to face continued stress under future climatic warming.

Communicating the deadly consequences of global warming for human heat stress

NASA Astrophysics Data System (ADS)

Matthews, Tom K. R.; Wilby, Robert L.; Murphy, Conor

2017-04-01

In December of 2015, the international community pledged to limit global warming to below 2 °C above preindustrial (PI) to prevent dangerous climate change. However, to what extent, and for whom, is danger avoided if this ambitious target is realized? We address these questions by scrutinizing heat stress, because the frequency of extremely hot weather is expected to continue to rise in the approach to the 2 °C limit. We use analogs and the extreme South Asian heat of 2015 as a focusing event to help interpret the increasing frequency of deadly heat under specified amounts of global warming. Using a large ensemble of climate models, our results confirm that global mean air temperature is nonlinearly related to heat stress, meaning that the same future warming as realized to date could trigger larger increases in societal impacts than historically experienced. This nonlinearity is higher for heat stress metrics that integrate the effect of rising humidity. We show that, even in a climate held to 2 °C above PI, Karachi (Pakistan) and Kolkata (India) could expect conditions equivalent to their deadly 2015 heatwaves every year. With only 1.5 °C of global warming, twice as many megacities (such as Lagos, Nigeria, and Shanghai, China) could become heat stressed, exposing more than 350 million more people to deadly heat by 2050 under a midrange population growth scenario. The results underscore that, even if the Paris targets are realized, there could still be a significant adaptation imperative for vulnerable urban populations.

Communicating the deadly consequences of global warming for human heat stress.

PubMed

Matthews, Tom K R; Wilby, Robert L; Murphy, Conor

2017-04-11

In December of 2015, the international community pledged to limit global warming to below 2 °C above preindustrial (PI) to prevent dangerous climate change. However, to what extent, and for whom, is danger avoided if this ambitious target is realized? We address these questions by scrutinizing heat stress, because the frequency of extremely hot weather is expected to continue to rise in the approach to the 2 °C limit. We use analogs and the extreme South Asian heat of 2015 as a focusing event to help interpret the increasing frequency of deadly heat under specified amounts of global warming. Using a large ensemble of climate models, our results confirm that global mean air temperature is nonlinearly related to heat stress, meaning that the same future warming as realized to date could trigger larger increases in societal impacts than historically experienced. This nonlinearity is higher for heat stress metrics that integrate the effect of rising humidity. We show that, even in a climate held to 2 °C above PI, Karachi (Pakistan) and Kolkata (India) could expect conditions equivalent to their deadly 2015 heatwaves every year. With only 1.5 °C of global warming, twice as many megacities (such as Lagos, Nigeria, and Shanghai, China) could become heat stressed, exposing more than 350 million more people to deadly heat by 2050 under a midrange population growth scenario. The results underscore that, even if the Paris targets are realized, there could still be a significant adaptation imperative for vulnerable urban populations.

Effects of implant drilling parameters for pilot and twist drills on temperature rise in bone analog and alveolar bones.

PubMed

Chen, Yung-Chuan; Hsiao, Chih-Kun; Ciou, Ji-Sih; Tsai, Yi-Jung; Tu, Yuan-Kun

2016-11-01

This study concerns the effects of different drilling parameters of pilot drills and twist drills on the temperature rise of alveolar bones during dental implant procedures. The drilling parameters studied here include the feed rate and rotation speed of the drill. The bone temperature distribution was analyzed through experiments and numerical simulations of the drilling process. In this study, a three dimensional (3D) elasto-plastic dynamic finite element model (DFEM) was proposed to investigate the effects of drilling parameters on the bone temperature rise. In addition, the FE model is validated with drilling experiments on artificial human bones and porcine alveolar bones. The results indicate that 3D DFEM can effectively simulate the bone temperature rise during the drilling process. During the drilling process with pilot drills or twist drills, the maximum bone temperature occurred in the region of the cancellous bones close to the cortical bones. The feed rate was one of the important factors affecting the time when the maximum bone temperature occurred. Our results also demonstrate that the elevation of bone temperature was reduced as the feed rate increased and the drill speed decreased, which also effectively reduced the risk region of osteonecrosis. These findings can serve as a reference for dentists in choosing drilling parameters for dental implant surgeries. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Improved rolling element bearings provide low torque and small temperature rise in ultrahigh vacuum environment

NASA Technical Reports Server (NTRS)

Glenn, D. C.

1966-01-01

Rolling element bearing with stainless steel races and rolling elements and a porous bronze cage successfully operates in ultrahigh vacuum environments at a low torque and with small temperature rise. All components are burnished in molybdenum disulfide.

Ambient high temperature and mortality in Jinan, China: A study of heat thresholds and vulnerable populations.

PubMed

Li, Jing; Xu, Xin; Yang, Jun; Liu, Zhidong; Xu, Lei; Gao, Jinghong; Liu, Xiaobo; Wu, Haixia; Wang, Jun; Yu, Jieqiong; Jiang, Baofa; Liu, Qiyong

2017-07-01

Understanding the health consequences of continuously rising temperatures-as is projected for China-is important in terms of developing heat-health adaptation and intervention programs. This study aimed to examine the association between mortality and daily maximum (T max ), mean (T mean ), and minimum (T min ) temperatures in warmer months; to explore threshold temperatures; and to identify optimal heat indicators and vulnerable populations. Daily data on temperature and mortality were obtained for the period 2007-2013. Heat thresholds for condition-specific mortality were estimated using an observed/expected analysis. We used a generalised additive model with a quasi-Poisson distribution to examine the association between mortality and T max /T min /T mean values higher than the threshold values, after adjustment for covariates. T max /T mean /T min thresholds were 32/28/24°C for non-accidental deaths; 32/28/24°C for cardiovascular deaths; 35/31/26°C for respiratory deaths; and 34/31/28°C for diabetes-related deaths. For each 1°C increase in T max /T mean /T min above the threshold, the mortality risk of non-accidental-, cardiovascular-, respiratory, and diabetes-related death increased by 2.8/5.3/4.8%, 4.1/7.2/6.6%, 6.6/25.3/14.7%, and 13.3/30.5/47.6%, respectively. Thresholds for mortality differed according to health condition when stratified by sex, age, and education level. For non-accidental deaths, effects were significant in individuals aged ≥65 years (relative risk=1.038, 95% confidence interval: 1.026-1.050), but not for those ≤64 years. For most outcomes, women and people ≥65 years were more vulnerable. High temperature significantly increases the risk of mortality in the population of Jinan, China. Climate change with rising temperatures may bring about the situation worse. Public health programs should be improved and implemented to prevent and reduce health risks during hot days, especially for the identified vulnerable groups. Copyright © 2017. Published by Elsevier Inc.

[Effects of ultrasonic pretreatment on drying characteristics of sewage sludge].

PubMed

Li, Run-Dong; Yang, Yu-Ting; Li, Yan-Long; Niu, Hui-Chang; Wei, Li-Hong; Sun, Yang; Ke, Xin

2009-11-01

The high water content of sewage sludge has engendered many inconveniences to its treatment and disposal. While ultrasonic takes on unique advantages on the sludge drying because of its high ultrasonic power, mighty penetrating capability and the ability of causing cavitations. Thus this research studies the characteristics influences of ultrasonic bring to the sludge drying and effects of the exposure time, ultrasonic generator power, temperatures of ultrasonic and drying temperature on the drying characteristics of dewatered sludge. Results indicate that ultrasonic pretreatment could speed up evaporation of the free water in sludge surface and help to end the drying stage with constant speed. In addition, ultrasonic treatment can effectively improve the sludge drying efficiency which could be more evident with the rise of the ultrasonic power (100-250 W), ultrasonic temperature and drying temperature. If dried under low temperature such as 105 degrees C, sludge will have premium drying characteristics when radiated under ultrasound for a shorter time such as 3 min. In the end, the ultrasonic treatment is expected to be an effective way to the low-cost sludge drying and also be an important reference to the optimization of the sludge drying process because of its effects on the increase of sludge drying efficiency.

Upper temperature limits of tropical marine ectotherms: global warming implications.

PubMed

Nguyen, Khanh Dung T; Morley, Simon A; Lai, Chien-Houng; Clark, Melody S; Tan, Koh Siang; Bates, Amanda E; Peck, Lloyd S

2011-01-01

Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour(-1), the upper lethal temperature range of intertidal ectotherms was 41-52°C, but this range was narrower and reduced to 37-41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2-3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming.

Rising Mercury, Rising Hostility: How Heat Affects Survey Response

ERIC Educational Resources Information Center

Cohen, Alexander H.; Krueger, James S.

2016-01-01

Recent social scientific research has examined connections between public opinion and weather conditions. This article contributes to this literature by analyzing the relationship between high temperature and survey response. Because hot temperatures are associated with aggression, irritation, and negativity, such conditions should lead to the…

Calculation of Temperature Rise in Calorimetry.

ERIC Educational Resources Information Center

Canagaratna, Sebastian G.; Witt, Jerry

1988-01-01

Gives a simple but fuller account of the basis for accurately calculating temperature rise in calorimetry. Points out some misconceptions regarding these calculations. Describes two basic methods, the extrapolation to zero time and the equal area method. Discusses the theoretical basis of each and their underlying assumptions. (CW)

Statistical modeling of daily and subdaily stream temperatures: Application to the Methow River Basin, Washington

NASA Astrophysics Data System (ADS)

Caldwell, R. J.; Gangopadhyay, S.; Bountry, J.; Lai, Y.; Elsner, M. M.

2013-07-01

Management of water temperatures in the Columbia River Basin (Washington) is critical because water projects have substantially altered the habitat of Endangered Species Act listed species, such as salmon, throughout the basin. This is most important in tributaries to the Columbia, such as the Methow River, where the spawning and rearing life stages of these cold water fishes occurs. Climate change projections generally predict increasing air temperatures across the western United States, with less confidence regarding shifts in precipitation. As air temperatures rise, we anticipate a corresponding increase in water temperatures, which may alter the timing and availability of habitat for fish reproduction and growth. To assess the impact of future climate change in the Methow River, we couple historical climate and future climate projections with a statistical modeling framework to predict daily mean stream temperatures. A K-nearest neighbor algorithm is also employed to: (i) adjust the climate projections for biases compared to the observed record and (ii) provide a reference for performing spatiotemporal disaggregation in future hydraulic modeling of stream habitat. The statistical models indicate the primary drivers of stream temperature are maximum and minimum air temperature and stream flow and show reasonable skill in predictability. When compared to the historical reference time period of 1916-2006, we conclude that increases in stream temperature are expected to occur at each subsequent time horizon representative of the year 2020, 2040, and 2080, with an increase of 0.8 ± 1.9°C by the year 2080.

Direct Control of SPEECHLESS by PIF4 in the High-Temperature Response of Stomatal Development.

PubMed

Lau, On Sun; Song, Zhuojun; Zhou, Zimin; Davies, Kelli A; Chang, Jessica; Yang, Xin; Wang, Shenqi; Lucyshyn, Doris; Tay, Irene Hui Zhuang; Wigge, Philip A; Bergmann, Dominique C

2018-04-23

Environmental factors shape the phenotypes of multicellular organisms. The production of stomata-the epidermal pores required for gas exchange in plants-is highly plastic and provides a powerful platform to address environmental influence on cell differentiation [1-3]. Rising temperatures are already impacting plant growth, a trend expected to worsen in the near future [4]. High temperature inhibits stomatal production, but the underlying mechanism is not known [5]. Here, we show that elevated temperature suppresses the expression of SPEECHLESS (SPCH), the basic-helix-loop-helix (bHLH) transcription factor that serves as the master regulator of stomatal lineage initiation [6, 7]. Our genetic and expression analyses indicate that the suppression of SPCH and stomatal production is mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4), a core component of high-temperature signaling [8]. Importantly, we demonstrate that, upon exposure to high temperature, PIF4 accumulates in the stomatal precursors and binds to the promoter of SPCH. In addition, we find SPCH feeds back negatively to the PIF4 gene. We propose a model where warm-temperature-activated PIF4 binds and represses SPCH expression to restrict stomatal production at elevated temperatures. Our work identifies a molecular link connecting high-temperature signaling and stomatal development and reveals a direct mechanism by which production of a specific cell lineage can be controlled by a broadly expressed environmental signaling factor. Copyright © 2018 Elsevier Ltd. All rights reserved.

The impact of elevated CO2 and temperature on grain quality of rice grown under open-air field conditions.

PubMed

Jing, Liquan; Wang, Juan; Shen, Shibo; Wang, Yunxia; Zhu, Jianguo; Wang, Yulong; Yang, Lianxin

2016-08-01

Rising atmospheric CO2 is accompanied by global warming. However, interactive effects of elevated CO2 and temperature have not been well studied on grain quality of rice. A japonica cultivar was grown in the field using a free-air CO2 enrichment facility in combination with a canopy air temperature increase system in 2014. The gas fumigation (200 µmol mol(-1) above ambient CO2 ) and temperature increase (1 °C above ambient air temperature) were performed from tillering until maturity. Compared with the control (ambient CO2 and air temperature), elevated CO2 increased grain length and width as well as grain chalkiness but decreased protein concentrations. In contrast, the increase in canopy air temperature had less effect on these parameters except for grain chalkiness. The starch pasting properties of rice flour and taste analysis of cooked rice indicated that the palatability of rice was improved by CO2 and/or temperature elevation, with the combination of the two treatments showing the most significant changes compared with ambient rice. It is concluded that projected CO2 in 2050 may have larger effects on rice grain quality than the projected temperature increase. Although deterioration in milling suitability, grain appearance and nutritional quality can be expected, the taste of cooked rice might be better in the future environment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

The Black Student's Quest for Identity and Self Determination

ERIC Educational Resources Information Center

Colquit, Jesse L.

1976-01-01

The rising expectations and aspirations of black students in their quest for identity and self determination have given rise to their rejection of the dominant culture's definition of the black man. Top priorities as perceived by blacks in legitimizing their manhood are presented. (Author)

The impact of thermal pollution on benthic foraminiferal assemblages in the SE Mediterranean shore (Israel) as an analog to global warming

NASA Astrophysics Data System (ADS)

Arieli, Ruthie Nina; Almogi-Labin, Ahuva; Abramovich, Sigal; Herut, Barak

2010-05-01

Scientific and public awareness to global warming increased significantly lately. In the Mediterranean Sea the current rate of warming stands at 0.028 °C/year in accordance with the forecast of global warming of 0.2 °C per decade. The aim of this study is to examine the effects of locally elevated vs. natural SST on benthic foraminifera, which are known to be sensitive bioindicators of environmental change. The thermal patch originating from the "Orot Rabin" power plant off the coast of Israel was chosen as a sampling area for this research since it presents a unique small-scale analog for expected future rise in SST. Ten monthly sampling campaigns were performed during a period of one year in 4 stations located along a temperature gradient of approximately 10 °C, from the discharge site of the heated seawater to a few kilometers south. Benthic foraminifera were collected from a shoreface complex of macroalgae and sediments trapped within. The SST varied between winter, 25/18 °C and summer, 36/31 °C along the transect. During the summer, the addition of the temperature anomaly to the already extreme summer temperatures becomes a biologically threat. The natural seasonal variability, depicted best by station 4 located beyond the thermal patch, shows that foraminifera reach maximal abundance in winter and spring. A significant negative correlation was found between SST in all stations and benthic foraminiferal assemblage characteristics. The abundance, species richness and species diversity show negative correlation with the SST anomaly throughout most of the sampling period, though the species diversity was not as significant as the abundance. The total foraminiferal abundance was significantly lower at the thermally polluted stations, especially during the summer, but also throughout the entire year, indicating that the thermal pollution has a detrimental effect on benthic foraminifera, irrelevant to the natural cyclic changes in SST. The foraminiferal abundances decrease drastically as the SST rises, reaching minimal abundances when the SST rises above 30 °C, indicating that this temperature may be a critical threshold above which foraminiferal growth and reproduction are severely retarded. Species richness reached extremely low values at the thermally polluted stations during the summer, with a minimum of 3 species compared to a maximum of 24 in the natural, unaffected station 4. This indicates that some species have adapted to the elevated temperatures better than others. The foraminiferal assemblage, composed mostly of epiphytic species, contains a total of 42 species with six species dominating the assemblage. Out of the six dominant species Rosalina globularis, Tretomphalus bulloides and Textularia agglutinans show a clear preference to the winter months, while species belonging Lachlanella reach maximum abundances in spring and Pararotalia spinigera in summer. The miliolids, Lachlanella sp. 1 and sp. 2 seem to have high tolerance to the elevated SST and even survived the most extreme summer temperatures at the thermally polluted stations. In this research we show that even a rise, as small as 2 °C, in SST can have serious ramifications on the benthic community characteristics living in the near shore environment. If foraminifera are affected to such an extent it is not unlikely that other more developed marine creatures will be negatively affected as well, either directly by the rise in SST or via the decrease in organisms lower down the marine food chain, such as foraminifera.

Intensifying drought eliminates the expected benefits of elevated [CO2] for soybean

USDA-ARS?s Scientific Manuscript database

Stimulation of C3 crop yield by rising [CO2] is widely expected to counteract crop losses to greater drought this century. But these expectations come from sparse field trials that have been biased towards mesic growth conditions. This eight-year study used precipitation manipulations and year-to-ye...

A measurement and modeling study of temperature in living and fixed tissue during and after radiofrequency exposure.

PubMed

Bermingham, Jacqueline F; Chen, Yuen Y; McIntosh, Robert L; Wood, Andrew W

2014-04-01

Fluorescent intensity of the dye Rhodamine-B (Rho-B) decreases with increasing temperature. We show that in fresh rat brain tissue samples in a custom-made radiofrequency (RF) tissue exposure device, temperature rise due to RF radiation as measured by absorbed dye correlates well with temperature measured nearby by fiber optic probes. Estimates of rate of initial temperature rise (using both probe measurement and the dye method) accord well with estimates of local specific energy absorption rate (SAR). We also modeled the temperature characteristics of the exposure device using combined electromagnetic and finite-difference thermal modeling. Although there are some differences in the rate of cooling following cessation of RF exposure, there is reasonable agreement between modeling and both probe measurement and dye estimation of temperature. The dye method also permits measurement of regional temperature rise (due to RF). There is no clear evidence of local differential RF absorption, but further refinement of the method may be needed to fully clarify this issue. © 2014 Wiley Periodicals, Inc.

Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures

PubMed Central

2012-01-01

Background One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating. Methods A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip. Results A maximum temperature rise of 22.4°C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2°C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8°C. Conclusion Up to a maximum of 22.4°C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip system can be used to increase MR safety of EP catheters by suppressing the effects of unwanted passive catheter heating due to RF exposure from the MR scanner. PMID:22296883

Reconciling anthropogenic climate change with observed temperature 1998-2008.

PubMed

Kaufmann, Robert K; Kauppi, Heikki; Mann, Michael L; Stock, James H

2011-07-19

Given the widely noted increase in the warming effects of rising greenhouse gas concentrations, it has been unclear why global surface temperatures did not rise between 1998 and 2008. We find that this hiatus in warming coincides with a period of little increase in the sum of anthropogenic and natural forcings. Declining solar insolation as part of a normal eleven-year cycle, and a cyclical change from an El Nino to a La Nina dominate our measure of anthropogenic effects because rapid growth in short-lived sulfur emissions partially offsets rising greenhouse gas concentrations. As such, we find that recent global temperature records are consistent with the existing understanding of the relationship among global surface temperature, internal variability, and radiative forcing, which includes anthropogenic factors with well known warming and cooling effects.

Mechanism for the occurrence of paramagnetic planes within magnetically ordered cerium systems

NASA Astrophysics Data System (ADS)

Kioussis, Nicholas; Cooper, Bernard R.; Banerjea, Amitava

1988-11-01

Hybridization of moderately delocalized f electrons with band electrons gives rise to a highly anisotropic two-ion interaction. Previously it has been shown that such an interaction explains the experimentally observed unusual magnetic behavior of CeBi, yielding a phase transition from a higher-temperature type-I (↑↓) to a lower-temperature type-IA (↑↑↓↓) antiferromagnetic structure. If the hybridization-mediated interaction is the key to understanding the magnetic behavior of such moderately delocalized f-electron systems, we should expect to be able to understand on this basis the even more unusual magnetic behavior of CeSb. In CeSb, there is a sequence of magnetic structures in which the higher-temperature structures involve a periodic stacking of paramagnetic \\{001\\} planes alternating with magnetically ordered \\{001\\} planes of [001]-moment alignment. In this paper we show that such a coexistence of paramagnetic and magnetically ordered Ce3+ sites can be understood on the basis of the hybridization-mediated interionic interaction when there are cubic crystal-field (CF) interactions of comparable strength. The tendency to form paramagnetic planes is found to increase with increasing CF strength (Γ7 ground state); and the stability of the up-down paramagnetic plane arrangement at high temperatures is shown to arise from the reconciliation of the magnetic ordering with the CF interactions. We also find that for a certain range of parameters a different novel situation occurs, with a fully nonmagnetic (singlet) ground state for the Ce3+ ion. This singlet state is not Kondo-like, and occurs in such a way that the system would be expected to fluctuate between two differently polarized states, one of which is the singlet state.

Climate change and economic growth: a heterogeneous panel data approach.

PubMed

Sequeira, Tiago Neves; Santos, Marcelo Serra; Magalhães, Manuela

2018-05-31

Climate change is a global phenomenon. Its impact on economic growth must therefore be analyzed in accordance with its (time-varying) common effects. We present an econometric analysis that evaluates this effect taking into account its global nature. Contrary to previous evidence that ignores the global effects, we obtain that the rising temperature has not decreased growth in real GDP per capita in the second half of the twentieth century for the world countries. However, we obtain a negative effect of rising temperatures and a positive effect of rising precipitation in poor countries. This positive effect of rising precipitation is also confirmed for hot and temperate countries.

Metabolic heating and the prediction of sex ratios for green turtles (Chelonia mydas).

PubMed

Broderick, A C; Godley, B J; Hays, G C

2001-01-01

We compared incubation temperatures in nests (n=32) of the green turtle (Chelonia mydas) on Ascension Island in relation to sand temperatures of control sites at nest depth. Intrabeach thermal variation was low, whereas interbeach thermal variation was high in both control and nest sites. A marked rise in temperature was recorded in nests from 30% to 40% of the way through the incubation period and attributed to metabolic heating. Over the entire incubation period, metabolic heating accounted for a mean rise in temperature of between 0.07 degrees and 2.86 degrees C within nests. During the middle third of incubation, when sex is thought to be determined, this rise in temperature ranged between 0.07 degrees and 2.61 degrees C. Metabolic heating was related to both the number of eggs laid and the total number of hatchlings/embryos produced in a clutch. For 32 clutches in which temperature was recorded, we estimate that metabolic heating accounted for a rise of up to 30% in the proportion of females produced within different clutches. Previous studies have dismissed any effect of metabolic heating on the sex ratio of marine turtle hatchlings. Our results imply that metabolic heating needs to be considered when estimating green turtle hatchling sex ratios.

Operation of MRO's High Resolution Imaging Science Experiment (HiRISE): Maximizing Science Participation

NASA Technical Reports Server (NTRS)

Eliason, E.; Hansen, C. J.; McEwen, A.; Delamere, W. A.; Bridges, N.; Grant, J.; Gulich, V.; Herkenhoff, K.; Keszthelyi, L.; Kirk, R.

2003-01-01

Science return from the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) will be optimized by maximizing science participation in the experiment. MRO is expected to arrive at Mars in March 2006, and the primary science phase begins near the end of 2006 after aerobraking (6 months) and a transition phase. The primary science phase lasts for almost 2 Earth years, followed by a 2-year relay phase in which science observations by MRO are expected to continue. We expect to acquire approx. 10,000 images with HiRISE over the course of MRO's two earth-year mission. HiRISE can acquire images with a ground sampling dimension of as little as 30 cm (from a typical altitude of 300 km), in up to 3 colors, and many targets will be re-imaged for stereo. With such high spatial resolution, the percent coverage of Mars will be very limited in spite of the relatively high data rate of MRO (approx. 10x greater than MGS or Odyssey). We expect to cover approx. 1% of Mars at approx. 1m/pixel or better, approx. 0.1% at full resolution, and approx. 0.05% in color or in stereo. Therefore, the placement of each HiRISE image must be carefully considered in order to maximize the scientific return from MRO. We believe that every observation should be the result of a mini research project based on pre-existing datasets. During operations, we will need a large database of carefully researched 'suggested' observations to select from. The HiRISE team is dedicated to involving the broad Mars community in creating this database, to the fullest degree that is both practical and legal. The philosophy of the team and the design of the ground data system are geared to enabling community involvement. A key aspect of this is that image data will be made available to the planetary community for science analysis as quickly as possible to encourage feedback and new ideas for targets.

Oxygen Mass Flow Rate Generated for Monitoring Hydrogen Peroxide Stability

NASA Technical Reports Server (NTRS)

Ross, H. Richard

2002-01-01

Recent interest in propellants with non-toxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because peroxide is sensitive to contaminants, material interactions, stability and storage issues, monitoring decomposition rates is important. Stennis Space Center (SSC) uses thermocouples to monitor bulk fluid temperature (heat evolution) to determine reaction rates. Unfortunately, large temperature rises are required to offset the heat lost into the surrounding fluid. Also, tank penetration to accomodate a thermocouple can entail modification of a tank or line and act as a source of contamination. The paper evaluates a method for monitoring oxygen evolution as a means to determine peroxide stability. Oxygen generation is not only directly related to peroxide decomposition, but occurs immediately. Measuring peroxide temperature to monitor peroxide stability has significant limitations. The bulk decomposition of 1% / week in a large volume tank can produce in excess of 30 cc / min. This oxygen flow rate corresponds to an equivalent temperature rise of approximately 14 millidegrees C, which is difficult to measure reliably. Thus, if heat transfer were included, there would be no temperature rise. Temperature changes from the surrounding environment and heat lost to the peroxide will also mask potential problems. The use of oxygen flow measurements provides an ultra sensitive technique for monitoring reaction events and will provide an earlier indication of an abnormal decomposition when compared to measuring temperature rise.

Temperature control and measurement with tunable femtosecond optical tweezers

NASA Astrophysics Data System (ADS)

Mondal, Dipankar; Goswami, Debabrata

2016-09-01

We present the effects of wavelength dependent temperature rise in a femtosecond optical tweezers. Our experiments involve the femtosecond trapping laser tunable from 740-820 nm at low power 25 mW to cause heating in the trapped volume within a homogeneous solution of sub micro-molar concentration of IR dye. The 780 nm high repetition rate laser acts as a resonant excitation source which helps to create the local heating effortlessly within the trapping volume. We have used both position autocorrelation and equipartion theorem to evaluate temperature at different wavelength having different absorption coefficient. Fixing the pulse width in the temporal domain gives constant bandwidth at spatial domain, which makes our system behave as a tunable temperature rise device with high precision. This observation leads us to calculate temperature as well as viscosity within the vicinity of the trapping zone. A mutual energy transfer occurs between the trapped bead and solvents that leads to transfer the thermal energy of solvents into the kinetic energy of the trap bead and vice-versa. Thus hot solvated molecules resulting from resonant and near resonant excitation of trapping wavelength can continuously dissipate heat to the trapped bead which will be reflected on frequency spectrum of Brownian noise exhibited by the bead. Temperature rise near the trapping zone can significantly change the viscosity of the medium. We observe temperature rise profile according to its Gaussian shaped absorption spectrum with different wavelength.

76 FR 64924 - Updating State Residential Building Energy Efficiency Codes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-19

...) considers high-rise (greater than three stories) multifamily residential buildings and hotel, motel, and..., duplexes, townhouses, row houses, and low-rise multifamily buildings (not greater than three stories) such... pumps as compared to other electric heating technologies, this code change is expected to increase the...

The endothermic ATP hydrolysis and crossbridge attachment steps drive the increase of force with temperature in isometric and shortening muscle

PubMed Central

Offer, Gerald; Ranatunga, K W

2015-01-01

The isometric tetanic tension of skeletal muscle increases with temperature because attached crossbridge states bearing a relatively low force convert to those bearing a higher force. It was previously proposed that the tension-generating step(s) in the crossbridge cycle was highly endothermic and was therefore itself directly targeted by changes in temperature. However, this did not explain why a rapid rise in temperature (a temperature jump) caused a much slower rate of rise of tension than a rapid length step. This led to suggestions that the step targeted by a temperature rise is not the tension-generating step but is an extra step in the attached pathway of the crossbridge cycle, perhaps located on a parallel pathway. This enigma has been a major obstacle to a full understanding of the operation of the crossbridge cycle. We have now used a previously developed mechano-kinetic model of the crossbridge cycle in frog muscle to simulate the temperature dependence of isometric tension and shortening velocity. We allowed all five steps in the cycle to be temperature-sensitive. Models with different starting combinations of enthalpy changes and activation enthalpies for the five steps were refined by downhill simplex runs and scored by their ability to fit experimental data on the temperature dependence of isometric tension and the relationship between force and shortening velocity in frog muscle. We conclude that the first tension-generating step may be weakly endothermic and that the rise of tension with temperature is largely driven by the preceding two strongly endothermic steps of ATP hydrolysis and attachment of M.ADP.Pi to actin. The refined model gave a reasonable fit to the available experimental data and after a temperature jump the overall rate of tension rise was much slower than after a length step as observed experimentally. The findings aid our understanding of the crossbridge cycle by showing that it may not be necessary to include an additional temperature-sensitive step. PMID:25564737

Irreversible climate change due to carbon dioxide emissions.

PubMed

Solomon, Susan; Plattner, Gian-Kasper; Knutti, Reto; Friedlingstein, Pierre

2009-02-10

The severity of damaging human-induced climate change depends not only on the magnitude of the change but also on the potential for irreversibility. This paper shows that the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop significantly for at least 1,000 years. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450-600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the "dust bowl" era and inexorable sea level rise. Thermal expansion of the warming ocean provides a conservative lower limit to irreversible global average sea level rise of at least 0.4-1.0 m if 21st century CO(2) concentrations exceed 600 ppmv and 0.6-1.9 m for peak CO(2) concentrations exceeding approximately 1,000 ppmv. Additional contributions from glaciers and ice sheet contributions to future sea level rise are uncertain but may equal or exceed several meters over the next millennium or longer.

Irreversible climate change due to carbon dioxide emissions

PubMed Central

Solomon, Susan; Plattner, Gian-Kasper; Knutti, Reto; Friedlingstein, Pierre

2009-01-01

The severity of damaging human-induced climate change depends not only on the magnitude of the change but also on the potential for irreversibility. This paper shows that the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop significantly for at least 1,000 years. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450–600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the “dust bowl” era and inexorable sea level rise. Thermal expansion of the warming ocean provides a conservative lower limit to irreversible global average sea level rise of at least 0.4–1.0 m if 21st century CO2 concentrations exceed 600 ppmv and 0.6–1.9 m for peak CO2 concentrations exceeding ≈1,000 ppmv. Additional contributions from glaciers and ice sheet contributions to future sea level rise are uncertain but may equal or exceed several meters over the next millennium or longer. PMID:19179281

Deglacial temperature history of West Antarctica

PubMed Central

Clow, Gary D.; Steig, Eric J.; Buizert, Christo; Fudge, T. J.; Koutnik, Michelle; Waddington, Edwin D.; Alley, Richard B.

2016-01-01

The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth’s climate responds to various forcings, including a rise in atmospheric CO2. This transition has left a direct thermal remnant in the polar ice sheets, where the exceptional purity and continual accumulation of ice permit analyses not possible in other settings. For Antarctica, the deglacial warming has previously been constrained only by the water isotopic composition in ice cores, without an absolute thermometric assessment of the isotopes’ sensitivity to temperature. To overcome this limitation, we measured temperatures in a deep borehole and analyzed them together with ice-core data to reconstruct the surface temperature history of West Antarctica. The deglacial warming was 11.3±1.8∘C, approximately two to three times the global average, in agreement with theoretical expectations for Antarctic amplification of planetary temperature changes. Consistent with evidence from glacier retreat in Southern Hemisphere mountain ranges, the Antarctic warming was mostly completed by 15 kyBP, several millennia earlier than in the Northern Hemisphere. These results constrain the role of variable oceanic heat transport between hemispheres during deglaciation and quantitatively bound the direct influence of global climate forcings on Antarctic temperature. Although climate models perform well on average in this context, some recent syntheses of deglacial climate history have underestimated Antarctic warming and the models with lowest sensitivity can be discounted. PMID:27911783

Combustor technology for future small gas turbine aircraft

NASA Technical Reports Server (NTRS)

Lyons, Valerie J.; Niedzwiecki, Richard W.

1993-01-01

Future engine cycles proposed for advanced small gas turbine engines will increase the severity of the operating conditions of the combustor. These cycles call for increased overall engine pressure ratios which increase combustor inlet pressure and temperature. Further, the temperature rise through the combustor and the corresponding exit temperature also increase. Future combustor technology needs for small gas turbine engines is described. New fuel injectors with large turndown ratios which produce uniform circumferential and radial temperature patterns will be required. Uniform burning will be of greater importance because hot gas temperatures will approach turbine material limits. The higher combustion temperatures and increased radiation at high pressures will put a greater heat load on the combustor liners. At the same time, less cooling air will be available as more of the air will be used for combustion. Thus, improved cooling concepts and/or materials requiring little or no direct cooling will be required. Although presently there are no requirements for emissions levels from small gas turbine engines, regulation is expected in the near future. This will require the development of low emission combustors. In particular, nitrogen oxides will increase substantially if new technologies limiting their formation are not evolved and implemented. For example, staged combustion employing lean, premixed/prevaporized, lean direct injection, or rich burn-quick quench-lean burn concepts could replace conventional single stage combustors.

The long-term trends (1982-2006) in vegetation greenness of the alpine ecosystem in the Qinghai-Tibetan Plateau

USGS Publications Warehouse

Zhang, Li; Guo, Huadong; Wang, Cuizhen; Ji, Lei; Li, Jing; Wang, Kun; Dai, Lin

2014-01-01

The increased rate of annual temperature in the Qinghai-Tibetan Plateau exceeded all other areas of the same latitude in recent decades. The influence of the warming climate on the alpine ecosystem of the plateau was distinct. An analysis of alpine vegetation under changes in climatic conditions was conducted in this study. This was done through an examination of vegetation greenness and its relationship with climate variability using the Advanced Very High Resolution Radiometer satellite imagery and climate datasets. Vegetation in the plateau experienced a positive trend in greenness, with 18.0 % of the vegetated areas exhibiting significantly positive trends, which were primarily located in the eastern and southwestern parts of the plateau. In grasslands, 25.8 % of meadows and 14.1 % of steppes exhibited significant upward trends. In contrast, the broadleaf forests experienced a trend of degradation. Temperature, particularly summer temperature, was the primary factor promoting the vegetation growth in the plateau. The wetter and warmer climate in the east contributed to the favorable conditions for vegetation. The alpine meadow was mostly sensitive to temperature, while the steppes were sensitive to both temperature and precipitation. Although a warming climate was expected to be beneficial to vegetation growth in the alpine region, the rising temperature coupled with reduced precipitation in the south did not favor vegetation growth due to low humidity and poor soil moisture conditions.

Deglacial temperature history of West Antarctica.

PubMed

Cuffey, Kurt M; Clow, Gary D; Steig, Eric J; Buizert, Christo; Fudge, T J; Koutnik, Michelle; Waddington, Edwin D; Alley, Richard B; Severinghaus, Jeffrey P

2016-12-13

The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth's climate responds to various forcings, including a rise in atmospheric CO 2 This transition has left a direct thermal remnant in the polar ice sheets, where the exceptional purity and continual accumulation of ice permit analyses not possible in other settings. For Antarctica, the deglacial warming has previously been constrained only by the water isotopic composition in ice cores, without an absolute thermometric assessment of the isotopes' sensitivity to temperature. To overcome this limitation, we measured temperatures in a deep borehole and analyzed them together with ice-core data to reconstruct the surface temperature history of West Antarctica. The deglacial warming was [Formula: see text]C, approximately two to three times the global average, in agreement with theoretical expectations for Antarctic amplification of planetary temperature changes. Consistent with evidence from glacier retreat in Southern Hemisphere mountain ranges, the Antarctic warming was mostly completed by 15 kyBP, several millennia earlier than in the Northern Hemisphere. These results constrain the role of variable oceanic heat transport between hemispheres during deglaciation and quantitatively bound the direct influence of global climate forcings on Antarctic temperature. Although climate models perform well on average in this context, some recent syntheses of deglacial climate history have underestimated Antarctic warming and the models with lowest sensitivity can be discounted.

Compartment-specific transcriptomics in a reef-building coral exposed to elevated temperatures

PubMed Central

Mayfield, Anderson B; Wang, Yu-Bin; Chen, Chii-Shiarng; Lin, Chung-Yen; Chen, Shu-Hwa

2014-01-01

Although rising ocean temperatures threaten scleractinian corals and the reefs they construct, certain reef corals can acclimate to elevated temperatures to which they are rarely exposed in situ. Specimens of the model Indo-Pacific reef coral Pocillopora damicornis collected from upwelling reefs of Southern Taiwan were previously found to have survived a 36-week exposure to 30°C, a temperature they encounter infrequently and one that can elicit the breakdown of the coral–dinoflagellate (genus Symbiodinium) endosymbiosis in many corals of the Pacific Ocean. To gain insight into the subcellular pathways utilized by both the coral hosts and their mutualistic Symbiodinium populations to acclimate to this temperature, mRNAs from both control (27°C) and high (30°C)-temperature samples were sequenced on an Illumina platform and assembled into a 236 435-contig transcriptome. These P. damicornis specimens were found to be ∼60% anthozoan and 40% microbe (Symbiodinium, other eukaryotic microbes, and bacteria), from an mRNA-perspective. Furthermore, a significantly higher proportion of genes from the Symbiodinium compartment were differentially expressed after two weeks of exposure. Specifically, at elevated temperatures, Symbiodinium populations residing within the coral gastrodermal tissues were more likely to up-regulate the expression of genes encoding proteins involved in metabolism than their coral hosts. Collectively, these transcriptome-scale data suggest that the two members of this endosymbiosis have distinct strategies for acclimating to elevated temperatures that are expected to characterize many of Earth's coral reefs in the coming decades. PMID:25354956

Fiber optic temperature sensor gives rise to thermal analysis in complex product design

NASA Astrophysics Data System (ADS)

Cheng, Andrew Y. S.; Pau, Michael C. Y.

1996-09-01

A computer-adapted fiber-optic temperature sensing system has been developed which aims to study both the theoretical aspect of fiber temperature sensing and the experimental aspect of such system. The system consists of a laser source, a fiber sensing element, an electronic fringes counting device, and an on-line personal computer. The temperature measurement is achieved by the conventional double beam fringe counting method with optical path length changes in the sensing beam due to the fiber expansion. The system can automatically measure the temperature changes in a sensing fiber arm which provides an insight of the heat generation and dissipation of the measured system. Unlike the conventional measuring devices such as thermocouples or solid state temperature sensors, the fiber sensor can easily be wrapped and shaped to fit the surface of the measuring object or even inside a molded plastic parts such as a computer case, which gives much more flexibility and applicability to the analysis of heat generation and dissipation in the operation of these machine parts. The reference beam is being set up on a temperature controlled optical bench to facilitate high sensitivity and high temperature resolution. The measuring beam has a motorized beam selection device for multiple fiber beam measurement. The project has been demonstrated in the laboratory and the system sensitivity and resolution are found to be as high as 0.01 degree Celsius. It is expected the system will find its application in many design studies which require thermal budgeting.

[Evaluation of Artificial Hip Joint with Radiofrequency Heating Issues during MRI Examination: A Comparison between 1.5 T and 3 T].

PubMed

Yamazaki, Masaru; Ideta, Takahiro; Kudo, Sadahiro; Nakazawa, Masami

2016-06-01

In magnetic resonance imaging (MRI), when radiofrequency (RF) is irradiated to a subject with metallic implant, it can generate heat by RF irradiation. Recently 3 T MRI scanner has spread widely and imaging for any regions of whole body has been conducted. However specific absorption rate (SAR) of 3 T MRI becomes approximately four times as much as the 1.5 T, which can significantly affect the heat generation of metallic implants. So, we evaluated RF heating of artificial hip joints in different shapes and materials in 1.5 T and 3 T MRI. Three types of artificial hip joints made of stainless alloy, titanium alloy and cobalt chrome alloy were embedded in the human body-equivalent phantom respectively and their temperature change were measured for twenty minutes by 1.5 T and 3 T MRI. The maximum temperature rise was observed at the bottom head in all of three types of artificial hip joints, the rise being 12°C for stainless alloy, 11.9°C for titanium alloy and 6.1°C for cobalt chrome alloy in 1.5 T. The temperature rise depended on SAR and the increase of SAR had a good linear relationship with the temperature rise. It was found from the result that the RF heating of metallic implants can take place in various kinds of material and the increase of SAR has a good linear relationship with the temperature rise. This experience shows that reduction of SAR can decrease temperature of metallic implants.

Petit-spot as definitive evidence for partial melting in the asthenosphere caused by CO2

NASA Astrophysics Data System (ADS)

Machida, Shiki; Kogiso, Tetsu; Hirano, Naoto

2017-02-01

The deep carbon cycle plays an important role on the chemical differentiation and physical properties of the Earth's mantle. Especially in the asthenosphere, seismic low-velocity and high electrical conductivity due to carbon dioxide (CO2)-induced partial melting are expected but not directly observed. Here we discuss the experimental results relevant to the genesis of primitive CO2-rich alkali magma forming petit-spot volcanoes at the deformation front of the outer rise of the northwestern Pacific plate. The results suggest that primitive melt last equilibrated with depleted peridotite at 1.8-2.1 GPa and 1,280-1,290 °C. Although the equilibration pressure corresponds to the pressure of the lower lithosphere, by considering an equilibration temperature higher than the solidus in the volatile-peridotite system along with the temperature of the lower lithosphere, we conclude that CO2-rich silicate melt is always produced in the asthenosphere. The melt subsequently ascends into and equilibrates with the lower lithosphere before eruption.

Reduction of temperature rise in high-speed photography

NASA Technical Reports Server (NTRS)

Slater, Howard A.

1987-01-01

Information is provided on filtration with glass and infrared absorbing and reflecting filters. Glass and infrared filtration is a simple and effective method to reduce the radiation heat transfer associated with continuous high intensity tungsten lamps. The results of a filtration experiment are explained. The figures provide starting points for quantifying the effectiveness of various filters and associated light intensities. The combination of a spectrally selective reflector (hot or cold mirror) based on multilayer thin film principles and heat absorbing or infrared opaque glass results in the maximum reduction in temperature rise with a minimum of incident light loss. Use is recommended of a voltage regulator to further control temperature rise and incident light values.

Reduction of temperature rise in high-speed photography

NASA Technical Reports Server (NTRS)

Slater, Howard A.

1988-01-01

Information is provided on filtration with glass and infrared absorbing and reflecting filters. Glass and infrared filtration is a simple and effective method to reduce the radiation heat transfer associated with continuous high intensity tungsten lamps. The results of a filtration experiment are explained. The figures provide starting points for quantifying the effectiveness of various filters and associated light intensities. The combination of a spectrally selective reflector (hot or cold mirror) based on multilayer thin film principles and heat absorbing or infrared opaque glass results in the maximum reduction in temperature rise with a minimum of incident light loss. Use is recommended of a voltage regulator to further control temperature rise and incident light values.

Dissipation of mechanical work and temperature rise in AS4/PEEK thermoplastic composite

NASA Technical Reports Server (NTRS)

Georgiou, I.; Sun, C. T.

1990-01-01

The dissipated mechanical work per cycle of sinusoidal stress in the thermoplastic composite material AS4/PEEK was measured as a function of stress amplitude for fixed frequency and fiber orientation. The experimental result shows that the dissipated work per cycle is proportional to the square of the stress amplitude. Using the concept of the equivalent isotropic material, it is shown that the relaxation modulus satisfies a proportionality condition. Also, the rate of temperature rise due to sinusoidal stresses has been measured as a function of stress amplitude. The result shows that the rate of temperature rise is not proportional to the square of the stress amplitude.

Committed sea-level rise under the Paris Agreement and the legacy of delayed mitigation action.

PubMed

Mengel, Matthias; Nauels, Alexander; Rogelj, Joeri; Schleussner, Carl-Friedrich

2018-02-20

Sea-level rise is a major consequence of climate change that will continue long after emissions of greenhouse gases have stopped. The 2015 Paris Agreement aims at reducing climate-related risks by reducing greenhouse gas emissions to net zero and limiting global-mean temperature increase. Here we quantify the effect of these constraints on global sea-level rise until 2300, including Antarctic ice-sheet instabilities. We estimate median sea-level rise between 0.7 and 1.2 m, if net-zero greenhouse gas emissions are sustained until 2300, varying with the pathway of emissions during this century. Temperature stabilization below 2 °C is insufficient to hold median sea-level rise until 2300 below 1.5 m. We find that each 5-year delay in near-term peaking of CO 2 emissions increases median year 2300 sea-level rise estimates by ca. 0.2 m, and extreme sea-level rise estimates at the 95th percentile by up to 1 m. Our results underline the importance of near-term mitigation action for limiting long-term sea-level rise risks.

Application of a temperature-dependent fluorescent dye (Rhodamine B) to the measurement of radiofrequency radiation-induced temperature changes in biological samples.

PubMed

Chen, Yuen Y; Wood, Andrew W

2009-10-01

We have applied a non-contact method for studying the temperature changes produced by radiofrequency (RF) radiation specifically to small biological samples. A temperature-dependent fluorescent dye, Rhodamine B, as imaged by laser scanning confocal microscopy (LSCM) was used to do this. The results were calibrated against real-time temperature measurements from fiber optic probes, with a calibration factor of 3.4% intensity change degrees C(-1) and a reproducibility of +/-6%. This non-contact method provided two-dimensional and three-dimensional images of temperature change and distributions in biological samples, at a spatial resolution of a few micrometers and with an estimated absolute precision of around 1.5 degrees C, with a differential precision of 0.4 degree C. Temperature rise within tissue was found to be non-uniform. Estimates of specific absorption rate (SAR) from absorbed power measurements were greater than those estimated from rate of temperature rise, measured at 1 min intervals, probably because this interval is too long to permit accurate estimation of initial temperature rise following start of RF exposure. Future experiments will aim to explore this.

Solar heating of GaAs nanowire solar cells.

PubMed

Wu, Shao-Hua; Povinelli, Michelle L

2015-11-30

We use a coupled thermal-optical approach to model the operating temperature rise in GaAs nanowire solar cells. We find that despite more highly concentrated light absorption and lower thermal conductivity, the overall temperature rise in a nanowire structure is no higher than in a planar structure. Moreover, coating the nanowires with a transparent polymer can increase the radiative cooling power by 2.2 times, lowering the operating temperature by nearly 7 K.

Solar heating of GaAs nanowire solar cells

DOE PAGES

Wu, Shao-Hua; Povinelli, Michelle L.

2015-09-25

We use a coupled thermal-optical approach to model the operating temperature rise in GaAs nanowire solar cells. Our findings show that despite more highly concentrated light absorption and lower thermal conductivity, the overall temperature rise in a nanowire structure is no higher than in a planar structure. Moreover, coating the nanowires with a transparent polymer can increase the radiative cooling power by 2.2 times, lowering the operating temperature by nearly 7 K.

Assessment To Promote Deep Learning: Insight from AAHE's 2000 and 1999 Assessment Conferences. Major Addresses from "Rising Expectations for Assessment: Can We Deliver?" AAHE Assessment Conference (Charlotte, North Carolina, June 14-18, 2000) [and] Highlights of Plenary Addresses from "Assessment as Evidence of Learning: Serving Student and Society," AAHE Assessment Conference (Denver, Colorado, June 13-16, 1999).

ERIC Educational Resources Information Center

Suskie, Linda, Ed.

Papers from two conferences explore efforts to meet rising expectations for higher education through fair and honest assessment. The papers from the 2000 conference are: (1) "A Conversation with Jorge Klor de Alva" (interviewed by Gail Mellow); (2) "Promoting Deep Learning through Teaching and Assessment" (Noel Entwistle); (3)…

Influence of nitromethane concentration on ignition energy and explosion parameters in gaseous nitromethane/air mixtures.

PubMed

Zhang, Qi; Li, Wei; Lin, Da-Chao; He, Ning; Duan, Yun

2011-01-30

The aim of this paper is to provide new experimental data of the minimum ignition energy (MIE) of gaseous nitromethane/air mixtures to discuss the explosion pressure and the flame temperature as a function of nitromethane concentration. Observations on the influence of nitromethane concentration on combustion pressure and temperature through the pressure and temperature measure system show that peak temperature (the peak of combustion temperature wave) is always behind peak pressure (the peak of the combustion pressure wave) in arrival time, the peak combustion pressure of nitromethane increases in the range of its volume fraction 10-40% as the concentration of nitromethane increases, and it slightly decreases in the range of 40-50%. The maximum peak pressure is equal to 0.94 MPa and the minimum peak pressure 0.58 MPa. Somewhat similar to the peak pressure, the peak combustion temperature increases with the volume fraction of nitromethane in the range of 10-40%, and slightly decreases in 40-50%. The maximum peak temperature is 1340 °C and the minimum 860 °C. The combustion temperature rise rate increases with the concentration of nitromethane in 10-30%, while decreases in 30-50% and its maximum value of combustion temperature rise rate in 10-50% is 4200 °C/s at the volume fraction of 30%. Influence of the concentration of nitromethane on the combustion pressure rise rate is relatively complicated, and the maximum value of rise rate of combustion pressure wave in 10-50% is 11 MPa/s at the concentration 20%. Copyright © 2010 Elsevier B.V. All rights reserved.

Surprisingly robust projections of soil temperature and moisture for North American drylands in the 21st century

NASA Astrophysics Data System (ADS)

Bradford, J. B.; Schlaepfer, D.; Palmquist, K. A.; Lauenroth, W.

2017-12-01

Climate projections for western North America suggest temperature increases that are relatively consistent across climate models. However, precipitation projections are less consistent, especially in the Southwest, promoting uncertainty about the future of soil moisture and drought. We utilized a daily time-step ecosystem water balance model to characterize soil temperature and moisture patterns at a 10-km resolution across western North America for historical (1980-2010), mid-century (2020-2050), and late century (2070-2100). We simulated soil moisture and temperature under two representative concentration pathways and eleven climate models (selected strategically to represent the range of variability in projections among the full set of models in the CMIP5 database and perform well in hind-cast comparisons for the region), and we use the results to identify areas with robust projections, e.g. areas where the large majority of models agree in the direction of change in long-term average soil moisture or temperature. Rising air temperatures will increase average soil temperatures across western North America and expand the area of mesic and thermic soil temperature regimes while decreasing the area of cryic and frigid regimes. Future soil moisture conditions are relatively consistent across climate models for much of the region, including many areas with variable precipitation trajectories. Consistent projections for drier soils are expected in most of Arizona and New Mexico, similar to previous studies. Other regions with projections for declining soil moisture include the central and southern U.S. Great Plains and large parts of southern British Columbia. By contrast, areas with robust projections for increasing soil moisture include northeastern Montana, southern Alberta and Saskatchewan, and many areas in the intermountain west dominated by big sagebrush. In addition, seasonal moisture patterns in much of the western US drylands are expected to shift toward cool-season water availability, with potentially important consequences for ecosystem structure and function. These results provide a framework for coping with variability in climate projections and assessing climate change impacts on dryland ecosystems.

Climate Change: Life history adaptation by a global whitefly, Bemisia tabaci, with rising temperature and carbon dioxide

USDA-ARS?s Scientific Manuscript database

Introduction: Climate change can have direct and indirect impacts on living organisms. A rise in ambient temperature and elevated carbon dioxide (CO2) concentrations due to global warming may have assorted impacts on arthropods such as altered life cycles, altered reproductive patterns, and change...

Reconciling anthropogenic climate change with observed temperature 1998–2008

PubMed Central

Kaufmann, Robert K.; Kauppi, Heikki; Mann, Michael L.; Stock, James H.

2011-01-01

Given the widely noted increase in the warming effects of rising greenhouse gas concentrations, it has been unclear why global surface temperatures did not rise between 1998 and 2008. We find that this hiatus in warming coincides with a period of little increase in the sum of anthropogenic and natural forcings. Declining solar insolation as part of a normal eleven-year cycle, and a cyclical change from an El Nino to a La Nina dominate our measure of anthropogenic effects because rapid growth in short-lived sulfur emissions partially offsets rising greenhouse gas concentrations. As such, we find that recent global temperature records are consistent with the existing understanding of the relationship among global surface temperature, internal variability, and radiative forcing, which includes anthropogenic factors with well known warming and cooling effects. PMID:21730180

Catalyzed Combustion of Bipropellants for Micro-Spacecraft Propulsion

NASA Technical Reports Server (NTRS)

Schneider, Steven J.; Sung, Chih-Jen; Boyarko, George A.

2003-01-01

This paper addresses the need to understand the physics and chemistry involved in propellant combustion processes in micro-scale combustors for propulsion systems on micro-spacecraft. These spacecraft are planned to have a mass less than 50 kilograms with attitude control estimated to be in the 10 milli-Newton thrust class. These combustors are anticipated to be manufactured using Micro Electrical Mechanical Systems (MEMS) technology and are expected to have diameters approaching the quenching diameter of the propellants. Combustors of this size are expected to benefit significantly from surface catalysis processes. Miniature flame tube apparatus is chosen for this study because microtubes can be easily fabricated from known catalyst materials and their simplicity in geometry can be used in fundamental simulations for validation purposes. Experimentally, we investigated the role of catalytically active surfaces within 0.4 and 0.8 mm internal diameter microtubes, with special emphases on ignition processes in fuel rich gaseous hydrogen and gaseous oxygen. Flame thickness and reaction zone thickness calculations predict that the diameters of our test apparatus are below the quenching diameter of the propellants in sub-atmospheric tests. Temperature and pressure rise in resistively heated platinum and palladium microtubes was used as an indication of exothermic reactions. Specific data on mass flow versus preheat temperature required to achieve ignition are presented. With a plug flow model, the experimental conditions were simulated with detailed gas-phase chemistry, thermodynamic properties, and surface kinetics. Computational results generally support the experimental findings, but suggest an experimental mapping of the exit temperature and composition is needed.

Thermal and electrical transport across a magnetic quantum critical point.

PubMed

Pfau, Heike; Hartmann, Stefanie; Stockert, Ulrike; Sun, Peijie; Lausberg, Stefan; Brando, Manuel; Friedemann, Sven; Krellner, Cornelius; Geibel, Christoph; Wirth, Steffen; Kirchner, Stefan; Abrahams, Elihu; Si, Qimiao; Steglich, Frank

2012-04-25

A quantum critical point (QCP) arises when a continuous transition between competing phases occurs at zero temperature. Collective excitations at magnetic QCPs give rise to metallic properties that strongly deviate from the expectations of Landau's Fermi-liquid description, which is the standard theory of electron correlations in metals. Central to this theory is the notion of quasiparticles, electronic excitations that possess the quantum numbers of the non-interacting electrons. Here we report measurements of thermal and electrical transport across the field-induced magnetic QCP in the heavy-fermion compound YbRh(2)Si(2) (refs 2, 3). We show that the ratio of the thermal to electrical conductivities at the zero-temperature limit obeys the Wiedemann-Franz law for magnetic fields above the critical field at which the QCP is attained. This is also expected for magnetic fields below the critical field, where weak antiferromagnetic order and a Fermi-liquid phase form below 0.07 K (at zero field). At the critical field, however, the low-temperature electrical conductivity exceeds the thermal conductivity by about 10 per cent, suggestive of a non-Fermi-liquid ground state. This apparent violation of the Wiedemann-Franz law provides evidence for an unconventional type of QCP at which the fundamental concept of Landau quasiparticles no longer holds. These results imply that Landau quasiparticles break up, and that the origin of this disintegration is inelastic scattering associated with electronic quantum critical fluctuations--these insights could be relevant to understanding other deviations from Fermi-liquid behaviour frequently observed in various classes of correlated materials.

Global Coastal Exposure due to Sea-level Rise beyond Tipping Points with Multiple Warming Pathways

NASA Astrophysics Data System (ADS)

Tawatari, R.; Iseri, Y.; Kiguchi, M.; Kanae, S.

2016-12-01

Sea-level is observed and estimated to continue rising. In the future, the rise could be abrupt and irreversible in century to millennial timescale even if we conduct strong reduction of greenhouse gas emission. Greenland ice sheet and West Antarctic ice sheet are considered as attributable climate systems which would significantly enhance presently-projected sea-level rise by several meters if global mean temperature passes certain "Tipping points" which would exist around +1-5 degree Celsius above present temperature (1980-1999 average). Therefore, vulnerable coastal low-lying area, especially small islands, deltas or poor developing countries, would suffer from semi-permanent inundation and forced to counteract due to the enhanced sea-level rise. This study estimate range of sea-level rise until the year 2300 and 3000 considering excess of tipping points with using multiple levels of temperature scenarios which consist of excess tipping points and non-excess tipping points pathways. We extract state-of-the-art knowledge of tipping elements from paper reviewing to express reasonable relationship between temperature and abruptly-changing sea-level transition across the ages. This study also calculate coastal exposure globally as affected population, area and asset below the estimated sea-level for each countries with overlaying 30 arc-second gridded topography, population distribution and the sea-level. The result indicates which country would be critically affected if we follow overshooting pathways. Furthermore, this study visualize uncertain coastal exposure due to sea-level rise in the future from the multiple warming pathways. This estimation of possible future beyond tipping point would be useful information for decision-makers to establish new planning of defense, migration or mitigation for the future societies.

Products from the Oxidation of n-Butane from 298 to 735 K Using Either Cl Atom or Thermal Initiation: Formation of Acetone and Acetic Acid-Possible Roaming Reactions?

PubMed

Kaiser, E W; Wallington, T J

2017-11-16

The oxidation of 2-butyl radicals (and to a lesser extent 1-butyl radicals) has been studied over the temperature range of 298-735 K. The reaction of Cl atoms (formed by 360 nm irradiation of Cl 2 ) with n-butane generated the 2-butyl radicals in mixtures of n-C 4 H 10 , O 2 , and Cl 2 at temperatures below 600 K. Above 600 K, 2-butyl radicals were produced by thermal combustion reactions in the absence of chlorine. The yields of the products were measured by gas chromatography using a flame ionization detector. Major products quantified include acetone, acetic acid, acetaldehyde, butanone, 2-butanol, butanal, 1- and 2- chlorobutane, 1-butene, trans-2-butene, and cis-2-butene. At 298 K, the major oxygenated products are those expected from bimolecular reactions of 2-butylperoxy radicals (butanone, 2-butanol, and acetaldehyde). As the temperature rises to 390 K, the butanone decreases while acetaldehyde increases because of the increased rate of 2-butoxy radical decomposition. Acetone and acetic acid first appear in significant yield near 400 K, and these species rise slowly at first and then sharply, peaking near 525 K at yields of ∼25 and ∼20 mol %, respectively. In the same temperature range (400-525 K), butanone, acetaldehyde, and 2-butanol decrease rapidly. This suggests that acetone and acetic acid may be formed by previously unknown reaction channels of the 2-butylperoxy radical, which are in competition with those that lead to butanone, acetaldehyde, and 2-butanol. Above 570 K, the yields of acetone and acetic acid fall rapidly as the yields of the butenes rise. Experiments varying the Cl atom density, which in turn controls the entire radical pool density, were performed in the temperature range of 410-440 K. Decreasing the Cl atom density increased the yields of acetone and acetic acid while the yields of butanone, acetaldehyde, and 2-butanol decreased. This is consistent with the formation of acetone and acetic acid by unimolecular decomposition channels of the 2-butylperoxy radical, which are in competition with the bimolecular channels that form butanone, acetaldehyde, and 2-butanol. Such unimolecular decomposition channels would be unlikely to proceed through conventional transition states because those states would be very constrained. Therefore, the possibility that these decomposition channels proceed via roaming should be considered. In addition, we investigated and were unable to fit our data trends by a simplified ketohydroperoxide mechanism.

Estimating Hardness from the USDC Tool-Bit Temperature Rise

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Sherrit, Stewart

2008-01-01

A method of real-time quantification of the hardness of a rock or similar material involves measurement of the temperature, as a function of time, of the tool bit of an ultrasonic/sonic drill corer (USDC) that is being used to drill into the material. The method is based on the idea that, other things being about equal, the rate of rise of temperature and the maximum temperature reached during drilling increase with the hardness of the drilled material. In this method, the temperature is measured by means of a thermocouple embedded in the USDC tool bit near the drilling tip. The hardness of the drilled material can then be determined through correlation of the temperature-rise-versus-time data with time-dependent temperature rises determined in finite-element simulations of, and/or experiments on, drilling at various known rates of advance or known power levels through materials of known hardness. The figure presents an example of empirical temperature-versus-time data for a particular 3.6-mm USDC bit, driven at an average power somewhat below 40 W, drilling through materials of various hardness levels. The temperature readings from within a USDC tool bit can also be used for purposes other than estimating the hardness of the drilled material. For example, they can be especially useful as feedback to control the driving power to prevent thermal damage to the drilled material, the drill bit, or both. In the case of drilling through ice, the temperature readings could be used as a guide to maintaining sufficient drive power to prevent jamming of the drill by preventing refreezing of melted ice in contact with the drill.

Catalyzed Ignition of Bipropellants in Microtubes

NASA Technical Reports Server (NTRS)

Schneider, Steven J.; Boyarko, George A.; Sung, Chih-Jen

2003-01-01

This paper addresses the need to understand the physics and chemistry involved in propellant combustion processes in micro-scale combustors for propulsion systems on micro-spacecraft. These spacecraft are planned to have a mass less than 50 kilograms with attitude control estimated to be in the 10 milli-Newton thrust class. These combustors are anticipated to be manufactured using Micro Electrical Mechanical Systems (MEMS) technology and are expected to have diameters approaching the quenching diameter of the propellants. Combustors of this size are expected to benefit significantly from surface catalysis processes. Miniature flame tube apparatus is chosen for this study because microtubes can be easily fabricated from known catalyst materials and their simplicity in geometry can be used in fundamental simulations to more carefully characterize the measured heat transfer and pressure losses for validation purposes. Experimentally, we investigate the role of catalytically active surfaces within 0.4 and 0.8 mm internal diameter micro-tubes, with special emphases on ignition and extinction processes in fuel rich gaseous hydrogen and gaseous oxygen. Flame thickness and reaction zone thickness calculations predict that the diameters of our test apparatus are below the quenching diameter of the propellants in sub-atmospheric tests. Temperature and pressure rises in resistively heated platinum and palladium micro-tubes are used as an indication of exothermic reactions. Specific data on mass flow versus preheat temperature required to achieve ignition are presented.

Heat generated during seating of dental implant fixtures.

PubMed

Flanagan, Dennis

2014-04-01

Frictional heat can be generated during seating of dental implants into a drill-prepared osteotomy. This in vitro study tested the heat generated by implant seating in dense bovine mandible ramus. A thermocouple was placed approximately 0.5 mm from the rim of the osteotomy during seating of each dental implant. Four diameters of implants were tested. The average temperature increases were 0.075°C for the 5.7-mm-diameter implant, 0.97°C for the 4.7-mm-diameter implant, 1.4°C for the 3.7-mm-diameter implant, and 8.6°C for the 2.5-mm-diameter implant. The results showed that heat was indeed generated and a small temperature rise occurred, apparently by the friction of the implant surface against the fresh-cut bone surface. Bone is a poor thermal conductor. The titanium of the implant and the steel of the handpiece are much better heat conductors. Titanium may be 70 times more heat conductive than bone. The larger diameter and displacement implant may act as a heat sink to draw away any heat produced from the friction of seating the implant at the bone-implant interface. The peak temperature duration was momentary, and not measured, but this was approximately less than 1 second. Except for the 2.5-mm-diameter implants, the temperature rises and durations were found to be below those previously deemed to be detrimental, so no clinically significant osseous damage would be expected during dental implant fixture seating of standard and large-diameter-sized implants. A 2.5-mm implant may generate detrimental heat during seating in nonvital bone, but this may be clinically insignificant in vital bone. The surface area and thermal conductivity are important factors in removing generated heat transfer at the bone-implant interface. The F value as determined by analysis of variance was 69.22, and the P value was less than .0001, demonstrating significant differences between the groups considered as a whole.

Climate impacts on agriculture: Implications for forage and rangeland production

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

Izaurralde, Roberto C.; Thomson, Allison M.; Morgan, Jack

2011-04-19

Projections of temperature and precipitation patterns across the United States during the next 50 years anticipate a 1.5 to 2°C warming and a slight increase in precipitation as a result of global climate change. There have been relatively few studies of climate change impacts on pasture and rangeland (grazingland) species compared to those on crop species, despite the economic and ecological importance of the former. Here we review the literature on pastureland and rangeland species to rising CO2 and climate change (temperature, and precipitation) and discuss plant and management factors likely to influence pastureland and rangeland responses to change (e.g.,more » community composition, plant competition, perennial growth habit, seasonal productivity, and management methods). Overall, the response of pasture species to increased [CO2] is consistent with the general response of C3 and C4 type vegetation, although significant exceptions exist. Both pastureland and rangeland species should exhibit an acceleration of metabolism and development due to earlier onset of spring green-up and longer growing seasons. However, in the studies reviewed here, C3 pasture species increased their photosynthetic rates by up to 40% while C4 species exhibited no increase in photosynthesis. In general, it is expected that increases in [CO2] and precipitation would enhance rangeland net primary production (NPP) while increased air temperatures would either increase or decrease NPP. Much of this uncertainty in response is due to uncertain future projections of precipitation, both globally and regionally. For example, if annual precipitation changes little or declines, rangeland plant response to warming temperatures and rising [CO2] may be neutral or may decline due to increased water stress. This review reveals the need for comprehensive studies of climate change impacts on the pasture ecosystem including grazing regimes, mutualistic relationships (e.g., plant roots-nematodes; N-fixing organisms), as well as the ecosystem carbon balance, essential nutrients, and water.« less

40 CFR 411.22 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. English units (lb/1,000 lb of dust leached) TSS 0.4. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. [39 FR 6591, Feb. 20, 1974, as amended at 60 FR 33951, June 29...

40 CFR 411.22 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. English units (lb/1,000 lb of dust leached) TSS 0.4. Temperature (heat) Not to exceed 3 °C rise above inlet temperature. pH Within the range 6.0 to 9.0. [39 FR 6591, Feb. 20, 1974, as amended at 60 FR 33951, June 29...

Heat profiling of phacoemulsification tip using a thermal scanning camera.

PubMed

Ngo, Wei Kiong; Lim, Louis W; Tan, Colin S H; Heng, Wee Jin

2013-12-01

An experimental study to measure the heat profile of the phacoemulsification (phaco) tip using standard continuous phaco and hyperpulse phaco with and without waveform power modulation in the Millennium Microsurgical System with Custom Control Software (CCS). The phaco tip was imaged in air using a thermal camera. The highest temperature was measured 15 s after application of phaco power. Continuous, hyperpulse and waveform power modulations of the Millennium Microsurgical System were used with different power settings (20, 50 and 100 %) and duty cycles (40, 60 and 90 %), with the irrigation turned on and off. Using continuous phaco with the irrigation on, the phaco tip temperature remains <28.0 °C. With irrigation off, the temperature is higher compared to irrigation on but still remains <45.0 °C. Comparing the temperatures for all three power modulations when irrigation is on, at each phaco power and duty cycle setting, the temperature of the phaco tip is highest with continuous phaco, followed by hyperpulse with rise time 1, then hyperpulse with rise time 2. When irrigation is off, the highest temperatures are recorded using the hyperpulse with rise time 2, followed by continuous phaco, then hyperpulse with rise time 1. Hyperpulse and waveform modulations reduce heat generation compared to the continuous mode when irrigation is turned on. Lower duty cycles and lower ultrasound power produce less heat at the phaco tip.

Assessment of Temperature Rise and Time of Alveolar Ridge Splitting by Means of Er:YAG Laser, Piezosurgery, and Surgical Saw: An Ex Vivo Study

PubMed Central

Flieger, Rafał; Dominiak, Marzena

2016-01-01

The most common adverse effect after bone cutting is a thermal damage. The aim of our study was to evaluate the bone temperature rise during an alveolar ridge splitting, rating the time needed to perform this procedure and the time to raise the temperature of a bone by 10°C, as well as to evaluate the bone carbonization occurrence. The research included 60 mandibles (n = 60) of adult pigs, divided into 4 groups (n = 15). Two vertical and one horizontal cut have been done in an alveolar ridge using Er:YAG laser with set power of 200 mJ (G1), 400 mJ (G2), piezosurgery unit (G3), and a saw (G4). The temperature was measured by K-type thermocouple. The highest temperature gradient was noted for piezosurgery on the buccal and lingual side of mandible. The temperature rises on the bone surface along with the increase of laser power. The lower time needed to perform ridge splitting was measured for a saw, piezosurgery, and Er:YAG laser with power of 400 mJ and 200 mJ, respectively. The temperature rise measured on the bone over 10°C and bone carbonization occurrence was not reported in all study groups. Piezosurgery, Er:YAG laser (200 mJ and 400 mJ), and surgical saw are useful and safe tools in ridge splitting surgery. PMID:27957502

Assessment of Temperature Rise and Time of Alveolar Ridge Splitting by Means of Er:YAG Laser, Piezosurgery, and Surgical Saw: An Ex Vivo Study.

PubMed

Matys, Jacek; Flieger, Rafał; Dominiak, Marzena

2016-01-01

The most common adverse effect after bone cutting is a thermal damage. The aim of our study was to evaluate the bone temperature rise during an alveolar ridge splitting, rating the time needed to perform this procedure and the time to raise the temperature of a bone by 10°C, as well as to evaluate the bone carbonization occurrence. The research included 60 mandibles ( n = 60) of adult pigs, divided into 4 groups ( n = 15). Two vertical and one horizontal cut have been done in an alveolar ridge using Er:YAG laser with set power of 200 mJ (G1), 400 mJ (G2), piezosurgery unit (G3), and a saw (G4). The temperature was measured by K-type thermocouple. The highest temperature gradient was noted for piezosurgery on the buccal and lingual side of mandible. The temperature rises on the bone surface along with the increase of laser power. The lower time needed to perform ridge splitting was measured for a saw, piezosurgery, and Er:YAG laser with power of 400 mJ and 200 mJ, respectively. The temperature rise measured on the bone over 10°C and bone carbonization occurrence was not reported in all study groups. Piezosurgery, Er:YAG laser (200 mJ and 400 mJ), and surgical saw are useful and safe tools in ridge splitting surgery.

Using time lapse cameras to monitor shoreline changes due to sea level rise.

DOT National Transportation Integrated Search

2017-01-01

Shoreline habitats and infrastructure are currently being affected by sea level rise (SLR) and as : global temperatures continue to rise, will continue to get worse for millennia. Governments : and individuals decisions to adapt to SLR could ha...

Temperature rise during removal of fractured components out of the implant body: an in vitro study comparing two ultrasonic devices and five implant types.

PubMed

Meisberger, Eric W; Bakker, Sjoerd J G; Cune, Marco S

2015-12-01

Ultrasonic instrumentation under magnification may facilitate mobilization of screw remnants but may induce heat trauma to surrounding bone. An increase of 5°C is considered detrimental to osseointegration. The objective of this investigation was to examine the rise in temperature of the outer implant body after 30 s of ultrasonic instrumentation to the inner part, in relation to implant type, type of ultrasonic equipment, and the use of coolants in vitro. Two ultrasonic devices (Satelec Suprasson T Max and Electro Medical Systems (EMS) miniMaster) were used on five different implant types that were provided with a thermo couple (Astra 3.5 mm, bone level Regular CrossFit (RC) 4.1 mm, bone level Narrow CrossFit (NC) 3.3 mm, Straumann tissue level regular body regular neck 3.3 mm, and Straumann tissue level wide body regular neck 4.8 mm), either with or without cooling during 30 s. Temperature rise at this point in time is the primary outcome measure. In addition, the mean maximum rise in temperature (all implants combined) was assessed and statistically compared among devices, implant systems, and cooling mode (independent t-tests, ANOVA, and post hoc analysis). The Satelec device without cooling induces the highest temperature change of up to 13°C, particularly in both bone level implants (p < 0.05) but appears safe for approximately 10 s of continuous instrumentation, after which a cooling down period is rational. Cooling is effective for both devices. However, when the Satelec device is used with coolant for a longer period of time, a rise in temperature must be anticipated after cessation of instrumentation, and post-operational cooling is advised. The in vitro setup used in this experiment implies that care should be taken when translating the observations to clinical recommendations, but it is carefully suggested that the EMS device causes limited rise in temperature, even without coolant.

Effect of temperature on heavy metal toxicity to juvenile crayfish, Orconectes immunis (Hagen).

PubMed

Khan, M A Q; Ahmed, S A; Catalin, Bogdon; Khodadoust, A; Ajayi, Oluwaleke; Vaughn, Mark

2006-10-01

The acute toxicity of four selected heavy metals to juvenile crayfish Orconectes immunis (Hagen) (1-2 g wet body wt. each) at room temperature increased in the following order: cadmium (x3) < copper (x10) < zinc (x2) < lead. The toxicity of these metals to crayfish acclimated at 17, 20, 23/24, and 27 degrees C increased with temperature (by 7-20% between 20 and 24 degrees C and 14-26% between 20 and 27 degrees C) as judged by the lowering of LT(50) (time to kill 50% of test animals at a fixed concentration) values. A 4 degrees C rise in temperature (from 20 to 24 degrees C), which increased the toxicity of copper by about 7%, increased the rate of oxygen consumption by about 34%. Heavy metals inhibited the rate of oxygen consumption at all temperatures. In 20 degrees C-acclimated crayfish, copper caused about 17% inhibition of oxygen consumption compared to about 7-12% by other metals including the most toxic cadmium. A 3-4 degrees C rise in temperature tripled the inhibitory effect of copper (20%), cadmium and zinc (26 and 18%, respectively), but not of lead, on oxygen consumption. A 7 degrees C-rise in temperature (from 20 to 27 degrees C) increased the inhibitory effect of heavy metals, including lead, on oxygen consumption by up to 54% in the case of copper. The data indicate that rising global temperatures (currently 0.60 degrees C) associated with climate change can have the potential to increase the sensitivity of aquatic animals to heavy metals in their environment.

Room-temperature magnetic topological Weyl fermion and nodal line semimetal states in half-metallic Heusler Co 2TiX (X=Si, Ge, or Sn)

DOE PAGES

Chang, Guoqing; Xu, Su -Yang; Zheng, Hao; ...

2016-12-15

Topological semimetals (TSMs) including Weyl semimetals and nodal-line semimetals are expected to open the next frontier of condensed matter and materials science. Although the first inversion breaking Weyl semimetal was recently discovered in TaAs, its magnetic counterparts, i.e., the time-reversal breaking Weyl and nodal line semimetals, remain elusive. They are predicted to exhibit exotic properties distinct from the inversion breaking TSMs including TaAs. In this paper, we identify the magnetic topological semimetal states in the ferromagnetic half-metal compounds Co 2TiX (X = Si, Ge, or Sn) with Curie temperatures higher than 350 K. Our first-principles band structure calculations show that,more » in the absence of spin-orbit coupling, Co 2TiX features three topological nodal lines. The inclusion of spin-orbit coupling gives rise to Weyl nodes, whose momentum space locations can be controlled as a function of the magnetization direction. Lastly, our results not only open the door for the experimental realization of topological semimetal states in magnetic materials at room temperature, but also suggest potential applications such as unusual anomalous Hall effect in engineered monolayers of the Co 2TiX compounds at high temperature.« less

Influence of predicted climage change elements on Z. ...

EPA Pesticide Factsheets

Global climate change (GCC) is expected to have pronounced impacts on estuarine and marine habitats including sea level rise, increased storm intensity, increased air and water temperatures, changes in upwelling dynamics and ocean acidification. All of these elements are likely to impact the growth and potential distribution of the non-indigenous seagrass Zostera japonica both within the State of Washington and within the region. Understanding how Z. japonica will respond to GCC requires a thorough understanding of plant physiology and predictions of GCC effects. Furthermore, Washington State is proposing to list Z. japonica as a “noxious weed” which will allow the state to use herbicide controls for management. We present data from manipulative experiments designed to better understand how Z. japonica photosynthetic physiology responds to temperature, salinity and light. We found that Z. japonica is well adapted to moderate temperatures and salinity with maximum photosynthesis of salinity of 20. The Coos Bay population had greater Pmax and saturation irradiance (Ik) than the Padilla bay population (p < 0.001) and tolerates daily exposure to both freshwater and marine water, suggesting that this population tolerates fairly extreme environmental fluctuations. Extreme temperatures (35 °C) were generally lethal to Z. japonica populations from Padilla, Coos and Yaquina Bays. High salinity (35) had lower mortality than either salinity of 5 or 20 (p = 0.0

Development of Predictive Models for the Growth Kinetics of Listeria monocytogenes on Fresh Pork under Different Storage Temperatures.

PubMed

Luo, Ke; Hong, Sung-Sam; Wang, Jun; Chung, Mi-Ja; Deog-Hwan, Oh

2015-05-01

This study was conducted to develop a predictive model to estimate the growth of Listeria monocytogenes on fresh pork during storage at constant temperatures (5, 10, 15, 20, 25, 30, and 35°C). The Baranyi model was fitted to growth data (log CFU per gram) to calculate the specific growth rate (SGR) and lag time (LT) with a high coefficient of determination (R(2) > 0.98). As expected, SGR increased with a decline in LT with rising temperatures in all samples. Secondary models were then developed to describe the variation of SGR and LT as a function of temperature. Subsequently, the developed models were validated with additional independent growth data collected at 7, 17, 27, and 37°C and from published reports using proportion of relative errors and proportion of standard error of prediction. The proportion of relative errors of the SGR and LT models developed herein were 0.79 and 0.18, respectively. In addition, the standard error of prediction values of the SGR and LT of L. monocytogenes ranged from 25.7 to 33.1% and from 44.92 to 58.44%, respectively. These results suggest that the model developed in this study was capable of predicting the growth of L. monocytogenes under various isothermal conditions.

Room-temperature magnetic topological Weyl fermion and nodal line semimetal states in half-metallic Heusler Co 2TiX (X=Si, Ge, or Sn)

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

Chang, Guoqing; Xu, Su -Yang; Zheng, Hao

Topological semimetals (TSMs) including Weyl semimetals and nodal-line semimetals are expected to open the next frontier of condensed matter and materials science. Although the first inversion breaking Weyl semimetal was recently discovered in TaAs, its magnetic counterparts, i.e., the time-reversal breaking Weyl and nodal line semimetals, remain elusive. They are predicted to exhibit exotic properties distinct from the inversion breaking TSMs including TaAs. In this paper, we identify the magnetic topological semimetal states in the ferromagnetic half-metal compounds Co 2TiX (X = Si, Ge, or Sn) with Curie temperatures higher than 350 K. Our first-principles band structure calculations show that,more » in the absence of spin-orbit coupling, Co 2TiX features three topological nodal lines. The inclusion of spin-orbit coupling gives rise to Weyl nodes, whose momentum space locations can be controlled as a function of the magnetization direction. Lastly, our results not only open the door for the experimental realization of topological semimetal states in magnetic materials at room temperature, but also suggest potential applications such as unusual anomalous Hall effect in engineered monolayers of the Co 2TiX compounds at high temperature.« less

Modeling of steady-state convective cooling of cylindrical Li-ion cells

NASA Astrophysics Data System (ADS)

Shah, K.; Drake, S. J.; Wetz, D. A.; Ostanek, J. K.; Miller, S. P.; Heinzel, J. M.; Jain, A.

2014-07-01

While Lithium-ion batteries have the potential to serve as an excellent means of energy storage, they suffer from several operational safety concerns. Temperature excursion beyond a specified limit for a Lithium-ion battery triggers a sequence of decomposition and release, which can preclude thermal runaway events and catastrophic failure. To optimize liquid or air-based convective cooling approaches, it is important to accurately model the thermal response of Lithium-ion cells to convective cooling, particularly in high-rate discharge applications where significant heat generation is expected. This paper presents closed-form analytical solutions for the steady-state temperature profile in a convectively cooled cylindrical Lithium-ion cell. These models account for the strongly anisotropic thermal conductivity of cylindrical Lithium-ion batteries due to the spirally wound electrode assembly. Model results are in excellent agreement with experimentally measured temperature rise in a thermal test cell. Results indicate that improvements in radial thermal conductivity and axial convective heat transfer coefficient may result in significant peak temperature reduction. Battery sizing optimization using the analytical model is discussed, indicating the dependence of thermal performance of the cell on its size and aspect ratio. Results presented in this paper may aid in accurate thermal design and thermal management of Lithium-ion batteries.

The Mobile Worker in the Flexible Workplace. Trends and Issues Alert No. 10.

ERIC Educational Resources Information Center

Brown, Bettina Lankard

New information technologies, changing work force demographics, rising customer expectations, transnational companies, and cost pressures are altering traditional views of what constitutes a workplace and have given rise to a new trend: the mobile worker in the flexible workplace. Two factors promote acceptance of telework or telecommuting: (1)…

Increasing Student Engagement with Practical Classes through Online Pre-Lab Quizzes

ERIC Educational Resources Information Center

Cann, Alan J.

2016-01-01

Laboratory practicals classes are an essential component of all science degrees, but are a pinch point because of rising student numbers, rising student expectations and falling student exposure to laboratory work prior to entering higher education. Augmentation of physical laboratory work with online interventions is not new, but as virtual…

Computational modelling of temperature rises in the eye in the near field of radiofrequency sources at 380, 900 and 1800 MHz

NASA Astrophysics Data System (ADS)

Wainwright, P. R.

2007-07-01

This paper reports calculations of the temperature rises induced in the eye and lens by near-field exposure to radiation from communication handsets, using the finite difference time domain method and classical bioheat equation. Various models are compared, including the analytic solution for a sphere, a finite element model of an isolated eye and a modern model of the whole head. The role of the blood supply to the choroid in moderating temperature is discussed. Three different frequencies are considered, namely 380 MHz (used by TETRA), and 900 and 1800 MHz (used by GSM mobile phones). At 380 MHz, monopole and helical antennas are compared. An 'equivalent blood flow' is derived for the choroid in order to facilitate comparison of the whole head and isolated eye models. In the whole head model, the heating of the lens receives a significant contribution from energy absorbed outside the eye. The temperature rise in the lens is compared to the ICNIRP-recommended average specific energy absorption rate (SAR) and the SAR averaged over the eye alone. The temperature rise may reach 1.4 °C at the ICNIRP occupational exposure limit if an antenna is placed less than 24 mm from the eye and the exposure is sufficiently prolonged.

Computational modelling of temperature rises in the eye in the near field of radiofrequency sources at 380, 900 and 1800 MHz.

PubMed

Wainwright, P R

2007-06-21

This paper reports calculations of the temperature rises induced in the eye and lens by near-field exposure to radiation from communication handsets, using the finite difference time domain method and classical bioheat equation. Various models are compared, including the analytic solution for a sphere, a finite element model of an isolated eye and a modern model of the whole head. The role of the blood supply to the choroid in moderating temperature is discussed. Three different frequencies are considered, namely 380 MHz (used by TETRA), and 900 and 1800 MHz (used by GSM mobile phones). At 380 MHz, monopole and helical antennas are compared. An 'equivalent blood flow' is derived for the choroid in order to facilitate comparison of the whole head and isolated eye models. In the whole head model, the heating of the lens receives a significant contribution from energy absorbed outside the eye. The temperature rise in the lens is compared to the ICNIRP-recommended average specific energy absorption rate (SAR) and the SAR averaged over the eye alone. The temperature rise may reach 1.4 degrees C at the ICNIRP occupational exposure limit if an antenna is placed less than 24 mm from the eye and the exposure is sufficiently prolonged.

Communicating the deadly consequences of global warming for human heat stress

PubMed Central

Matthews, Tom K. R.; Wilby, Robert L.; Murphy, Conor

2017-01-01

In December of 2015, the international community pledged to limit global warming to below 2 °C above preindustrial (PI) to prevent dangerous climate change. However, to what extent, and for whom, is danger avoided if this ambitious target is realized? We address these questions by scrutinizing heat stress, because the frequency of extremely hot weather is expected to continue to rise in the approach to the 2 °C limit. We use analogs and the extreme South Asian heat of 2015 as a focusing event to help interpret the increasing frequency of deadly heat under specified amounts of global warming. Using a large ensemble of climate models, our results confirm that global mean air temperature is nonlinearly related to heat stress, meaning that the same future warming as realized to date could trigger larger increases in societal impacts than historically experienced. This nonlinearity is higher for heat stress metrics that integrate the effect of rising humidity. We show that, even in a climate held to 2 °C above PI, Karachi (Pakistan) and Kolkata (India) could expect conditions equivalent to their deadly 2015 heatwaves every year. With only 1.5 °C of global warming, twice as many megacities (such as Lagos, Nigeria, and Shanghai, China) could become heat stressed, exposing more than 350 million more people to deadly heat by 2050 under a midrange population growth scenario. The results underscore that, even if the Paris targets are realized, there could still be a significant adaptation imperative for vulnerable urban populations. PMID:28348220

Temperature responses to infusion of electrolytes during exercise

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Kozlowski, S.; Kaciuba-Uscilko, H.; Nazar, K.; Brzezinska, Z.

1975-01-01

To gain more insight into the ion-osmotic influence on temperature regulation, the rectal temperature responses of mongrel dogs were measured during one hour of treadmill-running at 1.2 m/sec up a 12 deg slope. Results indicate that as in man, the rise in body temperature during exercise appears to be a regulated process. There is a direct relationship between the rise and equilibrium levels of rectal temperature and the plasma sodium and osmotic concentrations. It remains to be determined if the hypernatremic-osmolality inhibits peripheral blood flow, the panting, salivation response, or both. Some background on previous experiments on resting and exercising dogs and men is recounted.

Influence of geographic setting on thermal discharge from coastal power plants.

PubMed

Jia, Hou-Lei; Zheng, Shu; Xie, Jian; Ying, Xiao-Ming; Zhang, Cui-Ping

2016-10-15

Characteristics of thermal discharge from three coastal power plants were studied in China. The three plants, Zhuhai Power Plant, Chaozhou Power Plant and Huilai Power Plant, are located in estuary, bay and open sea, respectively. The water temperatures and ocean currents surrounding the outlet of the three power plants were monitored. The results show that the temperature rise became smaller as the spread of thermal discharge moved toward the open sea, which confirms the results of previous studies. The results also indicated that the influence range of thermal discharge from a coastal power plant is determined by geographic setting. The temperature rise range of the Chaozhou Plant, which is located in a bay, was the largest, followed by that of the Zhuhai Plant located in an estuary, and the temperature rise range of the Huilai Plant located in an open sea was the smallest. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physics responsible for heating efficiency and self-controlled temperature rise of magnetic nanoparticles in magnetic hyperthermia therapy.

PubMed

Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

2018-03-01

Magnetic nanoparticles as heat-generating nanosources in hyperthermia treatment are still faced with many drawbacks for achieving sufficient clinical potential. In this context, increase in heating ability of magnetic nanoparticles in a biologically safe alternating magnetic field and also approach to a precise control on temperature rise are two challenging subjects so that a significant part of researchers' efforts has been devoted to them. Since a deep understanding of Physics concepts of heat generation by magnetic nanoparticles is essential to develop hyperthermia as a cancer treatment with non-adverse side effects, this review focuses on different mechanisms responsible for heat dissipation in a radio frequency magnetic field. Moreover, particular attention is given to ferrite-based nanoparticles because of their suitability in radio frequency magnetic fields. Also, the key role of Curie temperature in suppressing undesired temperature rise is highlighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

The impact of rising sea temperature on innate immune parameters in the tropical subtidal sea urchin Lytechinus variegatus and the intertidal sea urchin Echinometra lucunter.

PubMed

Branco, Paola Cristina; Borges, João Carlos Shimada; Santos, Marinilce Fagundes; Jensch Junior, Bernard Ernesto; da Silva, José Roberto Machado Cunha

2013-12-01

Ocean temperatures are rising throughout the world, making it necessary to evaluate the impact of these temperature changes on sea urchins, which are well-known bioindicators. This study evaluated the effect of an increase in temperature on the immune response of the subtidal Lytechinus variegatus and the intertidal Echinometra lucunter sea urchins. Both species were exposed to 20 (control), 25 and 30 °C temperatures for 24 h, 2, 7 and 14 days. Counting of coelomocytes and assays on the phagocytic response, adhesion and spreading of coelomocytes were performed. Red and colorless sphere cells were considered biomarkers for heat stress. Moreover, a significant decrease in the phagocytic indices and a decrease in both cell adhesion and cell spreading were observed at 25 and 30 °C for L. variegatus. For E. lucunter, the only alteration observed was for the cell proportions. This report shows how different species of sea urchins respond immunologically to rising temperatures. Copyright © 2013 Elsevier Ltd. All rights reserved.

Heat suppression of the fiber coating on a cladding light stripper in high-power fiber laser.

PubMed

Yan, Ming-Jian; Wang, Zheng; Meng, Ling-Qiang; Yin, Lu; Han, Zhi-Gang; Shen, Hua; Wang, Hai-Lin; Zhu, Ri-Hong

2018-01-20

We present a theoretical model for the thermal effect of the fiber coating on a high-power cladding light stripper, which is fabricated by chemical etching. For the input and output of the fiber coating, a novel segmented corrosion method and increasing attenuation method are proposed for heat suppression, respectively. The relationship between the attenuation and temperature rise of the fiber coating at the output is experimentally demonstrated. The temperature distribution of the fiber coating at the input as well as the return light power caused by scattering are measured for the etched fiber with different surface roughness values. The results suggest that the rise in temperature is primarily caused by the scattering light propagating into the coating. Finally, an attenuation of 27 dB is achieved. At a room temperature of 23°C and input pump power of 438 W, the highest temperature of the input fiber coating decreases from 39.5°C to 27.9°C by segmented corrosion, and the temperature rise of the output fiber coating is close to 0.

Heat and immunity: an experimental heat wave alters immune functions in three-spined sticklebacks (Gasterosteus aculeatus).

PubMed

Dittmar, Janine; Janssen, Hannah; Kuske, Andra; Kurtz, Joachim; Scharsack, Jörn P

2014-07-01

Global climate change is predicted to lead to increased temperatures and more extreme climatic events. This may influence host-parasite interactions, immunity and therefore the impact of infectious diseases on ecosystems. However, little is known about the effects of rising temperatures on immune defence, in particular in ectothermic animals, where the immune system is directly exposed to external temperature change. Fish are ideal models for studying the effect of temperature on immunity, because they are poikilothermic, but possess a complete vertebrate immune system with both innate and adaptive immunity. We used three-spined sticklebacks ( Gasterosteus aculeatus) originating from a stream and a pond, whereby the latter supposedly were adapted to higher temperature variation. We studied the effect of increasing and decreasing temperatures and a simulated heat wave with subsequent recovery on body condition and immune parameters. We hypothesized that the immune system might be less active at low temperatures, but will be even more suppressed at temperatures towards the upper tolerable temperature range. Contrary to our expectation, we found innate and adaptive immune activity to be highest at a temperature as low as 13 °C. Exposure to a simulated heat wave induced long-lasting immune disorders, in particular in a stickleback population that might be less adapted to temperature variation in its natural environment. The results show that the activity of the immune system of an ectothermic animal species is temperature dependent and suggest that heat waves associated with global warming may immunocompromise host species, thereby potentially facilitating the spread of infectious diseases. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Warming will affect phytoplankton differently: evidence through a mechanistic approach

PubMed Central

Huertas, I. Emma; Rouco, Mónica; López-Rodas, Victoria; Costas, Eduardo

2011-01-01

Although the consequences of global warming in aquatic ecosystems are only beginning to be revealed, a key to forecasting the impact on aquatic communities is an understanding of individual species' vulnerability to increased temperature. Despite their microscopic size, phytoplankton support about half of the global primary production, drive essential biogeochemical cycles and represent the basis of the aquatic food web. At present, it is known that phytoplankton are important targets and, consequently, harbingers of climate change in aquatic systems. Therefore, investigating the capacity of phytoplankton to adapt to the predicted warming has become a relevant issue. However, considering the polyphyletic complexity of the phytoplankton community, different responses to increased temperature are expected. We experimentally tested the effects of warming on 12 species of phytoplankton isolated from a variety of environments by using a mechanistic approach able to assess evolutionary adaptation (the so-called ratchet technique). We found different degrees of tolerance to temperature rises and an interspecific capacity for genetic adaptation. The thermal resistance level reached by each species is discussed in relation to their respective original habitats. Our study additionally provides evidence on the most resistant phytoplankton groups in a future warming scenario. PMID:21508031

Strong correlation effects in theoretical STM studies of magnetic adatoms

NASA Astrophysics Data System (ADS)

Dang, Hung T.; dos Santos Dias, Manuel; Liebsch, Ansgar; Lounis, Samir

2016-03-01

We present a theoretical study for the scanning tunneling microscopy (STM) spectra of surface-supported magnetic nanostructures, incorporating strong correlation effects. As concrete examples, we study Co and Mn adatoms on the Cu(111) surface, which are expected to represent the opposite limits of Kondo physics and local moment behavior, using a combination of density functional theory and both quantum Monte Carlo and exact diagonalization impurity solvers. We examine in detail the effects of temperature T , correlation strength U , and impurity d electron occupancy Nd on the local density of states. We also study the effective coherence energy scale, i.e., the Kondo temperature TK, which can be extracted from the STM spectra. Theoretical STM spectra are computed as a function of STM tip position relative to each adatom. Because of the multiorbital nature of the adatoms, the STM spectra are shown to consist of a complicated superposition of orbital contributions, with different orbital symmetries, self-energies, and Kondo temperatures. For a Mn adatom, which is close to half-filling, the STM spectra are featureless near the Fermi level. On the other hand, the quasiparticle peak for a Co adatom gives rise to strongly position-dependent Fano line shapes.

Hyperechogenicity during high intensity focused ultrasound (HIFU)

NASA Astrophysics Data System (ADS)

Crum, Lawrence; Bailey, Michael; Rabkin, Brian; Khokhlova, Vera; Vaezy, Shahram

2005-09-01

Ultrasound guidance of HIFU therapy is attractive because of its portability, low cost, real-time image processing, simple integration with HIFU instruments, and the extensive availability of diagnostic ultrasound; however, the use of ultrasound visualization for the guidance and monitoring of HIFU therapy often relies on the appearance of a hyperechoic region in the ultrasound image. It is often assumed that the formation of a hyperechoic region at the HIFU treatment site results from bubble activity generated during HIFU exposure. However, it has been determined that this region can be generated with relatively short bursts of HIFU (on the order of 30 ms), bursts so short that negligible temperature elevations are expected to occur. In examining the histology associated with these hyperechoes, there is little evidence of traditional cavitation damage; rather, it appears as if there are many bubbles generated within the individuals cells, suggesting a thermal mechanism. Thermocouple measurements of the temperature elevation were inaccurate due to the short insonation period, but showed only a few-degree temperature rise. These anomalous results will be presented, along with additional data on HIFU hyperechogenicity, and a hypothesis given for the phenomenological origins of this effect. [Work supported in part by the NSBRI, U.S. Army, and the NIH.

Warming will affect phytoplankton differently: evidence through a mechanistic approach.

PubMed

Huertas, I Emma; Rouco, Mónica; López-Rodas, Victoria; Costas, Eduardo

2011-12-07

Although the consequences of global warming in aquatic ecosystems are only beginning to be revealed, a key to forecasting the impact on aquatic communities is an understanding of individual species' vulnerability to increased temperature. Despite their microscopic size, phytoplankton support about half of the global primary production, drive essential biogeochemical cycles and represent the basis of the aquatic food web. At present, it is known that phytoplankton are important targets and, consequently, harbingers of climate change in aquatic systems. Therefore, investigating the capacity of phytoplankton to adapt to the predicted warming has become a relevant issue. However, considering the polyphyletic complexity of the phytoplankton community, different responses to increased temperature are expected. We experimentally tested the effects of warming on 12 species of phytoplankton isolated from a variety of environments by using a mechanistic approach able to assess evolutionary adaptation (the so-called ratchet technique). We found different degrees of tolerance to temperature rises and an interspecific capacity for genetic adaptation. The thermal resistance level reached by each species is discussed in relation to their respective original habitats. Our study additionally provides evidence on the most resistant phytoplankton groups in a future warming scenario.

Decadal-scale variation in diet forecasts persistently poor breeding under ocean warming in a tropical seabird

PubMed Central

Tompkins, Emily M.; Townsend, Howard M.

2017-01-01

Climate change effects on population dynamics of natural populations are well documented at higher latitudes, where relatively rapid warming illuminates cause-effect relationships, but not in the tropics and especially the marine tropics, where warming has been slow. Here we forecast the indirect effect of ocean warming on a top predator, Nazca boobies in the equatorial Galápagos Islands, where rising water temperature is expected to exceed the upper thermal tolerance of a key prey item in the future, severely reducing its availability within the boobies’ foraging envelope. From 1983 to 1997 boobies ate mostly sardines, a densely aggregated, highly nutritious food. From 1997 until the present, flying fish, a lower quality food, replaced sardines. Breeding success under the poor diet fell dramatically, causing the population growth rate to fall below 1, indicating a shrinking population. Population growth may not recover: rapid future warming is predicted around Galápagos, usually exceeding the upper lethal temperature and maximum spawning temperature of sardines within 100 years, displacing them permanently from the boobies’ island-constrained foraging range. This provides rare evidence of the effect of ocean warming on a tropical marine vertebrate. PMID:28832597

Decadal-scale variation in diet forecasts persistently poor breeding under ocean warming in a tropical seabird.

PubMed

Tompkins, Emily M; Townsend, Howard M; Anderson, David J

2017-01-01

Climate change effects on population dynamics of natural populations are well documented at higher latitudes, where relatively rapid warming illuminates cause-effect relationships, but not in the tropics and especially the marine tropics, where warming has been slow. Here we forecast the indirect effect of ocean warming on a top predator, Nazca boobies in the equatorial Galápagos Islands, where rising water temperature is expected to exceed the upper thermal tolerance of a key prey item in the future, severely reducing its availability within the boobies' foraging envelope. From 1983 to 1997 boobies ate mostly sardines, a densely aggregated, highly nutritious food. From 1997 until the present, flying fish, a lower quality food, replaced sardines. Breeding success under the poor diet fell dramatically, causing the population growth rate to fall below 1, indicating a shrinking population. Population growth may not recover: rapid future warming is predicted around Galápagos, usually exceeding the upper lethal temperature and maximum spawning temperature of sardines within 100 years, displacing them permanently from the boobies' island-constrained foraging range. This provides rare evidence of the effect of ocean warming on a tropical marine vertebrate.

Macroclimatic change expected to transform coastal wetland ecosystems this century

USGS Publications Warehouse

Gabler, Christopher A.; Osland, Michael J.; Grace, James B.; Stagg, Camille L.; Day, Richard H.; Hartley, Stephen B.; Enwright, Nicholas M.; From, Andrew; McCoy, Meagan L.; McLeod, Jennie L.

2017-01-01

Coastal wetlands, existing at the interface between land and sea, are highly vulnerable to climate change. Macroclimate (for example, temperature and precipitation regimes) greatly influences coastal wetland ecosystem structure and function. However, research on climate change impacts in coastal wetlands has concentrated primarily on sea-level rise and largely ignored macroclimatic drivers, despite their power to transform plant community structure and modify ecosystem goods and services. Here, we model wetland plant community structure based on macroclimate using field data collected across broad temperature and precipitation gradients along the northern Gulf of Mexico coast. Our analyses quantify strongly nonlinear temperature thresholds regulating the potential for marsh-to-mangrove conversion. We also identify precipitation thresholds for dominance by various functional groups, including succulent plants and unvegetated mudflats. Macroclimate-driven shifts in foundation plant species abundance will have large effects on certain ecosystem goods and services. Based on current and projected climatic conditions, we project that transformative ecological changes are probable throughout the region this century, even under conservative climate scenarios. Coastal wetland ecosystems are functionally similar worldwide, so changes in this region are indicative of potential future changes in climatically similar regions globally.

Contribution of air conditioning adoption to future energy use under global warming.

PubMed

Davis, Lucas W; Gertler, Paul J

2015-05-12

As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change.

Contribution of air conditioning adoption to future energy use under global warming

PubMed Central

Davis, Lucas W.; Gertler, Paul J.

2015-01-01

As household incomes rise around the world and global temperatures go up, the use of air conditioning is poised to increase dramatically. Air conditioning growth is expected to be particularly strong in middle-income countries, but direct empirical evidence is scarce. In this paper we use high-quality microdata from Mexico to describe the relationship between temperature, income, and air conditioning. We describe both how electricity consumption increases with temperature given current levels of air conditioning, and how climate and income drive air conditioning adoption decisions. We then combine these estimates with predicted end-of-century temperature changes to forecast future energy consumption. Under conservative assumptions about household income, our model predicts near-universal saturation of air conditioning in all warm areas within just a few decades. Temperature increases contribute to this surge in adoption, but income growth by itself explains most of the increase. What this will mean for electricity consumption and carbon dioxide emissions depends on the pace of technological change. Continued advances in energy efficiency or the development of new cooling technologies could reduce the energy consumption impacts. Similarly, growth in low-carbon electricity generation could mitigate the increases in carbon dioxide emissions. However, the paper illustrates the enormous potential impacts in this sector, highlighting the importance of future research on adaptation and underscoring the urgent need for global action on climate change. PMID:25918391

Gas chromatography using ice-coated fused silica columns: study of adsorption of sulfur dioxide on water ice

NASA Astrophysics Data System (ADS)

Langenberg, Stefan; Schurath, Ulrich

2018-05-01

The well established technique of gas chromatography is used to investigate interactions of sulfur dioxide with a crystalline ice film in a fused silica wide bore column. Peak shape analysis of SO2 chromatograms measured in the temperature range 205-265 K is applied to extract parameters describing a combination of three processes: (i) physisorption of SO2 at the surface, (ii) dissociative reaction with water and (iii) slow uptake into bulk ice. Process (ii) is described by a dissociative Langmuir isotherm. The pertinent monolayer saturation capacity is found to increase with temperature. The impact of process (iii) on SO2 peak retention time is found to be negligible under our experimental conditions. By analyzing binary chromatograms of hydrophobic n-hexane and hydrophilic acetone, the premelt surface layer is investigated in the temperature range 221-263 K, possibly giving rise to irregular adsorption. Both temperature dependencies fit simple van't Hoff equations as expected for process (i), implying that irregular adsorption of acetone is negligible in the investigated temperature range. Adsorption enthalpies of -45 ± 5 and -23±2 kJ mol-1 are obtained for acetone and n-hexane. The motivation of our study was to assess the vertical displacement of SO2 and acetone in the wake of aircraft by adsorption on ice particles and their subsequent sedimentation. Our results suggest that this transport mechanism is negligible.

Artefacts in intracavitary temperature measurements during regional hyperthermia.

PubMed

Kok, H P; Van den Berg, C A T; Van Haaren, P M A; Crezee, J

2007-09-07

For adequate hyperthermia treatments, reliable temperature information during treatment is essential. During regional hyperthermia, temperature information is preferably obtained non-invasively from intracavitary or intraluminal measurements to avoid implant risks for the patient. However, for intracavitary or intraluminal thermometry optimal tissue contact is less natural as for invasive thermometry. In this study, the reliability of intraluminal/intracavitary measurements was examined in phantom experiments and in a numerical model for various extents of thermal contact between thermometry and the surroundings. Both thermocouple probes and fibre optic probes were investigated. Temperature rises after a 30 s power pulse of the 70 MHz AMC-4 hyperthermia system were measured in a tissue-equivalent phantom using a multisensor thermocouple probe placed centrally in a hollow tube. The tube was filled with (1) air, (2) distilled water or (3) saline solution that mimics the properties of tissue, simulating situations with (1) bad thermal contact and no power dissipation in the tube, (2) good thermal contact but no power dissipation or (3) good thermal contact and tissue representative power dissipation. For numerical simulations, a cylindrical symmetric model of a thermocouple probe or a fibre optic probe in a cavity was developed. The cavity was modelled as air, distilled water or saline solution. A generalised E-Field distribution was assumed, resulting in a power deposition. With this power deposition, the temperature rise after a 30 s power pulse was calculated. When thermal contact was bad (1), both phantom measurements and simulations with a thermocouple probe showed very high temperature rises (>0.5 degrees C), which are artefacts due to self-heating of the thermocouple probe, since no power is dissipated in air. Simulations with a fibre optic probe showed almost no temperature rise when the cavity was filled with air. When thermal contact was good, but no power was dissipated in the tube (2), artefacts due to self-heating were not significant and the observed temperature rises were very low ( approximately 0-0.1 degrees C). For the situation, with tissue representative power dissipation (3), a temperature rise of approximately 0.23 degrees C was observed for both measurements and simulations. A clinical example of a regional hyperthermia treatment of a patient with a cervix uteri carcinoma showed that the artefacts observed in the case of bad thermal contact also affect the steady-state temperature measurements. Good tissue contact must be assured for reliable intraluminal or intracavitary measurements.

Nonlinear and Interactive Effects of Temperature and Humidity on Childhood Hand, Foot and Mouth Disease in Hefei, China.

PubMed

Wu, Jinju; Cheng, Jian; Xu, Zhiwei; Zhao, Kefu; Zhao, Desheng; Xie, Mingyu; Yang, Huihui; Wen, Liying; Li, Kesheng; Su, Hong

2016-10-01

Hand, foot and mouth disease (HFMD) is one of the major infectious diseases among children and remains a health threat, especially among Asian countries. Many epidemiologic studies suggested significant association of air temperature and humidity with childhood HFMD; however, evidence on the temperature effects on childhood HFMD in temperate cities is limited, and the interactive effects of temperature and humidity have not been studied yet. Daily counts of HFMD in children younger than 15 years of age and daily meteorologic variables during 2010 to 2012 were obtained in Hefei, China. A distributed lag nonlinear model was applied to estimate the potential nonlinear association between temperature and childhood HFMD. The interactive effects between temperature and humidity on childhood HFMD were also investigated. Temperature rise was associated with higher risk of childhood HFMD. Within the incubation period of HFMD, temperature rise appeared to have the acute effects on childhood HFMD, and a 5°C increase of temperature at lag 0-6 days was associated with 24.8% (95% confidence interval: 11.94%-39.10%) increase of childhood HFMD. Females and children of 0-4 years of agewere more vulnerable to temperature rise. Notably, there were obvious combined effects between temperature and humidity on childhood HFMD-the risk of childhood HFMD elevated at higher temperature and humidity level. This study provides evidence that temperature and humidity may jointly affect childhood HFMD, and such interactive impact needs to be considered when evaluating the temperature-childhood HFMD relationship.

Minimizing medical litigation, Part 1.

PubMed

Harold, Tan Keng Boon

2006-01-01

The global rise in medical litigation has led to defensive medical practices and rising malpractice insurance premiums. There is a need to review all possible factors influencing litigiousness of the society and to develop strategies to control such factors. Some of the contributory causes of rising litigiousness include higher patients' expectations, poor provider-patient communication, and adversarial legalism of the society. A good combination of system, professional, and legislative strategies may keep medical litigation in check. Part 2 of this article will address the development of a dispute resolution framework.

Non-Fourier thermal transport induced structural hierarchy and damage to collagen ultrastructure subjected to laser irradiation.

PubMed

Sahoo, Nilamani; Narasimhan, Arunn; Dhar, Purbarun; Das, Sarit K

2018-05-01

Comprehending the mechanism of thermal transport through biological tissues is an important factor for optimal ablation of cancerous tissues and minimising collateral tissue damage. The present study reports detailed mapping of the rise in internal temperature within the tissue mimics due to NIR (1064 nm) laser irradiation, both for bare mimics and with gold nanostructures infused. Gold nanostructures such as mesoflowers and nanospheres have been synthesised and used as photothermal converters to enhance the temperature rise, resulting in achieving the desired degradation of malignant tissue in targeted region. Thermal history was observed experimentally and simulated considering non-Fourier dual phase lag (DPL) model incorporated Pennes bio-heat transfer equation using COMSOL Multiphysics software. The gross deviation in temperature i.e. rise from the classical Fourier model for bio-heat conduction suggests additional effects of temperature rise on the secondary structures and morphological and physico-chemical changes to the collagen ultrastructures building the tissue mass. The observed thermal denaturation in the collagen fibril morphologies have been explained based on the physico-chemical structure of collagen and its response to thermal radiation. The large shift in frequency of amides A and B is pronounced at a depth of maximum temperature rise compared with other positions in tissue phantom. Observations for change in band of amide I, amide II, and amide III are found to be responsible for damage to collagen ultra-structure. Variation in the concentration of gold nanostructures shows the potentiality of localised hyperthermia treatment subjected to NIR radiation through a proposed free radical mechanism.

Effect of diode lasers with wavelength of 445 and 980 nm on a temperature rise when uncovering implants for second stage surgery: An ex-vivo study in pigs.

PubMed

Matys, Jacek; Flieger, Rafał; Dominiak, Marzena

2017-07-01

Many surgical procedures in soft tissue are performed using diode lasers. Recently, a novel diode laser operating at 445 nm wavelength was introduced in dentistry. The aim of our study was to evaluate the time of surgery and an increase in temperature of titanium implants during its uncovering using 445 and 980 nm wavelengths. The research included 45 pig mandibles (n = 45). The specimens were randomly divided into 3 groups (n = 15) according to the laser irradiation mode and wavelength; G1 - 445 nm laser, power: 3 W, continuous wave (CW), distance: 2 mm, power density: 7460 W/cm2, fiber: 320 μm, noncontact mode; G2 - 445 nm laser (power: 2 W, CW, power density: 4970 W/cm2, fiber: 320 μm, contact mode; G3 (control) - 980 nm laser, power: 2.5 W, CW, power density: 15920 W/cm2, fiber: 200 μm, contact mode. The temperature was measured with a 2 K-type thermocouples (a P1 at collar and a P2 at mid height of the implant). The mean temperature rises measured by the P1 thermocouple were 16.9°C, 36.1°C and 21.6°C in the G1, G2 and G3 group, respectively. Significant differences in temperature rise were found between the G1 and G2 group (p = 0.0007) and the G2 and G3 group (p = 0.01). The mean temperature rises measured by the P2 thermocouple were 1.8°C, 1.4°C and 5.6°C in the G1, G2 and G3 group, respectively. Significant differences in temperature rise were found between the G1 and the G2 or G3 group (p = 0.0001). The significant differences among the study groups in average time necessary for uncovering the implants amounted to 69.7, 54.4 and 83.6 s, respectively (p < 0.05). The application of the 445 nm diode laser in non-contact mode reduced the temperature rise of the implants. The additional pulse intervals during laser irradiation with wavelength of 445 nm when operating in contact mode are needed.

Coastal wetland adaptation to sea level rise: Quantifying potential for landward migration and coastal squeeze

USGS Publications Warehouse

Borchert, Sinéad M.; Osland, Michael J.; Enwright, Nicholas M.; Griffith, Kereen

2018-01-01

Coastal wetland ecosystems are expected to migrate landwards in response to rising seas. However, due to differences in topography and coastal urbanization, estuaries vary in their ability to accommodate migration. Low‐lying urban areas can constrain migration and lead to wetland loss (i.e. coastal squeeze), especially where existing wetlands cannot keep pace with rising seas via vertical adjustments. In many estuaries, there is a pressing need to identify landward migration corridors and better quantify the potential for landward migration and coastal squeeze.We quantified and compared the area available for landward migration of tidal saline wetlands and the area where urban development is expected to prevent migration for 39 estuaries along the wetland‐rich USA Gulf of Mexico coast. We did so under three sea level rise scenarios (0.5, 1.0, and 1.5 m by 2100).Within the region, the potential for wetland migration is highest within certain estuaries in Louisiana and southern Florida (e.g. Atchafalaya/Vermilion Bays, Mermentau River, Barataria Bay, and the North and South Ten Thousand Islands estuaries).The potential for coastal squeeze is highest in estuaries containing major metropolitan areas that extend into low‐lying lands. The Charlotte Harbor, Tampa Bay, and Crystal‐Pithlachascotee estuaries (Florida) have the highest amounts of urban land expected to constrain wetland migration. Urban barriers to migration are also high in the Galveston Bay (Texas) and Atchafalaya/Vermilion Bays (Louisiana) estuaries.Synthesis and applications. Coastal wetlands provide many ecosystem services that benefit human health and well‐being, including shoreline protection and fish and wildlife habitat. As the rate of sea level rise accelerates in response to climate change, coastal wetland resources could be lost in areas that lack space for landward migration. Migration corridors are particularly important in highly urbanized estuaries where, due to low‐lying coastal development, there is not space for wetlands to move and adapt to sea level rise. Future‐focused landscape conservation plans that incorporate the protection of wetland migration corridors can increase the adaptive capacity of these valuable ecosystems and simultaneously decrease the vulnerability of coastal human communities to the harmful effects of rising seas.

MRO's High Resolution Imaging Science Experiment (HiRISE): Polar Science Expectations

NASA Technical Reports Server (NTRS)

McEwen, A.; Herkenhoff, K.; Hansen, C.; Bridges, N.; Delamere, W. A.; Eliason, E.; Grant, J.; Gulick, V.; Keszthelyi, L.; Kirk, R.

2003-01-01

The Mars Reconnaissance Orbiter (MRO) is expected to launch in August 2005, arrive at Mars in March 2006, and begin the primary science phase in November 2006. MRO will carry a suite of remote-sensing instruments and is designed to routinely point off-nadir to precisely target locations on Mars for high-resolution observations. The mission will have a much higher data return than any previous planetary mission, with 34 Tbits of returned data expected in the first Mars year in the mapping orbit (255 x 320 km). The HiRISE camera features a 0.5 m telescope, 12 m focal length, and 14 CCDs. We expect to acquire approximately 10,000 observations in the primary science phase (approximately 1 Mars year), including approximately 2,000 images for 1,000 stereo targets. Each observation will be accompanied by a approximately 6 m/pixel image over a 30 x 45 km region acquired by MRO s context imager. Many HiRISE images will be full resolution in the center portion of the swath width and binned (typically 4x4) on the sides. This provides two levels of context, so we step out from 0.3 m/pixel to 1.2 m/pixel to 6 m/pixel (at 300 km altitude). We expect to cover approximately 1% of Mars at better than 1.2 m/pixel, approximately 0.1% at 0.3 m/pixel, approximately 0.1% in 3 colors, and approximately 0.05% in stereo. Our major challenge is to find the dey contacts, exposures and type morphologies to observe.

Can you hear the carbon rise? Evaluating multi-sensory climate media in undergraduate learning.

NASA Astrophysics Data System (ADS)

Twedt, J. R.; Frierson, D. M.; Pampin, J.; Bitz, C. M.

2017-12-01

Sound and music in climate outreach can help to reduce visual fatigue, aid people who are visually impaired, and create new neural pathways for thinking about and remembering climate science. Infosonics are the audio analogy to infographics, and are created through a process of data sonification whereby data is expressed as a sound rather than as a graphic. An example of our infosonics can be found on YouTube, titled "The Deafening Rise of Carbon Pollution." Because sound is heard moment to moment over time, the sonic representation of data is particularly well suited for time series. This allows the listener to hear each data point in sequence, one by one, rather than seeing it all at once. Infosonics can be made musical through the design process, expressing not only information in the data, but conveying affective content such as a sense of urgency, alarm, humor, or grief. We introduced climate infosonics in two large undergraduate courses where students are expected to become familiar with canonical climate datasets, including the Keeling Curve, Arctic sea ice extent, and the global mean surface temperature index. We present outcomes and lessons learned from using these infosonics in place of traditional visual graphics.

Spending our soil resources

USDA-ARS?s Scientific Manuscript database

A third of the world's population suffers from food insecurity. With an expected 2 billion population increase in the next few decades, that number is expected to rise significantly, leading to more people that are insecure and starving unless our soils can produce more food. Added to the problem ar...

Evidence that Tropical Forest Photosynthesis is Not Directly Limited by High Temperatures

NASA Astrophysics Data System (ADS)

Smith, M.; Taylor, T.; Van Haren, J. L. M.; Rosolem, R.; Restrepo-Coupe, N.; Wu, J.; Oliveira Junior, R. C.; Silva, R. D.; De Araujo, A. C.; Camargo, P. B. D.; Huxman, T. E.; Saleska, S. R.

2016-12-01

Loss of tropical forest biomass under rising temperatures could result in significant feedbacks to global climate. The vulnerability of tropical trees to climate warming depends on the specific physiological mechanisms controlling photosynthetic decline at temperatures above the thermal optimum. High temperatures may negatively impact photosynthetic metabolism (direct effects) (Doughty and Goulden 2008), or leaves may respond to the concomitant increase in vapor pressure deficit (VPD) by closing stomata (indirect effects) (Lloyd and Farquhar 2008). The difference is important because the former reveals a vulnerability of photosynthetic infrastructure to higher temperatures, while the latter is an expected physiological response of healthy leaves. We investigated these contrasting hypotheses in a climate controlled, 0.2 ha artificial tropical forest (the Biosphere 2 tropical forest biome, B2-TF). Typically coupled in nature, VPD and temperature can be varied independently in the controlled environment of the B2-TF, and their effects on photosynthesis distinguished. We found that in the B2-TF, gross ecosystem productivity (GEP) was strongly reduced by increasing VPD, but responded little to temperature. Whereas eddy flux-derived GEP of three natural tropical forest sites in the Amazon of Brazil declined at temperatures above 27°C, GEP in the B2-TF remained stable up to 33°C under both low and high VPD regimes. While either mechanism results in reduced photosynthesis, the impact of VPD is short-lived and may be mitigated by enhanced water use efficiency under elevated atmospheric CO2 concentrations, allowing tropical forests to be more resilient to climate warming.

Compartment-specific transcriptomics in a reef-building coral exposed to elevated temperatures.

PubMed

Mayfield, Anderson B; Wang, Yu-Bin; Chen, Chii-Shiarng; Lin, Chung-Yen; Chen, Shu-Hwa

2014-12-01

Although rising ocean temperatures threaten scleractinian corals and the reefs they construct, certain reef corals can acclimate to elevated temperatures to which they are rarely exposed in situ. Specimens of the model Indo-Pacific reef coral Pocillopora damicornis collected from upwelling reefs of Southern Taiwan were previously found to have survived a 36-week exposure to 30°C, a temperature they encounter infrequently and one that can elicit the breakdown of the coral-dinoflagellate (genus Symbiodinium) endosymbiosis in many corals of the Pacific Ocean. To gain insight into the subcellular pathways utilized by both the coral hosts and their mutualistic Symbiodinium populations to acclimate to this temperature, mRNAs from both control (27°C) and high (30°C)-temperature samples were sequenced on an Illumina platform and assembled into a 236 435-contig transcriptome. These P. damicornis specimens were found to be ~60% anthozoan and 40% microbe (Symbiodinium, other eukaryotic microbes, and bacteria), from an mRNA-perspective. Furthermore, a significantly higher proportion of genes from the Symbiodinium compartment were differentially expressed after two weeks of exposure. Specifically, at elevated temperatures, Symbiodinium populations residing within the coral gastrodermal tissues were more likely to up-regulate the expression of genes encoding proteins involved in metabolism than their coral hosts. Collectively, these transcriptome-scale data suggest that the two members of this endosymbiosis have distinct strategies for acclimating to elevated temperatures that are expected to characterize many of Earth's coral reefs in the coming decades. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Metabolic shifts in the Antarctic fish Notothenia rossii in response to rising temperature and PCO2

PubMed Central

2012-01-01

Introduction Ongoing ocean warming and acidification increasingly affect marine ecosystems, in particular around the Antarctic Peninsula. Yet little is known about the capability of Antarctic notothenioid fish to cope with rising temperature in acidifying seawater. While the whole animal level is expected to be more sensitive towards hypercapnia and temperature, the basis of thermal tolerance is set at the cellular level, with a putative key role for mitochondria. This study therefore investigates the physiological responses of the Antarctic Notothenia rossii after long-term acclimation to increased temperatures (7°C) and elevated PCO2 (0.2 kPa CO2) at different levels of physiological organisation. Results For an integrated picture, we analysed the acclimation capacities of N. rossii by measuring routine metabolic rate (RMR), mitochondrial capacities (state III respiration) as well as intra- and extracellular acid–base status during acute thermal challenges and after long-term acclimation to changing temperature and hypercapnia. RMR was partially compensated during warm- acclimation (decreased below the rate observed after acute warming), while elevated PCO2 had no effect on cold or warm acclimated RMR. Mitochondrial state III respiration was unaffected by temperature acclimation but depressed in cold and warm hypercapnia-acclimated fish. In both cold- and warm-exposed N. rossii, hypercapnia acclimation resulted in a shift of extracellular pH (pHe) towards more alkaline values. A similar overcompensation was visible in muscle intracellular pH (pHi). pHi in liver displayed a slight acidosis after warm normo- or hypercapnia acclimation, nevertheless, long-term exposure to higher PCO2 was compensated for by intracellular bicarbonate accumulation. Conclusion The partial warm compensation in whole animal metabolic rate indicates beginning limitations in tissue oxygen supply after warm-acclimation of N. rossii. Compensatory mechanisms of the reduced mitochondrial capacities under chronic hypercapnia may include a new metabolic equilibrium to meet the elevated energy demand for acid–base regulation. New set points of acid–base regulation under hypercapnia, visible at the systemic and intracellular level, indicate that N. rossii can at least in part acclimate to ocean warming and acidification. It remains open whether the reduced capacities of mitochondrial energy metabolism are adaptive or would impair population fitness over longer timescales under chronically elevated temperature and PCO2. PMID:23075125

Infrared thermal measurements of laser soft tissue ablation as a function of air/water coolant for Nd:YAG and diode lasers

NASA Astrophysics Data System (ADS)

Gekelman, Diana; Yamamoto, Andrew; Oto, Marvin G.; White, Joel M.

2003-06-01

The purpose of this investigation was to measure the maximum temperature at the Nd:YAG and Diode lasers fiberoptic tips as a function of air/water coolant, during soft tissue ablation in pig jaws. A pulsed Nd:YAG laser (1064nm) and a Diode laser (800-830 nm) were used varying parameters of power, conditioning or not of the fiber tip, under 4 settings of air/water coolant. The maximum temperature at the fiber tip was measured using an infra-red camera and the interaction of the fiber with the porcine soft tissue was evaluated. A two-factor ANOVA was used for statistical analysis (p<=0.05). Nd:YAG laser interaction with soft tissues produced temperatures levels directly proportional to power increase, but the conditioning of the fiber tip did not influence the temperature rise. On the other hand, conditioning of the fiber tip did influence the temperature rise for Diode laser. The addition of air/water coolant, for both lasers, did not promote temperature rise consistent with cutting and coagulation of porcine soft tissue. Laser parameters affect the fiberoptic surface temperature, and the addition of air/water coolant significantly lowered surface temperature on the fiberoptic tip for all lasers and parameters tested.

Ontogenetic Variation in the Thermal Biology of Yarrow's Spiny Lizard, Sceloporus jarrovii

PubMed Central

Gilbert, Anthony L.; Lattanzio, Matthew S.

2016-01-01

Climate change is rapidly altering the way current species interact with their environment to satisfy life-history demands. In areas anticipated to experience extreme warming, rising temperatures are expected to diminish population growth, due either to environmental degradation, or the inability to tolerate novel temperature regimes. Determining how at risk ectotherms, and lizards in particular, are to changes in climate traditionally emphasizes the thermal ecology and thermal sensitivity of physiology of adult members of a population. In this study, we reveal ontogenetic differences in thermal physiological and ecological traits that have been used to anticipate how ectotherms will respond to climate change. We show that the thermal biological traits of juvenile Yarrow’s Spiny Lizards (Sceloporus jarrovii) differ from the published estimates of the same traits for adult lizards. Juvenile S. jarrovii differ in their optimal performance temperature, field field-active body temperature, and critical thermal temperatures compared to adult S. jarrovii. Within juvenile S. jarrovii, males and females exhibit differences in field-active body temperature and desiccation tolerance. Given the observed age- and sex-related variation in thermal physiology, we argue that not including physiological differences in thermal biology throughout ontogeny may lead to misinterpretation of patterns of ecological or evolutionary change due to climate warming. Further characterizing the potential for ontogenetic changes in thermal biology would be useful for a more precise and accurate estimation of the role of thermal physiology in mediating population persistence in warmer environments. PMID:26840620

Deglacial temperature history of West Antarctica

USGS Publications Warehouse

Cuffey, Kurt M.; Clow, Gary D.; Steig, Eric J.; Buizert, Christo; Fudge, T.J.; Koutnik, Michelle; Waddington, Edwin D.; Alley, Richard B.; Severinghaus, Jeffrey P.

2016-01-01

The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth’s climate responds to various forcings, including a rise in atmospheric CO2. This transition has left a direct thermal remnant in the polar ice sheets, where the exceptional purity and continual accumulation of ice permit analyses not possible in other settings. For Antarctica, the deglacial warming has previously been constrained only by the water isotopic composition in ice cores, without an absolute thermometric assessment of the isotopes’ sensitivity to temperature. To overcome this limitation, we measured temperatures in a deep borehole and analyzed them together with ice-core data to reconstruct the surface temperature history of West Antarctica. The deglacial warming was 11.3±1.8∘">11.3±1.8∘11.3±1.8∘C, approximately two to three times the global average, in agreement with theoretical expectations for Antarctic amplification of planetary temperature changes. Consistent with evidence from glacier retreat in Southern Hemisphere mountain ranges, the Antarctic warming was mostly completed by 15 kyBP, several millennia earlier than in the Northern Hemisphere. These results constrain the role of variable oceanic heat transport between hemispheres during deglaciation and quantitatively bound the direct influence of global climate forcings on Antarctic temperature. Although climate models perform well on average in this context, some recent syntheses of deglacial climate history have underestimated Antarctic warming and the models with lowest sensitivity can be discounted.

Projected near-future levels of temperature and pCO2 reduce coral fertilization success.

PubMed

Albright, Rebecca; Mason, Benjamin

2013-01-01

Increases in atmospheric carbon dioxide (pCO2) are projected to contribute to a 1.1-6.4°C rise in global average surface temperatures and a 0.14-0.35 reduction in the average pH of the global surface ocean by 2100. If realized, these changes are expected to have negative consequences for reef-building corals including increased frequency and severity of coral bleaching and reduced rates of calcification and reef accretion. Much less is known regarding the independent and combined effects of temperature and pCO2 on critical early life history processes such as fertilization. Here we show that increases in temperature (+3°C) and pCO2 (+400 µatm) projected for this century negatively impact fertilization success of a common Indo-Pacific coral species, Acropora tenuis. While maximum fertilization did not differ among treatments, the sperm concentration required to obtain 50% of maximum fertilization increased 6- to 8- fold with the addition of a single factor (temperature or CO2) and nearly 50- fold when both factors interact. Our results indicate that near-future changes in temperature and pCO2 narrow the range of sperm concentrations that are capable of yielding high fertilization success in A. tenuis. Increased sperm limitation, in conjunction with adult population decline, may have severe consequences for coral reproductive success. Impaired sexual reproduction will further challenge corals by inhibiting population recovery and adaptation potential.

Projected Near-Future Levels of Temperature and pCO2 Reduce Coral Fertilization Success

PubMed Central

Albright, Rebecca; Mason, Benjamin

2013-01-01

Increases in atmospheric carbon dioxide (pCO2) are projected to contribute to a 1.1–6.4°C rise in global average surface temperatures and a 0.14–0.35 reduction in the average pH of the global surface ocean by 2100. If realized, these changes are expected to have negative consequences for reef-building corals including increased frequency and severity of coral bleaching and reduced rates of calcification and reef accretion. Much less is known regarding the independent and combined effects of temperature and pCO2 on critical early life history processes such as fertilization. Here we show that increases in temperature (+3°C) and pCO2 (+400 µatm) projected for this century negatively impact fertilization success of a common Indo-Pacific coral species, Acropora tenuis. While maximum fertilization did not differ among treatments, the sperm concentration required to obtain 50% of maximum fertilization increased 6- to 8- fold with the addition of a single factor (temperature or CO2) and nearly 50- fold when both factors interact. Our results indicate that near-future changes in temperature and pCO2 narrow the range of sperm concentrations that are capable of yielding high fertilization success in A. tenuis. Increased sperm limitation, in conjunction with adult population decline, may have severe consequences for coral reproductive success. Impaired sexual reproduction will further challenge corals by inhibiting population recovery and adaptation potential. PMID:23457572

Herbarium specimens, photographs, and field observations show Philadelphia area plants are responding to climate change.

PubMed

Panchen, Zoe A; Primack, Richard B; Anisko, Tomasz; Lyons, Robert E

2012-04-01

The global climate is changing rapidly and is expected to continue changing in coming decades. Studying changes in plant flowering times during a historical period of warming temperatures gives us a way to examine the impacts of climate change and allows us to predict further changes in coming decades. The Greater Philadelphia region has a long and rich history of botanical study and documentation, with abundant herbarium specimens, field observations, and botanical photographs from the mid-1800s onward. These extensive records also provide an opportunity to validate methodologies employed by other climate change researchers at a different biogeographical area and with a different group of species. Data for 2539 flowering records from 1840 to 2010 were assessed to examine changes in flowering response over time and in relation to monthly minimum temperatures of 28 Piedmont species native to the Greater Philadelphia region. Regression analysis of the date of flowering with year or with temperature showed that, on average, the Greater Philadelphia species studied are flowering 16 d earlier over the 170-yr period and 2.7 d earlier per 1°C rise in monthly minimum temperature. Of the species studied, woody plants with short flowering duration are the best indicators of a warming climate. For monthly minimum temperatures, temperatures 1 or 2 mo prior to flowering are most significantly correlated with flowering time. Studies combining herbarium specimens, photographs, and field observations are an effective method for detecting the effects of climate change on flowering times.

Parasites and Holocene sea-level rise: Recurrent upsurges in trematode infestation linked to repeated flooding events in the Adriatic Sea

NASA Astrophysics Data System (ADS)

Scarponi, Daniele; Azzarone, Michele; Kowalewski, Michał; Huntley, John Warren

2017-04-01

The accelerating increase in global temperature and concomitant sea level rise may result in an increased prevalence (i.e. infestation frequency) of many pathogens and parasites. Using the Holocene brackish deposits of the Po Plain, we evaluate this issue from a historical perspective by documenting temporal changes in trematode infestation of mollusk hosts during high-frequency (102-103 yrs) sea-level fluctuations that took place over the most recent millennia. During that time interval, the dominant bivalve species, Abra segmentum, was frequently infested by trematodes. Median body size was significantly larger in infested individuals (p = 2.21*10-34), likely reflecting accumulation of parasites with ontogenetic age. Prevalence estimates were significantly elevated (p < 0.01) in samples of A. segmentum associated with flooding surfaces and significantly depressed (p < 0.01) in intervening samples. In contrast, temporal trends in host body size, host availability, salinity, diversity, turnover, and community structure did not correlate significantly with parasite prevalence. The results reported here reinforce the recently proposed hypothesis that increasing trematode prevalence is linked to flooding events, a pattern now documented in shallow marine and estuarine settings on two continents, in both modern and fossil taxa. Consequently, the ongoing anthropogenic warming and sea-level rise is expected to trigger a significant upsurge in trematode prevalence, resulting in suppressed fecundity of common benthic organisms and negative impacts on marine ecosystems and ecosystem services.

On Temperature Rise Within the Shear Bands in Bulk Metallic Glasses

NASA Astrophysics Data System (ADS)

Bazlov, A. I.; Churyumov, A. Yu.; Buchet, M.; Louzguine-Luzgin, D. V.

2018-05-01

Room temperature deformation process in a bulk metallic glassy sample was studied by using a hydraulic thermomechanical simulator. The temperature rise during each separate shear band propagation event was measured with a high data acquisition frequency by a thermocouple welded to the sample. Calculation showed that when propagation of the well developed shear bands takes place along the entire sample the temperature inside the shear band should be close to the glass-transition temperature. It was also possible to resolve the temporal stress distribution and a double-stage character of stress drops was also observed. The obtained results are compared with the literature data obtained by infrared camera measurements and the results of finite elements modeling.

On Temperature Rise Within the Shear Bands in Bulk Metallic Glasses

NASA Astrophysics Data System (ADS)

Bazlov, A. I.; Churyumov, A. Yu.; Buchet, M.; Louzguine-Luzgin, D. V.

2018-03-01

Room temperature deformation process in a bulk metallic glassy sample was studied by using a hydraulic thermomechanical simulator. The temperature rise during each separate shear band propagation event was measured with a high data acquisition frequency by a thermocouple welded to the sample. Calculation showed that when propagation of the well developed shear bands takes place along the entire sample the temperature inside the shear band should be close to the glass-transition temperature. It was also possible to resolve the temporal stress distribution and a double-stage character of stress drops was also observed. The obtained results are compared with the literature data obtained by infrared camera measurements and the results of finite elements modeling.

Research on particulate filter simulation and regeneration control strategy

NASA Astrophysics Data System (ADS)

Dawei, Qu; Jun, Li; Yu, Liu

2017-03-01

This paper reports a DPF (Diesel Particulate Filter) collection mathematical model for a new regeneration control strategy. The new strategy is composed by main parts, such as regeneration time capturing, temperature rising strategy and regeneration control strategy. In the part of regeneration time capturing, a multi-level regeneration capturing method is put forward based on the combined effect of the PM (Particulate Matter) loading, pressure drop and fuel consumption. The temperature rising strategy proposes the global temperature for all operating conditions. The regeneration control process considers the particle loading density, temperature and oxygen respectively. Based on the analysis of the initial overheating, runaway temperature and local hot spot, the final control strategy is established.

A hot future for European droughts

NASA Astrophysics Data System (ADS)

Teuling, Adriaan J.

2018-05-01

Low soil moisture conditions can induce drought but also elevate temperatures. Detailed modelling of the drought-temperature link now shows that rising global temperature will bring drier soils and higher heatwave temperatures in Europe.

Baccalaureate Expectations of Community College Students: Socio-Demographic, Motivational, and Contextual Influences

ERIC Educational Resources Information Center

Wang, Xueli

2013-01-01

Background/Context: Although much research has dealt with the factors that influence educational expectations, few studies have addressed recent high school graduates who attend community colleges as their first postsecondary institutions. As the costs associated with attending a four-year institution keep rising, community colleges increasingly…

Spending our water and soils for food security

USDA-ARS?s Scientific Manuscript database

A third of the world’s population suffers from food insecurity. With an expected 2 billion population increase in the next few decades that number is expected to rise significantly, leading to more people that are insecure and starving unless our soils can produce more food. Added to the problem are...

Millimeter waves thermally alter the firing rate of the Lymnaea pacemaker neuron

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

Alekseev, S.I.; Kochetkova, N.V.; Ziskin, M.C.

1997-05-01

The effects of millimeter waves (mm-waves, 75 GHz) and temperature elevation on the firing rate of the BP-4 pacemaker neuron of the pond snail Lymnaea stagnalis were studied by using microelectrode techniques. The open end of a rectangular waveguide covered with a thin Teflon film served as a radiator. Specific absorption rates (SARs), measured in physiological solution at the radiator outlet, ranged from 600 to 4,200 W/kg, causing temperature rises from 0.3 to 2.2 C, respectively. Irradiation at an SAR of 4,200 W/kg caused a biphasic change in the firing rate, i.e., a transient decrease in the firing rate followedmore » by a gradual increase to a new level that was 68 {+-} 21% above control. The biphasic changes in the firing rate were reproduced by heating under the condition that the magnitude (2 C) and the rate of temperature rise were equal to those produced by the irradiation. The addition of 0.05 mM of ouabain caused the disappearance of transient responses of the neuron to the irradiation. It was shown that the rate of temperature rise played an important role in the development of a transient neuronal response. The threshold stimulus for a transient response of the BP-4 neutron found in warming experiments was a temperature rise of 0.0025 C/s.« less

Simulation of Impact on a Ductile Polymer Plate

NASA Technical Reports Server (NTRS)

Cremona, Rebecca L.; Hinkley, Jeffrey A.

2005-01-01

Explicit finite element calculations were used to visualize the deformation and temperature rise in an elastic-plastic plate impacted by a rigid projectile. Results were compared to results of experiments involving ballistic penetration of a "self-healing" thermoplastic. The calculated temperature rise agreed well with the experimental observation, but the total energy absorbed in the penetration event was underestimated in the calculation, which neglected friction.

Pulp chamber temperature rise during curing of resin-based composites with different light-curing units.

PubMed

Durey, Kathryn; Santini, Ario; Miletic, Vesna

2008-01-01

The purpose of the present study was to measure the intrapulpal temperature rise occurring during polymerisation of different shades of resin-based composites (RBCs), and two light-emitting diode (LED) units. Seventy non-carious permanent molars, that had been extracted for orthodontic purposes and stored in 2% thymol for not more than four months, were selected. Patient age range was 11-18 years. Standard cavity preparation with standardised remaining dentine thickness and placement of thermocouples (TCs) was prepared using a novel split-tooth technique. Cavities were filled with one of two shades of RBC (A2 and C4, Filtek Z250, 3M ESPE, Seefeld, Germany), and cured with two LED high-intensity units (Elipar Freelight2, 3M ESPE, Seefeld, Germany; Bluephase, Ivoclar Vivadent, Schaan, Liechtenstein) and a conventional halogen light-curing unit (LCU) (Prismetics Lite 2, Dentsply, Weybridge, Surrey, UK) as a control. Pulp temperature rises during bonding [A2 results: H;2.67/0.48:E;5.24/1.32;B;5.99/1.61] were always greater than during RBC curing [A2 results: 2.44/0.63;E3.34/0.70;B3.38/0.60], and these were significant for both LED lights but not for the halogen control, irrespective of shade (Mann-Whitney test: 95% confidence limits). Temperature rises were at times in excess of the values normally quoted as causing irreversible pulp damage. Pulp temperature rises during bonding were higher with the LED lights than with the halogen control. There was no significant difference in temperature rise between the two LED lights when bonding but there was a significant difference between the two LED lights and the halogen control LCUs (Kruskal-Wallis Test: 95% confidence limits). The results support the view that there is a potential risk for heat-induced pulpal injury when light-curing RBCs. The risk is greater during bonding and with high energy, as compared to low-energy output systems. As the extent of tolerable thermal trauma by the pulp tissues is unknown, care and consideration should be given to the choice of LCU and the exposure time when curing RBCs, and especially during bonding.

Temperature in the anterior chamber during phacoemulsification.

PubMed

Suzuki, Hisaharu; Oki, Kotaro; Igarashi, Tsutomu; Shiwa, Toshihiko; Takahashi, Hiroshi

2014-05-01

To evaluate changes in the aqueous humor temperature using 2 phacoemulsification units (Stellaris 28.5 kHz device and Whitestar Signature 40 kHz device). Nippon Medical School, Musashikosugi Hospital, Kawasaki City, Kanagawa, Japan. Experimental study. Aqueous humor temperatures were measured with a temperature probe set in the anterior chamber during ultrasound (US) oscillation in porcine eyes under 5 conditions. Continuous longitudinal oscillation caused a rapid rise in aqueous humor temperature, while the pulse and elliptical modes suppressed temperature elevation. Reducing the number of US tip vibrations did not reduce the temperature in the anterior chamber. However, raising the vacuum setting allowed the aspirations to rise to the set value, thereby lowering the temperature in the anterior chamber. Because differences in the phacoemulsification settings can lead to temperature elevations in the anterior chamber, surgeons must carefully monitor these settings to prevent corneal tissue damage. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

The Impacts of a 2-Degree Rise in Global Temperatures upon Gas-Phase Air Pollutants in Europe

NASA Astrophysics Data System (ADS)

Watson, Laura; Josse, Béatrice; Marecal, Virginie; Lacressonnière, Gwendoline; Vautard, Robert; Gauss, Michael; Engardt, Magnuz; Nyiri, Agnes; Siour, Guillaume

2014-05-01

The 15th session of the Conference of Parties (COP 15) in 2009 ratified the Copenhagen Accord, which "recognises the scientific view that" global temperature rise should be held below 2 degrees C above pre-industrial levels in order to limit the impacts of climate change. Due to the fact that a 2-degree limit has been frequently referred to by policy makers in the context of the Copenhagen Accord and many other high-level policy statements, it is important that the impacts of this 2-degree increase in temperature are adequately analysed. To this end, the European Union sponsored the project IMPACT2C, which uses a multi-disciplinary international team to assess a wide variety of impacts of a 2-degree rise in global temperatures. For example, this future increase in temperature is expected to have a significant influence upon meteorological conditions such as temperature, precipitation, and wind direction and intensity; which will in turn affect the production, deposition, and distribution of air pollutants. For the first part of the air quality analysis within the IMPACT2C project, the impact of meteorological forcings on gas phase air pollutants over Europe was studied using four offline atmospheric chemistry transport models. Two sets of meteorological forcings were used for each model: reanalysis of past observation data and global climate model output. Anthropogenic emissions of ozone precursors for the year 2005 were used for all simulations in order to isolate the impact of meteorology and assess the robustness of the results across the different models. The differences between the simulations that use reanalysis of past observation data and the simulations that use global climate model output show how global climate models modify climate hindcasts by boundary conditions inputs: information that is necessary in order to interpret simulations of future climate. The baseline results were assessed by comparison with AirBase (Version 7) measurement data, and were then used as a reference for an analysis of future climate scenarios upon European air quality. The future scenarios included two types of emission data for the year 2050: one set of emission data corresponding to a current legislation scenario and another corresponding to a scenario with a maximum feasible reduction in emissions. The future scenarios were run for the time period that corresponds to a 2-degree increase in global temperatures; a time period that varies depending on which global climate model is used. In order to calculate the effect of climate change on emission reduction scenarios, the "climate penalty", the future simulations were compared to a simulation using the same future emissions but with current (2005) climate. Results show that climate change will have consequential impacts with regards to the production and geographical distribution of ozone and nitrogen oxides.

Experimental Study on the Electrical Conductivity of Pyroxene Andesite at High Temperature and High Pressure

NASA Astrophysics Data System (ADS)

Hui, KeShi; Dai, LiDong; Li, HePing; Hu, HaiYing; Jiang, JianJun; Sun, WenQing; Zhang, Hui

2017-03-01

The electrical conductivity of pyroxene andesite was in situ measured under conditions of 1.0-2.0 GPa and 673-1073 K using a YJ-3000t multi-anvil press and Solartron-1260 Impedance/Gain-phase analyzer. Experimental results indicate that the electrical conductivities of pyroxene andesite increase with increasing temperature, and the electrical conductivities decrease with the rise of pressure, and the relationship between electrical conductivity ( σ) and temperature ( T) conforms to an Arrhenius relation within a given pressure and temperature range. When temperature rises up to 873-923 K, the electrical conductivities of pyroxene andesite abruptly increase, and the activation enthalpy increases at this range, which demonstrates that pyroxene andesite starts to dehydrate. By the virtue of the activation enthalpy (0.35-0.42 eV) and the activation volume (-6.75 ± 1.67 cm3/mole) which characterizes the electrical properties of sample after dehydration, we consider that the conduction mechanism is the small polaron conduction before and after dehydration, and that the rise of carrier concentration is the most important reason of increased electrical conductivity.

Measuring temperature rise during orthopaedic surgical procedures.

PubMed

Manoogian, Sarah; Lee, Adam K; Widmaier, James C

2016-09-01

A reliable means for measuring temperatures generated during surgical procedures is needed to recommend best practices for inserting fixation devices and minimizing the risk of osteonecrosis. Twenty four screw tests for three surgical procedures were conducted using the four thermocouples in the bone and one thermocouple in the screw. The maximum temperature rise recorded from the thermocouple in the screw (92.7±8.9°C, 158.7±20.9°C, 204.4±35.2°C) was consistently higher than the average temperature rise recorded in the bone (31.8±9.3°C, 44.9±12.4°C, 77.3±12.7°C). The same overall trend between the temperatures that resulted from three screw insertion procedures was recorded with significant statistical analyses using either the thermocouple in the screw or the average of several in-bone thermocouples. Placing a single thermocouple in the bone was determined to have limitations in accurately comparing temperatures from different external fixation screw insertion procedures. Using the preferred measurement techniques, a standard screw with a predrilled hole was found to have the lowest maximum temperatures for the shortest duration compared to the other two insertion procedures. Future studies evaluating bone temperature increase need to use reliable temperature measurements for recommending best practices to surgeons. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Temperature Effects on Force and Actin⁻Myosin Interaction in Muscle: A Look Back on Some Experimental Findings.

PubMed

Ranatunga, K W

2018-05-22

Observations made in temperature studies on mammalian muscle during force development, shortening, and lengthening, are re-examined. The isometric force in active muscle goes up substantially on warming from less than 10 °C to temperatures closer to physiological (>30 °C), and the sigmoidal temperature dependence of this force has a half-maximum at ~10 °C. During steady shortening, when force is decreased to a steady level, the sigmoidal curve is more pronounced and shifted to higher temperatures, whereas, in lengthening muscle, the curve is shifted to lower temperatures, and there is a less marked increase with temperature. Even with a small rapid temperature-jump (T-jump), force in active muscle rises in a definitive way. The rate of tension rise is slower with adenosine diphosphate (ADP) and faster with increased phosphate. Analysis showed that a T-jump enhances an early, pre-phosphate release step in the acto-myosin (crossbridge) ATPase cycle, thus inducing a force-rise. The sigmoidal dependence of steady force on temperature is due to this endothermic nature of crossbridge force generation. During shortening, the force-generating step and the ATPase cycle are accelerated, whereas during lengthening, they are inhibited. The endothermic force generation is seen in different muscle types (fast, slow, and cardiac). The underlying mechanism may involve a structural change in attached myosin heads and/or their attachments on heat absorption.

Temperature Effects on Force and Actin–Myosin Interaction in Muscle: A Look Back on Some Experimental Findings

PubMed Central

Ranatunga, K. W.

2018-01-01

Observations made in temperature studies on mammalian muscle during force development, shortening, and lengthening, are re-examined. The isometric force in active muscle goes up substantially on warming from less than 10 °C to temperatures closer to physiological (>30 °C), and the sigmoidal temperature dependence of this force has a half-maximum at ~10 °C. During steady shortening, when force is decreased to a steady level, the sigmoidal curve is more pronounced and shifted to higher temperatures, whereas, in lengthening muscle, the curve is shifted to lower temperatures, and there is a less marked increase with temperature. Even with a small rapid temperature-jump (T-jump), force in active muscle rises in a definitive way. The rate of tension rise is slower with adenosine diphosphate (ADP) and faster with increased phosphate. Analysis showed that a T-jump enhances an early, pre-phosphate release step in the acto-myosin (crossbridge) ATPase cycle, thus inducing a force-rise. The sigmoidal dependence of steady force on temperature is due to this endothermic nature of crossbridge force generation. During shortening, the force-generating step and the ATPase cycle are accelerated, whereas during lengthening, they are inhibited. The endothermic force generation is seen in different muscle types (fast, slow, and cardiac). The underlying mechanism may involve a structural change in attached myosin heads and/or their attachments on heat absorption. PMID:29786656

Thermal physiology, disease, and amphibian declines on the eastern slopes of the Andes.

PubMed

Catenazzi, Alessandro; Lehr, Edgar; Vredenburg, Vance T

2014-04-01

Rising temperatures, a widespread consequence of climate change, have been implicated in enigmatic amphibian declines from habitats with little apparent human impact. The pathogenic fungus Batrachochytrium dendrobatidis (Bd), now widespread in Neotropical mountains, may act in synergy with climate change causing collapse in thermally stressed hosts. We measured the thermal tolerance of frogs along a wide elevational gradient in the Tropical Andes, where frog populations have collapsed. We used the difference between critical thermal maximum and the temperature a frog experiences in nature as a measure of tolerance to high temperatures. Temperature tolerance increased as elevation increased, suggesting that frogs at higher elevations may be less sensitive to rising temperatures. We tested the alternative pathogen optimal growth hypothesis that prevalence of the pathogen should decrease as temperatures fall outside the optimal range of pathogen growth. Our infection-prevalence data supported the pathogen optimal growth hypothesis because we found that prevalence of Bd increased when host temperatures matched its optimal growth range. These findings suggest that rising temperatures may not be the driver of amphibian declines in the eastern slopes of the Andes. Zoonotic outbreaks of Bd are the most parsimonious hypothesis to explain the collapse of montane amphibian faunas; but our results also reveal that lowland tropical amphibians, despite being shielded from Bd by higher temperatures, are vulnerable to climate-warming stress. © 2013 Society for Conservation Biology.

Coupling Monte Carlo simulations with thermal analysis for correcting microdosimetric spectra from a novel micro-calorimeter

NASA Astrophysics Data System (ADS)

Fathi, K.; Galer, S.; Kirkby, K. J.; Palmans, H.; Nisbet, A.

2017-11-01

The high uncertainty in the Relative Biological Effectiveness (RBE) values of particle therapy beam, which are used in combination with the quantity absorbed dose in radiotherapy, together with the increase in the number of particle therapy centres worldwide necessitate a better understating of the biological effect of such modalities. The present novel study is part of performance testing and development of a micro-calorimeter based on Superconducting QUantum Interference Devices (SQUIDs). Unlike other microdosimetric detectors that are used for investigating the energy distribution, this detector provides a direct measurement of energy deposition at the micrometre scale, that can be used to improve our understanding of biological effects in particle therapy application, radiation protection and environmental dosimetry. Temperature rises of less than 1μK are detectable and when combined with the low specific heat capacity of the absorber at cryogenic temperature, extremely high energy deposition sensitivity of approximately 0.4 eV can be achieved. The detector consists of 3 layers: tissue equivalent (TE) absorber, superconducting (SC) absorber and silicon substrate. Ideally all energy would be absorbed in the TE absorber and heat rise in the superconducting layer would arise due to heat conduction from the TE layer. However, in practice direct particle absorption occurs in all 3 layers and must be corrected for. To investigate the thermal behaviour within the detector, and quantify any possible correction, particle tracks were simulated employing Geant4 (v9.6) Monte Carlo simulations. The track information was then passed to the COMSOL Multiphysics (Finite Element Method) software. The 3D heat transfer within each layer was then evaluated in a time-dependent model. For a statistically reliable outcome, the simulations had to be repeated for a large number of particles. An automated system has been developed that couples Geant4 Monte Carlo output to COMSOL for determining the expected distribution of proton tracks and their thermal contribution within the detector. The correction factor for a 3.8 MeV proton pencil beam was determined and applied to the expected spectra. The corrected microdosimetric spectra was shown to have a good agreement with the ideal spectra.

The Effect of Insertion Technique on Temperatures for Standard and Self-Drilling External Fixation Pins.

PubMed

Manoogian, Sarah; Lee, Adam K; Widmaier, James C

2017-08-01

No studies have assessed the effects of parameters associated with insertion temperature in modern self-drilling external fixation pins. The current study assessed how varying the presence of irrigation, insertion speed, and force impacted the insertion temperatures of 2 types of standard and self-drilling external fixation half pins. Seventy tests were conducted with 10 trials for 4 conditions on self-drilling pins, and 3 conditions for standard pins. Each test used a thermocouple inside the pin to measure temperature rise during insertion. Adding irrigation to the standard pin insertion significantly lowered the maximum temperature (P <0.001). Lowering the applied force for the standard pin did not have a significant change in temperature rise. Applying irrigation during the self-drilling pin tests dropped average rise in temperature from 151.3 ± 21.6°C to 124.1 ± 15.3°C (P = 0.005). When the self-drilling pin insertion was decreased considerably from 360 to 60 rpm, the temperature decreased significantly from 151.3 ± 21.6°C to 109.6 ± 14.0°C (P <0.001). When the force applied increased significantly, the corresponding self-drilling pin temperature increase was not significant. The standard pin had lower peak temperatures than the self-drilling pin for all conditions. Moreover, slowing down the insertion speed and adding irrigation helped mitigate the temperature increase of both pin types during insertion.

Effects of atmospheric temperature and humidity on outbreak of diseases.

PubMed

Choi, Sung Hyuk; Lee, Sung Woo; Hong, Yun Sik; Kim, Su Jin; Kim, Nak Hoon

2007-12-01

The present study aimed to determine the plausibility of forecasting the outbreak of diseases based on the weather by analysing the impact of atmospheric temperature and humidity on the occurrence of different diseases. The subjects of the present study were the 30,434 patients who visited the ED in 1 year from 1 February 2005 to 3 February 2006. The present study analysed the correlation between the daily number of patients who suffered from 22 types of traumatic and non-traumatic diseases and the data on atmospheric temperature and humidity provided by the Korea Meteorological Administration. With traumatic disease, the occurrence tended to increase in proportion to the rise in temperature and humidity; whereas with non-traumatic disease, the occurrence tended to increase according to the rise in temperature, irrespective of humidity changes. The research on the impact of atmospheric temperature and humidity on different diseases revealed a high level of distribution of most diseases in an environment with high temperature and humidity. However, in the case of pulmonary diseases and trauma to multiple body regions, the occurrence increased in environments with low temperature and high humidity for pulmonary diseases, and with low temperature and low humidity for trauma to multiple body regions. Most diseases tend to increase in proportion to the rise in atmospheric temperature whereas being less affected by humidity. However, an increase in humidity in an optimum range of atmospheric temperature (12 degrees C or higher) triggers an increase in the occurrence of diseases.

POWER BREEDER REACTOR

DOEpatents

Monson, H.O.

1960-11-22

An arrangement is offered for preventing or minimizing the contraction due to temperature rise, of a reactor core comprising vertical fuel rods in sodium. Temperature rise of the fuel rods would normally make them move closer together by inward bowing, with a resultant undesired increase in reactivity. According to the present invention, assemblies of the fuel rods are laterally restrained at the lower ends of their lower blanket sections and just above the middle of the fuel sections proper of the rods, and thus the fuel sections move apart, rather than together, with increase in temperature.

Thermoregulatory challenges in the habitat of the world's smallest tortoise, Chersobius signatus.

PubMed

Loehr, Victor J T

2018-01-01

Ectotherms have various means of dealing with low environmental temperatures, but relatively few species have been rigorously investigated. Consequently, we have little information to predict how ectotherm populations might respond to global temperature changes. Tortoises from temperate and subtropical regions often overcome periodically cool conditions by hibernation, but speckled dwarf tortoises (Chersobius signatus) need to remain active to exploit ephemeral resources in their arid winter-rainfall habitat. This study investigated how dwarf tortoises cope with low temperatures in winter and spring, by measuring thermal habitat quality and thermoregulation based on differently-sized operative temperature models in sun, shade, and in deep crevices. Investigations continued in summer and autumn to obtain a year-round picture of thermoregulatory challenges. Although large models (i.e., larger than dwarf tortoises) were expected to have lower operative temperatures than smaller models, due to the former's larger thermal inertia, all model sizes had similar temperatures. Hence, the species' small body size does not appear constrained by obtainable body temperatures in cool seasons. Nevertheless, low operative temperatures in winter posed a challenge for the tortoises, which reached their field-preferred body temperature for an average of only 0.8-0.9h per day. Moreover, a low thermoregulation effectiveness suggested that tortoises traded-off physiological benefits of favourable body temperatures against predation risk. Spring and autumn provided higher temperatures, but summer caused the greatest thermoregulatory challenge. Although summer body temperatures were closer to field-preferred body temperature than in any other season, tortoises required rock crevices to avoid overheating. The small size of dwarf tortoises might help them utilise crevices. In summer, maximum operative temperatures in crevices were similar to field-preferred body temperature, indicating that an increase in environmental temperatures might be detrimental to dwarf tortoises. In light of projected temperature rises, future studies should assess if dwarf tortoises can cope with higher environmental temperatures in summer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phenology changes in the mayfly Ephemera danica in response to water temperature variations in the River Dove, UK

NASA Astrophysics Data System (ADS)

Johnson, Matthew; Everall, Nicholas; Wilby, Robert

2015-04-01

Water temperature in rivers is critical to aquatic life. Climate and environmental change can elevate river temperatures to levels that stress fish, but impacts on other aquatic organisms are not well understood. In particular, rising temperatures are expected to alter the phenology of aquatic insects at levels substantially below those required to stress fish species. The phenology of the mayfly Ephemera danica, a large burrowing species that is widespread throughout Europe, is known to be sensitive to temperature change. To assess the temporal and spatial variability in mayfly emergence, E. danica were monitored at two reaches in the River Dove, English Peak District over the period 2007 to 2013. Variations in Growing Degree Days (GDDs) were modelled for an upstream site with an annual temperature range in excess of 15 ° C (Beresford Dale) and a downstream site, dominated by near constant discharges of cool groundwater with an annual range less than 8 ° C (Dovedale). The emergence of E. danica was strongly related to GDDs at each site. E. danica usually remains in an aquatic larval stage for two years before emerging in its adult, terrestrial form. However, after particularly warm summers in Beresford Dale, E. danica was recorded to emerge after only one year in its aquatic form. Following the particularly wet/cold year of 2012, E. danica began to revert back to a bi-annual cycle. In Dovedale, an average of 374 fewer GDDs were accumulated in comparison to Beresford Dale. As a result, E. danica maintained a two-year growth cycle throughout the monitoring period despite the phenology changes observed 8 km upstream at Beresford. Changes to insect phenology are significant because populations with a one-year cycle are potentially more vulnerable to adverse weather when the majority of the population is in terrestrial form. Also, altering the growth, development and size of insects affects reproductive success with implications for population dynamics. Data from the present study suggest that habitats near cool groundwater may provide important refugia for populations of insects, potentially delaying permanent shifts in phenology under climate change. Conventional monitoring of both water temperature and invertebrates, as used by regulatory authorities in the UK, did not identify the changes in insect phenology or the association between phenology and water temperature. Therefore, new monitoring strategies are required in order to identify important changes in aquatic populations in response to rising temperatures.

75 FR 6616 - Endangered and Threatened Wildlife; Notice of 90-Day Finding on a Petition to List 83 Species of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-10

... ocean acidification, increasing storm intensities, changes in precipitation, and sea-level rise. The... Indian Ocean are expected to rise above 1998 levels within a few decades (Sheppard, 2003, as cited by the... greenhouse gas concentrations to levels that do not jeopardize these species. The petition also asserts that...

Is frictional heating needed to cause dramatic weakening of nanoparticle gouge during seismic slip? Insights from friction experiments with variable thermal evolutions

NASA Astrophysics Data System (ADS)

Yao, Lu; Ma, Shengli; Niemeijer, André R.; Shimamoto, Toshihiko; Platt, John D.

2016-07-01

To examine whether faults can be lubricated by preexisting and newly formed nanoparticles, we perform high-velocity friction experiments on periclase (MgO) nanoparticles and on bare surfaces of Carrara marble cylinders/slices, respectively. Variable temperature conditions were simulated by using host blocks of different thermal conductivities. When temperature rises are relatively low, we observe high friction in nano-MgO tests and unexpected slip strengthening following initial weakening in marble slice tests, suggesting that the dominant weakening mechanisms are of thermal origin. Solely the rolling of nanoparticles without significant temperature rise is insufficient to cause dynamic fault weakening. For nano-MgO experiments, comprehensive investigations suggest that flash heating is the most likely weakening mechanism. In marble experiments, flash heating controls the unique evolutions of friction, and the competition between bulk temperature rise and wear-induced changes of asperity contact numbers seems to strongly affect the efficiency of flash heating.

SAR and temperature distribution in the rat head model exposed to electromagnetic field radiation by 900 MHz dipole antenna.

PubMed

Yang, Lei; Hao, Dongmei; Wu, Shuicai; Zhong, Rugang; Zeng, Yanjun

2013-06-01

Rats are often used in the electromagnetic field (EMF) exposure experiments. In the study for the effect of 900 MHz EMF exposure on learning and memory in SD rats, the specific absorption rate (SAR) and the temperature rise in the rat head are numerically evaluated. The digital anatomical model of a SD rat is reconstructed with the MRI images. Numerical method as finite difference time domain has been applied to assess the SAR and the temperature rise during the exposure. Measurements and simulations are conducted to characterize the net radiated power of the dipole to provide a precise dosimetric result. The whole-body average SAR and the localized SAR averaging over 1, 0.5 and 0.05 g mass for different organs/tissues are given. It reveals that during the given exposure experiment setup, no significant temperature rise occurs. The reconstructed anatomical rat model could be used in the EMF simulation and the dosimetric result provides useful information for the biological effect studies.

Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

NASA Astrophysics Data System (ADS)

Bohn, Friedrich J.; May, Felix; Huth, Andreas

2018-03-01

Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP). It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q) and a species distribution index (ΩAWP). ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length). The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a development, one could plant below the closed canopy of even-aged, pioneer trees a climax-species-rich understorey that will build the canopy of the mature forest. This study highlights that forest structure and species composition are both relevant for understanding the temperature sensitivity of wood production.

Forecasting the evolution in the mixing regime of a deep subalpine lake under climate change scenarios through numerical modelling (Lake Maggiore, Northern Italy/Southern Switzerland)

NASA Astrophysics Data System (ADS)

Fenocchi, Andrea; Rogora, Michela; Sibilla, Stefano; Ciampittiello, Marzia; Dresti, Claudia

2018-01-01

The impact of air temperature rise is eminent for the large deep lakes in the Italian subalpine district, climate change being caused there by both natural phenomena and anthropogenic greenhouse-gases (GHG) emissions. These oligomictic lakes are experiencing a decrease in the frequency of winter full turnover and an intensification of stability. As a result, hypolimnetic oxygen concentrations are decreasing and nutrients are accumulating in bottom water, with effects on the whole ecosystem functioning. Forecasting the future evolution of the mixing pattern is relevant to assess if a reduction in GHG releases would be able to revert such processes. The study focuses on Lake Maggiore, for which the thermal structure evolution under climate change in the 2016-2085 period was assessed through numerical simulations, performed with the General Lake Model (GLM). Different prospects of regional air temperature rise were considered, given by the Swiss Climate Change Scenarios CH2011. Multiple realisations were performed for each scenario to obtain robust statistical predictions, adopting random series of meteorological data produced with the Vector-Autoregressive Weather Generator (VG). Results show that a reversion in the increasing thermal stability would be possible only if global GHG emissions started to be reduced by 2020, allowing an equilibrium mixing regime to be restored by the end of the twenty-first century. Otherwise, persistent lack of complete-mixing, severe water warming and extensive effects on water quality are to be expected for the centuries to come. These projections can be extended to the other lakes in the subalpine district.

Modern high powered led curing lights and their effect on pulp chamber temperature of bulk and incrementally cured composite resin.

PubMed

Oberholzer, T G; Makofane, M E; du Preez, I C; George, R

2012-06-01

Pulpal temperature changes induced by modern high powered light emitting diodes (LEDs) are of concern when used to cure composite resins. This study showed an increase in pulp chamber temperature with an increase in power density for all light cure units (LCU) when used to bulk cure composite resin. Amongst the three LEDs tested, the Elipar Freelight-2 recorded the highest temperature changes. Bulk curing recorded a significantly larger rise in pulp chamber temperature change than incrementally cured resin for all light types except for the Smartligh PS. Both the high powered LED and the conventional curing units can generate heat. Though this temperature rise may not be sufficient to cause irreversible pulpal damage, it would be safer to incrementally cure resins.

The temperature of unheated bodies in a high-speed gas stream

NASA Technical Reports Server (NTRS)

Eckert, E; Weise, W

1941-01-01

The present report deals with temperature measurements on cylinders of 0.2 to 3 millimeters diameter in longitudinal and transverse air flow at speeds of 100 to 300 meters per second. Within the explored test range, that is, the probable laminar boundary layer region, the temperature of the cylinders in axial flow is practically independent of the speed and in good agreement with Pohlhausen's theoretical values; Whereas, in transverse flow, cylinders of certain diameter manifest a close relationship with speed, the ratio of the temperature above the air of the body to the adiabatic stagnation temperature decreases with rising speed and then rises again from a Mach number of 0.6. The importance of this "specific temperature" of the body for heat-transfer studies at high speed is discussed.

The rise and fall of the "marine heat wave" off Western Australia during the summer of 2010/2011

NASA Astrophysics Data System (ADS)

Pearce, Alan F.; Feng, Ming

2013-02-01

Record high ocean temperatures were experienced along the Western Australian coast during the austral summer of 2010/2011. Satellite-derived sea surface temperature (SST) anomalies in February 2011 peaked at 3 °C above the long-term monthly means over a wide area from Ningaloo (22°S) to Cape Leeuwin (34°S) along the coast and out to > 200 km offshore. Hourly temperature measurements at a number of mooring sites along the coast revealed that the temperature anomalies were mostly trapped in the surface mixed layer, with peak nearshore temperatures rising to ~ 5 °C above average in the central west coastal region over a week encompassing the end of February and early March, resulting in some devastating fish kills as well as temporary southward range extensions of tropical fish species and megafauna such as whale sharks and manta rays. The elevated temperatures were a result of a combination of a record strength Leeuwin Current, a near-record La Niña event, and anomalously high air-sea heat flux into the ocean even though the SST was high. This heat wave was an unprecedented thermal event in Western Australian waters, superimposed on an underlying long-term temperature rise.

Temperature increase in human cadaver retina during direct illumination by femtosecond laser pulses.

PubMed

Sun, Hui; Mikula, Eric; Kurtz, Ronald M; Juhasz, Tibor

2010-04-01

Femtosecond lasers have been approved by the US Food and Drug Administration for ophthalmic surgery, including use in creating corneal flaps in LASIK surgery. During normal operation, approximately 50% to 60% of laser energy may pass beyond the cornea, with potential effects on the retina. As a model for retinal laser exposure during femtosecond corneal surgery, we measured the temperature rise in human cadaver retinas during direct illumination by the laser. The temperature increase induced by a 150-kHz iFS Advanced Femtosecond Laser (Abbott Medical Optics) in human cadaver retinas was measured in situ using an infrared thermal imaging camera. To model the geometry of the eye during the surgery, an approximate 11x11-mm excised section of human cadaver retina was placed 17 mm behind the focus of the laser beam. The temperature field was observed in 10 cadaver retina samples at energy levels ranging from 0.4 to 1.6 microJ (corresponding approximately to surgical energies of 0.8 to 3.2 microJ per pulse). Maximal temperature increases up to 1.15 degrees C (corresponding to 3.2 microJ and 52-second illumination) were observed in the cadaver retina sections with little variation in temperature profiles between specimens for the same laser energy illumination. The commercial iFS Advanced Femtosecond Laser operating with pulse energies at approximately the lower limit of the range evaluated in this study would be expected to result in a 0.2 degrees C temperature increase and do not therefore present a safety hazard to the retina. Copyright 2010, SLACK Incorporated.

Behavioral buffering of global warming in a cold-adapted lizard.

PubMed

Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

2016-07-01

Alpine lizards living in restricted areas might be particularly sensitive to climate change. We studied thermal biology of Iberolacerta cyreni in high mountains of central Spain. Our results suggest that I. cyreni is a cold-adapted thermal specialist and an effective thermoregulator. Among ectotherms, thermal specialists are more threatened by global warming than generalists. Alpine lizards have no chance to disperse to new suitable habitats. In addition, physiological plasticity is unlikely to keep pace with the expected rates of environmental warming. Thus, lizards might rely on their behavior in order to deal with ongoing climate warming. Plasticity of thermoregulatory behavior has been proposed to buffer the rise of environmental temperatures. Therefore, we studied the change in body and environmental temperatures, as well as their relationships, for I. cyreni between the 1980s and 2012. Air temperatures have increased more than 3.5°C and substrate temperatures have increased by 6°C in the habitat of I. cyreni over the last 25 years. However, body temperatures of lizards have increased less than 2°C in the same period, and the linear relationship between body and environmental temperatures remains similar. These results show that alpine lizards are buffering the potential impact of the increase in their environmental temperatures, most probably by means of their behavior. Body temperatures of I. cyreni are still cold enough to avoid any drop in fitness. Nonetheless, if warming continues, behavioral buffering might eventually become useless, as it would imply spending too much time in shelter, losing feeding, and mating opportunities. Eventually, if body temperature exceeds the thermal optimum in the near future, fitness would decrease abruptly.

Boreal and temperate trees show strong acclimation of respiration to warming.

PubMed

Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

2016-03-31

Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

Vertical structure of recent Arctic warming.

PubMed

Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla

2008-01-03

Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold season and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of warming that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce warming above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of warming can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification.

Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral.

PubMed

Caroselli, Erik; Falini, Giuseppe; Goffredo, Stefano; Dubinsky, Zvy; Levy, Oren

2015-01-01

Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography, and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13, 18, and 28°C), and two extreme temperatures expected for 2100 as a consequence of global warming (29 and 32°C). The indicators of photosynthetic performance analyzed (maximum and effective quantum yield) showed that maximum efficiency was reached at 20.0-21.6°C, slightly higher than the annual mean temperature in the field (18°C). Photosynthetic efficiency decreased from 20.0 to 13°C and even more strongly from 21.6 to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18 to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18 to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming.

Sea-Level Rise and Land Subsidence in Deltas: Estimating Future Flood Risk Through Integrated Natural and Human System Modeling

NASA Astrophysics Data System (ADS)

Tessler, Z. D.; Vorosmarty, C. J.

2016-12-01

Deltas are highly sensitive to local human activities, land subsidence, regional water management, global sea-level rise, and climate extremes. We present a new delta flood exposure and risk framework for estimating the sensitivity of deltas to relative sea-level rise. We have applied this framework to a set of global environmental, geophysical, and social indicators over 48 major river deltas to quantify how contemporary risks vary across delta systems. The risk modeling framework incorporates upstream sediment flux and coastal land subsidence models, global empirical estimates of contemporary storm surge exposure, and population distribution and growth. Future scenarios are used to test the impacts on coastal flood risk of upstream dam construction, coastal population growth, accelerated sea-level rise, and enhanced storm surge. Results suggest a wide range of outcomes across different delta systems within each scenario. Deltas in highly engineered watersheds (Mississippi, Rhine) exhibit less sensitivity to increased dams due to saturation of sediment retention effects, though planned or under-construction dams are expected to have a substantial impact in the Yangtze, Irrawaddy, and Magdalena deltas. Population growth and sea-level rise are expected to be the dominant drivers of increased human risk in most deltas, with important exceptions in several countries, particularly China, where population are forecast to contract over the next several decades.

On the direct impact of the CO2 concentration rise to the global warming

NASA Astrophysics Data System (ADS)

Laubereau, Alfred; Iglev, Hristo

2013-10-01

The growing amount of carbon dioxide in the atmosphere is often considered as the dominant factor for the global warming during the past decades. The noted correlation, however, does not answer the question about causality. In addition, the reported temperature data do not display a simple relationship between the monotonic concentration increase from 1880 to 2010 and the non-monotonic temperature rise during the same period. We have performed new measurements for optically thick samples of CO2 and investigate its role for the greenhouse effect on the basis of these spectroscopic data. Using simplified global models the warming of the surface is computed and a relatively modest effect is found, only: from the reported CO2 concentration rise in the atmosphere from 290 to 385 ppmv in 1880 to 2010 we derive a direct temperature rise of 0.26+/-0.01\\ \\text{K} . Including the simultaneous feedback effect of atmospheric water we still arrive at a minor CO2 contribution of less than 33% to the reported global warming of {\\sim}1.2\\ \\text{K} . It is suggested that other factors that are known to influence the greenhouse effect, e.g. air pollution by black carbon should be considered in more detail to fully understand the global temperature change.

Significant Climate Changes Caused by Soot Emitted From Rockets in the Stratosphere

NASA Astrophysics Data System (ADS)

Mills, M. J.; Ross, M.; Toohey, D. W.

2010-12-01

A new type of hydrocarbon rocket engine with a larger soot emission index than current kerosene rockets is expected to power a fleet of suborbital rockets for commercial and scientific purposes in coming decades. At projected launch rates, emissions from these rockets will create a persistent soot layer in the northern middle stratosphere that would disproportionally affect the Earth’s atmosphere and cryosphere. A global climate model predicts that thermal forcing in the rocket soot layer will cause significant changes in the global atmospheric circulation and distributions of ozone and temperature. Tropical ozone columns decline as much as 1%, while polar ozone columns increase by up to 6%. Polar surface temperatures rise one Kelvin regionally and polar summer sea ice fractions shrink between 5 - 15%. After 20 years of suborbital rocket fleet operation, globally averaged radiative forcing (RF) from rocket soot exceeds the RF from rocket CO_{2} by six orders of magnitude, but remains small, comparable to the global RF from aviation. The response of the climate system is surprising given the small forcing, and should be investigated further with different climate models.

Evolution of London penetration depth with scattering in single crystals of K1-xNaxFe2As2

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

Kim, H; Tanatar, M A; Liu, Yong

2014-05-01

London penetration depth, λ(T), was measured in single crystals of K1-xNaxFe2As2, x=0 and 0.07, down to temperatures of 50 mK, ~Tc/50. Isovalent substitution of Na for K significantly increases impurity scattering, with ρ(Tc) rising from 0.2 to 2.2 μΩ cm, and leads to a suppression of Tc from 3.5 to 2.8 K. At the same time, a close to T-linear Δλ(T) in pure samples changes to almost T2 in the substituted samples. The behavior never becomes exponential as expected for the accidental nodes, as opposed to T2 dependence in superconductors with symmetry imposed line nodes. The superfluid density in themore » full temperature range follows a simple clean and dirty d-wave dependence, for pure and substituted samples, respectively. This result contradicts suggestions of multiband scenarios with strongly different gap structure on four sheets of the Fermi surface.« less

An Improved Heat Budget Estimation Including Bottom Effects for General Ocean Circulation Models

NASA Technical Reports Server (NTRS)

Carder, Kendall; Warrior, Hari; Otis, Daniel; Chen, R. F.

2001-01-01

This paper studies the effects of the underwater light field on heat-budget calculations of general ocean circulation models for shallow waters. The presence of a bottom significantly alters the estimated heat budget in shallow waters, which affects the corresponding thermal stratification and hence modifies the circulation. Based on the data collected during the COBOP field experiment near the Bahamas, we have used a one-dimensional turbulence closure model to show the influence of the bottom reflection and absorption on the sea surface temperature field. The water depth has an almost one-to-one correlation with the temperature rise. Effects of varying the bottom albedo by replacing the sea grass bed with a coral sand bottom, also has an appreciable effect on the heat budget of the shallow regions. We believe that the differences in the heat budget for the shallow areas will have an influence on the local circulation processes and especially on the evaporative and long-wave heat losses for these areas. The ultimate effects on humidity and cloudiness of the region are expected to be significant as well.

Super Storm Desmond: a process-based assessment

NASA Astrophysics Data System (ADS)

Matthews, T.; Murphy, C.; McCarthy, G.; Broderick, C.; Wilby, R. L.

2018-01-01

‘Super’ Storm Desmond broke meteorological and hydrological records during a record warm year in the British-Irish Isles (BI). The severity of the storm may be a harbinger of expected changes to regional hydroclimate as global temperatures continue to rise. Here, we adopt a process-based approach to investigate the potency of Desmond, and explore the extent to which climate change may have been a contributory factor. Through an Eulerian assessment of water vapour flux we determine that Desmond was accompanied by an atmospheric river (AR) of severity unprecedented since at least 1979, on account of both high atmospheric humidity and high wind speeds. Lagrangian air-parcel tracking and moisture attribution techniques show that long-term warming of North Atlantic sea surface temperatures has significantly increased the chance of such high humidity in ARs in the vicinity of the BI. We conclude that, given exactly the same dynamical conditions associated with Desmond, the likelihood of such an intense AR has already increased by 25% due to long-term climate change. However, our analysis represents a first-order assessment, and further research is needed into the controls influencing AR dynamics.

Climate change and forest fires synergistically drive widespread melt events of the Greenland Ice Sheet.

PubMed

Keegan, Kaitlin M; Albert, Mary R; McConnell, Joseph R; Baker, Ian

2014-06-03

In July 2012, over 97% of the Greenland Ice Sheet experienced surface melt, the first widespread melt during the era of satellite remote sensing. Analysis of six Greenland shallow firn cores from the dry snow region confirms that the most recent prior widespread melt occurred in 1889. A firn core from the center of the ice sheet demonstrated that exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires reduced albedo below a critical threshold in the dry snow region, and caused the melting events in both 1889 and 2012. We use these data to project the frequency of widespread melt into the year 2100. Since Arctic temperatures and the frequency of forest fires are both expected to rise with climate change, our results suggest that widespread melt events on the Greenland Ice Sheet may begin to occur almost annually by the end of century. These events are likely to alter the surface mass balance of the ice sheet, leaving the surface susceptible to further melting.

Petit-spot as definitive evidence for partial melting in the asthenosphere caused by CO2

PubMed Central

Machida, Shiki; Kogiso, Tetsu; Hirano, Naoto

2017-01-01

The deep carbon cycle plays an important role on the chemical differentiation and physical properties of the Earth's mantle. Especially in the asthenosphere, seismic low-velocity and high electrical conductivity due to carbon dioxide (CO2)-induced partial melting are expected but not directly observed. Here we discuss the experimental results relevant to the genesis of primitive CO2-rich alkali magma forming petit-spot volcanoes at the deformation front of the outer rise of the northwestern Pacific plate. The results suggest that primitive melt last equilibrated with depleted peridotite at 1.8–2.1 GPa and 1,280–1,290 °C. Although the equilibration pressure corresponds to the pressure of the lower lithosphere, by considering an equilibration temperature higher than the solidus in the volatile–peridotite system along with the temperature of the lower lithosphere, we conclude that CO2-rich silicate melt is always produced in the asthenosphere. The melt subsequently ascends into and equilibrates with the lower lithosphere before eruption. PMID:28148927

Greenland Ice Sheet Surface Temperature, Melt, and Mass Loss: 2000-2006

NASA Technical Reports Server (NTRS)

Hall, Dorothy K.; Williams, Richard S., Jr.; Luthcke, Scott B.; DiGirolamo, Nocolo

2007-01-01

Extensive melt on the Greenland Ice Sheet has been documented by a variety of ground and satellite measurements in recent years. If the well-documented warming continues in the Arctic, melting of the Greenland Ice Sheet will likely accelerate, contributing to sea-level rise. Modeling studies indicate that an annual or summer temperature rise of 1 C on the ice sheet will increase melt by 20-50% therefore, surface temperature is one of the most important ice-sheet parameters to study for analysis of changes in the mass balance of the ice-sheet. The Greenland Ice Sheet contains enough water to produce a rise in eustatic sea level of up to 7.0 m if the ice were to melt completely. However, even small changes (centimeters) in sea level would cause important economic and societal consequences in the world's major coastal cities thus it is extremely important to monitor changes in the ice-sheet surface temperature and to ultimately quantify these changes in terms of amount of sea-level rise. We have compiled a high-resolution, daily time series of surface temperature of the Greenland Ice Sheet, using the I-km resolution, clear-sky land-surface temperature (LST) standard product from the Moderate-Resolution Imaging Spectroradiometer (MODIS), from 2000 - 2006. We also use Gravity Recovery and Climate Experiment (GRACE) data, averaged over 10-day periods, to measure change in mass of the ice sheet as it melt and snow accumulates. Surface temperature can be used to determine frequency of surface melt, timing of the start and the end of the melt season, and duration of melt. In conjunction with GRACE data, it can also be used to analyze timing of ice-sheet mass loss and gain.

Shifts in the seasonal distribution of deaths in Australia, 1968-2007

NASA Astrophysics Data System (ADS)

Bennett, Charmian M.; Dear, Keith B. G.; McMichael, Anthony J.

2014-07-01

Studies in temperate countries have shown that both hot weather in summer and cold weather in winter increase short-term (daily) mortality. The gradual warming, decade on decade, that Australia has experienced since the 1960s, might therefore be expected to have differentially affected mortality in the two seasons, and thus indicate an early impact of climate change on human health. Failure to detect such a signal would challenge the widespread assumption that the effect of weather on mortality implies a similar effect of a change from the present to projected future climate. We examine the ratio of summer to winter deaths against a background of rising average annual temperatures over four decades: the ratio has increased from 0.71 to 0.86 since 1968. The same trend, albeit of varying strength, is evident in all states of Australia, in four age groups (aged 55 years and above) and in both sexes. Analysis of cause-specific mortality suggests that the change has so far been driven more by reduced winter mortality than by increased summer mortality. Furthermore, comparisons of this seasonal mortality ratio calculated in the warmest subsets of seasons in each decade, with that calculated in the coldest seasons, show that particularly warm annual conditions, which mimic the expected temperatures of future climate change, increase the likelihood of higher ratios (approaching 1:1). Overall, our results indicate that gradual climate change, as well as short-term weather variations, affect patterns of mortality.

Impacts of ambient temperature on the burden of bacillary dysentery in urban and rural Hefei, China.

PubMed

Cheng, J; Xie, M Y; Zhao, K F; Wu, J J; Xu, Z W; Song, J; Zhao, D S; Li, K S; Wang, X; Yang, H H; Wen, L Y; Su, H; Tong, S L

2017-06-01

Bacillary dysentery continues to be a major health issue in developing countries and ambient temperature is a possible environmental determinant. However, evidence about the risk of bacillary dysentery attributable to ambient temperature under climate change scenarios is scarce. We examined the attributable fraction (AF) of temperature-related bacillary dysentery in urban and rural Hefei, China during 2006-2012 and projected its shifting pattern under climate change scenarios using a distributed lag non-linear model. The risk of bacillary dysentery increased with the temperature rise above a threshold (18·4 °C), and the temperature effects appeared to be acute. The proportion of bacillary dysentery attributable to hot temperatures was 18·74% (95 empirical confidence interval (eCI): 8·36-27·44%). Apparent difference of AF was observed between urban and rural areas, with AF varying from 26·87% (95% eCI 16·21-36·68%) in urban area to -1·90% (95 eCI -25·03 to 16·05%) in rural area. Under the climate change scenarios alone (1-4 °C rise), the AF from extreme hot temperatures (>31·2 °C) would rise greatly accompanied by the relatively stable AF from moderate hot temperatures (18·4-31·2 °C). If climate change proceeds, urban area may be more likely to suffer from rapidly increasing burden of disease from extreme hot temperatures in the absence of effective mitigation and adaptation strategies.

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

Bierlich, Christian; Gustafson, Gösta; Lönnblad, Leif

In models for hadron collisions based on string hadronization, the strings are usually treated as independent, allowing no interaction between the confined colour fields. In studies of nucleus collisions it has been suggested that strings close in space can fuse to form "colour ropes." Such ropes are expected to give more strange particles and baryons, which also has been suggested as a signal for plasma formation. Overlapping strings can also be expected in pp collisions, where usually no phase transition is expected. In particular at the high LHC energies the expected density of strings is quite high. To investigate possiblemore » effects of rope formation, we present a model in which strings are allowed to combine into higher multiplets, giving rise to increased production of baryons and strangeness, or recombine into singlet structures and vanish. Also a crude model for strings recombining into junction structures is considered, again giving rise to increased baryon production. The models are implemented in the DIPSY MC event generator, using PYTHIA8 for hadronization, and comparison to pp minimum bias data, reveals improvement in the description of identified particle spectra.« less

Effects of overlapping strings in pp collisions

DOE PAGES

Bierlich, Christian; Gustafson, Gösta; Lönnblad, Leif; ...

2015-03-26

In models for hadron collisions based on string hadronization, the strings are usually treated as independent, allowing no interaction between the confined colour fields. In studies of nucleus collisions it has been suggested that strings close in space can fuse to form "colour ropes." Such ropes are expected to give more strange particles and baryons, which also has been suggested as a signal for plasma formation. Overlapping strings can also be expected in pp collisions, where usually no phase transition is expected. In particular at the high LHC energies the expected density of strings is quite high. To investigate possiblemore » effects of rope formation, we present a model in which strings are allowed to combine into higher multiplets, giving rise to increased production of baryons and strangeness, or recombine into singlet structures and vanish. Also a crude model for strings recombining into junction structures is considered, again giving rise to increased baryon production. The models are implemented in the DIPSY MC event generator, using PYTHIA8 for hadronization, and comparison to pp minimum bias data, reveals improvement in the description of identified particle spectra.« less

Spatial distribution of unidirectional trends in temperature and temperature extremes in Pakistan

NASA Astrophysics Data System (ADS)

Khan, Najeebullah; Shahid, Shamsuddin; Ismail, Tarmizi bin; Wang, Xiao-Jun

2018-06-01

Pakistan is one of the most vulnerable countries of the world to temperature extremes due to its predominant arid climate and geographic location in the fast temperature rising zone. Spatial distribution of the trends in annual and seasonal temperatures and temperature extremes over Pakistan has been assessed in this study. The gauge-based gridded daily temperature data of Berkeley Earth Surface Temperature (BEST) having a spatial resolution of 1° × 1° was used for the assessment of trends over the period 1960-2013 using modified Mann-Kendall test (MMK), which can discriminate the multi-decadal oscillatory variations from secular trends. The results show an increase in the annual average of daily maximum and minimum temperatures in 92 and 99% area of Pakistan respectively at 95% level of confidence. The annual temperature is increasing faster in southern high-temperature region compared to other parts of the country. The minimum temperature is rising faster (0.17-0.37 °C/decade) compared to maximum temperature (0.17-0.29 °C/decade) and therefore declination of diurnal temperature range (DTR) (- 0.15 to - 0.08 °C/decade) in some regions. The annual numbers of both hot and cold days are increasing in whole Pakistan except in the northern sub-Himalayan region. Heat waves are on the rise, especially in the hot Sindh plains and the Southern coastal region, while the cold waves are becoming lesser in the northern cold region. Obtained results contradict with the findings of previous studies on temperature trends, which indicate the need for reassessment of climatic trends in Pakistan using the MMK test to understand the anthropogenic impacts of climate change.

Is the detection of accelerated sea level rise imminent?

DOE PAGES

Fasullo, J. T.; Nerem, R. S.; Hamlington, B.

2016-08-10

Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This maskingmore » arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption. As a result, a consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.« less

Is the detection of accelerated sea level rise imminent?

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

Fasullo, J. T.; Nerem, R. S.; Hamlington, B.

Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This maskingmore » arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption. As a result, a consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.« less

Special Issue: Response of Microbial Communities to Environmental Changes.

PubMed

Stingl, Ulrich

2018-03-30

Environmental issues such as eutrophication, ocean acidification, sea level rise, saltwater intrusion, increase in carbon dioxide levels, or rise of average global temperatures, among many others, are impacting and changing whole ecosystems [...].

Temperature sensitivity differences with depth and season between carbon, nitrogen, and phosphorus cycling enzyme activities in an ombrotrophic peatland system

NASA Astrophysics Data System (ADS)

Steinweg, J. M.; Kostka, J. E.; Hanson, P. J.; Schadt, C. W.

2017-12-01

Northern peatlands have large amounts of soil organic matter due to reduced decomposition. Breakdown of organic matter is initially mediated by extracellular enzymes, the activity of which may be controlled by temperature, moisture, and substrate availability, all of which vary seasonally throughout the year and with depth. In typical soils the majority of the microbial biomass and decomposition occurs within the top 30cm due to reduced organic matter inputs in the subsurface however peatlands by their very nature contain large amounts of organic matter throughout their depth profile. We hypothesized that potential enzyme activity would be greatest at the surface of the peat due to a larger microbial biomass compared to 40cm and 175cm below the surface and that temperature sensitivity would be greatest at the surface during winter but lowest during the summer due to high temperatures and enzyme efficiency. Peat samples were collected in February, July, and August 2012 from the DOE Spruce and Peatland Responses Under Climatic and Environmental Change project at Marcell Experimental Forest S1 bog. We measured potential activity of hydrolytic enzymes involved in three different nutrient cycles: beta-glucosidase (carbon), leucine amino peptidase (nitrogen), and phosphatase (phosphorus) at 15 temperature points ranging from 3°C to 65°C. Enzyme activity decreased with depth as expected but there was no concurrent change in activation energy (Ea). The reduction in enzyme activity with depth indicates a smaller pool which coincided with a decreased microbial biomass. Differences in enzyme activity with depth also mirrored the changes in peat composition from the acrotelm to the catotelm. Season did play a role in temperature sensitivity with Ea of β-glucosidase and phosphatase being the lowest in August as expected but leucine amino peptidase (a nitrogen acquiring enzyme) Ea was not influenced by season. As temperatures rise, especially in winter months, enzymatic carbon and phosphorus acquisition in the Marcell bog may increase whereas nitrogen acquisition would remain unchanged. The lack of temperature response for leucine amino peptidase has been measured in other systems but may be less of a concern in the Marcell bog due to low microbial biomass and enzymatic activity at depth and relatively low peat C:N ratios.

Weichselian permafrost depth in the Netherlands: a comprehensive uncertainty and sensitivity analysis

NASA Astrophysics Data System (ADS)

Govaerts, Joan; Beerten, Koen; ten Veen, Johan

2016-11-01

The Rupelian clay in the Netherlands is currently the subject of a feasibility study with respect to the storage of radioactive waste in the Netherlands (OPERA-project). Many features need to be considered in the assessment of the long-term evolution of the natural environment surrounding a geological waste disposal facility. One of these is permafrost development as it may have an impact on various components of the disposal system, including the natural environment (hydrogeology), the natural barrier (clay) and the engineered barrier. Determining how deep permafrost might develop in the future is desirable in order to properly address the possible impact on the various components. It is expected that periglacial conditions will reappear at some point during the next several hundred thousands of years, a typical time frame considered in geological waste disposal feasibility studies. In this study, the Weichselian glaciation is used as an analogue for future permafrost development. Permafrost depth modelling using a best estimate temperature curve of the Weichselian indicates that permafrost would reach depths between 155 and 195 m. Without imposing a climatic gradient over the country, deepest permafrost is expected in the south due to the lower geothermal heat flux and higher average sand content of the post-Rupelian overburden. Accounting for various sources of uncertainty, such as type and impact of vegetation, snow cover, surface temperature gradients across the country, possible errors in palaeoclimate reconstructions, porosity, lithology and geothermal heat flux, stochastic calculations point out that permafrost depth during the coldest stages of a glacial cycle such as the Weichselian, for any location in the Netherlands, would be 130-210 m at the 2σ level. In any case, permafrost would not reach depths greater than 270 m. The most sensitive parameters in permafrost development are the mean annual air temperatures and porosity, while the geothermal heat flux is the crucial parameter in permafrost degradation once temperatures start rising again.

Cost-Risk Trade-off of Solar Radiation Management and Mitigation under Probabilistic Information on Climate Sensitivity

NASA Astrophysics Data System (ADS)

Khabbazan, Mohammad Mohammadi; Roshan, Elnaz; Held, Hermann

2017-04-01

In principle solar radiation management (SRM) offers an option to ameliorate anthropogenic temperature rise. However we cannot expect it to simultaneously compensate for anthropogenic changes in further climate variables in a perfect manner. Here, we ask to what extent a proponent of the 2°C-temperature target would apply SRM in conjunction with mitigation in view of global or regional disparities in precipitation changes. We apply cost-risk analysis (CRA), which is a decision analytic framework that makes a trade-off between the expected welfare-loss from climate policy costs and the climate risks from transgressing a climate target. Here, in both global-scale and 'Giorgi'-regional-scale analyses, we evaluate the optimal mixture of SRM and mitigation under probabilistic information about climate sensitivity. To do so, we generalize CRA for the sake of including not only temperature risk, but also globally aggregated and regionally disaggregated precipitation risks. Social welfare is maximized for the following three valuation scenarios: temperature-risk-only, precipitation-risk-only, and equally weighted both-risks. For now, the Giorgi regions are treated by equal weight. We find that for regionally differentiated precipitation targets, the usage of SRM will be comparably more restricted. In the course of time, a cooling of up to 1.3°C can be attributed to SRM for the latter scenario and for a median climate sensitivity of 3°C (for a global target only, this number reduces by 0.5°C). Our results indicate that although SRM would almost completely substitute for mitigation in the globally aggregated analysis, it only saves 70% to 75% of the welfare-loss compared to a purely mitigation-based analysis (from economic costs and climate risks, approximately 4% in terms of BGE) when considering regional precipitation risks in precipitation-risk-only and both-risks scenarios. It remains to be shown how the inclusion of further risks or different regional weights would change that picture.

Chapter 1. Impacts of the oceans on climate change.

PubMed

Reid, Philip C; Fischer, Astrid C; Lewis-Brown, Emily; Meredith, Michael P; Sparrow, Mike; Andersson, Andreas J; Antia, Avan; Bates, Nicholas R; Bathmann, Ulrich; Beaugrand, Gregory; Brix, Holger; Dye, Stephen; Edwards, Martin; Furevik, Tore; Gangstø, Reidun; Hátún, Hjálmar; Hopcroft, Russell R; Kendall, Mike; Kasten, Sabine; Keeling, Ralph; Le Quéré, Corinne; Mackenzie, Fred T; Malin, Gill; Mauritzen, Cecilie; Olafsson, Jón; Paull, Charlie; Rignot, Eric; Shimada, Koji; Vogt, Meike; Wallace, Craig; Wang, Zhaomin; Washington, Richard

2009-01-01

The oceans play a key role in climate regulation especially in part buffering (neutralising) the effects of increasing levels of greenhouse gases in the atmosphere and rising global temperatures. This chapter examines how the regulatory processes performed by the oceans alter as a response to climate change and assesses the extent to which positive feedbacks from the ocean may exacerbate climate change. There is clear evidence for rapid change in the oceans. As the main heat store for the world there has been an accelerating change in sea temperatures over the last few decades, which has contributed to rising sea-level. The oceans are also the main store of carbon dioxide (CO2), and are estimated to have taken up approximately 40% of anthropogenic-sourced CO2 from the atmosphere since the beginning of the industrial revolution. A proportion of the carbon uptake is exported via the four ocean 'carbon pumps' (Solubility, Biological, Continental Shelf and Carbonate Counter) to the deep ocean reservoir. Increases in sea temperature and changing planktonic systems and ocean currents may lead to a reduction in the uptake of CO2 by the ocean; some evidence suggests a suppression of parts of the marine carbon sink is already underway. While the oceans have buffered climate change through the uptake of CO2 produced by fossil fuel burning this has already had an impact on ocean chemistry through ocean acidification and will continue to do so. Feedbacks to climate change from acidification may result from expected impacts on marine organisms (especially corals and calcareous plankton), ecosystems and biogeochemical cycles. The polar regions of the world are showing the most rapid responses to climate change. As a result of a strong ice-ocean influence, small changes in temperature, salinity and ice cover may trigger large and sudden changes in regional climate with potential downstream feedbacks to the climate of the rest of the world. A warming Arctic Ocean may lead to further releases of the potent greenhouse gas methane from hydrates and permafrost. The Southern Ocean plays a critical role in driving, modifying and regulating global climate change via the carbon cycle and through its impact on adjacent Antarctica. The Antarctic Peninsula has shown some of the most rapid rises in atmospheric and oceanic temperature in the world, with an associated retreat of the majority of glaciers. Parts of the West Antarctic ice sheet are deflating rapidly, very likely due to a change in the flux of oceanic heat to the undersides of the floating ice shelves. The final section on modelling feedbacks from the ocean to climate change identifies limitations and priorities for model development and associated observations. Considering the importance of the oceans to climate change and our limited understanding of climate-related ocean processes, our ability to measure the changes that are taking place are conspicuously inadequate. The chapter highlights the need for a comprehensive, adequately funded and globally extensive ocean observing system to be implemented and sustained as a high priority. Unless feedbacks from the oceans to climate change are adequately included in climate change models, it is possible that the mitigation actions needed to stabilise CO2 and limit temperature rise over the next century will be underestimated.

Vulnerability Reduction Needed to Maintain Current Burdens of Heat-Related Mortality in a Changing Climate-Magnitude and Determinants.

PubMed

Åström, Christofer; Åström, Daniel Oudin; Andersson, Camilla; Ebi, Kristie L; Forsberg, Bertil

2017-07-07

The health burden from heatwaves is expected to increase with rising global mean temperatures and more extreme heat events over the coming decades. Health-related effects from extreme heat are more common in elderly populations. The population of Europe is rapidly aging, which will increase the health effects of future temperatures. In this study, we estimate the magnitude of adaptation needed to lower vulnerability to heat in order to prevent an increase in heat-related deaths in the 2050s; this is the Adaptive Risk Reduction (ARR) needed. Temperature projections under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 from 18 climate models were coupled with gridded population data and exposure-response relationships from a European multi-city study on heat-related mortality. In the 2050s, the ARR for the general population is 53.5%, based on temperature projections under RCP 4.5. For the population above 65 years in Southern Europe, the ARR is projected to be 45.9% in a future with an unchanged climate and 74.7% with climate change under RCP 4.5. The ARRs were higher under RCP 8.5. Whichever emission scenario is followed or population projection assumed, Europe will need to adapt to a great degree to maintain heat-related mortality at present levels, which are themselves unacceptably high, posing an even greater challenge.

Vulnerability Reduction Needed to Maintain Current Burdens of Heat-Related Mortality in a Changing Climate—Magnitude and Determinants

PubMed Central

Åström, Christofer; Oudin Åström, Daniel; Andersson, Camilla; L. Ebi, Kristie; Forsberg, Bertil

2017-01-01

The health burden from heatwaves is expected to increase with rising global mean temperatures and more extreme heat events over the coming decades. Health-related effects from extreme heat are more common in elderly populations. The population of Europe is rapidly aging, which will increase the health effects of future temperatures. In this study, we estimate the magnitude of adaptation needed to lower vulnerability to heat in order to prevent an increase in heat-related deaths in the 2050s; this is the Adaptive Risk Reduction (ARR) needed. Temperature projections under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 from 18 climate models were coupled with gridded population data and exposure-response relationships from a European multi-city study on heat-related mortality. In the 2050s, the ARR for the general population is 53.5%, based on temperature projections under RCP 4.5. For the population above 65 years in Southern Europe, the ARR is projected to be 45.9% in a future with an unchanged climate and 74.7% with climate change under RCP 4.5. The ARRs were higher under RCP 8.5. Whichever emission scenario is followed or population projection assumed, Europe will need to adapt to a great degree to maintain heat-related mortality at present levels, which are themselves unacceptably high, posing an even greater challenge. PMID:28686197

Thermodynamic properties Ar films on the surface of a bundle of carbon nanotubes

NASA Astrophysics Data System (ADS)

Cole, Milton; Gatica, Silvina

2005-03-01

We employ canonical Monte Carlo simulations to explore the properties of an Argon film adsorbed on the external surface of a bundle of carbon nanotubes. The study is concerned primarily with three properties: specific heat, differential heat of adsorption, and Ar-Ar correlation functions. These measurable functions exhibit information about the dependence of film structure on coverage and temperature. Our results are intended to stimulate further experimental studies of this system and analogous systems involving other gases on nanotube bundles. One of the more interesting general results is that the specific heat is typically larger than might have been expected. Particularly remarkable outcome from the correlation function studies include the reduced longitudinal correlations in the groove and striped phases as T rises above 60 K. These results would be amenable to testing by diffraction experiments.

Running of featureful primordial power spectra

NASA Astrophysics Data System (ADS)

Gariazzo, Stefano; Mena, Olga; Miralles, Victor; Ramírez, Héctor; Boubekeur, Lotfi

2017-06-01

Current measurements of the temperature and polarization anisotropy power spectra of the cosmic microwave background (CMB) seem to indicate that the naive expectation for the slow-roll hierarchy within the most simple inflationary paradigm may not be respected in nature. We show that a primordial power spectrum with localized features could in principle give rise to the observed slow-roll anarchy when fitted to a featureless power spectrum. From a model comparison perspective, and assuming that nature has chosen a featureless primordial power spectrum, we find that, while with mock Planck data there is only weak evidence against a model with localized features, upcoming CMB missions may provide compelling evidence against such a nonstandard primordial power spectrum. This evidence could be reinforced if a featureless primordial power spectrum is independently confirmed from bispectrum and/or galaxy clustering measurements.

Multidecadal increase in North Atlantic coccolithophores and the potential role of rising CO2

NASA Astrophysics Data System (ADS)

Rivero-Calle, Sara; Gnanadesikan, Anand; Del Castillo, Carlos E.; Balch, William M.; Guikema, Seth D.

2015-12-01

As anthropogenic carbon dioxide (CO2) emissions acidify the oceans, calcifiers generally are expected to be negatively affected. However, using data from the Continuous Plankton Recorder, we show that coccolithophore occurrence in the North Atlantic increased from ~2 to more than 20% from 1965 through 2010. We used random forest models to examine more than 20 possible environmental drivers of this change, finding that CO2 and the Atlantic Multidecadal Oscillation were the best predictors, leading us to hypothesize that higher CO2 levels might be encouraging growth. A compilation of 41 independent laboratory studies supports our hypothesis. Our study shows a long-term basin-scale increase in coccolithophores and suggests that increasing CO2 and temperature have accelerated the growth of a phytoplankton group that is important for carbon cycling.

Feasibility of water injection into the turbine coolant to permit gas turbine contingency power for helicopter application

NASA Technical Reports Server (NTRS)

Vanfossen, G. J.

1983-01-01

A system which would allow a substantially increased output from a turboshaft engine for brief periods in emergency situations with little or no loss of turbine stress rupture life is proposed and studied analytically. The increased engine output is obtained by overtemperaturing the turbine; however, the temperature of the compressor bleed air used for hot section cooling is lowered by injecting and evaporating water. This decrease in cooling air temperature can offset the effect of increased gas temperature and increased shaft speed and thus keep turbine blade stress rupture life constant. The analysis utilized the NASA-Navy-Engine-Program or NNEP computer code to model the turboshaft engine in both design and off-design modes. This report is concerned with the effect of the proposed method of power augmentation on the engine cycle and turbine components. A simple cycle turboshaft engine with a 16:1 pressure ratio and a 1533 K (2760 R) turbine inlet temperature operating at sea level static conditions was studied to determine the possible power increase and the effect on turbine stress rupture life that could be expected using the proposed emergency cooling scheme. The analysis showed a 54 percent increse in output power can be achieved with no loss in gas generator turbine stress rupture life. A 231 K (415 F) rise in turbine inlet temperature is required for this level of augmentation. The required water flow rate was found to be .0109 kg water per kg of engine air flow.

Global climate change and sea level rise: potential losses of intertidal habitat for shorebirds

Treesearch

H. Galbraith; R. Jones; R. Park; J. Clough; S. Herrod-Julius; B. Harrington; G. Page

2005-01-01

Global warming is expected to result in an acceleration of current rates of sea level rise, inundating many low-lying coastal and intertidal areas. This could have important implications for organisms that depend on these sites, including shorebirds that rely on them for foraging habitat during their migrations and in winter. We modeled the potential changes in the...

Effects of rising temperature on the viability of an important sea turtle rookery

NASA Astrophysics Data System (ADS)

Laloë, Jacques-Olivier; Cozens, Jacquie; Renom, Berta; Taxonera, Albert; Hays, Graeme C.

2014-06-01

A warming world poses challenges for species with temperature-dependent sex determination, including sea turtles, for which warmer incubation temperatures produce female hatchlings. We combined in situ sand temperature measurements with air temperature records since 1850 and predicted warming scenarios from the Intergovernmental Panel on Climate Change to derive 250-year time series of incubation temperatures, hatchling sex ratios, and operational sex ratios for one of the largest sea turtles rookeries globally (Cape Verde Islands, Atlantic). We estimate that light-coloured beaches currently produce 70.10% females whereas dark-coloured beaches produce 93.46% females. Despite increasingly female skewed sex ratios, entire feminization of this population is not imminent. Rising temperatures increase the number of breeding females and hence the natural rate of population growth. Predicting climate warming impacts across hatchlings, male-female breeding ratios and nesting numbers provides a holistic approach to assessing the conservation concerns for sea turtles in a warming world.

The circadian rhythm of core temperature: origin and some implications for exercise performance.

PubMed

Waterhouse, Jim; Drust, Barry; Weinert, Dietmar; Edwards, Benjamin; Gregson, Warren; Atkinson, Greg; Kao, Shaoyuan; Aizawa, Seika; Reilly, Thomas

2005-01-01

This review first examines reliable and convenient ways of measuring core temperature for studying the circadian rhythm, concluding that measurements of rectal and gut temperature fulfil these requirements, but that insulated axilla temperature does not. The origin of the circadian rhythm of core temperature is mainly due to circadian changes in the rate of loss of heat through the extremities, mediated by vasodilatation of the cutaneous vasculature. Difficulties arise when the rhythm of core temperature is used as a marker of the body clock, since it is also affected by the sleep-wake cycle. This masking effect can be overcome directly by constant routines and indirectly by "purification" methods, several of which are described. Evidence supports the value of purification methods to act as a substitute when constant routines cannot be performed. Since many of the mechanisms that rise to the circadian rhythm of core temperature are the same as those that occur during thermoregulation in exercise, there is an interaction between the two. This interaction is manifest in the initial response to spontaneous activity and to mild exercise, body temperature rising more quickly and thermoregulatory reflexes being recruited less quickly around the trough and rising phase of the resting temperature rhythm, in comparison with the peak and falling phase. There are also implications for athletes, who need to exercise maximally and with minimal risk of muscle injury or heat exhaustion in a variety of ambient temperatures and at different times of the day. Understanding the circadian rhythm of core temperature may reduce potential hazards due to the time of day when exercise is performed.

Conductivity Rise During Irreversible Electroporation: True Permeabilization or Heat?

PubMed

Ruarus, Alette H; Vroomen, Laurien G P H; Puijk, Robbert S; Scheffer, Hester J; Faes, Theo J C; Meijerink, Martijn R

2018-04-23

Irreversible electroporation (IRE) induces apoptosis with high-voltage electric pulses. Although the working mechanism is non-thermal, development of secondary Joule heating occurs. This study investigated whether the observed conductivity rise during IRE is caused by increased cellular permeabilization or heat development. IRE was performed in a gelatin tissue phantom, in potato tubers, and in 30 patients with unresectable colorectal liver metastases (CRLM). Continuous versus sequential pulsing protocols (10-90 vs. 10-30-30-30) were assessed. Temperature was measured using fiber-optic probes. After temperature had returned to baseline, 100 additional pulses were delivered. The primary technique efficacy of the treated CRLM was compared to the periprocedural current rise. Seven patients received ten additional pulses after a 10-min cool-down period. Temperature and current rise was higher for the continuous pulsing protocol (medians, gel: 13.05 vs. 9.55 °C and 9 amperes (A) vs. 7A; potato: 12.70 vs. 10.53 °C and 6.0A vs. 6.5A). After cooling-down, current returned to baseline in the gel phantom and near baseline values (Δ2A with continuous- and Δ5A with sequential pulsing) in the potato tubers. The current declined after cooling-down in all seven patients with CRLM, although baseline values were not reached. There was a positive correlation between current rise and primary technique efficacy (p = 0.02); however, the previously reported current increase threshold of 12-15A was reached in 13%. The observed conductivity rise during IRE is caused by both cellular permeabilization and heat development. Although a correlation between current rise and efficacy exists, the current increase threshold seems unfeasible for CRLM.

Drilling in bone: modeling heat generation and temperature distribution.

PubMed

Davidson, Sean R; James, David F

2003-06-01

Thermo-mechanical equations were developed from machining theory to predict heat generation due to drilling and were coupled with a heat transfer FEM simulation to predict the temperature rise and thermal injury in bone during a drilling operation. The rotational speed, feed rate, drill geometry and bone material properties were varied in a parametric analysis to determine the importance of each on temperature rise and therefore on thermal damage. It was found that drill speed, feed rate and drill diameter had the most significant thermal impact while changes in drill helix angle, point angle and bone thermal properties had relatively little effect.

Temperature in lowland Danish streams: contemporary patterns, empirical models and future scenarios

NASA Astrophysics Data System (ADS)

Lagergaard Pedersen, Niels; Sand-Jensen, Kaj

2007-01-01

Continuous temperature measurements at 11 stream sites in small lowland streams of North Zealand, Denmark over a year showed much higher summer temperatures and lower winter temperatures along the course of the stream with artificial lakes than in the stream without lakes. The influence of lakes was even more prominent in the comparisons of colder lake inlets and warmer outlets and led to the decline of cold-water and oxygen-demanding brown trout. Seasonal and daily temperature variations were, as anticipated, dampened by forest cover, groundwater input, input from sewage plants and high downstream discharges. Seasonal variations in daily water temperature could be predicted with high accuracy at all sites by a linear air-water regression model (r2: 0.903-0.947). The predictions improved in all instances (r2: 0.927-0.964) by a non-linear logistic regression according to which water temperatures do not fall below freezing and they increase less steeply than air temperatures at high temperatures because of enhanced heat loss from the stream by evaporation and back radiation. The predictions improved slightly (r2: 0.933-0.969) by a multiple regression model which, in addition to air temperature as the main predictor, included solar radiation at un-shaded sites, relative humidity, precipitation and discharge. Application of the non-linear logistic model for a warming scenario of 4-5 °C higher air temperatures in Denmark in 2070-2100 yielded predictions of temperatures rising 1.6-3.0 °C during winter and summer and 4.4-6.0 °C during spring in un-shaded streams with low groundwater input. Groundwater-fed springs are expected to follow the increase of mean air temperatures for the region. Great caution should be exercised in these temperature projections because global and regional climate scenarios remain open to discussion. Copyright

The costs of keeping cool in a warming world: implications of high temperatures for foraging, thermoregulation and body condition of an arid-zone bird.

PubMed

du Plessis, Katherine L; Martin, Rowan O; Hockey, Philip A R; Cunningham, Susan J; Ridley, Amanda R

2012-10-01

Recent mass mortalities of bats, birds and even humans highlight the substantial threats that rising global temperatures pose for endotherms. Although less dramatic, sublethal fitness costs of high temperatures may be considerable and result in changing population demographics. Endothermic animals exposed to high environmental temperatures can adjust their behaviour (e.g. reducing activity) or physiology (e.g. elevating rates of evaporative water loss) to maintain body temperatures within tolerable limits. The fitness consequences of these adjustments, in terms of the ability to balance water and energy budgets and therefore maintain body condition, are poorly known. We investigated the effects of daily maximum temperature on foraging and thermoregulatory behaviour as well as maintenance of body condition in a wild, habituated population of Southern Pied Babblers Turdoides bicolor. These birds inhabit a hot, arid area of southern Africa where they commonly experience environmental temperatures exceeding optimal body temperatures. Repeated measurements of individual behaviour and body mass were taken across days varying in maximum air temperature. Contrary to expectations, foraging effort was unaffected by daily maximum temperature. Foraging efficiency, however, was lower on hotter days and this was reflected in a drop in body mass on hotter days. When maximum air temperatures exceeded 35.5 °C, individuals no longer gained sufficient weight to counter typical overnight weight loss. This reduction in foraging efficiency is likely driven, in part, by a trade-off with the need to engage in heat-dissipation behaviours. When we controlled for temperature, individuals that actively dissipated heat while continuing to forage experienced a dramatic decrease in their foraging efficiency. This study demonstrates the value of investigations of temperature-dependent behaviour in the context of impacts on body condition, and suggests that increasingly high temperatures will have negative implications for the fitness of these arid-zone birds. © 2012 Blackwell Publishing Ltd.

The Higgs boson can delay reheating after inflation

NASA Astrophysics Data System (ADS)

Freese, Katherine; Sfakianakis, Evangelos I.; Stengel, Patrick; Visinelli, Luca

2018-05-01

The Standard Model Higgs boson, which has previously been shown to develop an effective vacuum expectation value during inflation, can give rise to large particle masses during inflation and reheating, leading to temporary blocking of the reheating process and a lower reheat temperature after inflation. We study the effects on the multiple stages of reheating: resonant particle production (preheating) as well as perturbative decays from coherent oscillations of the inflaton field. Specifically, we study both the cases of the inflaton coupling to Standard Model fermions through Yukawa interactions as well as to Abelian gauge fields through a Chern-Simons term. We find that, in the case of perturbative inflaton decay to SM fermions, reheating can be delayed due to Higgs blocking and the reheat temperature can decrease by up to an order of magnitude. In the case of gauge-reheating, Higgs-generated masses of the gauge fields can suppress preheating even for large inflaton-gauge couplings. In extreme cases, preheating can be shut down completely and must be substituted by perturbative decay as the dominant reheating channel. Finally, we discuss the distribution of reheat temperatures in different Hubble patches, arising from the stochastic nature of the Higgs VEV during inflation and its implications for the generation of both adiabatic and isocurvature fluctuations.

Stimulation research on the measurement of the IRW pneumatic thermal radiation

NASA Astrophysics Data System (ADS)

Wei, Yifang; Liu, Xiaohua; Liu, Ming; Dong, Liquan; Zhao, Yuejin

2018-01-01

When an aircraft flies at a hypersonic speed within the atmosphere, the temperature of the infrared window (IRW) on the aircraft will rise rapidly due to the high-speed incoming flow will produce a severe aerodynamic heating to its optical detection window. The infrared (IR) radiation of the high-temperature gas and optical window will generate severe pneumatic thermal radiation effect upon the detection system, with the performance of the IR detector possibly being reduced or even destroyed. To evaluate the influence on the target imaging made by the IRW radiation, the experiment on the basis of building a simulating model is conducted by the means of ray tracing so that the accurate transmittance of the IRW can be observed under the different temperature. And then the radiation distribution of the thermal radiation on the detector generated by the IRW radiation noise and target signal can finally be obtained. This paper also records the different parameters in the detection system being set in the experiment, and analyzes the different influences brought by various factors to the Signal to Noise Ratio (SNR). It is also expected that it will provide a data reference to the following research of radiation noise suppression and design of IR detection system.

Tuning the onset of ferromagnetism in heterogeneous bimetallic nanoparticles by gas phase doping

NASA Astrophysics Data System (ADS)

Bohra, Murtaza; Grammatikopoulos, Panagiotis; Singh, Vidyadhar; Zhao, Junlei; Toulkeridou, Evropi; Steinhauer, Stephan; Kioseoglou, Joseph; Bobo, Jean-François; Nordlund, Kai; Djurabekova, Flyura; Sowwan, Mukhles

2017-11-01

In the nanoregime, chemical species can reorganize in ways not predicted by their equilibrium bulk behavior. Here, we engineer Ni-Cr nanoalloys at the magnetic end of their compositional range (i.e., 0-15 at. % Cr), and we investigate the effect of Cr incorporation on their structural stability and resultant magnetic ordering. To ensure their stoichiometric compositions, the nanoalloys are grown by cluster beam deposition, a method that allows one-step, chemical-free fabrication of bimetallic nanoparticles. While full Cr segregation toward nanoparticle surfaces is thermodynamically expected for low Cr concentrations, metastability occurs as the Cr dopant level increases in the form of residual Cr in the core region, yielding desirable magnetic properties in a compensatory manner. Using nudged elastic band calculations, residual Cr in the core is explained based on modifications in the local environment of individual Cr atoms. The resultant competition between ferromagnetic and antiferromagnetic ordering gives rise to a wide assortment of interesting phenomena, such as a cluster-glass ground state at very low temperatures and an increase in Curie temperature values. We emphasize the importance of obtaining the commonly elusive magnetic nanophase diagram for M -Cr (M =Fe , Co, and Ni) nanoalloys, and we propose an efficient single-parameter method of tuning the Curie temperature for various technological applications.

Low temperature electroweak phase transition in the Standard Model with hidden scale invariance

NASA Astrophysics Data System (ADS)

Arunasalam, Suntharan; Kobakhidze, Archil; Lagger, Cyril; Liang, Shelley; Zhou, Albert

2018-01-01

We discuss a cosmological phase transition within the Standard Model which incorporates spontaneously broken scale invariance as a low-energy theory. In addition to the Standard Model fields, the minimal model involves a light dilaton, which acquires a large vacuum expectation value (VEV) through the mechanism of dimensional transmutation. Under the assumption of the cancellation of the vacuum energy, the dilaton develops a very small mass at 2-loop order. As a result, a flat direction is present in the classical dilaton-Higgs potential at zero temperature while the quantum potential admits two (almost) degenerate local minima with unbroken and broken electroweak symmetry. We found that the cosmological electroweak phase transition in this model can only be triggered by a QCD chiral symmetry breaking phase transition at low temperatures, T ≲ 132 MeV. Furthermore, unlike the standard case, the universe settles into the chiral symmetry breaking vacuum via a first-order phase transition which gives rise to a stochastic gravitational background with a peak frequency ∼10-8 Hz as well as triggers the production of approximately solar mass primordial black holes. The observation of these signatures of cosmological phase transitions together with the detection of a light dilaton would provide a strong hint of the fundamental role of scale invariance in particle physics.

Nuclear winter - Global consequences of multiple nuclear explosions

NASA Technical Reports Server (NTRS)

Turco, R. P.; Toon, O. B.; Ackerman, T. P.; Pollack, J. B.; Sagan, C.

1983-01-01

The results of a computerized simulation of the potential global environmental effects of dust and smoke clouds that would be generated by a nuclear war are presented. Short term effects of blast, fire, and radiation are neglected in the series of physical models that include a nuclear war scenario, a particle microphysics model, and a radiative convective model. Account is taken of the altitude-dependent dust, smoke, radioactivity, and NO(x) injections, the temporal evolution of dust and smoke clouds, land and ocean environments, and temperature contrasts. A nuclear exchange would produce thousands of individual smoke and dust clouds rising up to 30 km altitude in the midlatitudes. The smoke, dust, and radioactive debris would cover the entire midlatitudes within 1-2 weeks. The smoke would arise from conflagrations of forests, suburbs, and urban areas. Obscuration of sunlight would induce subfreezing temperatures for several months, disruption of the global circulation patterns, and the arrival of a nuclear winter, followed and accompanied by radioactive fallout, pyrogenic air pollution, and UV-B flux enhancements. It is estimated that a total of only 100 Mtons would be sufficient to plunge the Northern Hemisphere summer to subfreezing temperatures lasting months. Since the probable exchange in a nuclear war would exceed 5000 Mtons, it is expected that many species, including humans, may not survive the war.

Direct observation of resistive heating at graphene wrinkles and grain boundaries

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

Grosse, Kyle L.; Dorgan, Vincent E.; Estrada, David

We directly measure the nanometer-scale temperature rise at wrinkles and grain boundaries (GBs) in functioning graphene devices by scanning Joule expansion microscopy with 50 nm spatial and 0.2K temperature resolution. We observe a small temperature increase at select wrinkles and a large (100 K) temperature increase at GBs between coalesced hexagonal grains. Comparisons of measurements with device simulations estimate the GB resistivity (8 150 X lm) among the lowest reported for graphene grown by chemical vapor deposition. An analytical model is developed, showing that GBs can experience highly localized resistive heating and temperature rise, most likely affecting the reliability ofmore » graphene devices. Our studies provide an unprecedented view of thermal effects surrounding nanoscale defects in nanomaterials such as graphene.« less

Impacts of Rising Air Temperatures and Emissions Mitigation on Electricity Demand and Supply in the United States. A Multi-Model Comparison

DOE PAGES

McFarland, James; Zhou, Yuyu; Clarke, Leon; ...

2015-06-10

The electric power sector both affects and is affected by climate change. Numerous studies highlight the potential of the power sector to reduce greenhouse gas emissions. Fewer studies have explored the physical impacts of climate change on the power sector. Our present analysis examines how projected rising temperatures affect the demand for and supply of electricity. We apply a common set of temperature projections to three well-known electric sector models in the United States: the US version of the Global Change Assessment Model (GCAM-USA), the Regional Electricity Deployment System model (ReEDS), and the Integrated Planning Model (IPM®). Incorporating the effectsmore » of rising temperatures from a control scenario without emission mitigation into the models raises electricity demand by 1.6 to 6.5 % in 2050 with similar changes in emissions. Moreover, the increase in system costs in the reference scenario to meet this additional demand is comparable to the change in system costs associated with decreasing power sector emissions by approximately 50 % in 2050. This result underscores the importance of adequately incorporating the effects of long-run temperature change in climate policy analysis.« less

Simulation of chain of quenches on toroidal HTS-SMES taking account of thermal and electromagnetic characteristics

NASA Astrophysics Data System (ADS)

Oga, Y.; Noguchi, S.; Igarashi, H.

When a temperature rise occurs at a local area inside a coil of toroidal HTS-SMES by any reason, a temperature hotspot which results in a thermal runaway appears at the local area. Subsequently, after appearing the local normal zone in the HTS coil, the transport current of the HTS coil decrease since the resistance of HTS coil appears and the current partially flows into a parallel-connecting shunt resistance. However, if the transport current of the normal-transitioned HTS coil is hardly changed, the temperature on the hotspot would rise more and then the normal zone would spread rapidly. It may cause a serious accident due to high stored energy. Therefore, using the numerical simulation, we have investigated the behaviors of the coil current, the critical current, and the temperature in the superconducting element coils of HTS-SMES. Consequently, the temperature of the superconducting element coils rises up extremely when a large heat is generated at a certain area of one of them by any reason. Moreover, there is a possibility that the shunt resister hardly functions for protection since the coil is burned out due to high inductances and low resistance of the superconducting element coil.

Community health centers tackle rising demands and expectations.

PubMed

Hurley, Robert; Felland, Laurie; Lauer, Johanna

2007-12-01

As key providers of preventive and primary care for underserved people, including the uninsured, community health centers (CHCs) are the backbone of the U.S. health care safety net. Despite significant federal funding increases, community health centers are struggling to meet rising demand for care, particularly for specialty medical, dental and mental health services, according to findings from the Center for Studying Health System Change's (HSC) 2007 site visits to 12 nationally representative metropolitan communities. Health centers are responding to these pressures by expanding capacity and adding services but confront staffing, resource and other constraints. At the same time, CHCs are facing other demands, including increased quality reporting expectations, addressing racial and ethnic disparities, developing electronic medical records, and preparing for public health emergencies.

SU-E-I-45: Measurement of CT Dose to An HDPE Phantom Using Calorimetry: A Feasibility Study.

PubMed

Chen-Mayer, H; Tosh, R; Bateman, F; Zimmerman, B

2012-06-01

Radiation dose in CT is traditionally evaluated using an ionization chamber calibrated in terms of air kerma in a phantom of specific dimensions. The radiation absorbed dose, J/kg, can also be realized directly by measuring the temperature rise in the medium. We investigate using this primary method to determine the CT dose at a point (a few mm), using the recently proposed (APMM TG220) high density polyethylene (HDPE) phantom as a medium. The calorimeter detection scheme is adapted from the second generation NIST water calorimeter using sensitive thermistors in a Wheatstone bridge powered by a lock-in amplifier. The temperature sensitivity is about 3 microK. The expected temperature rise in PE is about 0.6 mK per Gy. The thermistor sensors were placed inside a 26 cm dia. × 10 cm HDPE phantom. Two preliminary tests were made: at a linear accelerator with a 6 MV photon beam, and at a 16-slice CT scanner with a 120 kV beam, each with the thermal sensor and with a calibrated ionization chamber. The 6 MV photon beam with 10 on/off cycles at 60 s each yielded the (uncorrected) run-to-run average dose of 3.06 Gy per cycle (sdm 0.3%), about 8% higher than the Result from the ionization chamber (calibrated in terms of absorbed to water). The CT measurements were also made in the middle section of the TG200 30 cm phantom. Twenty consecutive axial scans at 250 mA, which delivers a nominal accumulated dose (CTDIvol) of 705 mGy in 50 s at three axial and three radial locations were measured. The accumulated dose measured by the ionization chamber at the center of the smaller phantom was 347 mGy. The calorimeter data show qualitative tracking of the chamber measurements. Detailed thermal and electrical analysis of the system are planned to obtain quantitative results. © 2012 American Association of Physicists in Medicine.

TRPV1 deletion exacerbates hyperthermic seizures in an age-dependent manner in mice.

PubMed

Barrett, Karlene T; Wilson, Richard J A; Scantlebury, Morris H

2016-12-01

Febrile seizures (FS) are the most common seizure disorder to affect children. Although there is mounting evidence to support that FS occur when children have fever-induced hyperventilation leading to respiratory alkalosis, the underlying mechanisms of hyperthermia-induced hyperventilation and links to FS remain poorly understood. As transient receptor potential vanilloid-1 (TRPV1) receptors are heat-sensitive, play an important role in adult thermoregulation and modulate respiratory chemoreceptors, we hypothesize that TRPV1 activation is important for hyperthermia-induced hyperventilation leading to respiratory alkalosis and decreased FS thresholds, and consequently, TRPV1 KO mice will be relatively protected from hyperthermic seizures. To test our hypothesis we subjected postnatal (P) day 8-20 TRPV1 KO and C57BL/6 control mice to heated dry air. Seizure threshold temperature, latency and the rate of rise of body temperature during hyperthermia were assessed. At ages where differences in seizure thresholds were identified, head-out plethysmography was used to assess breathing and the rate of expired CO 2 in response to hyperthermia, to determine if the changes in seizure thresholds were related to respiratory alkalosis. Paradoxically, we observed a pro-convulsant effect of TRPV1 deletion (∼4min decrease in seizure latency), and increased ventilation in response to hyperthermia in TRPV1 KO compared to control mice at P20. This pro-convulsant effect of TRPV1 absence was not associated with an increased rate of expired CO 2 , however, these mice had a more rapid rise in body temperature following exposure to hyperthermia than controls, and the expected linear relationship between body weight and seizure latency was absent. Based on these findings, we conclude that deletion of the TRPV1 receptor prevents reduction in hyperthermic seizure susceptibility in older mouse pups, via a mechanism that is independent of hyperthermia-induced respiratory alkalosis, but possibly involves impaired development of thermoregulatory mechanisms, although at present the mechanism remain unknown. Copyright © 2016 Elsevier B.V. All rights reserved.

Canopy warming caused photosynthetic acclimation and reduced seed yield in maize grown at ambient and elevated [CO2 ].

PubMed

Ruiz-Vera, Ursula M; Siebers, Matthew H; Drag, David W; Ort, Donald R; Bernacchi, Carl J

2015-11-01

Rising atmospheric CO2 concentration ([CO2 ]) and attendant increases in growing season temperature are expected to be the most important global change factors impacting production agriculture. Although maize is the most highly produced crop worldwide, few studies have evaluated the interactive effects of elevated [CO2 ] and temperature on its photosynthetic physiology, agronomic traits or biomass, and seed yield under open field conditions. This study investigates the effects of rising [CO2 ] and warmer temperature, independently and in combination, on maize grown in the field throughout a full growing season. Free-air CO2 enrichment (FACE) technology was used to target atmospheric [CO2 ] to 200 μmol mol(-1) above ambient [CO2 ] and infrared heaters to target a plant canopy increase of 3.5 °C, with actual season mean heating of ~2.7 °C, mimicking conditions predicted by the second half of this century. Photosynthetic gas-exchange parameters, leaf nitrogen and carbon content, leaf water potential components, and developmental measurements were collected throughout the season, and biomass and yield were measured at the end of the growing season. As predicted for a C4 plant, elevated [CO2 ] did not stimulate photosynthesis, biomass, or yield. Canopy warming caused a large shift in aboveground allocation by stimulating season-long vegetative biomass and decreasing reproductive biomass accumulation at both CO2 concentrations, resulting in decreased harvest index. Warming caused a reduction in photosynthesis due to down-regulation of photosynthetic biochemical parameters and the decrease in the electron transport rate. The reduction in seed yield with warming was driven by reduced photosynthetic capacity and by a shift in aboveground carbon allocation away from reproduction. This field study portends that future warming will reduce yield in maize, and this will not be mitigated by higher atmospheric [CO2 ] unless appropriate adaptation traits can be introduced into future cultivars. © 2015 John Wiley & Sons Ltd.

An Exploration of the Notion of the "Good Enough School"

ERIC Educational Resources Information Center

James, Chris; Oplatka, Izhar

2015-01-01

In many countries, expectations of schools are very high and rising, with increasingly serious consequences for schools if those expectations are not met. It is as if only "perfect schools" will suffice--only then will all those with an interest in schools be satisfied. In this article, we argue that schools cannot be perfect and that…

Improving Students Soft Skills Using Thinking Process Profile Based on Personality Types

ERIC Educational Resources Information Center

Sunarto, M. J. Dewiyani

2015-01-01

The challenge in education field these days rises as the cause of society's expectation for higher education. This increasingly complex expectation demands that higher education prepares the students to gain integrity. Higher education provides not only hard skills for the student, but also soft skills. By observing the hard skills side, in the…

Expectations Rise for Higher Education in China as Reform Temper Begins to Take Hold.

ERIC Educational Resources Information Center

Jacobson, Robert L.

1987-01-01

China's national leadership is committed to a vast upgrading of education, and the pervasive spirit of reform in economics and politics is leading to higher expectations of higher education. Reforms are targeted in the system's structure, deemphasis on specialization, new emphasis on applied science, and faculty qualifications and productivity.…

Meth math: modeling temperature responses to methamphetamine.

PubMed

Molkov, Yaroslav I; Zaretskaia, Maria V; Zaretsky, Dmitry V

2014-04-15

Methamphetamine (Meth) can evoke extreme hyperthermia, which correlates with neurotoxicity and death in laboratory animals and humans. The objective of this study was to uncover the mechanisms of a complex dose dependence of temperature responses to Meth by mathematical modeling of the neuronal circuitry. On the basis of previous studies, we composed an artificial neural network with the core comprising three sequentially connected nodes: excitatory, medullary, and sympathetic preganglionic neuronal (SPN). Meth directly stimulated the excitatory node, an inhibitory drive targeted the medullary node, and, in high doses, an additional excitatory drive affected the SPN node. All model parameters (weights of connections, sensitivities, and time constants) were subject to fitting experimental time series of temperature responses to 1, 3, 5, and 10 mg/kg Meth. Modeling suggested that the temperature response to the lowest dose of Meth, which caused an immediate and short hyperthermia, involves neuronal excitation at a supramedullary level. The delay in response after the intermediate doses of Meth is a result of neuronal inhibition at the medullary level. Finally, the rapid and robust increase in body temperature induced by the highest dose of Meth involves activation of high-dose excitatory drive. The impairment in the inhibitory mechanism can provoke a life-threatening temperature rise and makes it a plausible cause of fatal hyperthermia in Meth users. We expect that studying putative neuronal sites of Meth action and the neuromediators involved in a detailed model of this system may lead to more effective strategies for prevention and treatment of hyperthermia induced by amphetamine-like stimulants.

Meth math: modeling temperature responses to methamphetamine

PubMed Central

Molkov, Yaroslav I.; Zaretskaia, Maria V.

2014-01-01

Methamphetamine (Meth) can evoke extreme hyperthermia, which correlates with neurotoxicity and death in laboratory animals and humans. The objective of this study was to uncover the mechanisms of a complex dose dependence of temperature responses to Meth by mathematical modeling of the neuronal circuitry. On the basis of previous studies, we composed an artificial neural network with the core comprising three sequentially connected nodes: excitatory, medullary, and sympathetic preganglionic neuronal (SPN). Meth directly stimulated the excitatory node, an inhibitory drive targeted the medullary node, and, in high doses, an additional excitatory drive affected the SPN node. All model parameters (weights of connections, sensitivities, and time constants) were subject to fitting experimental time series of temperature responses to 1, 3, 5, and 10 mg/kg Meth. Modeling suggested that the temperature response to the lowest dose of Meth, which caused an immediate and short hyperthermia, involves neuronal excitation at a supramedullary level. The delay in response after the intermediate doses of Meth is a result of neuronal inhibition at the medullary level. Finally, the rapid and robust increase in body temperature induced by the highest dose of Meth involves activation of high-dose excitatory drive. The impairment in the inhibitory mechanism can provoke a life-threatening temperature rise and makes it a plausible cause of fatal hyperthermia in Meth users. We expect that studying putative neuronal sites of Meth action and the neuromediators involved in a detailed model of this system may lead to more effective strategies for prevention and treatment of hyperthermia induced by amphetamine-like stimulants. PMID:24500434

Deglacial temperature history of West Antarctica

NASA Astrophysics Data System (ADS)

Cuffey, Kurt M.; Clow, Gary D.; Steig, Eric J.; Buizert, Christo; Fudge, T. J.; Koutnik, Michelle; Waddington, Edwin D.; Alley, Richard B.; Severinghaus, Jeffrey P.

2016-12-01

The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth’s climate responds to various forcings, including a rise in atmospheric CO2. This transition has left a direct thermal remnant in the polar ice sheets, where the exceptional purity and continual accumulation of ice permit analyses not possible in other settings. For Antarctica, the deglacial warming has previously been constrained only by the water isotopic composition in ice cores, without an absolute thermometric assessment of the isotopes’ sensitivity to temperature. To overcome this limitation, we measured temperatures in a deep borehole and analyzed them together with ice-core data to reconstruct the surface temperature history of West Antarctica. The deglacial warming was 11.3±1.8∘11.3±1.8∘C, approximately two to three times the global average, in agreement with theoretical expectations for Antarctic amplification of planetary temperature changes. Consistent with evidence from glacier retreat in Southern Hemisphere mountain ranges, the Antarctic warming was mostly completed by 15 kyBP, several millennia earlier than in the Northern Hemisphere. These results constrain the role of variable oceanic heat transport between hemispheres during deglaciation and quantitatively bound the direct influence of global climate forcings on Antarctic temperature. Although climate models perform well on average in this context, some recent syntheses of deglacial climate history have underestimated Antarctic warming and the models with lowest sensitivity can be discounted.

External cooling efficiently controls intraosseous temperature rise caused by drilling in a drilling guide system: an in vitro study.

PubMed

Boa, Kristof; Varga, Endre; Pinter, Gabor; Csonka, Akos; Gargyan, Istvan; Varga, Endre

2015-12-01

The purpose of this study was to measure the rise in intraosseous temperature caused by drilling through a drilling guide system. We compared the rise in temperature generated, and the number of increases of more than 10 °C, between drills that had been cooled with saline at room temperature (25 °C) and those that had not been cooled, for every step of the drilling sequence. Cortical layers of bovine ribs were used as specimens, and they were drilled through 3-dimensional printed surgical guides. Heat was measured with an infrared thermometer. The significance of differences was assessed with either a two-sample t test or Welch's test, depending on the variances. The mean rises (number of times that the temperature rose above 10 °C) for each group of measurements were: for the 2mm drill, 4.8 °C (0/48) when cooled and 7.0 °C (8/48) when not cooled; with the 2.5mm drill, 5.2 °C (1/48) when cooled and 8.5 °C (17/48) when not cooled (2 mm canal); with the 3 mm drill, 3.3 °C when cooled (0/48) and 8.5 °C (18/24) when not cooled (2.5 mm canal); and with the 3.5 mm drill, 4.8 °C when cooled (0/24) and 9.4 °C when not cooled (10/23) (3 mm canal). The temperature rose significantly less with cooling at every step of the drilling sequence (p<0.001). We conclude that external cooling can maintain the intraosseous temperature within the safe range while drilling through an implant guide system, whereas drilling without irrigation can lead to temperatures that exceed the acceptable limit. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Evaluation of Erosion of the Dummy “EE” Plate 19 in YA Type ATR Fuel Element During Reactor PALM Cycles

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

Brower, Jeffrey O.; Glazoff, Michael V.; Eiden, Thomas J.

Advanced Test Reactor (ATR) Cycle 153B-1 was a 14-day, high-power, powered axial locator mechanism (PALM) operating cycle that completed on April 12, 2013. Cycle 153B-1 was a typical operating cycle for the ATR, and did not result in any unusual plant transients. ATR was started up and shut down as scheduled. The PALM drive physically moves the selected experiments into and out of the core to simulate reactor startup and heat up, and shutdown and cooldown transients, while the reactor remains in steady-state conditions. However, after the cycle was over, when the fuel elements were removed from the core andmore » inspected, several thousand flow-assisted erosion pits and “horseshoeing” defects were readily observed on the surface of the several YA-type fuel elements (these are aluminum “dummy” plates that contain no fuel). In order to understand these erosion phenomena, a thermal-hydraulic model of coolant channel 20 on a YA-M fuel element was generated. The boundaries of the model were the aluminum EE plate of a YA-M fuel element and a beryllium reflector block with 13 horizontal saw cuts which represented regions of zero flow. The heat generated in fuel plates 1 through 18 was modeled to be passing through the aluminum EE plate. The coolant channel 20 width was set at 0.058 in. (58 mils). It was established that the horizontal saw cuts had a significant effect on the temperature of the coolant. The flow, which was expected to vary linearly with gradual heating of the coolant as it passed through the channel, was extremely turbulent. The temperature rise, which was expected to be a smooth “S” curve, was represented by a series temperature rise “humps,” which occurred at each horizontal saw cut in the beryllium reflector block. Each of the 13 saw cuts had a chamfered edge which resulted in the coolant flow being re-directed as a jet across the coolant channel into the surface of the EE plate, which explained the temperature rise and the observed scalloping and pitting degradation on the YA-M fuel elements. In the case of scalloping (horseshoeing) a surprising similarity of that defect to those appearing on aluminum plate rolled in over-lubrication conditions, were established. In turn, this made us think that the principal feature responsible for the appearance of these defects, was horizontal cuts in the beryllium reflector block created to arrest the propagation of large vertical crack(s) in Be in PALM cycles with higher overall fluence. This assumption was fully confirmed by the results of thermo-hydraulic simulations. The neutronics data for these modeling experiments were provided using advanced irradiation simulations (MCNP, HELIOS). In the case of pitting erosion the following corrective measures were proposed based upon the results of JMatPro v.8.2 modeling (TTT- and CCT-diagrams): change the fabrication process by adding blister anneal before program anneal, immediately after cold rolling of AA6061plate. This step will allow achieving complete recrystallization, eliminating of strengthening due to metastable precipitates, and reduce the possibility of forming sharp microstructural features upon the surface.« less

Temperature changes across porcelain during multiple exposure CO2 lasing

NASA Astrophysics Data System (ADS)

Barron, Joseph R.; Zakariasen, Kenneth L.; Peacocke, Larry

1990-06-01

Research indicates that laser energy may provide a useful method for glazing and fusing porcelain for intraoral prosthetic purposes. However, it is not known whether such lasing will result in the production of heat levels that may be damaging to adjacent vital tissues such as the dental pulp and periodontal tissues. This research is designed to measure the magnitude of temperature rise across porcelain observed during multiple exposure C02 lasing. Fifteen porcelain examples of 1000 jim (5), 1500 pm (5) and 2000 tm (5) x each received five C02 laser exposures on the same exposure site at 1.0 sec. intervals at 8.0 watts (0.2 sec. per exposure with a 1 mm focal spot). A YSI 144201 thermilinear precision thermistor was placed on the porcelain surface opposite each laser exposure site. Temperature rise above ambient was recorded by an HP3421A data acquisition unit and HP9816 technical microcomputer. Recording continued for sufficient time to allow temperatures to return to ambient. The mean temperature elevations ranged from a low of 2.97 0C (2000 pm) to a high of 7.77 °C (1000 μm). ANOVA and Duncan's Multiple Range Test indicated significant differences in temperature rise by porcelain thickness. It would appear from the results of this research that temperature elevations adjacent to lased porcelain may be sufficiently controllable that safe intraoral porcelain lasing will be possible.

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

Penner, J.E.

The magnitude of the chlorofluoromethane (CFM) induced depletion of the ozone layer is considered a key problem in atmospheric research. The historical rise in the atmospheric concentrations of CFCl/sub 3/, and CF/sub 2/Cl/sub 2/, the major CFM species, is well documented. Atmospheric CO/sub 2/ has also been increasing. Instead of depleting O/sub 3/, the expected effect of CO/sub 2/ is to increase its concentration. The simultaneous effects of these perturbations were studied. Results indicate that increases in CO/sub 2/ can significantly alter the predicted ozone trend. This will complicate efforts to detect the trend in O/sub 3/ caused by increasesmore » in CFM's. Since the calculated effects of these perturbations are largest at high altitudes, one might expect to detect changes in high altitude O/sub 3/ sooner than those in total O/sub 3/. Therefore a comparison was made between the calculated change in O/sub 3/ at high altitude and statistical detection limits for abnormal change as developed from Umkehr data from Arosa, Switzerland. Its significance for trend detection is discussed. Finally, since CO/sub 2/ effects will be important in the next 50 to 100 years, the effects of temperature changes from CO/sub 2/ increase on O/sub 3/ loss rates from different families were examined. Significant changes in the NO/sub x/-catalyzed ozone loss rates that have not previously been discussed were found. It is concluded that the O/sub 3/ decrease at steady state from the coupled CFM and CO/sub 2/ perturbation is larger than the decrease calculated by summing the separate effects of these perturbations. The expected increase in CO/sub 2/ can significantly affect predicted O/sub 3/ trends in the next 50 to 100 years. O/sub 3/ changes in Umkehr level 7 are more detectible, in a statistical sense, than those at higher levels. The temperature effect of CO/sub 2/ on the NO/sub x-catalyzed O/sub 3/ destruction rate was found to be as large or larger than the effect of temperature on the pure oxygen loss rate.« less

Health Impacts in a Changing Climate - An Overview

NASA Astrophysics Data System (ADS)

Louis, V. R.; Phalkey, R. K.

2016-05-01

In the past decades the topic of climate change has been subjected to intense scientific scrutiny, and since the mid-1990's it has become an increasingly political issue. Because of increased temperatures and more frequent and intense extreme weather events, the number of direct injuries and deaths will increase, along with infectious diseases, whether food, water or vector-borne; respiratory and cardiovascular diseases are expected to rise due to worsened air pollution and extreme heat. In a context of on-going environmental degradation, local food-producing systems, both marine and terrestrial, will be affected and the risk of malnutrition, especially in children, will increase. These impacts on health and livelihood are expected to be significant factors in the spread of regional social crises, potentially leading to forced migration, conflicts and increased poverty. The link between health and climate change operates through a variety of pathways that are now well established. In addition to taking climate mitigation measures, it will also be necessary to take adaptation measures, such as strengthening health systems, improving preparedness and developing early warning systems. There is now a broad scientific consensus on the issue and the science is sufficiently robust to enable a coordinated response to meet this global challenge.

Forecasted Impact of Climate Change on Infectious Disease and Health Security in Hawaii by 2050.

PubMed

Canyon, Deon V; Speare, Rick; Burkle, Frederick M

2016-12-01

Climate change is expected to cause extensive shifts in the epidemiology of infectious and vector-borne diseases. Scenarios on the effects of climate change typically attribute altered distribution of communicable diseases to a rise in average temperature and altered incidence of infectious diseases to weather extremes. Recent evaluations of the effects of climate change on Hawaii have not explored this link. It may be expected that Hawaii's natural geography and robust water, sanitation, and health care infrastructure renders residents less vulnerable to many threats that are the focus on smaller, lesser developed, and more vulnerable Pacific islands. In addition, Hawaii's communicable disease surveillance and response system can act rapidly to counter increases in any disease above baseline and to redirect resources to deal with changes, particularly outbreaks due to exotic pathogens. The evidence base examined in this article consistently revealed very low climate sensitivity with respect to infectious and mosquito-borne diseases. A community resilience model is recommended to increase adaptive capacity for all possible climate change impacts rather an approach that focuses specifically on communicable diseases. (Disaster Med Public Health Preparedness. 2016;10:797-804).

Rise of pairwise thermal entanglement for an alternating Ising and Heisenberg spin chain in an arbitrarily oriented magnetic field

NASA Astrophysics Data System (ADS)

Rojas, M.; de Souza, S. M.; Rojas, Onofre

2014-03-01

Typically two particles (spins) could be maximally entangled at zero temperature, and for a certain temperature the phenomenon of entanglement vanishes at the threshold temperature. For the Heisenberg coupled model or even the Ising model with a transverse magnetic field, one can observe some rise of entanglement even for a disentangled region at zero temperature. So we can understand this emergence of entanglement at finite temperature as being due to the mixing of some maximally entangled states with some other untangled states. Here, we present a simple one-dimensional Ising model with alternating Ising and Heisenberg spins in an arbitrarily oriented magnetic field, which can be mapped onto the classical Ising model with a magnetic field. This model does not show any evidence of entanglement at zero temperature, but surprisingly at finite temperature rise a pairwise thermal entanglement between two untangled spins at zero temperature when an arbitrarily oriented magnetic field is applied. This effect is a purely magnetic field, and the temperature dependence, as soon as the temperature increases, causes a small increase in concurrence, achieving its maximum at around 0.1. Even for long-range entanglement, a weak concurrence still survives. There are also some real materials that could serve as candidates that would exhibit this effect, such as Dy(NO3)(DMSO)2Cu(opba)(DMSO)2 [DMSO = dimethyl sulfoxide; opba = o-phenylenebis(oxamoto)] [J. Strečka, M. Hagiwara, Y. Han, T. Kida, Z. Honda, and M. Ikeda, Condens. Matter Phys. 15, 43002 (2012), 10.5488/CMP.15.43002].

The effect of temperature on different Salmonella serotypes during warm seasons in a Mediterranean climate city, Adelaide, Australia.

PubMed

Milazzo, A; Giles, L C; Zhang, Y; Koehler, A P; Hiller, J E; Bi, P

2016-04-01

Changing trends in foodborne disease are influenced by many factors, including temperature. Globally and in Australia, warmer ambient temperatures are projected to rise if climate change continues. Salmonella spp. are a temperature-sensitive pathogen and rising temperature can have a substantial effect on disease burden affecting human health. We examined the relationship between temperature and Salmonella spp. and serotype notifications in Adelaide, Australia. Time-series Poisson regression models were fit to estimate the effect of temperature during warmer months on Salmonella spp. and serotype cases notified from 1990 to 2012. Long-term trends, seasonality, autocorrelation and lagged effects were included in the statistical models. Daily Salmonella spp. counts increased by 1·3% [incidence rate ratio (IRR) 1·013, 95% confidence interval (CI) 1·008-1·019] per 1 °C rise in temperature in the warm season with greater increases observed in specific serotype and phage-type cases ranging from 3·4% (IRR 1·034, 95% CI 1·008-1·061) to 4·4% (IRR 1·044, 95% CI 1·024-1·064). We observed increased cases of S. Typhimurium PT9 and S. Typhimurium PT108 notifications above a threshold of 39 °C. This study has identified the impact of warm season temperature on different Salmonella spp. strains and confirms higher temperature has a greater effect on phage-type notifications. The findings will contribute targeted information for public health policy interventions, including food safety programmes during warmer weather.

An Integrated Framework to Analyze Local Decision Making and Adaptation to Sea-Level Rise in Coastal Regions in Santos-Brazil, Broward County-USA and Selsey-UK

NASA Astrophysics Data System (ADS)

Marengo, J. A.; Muller-Karger, F. E.; Pelling, M.; Reynolds, C. J.; Merril, S. B.; Nunes, L. H.; Paterson, S.; Gray, A.; Lockman, J. T.; Kartez, J.; Moreira, F.; Greco, R.; Harari, J.; Souza, C. G.; Alves, L. M.; Hosokawa, E.; Tabuchi, E.

2016-12-01

One of the clear signals of present climate change is sea level rise (SLR). There is mounting evidence of other changes, including warmer temperatures in many localities, and changes in the intensity and frequency of extreme meteorological events, including wind, rain, and waves. A rising sea level combined with these factors and tides is expected to affect coastal communities through a number of processes, including increased risk of flooding and contamination of water sources. An international collaboration between Brazil, the United Kingdom, and the United States was designed to evaluate local decision making processes and to open convening space for local urban managers to reflect on possible actions toward adaption to SLR and the constraints imposed by framing administrative and institutional structures. The overall goal of the project is to help coastal communities better understand factors that facilitate or hinder their intrinsic, local decision-making processes related to planning for adaptation to risk. The project carried out these tests in 2014 and 2015 in one coastal city in each partnering nation. The framework was designed by an interdisciplinary team that incorporated social and natural scientists from these three nations, and which included local government officials. To support the overall goal, this paper 1) discusses some aspects of adaptive capacity and participant survey research conducted through the project, 2) presents technical modelling results for adaptation options that may reduce the potential damages of SLR and storm surge in each location, and 3) identifies project design considerations for similar transnational adaptation projects.

Climate change at northern latitudes: rising atmospheric humidity decreases transpiration, N-uptake and growth rate of hybrid aspen.

PubMed

Tullus, Arvo; Kupper, Priit; Sellin, Arne; Parts, Leopold; Sõber, Jaak; Tullus, Tea; Lõhmus, Krista; Sõber, Anu; Tullus, Hardi

2012-01-01

At northern latitudes a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. We studied several growth and functional traits of hybrid aspen (Populus tremula L.×P. tremuloides Michx.) in response to elevated atmospheric humidity (on average 7% over the ambient level) in a free air experimental facility during three growing seasons (2008-2010) in Estonia, which represents northern temperate climate (boreo-nemoral zone). Data were collected from three humidified (H) and three control (C) plots, and analysed using nested linear models. Elevated air humidity significantly reduced height, stem diameter and stem volume increments and transpiration of the trees whereas these effects remained highly significant also after considering the side effects from soil-related confounders within the 2.7 ha study area. Tree leaves were smaller, lighter and had lower leaf mass per area (LMA) in H plots. The magnitude and significance of the humidity treatment effect--inhibition of above-ground growth rate--was more pronounced in larger trees. The lower growth rate in the humidified plots can be partly explained by a decrease in transpiration-driven mass flow of NO(3) (-) in soil, resulting in a significant reduction in the measured uptake of N to foliage in the H plots. The results suggest that the potential growth improvement of fast-growing trees like aspens, due to increasing temperature and atmospheric CO(2) concentration, might be smaller than expected at high latitudes if a rise in atmospheric humidity simultaneously takes place.

Climate Change at Northern Latitudes: Rising Atmospheric Humidity Decreases Transpiration, N-Uptake and Growth Rate of Hybrid Aspen

PubMed Central

Tullus, Arvo; Kupper, Priit; Sellin, Arne; Parts, Leopold; Sõber, Jaak; Tullus, Tea; Lõhmus, Krista; Sõber, Anu; Tullus, Hardi

2012-01-01

At northern latitudes a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. We studied several growth and functional traits of hybrid aspen (Populus tremula L.×P. tremuloides Michx.) in response to elevated atmospheric humidity (on average 7% over the ambient level) in a free air experimental facility during three growing seasons (2008–2010) in Estonia, which represents northern temperate climate (boreo-nemoral zone). Data were collected from three humidified (H) and three control (C) plots, and analysed using nested linear models. Elevated air humidity significantly reduced height, stem diameter and stem volume increments and transpiration of the trees whereas these effects remained highly significant also after considering the side effects from soil-related confounders within the 2.7 ha study area. Tree leaves were smaller, lighter and had lower leaf mass per area (LMA) in H plots. The magnitude and significance of the humidity treatment effect – inhibition of above-ground growth rate – was more pronounced in larger trees. The lower growth rate in the humidified plots can be partly explained by a decrease in transpiration-driven mass flow of NO3 − in soil, resulting in a significant reduction in the measured uptake of N to foliage in the H plots. The results suggest that the potential growth improvement of fast-growing trees like aspens, due to increasing temperature and atmospheric CO2 concentration, might be smaller than expected at high latitudes if a rise in atmospheric humidity simultaneously takes place. PMID:22880067

A search for scale in sea-level studies

USGS Publications Warehouse

Larsen, C.E.; Clark, I.

2006-01-01

Many researchers assume a proportional relationship among the atmospheric CO2 concentration, temperature, and sea level. Thus, the rate of sea-level rise should increase in concert with the documented exponential increase in CO2. Although sea surface temperature has increased in places over the past century and short-term sea level rose abruptly during the 1990s, it is difficult to demonstrate a proportional relationship using existing geologic or historic records. Tide gauge records in the United States cover too short a time interval to verify acceleration in the rate of sea-level rise, although multicentury tide gauge and staff records from the Netherlands and Sweden suggest a mid-19th-century acceleration in sea-level rise. Reconstructions of sea-level changes for the past 1000 years derived using benthic foraminifer data from salt marshes along the East Coast of the United States suggest an increased rate of relative sea-level rise beginning in the 1600s. Geologic records of relative sea-level rise for the past 6000 years are available for several sites along the US East Coast from 14C-dated basal peat below salt marshes and estuarine sediments. When these three scales of sea-level variation are integrated, adjusted for postglacial isostatic movement, and replotted, the range of variation in sea level suggested by basal peat ages is within ??1 meter of the long-term trend. The reconstruction from Long Island Sound data shows a linear rise in sea level beginning in the mid-1600s at a rate consistent with the historic record of mean high water. Long-term tide gauge records from Europe and North America show similar trends since the mid-19th century. There is no clear proportional exponential increase in the rate of sea-level rise. If proportionality exists among sea level, atmospheric CO2, and temperature, there may be a significant time lag before an anthropogenic increase in the rate of sea-level rise occurs.

Climate change and managing water crisis: Pakistan's perspective.

PubMed

Hussain, Mumtaz; Mumtaz, Saniea

2014-01-01

Climate change is a global phenomenon manifested mainly through global warming. The International Panel on Climate Change (IPCC) has reported its negative consequences on natural resources, anthropogenic activities, and natural disasters. The El Nino and La Nina have affected hydrologic regimes and ecosystems. It has been observed that the average temperature in 1995 was 0.4°C higher than that in 1895. By the end of the 21st century, 10% of the area of Bangladesh is likely to be submerged by the sea. Most of the islands of Pacific Ocean will disappear. A major part of Maldives will be submerged. The sea level is expected to rise by 30-150 cm. Extreme events such as floods, cyclones, tsunamis, and droughts have become regular phenomena in many parts of the world. Other adverse impacts are proliferation of water-borne diseases, sea water intrusion, salinization of coastal areas, loss of biodiversity, eco-degradation of watersheds and global glacial decline, and haphazard snow melts/thaws. In turn, these factors have serious effect on water resources. Pakistan is confronting similar climate change. Meteorological data reveal that winter temperatures are rising and summers are getting cooler. Temperature is expected to increase by 0.9°C and 1.5°C by years 2020 and 2050, respectively. Water resources in Pakistan are affected by climate change as it impacts the behavior of glaciers, rainfall patterns, greenhouse gas emissions, recurrence of extreme events such as floods and droughts. Severe floods have occurred in the years 1950, 1956, 1957, 1973, 1976, 1978, 1988, 1992, 2010, 2011, and 2012. Pakistan has faced the worst-ever droughts during the period from 1998 to 2004. Pakistan has surface water potential of 140 million acre feet (MAF) and underground water reserve of 56 MAF. It is one of the most water-stressed countries in the world. The per capita annual availability of water has reduced from 5140 m3 in 1950 to 1000 m3 now. It is fast approaching towards water scarcity. To minimize adverse impacts of climate change on the water crisis in Pakistan, the preparation of integrated national, provincial, and local level master plans encompassing technical, social, environmental, administrative, and financial considerations is necessary. It is imperative to implement two simultaneous approaches of adaptation (living with climate change) and mitigation (addressing negativities of climate change). Salient features are integrated management of watersheds/catchments/water bodies, optimum exploitation of present sources, development of new sources, water conservation, adequate drainage, efficient design of water storage, conveyance, distribution and supply systems, utilization of waste water, and regulation of water quality.

Signals from the planets, via the Sun to the Earth

NASA Astrophysics Data System (ADS)

Solheim, J.-E.

2013-12-01

The best method for identification of planetary forcing of the Earth's climate is to investigate periodic variations in climate time series. Some natural frequencies in the Earth climate system seem to be synchronized to planetary cycles, and amplified to a level of detection. The response by the Earth depends on location, and in global averaged series, some planetary signals may be below detection. Comparing sea level rise with sunspot variations, we find phase variations, and even a phase reversal. A periodogram of the global temperature shows that the Earth amplifies other periods than observed in sunspots. A particular case is that the Earth amplifies the 22 yr Hale period, and not the 11 yr Schwabe period. This may be explained by alternating peak or plateau appearance of cosmic ray counts. Among longer periods, the Earth amplifies the 60 yr planetary period and keeps the phase during centennials. The recent global warming may be interpreted as a rising branch of a millennium cycle, identified in ice cores and sediments and also recorded in history. This cycle peaks in the second half of this century, and then a 500 yr cooling trend will start. An expected solar grand minimum due to a 200 yr cycle will introduce additional cooling in the first part of this century.

Systematic variation in the temperature dependence of physiological and ecological traits.

PubMed

Dell, Anthony I; Pawar, Samraat; Savage, Van M

2011-06-28

To understand the effects of temperature on biological systems, we compile, organize, and analyze a database of 1,072 thermal responses for microbes, plants, and animals. The unprecedented diversity of traits (n = 112), species (n = 309), body sizes (15 orders of magnitude), and habitats (all major biomes) in our database allows us to quantify novel features of the temperature response of biological traits. In particular, analysis of the rising component of within-species (intraspecific) responses reveals that 87% are fit well by the Boltzmann-Arrhenius model. The mean activation energy for these rises is 0.66 ± 0.05 eV, similar to the reported across-species (interspecific) value of 0.65 eV. However, systematic variation in the distribution of rise activation energies is evident, including previously unrecognized right skewness around a median of 0.55 eV. This skewness exists across levels of organization, taxa, trophic groups, and habitats, and it is partially explained by prey having increased trait performance at lower temperatures relative to predators, suggesting a thermal version of the life-dinner principle-stronger selection on running for your life than running for your dinner. For unimodal responses, habitat (marine, freshwater, and terrestrial) largely explains the mean temperature at which trait values are optimal but not variation around the mean. The distribution of activation energies for trait falls has a mean of 1.15 ± 0.39 eV (significantly higher than rises) and is also right-skewed. Our results highlight generalities and deviations in the thermal response of biological traits and help to provide a basis to predict better how biological systems, from cells to communities, respond to temperature change.

Systematic variation in the temperature dependence of physiological and ecological traits

PubMed Central

Dell, Anthony I.; Pawar, Samraat; Savage, Van M.

2011-01-01

To understand the effects of temperature on biological systems, we compile, organize, and analyze a database of 1,072 thermal responses for microbes, plants, and animals. The unprecedented diversity of traits (n = 112), species (n = 309), body sizes (15 orders of magnitude), and habitats (all major biomes) in our database allows us to quantify novel features of the temperature response of biological traits. In particular, analysis of the rising component of within-species (intraspecific) responses reveals that 87% are fit well by the Boltzmann–Arrhenius model. The mean activation energy for these rises is 0.66 ± 0.05 eV, similar to the reported across-species (interspecific) value of 0.65 eV. However, systematic variation in the distribution of rise activation energies is evident, including previously unrecognized right skewness around a median of 0.55 eV. This skewness exists across levels of organization, taxa, trophic groups, and habitats, and it is partially explained by prey having increased trait performance at lower temperatures relative to predators, suggesting a thermal version of the life-dinner principle—stronger selection on running for your life than running for your dinner. For unimodal responses, habitat (marine, freshwater, and terrestrial) largely explains the mean temperature at which trait values are optimal but not variation around the mean. The distribution of activation energies for trait falls has a mean of 1.15 ± 0.39 eV (significantly higher than rises) and is also right-skewed. Our results highlight generalities and deviations in the thermal response of biological traits and help to provide a basis to predict better how biological systems, from cells to communities, respond to temperature change. PMID:21606358

Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

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

Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

2009-09-27

To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoommore » activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.« less

Analysis of key factors influencing the evaporation performances of an oriented linear cutting copper fiber sintered felt

NASA Astrophysics Data System (ADS)

Pan, Minqiang; Zhong, Yujian

2018-01-01

Porous structure can effectively enhance the heat transfer efficiency. A kind of micro vaporizer using the oriented linear cutting copper fiber sintered felt is proposed in this work. Multiple long cutting copper fibers are firstly fabricated with a multi-tooth tool and then sintered together in parallel to form uniform thickness metal fiber sintered felts that provided a characteristic of oriented microchannels. The temperature rise response and thermal conversion efficiency are experimentally investigated to evaluate the influences of porosity, surface structure, feed flow rate and input power on the evaporation characteristics. It is indicated that the temperature rise response of water is mainly affected by input power and feed flow rate. High input power and low feed flow rate present better temperature rise response of water. Porosity rather than surface structure plays an important role in the temperature rise response of water at a relatively high input power. The thermal conversion efficiency is dominated by the input power and surface structure. The oriented linear cutting copper fiber sintered felts for three kinds of porosities show better thermal conversion efficiency than that of the oriented linear copper wire sintered felt when the input power is less than 115 W. All the sintered felts have almost the same performance of thermal conversion at a high input power.

Assessment of the computational uncertainty of temperature rise and SAR in the eyes and brain under far-field exposure from 1 to 10 GHz

NASA Astrophysics Data System (ADS)

Laakso, Ilkka

2009-06-01

This paper presents finite-difference time-domain (FDTD) calculations of specific absorption rate (SAR) values in the head under plane-wave exposure from 1 to 10 GHz using a resolution of 0.5 mm in adult male and female voxel models. Temperature rise due to the power absorption is calculated by the bioheat equation using a multigrid method solver. The computational accuracy is investigated by repeating the calculations with resolutions of 1 mm and 2 mm and comparing the results. Cubically averaged 10 g SAR in the eyes and brain and eye-averaged SAR are calculated and compared to the corresponding temperature rise as well as the recommended limits for exposure. The results suggest that 2 mm resolution should only be used for frequencies smaller than 2.5 GHz, and 1 mm resolution only under 5 GHz. Morphological differences in models seemed to be an important cause of variation: differences in results between the two different models were usually larger than the computational error due to the grid resolution, and larger than the difference between the results for open and closed eyes. Limiting the incident plane-wave power density to smaller than 100 W m-2 was sufficient for ensuring that the temperature rise in the eyes and brain were less than 1 °C in the whole frequency range.

Glacier evolution in high-mountain Asia under stratospheric sulfate aerosol injection geoengineering

NASA Astrophysics Data System (ADS)

Zhao, Liyun; Yang, Yi; Cheng, Wei; Ji, Duoying; Moore, John C.

2017-06-01

Geoengineering by stratospheric sulfate aerosol injection may help preserve mountain glaciers by reducing summer temperatures. We examine this hypothesis for the glaciers in high-mountain Asia using a glacier mass balance model driven by climate simulations from the Geoengineering Model Intercomparison Project (GeoMIP). The G3 and G4 schemes specify use of stratospheric sulfate aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario for the 50 years between 2020 and 2069, and for a further 20 years after termination of geoengineering. We estimate and compare glacier volume loss for every glacier in the region using a glacier model based on surface mass balance parameterization under climate projections from three Earth system models under G3, five models under G4, and six models under RCP4.5 and RCP8.5. The ensemble projections suggest that glacier shrinkage over the period 2010-2069 is equivalent to sea-level rise of 9.0 ± 1.6 mm (G3), 9.8 ± 4.3 mm (G4), 15.5 ± 2.3 mm (RCP4.5), and 18.5 ± 1.7 mm (RCP8.5). Although G3 keeps the average temperature from increasing in the geoengineering period, G3 only slows glacier shrinkage by about 50 % relative to losses from RCP8.5. Approximately 72 % of glaciated area remains at 2069 under G3, as compared with about 30 % for RCP8.5. The widely reported reduction in mean precipitation expected for solar geoengineering is unlikely to be as important as the temperature-driven shift from solid to liquid precipitation for forcing Himalayan glacier change. The termination of geoengineering at 2069 under G3 leads to temperature rise of about 1.3 °C over the period 2070-2089 relative to the period 2050-2069 and corresponding increase in annual mean glacier volume loss rate from 0.17 to 1.1 % yr-1, which is higher than the 0.66 % yr-1 under RCP8.5 during 2070-2089.

Temperature history of the Caribbean mixed layer as derived from sclerosponges

NASA Astrophysics Data System (ADS)

Estrella, J.; Winter, A.; Sherman, C.; Mangini, A.; Ramírez, W.

2011-12-01

We present a high resolution record of the Caribbean mixed layer temperature at different depths derived from oxygen isotopic ratios obtained from the sclerosponge Ceratoporella nicholsoni. Sclerosponges precipitate their calcium carbonate skeleton in equilibrium with their surrounding environment and are capable of living at great depths (down to 200 m). The sponges for this project were collected off Puerto Rico and St. Croix in northeastern region of the Caribbean Sea. The record obtained closest to the surface (36 m) indicates a sudden rise in sea surface temperature that started in 1866 and ended in 1877 with a total rise of 0.5 °C. At this time the rise decelerated until it finally stopped in 1935. From there onwards the record shows a declining trend that lasts until present day. We found that up to 51 % of the temperature variability in this record can be attributed to the Atlantic Multidecadal Oscillation (Trenberth and Shea, 2006). Further work is taking place on sponges located at various depths to determine the rate of expansion of the mixed layer.

Transient temperature distributions in simple conducting bodies steadily heated through a laminar boundary layer

NASA Technical Reports Server (NTRS)

Parker, Hermon M

1953-01-01

An analysis is made of the transient heat-conduction effects in three simple semi-infinite bodies: the flat insulated plate, the conical shell, and the slender solid cone. The bodies are assumed to have constant initial temperatures and, at zero time, to begin to move at a constant speed and zero angle of attack through a homogeneous atmosphere. The heat input is taken as that through a laminar boundary layer. Radiation heat transfer and transverse temperature gradients are assumed to be zero. The appropriate heat-conduction equations are solved by an iteration method, the zeroeth-order terms describing the situation in the limit of small time. The method is presented and the solutions are calculated to three orders which are sufficient to give reasonably accurate results when the forward edge has attained one-half the total temperature rise (nose half-rise time). Flight Mach number and air properties occur as parameters in the result. Approximate expressions for the extent of the conduction region and nose half-rise times as functions of the parameters of the problem are presented. (author)

Relationship between extreme Precipitation and Temperature over Japan: An analysis from Multi-GCMs and Multi-RCMs products

NASA Astrophysics Data System (ADS)

Nayak, S.; Dairaku, K.; Takayabu, I.

2014-12-01

According to the IPCC reports, the concentration of CO­2 has been increasing and projected to be increased significantly in future (IPCC, 2012). This can have significant impacts on climate. For instance, Dairaku and Emori (2006) examined over south Asia by doubling CO2 and documented an increase in precipitation intensities during Indian summer monsoon. This would increase natural disasters such as floods, landslide, coastal disaster, erosion etc. Recent studies investigated whether the rate of increase of extreme precipitation is related with the rate expected by Clausius-Clapeyron (CC) relationship (approximately 7% per degree temperature rise). In our study, we examine whether this rate can increase or decrease in the future regional climate scenarios over Japan. We have analysed the ensemble experiments by three RCMs(NHRCM, NRAMS, WRF) forced by JRA25 as well as three GCMs (CCSM4, MIROC5, MRI-GCM3) for the current climate (1981-2000) and future scenario (2081-2100, RCP4.5) over Japan. We have stratified the extreme (99th, 95th, 90th, 75th percentile) precipitation of daily sum and daily maximum of hourly precipitation intensities of wet events based on daily mean temperature in bins of 1°C width for annual as well as for each season (DJF, MAM, JJA, SON). The results indicate that precipitation intensity increases when temperature increases roughly up to 22 °C and further increase of temperature decreases the precipitation intensities. The obtained results are consistent and match with the observation (APHRODITE dataset) over Japan. The decrease of precipitation at higher temperature mainly can be found in JJA. It is also noticed that the rate of specific humidity is estimated higher during JJA than other seasons. The rate of increase of extreme precipitation is similar to the rate expected by CC relation except DJF (nearly twice of CC relation) in current climate. This rate becomes to be significantly larger in future scenario for higher temperatures than in current climate.Acknowledgement: This study is conducted as part of a research at NIED, Japan (PI: Koji Dairaku) of Research Program on Climate Change Adaptation (RECCA) and was supported by the SOUSEI Program, funded by Ministry of Education, Culture, Sports, Science and Technology, Government of Japan.

Reforming Student Aid: How to Simplify Tax Aid and Use Performance Metrics to Improve College Choices and Completion

ERIC Educational Resources Information Center

Reimherr, Patrick; Harmon, Tim; Strawn, Julie; Choitz, Vickie

2013-01-01

Over the last three decades, college costs have increased nearly four times faster than median family income. Financial aid has not filled the growing gap, and the share of college costs not covered by financial aid or what the family is expected to contribute has risen sharply. Rising costs and rising debt make college a riskier investment for…

Temperature-dependent body size effects determine population responses to climate warming.

PubMed

Lindmark, Max; Huss, Magnus; Ohlberger, Jan; Gårdmark, Anna

2018-02-01

Current understanding of animal population responses to rising temperatures is based on the assumption that biological rates such as metabolism, which governs fundamental ecological processes, scale independently with body size and temperature, despite empirical evidence for interactive effects. Here, we investigate the consequences of interactive temperature- and size scaling of vital rates for the dynamics of populations experiencing warming using a stage-structured consumer-resource model. We show that interactive scaling alters population and stage-specific responses to rising temperatures, such that warming can induce shifts in population regulation and stage-structure, influence community structure and govern population responses to mortality. Analysing experimental data for 20 fish species, we found size-temperature interactions in intraspecific scaling of metabolic rate to be common. Given the evidence for size-temperature interactions and the ubiquity of size structure in animal populations, we argue that accounting for size-specific temperature effects is pivotal for understanding how warming affects animal populations and communities. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Pregnancy - identifying fertile days

MedlinePlus

... mean ovulation is near. TAKING YOUR BASAL BODY TEMPERATURE After you ovulate, your body temperature will rise and stay at a higher level ... can use a special thermometer to take your temperature in the morning before you get out of ...

Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats.

PubMed

Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

2016-08-01

Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming.

The dissociation of liquid silica at high pressure and temperature

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

Hicks, D; Boehly, T; Eggert, J

2005-11-17

Liquid silica at high pressure and temperature is shown to undergo significant structural modifications and profound changes in its electronic properties. Temperature measurements on shock waves in silica at 70-1000 GPa indicate that the specific heat of liquid SiO{sub 2} rises well above the Dulong-Petit limit, exhibiting a broad peak with temperature that is attributable to the growing structural disorder caused by bond-breaking in the melt. The simultaneous sharp rise in optical reflectivity of liquid SiO{sub 2} indicates that dissociation causes the electrical and therefore thermal conductivities of silica to attain metallic-like values of 1-5 x 10{sup 5} S/m andmore » 24-600 W/m.K respectively.« less

Influence of seating styles on head and pelvic vertical movement symmetry in horses ridden at trot

PubMed Central

Hernlund, Elin; Pfau, Thilo; Haubro Andersen, Pia; Rhodin, Marie

2018-01-01

Detailed knowledge of how a rider’s seating style and riding on a circle influences the movement symmetry of the horse’s head and pelvis may aid rider and trainer in an early recognition of low grade lameness. Such knowledge is also important during both subjective and objective lameness evaluations in the ridden horse in a clinical setting. In this study, inertial sensors were used to assess how different rider seating styles may influence head and pelvic movement symmetry in horses trotting in a straight line and on the circle in both directions. A total of 26 horses were subjected to 15 different conditions at trot: three unridden conditions and 12 ridden conditions where the rider performed three different seating styles (rising trot, sitting trot and two point seat). Rising trot induced systematic changes in movement symmetry of the horses. The most prominent effect was decreased pelvic rise that occurred as the rider was actively rising up in the stirrups, thus creating a downward momentum counteracting the horses push off. This mimics a push off lameness in the hindlimb that is in stance when the rider sits down in the saddle during the rising trot. On the circle, the asymmetries induced by rising trot on the correct diagonal counteracted the circle induced asymmetries, rendering the horse more symmetrical. This finding offers an explanation to the equestrian tradition of rising on the ‘correct diagonal.’ In horses with small pre-existing movement asymmetries, the asymmetry induced by rising trot, as well as the circular track, attenuated or reduced the horse’s baseline asymmetry, depending on the sitting diagonal and direction on the circle. A push off hindlimb lameness would be expected to increase when the rider sits during the lame hindlimb stance whereas an impact hindlimb lameness would be expected to decrease. These findings suggest that the rising trot may be useful for identifying the type of lameness during subjective lameness assessment of hindlimb lameness. This theory needs to be studied further in clinically lame horses. PMID:29621299

Numerical simulations of heat transfer considering hydraulic discontinuity for an enhanced geothermal system development in Seokmo Island, Korea

NASA Astrophysics Data System (ADS)

Shin, J.; Kim, K.; Hyun, Y.; Lee, K.; Lee, T.

2011-12-01

The construction of the first geothermal plant in Korea is under planning in Seokmo Island, where a few artesian wells showing relatively high water temperature of around 70 degrees were discovered lately. Geologic structure in this region is characterized by the fractured granite. Numerical simulations for the temperature evolution in a fractured geothermal reservoir in Seokmo Island under the supposed injection-extraction operating conditions were carried out using TOUGH2. A MINC model including a hydraulic discontinuity in Seokmo Island region, which reflected the analysis from several geophysical explorations and drilled rock core, was generated. Supposing the N05°E, NW83° fracture zone containing the pumping range, the numerical simulation results show that temperature of the extracted geothermal water decreases after 15 years of operation, which decreases the overall efficiency of the expected geothermal plant. This is because the colder water from the injection well, which is 400 m apart, begins to flow into the more permeable fracture zone from the 15th year, resulting in a decrease in temperature near the pumping well. Temperature distribution calculated from the simulation also shows a rise of relatively hot geothermal water along the fracture plane. All of the results are different from the non-fracture MINC model, which shows a low temperature contour in concentric circle shape around the injection well and relatively consistent extracting temperature. This demonstrates that the distribution and the structure of fracture system influence the major mass and heat flow mechanisms in geologic medium. Therefore, an intensive geologic investigation for the fractures including their structure, permeability and connecting relation is important. Acknowledgement This study was financially supported by KIGAM, KETEP and BK21.

Heat Losses from a Breathing System with a Heated-water Humidifier

PubMed Central

Lunn, J. N.; Mapleson, W. W.; Hillard, E. K.

1971-01-01

Air was “breathed” in the laboratory through a heated-water humidifier and a breathing tube. Several different humidifiers and tubes were used. The temperature rise of the air on passing through the humidifier and the temperature drop on passing through the tube were measured. Both were dependent on ventilation. Insulating the tube and humidifier together with the insertion of baffles in the latter reduced the rise and fall and their dependence on ventilation. With suitable design the dependence on ventilation and the need to use high water temperatures could be greatly reduced. In addition, a thermostat with a reduced dead zone is needed. PMID:5289685

Climate Change in Alpine Regions - Regional Characteristics of a Global Phenomenon by the Example of Air Temperature

NASA Astrophysics Data System (ADS)

Lang, Erich; Stary, Ulrike

2017-04-01

For nearly 50 years the Austrian Research Centre for Forests (BFW) has been engaged in research in the Alpine region recording measuring data at extreme sites. Data series of this duration provide already a good insight into the evolution of climate parameters. Extrapolations derived from it are suitable for comparison with results from climate change models or supplement them with regard to their informative value. This is useful because climate change models describe a simplified picture of reality based on the size of the data grid they use. Analysis of time series of two air temperature measuring stations in different torrent catchment areas indicate that 1) predictions of temperature rise for the Alpine region in Austria will have to be revised upwards, and 2) only looking at the data of seasons (or shorter time periods), reveals the real dramatic effect of climate change. Considering e.g. the annual average data of air temperature of the years 1969-2016 at the climate station "Fleissner" (altitude 1210m a.s.l; Upper Mölltal, Carinthia) a significant upward trend is visible. Using a linear smoothing function an increase of the average annual air temperature of about 2.2°C within 50 years emerges. The calculated temperature rise thus confirms the general fear of an increase of more than 2.0°C till the middle of the 21st century. Looking at the seasonal change of air temperature, significant positive trends are shown in all four seasons. But the level of the respective temperature increase varies considerably and indicates the highest increase in spring (+3.3°C), and the lowest one in autumn (+1.3°C, extrapolated for a time period of 50 years). The maximum increase of air temperature at the measuring station "Pumpenhaus" (altitude 980m a.s.l), which is situated in the "Karnische Alpen" in the south of Austria, is even stronger. From a time series of 28 years (with data recording starting in 1989) the maximum rise of temperature was 5.4°C detected for the summer (calculated over a period of 50 years). The predicted overall rise in the annual average temperature within 50 years is +3.9°C, whereas the rise of temperature at the station "Fleissner", located in the "Hohen Tauern", is +2.3°C; both based on determined linear smoothing functions and for the same measuring period (1989-2016). As the effects of the calculated changes of air temperature on the alpine habitat (the entire ecosystem, natural hazards and tourism) and the characteristics of climate change vary strongly from a geographical point of view (as shown by the two examples of air temperature data), a comprehensive analysis of data series from climatic measurement stations (including precipitation, snow covering, radiation…) in the Alpine region is urgently necessary, to be able to work on targeted climate adaptation strategies for these sensitive areas.

Improved hydrocracker temperature control: Mobil quench zone technology

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

Sarli, M.S.; McGovern, S.J.; Lewis, D.W.

1993-01-01

Hydrocracking is a well established process in the oil refining industry. There are over 2.7 million barrels of installed capacity world-wide. The hydrocracking process comprises several families of highly exothermic reactions and the total adiabatic temperature rise can easily exceed 200 F. Reactor temperature control is therefore very important. Hydrocracking reactors are typically constructed with multiple catalyst beds in series. Cold recycle gas is usually injected between the catalyst beds to quench the reactions, thereby controlling overall temperature rise. The design of this quench zone is the key to good reactor temperature control, particularly when processing poorer quality, i.e., highermore » heat release, feeds. Mobil Research and Development Corporation (MRDC) has developed a robust and very effective quench zone technology (QZT) package, which is now being licensed to the industry for hydrocracking applications.« less

Dual direction blower system powered by solar energy to reduce car cabin temperature in open parking condition

NASA Astrophysics Data System (ADS)

Hamdan, N. S.; Radzi, M. F. M.; Damanhuri, A. A. M.; Mokhtar, S. N.

2017-10-01

El-nino phenomenon that strikes Malaysia with temperature recorded more than 35°C can lead to extreme temperature rise in car cabin up to 80°C. Various problems will arise due to this extreme rising of temperature such as the occupant are vulnerable to heat stroke, emission of benzene gas that can cause cancer due to reaction of high temperature with interior compartments, and damage of compartments in the car. The current solution available to reduce car cabin temperature including tinted of window and portable heat rejection device that are available in the market. As an alternative to reduce car cabin temperature, this project modifies the car’s air conditioning blower motor into dual direction powered by solar energy and identifies its influence to temperature inside the car, parked under scorching sun. By reducing the car cabin temperature up to 10°C which equal to 14% of reduction in the car cabin temperature, this simple proposed system aims to provide comfort to users due to its capability in improving the quality of air and moisture in the car cabin.

Effect of a Single Musical Cakra Activation Manoeuvre on Body Temperature: An Exploratory Study

PubMed Central

Sumathy, Sundar; Parmar, Parin N

2016-01-01

Cakra activation/balancing and music therapy are part of the traditional Indian healing system. Little is known about effect of musical (vocal) technique of cakra activation on body temperature. We conducted a single-session exploratory study to evaluate effects of a single musical (vocal) cakra activation manoeuvre on body temperature in controlled settings. Seven healthy adults performed a single musical (vocal) cakra activation manoeuvre for approximately 12 minutes in controlled environmental conditions. Pre- and post-manoeuvre body temperatures were recorded with a clinical mercury thermometer. After a single manoeuvre, increase in body temperature was recorded in all seven subjects. The range of increase in body temperature was from 0.2°F to 1.4°F; with mean temperature rise being 0.5°F and median temperature rise being 0.4°F. We conclude that a single session of musical (vocal) technique of cakra activation elevated body temperatures in all 7 subjects. Further research is required to study effects of various cakra activation techniques on body temperature and other physiological parameters. PMID:28182030

Atomic and molecular hydrogen gas temperatures in a low-pressure helicon plasma

NASA Astrophysics Data System (ADS)

Samuell, Cameron M.; Corr, Cormac S.

2015-08-01

Neutral gas temperatures in hydrogen plasmas are important for experimental and modelling efforts in fusion technology, plasma processing, and surface modification applications. To provide values relevant to these application areas, neutral gas temperatures were measured in a low pressure (< 10 mTorr) radiofrequency helicon discharge using spectroscopic techniques. The atomic and molecular species were not found to be in thermal equilibrium with the atomic temperature being mostly larger then the molecular temperature. In low power operation (< 1 kW), the molecular hydrogen temperature was observed to be linearly proportional to the pressure while the atomic hydrogen temperature was inversely proportional. Both temperatures were observed to rise linearly with input power. For high power operation (5-20 kW), the molecular temperature was found to rise with both power and pressure up to a maximum of approximately 1200 K. Spatially resolved measurements near a graphite target demonstrated localised cooling near the sample surface. The temporal evolution of the molecular gas temperature during a high power 1.1 ms plasma pulse was also investigated and found to vary considerably as a function of pressure.

Effect of a Single Musical Cakra Activation Manoeuvre on Body Temperature: An Exploratory Study.

PubMed

Sumathy, Sundar; Parmar, Parin N

2016-01-01

Cakra activation/balancing and music therapy are part of the traditional Indian healing system. Little is known about effect of musical (vocal) technique of cakra activation on body temperature. We conducted a single-session exploratory study to evaluate effects of a single musical (vocal) cakra activation manoeuvre on body temperature in controlled settings. Seven healthy adults performed a single musical (vocal) cakra activation manoeuvre for approximately 12 minutes in controlled environmental conditions. Pre- and post-manoeuvre body temperatures were recorded with a clinical mercury thermometer. After a single manoeuvre, increase in body temperature was recorded in all seven subjects. The range of increase in body temperature was from 0.2°F to 1.4°F; with mean temperature rise being 0.5°F and median temperature rise being 0.4°F. We conclude that a single session of musical (vocal) technique of cakra activation elevated body temperatures in all 7 subjects. Further research is required to study effects of various cakra activation techniques on body temperature and other physiological parameters.

Future Pacific Rim flows and prices of softwood logs, differentiated by grade.

Treesearch

Donald F. Flora; Andrea L. Anderson; Wendy J. McGInnls

1990-01-01

By 2000, prices are expected to rise significantly for medium-grade logs and modestly for low-grade logs. World economic cycles may obscure, however, the upward price trends. Exports from the United States of medium grades are expected to remain stable, while volumes of lower grades are projected to remain level through 1995 and then decline because of competition....

Integrated HIFU Drive System on a Chip for CMUT-Based Catheter Ablation System.

PubMed

Farhanieh, Omid; Sahafi, Ali; Bardhan Roy, Rupak; Ergun, Arif Sanli; Bozkurt, Ayhan

2017-06-01

Conventional High Intensity Focused Ultrasound (HIFU) is a therapeutic modality which is extracorporeally administered. In applications where a relatively small HIFU lesion is required, an intravascular HIFU probe can be deployed to the ablation site. In this paper, we demonstrate the design and implementation a fully integrated HIFU drive system on a chip to be placed on a 6 Fr catheter probe. An 8-element capacitive micromachined ultrasound transducer (CMUT) ring array of 2 mm diameter has been used as the ultrasound source. The driver chip is fabricated in 0.35 μm AMS high-voltage CMOS technology and comprises eight continuous-wave (CW) high-voltage CMUT drivers (10.9 ns and 9.4 ns rise and fall times at 20 V pp output into a 15 pF), an eight-channel digital beamformer (8-12 MHz output frequency with 11.25 ° phase accuracy) and a phase locked loop with an integrated VCO as a tunable clock source (128-192 MHz). The chip occupies 1.85 × 1.8 mm 2 area including input and output (I/O) pads. When the transducer array is immersed in sunflower oil and driven by the IC with eight 20 V pp CW pulses at 10 MHz, real-time thermal images of the HIFU beam indicate that the focal temperature rises by 16.8  ° C in 11 seconds. Each HV driver consumes around 67 mW of power when driving the CMUT array at 10 MHz, which adds up to 560 mW for the whole chip. FEM based analysis reveals that the outer surface temperature of the catheter is expected to remain below the 42  ° C tissue damage limit during therapy.

Is Snowmelt Initiation Independent of Elevation?

NASA Astrophysics Data System (ADS)

Lundquist, J. D.; Dettinger, M. D.; Cayan, D. R.

2002-12-01

Recent studies (Peterson et al, Dettinger and Cayan) have shown that the Western rivers routinely monitored by the USGS all rise together each spring, suggesting an organized signal of snowmelt initiation across the region. These are all large basins (over 100 km2), spanning similar ranges of aspect and elevation. However, within a given basin, should we expect the spring pulse of snowmelt to occur at the same time in a 470 km2 basin gauged at 1200 m as in a 2 km2 glacial cirque gauged at 3200 m? Should streamflow from a north-facing cirque rise and peak at the same time as that from a south-facing cirque? Data from sub-basins of the Tuolumne and Merced Rivers within Yosemite National Park, from small lake basins throughout the Sierra Nevada Mountains, and from CDWR snow pillow stations throughout the central Sierra Nevada suggest that the answer to both of these questions is yes. Elevation and aspect exert strong influences on air temperature and solar radiation, which are important factors in controlling snowmelt. Why, then, does melt appear uniform across the Sierra Nevada each spring? Do air temperature and solar radiation differ less than previously supposed? Do snowpack properties create some kind of buffer or limit on melt rates that make small-scale meteorological differences less important? If initial melt rates are uniform throughout the basin, why do high-altitude, north-facing cirques retain their snow-cover the longest? Do they start out with more snow, or do the dominant factors influencing melt rates and supply change as the season progresses? This study uses the available data to examine these hypotheses.

Switching Characteristics of a 4H-SiC Based Bipolar Junction Transistor to 200 C

NASA Technical Reports Server (NTRS)

Niedra, Janis M.

2006-01-01

Static curves and resistive load switching characteristics of a 600 V, 4 A rated, SiC-based NPN bipolar power transistor (BJT) were observed at selected temperatures from room to 200 C. All testing was done in a pulse mode at low duty cycle (approx.0.1 percent). Turn-on was driven by an adjustable base current pulse and turn-off was accelerated by a negative base voltage pulse of 7 V. These base drive signals were implemented by 850 V, gated power pulsers, having rise-times of roughly 10 ns, or less. Base charge sweep-out with a 7 V negative pulse did not produce the large reverse base current pulse seen in a comparably rated Si-based BJT. This may be due to a very low charge storage time. The decay of the collector current was more linear than its exponential-like rise. Switching observations were done at base drive currents (I(sub B)) up to 400 mA and collector currents (I(sub C)) up to 4 A, using a 100 Omega non-inductive load. At I(sub B) = 400 mA and I(sub C) = 4 A, turn-on times typically varied from 80 to 94 ns, over temperatures from 23 to 200 C. As expected, lowering the base drive greatly extended the turn-on time. Similarly, decreasing the load current to I(sub C) = 1 A with I(sub B) = 400 mA produced turn-on times as short as 34 ns. Over the 23 to 200 C range, with I(sub B) = 400 mA and I(sub C) = 4 A, turn-off times were in the range of 72 to 84 ns with the 7 V sweep-out.

Changes in river water temperature between 1980 and 2012 in Yongan watershed, eastern China: Magnitude, drivers and models

NASA Astrophysics Data System (ADS)

Chen, Dingjiang; Hu, Minpeng; Guo, Yi; Dahlgren, Randy A.

2016-02-01

Climate warming is expected to have major impacts on river water quality, water column/hyporheic zone biogeochemistry and aquatic ecosystems. A quantitative understanding of spatio-temporal air (Ta) and water (Tw) temperature dynamics is required to guide river management and to facilitate adaptations to climate change. This study determined the magnitude, drivers and models for increasing Tw in three river segments of the Yongan watershed in eastern China. Over the 1980-2012 period, Tw in the watershed increased by 0.029-0.046 °C yr-1 due to a ∼0.050 °C yr-1 increase of Ta and changes in local human activities (e.g., increasing developed land and population density and decreasing forest area). A standardized multiple regression model was developed for predicting annual Tw (R2 = 0.88-0.91) and identifying/partitioning the impact of the principal drivers on increasing Tw:Ta (76 ± 1%), local human activities (14 ± 2%), and water discharge (10 ± 1%). After normalizing water discharge, climate warming and local human activities were estimated to contribute 81-95% and 5-19% of the observed rising Tw, respectively. Models forecast a 0.32-1.76 °C increase in Tw by 2050 compared with the 2000-2012 baseline condition based on four future scenarios. Heterogeneity of warming rates existed across seasons and river segments, with the lower flow river and dry season demonstrating a more pronounced response to climate warming and human activities. Rising Tw due to changes in climate, local human activities and hydrology has a considerable potential to aggravate river water quality degradation and coastal water eutrophication in summer. Thus it should be carefully considered in developing watershed management strategies in response to climate change.

Climate change impacts on the Lehman-Baker Creek drainage in the Great Basin National Park

NASA Astrophysics Data System (ADS)

Volk, J. M.

2013-12-01

Global climate models (GCMs) forced by increased CO2 emissions forecast anomalously dry and warm trends over the southwestern U.S. for the 21st century. The effect of warmer conditions may result in decreased surface water resources within the Great Basin physiographic region critical for ecology, irrigation and municipal water supply. Here we use downscaled GCM output from the A2 and B1 greenhouse gas emission scenarios to force a Precipitation-Runoff Modeling System (PRMS) watershed model developed for the Lehman and Baker Creeks Drainage (LBCD) in the Great Basin National Park, NV for a century long time period. The goal is to quantify the effects of rising temperature to the water budget in the LBCD at monthly and annual timescales. Dynamically downscaled GCM projections are attained from the NSF EPSCoR Nevada Infrastructure for Climate Change Science, Education, and Outreach project and statistically downscaled output is retrieved from the "U.S. Bias Corrected and Downscaled WCRP CMIP3 Climate Projections". Historical daily climate and streamflow data have been collected simultaneously for periods extending 20 years or longer. Mann-Kendal trend test results showed a statistically significant (α= 0.05) long-term rising trend from 1895 to 2012 in annual and monthly average temperatures for the study area. A grid-based, PRMS watershed model of the LBCD has been created within ArcGIS 10, and physical parameters have been estimated at a spatial resolution of 100m. Simulation results will be available soon. Snow cover is expected to decrease and peak runoff to occur earlier in the spring, resulting in increased runoff, decreased infiltration/recharge, decreased baseflows, and decreased evapo-transpiration.

IMPERVIOUS COVER AS A REGIONAL INDICATOR

EPA Science Inventory

Increases in impervious surface area in a watershed gives rise to changes in stream hydrology, stream channel morphology, increased pollutant runoff, and an increase in stream water temperature. These physical changes in the stream systems in turn give rise to impacts on stream ...

Rising temperatures place cities at risk

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

Tickell, C.

1996-12-31

This article focuses on vulerability of urban areas as the global temperature rises and the climate changes. Basic resources - food, water, building materials, and fuel - must be brought in; the external resource base is being depleted as a result of deforestation; disposal of wastes both toxic and not is an added stress; and health effected by air and water pollution is vulnerable. This article discusses these aspects along with the sociology of urban areas in our current world. Historical prospectives are included.

Heat release effects in a turbulent, reacting shear layer

NASA Astrophysics Data System (ADS)

Hermanson, James Carl

The effects of heat release were studied in a planar, gaseous reacting mixing layer formed between free streams containing hydrogen and fluorine in inert diluents. Sufficiently high concentrations of reactants were employed to produce adiabatic flame temperature rises of up to 940 K (1240 K absolute). The Reynolds number at the measuring station, based on velocity difference, 1% temperature thickness and cold kinematic viscosity was approximately 6x10^4. The temperature field was measured with cold wire resistance thermometers and thermocouples. Flow visualization was accomplished by schlieren spark and motion picture photography. Mean velocity information was extracted from mean pitot probe dynamic pressure measurements.Though the displacement thickness of the layer, for zero streamwise pressure gradient, increased with increasing heat release, the actual growth rate of the layer did not increase, but instead decreased slightly. The overall entrainment into the layer was seen to be substantially reduced as a consequence of heat release. Calculations showed that the decrease in layer growth rate can be accounted for by a corresponding reduction in turbulent shear stress.The mean temperature rise profiles, normalized by the adiabatic flame temperature rise, were not greatly changed in shape by heat release. A small decrease in normalized mean temperature rise with heat release was observed. Large scale coherent structures were observed to persist at all levels of heat release in this investigation. The mean structure spacing decreased with increasing temperature. This decrease exceeded the rate of layer growth rate reduction, and suggests that the mechanisms of vortex amalgamation were, to some extent, inhibited by heat release.Imposition of a favorable pressure gradient resulted in additional thinning of the layer, and caused a slight increase in the mixing and amount of chemical product formation. The change in layer growth rate can be shown to be related to a change in free stream velocity ratio induced by pressure gradient.

Agroecosystem productivity in a warmer and CO2 enriched atmosphere

NASA Astrophysics Data System (ADS)

Bernacchi, Carl; Köhler, Iris; Ort, Donald; Long, Steven; Clemente, Thomas

2017-04-01

A number of in-field manipulative experiments have been conducted that address the response of key ecosystem services of major agronomic species to rising CO2. Global warming, however, is inextricably linked to rising greenhouse gases in general, of which CO2 is the most dominant. Therefore, agroecosystem functioning in future conditions requires an understanding of plant responses to both rising CO2 and increased temperatures. Few in-field manipulative experiments have been conducted that supplement both heating and CO2 above background concentrations. Here, the results of six years of experimentation using a coupled Free Air CO2 Enrichment (FACE) technology with variable output infrared heating arrays are reported. The manipulative experiment increased temperatures (+ 3.5˚ C) and CO2 (+ 200 μmol mol-1) above background levels for on two major agronomic crop species grown throughout the world, Zea mays (maize) and Glycine max (soybean). The first phase of this research addresses the response of plant physiological parameters to growth in elevated CO2 and warmer temperatures for maize and soybean grown in an open-air manipulative experiment. The results show that any increase in ecosystem productivity associated with rising CO2 is either similar or is offset by growth at higher temperatures, inconsistent with the perceived benefits of higher CO2 plus warmer temperatures on agroecosystem productivity. The second phase of this research addresses the opportunity to genetically modify soybean to allow for improved productivity under high CO2 and warmer temperatures by increasing a key photosynthetic carbon reduction cycle enzyme, SPBase. The results from this research demonstrates that manipulation of the photosynthetic pathway can lead to higher productivity in high CO2 and temperature relative to the wild-type control soybean. Overall, this research advances the understanding of the physiological responses of two major crops, and the impact on ecosystem services, to atmospheric conditions with the ultimate goals of better understanding agronomic responses to global change and improved representation of these processes in ecosystem models.

Global warming and hepatotoxin production by cyanobacteria: what can we learn from experiments?

PubMed

El-Shehawy, Rehab; Gorokhova, Elena; Fernández-Piñas, Francisca; del Campo, Francisca F

2012-04-01

Global temperature is expected to rise throughout this century, and blooms of cyanobacteria in lakes and estuaries are predicted to increase with the current level of global warming. The potential environmental, economic and sanitation repercussions of these blooms have attracted considerable attention among the world's scientific communities, water management agencies and general public. Of particular concern is the worldwide occurrence of hepatotoxic cyanobacteria posing a serious threat to global public health. Here, we highlight plausible effects of global warming on physiological and molecular changes in these cyanobacteria and resulting effects on hepatotoxin production. We also emphasize the importance of understanding the natural biological function(s) of hepatotoxins, various mechanisms governing their synthesis, and climate-driven changes in food-web interactions, if we are to predict consequences of the current and projected levels of global warming for production and accumulation of hepatotoxins in aquatic ecosystems. Copyright © 2011 Elsevier Ltd. All rights reserved.

Membrane interactions of ionic liquids and imidazolium salts.

PubMed

Wang, Da; Galla, Hans-Joachim; Drücker, Patrick

2018-06-01

Room-temperature ionic liquids (RTILs) have attracted considerable attention in recent years due to their versatile properties such as negligible volatility, inflammability, high extractive selectivity and thermal stability. In general, RTILs are organic salts with a melting point below ~100 °C determined by the asymmetry of at least one of their ions. Due to their amphiphilic character, strong interactions with biological materials can be expected. However, rising attention has appeared towards their similarity and interaction with biomolecules. By employing structural modifications, the biochemical properties of RTILs can be designed to mimic lipid structures and to tune their hydrophobicity towards a lipophilic behavior. This is evident for the interaction with lipid-membranes where some of these compounds present membrane-disturbing effects or cellular toxicity. Moreover, they can form micelles or lipid-like bilayer structures by themselves. Both aspects, cellular effects and membrane-forming capacities, of a novel class of lipophilic imidazolium salts will be discussed.

Effects of sonication radiation on oil recovery by ultrasonic waves stimulated water-flooding.

PubMed

Mohammadian, Erfan; Junin, Radzuan; Rahmani, Omeid; Idris, Ahmad Kamal

2013-02-01

Due to partial understanding of mechanisms involved in application of ultrasonic waves as enhanced oil recovery method, series of straight (normal), and ultrasonic stimulated water-flooding experiments were conducted on a long unconsolidated sand pack using ultrasonic transducers. Kerosene, vaseline, and SAE-10 (engine oil) were used as non-wet phase in the system. In addition, a series of fluid flow and temperature rise experiments were conducted using ultrasonic bath in order to enhance the understanding about contributing mechanisms. 3-16% increase in the recovery of water-flooding was observed. Emulsification, viscosity reduction, and cavitation were identified as contributing mechanisms. The findings of this study are expected to increase the insight to involving mechanisms which lead to improving the recovery of oil as a result of application of ultrasound waves. Copyright © 2012 Elsevier B.V. All rights reserved.

Redox Effects on Organic Matter Storage in Coastal Sediments During the Holocene: A Biomarker/Proxy Perspective

NASA Astrophysics Data System (ADS)

Bianchi, Thomas S.; Schreiner, Kathryn M.; Smith, Richard W.; Burdige, David J.; Woodard, Stella; Conley, Daniel J.

2016-06-01

Coastal margins play a significant role in the burial of organic matter (OM) on Earth. These margins vary considerably with respect to their efficiency in OM burial and to the amounts and periodicity of their OM delivery, depending in large part on whether they are passive or active margins. In the context of global warming, these coastal regions are expected to experience higher water temperatures, changes in riverine inputs of OM, and sea level rise. Low-oxygen conditions continue to expand around the globe in estuarine regions (i.e., hypoxic zones) and shelf regions (i.e., oxygen minimum zones), which will impact the amounts and sources of OM stored in these regions. In this review, we explore how these changes are impacting the storage of OM and the preservation of sedimentary biomarkers, used as proxies to reconstruct environmental change, in coastal margins.

Accelerating Tropicalization and the Transformation of Temperate Seagrass Meadows

PubMed Central

Hyndes, Glenn A.; Heck, Kenneth L.; Vergés, Adriana; Harvey, Euan S.; Kendrick, Gary A.; Lavery, Paul S.; McMahon, Kathryn; Orth, Robert J.; Pearce, Alan; Vanderklift, Mathew; Wernberg, Thomas; Whiting, Scott; Wilson, Shaun

2016-01-01

Abstract Climate-driven changes are altering production and functioning of biotic assemblages in terrestrial and aquatic environments. In temperate coastal waters, rising sea temperatures, warm water anomalies and poleward shifts in the distribution of tropical herbivores have had a detrimental effect on algal forests. We develop generalized scenarios of this form of tropicalization and its potential effects on the structure and functioning of globally significant and threatened seagrass ecosystems, through poleward shifts in tropical seagrasses and herbivores. Initially, we expect tropical herbivorous fishes to establish in temperate seagrass meadows, followed later by megafauna. Tropical seagrasses are likely to establish later, delayed by more limited dispersal abilities. Ultimately, food webs are likely to shift from primarily seagrass-detritus to more direct-consumption-based systems, thereby affecting a range of important ecosystem services that seagrasses provide, including their nursery habitat role for fishery species, carbon sequestration, and the provision of organic matter to other ecosystems in temperate regions. PMID:28533562

Accelerating Tropicalization and the Transformation of Temperate Seagrass Meadows.

PubMed

Hyndes, Glenn A; Heck, Kenneth L; Vergés, Adriana; Harvey, Euan S; Kendrick, Gary A; Lavery, Paul S; McMahon, Kathryn; Orth, Robert J; Pearce, Alan; Vanderklift, Mathew; Wernberg, Thomas; Whiting, Scott; Wilson, Shaun

2016-11-01

Climate-driven changes are altering production and functioning of biotic assemblages in terrestrial and aquatic environments. In temperate coastal waters, rising sea temperatures, warm water anomalies and poleward shifts in the distribution of tropical herbivores have had a detrimental effect on algal forests. We develop generalized scenarios of this form of tropicalization and its potential effects on the structure and functioning of globally significant and threatened seagrass ecosystems, through poleward shifts in tropical seagrasses and herbivores. Initially, we expect tropical herbivorous fishes to establish in temperate seagrass meadows, followed later by megafauna. Tropical seagrasses are likely to establish later, delayed by more limited dispersal abilities. Ultimately, food webs are likely to shift from primarily seagrass-detritus to more direct-consumption-based systems, thereby affecting a range of important ecosystem services that seagrasses provide, including their nursery habitat role for fishery species, carbon sequestration, and the provision of organic matter to other ecosystems in temperate regions.

Multidecadal increase in North Atlantic coccolithophores and the potential role of rising CO₂.

PubMed

Rivero-Calle, Sara; Gnanadesikan, Anand; Del Castillo, Carlos E; Balch, William M; Guikema, Seth D

2015-12-18

As anthropogenic carbon dioxide (CO2) emissions acidify the oceans, calcifiers generally are expected to be negatively affected. However, using data from the Continuous Plankton Recorder, we show that coccolithophore occurrence in the North Atlantic increased from ~2 to more than 20% from 1965 through 2010. We used random forest models to examine more than 20 possible environmental drivers of this change, finding that CO2 and the Atlantic Multidecadal Oscillation were the best predictors, leading us to hypothesize that higher CO2 levels might be encouraging growth. A compilation of 41 independent laboratory studies supports our hypothesis. Our study shows a long-term basin-scale increase in coccolithophores and suggests that increasing CO2 and temperature have accelerated the growth of a phytoplankton group that is important for carbon cycling. Copyright © 2015, American Association for the Advancement of Science.

The microstructure and properties of rapidly solidified, dispersion-strengthened NiAl

NASA Technical Reports Server (NTRS)

Jha, S. C.; Ray, R.

1990-01-01

An advanced rapid solidification technology for processing reactive and refractory alloys, utilized to produce large quantities of melt-spun filaments of NiAl, is presented. The melt-spun filaments are pulverized to fine particle sizes, and subsequently consolidated by hot extrusion or hot isostatic pressing. Rapid solidification process gives rise to very fine-grained microstructures. However, exposure to elevated temperature during hot consolidation leads to grain growth. Alloying agents such as borides, carbides, and tungsten can pin the grain boundaries and retard the grain growth. Various alloy compositions are investigated. The eventual goal is to utilize the hot-extruded and forged stock to grow single-crystal NiAl blades for advanced gas-turbine engine applications. Single-crystal NiAl, containing a uniform dispersion of carbide strengthening precipitates, is expected to lead to highly creep-resistant turbine blades, and is of considerable interest to the aerospace propulsion industry.

Urbanisation and greening of Indian cities: Problems, practices, and policies.

PubMed

Imam, Aabshar U K; Banerjee, Uttam Kumar

2016-05-01

Progress of the Indian economy is threatened by the impact of climate change. Generation of urban heat islands (UHIs), waning of urban green cover, increase in carbon emissions and air pollution deteriorate the living environment. Rise in urban temperatures and heat stress induced mortality remain major concerns. Although the National Action Plan on Climate Change emphasises the national missions of 'enhanced energy efficiency', and 'green India', little research has been devoted to explore the passive cooling potential of urban greenery in India, thus lending uniqueness to this study. The manifestations of unplanned urban development (UHIs, escalated carbon emissions, air pollution) are discussed and corroborated with identification of contributory factors. Contemporary greening practices and bye-laws in four major Indian cities (New Delhi, Pune, Chennai, and Visakhapatnam) are analysed and compared with global best practices. The findings are used to propose planning guidelines which are expected to assist in consolidating natural sustainability of emerging economies.

Microstructure-Property Correlation in Low-Si Steel Processed Through Quenching and Nonisothermal Partitioning

NASA Astrophysics Data System (ADS)

Bansal, Gaurav K.; Rajinikanth, V.; Ghosh, Chiradeep; Srivastava, V. C.; Kundu, S.; Ghosh Chowdhury, S.

2018-05-01

In the present investigation, an attempt has been made to stabilize austenite by carbon partitioning through quenching and nonisothermal partitioning (Q&P) technique. This will eliminate the need for additional heat-treatment facility to perform isothermal partitioning or tempering process. The presence of retained austenite in the microstructure helps in increasing the toughness, which in turn is expected to improve the abrasion resistance of steels. The carbon partitioning from different quench temperatures has been performed on two different alloys, with low-Si content (0.5 wt pct), in a salt bath furnace atmosphere, the cooling profile of which closely resembles the industrially produced hot-rolled coil cooling. The results show that the stabilization of retained austenite is possible and gives rise to increased work hardening, better impact toughness and abrasive wear loss comparable to that of a fully martensitic microstructure. In contrast, tempered martensite exhibits better wear properties at the expense of impact toughness.

Influence of climate change on the incidence and impact of arenavirus diseases: a speculative assessment.

PubMed

Clegg, J C

2009-06-01

The current worldwide incidence of viral haemorrhagic fevers caused by arenaviruses is briefly reviewed. The recently published Assessment Report of the Intergovernmental Panel on Climate Change has described the changes in global climate that are expected to occur over the course of the present century and beyond. Climate modelling and forecasting have not yet reached the stage where confident predictions of regional changes at the level of a virus endemic area can be made. However, in the regions where pathogenic arenaviruses now circulate, significant effects are likely to include increases in surface temperature, changes in the extent and distribution of rainfall, the occurrence of extreme weather events, glacier retreat, and coastal flooding as a result of sea level rise. The possible impact of these changes on the geographical location and the incidence of arenavirus diseases and its human impact are discussed.

The Impacts of Rising Temperatures on Aircraft Takeoff Performance

NASA Technical Reports Server (NTRS)

Coffel, Ethan; Thompson, Terence R.; Horton, Radley M.

2017-01-01

Steadily rising mean and extreme temperatures as a result of climate change will likely impact the air transportation system over the coming decades. As air temperatures rise at constant pressure, air density declines, resulting in less lift generation by an aircraft wing at a given airspeed and potentially imposing a weight restriction on departing aircraft. This study presents a general model to project future weight restrictions across a fleet of aircraft with different takeoff weights operating at a variety of airports. We construct performance models for five common commercial aircraft and 19 major airports around the world and use projections of daily temperatures from the CMIP5 model suite under the RCP 4.5 and RCP 8.5 emissions scenarios to calculate required hourly weight restriction. We find that on average, 10 - 30% of annual flights departing at the time of daily maximum temperature may require some weight restriction below their maximum takeoff weights, with mean restrictions ranging from 0.5 to 4% of total aircraft payload and fuel capacity by mid- to late century. Both mid-sized and large aircraft are affected, and airports with short runways and high temperatures, or those at high elevations, will see the largest impacts. Our results suggest that weight restriction may impose a non-trivial cost on airlines and impact aviation operations around the world and that adaptation may be required in aircraft design, airline schedules, and/or runway lengths.

Role of temperature dependence of optical properties in laser irradiation of biological tissue

NASA Astrophysics Data System (ADS)

Rastegar, Sohi; Kim, Beop-Min; Jacques, Steven L.

1992-08-01

Optical properties of biological tissue can change as a result of thermal denaturation due to temperature rise; a familiar example is whitening observed in cooking egg-white. Changes in optical properties with temperature have been reported in the literature. Temperature rise due to laser irradiation is a function of the optical properties of tissue which themselves are a function of temperature of the tissue. This creates a coupling between light and temperature fields for biological tissue under laser irradiation. The effects of this coupling on the temperature response and light distribution may play an important role in dosimetry consideration for therapeutic as well as diagnostic application of lasers in medicine. In a previous study this problem was addressed in one dimension, for short irradiation exposures, using certain simplifying assumptions. The purpose of this research was to develop a mathematical model for dynamic optical changes with thermal denaturation and a computer program for simulation of these effects for a multi-dimensional geometry.

Compare ultrasound-mediated heating and cavitation between flowing polymer- and lipid-shelled microbubbles during focused ultrasound exposures.

PubMed

Zhang, Siyuan; Zong, Yujin; Wan, Mingxi; Yu, Xiaojun; Fu, Quanyou; Ding, Ting; Zhou, Fanyu; Wang, Supin

2012-06-01

This paper compares the efficiency of flowing polymer- and lipid-shelled microbubbles (MBs) in the heating and cavitation during focused ultrasound exposures. Temperature and cavitation activity were simultaneously measured as the two types of shelled MBs and saline flowing through a 3 mm diameter vessel in the phantom with varying flow velocities (0-20 cm/s) at different acoustic power levels (0.6-20 W) with each exposure for 5 s. Temperature and cavitation for the lipid-shelled MBs were higher than those for the polymer-shelled MBs. Temperature rise decreased with increasing flow velocities for the two types of shelled MBs and saline at acoustic power 1.5 W. At acoustic power 11.1 W, temperature rise increased with increasing flow velocities for the lipid-shelled MBs. For the polymer-shelled MBs, the temperature rise increased with increasing flow velocities from 3-15 cm/s and decreased at 20 cm/s. Cavitation increased with increasing flow velocity for the two shelled MBs and there were no significant changes of cavitation with increasing flow velocities for saline. These results suggested that lipid-shelled MBs may have a greater efficiency than polymer-shelled MBs in heating and cavitation during focused ultrasound exposures.

46 CFR 164.007-5 - Test requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... thermocouples on the unexposed surface described in § 164.007-4(f)(2) will not rise more than 139 °C. (250 °F... through metallic connection, rise more than 181 °C. (325 °F.) above the original temperature at the end of...

46 CFR 164.007-5 - Test requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... thermocouples on the unexposed surface described in § 164.007-4(f)(2) will not rise more than 139 °C. (250 °F... through metallic connection, rise more than 181 °C. (325 °F.) above the original temperature at the end of...

Rhode Island Salt Marshes: Elevation Capital and Resilience to Sea Level Rise

EPA Science Inventory

Tidal salt marsh is especially sensitive to deterioration due to the effects of accelerated sea level rise when combined with other anthropogenically linked stressors, including crab herbivory, changes in tidal hydrology, nutrient loading, dam construction, changes in temperature...